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ba505c2a376813421b2ced98fb04abd7a97c257b
littlefs/scripts/dbgbtree.py
Christopher Haster ba505c2a37 Implemented scratch file basics 
"Scratch files" are a new file type added to solve the zero-sized
file problem. Though they have a few other uses that may be quite
valuable.

The "zero-sized file problem" is a common surprise for users, where what
seems like a simple file create+write operation:

  lfs_file_open(&lfs, &file, "hi",
          LFS_O_WRONLY | LFS_O_CREAT | LFS_O_EXCL);
  lfs_file_write(&lfs, &file, "hello!", strlen("hello!"));
  lfs_file_close(&lfs, &file);

Can end up create a zero-sized file under powerloss, breaking user
assumptions and their code.

The tricky thing is that this is actually correct behavior as defined by
POSIX. `open` with O_CREAT creats a file entry immediately, which is
initially zero-sized. And the fact that power can be lost between `open`
and `close` isn't really avoidable.

But this is a common enough footgun that it's probably worth deviating
from POSIX here.

But how to avoid zero-sized files exactly? First thought: Delay the file
creation until sync/close, tracking uncreated files in-device until
then. This solves the problem and avoids any intermediary state if we
lose power, but came with a number of headaches:

1. Since we delay file creation, we don't immediately write the filename
   to disk on open. This implies we need to keep the filename allocated
   in RAM until the first sync/close call.

   The requirement to keep the filename allocated for new files until
   first sync/close could be added to open, and with the option to call
   sync immediately to save the filename (and accept the risk of
   zero-sized files), I don't think it would be _that_ bad of an API.

   But it would still be pretty bad. Extra bad because 1. there's no
   way to warn on misuse at compile-time, 2. use-after-free bugs have a
   tendency to go unnoticed annoyingly often, 3. it's a regression from
   the previous API, and 4. who the heck reads the more-or-less same
   `open` documentation for every filesystem they adopt.

2. Without an allocated mid, tracking files internally gets a lot
   harder. The best option I could think of was to keep the opened-file
   linked-list sorted by mid + (in-device) file name.

   This did not feel like a great solutiona and was going to add more
   code cost.

3. Handling mdir splits containing uncreated files adds another
   headache. Complicated lfsr_mdir_estimate further as it needs to
   decide in which mdir the uncreated files will end up, and potentially
   split on a filename that isn't even created yet.

4. Since the number of uncreated files can be potentially unbounded, you
   can't prevent an mdir from filling up with only uncreated files. On
   disk this ends up looking like an "empty" mdir, which need specially
   handling in littlefs to reclaim after powerloss.

   Support for empty mdirs -- the orphaned mdir scan -- was already
   added earlier. We already scan each mdir to build gstate, so it
   doesn't really add much cost.

Notice that last bullet point? We already scan each mdir during mount.
Why not, instead of scanning for orphaned mdirs, scan for orphaned
files?

So this leads to the idea of "scratch files". Instead of actually
delaying file creation, fake it. Create a scratch file during open, and
on the first sync/close, convert it to a regular file. If we lose power,
scan for scratch files during mount, and remove them on first write.

Some tradeoffs:

1. The orphan scan for scratch files is a bit more expensive than for
   mdirs on storage with large block sizes. We need to look at each file
   entry vs just each mdir, which pushed the runtime up to O(BlogB) vs
   O(B).

   Though if you also consider large mtrees, the worst case is still
   O(nlogn).

2. Creating intermediate scratch files adds another commit to file
   creation.

   This is probably not a big issue for flash, but may be more of a
   concern on devices with large prog sizes.

3. Scratch files complicate unrelated mkdir/rename/etc code a bit, since
   we need to consider what happens when the dest is a scratch file.

But the end result is simple. And simple is good. Both for
implementation headaches, and code size. Even if the on-disk state is
conceptually more complicated.

You may have noticed these scratch files are basically isomorphic to
just setting an "uncreated" flag on the file, and that's true. There may
have been a simpler route to end up with the design, but hey, as long as
it works.

As a plus, scratch files present a solution for a couple other things:

1. Removing an open file can become a scratch file until closed.

2. Scratch files can be used as temporary files. Open a file with
   O_DESYNC and never call sync and you have yourself a temporary file.

   Maybe in the future we should add O_TMPFILE to avoid the need for
   unique filenames, but that is low priority.
2024-02-03 18:15:29 -06:00

1067 lines
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#!/usr/bin/env python3
import bisect
import collections as co
import itertools as it
import math as m
import os
import struct
TAG_NULL = 0x0000
TAG_CONFIG = 0x0000
TAG_MAGIC = 0x0003
TAG_VERSION = 0x0004
TAG_OCOMPATFLAGS = 0x0005
TAG_RCOMPATFLAGS = 0x0006
TAG_WCOMPATFLAGS = 0x0007
TAG_BLOCKSIZE = 0x0008
TAG_BLOCKCOUNT = 0x0009
TAG_NAMELIMIT = 0x000a
TAG_SIZELIMIT = 0x000b
TAG_GDELTA = 0x0100
TAG_GRMDELTA = 0x0100
TAG_NAME = 0x0200
TAG_REG = 0x0201
TAG_DIR = 0x0202
TAG_SCRATCH = 0x0203
TAG_BOOKMARK = 0x0204
TAG_STRUCT = 0x0300
TAG_DATA = 0x0300
TAG_BLOCK = 0x0304
TAG_BSHRUB = 0x0308
TAG_BTREE = 0x030c
TAG_DID = 0x0310
TAG_BECKSUM = 0x0314
TAG_BRANCH = 0x031c
TAG_MROOT = 0x0321
TAG_MDIR = 0x0325
TAG_MTREE = 0x032c
TAG_UATTR = 0x0400
TAG_SATTR = 0x0600
TAG_SHRUB = 0x1000
TAG_CKSUM = 0x3000
TAG_ECKSUM = 0x3100
TAG_ALT = 0x4000
TAG_GT = 0x2000
TAG_R = 0x1000
# some ways of block geometry representations
# 512 -> 512
# 512x16 -> (512, 16)
# 0x200x10 -> (512, 16)
def bdgeom(s):
s = s.strip()
b = 10
if s.startswith('0x') or s.startswith('0X'):
s = s[2:]
b = 16
elif s.startswith('0o') or s.startswith('0O'):
s = s[2:]
b = 8
elif s.startswith('0b') or s.startswith('0B'):
s = s[2:]
b = 2
if 'x' in s:
s, s_ = s.split('x', 1)
return (int(s, b), int(s_, b))
else:
return int(s, b)
# parse some rbyd addr encodings
# 0xa -> [0xa]
# 0xa.c -> [(0xa, 0xc)]
# 0x{a,b} -> [0xa, 0xb]
# 0x{a,b}.c -> [(0xa, 0xc), (0xb, 0xc)]
def rbydaddr(s):
s = s.strip()
b = 10
if s.startswith('0x') or s.startswith('0X'):
s = s[2:]
b = 16
elif s.startswith('0o') or s.startswith('0O'):
s = s[2:]
b = 8
elif s.startswith('0b') or s.startswith('0B'):
s = s[2:]
b = 2
trunk = None
if '.' in s:
s, s_ = s.split('.', 1)
trunk = int(s_, b)
if s.startswith('{') and '}' in s:
ss = s[1:s.find('}')].split(',')
else:
ss = [s]
addr = []
for s in ss:
if trunk is not None:
addr.append((int(s, b), trunk))
else:
addr.append(int(s, b))
return addr
def crc32c(data, crc=0):
crc ^= 0xffffffff
for b in data:
crc ^= b
for j in range(8):
crc = (crc >> 1) ^ ((crc & 1) * 0x82f63b78)
return 0xffffffff ^ crc
def popc(x):
return bin(x).count('1')
def fromle32(data):
return struct.unpack('<I', data[0:4].ljust(4, b'\0'))[0]
def fromleb128(data):
word = 0
for i, b in enumerate(data):
word |= ((b & 0x7f) << 7*i)
word &= 0xffffffff
if not b & 0x80:
return word, i+1
return word, len(data)
def fromtag(data):
data = data.ljust(4, b'\0')
tag = (data[0] << 8) | data[1]
weight, d = fromleb128(data[2:])
size, d_ = fromleb128(data[2+d:])
return tag>>15, tag&0x7fff, weight, size, 2+d+d_
def frombranch(data):
d = 0
block, d_ = fromleb128(data[d:]); d += d_
trunk, d_ = fromleb128(data[d:]); d += d_
cksum = fromle32(data[d:]); d += 4
return block, trunk, cksum
def xxd(data, width=16):
for i in range(0, len(data), width):
yield '%-*s %-*s' % (
3*width,
' '.join('%02x' % b for b in data[i:i+width]),
width,
''.join(
b if b >= ' ' and b <= '~' else '.'
for b in map(chr, data[i:i+width])))
def tagrepr(tag, w, size, off=None):
if (tag & 0xefff) == TAG_NULL:
return '%snull%s%s' % (
'shrub' if tag & TAG_SHRUB else '',
' w%d' % w if w else '',
' %d' % size if size else '')
elif (tag & 0xef00) == TAG_CONFIG:
return '%s%s%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
'magic' if (tag & 0xfff) == TAG_MAGIC
else 'version' if (tag & 0xfff) == TAG_VERSION
else 'ocompatflags' if (tag & 0xfff) == TAG_OCOMPATFLAGS
else 'rcompatflags' if (tag & 0xfff) == TAG_RCOMPATFLAGS
else 'wcompatflags' if (tag & 0xfff) == TAG_WCOMPATFLAGS
else 'blocksize' if (tag & 0xfff) == TAG_BLOCKSIZE
else 'blockcount' if (tag & 0xfff) == TAG_BLOCKCOUNT
else 'sizelimit' if (tag & 0xfff) == TAG_SIZELIMIT
else 'namelimit' if (tag & 0xfff) == TAG_NAMELIMIT
else 'config 0x%02x' % (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xef00) == TAG_GDELTA:
return '%s%s%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
'grmdelta' if (tag & 0xfff) == TAG_GRMDELTA
else 'gdelta 0x%02x' % (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xef00) == TAG_NAME:
return '%s%s%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
'name' if (tag & 0xfff) == TAG_NAME
else 'reg' if (tag & 0xfff) == TAG_REG
else 'dir' if (tag & 0xfff) == TAG_DIR
else 'scratch' if (tag & 0xfff) == TAG_SCRATCH
else 'bookmark' if (tag & 0xfff) == TAG_BOOKMARK
else 'name 0x%02x' % (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xef00) == TAG_STRUCT:
return '%s%s%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
'data' if (tag & 0xfff) == TAG_DATA
else 'block' if (tag & 0xfff) == TAG_BLOCK
else 'bshrub' if (tag & 0xfff) == TAG_BSHRUB
else 'btree' if (tag & 0xfff) == TAG_BTREE
else 'did' if (tag & 0xfff) == TAG_DID
else 'becksum' if (tag & 0xfff) == TAG_BECKSUM
else 'branch' if (tag & 0xfff) == TAG_BRANCH
else 'mroot' if (tag & 0xfff) == TAG_MROOT
else 'mdir' if (tag & 0xfff) == TAG_MDIR
else 'mtree' if (tag & 0xfff) == TAG_MTREE
else 'struct 0x%02x' % (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xef00) == TAG_UATTR:
return '%suattr 0x%02x%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
((tag & 0x100) >> 1) | (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xef00) == TAG_SATTR:
return '%ssattr 0x%02x%s %d' % (
'shrub' if tag & TAG_SHRUB else '',
((tag & 0x100) >> 1) | (tag & 0xff),
' w%d' % w if w else '',
size)
elif (tag & 0xff00) == TAG_CKSUM:
return 'cksum 0x%02x%s %d' % (
tag & 0xff,
' w%d' % w if w > 0 else '',
size)
elif (tag & 0xff00) == TAG_ECKSUM:
return 'ecksum%s%s %d' % (
' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
' w%d' % w if w > 0 else '',
size)
elif tag & TAG_ALT:
return 'alt%s%s 0x%x w%d %s' % (
'r' if tag & TAG_R else 'b',
'gt' if tag & TAG_GT else 'le',
tag & 0x0fff,
w,
'0x%x' % (0xffffffff & (off-size))
if off is not None
else '-%d' % off)
else:
return '0x%04x w%d %d' % (tag, w, size)
# this type is used for tree representations
TBranch = co.namedtuple('TBranch', 'a, b, d, c')
# our core rbyd type
class Rbyd:
def __init__(self, block, data, rev, eoff, trunk, weight):
self.block = block
self.data = data
self.rev = rev
self.eoff = eoff
self.trunk = trunk
self.weight = weight
self.redund_blocks = []
def addr(self):
if not self.redund_blocks:
return '0x%x.%x' % (self.block, self.trunk)
else:
return '0x{%x,%s}.%x' % (
self.block,
','.join('%x' % block for block in self.redund_blocks),
self.trunk)
@classmethod
def fetch(cls, f, block_size, blocks, trunk=None):
if isinstance(blocks, int):
blocks = [blocks]
if len(blocks) > 1:
# fetch all blocks
rbyds = [cls.fetch(f, block_size, block, trunk) for block in blocks]
# determine most recent revision
i = 0
for i_, rbyd in enumerate(rbyds):
# compare with sequence arithmetic
if rbyd and (
not rbyds[i]
or not ((rbyd.rev - rbyds[i].rev) & 0x80000000)
or (rbyd.rev == rbyds[i].rev
and rbyd.trunk > rbyds[i].trunk)):
i = i_
# keep track of the other blocks
rbyd = rbyds[i]
rbyd.redund_blocks = [rbyds[(i+1+j) % len(rbyds)].block
for j in range(len(rbyds)-1)]
return rbyd
else:
# block may encode a trunk
block = blocks[0]
if isinstance(block, tuple):
if trunk is None:
trunk = block[1]
block = block[0]
# seek to the block
f.seek(block * block_size)
data = f.read(block_size)
# fetch the rbyd
rev = fromle32(data[0:4])
cksum = 0
cksum_ = crc32c(data[0:4])
eoff = 0
j_ = 4
trunk_ = 0
trunk__ = 0
trunk___ = 0
weight = 0
weight_ = 0
weight__ = 0
wastrunk = False
trunkeoff = None
while j_ < len(data) and (not trunk or eoff <= trunk):
v, tag, w, size, d = fromtag(data[j_:])
if v != (popc(cksum_) & 1):
break
cksum_ = crc32c(data[j_:j_+d], cksum_)
j_ += d
if not tag & TAG_ALT and j_ + size > len(data):
break
# take care of cksums
if not tag & TAG_ALT:
if (tag & 0xff00) != TAG_CKSUM:
cksum_ = crc32c(data[j_:j_+size], cksum_)
# found a cksum?
else:
cksum__ = fromle32(data[j_:j_+4])
if cksum_ != cksum__:
break
# commit what we have
eoff = trunkeoff if trunkeoff else j_ + size
cksum = cksum_
trunk_ = trunk__
weight = weight_
# evaluate trunks
if (tag & 0xf000) != TAG_CKSUM and (
not trunk or trunk >= j_-d or wastrunk):
# new trunk?
if not wastrunk:
wastrunk = True
trunk___ = j_-d
weight__ = 0
# keep track of weight
weight__ += w
# end of trunk?
if not tag & TAG_ALT:
wastrunk = False
# update trunk/weight unless we found a shrub or an
# explicit trunk (which may be a shrub) is requested
if not tag & TAG_SHRUB or trunk:
trunk__ = trunk___
weight_ = weight__
# keep track of eoff for best matching trunk
if trunk and j_ + size > trunk:
trunkeoff = j_ + size
cksum = cksum_
trunk_ = trunk__
weight = weight_
if not tag & TAG_ALT:
j_ += size
return cls(block, data, rev, eoff, trunk_, weight)
def lookup(self, rid, tag):
if not self:
return True, 0, -1, 0, 0, 0, b'', []
lower = 0
upper = self.weight
path = []
# descend down tree
j = self.trunk
while True:
_, alt, weight_, jump, d = fromtag(self.data[j:])
# found an alt?
if alt & TAG_ALT:
# follow?
if ((rid, tag & 0xfff) > (upper-weight_-1, alt & 0xfff)
if alt & TAG_GT
else ((rid, tag & 0xfff)
<= (lower+weight_-1, alt & 0xfff))):
lower += upper-lower-weight_ if alt & TAG_GT else 0
upper -= upper-lower-weight_ if not alt & TAG_GT else 0
j = j - jump
# figure out which color
if alt & TAG_R:
_, nalt, _, _, _ = fromtag(self.data[j+jump+d:])
if nalt & TAG_R:
path.append((j+jump, j, True, 'y'))
else:
path.append((j+jump, j, True, 'r'))
else:
path.append((j+jump, j, True, 'b'))
# stay on path
else:
lower += weight_ if not alt & TAG_GT else 0
upper -= weight_ if alt & TAG_GT else 0
j = j + d
# figure out which color
if alt & TAG_R:
_, nalt, _, _, _ = fromtag(self.data[j:])
if nalt & TAG_R:
path.append((j-d, j, False, 'y'))
else:
path.append((j-d, j, False, 'r'))
else:
path.append((j-d, j, False, 'b'))
# found tag
else:
rid_ = upper-1
tag_ = alt
w_ = upper-lower
done = not tag_ or (rid_, tag_) < (rid, tag)
return done, rid_, tag_, w_, j, d, self.data[j+d:j+d+jump], path
def __bool__(self):
return bool(self.trunk)
def __eq__(self, other):
return self.block == other.block and self.trunk == other.trunk
def __ne__(self, other):
return not self.__eq__(other)
def __iter__(self):
tag = 0
rid = -1
while True:
done, rid, tag, w, j, d, data, _ = self.lookup(rid, tag+0x1)
if done:
break
yield rid, tag, w, j, d, data
# create tree representation for debugging
def tree(self):
trunks = co.defaultdict(lambda: (-1, 0))
alts = co.defaultdict(lambda: {})
rid, tag = -1, 0
while True:
done, rid, tag, w, j, d, data, path = self.lookup(rid, tag+0x1)
# found end of tree?
if done:
break
# keep track of trunks/alts
trunks[j] = (rid, tag)
for j_, j__, followed, c in path:
if followed:
alts[j_] |= {'f': j__, 'c': c}
else:
alts[j_] |= {'nf': j__, 'c': c}
# prune any alts with unreachable edges
pruned = {}
for j_, alt in alts.items():
if 'f' not in alt:
pruned[j_] = alt['nf']
elif 'nf' not in alt:
pruned[j_] = alt['f']
for j_ in pruned.keys():
del alts[j_]
for j_, alt in alts.items():
while alt['f'] in pruned:
alt['f'] = pruned[alt['f']]
while alt['nf'] in pruned:
alt['nf'] = pruned[alt['nf']]
# find the trunk and depth of each alt, assuming pruned alts
# didn't exist
def rec_trunk(j_):
if j_ not in alts:
return trunks[j_]
else:
if 'nft' not in alts[j_]:
alts[j_]['nft'] = rec_trunk(alts[j_]['nf'])
return alts[j_]['nft']
for j_ in alts.keys():
rec_trunk(j_)
for j_, alt in alts.items():
if alt['f'] in alts:
alt['ft'] = alts[alt['f']]['nft']
else:
alt['ft'] = trunks[alt['f']]
def rec_height(j_):
if j_ not in alts:
return 0
else:
if 'h' not in alts[j_]:
alts[j_]['h'] = max(
rec_height(alts[j_]['f']),
rec_height(alts[j_]['nf'])) + 1
return alts[j_]['h']
for j_ in alts.keys():
rec_height(j_)
t_depth = max((alt['h']+1 for alt in alts.values()), default=0)
# convert to more general tree representation
tree = set()
for j, alt in alts.items():
# note all non-trunk edges should be black
tree.add(TBranch(
a=alt['nft'],
b=alt['nft'],
d=t_depth-1 - alt['h'],
c=alt['c'],
))
tree.add(TBranch(
a=alt['nft'],
b=alt['ft'],
d=t_depth-1 - alt['h'],
c='b',
))
return tree, t_depth
def main(disk, roots=None, *,
block_size=None,
block_count=None,
trunk=None,
color='auto',
**args):
# figure out what color should be
if color == 'auto':
color = sys.stdout.isatty()
elif color == 'always':
color = True
else:
color = False
# is bd geometry specified?
if isinstance(block_size, tuple):
block_size, block_count_ = block_size
if block_count is None:
block_count = block_count_
# flatten roots, default to block 0
if not roots:
roots = [[0]]
roots = [block for roots_ in roots for block in roots_]
# we seek around a bunch, so just keep the disk open
with open(disk, 'rb') as f:
# if block_size is omitted, assume the block device is one big block
if block_size is None:
f.seek(0, os.SEEK_END)
block_size = f.tell()
# fetch the root
btree = Rbyd.fetch(f, block_size, roots, trunk)
print('btree %s, rev %d, weight %d' % (
btree.addr(), btree.rev, btree.weight))
# look up a bid, while keeping track of the search path
def btree_lookup(bid, *,
depth=None):
rbyd = btree
rid = bid
depth_ = 1
path = []
# corrupted? return a corrupted block once
if not rbyd:
return bid > 0, bid, 0, rbyd, -1, [], path
while True:
# collect all tags, normally you don't need to do this
# but we are debugging here
name = None
tags = []
branch = None
rid_ = rid
tag = 0
w = 0
for i in it.count():
done, rid__, tag, w_, j, d, data, _ = rbyd.lookup(
rid_, tag+0x1)
if done or (i != 0 and rid__ != rid_):
break
# first tag indicates the branch's weight
if i == 0:
rid_, w = rid__, w_
# catch any branches
if tag & 0xfff == TAG_BRANCH:
branch = (tag, j, d, data)
tags.append((tag, j, d, data))
# keep track of path
path.append((bid + (rid_-rid), w, rbyd, rid_, tags))
# descend down branch?
if branch is not None and (
not depth or depth_ < depth):
tag, j, d, data = branch
block, trunk, cksum = frombranch(data)
rbyd = Rbyd.fetch(f, block_size, block, trunk)
# corrupted? bail here so we can keep traversing the tree
if not rbyd:
return False, bid + (rid_-rid), w, rbyd, -1, [], path
rid -= (rid_-(w-1))
depth_ += 1
else:
return not tags, bid + (rid_-rid), w, rbyd, rid_, tags, path
# precompute rbyd-trees if requested
t_width = 0
if args.get('tree'):
# find the max depth of each layer to nicely align trees
bdepths = {}
bid = -1
while True:
done, bid, w, rbyd, rid, tags, path = btree_lookup(
bid+1, depth=args.get('depth'))
if done:
break
for d, (bid, w, rbyd, rid, tags) in enumerate(path):
_, rdepth = rbyd.tree()
bdepths[d] = max(bdepths.get(d, 0), rdepth)
# find all branches
tree = set()
root = None
branches = {}
bid = -1
while True:
done, bid, w, rbyd, rid, tags, path = btree_lookup(
bid+1, depth=args.get('depth'))
if done:
break
d_ = 0
leaf = None
for d, (bid, w, rbyd, rid, tags) in enumerate(path):
if not tags:
continue
# map rbyd tree into B-tree space
rtree, rdepth = rbyd.tree()
# note we adjust our bid/rids to be left-leaning,
# this allows a global order and make tree rendering quite
# a bit easier
rtree_ = set()
for branch in rtree:
a_rid, a_tag = branch.a
b_rid, b_tag = branch.b
_, _, _, a_w, _, _, _, _ = rbyd.lookup(a_rid, 0)
_, _, _, b_w, _, _, _, _ = rbyd.lookup(b_rid, 0)
rtree_.add(TBranch(
a=(a_rid-(a_w-1), a_tag),
b=(b_rid-(b_w-1), b_tag),
d=branch.d,
c=branch.c,
))
rtree = rtree_
# connect our branch to the rbyd's root
if leaf is not None:
root = min(rtree,
key=lambda branch: branch.d,
default=None)
if root is not None:
r_rid, r_tag = root.a
else:
r_rid, r_tag = rid-(w-1), tags[0][0]
tree.add(TBranch(
a=leaf,
b=(bid-rid+r_rid, d, r_rid, r_tag),
d=d_-1,
c='b',
))
for branch in rtree:
# map rbyd branches into our btree space
a_rid, a_tag = branch.a
b_rid, b_tag = branch.b
tree.add(TBranch(
a=(bid-rid+a_rid, d, a_rid, a_tag),
b=(bid-rid+b_rid, d, b_rid, b_tag),
d=branch.d + d_ + bdepths.get(d, 0)-rdepth,
c=branch.c,
))
d_ += max(bdepths.get(d, 0), 1)
leaf = (bid-(w-1), d, rid-(w-1),
next((tag for tag, _, _, _ in tags
if tag & 0xfff == TAG_BRANCH),
TAG_BRANCH))
# remap branches to leaves if we aren't showing inner branches
if not args.get('inner'):
# step through each layer backwards
b_depth = max((branch.b[1]+1 for branch in tree), default=0)
# keep track of the original bids, unfortunately because we
# store the bids in the branches we overwrite these
tree = {(branch.b[0] - branch.b[2], branch) for branch in tree}
for bd in reversed(range(b_depth-1)):
# find leaf-roots at this level
roots = {}
for bid, branch in tree:
# choose the highest node as the root
if (branch.b[1] == b_depth-1
and (bid not in roots
or branch.d < roots[bid].d)):
roots[bid] = branch
# remap branches to leaf-roots
tree_ = set()
for bid, branch in tree:
if branch.a[1] == bd and branch.a[0] in roots:
branch = TBranch(
a=roots[branch.a[0]].b,
b=branch.b,
d=branch.d,
c=branch.c,
)
if branch.b[1] == bd and branch.b[0] in roots:
branch = TBranch(
a=branch.a,
b=roots[branch.b[0]].b,
d=branch.d,
c=branch.c,
)
tree_.add((bid, branch))
tree = tree_
# strip out bids
tree = {branch for _, branch in tree}
# precompute B-trees if requested
elif args.get('btree'):
# find all branches
tree = set()
root = None
branches = {}
bid = -1
while True:
done, bid, w, rbyd, rid, tags, path = btree_lookup(
bid+1, depth=args.get('depth'))
if done:
break
# if we're not showing inner nodes, prefer names higher in
# the tree since this avoids showing vestigial names
name = None
if not args.get('inner'):
name = None
for bid_, w_, rbyd_, rid_, tags_ in reversed(path):
for tag_, j_, d_, data_ in tags_:
if tag_ & 0x7f00 == TAG_NAME:
name = (tag_, j_, d_, data_)
if rid_-(w_-1) != 0:
break
a = root
for d, (bid, w, rbyd, rid, tags) in enumerate(path):
if not tags:
continue
b = (bid-(w-1), d, rid-(w-1),
(name if name else tags[0])[0])
# remap branches to leaves if we aren't showing
# inner branches
if not args.get('inner'):
if b not in branches:
bid, w, rbyd, rid, tags = path[-1]
if not tags:
continue
branches[b] = (
bid-(w-1), len(path)-1, rid-(w-1),
(name if name else tags[0])[0])
b = branches[b]
# found entry point?
if root is None:
root = b
a = root
tree.add(TBranch(
a=a,
b=b,
d=d,
c='b',
))
a = b
# common tree renderer
if args.get('tree') or args.get('btree'):
# find the max depth from the tree
t_depth = max((branch.d+1 for branch in tree), default=0)
if t_depth > 0:
t_width = 2*t_depth + 2
def treerepr(bid, w, bd, rid, tag):
if t_depth == 0:
return ''
def branchrepr(x, d, was):
for branch in tree:
if branch.d == d and branch.b == x:
if any(branch.d == d and branch.a == x
for branch in tree):
return '+-', branch.c, branch.c
elif any(branch.d == d
and x > min(branch.a, branch.b)
and x < max(branch.a, branch.b)
for branch in tree):
return '|-', branch.c, branch.c
elif branch.a < branch.b:
return '\'-', branch.c, branch.c
else:
return '.-', branch.c, branch.c
for branch in tree:
if branch.d == d and branch.a == x:
return '+ ', branch.c, None
for branch in tree:
if (branch.d == d
and x > min(branch.a, branch.b)
and x < max(branch.a, branch.b)):
return '| ', branch.c, was
if was:
return '--', was, was
return ' ', None, None
trunk = []
was = None
for d in range(t_depth):
t, c, was = branchrepr(
(bid-(w-1), bd, rid-(w-1), tag), d, was)
trunk.append('%s%s%s%s' % (
'\x1b[33m' if color and c == 'y'
else '\x1b[31m' if color and c == 'r'
else '\x1b[90m' if color and c == 'b'
else '',
t,
('>' if was else ' ') if d == t_depth-1 else '',
'\x1b[m' if color and c else ''))
return '%s ' % ''.join(trunk)
# dynamically size the id field
w_width = m.ceil(m.log10(max(1, btree.weight)+1))
# prbyd here means the last rendered rbyd, we update
# in dbg_branch to always print interleaved addresses
prbyd = None
def dbg_branch(bid, w, rbyd, rid, tags, bd):
nonlocal prbyd
# show human-readable representation
for i, (tag, j, d, data) in enumerate(tags):
print('%10s %s%*s %-*s %s' % (
'%04x.%04x:' % (rbyd.block, rbyd.trunk)
if prbyd is None or rbyd != prbyd
else '',
treerepr(bid, w, bd, rid, tag)
if args.get('tree') or args.get('btree') else '',
2*w_width+1, '' if i != 0
else '%d-%d' % (bid-(w-1), bid) if w > 1
else bid if w > 0
else '',
21+w_width, tagrepr(
tag, w if i == 0 else 0, len(data), None),
next(xxd(data, 8), '')
if not args.get('raw') and not args.get('no_truncate')
else ''))
prbyd = rbyd
# show in-device representation
if args.get('device'):
print('%9s %*s%*s %04x %08x %07x' % (
'',
t_width, '',
2*w_width+1, '',
tag, w if i == 0 else 0, len(data)))
# show on-disk encoding of tags/data
if args.get('raw'):
for o, line in enumerate(xxd(rbyd.data[j:j+d])):
print('%9s: %*s%*s %s' % (
'%04x' % (j + o*16),
t_width, '',
2*w_width+1, '',
line))
if args.get('raw') or args.get('no_truncate'):
for o, line in enumerate(xxd(data)):
print('%9s: %*s%*s %s' % (
'%04x' % (j+d + o*16),
t_width, '',
2*w_width+1, '',
line))
# traverse and print entries
bid = -1
prbyd = None
ppath = []
corrupted = False
while True:
done, bid, w, rbyd, rid, tags, path = btree_lookup(
bid+1, depth=args.get('depth'))
if done:
break
# print inner btree entries if requested
if args.get('inner'):
changed = False
for (x, px) in it.zip_longest(
enumerate(path[:-1]),
enumerate(ppath[:-1])):
if x is None:
break
if not (changed or px is None or x != px):
continue
changed = True
# show the inner entry
d, (bid_, w_, rbyd_, rid_, tags_) = x
dbg_branch(bid_, w_, rbyd_, rid_, tags_, d)
ppath = path
# corrupted? try to keep printing the tree
if not rbyd:
print('%04x.%04x: %*s%s%s%s' % (
rbyd.block, rbyd.trunk,
t_width, '',
'\x1b[31m' if color else '',
'(corrupted rbyd %s)' % rbyd.addr(),
'\x1b[m' if color else ''))
prbyd = rbyd
corrupted = True
continue
# if we're not showing inner nodes, prefer names higher in the tree
# since this avoids showing vestigial names
if not args.get('inner'):
name = None
for bid_, w_, rbyd_, rid_, tags_ in reversed(path):
for tag_, j_, d_, data_ in tags_:
if tag_ & 0x7f00 == TAG_NAME:
name = (tag_, j_, d_, data_)
if rid_-(w_-1) != 0:
break
if name is not None:
tags = [name] + [(tag, j, d, data)
for tag, j, d, data in tags
if tag & 0x7f00 != TAG_NAME]
# show the branch
dbg_branch(bid, w, rbyd, rid, tags, len(path)-1)
if args.get('error_on_corrupt') and corrupted:
sys.exit(2)
if __name__ == "__main__":
import argparse
import sys
parser = argparse.ArgumentParser(
description="Debug rbyd B-trees.",
allow_abbrev=False)
parser.add_argument(
'disk',
help="File containing the block device.")
parser.add_argument(
'roots',
nargs='*',
type=rbydaddr,
help="Block address of the roots of the tree.")
parser.add_argument(
'-B', '--block-size',
type=bdgeom,
help="Block size/geometry in bytes.")
parser.add_argument(
'--block-count',
type=lambda x: int(x, 0),
help="Block count in blocks.")
parser.add_argument(
'--trunk',
type=lambda x: int(x, 0),
help="Use this offset as the trunk of the tree.")
parser.add_argument(
'--color',
choices=['never', 'always', 'auto'],
default='auto',
help="When to use terminal colors. Defaults to 'auto'.")
parser.add_argument(
'-r', '--raw',
action='store_true',
help="Show the raw data including tag encodings.")
parser.add_argument(
'-x', '--device',
action='store_true',
help="Show the device-side representation of tags.")
parser.add_argument(
'-T', '--no-truncate',
action='store_true',
help="Don't truncate, show the full contents.")
parser.add_argument(
'-t', '--tree',
action='store_true',
help="Show the underlying rbyd trees.")
parser.add_argument(
'-b', '--btree',
action='store_true',
help="Show the underlying B-tree.")
parser.add_argument(
'-i', '--inner',
action='store_true',
help="Show inner branches.")
parser.add_argument(
'-Z', '--depth',
nargs='?',
type=lambda x: int(x, 0),
const=0,
help="Depth of tree to show.")
parser.add_argument(
'-e', '--error-on-corrupt',
action='store_true',
help="Error if B-tree is corrupt.")
sys.exit(main(**{k: v
for k, v in vars(parser.parse_intermixed_args()).items()
if v is not None}))
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