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littlefs/lfs.c
Christopher Haster 6d4248c685 util: Cleaned up lfs_util.h 
This one was a bit more involved.

Removes utils that are no longer useful, and made sure some of the
name/API changes over time are adopted consistently:

- lfs_npw2 -> lfs_nlog2
- lfs_tole32_ -> lfs_tole32
- lfs_fromle32_ -> lfs_fromle32

Also did another pass for lfs_ prefixes on mem/str functions. The habit
to use the naked variants of these is hard to break!
2025-05-27 21:34:12 -05:00

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/*
* The little filesystem
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "lfs.h"
#include "lfs_util.h"
// internally used disk-comparison enum
//
// note LT < EQ < GT
enum lfs_scmp {
LFS_CMP_LT = 0, // disk < query
LFS_CMP_EQ = 1, // disk = query
LFS_CMP_GT = 2, // disk > query
};
typedef int lfs_scmp_t;
// this is just a hint that the function returns a bool + err union
typedef int lfs_sbool_t;
/// Simple bd wrappers (asserts go here) ///
static int lfsr_bd_read__(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
void *buffer, lfs_size_t size) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
// must be aligned
LFS_ASSERT(off % lfs->cfg->read_size == 0);
LFS_ASSERT(size % lfs->cfg->read_size == 0);
// bd read
int err = lfs->cfg->read(lfs->cfg, block, off, buffer, size);
LFS_ASSERT(err <= 0);
if (err) {
LFS_INFO("Bad read 0x%"PRIx32".%"PRIx32" %"PRIu32" (%d)",
block, off, size, err);
return err;
}
return 0;
}
static int lfsr_bd_prog__(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
const void *buffer, lfs_size_t size) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
// must be aligned
LFS_ASSERT(off % lfs->cfg->prog_size == 0);
LFS_ASSERT(size % lfs->cfg->prog_size == 0);
// bd prog
int err = lfs->cfg->prog(lfs->cfg, block, off, buffer, size);
LFS_ASSERT(err <= 0);
if (err) {
LFS_INFO("Bad prog 0x%"PRIx32".%"PRIx32" %"PRIu32" (%d)",
block, off, size, err);
return err;
}
return 0;
}
static int lfsr_bd_erase__(lfs_t *lfs, lfs_block_t block) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
// bd erase
int err = lfs->cfg->erase(lfs->cfg, block);
LFS_ASSERT(err <= 0);
if (err) {
LFS_INFO("Bad erase 0x%"PRIx32" (%d)",
block, err);
return err;
}
return 0;
}
static int lfsr_bd_sync__(lfs_t *lfs) {
// bd sync
int err = lfs->cfg->sync(lfs->cfg);
LFS_ASSERT(err <= 0);
if (err) {
LFS_INFO("Bad sync (%d)", err);
return err;
}
return 0;
}
/// Caching block device operations ///
static inline void lfsr_bd_droprcache(lfs_t *lfs) {
lfs->rcache.size = 0;
}
static inline void lfsr_bd_droppcache(lfs_t *lfs) {
lfs->pcache.size = 0;
}
// caching read that lends you a buffer
//
// note hint has two conveniences:
// 0 => minimal caching
// -1 => maximal caching
static int lfsr_bd_readnext(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
lfs_size_t size,
const uint8_t **buffer_, lfs_size_t *size_) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t hint_ = lfs_max(hint, size); // make sure hint >= size
while (true) {
lfs_size_t d = hint_;
// already in pcache?
if (block == lfs->pcache.block
&& off < lfs->pcache.off + lfs->pcache.size) {
if (off >= lfs->pcache.off) {
*buffer_ = &lfs->pcache.buffer[off-lfs->pcache.off];
*size_ = lfs_min(
lfs_min(d, size),
lfs->pcache.size - (off-lfs->pcache.off));
return 0;
}
// pcache takes priority
d = lfs_min(d, lfs->pcache.off - off);
}
// already in rcache?
if (block == lfs->rcache.block
&& off < lfs->rcache.off + lfs->rcache.size
&& off >= lfs->rcache.off) {
*buffer_ = &lfs->rcache.buffer[off-lfs->rcache.off];
*size_ = lfs_min(
lfs_min(d, size),
lfs->rcache.size - (off-lfs->rcache.off));
return 0;
}
// drop rcache in case read fails
lfsr_bd_droprcache(lfs);
// load into rcache, above conditions can no longer fail
//
// note it's ok if we overlap the pcache a bit, pcache always
// takes priority until flush, which updates the rcache
lfs_size_t off__ = lfs_aligndown(off, lfs->cfg->read_size);
lfs_size_t size__ = lfs_alignup(
lfs_min(
// watch out for overflow when hint_=-1!
(off-off__) + lfs_min(
d,
lfs->cfg->block_size - off),
lfs->cfg->rcache_size),
lfs->cfg->read_size);
int err = lfsr_bd_read__(lfs, block, off__,
lfs->rcache.buffer, size__);
if (err) {
return err;
}
lfs->rcache.block = block;
lfs->rcache.off = off__;
lfs->rcache.size = size__;
}
}
// caching read
//
// note hint has two conveniences:
// 0 => minimal caching
// -1 => maximal caching
static int lfsr_bd_read(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
void *buffer, lfs_size_t size) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t off_ = off;
lfs_size_t hint_ = lfs_max(hint, size); // make sure hint >= size
uint8_t *buffer_ = buffer;
lfs_size_t size_ = size;
while (size_ > 0) {
lfs_size_t d = hint_;
// already in pcache?
if (block == lfs->pcache.block
&& off_ < lfs->pcache.off + lfs->pcache.size) {
if (off_ >= lfs->pcache.off) {
d = lfs_min(
lfs_min(d, size_),
lfs->pcache.size - (off_-lfs->pcache.off));
lfs_memcpy(buffer_,
&lfs->pcache.buffer[off_-lfs->pcache.off],
d);
off_ += d;
hint_ -= d;
buffer_ += d;
size_ -= d;
continue;
}
// pcache takes priority
d = lfs_min(d, lfs->pcache.off - off_);
}
// already in rcache?
if (block == lfs->rcache.block
&& off_ < lfs->rcache.off + lfs->rcache.size) {
if (off_ >= lfs->rcache.off) {
d = lfs_min(
lfs_min(d, size_),
lfs->rcache.size - (off_-lfs->rcache.off));
lfs_memcpy(buffer_,
&lfs->rcache.buffer[off_-lfs->rcache.off],
d);
off_ += d;
hint_ -= d;
buffer_ += d;
size_ -= d;
continue;
}
// rcache takes priority
d = lfs_min(d, lfs->rcache.off - off_);
}
// bypass rcache?
if (off_ % lfs->cfg->read_size == 0
&& lfs_min(d, size_) >= lfs_min(hint_, lfs->cfg->rcache_size)
&& lfs_min(d, size_) >= lfs->cfg->read_size) {
d = lfs_aligndown(size_, lfs->cfg->read_size);
int err = lfsr_bd_read__(lfs, block, off_, buffer_, d);
if (err) {
return err;
}
off_ += d;
hint_ -= d;
buffer_ += d;
size_ -= d;
continue;
}
// drop rcache in case read fails
lfsr_bd_droprcache(lfs);
// load into rcache, above conditions can no longer fail
//
// note it's ok if we overlap the pcache a bit, pcache always
// takes priority until flush, which updates the rcache
lfs_size_t off__ = lfs_aligndown(off_, lfs->cfg->read_size);
lfs_size_t size__ = lfs_alignup(
lfs_min(
// watch out for overflow when hint_=-1!
(off_-off__) + lfs_min(
lfs_min(hint_, d),
lfs->cfg->block_size - off_),
lfs->cfg->rcache_size),
lfs->cfg->read_size);
int err = lfsr_bd_read__(lfs, block, off__,
lfs->rcache.buffer, size__);
if (err) {
return err;
}
lfs->rcache.block = block;
lfs->rcache.off = off__;
lfs->rcache.size = size__;
}
return 0;
}
// needed in lfsr_bd_prog_ for prog validation
#ifdef LFS_CKPROGS
static inline bool lfsr_m_isckprogs(uint32_t flags);
#endif
static lfs_scmp_t lfsr_bd_cmp(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
const void *buffer, lfs_size_t size);
// low-level prog stuff
static int lfsr_bd_prog_(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
const void *buffer, lfs_size_t size,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
// prog to disk
int err = lfsr_bd_prog__(lfs, block, off, buffer, size);
if (err) {
return err;
}
#ifdef LFS_CKPROGS
// checking progs?
if (lfsr_m_isckprogs(lfs->flags)) {
// pcache should have been dropped at this point
LFS_ASSERT(lfs->pcache.size == 0);
// invalidate rcache, we're going to clobber it anyways
lfsr_bd_droprcache(lfs);
lfs_scmp_t cmp = lfsr_bd_cmp(lfs, block, off, 0,
buffer, size);
if (cmp < 0) {
return cmp;
}
if (cmp != LFS_CMP_EQ) {
LFS_WARN("Found ckprog mismatch 0x%"PRIx32".%"PRIx32" %"PRId32,
block, off, size);
return LFS_ERR_CORRUPT;
}
}
#endif
// update rcache if we can
if (block == lfs->rcache.block
&& off <= lfs->rcache.off + lfs->rcache.size) {
lfs->rcache.off = lfs_min(off, lfs->rcache.off);
lfs->rcache.size = lfs_min(
(off-lfs->rcache.off) + size,
lfs->cfg->rcache_size);
lfs_memcpy(&lfs->rcache.buffer[off-lfs->rcache.off],
buffer,
lfs->rcache.size - (off-lfs->rcache.off));
}
// optional aligned checksum
if (cksum && align) {
*cksum = lfs_crc32c(*cksum, buffer, size);
}
return 0;
}
// flush the pcache
static int lfsr_bd_flush(lfs_t *lfs, uint32_t *cksum, bool align) {
if (lfs->pcache.size != 0) {
// must be in-bounds
LFS_ASSERT(lfs->pcache.block < lfs->block_count);
// must be aligned
LFS_ASSERT(lfs->pcache.off % lfs->cfg->prog_size == 0);
lfs_size_t size = lfs_alignup(lfs->pcache.size, lfs->cfg->prog_size);
// make this cache available, if we error anything in this cache
// would be useless anyways
lfsr_bd_droppcache(lfs);
// flush
int err = lfsr_bd_prog_(lfs, lfs->pcache.block,
lfs->pcache.off, lfs->pcache.buffer, size,
cksum, align);
if (err) {
return err;
}
}
return 0;
}
// caching prog that lends you a buffer
//
// with optional checksum
static int lfsr_bd_prognext(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
lfs_size_t size,
uint8_t **buffer_, lfs_size_t *size_,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
while (true) {
// active pcache?
if (lfs->pcache.block == block
&& lfs->pcache.size != 0) {
// fits in pcache?
if (off < lfs->pcache.off + lfs->cfg->pcache_size) {
// you can't prog backwards silly
LFS_ASSERT(off >= lfs->pcache.off);
// expand the pcache?
lfs->pcache.size = lfs_min(
(off-lfs->pcache.off) + size,
lfs->cfg->pcache_size);
*buffer_ = &lfs->pcache.buffer[off-lfs->pcache.off];
*size_ = lfs_min(
size,
lfs->pcache.size - (off-lfs->pcache.off));
return 0;
}
// flush pcache?
int err = lfsr_bd_flush(lfs, cksum, align);
if (err) {
return err;
}
}
// move the pcache, above conditions can no longer fail
lfs->pcache.block = block;
lfs->pcache.off = lfs_aligndown(off, lfs->cfg->prog_size);
lfs->pcache.size = lfs_min(
(off-lfs->pcache.off) + size,
lfs->cfg->pcache_size);
// zero to avoid any information leaks
lfs_memset(lfs->pcache.buffer, 0xff, lfs->cfg->pcache_size);
}
}
// caching prog
//
// with optional checksum
static int lfsr_bd_prog(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
const void *buffer, lfs_size_t size,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t off_ = off;
const uint8_t *buffer_ = buffer;
lfs_size_t size_ = size;
while (size_ > 0) {
// active pcache?
if (lfs->pcache.block == block
&& lfs->pcache.size != 0) {
// fits in pcache?
if (off_ < lfs->pcache.off + lfs->cfg->pcache_size) {
// you can't prog backwards silly
LFS_ASSERT(off_ >= lfs->pcache.off);
// expand the pcache?
lfs->pcache.size = lfs_min(
(off_-lfs->pcache.off) + size_,
lfs->cfg->pcache_size);
lfs_size_t d = lfs_min(
size_,
lfs->pcache.size - (off_-lfs->pcache.off));
lfs_memcpy(&lfs->pcache.buffer[off_-lfs->pcache.off],
buffer_,
d);
off_ += d;
buffer_ += d;
size_ -= d;
continue;
}
// flush pcache?
//
// flush even if we're bypassing pcache, some devices don't
// support out-of-order progs in a block
int err = lfsr_bd_flush(lfs, cksum, align);
if (err) {
return err;
}
}
// bypass pcache?
if (off_ % lfs->cfg->prog_size == 0
&& size_ >= lfs->cfg->pcache_size) {
lfs_size_t d = lfs_aligndown(size_, lfs->cfg->prog_size);
int err = lfsr_bd_prog_(lfs, block, off_, buffer_, d,
cksum, align);
if (err) {
return err;
}
off_ += d;
buffer_ += d;
size_ -= d;
continue;
}
// move the pcache, above conditions can no longer fail
lfs->pcache.block = block;
lfs->pcache.off = lfs_aligndown(off_, lfs->cfg->prog_size);
lfs->pcache.size = lfs_min(
(off_-lfs->pcache.off) + size_,
lfs->cfg->pcache_size);
// zero to avoid any information leaks
lfs_memset(lfs->pcache.buffer, 0xff, lfs->cfg->pcache_size);
}
// optional checksum
if (cksum && !align) {
*cksum = lfs_crc32c(*cksum, buffer, size);
}
return 0;
}
static int lfsr_bd_sync(lfs_t *lfs) {
// make sure we flush any caches
int err = lfsr_bd_flush(lfs, NULL, false);
if (err) {
return err;
}
return lfsr_bd_sync__(lfs);
}
static int lfsr_bd_erase(lfs_t *lfs, lfs_block_t block) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
// invalidate any relevant caches
if (lfs->pcache.block == block) {
lfsr_bd_droppcache(lfs);
}
if (lfs->rcache.block == block) {
lfsr_bd_droprcache(lfs);
}
return lfsr_bd_erase__(lfs, block);
}
// other block device utils
static int lfsr_bd_cksum(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
lfs_size_t size,
uint32_t *cksum) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t off_ = off;
lfs_size_t hint_ = lfs_max(hint, size); // make sure hint >= size
lfs_size_t size_ = size;
while (size_ > 0) {
const uint8_t *buffer__;
lfs_size_t size__;
int err = lfsr_bd_readnext(lfs, block, off_, hint_, size_,
&buffer__, &size__);
if (err) {
return err;
}
*cksum = lfs_crc32c(*cksum, buffer__, size__);
off_ += size__;
hint_ -= size__;
size_ -= size__;
}
return 0;
}
static lfs_scmp_t lfsr_bd_cmp(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
const void *buffer, lfs_size_t size) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t off_ = off;
lfs_size_t hint_ = lfs_max(hint, size); // make sure hint >= size
const uint8_t *buffer_ = buffer;
lfs_size_t size_ = size;
while (size_ > 0) {
const uint8_t *buffer__;
lfs_size_t size__;
int err = lfsr_bd_readnext(lfs, block, off_, hint_, size_,
&buffer__, &size__);
if (err) {
return err;
}
int cmp = lfs_memcmp(buffer__, buffer_, size__);
if (cmp != 0) {
return (cmp < 0) ? LFS_CMP_LT : LFS_CMP_GT;
}
off_ += size__;
hint_ -= size__;
buffer_ += size__;
size_ -= size__;
}
return LFS_CMP_EQ;
}
static int lfsr_bd_cpy(lfs_t *lfs,
lfs_block_t dst_block, lfs_size_t dst_off,
lfs_block_t src_block, lfs_size_t src_off, lfs_size_t hint,
lfs_size_t size,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(dst_block < lfs->block_count);
LFS_ASSERT(dst_off+size <= lfs->cfg->block_size);
LFS_ASSERT(src_block < lfs->block_count);
LFS_ASSERT(src_off+size <= lfs->cfg->block_size);
lfs_size_t dst_off_ = dst_off;
lfs_size_t src_off_ = src_off;
lfs_size_t hint_ = lfs_max(hint, size); // make sure hint >= size
lfs_size_t size_ = size;
while (size_ > 0) {
// prefer the pcache here to avoid rcache conflicts with prog
// validation, if we're lucky we might even be able to avoid
// clobbering the rcache at all
uint8_t *buffer__;
lfs_size_t size__;
int err = lfsr_bd_prognext(lfs, dst_block, dst_off_, size_,
&buffer__, &size__,
cksum, align);
if (err) {
return err;
}
err = lfsr_bd_read(lfs, src_block, src_off_, hint_,
buffer__, size__);
if (err) {
return err;
}
// optional checksum
if (cksum && !align) {
*cksum = lfs_crc32c(*cksum, buffer__, size__);
}
dst_off_ += size__;
src_off_ += size__;
hint_ -= size__;
size_ -= size__;
}
return 0;
}
static int lfsr_bd_set(lfs_t *lfs, lfs_block_t block, lfs_size_t off,
uint8_t c, lfs_size_t size,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(off+size <= lfs->cfg->block_size);
lfs_size_t off_ = off;
lfs_size_t size_ = size;
while (size_ > 0) {
uint8_t *buffer__;
lfs_size_t size__;
int err = lfsr_bd_prognext(lfs, block, off_, size_,
&buffer__, &size__,
cksum, align);
if (err) {
return err;
}
lfs_memset(buffer__, c, size__);
// optional checksum
if (cksum && !align) {
*cksum = lfs_crc32c(*cksum, buffer__, size__);
}
off_ += size__;
size_ -= size__;
}
return 0;
}
// lfsr_ptail_t stuff
//
// ptail tracks the most recent trunk's parity so we can parity-check
// if it hasn't been written to disk yet
#ifdef LFS_CKMETAPARITY
#define LFSR_PTAIL_PARITY 0x80000000
#endif
#ifdef LFS_CKMETAPARITY
static inline bool lfsr_ptail_parity(const lfs_t *lfs) {
return lfs->ptail.off & LFSR_PTAIL_PARITY;
}
#endif
#ifdef LFS_CKMETAPARITY
static inline lfs_size_t lfsr_ptail_off(const lfs_t *lfs) {
return lfs->ptail.off & ~LFSR_PTAIL_PARITY;
}
#endif
// checked read helpers
#ifdef LFS_CKDATACKSUMREADS
static int lfsr_bd_ckprefix(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
lfs_size_t cksize, uint32_t cksum,
lfs_size_t *hint_,
uint32_t *cksum__) {
(void)cksum;
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(cksize <= lfs->cfg->block_size);
// make sure hint includes our prefix/suffix
lfs_size_t hint__ = lfs_max(
// watch out for overflow when hint=-1!
off + lfs_min(
hint,
lfs->cfg->block_size - off),
cksize);
// checksum any prefixed data
int err = lfsr_bd_cksum(lfs,
block, 0, hint__,
off,
cksum__);
if (err) {
return err;
}
// return adjusted hint, note we clamped this to a positive range
// earlier, otherwise we'd have real problems with hint=-1!
*hint_ = hint__ - off;
return 0;
}
#endif
#ifdef LFS_CKDATACKSUMREADS
static int lfsr_bd_cksuffix(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
lfs_size_t cksize, uint32_t cksum,
uint32_t cksum__) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(cksize <= lfs->cfg->block_size);
// checksum any suffixed data
int err = lfsr_bd_cksum(lfs,
block, off, hint,
cksize - off,
&cksum__);
if (err) {
return err;
}
// do checksums match?
if (cksum__ != cksum) {
LFS_ERROR("Found ckdatacksums mismatch "
"0x%"PRIx32".%"PRIx32" %"PRId32", "
"cksum %08"PRIx32" (!= %08"PRIx32")",
block, 0, cksize,
cksum__, cksum);
return LFS_ERR_CORRUPT;
}
return 0;
}
#endif
// checked read functions
#ifdef LFS_CKDATACKSUMREADS
// caching read with parity/checksum checks
//
// the main downside of checking reads is we need to read all data that
// contributes to the relevant parity/checksum, this may be
// significantly more than the data we actually end up using
//
static int lfsr_bd_readck(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
void *buffer, lfs_size_t size,
lfs_size_t cksize, uint32_t cksum) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(cksize <= lfs->cfg->block_size);
// read should fit in ck info
LFS_ASSERT(off+size <= cksize);
// checksum any prefixed data
uint32_t cksum__ = 0;
lfs_size_t hint_;
int err = lfsr_bd_ckprefix(lfs, block, off, hint,
cksize, cksum,
&hint_,
&cksum__);
if (err) {
return err;
}
// read and checksum the data we're interested in
err = lfsr_bd_read(lfs,
block, off, hint_,
buffer, size);
if (err) {
return err;
}
cksum__ = lfs_crc32c(cksum__, buffer, size);
// checksum any suffixed data and validate
err = lfsr_bd_cksuffix(lfs, block, off+size, hint_-size,
cksize, cksum,
cksum__);
if (err) {
return err;
}
return 0;
}
#endif
// these could probably be a bit better deduplicated with their
// unchecked counterparts, but we don't generally use both at the same
// time
//
// we'd also need to worry about early termination in lfsr_bd_cmp/cmpck
#ifdef LFS_CKDATACKSUMREADS
static lfs_scmp_t lfsr_bd_cmpck(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
const void *buffer, lfs_size_t size,
lfs_size_t cksize, uint32_t cksum) {
// must be in-bounds
LFS_ASSERT(block < lfs->block_count);
LFS_ASSERT(cksize <= lfs->cfg->block_size);
// read should fit in ck info
LFS_ASSERT(off+size <= cksize);
// checksum any prefixed data
uint32_t cksum__ = 0;
lfs_size_t hint_;
int err = lfsr_bd_ckprefix(lfs, block, off, hint,
cksize, cksum,
&hint_,
&cksum__);
if (err) {
return err;
}
// compare the data while simultaneously updating the checksum
lfs_size_t off_ = off;
lfs_size_t hint__ = hint_ - off;
const uint8_t *buffer_ = buffer;
lfs_size_t size_ = size;
int cmp = LFS_CMP_EQ;
while (size_ > 0) {
const uint8_t *buffer__;
lfs_size_t size__;
err = lfsr_bd_readnext(lfs, block, off_, hint__, size_,
&buffer__, &size__);
if (err) {
return err;
}
cksum__ = lfs_crc32c(cksum__, buffer__, size__);
if (cmp == LFS_CMP_EQ) {
int cmp_ = lfs_memcmp(buffer__, buffer_, size__);
if (cmp_ != 0) {
cmp = (cmp_ < 0) ? LFS_CMP_LT : LFS_CMP_GT;
}
}
off_ += size__;
hint__ -= size__;
buffer_ += size__;
size_ -= size__;
}
// checksum any suffixed data and validate
err = lfsr_bd_cksuffix(lfs, block, off+size, hint_-size,
cksize, cksum,
cksum__);
if (err) {
return err;
}
return cmp;
}
#endif
#ifdef LFS_CKDATACKSUMREADS
static int lfsr_bd_cpyck(lfs_t *lfs,
lfs_block_t dst_block, lfs_size_t dst_off,
lfs_block_t src_block, lfs_size_t src_off, lfs_size_t hint,
lfs_size_t size,
lfs_size_t src_cksize, uint32_t src_cksum,
uint32_t *cksum, bool align) {
// must be in-bounds
LFS_ASSERT(dst_block < lfs->block_count);
LFS_ASSERT(dst_off+size <= lfs->cfg->block_size);
LFS_ASSERT(src_block < lfs->block_count);
LFS_ASSERT(src_cksize <= lfs->cfg->block_size);
// read should fit in ck info
LFS_ASSERT(src_off+size <= src_cksize);
// checksum any prefixed data
uint32_t cksum__ = 0;
lfs_size_t hint_;
int err = lfsr_bd_ckprefix(lfs, src_block, src_off, hint,
src_cksize, src_cksum,
&hint_,
&cksum__);
if (err) {
return err;
}
// copy the data while simultaneously updating our checksum
lfs_size_t dst_off_ = dst_off;
lfs_size_t src_off_ = src_off;
lfs_size_t hint__ = hint_;
lfs_size_t size_ = size;
while (size_ > 0) {
// prefer the pcache here to avoid rcache conflicts with prog
// validation, if we're lucky we might even be able to avoid
// clobbering the rcache at all
uint8_t *buffer__;
lfs_size_t size__;
err = lfsr_bd_prognext(lfs, dst_block, dst_off_, size_,
&buffer__, &size__,
cksum, align);
if (err) {
return err;
}
err = lfsr_bd_read(lfs, src_block, src_off_, hint__,
buffer__, size__);
if (err) {
return err;
}
// validating checksum
cksum__ = lfs_crc32c(cksum__, buffer__, size__);
// optional prog checksum
if (cksum && !align) {
*cksum = lfs_crc32c(*cksum, buffer__, size__);
}
dst_off_ += size__;
src_off_ += size__;
hint__ -= size__;
size_ -= size__;
}
// checksum any suffixed data and validate
err = lfsr_bd_cksuffix(lfs, src_block, src_off+size, hint_-size,
src_cksize, src_cksum,
cksum__);
if (err) {
return err;
}
return 0;
}
#endif
/// lfsr_tag_t stuff ///
// 16-bit metadata tags
enum lfsr_tag {
// the null tag is reserved
LFSR_TAG_NULL = 0x0000,
// config tags
LFSR_TAG_CONFIG = 0x0000,
LFSR_TAG_MAGIC = 0x0031,
LFSR_TAG_VERSION = 0x0034,
LFSR_TAG_RCOMPAT = 0x0035,
LFSR_TAG_WCOMPAT = 0x0036,
LFSR_TAG_OCOMPAT = 0x0037,
LFSR_TAG_GEOMETRY = 0x0038,
LFSR_TAG_NAMELIMIT = 0x0039,
LFSR_TAG_FILELIMIT = 0x003a,
// in-device only, to help find unknown config tags
LFSR_TAG_UNKNOWNCONFIG = 0x003b,
// global-state tags
LFSR_TAG_GDELTA = 0x0100,
LFSR_TAG_GRMDELTA = 0x0100,
// name tags
LFSR_TAG_NAME = 0x0200,
LFSR_TAG_BNAME = 0x0200,
LFSR_TAG_REG = 0x0201,
LFSR_TAG_DIR = 0x0202,
LFSR_TAG_STICKYNOTE = 0x0203,
LFSR_TAG_BOOKMARK = 0x0204,
// in-device only name tags, these should never get written to disk
LFSR_TAG_ORPHAN = 0x0205,
LFSR_TAG_TRAVERSAL = 0x0206,
LFSR_TAG_UNKNOWN = 0x0207,
// non-file name tags
LFSR_TAG_MNAME = 0x0220,
// struct tags
LFSR_TAG_STRUCT = 0x0300,
LFSR_TAG_BRANCH = 0x0300,
LFSR_TAG_DATA = 0x0304,
LFSR_TAG_BLOCK = 0x0308,
LFSR_TAG_DID = 0x0314,
LFSR_TAG_BSHRUB = 0x0318,
LFSR_TAG_BTREE = 0x031c,
LFSR_TAG_MROOT = 0x0321,
LFSR_TAG_MDIR = 0x0325,
LFSR_TAG_MTREE = 0x032c,
// user/sys attributes
LFSR_TAG_ATTR = 0x0400,
LFSR_TAG_UATTR = 0x0400,
LFSR_TAG_SATTR = 0x0500,
// shrub tags belong to secondary trees
LFSR_TAG_SHRUB = 0x1000,
// alt pointers form the inner nodes of our rbyd trees
LFSR_TAG_ALT = 0x4000,
LFSR_TAG_B = 0x0000,
LFSR_TAG_R = 0x2000,
LFSR_TAG_LE = 0x0000,
LFSR_TAG_GT = 0x1000,
// checksum tags
LFSR_TAG_CKSUM = 0x3000,
LFSR_TAG_PHASE = 0x0003,
LFSR_TAG_PERTURB = 0x0004,
LFSR_TAG_NOTE = 0x3100,
LFSR_TAG_ECKSUM = 0x3200,
LFSR_TAG_GCKSUMDELTA = 0x3300,
// in-device only tags, these should never get written to disk
LFSR_TAG_INTERNAL = 0x0800,
LFSR_TAG_RATTRS = 0x0800,
LFSR_TAG_SHRUBCOMMIT = 0x0801,
LFSR_TAG_GRMPUSH = 0x0802,
LFSR_TAG_MOVE = 0x0803,
LFSR_TAG_ATTRS = 0x0804,
// some in-device only tag modifiers
LFSR_TAG_RM = 0x8000,
LFSR_TAG_GROW = 0x4000,
LFSR_TAG_MASK0 = 0x0000,
LFSR_TAG_MASK2 = 0x1000,
LFSR_TAG_MASK8 = 0x2000,
LFSR_TAG_MASK12 = 0x3000,
};
// some other tag encodings with their own subfields
#define LFSR_TAG_ALT(c, d, key) \
(LFSR_TAG_ALT \
| (0x2000 & (c)) \
| (0x1000 & (d)) \
| (0x0fff & (lfsr_tag_t)(key)))
#define LFSR_TAG_ATTR(attr) \
(LFSR_TAG_ATTR \
| ((0x80 & (lfsr_tag_t)(attr)) << 1) \
| (0x7f & (lfsr_tag_t)(attr)))
// tag type operations
static inline lfsr_tag_t lfsr_tag_mode(lfsr_tag_t tag) {
return tag & 0xf000;
}
static inline lfsr_tag_t lfsr_tag_suptype(lfsr_tag_t tag) {
return tag & 0xff00;
}
static inline uint8_t lfsr_tag_subtype(lfsr_tag_t tag) {
return tag & 0x00ff;
}
static inline lfsr_tag_t lfsr_tag_key(lfsr_tag_t tag) {
return tag & 0x0fff;
}
static inline lfsr_tag_t lfsr_tag_supkey(lfsr_tag_t tag) {
return tag & 0x0f00;
}
static inline lfsr_tag_t lfsr_tag_subkey(lfsr_tag_t tag) {
return tag & 0x00ff;
}
static inline uint8_t lfsr_tag_redund(lfsr_tag_t tag) {
return tag & 0x0003;
}
static inline bool lfsr_tag_isalt(lfsr_tag_t tag) {
return tag & LFSR_TAG_ALT;
}
static inline bool lfsr_tag_isshrub(lfsr_tag_t tag) {
return tag & LFSR_TAG_SHRUB;
}
static inline bool lfsr_tag_istrunk(lfsr_tag_t tag) {
return lfsr_tag_mode(tag) != LFSR_TAG_CKSUM;
}
static inline uint8_t lfsr_tag_phase(lfsr_tag_t tag) {
return tag & LFSR_TAG_PHASE;
}
static inline bool lfsr_tag_perturb(lfsr_tag_t tag) {
return tag & LFSR_TAG_PERTURB;
}
static inline bool lfsr_tag_isinternal(lfsr_tag_t tag) {
return tag & LFSR_TAG_INTERNAL;
}
static inline bool lfsr_tag_isrm(lfsr_tag_t tag) {
return tag & LFSR_TAG_RM;
}
static inline bool lfsr_tag_isgrow(lfsr_tag_t tag) {
return tag & LFSR_TAG_GROW;
}
static inline bool lfsr_tag_ismask0(lfsr_tag_t tag) {
return ((tag >> 12) & 0x3) == 0;
}
static inline bool lfsr_tag_ismask2(lfsr_tag_t tag) {
return ((tag >> 12) & 0x3) == 1;
}
static inline bool lfsr_tag_ismask8(lfsr_tag_t tag) {
return ((tag >> 12) & 0x3) == 2;
}
static inline bool lfsr_tag_ismask12(lfsr_tag_t tag) {
return ((tag >> 12) & 0x3) == 3;
}
static inline lfsr_tag_t lfsr_tag_mask(lfsr_tag_t tag) {
return 0x0fff & (-1U << ((0xc820 >> (4*((tag >> 12) & 0x3))) & 0xf));
}
// alt operations
static inline bool lfsr_tag_isblack(lfsr_tag_t tag) {
return !(tag & LFSR_TAG_R);
}
static inline bool lfsr_tag_isred(lfsr_tag_t tag) {
return tag & LFSR_TAG_R;
}
static inline bool lfsr_tag_isle(lfsr_tag_t tag) {
return !(tag & LFSR_TAG_GT);
}
static inline bool lfsr_tag_isgt(lfsr_tag_t tag) {
return tag & LFSR_TAG_GT;
}
static inline lfsr_tag_t lfsr_tag_isparallel(lfsr_tag_t a, lfsr_tag_t b) {
return (a & LFSR_TAG_GT) == (b & LFSR_TAG_GT);
}
static inline bool lfsr_tag_follow(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_srid_t rid, lfsr_tag_t tag) {
// null tags break the following logic for unreachable alts
LFS_ASSERT(lfsr_tag_key(tag) != 0);
if (lfsr_tag_isgt(alt)) {
return rid > upper_rid - (lfsr_srid_t)weight - 1
|| (rid == upper_rid - (lfsr_srid_t)weight - 1
&& lfsr_tag_key(tag) > lfsr_tag_key(alt));
} else {
return rid < lower_rid + (lfsr_srid_t)weight - 1
|| (rid == lower_rid + (lfsr_srid_t)weight - 1
&& lfsr_tag_key(tag) <= lfsr_tag_key(alt));
}
}
static inline bool lfsr_tag_follow2(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_tag_t alt2, lfsr_rid_t weight2,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_srid_t rid, lfsr_tag_t tag) {
if (lfsr_tag_isred(alt2) && lfsr_tag_isparallel(alt, alt2)) {
weight += weight2;
}
return lfsr_tag_follow(alt, weight, lower_rid, upper_rid, rid, tag);
}
static inline void lfsr_tag_flip(
lfsr_tag_t *alt, lfsr_rid_t *weight,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid) {
*alt = *alt ^ LFSR_TAG_GT;
*weight = (upper_rid - lower_rid) - *weight;
}
static inline void lfsr_tag_flip2(
lfsr_tag_t *alt, lfsr_rid_t *weight,
lfsr_tag_t alt2, lfsr_rid_t weight2,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid) {
if (lfsr_tag_isred(alt2)) {
*weight += weight2;
}
lfsr_tag_flip(alt, weight, lower_rid, upper_rid);
}
static inline void lfsr_tag_trim(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_srid_t *lower_rid, lfsr_srid_t *upper_rid,
lfsr_tag_t *lower_tag, lfsr_tag_t *upper_tag) {
LFS_ASSERT((lfsr_srid_t)weight >= 0);
if (lfsr_tag_isgt(alt)) {
*upper_rid -= weight;
if (upper_tag) {
*upper_tag = alt + 1;
}
} else {
*lower_rid += weight;
if (lower_tag) {
*lower_tag = alt;
}
}
}
static inline void lfsr_tag_trim2(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_tag_t alt2, lfsr_rid_t weight2,
lfsr_srid_t *lower_rid, lfsr_srid_t *upper_rid,
lfsr_tag_t *lower_tag, lfsr_tag_t *upper_tag) {
if (lfsr_tag_isred(alt2)) {
lfsr_tag_trim(
alt2, weight2,
lower_rid, upper_rid,
lower_tag, upper_tag);
}
lfsr_tag_trim(
alt, weight,
lower_rid, upper_rid,
lower_tag, upper_tag);
}
static inline bool lfsr_tag_unreachable(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_tag_t lower_tag, lfsr_tag_t upper_tag) {
if (lfsr_tag_isgt(alt)) {
return !lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
upper_rid-1, upper_tag-1);
} else {
return !lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
lower_rid-1, lower_tag+1);
}
}
static inline bool lfsr_tag_unreachable2(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_tag_t alt2, lfsr_rid_t weight2,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_tag_t lower_tag, lfsr_tag_t upper_tag) {
if (lfsr_tag_isred(alt2)) {
lfsr_tag_trim(
alt2, weight2,
&lower_rid, &upper_rid,
&lower_tag, &upper_tag);
}
return lfsr_tag_unreachable(
alt, weight,
lower_rid, upper_rid,
lower_tag, upper_tag);
}
static inline bool lfsr_tag_diverging(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_srid_t a_rid, lfsr_tag_t a_tag,
lfsr_srid_t b_rid, lfsr_tag_t b_tag) {
return lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
a_rid, a_tag)
!= lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
b_rid, b_tag);
}
static inline bool lfsr_tag_diverging2(
lfsr_tag_t alt, lfsr_rid_t weight,
lfsr_tag_t alt2, lfsr_rid_t weight2,
lfsr_srid_t lower_rid, lfsr_srid_t upper_rid,
lfsr_srid_t a_rid, lfsr_tag_t a_tag,
lfsr_srid_t b_rid, lfsr_tag_t b_tag) {
return lfsr_tag_follow2(
alt, weight,
alt2, weight2,
lower_rid, upper_rid,
a_rid, a_tag)
!= lfsr_tag_follow2(
alt, weight,
alt2, weight2,
lower_rid, upper_rid,
b_rid, b_tag);
}
// support for encoding/decoding tags on disk
// tag encoding:
// .---+---+---+- -+- -+- -+- -+---+- -+- -+- -. tag: 1 be16 2 bytes
// | tag | weight | size | weight: 1 leb128 <=5 bytes
// '---+---+---+- -+- -+- -+- -+---+- -+- -+- -' size: 1 leb128 <=4 bytes
// total: <=11 bytes
#define LFSR_TAG_DSIZE (2+5+4)
// needed in lfsr_bd_readtag
#ifdef LFS_CKMETAPARITY
static inline bool lfsr_m_isckparity(uint32_t flags);
#endif
static lfs_ssize_t lfsr_bd_readtag(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfs_size_t hint,
lfsr_tag_t *tag_, lfsr_rid_t *weight_, lfs_size_t *size_,
uint32_t *cksum) {
// read the largest possible tag size
uint8_t tag_buf[LFSR_TAG_DSIZE];
lfs_size_t tag_dsize = lfs_min(LFSR_TAG_DSIZE, lfs->cfg->block_size-off);
if (tag_dsize < 4) {
return LFS_ERR_CORRUPT;
}
int err = lfsr_bd_read(lfs, block, off, hint,
tag_buf, tag_dsize);
if (err < 0) {
return err;
}
// check the valid bit?
if (cksum) {
// on-disk, the tag's valid bit must reflect the parity of the
// preceding data
//
// fortunately crc32cs are parity-preserving, so this is the
// same as the parity of the checksum
if ((tag_buf[0] >> 7) != lfs_parity(*cksum)) {
return LFS_ERR_CORRUPT;
}
}
lfsr_tag_t tag
= ((lfsr_tag_t)tag_buf[0] << 8)
| ((lfsr_tag_t)tag_buf[1] << 0);
lfs_ssize_t d = 2;
lfsr_rid_t weight;
lfs_ssize_t d_ = lfs_fromleb128(&weight, &tag_buf[d], tag_dsize-d);
if (d_ < 0) {
return d_;
}
// weights should be limited to 31-bits
if (weight > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
d += d_;
lfs_size_t size;
d_ = lfs_fromleb128(&size, &tag_buf[d], tag_dsize-d);
if (d_ < 0) {
return d_;
}
// sizes should be limited to 28-bits
if (size > 0x0fffffff) {
return LFS_ERR_CORRUPT;
}
d += d_;
// check our tag does not go out of bounds
if (!lfsr_tag_isalt(tag) && off+d + size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT;
}
#ifdef LFS_CKMETAPARITY
// check the parity if we're checking parity
//
// this requires reading all of the data as well, but with any luck
// the data will stick around in the cache
if (lfsr_m_isckparity(lfs->flags)
// don't bother checking parity if we're already calculating
// a checksum
&& !cksum) {
// checksum the tag, including our valid bit
uint32_t cksum_ = lfs_crc32c(0, tag_buf, d);
// checksum the data, if we have any
lfs_size_t hint_ = hint - lfs_min(d, hint);
lfs_size_t d_ = d;
if (!lfsr_tag_isalt(tag)) {
err = lfsr_bd_cksum(lfs,
// make sure hint includes our pesky parity byte
block, off+d_, lfs_max(hint_, size+1),
size,
&cksum_);
if (err) {
return err;
}
hint_ -= lfs_min(size, hint_);
d_ += size;
}
// pesky parity byte
if (off+d_ > lfs->cfg->block_size-1) {
return LFS_ERR_CORRUPT;
}
// read the pesky parity byte
//
// _usually_, the byte following a tag contains the tag's parity
//
// unless we're in the middle of building a commit, where things get
// tricky... to avoid problems with not-yet-written parity bits
// ptail tracks the most recent trunk's parity
//
// parity in in ptail?
bool parity;
if (block == lfs->ptail.block && off+d_ == lfsr_ptail_off(lfs)) {
parity = lfsr_ptail_parity(lfs);
// parity on disk?
} else {
uint8_t p;
err = lfsr_bd_read(lfs, block, off+d_, hint_,
&p, 1);
if (err) {
return err;
}
parity = p >> 7;
}
// does parity match?
if (lfs_parity(cksum_) != parity) {
LFS_ERROR("Found ckparity mismatch "
"0x%"PRIx32".%"PRIx32" %"PRId32", "
"parity %01"PRIx32" (!= %01"PRIx32")",
block, off, d_,
lfs_parity(cksum_), parity);
return LFS_ERR_CORRUPT;
}
}
#endif
// optional checksum
if (cksum) {
// exclude valid bit from checksum
*cksum ^= tag_buf[0] & 0x00000080;
// calculate checksum
*cksum = lfs_crc32c(*cksum, tag_buf, d);
}
// save what we found, clearing the valid bit, we don't need it
// anymore
*tag_ = tag & 0x7fff;
*weight_ = weight;
*size_ = size;
return d;
}
static lfs_ssize_t lfsr_bd_progtag(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, bool perturb,
lfsr_tag_t tag, lfsr_rid_t weight, lfs_size_t size,
uint32_t *cksum, bool align) {
// we set the valid bit here
LFS_ASSERT(!(tag & 0x8000));
// bit 7 is reserved for future subtype extensions
LFS_ASSERT(!(tag & 0x80));
// weight should not exceed 31-bits
LFS_ASSERT(weight <= 0x7fffffff);
// size should not exceed 28-bits
LFS_ASSERT(size <= 0x0fffffff);
// set the valid bit to the parity of the current checksum, inverted
// if the perturb bit is set, and exclude from the next checksum
LFS_ASSERT(cksum);
bool v = lfs_parity(*cksum) ^ perturb;
tag |= (lfsr_tag_t)v << 15;
*cksum ^= (uint32_t)v << 7;
// encode into a be16 and pair of leb128s
uint8_t tag_buf[LFSR_TAG_DSIZE];
tag_buf[0] = (uint8_t)(tag >> 8);
tag_buf[1] = (uint8_t)(tag >> 0);
lfs_ssize_t d = 2;
lfs_ssize_t d_ = lfs_toleb128(weight, &tag_buf[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfs_toleb128(size, &tag_buf[d], 4);
if (d_ < 0) {
return d_;
}
d += d_;
int err = lfsr_bd_prog(lfs, block, off, tag_buf, d,
cksum, align);
if (err < 0) {
return err;
}
return d;
}
/// lfsr_data_t stuff ///
#define LFSR_DATA_ONDISK 0x80000000
#define LFSR_DATA_ISBPTR 0x40000000
#ifdef LFS_CKDATACKSUMREADS
#define LFSR_DATA_ISERASED 0x80000000
#endif
#define LFSR_DATA_NULL() \
((lfsr_data_t){ \
.size=0, \
.u.buffer=NULL})
#define LFSR_DATA_BUF(_buffer, _size) \
((lfsr_data_t){ \
.size=_size, \
.u.buffer=(const void*)(_buffer)})
#define LFSR_DATA_DISK(_block, _off, _size) \
((lfsr_data_t){ \
.size=LFSR_DATA_ONDISK | (_size), \
.u.disk.block=_block, \
.u.disk.off=_off})
// data helpers
static inline bool lfsr_data_ondisk(lfsr_data_t data) {
return data.size & LFSR_DATA_ONDISK;
}
static inline bool lfsr_data_isbuf(lfsr_data_t data) {
return !(data.size & LFSR_DATA_ONDISK);
}
static inline bool lfsr_data_isbptr(lfsr_data_t data) {
return data.size & LFSR_DATA_ISBPTR;
}
static inline lfs_size_t lfsr_data_size(lfsr_data_t data) {
return data.size & ~LFSR_DATA_ONDISK & ~LFSR_DATA_ISBPTR;
}
#ifdef LFS_CKDATACKSUMREADS
static inline lfs_size_t lfsr_data_cksize(lfsr_data_t data) {
return data.u.disk.cksize & ~LFSR_DATA_ISERASED;
}
#endif
#ifdef LFS_CKDATACKSUMREADS
static inline uint32_t lfsr_data_cksum(lfsr_data_t data) {
return data.u.disk.cksum;
}
#endif
// data slicing
#define LFSR_DATA_SLICE(_data, _off, _size) \
((struct {lfsr_data_t d;}){lfsr_data_fromslice(_data, _off, _size)}.d)
LFS_FORCEINLINE
static inline lfsr_data_t lfsr_data_fromslice(lfsr_data_t data,
lfs_ssize_t off, lfs_ssize_t size) {
// limit our off/size to data range, note the use of unsigned casts
// here to treat -1 as unbounded
lfs_size_t off_ = lfs_min(
lfs_smax(off, 0),
lfsr_data_size(data));
lfs_size_t size_ = lfs_min(
(lfs_size_t)size,
lfsr_data_size(data) - off_);
// on-disk?
if (lfsr_data_ondisk(data)) {
data.u.disk.off += off_;
data.size -= lfsr_data_size(data) - size_;
// buffer?
} else {
data.u.buffer += off_;
data.size -= lfsr_data_size(data) - size_;
}
return data;
}
#define LFSR_DATA_TRUNCATE(_data, _size) \
((struct {lfsr_data_t d;}){lfsr_data_fromtruncate(_data, _size)}.d)
LFS_FORCEINLINE
static inline lfsr_data_t lfsr_data_fromtruncate(lfsr_data_t data,
lfs_size_t size) {
return LFSR_DATA_SLICE(data, -1, size);
}
#define LFSR_DATA_FRUNCATE(_data, _size) \
((struct {lfsr_data_t d;}){lfsr_data_fromfruncate(_data, _size)}.d)
LFS_FORCEINLINE
static inline lfsr_data_t lfsr_data_fromfruncate(lfsr_data_t data,
lfs_size_t size) {
return LFSR_DATA_SLICE(data,
lfsr_data_size(data) - lfs_min(
size,
lfsr_data_size(data)),
-1);
}
// data <-> bd interactions
// lfsr_data_read* operations update the lfsr_data_t, effectively
// consuming the data
// needed in lfsr_data_read and friends
#ifdef LFS_CKDATACKSUMREADS
static inline bool lfsr_m_isckdatacksums(uint32_t flags);
#endif
static lfs_ssize_t lfsr_data_read(lfs_t *lfs, lfsr_data_t *data,
void *buffer, lfs_size_t size) {
// limit our size to data range
lfs_size_t d = lfs_min(size, lfsr_data_size(*data));
// on-disk?
if (lfsr_data_ondisk(*data)) {
// validating data cksums?
if (LFS_IFDEF_CKDATACKSUMREADS(
lfsr_m_isckdatacksums(lfs->flags)
&& lfsr_data_isbptr(*data),
false)) {
#ifdef LFS_CKDATACKSUMREADS
int err = lfsr_bd_readck(lfs,
data->u.disk.block, data->u.disk.off,
// note our hint includes the full data range
lfsr_data_size(*data),
buffer, d,
lfsr_data_cksize(*data), lfsr_data_cksum(*data));
if (err < 0) {
return err;
}
#endif
} else {
int err = lfsr_bd_read(lfs,
data->u.disk.block, data->u.disk.off,
// note our hint includes the full data range
lfsr_data_size(*data),
buffer, d);
if (err < 0) {
return err;
}
}
// buffer?
} else {
lfs_memcpy(buffer, data->u.buffer, d);
}
*data = LFSR_DATA_SLICE(*data, d, -1);
return d;
}
static int lfsr_data_readle32(lfs_t *lfs, lfsr_data_t *data,
uint32_t *word) {
uint8_t buf[4];
lfs_ssize_t d = lfsr_data_read(lfs, data, buf, 4);
if (d < 0) {
return d;
}
// truncated?
if (d < 4) {
return LFS_ERR_CORRUPT;
}
*word = lfs_fromle32(buf);
return 0;
}
// note all leb128s in our system reserve the sign bit
static int lfsr_data_readleb128(lfs_t *lfs, lfsr_data_t *data,
uint32_t *word_) {
// note we make sure not to update our data offset until after leb128
// decoding
lfsr_data_t data_ = *data;
// for 32-bits we can assume worst-case leb128 size is 5-bytes
uint8_t buf[5];
lfs_ssize_t d = lfsr_data_read(lfs, &data_, buf, 5);
if (d < 0) {
return d;
}
d = lfs_fromleb128(word_, buf, d);
if (d < 0) {
return d;
}
// all leb128s in our system reserve the sign bit
if (*word_ > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
*data = LFSR_DATA_SLICE(*data, d, -1);
return 0;
}
// a little-leb128 in our system is truncated to align nicely
//
// for 32-bit words, little-leb128s are truncated to 28-bits, so the
// resulting leb128 encoding fits nicely in 4-bytes
static inline int lfsr_data_readlleb128(lfs_t *lfs, lfsr_data_t *data,
uint32_t *word_) {
// just call readleb128 here
int err = lfsr_data_readleb128(lfs, data, word_);
if (err) {
return err;
}
// little-leb128s should be limited to 28-bits
if (*word_ > 0x0fffffff) {
return LFS_ERR_CORRUPT;
}
return 0;
}
static lfs_scmp_t lfsr_data_cmp(lfs_t *lfs, lfsr_data_t data,
const void *buffer, lfs_size_t size) {
// compare common prefix
lfs_size_t d = lfs_min(size, lfsr_data_size(data));
// on-disk?
if (lfsr_data_ondisk(data)) {
// validating data cksums?
if (LFS_IFDEF_CKDATACKSUMREADS(
lfsr_m_isckdatacksums(lfs->flags)
&& lfsr_data_isbptr(data),
false)) {
#ifdef LFS_CKDATACKSUMREADS
int cmp = lfsr_bd_cmpck(lfs,
// note the 0 hint, we don't usually use any
// following data
data.u.disk.block, data.u.disk.off, 0,
buffer, d,
lfsr_data_cksize(data), lfsr_data_cksum(data));
if (cmp != LFS_CMP_EQ) {
return cmp;
}
#endif
} else {
int cmp = lfsr_bd_cmp(lfs,
// note the 0 hint, we don't usually use any
// following data
data.u.disk.block, data.u.disk.off, 0,
buffer, d);
if (cmp != LFS_CMP_EQ) {
return cmp;
}
}
// buffer?
} else {
int cmp = lfs_memcmp(data.u.buffer, buffer, d);
if (cmp < 0) {
return LFS_CMP_LT;
} else if (cmp > 0) {
return LFS_CMP_GT;
}
}
// if data is equal, check for size mismatch
if (lfsr_data_size(data) < size) {
return LFS_CMP_LT;
} else if (lfsr_data_size(data) > size) {
return LFS_CMP_GT;
} else {
return LFS_CMP_EQ;
}
}
static lfs_scmp_t lfsr_data_namecmp(lfs_t *lfs, lfsr_data_t data,
lfsr_did_t did, const char *name, lfs_size_t name_len) {
// first compare the did
lfsr_did_t did_;
int err = lfsr_data_readleb128(lfs, &data, &did_);
if (err < 0) {
return err;
}
if (did_ < did) {
return LFS_CMP_LT;
} else if (did_ > did) {
return LFS_CMP_GT;
}
// then compare the actual name
return lfsr_data_cmp(lfs, data, name, name_len);
}
static int lfsr_bd_progdata(lfs_t *lfs,
lfs_block_t block, lfs_size_t off, lfsr_data_t data,
uint32_t *cksum, bool align) {
// on-disk?
if (lfsr_data_ondisk(data)) {
// validating data cksums?
if (LFS_IFDEF_CKDATACKSUMREADS(
lfsr_m_isckdatacksums(lfs->flags)
&& lfsr_data_isbptr(data),
false)) {
#ifdef LFS_CKDATACKSUMREADS
int err = lfsr_bd_cpyck(lfs, block, off,
data.u.disk.block, data.u.disk.off, lfsr_data_size(data),
lfsr_data_size(data),
lfsr_data_cksize(data), lfsr_data_cksum(data),
cksum, align);
if (err) {
return err;
}
#endif
} else {
int err = lfsr_bd_cpy(lfs, block, off,
data.u.disk.block, data.u.disk.off, lfsr_data_size(data),
lfsr_data_size(data),
cksum, align);
if (err) {
return err;
}
}
// buffer?
} else {
int err = lfsr_bd_prog(lfs, block, off,
data.u.buffer, data.size,
cksum, align);
if (err) {
return err;
}
}
return 0;
}
// macros for le32/leb128/lleb128 encoding, these are useful for
// building rattrs
// le32 encoding:
// .---+---+---+---. total: 1 le32 4 bytes
// | le32 |
// '---+---+---+---'
//
#define LFSR_LE32_DSIZE 4
static inline lfsr_data_t lfsr_data_fromle32(uint32_t word,
uint8_t buffer[static LFSR_LE32_DSIZE]) {
lfs_tole32(word, buffer);
return LFSR_DATA_BUF(buffer, LFSR_LE32_DSIZE);
}
// leb128 encoding:
// .---+- -+- -+- -+- -. total: 1 leb128 <=5 bytes
// | leb128 |
// '---+- -+- -+- -+- -'
//
#define LFSR_LEB128_DSIZE 5
static inline lfsr_data_t lfsr_data_fromleb128(uint32_t word,
uint8_t buffer[static LFSR_LEB128_DSIZE]) {
// leb128s should not exceed 31-bits
LFS_ASSERT(word <= 0x7fffffff);
lfs_ssize_t d = lfs_toleb128(word, buffer, LFSR_LEB128_DSIZE);
if (d < 0) {
LFS_UNREACHABLE();
}
return LFSR_DATA_BUF(buffer, d);
}
// lleb128 encoding:
// .---+- -+- -+- -. total: 1 leb128 <=4 bytes
// | lleb128 |
// '---+- -+- -+- -'
//
#define LFSR_LLEB128_DSIZE 4
static inline lfsr_data_t lfsr_data_fromlleb128(uint32_t word,
uint8_t buffer[static LFSR_LLEB128_DSIZE]) {
// little-leb128s should not exceed 28-bits
LFS_ASSERT(word <= 0x0fffffff);
lfs_ssize_t d = lfs_toleb128(word, buffer, LFSR_LLEB128_DSIZE);
if (d < 0) {
LFS_UNREACHABLE();
}
return LFSR_DATA_BUF(buffer, d);
}
// we need to at least define DSIZE/DATA macros here
// ecksum encoding:
// .---+- -+- -+- -. cksize: 1 leb128 <=4 bytes
// | cksize | cksum: 1 le32 4 bytes
// +---+- -+- -+- -+ total: <=8 bytes
// | cksum |
// '---+---+---+---'
//
#define LFSR_ECKSUM_DSIZE (4+4)
// branch encoding:
// .---+- -+- -+- -+- -. block: 1 leb128 <=5 bytes
// | block | trunk: 1 leb128 <=4 bytes
// +---+- -+- -+- -+- -' cksum: 1 le32 4 bytes
// | trunk | total: <=13 bytes
// +---+- -+- -+- -+
// | cksum |
// '---+---+---+---'
//
#define LFSR_BRANCH_DSIZE (5+4+4)
// btree encoding:
// .---+- -+- -+- -+- -. weight: 1 leb128 <=5 bytes
// | weight | block: 1 leb128 <=5 bytes
// +---+- -+- -+- -+- -+ trunk: 1 leb128 <=4 bytes
// | block | cksum: 1 le32 4 bytes
// +---+- -+- -+- -+- -' total: <=18 bytes
// | trunk |
// +---+- -+- -+- -+
// | cksum |
// '---+---+---+---'
//
#define LFSR_BTREE_DSIZE (5+LFSR_BRANCH_DSIZE)
// bptr encoding:
// .---+- -+- -+- -. size: 1 leb128 <=4 bytes
// | size | block: 1 leb128 <=5 bytes
// +---+- -+- -+- -+- -. off: 1 leb128 <=4 bytes
// | block | cksize: 1 leb128 <=4 bytes
// +---+- -+- -+- -+- -' cksum: 1 le32 4 bytes
// | off | total: <=21 bytes
// +---+- -+- -+- -+
// | cksize |
// +---+- -+- -+- -+
// | cksum |
// '---+---+---+---'
//
#define LFSR_BPTR_DSIZE (4+5+4+4+4)
// shrub encoding:
// .---+- -+- -+- -+- -. weight: 1 leb128 <=5 bytes
// | weight | trunk: 1 leb128 <=4 bytes
// +---+- -+- -+- -+- -' total: <=9 bytes
// | trunk |
// '---+- -+- -+- -'
//
#define LFSR_SHRUB_DSIZE (5+4)
// mptr encoding:
// .---+- -+- -+- -+- -. blocks: 2 leb128s <=2x5 bytes
// | block x 2 | total: <=10 bytes
// + +
// | |
// '---+- -+- -+- -+- -'
//
#define LFSR_MPTR_DSIZE (5+5)
// geometry encoding
// .---+- -+- -+- -. block_size: 1 leb128 <=4 bytes
// | block_size | block_count: 1 leb128 <=5 bytes
// +---+- -+- -+- -+- -. total: <=9 bytes
// | block_count |
// '---+- -+- -+- -+- -'
#define LFSR_GEOMETRY_DSIZE (4+5)
// operations on attribute lists
// our core attribute type
typedef struct lfsr_rattr {
lfsr_tag_t tag;
// ignoring lazy/special tags
// sign(count)=0 => in-RAM buffer or estimate for lazy tags
// sign(count)=1 => multiple concatenated datas
int16_t count;
lfsr_srid_t weight;
union {
const uint8_t *buffer;
const lfsr_data_t *datas;
uint32_t le32;
uint32_t leb128;
uint32_t lleb128;
const void *etc;
} u;
} lfsr_rattr_t;
// low-level attr macro
#define LFSR_RATTR_(_tag, _weight, _u, _count) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=_count, \
.weight=_weight, \
.u=_u})
// high-level attr macros
#define LFSR_RATTR(_tag, _weight) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.datas=NULL})
#define LFSR_RATTR_BUF(_tag, _weight, _buffer, _size) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=(uint16_t){_size}, \
.weight=_weight, \
.u.buffer=(const void*)(_buffer)})
#define LFSR_RATTR_DATA(_tag, _weight, _data) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=-1, \
.weight=_weight, \
.u.datas=_data})
#define LFSR_RATTR_CAT_(_tag, _weight, _datas, _data_count) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=-(uint16_t){_data_count}, \
.weight=_weight, \
.u.datas=_datas})
#define LFSR_RATTR_CAT(_tag, _weight, ...) \
LFSR_RATTR_CAT_( \
_tag, \
_weight, \
((const lfsr_data_t[]){__VA_ARGS__}), \
sizeof((const lfsr_data_t[]){__VA_ARGS__}) / sizeof(lfsr_data_t))
#define LFSR_RATTR_NOOP() \
((lfsr_rattr_t){ \
.tag=LFSR_TAG_NULL, \
.count=0, \
.weight=0, \
.u.buffer=NULL})
// as convenience we lazily encode single le32/leb128/lleb128 attrs
//
// this also avoids needing a stack allocation for these attrs
#define LFSR_RATTR_LE32(_tag, _weight, _le32) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.le32=_le32})
#define LFSR_RATTR_LEB128(_tag, _weight, _leb128) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.leb128=_leb128})
#define LFSR_RATTR_LLEB128(_tag, _weight, _lleb128) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.lleb128=_lleb128})
// helper macro for did + name pairs
typedef struct lfsr_name {
uint32_t did;
const char *name;
lfs_size_t name_len;
} lfsr_name_t;
#define LFSR_RATTR_NAME_(_tag, _weight, _name) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfsr_name_t*){_name}})
#define LFSR_RATTR_NAME(_tag, _weight, _did, _name, _name_len) \
LFSR_RATTR_NAME_( \
_tag, \
_weight, \
(&(const lfsr_name_t){ \
.did=_did, \
.name=_name, \
.name_len=_name_len}))
// macros for other lazily encoded attrs
#define LFSR_RATTR_GEOMETRY(_tag, _weight, _geometry) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfsr_geometry_t*){_geometry}})
// note the LFSR_BPTR_DSIZE hint so shrub estimates work
#define LFSR_RATTR_BPTR(_tag, _weight, _bptr) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=LFSR_BPTR_DSIZE, \
.weight=_weight, \
.u.etc=(const lfsr_bptr_t*){_bptr}})
#define LFSR_RATTR_SHRUB(_tag, _weight, _shrub) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfsr_shrub_t*){_shrub}})
#define LFSR_RATTR_BTREE(_tag, _weight, _btree) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfsr_btree_t*){_btree}})
#define LFSR_RATTR_MPTR(_tag, _weight, _mptr) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfs_block_t*){_mptr}})
#define LFSR_RATTR_ECKSUM(_tag, _weight, _ecksum) \
((lfsr_rattr_t){ \
.tag=_tag, \
.count=0, \
.weight=_weight, \
.u.etc=(const lfsr_ecksum_t*){_ecksum}})
// these are special attrs that trigger unique behavior in
// lfsr_mdir_commit__
#define LFSR_RATTR_RATTRS(_rattrs, _rattr_count) \
((lfsr_rattr_t){ \
.tag=LFSR_TAG_RATTRS, \
.count=(uint16_t){_rattr_count}, \
.weight=0, \
.u.etc=(const lfsr_rattr_t*){_rattrs}})
#define LFSR_RATTR_SHRUBCOMMIT(_shrubcommit) \
((lfsr_rattr_t){ \
.tag=LFSR_TAG_SHRUBCOMMIT, \
.count=0, \
.weight=0, \
.u.etc=(const lfsr_shrubcommit_t*){_shrubcommit}})
#define LFSR_RATTR_MOVE(_move) \
((lfsr_rattr_t){ \
.tag=LFSR_TAG_MOVE, \
.count=0, \
.weight=0, \
.u.etc=(const lfsr_mdir_t*){_move}})
#define LFSR_RATTR_ATTRS(_attrs, _attr_count) \
((lfsr_rattr_t){ \
.tag=LFSR_TAG_ATTRS, \
.count=(uint16_t){_attr_count}, \
.weight=0, \
.u.etc=(const struct lfs_attr*){_attrs}})
// create an attribute list
#define LFSR_RATTRS(...) \
(const lfsr_rattr_t[]){__VA_ARGS__}, \
sizeof((const lfsr_rattr_t[]){__VA_ARGS__}) / sizeof(lfsr_rattr_t)
// rattr helpers
static inline bool lfsr_rattr_isnoop(lfsr_rattr_t rattr) {
// noop rattrs must have zero weight
LFS_ASSERT(rattr.tag || rattr.weight == 0);
return !rattr.tag;
}
static inline bool lfsr_rattr_isinsert(lfsr_rattr_t rattr) {
return !lfsr_tag_isgrow(rattr.tag) && rattr.weight > 0;
}
static inline lfsr_srid_t lfsr_rattr_nextrid(lfsr_rattr_t rattr,
lfsr_srid_t rid) {
if (lfsr_rattr_isinsert(rattr)) {
return rid + rattr.weight-1;
} else {
return rid + rattr.weight;
}
}
static inline lfsr_tag_t lfsr_rattr_dtag(lfsr_rattr_t rattr) {
// lazily tag encoding can be bypassed with explicit data, this is
// necessary to allow copies during compaction, relocation, etc
if (rattr.count >= 0) {
return rattr.tag;
} else {
return LFSR_TAG_DATA;
}
}
static inline lfs_size_t lfsr_rattr_dsize(lfsr_rattr_t rattr) {
// note this does not include the tag size
//
// this gets a bit complicated for concatenated data
if (rattr.count >= 0) {
return rattr.count;
} else {
const lfsr_data_t *datas = rattr.u.datas;
lfs_size_t data_count = -rattr.count;
lfs_size_t size = 0;
for (lfs_size_t i = 0; i < data_count; i++) {
size += lfsr_data_size(datas[i]);
}
return size;
}
}
// operations on custom attribute lists
//
// a slightly different struct because it's user facing
static inline lfs_ssize_t lfsr_attr_size(const struct lfs_attr *attr) {
// we default to the buffer_size if a mutable size is not provided
if (attr->size) {
return *attr->size;
} else {
return attr->buffer_size;
}
}
static inline bool lfsr_attr_isnoattr(const struct lfs_attr *attr) {
return lfsr_attr_size(attr) == LFS_ERR_NOATTR;
}
static lfs_scmp_t lfsr_attr_cmp(lfs_t *lfs, const struct lfs_attr *attr,
const lfsr_data_t *data) {
// note data=NULL => NOATTR
if (!data) {
return (lfsr_attr_isnoattr(attr)) ? LFS_CMP_EQ : LFS_CMP_GT;
} else {
if (lfsr_attr_isnoattr(attr)) {
return LFS_CMP_LT;
} else {
return lfsr_data_cmp(lfs, *data,
attr->buffer,
lfsr_attr_size(attr));
}
}
}
// operations on erased-state checksums
// erased-state checksum
typedef struct lfsr_ecksum {
// cksize=-1 indicates no ecksum
lfs_ssize_t cksize;
uint32_t cksum;
} lfsr_ecksum_t;
// erased-state checksum on-disk encoding
static lfsr_data_t lfsr_data_fromecksum(const lfsr_ecksum_t *ecksum,
uint8_t buffer[static LFSR_ECKSUM_DSIZE]) {
// you shouldn't try to encode a not-ecksum, that doesn't make sense
LFS_ASSERT(ecksum->cksize != -1);
// cksize should not exceed 28-bits
LFS_ASSERT((lfs_size_t)ecksum->cksize <= 0x0fffffff);
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(ecksum->cksize, &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
lfs_tole32(ecksum->cksum, &buffer[d]);
d += 4;
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readecksum(lfs_t *lfs, lfsr_data_t *data,
lfsr_ecksum_t *ecksum) {
int err = lfsr_data_readlleb128(lfs, data, (lfs_size_t*)&ecksum->cksize);
if (err) {
return err;
}
err = lfsr_data_readle32(lfs, data, &ecksum->cksum);
if (err) {
return err;
}
return 0;
}
/// block pointer things ///
#define LFSR_BPTR_ONDISK LFSR_DATA_ONDISK
#define LFSR_BPTR_ISBPTR LFSR_DATA_ISBPTR
#define LFSR_BPTR_ISERASED 0x80000000
static void lfsr_bptr_init(lfsr_bptr_t *bptr,
lfsr_data_t data, lfs_size_t cksize, uint32_t cksum) {
// make sure the bptr flag is set
LFS_ASSERT(lfsr_data_ondisk(data));
bptr->data.size = data.size | LFSR_DATA_ONDISK | LFSR_BPTR_ISBPTR;
bptr->data.u.disk.block = data.u.disk.block;
bptr->data.u.disk.off = data.u.disk.off;
#ifdef LFS_CKDATACKSUMREADS
bptr->data.u.disk.cksize = cksize;
bptr->data.u.disk.cksum = cksum;
#else
bptr->cksize = cksize;
bptr->cksum = cksum;
#endif
}
static inline void lfsr_bptr_discard(lfsr_bptr_t *bptr) {
bptr->data = LFSR_DATA_NULL();
#ifndef LFS_CKDATACKSUMREADS
bptr->cksize = 0;
bptr->cksum = 0;
#endif
}
static inline void lfsr_bptr_claim(lfsr_bptr_t *bptr) {
#ifdef LFS_CKDATACKSUMREADS
bptr->data.u.disk.cksize &= ~LFSR_BPTR_ISERASED;
#else
bptr->cksize &= ~LFSR_BPTR_ISERASED;
#endif
}
static inline bool lfsr_bptr_isbptr(const lfsr_bptr_t *bptr) {
return bptr->data.size & LFSR_BPTR_ISBPTR;
}
static inline lfs_block_t lfsr_bptr_block(const lfsr_bptr_t *bptr) {
return bptr->data.u.disk.block;
}
static inline lfs_size_t lfsr_bptr_off(const lfsr_bptr_t *bptr) {
return bptr->data.u.disk.off;
}
static inline lfs_size_t lfsr_bptr_size(const lfsr_bptr_t *bptr) {
return bptr->data.size & ~LFSR_BPTR_ONDISK & ~LFSR_BPTR_ISBPTR;
}
// checked reads adds ck info to lfsr_data_t that we don't want to
// unnecessarily duplicate, this makes accessing ck info annoyingly
// messy...
static inline bool lfsr_bptr_iserased(const lfsr_bptr_t *bptr) {
#ifdef LFS_CKDATACKSUMREADS
return bptr->data.u.disk.cksize & LFSR_BPTR_ISERASED;
#else
return bptr->cksize & LFSR_BPTR_ISERASED;
#endif
}
static inline lfs_size_t lfsr_bptr_cksize(const lfsr_bptr_t *bptr) {
#ifdef LFS_CKDATACKSUMREADS
return bptr->data.u.disk.cksize & ~LFSR_BPTR_ISERASED;
#else
return bptr->cksize & ~LFSR_BPTR_ISERASED;
#endif
}
static inline uint32_t lfsr_bptr_cksum(const lfsr_bptr_t *bptr) {
#ifdef LFS_CKDATACKSUMREADS
return bptr->data.u.disk.cksum;
#else
return bptr->cksum;
#endif
}
// bptr on-disk encoding
static lfsr_data_t lfsr_data_frombptr(const lfsr_bptr_t *bptr,
uint8_t buffer[static LFSR_BPTR_DSIZE]) {
// size should not exceed 28-bits
LFS_ASSERT(lfsr_data_size(bptr->data) <= 0x0fffffff);
// block should not exceed 31-bits
LFS_ASSERT(lfsr_bptr_block(bptr) <= 0x7fffffff);
// off should not exceed 28-bits
LFS_ASSERT(lfsr_bptr_off(bptr) <= 0x0fffffff);
// cksize should not exceed 28-bits
LFS_ASSERT(lfsr_bptr_cksize(bptr) <= 0x0fffffff);
lfs_ssize_t d = 0;
// write the block, offset, size
lfs_ssize_t d_ = lfs_toleb128(lfsr_data_size(bptr->data), &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
d_ = lfs_toleb128(lfsr_bptr_block(bptr), &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
d_ = lfs_toleb128(lfsr_bptr_off(bptr), &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
// write the cksize, cksum
d_ = lfs_toleb128(lfsr_bptr_cksize(bptr), &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
lfs_tole32(lfsr_bptr_cksum(bptr), &buffer[d]);
d += 4;
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readbptr(lfs_t *lfs, lfsr_data_t *data,
lfsr_bptr_t *bptr) {
// read the block, offset, size
int err = lfsr_data_readlleb128(lfs, data, &bptr->data.size);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, data, &bptr->data.u.disk.block);
if (err) {
return err;
}
err = lfsr_data_readlleb128(lfs, data, &bptr->data.u.disk.off);
if (err) {
return err;
}
// read the cksize, cksum
err = lfsr_data_readlleb128(lfs, data,
LFS_IFDEF_CKDATACKSUMREADS(
&bptr->data.u.disk.cksize,
&bptr->cksize));
if (err) {
return err;
}
err = lfsr_data_readle32(lfs, data,
LFS_IFDEF_CKDATACKSUMREADS(
&bptr->data.u.disk.cksum,
&bptr->cksum));
if (err) {
return err;
}
// mark as on-disk + cksum
bptr->data.size |= LFSR_DATA_ONDISK | LFSR_DATA_ISBPTR;
return 0;
}
// check the contents of a bptr
static int lfsr_bptr_ck(lfs_t *lfs, const lfsr_bptr_t *bptr) {
uint32_t cksum = 0;
int err = lfsr_bd_cksum(lfs,
lfsr_bptr_block(bptr), 0, 0,
lfsr_bptr_cksize(bptr),
&cksum);
if (err) {
return err;
}
// test that our cksum matches what's expected
if (cksum != lfsr_bptr_cksum(bptr)) {
LFS_ERROR("Found bptr cksum mismatch "
"0x%"PRIx32".%"PRIx32" %"PRId32", "
"cksum %08"PRIx32" (!= %08"PRIx32")",
lfsr_bptr_block(bptr), 0,
lfsr_bptr_cksize(bptr),
cksum, lfsr_bptr_cksum(bptr));
return LFS_ERR_CORRUPT;
}
return 0;
}
/// Red-black-yellow Dhara tree operations ///
#define LFSR_RBYD_ISSHRUB 0x80000000
#define LFSR_RBYD_ISPERTURB 0x80000000
// helper functions
static void lfsr_rbyd_init(lfsr_rbyd_t *rbyd, lfs_block_t block) {
rbyd->blocks[0] = block;
rbyd->trunk = 0;
rbyd->weight = 0;
rbyd->eoff = 0;
rbyd->cksum = 0;
}
static inline void lfsr_rbyd_claim(lfsr_rbyd_t *rbyd) {
rbyd->eoff = -1;
}
static inline bool lfsr_rbyd_isshrub(const lfsr_rbyd_t *rbyd) {
return rbyd->trunk & LFSR_RBYD_ISSHRUB;
}
static inline lfs_size_t lfsr_rbyd_trunk(const lfsr_rbyd_t *rbyd) {
return rbyd->trunk & ~LFSR_RBYD_ISSHRUB;
}
static inline bool lfsr_rbyd_isfetched(const lfsr_rbyd_t *rbyd) {
return !lfsr_rbyd_trunk(rbyd) || rbyd->eoff;
}
static inline bool lfsr_rbyd_isperturb(const lfsr_rbyd_t *rbyd) {
return rbyd->eoff & LFSR_RBYD_ISPERTURB;
}
static inline lfs_size_t lfsr_rbyd_eoff(const lfsr_rbyd_t *rbyd) {
return rbyd->eoff & ~LFSR_RBYD_ISPERTURB;
}
static inline int lfsr_rbyd_cmp(
const lfsr_rbyd_t *a,
const lfsr_rbyd_t *b) {
if (a->blocks[0] != b->blocks[0]) {
return a->blocks[0] - b->blocks[0];
} else {
return a->trunk - b->trunk;
}
}
// needed in lfsr_rbyd_alloc
static lfs_sblock_t lfs_alloc(lfs_t *lfs, bool erase);
// allocate an rbyd block
static int lfsr_rbyd_alloc(lfs_t *lfs, lfsr_rbyd_t *rbyd) {
lfs_sblock_t block = lfs_alloc(lfs, true);
if (block < 0) {
return block;
}
lfsr_rbyd_init(rbyd, block);
return 0;
}
static int lfsr_rbyd_ckecksum(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
const lfsr_ecksum_t *ecksum) {
// check that the ecksum looks right
if (lfsr_rbyd_eoff(rbyd) + ecksum->cksize >= lfs->cfg->block_size
|| lfsr_rbyd_eoff(rbyd) % lfs->cfg->prog_size != 0) {
return LFS_ERR_CORRUPT;
}
// the next valid bit must _not_ match, or a commit was attempted,
// this should hopefully stay in our cache
uint8_t e;
int err = lfsr_bd_read(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd), ecksum->cksize,
&e, 1);
if (err) {
return err;
}
if (((e >> 7)^lfsr_rbyd_isperturb(rbyd)) == lfs_parity(rbyd->cksum)) {
return LFS_ERR_CORRUPT;
}
// check that erased-state matches our checksum, if this fails
// most likely a write was interrupted
uint32_t ecksum_ = 0;
err = lfsr_bd_cksum(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd), 0,
ecksum->cksize,
&ecksum_);
if (err) {
return err;
}
// found erased-state?
return (ecksum_ == ecksum->cksum) ? 0 : LFS_ERR_CORRUPT;
}
// needed in lfsr_rbyd_fetch_ if debugging rbyd balance
static int lfsr_rbyd_lookupnext_(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_tag_t tag,
lfsr_srid_t *rid_, lfsr_tag_t *tag_, lfsr_rid_t *weight_,
lfsr_data_t *data_,
lfs_size_t *height_, lfs_size_t *bheight_);
// fetch an rbyd
static int lfsr_rbyd_fetch_(lfs_t *lfs,
lfsr_rbyd_t *rbyd, uint32_t *gcksumdelta,
lfs_block_t block, lfs_size_t trunk) {
// set up some initial state
rbyd->blocks[0] = block;
rbyd->trunk = (trunk & LFSR_RBYD_ISSHRUB) | 0;
rbyd->eoff = 0;
// ignore the shrub bit here
trunk &= ~LFSR_RBYD_ISSHRUB;
// checksum the revision count to get the cksum started
uint32_t cksum = 0;
int err = lfsr_bd_cksum(lfs, block, 0, -1, sizeof(uint32_t),
&cksum);
if (err) {
return err;
}
// temporary state until we validate a cksum
uint32_t cksum_ = cksum;
lfs_size_t off = sizeof(uint32_t);
lfs_size_t trunk_ = 0;
lfs_size_t trunk__ = 0;
lfsr_rid_t weight = 0;
lfsr_rid_t weight_ = 0;
// assume unerased until proven otherwise
lfsr_ecksum_t ecksum = {.cksize=-1};
lfsr_ecksum_t ecksum_ = {.cksize=-1};
// also find gcksumdelta, though this is only used by mdirs
uint32_t gcksumdelta_ = 0;
// scan tags, checking valid bits, cksums, etc
while (off < lfs->cfg->block_size
&& (!trunk || lfsr_rbyd_eoff(rbyd) <= trunk)) {
// read next tag
lfsr_tag_t tag;
lfsr_rid_t weight__;
lfs_size_t size;
lfs_ssize_t d = lfsr_bd_readtag(lfs, block, off, -1,
&tag, &weight__, &size,
&cksum_);
if (d < 0) {
if (d == LFS_ERR_CORRUPT) {
break;
}
return d;
}
lfs_size_t off_ = off + d;
// readtag should already check we're in-bounds
LFS_ASSERT(lfsr_tag_isalt(tag)
|| off_ + size <= lfs->cfg->block_size);
// take care of cksum
if (!lfsr_tag_isalt(tag)) {
// not an end-of-commit cksum
if (lfsr_tag_suptype(tag) != LFSR_TAG_CKSUM) {
// cksum the entry, hopefully leaving it in the cache
err = lfsr_bd_cksum(lfs, block, off_, -1, size,
&cksum_);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
// found an ecksum? save for later
if (tag == LFSR_TAG_ECKSUM) {
err = lfsr_data_readecksum(lfs,
&LFSR_DATA_DISK(block, off_,
// note this size is to make the hint do
// what we want
lfs->cfg->block_size - off_),
&ecksum_);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
// found gcksumdelta? save for later
} else if (tag == LFSR_TAG_GCKSUMDELTA) {
err = lfsr_data_readle32(lfs,
&LFSR_DATA_DISK(block, off_,
// note this size is to make the hint do
// what we want
lfs->cfg->block_size - off_),
&gcksumdelta_);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
}
// is an end-of-commit cksum
} else {
// truncated checksum?
if (size < sizeof(uint32_t)) {
break;
}
// check phase
if (lfsr_tag_phase(tag) != (block & 0x3)) {
// uh oh, phase doesn't match, mounted incorrectly?
break;
}
// check checksum
uint32_t cksum__ = 0;
err = lfsr_bd_read(lfs, block, off_, -1,
&cksum__, sizeof(uint32_t));
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
cksum__ = lfs_fromle32(&cksum__);
if (cksum_ != cksum__) {
// uh oh, checksums don't match
break;
}
// save what we've found so far
rbyd->eoff
= ((lfs_size_t)lfsr_tag_perturb(tag)
<< (8*sizeof(lfs_size_t)-1))
| (off_ + size);
rbyd->cksum = cksum;
rbyd->trunk = (LFSR_RBYD_ISSHRUB & rbyd->trunk) | trunk_;
rbyd->weight = weight;
ecksum = ecksum_;
ecksum_.cksize = -1;
if (gcksumdelta) {
*gcksumdelta = gcksumdelta_;
}
gcksumdelta_ = 0;
// revert to canonical checksum and perturb if necessary
cksum_ = cksum
^ ((lfsr_rbyd_isperturb(rbyd))
? LFS_CRC32C_ODDZERO
: 0);
}
}
// found a trunk?
if (lfsr_tag_istrunk(tag)) {
if (!(trunk && off > trunk && !trunk__)) {
// start of trunk?
if (!trunk__) {
// keep track of trunk's entry point
trunk__ = off;
// reset weight
weight_ = 0;
}
// derive weight of the tree from alt pointers
//
// NOTE we can't check for overflow/underflow here because we
// may be overeagerly parsing an invalid commit, it's ok for
// this to overflow/underflow as long as we throw it out later
// on a bad cksum
weight_ += weight__;
// end of trunk?
if (!lfsr_tag_isalt(tag)) {
// update trunk and weight, unless we are a shrub trunk
if (!lfsr_tag_isshrub(tag) || trunk__ == trunk) {
trunk_ = trunk__;
weight = weight_;
}
trunk__ = 0;
}
}
// update canonical checksum, xoring out any perturb
// state, we don't want erased-state affecting our
// canonical checksum
cksum = cksum_
^ ((lfsr_rbyd_isperturb(rbyd))
? LFS_CRC32C_ODDZERO
: 0);
}
// skip data
if (!lfsr_tag_isalt(tag)) {
off_ += size;
}
off = off_;
}
// no valid commits?
if (!lfsr_rbyd_trunk(rbyd)) {
return LFS_ERR_CORRUPT;
}
// did we end on a valid commit? we may have erased-state
bool erased = false;
if (ecksum.cksize != -1) {
// check the erased-state checksum
err = lfsr_rbyd_ckecksum(lfs, rbyd, &ecksum);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// found valid erased-state?
erased = (err != LFS_ERR_CORRUPT);
}
// used eoff=-1 to indicate when there is no erased-state
if (!erased) {
rbyd->eoff = -1;
}
#ifdef LFS_DBGRBYDFETCHES
LFS_DEBUG("Fetched rbyd 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"eoff %"PRId32", cksum %"PRIx32,
rbyd->blocks[0], lfsr_rbyd_trunk(rbyd),
rbyd->weight,
(lfsr_rbyd_eoff(rbyd) >= lfs->cfg->block_size)
? -1
: (lfs_ssize_t)lfsr_rbyd_eoff(rbyd),
rbyd->cksum);
#endif
// debugging rbyd balance? check that all branches in the rbyd have
// the same height
#ifdef LFS_DBGRBYDBALANCE
lfsr_srid_t rid = -1;
lfsr_tag_t tag = 0;
lfs_size_t min_height = 0;
lfs_size_t max_height = 0;
lfs_size_t min_bheight = 0;
lfs_size_t max_bheight = 0;
while (true) {
lfs_size_t height;
lfs_size_t bheight;
int err = lfsr_rbyd_lookupnext_(lfs, rbyd,
rid, tag+1,
&rid, &tag, NULL, NULL,
&height, &bheight);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// find the min/max height and bheight
min_height = (min_height) ? lfs_min(min_height, height) : height;
max_height = (max_height) ? lfs_max(max_height, height) : height;
min_bheight = (min_bheight) ? lfs_min(min_bheight, bheight) : bheight;
max_bheight = (max_bheight) ? lfs_max(max_bheight, bheight) : bheight;
}
LFS_DEBUG("Fetched rbyd 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"height %"PRId32"-%"PRId32", "
"bheight %"PRId32"-%"PRId32,
rbyd->blocks[0], lfsr_rbyd_trunk(rbyd),
rbyd->weight,
min_height, max_height,
min_bheight, max_bheight);
// all branches in the rbyd should have the same bheight
LFS_ASSERT(max_bheight == min_bheight);
// this limits alt height to no worse than 2*bheight+2 (2*bheight+1
// for normal appends, 2*bheight+2 with range removals)
LFS_ASSERT(max_height <= 2*min_height+2);
#endif
return 0;
}
static int lfsr_rbyd_fetch(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfs_block_t block, lfs_size_t trunk) {
return lfsr_rbyd_fetch_(lfs, rbyd, NULL, block, trunk);
}
// a more aggressive fetch when checksum is known
static int lfsr_rbyd_fetchck(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfs_block_t block, lfs_size_t trunk,
uint32_t cksum) {
int err = lfsr_rbyd_fetch(lfs, rbyd, block, trunk);
if (err) {
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Found corrupted rbyd 0x%"PRIx32".%"PRIx32", "
"cksum %08"PRIx32,
block, trunk, cksum);
}
return err;
}
// test that our cksum matches what's expected
//
// it should be noted that this is very unlikely to happen without the
// above fetch failing, since that would require the rbyd to have the
// same trunk and pass its internal cksum
if (rbyd->cksum != cksum) {
LFS_ERROR("Found rbyd cksum mismatch 0x%"PRIx32".%"PRIx32", "
"cksum %08"PRIx32" (!= %08"PRIx32")",
rbyd->blocks[0], lfsr_rbyd_trunk(rbyd),
rbyd->cksum, cksum);
return LFS_ERR_CORRUPT;
}
// if trunk/weight mismatch _after_ cksums match, that's not a storage
// error, that's a programming error
LFS_ASSERT(lfsr_rbyd_trunk(rbyd) == trunk);
return 0;
}
// our core rbyd lookup algorithm
//
// finds the next rid+tag such that rid_+tag_ >= rid+tag
static int lfsr_rbyd_lookupnext_(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_tag_t tag,
lfsr_srid_t *rid_, lfsr_tag_t *tag_, lfsr_rid_t *weight_,
lfsr_data_t *data_,
lfs_size_t *height_, lfs_size_t *bheight_) {
// these bits should be clear at this point
LFS_ASSERT(lfsr_tag_mode(tag) == 0);
// make sure we never look up zero tags, the way we create
// unreachable tags has a hole here
tag = lfs_max(tag, 0x1);
// out of bounds? no trunk yet?
if (rid >= (lfsr_srid_t)rbyd->weight || !lfsr_rbyd_trunk(rbyd)) {
return LFS_ERR_NOENT;
}
// optionally find height/bheight for debugging rbyd balance
if (height_) {
*height_ = 0;
}
if (bheight_) {
*bheight_ = 0;
}
// keep track of bounds as we descend down the tree
lfs_size_t branch = lfsr_rbyd_trunk(rbyd);
lfsr_srid_t lower_rid = 0;
lfsr_srid_t upper_rid = rbyd->weight;
// descend down tree
while (true) {
lfsr_tag_t alt;
lfsr_rid_t weight;
lfs_size_t jump;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
rbyd->blocks[0], branch, 0,
&alt, &weight, &jump,
NULL);
if (d < 0) {
return d;
}
// found an alt?
if (lfsr_tag_isalt(alt)) {
lfs_size_t branch_ = branch + d;
// keep track of height for debugging
if (height_) {
*height_ += 1;
}
if (bheight_
// only count black+followed alts towards bheight
&& (lfsr_tag_isblack(alt)
|| lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
rid, tag))) {
*bheight_ += 1;
}
// take alt?
if (lfsr_tag_follow(
alt, weight,
lower_rid, upper_rid,
rid, tag)) {
lfsr_tag_flip(
&alt, &weight,
lower_rid, upper_rid);
branch_ = branch - jump;
}
lfsr_tag_trim(
alt, weight,
&lower_rid, &upper_rid,
NULL, NULL);
LFS_ASSERT(branch_ != branch);
branch = branch_;
// found end of tree?
} else {
// update the tag rid
lfsr_srid_t rid__ = upper_rid-1;
lfsr_tag_t tag__ = lfsr_tag_key(alt);
// not what we're looking for?
if (!tag__
|| rid__ < rid
|| (rid__ == rid && tag__ < tag)) {
return LFS_ERR_NOENT;
}
// save what we found
// TODO how many of these need to be conditional?
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = upper_rid - lower_rid;
}
if (data_) {
*data_ = LFSR_DATA_DISK(rbyd->blocks[0], branch + d, jump);
}
return 0;
}
}
}
// finds the next rid_+tag_ such that rid_+tag_ >= rid+tag
static int lfsr_rbyd_lookupnext(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_tag_t tag,
lfsr_srid_t *rid_, lfsr_tag_t *tag_, lfsr_rid_t *weight_,
lfsr_data_t *data_) {
return lfsr_rbyd_lookupnext_(lfs, rbyd, rid, tag,
rid_, tag_, weight_, data_,
NULL, NULL);
}
// lookup assumes a known rid
static int lfsr_rbyd_lookup(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
lfsr_srid_t rid__;
lfsr_tag_t tag__;
int err = lfsr_rbyd_lookupnext(lfs, rbyd, rid, lfsr_tag_key(tag),
&rid__, &tag__, NULL, data_);
if (err) {
return err;
}
// lookup finds the next-smallest tag, all we need to do is fail if it
// picks up the wrong tag
if (rid__ != rid
|| (tag__ & lfsr_tag_mask(tag)) != (tag & lfsr_tag_mask(tag))) {
return LFS_ERR_NOENT;
}
if (tag_) {
*tag_ = tag__;
}
return 0;
}
// rbyd append operations
// append a revision count
//
// this is optional, if not called revision count defaults to 0 (for btrees)
static int lfsr_rbyd_appendrev(lfs_t *lfs, lfsr_rbyd_t *rbyd, uint32_t rev) {
// should only be called before any tags are written
LFS_ASSERT(rbyd->eoff == 0);
LFS_ASSERT(rbyd->cksum == 0);
// revision count stored as le32, we don't use a leb128 encoding as we
// intentionally allow the revision count to overflow
uint8_t rev_buf[sizeof(uint32_t)];
lfs_tole32(rev, &rev_buf);
int err = lfsr_bd_prog(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd),
&rev_buf, sizeof(uint32_t),
&rbyd->cksum, false);
if (err) {
return err;
}
rbyd->eoff += sizeof(uint32_t);
return 0;
}
// other low-level appends
static int lfsr_rbyd_appendtag(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_tag_t tag, lfsr_rid_t weight, lfs_size_t size) {
// tag must not be internal at this point
LFS_ASSERT(!lfsr_tag_isinternal(tag));
// bit 7 is reserved for future subtype extensions
LFS_ASSERT(!(tag & 0x80));
// do we fit?
if (lfsr_rbyd_eoff(rbyd) + LFSR_TAG_DSIZE
> lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
lfs_ssize_t d = lfsr_bd_progtag(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd), lfsr_rbyd_isperturb(rbyd),
tag, weight, size,
&rbyd->cksum, false);
if (d < 0) {
return d;
}
rbyd->eoff += d;
#ifdef LFS_CKMETAPARITY
// keep track of most recent parity
lfs->ptail.block = rbyd->blocks[0];
lfs->ptail.off
= ((lfs_size_t)(
lfs_parity(rbyd->cksum) ^ lfsr_rbyd_isperturb(rbyd)
) << (8*sizeof(lfs_size_t)-1))
| lfsr_rbyd_eoff(rbyd);
#endif
return 0;
}
// needed in lfsr_rbyd_appendrattr_
typedef struct lfsr_geometry lfsr_geometry_t;
static lfsr_data_t lfsr_data_fromgeometry(const lfsr_geometry_t *geometry,
uint8_t buffer[static LFSR_GEOMETRY_DSIZE]);
static lfsr_data_t lfsr_data_frombptr(const lfsr_bptr_t *bptr,
uint8_t buffer[static LFSR_BPTR_DSIZE]);
static lfsr_data_t lfsr_data_fromshrub(const lfsr_shrub_t *shrub,
uint8_t buffer[static LFSR_SHRUB_DSIZE]);
static lfsr_data_t lfsr_data_frombtree(const lfsr_btree_t *btree,
uint8_t buffer[static LFSR_BTREE_DSIZE]);
static lfsr_data_t lfsr_data_frommptr(const lfs_block_t mptr[static 2],
uint8_t buffer[static LFSR_MPTR_DSIZE]);
// encode rattrs
static int lfsr_rbyd_appendrattr_(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_rattr_t rattr) {
// tag must not be internal at this point
LFS_ASSERT(!lfsr_tag_isinternal(rattr.tag));
// bit 7 is reserved for future subtype extensions
LFS_ASSERT(!(rattr.tag & 0x80));
// encode lazy tags?
//
// we encode most tags lazily as this heavily reduces stack usage,
// though this does make us less gc-able at compile time
//
// note we only encode lazily if the rattr uses a direct buffer,
// explicit data bypasses the lazy encoding, which is necessary to
// allow copies during compaction, relocation, etc
//
lfs_size_t size;
const void *data;
int16_t count;
struct {
// uh, there's probably a better way to do this, but I'm not
// sure what it is
union {
uint8_t buf[LFS_MAX(
LFSR_LE32_DSIZE,
LFS_MAX(
LFSR_LEB128_DSIZE,
LFS_MAX(
LFSR_GEOMETRY_DSIZE,
LFS_MAX(
LFSR_BPTR_DSIZE,
LFS_MAX(
LFSR_SHRUB_DSIZE,
LFS_MAX(
LFSR_BTREE_DSIZE,
LFS_MAX(
LFSR_MPTR_DSIZE,
LFSR_ECKSUM_DSIZE)))))))];
struct {
lfsr_data_t datas[2];
uint8_t buf[LFSR_LEB128_DSIZE];
} name;
} u;
} ctx;
// le32?
if (rattr.count >= 0
&& (rattr.tag == LFSR_TAG_RCOMPAT
|| rattr.tag == LFSR_TAG_WCOMPAT
|| rattr.tag == LFSR_TAG_OCOMPAT
|| rattr.tag == LFSR_TAG_GCKSUMDELTA)) {
lfsr_data_t data_ = lfsr_data_fromle32(rattr.u.le32, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// leb128?
} else if (rattr.count >= 0
&& (rattr.tag == LFSR_TAG_NAMELIMIT
|| rattr.tag == LFSR_TAG_FILELIMIT
|| rattr.tag == LFSR_TAG_DID)) {
// leb128s should not exceed 31-bits
LFS_ASSERT(rattr.u.leb128 <= 0x7fffffff);
// little-leb128s should not exceed 28-bits
LFS_ASSERT(rattr.tag != LFSR_TAG_NAMELIMIT
|| rattr.u.leb128 <= 0x0fffffff);
lfsr_data_t data_ = lfsr_data_fromleb128(rattr.u.leb128, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// geometry?
} else if (rattr.count >= 0
&& rattr.tag == LFSR_TAG_GEOMETRY) {
lfsr_data_t data_ = lfsr_data_fromgeometry(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// name?
} else if (rattr.count >= 0
&& lfsr_tag_suptype(rattr.tag) == LFSR_TAG_NAME) {
const lfsr_name_t *name = rattr.u.etc;
ctx.u.name.datas[0] = lfsr_data_fromleb128(name->did, ctx.u.name.buf);
ctx.u.name.datas[1] = LFSR_DATA_BUF(name->name, name->name_len);
size = lfsr_data_size(ctx.u.name.datas[0]) + name->name_len;
data = &ctx.u.name.datas;
count = -2;
// bptr?
} else if (rattr.count >= 0
&& (rattr.tag == LFSR_TAG_BLOCK
|| rattr.tag == (LFSR_TAG_SHRUB | LFSR_TAG_BLOCK))) {
lfsr_data_t data_ = lfsr_data_frombptr(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// shrub trunk?
} else if (rattr.count >= 0
&& rattr.tag == LFSR_TAG_BSHRUB) {
// note unlike the other lazy tags, we _need_ to lazily encode
// shrub trunks, since they change underneath us during mdir
// compactions, relocations, etc
lfsr_data_t data_ = lfsr_data_fromshrub(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// btree?
} else if (rattr.count >= 0
&& (rattr.tag == LFSR_TAG_BTREE
|| rattr.tag == LFSR_TAG_MTREE)) {
lfsr_data_t data_ = lfsr_data_frombtree(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// mptr?
} else if (rattr.count >= 0
&& (rattr.tag == LFSR_TAG_MROOT
|| rattr.tag == LFSR_TAG_MDIR)) {
lfsr_data_t data_ = lfsr_data_frommptr(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// ecksum?
} else if (rattr.count >= 0
&& rattr.tag == LFSR_TAG_ECKSUM) {
lfsr_data_t data_ = lfsr_data_fromecksum(rattr.u.etc, ctx.u.buf);
size = lfsr_data_size(data_);
data = ctx.u.buf;
count = size;
// default to raw data
} else {
size = lfsr_rattr_dsize(rattr);
data = rattr.u.datas;
count = rattr.count;
}
// now everything should be raw data, either in-ram or on-disk
// do we fit?
if (lfsr_rbyd_eoff(rbyd) + LFSR_TAG_DSIZE + size
> lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
// append tag
int err = lfsr_rbyd_appendtag(lfs, rbyd,
rattr.tag, rattr.weight, size);
if (err) {
return err;
}
// direct buffer?
if (count >= 0) {
err = lfsr_bd_prog(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd), data, count,
&rbyd->cksum, false);
if (err) {
return err;
}
rbyd->eoff += count;
// indirect concatenated data?
} else {
const lfsr_data_t *datas = data;
lfs_size_t data_count = -count;
for (lfs_size_t i = 0; i < data_count; i++) {
err = lfsr_bd_progdata(lfs,
rbyd->blocks[0], lfsr_rbyd_eoff(rbyd), datas[i],
&rbyd->cksum, false);
if (err) {
return err;
}
rbyd->eoff += lfsr_data_size(datas[i]);
}
}
#ifdef LFS_CKMETAPARITY
// keep track of most recent parity
lfs->ptail.block = rbyd->blocks[0];
lfs->ptail.off
= ((lfs_size_t)(
lfs_parity(rbyd->cksum) ^ lfsr_rbyd_isperturb(rbyd)
) << (8*sizeof(lfs_size_t)-1))
| lfsr_rbyd_eoff(rbyd);
#endif
return 0;
}
// checks before we append
static int lfsr_rbyd_appendinit(lfs_t *lfs, lfsr_rbyd_t *rbyd) {
// must fetch before mutating!
LFS_ASSERT(lfsr_rbyd_isfetched(rbyd));
// we can't do anything if we're not erased
if (lfsr_rbyd_eoff(rbyd) >= lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
// make sure every rbyd starts with a revision count
if (rbyd->eoff == 0) {
int err = lfsr_rbyd_appendrev(lfs, rbyd, 0);
if (err) {
return err;
}
}
return 0;
}
// helper functions for managing the 3-element fifo used in
// lfsr_rbyd_appendrattr
typedef struct lfsr_alt {
lfsr_tag_t alt;
lfsr_rid_t weight;
lfs_size_t jump;
} lfsr_alt_t;
static int lfsr_rbyd_p_flush(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_alt_t p[static 3],
int count) {
// write out some number of alt pointers in our queue
for (int i = 0; i < count; i++) {
if (p[3-1-i].alt) {
// jump=0 represents an unreachable alt, we do write out
// unreachable alts sometimes in order to maintain the
// balance of the tree
LFS_ASSERT(p[3-1-i].jump || lfsr_tag_isblack(p[3-1-i].alt));
lfsr_tag_t alt = p[3-1-i].alt;
lfsr_rid_t weight = p[3-1-i].weight;
// change to a relative jump at the last minute
lfs_size_t jump = (p[3-1-i].jump)
? lfsr_rbyd_eoff(rbyd) - p[3-1-i].jump
: 0;
int err = lfsr_rbyd_appendtag(lfs, rbyd, alt, weight, jump);
if (err) {
return err;
}
}
}
return 0;
}
static inline int lfsr_rbyd_p_push(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_alt_t p[static 3],
lfsr_tag_t alt, lfsr_rid_t weight, lfs_size_t jump) {
// jump should actually be in the rbyd
LFS_ASSERT(jump < lfsr_rbyd_eoff(rbyd));
int err = lfsr_rbyd_p_flush(lfs, rbyd, p, 1);
if (err) {
return err;
}
lfs_memmove(p+1, p, 2*sizeof(lfsr_alt_t));
p[0].alt = alt;
p[0].weight = weight;
p[0].jump = jump;
return 0;
}
static inline void lfsr_rbyd_p_pop(
lfsr_alt_t p[static 3]) {
lfs_memmove(p, p+1, 2*sizeof(lfsr_alt_t));
p[2].alt = 0;
}
static void lfsr_rbyd_p_recolor(
lfsr_alt_t p[static 3]) {
// propagate a red edge upwards
p[0].alt &= ~LFSR_TAG_R;
if (p[1].alt) {
p[1].alt |= LFSR_TAG_R;
// unreachable alt? we can prune this now
if (!p[1].jump) {
p[1] = p[2];
p[2].alt = 0;
// reorder so that top two edges always go in the same direction
} else if (lfsr_tag_isred(p[2].alt)) {
if (lfsr_tag_isparallel(p[1].alt, p[2].alt)) {
// no reorder needed
} else if (lfsr_tag_isparallel(p[0].alt, p[2].alt)) {
lfsr_tag_t alt_ = p[1].alt;
lfsr_rid_t weight_ = p[1].weight;
lfs_size_t jump_ = p[1].jump;
p[1].alt = p[0].alt | LFSR_TAG_R;
p[1].weight = p[0].weight;
p[1].jump = p[0].jump;
p[0].alt = alt_ & ~LFSR_TAG_R;
p[0].weight = weight_;
p[0].jump = jump_;
} else if (lfsr_tag_isparallel(p[0].alt, p[1].alt)) {
lfsr_tag_t alt_ = p[2].alt;
lfsr_rid_t weight_ = p[2].weight;
lfs_size_t jump_ = p[2].jump;
p[2].alt = p[1].alt | LFSR_TAG_R;
p[2].weight = p[1].weight;
p[2].jump = p[1].jump;
p[1].alt = p[0].alt | LFSR_TAG_R;
p[1].weight = p[0].weight;
p[1].jump = p[0].jump;
p[0].alt = alt_ & ~LFSR_TAG_R;
p[0].weight = weight_;
p[0].jump = jump_;
} else {
LFS_UNREACHABLE();
}
}
}
}
// our core rbyd append algorithm
static int lfsr_rbyd_appendrattr(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_rattr_t rattr) {
// must fetch before mutating!
LFS_ASSERT(lfsr_rbyd_isfetched(rbyd));
// tag must not be internal at this point
LFS_ASSERT(!lfsr_tag_isinternal(rattr.tag));
// bit 7 is reserved for future subtype extensions
LFS_ASSERT(!(rattr.tag & 0x80));
// you can't delete more than what's in the rbyd
LFS_ASSERT(rattr.weight >= -(lfsr_srid_t)rbyd->weight);
// ignore noops
if (lfsr_rattr_isnoop(rattr)) {
return 0;
}
// begin appending
int err = lfsr_rbyd_appendinit(lfs, rbyd);
if (err) {
return err;
}
// figure out what range of tags we're operating on
lfsr_srid_t a_rid;
lfsr_srid_t b_rid;
lfsr_tag_t a_tag;
lfsr_tag_t b_tag;
if (!lfsr_tag_isgrow(rattr.tag) && rattr.weight != 0) {
if (rattr.weight > 0) {
LFS_ASSERT(rid <= (lfsr_srid_t)rbyd->weight);
// it's a bit ugly, but adjusting the rid here makes the following
// logic work out more consistently
rid -= 1;
a_rid = rid + 1;
b_rid = rid + 1;
} else {
LFS_ASSERT(rid < (lfsr_srid_t)rbyd->weight);
// it's a bit ugly, but adjusting the rid here makes the following
// logic work out more consistently
rid += 1;
a_rid = rid - lfs_smax(-rattr.weight, 0);
b_rid = rid;
}
a_tag = 0;
b_tag = 0;
} else {
LFS_ASSERT(rid < (lfsr_srid_t)rbyd->weight);
a_rid = rid - lfs_smax(-rattr.weight, 0);
b_rid = rid;
// note both normal and rm wide-tags have the same bounds, really it's
// the normal non-wide-tags that are an outlier here
if (lfsr_tag_ismask12(rattr.tag)) {
a_tag = 0x000;
b_tag = 0xfff;
} else if (lfsr_tag_ismask8(rattr.tag)) {
a_tag = (rattr.tag & 0xf00);
b_tag = (rattr.tag & 0xf00) + 0x100;
} else if (lfsr_tag_ismask2(rattr.tag)) {
a_tag = (rattr.tag & 0xffc);
b_tag = (rattr.tag & 0xffc) + 0x004;
} else if (lfsr_tag_isrm(rattr.tag)) {
a_tag = lfsr_tag_key(rattr.tag);
b_tag = lfsr_tag_key(rattr.tag) + 1;
} else {
a_tag = lfsr_tag_key(rattr.tag);
b_tag = lfsr_tag_key(rattr.tag);
}
}
a_tag = lfs_max(a_tag, 0x1);
b_tag = lfs_max(b_tag, 0x1);
// keep track of diverged state
//
// this is only used if we operate on a range of tags, in which case
// we may need to write two trunks
//
// to pull this off, we make two passes:
// 1. to write the common trunk + diverged-lower trunk
// 2. to write the common trunk + diverged-upper trunk, stitching the
// two diverged trunks together where they diverged
//
bool diverged = false;
lfsr_tag_t d_tag = 0;
lfsr_srid_t d_weight = 0;
// follow the current trunk
lfs_size_t branch = lfsr_rbyd_trunk(rbyd);
trunk:;
// the new trunk starts here
lfs_size_t trunk_ = lfsr_rbyd_eoff(rbyd);
// keep track of bounds as we descend down the tree
//
// this gets a bit confusing as we also may need to keep
// track of both the lower and upper bounds of diverging paths
// in the case of range deletions
lfsr_srid_t lower_rid = 0;
lfsr_srid_t upper_rid = rbyd->weight;
lfsr_tag_t lower_tag = 0x000;
lfsr_tag_t upper_tag = 0xfff;
// no trunk yet?
if (!branch) {
goto leaf;
}
// queue of pending alts we can emulate rotations with
lfsr_alt_t p[3] = {{0}, {0}, {0}};
// keep track of the last incoming branch for yellow splits
lfs_size_t y_branch = 0;
// keep track of the tag we find at the end of the trunk
lfsr_tag_t tag_ = 0;
// descend down tree, building alt pointers
while (true) {
// keep track of incoming branch
if (lfsr_tag_isblack(p[0].alt)) {
y_branch = branch;
}
// read the alt pointer
lfsr_tag_t alt;
lfsr_rid_t weight;
lfs_size_t jump;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
rbyd->blocks[0], branch, 0,
&alt, &weight, &jump,
NULL);
if (d < 0) {
return d;
}
// found an alt?
if (lfsr_tag_isalt(alt)) {
// make jump absolute
jump = branch - jump;
lfs_size_t branch_ = branch + d;
// yellow alts should be parallel
LFS_ASSERT(!(lfsr_tag_isred(alt) && lfsr_tag_isred(p[0].alt))
|| lfsr_tag_isparallel(alt, p[0].alt));
// take black alt? needs a flip
// <b >b
// .-'| => .-'|
// 1 2 1 2 1
if (lfsr_tag_follow2(
alt, weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid,
a_rid, a_tag)) {
lfsr_tag_flip2(
&alt, &weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid);
LFS_SWAP(lfs_size_t, &jump, &branch_);
}
// should've taken red alt? needs a flip
// <r >r
// .----'| .-'|
// | <b => | >b
// | .-'| .--|-'|
// 1 2 3 1 2 3 1
if (lfsr_tag_isred(p[0].alt)
&& lfsr_tag_follow(
p[0].alt, p[0].weight,
lower_rid, upper_rid,
a_rid, a_tag)) {
LFS_SWAP(lfsr_tag_t, &p[0].alt, &alt);
LFS_SWAP(lfsr_rid_t, &p[0].weight, &weight);
LFS_SWAP(lfs_size_t, &p[0].jump, &jump);
alt = (alt & ~LFSR_TAG_R) | (p[0].alt & LFSR_TAG_R);
p[0].alt |= LFSR_TAG_R;
lfsr_tag_flip2(
&alt, &weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid);
LFS_SWAP(lfs_size_t, &jump, &branch_);
}
// do bounds want to take different paths? begin diverging
// >b <b
// .-'| .-'|
// <b => | nb => nb |
// .----'| .--------|--' .-----------' |
// <b <b | <b | nb
// .-'| .-'| | .-'| | .-----'
// 1 2 3 4 1 2 3 4 x 1 2 3 4 x x
bool diverging_b = lfsr_tag_diverging2(
alt, weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid,
a_rid, a_tag,
b_rid, b_tag);
bool diverging_r = lfsr_tag_isred(p[0].alt)
&& lfsr_tag_diverging(
p[0].alt, p[0].weight,
lower_rid, upper_rid,
a_rid, a_tag,
b_rid, b_tag);
if (!diverged) {
// both diverging? collapse
// <r >b
// .----'| .-'|
// | <b => | |
// | .-'| .-----|--'
// 1 2 3 1 2 3 x
if (diverging_b && diverging_r) {
LFS_ASSERT(a_rid < b_rid || a_tag < b_tag);
LFS_ASSERT(lfsr_tag_isparallel(alt, p[0].alt));
weight += p[0].weight;
jump = p[0].jump;
lfsr_rbyd_p_pop(p);
diverging_r = false;
}
// diverging? start trimming inner alts
// >b
// .-'|
// <b => | nb
// .----'| .--------|--'
// <b <b | <b
// .-'| .-'| | .-'|
// 1 2 3 4 1 2 3 4 x
if ((diverging_b || diverging_r)
// diverging black?
&& (lfsr_tag_isblack(alt)
// give up if we find a yellow alt
|| (lfsr_tag_isred(p[0].alt)))) {
diverged = true;
// diverging upper? stitch together both trunks
// >b <b
// .-'| .-'|
// | nb => nb |
// .--------|--' .-----------' |
// | <b | nb
// | .-'| | .-----'
// 1 2 3 4 x 1 2 3 4 x x
if (a_rid > b_rid || a_tag > b_tag) {
LFS_ASSERT(!diverging_r);
alt = LFSR_TAG_ALT(
alt & LFSR_TAG_R,
LFSR_TAG_LE,
d_tag);
weight -= d_weight;
lower_rid += d_weight;
}
}
} else {
// diverged? trim so alt will be pruned
// <b => nb
// .-'| .--'
// 3 4 3 4 x
if (diverging_b) {
lfsr_tag_trim(
alt, weight,
&lower_rid, &upper_rid,
&lower_tag, &upper_tag);
weight = 0;
}
}
// note we need to prioritize yellow-split pruning here,
// which unfortunately makes this logic a bit of a mess
// prune unreachable yellow-split yellow alts
// <b >b
// .-'| .-'|
// <y | | |
// .-------'| | | |
// | <r | => | >b
// | .----' | .--------|-'|
// | | <b | <b |
// | | .----'| | .----'| |
// 1 2 3 4 4 1 2 3 4 4 1
if (lfsr_tag_isred(p[0].alt)
&& lfsr_tag_unreachable(
p[0].alt, p[0].weight,
lower_rid, upper_rid,
lower_tag, upper_tag)
&& p[0].jump > branch) {
alt &= ~LFSR_TAG_R;
lfsr_rbyd_p_pop(p);
// prune unreachable yellow-split red alts
// <b >b
// .-'| .-'|
// <y | | <b
// .-------'| | .-----------|-'|
// | <r | => | | |
// | .----' | | | |
// | | <b | <b |
// | | .----'| | .----'| |
// 1 2 3 4 4 1 2 3 4 4 2
} else if (lfsr_tag_isred(p[0].alt)
&& lfsr_tag_unreachable2(
alt, weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid,
lower_tag, upper_tag)
&& jump > branch) {
alt = p[0].alt & ~LFSR_TAG_R;
weight = p[0].weight;
jump = p[0].jump;
lfsr_rbyd_p_pop(p);
}
// prune red alts
if (lfsr_tag_isred(p[0].alt)
&& lfsr_tag_unreachable(
p[0].alt, p[0].weight,
lower_rid, upper_rid,
lower_tag, upper_tag)) {
// prune unreachable recolorable alts
// <r => <b
// .----'| .----'|
// | <b | |
// | .-'| | .--'
// 1 2 3 1 2 3 x
LFS_ASSERT(p[0].jump < branch);
lfsr_rbyd_p_pop(p);
}
// prune black alts
if (lfsr_tag_unreachable2(
alt, weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid,
lower_tag, upper_tag)) {
// root alts are a special case that we can prune
// immediately
// <b => <b
// .----'| .----'|
// <b <b | |
// .-'| .-'| | .--'
// 1 3 4 5 1 3 4 5 x
if (!p[0].alt) {
branch = branch_;
continue;
// prune unreachable recolorable alts
// <r => <b
// .----'| .-------'|
// | <b | |
// | .-'| | .-----'
// 1 2 3 1 2 3 x
} else if (lfsr_tag_isred(p[0].alt)) {
LFS_ASSERT(jump < branch);
alt = (p[0].alt & ~LFSR_TAG_R) | (alt & LFSR_TAG_R);
weight = p[0].weight;
jump = p[0].jump;
lfsr_rbyd_p_pop(p);
// we can't prune non-root black alts or we risk
// breaking the color balance of our tree, so instead
// we just mark these alts as unreachable (jump=0), and
// collapse them if we propagate a red edge later
// <b => nb
// .-'| .--'
// 3 4 3 4 x
} else if (lfsr_tag_isblack(alt)) {
alt = LFSR_TAG_ALT(
LFSR_TAG_B,
LFSR_TAG_LE,
(diverged && (a_rid > b_rid || a_tag > b_tag))
? d_tag
: lower_tag);
LFS_ASSERT(weight == 0);
// jump=0 also asserts the alt is unreachable (or
// else we loop indefinitely), and uses the minimum
// alt encoding
jump = 0;
}
}
// two reds makes a yellow, split?
//
// note we've lost the original yellow edge because of flips, but
// we know the red edge is the only branch_ > branch
if (lfsr_tag_isred(alt) && lfsr_tag_isred(p[0].alt)) {
// if we take the red or yellow alt we can just point
// to the black alt
// <y >b
// .-------'| .-'|
// | <r | >b
// | .----'| => .-----|-'|
// | | <b | <b |
// | | .-'| | .-'| |
// 1 2 3 4 1 2 3 4 1
if (branch_ < branch) {
if (jump > branch) {
LFS_SWAP(lfsr_tag_t, &p[0].alt, &alt);
LFS_SWAP(lfsr_rid_t, &p[0].weight, &weight);
LFS_SWAP(lfs_size_t, &p[0].jump, &jump);
}
alt &= ~LFSR_TAG_R;
lfsr_tag_trim(
p[0].alt, p[0].weight,
&lower_rid, &upper_rid,
&lower_tag, &upper_tag);
lfsr_rbyd_p_recolor(p);
// otherwise we need to point to the yellow alt and
// prune later
// <b
// .-'|
// <y <y |
// .-------'| .-------'| |
// | <r => | <r |
// | .----'| | .----' |
// | | <b | | <b
// | | .-'| | | .----'|
// 1 2 3 4 1 2 3 4 4
} else {
LFS_ASSERT(y_branch != 0);
p[0].alt = alt;
p[0].weight += weight;
p[0].jump = y_branch;
lfsr_tag_trim(
p[0].alt, p[0].weight,
&lower_rid, &upper_rid,
&lower_tag, &upper_tag);
lfsr_rbyd_p_recolor(p);
branch = branch_;
continue;
}
}
// red alt? we need to read the rest of the 2-3-4 node
if (lfsr_tag_isred(alt)) {
// undo flip temporarily
if (branch_ < branch) {
lfsr_tag_flip2(
&alt, &weight,
p[0].alt, p[0].weight,
lower_rid, upper_rid);
LFS_SWAP(lfs_size_t, &jump, &branch_);
}
// black alt? terminate 2-3-4 nodes
} else {
// trim alts from our current bounds
lfsr_tag_trim2(
alt, weight,
p[0].alt, p[0].weight,
&lower_rid, &upper_rid,
&lower_tag, &upper_tag);
}
// push alt onto our queue
err = lfsr_rbyd_p_push(lfs, rbyd, p,
alt, weight, jump);
if (err) {
return err;
}
// continue to next alt
LFS_ASSERT(branch_ != branch);
branch = branch_;
continue;
// found end of tree?
} else {
// update the found tag
tag_ = lfsr_tag_key(alt);
// the last alt should always end up black
LFS_ASSERT(lfsr_tag_isblack(p[0].alt));
if (diverged) {
// diverged lower trunk? move on to upper trunk
if (a_rid < b_rid || a_tag < b_tag) {
// keep track of the lower diverged bound
d_tag = lower_tag;
d_weight = upper_rid - lower_rid;
// flush any pending alts
err = lfsr_rbyd_p_flush(lfs, rbyd, p, 3);
if (err) {
return err;
}
// terminate diverged trunk with an unreachable tag
err = lfsr_rbyd_appendrattr_(lfs, rbyd, LFSR_RATTR(
(lfsr_rbyd_isshrub(rbyd) ? LFSR_TAG_SHRUB : 0)
| LFSR_TAG_NULL,
0));
if (err) {
return err;
}
// swap tag/rid and move on to upper trunk
diverged = false;
branch = trunk_;
LFS_SWAP(lfsr_tag_t, &a_tag, &b_tag);
LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
goto trunk;
} else {
// use the lower diverged bound for leaf weight
// calculation
lower_rid -= d_weight;
lower_tag = d_tag;
}
}
goto stem;
}
}
stem:;
// split leaf nodes?
//
// note we bias the weights here so that lfsr_rbyd_lookupnext
// always finds the next biggest tag
//
// note also if tag_ is null, we found a removed tag that we should just
// prune
//
// this gets real messy because we have a lot of special behavior built in:
// - default => split if tags mismatch
// - weight>0, !grow => split if tags mismatch or we're inserting a new tag
// - rm-bit set => never split, but emit alt-always tags, making our
// tag effectively unreachable
//
lfsr_tag_t alt = 0;
lfsr_rid_t weight = 0;
if (tag_
&& (upper_rid-1 < rid-lfs_smax(-rattr.weight, 0)
|| (upper_rid-1 == rid-lfs_smax(-rattr.weight, 0)
&& ((!lfsr_tag_isgrow(rattr.tag) && rattr.weight > 0)
|| ((tag_ & lfsr_tag_mask(rattr.tag))
< (rattr.tag & lfsr_tag_mask(rattr.tag))))))) {
if (lfsr_tag_isrm(rattr.tag) || !lfsr_tag_key(rattr.tag)) {
// if removed, make our tag unreachable
alt = LFSR_TAG_ALT(LFSR_TAG_B, LFSR_TAG_GT, lower_tag);
weight = upper_rid - lower_rid + rattr.weight;
upper_rid -= weight;
} else {
// split less than
alt = LFSR_TAG_ALT(LFSR_TAG_B, LFSR_TAG_LE, tag_);
weight = upper_rid - lower_rid;
lower_rid += weight;
}
} else if (tag_
&& (upper_rid-1 > rid
|| (upper_rid-1 == rid
&& ((!lfsr_tag_isgrow(rattr.tag) && rattr.weight > 0)
|| ((tag_ & lfsr_tag_mask(rattr.tag))
> (rattr.tag & lfsr_tag_mask(rattr.tag))))))) {
if (lfsr_tag_isrm(rattr.tag) || !lfsr_tag_key(rattr.tag)) {
// if removed, make our tag unreachable
alt = LFSR_TAG_ALT(LFSR_TAG_B, LFSR_TAG_GT, lower_tag);
weight = upper_rid - lower_rid + rattr.weight;
upper_rid -= weight;
} else {
// split greater than
alt = LFSR_TAG_ALT(LFSR_TAG_B, LFSR_TAG_GT, rattr.tag);
weight = upper_rid - (rid+1);
upper_rid -= weight;
}
}
if (alt) {
err = lfsr_rbyd_p_push(lfs, rbyd, p,
alt, weight, branch);
if (err) {
return err;
}
// introduce a red edge
lfsr_rbyd_p_recolor(p);
}
// flush any pending alts
err = lfsr_rbyd_p_flush(lfs, rbyd, p, 3);
if (err) {
return err;
}
leaf:;
// write the actual tag
//
// note we always need a non-alt to terminate the trunk, otherwise we
// can't find trunks during fetch
err = lfsr_rbyd_appendrattr_(lfs, rbyd, LFSR_RATTR_(
// mark as shrub if we are a shrub
(lfsr_rbyd_isshrub(rbyd) ? LFSR_TAG_SHRUB : 0)
// rm => null, otherwise strip off control bits
| ((lfsr_tag_isrm(rattr.tag))
? LFSR_TAG_NULL
: lfsr_tag_key(rattr.tag)),
upper_rid - lower_rid + rattr.weight,
rattr.u, rattr.count));
if (err) {
return err;
}
// update the trunk and weight
rbyd->trunk = (rbyd->trunk & LFSR_RBYD_ISSHRUB) | trunk_;
rbyd->weight += rattr.weight;
return 0;
}
static int lfsr_rbyd_appendcksum_(lfs_t *lfs, lfsr_rbyd_t *rbyd,
uint32_t cksum) {
// align to the next prog unit
//
// this gets a bit complicated as we have two types of cksums:
//
// - 9-word cksum with ecksum to check following prog (middle of block):
// .---+---+---+---. ecksum tag: 1 be16 2 bytes
// | tag | 0 |siz| ecksum weight (0): 1 leb128 1 byte
// +---+---+---+---+ ecksum size: 1 leb128 1 byte
// | ecksize | ecksum cksize: 1 leb128 <=4 bytes
// +---+- -+- -+- -+ ecksum cksum: 1 le32 4 bytes
// | ecksum |
// +---+---+---+---+- -+- -+- -. cksum tag: 1 be16 2 bytes
// | tag | 0 | size | cksum weight (0): 1 leb128 1 byte
// +---+---+---+---+- -+- -+- -' cksum size: 1 leb128 <=4 bytes
// | cksum | cksum cksum: 1 le32 4 bytes
// '---+---+---+---' total: <=23 bytes
//
// - 4-word cksum with no following prog (end of block):
// .---+---+---+---+- -+- -+- -. cksum tag: 1 be16 2 bytes
// | tag | 0 | size | cksum weight (0): 1 leb128 1 byte
// +---+---+---+---+- -+- -+- -' cksum size: 1 leb128 <=4 bytes
// | cksum | cksum cksum: 1 le32 4 bytes
// '---+---+---+---' total: <=11 bytes
//
lfs_size_t off_ = lfs_alignup(
lfsr_rbyd_eoff(rbyd) + 2+1+1+4+4 + 2+1+4+4,
lfs->cfg->prog_size);
// space for ecksum?
bool perturb = false;
if (off_ < lfs->cfg->block_size) {
// read the leading byte in case we need to perturb the next commit,
// this should hopefully stay in our cache
uint8_t e = 0;
int err = lfsr_bd_read(lfs,
rbyd->blocks[0], off_, lfs->cfg->prog_size,
&e, 1);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// we don't want the next commit to appear as valid, so we
// intentionally perturb the commit if this happens, this is
// roughly equivalent to inverting all tags' valid bits
perturb = ((e >> 7) == lfs_parity(cksum));
// calculate the erased-state checksum
uint32_t ecksum = 0;
err = lfsr_bd_cksum(lfs,
rbyd->blocks[0], off_, lfs->cfg->prog_size,
lfs->cfg->prog_size,
&ecksum);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
err = lfsr_rbyd_appendrattr_(lfs, rbyd, LFSR_RATTR_ECKSUM(
LFSR_TAG_ECKSUM, 0,
(&(lfsr_ecksum_t){
.cksize=lfs->cfg->prog_size,
.cksum=ecksum})));
if (err) {
return err;
}
// at least space for a cksum?
} else if (lfsr_rbyd_eoff(rbyd) + 2+1+4+4 <= lfs->cfg->block_size) {
// note this implicitly marks the rbyd as unerased
off_ = lfs->cfg->block_size;
// not even space for a cksum? we can't finish the commit
} else {
return LFS_ERR_RANGE;
}
// build the end-of-commit checksum tag
//
// note padding-size depends on leb-encoding depends on padding-size
// depends leb-encoding depends on... to get around this catch-22 we
// just always write a fully-expanded leb128 encoding
//
bool v = lfs_parity(rbyd->cksum) ^ lfsr_rbyd_isperturb(rbyd);
uint8_t cksum_buf[2+1+4+4];
cksum_buf[0] = (uint8_t)(LFSR_TAG_CKSUM >> 8)
// set the valid bit to the cksum parity
| ((uint8_t)v << 7);
cksum_buf[1] = (uint8_t)(LFSR_TAG_CKSUM >> 0)
// set the perturb bit so next commit is invalid
| ((uint8_t)perturb << 2)
// include the lower 2 bits of the block address to help
// with resynchronization
| (rbyd->blocks[0] & 0x3);
cksum_buf[2] = 0;
lfs_size_t padding = off_ - (lfsr_rbyd_eoff(rbyd) + 2+1+4);
cksum_buf[3] = 0x80 | (0x7f & (padding >> 0));
cksum_buf[4] = 0x80 | (0x7f & (padding >> 7));
cksum_buf[5] = 0x80 | (0x7f & (padding >> 14));
cksum_buf[6] = 0x00 | (0x7f & (padding >> 21));
// exclude the valid bit
uint32_t cksum_ = rbyd->cksum ^ ((uint32_t)v << 7);
// calculate the commit checksum
cksum_ = lfs_crc32c(cksum_, cksum_buf, 2+1+4);
// and perturb, perturbing the commit checksum avoids a perturb hole
// after the last valid bit
//
// note the odd-parity zero preserves our position in the crc32c
// ring while only changing the parity
cksum_ ^= (lfsr_rbyd_isperturb(rbyd)) ? LFS_CRC32C_ODDZERO : 0;
lfs_tole32(cksum_, &cksum_buf[2+1+4]);
// prog, when this lands on disk commit is committed
int err = lfsr_bd_prog(lfs, rbyd->blocks[0], lfsr_rbyd_eoff(rbyd),
cksum_buf, 2+1+4+4,
NULL, false);
if (err) {
return err;
}
// flush any pending progs
err = lfsr_bd_flush(lfs, NULL, false);
if (err) {
return err;
}
// update the eoff and perturb
rbyd->eoff
= ((lfs_size_t)perturb << (8*sizeof(lfs_size_t)-1))
| off_;
// revert to canonical checksum
rbyd->cksum = cksum;
#ifdef LFS_DBGRBYDCOMMITS
LFS_DEBUG("Committed rbyd 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"eoff %"PRId32", cksum %"PRIx32,
rbyd->blocks[0], lfsr_rbyd_trunk(rbyd),
rbyd->weight,
(lfsr_rbyd_eoff(rbyd) >= lfs->cfg->block_size)
? -1
: (lfs_ssize_t)lfsr_rbyd_eoff(rbyd),
rbyd->cksum);
#endif
return 0;
}
static int lfsr_rbyd_appendcksum(lfs_t *lfs, lfsr_rbyd_t *rbyd) {
// begin appending
int err = lfsr_rbyd_appendinit(lfs, rbyd);
if (err) {
return err;
}
// append checksum stuff
return lfsr_rbyd_appendcksum_(lfs, rbyd, rbyd->cksum);
}
static int lfsr_rbyd_appendrattrs(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, lfsr_srid_t start_rid, lfsr_srid_t end_rid,
const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// append each tag to the tree
for (lfs_size_t i = 0; i < rattr_count; i++) {
// treat inserts after the first tag as though they are splits,
// sequential inserts don't really make sense otherwise
if (i > 0 && lfsr_rattr_isinsert(rattrs[i])) {
rid += 1;
}
// don't write tags outside of the requested range
if (rid >= start_rid
// note the use of rid+1 and unsigned comparison here to
// treat end_rid=-1 as "unbounded" in such a way that rid=-1
// is still included
&& (lfs_size_t)(rid + 1) <= (lfs_size_t)end_rid) {
int err = lfsr_rbyd_appendrattr(lfs, rbyd,
rid - lfs_smax(start_rid, 0),
rattrs[i]);
if (err) {
return err;
}
}
// we need to make sure we keep start_rid/end_rid updated with
// weight changes
if (rid < start_rid) {
start_rid += rattrs[i].weight;
}
if (rid < end_rid) {
end_rid += rattrs[i].weight;
}
// adjust rid
rid = lfsr_rattr_nextrid(rattrs[i], rid);
}
return 0;
}
static int lfsr_rbyd_commit(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_srid_t rid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// append each tag to the tree
int err = lfsr_rbyd_appendrattrs(lfs, rbyd, rid, -1, -1,
rattrs, rattr_count);
if (err) {
return err;
}
// append a cksum, finalizing the commit
err = lfsr_rbyd_appendcksum(lfs, rbyd);
if (err) {
return err;
}
return 0;
}
// Calculate the maximum possible disk usage required by this rbyd after
// compaction. This uses a conservative estimate so the actual on-disk cost
// should be smaller.
//
// This also returns a good split_rid in case the rbyd needs to be split.
//
// TODO do we need to include commit overhead here?
static lfs_ssize_t lfsr_rbyd_estimate(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_srid_t start_rid, lfsr_srid_t end_rid,
lfsr_srid_t *split_rid_) {
// calculate dsize by starting from the outside ids and working inwards,
// this naturally gives us a split rid
//
// TODO adopt this a/b naming scheme in lfsr_rbyd_appendrattr?
lfsr_srid_t a_rid = start_rid;
lfsr_srid_t b_rid = lfs_min(rbyd->weight, end_rid);
lfs_size_t a_dsize = 0;
lfs_size_t b_dsize = 0;
lfs_size_t rbyd_dsize = 0;
while (a_rid != b_rid) {
if (a_dsize > b_dsize
// bias so lower dsize >= upper dsize
|| (a_dsize == b_dsize && a_rid > b_rid)) {
LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
LFS_SWAP(lfs_size_t, &a_dsize, &b_dsize);
}
if (a_rid > b_rid) {
a_rid -= 1;
}
lfsr_tag_t tag = 0;
lfsr_rid_t weight = 0;
lfs_size_t dsize_ = 0;
while (true) {
lfsr_srid_t rid_;
lfsr_rid_t weight_;
lfsr_data_t data;
int err = lfsr_rbyd_lookupnext(lfs, rbyd,
a_rid, tag+1,
&rid_, &tag, &weight_, &data);
if (err < 0) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
if (rid_ > a_rid+lfs_smax(weight_-1, 0)) {
break;
}
// keep track of rid and weight
a_rid = rid_;
weight += weight_;
// include the cost of this tag
dsize_ += lfs->rattr_estimate + lfsr_data_size(data);
}
if (a_rid == -1) {
rbyd_dsize += dsize_;
} else {
a_dsize += dsize_;
}
if (a_rid < b_rid) {
a_rid += 1;
} else {
a_rid -= lfs_smax(weight-1, 0);
}
}
if (split_rid_) {
*split_rid_ = a_rid;
}
return rbyd_dsize + a_dsize + b_dsize;
}
// appends a raw tag as a part of compaction, note these must
// be appended in order!
//
// also note rattr.weight here is total weight not delta weight
static int lfsr_rbyd_appendcompactrattr(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_rattr_t rattr) {
// begin appending
int err = lfsr_rbyd_appendinit(lfs, rbyd);
if (err) {
return err;
}
// write the tag
err = lfsr_rbyd_appendrattr_(lfs, rbyd, LFSR_RATTR_(
(lfsr_rbyd_isshrub(rbyd) ? LFSR_TAG_SHRUB : 0) | rattr.tag,
rattr.weight,
rattr.u, rattr.count));
if (err) {
return err;
}
return 0;
}
static int lfsr_rbyd_appendcompactrbyd(lfs_t *lfs, lfsr_rbyd_t *rbyd_,
const lfsr_rbyd_t *rbyd, lfsr_srid_t start_rid, lfsr_srid_t end_rid) {
// copy over tags in the rbyd in order
lfsr_srid_t rid = start_rid;
lfsr_tag_t tag = 0;
while (true) {
lfsr_rid_t weight;
lfsr_data_t data;
int err = lfsr_rbyd_lookupnext(lfs, rbyd,
rid, tag+1,
&rid, &tag, &weight, &data);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// end of range? note the use of rid+1 and unsigned comparison here to
// treat end_rid=-1 as "unbounded" in such a way that rid=-1 is still
// included
if ((lfs_size_t)(rid + 1) > (lfs_size_t)end_rid) {
break;
}
// write the tag
err = lfsr_rbyd_appendcompactrattr(lfs, rbyd_, LFSR_RATTR_DATA(
tag, weight, &data));
if (err) {
return err;
}
}
return 0;
}
static int lfsr_rbyd_appendcompaction(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfs_size_t off) {
// begin appending
int err = lfsr_rbyd_appendinit(lfs, rbyd);
if (err) {
return err;
}
// clamp offset to be after the revision count
off = lfs_max(off, sizeof(uint32_t));
// empty rbyd? write a null tag so our trunk can still point to something
if (lfsr_rbyd_eoff(rbyd) == off) {
err = lfsr_rbyd_appendtag(lfs, rbyd,
// mark as shrub if we are a shrub
(lfsr_rbyd_isshrub(rbyd) ? LFSR_TAG_SHRUB : 0)
| LFSR_TAG_NULL,
0,
0);
if (err) {
return err;
}
rbyd->trunk = (rbyd->trunk & LFSR_RBYD_ISSHRUB) | off;
rbyd->weight = 0;
return 0;
}
// connect every other trunk together, building layers of a perfectly
// balanced binary tree upwards until we have a single trunk
lfs_size_t layer = off;
lfsr_rid_t weight = 0;
lfsr_tag_t tag_ = 0;
while (true) {
lfs_size_t layer_ = lfsr_rbyd_eoff(rbyd);
off = layer;
while (off < layer_) {
// connect two trunks together with a new binary trunk
for (int i = 0; i < 2 && off < layer_; i++) {
lfs_size_t trunk = off;
lfsr_tag_t tag = 0;
weight = 0;
while (true) {
lfsr_tag_t tag__;
lfsr_rid_t weight__;
lfs_size_t size__;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
rbyd->blocks[0], off, layer_ - off,
&tag__, &weight__, &size__,
NULL);
if (d < 0) {
return d;
}
off += d;
// skip any data
if (!lfsr_tag_isalt(tag__)) {
off += size__;
}
// ignore shrub trunks, unless we are actually compacting
// a shrub tree
if (!lfsr_tag_isalt(tag__)
&& lfsr_tag_isshrub(tag__)
&& !lfsr_rbyd_isshrub(rbyd)) {
trunk = off;
weight = 0;
continue;
}
// keep track of trunk's trunk and weight
weight += weight__;
// keep track of the last non-null tag in our trunk.
// Because of how we construct each layer, the last
// non-null tag is the largest tag in that part of
// the tree
if (tag__ & ~LFSR_TAG_SHRUB) {
tag = tag__;
}
// did we hit a tag that terminates our trunk?
if (!lfsr_tag_isalt(tag__)) {
break;
}
}
// do we only have one trunk? we must be done
if (trunk == layer && off >= layer_) {
goto done;
}
// connect with an altle/altgt
//
// note we need to use altles for all but the last tag
// so we know the largest tag when building the next
// layer, but for that last tag we need an altgt so
// future appends maintain the balance of the tree
err = lfsr_rbyd_appendtag(lfs, rbyd,
(off < layer_)
? LFSR_TAG_ALT(
(i == 0) ? LFSR_TAG_R : LFSR_TAG_B,
LFSR_TAG_LE,
tag)
: LFSR_TAG_ALT(
LFSR_TAG_B,
LFSR_TAG_GT,
tag_),
weight,
lfsr_rbyd_eoff(rbyd) - trunk);
if (err) {
return err;
}
// keep track of the previous tag for altgts
tag_ = tag;
}
// terminate with a null tag
err = lfsr_rbyd_appendtag(lfs, rbyd,
// mark as shrub if we are a shrub
(lfsr_rbyd_isshrub(rbyd) ? LFSR_TAG_SHRUB : 0)
| LFSR_TAG_NULL,
0,
0);
if (err) {
return err;
}
}
layer = layer_;
}
done:;
// done! just need to update our trunk. Note we could have no trunks
// after compaction. Leave this to upper layers to take care of this.
rbyd->trunk = (rbyd->trunk & LFSR_RBYD_ISSHRUB) | layer;
rbyd->weight = weight;
return 0;
}
static int lfsr_rbyd_compact(lfs_t *lfs, lfsr_rbyd_t *rbyd_,
const lfsr_rbyd_t *rbyd, lfsr_srid_t start_rid, lfsr_srid_t end_rid) {
// append rbyd
int err = lfsr_rbyd_appendcompactrbyd(lfs, rbyd_,
rbyd, start_rid, end_rid);
if (err) {
return err;
}
// compact
err = lfsr_rbyd_appendcompaction(lfs, rbyd_, 0);
if (err) {
return err;
}
return 0;
}
// append a secondary "shrub" tree
static int lfsr_rbyd_appendshrub(lfs_t *lfs, lfsr_rbyd_t *rbyd,
const lfsr_shrub_t *shrub) {
// keep track of the start of the new tree
lfs_size_t off = lfsr_rbyd_eoff(rbyd);
// mark as shrub
rbyd->trunk |= LFSR_RBYD_ISSHRUB;
// compact our shrub
int err = lfsr_rbyd_appendcompactrbyd(lfs, rbyd,
shrub, -1, -1);
if (err) {
return err;
}
err = lfsr_rbyd_appendcompaction(lfs, rbyd, off);
if (err) {
return err;
}
return 0;
}
// some low-level name things
//
// names in littlefs are tuples of directory-ids + ascii/utf8 strings
// binary search an rbyd for a name, leaving the rid_/tag_/weight_/data_
// with the best matching name if not found
static lfs_scmp_t lfsr_rbyd_namelookup(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfsr_did_t did, const char *name, lfs_size_t name_len,
lfsr_srid_t *rid_,
lfsr_tag_t *tag_, lfsr_rid_t *weight_, lfsr_data_t *data_) {
// empty rbyd? leave it up to upper layers to handle this
if (rbyd->weight == 0) {
return LFS_ERR_NOENT;
}
// binary search for our name
lfsr_srid_t lower_rid = 0;
lfsr_srid_t upper_rid = rbyd->weight;
lfs_scmp_t cmp;
while (lower_rid < upper_rid) {
lfsr_tag_t tag__;
lfsr_srid_t rid__;
lfsr_rid_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, rbyd,
// lookup ~middle rid, note we may end up in the middle
// of a weighted rid with this
lower_rid + (upper_rid-1-lower_rid)/2, 0,
&rid__, &tag__, &weight__, &data__);
if (err < 0) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if we have no name, treat this rid as always lt
if (lfsr_tag_suptype(tag__) != LFSR_TAG_NAME) {
cmp = LFS_CMP_LT;
// compare names
} else {
cmp = lfsr_data_namecmp(lfs, data__, did, name, name_len);
if (cmp < 0) {
return cmp;
}
}
// bisect search space
if (cmp > LFS_CMP_EQ) {
upper_rid = rid__ - (weight__-1);
// only keep track of best-match rids > our target if we haven't
// seen an rid < our target
if (lower_rid == 0) {
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
}
} else if (cmp < LFS_CMP_EQ) {
lower_rid = rid__ + 1;
// keep track of best-matching rid < our target
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
} else {
// found a match?
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return LFS_CMP_EQ;
}
}
// no match, return if found name was lt/gt expect
//
// this will always be lt unless all rids are gt
return (lower_rid == 0) ? LFS_CMP_GT : LFS_CMP_LT;
}
/// B-tree operations ///
// create an empty btree
static void lfsr_btree_init(lfsr_btree_t *btree) {
btree->weight = 0;
btree->blocks[0] = -1;
btree->trunk = 0;
}
// convenience operations
static inline void lfsr_btree_claim(lfsr_btree_t *btree) {
lfsr_rbyd_claim(btree);
}
static inline int lfsr_btree_cmp(
const lfsr_btree_t *a,
const lfsr_btree_t *b) {
return lfsr_rbyd_cmp(a, b);
}
// branch on-disk encoding
static lfsr_data_t lfsr_data_frombranch(const lfsr_rbyd_t *branch,
uint8_t buffer[static LFSR_BRANCH_DSIZE]) {
// block should not exceed 31-bits
LFS_ASSERT(branch->blocks[0] <= 0x7fffffff);
// trunk should not exceed 28-bits
LFS_ASSERT(lfsr_rbyd_trunk(branch) <= 0x0fffffff);
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(branch->blocks[0], &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
d_ = lfs_toleb128(lfsr_rbyd_trunk(branch), &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
lfs_tole32(branch->cksum, &buffer[d]);
d += 4;
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readbranch(lfs_t *lfs,
lfsr_data_t *data, lfsr_bid_t weight,
lfsr_rbyd_t *branch) {
// setting off to 0 here will trigger asserts if we try to append
// without fetching first
branch->eoff = 0;
branch->weight = weight;
int err = lfsr_data_readleb128(lfs, data, &branch->blocks[0]);
if (err) {
return err;
}
err = lfsr_data_readlleb128(lfs, data, &branch->trunk);
if (err) {
return err;
}
err = lfsr_data_readle32(lfs, data, &branch->cksum);
if (err) {
return err;
}
return 0;
}
// needed in lfsr_branch_fetch
#ifdef LFS_CKFETCHES
static inline bool lfsr_m_isckfetches(uint32_t flags);
#endif
static int lfsr_branch_fetch(lfs_t *lfs, lfsr_rbyd_t *branch,
lfs_block_t block, lfs_size_t trunk, lfsr_bid_t weight,
uint32_t cksum) {
(void)lfs;
branch->blocks[0] = block;
branch->trunk = trunk;
branch->weight = weight;
branch->eoff = 0;
branch->cksum = cksum;
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)) {
int err = lfsr_rbyd_fetchck(lfs, branch,
branch->blocks[0], lfsr_rbyd_trunk(branch),
branch->cksum);
if (err) {
return err;
}
LFS_ASSERT(branch->weight == weight);
}
#endif
return 0;
}
static int lfsr_data_fetchbranch(lfs_t *lfs,
lfsr_data_t *data, lfsr_bid_t weight,
lfsr_rbyd_t *branch) {
// decode branch and fetch
int err = lfsr_data_readbranch(lfs, data, weight,
branch);
if (err) {
return err;
}
return lfsr_branch_fetch(lfs, branch,
branch->blocks[0], branch->trunk, branch->weight,
branch->cksum);
}
// btree on-disk encoding
//
// this is the same as the branch on-disk econding, but prefixed with the
// btree's weight
static lfsr_data_t lfsr_data_frombtree(const lfsr_btree_t *btree,
uint8_t buffer[static LFSR_BTREE_DSIZE]) {
// weight should not exceed 31-bits
LFS_ASSERT(btree->weight <= 0x7fffffff);
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(btree->weight, &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
lfsr_data_t data = lfsr_data_frombranch(btree, &buffer[d]);
d += lfsr_data_size(data);
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readbtree(lfs_t *lfs, lfsr_data_t *data,
lfsr_btree_t *btree) {
lfsr_bid_t weight;
int err = lfsr_data_readleb128(lfs, data, &weight);
if (err) {
return err;
}
err = lfsr_data_readbranch(lfs, data, weight, btree);
if (err) {
return err;
}
return 0;
}
// core btree operations
static int lfsr_btree_fetch(lfs_t *lfs, lfsr_btree_t *btree,
lfs_block_t block, lfs_size_t trunk, lfsr_bid_t weight,
uint32_t cksum) {
// btree/branch fetch really are the same once we know the weight
int err = lfsr_branch_fetch(lfs, btree,
block, trunk, weight,
cksum);
if (err) {
return err;
}
#ifdef LFS_DBGBTREEFETCHES
LFS_DEBUG("Fetched btree 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"cksum %"PRIx32,
btree->blocks[0], lfsr_rbyd_trunk(btree),
btree->weight,
btree->cksum);
#endif
return 0;
}
static int lfsr_data_fetchbtree(lfs_t *lfs, lfsr_data_t *data,
lfsr_btree_t *btree) {
// decode btree and fetch
int err = lfsr_data_readbtree(lfs, data,
btree);
if (err) {
return err;
}
return lfsr_btree_fetch(lfs, btree,
btree->blocks[0], btree->trunk, btree->weight,
btree->cksum);
}
// lookup rbyd/rid containing a given bid
static int lfsr_btree_lookupleaf(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_rbyd_t *rbyd_, lfsr_srid_t *rid_,
lfsr_tag_t *tag_, lfsr_bid_t *weight_, lfsr_data_t *data_) {
// descend down the btree looking for our bid
*rbyd_ = *btree;
lfsr_srid_t rid = bid;
while (true) {
// each branch is a pair of optional name + on-disk structure
// lookup our bid in the rbyd
lfsr_srid_t rid__;
lfsr_tag_t tag__;
lfsr_rid_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, rbyd_, rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
return err;
}
// if we found a bname, lookup the branch
if (tag__ == LFSR_TAG_BNAME) {
err = lfsr_rbyd_lookup(lfs, rbyd_, rid__, LFSR_TAG_BRANCH,
&tag__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// found another branch
if (tag__ == LFSR_TAG_BRANCH) {
// adjust rid with subtree's weight
rid -= (rid__ - (weight__-1));
// fetch the next branch
err = lfsr_data_fetchbranch(lfs, &data__, weight__,
rbyd_);
if (err) {
return err;
}
// found our bid
} else {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = bid + (rid__ - rid);
}
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return 0;
}
}
}
// non-leaf lookups discard the rbyd info, which can be a bit more
// convenient, but may make commits more costly
static int lfsr_btree_lookupnext(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_bid_t *weight_,
lfsr_data_t *data_) {
lfsr_rbyd_t rbyd;
return lfsr_btree_lookupleaf(lfs, btree, bid,
bid_, &rbyd, NULL, tag_, weight_, data_);
}
// lfsr_btree_lookup assumes a known bid, matching lfsr_rbyd_lookup's
// behavior, if you don't care about the exact bid either first call
// lfsr_btree_lookupnext, or lfsr_btree_lookupleaf + lfsr_rbyd_lookup
static int lfsr_btree_lookup(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_bid_t bid, lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
// lookup rbyd in btree
lfsr_bid_t bid__;
lfsr_rbyd_t rbyd__;
lfsr_srid_t rid__;
int err = lfsr_btree_lookupleaf(lfs, btree, bid,
&bid__, &rbyd__, &rid__, NULL, NULL, NULL);
if (err) {
return err;
}
// lookup finds the next-smallest bid, all we need to do is fail if it
// picks up the wrong bid
if (bid__ != bid) {
return LFS_ERR_NOENT;
}
// lookup tag in rbyd
return lfsr_rbyd_lookup(lfs, &rbyd__, rid__, tag,
tag_, data_);
}
// TODO should lfsr_btree_lookupnext/lfsr_btree_parent be deduplicated?
static int lfsr_btree_parent(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_bid_t bid, const lfsr_rbyd_t *child,
lfsr_rbyd_t *rbyd_, lfsr_srid_t *rid_) {
// we should only call this when we actually have parents
LFS_ASSERT(bid < (lfsr_bid_t)btree->weight);
LFS_ASSERT(lfsr_rbyd_cmp(btree, child) != 0);
// descend down the btree looking for our rid
*rbyd_ = *btree;
lfsr_srid_t rid = bid;
while (true) {
// each branch is a pair of optional name + on-disk structure
lfsr_srid_t rid__;
lfsr_tag_t tag__;
lfsr_rid_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, rbyd_, rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if we found a bname, lookup the branch
if (tag__ == LFSR_TAG_BNAME) {
err = lfsr_rbyd_lookup(lfs, rbyd_, rid__, LFSR_TAG_BRANCH,
&tag__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// didn't find our child?
if (tag__ != LFSR_TAG_BRANCH) {
return LFS_ERR_NOENT;
}
// adjust rid with subtree's weight
rid -= (rid__ - (weight__-1));
// fetch the next branch
lfsr_rbyd_t child_;
err = lfsr_data_readbranch(lfs, &data__, weight__, &child_);
if (err) {
return err;
}
// found our child?
if (lfsr_rbyd_cmp(&child_, child) == 0) {
// TODO how many of these should be conditional?
if (rid_) {
*rid_ = rid__;
}
return 0;
}
err = lfsr_branch_fetch(lfs, rbyd_,
child_.blocks[0], child_.trunk, child_.weight,
child_.cksum);
if (err) {
return err;
}
}
}
// extra state needed for non-terminating lfsr_btree_commit_ calls
typedef struct lfsr_bctx {
lfsr_rattr_t rattrs[4];
lfsr_data_t split_name;
uint8_t buf[2*LFSR_BRANCH_DSIZE];
} lfsr_bctx_t;
// needed in lfsr_btree_commit_
static inline uint32_t lfsr_rev_btree(lfs_t *lfs);
// core btree algorithm
//
// this commits up to the root, but stops if:
// 1. we need a new root
// 2. we have a shrub root
//
// ---
//
// note! all non-bid-0 name updates must be via splits!
//
// This is because our btrees contain vestigial names, i.e. our inner
// nodes may contain names no longer in the tree. This simplifies
// lfsr_btree_commit_, but means insert-before-bid+1 is _not_ the same
// as insert-after-bid when named btrees are involved. If you try this
// it _will not_ work and if try to make it work you _will_ cry:
//
// .-----f-----. insert-after-d .-------f-----.
// .-b--. .--j-. => .-b---. .--j-.
// | .-. .-. | | .---. .-. |
// a c d h i k a c d e h i k
// ^
// insert-before-h
// => .-----f-------.
// .-b--. .---j-.
// | .-. .---. |
// a c d g h i k
// ^
//
// The problem is that lfsr_btree_commit_ needs to find the same leaf
// rbyd as lfsr_btree_namelookup, and potentially insert-before the
// first rid or insert-after the last rid.
//
// Instead of separate insert-before/after flags, we make the first tag
// in a commit insert-before, and all following non-grow tags
// insert-after (splits).
//
static int lfsr_btree_commit_(lfs_t *lfs, lfsr_btree_t *btree,
lfsr_bctx_t *bctx,
lfsr_bid_t *bid,
const lfsr_rattr_t **rattrs, lfs_size_t *rattr_count) {
lfsr_bid_t bid_ = *bid;
LFS_ASSERT(bid_ <= (lfsr_bid_t)btree->weight);
const lfsr_rattr_t *rattrs_ = *rattrs;
lfs_size_t rattr_count_ = *rattr_count;
// lookup which leaf our bid resides
//
// for lfsr_btree_commit_ operations to work out, we need to
// limit our bid to an rid in the tree, which is what this min
// is doing
lfsr_rbyd_t child = *btree;
lfsr_srid_t rid_ = bid_;
if (btree->weight > 0) {
lfsr_srid_t rid__;
int err = lfsr_btree_lookupleaf(lfs, btree,
lfs_min(bid_, btree->weight-1),
&bid_, &child, &rid__, NULL, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// adjust rid
rid_ -= (bid_-rid__);
}
// tail-recursively commit to btree
while (true) {
// we will always need our parent, so go ahead and find it
lfsr_rbyd_t parent = {.trunk=0, .weight=0};
lfsr_srid_t pid = 0;
// are we root?
if (!lfsr_rbyd_trunk(&child)
|| child.blocks[0] == btree->blocks[0]) {
// new root? shrub root? yield the final root commit to
// higher-level btree/bshrub logic
if (!lfsr_rbyd_trunk(&child)
|| lfsr_rbyd_isshrub(btree)) {
*bid = rid_;
*rattrs = rattrs_;
*rattr_count = rattr_count_;
return (!lfsr_rbyd_trunk(&child)) ? LFS_ERR_RANGE : 0;
}
// mark btree as unerased in case of failure, our btree rbyd and
// root rbyd can diverge if there's a split, but we would have
// marked the old root as unerased earlier anyways
lfsr_btree_claim(btree);
} else {
int err = lfsr_btree_parent(lfs, btree, bid_, &child,
&parent, &pid);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// fetch our rbyd so we can mutate it
//
// note that some paths lead this to being a newly allocated rbyd,
// these will fail to fetch so we need to check that this rbyd is
// unfetched
//
// a funny benefit is we cache the root of our btree this way
if (!lfsr_rbyd_isfetched(&child)) {
int err = lfsr_rbyd_fetchck(lfs, &child,
child.blocks[0], lfsr_rbyd_trunk(&child),
child.cksum);
if (err) {
return err;
}
}
// is rbyd erased? can we sneak our commit into any remaining
// erased bytes? note that the btree trunk field prevents this from
// interacting with other references to the rbyd
lfsr_rbyd_t child_ = child;
int err = lfsr_rbyd_commit(lfs, &child_, rid_,
rattrs_, rattr_count_);
if (err) {
if (err == LFS_ERR_RANGE || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
goto commit;
compact:;
// estimate our compacted size
lfsr_srid_t split_rid;
lfs_ssize_t estimate = lfsr_rbyd_estimate(lfs, &child, -1, -1,
&split_rid);
if (estimate < 0) {
return estimate;
}
// are we too big? need to split?
if ((lfs_size_t)estimate > lfs->cfg->block_size/2) {
// need to split
goto split;
}
// before we compact, can we merge with our siblings?
lfsr_rbyd_t sibling;
if ((lfs_size_t)estimate <= lfs->cfg->block_size/4
// no parent? can't merge
&& lfsr_rbyd_trunk(&parent)) {
// try the right sibling
if (pid+1 < (lfsr_srid_t)parent.weight) {
// try looking up the sibling
lfsr_srid_t sibling_rid;
lfsr_tag_t sibling_tag;
lfsr_rid_t sibling_weight;
lfsr_data_t sibling_data;
err = lfsr_rbyd_lookupnext(lfs, &parent, pid+1, 0,
&sibling_rid, &sibling_tag, &sibling_weight,
&sibling_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if we found a bname, lookup the branch
if (sibling_tag == LFSR_TAG_BNAME) {
err = lfsr_rbyd_lookup(lfs, &parent,
sibling_rid, LFSR_TAG_BRANCH,
&sibling_tag, &sibling_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
LFS_ASSERT(sibling_tag == LFSR_TAG_BRANCH);
err = lfsr_data_fetchbranch(lfs, &sibling_data, sibling_weight,
&sibling);
if (err) {
return err;
}
// estimate if our sibling will fit
lfs_ssize_t sibling_estimate = lfsr_rbyd_estimate(lfs,
&sibling, -1, -1,
NULL);
if (sibling_estimate < 0) {
return sibling_estimate;
}
// fits? try to merge
if ((lfs_size_t)(estimate + sibling_estimate)
< lfs->cfg->block_size/2) {
goto merge;
}
}
// try the left sibling
if (pid-(lfsr_srid_t)child.weight >= 0) {
// try looking up the sibling
lfsr_srid_t sibling_rid;
lfsr_tag_t sibling_tag;
lfsr_rid_t sibling_weight;
lfsr_data_t sibling_data;
err = lfsr_rbyd_lookupnext(lfs, &parent, pid-child.weight, 0,
&sibling_rid, &sibling_tag, &sibling_weight,
&sibling_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if we found a bname, lookup the branch
if (sibling_tag == LFSR_TAG_BNAME) {
err = lfsr_rbyd_lookup(lfs, &parent,
sibling_rid, LFSR_TAG_BRANCH,
&sibling_tag, &sibling_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
LFS_ASSERT(sibling_tag == LFSR_TAG_BRANCH);
err = lfsr_data_fetchbranch(lfs, &sibling_data, sibling_weight,
&sibling);
if (err) {
return err;
}
// estimate if our sibling will fit
lfs_ssize_t sibling_estimate = lfsr_rbyd_estimate(lfs,
&sibling, -1, -1,
NULL);
if (sibling_estimate < 0) {
return sibling_estimate;
}
// fits? try to merge
if ((lfs_size_t)(estimate + sibling_estimate)
< lfs->cfg->block_size/2) {
// if we're merging our left sibling, swap our rbyds
// so our sibling is on the right
bid_ -= sibling.weight;
rid_ += sibling.weight;
pid -= child.weight;
child_ = sibling;
sibling = child;
child = child_;
goto merge;
}
}
}
relocate:;
// allocate a new rbyd
err = lfsr_rbyd_alloc(lfs, &child_);
if (err) {
return err;
}
#if defined(LFS_REVDBG) || defined(LFS_REVNOISE)
// append a revision count?
err = lfsr_rbyd_appendrev(lfs, &child_, lfsr_rev_btree(lfs));
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
#endif
// try to compact
err = lfsr_rbyd_compact(lfs, &child_, &child, -1, -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// append any pending rattrs, it's up to upper
// layers to make sure these always fit
err = lfsr_rbyd_commit(lfs, &child_, rid_,
rattrs_, rattr_count_);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
goto commit;
split:;
// we should have something to split here
LFS_ASSERT(split_rid > 0
&& split_rid < (lfsr_srid_t)child.weight);
split_relocate_l:;
// allocate a new rbyd
err = lfsr_rbyd_alloc(lfs, &child_);
if (err) {
return err;
}
#if defined(LFS_REVDBG) || defined(LFS_REVNOISE)
// append a revision count?
err = lfsr_rbyd_appendrev(lfs, &child_, lfsr_rev_btree(lfs));
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_l;
}
return err;
}
#endif
// copy over tags < split_rid
err = lfsr_rbyd_compact(lfs, &child_, &child, -1, split_rid);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_l;
}
return err;
}
// append pending rattrs < split_rid
//
// upper layers should make sure this can't fail by limiting the
// maximum commit size
err = lfsr_rbyd_appendrattrs(lfs, &child_, rid_, -1, split_rid,
rattrs_, rattr_count_);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_l;
}
return err;
}
// finalize commit
err = lfsr_rbyd_appendcksum(lfs, &child_);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_l;
}
return err;
}
split_relocate_r:;
// allocate a sibling
err = lfsr_rbyd_alloc(lfs, &sibling);
if (err) {
return err;
}
#if defined(LFS_REVDBG) || defined(LFS_REVNOISE)
// append a revision count?
err = lfsr_rbyd_appendrev(lfs, &sibling, lfsr_rev_btree(lfs));
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_r;
}
return err;
}
#endif
// copy over tags >= split_rid
err = lfsr_rbyd_compact(lfs, &sibling, &child, split_rid, -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_r;
}
return err;
}
// append pending rattrs >= split_rid
//
// upper layers should make sure this can't fail by limiting the
// maximum commit size
err = lfsr_rbyd_appendrattrs(lfs, &sibling, rid_, split_rid, -1,
rattrs_, rattr_count_);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_r;
}
return err;
}
// finalize commit
err = lfsr_rbyd_appendcksum(lfs, &sibling);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate_r;
}
return err;
}
// did one of our siblings drop to zero? yes this can happen! revert
// to a normal commit in that case
if (child_.weight == 0 || sibling.weight == 0) {
if (child_.weight == 0) {
child_ = sibling;
}
goto commit;
}
// lookup first name in sibling to use as the split name
//
// note we need to do this after playing out pending rattrs in case
// they introduce a new name!
lfsr_tag_t split_tag;
err = lfsr_rbyd_lookupnext(lfs, &sibling, 0, 0,
NULL, &split_tag, NULL, &bctx->split_name);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// prepare commit to parent, tail recursing upwards
LFS_ASSERT(child_.weight > 0);
LFS_ASSERT(sibling.weight > 0);
rattr_count_ = 0;
// new root?
if (!lfsr_rbyd_trunk(&parent)) {
lfsr_data_t branch_l = lfsr_data_frombranch(
&child_, &bctx->buf[0*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, +child_.weight,
branch_l.u.buffer, lfsr_data_size(branch_l));
lfsr_data_t branch_r = lfsr_data_frombranch(
&sibling, &bctx->buf[1*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, +sibling.weight,
branch_r.u.buffer, lfsr_data_size(branch_r));
if (lfsr_tag_suptype(split_tag) == LFSR_TAG_NAME) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR_DATA(
LFSR_TAG_BNAME, 0,
&bctx->split_name);
}
// split root?
} else {
bid_ -= pid - (child.weight-1);
lfsr_data_t branch_l = lfsr_data_frombranch(
&child_, &bctx->buf[0*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, 0,
branch_l.u.buffer, lfsr_data_size(branch_l));
if (child_.weight != child.weight) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR(
LFSR_TAG_GROW, -child.weight + child_.weight);
}
lfsr_data_t branch_r = lfsr_data_frombranch(
&sibling, &bctx->buf[1*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, +sibling.weight,
branch_r.u.buffer, lfsr_data_size(branch_r));
if (lfsr_tag_suptype(split_tag) == LFSR_TAG_NAME) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR_DATA(
LFSR_TAG_BNAME, 0,
&bctx->split_name);
}
}
rattrs_ = bctx->rattrs;
child = parent;
rid_ = pid;
continue;
merge:;
merge_relocate:;
// allocate a new rbyd
err = lfsr_rbyd_alloc(lfs, &child_);
if (err) {
return err;
}
#if defined(LFS_REVDBG) || defined(LFS_REVNOISE)
// append a revision count?
err = lfsr_rbyd_appendrev(lfs, &child_, lfsr_rev_btree(lfs));
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto merge_relocate;
}
return err;
}
#endif
// merge the siblings together
err = lfsr_rbyd_appendcompactrbyd(lfs, &child_, &child, -1, -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto merge_relocate;
}
return err;
}
err = lfsr_rbyd_appendcompactrbyd(lfs, &child_, &sibling, -1, -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto merge_relocate;
}
return err;
}
err = lfsr_rbyd_appendcompaction(lfs, &child_, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto merge_relocate;
}
return err;
}
// append any pending rattrs, it's up to upper
// layers to make sure these always fit
err = lfsr_rbyd_commit(lfs, &child_, rid_,
rattrs_, rattr_count_);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto merge_relocate;
}
return err;
}
// we must have a parent at this point, but is our parent the root
// and is the root degenerate?
LFS_ASSERT(lfsr_rbyd_trunk(&parent));
if (child.weight+sibling.weight == btree->weight) {
// collapse the root, decreasing the height of the tree
*btree = child_;
// no new root needed
*rattr_count = 0;
return 0;
}
// prepare commit to parent, tail recursing upwards
LFS_ASSERT(child_.weight > 0);
rattr_count_ = 0;
// build attr list
bid_ -= pid - (child.weight-1);
bctx->rattrs[rattr_count_++] = LFSR_RATTR(
LFSR_TAG_RM, -sibling.weight);
lfsr_data_t branch = lfsr_data_frombranch(
&child_, &bctx->buf[0*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, 0,
branch.u.buffer, lfsr_data_size(branch));
if (child_.weight != child.weight) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR(
LFSR_TAG_GROW, -child.weight + child_.weight);
}
rattrs_ = bctx->rattrs;
child = parent;
rid_ = pid + sibling.weight;
continue;
commit:;
// done?
if (!lfsr_rbyd_trunk(&parent)) {
// update the root
*btree = child_;
// no new root needed
*rattr_count = 0;
return 0;
}
// is our parent the root and is the root degenerate?
if (child.weight == btree->weight) {
// collapse the root, decreasing the height of the tree
*btree = child_;
// no new root needed
*rattr_count = 0;
return 0;
}
// prepare commit to parent, tail recursing upwards
//
// note that since we defer merges to compaction time, we can
// end up removing an rbyd here
rattr_count_ = 0;
bid_ -= pid - (child.weight-1);
if (child_.weight == 0) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR(
LFSR_TAG_RM, -child.weight);
} else {
lfsr_data_t branch = lfsr_data_frombranch(
&child_, &bctx->buf[0*LFSR_BRANCH_DSIZE]);
bctx->rattrs[rattr_count_++] = LFSR_RATTR_BUF(
LFSR_TAG_BRANCH, 0,
branch.u.buffer, lfsr_data_size(branch));
if (child_.weight != child.weight) {
bctx->rattrs[rattr_count_++] = LFSR_RATTR(
LFSR_TAG_GROW, -child.weight + child_.weight);
}
}
rattrs_ = bctx->rattrs;
child = parent;
rid_ = pid;
continue;
}
}
// commit/alloc a new btree root
static int lfsr_btree_commitroot_(lfs_t *lfs, lfsr_btree_t *btree,
bool split,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
relocate:;
lfsr_rbyd_t rbyd_;
int err = lfsr_rbyd_alloc(lfs, &rbyd_);
if (err) {
return err;
}
#if defined(LFS_REVDBG) || defined(LFS_REVNOISE)
// append a revision count?
err = lfsr_rbyd_appendrev(lfs, &rbyd_, lfsr_rev_btree(lfs));
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
#endif
// bshrubs may call this just to migrate rattrs to a btree
if (!split) {
err = lfsr_rbyd_compact(lfs, &rbyd_, btree, -1, -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
err = lfsr_rbyd_commit(lfs, &rbyd_, bid, rattrs, rattr_count);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// update the root
*btree = rbyd_;
return 0;
}
// commit to a btree, this is atomic
static int lfsr_btree_commit(lfs_t *lfs, lfsr_btree_t *btree,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// try to commit to the btree
lfsr_bctx_t bctx;
int err = lfsr_btree_commit_(lfs, btree, &bctx,
&bid, &rattrs, &rattr_count);
if (err && err != LFS_ERR_RANGE) {
return err;
}
// needs a new root?
if (err == LFS_ERR_RANGE) {
LFS_ASSERT(rattr_count > 0);
err = lfsr_btree_commitroot_(lfs, btree, true,
bid, rattrs, rattr_count);
if (err) {
return err;
}
}
LFS_ASSERT(lfsr_rbyd_trunk(btree));
#ifdef LFS_DBGBTREECOMMITS
LFS_DEBUG("Committed btree 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"cksum %"PRIx32,
btree->blocks[0], lfsr_rbyd_trunk(btree),
btree->weight,
btree->cksum);
#endif
return 0;
}
// lookup in a btree by name
static lfs_scmp_t lfsr_btree_namelookupleaf(lfs_t *lfs,
const lfsr_btree_t *btree,
lfsr_did_t did, const char *name, lfs_size_t name_len,
lfsr_bid_t *bid_, lfsr_rbyd_t *rbyd_, lfsr_srid_t *rid_,
lfsr_tag_t *tag_, lfsr_bid_t *weight_, lfsr_data_t *data_) {
// an empty tree?
if (btree->weight == 0) {
return LFS_ERR_NOENT;
}
// descend down the btree looking for our name
*rbyd_ = *btree;
lfsr_bid_t bid = 0;
while (true) {
// each branch is a pair of optional name + on-disk structure
// lookup our name in the rbyd via binary search
lfsr_srid_t rid__;
lfsr_tag_t tag__;
lfsr_rid_t weight__;
lfsr_data_t data__;
lfs_scmp_t cmp = lfsr_rbyd_namelookup(lfs, rbyd_,
did, name, name_len,
&rid__, &tag__, &weight__, &data__);
if (cmp < 0) {
LFS_ASSERT(cmp != LFS_ERR_NOENT);
return cmp;
}
// if we found a bname, lookup the branch
if (tag__ == LFSR_TAG_BNAME) {
int err = lfsr_rbyd_lookup(lfs, rbyd_, rid__,
LFSR_TAG_MASK8 | LFSR_TAG_STRUCT,
&tag__, &data__);
if (err < 0) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// found another branch
if (tag__ == LFSR_TAG_BRANCH) {
// update our bid
bid += rid__ - (weight__-1);
// fetch the next branch
int err = lfsr_data_fetchbranch(lfs, &data__, weight__,
rbyd_);
if (err < 0) {
return err;
}
// found our rid
} else {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = bid + rid__;
}
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return cmp;
}
}
}
static lfs_scmp_t lfsr_btree_namelookup(lfs_t *lfs,
const lfsr_btree_t *btree,
lfsr_did_t did, const char *name, lfs_size_t name_len,
lfsr_bid_t *bid_,
lfsr_tag_t *tag_, lfsr_bid_t *weight_, lfsr_data_t *data_) {
lfsr_rbyd_t rbyd;
return lfsr_btree_namelookupleaf(lfs, btree,
did, name, name_len,
bid_, &rbyd, NULL, tag_, weight_, data_);
}
// incremental btree traversal
//
// note this is different from iteration, iteration should use
// lfsr_btree_lookupnext, traversal includes inner btree nodes
static void lfsr_btraversal_init(lfsr_btraversal_t *bt) {
bt->bid = 0;
bt->branch = NULL;
bt->rid = 0;
}
static int lfsr_btree_traverse(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_btraversal_t *bt,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_data_t *data_) {
// explicitly traverse the root even if weight=0
if (!bt->branch) {
bt->branch = btree;
bt->rid = bt->bid;
// traverse the root
if (bt->bid == 0
// unless we don't even have a root yet
&& lfsr_rbyd_trunk(btree) != 0
// or are a shrub
&& !lfsr_rbyd_isshrub(btree)) {
if (bid_) {
*bid_ = btree->weight-1;
}
if (tag_) {
*tag_ = LFSR_TAG_BRANCH;
}
if (data_) {
data_->u.buffer = (const uint8_t*)bt->branch;
}
return 0;
}
}
// need to restart from the root?
if (bt->rid >= (lfsr_srid_t)bt->branch->weight) {
bt->branch = btree;
bt->rid = bt->bid;
}
// descend down the tree
while (true) {
lfsr_srid_t rid__;
lfsr_tag_t tag__;
lfsr_rid_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, bt->branch, bt->rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
return err;
}
// if we found a bname, lookup the branch
if (tag__ == LFSR_TAG_BNAME) {
err = lfsr_rbyd_lookup(lfs, bt->branch, rid__, LFSR_TAG_BRANCH,
&tag__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// found another branch
if (tag__ == LFSR_TAG_BRANCH) {
// adjust rid with subtree's weight
bt->rid -= (rid__ - (weight__-1));
// fetch the next branch
err = lfsr_data_fetchbranch(lfs, &data__, weight__,
&bt->rbyd);
if (err) {
return err;
}
bt->branch = &bt->rbyd;
// return inner btree nodes if this is the first time we've
// seen them
if (bt->rid == 0) {
if (bid_) {
*bid_ = bt->bid + (rid__ - bt->rid);
}
if (tag_) {
*tag_ = LFSR_TAG_BRANCH;
}
if (data_) {
data_->u.buffer = (const uint8_t*)bt->branch;
}
return 0;
}
// found our bid
} else {
// move on to the next rid
//
// note this effectively traverses a full leaf without redoing
// the btree walk
lfsr_bid_t bid__ = bt->bid + (rid__ - bt->rid);
bt->bid = bid__ + 1;
bt->rid = rid__ + 1;
if (bid_) {
*bid_ = bid__;
}
if (tag_) {
*tag_ = tag__;
}
if (data_) {
*data_ = data__;
}
return 0;
}
}
}
/// B-shrub operations ///
// shrub things
// helper functions
static inline bool lfsr_shrub_isshrub(const lfsr_shrub_t *shrub) {
return lfsr_rbyd_isshrub(shrub);
}
static inline lfs_size_t lfsr_shrub_trunk(const lfsr_shrub_t *shrub) {
return lfsr_rbyd_trunk(shrub);
}
static inline int lfsr_shrub_cmp(
const lfsr_shrub_t *a,
const lfsr_shrub_t *b) {
return lfsr_rbyd_cmp(a, b);
}
// shrub on-disk encoding
static lfsr_data_t lfsr_data_fromshrub(const lfsr_shrub_t *shrub,
uint8_t buffer[static LFSR_SHRUB_DSIZE]) {
// shrub trunks should never be null
LFS_ASSERT(lfsr_shrub_trunk(shrub) != 0);
// weight should not exceed 31-bits
LFS_ASSERT(shrub->weight <= 0x7fffffff);
// trunk should not exceed 28-bits
LFS_ASSERT(lfsr_shrub_trunk(shrub) <= 0x0fffffff);
lfs_ssize_t d = 0;
// just write the trunk and weight, the rest of the rbyd is contextual
lfs_ssize_t d_ = lfs_toleb128(shrub->weight, &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
d_ = lfs_toleb128(lfsr_shrub_trunk(shrub),
&buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readshrub(lfs_t *lfs, lfsr_data_t *data,
const lfsr_mdir_t *mdir,
lfsr_shrub_t *shrub) {
// copy the mdir block
shrub->blocks[0] = mdir->rbyd.blocks[0];
// force estimate recalculation if we write to this shrub
shrub->eoff = -1;
int err = lfsr_data_readleb128(lfs, data, &shrub->weight);
if (err) {
return err;
}
err = lfsr_data_readlleb128(lfs, data, &shrub->trunk);
if (err) {
return err;
}
// shrub trunks should never be null
LFS_ASSERT(lfsr_shrub_trunk(shrub));
// set the shrub bit in our trunk
shrub->trunk |= LFSR_RBYD_ISSHRUB;
return 0;
}
// needed in lfsr_shrub_estimate
static inline bool lfsr_o_isbshrub(uint32_t flags);
// these are used in mdir commit/compaction
static lfs_ssize_t lfsr_shrub_estimate(lfs_t *lfs,
const lfsr_shrub_t *shrub) {
// only include the last reference
const lfsr_shrub_t *last = NULL;
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
&& lfsr_shrub_cmp(
&((lfsr_bshrub_t*)o)->shrub,
shrub) == 0) {
last = &((lfsr_bshrub_t*)o)->shrub;
}
}
if (last && shrub != last) {
return 0;
}
return lfsr_rbyd_estimate(lfs, shrub, -1, -1,
NULL);
}
static int lfsr_shrub_compact(lfs_t *lfs, lfsr_rbyd_t *rbyd_,
lfsr_shrub_t *shrub_, const lfsr_shrub_t *shrub) {
// save our current trunk/weight
lfs_size_t trunk = rbyd_->trunk;
lfsr_srid_t weight = rbyd_->weight;
// compact our bshrub
int err = lfsr_rbyd_appendshrub(lfs, rbyd_, shrub);
if (err) {
return err;
}
// stage any opened shrubs with their new location so we can
// update these later if our commit is a success
//
// this should include our current bshrub
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
&& lfsr_shrub_cmp(
&((lfsr_bshrub_t*)o)->shrub,
shrub) == 0) {
((lfsr_bshrub_t*)o)->shrub_.blocks[0] = rbyd_->blocks[0];
((lfsr_bshrub_t*)o)->shrub_.trunk = rbyd_->trunk;
((lfsr_bshrub_t*)o)->shrub_.weight = rbyd_->weight;
}
}
// revert rbyd trunk/weight
shrub_->blocks[0] = rbyd_->blocks[0];
shrub_->trunk = rbyd_->trunk;
shrub_->weight = rbyd_->weight;
rbyd_->trunk = trunk;
rbyd_->weight = weight;
return 0;
}
// this is needed to sneak shrub commits into mdir commits
typedef struct lfsr_shrubcommit {
lfsr_bshrub_t *bshrub;
lfsr_srid_t rid;
const lfsr_rattr_t *rattrs;
lfs_size_t rattr_count;
} lfsr_shrubcommit_t;
static int lfsr_shrub_commit(lfs_t *lfs, lfsr_rbyd_t *rbyd_,
lfsr_shrub_t *shrub, lfsr_srid_t rid,
const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// swap out our trunk/weight temporarily, note we're
// operating on a copy so if this fails we shouldn't mess
// things up too much
//
// it is important that these rbyds share eoff/cksum/etc
lfs_size_t trunk = rbyd_->trunk;
lfsr_srid_t weight = rbyd_->weight;
rbyd_->trunk = shrub->trunk;
rbyd_->weight = shrub->weight;
// append any bshrub attributes
int err = lfsr_rbyd_appendrattrs(lfs, rbyd_, rid, -1, -1,
rattrs, rattr_count);
if (err) {
return err;
}
// restore mdir to the main trunk/weight
shrub->trunk = rbyd_->trunk;
shrub->weight = rbyd_->weight;
rbyd_->trunk = trunk;
rbyd_->weight = weight;
return 0;
}
// ok, actual bshrub things
// create a non-existant bshrub
static void lfsr_bshrub_init(lfsr_bshrub_t *bshrub) {
// set up a null bshrub
bshrub->shrub.weight = 0;
bshrub->shrub.blocks[0] = -1;
bshrub->shrub.trunk = 0;
// force estimate recalculation
bshrub->shrub.eoff = -1;
}
static inline bool lfsr_bshrub_isbnull(const lfsr_bshrub_t *bshrub) {
return !bshrub->shrub.trunk;
}
static inline bool lfsr_bshrub_isbshrub(const lfsr_bshrub_t *bshrub) {
return lfsr_shrub_isshrub(&bshrub->shrub);
}
static inline bool lfsr_bshrub_isbtree(const lfsr_bshrub_t *bshrub) {
return !lfsr_shrub_isshrub(&bshrub->shrub);
}
static inline int lfsr_bshrub_cmp(
const lfsr_bshrub_t *a,
const lfsr_bshrub_t *b) {
return lfsr_rbyd_cmp(&a->shrub, &b->shrub);
}
// needed in lfsr_bshrub_estimate
static int lfsr_mdir_lookup(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_);
// find a tight upper bound on the _full_ bshrub size, this includes
// any on-disk bshrubs, and all pending bshrubs
static lfs_ssize_t lfsr_bshrub_estimate(lfs_t *lfs,
const lfsr_bshrub_t *bshrub) {
lfs_size_t estimate = 0;
// include all unique shrubs related to our file, including the
// on-disk shrub
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &bshrub->o.mdir, LFSR_TAG_BSHRUB,
&tag, &data);
if (err < 0 && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
lfsr_shrub_t shrub;
err = lfsr_data_readshrub(lfs, &data, &bshrub->o.mdir,
&shrub);
if (err < 0) {
return err;
}
lfs_ssize_t dsize = lfsr_shrub_estimate(lfs, &shrub);
if (dsize < 0) {
return dsize;
}
estimate += dsize;
}
// this includes our current shrub
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
&& o->mdir.mid == bshrub->o.mdir.mid
&& lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)) {
lfs_ssize_t dsize = lfsr_shrub_estimate(lfs,
&((lfsr_bshrub_t*)o)->shrub);
if (dsize < 0) {
return dsize;
}
estimate += dsize;
}
}
return estimate;
}
// bshrub lookup functions
static int lfsr_bshrub_lookupleaf(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_rbyd_t *rbyd_, lfsr_srid_t *rid_,
lfsr_tag_t *tag_, lfsr_bid_t *weight_, lfsr_data_t *data_) {
return lfsr_btree_lookupleaf(lfs, &bshrub->shrub, bid,
bid_, rbyd_, rid_, tag_, weight_, data_);
}
static int lfsr_bshrub_lookupnext(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_bid_t *weight_,
lfsr_data_t *data_) {
return lfsr_btree_lookupnext(lfs, &bshrub->shrub, bid,
bid_, tag_, weight_, data_);
}
static int lfsr_bshrub_lookup(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_bid_t bid, lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
return lfsr_btree_lookup(lfs, &bshrub->shrub, bid, tag,
tag_, data_);
}
static int lfsr_bshrub_traverse(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_btraversal_t *bt,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_data_t *data_) {
return lfsr_btree_traverse(lfs, &bshrub->shrub, bt,
bid_, tag_, data_);
}
// needed in lfsr_bshrub_commitroot_
static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
const lfsr_rattr_t *rattrs, lfs_size_t rattr_count);
// commit to the bshrub root, i.e. the bshrub's shrub
static int lfsr_bshrub_commitroot_(lfs_t *lfs, lfsr_bshrub_t *bshrub,
bool split,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// we need to prevent our shrub from overflowing our mdir somehow
//
// maintaining an accurate estimate is tricky and error-prone,
// but recalculating an estimate every commit is expensive
//
// Instead, we keep track of an estimate of how many bytes have
// been progged to the shrub since the last estimate, and recalculate
// the estimate when this overflows our inline_size. This mirrors how
// block_size and rbyds interact, and amortizes the estimate cost.
// figure out how much data this commit progs
lfs_size_t commit_estimate = 0;
for (lfs_size_t i = 0; i < rattr_count; i++) {
commit_estimate += lfs->rattr_estimate
+ lfsr_rattr_dsize(rattrs[i]);
}
// does our estimate exceed our inline_size? need to recalculate an
// accurate estimate
lfs_ssize_t estimate = (split) ? (lfs_size_t)-1 : bshrub->shrub.eoff;
// this double condition avoids overflow issues
if ((lfs_size_t)estimate > lfs->cfg->inline_size
|| estimate + commit_estimate > lfs->cfg->inline_size) {
estimate = lfsr_bshrub_estimate(lfs, bshrub);
if (estimate < 0) {
return estimate;
}
// two cases where we evict:
// - overflow inline_size/2 - don't penalize for commits here
// - overflow inline_size - must include commits or risk overflow
//
// the 1/2 here prevents runaway performance with the shrub is
// near full, but it's a heuristic, so including the commit would
// just be mean
//
if ((lfs_size_t)estimate > lfs->cfg->inline_size/2
|| estimate + commit_estimate > lfs->cfg->inline_size) {
return LFS_ERR_RANGE;
}
}
// include our pending commit in the new estimate
estimate += commit_estimate;
// commit to shrub
int err = lfsr_mdir_commit(lfs, &bshrub->o.mdir, LFSR_RATTRS(
LFSR_RATTR_SHRUBCOMMIT(
(&(lfsr_shrubcommit_t){
.bshrub=bshrub,
.rid=bid,
.rattrs=rattrs,
.rattr_count=rattr_count}))));
if (err) {
return err;
}
LFS_ASSERT(bshrub->shrub.blocks[0] == bshrub->o.mdir.rbyd.blocks[0]);
// update _all_ shrubs with the new estimate
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
&& o->mdir.mid == bshrub->o.mdir.mid
&& lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)) {
((lfsr_bshrub_t*)o)->shrub.eoff = estimate;
}
}
LFS_ASSERT(bshrub->shrub.eoff == (lfs_size_t)estimate);
return 0;
}
// commit to bshrub, this is atomic
static int lfsr_bshrub_commit(lfs_t *lfs, lfsr_bshrub_t *bshrub,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// before we touch anything, we need to mark all other btree references
// as unerased
if (lfsr_bshrub_isbtree(bshrub)) {
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
&& o != &bshrub->o
&& ((lfsr_bshrub_t*)o)->shrub.blocks[0]
== bshrub->shrub.blocks[0]) {
// mark as unerased
lfsr_btree_claim(&((lfsr_bshrub_t*)o)->shrub);
}
}
}
// try to commit to the btree
lfsr_bctx_t bctx;
int err = lfsr_btree_commit_(lfs, &bshrub->shrub, &bctx,
&bid, &rattrs, &rattr_count);
if (err && err != LFS_ERR_RANGE) {
return err;
}
LFS_ASSERT(!err || rattr_count > 0);
bool split = (err == LFS_ERR_RANGE);
// when btree is shrubbed, lfsr_btree_commit_ stops at the root
// and returns with pending rattrs
if (rattr_count > 0) {
// try to commit to shrub root
err = lfsr_bshrub_commitroot_(lfs, bshrub, split,
bid, rattrs, rattr_count);
if (err && err != LFS_ERR_RANGE) {
return err;
}
// if we don't fit, convert to btree
if (err == LFS_ERR_RANGE) {
err = lfsr_btree_commitroot_(lfs, &bshrub->shrub, split,
bid, rattrs, rattr_count);
if (err) {
return err;
}
}
}
LFS_ASSERT(lfsr_shrub_trunk(&bshrub->shrub));
#ifdef LFS_DBGBTREECOMMITS
if (lfsr_bshrub_isbshrub(bshrub)) {
LFS_DEBUG("Committed bshrub "
"0x{%"PRIx32",%"PRIx32"}.%"PRIx32" w%"PRId32,
bshrub->o.mdir.rbyd.blocks[0], bshrub->o.mdir.rbyd.blocks[1],
lfsr_shrub_trunk(&bshrub->shrub),
bshrub->shrub.weight);
} else {
LFS_DEBUG("Committed btree 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"cksum %"PRIx32,
bshrub->shrub.blocks[0], lfsr_shrub_trunk(&bshrub->shrub),
bshrub->shrub.weight,
bshrub->shrub.cksum);
}
#endif
return 0;
}
/// metadata-id things ///
#define LFSR_MID(_lfs, _bid, _rid) \
(((_bid) & ~((1 << (_lfs)->mbits)-1)) + (_rid))
static inline lfsr_sbid_t lfsr_mbid(const lfs_t *lfs, lfsr_smid_t mid) {
return mid | ((1 << lfs->mbits) - 1);
}
static inline lfsr_srid_t lfsr_mrid(const lfs_t *lfs, lfsr_smid_t mid) {
// bit of a strange mapping, but we want to preserve mid=-1 => rid=-1
return (mid >> (8*sizeof(lfsr_smid_t)-1))
| (mid & ((1 << lfs->mbits) - 1));
}
// these should only be used for logging
static inline lfsr_sbid_t lfsr_dbgmbid(const lfs_t *lfs, lfsr_smid_t mid) {
if (lfs->mtree.weight == 0) {
return -1;
} else {
return mid >> lfs->mbits;
}
}
static inline lfsr_srid_t lfsr_dbgmrid(const lfs_t *lfs, lfsr_smid_t mid) {
return lfsr_mrid(lfs, mid);
}
/// metadata-pointer things ///
// the mroot anchor, mdir 0x{0,1} is the entry point into the filesystem
#define LFSR_MPTR_MROOTANCHOR() ((const lfs_block_t[2]){0, 1})
static inline int lfsr_mptr_cmp(
const lfs_block_t a[static 2],
const lfs_block_t b[static 2]) {
// note these can be in either order
if (lfs_max(a[0], a[1]) != lfs_max(b[0], b[1])) {
return lfs_max(a[0], a[1]) - lfs_max(b[0], b[1]);
} else {
return lfs_min(a[0], a[1]) - lfs_min(b[0], b[1]);
}
}
static inline bool lfsr_mptr_ismrootanchor(
const lfs_block_t mptr[static 2]) {
// mrootanchor is always at 0x{0,1}
// just check that the first block is in mroot anchor range
return mptr[0] <= 1;
}
// mptr on-disk encoding
static lfsr_data_t lfsr_data_frommptr(const lfs_block_t mptr[static 2],
uint8_t buffer[static LFSR_MPTR_DSIZE]) {
// blocks should not exceed 31-bits
LFS_ASSERT(mptr[0] <= 0x7fffffff);
LFS_ASSERT(mptr[1] <= 0x7fffffff);
lfs_ssize_t d = 0;
for (int i = 0; i < 2; i++) {
lfs_ssize_t d_ = lfs_toleb128(mptr[i], &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
}
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readmptr(lfs_t *lfs, lfsr_data_t *data,
lfs_block_t mptr[static 2]) {
for (int i = 0; i < 2; i++) {
int err = lfsr_data_readleb128(lfs, data, &mptr[i]);
if (err) {
return err;
}
}
return 0;
}
/// various flag things ///
// open flags
static inline bool lfsr_o_isrdonly(uint32_t flags) {
return (flags & LFS_O_MODE) == LFS_O_RDONLY;
}
static inline bool lfsr_o_iswronly(uint32_t flags) {
return (flags & LFS_O_MODE) == LFS_O_WRONLY;
}
static inline bool lfsr_o_iscreat(uint32_t flags) {
return flags & LFS_O_CREAT;
}
static inline bool lfsr_o_isexcl(uint32_t flags) {
return flags & LFS_O_EXCL;
}
static inline bool lfsr_o_istrunc(uint32_t flags) {
return flags & LFS_O_TRUNC;
}
static inline bool lfsr_o_isappend(uint32_t flags) {
return flags & LFS_O_APPEND;
}
static inline bool lfsr_o_isflush(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_FLUSH
return true;
#else
return flags & LFS_O_FLUSH;
#endif
}
static inline bool lfsr_o_issync(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_SYNC
return true;
#else
return flags & LFS_O_SYNC;
#endif
}
static inline bool lfsr_o_isdesync(uint32_t flags) {
return flags & LFS_O_DESYNC;
}
// internal open flags
static inline uint8_t lfsr_o_type(uint32_t flags) {
return flags >> 28;
}
static inline uint32_t lfsr_o_typeflags(uint8_t type) {
return (uint32_t)type << 28;
}
static inline void lfsr_o_settype(uint32_t *flags, uint8_t type) {
*flags = (*flags & ~LFS_o_TYPE) | lfsr_o_typeflags(type);
}
static inline bool lfsr_o_isbshrub(uint32_t flags) {
return lfsr_o_type(flags) == LFS_TYPE_REG
|| lfsr_o_type(flags) == LFS_type_TRAVERSAL;
}
static inline bool lfsr_o_iszombie(uint32_t flags) {
return flags & LFS_o_ZOMBIE;
}
static inline bool lfsr_o_isuncreat(uint32_t flags) {
return flags & LFS_o_UNCREAT;
}
static inline bool lfsr_o_isunsync(uint32_t flags) {
return flags & LFS_o_UNSYNC;
}
static inline bool lfsr_o_isuncryst(uint32_t flags) {
return flags & LFS_o_UNCRYST;
}
static inline bool lfsr_o_isungraft(uint32_t flags) {
return flags & LFS_o_UNGRAFT;
}
static inline bool lfsr_o_isunflush(uint32_t flags) {
return flags & LFS_o_UNFLUSH;
}
// custom attr flags
static inline bool lfsr_a_islazy(uint32_t flags) {
return flags & LFS_A_LAZY;
}
// traversal flags
static inline bool lfsr_t_isrdonly(uint32_t flags) {
return flags & LFS_T_RDONLY;
}
static inline bool lfsr_t_ismtreeonly(uint32_t flags) {
return flags & LFS_T_MTREEONLY;
}
static inline bool lfsr_t_ismkconsistent(uint32_t flags) {
return flags & LFS_T_MKCONSISTENT;
}
static inline bool lfsr_t_islookahead(uint32_t flags) {
return flags & LFS_T_LOOKAHEAD;
}
static inline bool lfsr_t_iscompact(uint32_t flags) {
return flags & LFS_T_COMPACT;
}
static inline bool lfsr_t_isckmeta(uint32_t flags) {
return flags & LFS_T_CKMETA;
}
static inline bool lfsr_t_isckdata(uint32_t flags) {
return flags & LFS_T_CKDATA;
}
// internal traversal flags
static inline uint8_t lfsr_t_tstate(uint32_t flags) {
return (flags >> 16) & 0xf;
}
static inline uint32_t lfsr_t_tstateflags(uint8_t tstate) {
return (uint32_t)tstate << 16;
}
static inline void lfsr_t_settstate(uint32_t *flags, uint8_t tstate) {
*flags = (*flags & ~LFS_t_TSTATE) | lfsr_t_tstateflags(tstate);
}
static inline uint8_t lfsr_t_btype(uint32_t flags) {
return (flags >> 20) & 0x0f;
}
static inline uint32_t lfsr_t_btypeflags(uint8_t btype) {
return (uint32_t)btype << 20;
}
static inline void lfsr_t_setbtype(uint32_t *flags, uint8_t btype) {
*flags = (*flags & ~LFS_t_BTYPE) | lfsr_t_btypeflags(btype);
}
static inline bool lfsr_t_isdirty(uint32_t flags) {
return flags & LFS_t_DIRTY;
}
static inline bool lfsr_t_ismutated(uint32_t flags) {
return flags & LFS_t_MUTATED;
}
static inline uint32_t lfsr_t_swapdirty(uint32_t flags) {
uint32_t x = ((flags >> 24) ^ (flags >> 25)) & 0x1;
return flags ^ (x << 24) ^ (x << 25);
}
// mount flags
static inline bool lfsr_m_isrdonly(uint32_t flags) {
return flags & LFS_M_RDONLY;
}
#ifdef LFS_REVDBG
static inline bool lfsr_m_isrevdbg(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_REVDBG
return true;
#else
return flags & LFS_M_REVDBG;
#endif
}
#endif
#ifdef LFS_REVNOISE
static inline bool lfsr_m_isrevnoise(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_REVNOISE
return true;
#else
return flags & LFS_M_REVNOISE;
#endif
}
#endif
#ifdef LFS_CKPROGS
static inline bool lfsr_m_isckprogs(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_CKPROGS
return true;
#else
return flags & LFS_M_CKPROGS;
#endif
}
#endif
#ifdef LFS_CKFETCHES
static inline bool lfsr_m_isckfetches(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_CKFETCHES
return true;
#else
return flags & LFS_M_CKFETCHES;
#endif
}
#endif
#ifdef LFS_CKMETAPARITY
static inline bool lfsr_m_isckparity(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_CKMETAPARITY
return true;
#else
return flags & LFS_M_CKMETAPARITY;
#endif
}
#endif
#ifdef LFS_CKDATACKSUMREADS
static inline bool lfsr_m_isckdatacksums(uint32_t flags) {
(void)flags;
#ifdef LFS_YES_CKDATACKSUMREADS
return true;
#else
return flags & LFS_M_CKDATACKSUMREADS;
#endif
}
#endif
// other internal flags
#ifdef LFS_REVDBG
static inline bool lfsr_i_isinmtree(uint32_t flags) {
return flags & LFS_i_INMTREE;
}
#endif
/// opened mdir things ///
// we maintain a linked-list of all opened mdirs, in order to keep
// metadata state in-sync, these may be casted to specific file types
static bool lfsr_omdir_isopen(const lfs_t *lfs, const lfsr_omdir_t *o) {
for (lfsr_omdir_t *o_ = lfs->omdirs; o_; o_ = o_->next) {
if (o_ == o) {
return true;
}
}
return false;
}
static void lfsr_omdir_open(lfs_t *lfs, lfsr_omdir_t *o) {
LFS_ASSERT(!lfsr_omdir_isopen(lfs, o));
// add to opened list
o->next = lfs->omdirs;
lfs->omdirs = o;
}
// needed in lfsr_omdir_close
static void lfsr_omdir_clobber(lfs_t *lfs, const lfsr_omdir_t *o,
uint32_t flags);
static void lfsr_omdir_close(lfs_t *lfs, lfsr_omdir_t *o) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, o));
// make sure we're not entangled in any traversals, note we don't
// set the dirty bit here
lfsr_omdir_clobber(lfs, o, 0);
// remove from opened list
for (lfsr_omdir_t **o_ = &lfs->omdirs; *o_; o_ = &(*o_)->next) {
if (*o_ == o) {
*o_ = (*o_)->next;
break;
}
}
}
// check if a given mid is open
static bool lfsr_omdir_ismidopen(const lfs_t *lfs,
lfsr_smid_t mid, uint32_t mask) {
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// we really only care about regular open files here, all
// others are either transient (dirs) or fake (orphans)
if (lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == mid
// allow caller to ignore files with specific flags
&& !(o->flags & ~mask)) {
return true;
}
}
return false;
}
// traversal invalidation things
// needed in lfsr_omdir_clobber
static void lfsr_traversal_clobber(lfs_t *lfs, lfsr_traversal_t *t);
// clobber any traversals referencing our mdir
static void lfsr_omdir_clobber(lfs_t *lfs, const lfsr_omdir_t *o,
uint32_t flags) {
for (lfsr_omdir_t *o_ = lfs->omdirs; o_; o_ = o_->next) {
if (lfsr_o_type(o_->flags) == LFS_type_TRAVERSAL) {
o_->flags |= flags;
if (o && ((lfsr_traversal_t*)o_)->ot == o) {
lfsr_traversal_clobber(lfs, (lfsr_traversal_t*)o_);
}
}
}
}
// clobber all traversals
static void lfsr_fs_clobber(lfs_t *lfs, uint32_t flags) {
lfsr_omdir_clobber(lfs, NULL, flags);
}
/// Global-state things ///
// grm (global remove) things
static inline lfs_size_t lfsr_grm_count(const lfs_t *lfs) {
return (lfs->grm.queue[0] != 0) + (lfs->grm.queue[1] != 0);
}
static inline void lfsr_grm_push(lfs_t *lfs, lfsr_smid_t mid) {
// note mid=0.0 always maps to the root bookmark and should never
// be grmed
LFS_ASSERT(mid != 0);
LFS_ASSERT(lfs->grm.queue[1] == 0);
lfs->grm.queue[1] = lfs->grm.queue[0];
lfs->grm.queue[0] = mid;
}
static inline lfsr_smid_t lfsr_grm_pop(lfs_t *lfs) {
lfsr_smid_t mid = lfs->grm.queue[0];
lfs->grm.queue[0] = lfs->grm.queue[1];
lfs->grm.queue[1] = 0;
return mid;
}
static inline bool lfsr_grm_ismidrm(const lfs_t *lfs, lfsr_smid_t mid) {
return mid != 0
&& (lfs->grm.queue[0] == mid
|| lfs->grm.queue[1] == mid);
}
#define LFSR_DATA_GRM(_grm, _buffer) \
((struct {lfsr_data_t d;}){lfsr_data_fromgrm(_grm, _buffer)}.d)
static lfsr_data_t lfsr_data_fromgrm(const lfs_t *lfs,
uint8_t buffer[static LFSR_GRM_DSIZE]) {
// make sure to zero so we don't leak any info
lfs_memset(buffer, 0, LFSR_GRM_DSIZE);
// encode grms
lfs_size_t count = lfsr_grm_count(lfs);
lfs_ssize_t d = 0;
for (lfs_size_t i = 0; i < count; i++) {
lfs_ssize_t d_ = lfs_toleb128(lfs->grm.queue[i], &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
}
return LFSR_DATA_BUF(buffer, lfs_memlen(buffer, LFSR_GRM_DSIZE));
}
// required by lfsr_data_readgrm
static inline lfsr_mid_t lfsr_mtree_weight(lfs_t *lfs);
static int lfsr_data_readgrm(lfs_t *lfs, lfsr_data_t *data) {
// clear first
lfs->grm.queue[0] = 0;
lfs->grm.queue[1] = 0;
// decode grms, these are terminated by either a null (mid=0) or the
// size of the grm buffer
for (lfs_size_t i = 0; i < 2; i++) {
lfsr_mid_t mid;
int err = lfsr_data_readleb128(lfs, data, &mid);
if (err) {
return err;
}
// null grm?
if (!mid) {
break;
}
// grm inside mtree?
LFS_ASSERT(mid < lfsr_mtree_weight(lfs));
lfs->grm.queue[i] = mid;
}
return 0;
}
// some mdir-related gstate things we need
// zero any pending gdeltas
static void lfsr_fs_flushgdelta(lfs_t *lfs) {
// zero the gcksumdelta
lfs->gcksum_d = 0;
// zero the grmdelta
lfs_memset(lfs->grm_d, 0, LFSR_GRM_DSIZE);
}
// commit any pending gdeltas
static void lfsr_fs_commitgdelta(lfs_t *lfs) {
// keep track of the on-disk gcksum
lfs->gcksum_p = lfs->gcksum;
// keep track of the on-disk grm
lfsr_data_fromgrm(lfs, lfs->grm_p);
}
// revert gstate to on-disk state
static void lfsr_fs_revertgdelta(lfs_t *lfs) {
// revert to the on-disk gcksum
lfs->gcksum = lfs->gcksum_p;
// revert to the on-disk grm
int err = lfsr_data_readgrm(lfs,
&LFSR_DATA_BUF(lfs->grm_p, LFSR_GRM_DSIZE));
if (err) {
LFS_UNREACHABLE();
}
}
// append and consume any pending gstate
static int lfsr_rbyd_appendgdelta(lfs_t *lfs, lfsr_rbyd_t *rbyd) {
// note gcksums are a special case and handled directly in
// lfsr_mdir_commit__/lfsr_rbyd_appendcksum_
// pending grm state?
uint8_t grmdelta_[LFSR_GRM_DSIZE];
lfsr_data_fromgrm(lfs, grmdelta_);
lfs_memxor(grmdelta_, lfs->grm_p, LFSR_GRM_DSIZE);
lfs_memxor(grmdelta_, lfs->grm_d, LFSR_GRM_DSIZE);
if (lfs_memlen(grmdelta_, LFSR_GRM_DSIZE) != 0) {
// make sure to xor any existing delta
lfsr_data_t data;
int err = lfsr_rbyd_lookup(lfs, rbyd, -1, LFSR_TAG_GRMDELTA,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
uint8_t grmdelta[LFSR_GRM_DSIZE];
lfs_memset(grmdelta, 0, LFSR_GRM_DSIZE);
if (err != LFS_ERR_NOENT) {
lfs_ssize_t d = lfsr_data_read(lfs, &data,
grmdelta, LFSR_GRM_DSIZE);
if (d < 0) {
return d;
}
}
lfs_memxor(grmdelta_, grmdelta, LFSR_GRM_DSIZE);
// append to our rbyd, replacing any existing delta
lfs_size_t size = lfs_memlen(grmdelta_, LFSR_GRM_DSIZE);
err = lfsr_rbyd_appendrattr(lfs, rbyd, -1, LFSR_RATTR_BUF(
// opportunistically remove this tag if delta is all zero
(size == 0)
? LFSR_TAG_RM | LFSR_TAG_GRMDELTA
: LFSR_TAG_GRMDELTA, 0,
grmdelta_, size));
if (err) {
return err;
}
}
return 0;
}
static int lfsr_fs_consumegdelta(lfs_t *lfs, const lfsr_mdir_t *mdir) {
// consume any gcksum deltas
lfs->gcksum_d ^= mdir->gcksumdelta;
// consume any grm deltas
lfsr_data_t data;
int err = lfsr_rbyd_lookup(lfs, &mdir->rbyd, -1, LFSR_TAG_GRMDELTA,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
uint8_t grmdelta[LFSR_GRM_DSIZE];
lfs_ssize_t d = lfsr_data_read(lfs, &data, grmdelta, LFSR_GRM_DSIZE);
if (d < 0) {
return d;
}
lfs_memxor(lfs->grm_d, grmdelta, d);
}
return 0;
}
/// Revision count things ///
// in mdirs, our revision count is broken down into three parts:
//
// vvvvrrrr rrrrrrnn nnnnnnnn nnnnnnnn
// '-.''----.----''---------.--------'
// '------|---------------|---------- 4-bit relocation revision
// '---------------|---------- recycle-bits recycle counter
// '---------- pseudorandom noise (if revnoise)
//
// in revdbg mode, the bottom 24 bits are initialized with a hint based
// on rbyd type, though it may be overwritten by the recycle counter if
// it overlaps:
//
// vvvv---- --1----1 -11-1--1 -11-1--- (68 69 21 v0 hi!.) mroot anchor
// vvvv---- -111111- -111--1- -11-11-1 (6d 72 7e v0 mr~.) mroot
// vvvv---- -111111- -11--1-- -11-11-1 (6d 64 7e v0 md~.) mdir
// vvvv---- -111111- -111-1-- -11---1- (62 74 7e v0 bt~.) file btree node
// vvvv---- -111111- -11-11-1 -11---1- (62 6d 7e v0 bm~.) mtree node
//
// needed in lfsr_rev_init
static inline bool lfsr_mdir_ismrootanchor(const lfsr_mdir_t *mdir);
static inline int lfsr_mdir_cmp(const lfsr_mdir_t *a, const lfsr_mdir_t *b);
static inline uint32_t lfsr_rev_init(lfs_t *lfs, const lfsr_mdir_t *mdir,
uint32_t rev) {
(void)lfs;
(void)mdir;
// we really only care about the top revision bits here
rev &= ~((1 << 28)-1);
// increment revision
rev += 1 << 28;
#ifdef LFS_REVDBG
// include debug bits?
if (lfsr_m_isrevdbg(lfs->flags)) {
// mroot?
if (mdir->mid == -1 || lfsr_mdir_cmp(mdir, &lfs->mroot) == 0) {
rev |= 0x007e726d;
// mdir?
} else {
rev |= 0x007e646d;
}
}
#endif
#ifdef LFS_REVNOISE
// xor in pseudorandom noise
if (lfsr_m_isrevnoise(lfs->flags)) {
rev ^= ((1 << (28-lfs_smax(lfs->recycle_bits, 0)))-1) & lfs->gcksum;
}
#endif
return rev;
}
// btrees don't normally need revision counts, but we make use of them
// if revdbg or revnoise is enabled
static inline uint32_t lfsr_rev_btree(lfs_t *lfs) {
(void)lfs;
uint32_t rev = 0;
#ifdef LFS_REVDBG
// include debug bits?
if (lfsr_m_isrevdbg(lfs->flags)) {
// mtree?
if (lfsr_i_isinmtree(lfs->flags)) {
rev |= 0x007e6d62;
// file btree?
} else {
rev |= 0x007e7462;
}
}
#endif
#ifdef LFS_REVNOISE
// xor in pseudorandom noise
if (lfsr_m_isrevnoise(lfs->flags)) {
// keep the top nibble zero
rev ^= 0x0fffffff & lfs->gcksum;
}
#endif
return rev;
}
static inline bool lfsr_rev_needsrelocation(lfs_t *lfs, uint32_t rev) {
if (lfs->recycle_bits == -1) {
return false;
}
// does out recycle counter overflow?
uint32_t rev_ = rev + (1 << (28-lfs_smax(lfs->recycle_bits, 0)));
return (rev_ >> 28) != (rev >> 28);
}
static inline uint32_t lfsr_rev_inc(lfs_t *lfs, uint32_t rev) {
// increment recycle counter/revision
rev += 1 << (28-lfs_smax(lfs->recycle_bits, 0));
#ifdef LFS_REVNOISE
// xor in pseudorandom noise
if (lfsr_m_isrevnoise(lfs->flags)) {
rev ^= ((1 << (28-lfs_smax(lfs->recycle_bits, 0)))-1) & lfs->gcksum;
}
#endif
return rev;
}
/// Metadata pair stuff ///
// mdir convenience functions
static inline void lfsr_mdir_claim(lfsr_mdir_t *mdir) {
lfsr_rbyd_claim(&mdir->rbyd);
}
static inline int lfsr_mdir_cmp(const lfsr_mdir_t *a, const lfsr_mdir_t *b) {
return lfsr_mptr_cmp(a->rbyd.blocks, b->rbyd.blocks);
}
static inline bool lfsr_mdir_ismrootanchor(const lfsr_mdir_t *mdir) {
return lfsr_mptr_ismrootanchor(mdir->rbyd.blocks);
}
static inline void lfsr_mdir_sync(lfsr_mdir_t *a, const lfsr_mdir_t *b) {
// copy over everything but the mid
a->rbyd = b->rbyd;
a->gcksumdelta = b->gcksumdelta;
}
// mdir operations
static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_smid_t mid, const lfs_block_t mptr[static 2]) {
// create a copy of the mptr, both so we can swap the blocks to keep
// track of the current revision, and to prevents issues if mptr
// references the blocks in the mdir
lfs_block_t blocks[2] = {mptr[0], mptr[1]};
// read both revision counts, try to figure out which block
// has the most recent revision
uint32_t revs[2] = {0, 0};
for (int i = 0; i < 2; i++) {
int err = lfsr_bd_read(lfs, blocks[0], 0, 0,
&revs[0], sizeof(uint32_t));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
revs[i] = lfs_fromle32(&revs[i]);
if (i == 0
|| err == LFS_ERR_CORRUPT
|| lfs_scmp(revs[1], revs[0]) > 0) {
LFS_SWAP(lfs_block_t, &blocks[0], &blocks[1]);
LFS_SWAP(uint32_t, &revs[0], &revs[1]);
}
}
// try to fetch rbyds in the order of most recent to least recent
for (int i = 0; i < 2; i++) {
int err = lfsr_rbyd_fetch_(lfs,
&mdir->rbyd, &mdir->gcksumdelta,
blocks[0], 0);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err != LFS_ERR_CORRUPT) {
mdir->mid = mid;
// keep track of other block for compactions
mdir->rbyd.blocks[1] = blocks[1];
#ifdef LFS_DBGMDIRFETCHES
LFS_DEBUG("Fetched mdir %"PRId32" "
"0x{%"PRIx32",%"PRIx32"}.%"PRIx32" w%"PRId32", "
"cksum %"PRIx32,
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1],
lfsr_rbyd_trunk(&mdir->rbyd),
mdir->rbyd.weight,
mdir->rbyd.cksum);
#endif
return 0;
}
LFS_SWAP(lfs_block_t, &blocks[0], &blocks[1]);
LFS_SWAP(uint32_t, &revs[0], &revs[1]);
}
// could not find a non-corrupt rbyd
return LFS_ERR_CORRUPT;
}
static int lfsr_data_fetchmdir(lfs_t *lfs,
lfsr_data_t *data, lfsr_smid_t mid,
lfsr_mdir_t *mdir) {
// decode mptr and fetch
int err = lfsr_data_readmptr(lfs, data,
mdir->rbyd.blocks);
if (err) {
return err;
}
return lfsr_mdir_fetch(lfs, mdir, mid, mdir->rbyd.blocks);
}
static lfsr_tag_t lfsr_mdir_nametag(const lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_smid_t mid, lfsr_tag_t tag) {
(void)mdir;
// intercept pending grms here and pretend they're orphaned
// stickynotes
//
// fortunately pending grms/orphaned stickynotes have roughly the
// same semantics, and this makes it easier to manage the implied
// mid gap in higher-levels
if (lfsr_grm_ismidrm(lfs, mid)) {
return LFSR_TAG_ORPHAN;
// if we find a stickynote, check to see if there are any open
// in-sync file handles to decide if it really exists
} else if (tag == LFSR_TAG_STICKYNOTE
&& !lfsr_omdir_ismidopen(lfs, mid,
~LFS_o_ZOMBIE & ~LFS_O_DESYNC)) {
return LFSR_TAG_ORPHAN;
// map unknown types -> LFSR_TAG_UNKNOWN, this simplifies higher
// levels and prevents collisions with internal types
//
// Note future types should probably come with WCOMPAT flags, and be
// at least reported on non-supporting filesystems
} else if (tag < LFSR_TAG_REG || tag > LFSR_TAG_BOOKMARK) {
return LFSR_TAG_UNKNOWN;
}
return tag;
}
static int lfsr_mdir_lookupnext(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
lfsr_srid_t rid__;
lfsr_tag_t tag__;
int err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
lfsr_mrid(lfs, mdir->mid), tag,
&rid__, &tag__, NULL, data_);
if (err) {
return err;
}
// this is very similar to lfsr_rbyd_lookupnext, but we error if
// lookupnext would change mids
if (rid__ != lfsr_mrid(lfs, mdir->mid)) {
return LFS_ERR_NOENT;
}
// map name tags to understood types
if (lfsr_tag_suptype(tag__) == LFSR_TAG_NAME) {
tag__ = lfsr_mdir_nametag(lfs, mdir, mdir->mid, tag__);
}
if (tag_) {
*tag_ = tag__;
}
return 0;
}
static int lfsr_mdir_lookup(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
lfsr_tag_t tag__;
int err = lfsr_mdir_lookupnext(lfs, mdir, lfsr_tag_key(tag),
&tag__, data_);
if (err) {
return err;
}
// lookup finds the next-smallest tag, all we need to do is fail if it
// picks up the wrong tag
if ((tag__ & lfsr_tag_mask(tag)) != (tag & lfsr_tag_mask(tag))) {
return LFS_ERR_NOENT;
}
if (tag_) {
*tag_ = tag__;
}
return 0;
}
/// Metadata-tree things ///
static inline lfsr_mid_t lfsr_mtree_weight(lfs_t *lfs) {
return lfs_max(
lfs->mtree.weight,
1 << lfs->mbits);
}
// lookup mdir containing a given mid
static int lfsr_mtree_lookup(lfs_t *lfs, lfsr_smid_t mid,
lfsr_mdir_t *mdir_) {
// looking up mid=-1 is probably a mistake
LFS_ASSERT(mid >= 0);
// out of bounds?
if ((lfsr_mid_t)mid >= lfsr_mtree_weight(lfs)) {
return LFS_ERR_NOENT;
}
// looking up mroot?
if (lfs->mtree.weight == 0) {
// treat inlined mdir as mid=0
mdir_->mid = mid;
lfsr_mdir_sync(mdir_, &lfs->mroot);
return 0;
// look up mdir in actual mtree
} else {
lfsr_bid_t bid;
lfsr_srid_t rid;
lfsr_tag_t tag;
lfsr_bid_t weight;
lfsr_data_t data;
int err = lfsr_btree_lookupleaf(lfs, &lfs->mtree, mid,
&bid, &mdir_->rbyd, &rid, &tag, &weight, &data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
LFS_ASSERT((lfsr_sbid_t)bid == lfsr_mbid(lfs, mid));
LFS_ASSERT(weight == (lfsr_bid_t)(1 << lfs->mbits));
LFS_ASSERT(tag == LFSR_TAG_MNAME
|| tag == LFSR_TAG_MDIR);
// if we found an mname, lookup the mdir
if (tag == LFSR_TAG_MNAME) {
err = lfsr_rbyd_lookup(lfs, &mdir_->rbyd, rid, LFSR_TAG_MDIR,
NULL, &data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// fetch mdir
return lfsr_data_fetchmdir(lfs, &data, mid,
mdir_);
}
}
// this is the same as lfsr_btree_commit, but we set the inmtree flag
// for debugging reasons
static int lfsr_mtree_commit(lfs_t *lfs, lfsr_btree_t *mtree,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
#ifdef LFS_REVDBG
lfs->flags |= LFS_i_INMTREE;
#endif
int err = lfsr_btree_commit(lfs, mtree, bid, rattrs, rattr_count);
#ifdef LFS_REVDBG
lfs->flags &= ~LFS_i_INMTREE;
#endif
return err;
}
/// Mdir commit logic ///
// this is the gooey atomic center of littlefs
//
// any mutation must go through lfsr_mdir_commit to persist on disk
//
// this makes lfsr_mdir_commit also responsible for propagating changes
// up through the mtree/mroot chain, and through any internal structures,
// making lfsr_mdir_commit quite involved and a bit of a mess.
// low-level mdir operations needed by lfsr_mdir_commit
static int lfsr_mdir_alloc__(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_smid_t mid, bool partial) {
// assign the mid
mdir->mid = mid;
// default to zero gcksumdelta
mdir->gcksumdelta = 0;
if (!partial) {
// allocate one block without an erase
lfs_sblock_t block = lfs_alloc(lfs, false);
if (block < 0) {
return block;
}
mdir->rbyd.blocks[1] = block;
}
// read the new revision count
//
// we use whatever is on-disk to avoid needing to rewrite the
// redund block
uint32_t rev;
int err = lfsr_bd_read(lfs, mdir->rbyd.blocks[1], 0, 0,
&rev, sizeof(uint32_t));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// note we allow corrupt errors here, as long as they are consistent
rev = (err != LFS_ERR_CORRUPT) ? lfs_fromle32(&rev) : 0;
// reset recycle bits in revision count and increment
rev = lfsr_rev_init(lfs, mdir, rev);
relocate:;
// allocate another block with an erase
lfs_sblock_t block = lfs_alloc(lfs, true);
if (block < 0) {
return block;
}
mdir->rbyd.blocks[0] = block;
mdir->rbyd.weight = 0;
mdir->rbyd.trunk = 0;
mdir->rbyd.eoff = 0;
mdir->rbyd.cksum = 0;
// write our revision count
err = lfsr_rbyd_appendrev(lfs, &mdir->rbyd, rev);
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
return 0;
}
static int lfsr_mdir_swap__(lfs_t *lfs, lfsr_mdir_t *mdir_,
const lfsr_mdir_t *mdir, bool force) {
// assign the mid
mdir_->mid = mdir->mid;
// reset to zero gcksumdelta, upper layers should handle this
mdir_->gcksumdelta = 0;
// first thing we need to do is read our current revision count
uint32_t rev;
int err = lfsr_bd_read(lfs, mdir->rbyd.blocks[0], 0, 0,
&rev, sizeof(uint32_t));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// note we allow corrupt errors here, as long as they are consistent
rev = (err != LFS_ERR_CORRUPT) ? lfs_fromle32(&rev) : 0;
// increment our revision count
rev = lfsr_rev_inc(lfs, rev);
// decide if we need to relocate
if (!force && lfsr_rev_needsrelocation(lfs, rev)) {
return LFS_ERR_NOSPC;
}
// swap our blocks
mdir_->rbyd.blocks[0] = mdir->rbyd.blocks[1];
mdir_->rbyd.blocks[1] = mdir->rbyd.blocks[0];
mdir_->rbyd.weight = 0;
mdir_->rbyd.trunk = 0;
mdir_->rbyd.eoff = 0;
mdir_->rbyd.cksum = 0;
// erase, preparing for compact
err = lfsr_bd_erase(lfs, mdir_->rbyd.blocks[0]);
if (err) {
return err;
}
// increment our revision count and write it to our rbyd
err = lfsr_rbyd_appendrev(lfs, &mdir_->rbyd, rev);
if (err) {
return err;
}
return 0;
}
// low-level mdir commit, does not handle mtree/mlist/compaction/etc
static int lfsr_mdir_commit__(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_srid_t start_rid, lfsr_srid_t end_rid,
lfsr_smid_t mid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// since we only ever commit to one mid or split, we can ignore the
// entire rattr-list if our mid is out of range
lfsr_srid_t rid = lfsr_mrid(lfs, mid);
if (rid >= start_rid
// note the use of rid+1 and unsigned comparison here to
// treat end_rid=-1 as "unbounded" in such a way that rid=-1
// is still included
&& (lfs_size_t)(rid + 1) <= (lfs_size_t)end_rid) {
for (lfs_size_t i = 0; i < rattr_count; i++) {
// we just happen to never split in an mdir commit
LFS_ASSERT(!(i > 0 && lfsr_rattr_isinsert(rattrs[i])));
// rattr lists can be chained, but only tail-recursively
if (rattrs[i].tag == LFSR_TAG_RATTRS) {
// must be the last tag
LFS_ASSERT(i == rattr_count-1);
const lfsr_rattr_t *rattrs_ = rattrs[i].u.etc;
lfs_size_t rattr_count_ = rattrs[i].count;
// switch to chained rattr-list
rattrs = rattrs_;
rattr_count = rattr_count_;
i = -1;
continue;
// shrub tags append a set of attributes to an unrelated trunk
// in our rbyd
} else if (rattrs[i].tag == LFSR_TAG_SHRUBCOMMIT) {
const lfsr_shrubcommit_t *shrubcommit = rattrs[i].u.etc;
lfsr_bshrub_t *bshrub_ = shrubcommit->bshrub;
lfsr_srid_t rid_ = shrubcommit->rid;
const lfsr_rattr_t *rattrs_ = shrubcommit->rattrs;
lfs_size_t rattr_count_ = shrubcommit->rattr_count;
// reset shrub if it doesn't live in our block, this happens
// when converting from a btree
if (!lfsr_bshrub_isbshrub(bshrub_)) {
bshrub_->shrub_.blocks[0] = mdir->rbyd.blocks[0];
bshrub_->shrub_.trunk = LFSR_RBYD_ISSHRUB | 0;
bshrub_->shrub_.weight = 0;
}
// commit to shrub
int err = lfsr_shrub_commit(lfs,
&mdir->rbyd, &bshrub_->shrub_,
rid_, rattrs_, rattr_count_);
if (err) {
return err;
}
// push a new grm, this tag lets us push grms atomically when
// creating new mids
} else if (rattrs[i].tag == LFSR_TAG_GRMPUSH) {
// do nothing here, this is handled up in lfsr_mdir_commit
// move tags copy over any tags associated with the source's rid
// TODO can this be deduplicated with lfsr_mdir_compact__ more?
// it _really_ wants to be deduplicated
} else if (rattrs[i].tag == LFSR_TAG_MOVE) {
const lfsr_mdir_t *mdir__ = rattrs[i].u.etc;
// skip the name tag, this is always replaced by upper layers
lfsr_tag_t tag = LFSR_TAG_STRUCT-1;
while (true) {
lfsr_data_t data;
int err = lfsr_mdir_lookupnext(lfs, mdir__, tag+1,
&tag, &data);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// found an inlined shrub? we need to compact the shrub
// as well to bring it along with us
if (tag == LFSR_TAG_BSHRUB) {
lfsr_shrub_t shrub;
err = lfsr_data_readshrub(lfs, &data, mdir__,
&shrub);
if (err) {
return err;
}
// compact our shrub
err = lfsr_shrub_compact(lfs, &mdir->rbyd, &shrub,
&shrub);
if (err) {
return err;
}
// write our new shrub tag
err = lfsr_rbyd_appendrattr(lfs, &mdir->rbyd,
rid - lfs_smax(start_rid, 0),
LFSR_RATTR_SHRUB(LFSR_TAG_BSHRUB, 0, &shrub));
if (err) {
return err;
}
// append the rattr
} else {
err = lfsr_rbyd_appendrattr(lfs, &mdir->rbyd,
rid - lfs_smax(start_rid, 0),
LFSR_RATTR_DATA(tag, 0, &data));
if (err) {
return err;
}
}
}
// we're not quite done! we also need to bring over any
// unsynced files
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
// belongs to our mid?
&& o->mdir.mid == mdir__->mid
// is a bshrub?
&& lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)
// only compact once, first compact should
// stage the new block
&& ((lfsr_bshrub_t*)o)->shrub_.blocks[0]
!= mdir->rbyd.blocks[0]) {
int err = lfsr_shrub_compact(lfs, &mdir->rbyd,
&((lfsr_bshrub_t*)o)->shrub_,
&((lfsr_bshrub_t*)o)->shrub);
if (err) {
return err;
}
}
}
// custom attributes need to be reencoded into our tag format
} else if (rattrs[i].tag == LFSR_TAG_ATTRS) {
const struct lfs_attr *attrs_ = rattrs[i].u.etc;
lfs_size_t attr_count_ = rattrs[i].count;
for (lfs_size_t j = 0; j < attr_count_; j++) {
// skip readonly attrs and lazy attrs
if (lfsr_o_isrdonly(attrs_[j].flags)) {
continue;
}
// first lets check if the attr changed, we don't want
// to append attrs unless we have to
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, mdir,
LFSR_TAG_ATTR(attrs_[j].type),
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// does disk match our attr?
lfs_scmp_t cmp = lfsr_attr_cmp(lfs, &attrs_[j],
(err != LFS_ERR_NOENT) ? &data : NULL);
if (cmp < 0) {
return cmp;
}
if (cmp == LFS_CMP_EQ) {
continue;
}
// append the custom attr
err = lfsr_rbyd_appendrattr(lfs, &mdir->rbyd,
rid - lfs_smax(start_rid, 0),
// removing or updating?
(lfsr_attr_isnoattr(&attrs_[j]))
? LFSR_RATTR(
LFSR_TAG_RM
| LFSR_TAG_ATTR(attrs_[j].type), 0)
: LFSR_RATTR_BUF(
LFSR_TAG_ATTR(attrs_[j].type), 0,
attrs_[j].buffer,
lfsr_attr_size(&attrs_[j])));
if (err) {
return err;
}
}
// write out normal tags normally
} else {
LFS_ASSERT(!lfsr_tag_isinternal(rattrs[i].tag));
int err = lfsr_rbyd_appendrattr(lfs, &mdir->rbyd,
rid - lfs_smax(start_rid, 0),
rattrs[i]);
if (err) {
return err;
}
}
// adjust rid
rid = lfsr_rattr_nextrid(rattrs[i], rid);
}
}
// abort the commit if our weight dropped to zero!
//
// If we finish the commit it becomes immediately visible, but we really
// need to atomically remove this mdir from the mtree. Leave the actual
// remove up to upper layers.
if (mdir->rbyd.weight == 0
// unless we are an mroot
&& !(mdir->mid == -1 || lfsr_mdir_cmp(mdir, &lfs->mroot) == 0)) {
// note! we can no longer read from this mdir as our pcache may
// be clobbered
return LFS_ERR_NOENT;
}
// append any gstate?
if (start_rid <= -2) {
int err = lfsr_rbyd_appendgdelta(lfs, &mdir->rbyd);
if (err) {
return err;
}
}
// save our canonical cksum
//
// note this is before we calculate gcksumdelta, otherwise
// everything would get all self-referential
uint32_t cksum = mdir->rbyd.cksum;
// append gkcsumdelta?
if (start_rid <= -2) {
// figure out changes to our gcksumdelta
mdir->gcksumdelta ^= lfs_crc32c_cube(lfs->gcksum_p)
^ lfs_crc32c_cube(lfs->gcksum ^ cksum)
^ lfs->gcksum_d;
int err = lfsr_rbyd_appendrattr_(lfs, &mdir->rbyd, LFSR_RATTR_LE32(
LFSR_TAG_GCKSUMDELTA, 0, mdir->gcksumdelta));
if (err) {
return err;
}
}
// finalize commit
int err = lfsr_rbyd_appendcksum_(lfs, &mdir->rbyd, cksum);
if (err) {
return err;
}
// success?
// xor our new cksum
lfs->gcksum ^= mdir->rbyd.cksum;
return 0;
}
// TODO do we need to include commit overhead here?
static lfs_ssize_t lfsr_mdir_estimate__(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_srid_t start_rid, lfsr_srid_t end_rid,
lfsr_srid_t *split_rid_) {
// yet another function that is just begging to be deduplicated, but we
// can't because it would be recursive
//
// this is basically the same as lfsr_rbyd_estimate, except we assume all
// rids have weight 1 and have extra handling for opened files, shrubs, etc
// calculate dsize by starting from the outside ids and working inwards,
// this naturally gives us a split rid
lfsr_srid_t a_rid = lfs_smax(start_rid, -1);
lfsr_srid_t b_rid = lfs_min(mdir->rbyd.weight, end_rid);
lfs_size_t a_dsize = 0;
lfs_size_t b_dsize = 0;
lfs_size_t mdir_dsize = 0;
while (a_rid != b_rid) {
if (a_dsize > b_dsize
// bias so lower dsize >= upper dsize
|| (a_dsize == b_dsize && a_rid > b_rid)) {
LFS_SWAP(lfsr_srid_t, &a_rid, &b_rid);
LFS_SWAP(lfs_size_t, &a_dsize, &b_dsize);
}
if (a_rid > b_rid) {
a_rid -= 1;
}
lfsr_tag_t tag = 0;
lfs_size_t dsize_ = 0;
while (true) {
lfsr_srid_t rid_;
lfsr_data_t data;
int err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
a_rid, tag+1,
&rid_, &tag, NULL, &data);
if (err < 0) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
if (rid_ != a_rid) {
break;
}
// special handling for shrub trunks, we need to include the
// compacted cost of the shrub in our estimate
//
// this is what would make lfsr_rbyd_estimate recursive, and
// why we need a second function...
//
if (tag == LFSR_TAG_BSHRUB) {
// include the cost of this trunk
dsize_ += LFSR_SHRUB_DSIZE;
lfsr_shrub_t shrub;
err = lfsr_data_readshrub(lfs, &data, mdir, &shrub);
if (err < 0) {
return err;
}
lfs_ssize_t dsize__ = lfsr_shrub_estimate(lfs, &shrub);
if (dsize__ < 0) {
return dsize__;
}
dsize_ += lfs->rattr_estimate + dsize__;
} else {
// include the cost of this tag
dsize_ += lfs->mattr_estimate + lfsr_data_size(data);
}
}
// include any opened+unsynced inlined files
//
// this is O(n^2), but littlefs is unlikely to have many open
// files, I suppose if this becomes a problem we could sort
// opened files by mid
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
// belongs to our mdir + rid?
&& lfsr_mdir_cmp(&o->mdir, mdir) == 0
&& lfsr_mrid(lfs, o->mdir.mid) == a_rid
// is a bshrub?
&& lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)) {
lfs_ssize_t dsize__ = lfsr_shrub_estimate(lfs,
&((lfsr_bshrub_t*)o)->shrub);
if (dsize__ < 0) {
return dsize__;
}
dsize_ += dsize__;
}
}
if (a_rid <= -1) {
mdir_dsize += dsize_;
} else {
a_dsize += dsize_;
}
if (a_rid < b_rid) {
a_rid += 1;
}
}
if (split_rid_) {
*split_rid_ = a_rid;
}
return mdir_dsize + a_dsize + b_dsize;
}
static int lfsr_mdir_compact__(lfs_t *lfs, lfsr_mdir_t *mdir_,
const lfsr_mdir_t *mdir, lfsr_srid_t start_rid, lfsr_srid_t end_rid) {
// this is basically the same as lfsr_rbyd_compact, but with special
// handling for inlined trees.
//
// it's really tempting to deduplicate this via recursion! but we
// can't do that here
//
// TODO this true?
// note that any inlined updates here depend on the pre-commit state
// (btree), not the staged state (btree_), this is important,
// we can't trust btree_ after a failed commit
// assume we keep any gcksumdelta, this will get fixed the first time
// we commit anything
if (start_rid == -2) {
mdir_->gcksumdelta = mdir->gcksumdelta;
}
// copy over tags in the rbyd in order
lfsr_srid_t rid = lfs_smax(start_rid, -1);
lfsr_tag_t tag = 0;
while (true) {
lfsr_rid_t weight;
lfsr_data_t data;
int err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
rid, tag+1,
&rid, &tag, &weight, &data);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// end of range? note the use of rid+1 and unsigned comparison here to
// treat end_rid=-1 as "unbounded" in such a way that rid=-1 is still
// included
if ((lfs_size_t)(rid + 1) > (lfs_size_t)end_rid) {
break;
}
// found an inlined shrub? we need to compact the shrub as well to
// bring it along with us
if (tag == LFSR_TAG_BSHRUB) {
lfsr_shrub_t shrub;
err = lfsr_data_readshrub(lfs, &data, mdir,
&shrub);
if (err) {
return err;
}
// compact our shrub
err = lfsr_shrub_compact(lfs, &mdir_->rbyd, &shrub,
&shrub);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// write the new shrub tag
err = lfsr_rbyd_appendcompactrattr(lfs, &mdir_->rbyd,
LFSR_RATTR_SHRUB(tag, weight, &shrub));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
} else {
// write the tag
err = lfsr_rbyd_appendcompactrattr(lfs, &mdir_->rbyd,
LFSR_RATTR_DATA(tag, weight, &data));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
}
int err = lfsr_rbyd_appendcompaction(lfs, &mdir_->rbyd, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// we're not quite done! we also need to bring over any unsynced files
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)
// belongs to our mdir?
&& lfsr_mdir_cmp(&o->mdir, mdir) == 0
&& lfsr_mrid(lfs, o->mdir.mid) >= start_rid
&& (lfsr_rid_t)lfsr_mrid(lfs, o->mdir.mid)
< (lfsr_rid_t)end_rid
// is a bshrub?
&& lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)
// only compact once, first compact should
// stage the new block
&& ((lfsr_bshrub_t*)o)->shrub_.blocks[0]
!= mdir_->rbyd.blocks[0]) {
int err = lfsr_shrub_compact(lfs, &mdir_->rbyd,
&((lfsr_bshrub_t*)o)->shrub_,
&((lfsr_bshrub_t*)o)->shrub);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
}
return 0;
}
// mid-level mdir commit, this one will at least compact on overflow
static int lfsr_mdir_commit_(lfs_t *lfs, lfsr_mdir_t *mdir,
lfsr_srid_t start_rid, lfsr_srid_t end_rid,
lfsr_srid_t *split_rid_,
lfsr_smid_t mid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// make a copy
lfsr_mdir_t mdir_ = *mdir;
// mark as erased in case of failure
lfsr_mdir_claim(mdir);
// try to commit
int err = lfsr_mdir_commit__(lfs, &mdir_, start_rid, end_rid,
mid, rattrs, rattr_count);
if (err) {
if (err == LFS_ERR_RANGE || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
// update mdir
*mdir = mdir_;
return 0;
compact:;
// can't commit, can we compact?
bool relocated = false;
bool overrecyclable = true;
// check if we're within our compaction threshold
lfs_ssize_t estimate = lfsr_mdir_estimate__(lfs, mdir, start_rid, end_rid,
split_rid_);
if (estimate < 0) {
return estimate;
}
// TODO do we need to include mdir commit overhead here? in rbyd_estimate?
if ((lfs_size_t)estimate > lfs->cfg->block_size/2) {
return LFS_ERR_RANGE;
}
// swap blocks, increment revision count
err = lfsr_mdir_swap__(lfs, &mdir_, mdir, false);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
overrecyclable &= (err != LFS_ERR_CORRUPT);
goto relocate;
}
return err;
}
while (true) {
// try to compact
#ifdef LFS_DBGMDIRCOMMITS
LFS_DEBUG("Compacting mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"} "
"-> 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1],
mdir_.rbyd.blocks[0], mdir_.rbyd.blocks[1]);
#endif
// don't copy over gcksum if relocating
lfsr_srid_t start_rid_ = start_rid;
if (relocated) {
start_rid_ = lfs_smax(start_rid_, -1);
}
// compact our mdir
err = lfsr_mdir_compact__(lfs, &mdir_, mdir, start_rid_, end_rid);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
overrecyclable &= relocated;
goto relocate;
}
return err;
}
// now try to commit again
//
// upper layers should make sure this can't fail by limiting the
// maximum commit size
err = lfsr_mdir_commit__(lfs, &mdir_, start_rid_, end_rid,
mid, rattrs, rattr_count);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
overrecyclable &= relocated;
goto relocate;
}
return err;
}
// consume gcksumdelta if relocated
if (relocated) {
lfs->gcksum_d ^= mdir->gcksumdelta;
}
// update mdir
*mdir = mdir_;
return 0;
relocate:;
// needs relocation? bad prog? ok, try allocating a new mdir
err = lfsr_mdir_alloc__(lfs, &mdir_, mdir->mid, relocated);
if (err && !(err == LFS_ERR_NOSPC && overrecyclable)) {
return err;
}
relocated = true;
// no more blocks? wear-leveling falls apart here, but we can try
// without relocating
if (err == LFS_ERR_NOSPC) {
LFS_WARN("Overrecycling mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1]);
relocated = false;
overrecyclable = false;
err = lfsr_mdir_swap__(lfs, &mdir_, mdir, true);
if (err) {
// bad prog? can't do much here, mdir stuck
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Stuck mdir 0x{%"PRIx32",%"PRIx32"}",
mdir->rbyd.blocks[0],
mdir->rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
return err;
}
}
}
}
static int lfsr_mroot_parent(lfs_t *lfs, const lfs_block_t mptr[static 2],
lfsr_mdir_t *mparent_) {
// we only call this when we actually have parents
LFS_ASSERT(!lfsr_mptr_ismrootanchor(mptr));
// scan list of mroots for our requested pair
lfs_block_t mptr_[2] = {
LFSR_MPTR_MROOTANCHOR()[0],
LFSR_MPTR_MROOTANCHOR()[1]};
while (true) {
// fetch next possible superblock
lfsr_mdir_t mdir;
int err = lfsr_mdir_fetch(lfs, &mdir, -1, mptr_);
if (err) {
return err;
}
// lookup next mroot
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &mdir, LFSR_TAG_MROOT,
NULL, &data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// decode mdir
err = lfsr_data_readmptr(lfs, &data, mptr_);
if (err) {
return err;
}
// found our child?
if (lfsr_mptr_cmp(mptr_, mptr) == 0) {
*mparent_ = mdir;
return 0;
}
}
}
// needed in lfsr_mdir_commit
static inline void lfsr_file_discardleaf(lfsr_file_t *file);
// high-level mdir commit
//
// this is atomic and updates any opened mdirs, lfs_t, etc
//
// note that if an error occurs, any gstate is reverted to the on-disk
// state
//
static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
// non-mroot mdirs must have weight
LFS_ASSERT(mdir->mid == -1
// note inlined mdirs are mroots with mid != -1
|| lfsr_mdir_cmp(mdir, &lfs->mroot) == 0
|| mdir->rbyd.weight > 0);
// rid in-bounds?
LFS_ASSERT(lfsr_mrid(lfs, mdir->mid)
<= (lfsr_srid_t)mdir->rbyd.weight);
// lfs->mroot must have mid=-1
LFS_ASSERT(lfs->mroot.mid == -1);
// play out any rattrs that affect our grm _before_ committing to disk,
// keep in mind we revert to on-disk gstate if we run into an error
lfsr_smid_t mid_ = mdir->mid;
for (lfs_size_t i = 0; i < rattr_count; i++) {
// push a new grm, this tag lets us push grms atomically when
// creating new mids
if (rattrs[i].tag == LFSR_TAG_GRMPUSH) {
lfsr_grm_push(lfs, mid_);
// adjust pending grms?
} else {
for (int j = 0; j < 2; j++) {
if (lfsr_mbid(lfs, lfs->grm.queue[j]) == lfsr_mbid(lfs, mid_)
&& lfs->grm.queue[j] >= mid_) {
// deleting a pending grm doesn't really make sense
LFS_ASSERT(lfs->grm.queue[j] >= mid_ - rattrs[i].weight);
// adjust the grm
lfs->grm.queue[j] += rattrs[i].weight;
}
}
}
// adjust mid
mid_ = lfsr_rattr_nextrid(rattrs[i], mid_);
}
// flush gdeltas
lfsr_fs_flushgdelta(lfs);
// xor our old cksum
lfs->gcksum ^= mdir->rbyd.cksum;
// stage any bshrubs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_isbshrub(o->flags)) {
// a bshrub outside of its mdir means something has gone
// horribly wrong
LFS_ASSERT(!lfsr_bshrub_isbshrub((lfsr_bshrub_t*)o)
|| ((lfsr_bshrub_t*)o)->shrub.blocks[0]
== o->mdir.rbyd.blocks[0]);
((lfsr_bshrub_t*)o)->shrub_ = ((lfsr_bshrub_t*)o)->shrub;
}
}
// create a copy
lfsr_mdir_t mdir_[2];
mdir_[0] = *mdir;
// mark our mdir as unerased in case we fail
lfsr_mdir_claim(mdir);
// mark any copies of our mdir as unerased in case we fail
if (lfsr_mdir_cmp(mdir, &lfs->mroot) == 0) {
lfsr_mdir_claim(&lfs->mroot);
}
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_mdir_cmp(&o->mdir, mdir) == 0) {
lfsr_mdir_claim(&o->mdir);
}
}
// attempt to commit/compact the mdir normally
lfsr_srid_t split_rid;
int err = lfsr_mdir_commit_(lfs, &mdir_[0], -2, -1, &split_rid,
mdir->mid, rattrs, rattr_count);
if (err && err != LFS_ERR_RANGE
&& err != LFS_ERR_NOENT) {
goto failed;
}
// keep track of any mroot changes
lfsr_mdir_t mroot_ = lfs->mroot;
if (!err && lfsr_mdir_cmp(mdir, &lfs->mroot) == 0) {
lfsr_mdir_sync(&mroot_, &mdir_[0]);
}
// handle possible mtree updates, this gets a bit messy
lfsr_btree_t mtree_ = lfs->mtree;
lfsr_smid_t mdelta = 0;
// need to split?
if (err == LFS_ERR_RANGE) {
// this should not happen unless we can't fit our mroot's metadata
LFS_ASSERT(lfsr_mdir_cmp(mdir, &lfs->mroot) != 0
|| lfs->mtree.weight == 0);
// if we're not the mroot, we need to consume the gstate so
// we don't lose any info during the split
//
// we do this here so we don't have to worry about corner cases
// with dropping mdirs during a split
if (lfsr_mdir_cmp(mdir, &lfs->mroot) != 0) {
err = lfsr_fs_consumegdelta(lfs, mdir);
if (err) {
goto failed;
}
}
for (int i = 0; i < 2; i++) {
// order the split compacts so that that mdir containing our mid
// is committed last, this is a bit of a hack but necessary so
// shrubs are staged correctly
bool l = (lfsr_mrid(lfs, mdir->mid) < split_rid);
bool relocated = false;
split_relocate:;
// alloc and compact into new mdirs
err = lfsr_mdir_alloc__(lfs, &mdir_[i^l],
lfs_smax(mdir->mid, 0), relocated);
if (err) {
goto failed;
}
relocated = true;
err = lfsr_mdir_compact__(lfs, &mdir_[i^l],
mdir,
((i^l) == 0) ? 0 : split_rid,
((i^l) == 0) ? split_rid : -1);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate;
}
goto failed;
}
err = lfsr_mdir_commit__(lfs, &mdir_[i^l],
((i^l) == 0) ? 0 : split_rid,
((i^l) == 0) ? split_rid : -1,
mdir->mid, rattrs, rattr_count);
if (err && err != LFS_ERR_NOENT) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto split_relocate;
}
goto failed;
}
// empty? set weight to zero
if (err == LFS_ERR_NOENT) {
mdir_[i^l].rbyd.weight = 0;
}
}
// adjust our sibling's mid after committing rattrs
mdir_[1].mid += (1 << lfs->mbits);
LFS_INFO("Splitting mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"} "
"-> 0x{%"PRIx32",%"PRIx32"}, 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1],
mdir_[0].rbyd.blocks[0], mdir_[0].rbyd.blocks[1],
mdir_[1].rbyd.blocks[0], mdir_[1].rbyd.blocks[1]);
// because of defered commits, children can be reduced to zero
// when splitting, need to catch this here
// both siblings reduced to zero
if (mdir_[0].rbyd.weight == 0 && mdir_[1].rbyd.weight == 0) {
LFS_INFO("Dropping mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir_[0].mid),
mdir_[0].rbyd.blocks[0], mdir_[0].rbyd.blocks[1]);
LFS_INFO("Dropping mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir_[1].mid),
mdir_[1].rbyd.blocks[0], mdir_[1].rbyd.blocks[1]);
goto dropped;
// one sibling reduced to zero
} else if (mdir_[0].rbyd.weight == 0) {
LFS_INFO("Dropping mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir_[0].mid),
mdir_[0].rbyd.blocks[0], mdir_[0].rbyd.blocks[1]);
lfsr_mdir_sync(&mdir_[0], &mdir_[1]);
goto relocated;
// other sibling reduced to zero
} else if (mdir_[1].rbyd.weight == 0) {
LFS_INFO("Dropping mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir_[1].mid),
mdir_[1].rbyd.blocks[0], mdir_[1].rbyd.blocks[1]);
goto relocated;
}
// no siblings reduced to zero, update our mtree
mdelta = +(1 << lfs->mbits);
// lookup first name in sibling to use as the split name
//
// note we need to do this after playing out pending rattrs in
// case they introduce a new name!
lfsr_data_t split_name;
err = lfsr_rbyd_lookup(lfs, &mdir_[1].rbyd, 0,
LFSR_TAG_MASK8 | LFSR_TAG_NAME,
NULL, &split_name);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
goto failed;
}
// new mtree?
if (lfs->mtree.weight == 0) {
lfsr_btree_init(&mtree_);
err = lfsr_mtree_commit(lfs, &mtree_,
0, LFSR_RATTRS(
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, +(1 << lfs->mbits),
mdir_[0].rbyd.blocks),
LFSR_RATTR_DATA(
LFSR_TAG_MNAME, +(1 << lfs->mbits),
&split_name),
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, 0,
mdir_[1].rbyd.blocks)));
if (err) {
goto failed;
}
// update our mtree
} else {
// mark as unerased in case of failure
lfsr_btree_claim(&lfs->mtree);
err = lfsr_mtree_commit(lfs, &mtree_,
lfsr_mbid(lfs, mdir->mid), LFSR_RATTRS(
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, 0,
mdir_[0].rbyd.blocks),
LFSR_RATTR_DATA(
LFSR_TAG_MNAME, +(1 << lfs->mbits),
&split_name),
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, 0,
mdir_[1].rbyd.blocks)));
if (err) {
goto failed;
}
}
// need to drop?
} else if (err == LFS_ERR_NOENT) {
LFS_INFO("Dropping mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1]);
// set weight to zero
mdir_[0].rbyd.weight = 0;
// consume gstate so we don't lose any info
err = lfsr_fs_consumegdelta(lfs, mdir);
if (err) {
goto failed;
}
dropped:;
mdelta = -(1 << lfs->mbits);
// how can we drop if we have no mtree?
LFS_ASSERT(lfs->mtree.weight != 0);
// mark as unerased in case of failure
lfsr_btree_claim(&lfs->mtree);
// update our mtree
err = lfsr_mtree_commit(lfs, &mtree_,
lfsr_mbid(lfs, mdir->mid), LFSR_RATTRS(
LFSR_RATTR(
LFSR_TAG_RM, -(1 << lfs->mbits))));
if (err) {
goto failed;
}
// need to relocate?
} else if (lfsr_mdir_cmp(&mdir_[0], mdir) != 0
&& lfsr_mdir_cmp(mdir, &lfs->mroot) != 0) {
LFS_INFO("Relocating mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"} "
"-> 0x{%"PRIx32",%"PRIx32"}",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1],
mdir_[0].rbyd.blocks[0], mdir_[0].rbyd.blocks[1]);
relocated:;
// new mtree?
if (lfs->mtree.weight == 0) {
lfsr_btree_init(&mtree_);
err = lfsr_mtree_commit(lfs, &mtree_,
0, LFSR_RATTRS(
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, +(1 << lfs->mbits),
mdir_[0].rbyd.blocks)));
if (err) {
goto failed;
}
// update our mtree
} else {
// mark as unerased in case of failure
lfsr_btree_claim(&lfs->mtree);
err = lfsr_mtree_commit(lfs, &mtree_,
lfsr_mbid(lfs, mdir->mid), LFSR_RATTRS(
LFSR_RATTR_MPTR(
LFSR_TAG_MDIR, 0,
mdir_[0].rbyd.blocks)));
if (err) {
goto failed;
}
}
}
// patch any pending grms
for (int j = 0; j < 2; j++) {
if (lfsr_mbid(lfs, lfs->grm.queue[j])
== lfsr_mbid(lfs, lfs_smax(mdir->mid, 0))) {
if (mdelta > 0
&& lfsr_mrid(lfs, lfs->grm.queue[j])
>= (lfsr_srid_t)mdir_[0].rbyd.weight) {
lfs->grm.queue[j]
+= (1 << lfs->mbits) - mdir_[0].rbyd.weight;
}
} else if (lfs->grm.queue[j] > mdir->mid) {
lfs->grm.queue[j] += mdelta;
}
}
// need to update mtree?
if (lfsr_btree_cmp(&mtree_, &lfs->mtree) != 0) {
// mtree should never go to zero since we always have a root bookmark
LFS_ASSERT(mtree_.weight > 0);
// make sure mtree/mroot changes are on-disk before committing
// metadata
err = lfsr_bd_sync(lfs);
if (err) {
goto failed;
}
// xor mroot's cksum if we haven't already
if (lfsr_mdir_cmp(mdir, &lfs->mroot) != 0) {
lfs->gcksum ^= lfs->mroot.rbyd.cksum;
}
// mark any copies of our mroot as unerased
lfsr_mdir_claim(&lfs->mroot);
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_mdir_cmp(&o->mdir, &lfs->mroot) == 0) {
lfsr_mdir_claim(&o->mdir);
}
}
// commit new mtree into our mroot
//
// note end_rid=0 here will delete any files leftover from a split
// in our mroot
err = lfsr_mdir_commit_(lfs, &mroot_, -2, 0, NULL,
-1, LFSR_RATTRS(
LFSR_RATTR_BTREE(
LFSR_TAG_MASK8 | LFSR_TAG_MTREE, 0,
&mtree_),
// were we committing to the mroot? include any -1 rattrs
(mdir->mid == -1)
? LFSR_RATTR_RATTRS(rattrs, rattr_count)
: LFSR_RATTR_NOOP()));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
goto failed;
}
}
// need to update mroot chain?
if (lfsr_mdir_cmp(&mroot_, &lfs->mroot) != 0) {
// tail recurse, updating mroots until a commit sticks
lfsr_mdir_t mrootchild = lfs->mroot;
lfsr_mdir_t mrootchild_ = mroot_;
while (lfsr_mdir_cmp(&mrootchild_, &mrootchild) != 0
&& !lfsr_mdir_ismrootanchor(&mrootchild)) {
// find the mroot's parent
lfsr_mdir_t mrootparent_;
err = lfsr_mroot_parent(lfs, mrootchild.rbyd.blocks,
&mrootparent_);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
goto failed;
}
LFS_INFO("Relocating mroot 0x{%"PRIx32",%"PRIx32"} "
"-> 0x{%"PRIx32",%"PRIx32"}",
mrootchild.rbyd.blocks[0], mrootchild.rbyd.blocks[1],
mrootchild_.rbyd.blocks[0], mrootchild_.rbyd.blocks[1]);
mrootchild = mrootparent_;
// make sure mtree/mroot changes are on-disk before committing
// metadata
err = lfsr_bd_sync(lfs);
if (err) {
goto failed;
}
// xor mrootchild's cksum
lfs->gcksum ^= mrootparent_.rbyd.cksum;
// commit mrootchild
err = lfsr_mdir_commit_(lfs, &mrootparent_, -2, -1, NULL,
-1, LFSR_RATTRS(
LFSR_RATTR_MPTR(
LFSR_TAG_MROOT, 0,
mrootchild_.rbyd.blocks)));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
LFS_ASSERT(err != LFS_ERR_NOENT);
goto failed;
}
mrootchild_ = mrootparent_;
}
// no more mroot parents? uh oh, need to extend mroot chain
if (lfsr_mdir_cmp(&mrootchild_, &mrootchild) != 0) {
// mrootchild should be our previous mroot anchor at this point
LFS_ASSERT(lfsr_mdir_ismrootanchor(&mrootchild));
LFS_INFO("Extending mroot 0x{%"PRIx32",%"PRIx32"}"
" -> 0x{%"PRIx32",%"PRIx32"}, 0x{%"PRIx32",%"PRIx32"}",
mrootchild.rbyd.blocks[0], mrootchild.rbyd.blocks[1],
mrootchild.rbyd.blocks[0], mrootchild.rbyd.blocks[1],
mrootchild_.rbyd.blocks[0], mrootchild_.rbyd.blocks[1]);
// make sure mtree/mroot changes are on-disk before committing
// metadata
err = lfsr_bd_sync(lfs);
if (err) {
goto failed;
}
// commit the new mroot anchor
lfsr_mdir_t mrootanchor_;
err = lfsr_mdir_swap__(lfs, &mrootanchor_, &mrootchild, true);
if (err) {
// bad prog? can't do much here, mroot stuck
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Stuck mroot 0x{%"PRIx32",%"PRIx32"}",
mrootanchor_.rbyd.blocks[0],
mrootanchor_.rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
goto failed;
}
err = lfsr_mdir_commit__(lfs, &mrootanchor_, -2, -1,
-1, LFSR_RATTRS(
LFSR_RATTR_BUF(
LFSR_TAG_MAGIC, 0,
"littlefs", 8),
LFSR_RATTR_MPTR(
LFSR_TAG_MROOT, 0,
mrootchild_.rbyd.blocks)));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
LFS_ASSERT(err != LFS_ERR_NOENT);
// bad prog? can't do much here, mroot stuck
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Stuck mroot 0x{%"PRIx32",%"PRIx32"}",
mrootanchor_.rbyd.blocks[0],
mrootanchor_.rbyd.blocks[1]);
return LFS_ERR_NOSPC;
}
goto failed;
}
}
}
// sync on-disk state
err = lfsr_bd_sync(lfs);
if (err) {
return err;
}
///////////////////////////////////////////////////////////////////////
// success? update in-device state, we must not error at this point! //
///////////////////////////////////////////////////////////////////////
// play out any rattrs that affect internal state
mid_ = mdir->mid;
for (lfs_size_t i = 0; i < rattr_count; i++) {
// adjust any opened mdirs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// adjust opened mdirs?
if (lfsr_mdir_cmp(&o->mdir, mdir) == 0
&& o->mdir.mid >= mid_) {
// removed?
if (o->mdir.mid < mid_ - rattrs[i].weight) {
// we should not be removing opened regular files
LFS_ASSERT(lfsr_o_type(o->flags) != LFS_TYPE_REG);
o->flags |= LFS_o_ZOMBIE;
o->mdir.mid = mid_;
} else {
o->mdir.mid += rattrs[i].weight;
}
}
}
// adjust mid
mid_ = lfsr_rattr_nextrid(rattrs[i], mid_);
}
// if mroot/mtree changed, clobber any mroot/mtree traversals
if (lfsr_mdir_cmp(&mroot_, &lfs->mroot) != 0
|| lfsr_btree_cmp(&mtree_, &lfs->mtree) != 0) {
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_type(o->flags) == LFS_type_TRAVERSAL
&& o->mdir.mid == -1
// don't clobber the current mdir, assume upper layers
// know what they're doing
&& &o->mdir != mdir) {
lfsr_traversal_clobber(lfs, (lfsr_traversal_t*)o);
}
}
}
// update internal mdir state
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// avoid double updating the current mdir
if (&o->mdir == mdir) {
continue;
}
// update any splits/drops
if (lfsr_mdir_cmp(&o->mdir, mdir) == 0) {
if (mdelta > 0
&& lfsr_mrid(lfs, o->mdir.mid)
>= (lfsr_srid_t)mdir_[0].rbyd.weight) {
o->mdir.mid += (1 << lfs->mbits) - mdir_[0].rbyd.weight;
lfsr_mdir_sync(&o->mdir, &mdir_[1]);
} else {
lfsr_mdir_sync(&o->mdir, &mdir_[0]);
}
} else if (o->mdir.mid > mdir->mid) {
o->mdir.mid += mdelta;
}
}
// update mdir to follow requested rid
if (mdelta > 0
&& mdir->mid == -1) {
lfsr_mdir_sync(mdir, &mroot_);
} else if (mdelta > 0
&& lfsr_mrid(lfs, mdir->mid)
>= (lfsr_srid_t)mdir_[0].rbyd.weight) {
mdir->mid += (1 << lfs->mbits) - mdir_[0].rbyd.weight;
lfsr_mdir_sync(mdir, &mdir_[1]);
} else {
lfsr_mdir_sync(mdir, &mdir_[0]);
}
// update mroot and mtree
lfsr_mdir_sync(&lfs->mroot, &mroot_);
lfs->mtree = mtree_;
// update any staged bshrubs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// if we moved a shrub, we also need to discard any related
// leaves that moved
if (lfsr_o_type(o->flags) == LFS_TYPE_REG
&& lfsr_bptr_block(&((lfsr_file_t*)o)->leaf.bptr)
== ((lfsr_bshrub_t*)o)->shrub.blocks[0]
&& ((lfsr_bshrub_t*)o)->shrub_.blocks[0]
!= ((lfsr_bshrub_t*)o)->shrub.blocks[0]) {
lfsr_file_discardleaf((lfsr_file_t*)o);
}
// update the shrub
if (lfsr_o_isbshrub(o->flags)) {
((lfsr_bshrub_t*)o)->shrub = ((lfsr_bshrub_t*)o)->shrub_;
}
}
// update any gstate changes
lfsr_fs_commitgdelta(lfs);
// mark all traversals as dirty
lfsr_fs_clobber(lfs, LFS_t_DIRTY);
// we may have touched any number of mdirs, so assume uncompacted
// until lfsr_fs_gc can prove otherwise
lfs->flags |= LFS_I_COMPACT;
#ifdef LFS_DBGMDIRCOMMITS
LFS_DEBUG("Committed mdir %"PRId32" "
"0x{%"PRIx32",%"PRIx32"}.%"PRIx32" w%"PRId32", "
"cksum %"PRIx32,
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0], mdir->rbyd.blocks[1],
lfsr_rbyd_trunk(&mdir->rbyd),
mdir->rbyd.weight,
mdir->rbyd.cksum);
#endif
return 0;
failed:;
// revert gstate to on-disk state
lfsr_fs_revertgdelta(lfs);
return err;
}
static int lfsr_mdir_compact(lfs_t *lfs, lfsr_mdir_t *mdir) {
// the easiest way to do this is to just mark mdir as unerased
// and call lfsr_mdir_commit
lfsr_mdir_claim(mdir);
return lfsr_mdir_commit(lfs, mdir, NULL, 0);
}
/// Mtree path/name lookup ///
// lookup names in an mdir
//
// if not found, rid will be the best place to insert
static int lfsr_mdir_namelookup(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_did_t did, const char *name, lfs_size_t name_len,
lfsr_smid_t *mid_, lfsr_tag_t *tag_, lfsr_data_t *data_) {
// default to mid_ = 0, this blanket assignment is the only way to
// keep GCC happy
if (mid_) {
*mid_ = 0;
}
// empty mdir?
if (mdir->rbyd.weight == 0) {
return LFS_ERR_NOENT;
}
lfsr_srid_t rid;
lfsr_tag_t tag;
lfs_scmp_t cmp = lfsr_rbyd_namelookup(lfs, &mdir->rbyd,
did, name, name_len,
&rid, &tag, NULL, data_);
if (cmp < 0) {
LFS_ASSERT(cmp != LFS_ERR_NOENT);
return cmp;
}
// adjust mid if necessary
//
// note missing mids end up pointing to the next mid
lfsr_smid_t mid = LFSR_MID(lfs,
mdir->mid,
(cmp < LFS_CMP_EQ) ? rid+1 : rid);
// map name tags to understood types
tag = lfsr_mdir_nametag(lfs, mdir, mid, tag);
if (mid_) {
*mid_ = mid;
}
if (tag_) {
*tag_ = tag;
}
return (cmp == LFS_CMP_EQ) ? 0 : LFS_ERR_NOENT;
}
// lookup names in our mtree
//
// if not found, rid will be the best place to insert
static int lfsr_mtree_namelookup(lfs_t *lfs,
lfsr_did_t did, const char *name, lfs_size_t name_len,
lfsr_mdir_t *mdir_, lfsr_tag_t *tag_, lfsr_data_t *data_) {
// do we only have mroot?
if (lfs->mtree.weight == 0) {
// treat inlined mdir as mid=0
mdir_->mid = 0;
lfsr_mdir_sync(mdir_, &lfs->mroot);
// lookup name in actual mtree
} else {
lfsr_bid_t bid;
lfsr_srid_t rid;
lfsr_tag_t tag;
lfsr_bid_t weight;
lfsr_data_t data;
lfs_scmp_t cmp = lfsr_btree_namelookupleaf(lfs, &lfs->mtree,
did, name, name_len,
&bid, &mdir_->rbyd, &rid, &tag, &weight, &data);
if (cmp < 0) {
LFS_ASSERT(cmp != LFS_ERR_NOENT);
return cmp;
}
LFS_ASSERT(weight == (lfsr_bid_t)(1 << lfs->mbits));
LFS_ASSERT(tag == LFSR_TAG_MNAME
|| tag == LFSR_TAG_MDIR);
// if we found an mname, lookup the mdir
if (tag == LFSR_TAG_MNAME) {
int err = lfsr_rbyd_lookup(lfs, &mdir_->rbyd, rid, LFSR_TAG_MDIR,
NULL, &data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// fetch mdir
int err = lfsr_data_fetchmdir(lfs, &data, bid-((1 << lfs->mbits)-1),
mdir_);
if (err) {
return err;
}
}
// and lookup name in our mdir
lfsr_smid_t mid;
int err = lfsr_mdir_namelookup(lfs, mdir_, did, name, name_len,
&mid, tag_, data_);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// update mdir with best place to insert even if we fail
mdir_->mid = mid;
return err;
}
// special directory-ids
enum {
LFSR_DID_ROOT = 0,
};
// some operations on paths
static inline lfs_size_t lfsr_path_namelen(const char *path) {
return lfs_strcspn(path, "/");
}
static inline bool lfsr_path_islast(const char *path) {
lfs_size_t name_len = lfsr_path_namelen(path);
return path[name_len + lfs_strspn(path + name_len, "/")] == '\0';
}
static inline bool lfsr_path_isdir(const char *path) {
return path[lfsr_path_namelen(path)] != '\0';
}
// lookup a full path in our mtree, updating the path as we descend
//
// the errors get a bit subtle here, and rely on what ends up in the
// path/mdir:
// - 0 => file found
// - 0, lfsr_path_isdir(path) => dir found
// - 0, mdir.mid=-1 => root found
// - LFS_ERR_NOENT, lfsr_path_islast(path) => file not found
// - LFS_ERR_NOENT, !lfsr_path_islast(path) => parent not found
// - LFS_ERR_NOTDIR => parent not a dir
//
// if not found, mdir/did_ will at least be set up with what should be
// the parent
//
static int lfsr_mtree_pathlookup(lfs_t *lfs, const char **path,
lfsr_mdir_t *mdir_, lfsr_tag_t *tag_, lfsr_did_t *did_) {
// setup root
*mdir_ = lfs->mroot;
lfsr_tag_t tag = LFSR_TAG_DIR;
lfsr_did_t did = LFSR_DID_ROOT;
// we reduce path to a single name if we can find it
const char *path_ = *path;
// empty paths are not allowed
if (path_[0] == '\0') {
return LFS_ERR_INVAL;
}
while (true) {
// skip slashes if we're a directory
if (tag == LFSR_TAG_DIR) {
path_ += lfs_strspn(path_, "/");
}
lfs_size_t name_len = lfs_strcspn(path_, "/");
// skip '.'
if (name_len == 1 && lfs_memcmp(path_, ".", 1) == 0) {
path_ += name_len;
goto next;
}
// error on unmatched '..', trying to go above root, eh?
if (name_len == 2 && lfs_memcmp(path_, "..", 2) == 0) {
return LFS_ERR_INVAL;
}
// skip if matched by '..' in name
const char *suffix = path_ + name_len;
lfs_size_t suffix_len;
int depth = 1;
while (true) {
suffix += lfs_strspn(suffix, "/");
suffix_len = lfs_strcspn(suffix, "/");
if (suffix_len == 0) {
break;
}
if (suffix_len == 1 && lfs_memcmp(suffix, ".", 1) == 0) {
// noop
} else if (suffix_len == 2 && lfs_memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
path_ = suffix + suffix_len;
goto next;
}
} else {
depth += 1;
}
suffix += suffix_len;
}
// found end of path, we must be done parsing our path now
if (path_[0] == '\0') {
if (tag_) {
*tag_ = tag;
}
if (did_) {
*did_ = did;
}
return 0;
}
// only continue if we hit a directory
if (tag != LFSR_TAG_DIR) {
return (tag == LFSR_TAG_ORPHAN)
? LFS_ERR_NOENT
: LFS_ERR_NOTDIR;
}
// read the next did from the mdir if this is not the root
if (mdir_->mid != -1) {
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, mdir_, LFSR_TAG_DID,
NULL, &data);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, &data, &did);
if (err) {
return err;
}
}
// update path as we parse
*path = path_;
// lookup up this name in the mtree
int err = lfsr_mtree_namelookup(lfs, did, path_, name_len,
mdir_, &tag, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// keep track of where to insert if we can't find path
if (err == LFS_ERR_NOENT) {
if (tag_) {
*tag_ = tag;
}
if (did_) {
*did_ = did;
}
return LFS_ERR_NOENT;
}
// go on to next name
path_ += name_len;
next:;
}
}
/// Mtree traversal ///
// traversing littlefs is a bit complex, so we use a state machine to keep
// track of where we are
enum {
LFSR_TSTATE_MROOTANCHOR = 0,
LFSR_TSTATE_MROOTCHAIN = 1,
LFSR_TSTATE_MTREE = 2,
LFSR_TSTATE_MDIRS = 3,
LFSR_TSTATE_MDIR = 4,
LFSR_TSTATE_BTREE = 5,
LFSR_TSTATE_OMDIRS = 6,
LFSR_TSTATE_OBTREE = 7,
LFSR_TSTATE_DONE = 8,
};
static void lfsr_traversal_init(lfsr_traversal_t *t, uint32_t flags) {
t->b.o.flags = lfsr_o_typeflags(LFS_type_TRAVERSAL)
| lfsr_t_tstateflags(LFSR_TSTATE_MROOTANCHOR)
| flags;
t->b.o.mdir.mid = -1;
t->b.o.mdir.rbyd.weight = 0;
t->b.o.mdir.rbyd.blocks[0] = -1;
t->b.o.mdir.rbyd.blocks[1] = -1;
lfsr_bshrub_init(&t->b);
t->ot = NULL;
t->u.mtortoise.blocks[0] = -1;
t->u.mtortoise.blocks[1] = -1;
t->u.mtortoise.step = 0;
t->u.mtortoise.power = 0;
t->gcksum = 0;
}
// needed in lfsr_mtree_traverse_
static int lfsr_file_traverse_(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_btraversal_t *bt,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_bptr_t *bptr);
// low-level traversal _only_ finds blocks
static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_traversal_t *t,
lfsr_tag_t *tag_, lfsr_bptr_t *bptr) {
while (true) {
switch (lfsr_t_tstate(t->b.o.flags)) {
// start with the mrootanchor 0x{0,1}
//
// note we make sure to include all mroots in our mroot chain!
//
case LFSR_TSTATE_MROOTANCHOR:;
// fetch the first mroot 0x{0,1}
int err = lfsr_mdir_fetch(lfs, &t->b.o.mdir,
-1, LFSR_MPTR_MROOTANCHOR());
if (err) {
return err;
}
// transition to traversing the mroot chain
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MROOTCHAIN);
if (tag_) {
*tag_ = LFSR_TAG_MDIR;
}
bptr->data.u.buffer = (const uint8_t*)&t->b.o.mdir;
return 0;
// traverse the mroot chain, checking for mroots/mtrees
case LFSR_TSTATE_MROOTCHAIN:;
// lookup mroot, if we find one this is not the active mroot
lfsr_tag_t tag;
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &t->b.o.mdir,
LFSR_TAG_MASK8 | LFSR_TAG_STRUCT,
&tag, &data);
if (err) {
// if we have no mtree (inlined mdir), we need to
// traverse any files in our mroot next
if (err == LFS_ERR_NOENT) {
t->b.o.mdir.mid = 0;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIR);
continue;
}
return err;
}
// found a new mroot
if (tag == LFSR_TAG_MROOT) {
// fetch this mroot
err = lfsr_data_fetchmdir(lfs, &data, -1,
&t->b.o.mdir);
if (err) {
return err;
}
// detect cycles with Brent's algorithm
//
// note we only check for cycles in the mroot chain, the
// btree inner nodes require checksums of their pointers,
// so creating a valid cycle is actually quite difficult
//
if (lfsr_mptr_cmp(
t->b.o.mdir.rbyd.blocks,
t->u.mtortoise.blocks) == 0) {
LFS_ERROR("Cycle detected during mtree traversal "
"0x{%"PRIx32",%"PRIx32"}",
t->b.o.mdir.rbyd.blocks[0],
t->b.o.mdir.rbyd.blocks[1]);
return LFS_ERR_CORRUPT;
}
if (t->u.mtortoise.step == (1U << t->u.mtortoise.power)) {
t->u.mtortoise.blocks[0] = t->b.o.mdir.rbyd.blocks[0];
t->u.mtortoise.blocks[1] = t->b.o.mdir.rbyd.blocks[1];
t->u.mtortoise.step = 0;
t->u.mtortoise.power += 1;
}
t->u.mtortoise.step += 1;
if (tag_) {
*tag_ = LFSR_TAG_MDIR;
}
bptr->data.u.buffer = (const uint8_t*)&t->b.o.mdir;
return 0;
// found an mtree?
} else if (tag == LFSR_TAG_MTREE) {
// fetch the root of the mtree
err = lfsr_data_fetchbtree(lfs, &data,
&t->b.shrub);
if (err) {
return err;
}
// transition to traversing the mtree
lfsr_btraversal_init(&t->u.bt);
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MTREE);
continue;
} else {
LFS_ERROR("Weird mroot entry? 0x%"PRIx32, tag);
return LFS_ERR_CORRUPT;
}
LFS_UNREACHABLE();
// iterate over mdirs in the mtree
case LFSR_TSTATE_MDIRS:;
// find the next mdir
err = lfsr_mtree_lookup(lfs, t->b.o.mdir.mid,
&t->b.o.mdir);
if (err) {
// end of mtree? guess we're done
if (err == LFS_ERR_NOENT) {
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_DONE);
continue;
}
return err;
}
// transition to traversing the mdir
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIR);
if (tag_) {
*tag_ = LFSR_TAG_MDIR;
}
bptr->data.u.buffer = (const uint8_t*)&t->b.o.mdir;
return 0;
// scan for blocks/btrees in the current mdir
case LFSR_TSTATE_MDIR:;
// not traversing all blocks? have we exceeded our mdir's weight?
// return to mtree iteration
if (lfsr_t_ismtreeonly(t->b.o.flags)
|| lfsr_mrid(lfs, t->b.o.mdir.mid)
>= (lfsr_srid_t)t->b.o.mdir.rbyd.weight) {
t->b.o.mdir.mid = lfsr_mbid(lfs, t->b.o.mdir.mid) + 1;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIRS);
continue;
}
// do we have a bshrub/btree?
err = lfsr_mdir_lookup(lfs, &t->b.o.mdir,
LFSR_TAG_MASK8 | LFSR_TAG_STRUCT,
&tag, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// found a bshrub/btree? note we may also run into
// dirs/dids here
if (err != LFS_ERR_NOENT
&& (tag == LFSR_TAG_BSHRUB
|| tag == LFSR_TAG_BTREE)) {
// found a bshrub (inlined btree)?
if (tag == LFSR_TAG_BSHRUB) {
err = lfsr_data_readshrub(lfs, &data, &t->b.o.mdir,
&t->b.shrub);
if (err) {
return err;
}
// found a btree?
} else if (tag == LFSR_TAG_BTREE) {
err = lfsr_data_fetchbtree(lfs, &data,
&t->b.shrub);
if (err) {
return err;
}
} else {
LFS_UNREACHABLE();
}
// start traversing
lfsr_btraversal_init(&t->u.bt);
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_BTREE);
continue;
// no? next we need to check any opened files
} else {
t->ot = lfs->omdirs;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_OMDIRS);
continue;
}
LFS_UNREACHABLE();
// scan for blocks/btrees in our opened file list
case LFSR_TSTATE_OMDIRS:;
// reached end of opened files? return to mdir traversal
if (!t->ot) {
t->b.o.mdir.mid += 1;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIR);
continue;
}
// skip unrelated files, we only care about unsync reg files
// associated with the current mid
//
// we traverse mids separately to make recovery from clobbered
// traversals easier, which means this grows O(n^2) if you have
// literally every file open, but other things grow O(n^2) with
// this list anyways
//
if (t->ot->mdir.mid != t->b.o.mdir.mid
|| lfsr_o_type(t->ot->flags) != LFS_TYPE_REG
|| !lfsr_o_isunsync(t->ot->flags)) {
t->ot = t->ot->next;
continue;
}
// transition to traversing the file
const lfsr_file_t *file = (const lfsr_file_t*)t->ot;
t->b.shrub = file->b.shrub;
lfsr_btraversal_init(&t->u.bt);
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_OBTREE);
// wait, do we have an ungrafted leaf?
if (lfsr_o_isungraft(file->b.o.flags)) {
if (tag_) {
*tag_ = LFSR_TAG_BLOCK;
}
*bptr = file->leaf.bptr;
return 0;
}
continue;
// traverse any bshrubs/btrees we see, this includes the mtree
// and any file btrees/bshrubs
case LFSR_TSTATE_MTREE:;
case LFSR_TSTATE_BTREE:;
case LFSR_TSTATE_OBTREE:;
// traverse through our bshrub/btree
//
// it probably looks a bit weird to go through
// lfsr_file_traverse_, but this gets us bptr decoding
// for free
err = lfsr_file_traverse_(lfs, &t->b, &t->u.bt,
NULL, &tag, bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
// clear the bshrub state
lfsr_bshrub_init(&t->b);
// end of mtree? start iterating over mdirs
if (lfsr_t_tstate(t->b.o.flags)
== LFSR_TSTATE_MTREE) {
t->b.o.mdir.mid = 0;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIRS);
continue;
// end of mdir btree? start iterating over opened files
} else if (lfsr_t_tstate(t->b.o.flags)
== LFSR_TSTATE_BTREE) {
t->ot = lfs->omdirs;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_OMDIRS);
continue;
// end of opened btree? go to next opened file
} else if (lfsr_t_tstate(t->b.o.flags)
== LFSR_TSTATE_OBTREE) {
t->ot = t->ot->next;
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_OMDIRS);
continue;
} else {
LFS_UNREACHABLE();
}
}
return err;
}
// found an inner btree node?
if (tag == LFSR_TAG_BRANCH) {
if (tag_) {
*tag_ = tag;
}
return 0;
// found an indirect block?
} else if (tag == LFSR_TAG_BLOCK) {
if (tag_) {
*tag_ = tag;
}
return 0;
}
continue;
case LFSR_TSTATE_DONE:;
return LFS_ERR_NOENT;
default:;
LFS_UNREACHABLE();
}
}
}
// needed in lfsr_mtree_traverse
static void lfs_alloc_markinuse(lfs_t *lfs,
lfsr_tag_t tag, const lfsr_bptr_t *bptr);
// high-level immutable traversal, handle extra features here,
// but no mutation! (we're called in lfs_alloc, so things would end up
// recursive, which would be a bit bad!)
static int lfsr_mtree_traverse(lfs_t *lfs, lfsr_traversal_t *t,
lfsr_tag_t *tag_, lfsr_bptr_t *bptr) {
lfsr_tag_t tag;
int err = lfsr_mtree_traverse_(lfs, t,
&tag, bptr);
if (err) {
// end of traversal?
if (err == LFS_ERR_NOENT) {
goto eot;
}
return err;
}
// validate mdirs? mdir checksums are already validated in
// lfsr_mdir_fetch, but this doesn't prevent rollback issues, where
// the most recent commit is corrupted but a previous outdated
// commit appears valid
//
// this is where the gcksum comes in, which we can recalculate to
// check if the filesystem state on-disk is as expected
//
// we also compare mdir checksums with any open mdirs to try to
// avoid traversing any outdated bshrubs/btrees
if ((lfsr_t_isckmeta(t->b.o.flags)
|| lfsr_t_isckdata(t->b.o.flags))
&& tag == LFSR_TAG_MDIR) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr->data.u.buffer;
// check cksum matches our mroot
if (lfsr_mdir_cmp(mdir, &lfs->mroot) == 0
&& mdir->rbyd.cksum != lfs->mroot.rbyd.cksum) {
LFS_ERROR("Found mroot cksum mismatch "
"0x{%"PRIx32",%"PRIx32"}, "
"cksum %08"PRIx32" (!= %08"PRIx32")",
mdir->rbyd.blocks[0],
mdir->rbyd.blocks[1],
mdir->rbyd.cksum,
lfs->mroot.rbyd.cksum);
return LFS_ERR_CORRUPT;
}
// check cksum matches any open mdirs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_mdir_cmp(&o->mdir, mdir) == 0
&& o->mdir.rbyd.cksum != mdir->rbyd.cksum) {
LFS_ERROR("Found mdir cksum mismatch %"PRId32" "
"0x{%"PRIx32",%"PRIx32"}, "
"cksum %08"PRIx32" (!= %08"PRIx32")",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0],
mdir->rbyd.blocks[1],
mdir->rbyd.cksum,
o->mdir.rbyd.cksum);
return LFS_ERR_CORRUPT;
}
}
// recalculate gcksum
t->gcksum ^= mdir->rbyd.cksum;
}
// validate btree nodes?
//
// this may end up revalidating some btree nodes when ckfetches
// is enabled, but we need to revalidate cached btree nodes or
// we risk missing errors in ckmeta scans
if ((lfsr_t_isckmeta(t->b.o.flags)
|| lfsr_t_isckdata(t->b.o.flags))
&& tag == LFSR_TAG_BRANCH) {
lfsr_rbyd_t *rbyd = (lfsr_rbyd_t*)bptr->data.u.buffer;
err = lfsr_rbyd_fetchck(lfs, rbyd,
rbyd->blocks[0], rbyd->trunk,
rbyd->cksum);
if (err) {
return err;
}
}
// validate data blocks?
if (lfsr_t_isckdata(t->b.o.flags)
&& tag == LFSR_TAG_BLOCK) {
err = lfsr_bptr_ck(lfs, bptr);
if (err) {
return err;
}
}
if (tag_) {
*tag_ = tag;
}
return 0;
eot:;
// compare gcksum with in-RAM gcksum
if ((lfsr_t_isckmeta(t->b.o.flags)
|| lfsr_t_isckdata(t->b.o.flags))
&& !lfsr_t_isdirty(t->b.o.flags)
&& !lfsr_t_ismutated(t->b.o.flags)
&& t->gcksum != lfs->gcksum) {
LFS_ERROR("Found gcksum mismatch, cksum %08"PRIx32" (!= %08"PRIx32")",
t->gcksum,
lfs->gcksum);
return LFS_ERR_CORRUPT;
}
// was ckmeta/ckdata successful? we only consider our filesystem
// checked if we weren't mutated
if ((lfsr_t_isckmeta(t->b.o.flags)
|| lfsr_t_isckdata(t->b.o.flags))
&& !lfsr_t_ismtreeonly(t->b.o.flags)
&& !lfsr_t_isdirty(t->b.o.flags)
&& !lfsr_t_ismutated(t->b.o.flags)) {
lfs->flags &= ~LFS_I_CKMETA;
}
if (lfsr_t_isckdata(t->b.o.flags)
&& !lfsr_t_ismtreeonly(t->b.o.flags)
&& !lfsr_t_isdirty(t->b.o.flags)
&& !lfsr_t_ismutated(t->b.o.flags)) {
lfs->flags &= ~LFS_I_CKDATA;
}
return LFS_ERR_NOENT;
}
// needed in lfsr_mtree_gc
static int lfsr_mdir_mkconsistent(lfs_t *lfs, lfsr_mdir_t *mdir);
static void lfs_alloc_ckpoint(lfs_t *lfs);
static void lfs_alloc_markfree(lfs_t *lfs);
// high-level mutating traversal, handle extra features that require
// mutation here, upper layers should call lfs_alloc_ckpoint as needed
static int lfsr_mtree_gc(lfs_t *lfs, lfsr_traversal_t *t,
lfsr_tag_t *tag_, lfsr_bptr_t *bptr) {
dropped:;
lfsr_tag_t tag;
int err = lfsr_mtree_traverse(lfs, t,
&tag, bptr);
if (err) {
// end of traversal?
if (err == LFS_ERR_NOENT) {
goto eot;
}
goto failed;
}
// swap dirty/mutated flags while in lfsr_mtree_gc
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
// track in-use blocks?
if (lfsr_t_islookahead(t->b.o.flags)) {
lfs_alloc_markinuse(lfs, tag, bptr);
}
// mkconsistencing mdirs?
if (lfsr_t_ismkconsistent(t->b.o.flags)
&& lfsr_t_ismkconsistent(lfs->flags)
&& tag == LFSR_TAG_MDIR) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr->data.u.buffer;
err = lfsr_mdir_mkconsistent(lfs, mdir);
if (err) {
goto failed;
}
// make sure we clear any zombie flags
t->b.o.flags &= ~LFS_o_ZOMBIE;
// did this drop our mdir?
if (mdir->mid != -1 && mdir->rbyd.weight == 0) {
// swap back dirty/mutated flags
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
// continue traversal
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIRS);
goto dropped;
}
}
// compacting mdirs?
if (lfsr_t_iscompact(t->b.o.flags)
&& tag == LFSR_TAG_MDIR
// exceed compaction threshold?
&& lfsr_rbyd_eoff(&((lfsr_mdir_t*)bptr->data.u.buffer)->rbyd)
> ((lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8)) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr->data.u.buffer;
LFS_INFO("Compacting mdir %"PRId32" 0x{%"PRIx32",%"PRIx32"} "
"(%"PRId32" > %"PRId32")",
lfsr_dbgmbid(lfs, mdir->mid),
mdir->rbyd.blocks[0],
mdir->rbyd.blocks[1],
lfsr_rbyd_eoff(&mdir->rbyd),
(lfs->cfg->gc_compact_thresh)
? lfs->cfg->gc_compact_thresh
: lfs->cfg->block_size - lfs->cfg->block_size/8);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// compact the mdir
err = lfsr_mdir_compact(lfs, mdir);
if (err) {
goto failed;
}
}
// swap back dirty/mutated flags
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
if (tag_) {
*tag_ = tag;
}
return 0;
eot:;
// was lookahead scan successful?
if (lfsr_t_islookahead(t->b.o.flags)
&& !lfsr_t_ismtreeonly(t->b.o.flags)
&& !lfsr_t_isdirty(t->b.o.flags)
&& !lfsr_t_ismutated(t->b.o.flags)) {
lfs_alloc_markfree(lfs);
}
// was mkconsistent successful?
if (lfsr_t_ismkconsistent(t->b.o.flags)
&& !lfsr_t_isdirty(t->b.o.flags)) {
lfs->flags &= ~LFS_I_MKCONSISTENT;
}
// was compaction successful? note we may need multiple passes if
// we want to be sure everything is compacted
if (lfsr_t_iscompact(t->b.o.flags)
&& !lfsr_t_isdirty(t->b.o.flags)
&& !lfsr_t_ismutated(t->b.o.flags)) {
lfs->flags &= ~LFS_I_COMPACT;
}
return LFS_ERR_NOENT;
failed:;
// swap back dirty/mutated flags
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
return err;
}
/// Block allocator ///
// checkpoint the allocator
//
// operations that need to alloc should call this to indicate all in-use
// blocks are either committed into the filesystem or tracked by an opened
// mdir
static void lfs_alloc_ckpoint(lfs_t *lfs) {
lfs->lookahead.ckpoint = lfs->block_count;
}
// discard any lookahead state, this is necessary if block_count changes
static void lfs_alloc_discard(lfs_t *lfs) {
lfs->lookahead.size = 0;
lfs_memset(lfs->lookahead.buffer, 0, lfs->cfg->lookahead_size);
}
// mark a block as in-use
static void lfs_alloc_markinuse_(lfs_t *lfs, lfs_block_t block) {
// translate to lookahead-relative
lfs_block_t block_ = ((
(lfs_sblock_t)(block
- (lfs->lookahead.window + lfs->lookahead.off))
// we only need this mess because C's mod is actually rem, and
// we want real mod in case block_ goes negative
% (lfs_sblock_t)lfs->block_count)
+ (lfs_sblock_t)lfs->block_count)
% (lfs_sblock_t)lfs->block_count;
if (block_ < 8*lfs->cfg->lookahead_size) {
// mark as in-use
lfs->lookahead.buffer[
((lfs->lookahead.off + block_) / 8)
% lfs->cfg->lookahead_size]
|= 1 << ((lfs->lookahead.off + block_) % 8);
}
}
// mark some filesystem object as in-use
static void lfs_alloc_markinuse(lfs_t *lfs,
lfsr_tag_t tag, const lfsr_bptr_t *bptr) {
if (tag == LFSR_TAG_MDIR) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr->data.u.buffer;
lfs_alloc_markinuse_(lfs, mdir->rbyd.blocks[0]);
lfs_alloc_markinuse_(lfs, mdir->rbyd.blocks[1]);
} else if (tag == LFSR_TAG_BRANCH) {
lfsr_rbyd_t *rbyd = (lfsr_rbyd_t*)bptr->data.u.buffer;
lfs_alloc_markinuse_(lfs, rbyd->blocks[0]);
} else if (tag == LFSR_TAG_BLOCK) {
lfs_alloc_markinuse_(lfs, lfsr_bptr_block(bptr));
} else {
LFS_UNREACHABLE();
}
}
// needed in lfs_alloc_markfree
static lfs_sblock_t lfs_alloc_findfree(lfs_t *lfs);
// mark any not-in-use blocks as free
static void lfs_alloc_markfree(lfs_t *lfs) {
// make lookahead buffer usable
lfs->lookahead.size = lfs_min(
8*lfs->cfg->lookahead_size,
lfs->lookahead.ckpoint);
// signal that lookahead is full, this may be cleared by
// lfs_alloc_findfree
lfs->flags &= ~LFS_I_LOOKAHEAD;
// eagerly find the next free block so lookahead scans can make
// the most progress
lfs_alloc_findfree(lfs);
}
// increment lookahead buffer
static void lfs_alloc_inc(lfs_t *lfs) {
LFS_ASSERT(lfs->lookahead.size > 0);
// clear lookahead as we increment
lfs->lookahead.buffer[lfs->lookahead.off / 8]
&= ~(1 << (lfs->lookahead.off % 8));
// signal that lookahead is no longer full
lfs->flags |= LFS_I_LOOKAHEAD;
// increment next/off
lfs->lookahead.off += 1;
if (lfs->lookahead.off == 8*lfs->cfg->lookahead_size) {
lfs->lookahead.off = 0;
lfs->lookahead.window = (lfs->lookahead.window
+ 8*lfs->cfg->lookahead_size)
% lfs->block_count;
}
// decrement size/ckpoint
lfs->lookahead.size -= 1;
lfs->lookahead.ckpoint -= 1;
}
// find next free block in lookahead buffer, if there is one
static lfs_sblock_t lfs_alloc_findfree(lfs_t *lfs) {
while (lfs->lookahead.size > 0) {
if (!(lfs->lookahead.buffer[lfs->lookahead.off / 8]
& (1 << (lfs->lookahead.off % 8)))) {
// found a free block
return (lfs->lookahead.window + lfs->lookahead.off)
% lfs->block_count;
}
lfs_alloc_inc(lfs);
}
return LFS_ERR_NOSPC;
}
static lfs_sblock_t lfs_alloc(lfs_t *lfs, bool erase) {
while (true) {
// scan our lookahead buffer for free blocks
lfs_sblock_t block = lfs_alloc_findfree(lfs);
if (block < 0 && block != LFS_ERR_NOSPC) {
return block;
}
if (block != LFS_ERR_NOSPC) {
// we should never alloc blocks {0,1}
LFS_ASSERT(block != 0 && block != 1);
// erase requested?
if (erase) {
int err = lfsr_bd_erase(lfs, block);
if (err) {
// bad erase? try another block
if (err == LFS_ERR_CORRUPT) {
lfs_alloc_inc(lfs);
continue;
}
return err;
}
}
// eagerly find the next free block to maximize how many blocks
// lfs_alloc_ckpoint makes available for scanning
lfs_alloc_inc(lfs);
lfs_alloc_findfree(lfs);
#ifdef LFS_DBGALLOCS
LFS_DEBUG("Allocated block 0x%"PRIx32", "
"lookahead %"PRId32"/%"PRId32"/%"PRId32,
block,
lfs->lookahead.size,
lfs->lookahead.ckpoint,
lfs->cfg->block_count);
#endif
return block;
}
// in order to keep our block allocator from spinning forever when our
// filesystem is full, we mark points where there are no in-flight
// allocations with a checkpoint before starting a set of allocations
//
// if we've looked at all blocks since the last checkpoint, we report
// the filesystem as out of storage
//
if (lfs->lookahead.ckpoint <= 0) {
LFS_ERROR("No more free space "
"(lookahead %"PRId32"/%"PRId32"/%"PRId32")",
lfs->lookahead.size,
lfs->lookahead.ckpoint,
lfs->cfg->block_count);
return LFS_ERR_NOSPC;
}
// no blocks in our lookahead buffer?
//
// traverse the filesystem, building up knowledge of what blocks are
// in-use in the next lookahead window
//
lfsr_traversal_t t;
lfsr_traversal_init(&t, LFS_T_RDONLY | LFS_T_LOOKAHEAD);
while (true) {
lfsr_tag_t tag;
lfsr_bptr_t bptr;
int err = lfsr_mtree_traverse(lfs, &t,
&tag, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// track in-use blocks
lfs_alloc_markinuse(lfs, tag, &bptr);
}
// mark anything not seen as free
lfs_alloc_markfree(lfs);
}
}
/// Directory operations ///
int lfsr_mkdir(lfs_t *lfs, const char *path) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
// lookup our parent
lfsr_mdir_t mdir;
lfsr_tag_t tag;
lfsr_did_t did;
err = lfsr_mtree_pathlookup(lfs, &path,
&mdir, &tag, &did);
if (err && !(err == LFS_ERR_NOENT && lfsr_path_islast(path))) {
return err;
}
// already exists? pretend orphans don't exist
bool exists = (err != LFS_ERR_NOENT);
if (exists && tag != LFSR_TAG_ORPHAN) {
return LFS_ERR_EXIST;
}
// check that name fits
lfs_size_t name_len = lfsr_path_namelen(path);
if (name_len > lfs->name_limit) {
return LFS_ERR_NAMETOOLONG;
}
// find an arbitrary directory-id (did)
//
// This could be anything, but we want to have few collisions while
// also being deterministic. Here we use the checksum of the
// filename xored with the parent's did.
//
// did = parent_did xor crc32c(name)
//
// We use crc32c here not because it is a good hash function, but
// because it is convenient. The did doesn't need to be reproducible
// so this isn't a compatibility concern.
//
// We also truncate to make better use of our leb128 encoding. This is
// somewhat arbitrary, but if we truncate too much we risk increasing
// the number of collisions, so we want to aim for ~2x the number dids
// in the system:
//
// dmask = 2*dids
//
// But we don't actually know how many dids are in the system.
// Fortunately, we can guess an upper bound based on the number of
// mdirs in the mtree:
//
// mdirs
// dmask = 2 * -----
// d
//
// Worst case (or best case?) each directory needs 1 name tag, 1 did
// tag, and 1 bookmark. With our current compaction strategy, each tag
// needs 3t+4 bytes for tag+alts (see our rattr_estimate). And, if
// we assume ~1/2 block utilization due to our mdir split threshold, we
// can multiply everything by 2:
//
// d = 3 * (3t+4) * 2 = 18t + 24
//
// Assuming t=4 bytes, the minimum tag encoding:
//
// d = 18*4 + 24 = 96 bytes
//
// Rounding down to a power-of-two (again this is all arbitrary), gives
// us ~64 bytes per directory:
//
// mdirs mdirs
// dmask = 2 * ----- = -----
// 64 32
//
// This is a nice number because for common NOR flash geometry,
// 4096/32 = 128, so a filesystem with a single mdir encodes dids in a
// single byte.
//
// Note we also need to be careful to catch integer overflow.
//
lfsr_did_t dmask
= (1 << lfs_min(
lfs_nlog2(lfsr_mtree_weight(lfs) >> lfs->mbits)
+ lfs_nlog2(lfs->cfg->block_size/32),
31)
) - 1;
lfsr_did_t did_ = (did ^ lfs_crc32c(0, path, name_len)) & dmask;
// check if we have a collision, if we do, search for the next
// available did
while (true) {
err = lfsr_mtree_namelookup(lfs, did_, NULL, 0,
&mdir, NULL, NULL);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// try the next did
did_ = (did_ + 1) & dmask;
}
// found a good did, now to commit to the mtree
//
// A problem: we need to create both:
// 1. the metadata entry
// 2. the bookmark entry
//
// To do this atomically, we first create the bookmark entry with a grm
// to delete-self in case of powerloss, then create the metadata entry
// while atomically cancelling the grm.
//
// This is done automatically by lfsr_mdir_commit to avoid issues with
// mid updates, since the mid technically doesn't exist yet...
// commit our bookmark and a grm to self-remove in case of powerloss
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
LFSR_RATTR_NAME(
LFSR_TAG_BOOKMARK, +1, did_, NULL, 0),
LFSR_RATTR(
LFSR_TAG_GRMPUSH, 0)));
if (err) {
return err;
}
LFS_ASSERT(lfs->grm.queue[0] == mdir.mid);
// committing our bookmark may have changed the mid of our metadata entry,
// we need to look it up again, we can at least avoid the full path walk
err = lfsr_mtree_namelookup(lfs, did, path, name_len,
&mdir, NULL, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
LFS_ASSERT((exists) ? !err : err == LFS_ERR_NOENT);
// commit our new directory into our parent, zeroing the grm in the
// process
lfsr_grm_pop(lfs);
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
LFSR_RATTR_NAME(
LFSR_TAG_MASK12 | LFSR_TAG_DIR, (!exists) ? +1 : 0,
did, path, name_len),
LFSR_RATTR_LEB128(
LFSR_TAG_DID, 0, did_)));
if (err) {
return err;
}
// update in-device state
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// mark any clobbered uncreats as zombied
if (exists
&& lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid) {
o->flags = (o->flags & ~LFS_o_UNCREAT)
| LFS_o_ZOMBIE
| LFS_o_UNSYNC
| LFS_O_DESYNC;
// update dir positions
} else if (!exists
&& lfsr_o_type(o->flags) == LFS_TYPE_DIR
&& ((lfsr_dir_t*)o)->did == did
&& o->mdir.mid >= mdir.mid) {
((lfsr_dir_t*)o)->pos += 1;
}
}
return 0;
}
// push a did to grm, but only if the directory is empty
static int lfsr_grm_pushdid(lfs_t *lfs, lfsr_did_t did) {
// first lookup the bookmark entry
lfsr_mdir_t bookmark_mdir;
int err = lfsr_mtree_namelookup(lfs, did, NULL, 0,
&bookmark_mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
lfsr_mid_t bookmark_mid = bookmark_mdir.mid;
// check that the directory is empty
bookmark_mdir.mid += 1;
if (lfsr_mrid(lfs, bookmark_mdir.mid)
>= (lfsr_srid_t)bookmark_mdir.rbyd.weight) {
err = lfsr_mtree_lookup(lfs,
lfsr_mbid(lfs, bookmark_mdir.mid-1) + 1,
&bookmark_mdir);
if (err) {
if (err == LFS_ERR_NOENT) {
goto empty;
}
return err;
}
}
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &bookmark_mdir,
LFSR_TAG_MASK8 | LFSR_TAG_NAME,
NULL, &data);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
lfsr_did_t did_;
err = lfsr_data_readleb128(lfs, &data, &did_);
if (err) {
return err;
}
if (did_ == did) {
return LFS_ERR_NOTEMPTY;
}
empty:;
lfsr_grm_push(lfs, bookmark_mid);
return 0;
}
// needed in lfsr_remove
static int lfsr_fs_fixgrm(lfs_t *lfs);
int lfsr_remove(lfs_t *lfs, const char *path) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
// lookup our entry
lfsr_mdir_t mdir;
lfsr_tag_t tag;
lfsr_did_t did;
err = lfsr_mtree_pathlookup(lfs, &path,
&mdir, &tag, &did);
if (err) {
return err;
}
// pretend orphans don't exist
if (tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// trying to remove the root dir?
if (mdir.mid == -1) {
return LFS_ERR_INVAL;
}
// if we're removing a directory, we need to also remove the
// bookmark entry
lfsr_did_t did_ = 0;
if (tag == LFSR_TAG_DIR) {
// first lets figure out the did
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &mdir, LFSR_TAG_DID,
NULL, &data);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, &data, &did_);
if (err) {
return err;
}
// mark bookmark for removal with grm
err = lfsr_grm_pushdid(lfs, did_);
if (err) {
return err;
}
}
// are we removing an opened file?
bool zombie = lfsr_omdir_ismidopen(lfs, mdir.mid, -1);
// remove the metadata entry
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
// create a stickynote if zombied
//
// we use a create+delete here to also clear any rattrs
// and trim the entry size
(zombie)
? LFSR_RATTR_NAME(
LFSR_TAG_MASK12 | LFSR_TAG_STICKYNOTE, 0,
did, path, lfsr_path_namelen(path))
: LFSR_RATTR(
LFSR_TAG_RM, -1)));
if (err) {
return err;
}
// update in-device state
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// mark any clobbered uncreats as zombied
if (zombie
&& lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid) {
o->flags |= LFS_o_UNCREAT
| LFS_o_ZOMBIE
| LFS_o_UNSYNC
| LFS_O_DESYNC;
// mark any removed dirs as zombied
} else if (did_
&& lfsr_o_type(o->flags) == LFS_TYPE_DIR
&& ((lfsr_dir_t*)o)->did == did_) {
o->flags |= LFS_o_ZOMBIE;
// update dir positions
} else if (lfsr_o_type(o->flags) == LFS_TYPE_DIR
&& ((lfsr_dir_t*)o)->did == did
&& o->mdir.mid >= mdir.mid) {
if (lfsr_o_iszombie(o->flags)) {
o->flags &= ~LFS_o_ZOMBIE;
} else {
((lfsr_dir_t*)o)->pos -= 1;
}
// clobber entangled traversals
} else if (lfsr_o_type(o->flags) == LFS_type_TRAVERSAL) {
if (lfsr_o_iszombie(o->flags)) {
o->flags &= ~LFS_o_ZOMBIE;
o->mdir.mid -= 1;
lfsr_traversal_clobber(lfs, (lfsr_traversal_t*)o);
}
}
}
// if we were a directory, we need to clean up, fortunately we can leave
// this up to lfsr_fs_fixgrm
err = lfsr_fs_fixgrm(lfs);
if (err) {
// we did complete the remove, so we shouldn't error here, best
// we can do is log this
LFS_WARN("Failed to clean up grm (%d)", err);
}
return 0;
}
int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
// lookup old entry
lfsr_mdir_t old_mdir;
lfsr_tag_t old_tag;
lfsr_did_t old_did;
err = lfsr_mtree_pathlookup(lfs, &old_path,
&old_mdir, &old_tag, &old_did);
if (err) {
return err;
}
// pretend orphans don't exist
if (old_tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// trying to rename the root?
if (old_mdir.mid == -1) {
return LFS_ERR_INVAL;
}
// lookup new entry
lfsr_mdir_t new_mdir;
lfsr_tag_t new_tag;
lfsr_did_t new_did;
err = lfsr_mtree_pathlookup(lfs, &new_path,
&new_mdir, &new_tag, &new_did);
if (err && !(err == LFS_ERR_NOENT && lfsr_path_islast(new_path))) {
return err;
}
bool exists = (err != LFS_ERR_NOENT);
// there are a few cases we need to watch out for
lfs_size_t new_name_len = lfsr_path_namelen(new_path);
lfsr_did_t new_did_ = 0;
if (!exists) {
// if we're a file, don't allow trailing slashes
if (old_tag != LFSR_TAG_DIR && lfsr_path_isdir(new_path)) {
return LFS_ERR_NOTDIR;
}
// check that name fits
if (new_name_len > lfs->name_limit) {
return LFS_ERR_NAMETOOLONG;
}
} else {
// trying to rename the root?
if (new_mdir.mid == -1) {
return LFS_ERR_INVAL;
}
// we allow reg <-> stickynote renaming, but renaming a non-dir
// to a dir and a dir to a non-dir is an error
if (old_tag != LFSR_TAG_DIR && new_tag == LFSR_TAG_DIR) {
return LFS_ERR_ISDIR;
}
if (old_tag == LFSR_TAG_DIR
&& new_tag != LFSR_TAG_DIR
// pretend orphans don't exist
&& new_tag != LFSR_TAG_ORPHAN) {
return LFS_ERR_NOTDIR;
}
// renaming to ourself is a noop
if (old_mdir.mid == new_mdir.mid) {
return 0;
}
// if our destination is a directory, we will be implicitly removing
// the directory, we need to create a grm for this
if (new_tag == LFSR_TAG_DIR) {
// TODO deduplicate the isempty check with lfsr_remove?
// first lets figure out the did
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &new_mdir, LFSR_TAG_DID,
NULL, &data);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, &data, &new_did_);
if (err) {
return err;
}
// mark bookmark for removal with grm
err = lfsr_grm_pushdid(lfs, new_did_);
if (err) {
return err;
}
}
}
if (old_tag == LFSR_TAG_UNKNOWN) {
// lookup the actual tag
err = lfsr_rbyd_lookup(lfs, &old_mdir.rbyd,
lfsr_mrid(lfs, old_mdir.mid), LFSR_TAG_MASK8 | LFSR_TAG_NAME,
&old_tag, NULL);
if (err) {
return err;
}
}
// mark old entry for removal with a grm
lfsr_grm_push(lfs, old_mdir.mid);
// rename our entry, copying all tags associated with the old rid to the
// new rid, while also marking the old rid for removal
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &new_mdir, LFSR_RATTRS(
LFSR_RATTR_NAME(
LFSR_TAG_MASK12 | old_tag, (!exists) ? +1 : 0,
new_did, new_path, new_name_len),
LFSR_RATTR_MOVE(&old_mdir)));
if (err) {
return err;
}
// update in-device state
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
// mark any clobbered uncreats as zombied
if (exists
&& lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == new_mdir.mid) {
o->flags = (o->flags & ~LFS_o_UNCREAT)
| LFS_o_ZOMBIE
| LFS_o_UNSYNC
| LFS_O_DESYNC;
// update moved files with the new mdir
} else if (lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == lfs->grm.queue[0]) {
o->mdir = new_mdir;
// mark any removed dirs as zombied
} else if (new_did_
&& lfsr_o_type(o->flags) == LFS_TYPE_DIR
&& ((lfsr_dir_t*)o)->did == new_did_) {
o->flags |= LFS_o_ZOMBIE;
// update dir positions
} else if (lfsr_o_type(o->flags) == LFS_TYPE_DIR) {
if (!exists
&& ((lfsr_dir_t*)o)->did == new_did
&& o->mdir.mid >= new_mdir.mid) {
((lfsr_dir_t*)o)->pos += 1;
}
if (((lfsr_dir_t*)o)->did == old_did
&& o->mdir.mid >= lfs->grm.queue[0]) {
if (o->mdir.mid == lfs->grm.queue[0]) {
o->mdir.mid += 1;
} else {
((lfsr_dir_t*)o)->pos -= 1;
}
}
// clobber entangled traversals
} else if (lfsr_o_type(o->flags) == LFS_type_TRAVERSAL
&& ((exists && o->mdir.mid == new_mdir.mid)
|| o->mdir.mid == lfs->grm.queue[0])) {
lfsr_traversal_clobber(lfs, (lfsr_traversal_t*)o);
}
}
// we need to clean up any pending grms, fortunately we can leave
// this up to lfsr_fs_fixgrm
err = lfsr_fs_fixgrm(lfs);
if (err) {
// we did complete the remove, so we shouldn't error here, best
// we can do is log this
LFS_WARN("Failed to clean up grm (%d)", err);
}
return 0;
}
// this just populates the info struct based on what we found
static int lfsr_stat_(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_tag_t tag, lfsr_data_t name,
struct lfs_info *info) {
// get file type from the tag
info->type = lfsr_tag_subtype(tag);
// read the file name
LFS_ASSERT(lfsr_data_size(name) <= LFS_NAME_MAX);
lfs_ssize_t name_len = lfsr_data_read(lfs, &name,
info->name, LFS_NAME_MAX);
if (name_len < 0) {
return name_len;
}
info->name[name_len] = '\0';
// default size to zero
info->size = 0;
// get file size if we're a regular file
if (tag == LFSR_TAG_REG) {
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, mdir,
LFSR_TAG_MASK8 | LFSR_TAG_STRUCT,
&tag, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
// in bshrubs/btrees, size is always the first field
err = lfsr_data_readleb128(lfs, &data, &info->size);
if (err) {
return err;
}
}
}
return 0;
}
int lfsr_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
// lookup our entry
lfsr_mdir_t mdir;
lfsr_tag_t tag;
int err = lfsr_mtree_pathlookup(lfs, &path,
&mdir, &tag, NULL);
if (err) {
return err;
}
// pretend orphans don't exist
if (tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// special case for root
if (mdir.mid == -1) {
lfs_strcpy(info->name, "/");
info->type = LFS_TYPE_DIR;
info->size = 0;
return 0;
}
// fill out our info struct
return lfsr_stat_(lfs, &mdir,
tag, LFSR_DATA_BUF(path, lfsr_path_namelen(path)),
info);
}
// needed in lfsr_dir_open
static int lfsr_dir_rewind_(lfs_t *lfs, lfsr_dir_t *dir);
int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
// already open?
LFS_ASSERT(!lfsr_omdir_isopen(lfs, &dir->o));
// setup dir state
dir->o.flags = lfsr_o_typeflags(LFS_TYPE_DIR);
// lookup our directory
lfsr_mdir_t mdir;
lfsr_tag_t tag;
int err = lfsr_mtree_pathlookup(lfs, &path,
&mdir, &tag, NULL);
if (err) {
return err;
}
// pretend orphans don't exist
if (tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// read our did from the mdir, unless we're root
if (mdir.mid == -1) {
dir->did = 0;
} else {
// not a directory?
if (tag != LFSR_TAG_DIR) {
return LFS_ERR_NOTDIR;
}
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &mdir, LFSR_TAG_DID,
NULL, &data);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, &data, &dir->did);
if (err) {
return err;
}
}
// let rewind initialize the pos state
err = lfsr_dir_rewind_(lfs, dir);
if (err) {
return err;
}
// add to tracked mdirs
lfsr_omdir_open(lfs, &dir->o);
return 0;
}
int lfsr_dir_close(lfs_t *lfs, lfsr_dir_t *dir) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &dir->o));
// remove from tracked mdirs
lfsr_omdir_close(lfs, &dir->o);
return 0;
}
int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &dir->o));
// was our dir removed?
if (lfsr_o_iszombie(dir->o.flags)) {
return LFS_ERR_NOENT;
}
// handle dots specially
if (dir->pos == 0) {
lfs_strcpy(info->name, ".");
info->type = LFS_TYPE_DIR;
info->size = 0;
dir->pos += 1;
return 0;
} else if (dir->pos == 1) {
lfs_strcpy(info->name, "..");
info->type = LFS_TYPE_DIR;
info->size = 0;
dir->pos += 1;
return 0;
}
while (true) {
// next mdir?
if (lfsr_mrid(lfs, dir->o.mdir.mid)
>= (lfsr_srid_t)dir->o.mdir.rbyd.weight) {
int err = lfsr_mtree_lookup(lfs,
lfsr_mbid(lfs, dir->o.mdir.mid-1) + 1,
&dir->o.mdir);
if (err) {
return err;
}
}
// lookup the next name tag
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &dir->o.mdir,
LFSR_TAG_MASK8 | LFSR_TAG_NAME,
&tag, &data);
if (err) {
return err;
}
// get the did
lfsr_did_t did;
err = lfsr_data_readleb128(lfs, &data, &did);
if (err) {
return err;
}
// did mismatch? this terminates the dir read
if (did != dir->did) {
return LFS_ERR_NOENT;
}
// skip orphans, we pretend these don't exist
if (tag == LFSR_TAG_ORPHAN) {
dir->o.mdir.mid += 1;
dir->pos += 1;
continue;
}
// fill out our info struct
err = lfsr_stat_(lfs, &dir->o.mdir, tag, data,
info);
if (err) {
return err;
}
// eagerly set to next entry
dir->o.mdir.mid += 1;
dir->pos += 1;
return 0;
}
}
int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &dir->o));
// do nothing if removed
if (lfsr_o_iszombie(dir->o.flags)) {
return 0;
}
// first rewind
int err = lfsr_dir_rewind_(lfs, dir);
if (err) {
return err;
}
// then seek to the requested offset
//
// note the -2 to adjust for dot entries
lfs_off_t off_ = off - 2;
while (off_ > 0) {
// next mdir?
if (lfsr_mrid(lfs, dir->o.mdir.mid)
>= (lfsr_srid_t)dir->o.mdir.rbyd.weight) {
int err = lfsr_mtree_lookup(lfs,
lfsr_mbid(lfs, dir->o.mdir.mid-1) + 1,
&dir->o.mdir);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
}
lfs_off_t d = lfs_min(
off_,
dir->o.mdir.rbyd.weight
- lfsr_mrid(lfs, dir->o.mdir.mid));
dir->o.mdir.mid += d;
off_ -= d;
}
dir->pos = off;
return 0;
}
lfs_soff_t lfsr_dir_tell(lfs_t *lfs, lfsr_dir_t *dir) {
(void)lfs;
LFS_ASSERT(lfsr_omdir_isopen(lfs, &dir->o));
return dir->pos;
}
static int lfsr_dir_rewind_(lfs_t *lfs, lfsr_dir_t *dir) {
// do nothing if removed
if (lfsr_o_iszombie(dir->o.flags)) {
return 0;
}
// lookup our bookmark in the mtree
int err = lfsr_mtree_namelookup(lfs, dir->did, NULL, 0,
&dir->o.mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// eagerly set to next entry
dir->o.mdir.mid += 1;
// reset pos
dir->pos = 0;
return 0;
}
int lfsr_dir_rewind(lfs_t *lfs, lfsr_dir_t *dir) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &dir->o));
return lfsr_dir_rewind_(lfs, dir);
}
/// Custom attribute stuff ///
static int lfsr_lookupattr(lfs_t *lfs, const char *path, uint8_t type,
lfsr_mdir_t *mdir_, lfsr_data_t *data_) {
// lookup our entry
lfsr_tag_t tag;
int err = lfsr_mtree_pathlookup(lfs, &path,
mdir_, &tag, NULL);
if (err) {
return err;
}
// pretend orphans don't exist
if (tag == LFSR_TAG_ORPHAN) {
return LFS_ERR_NOENT;
}
// lookup our attr
err = lfsr_mdir_lookup(lfs, mdir_, LFSR_TAG_ATTR(type),
NULL, data_);
if (err) {
if (err == LFS_ERR_NOENT) {
return LFS_ERR_NOATTR;
}
return err;
}
return 0;
}
lfs_ssize_t lfsr_getattr(lfs_t *lfs, const char *path, uint8_t type,
void *buffer, lfs_size_t size) {
// lookup our attr
lfsr_mdir_t mdir;
lfsr_data_t data;
int err = lfsr_lookupattr(lfs, path, type,
&mdir, &data);
if (err) {
return err;
}
// read the attr
return lfsr_data_read(lfs, &data, buffer, size);
}
lfs_ssize_t lfsr_sizeattr(lfs_t *lfs, const char *path, uint8_t type) {
// lookup our attr
lfsr_mdir_t mdir;
lfsr_data_t data;
int err = lfsr_lookupattr(lfs, path, type,
&mdir, &data);
if (err) {
return err;
}
// return the attr size
return lfsr_data_size(data);
}
int lfsr_setattr(lfs_t *lfs, const char *path, uint8_t type,
const void *buffer, lfs_size_t size) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
// lookup our attr
lfsr_mdir_t mdir;
lfsr_data_t data;
err = lfsr_lookupattr(lfs, path, type,
&mdir, &data);
if (err && err != LFS_ERR_NOATTR) {
return err;
}
// commit our attr
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
LFSR_RATTR_BUF(
LFSR_TAG_ATTR(type), 0,
buffer, size)));
if (err) {
return err;
}
// update any opened files tracking custom attrs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (!(lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid
&& !lfsr_o_isdesync(o->flags))) {
continue;
}
lfsr_file_t *file = (lfsr_file_t*)o;
for (lfs_size_t i = 0; i < file->cfg->attr_count; i++) {
if (!(file->cfg->attrs[i].type == type
&& !lfsr_o_iswronly(file->cfg->attrs[i].flags))) {
continue;
}
lfs_size_t d = lfs_min(size, file->cfg->attrs[i].buffer_size);
lfs_memcpy(file->cfg->attrs[i].buffer, buffer, d);
if (file->cfg->attrs[i].size) {
*file->cfg->attrs[i].size = d;
}
}
}
return 0;
}
int lfsr_removeattr(lfs_t *lfs, const char *path, uint8_t type) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
// lookup our attr
lfsr_mdir_t mdir;
err = lfsr_lookupattr(lfs, path, type,
&mdir, NULL);
if (err) {
return err;
}
// commit our removal
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
LFSR_RATTR(
LFSR_TAG_RM | LFSR_TAG_ATTR(type), 0)));
if (err) {
return err;
}
// update any opened files tracking custom attrs
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (!(lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == mdir.mid
&& !lfsr_o_isdesync(o->flags))) {
continue;
}
lfsr_file_t *file = (lfsr_file_t*)o;
for (lfs_size_t i = 0; i < file->cfg->attr_count; i++) {
if (!(file->cfg->attrs[i].type == type
&& !lfsr_o_iswronly(file->cfg->attrs[i].flags))) {
continue;
}
if (file->cfg->attrs[i].size) {
*file->cfg->attrs[i].size = LFS_ERR_NOATTR;
}
}
}
return 0;
}
/// File operations ///
// file helpers
static inline void lfsr_file_discardcache(lfsr_file_t *file) {
file->b.o.flags &= ~LFS_o_UNFLUSH;
file->cache.pos = 0;
file->cache.size = 0;
}
static inline void lfsr_file_discardleaf(lfsr_file_t *file) {
file->b.o.flags &= ~LFS_o_UNCRYST & ~LFS_o_UNGRAFT;
file->leaf.pos = 0;
file->leaf.weight = 0;
lfsr_bptr_discard(&file->leaf.bptr);
}
static inline void lfsr_file_discardbshrub(lfsr_file_t *file) {
lfsr_bshrub_init(&file->b);
}
static inline lfs_size_t lfsr_file_cachesize(lfs_t *lfs,
const lfsr_file_t *file) {
return (file->cfg->cache_size)
? file->cfg->cache_size
: lfs->cfg->file_cache_size;
}
static inline lfs_off_t lfsr_file_weight(const lfsr_file_t *file) {
return lfs_max(
file->leaf.pos + file->leaf.weight,
file->b.shrub.weight);
}
static inline lfs_off_t lfsr_file_size_(const lfsr_file_t *file) {
return lfs_max(
file->cache.pos + file->cache.size,
lfsr_file_weight(file));
}
// file operations
static int lfsr_file_fetch(lfs_t *lfs, lfsr_file_t *file, bool trunc) {
// default data state
lfsr_file_discardbshrub(file);
// discard the current cache
lfsr_file_discardcache(file);
// discard the current leaf
lfsr_file_discardleaf(file);
// don't bother reading disk if we're not created or truncating
if (!lfsr_o_isuncreat(file->b.o.flags) && !trunc) {
// lookup the file struct, if there is one
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &file->b.o.mdir,
LFSR_TAG_MASK8 | LFSR_TAG_DATA,
&tag, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// note many of these functions leave bshrub undefined if there
// is an error, so we first read into the staging bshrub
file->b.shrub_ = file->b.shrub;
// found a bshrub/btree?
if (err != LFS_ERR_NOENT) {
// may be a bshrub (inlined btree)
if (tag == LFSR_TAG_BSHRUB) {
err = lfsr_data_readshrub(lfs, &data, &file->b.o.mdir,
&file->b.shrub_);
if (err) {
return err;
}
// or a btree
} else if (tag == LFSR_TAG_BTREE) {
err = lfsr_data_fetchbtree(lfs, &data,
&file->b.shrub_);
if (err) {
return err;
}
} else {
LFS_UNREACHABLE();
}
}
// update the bshrub/btree
file->b.shrub = file->b.shrub_;
// mark as in-sync
file->b.o.flags &= ~LFS_o_UNSYNC;
}
// try to fetch any custom attributes
for (lfs_size_t i = 0; i < file->cfg->attr_count; i++) {
// skip writeonly attrs
if (lfsr_o_iswronly(file->cfg->attrs[i].flags)) {
continue;
}
// don't bother reading disk if we're not created yet
if (lfsr_o_isuncreat(file->b.o.flags)) {
if (file->cfg->attrs[i].size) {
*file->cfg->attrs[i].size = LFS_ERR_NOATTR;
}
continue;
}
// lookup the attr
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &file->b.o.mdir,
LFSR_TAG_ATTR(file->cfg->attrs[i].type),
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// read the attr, if it exists
if (err == LFS_ERR_NOENT
// awkward case here if buffer_size is LFS_ERR_NOATTR
|| file->cfg->attrs[i].buffer_size == LFS_ERR_NOATTR) {
if (file->cfg->attrs[i].size) {
*file->cfg->attrs[i].size = LFS_ERR_NOATTR;
}
} else {
lfs_ssize_t d = lfsr_data_read(lfs, &data,
file->cfg->attrs[i].buffer,
file->cfg->attrs[i].buffer_size);
if (d < 0) {
return d;
}
if (file->cfg->attrs[i].size) {
*file->cfg->attrs[i].size = d;
}
}
}
return 0;
}
// needed in lfsr_file_opencfg
static void lfsr_file_close_(lfs_t *lfs, const lfsr_file_t *file);
static int lfsr_file_ck(lfs_t *lfs, const lfsr_file_t *file,
uint32_t flags);
int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
const char *path, uint32_t flags,
const struct lfs_file_config *cfg) {
// already open?
LFS_ASSERT(!lfsr_omdir_isopen(lfs, &file->b.o));
// don't allow the forbidden mode!
LFS_ASSERT((flags & 3) != 3);
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_O_RDONLY
| LFS_O_WRONLY
| LFS_O_RDWR
| LFS_O_CREAT
| LFS_O_EXCL
| LFS_O_TRUNC
| LFS_O_APPEND
| LFS_O_FLUSH
| LFS_O_SYNC
| LFS_O_DESYNC
| LFS_O_CKMETA
| LFS_O_CKDATA)) == 0);
// writeable files require a writeable filesystem
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags) || lfsr_o_isrdonly(flags));
// these flags require a writable file
LFS_ASSERT(!lfsr_o_isrdonly(flags) || !lfsr_o_iscreat(flags));
LFS_ASSERT(!lfsr_o_isrdonly(flags) || !lfsr_o_isexcl(flags));
LFS_ASSERT(!lfsr_o_isrdonly(flags) || !lfsr_o_istrunc(flags));
for (lfs_size_t i = 0; i < cfg->attr_count; i++) {
// these flags require a writable attr
LFS_ASSERT(!lfsr_o_isrdonly(cfg->attrs[i].flags)
|| !lfsr_o_iscreat(cfg->attrs[i].flags));
LFS_ASSERT(!lfsr_o_isrdonly(cfg->attrs[i].flags)
|| !lfsr_o_isexcl(cfg->attrs[i].flags));
}
// mounted with LFS_M_FLUSH/SYNC? implies LFS_O_FLUSH/SYNC
flags |= lfs->flags & (LFS_M_FLUSH | LFS_M_SYNC);
if (!lfsr_o_isrdonly(flags)) {
// prepare our filesystem for writing
int err = lfsr_fs_mkconsistent(lfs);
if (err) {
return err;
}
}
// setup file state
file->cfg = cfg;
file->b.o.flags = flags
| lfsr_o_typeflags(LFS_TYPE_REG)
// default to unsynced for uncreated/truncated files
| LFS_o_UNSYNC;
file->pos = 0;
// lookup our parent
lfsr_tag_t tag;
lfsr_did_t did;
int err = lfsr_mtree_pathlookup(lfs, &path,
&file->b.o.mdir, &tag, &did);
if (err && !(err == LFS_ERR_NOENT && lfsr_path_islast(path))) {
return err;
}
bool exists = err != LFS_ERR_NOENT;
// creating a new entry?
if (!exists || tag == LFSR_TAG_ORPHAN) {
if (!lfsr_o_iscreat(flags)) {
return LFS_ERR_NOENT;
}
LFS_ASSERT(!lfsr_o_isrdonly(flags));
// we're a file, don't allow trailing slashes
if (lfsr_path_isdir(path)) {
return LFS_ERR_NOTDIR;
}
// create a stickynote entry if we don't have one, this reserves the
// mid until first sync
if (!exists) {
// check that name fits
lfs_size_t name_len = lfsr_path_namelen(path);
if (name_len > lfs->name_limit) {
return LFS_ERR_NAMETOOLONG;
}
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, &file->b.o.mdir, LFSR_RATTRS(
LFSR_RATTR_NAME(
LFSR_TAG_STICKYNOTE, +1,
did, path, name_len)));
if (err) {
return err;
}
// update dir positions
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_type(o->flags) == LFS_TYPE_DIR
&& ((lfsr_dir_t*)o)->did == did
&& o->mdir.mid >= file->b.o.mdir.mid) {
((lfsr_dir_t*)o)->pos += 1;
}
}
}
} else {
// wanted to create a new entry?
if (lfsr_o_isexcl(flags)) {
return LFS_ERR_EXIST;
}
// wrong type?
if (tag == LFSR_TAG_DIR) {
return LFS_ERR_ISDIR;
}
if (tag == LFSR_TAG_UNKNOWN) {
return LFS_ERR_NOTSUP;
}
}
// if stickynote, mark as uncreated, we need to convert to reg file
// on first sync
if (!exists
|| tag == LFSR_TAG_STICKYNOTE
|| tag == LFSR_TAG_ORPHAN) {
file->b.o.flags |= LFS_o_UNCREAT;
}
// allocate cache if necessary
if (file->cfg->cache_buffer) {
file->cache.buffer = file->cfg->cache_buffer;
} else {
file->cache.buffer = lfs_malloc(lfsr_file_cachesize(lfs, file));
if (!file->cache.buffer) {
return LFS_ERR_NOMEM;
}
}
// fetch the file struct and custom attrs
err = lfsr_file_fetch(lfs, file, lfsr_o_istrunc(flags));
if (err) {
goto failed;
}
// check metadata/data for errors?
if (lfsr_t_isckmeta(flags) || lfsr_t_isckdata(flags)) {
err = lfsr_file_ck(lfs, file, flags);
if (err) {
goto failed;
}
}
// add to tracked mdirs
lfsr_omdir_open(lfs, &file->b.o);
return 0;
failed:;
// clean up resources
lfsr_file_close_(lfs, file);
return err;
}
// default file config
static const struct lfs_file_config lfsr_file_defaults = {0};
int lfsr_file_open(lfs_t *lfs, lfsr_file_t *file,
const char *path, uint32_t flags) {
return lfsr_file_opencfg(lfs, file, path, flags, &lfsr_file_defaults);
}
// clean up resources
static void lfsr_file_close_(lfs_t *lfs, const lfsr_file_t *file) {
// clean up memory
if (!file->cfg->cache_buffer) {
lfs_free(file->cache.buffer);
}
// are we orphaning a file?
//
// make sure we check _after_ removing ourselves
if (lfsr_o_isuncreat(file->b.o.flags)
&& !lfsr_omdir_ismidopen(lfs, file->b.o.mdir.mid, -1)) {
// this gets a bit messy, since we're not able to write to the
// filesystem if we're rdonly or desynced, fortunately we have
// a few tricks
// first try to push onto our grm queue
if (lfsr_grm_count(lfs) < 2) {
lfsr_grm_push(lfs, file->b.o.mdir.mid);
// fallback to just marking the filesystem as inconsistent
} else {
lfs->flags |= LFS_I_MKCONSISTENT;
}
}
}
// needed in lfsr_file_close
int lfsr_file_sync(lfs_t *lfs, lfsr_file_t *file);
int lfsr_file_close(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// don't call lfsr_file_sync if we're readonly or desynced
int err = 0;
if (!lfsr_o_isrdonly(file->b.o.flags)
&& !lfsr_o_isdesync(file->b.o.flags)) {
err = lfsr_file_sync(lfs, file);
}
// remove from tracked mdirs
lfsr_omdir_close(lfs, &file->b.o);
// clean up resources
lfsr_file_close_(lfs, file);
return err;
}
// low-level file reading
static int lfsr_file_lookup_(lfs_t *lfs, const lfsr_file_t *file,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_bid_t *weight_, lfsr_bptr_t *bptr_) {
lfsr_tag_t tag;
lfsr_bid_t weight;
lfsr_data_t data;
int err = lfsr_bshrub_lookupnext(lfs, &file->b, bid,
bid_, &tag, &weight, &data);
if (err) {
return err;
}
LFS_ASSERT(tag == LFSR_TAG_DATA
|| tag == LFSR_TAG_BLOCK);
// decode bptrs
if (tag == LFSR_TAG_DATA) {
bptr_->data = data;
} else {
err = lfsr_data_readbptr(lfs, &data, bptr_);
if (err) {
return err;
}
}
// limit bptrs to btree weights, this may be useful for
// compression in the future
bptr_->data = LFSR_DATA_TRUNCATE(bptr_->data, weight);
if (weight_) {
*weight_ = weight;
}
return 0;
}
static int lfsr_file_lookup(lfs_t *lfs, const lfsr_file_t *file,
lfsr_bid_t bid,
lfsr_bid_t *bid_, lfsr_bid_t *weight_, lfsr_bptr_t *bptr_) {
// hits our leaf?
if (bid >= file->leaf.pos
&& bid < file->leaf.pos + file->leaf.weight) {
if (bid_) {
*bid_ = file->leaf.pos + (file->leaf.weight-1);
}
if (weight_) {
*weight_ = file->leaf.weight;
}
*bptr_ = file->leaf.bptr;
return 0;
}
// in between bshrub/btree and ungrafted leaf? pretend there's a
// hole here
if (bid >= file->b.shrub.weight && bid < file->leaf.pos) {
if (bid_) {
*bid_ = file->leaf.pos-1;
}
if (weight_) {
*weight_ = file->leaf.pos - file->b.shrub.weight;
}
lfsr_bptr_discard(bptr_);
return 0;
}
// lookup on disk
lfsr_bid_t bid__;
lfsr_bid_t weight__;
int err = lfsr_file_lookup_(lfs, file, bid,
&bid__, &weight__, bptr_);
if (err) {
return err;
}
// hits our leaf? our leaf takes priority
//
// slice left leaf?
if (bid > file->leaf.pos + file->leaf.weight
&& bid__-(weight__-1) < file->leaf.pos + file->leaf.weight) {
lfs_soff_t d = (file->leaf.pos + file->leaf.weight)
- (bid__-(weight__-1));
weight__ -= d;
bptr_->data = LFSR_DATA_SLICE(bptr_->data,
lfs_min(d, lfsr_bptr_size(bptr_)),
-1);
// slice right leaf?
} else if (bid < file->leaf.pos
&& bid__+1 > file->leaf.pos) {
lfs_soff_t d = bid__+1 - file->leaf.pos;
bid__ -= d;
weight__ -= d;
bptr_->data = LFSR_DATA_SLICE(bptr_->data,
-1,
lfsr_bptr_size(bptr_) - lfs_min(d, lfsr_bptr_size(bptr_)));
}
if (bid_) {
*bid_ = bid__;
}
if (weight_) {
*weight_ = weight__;
}
return 0;
}
// needed in lfsr_file_read_
static int lfsr_file_crystallize(lfs_t *lfs, lfsr_file_t *file);
static lfs_ssize_t lfsr_file_read_(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t pos, uint8_t *buffer, lfs_size_t size) {
// need to fetch a new leaf?
if (!(pos >= file->leaf.pos
&& pos < file->leaf.pos + file->leaf.weight)) {
// leaf in use? we need to crystallize/graft it
//
// it would be easier to just call lfsr_file_flush here, but
// we don't want to drag in the extra stack usage
if (lfsr_o_isungraft(file->b.o.flags)
|| lfsr_o_isuncryst(file->b.o.flags)) {
int err = lfsr_file_crystallize(lfs, file);
if (err) {
return err;
}
}
// fetch a leaf
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup_(lfs, file, pos,
&bid, &weight, &bptr);
if (err) {
return err;
}
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)
&& lfsr_bptr_isbptr(&bptr)) {
err = lfsr_bptr_ck(lfs, &bptr);
if (err) {
return err;
}
}
#endif
file->leaf.pos = bid - (weight-1);
file->leaf.weight = weight;
file->leaf.bptr = bptr;
}
// any data on disk?
lfs_off_t pos_ = pos;
if (pos_ < file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr)) {
// note one important side-effect here is a strict
// data hint
lfs_ssize_t d = lfs_min(
size,
lfsr_bptr_size(&file->leaf.bptr)
- (pos_ - file->leaf.pos));
lfsr_data_t slice = LFSR_DATA_SLICE(file->leaf.bptr.data,
pos_ - file->leaf.pos,
d);
d = lfsr_data_read(lfs, &slice,
buffer, d);
if (d < 0) {
return d;
}
pos_ += d;
buffer += d;
size -= d;
}
// found a hole? fill with zeros
lfs_ssize_t d = lfs_min(
size,
file->leaf.pos+file->leaf.weight - pos_);
lfs_memset(buffer, 0, d);
pos_ += d;
buffer += d;
size -= d;
return pos_ - pos;
}
// high-level file reading
lfs_ssize_t lfsr_file_read(lfs_t *lfs, lfsr_file_t *file,
void *buffer, lfs_size_t size) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't read from writeonly files
LFS_ASSERT(!lfsr_o_iswronly(file->b.o.flags));
LFS_ASSERT(file->pos + size <= 0x7fffffff);
lfs_off_t pos_ = file->pos;
uint8_t *buffer_ = buffer;
while (size > 0 && pos_ < lfsr_file_size_(file)) {
// keep track of the next highest priority data offset
lfs_ssize_t d = lfs_min(size, lfsr_file_size_(file) - pos_);
// any data in our cache?
if (pos_ < file->cache.pos + file->cache.size
&& file->cache.size != 0) {
if (pos_ >= file->cache.pos) {
lfs_ssize_t d_ = lfs_min(
d,
file->cache.size - (pos_ - file->cache.pos));
lfs_memcpy(buffer_,
&file->cache.buffer[pos_ - file->cache.pos],
d_);
pos_ += d_;
buffer_ += d_;
size -= d_;
d -= d_;
continue;
}
// cached data takes priority
d = lfs_min(d, file->cache.pos - pos_);
}
// any data in our btree?
if (pos_ < lfsr_file_weight(file)) {
// bypass cache?
if ((lfs_size_t)d >= lfsr_file_cachesize(lfs, file)) {
lfs_ssize_t d_ = lfsr_file_read_(lfs, file,
pos_, buffer_, d);
if (d_ < 0) {
LFS_ASSERT(d_ != LFS_ERR_NOENT);
return d_;
}
pos_ += d_;
buffer_ += d_;
size -= d_;
continue;
}
// cache in use? we need to flush it
//
// note that flush does not change the actual file data, so if
// a read fails it's ok to fall back to our flushed state
//
if (lfsr_o_isunflush(file->b.o.flags)) {
int err = lfsr_file_flush(lfs, file);
if (err) {
return err;
}
lfsr_file_discardcache(file);
}
// try to fill our cache with some data
lfs_ssize_t d_ = lfsr_file_read_(lfs, file,
pos_, file->cache.buffer, d);
if (d_ < 0) {
LFS_ASSERT(d != LFS_ERR_NOENT);
return d_;
}
file->cache.pos = pos_;
file->cache.size = d_;
continue;
}
// found a hole? fill with zeros
lfs_memset(buffer_, 0, d);
pos_ += d;
buffer_ += d;
size -= d;
}
// update file and return amount read
lfs_size_t read = pos_ - file->pos;
file->pos = pos_;
return read;
}
// low-level file writing
static int lfsr_file_commit(lfs_t *lfs, lfsr_file_t *file,
lfsr_bid_t bid, const lfsr_rattr_t *rattrs, lfs_size_t rattr_count) {
return lfsr_bshrub_commit(lfs, &file->b,
bid, rattrs, rattr_count);
}
// graft bptr/fragments into our bshrub/btree
static int lfsr_file_graft(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t pos, lfs_off_t weight, lfs_soff_t delta,
// data_count=-1 => single bptr
// data_count>=0 => list of concatenated fragments
const lfsr_data_t *datas, lfs_ssize_t data_count) {
// note! we must never allow our btree size to overflow, even
// temporarily
// can't carve more than the graft weight
LFS_ASSERT(delta >= -(lfs_soff_t)weight);
// carving the entire tree? revert to no bshrub/btree
if (pos == 0
&& weight >= file->b.shrub.weight
&& delta == -(lfs_soff_t)weight) {
lfsr_file_discardbshrub(file);
return 0;
}
// try to merge commits where possible
lfsr_bid_t bid = file->b.shrub.weight;
lfsr_rattr_t rattrs[3];
lfs_size_t rattr_count = 0;
lfsr_bptr_t l;
lfsr_bptr_t r;
// need a hole?
if (pos > file->b.shrub.weight) {
// can we coalesce?
if (file->b.shrub.weight > 0) {
bid = lfs_min(bid, file->b.shrub.weight-1);
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_GROW, +(pos - file->b.shrub.weight));
// new hole
} else {
bid = lfs_min(bid, file->b.shrub.weight);
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_DATA, +(pos - file->b.shrub.weight));
}
}
// try to carve any existing data
lfsr_rattr_t r_rattr_ = {.tag=0};
while (pos < file->b.shrub.weight) {
lfsr_bid_t weight_;
lfsr_bptr_t bptr_;
int err = lfsr_file_lookup_(lfs, file, pos,
&bid, &weight_, &bptr_);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)
&& lfsr_bptr_isbptr(&bptr_)) {
err = lfsr_bptr_ck(lfs, &bptr_);
if (err) {
return err;
}
}
#endif
// note, an entry can be both a left and right sibling
l = bptr_;
l.data = LFSR_DATA_SLICE(bptr_.data,
-1,
pos - (bid-(weight_-1)));
r = bptr_;
r.data = LFSR_DATA_SLICE(bptr_.data,
pos+weight - (bid-(weight_-1)),
-1);
// left sibling needs carving but falls underneath our
// fragment threshold? break into fragments
while (lfsr_bptr_isbptr(&bptr_)
&& lfsr_bptr_size(&l) > lfs->cfg->fragment_size
&& lfsr_bptr_size(&l) < lfs_min(
lfs->cfg->fragment_thresh,
lfs->cfg->crystal_thresh)) {
bptr_.data = LFSR_DATA_SLICE(bptr_.data,
lfs->cfg->fragment_size,
-1);
err = lfsr_file_commit(lfs, file, bid, LFSR_RATTRS(
LFSR_RATTR_DATA(
LFSR_TAG_GROW | LFSR_TAG_MASK8 | LFSR_TAG_DATA,
-(weight_ - lfs->cfg->fragment_size),
&LFSR_DATA_TRUNCATE(l.data,
lfs->cfg->fragment_size)),
LFSR_RATTR_BPTR(
LFSR_TAG_BLOCK,
+(weight_ - lfs->cfg->fragment_size),
&bptr_)));
if (err) {
return err;
}
weight_ -= lfs->cfg->fragment_size;
l.data = LFSR_DATA_SLICE(bptr_.data,
-1,
pos - (bid-(weight_-1)));
}
// right sibling needs carving but falls underneath our
// fragment threshold? break into fragments
while (lfsr_bptr_isbptr(&bptr_)
&& lfsr_bptr_size(&r) > lfs->cfg->fragment_size
&& lfsr_bptr_size(&r) < lfs_min(
lfs->cfg->fragment_thresh,
lfs->cfg->crystal_thresh)) {
bptr_.data = LFSR_DATA_SLICE(bptr_.data,
-1,
lfsr_bptr_size(&bptr_) - lfs->cfg->fragment_size);
err = lfsr_file_commit(lfs, file, bid, LFSR_RATTRS(
LFSR_RATTR_BPTR(
LFSR_TAG_GROW | LFSR_TAG_MASK8 | LFSR_TAG_BLOCK,
-(weight_ - lfsr_bptr_size(&bptr_)),
&bptr_),
LFSR_RATTR_DATA(
LFSR_TAG_DATA,
+(weight_ - lfsr_bptr_size(&bptr_)),
&LFSR_DATA_FRUNCATE(r.data,
lfs->cfg->fragment_size))));
if (err) {
return err;
}
bid -= (weight_-lfsr_bptr_size(&bptr_));
weight_ -= (weight_-lfsr_bptr_size(&bptr_));
r.data = LFSR_DATA_SLICE(bptr_.data,
pos+weight - (bid-(weight_-1)),
-1);
}
// found left sibling?
if (bid-(weight_-1) < pos) {
// can we get away with a grow attribute?
if (lfsr_bptr_size(&bptr_) == lfsr_bptr_size(&l)) {
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_GROW, -(bid+1 - pos));
// carve fragment?
} else if (!lfsr_bptr_isbptr(&bptr_)
|| lfsr_bptr_size(&l) <= lfs->cfg->fragment_size) {
rattrs[rattr_count++] = LFSR_RATTR_DATA(
LFSR_TAG_GROW | LFSR_TAG_MASK8 | LFSR_TAG_DATA,
-(bid+1 - pos),
&l.data);
// carve bptr?
} else {
rattrs[rattr_count++] = LFSR_RATTR_BPTR(
LFSR_TAG_GROW | LFSR_TAG_MASK8 | LFSR_TAG_BLOCK,
-(bid+1 - pos),
&l);
}
// completely overwriting this entry?
} else {
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_RM, -weight_);
}
// spans more than one entry? we can't do everything in one
// commit because it might span more than one btree leaf, so
// commit what we have and move on to next entry
if (pos+weight > bid+1) {
LFS_ASSERT(lfsr_bptr_size(&r) == 0);
LFS_ASSERT(rattr_count <= sizeof(rattrs)/sizeof(lfsr_rattr_t));
err = lfsr_file_commit(lfs, file, bid,
rattrs, rattr_count);
if (err) {
return err;
}
delta += lfs_min(weight, bid+1 - pos);
weight -= lfs_min(weight, bid+1 - pos);
rattr_count = 0;
continue;
}
// found right sibling?
if (pos+weight < bid+1) {
// can we coalesce a hole?
if (lfsr_bptr_size(&r) == 0) {
delta += bid+1 - (pos+weight);
// carve fragment?
} else if (!lfsr_bptr_isbptr(&bptr_)
|| lfsr_bptr_size(&r) <= lfs->cfg->fragment_size) {
r_rattr_ = LFSR_RATTR_DATA(
LFSR_TAG_DATA, bid+1 - (pos+weight),
&r.data);
// carve bptr?
} else {
r_rattr_ = LFSR_RATTR_BPTR(
LFSR_TAG_BLOCK, bid+1 - (pos+weight),
&r);
}
}
delta += lfs_min(weight, bid+1 - pos);
weight -= lfs_min(weight, bid+1 - pos);
break;
}
// append our data
if (weight + delta > 0) {
lfs_size_t dsize = 0;
for (lfs_size_t i = 0;
i < ((data_count < 0) ? 1 : (lfs_size_t)data_count);
i++) {
dsize += lfsr_data_size(datas[i]);
}
// can we coalesce a hole?
if (dsize == 0 && pos > 0) {
bid = lfs_min(bid, file->b.shrub.weight-1);
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_GROW, +(weight + delta));
// need a new hole?
} else if (dsize == 0) {
bid = lfs_min(bid, file->b.shrub.weight);
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_DATA, +(weight + delta));
// append a new fragment?
} else if (data_count >= 0) {
bid = lfs_min(bid, file->b.shrub.weight);
rattrs[rattr_count++] = LFSR_RATTR_CAT_(
LFSR_TAG_DATA, +(weight + delta),
datas, data_count);
// append a new bptr?
} else {
bid = lfs_min(bid, file->b.shrub.weight);
rattrs[rattr_count++] = LFSR_RATTR_BPTR(
LFSR_TAG_BLOCK, +(weight + delta),
(const lfsr_bptr_t*)datas);
}
}
// and don't forget the right sibling
if (r_rattr_.tag) {
rattrs[rattr_count++] = r_rattr_;
}
// commit pending rattrs
if (rattr_count > 0) {
LFS_ASSERT(rattr_count <= sizeof(rattrs)/sizeof(lfsr_rattr_t));
int err = lfsr_file_commit(lfs, file, bid,
rattrs, rattr_count);
if (err) {
return err;
}
}
return 0;
}
static int lfsr_file_crystallize_(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t block_pos, lfs_soff_t crystal_min, lfs_soff_t crystal_max,
lfs_off_t pos, const uint8_t *buffer, lfs_size_t size) {
// align to prog_size, limit to block_size and theoretical file size
lfs_off_t crystal_limit = lfs_min(
block_pos + lfs_min(
lfs_aligndown(
(lfs_off_t)crystal_max,
lfs->cfg->prog_size),
lfs->cfg->block_size),
lfs_max(
pos + size,
lfsr_file_weight(file)));
// do we need to allocate a new block?
if (!lfsr_bptr_isbptr(&file->leaf.bptr)
|| !lfsr_bptr_iserased(&file->leaf.bptr)) {
goto relocate;
}
// if we're resuming crystallization, block pointer shouldn't be
// truncated or anything
LFS_ASSERT(file->leaf.pos - lfsr_bptr_off(&file->leaf.bptr)
== block_pos);
LFS_ASSERT(lfsr_bptr_off(&file->leaf.bptr)
+ lfsr_bptr_size(&file->leaf.bptr)
== lfsr_bptr_cksize(&file->leaf.bptr));
LFS_ASSERT(lfsr_bptr_size(&file->leaf.bptr)
== file->leaf.weight);
// before we write, claim the erased state!
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o != &file->b.o
&& lfsr_bptr_block(&((lfsr_file_t*)o)->leaf.bptr)
== lfsr_bptr_block(&file->leaf.bptr)) {
lfsr_bptr_claim(&((lfsr_file_t*)o)->leaf.bptr);
}
}
// create a temporary copy in case an error happens
lfsr_bptr_t bptr = file->leaf.bptr;
while (true) {
// crystallize data into our block
//
// i.e. eagerly merge any right neighbors unless that would put
// us over our crystal_size/block_size
lfs_off_t pos_ = block_pos
+ lfsr_bptr_off(&bptr)
+ lfsr_bptr_size(&bptr);
uint32_t cksum_ = lfsr_bptr_cksum(&bptr);
while (pos_ < crystal_limit) {
// keep track of the next highest priority data offset
lfs_ssize_t d = crystal_limit - pos_;
// any data in our buffer?
if (pos_ < pos + size && size > 0) {
if (pos_ >= pos) {
lfs_ssize_t d_ = lfs_min(
d,
size - (pos_ - pos));
int err = lfsr_bd_prog(lfs, lfsr_bptr_block(&bptr),
pos_ - block_pos,
&buffer[pos_ - pos], d_,
&cksum_, true);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
pos_ += d_;
d -= d_;
}
// buffered data takes priority
d = lfs_min(d, pos - pos_);
}
// any data on disk?
if (pos_ < lfsr_file_weight(file)) {
lfsr_bid_t bid__;
lfsr_bid_t weight__;
lfsr_bptr_t bptr__;
int err = lfsr_file_lookup(lfs, file, pos_,
&bid__, &weight__, &bptr__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)
&& lfsr_bptr_isbptr(&bptr__)) {
err = lfsr_bptr_ck(lfs, &bptr__);
if (err) {
return err;
}
}
#endif
// is this data a pure hole? stop early to (FUTURE)
// better leverage erased-state in sparse files, and to
// try to avoid writing a bunch of unnecessary zeros
if ((pos_ >= bid__-(weight__-1) + lfsr_bptr_size(&bptr__)
// does this data exceed our block_size? also
// stop early to try to avoid messing up
// block alignment
|| (bid__-(weight__-1) + lfsr_bptr_size(&bptr__))
- block_pos
> lfs->cfg->block_size)
// but make sure to include all of the requested
// crystal if explicit, otherwise above loops
// may never terminate
&& (lfs_soff_t)(pos_ - block_pos) >= crystal_min) {
break;
}
if (pos_ < bid__-(weight__-1) + lfsr_bptr_size(&bptr__)) {
// note one important side-effect here is a strict
// data hint
lfs_ssize_t d_ = lfs_min(
d,
(bid__-(weight__-1) + lfsr_bptr_size(&bptr__))
- pos_);
err = lfsr_bd_progdata(lfs, lfsr_bptr_block(&bptr),
pos_ - block_pos,
LFSR_DATA_SLICE(bptr__.data,
pos_ - (bid__-(weight__-1)),
d_),
&cksum_, true);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
pos_ += d_;
d -= d_;
}
// found a hole? just make sure next leaf takes priority
d = lfs_min(d, bid__+1 - pos_);
}
// found a hole? fill with zeros
int err = lfsr_bd_set(lfs, lfsr_bptr_block(&bptr),
pos_ - block_pos,
0, d,
&cksum_, true);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
pos_ += d;
}
// a bit of a hack here, we need to truncate our block to
// prog_size alignment to avoid padding issues
//
// doing this retroactively to the pcache greatly simplifies the
// above loop, though we may end up reading more than is
// strictly necessary
lfs_ssize_t d = (pos_ - block_pos) % lfs->cfg->prog_size;
lfs->pcache.size -= d;
pos_ -= d;
// finalize our write
int err = lfsr_bd_flush(lfs,
&cksum_, true);
if (err) {
// bad prog? try another block
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// update our block pointer
LFS_ASSERT(pos_ - block_pos >= lfsr_bptr_off(&bptr));
LFS_ASSERT(pos_ - block_pos <= lfs->cfg->block_size);
file->leaf.pos = block_pos + lfsr_bptr_off(&bptr);
file->leaf.weight = pos_ - (block_pos + lfsr_bptr_off(&bptr));
lfsr_bptr_init(&file->leaf.bptr,
LFSR_DATA_DISK(
lfsr_bptr_block(&bptr),
lfsr_bptr_off(&bptr),
pos_ - (block_pos + lfsr_bptr_off(&bptr))),
// mark as erased
(pos_ - block_pos) | LFSR_BPTR_ISERASED,
cksum_);
// mark as uncrystallized and ungrafted
file->b.o.flags |= LFS_o_UNCRYST | LFS_o_UNGRAFT;
return 0;
relocate:;
// allocate a new block
//
// note if we relocate, we rewrite the entire block from
// block_pos using what we can find in our tree
lfs_sblock_t block = lfs_alloc(lfs, true);
if (block < 0) {
return block;
}
lfsr_bptr_init(&bptr,
LFSR_DATA_DISK(block, 0, 0),
// mark as erased
LFSR_BPTR_ISERASED | 0,
0);
}
}
static int lfsr_file_crystallize(lfs_t *lfs, lfsr_file_t *file) {
bool flushable = (
file->cache.pos
>= file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr));
// finish crystallizing
if (lfsr_o_isuncryst(file->b.o.flags)) {
// uncrystallized files must be unsynced
LFS_ASSERT(lfsr_o_isunsync(file->b.o.flags));
// only blocks can be uncrystallized
LFS_ASSERT(lfsr_bptr_isbptr(&file->leaf.bptr));
LFS_ASSERT(lfsr_bptr_iserased(&file->leaf.bptr));
// finish crystallizing the block
int err = lfsr_file_crystallize_(lfs, file,
file->leaf.pos - lfsr_bptr_off(&file->leaf.bptr), -1, -1,
file->cache.pos, file->cache.buffer, file->cache.size);
if (err) {
return err;
}
// mark as crystallized
file->b.o.flags &= ~LFS_o_UNCRYST;
}
// and graft into tree
if (lfsr_o_isungraft(file->b.o.flags)) {
int err = lfsr_file_graft(lfs, file,
file->leaf.pos, file->leaf.weight, 0,
&file->leaf.bptr.data, -1);
if (err) {
return err;
}
// mark as grafted
file->b.o.flags &= ~LFS_o_UNGRAFT;
}
// eagerly mark as flushed if this included all of our cache
if (flushable
&& file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr)
>= file->cache.pos + file->cache.size) {
file->b.o.flags &= ~LFS_o_UNFLUSH;
}
return 0;
}
static int lfsr_file_flush_(lfs_t *lfs, lfsr_file_t *file,
lfs_off_t pos, const uint8_t *buffer, lfs_size_t size) {
// we can skip some btree lookups if we know we are aligned from a
// previous iteration, we already do way too many btree lookups
bool aligned = false;
// if crystallization is disabled, just skip to writing fragments
if (lfs->cfg->crystal_thresh > lfs->cfg->block_size) {
goto fragment;
}
// iteratively write blocks
while (size > 0) {
// mid-crystallization? can we just resume crystallizing?
//
// note that the threshold to resume crystallization (prog_size),
// is often much lower than the threshold to start crystallization
// (crystal_thresh)
lfs_off_t block_start = file->leaf.pos
- lfsr_bptr_off(&file->leaf.bptr);
lfs_off_t block_end = file->leaf.pos
+ lfsr_bptr_size(&file->leaf.bptr);
if (lfsr_bptr_isbptr(&file->leaf.bptr)
&& lfsr_bptr_iserased(&file->leaf.bptr)
&& pos >= block_end
&& pos < block_start + lfs->cfg->block_size
&& pos - block_end < lfs->cfg->crystal_thresh
// need to bail if we can't meet prog alignment
&& (pos + size) - block_end >= lfs->cfg->prog_size) {
int err = lfsr_file_crystallize_(lfs, file,
block_start,
(pos + size) - block_start,
(pos + size) - block_start,
pos, buffer, size);
if (err) {
return err;
}
// update buffer state
lfs_soff_t d = lfs_max(
file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr),
pos) - pos;
pos += d;
buffer += lfs_min(d, size);
size -= lfs_min(d, size);
// we should be aligned now
aligned = true;
continue;
}
// before we can start writing, we need to figure out if we have
// enough fragments to start crystallizing
//
// we do this heuristically, by looking up our worst-case
// crystal neighbors and using them as bounds for our current
// crystal
//
// note this can end up including holes in our crystals, but
// that's ok, we probably don't want small holes preventing
// crystallization anyways
// default to arbitrary alignment
lfs_off_t crystal_start = pos;
lfs_off_t crystal_end = pos + size;
// if we haven't already exceeded our crystallization threshold,
// find left crystal neighbor
lfs_off_t poke = lfs_smax(
crystal_start - (lfs->cfg->crystal_thresh-1),
0);
if (crystal_end - crystal_start < lfs->cfg->crystal_thresh
&& crystal_start > 0
&& poke < lfsr_file_weight(file)
// don't bother looking up left after the first block
&& !aligned) {
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup(lfs, file, poke,
&bid, &weight, &bptr);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if left crystal neighbor is a fragment and there is no
// obvious hole between our own crystal and our neighbor,
// include as a part of our crystal
if (!lfsr_bptr_isbptr(&bptr)
&& lfsr_bptr_size(&bptr) > 0
// hole? holes can be quite large and shouldn't
// trigger crystallization
&& bid-(weight-1) + lfsr_bptr_size(&bptr) >= poke) {
crystal_start = bid-(weight-1);
// otherwise our neighbor determines our crystal boundary
} else {
crystal_start = lfs_min(bid+1, crystal_start);
}
}
// if we haven't already exceeded our crystallization threshold,
// find right crystal neighbor
poke = lfs_min(
crystal_start + (lfs->cfg->crystal_thresh-1),
lfsr_file_weight(file)-1);
if (crystal_end - crystal_start < lfs->cfg->crystal_thresh
&& crystal_end < lfsr_file_weight(file)) {
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup(lfs, file, poke,
&bid, &weight, &bptr);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// if right crystal neighbor is a fragment, include as a part
// of our crystal
if (!lfsr_bptr_isbptr(&bptr)
&& lfsr_bptr_size(&bptr) > 0) {
crystal_end = lfs_max(
bid-(weight-1) + lfsr_bptr_size(&bptr),
crystal_end);
// otherwise treat as crystal boundary
} else {
crystal_end = lfs_max(
bid-(weight-1),
crystal_end);
}
}
// now that we have our crystal guess, we need to decide how to
// write to the file
// below our crystallization threshold? fallback to writing fragments
if (crystal_end - crystal_start < lfs->cfg->crystal_thresh
// enough for prog alignment?
|| crystal_end - crystal_start < lfs->cfg->prog_size) {
goto fragment;
}
// exceeded crystallization threshold? we need to allocate a
// new block
// can we resume crystallizing with the fragments on disk?
block_start = file->leaf.pos
- lfsr_bptr_off(&file->leaf.bptr);
block_end = file->leaf.pos
+ lfsr_bptr_size(&file->leaf.bptr);
if (lfsr_bptr_isbptr(&file->leaf.bptr)
&& lfsr_bptr_iserased(&file->leaf.bptr)
&& crystal_start >= block_end
&& crystal_start < block_start + lfs->cfg->block_size) {
int err = lfsr_file_crystallize_(lfs, file,
block_start,
crystal_end - block_start,
crystal_end - block_start,
pos, buffer, size);
if (err) {
return err;
}
// update buffer state, this may or may not make progress
lfs_soff_t d = lfs_max(
file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr),
pos) - pos;
pos += d;
buffer += lfs_min(d, size);
size -= lfs_min(d, size);
// we should be aligned now
aligned = true;
continue;
}
// if we're mid-crystallization, finish crystallizing the block
// and graft it into our bshrub/btree
int err = lfsr_file_crystallize(lfs, file);
if (err) {
return err;
}
// mark as unerased so lfsr_file_crystallize doesn't try to
// resume crystallizing this block
lfsr_bptr_claim(&file->leaf.bptr);
// before we can crystallize we need to figure out the best
// block alignment, we use the entry immediately to the left of
// our crystal for this
if (crystal_start > 0
&& file->b.shrub.weight > 0
// don't bother to lookup left after the first block
&& !aligned) {
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup(lfs, file,
lfs_min(
crystal_start-1,
file->b.shrub.weight-1),
&bid, &weight, &bptr);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// is our left neighbor in the same block?
if (crystal_start - (bid-(weight-1))
< lfs->cfg->block_size
&& lfsr_bptr_size(&bptr) > 0) {
crystal_start = bid-(weight-1);
// no? is our left neighbor at least our left block neighbor?
// align to block alignment
} else if (crystal_start - (bid-(weight-1))
< 2*lfs->cfg->block_size
&& lfsr_bptr_size(&bptr) > 0) {
crystal_start = bid-(weight-1) + lfs->cfg->block_size;
}
}
// start crystallizing!
//
// lfsr_file_crystallize_ handles block allocation/relocation
err = lfsr_file_crystallize_(lfs, file,
crystal_start,
crystal_end - crystal_start,
crystal_end - crystal_start,
pos, buffer, size);
if (err) {
return err;
}
// update buffer state, this may or may not make progress
lfs_soff_t d = lfs_max(
file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr),
pos) - pos;
pos += d;
buffer += lfs_min(d, size);
size -= lfs_min(d, size);
// we should be aligned now
aligned = true;
}
fragment:;
// iteratively write fragments (inlined leaves)
while (size > 0) {
// before we write fragments, we need to make sure our crystal
// is grafted into the tree
//
// but note we're still tracking its erased state for future
// writes!
if (lfsr_o_isungraft(file->b.o.flags)) {
// graft our crystal
int err = lfsr_file_graft(lfs, file,
file->leaf.pos, file->leaf.weight, 0,
&file->leaf.bptr.data, -1);
if (err) {
return err;
}
// mark as grafted
file->b.o.flags &= ~LFS_o_UNGRAFT;
}
// do we need to discard our leaf? we need to discard fragments
// in case the underlying rbyd compacts, and we need to discard
// overwritten blocks
//
// note we need to discard before attempting to graft since a
// single graft may be split up into multiple commits
//
// unfortunately we don't know where our fragment will end up
// until after the commit, so we can't track it in our leaf
// quite yet
if (!lfsr_bptr_isbptr(&file->leaf.bptr)
|| (pos < file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr)
&& pos + size > file->leaf.pos)) {
lfsr_file_discardleaf(file);
}
// truncate to our fragment size
lfs_off_t fragment_start = pos;
lfs_off_t fragment_end = fragment_start + lfs_min(
size,
lfs->cfg->fragment_size);
lfsr_data_t datas[3];
lfs_size_t data_count = 0;
// do we have a left sibling? don't bother to lookup if fragment
// is already full
if (fragment_end - fragment_start < lfs->cfg->fragment_size
&& fragment_start > 0
&& fragment_start <= lfsr_file_weight(file)
// don't bother to lookup left after first fragment
&& !aligned) {
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup(lfs, file,
fragment_start-1,
&bid, &weight, &bptr);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)
&& lfsr_bptr_isbptr(&bptr)) {
err = lfsr_bptr_ck(lfs, &bptr);
if (err) {
return err;
}
}
#endif
// can we coalesce?
if (bid-(weight-1) + lfsr_bptr_size(&bptr) >= fragment_start
&& fragment_end - (bid-(weight-1))
<= lfs->cfg->fragment_size) {
datas[data_count++] = LFSR_DATA_TRUNCATE(bptr.data,
fragment_start - (bid-(weight-1)));
fragment_start = bid-(weight-1);
fragment_end = fragment_start + lfs_min(
fragment_end - (bid-(weight-1)),
lfs->cfg->fragment_size);
}
}
// append our new data
datas[data_count++] = LFSR_DATA_BUF(
buffer,
fragment_end - pos);
// do we have a right sibling? don't bother to lookup if fragment
// is already full
//
// note this may the same as our left sibling
if (fragment_end - fragment_start < lfs->cfg->fragment_size
&& fragment_end < lfsr_file_weight(file)) {
lfsr_bid_t bid;
lfsr_bid_t weight;
lfsr_bptr_t bptr;
int err = lfsr_file_lookup(lfs, file,
fragment_end,
&bid, &weight, &bptr);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
#ifdef LFS_CKFETCHES
// checking fetches?
if (lfsr_m_isckfetches(lfs->flags)
&& lfsr_bptr_isbptr(&bptr)) {
err = lfsr_bptr_ck(lfs, &bptr);
if (err) {
return err;
}
}
#endif
// can we coalesce?
if (fragment_end < bid-(weight-1) + lfsr_bptr_size(&bptr)
&& bid-(weight-1) + lfsr_bptr_size(&bptr)
- fragment_start
<= lfs->cfg->fragment_size) {
datas[data_count++] = LFSR_DATA_FRUNCATE(bptr.data,
bid-(weight-1) + lfsr_bptr_size(&bptr)
- fragment_end);
fragment_end = fragment_start + lfs_min(
bid-(weight-1) + lfsr_bptr_size(&bptr)
- fragment_start,
lfs->cfg->fragment_size);
}
}
// make sure we didn't overflow our data buffer
LFS_ASSERT(data_count <= 3);
// once we've figured out what fragment to write, graft it into
// our tree
int err = lfsr_file_graft(lfs, file,
fragment_start, fragment_end - fragment_start, 0,
datas, data_count);
if (err) {
return err;
}
// update buffer state
lfs_ssize_t d = fragment_end - pos;
pos += d;
buffer += lfs_min(d, size);
size -= lfs_min(d, size);
// we should be aligned now
aligned = true;
}
return 0;
}
// high-level file writing
lfs_ssize_t lfsr_file_write(lfs_t *lfs, lfsr_file_t *file,
const void *buffer, lfs_size_t size) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't write to readonly files
LFS_ASSERT(!lfsr_o_isrdonly(file->b.o.flags));
// size=0 is a bit special and is guaranteed to have no effects on the
// underlying file, this means no updating file pos or file size
//
// since we need to test for this, just return early
if (size == 0) {
return 0;
}
// would this write make our file larger than our file limit?
int err;
if (size > lfs->file_limit - file->pos) {
err = LFS_ERR_FBIG;
goto failed;
}
// clobber entangled traversals
lfsr_omdir_clobber(lfs, &file->b.o, LFS_t_DIRTY);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// mark as unsynced in case we fail
file->b.o.flags |= LFS_o_UNSYNC;
// update pos if we are appending
lfs_off_t pos = file->pos;
if (lfsr_o_isappend(file->b.o.flags)) {
pos = lfsr_file_size_(file);
}
const uint8_t *buffer_ = buffer;
lfs_size_t written = 0;
while (size > 0) {
// bypass cache?
//
// note we flush our cache before bypassing writes, this isn't
// strictly necessary, but enforces a more intuitive write order
// and avoids weird cases with low-level write heuristics
//
if ((!lfsr_o_isunflush(file->b.o.flags)
|| file->cache.size == 0)
&& size >= lfsr_file_cachesize(lfs, file)) {
err = lfsr_file_flush_(lfs, file,
pos, buffer_, size);
if (err) {
goto failed;
}
// after success, fill our cache with the tail of our write
//
// note we need to clear the cache anyways to avoid any
// out-of-date data
file->cache.pos = pos + size - lfsr_file_cachesize(lfs, file);
lfs_memcpy(file->cache.buffer,
&buffer_[size - lfsr_file_cachesize(lfs, file)],
lfsr_file_cachesize(lfs, file));
file->cache.size = lfsr_file_cachesize(lfs, file);
file->b.o.flags &= ~LFS_o_UNFLUSH;
written += size;
pos += size;
buffer_ += size;
size -= size;
continue;
}
// try to fill our cache
//
// This is a bit delicate, since our cache contains both old and
// new data, but note:
//
// 1. We only write to yet unused cache memory.
//
// 2. Bypassing the cache above means we only write to the
// cache once, and flush at most twice.
//
if ((!lfsr_o_isunflush(file->b.o.flags)
|| file->cache.size == 0)
|| (pos >= file->cache.pos
&& pos <= file->cache.pos + file->cache.size
&& pos
< file->cache.pos
+ lfsr_file_cachesize(lfs, file))) {
// unused cache? we can move it where we need it
if ((!lfsr_o_isunflush(file->b.o.flags)
|| file->cache.size == 0)) {
file->cache.pos = pos;
file->cache.size = 0;
}
lfs_size_t d = lfs_min(
size,
lfsr_file_cachesize(lfs, file)
- (pos - file->cache.pos));
lfs_memcpy(&file->cache.buffer[pos - file->cache.pos],
buffer_,
d);
file->cache.size = lfs_max(
file->cache.size,
pos+d - file->cache.pos);
file->b.o.flags |= LFS_o_UNFLUSH;
written += d;
pos += d;
buffer_ += d;
size -= d;
continue;
}
// flush our cache so the above can't fail
err = lfsr_file_flush_(lfs, file,
file->cache.pos, file->cache.buffer, file->cache.size);
if (err) {
goto failed;
}
file->b.o.flags &= ~LFS_o_UNFLUSH;
}
// update our pos
file->pos = pos;
// flush if requested
if (lfsr_o_isflush(file->b.o.flags)) {
err = lfsr_file_flush(lfs, file);
if (err) {
goto failed;
}
}
// sync if requested
if (lfsr_o_issync(file->b.o.flags)) {
err = lfsr_file_sync(lfs, file);
if (err) {
goto failed;
}
}
return written;
failed:;
// mark as desync so lfsr_file_close doesn't write to disk
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
int lfsr_file_flush(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't write to readonly files
LFS_ASSERT(!lfsr_o_isrdonly(file->b.o.flags));
// do nothing if our file is already flushed, crystallized,
// and grafted
if (!lfsr_o_isunflush(file->b.o.flags)
&& !lfsr_o_isuncryst(file->b.o.flags)
&& !lfsr_o_isungraft(file->b.o.flags)) {
return 0;
}
// unflushed files must be unsynced
LFS_ASSERT(lfsr_o_isunsync(file->b.o.flags));
// clobber entangled traversals
lfsr_omdir_clobber(lfs, &file->b.o, LFS_t_DIRTY);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
int err;
// flush our cache
if (lfsr_o_isunflush(file->b.o.flags)) {
err = lfsr_file_flush_(lfs, file,
file->cache.pos, file->cache.buffer, file->cache.size);
if (err) {
goto failed;
}
// mark as flushed
file->b.o.flags &= ~LFS_o_UNFLUSH;
}
// and crystallize/graft our leaf
err = lfsr_file_crystallize(lfs, file);
if (err) {
goto failed;
}
return 0;
failed:;
// mark as desync so lfsr_file_close doesn't write to disk
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
// this LFS_NOINLINE is to force lfsr_file_sync_ off the stack hot-path
LFS_NOINLINE
static int lfsr_file_sync_(lfs_t *lfs, lfsr_file_t *file) {
// build a commit of any pending file metadata
lfsr_rattr_t rattrs[4];
lfs_size_t rattr_count = 0;
lfsr_data_t name_data;
lfsr_rattr_t shrub_rattrs[1];
lfs_size_t shrub_rattr_count = 0;
lfsr_shrubcommit_t shrub_commit;
// not created yet? need to convert to normal file
if (lfsr_o_isuncreat(file->b.o.flags)) {
// uncreated files must be unsynced
LFS_ASSERT(lfsr_o_isunsync(file->b.o.flags));
int err = lfsr_rbyd_lookup(lfs, &file->b.o.mdir.rbyd,
lfsr_mrid(lfs, file->b.o.mdir.mid), LFSR_TAG_STICKYNOTE,
NULL, &name_data);
if (err) {
// orphan flag but no stickynote tag?
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
rattrs[rattr_count++] = LFSR_RATTR_DATA(
LFSR_TAG_MASK8 | LFSR_TAG_REG, 0,
&name_data);
}
// pending small file flush?
if (lfsr_o_isunflush(file->b.o.flags)) {
// this only works if the file is entirely in our cache
LFS_ASSERT(file->cache.pos == 0);
LFS_ASSERT(file->cache.size == lfsr_file_size_(file));
// reset the bshrub
lfsr_file_discardbshrub(file);
// build a small shrub commit
if (file->cache.size > 0) {
shrub_rattrs[shrub_rattr_count++] = LFSR_RATTR_DATA(
LFSR_TAG_DATA, +file->cache.size,
(const lfsr_data_t*)&file->cache);
LFS_ASSERT(shrub_rattr_count
<= sizeof(shrub_rattrs)/sizeof(lfsr_rattr_t));
shrub_commit.bshrub = &file->b;
shrub_commit.rid = 0;
shrub_commit.rattrs = shrub_rattrs;
shrub_commit.rattr_count = shrub_rattr_count;
rattrs[rattr_count++] = LFSR_RATTR_SHRUBCOMMIT(&shrub_commit);
}
}
// pending file changes?
if (lfsr_o_isunsync(file->b.o.flags)) {
// make sure data is on-disk before committing metadata
int err = lfsr_bd_sync(lfs);
if (err) {
return err;
}
// zero size files should have no bshrub/btree
LFS_ASSERT(lfsr_file_size_(file) > 0
|| lfsr_bshrub_isbnull(&file->b));
// no bshrub/btree?
if (lfsr_bshrub_isbnull(&file->b)
&& !(lfsr_o_isunflush(file->b.o.flags)
&& file->cache.size > 0)) {
rattrs[rattr_count++] = LFSR_RATTR(
LFSR_TAG_RM | LFSR_TAG_MASK8 | LFSR_TAG_STRUCT, 0);
// bshrub?
} else if (lfsr_bshrub_isbshrub(&file->b)
|| (lfsr_o_isunflush(file->b.o.flags)
&& file->cache.size > 0)) {
rattrs[rattr_count++] = LFSR_RATTR_SHRUB(
LFSR_TAG_MASK8 | LFSR_TAG_BSHRUB, 0,
// note we use the staged trunk here
&file->b.shrub_);
// btree?
} else if (lfsr_bshrub_isbtree(&file->b)) {
rattrs[rattr_count++] = LFSR_RATTR_BTREE(
LFSR_TAG_MASK8 | LFSR_TAG_BTREE, 0,
&file->b.shrub);
} else {
LFS_UNREACHABLE();
}
}
// pending custom attributes?
//
// this gets real messy, since users can change custom attributes
// whenever they want without informing littlefs, the best we can do
// is read from disk to manually check if any attributes changed
bool attrs = lfsr_o_isunsync(file->b.o.flags);
if (!attrs) {
for (lfs_size_t i = 0; i < file->cfg->attr_count; i++) {
// skip readonly attrs and lazy attrs
if (lfsr_o_isrdonly(file->cfg->attrs[i].flags)
|| lfsr_a_islazy(file->cfg->attrs[i].flags)) {
continue;
}
// lookup the attr
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &file->b.o.mdir,
LFSR_TAG_ATTR(file->cfg->attrs[i].type),
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// does disk match our attr?
lfs_scmp_t cmp = lfsr_attr_cmp(lfs, &file->cfg->attrs[i],
(err != LFS_ERR_NOENT) ? &data : NULL);
if (cmp < 0) {
return cmp;
}
if (cmp != LFS_CMP_EQ) {
attrs = true;
break;
}
}
}
if (attrs) {
// need to append custom attributes
rattrs[rattr_count++] = LFSR_RATTR_ATTRS(
file->cfg->attrs, file->cfg->attr_count);
}
// pending metadata? looks like we need to write to disk
if (rattr_count > 0) {
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// commit!
LFS_ASSERT(rattr_count <= sizeof(rattrs)/sizeof(lfsr_rattr_t));
int err = lfsr_mdir_commit(lfs, &file->b.o.mdir,
rattrs, rattr_count);
if (err) {
return err;
}
}
return 0;
}
int lfsr_file_sync(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't write to readonly files, if you want to resync call
// lfsr_file_resync
LFS_ASSERT(!lfsr_o_isrdonly(file->b.o.flags));
// removed? sync is just a noop in this case
int err;
if (lfsr_o_iszombie(file->b.o.flags)) {
return 0;
}
// first flush any data in our cache, this is a noop if already
// flushed
//
// note that flush does not change the actual file data, so if
// flush succeeds but mdir commit fails it's ok to fall back to
// our flushed state
//
// though don't flush quite yet if our file is small and can be
// combined with sync in a single commit
if (file->cache.size == lfsr_file_size_(file)
&& file->cache.size <= lfs->cfg->inline_size
&& file->cache.size <= lfs->cfg->fragment_size
&& file->cache.size < lfs->cfg->crystal_thresh) {
if (lfsr_o_isungraft(file->b.o.flags)) {
file->b.o.flags |= LFS_o_UNFLUSH;
}
lfsr_file_discardleaf(file);
} else {
err = lfsr_file_flush(lfs, file);
if (err) {
goto failed;
}
}
// commit any pending metadata to disk
//
// the use of a second function here is mainly to isolate the stack
// costs of lfsr_file_flush and lfsr_file_sync_
//
err = lfsr_file_sync_(lfs, file);
if (err) {
goto failed;
}
// update in-device state
for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
if (lfsr_o_type(o->flags) == LFS_TYPE_REG
&& o->mdir.mid == file->b.o.mdir.mid
// don't double update
&& o != &file->b.o) {
lfsr_file_t *file_ = (lfsr_file_t*)o;
// notify all files of creation
file_->b.o.flags &= ~LFS_o_UNCREAT;
// mark desynced files an unsynced
if (lfsr_o_isdesync(file_->b.o.flags)) {
file_->b.o.flags |= LFS_o_UNSYNC;
// update synced files
} else {
// update flags
file_->b.o.flags &= ~LFS_o_UNSYNC
& ~LFS_o_UNFLUSH
& ~LFS_o_UNCRYST
& ~LFS_o_UNGRAFT;
// update shrubs
file_->b.shrub = file->b.shrub;
// update leaves
file_->leaf = file->leaf;
// update caches
//
// note we need to be careful if caches have different
// sizes, prefer the most recent data in this case
lfs_size_t d = file->cache.size - lfs_min(
lfsr_file_cachesize(lfs, file_),
file->cache.size);
file_->cache.pos = file->cache.pos + d;
lfs_memcpy(file_->cache.buffer,
file->cache.buffer + d,
file->cache.size - d);
file_->cache.size = file->cache.size - d;
// update any custom attrs
for (lfs_size_t i = 0; i < file->cfg->attr_count; i++) {
if (lfsr_o_isrdonly(file->cfg->attrs[i].flags)) {
continue;
}
for (lfs_size_t j = 0; j < file_->cfg->attr_count; j++) {
if (!(file_->cfg->attrs[j].type
== file->cfg->attrs[i].type
&& !lfsr_o_iswronly(
file_->cfg->attrs[j].flags))) {
continue;
}
if (lfsr_attr_isnoattr(&file->cfg->attrs[i])) {
if (file_->cfg->attrs[j].size) {
*file_->cfg->attrs[j].size = LFS_ERR_NOATTR;
}
} else {
lfs_size_t d = lfs_min(
lfsr_attr_size(&file->cfg->attrs[i]),
file_->cfg->attrs[j].buffer_size);
lfs_memcpy(file_->cfg->attrs[j].buffer,
file->cfg->attrs[i].buffer,
d);
if (file_->cfg->attrs[j].size) {
*file_->cfg->attrs[j].size = d;
}
}
}
}
}
// clobber entangled traversals
} else if (lfsr_o_type(o->flags) == LFS_type_TRAVERSAL
&& o->mdir.mid == file->b.o.mdir.mid) {
lfsr_traversal_clobber(lfs, (lfsr_traversal_t*)o);
}
}
// mark as synced
file->b.o.flags &= ~LFS_o_UNSYNC
& ~LFS_o_UNFLUSH
& ~LFS_o_UNCRYST
& ~LFS_o_UNGRAFT
& ~LFS_o_UNCREAT
& ~LFS_O_DESYNC;
return 0;
failed:;
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
int lfsr_file_desync(lfs_t *lfs, lfsr_file_t *file) {
(void)lfs;
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// mark as desynced
file->b.o.flags |= LFS_O_DESYNC;
return 0;
}
int lfsr_file_resync(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// removed? we can't resync
int err;
if (lfsr_o_iszombie(file->b.o.flags)) {
err = LFS_ERR_NOENT;
goto failed;
}
// do nothing if already in-sync
if (lfsr_o_isunsync(file->b.o.flags)) {
// refetch the file struct from disk
err = lfsr_file_fetch(lfs, file, false);
if (err) {
goto failed;
}
}
// mark as resynced
file->b.o.flags &= ~LFS_O_DESYNC;
return 0;
failed:;
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
// other file operations
lfs_soff_t lfsr_file_seek(lfs_t *lfs, lfsr_file_t *file,
lfs_soff_t off, uint8_t whence) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// TODO check for out-of-range?
// figure out our new file position
lfs_off_t pos_;
if (whence == LFS_SEEK_SET) {
pos_ = off;
} else if (whence == LFS_SEEK_CUR) {
pos_ = file->pos + off;
} else if (whence == LFS_SEEK_END) {
pos_ = lfsr_file_size_(file) + off;
} else {
LFS_UNREACHABLE();
}
// out of range?
if (pos_ > lfs->file_limit) {
return LFS_ERR_INVAL;
}
// update file position
file->pos = pos_;
return pos_;
}
lfs_soff_t lfsr_file_tell(lfs_t *lfs, lfsr_file_t *file) {
(void)lfs;
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
return file->pos;
}
lfs_soff_t lfsr_file_rewind(lfs_t *lfs, lfsr_file_t *file) {
(void)lfs;
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
file->pos = 0;
return 0;
}
lfs_soff_t lfsr_file_size(lfs_t *lfs, lfsr_file_t *file) {
(void)lfs;
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
return lfsr_file_size_(file);
}
int lfsr_file_truncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size_) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't write to readonly files
LFS_ASSERT(!lfsr_o_isrdonly(file->b.o.flags));
// do nothing if our size does not change
lfs_off_t size = lfsr_file_size_(file);
if (lfsr_file_size_(file) == size_) {
return 0;
}
// exceeds our file limit?
int err;
if (size_ > lfs->file_limit) {
err = LFS_ERR_FBIG;
goto failed;
}
// clobber entangled traversals
lfsr_omdir_clobber(lfs, &file->b.o, LFS_t_DIRTY);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// mark as unsynced in case we fail
file->b.o.flags |= LFS_o_UNSYNC;
// if our leaf is a fragment or will be fragmented, we need
// to go ahead and graft + discard it, otherwise we risk out-of-date
// fragments as btree commits move things around
//
// note this is mostly to match the behavior of fruncate, where we
// _really_ don't want to discard erased-state
if (!lfsr_bptr_isbptr(&file->leaf.bptr)
|| size_ - lfs_min(file->leaf.pos, size_)
< lfs_min(
lfs->cfg->fragment_thresh,
lfs->cfg->crystal_thresh)) {
err = lfsr_file_crystallize(lfs, file);
if (err) {
goto failed;
}
lfsr_file_discardleaf(file);
}
// truncate our btree
err = lfsr_file_graft(lfs, file,
lfs_min(size, size_), size - lfs_min(size, size_),
+size_ - size,
NULL, 0);
if (err) {
goto failed;
}
// truncate our leaf
if (size_ < file->leaf.pos + lfsr_bptr_size(&file->leaf.bptr)) {
lfsr_bptr_claim(&file->leaf.bptr);
file->b.o.flags &= ~LFS_o_UNCRYST;
}
file->leaf.bptr.data = LFSR_DATA_TRUNCATE(
file->leaf.bptr.data,
size_ - lfs_min(file->leaf.pos, size_));
file->leaf.weight = lfs_min(
file->leaf.weight,
size_ - lfs_min(file->leaf.pos, size_));
file->leaf.pos = lfs_min(file->leaf.pos, size_);
// truncate our cache
file->cache.size = lfs_min(
file->cache.size,
size_ - lfs_min(file->cache.pos, size_));
file->cache.pos = lfs_min(file->cache.pos, size_);
return 0;
failed:;
// mark as desync so lfsr_file_close doesn't write to disk
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
int lfsr_file_fruncate(lfs_t *lfs, lfsr_file_t *file, lfs_off_t size_) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't write to readonly files
LFS_ASSERT(!lfsr_o_isrdonly(file->b.o.flags));
// do nothing if our size does not change
lfs_off_t size = lfsr_file_size_(file);
if (size == size_) {
return 0;
}
// exceeds our file limit?
int err;
if (size_ > lfs->file_limit) {
err = LFS_ERR_FBIG;
goto failed;
}
// clobber entangled traversals
lfsr_omdir_clobber(lfs, &file->b.o, LFS_t_DIRTY);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// mark as unsynced in case we fail
file->b.o.flags |= LFS_o_UNSYNC;
// if our leaf is a fragment or will be fragmented, we need
// to go ahead and graft + discard it, otherwise we risk out-of-date
// fragments as btree commits move things around
//
// note that fruncate is commonly used when logging, where we
// _really_ don't want to discard erased-state, otherwise we'd just
// discard this unconditionally
if (!lfsr_bptr_isbptr(&file->leaf.bptr)
|| lfsr_bptr_size(&file->leaf.bptr) - lfs_min(
lfs_smax(
size - size_ - file->leaf.pos,
0),
lfsr_bptr_size(&file->leaf.bptr))
< lfs_min(
lfs->cfg->fragment_thresh,
lfs->cfg->crystal_thresh)) {
err = lfsr_file_crystallize(lfs, file);
if (err) {
goto failed;
}
lfsr_file_discardleaf(file);
}
// fruncate our btree
err = lfsr_file_graft(lfs, file,
0, lfs_smax(size - size_, 0),
+size_ - size,
NULL, 0);
if (err) {
goto failed;
}
// fruncate our leaf
if ((lfs_soff_t)(size - size_)
> (lfs_soff_t)(file->leaf.pos
+ lfsr_bptr_size(&file->leaf.bptr))) {
lfsr_bptr_claim(&file->leaf.bptr);
file->b.o.flags &= ~LFS_o_UNCRYST;
}
file->leaf.bptr.data = LFSR_DATA_FRUNCATE(
file->leaf.bptr.data,
lfsr_bptr_size(&file->leaf.bptr) - lfs_min(
lfs_smax(
size - size_ - file->leaf.pos,
0),
lfsr_bptr_size(&file->leaf.bptr)));
file->leaf.weight -= lfs_min(
lfs_smax(
size - size_ - file->leaf.pos,
0),
file->leaf.weight);
file->leaf.pos -= lfs_smin(
size - size_,
file->leaf.pos);
// fruncate our cache
lfs_memmove(file->cache.buffer,
&file->cache.buffer[lfs_min(
lfs_smax(
size - size_ - file->cache.pos,
0),
file->cache.size)],
file->cache.size - lfs_min(
lfs_smax(
size - size_ - file->cache.pos,
0),
file->cache.size));
file->cache.size -= lfs_min(
lfs_smax(
size - size_ - file->cache.pos,
0),
file->cache.size);
file->cache.pos -= lfs_smin(
size - size_,
file->cache.pos);
// fruncate _does_ update pos, to keep the same pos relative to end
// of file, though we can't let pos go negative
file->pos -= lfs_smin(
size - size_,
file->pos);
return 0;
failed:;
// mark as desync so lfsr_file_close doesn't write to disk
file->b.o.flags |= LFS_O_DESYNC;
return err;
}
// file check functions
static int lfsr_file_traverse_(lfs_t *lfs, const lfsr_bshrub_t *bshrub,
lfsr_btraversal_t *bt,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_bptr_t *bptr) {
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_bshrub_traverse(lfs, bshrub, bt,
bid_, &tag, &data);
if (err) {
return err;
}
// decode bptrs
if (tag == LFSR_TAG_BLOCK) {
err = lfsr_data_readbptr(lfs, &data,
bptr);
if (err) {
return err;
}
} else {
bptr->data = data;
}
if (tag_) {
*tag_ = tag;
}
return 0;
}
static int lfsr_file_traverse(lfs_t *lfs, const lfsr_file_t *file,
lfsr_btraversal_t *bt,
lfsr_bid_t *bid_, lfsr_tag_t *tag_, lfsr_bptr_t *bptr) {
return lfsr_file_traverse_(lfs, &file->b, bt,
bid_, tag_, bptr);
}
static int lfsr_file_ck(lfs_t *lfs, const lfsr_file_t *file,
uint32_t flags) {
// validate ungrafted data block?
if (lfsr_t_isckdata(flags)
&& lfsr_o_isungraft(file->b.o.flags)) {
LFS_ASSERT(lfsr_bptr_isbptr(&file->leaf.bptr));
int err = lfsr_bptr_ck(lfs, &file->leaf.bptr);
if (err) {
return err;
}
}
// traverse the file's bshrub/btree
lfsr_btraversal_t bt;
lfsr_btraversal_init(&bt);
while (true) {
lfsr_tag_t tag;
lfsr_bptr_t bptr;
int err = lfsr_file_traverse(lfs, file, &bt,
NULL, &tag, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// validate btree nodes?
//
// this may end up revalidating some btree nodes when ckfetches
// is enabled, but we need to revalidate cached btree nodes or
// we risk missing errors in ckmeta scans
if ((lfsr_t_isckmeta(flags)
|| lfsr_t_isckdata(flags))
&& tag == LFSR_TAG_BRANCH) {
lfsr_rbyd_t *rbyd = (lfsr_rbyd_t*)bptr.data.u.buffer;
err = lfsr_rbyd_fetchck(lfs, rbyd,
rbyd->blocks[0], rbyd->trunk,
rbyd->cksum);
if (err) {
return err;
}
}
// validate data blocks?
if (lfsr_t_isckdata(flags)
&& tag == LFSR_TAG_BLOCK) {
err = lfsr_bptr_ck(lfs, &bptr);
if (err) {
return err;
}
}
}
return 0;
}
int lfsr_file_ckmeta(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't read from writeonly files
LFS_ASSERT(!lfsr_o_iswronly(file->b.o.flags));
return lfsr_file_ck(lfs, file,
LFS_T_RDONLY | LFS_T_CKMETA);
}
int lfsr_file_ckdata(lfs_t *lfs, lfsr_file_t *file) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &file->b.o));
// can't read from writeonly files
LFS_ASSERT(!lfsr_o_iswronly(file->b.o.flags));
return lfsr_file_ck(lfs, file,
LFS_T_RDONLY | LFS_T_CKMETA | LFS_T_CKDATA);
}
/// High-level filesystem operations ///
// needed in lfs_init
static int lfs_deinit(lfs_t *lfs);
// initialize littlefs state, assert on bad configuration
static int lfs_init(lfs_t *lfs, uint32_t flags,
const struct lfs_config *cfg) {
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_M_RDWR
| LFS_M_RDONLY
| LFS_M_FLUSH
| LFS_M_SYNC
| LFS_IFDEF_REVDBG(LFS_M_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_M_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_M_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_M_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_M_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_M_CKDATACKSUMREADS, 0))) == 0);
#if defined(LFS_REVNOISE) && defined(LFS_REVDBG)
// LFS_M_REVDBG and LFS_M_REVNOISE are incompatible
LFS_ASSERT(!lfsr_m_isrevdbg(flags) || !lfsr_m_isrevnoise(flags));
#endif
// TODO this all needs to be cleaned up
lfs->cfg = cfg;
int err = 0;
// validate that the lfs-cfg sizes were initiated properly before
// performing any arithmetic logics with them
LFS_ASSERT(lfs->cfg->read_size != 0);
LFS_ASSERT(lfs->cfg->prog_size != 0);
LFS_ASSERT(lfs->cfg->rcache_size != 0);
LFS_ASSERT(lfs->cfg->pcache_size != 0);
// cache sizes must be a multiple of their operation sizes
LFS_ASSERT(lfs->cfg->rcache_size % lfs->cfg->read_size == 0);
LFS_ASSERT(lfs->cfg->pcache_size % lfs->cfg->prog_size == 0);
// block_size must be a multiple of both prog/read size
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->read_size == 0);
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->prog_size == 0);
// block_size is currently limited to 28-bits
LFS_ASSERT(lfs->cfg->block_size <= 0x0fffffff);
#ifdef LFS_GC
// unknown gc flags?
LFS_ASSERT((lfs->cfg->gc_flags & ~(
LFS_GC_MKCONSISTENT
| LFS_GC_LOOKAHEAD
| LFS_GC_COMPACT
| LFS_GC_CKMETA
| LFS_GC_CKDATA)) == 0);
#endif
// check that gc_compact_thresh makes sense
//
// metadata can't be compacted below block_size/2, and metadata can't
// exceed a block
LFS_ASSERT(lfs->cfg->gc_compact_thresh == 0
|| lfs->cfg->gc_compact_thresh >= lfs->cfg->block_size/2);
LFS_ASSERT(lfs->cfg->gc_compact_thresh == (lfs_size_t)-1
|| lfs->cfg->gc_compact_thresh <= lfs->cfg->block_size);
// inline_size must be <= block_size/4
LFS_ASSERT(lfs->cfg->inline_size <= lfs->cfg->block_size/4);
// fragment_size must be <= block_size/4
LFS_ASSERT(lfs->cfg->fragment_size <= lfs->cfg->block_size/4);
// fragment_thresh > crystal_thresh is probably a mistake
LFS_ASSERT(lfs->cfg->fragment_thresh == (lfs_size_t)-1
|| lfs->cfg->fragment_thresh <= lfs->cfg->crystal_thresh);
// setup flags
lfs->flags = flags
// assume we contain orphans until proven otherwise
| LFS_I_MKCONSISTENT
// default to an empty lookahead
| LFS_I_LOOKAHEAD
// default to assuming we need compaction somewhere, worst case
// this just makes lfsr_fs_gc read more than is strictly needed
| LFS_I_COMPACT
// default to needing a ckmeta/ckdata scan
| LFS_I_CKMETA
| LFS_I_CKDATA;
// copy block_count so we can mutate it
lfs->block_count = lfs->cfg->block_count;
// setup read cache
lfs->rcache.block = 0;
lfs->rcache.off = 0;
lfs->rcache.size = 0;
if (lfs->cfg->rcache_buffer) {
lfs->rcache.buffer = lfs->cfg->rcache_buffer;
} else {
lfs->rcache.buffer = lfs_malloc(lfs->cfg->rcache_size);
if (!lfs->rcache.buffer) {
err = LFS_ERR_NOMEM;
goto failed;
}
}
// setup program cache
lfs->pcache.block = 0;
lfs->pcache.off = 0;
lfs->pcache.size = 0;
if (lfs->cfg->pcache_buffer) {
lfs->pcache.buffer = lfs->cfg->pcache_buffer;
} else {
lfs->pcache.buffer = lfs_malloc(lfs->cfg->pcache_size);
if (!lfs->pcache.buffer) {
err = LFS_ERR_NOMEM;
goto failed;
}
}
#ifdef LFS_CKMETAPARITY
// setup ptail, nothing should actually check off=0
lfs->ptail.block = 0;
lfs->ptail.off = 0;
#endif
// setup lookahead buffer, note mount finishes initializing this after
// we establish a decent pseudo-random seed
LFS_ASSERT(lfs->cfg->lookahead_size > 0);
if (lfs->cfg->lookahead_buffer) {
lfs->lookahead.buffer = lfs->cfg->lookahead_buffer;
} else {
lfs->lookahead.buffer = lfs_malloc(lfs->cfg->lookahead_size);
if (!lfs->lookahead.buffer) {
err = LFS_ERR_NOMEM;
goto failed;
}
}
lfs->lookahead.window = 0;
lfs->lookahead.off = 0;
lfs->lookahead.size = 0;
lfs->lookahead.ckpoint = 0;
lfs_alloc_discard(lfs);
// check that the size limits are sane
LFS_ASSERT(lfs->cfg->name_limit <= LFS_NAME_MAX);
lfs->name_limit = lfs->cfg->name_limit;
if (!lfs->name_limit) {
lfs->name_limit = LFS_NAME_MAX;
}
LFS_ASSERT(lfs->cfg->file_limit <= LFS_FILE_MAX);
lfs->file_limit = lfs->cfg->file_limit;
if (!lfs->file_limit) {
lfs->file_limit = LFS_FILE_MAX;
}
// TODO do we need to recalculate these after mount?
// find the number of bits to use for recycle counters
//
// Add 1, to include the initial erase, multiply by 2, since we
// alternate which metadata block we erase each compaction, and limit
// to 28-bits so we always have some bits to determine the most recent
// revision.
if (lfs->cfg->block_recycles != -1) {
lfs->recycle_bits = lfs_min(
lfs_nlog2(2*(lfs->cfg->block_recycles+1)+1)-1,
28);
} else {
lfs->recycle_bits = -1;
}
// calculate the upper-bound cost of a single rbyd attr after compaction
//
// Note that with rebalancing during compaction, we know the number
// of inner nodes is roughly the same as the number of tags. Unfortunately,
// our inner node encoding is rather poor, requiring 2 alts and terminating
// with a 4-byte null tag:
//
// a_0 = 3t + 4
//
// If we could build each trunk perfectly, we could get this down to only
// 1 alt per tag. But this would require unbounded RAM:
//
// a_inf = 2t
//
// Or, if you build a bounded number of layers perfectly:
//
// 2t 3t + 4
// a_1 = -- + ------
// 2 2
//
// a_n = 2t*(1-2^-n) + (3t + 4)*2^-n
//
// But this would be a tradeoff in code complexity.
//
// The worst-case tag encoding, t, depends on our size-limit and
// block-size. The weight can never exceed size-limit, and the size/jump
// field can never exceed a single block:
//
// t = 2 + log128(file_limit+1) + log128(block_size)
//
// Note this is different from LFSR_TAG_DSIZE, which is the worst case
// tag encoding at compile-time.
//
uint8_t tag_estimate
= 2
+ (lfs_nlog2(lfs->file_limit+1)+7-1)/7
+ (lfs_nlog2(lfs->cfg->block_size)+7-1)/7;
LFS_ASSERT(tag_estimate <= LFSR_TAG_DSIZE);
lfs->rattr_estimate = 3*tag_estimate + 4;
// calculate the upper-bound cost of a single mdir attr after compaction
//
// This is the same as rattr_estimate, except we can assume a weight<=1.
//
tag_estimate
= 2
+ 1
+ (lfs_nlog2(lfs->cfg->block_size)+7-1)/7;
LFS_ASSERT(tag_estimate <= LFSR_TAG_DSIZE);
lfs->mattr_estimate = 3*tag_estimate + 4;
// calculate the number of bits we need to reserve for mdir rids
//
// Worst case (or best case?) each metadata entry is a single tag. In
// theory each entry also needs a did+name, but with power-of-two
// rounding, this is negligible
//
// Assuming a _perfect_ compaction algorithm (requires unbounded RAM),
// each tag also needs ~1 alt, this gives us:
//
// block_size block_size
// mrids = ---------- = ----------
// a_inf 2t
//
// Assuming t=4 bytes, the minimum tag encoding:
//
// block_size block_size
// mrids = ---------- = ----------
// 2*4 8
//
// Note we can't assume ~1/2 block utilization here, as an mdir may
// temporarily fill with more mids before compaction occurs.
//
// Rounding up to the nearest power of two:
//
// (block_size)
// mbits = nlog2(----------) = nlog2(block_size) - 3
// ( 8 )
//
// Note if you divide before the nlog2, make sure to use ceiling
// division for compatibility if block_size is not aligned to 8 bytes.
//
// Note note our actual compaction algorithm is not perfect, and
// requires 3t+4 bytes per tag, or with t=4 bytes => ~block_size/12
// metadata entries per block. But we intentionally don't leverage this
// to maintain compatibility with a theoretical perfect implementation.
//
lfs->mbits = lfs_nlog2(lfs->cfg->block_size) - 3;
// zero linked-list of opened mdirs
lfs->omdirs = NULL;
// zero gstate
lfs->gcksum = 0;
lfs->gcksum_p = 0;
lfs->gcksum_d = 0;
lfs->grm.queue[0] = -1;
lfs->grm.queue[1] = -1;
lfs_memset(lfs->grm_p, 0, LFSR_GRM_DSIZE);
lfs_memset(lfs->grm_d, 0, LFSR_GRM_DSIZE);
return 0;
failed:;
lfs_deinit(lfs);
return err;
}
static int lfs_deinit(lfs_t *lfs) {
// free allocated memory
if (!lfs->cfg->rcache_buffer) {
lfs_free(lfs->rcache.buffer);
}
if (!lfs->cfg->pcache_buffer) {
lfs_free(lfs->pcache.buffer);
}
if (!lfs->cfg->lookahead_buffer) {
lfs_free(lfs->lookahead.buffer);
}
return 0;
}
/// Mount/unmount ///
// compatibility flags
//
// - RCOMPAT => Must understand to read the filesystem
// - WCOMPAT => Must understand to write to the filesystem
// - OCOMPAT => No understanding necessary, we don't really use these
//
// note, "understanding" does not necessarily mean support
//
#define LFSR_RCOMPAT_NONSTANDARD 0x00000001 // Non-standard filesystem format
#define LFSR_RCOMPAT_WRONLY 0x00000002 // Reading is disallowed
#define LFSR_RCOMPAT_BMOSS 0x00000010 // Files may use inlined data
#define LFSR_RCOMPAT_BSPROUT 0x00000020 // Files may use block pointers
#define LFSR_RCOMPAT_BSHRUB 0x00000040 // Files may use inlined btrees
#define LFSR_RCOMPAT_BTREE 0x00000080 // Files may use btrees
#define LFSR_RCOMPAT_MMOSS 0x00000100 // May use an inlined mdir
#define LFSR_RCOMPAT_MSPROUT 0x00000200 // May use an mdir pointer
#define LFSR_RCOMPAT_MSHRUB 0x00000400 // May use an inlined mtree
#define LFSR_RCOMPAT_MTREE 0x00000800 // May use an mtree
#define LFSR_RCOMPAT_GRM 0x00001000 // Global-remove in use
// internal
#define LFSR_rcompat_OVERFLOW 0x80000000 // Can't represent all flags
#define LFSR_RCOMPAT_COMPAT \
(LFSR_RCOMPAT_BSHRUB \
| LFSR_RCOMPAT_BTREE \
| LFSR_RCOMPAT_MMOSS \
| LFSR_RCOMPAT_MTREE \
| LFSR_RCOMPAT_GRM)
#define LFSR_WCOMPAT_NONSTANDARD 0x00000001 // Non-standard filesystem format
#define LFSR_WCOMPAT_RDONLY 0x00000002 // Writing is disallowed
#define LFSR_WCOMPAT_DIR 0x00000010 // Directory files in use
#define LFSR_WCOMPAT_GCKSUM 0x00001000 // Global-checksum in use
// internal
#define LFSR_wcompat_OVERFLOW 0x80000000 // Can't represent all flags
#define LFSR_WCOMPAT_COMPAT \
(LFSR_WCOMPAT_DIR \
| LFSR_WCOMPAT_GCKSUM)
#define LFSR_OCOMPAT_NONSTANDARD 0x00000001 // Non-standard filesystem format
// internal
#define LFSR_ocompat_OVERFLOW 0x80000000 // Can't represent all flags
#define LFSR_OCOMPAT_COMPAT 0
typedef uint32_t lfsr_rcompat_t;
typedef uint32_t lfsr_wcompat_t;
typedef uint32_t lfsr_ocompat_t;
static inline bool lfsr_rcompat_isincompat(lfsr_rcompat_t rcompat) {
return rcompat != LFSR_RCOMPAT_COMPAT;
}
static inline bool lfsr_wcompat_isincompat(lfsr_wcompat_t wcompat) {
return wcompat != LFSR_WCOMPAT_COMPAT;
}
static inline bool lfsr_ocompat_isincompat(lfsr_ocompat_t ocompat) {
return ocompat != LFSR_OCOMPAT_COMPAT;
}
// compat flags on-disk encoding
//
// little-endian, truncated bits must be assumed zero
static int lfsr_data_readcompat(lfs_t *lfs, lfsr_data_t *data,
uint32_t *compat) {
// allow truncated compat flags
uint8_t buf[4] = {0};
lfs_ssize_t d = lfsr_data_read(lfs, data, buf, 4);
if (d < 0) {
return d;
}
*compat = lfs_fromle32(buf);
// if any out-of-range flags are set, set the internal overflow bit,
// this is a compromise in correctness and and compat-flag complexity
//
// we don't really care about performance here
while (lfsr_data_size(*data) > 0) {
uint8_t b;
lfs_ssize_t d = lfsr_data_read(lfs, data, &b, 1);
if (d < 0) {
return d;
}
if (b != 0x00) {
*compat |= 0x80000000;
break;
}
}
return 0;
}
// all the compat parsing is basically the same, so try to reuse code
static inline int lfsr_data_readrcompat(lfs_t *lfs, lfsr_data_t *data,
lfsr_rcompat_t *rcompat) {
return lfsr_data_readcompat(lfs, data, rcompat);
}
static inline int lfsr_data_readwcompat(lfs_t *lfs, lfsr_data_t *data,
lfsr_wcompat_t *wcompat) {
return lfsr_data_readcompat(lfs, data, wcompat);
}
static inline int lfsr_data_readocompat(lfs_t *lfs, lfsr_data_t *data,
lfsr_ocompat_t *ocompat) {
return lfsr_data_readcompat(lfs, data, ocompat);
}
// disk geometry
//
// note these are stored minus 1 to avoid overflow issues
struct lfsr_geometry {
lfs_off_t block_size;
lfs_off_t block_count;
};
// geometry on-disk encoding
static lfsr_data_t lfsr_data_fromgeometry(const lfsr_geometry_t *geometry,
uint8_t buffer[static LFSR_GEOMETRY_DSIZE]) {
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(geometry->block_size-1, &buffer[d], 4);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
d_ = lfs_toleb128(geometry->block_count-1, &buffer[d], 5);
if (d_ < 0) {
LFS_UNREACHABLE();
}
d += d_;
return LFSR_DATA_BUF(buffer, d);
}
static int lfsr_data_readgeometry(lfs_t *lfs, lfsr_data_t *data,
lfsr_geometry_t *geometry) {
int err = lfsr_data_readlleb128(lfs, data, &geometry->block_size);
if (err) {
return err;
}
err = lfsr_data_readleb128(lfs, data, &geometry->block_count);
if (err) {
return err;
}
geometry->block_size += 1;
geometry->block_count += 1;
return 0;
}
static int lfsr_mountmroot(lfs_t *lfs, const lfsr_mdir_t *mroot) {
// check the disk version
uint8_t version[2] = {0, 0};
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_VERSION,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
lfs_ssize_t d = lfsr_data_read(lfs, &data, version, 2);
if (d < 0) {
return err;
}
}
if (version[0] != LFS_DISK_VERSION_MAJOR
|| version[1] > LFS_DISK_VERSION_MINOR) {
LFS_ERROR("Incompatible version v%"PRId32".%"PRId32" "
"(!= v%"PRId32".%"PRId32")",
version[0],
version[1],
LFS_DISK_VERSION_MAJOR,
LFS_DISK_VERSION_MINOR);
return LFS_ERR_NOTSUP;
}
// check for any rcompatflags, we must understand these to read
// the filesystem
lfsr_rcompat_t rcompat = 0;
err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_RCOMPAT,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
err = lfsr_data_readrcompat(lfs, &data, &rcompat);
if (err) {
return err;
}
}
if (lfsr_rcompat_isincompat(rcompat)) {
LFS_ERROR("Incompatible rcompat flags 0x%0"PRIx32" (!= 0x%0"PRIx32")",
rcompat,
LFSR_RCOMPAT_COMPAT);
return LFS_ERR_NOTSUP;
}
// check for any wcompatflags, we must understand these to write
// the filesystem
lfsr_wcompat_t wcompat = 0;
err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_WCOMPAT,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
err = lfsr_data_readwcompat(lfs, &data, &wcompat);
if (err) {
return err;
}
}
if (lfsr_wcompat_isincompat(wcompat)) {
LFS_WARN("Incompatible wcompat flags 0x%0"PRIx32" (!= 0x%0"PRIx32")",
wcompat,
LFSR_WCOMPAT_COMPAT);
// we can continue if rdonly
if (!lfsr_m_isrdonly(lfs->flags)) {
return LFS_ERR_NOTSUP;
}
}
// we don't bother to check for any ocompatflags, we would just
// ignore these anyways
// check the on-disk geometry
lfsr_geometry_t geometry;
err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_GEOMETRY,
NULL, &data);
if (err) {
if (err == LFS_ERR_NOENT) {
LFS_ERROR("No geometry found");
return LFS_ERR_INVAL;
}
return err;
}
err = lfsr_data_readgeometry(lfs, &data, &geometry);
if (err) {
return err;
}
// either block_size matches or it doesn't, we don't support variable
// block_sizes
if (geometry.block_size != lfs->cfg->block_size) {
LFS_ERROR("Incompatible block size %"PRId32" (!= %"PRId32")",
geometry.block_size,
lfs->cfg->block_size);
return LFS_ERR_NOTSUP;
}
// on-disk block_count must be <= configured block_count
if (geometry.block_count > lfs->cfg->block_count) {
LFS_ERROR("Incompatible block count %"PRId32" (> %"PRId32")",
geometry.block_count,
lfs->cfg->block_count);
return LFS_ERR_NOTSUP;
}
lfs->block_count = geometry.block_count;
// read the name limit
lfs_size_t name_limit = 0xff;
err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_NAMELIMIT,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
err = lfsr_data_readleb128(lfs, &data, &name_limit);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err == LFS_ERR_CORRUPT) {
name_limit = -1;
}
}
if (name_limit > lfs->name_limit) {
LFS_ERROR("Incompatible name limit %"PRId32" (> %"PRId32")",
name_limit,
lfs->name_limit);
return LFS_ERR_NOTSUP;
}
lfs->name_limit = name_limit;
// read the file limit
lfs_off_t file_limit = 0x7fffffff;
err = lfsr_mdir_lookup(lfs, mroot, LFSR_TAG_FILELIMIT,
NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
err = lfsr_data_readleb128(lfs, &data, &file_limit);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err == LFS_ERR_CORRUPT) {
file_limit = -1;
}
}
if (file_limit > lfs->file_limit) {
LFS_ERROR("Incompatible file limit %"PRId32" (> %"PRId32")",
file_limit,
lfs->file_limit);
return LFS_ERR_NOTSUP;
}
lfs->file_limit = file_limit;
// check for unknown configs
lfsr_tag_t tag;
err = lfsr_mdir_lookupnext(lfs, mroot, LFSR_TAG_UNKNOWNCONFIG,
&tag, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT
&& lfsr_tag_suptype(tag) == LFSR_TAG_CONFIG) {
LFS_ERROR("Unknown config 0x%04"PRIx16,
tag);
return LFS_ERR_NOTSUP;
}
return 0;
}
static int lfsr_mountinited(lfs_t *lfs) {
// mark mroot as invalid to prevent lfsr_mtree_traverse from getting
// confused
lfs->mroot.mid = -1;
lfs->mroot.rbyd.blocks[0] = -1;
lfs->mroot.rbyd.blocks[1] = -1;
// default to no mtree, this is allowed and implies all files are inlined
// in the mroot
lfsr_btree_init(&lfs->mtree);
// zero gcksum/gdeltas, we'll read these from our mdirs
lfs->gcksum = 0;
lfsr_fs_flushgdelta(lfs);
// traverse the mtree rooted at mroot 0x{1,0}
//
// we do validate btree inner nodes here, how can we trust our
// mdirs are valid if we haven't checked the btree inner nodes at
// least once?
lfsr_traversal_t t;
lfsr_traversal_init(&t, LFS_T_RDONLY | LFS_T_MTREEONLY | LFS_T_CKMETA);
while (true) {
lfsr_tag_t tag;
lfsr_bptr_t bptr;
int err = lfsr_mtree_traverse(lfs, &t,
&tag, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// found an mdir?
if (tag == LFSR_TAG_MDIR) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr.data.u.buffer;
// found an mroot?
if (mdir->mid == -1) {
// check for the magic string, all mroot should have this
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, mdir, LFSR_TAG_MAGIC,
NULL, &data);
if (err) {
if (err == LFS_ERR_NOENT) {
LFS_ERROR("No littlefs magic found");
return LFS_ERR_CORRUPT;
}
return err;
}
// treat corrupted magic as no magic
lfs_scmp_t cmp = lfsr_data_cmp(lfs, data, "littlefs", 8);
if (cmp < 0) {
return cmp;
}
if (cmp != LFS_CMP_EQ) {
LFS_ERROR("No littlefs magic found");
return LFS_ERR_CORRUPT;
}
// are we the last mroot?
err = lfsr_mdir_lookup(lfs, mdir, LFSR_TAG_MROOT,
NULL, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
// track active mroot
lfs->mroot = *mdir;
// mount/validate config in active mroot
err = lfsr_mountmroot(lfs, &lfs->mroot);
if (err) {
return err;
}
}
}
// build gcksum out of mdir cksums
lfs->gcksum ^= mdir->rbyd.cksum;
// collect any gdeltas from this mdir
err = lfsr_fs_consumegdelta(lfs, mdir);
if (err) {
return err;
}
// found an mtree inner-node?
} else if (tag == LFSR_TAG_BRANCH) {
lfsr_rbyd_t *rbyd = (lfsr_rbyd_t*)bptr.data.u.buffer;
// found the root of the mtree? keep track of this
if (lfs->mtree.weight == 0) {
lfs->mtree = *rbyd;
}
} else {
LFS_UNREACHABLE();
}
}
// validate gcksum by comparing its cube against the gcksumdeltas
//
// The use of cksum^3 here is important to avoid trivial
// gcksumdeltas. If we use a linear function (cksum, crc32c(cksum),
// cksum^2, etc), the state of the filesystem cancels out when
// calculating a new gcksumdelta:
//
// d_i = t(g') - t(g)
// d_i = t(g + c_i) - t(g)
// d_i = t(g) + t(c_i) - t(g)
// d_i = t(c_i)
//
// Using cksum^3 prevents this from happening:
//
// d_i = (g + c_i)^3 - g^3
// d_i = (g + c_i)(g + c_i)(g + c_i) - g^3
// d_i = (g^2 + gc_i + gc_i + c_i^2)(g + c_i) - g^3
// d_i = (g^2 + c_i^2)(g + c_i) - g^3
// d_i = g^3 + gc_i^2 + g^2c_i + c_i^3 - g^3
// d_i = gc_i^2 + g^2c_i + c_i^3
//
// cksum^3 also has some other nice properties, providing a perfect
// 1->1 mapping of t(g) in 2^31 fields, and losing at most 3-bits of
// info when calculating d_i.
//
if (lfs_crc32c_cube(lfs->gcksum) != lfs->gcksum_d) {
LFS_ERROR("Found gcksum mismatch, cksum^3 %08"PRIx32" "
"(!= %08"PRIx32")",
lfs_crc32c_cube(lfs->gcksum),
lfs->gcksum_d);
return LFS_ERR_CORRUPT;
}
// keep track of the current gcksum
lfs->gcksum_p = lfs->gcksum;
// once we've mounted and derived a pseudo-random seed, initialize our
// block allocator
//
// the purpose of this is to avoid bad wear patterns such as always
// allocating blocks near the beginning of disk after a power-loss
//
lfs->lookahead.window = lfs->gcksum % lfs->block_count;
// TODO should the consumegdelta above take gstate/gdelta as a parameter?
// keep track of the current gstate on disk
lfs_memcpy(lfs->grm_p, lfs->grm_d, LFSR_GRM_DSIZE);
// decode grm so we can report any removed files as missing
int err = lfsr_data_readgrm(lfs,
&LFSR_DATA_BUF(lfs->grm_p, LFSR_GRM_DSIZE));
if (err) {
// TODO switch to read-only?
return err;
}
// found pending grms? this should only happen if we lost power
if (lfsr_grm_count(lfs) == 2) {
LFS_INFO("Found pending grm %"PRId32".%"PRId32" %"PRId32".%"PRId32,
lfsr_dbgmbid(lfs, lfs->grm.queue[0]),
lfsr_dbgmrid(lfs, lfs->grm.queue[0]),
lfsr_dbgmbid(lfs, lfs->grm.queue[1]),
lfsr_dbgmrid(lfs, lfs->grm.queue[1]));
} else if (lfsr_grm_count(lfs) == 1) {
LFS_INFO("Found pending grm %"PRId32".%"PRId32,
lfsr_dbgmbid(lfs, lfs->grm.queue[0]),
lfsr_dbgmrid(lfs, lfs->grm.queue[0]));
}
return 0;
}
// needed in lfsr_mount
static int lfsr_fs_gc_(lfs_t *lfs, lfsr_traversal_t *t,
uint32_t flags, lfs_soff_t steps);
int lfsr_mount(lfs_t *lfs, uint32_t flags,
const struct lfs_config *cfg) {
#ifdef LFS_YES_RDONLY
flags |= LFS_M_RDONLY;
#endif
#ifdef LFS_YES_FLUSH
flags |= LFS_M_FLUSH;
#endif
#ifdef LFS_YES_SYNC
flags |= LFS_M_SYNC;
#endif
#ifdef LFS_YES_REVDBG
flags |= LFS_M_REVDBG;
#endif
#ifdef LFS_YES_REVNOISE
flags |= LFS_M_REVNOISE;
#endif
#ifdef LFS_YES_CKPROGS
flags |= LFS_M_CKPROGS;
#endif
#ifdef LFS_YES_CKFETCHES
flags |= LFS_M_CKFETCHES;
#endif
#ifdef LFS_YES_CKMETAPARITY
flags |= LFS_M_CKMETAPARITY;
#endif
#ifdef LFS_YES_CKDATACKSUMREADS
flags |= LFS_M_CKDATACKSUMREADS;
#endif
#ifdef LFS_YES_MKCONSISTENT
flags |= LFS_M_MKCONSISTENT;
#endif
#ifdef LFS_YES_LOOKAHEAD
flags |= LFS_M_LOOKAHEAD;
#endif
#ifdef LFS_YES_COMPACT
flags |= LFS_M_COMPACT;
#endif
#ifdef LFS_YES_CKMETA
flags |= LFS_M_CKMETA;
#endif
#ifdef LFS_YES_CKDATA
flags |= LFS_M_CKDATA
#endif
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_M_RDWR
| LFS_M_RDONLY
| LFS_M_FLUSH
| LFS_M_SYNC
| LFS_IFDEF_REVDBG(LFS_M_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_M_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_M_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_M_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_M_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_M_CKDATACKSUMREADS, 0)
| LFS_M_MKCONSISTENT
| LFS_M_LOOKAHEAD
| LFS_M_COMPACT
| LFS_M_CKMETA
| LFS_M_CKDATA)) == 0);
// these flags require a writable filesystem
LFS_ASSERT(!lfsr_m_isrdonly(flags) || !lfsr_t_ismkconsistent(flags));
LFS_ASSERT(!lfsr_m_isrdonly(flags) || !lfsr_t_islookahead(flags));
LFS_ASSERT(!lfsr_m_isrdonly(flags) || !lfsr_t_iscompact(flags));
int err = lfs_init(lfs,
flags & (
LFS_M_RDWR
| LFS_M_RDONLY
| LFS_M_FLUSH
| LFS_M_SYNC
| LFS_IFDEF_REVDBG(LFS_M_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_M_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_M_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_M_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_M_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_M_CKDATACKSUMREADS, 0)),
cfg);
if (err) {
return err;
}
err = lfsr_mountinited(lfs);
if (err) {
goto failed;
}
// run gc if requested
if (flags & (
LFS_M_MKCONSISTENT
| LFS_M_LOOKAHEAD
| LFS_M_COMPACT
| LFS_M_CKMETA
| LFS_M_CKDATA)) {
lfsr_traversal_t t;
err = lfsr_fs_gc_(lfs, &t,
flags & (
LFS_M_MKCONSISTENT
| LFS_M_LOOKAHEAD
| LFS_M_COMPACT
| LFS_M_CKMETA
| LFS_M_CKDATA),
-1);
if (err) {
goto failed;
}
}
// TODO this should use any configured values
LFS_INFO("Mounted littlefs v%"PRId32".%"PRId32" %"PRId32"x%"PRId32" "
"0x{%"PRIx32",%"PRIx32"}.%"PRIx32" w%"PRId32".%"PRId32", "
"cksum %08"PRIx32,
LFS_DISK_VERSION_MAJOR,
LFS_DISK_VERSION_MINOR,
lfs->cfg->block_size,
lfs->block_count,
lfs->mroot.rbyd.blocks[0],
lfs->mroot.rbyd.blocks[1],
lfsr_rbyd_trunk(&lfs->mroot.rbyd),
lfs->mtree.weight >> lfs->mbits,
1 << lfs->mbits,
lfs->gcksum);
return 0;
failed:;
// make sure we clean up on error
lfs_deinit(lfs);
return err;
}
int lfsr_unmount(lfs_t *lfs) {
// all files/dirs should be closed before lfsr_unmount
LFS_ASSERT(lfs->omdirs == NULL
// special case for our gc traversal handle
|| LFS_IFDEF_GC(
(lfs->omdirs == &lfs->gc.t.b.o
&& lfs->gc.t.b.o.next == NULL),
false));
return lfs_deinit(lfs);
}
/// Format ///
static int lfsr_formatinited(lfs_t *lfs) {
for (int i = 0; i < 2; i++) {
// write superblock to both rbyds in the root mroot to hopefully
// avoid mounting an older filesystem on disk
lfsr_rbyd_t rbyd = {.blocks[0]=i, .eoff=0, .trunk=0};
int err = lfsr_bd_erase(lfs, rbyd.blocks[0]);
if (err) {
return err;
}
// the initial revision count is arbitrary, but it's nice to have
// something here to tell the initial mroot apart from btree nodes
// (rev=0), it's also useful for start with -1 and 0 in the upper
// bits to help test overflow/sequence comparison
uint32_t rev = (((uint32_t)i-1) << 28)
| (((1 << (28-lfs_smax(lfs->recycle_bits, 0)))-1)
& 0x00216968);
err = lfsr_rbyd_appendrev(lfs, &rbyd, rev);
if (err) {
return err;
}
// our initial superblock contains a couple things:
// - our magic string, "littlefs"
// - any format-time configuration
// - the root's bookmark tag, which reserves did = 0 for the root
err = lfsr_rbyd_appendrattrs(lfs, &rbyd, -1, -1, -1, LFSR_RATTRS(
LFSR_RATTR_BUF(
LFSR_TAG_MAGIC, 0,
"littlefs", 8),
LFSR_RATTR_BUF(
LFSR_TAG_VERSION, 0,
((const uint8_t[2]){
LFS_DISK_VERSION_MAJOR,
LFS_DISK_VERSION_MINOR}), 2),
LFSR_RATTR_LE32(
LFSR_TAG_RCOMPAT, 0,
LFSR_RCOMPAT_COMPAT),
LFSR_RATTR_LE32(
LFSR_TAG_WCOMPAT, 0,
LFSR_WCOMPAT_COMPAT),
LFSR_RATTR_GEOMETRY(
LFSR_TAG_GEOMETRY, 0,
(&(lfsr_geometry_t){
lfs->cfg->block_size,
lfs->cfg->block_count})),
LFSR_RATTR_LLEB128(
LFSR_TAG_NAMELIMIT, 0,
lfs->name_limit),
LFSR_RATTR_LEB128(
LFSR_TAG_FILELIMIT, 0,
lfs->file_limit),
LFSR_RATTR_NAME(
LFSR_TAG_BOOKMARK, +1,
0, NULL, 0)));
if (err) {
return err;
}
// append initial gcksum
uint32_t cksum = rbyd.cksum;
err = lfsr_rbyd_appendrattr_(lfs, &rbyd, LFSR_RATTR_LE32(
LFSR_TAG_GCKSUMDELTA, 0, lfs_crc32c_cube(cksum)));
if (err) {
return err;
}
// and commit
err = lfsr_rbyd_appendcksum_(lfs, &rbyd, cksum);
if (err) {
return err;
}
}
// sync on-disk state
int err = lfsr_bd_sync(lfs);
if (err) {
return err;
}
return 0;
}
int lfsr_format(lfs_t *lfs, uint32_t flags,
const struct lfs_config *cfg) {
#ifdef LFS_YES_REVDBG
flags |= LFS_F_REVDBG;
#endif
#ifdef LFS_YES_REVNOISE
flags |= LFS_F_REVNOISE;
#endif
#ifdef LFS_YES_CKPROGS
flags |= LFS_F_CKPROGS;
#endif
#ifdef LFS_YES_CKFETCHES
flags |= LFS_F_CKFETCHES;
#endif
#ifdef LFS_YES_CKMETAPARITY
flags |= LFS_F_CKMETAPARITY;
#endif
#ifdef LFS_YES_CKDATACKSUMREADS
flags |= LFS_F_CKDATACKSUMREADS;
#endif
#ifdef LFS_YES_CKMETA
flags |= LFS_F_CKMETA;
#endif
#ifdef LFS_YES_CKDATA
flags |= LFS_F_CKDATA
#endif
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_F_RDWR
| LFS_IFDEF_REVDBG(LFS_F_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_F_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_F_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_F_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_F_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_F_CKDATACKSUMREADS, 0)
| LFS_F_CKMETA
| LFS_F_CKDATA)) == 0);
int err = lfs_init(lfs,
flags & (
LFS_F_RDWR
| LFS_IFDEF_REVDBG(LFS_F_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_F_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_F_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_F_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_F_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_F_CKDATACKSUMREADS, 0)),
cfg);
if (err) {
return err;
}
LFS_INFO("Formatting littlefs v%"PRId32".%"PRId32" %"PRId32"x%"PRId32,
LFS_DISK_VERSION_MAJOR,
LFS_DISK_VERSION_MINOR,
lfs->cfg->block_size,
lfs->block_count);
err = lfsr_formatinited(lfs);
if (err) {
goto failed;
}
// test that mount works with our formatted disk
err = lfsr_mountinited(lfs);
if (err) {
goto failed;
}
// run gc if requested
if (flags & (
LFS_F_CKMETA
| LFS_F_CKDATA)) {
lfsr_traversal_t t;
err = lfsr_fs_gc_(lfs, &t,
flags & (
LFS_F_CKMETA
| LFS_F_CKDATA),
-1);
if (err) {
goto failed;
}
}
return lfs_deinit(lfs);
failed:;
// make sure we clean up on error
lfs_deinit(lfs);
return err;
}
/// Other filesystem things ///
int lfsr_fs_stat(lfs_t *lfs, struct lfs_fsinfo *fsinfo) {
// return various filesystem flags
fsinfo->flags = lfs->flags & (
LFS_I_RDONLY
| LFS_I_FLUSH
| LFS_I_SYNC
| LFS_IFDEF_REVDBG(LFS_I_REVDBG, 0)
| LFS_IFDEF_REVNOISE(LFS_I_REVNOISE, 0)
| LFS_IFDEF_CKPROGS(LFS_I_CKPROGS, 0)
| LFS_IFDEF_CKFETCHES(LFS_I_CKFETCHES, 0)
| LFS_IFDEF_CKMETAPARITY(LFS_I_CKMETAPARITY, 0)
| LFS_IFDEF_CKDATACKSUMREADS(LFS_I_CKDATACKSUMREADS, 0)
| LFS_I_MKCONSISTENT
| LFS_I_LOOKAHEAD
| LFS_I_COMPACT
| LFS_I_CKMETA
| LFS_I_CKDATA);
// some flags we calculate on demand
fsinfo->flags |= (lfsr_grm_count(lfs) > 0) ? LFS_I_MKCONSISTENT : 0;
// return filesystem config, this may come from disk
fsinfo->block_size = lfs->cfg->block_size;
fsinfo->block_count = lfs->block_count;
fsinfo->name_limit = lfs->name_limit;
fsinfo->file_limit = lfs->file_limit;
return 0;
}
lfs_ssize_t lfsr_fs_usage(lfs_t *lfs) {
lfs_size_t count = 0;
lfsr_traversal_t t;
lfsr_traversal_init(&t, LFS_T_RDONLY);
while (true) {
lfsr_tag_t tag;
lfsr_bptr_t bptr;
int err = lfsr_mtree_traverse(lfs, &t,
&tag, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
// count the number of blocks we see, yes this may result in duplicates
if (tag == LFSR_TAG_MDIR) {
count += 2;
} else if (tag == LFSR_TAG_BRANCH) {
count += 1;
} else if (tag == LFSR_TAG_BLOCK) {
count += 1;
} else {
LFS_UNREACHABLE();
}
}
return count;
}
// consistency stuff
static int lfsr_fs_fixgrm(lfs_t *lfs) {
if (lfsr_grm_count(lfs) == 2) {
LFS_INFO("Fixing grm %"PRId32".%"PRId32" %"PRId32".%"PRId32,
lfsr_dbgmbid(lfs, lfs->grm.queue[0]),
lfsr_dbgmrid(lfs, lfs->grm.queue[0]),
lfsr_dbgmbid(lfs, lfs->grm.queue[1]),
lfsr_dbgmrid(lfs, lfs->grm.queue[1]));
} else if (lfsr_grm_count(lfs) == 1) {
LFS_INFO("Fixing grm %"PRId32".%"PRId32,
lfsr_dbgmbid(lfs, lfs->grm.queue[0]),
lfsr_dbgmrid(lfs, lfs->grm.queue[0]));
}
while (lfsr_grm_count(lfs) > 0) {
LFS_ASSERT(lfs->grm.queue[0] != -1);
// find our mdir
lfsr_mdir_t mdir;
int err = lfsr_mtree_lookup(lfs, lfs->grm.queue[0],
&mdir);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// we also use grm to track orphans that need to be cleaned up,
// which means it may not match the on-disk state, which means
// we need to revert manually on error
lfsr_grm_t grm_p = lfs->grm;
// mark grm as taken care of
lfsr_grm_pop(lfs);
// checkpoint the allocator
lfs_alloc_ckpoint(lfs);
// remove the rid while atomically updating our grm
err = lfsr_mdir_commit(lfs, &mdir, LFSR_RATTRS(
LFSR_RATTR(LFSR_TAG_RM, -1)));
if (err) {
// revert grm manually
lfs->grm = grm_p;
return err;
}
}
return 0;
}
static int lfsr_mdir_mkconsistent(lfs_t *lfs, lfsr_mdir_t *mdir) {
// save the current mid
lfsr_mid_t mid = mdir->mid;
// iterate through mids looking for orphans
mdir->mid = LFSR_MID(lfs, mdir->mid, 0);
int err;
while (lfsr_mrid(lfs, mdir->mid) < (lfsr_srid_t)mdir->rbyd.weight) {
// is this mid open? well we're not an orphan then, skip
//
// note we can't rely on lfsr_mdir_lookup's internal orphan
// checks as we also need to treat desynced/zombied files as
// non-orphans
if (lfsr_omdir_ismidopen(lfs, mdir->mid, -1)) {
mdir->mid += 1;
continue;
}
// is this mid marked as a stickynote?
err = lfsr_rbyd_lookup(lfs, &mdir->rbyd,
lfsr_mrid(lfs, mdir->mid), LFSR_TAG_STICKYNOTE,
NULL, NULL);
if (err) {
if (err == LFS_ERR_NOENT) {
mdir->mid += 1;
continue;
}
goto failed;
}
// we found an orphaned stickynote, remove
LFS_INFO("Fixing orphaned stickynote %"PRId32".%"PRId32,
lfsr_dbgmbid(lfs, mdir->mid),
lfsr_dbgmrid(lfs, mdir->mid));
lfs_alloc_ckpoint(lfs);
err = lfsr_mdir_commit(lfs, mdir, LFSR_RATTRS(
LFSR_RATTR(LFSR_TAG_RM, -1)));
if (err) {
goto failed;
}
}
// restore the current mid
mdir->mid = mid;
return 0;
failed:;
// restore the current mid
mdir->mid = mid;
return err;
}
static int lfsr_fs_fixorphans(lfs_t *lfs) {
// LFS_T_MKCONSISTENT really just removes orphans
lfsr_traversal_t t;
lfsr_traversal_init(&t,
LFS_T_RDWR | LFS_T_MTREEONLY | LFS_T_MKCONSISTENT);
while (true) {
lfsr_bptr_t bptr;
int err = lfsr_mtree_gc(lfs, &t,
NULL, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
}
return 0;
}
// prepare the filesystem for mutation
int lfsr_fs_mkconsistent(lfs_t *lfs) {
// filesystem must be writeable
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags));
// fix pending grms
if (lfsr_grm_count(lfs) > 0) {
int err = lfsr_fs_fixgrm(lfs);
if (err) {
return err;
}
}
// fix orphaned stickynotes
//
// this must happen after fixgrm, since removing orphaned
// stickynotes risks outdating the grm
//
if (lfsr_t_ismkconsistent(lfs->flags)) {
int err = lfsr_fs_fixorphans(lfs);
if (err) {
return err;
}
}
return 0;
}
// filesystem check functions
static int lfsr_fs_ck(lfs_t *lfs, uint32_t flags) {
// we leave this up to lfsr_mtree_traverse
lfsr_traversal_t t;
lfsr_traversal_init(&t, flags);
while (true) {
lfsr_bptr_t bptr;
int err = lfsr_mtree_traverse(lfs, &t,
NULL, &bptr);
if (err) {
if (err == LFS_ERR_NOENT) {
break;
}
return err;
}
}
return 0;
}
int lfsr_fs_ckmeta(lfs_t *lfs) {
return lfsr_fs_ck(lfs, LFS_T_RDONLY | LFS_T_CKMETA);
}
int lfsr_fs_ckdata(lfs_t *lfs) {
return lfsr_fs_ck(lfs, LFS_T_RDONLY | LFS_T_CKMETA | LFS_T_CKDATA);
}
// get the filesystem checksum
int lfsr_fs_cksum(lfs_t *lfs, uint32_t *cksum) {
*cksum = lfs->gcksum;
return 0;
}
// low-level filesystem gc
//
// runs the traversal until all work is completed, which may take
// multiple passes
static int lfsr_fs_gc_(lfs_t *lfs, lfsr_traversal_t *t,
uint32_t flags, lfs_soff_t steps) {
// unknown gc flags?
//
// we should have check these earlier, but it doesn't hurt to
// double check
LFS_ASSERT((flags & ~(
LFS_GC_MKCONSISTENT
| LFS_GC_LOOKAHEAD
| LFS_GC_COMPACT
| LFS_GC_CKMETA
| LFS_GC_CKDATA)) == 0);
// these flags require a writable filesystem
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags) || !lfsr_t_ismkconsistent(flags));
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags) || !lfsr_t_islookahead(flags));
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags) || !lfsr_t_iscompact(flags));
// some flags don't make sense when only traversing the mtree
LFS_ASSERT(!lfsr_t_ismtreeonly(flags) || !lfsr_t_islookahead(flags));
LFS_ASSERT(!lfsr_t_ismtreeonly(flags) || !lfsr_t_isckdata(flags));
// fix pending grms if requested
if (lfsr_t_ismkconsistent(flags)
&& lfsr_grm_count(lfs) > 0) {
int err = lfsr_fs_fixgrm(lfs);
if (err) {
return err;
}
}
// do we have any pending work?
uint32_t pending = flags & (
(lfs->flags & (
LFS_I_MKCONSISTENT
| LFS_I_LOOKAHEAD
| LFS_I_COMPACT
| LFS_I_CKMETA
| LFS_I_CKDATA)));
while (pending && (lfs_off_t)steps > 0) {
// checkpoint the allocator to maximize any lookahead scans
lfs_alloc_ckpoint(lfs);
// start a new traversal?
if (!lfsr_omdir_isopen(lfs, &t->b.o)) {
lfsr_traversal_init(t, pending);
lfsr_omdir_open(lfs, &t->b.o);
}
// don't bother with lookahead if we've mutated
if (lfsr_t_isdirty(t->b.o.flags)
|| lfsr_t_ismutated(t->b.o.flags)) {
t->b.o.flags &= ~LFS_GC_LOOKAHEAD;
}
// will this traversal still make progress? no? start over
if (!(t->b.o.flags & (
LFS_GC_MKCONSISTENT
| LFS_GC_LOOKAHEAD
| LFS_GC_COMPACT
| LFS_GC_CKMETA
| LFS_GC_CKDATA))) {
lfsr_omdir_close(lfs, &t->b.o);
continue;
}
// do we really need a full traversal?
if (!(t->b.o.flags & (
LFS_GC_LOOKAHEAD
| LFS_GC_CKMETA
| LFS_GC_CKDATA))) {
t->b.o.flags |= LFS_T_MTREEONLY;
}
// progress gc
lfsr_bptr_t bptr;
int err = lfsr_mtree_gc(lfs, t,
NULL, &bptr);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// end of traversal?
if (err == LFS_ERR_NOENT) {
lfsr_omdir_close(lfs, &t->b.o);
// clear any pending flags we make progress on
pending &= lfs->flags & (
LFS_I_MKCONSISTENT
| LFS_I_LOOKAHEAD
| LFS_I_COMPACT
| LFS_I_CKMETA
| LFS_I_CKDATA);
}
// decrement steps
if (steps > 0) {
steps -= 1;
}
}
return 0;
}
#ifdef LFS_GC
// incremental filesystem gc
//
// perform any pending janitorial work
int lfsr_fs_gc(lfs_t *lfs) {
return lfsr_fs_gc_(lfs, &lfs->gc.t,
lfs->cfg->gc_flags,
(lfs->cfg->gc_steps)
? lfs->cfg->gc_steps
: 1);
}
#endif
// unperform janitorial work
int lfsr_fs_unck(lfs_t *lfs, uint32_t flags) {
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_I_MKCONSISTENT
| LFS_I_LOOKAHEAD
| LFS_I_COMPACT
| LFS_I_CKMETA
| LFS_I_CKDATA)) == 0);
// reset the requested flags
lfs->flags |= flags;
#ifdef LFS_GC
// and clear from any ongoing traversals
//
// lfsr_fs_gc will terminate early if it discovers it can no longer
// make progress
lfs->gc.t.b.o.flags &= ~flags;
#endif
return 0;
}
// attempt to grow the filesystem
int lfsr_fs_grow(lfs_t *lfs, lfs_size_t block_count_) {
// filesystem must be writeable
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags));
// shrinking the filesystem is not supported
LFS_ASSERT(block_count_ >= lfs->block_count);
// do nothing if block_count doesn't change
if (block_count_ == lfs->block_count) {
return 0;
}
// Note we do _not_ call lfsr_fs_mkconsistent here. This is a bit scary,
// but we should be ok as long as we patch grms in lfsr_mdir_commit and
// only commit to the mroot.
//
// Calling lfsr_fs_mkconsistent risks locking our filesystem up trying
// to fix grms/orphans before we can commit the new filesystem size. If
// we don't, we should always be able to recover a stuck filesystem with
// lfsr_fs_grow.
LFS_INFO("Growing littlefs %"PRId32"x%"PRId32" -> %"PRId32"x%"PRId32,
lfs->cfg->block_size, lfs->block_count,
lfs->cfg->block_size, block_count_);
// keep track of our current block_count in case we fail
lfs_size_t block_count = lfs->block_count;
// we can use the new blocks immediately as long as the commit
// with the new block_count is atomic
lfs->block_count = block_count_;
// discard stale lookahead buffer
lfs_alloc_discard(lfs);
// update our on-disk config
lfs_alloc_ckpoint(lfs);
int err = lfsr_mdir_commit(lfs, &lfs->mroot, LFSR_RATTRS(
LFSR_RATTR_GEOMETRY(
LFSR_TAG_GEOMETRY, 0,
(&(lfsr_geometry_t){
lfs->cfg->block_size,
block_count_}))));
if (err) {
goto failed;
}
return 0;
failed:;
// restore block_count
lfs->block_count = block_count;
// discard clobbered lookahead buffer
lfs_alloc_discard(lfs);
return err;
}
/// High-level filesystem traversal ///
// needed in lfsr_traversal_open
static int lfsr_traversal_rewind_(lfs_t *lfs, lfsr_traversal_t *t);
int lfsr_traversal_open(lfs_t *lfs, lfsr_traversal_t *t, uint32_t flags) {
// already open?
LFS_ASSERT(!lfsr_omdir_isopen(lfs, &t->b.o));
// unknown flags?
LFS_ASSERT((flags & ~(
LFS_T_RDONLY
| LFS_T_RDWR
| LFS_T_MTREEONLY
| LFS_T_MKCONSISTENT
| LFS_T_LOOKAHEAD
| LFS_T_COMPACT
| LFS_T_CKMETA
| LFS_T_CKDATA)) == 0);
// writeable traversals require a writeable filesystem
LFS_ASSERT(!lfsr_m_isrdonly(lfs->flags) || lfsr_t_isrdonly(flags));
// these flags require a writable traversal
LFS_ASSERT(!lfsr_t_isrdonly(flags) || !lfsr_t_ismkconsistent(flags));
LFS_ASSERT(!lfsr_t_isrdonly(flags) || !lfsr_t_islookahead(flags));
LFS_ASSERT(!lfsr_t_isrdonly(flags) || !lfsr_t_iscompact(flags));
// some flags don't make sense when only traversing the mtree
LFS_ASSERT(!lfsr_t_ismtreeonly(flags) || !lfsr_t_islookahead(flags));
LFS_ASSERT(!lfsr_t_ismtreeonly(flags) || !lfsr_t_isckdata(flags));
// setup traversal state
t->b.o.flags = flags | lfsr_o_typeflags(LFS_type_TRAVERSAL);
// let rewind initialize/reset things
int err = lfsr_traversal_rewind_(lfs, t);
if (err) {
return err;
}
// add to tracked mdirs
lfsr_omdir_open(lfs, &t->b.o);
return 0;
}
int lfsr_traversal_close(lfs_t *lfs, lfsr_traversal_t *t) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &t->b.o));
// remove from tracked mdirs
lfsr_omdir_close(lfs, &t->b.o);
return 0;
}
int lfsr_traversal_read(lfs_t *lfs, lfsr_traversal_t *t,
struct lfs_tinfo *tinfo) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &t->b.o));
// check for pending grms every step, just in case some other
// operation introduced new grms
if (lfsr_t_ismkconsistent(t->b.o.flags)
&& lfsr_grm_count(lfs) > 0) {
// swap dirty/mutated flags while mutating
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
int err = lfsr_fs_fixgrm(lfs);
if (err) {
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
return err;
}
t->b.o.flags = lfsr_t_swapdirty(t->b.o.flags);
}
// checkpoint the allocator to maximize any lookahead scans
lfs_alloc_ckpoint(lfs);
while (true) {
// some redund blocks left over?
if (t->blocks[0] != -1) {
// write our traversal info
tinfo->btype = lfsr_t_btype(t->b.o.flags);
tinfo->block = t->blocks[0];
t->blocks[0] = t->blocks[1];
t->blocks[1] = -1;
return 0;
}
// find next block
lfsr_tag_t tag;
lfsr_bptr_t bptr;
int err = lfsr_mtree_gc(lfs, t,
&tag, &bptr);
if (err) {
return err;
}
// figure out type/blocks
if (tag == LFSR_TAG_MDIR) {
lfsr_mdir_t *mdir = (lfsr_mdir_t*)bptr.data.u.buffer;
lfsr_t_setbtype(&t->b.o.flags, LFS_BTYPE_MDIR);
t->blocks[0] = mdir->rbyd.blocks[0];
t->blocks[1] = mdir->rbyd.blocks[1];
} else if (tag == LFSR_TAG_BRANCH) {
lfsr_t_setbtype(&t->b.o.flags, LFS_BTYPE_BTREE);
lfsr_rbyd_t *rbyd = (lfsr_rbyd_t*)bptr.data.u.buffer;
t->blocks[0] = rbyd->blocks[0];
t->blocks[1] = -1;
} else if (tag == LFSR_TAG_BLOCK) {
lfsr_t_setbtype(&t->b.o.flags, LFS_BTYPE_DATA);
t->blocks[0] = lfsr_bptr_block(&bptr);
t->blocks[1] = -1;
} else {
LFS_UNREACHABLE();
}
}
}
static void lfsr_traversal_clobber(lfs_t *lfs, lfsr_traversal_t *t) {
(void)lfs;
// mroot/mtree? transition to mdir iteration
if (lfsr_t_tstate(t->b.o.flags) < LFSR_TSTATE_MDIRS) {
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIRS);
t->b.o.mdir.mid = 0;
lfsr_bshrub_init(&t->b);
t->ot = NULL;
// in-mtree mdir? increment the mid (to make progress) and reset to
// mdir iteration
} else if (lfsr_t_tstate(t->b.o.flags) < LFSR_TSTATE_OMDIRS) {
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_MDIR);
t->b.o.mdir.mid += 1;
lfsr_bshrub_init(&t->b);
t->ot = NULL;
// opened mdir? skip to next omdir
} else if (lfsr_t_tstate(t->b.o.flags) < LFSR_TSTATE_DONE) {
lfsr_t_settstate(&t->b.o.flags, LFSR_TSTATE_OMDIRS);
lfsr_bshrub_init(&t->b);
t->ot = (t->ot) ? t->ot->next : NULL;
// done traversals should never need clobbering
} else {
LFS_UNREACHABLE();
}
// and clear any pending blocks
t->blocks[0] = -1;
t->blocks[1] = -1;
}
static int lfsr_traversal_rewind_(lfs_t *lfs, lfsr_traversal_t *t) {
(void)lfs;
// reset traversal
lfsr_traversal_init(t,
t->b.o.flags
& ~LFS_t_DIRTY
& ~LFS_t_MUTATED
& ~LFS_t_TSTATE);
// and clear any pending blocks
t->blocks[0] = -1;
t->blocks[1] = -1;
return 0;
}
int lfsr_traversal_rewind(lfs_t *lfs, lfsr_traversal_t *t) {
LFS_ASSERT(lfsr_omdir_isopen(lfs, &t->b.o));
return lfsr_traversal_rewind_(lfs, t);
}
// that's it! you've reached the end! go home!
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