Files
littlefs/scripts/dbgmtree.py
Christopher Haster abe68c0844 rbyd-rr: Reworking rbyd range removal to try to preserve rby structure
This is the start of (yet another) rework of rybd range removals, this
time in an effort to preserve the rby structure that maps to a balanced
2-3-4 tree. Specifically, the property that all search paths have the
same number of black edges (2-3-4 nodes).

This is currently incomplete, as you can probably tell from the mess,
but this commit at least gets a working altn/alta encoding in place
necessary for representing empty 2-3-4 nodes. More on that below.

---

First the problem:

My assumption, when implementing the previous range removal algorithms,
was that we only needed to maintain the existing height of the tree.

The existing rbyd operations limit the height to strictly log n. And
while we can't _reduce_ the height to maintain perfect balance, we can
at least avoid _increasing_ the height, which means the resulting tree
should have a height <= log n. Since our rbyds are bounded by the
block_size b, this means worst case our rbyd can never exceed a height
<= log b, right?

Well, not quite.

This is true the instance after the remove operation. But there is an
implicit assumption that future rbyd operations will still be able to
maintain height <= log n after the remove operation. This turns out to
not be true.

The problem is that our rbyd appends only maintain height <= log n if
our rby structure is preserved. If the rby structure is broken, rbyd
append assumes an rby structure that doesn't exist, which can lead to an
increasingly unbalanced tree.

Consider this happily balanced tree:

         .-------o-------.                    .--------o
     .---o---.       .---o---.            .---o---.    |
   .-o-.   .-o-.   .-o-.   .-o-.        .-o-.   .-o-.  |
  .o. .o. .o. .o. .o. .o. .o. .o.      .o. .o. .o. .o. |
  a b c d e f g h i j k l m n o p  =>  a b c d e f g h i
                   '------+------'
                        remove

After a range removal it looks pretty bad, but note the height is still
<= log n (old n not the new n). We are still <= log b.

But note what happens if we start to insert attrs into the short half of
the tree:

         .--------o
     .---o---.    |
   .-o-.   .-o-.  |
  .o. .o. .o. .o. |
  a b c d e f g h i

                  .-----o
         .--------o .-+-r
     .---o---.    | | | |
   .-o-.   .-o-.  | | | |
  .o. .o. .o. .o. | | | |
  a b c d e f g h i j'k'l'

                      .-------------o
                  .---o   .---+-----r
         .--------o .-o .-o .-o .-+-r
     .---o---.    | | | | | | | | | |
   .-o-.   .-o-.  | | | | | | | | | |
  .o. .o. .o. .o. | | | | | | | | | |
  a b c d e f g h i j'k'l'm'n'o'p'q'r'

Our right side is generating a perfectly balanced tree as expected, but
the left side is suddenly twice as far from the root! height(r')=3,
height(a)=6!

The problem is when we append l', we don't really know how tall the tree
is. We only know l' has one black edge, which assuming rby structure is
preserved, means all other attrs must have one black edge, so creating a
new root is justified.

In reality this just makes the tree grow increasingly unbalanced,
increasing the height of the tree by worst case log n every range
removal.

---

It's interesting to note this was discovered while debugging
test_fwrite_overwrite, specifically:

  test_fwrite_overwrite:1181h1g2i1gg2l15o10p11r1gg8s10

It turns out the append fragments -> delete fragments -> append/carve
block + becksum loop contains the perfect sequence of attrs necessary to
turn this tree inbalance into a linked-list!

                        .->         0 data w1 1
                      .-b->         1 data w1 1
                      | .->         2 data w1 1
                    .-b-b->         3 data w1 1
                    |   .->         4 data w1 1
                    | .-b->         5 data w1 1
                    | | .->         6 data w1 1
                .---b-b-b->         7 data w1 1
                |       .->         8 data w1 1
                |     .-b->         9 data w1 1
                |     | .->        10 data w1 1
                |   .-b-b->        11 data w1 1
                | .-b----->        12 data w1 1
              .-y-y------->        13 data w1 1
              |         .->        14 data w1 1
            .-y---------y->        15 data w1 1
            |           .->        16 data w1 1
          .-y-----------y->        17 data w1 1
          |             .->        18 data w1 1
        .-y-------------y->        19 data w1 1
        |               .->        20 data w1 1
      .-y---------------y->        21 data w1 1
      |                 .->        22 data w1 1
    .-y-----------------y->        23 data w1 1
    |                   .->        24 data w1 1
  .-y-------------------y->        25 data w1 1
  |                   .--->        26 data w1 1
  |                   | .->   27-2047 block w2021 10
  b-------------------r-b->           becksum 5

Note, to reproduce this you need to step through with a breakpoint on
lfsr_bshrub_commit. This only shows up in the file's intermediary btree,
which at the time of writing ends up at block 0xb8:

  $ ./scripts/test.py \
        test_fwrite_overwrite:1181h1g2i1gg2l15o10p11r1gg8s10 \
        -ddisk --gdb -f

  $ ./scripts/watch.py -Kdisk -b \
        ./scripts/dbgrbyd.py -b4096 disk 0xb8 -t

  (then b lfsr_bshrub_commit and continue a bunch)

---

So, we need to preserve the rby structure.

Note pruning red/yellow alts is not an issue. These aren't black, so we
aren't changing the number of black edges in the tree. We've just
effectively reduced a 3/4 node into a 2/3 node:

      .-> a
  .---b-> b              .-> a <- 2 black
  | .---> c            .-b-> b
  | | .-> d            | .-> c
  b-r-b-> e <- rm  =>  b-b-> d <- 2 black

The tricky bit is pruning black alts. Naively this changes the number of
black edges/2-3-4 nodes in the tree, which is bad:

    .-> a
  .-b-> b              .-> a <- 2 black
  | .-> c            .-b-> b
  b-b-> d <- rm  =>  b---> c <- 1 black

It's tempting to just make the alt red at this point, effectively
merging the sibling 2-3-4 node. This maintains balance in the subtree,
but still removes a black edge, causing problems for our parent:

      .-> a
    .-b-> b                .-> a <- 3 black
    | .-> c              .-b-> b
  .-b-b-> d              | .-> c
  |   .-> e            .-b-b-> d
  | .-b-> f            | .---> e
  | | .-> g            | | .-> f
  b-b-b-> h <- rm  =>  b-r-b-> g <- 2 black

In theory you could propagate this all the way up to the root, and this
_would_ probably give you a perfect self-balancing range removal
algorithm... but it's recursive... and littlefs can't be recursive...

               .-> s
             .-b-> t                              .-> s
             | .-> u                        .-----b-> t
           .-b-b-> v                        |     .-> u
           |   .-> w                        | .---b-> v
           | .-b-> x                        | | .---> w
  | |      | | .-> y           | | | |      | | | .-> x
  b-b- ... b-b-b-> z <- rm =>  r-b-r-b- ... r-b-r-b-> y

So instead, an alternative solution. What if we allowed black alts that
point nowhere? A sort of noop 2-3-4 node that serves only to maintain
the rby structure?

    .-> a
  .-b-> b              .-> a <- 2 black
  | .-> c            .-b-> b
  b-b-> d <- rm  =>  b-b-> c <- 2 black

I guess that would technically make this 1-2-3-4 tree.

This does add extra overhead for writing noop alts, which are otherwise
useless, but it seems to solve most of our problems: 1. does not
increase the height of the tree, 2. maintains the rby structure, 3.
tail-recursive.

And, thanks to the preserved rby structure, we can say that in the worst
case our rbyds will never exceed height <= log b again, even with range
removals.

If we apply this strategy to our original example, you can see how the
preserved rby structure sort of "absorbs" new red alts, preventing
further unbalancing:

         .-------o-------.                    .--------o
     .---o---.       .---o---.            .---o---.    o
   .-o-.   .-o-.   .-o-.   .-o-.        .-o-.   .-o-.  o
  .o. .o. .o. .o. .o. .o. .o. .o.      .o. .o. .o. .o. o
  a b c d e f g h i j k l m n o p  =>  a b c d e f g h i
                   '------+------'
                        remove

Reinserting:

         .--------o
     .---o---.    o
   .-o-.   .-o-.  o
  .o. .o. .o. .o. o
  a b c d e f g h i

         .----------------o
     .---o---.            o
   .-o-.   .-o-.   .------o
  .o. .o. .o. .o. .o. .-+-r
  a b c d e f g h i j'k'l'm'

         .----------------------------o
     .---o---.          .-------------o
   .-o-.   .-o-.    .---o   .---+-----r
  .o. .o. .o. .o. .-o .-o .-o .-o .-+-r
  a b c d e f g h i j'k'l'm'n'o'p'q'r's'

Much better!

---

This commit makes some big steps towards this solution, mainly codifying
a now-special alt-never/alt-always (altn/alta) encoding to represent
these noop 1 nodes.

Technically, since null (0) tags are not allowed, these already exist as
altle 0/altgt 0 and don't need any extra carve-out encoding-wise:

  LFSR_TAG_ALT   0x4kkk  v1dc kkkk -kkk kkkk
  LFSR_TAG_ALTN  0x4000  v10c 0000 -000 0000
  LFSR_TAG_ALTA  0x6000  v11c 0000 -000 0000

We actually already used altas to terminate unreachable tags during
range removals, but this behavior was implicit. Now, altns have very
special treatment as a part of determining bounds during appendattr
(both unreachable gt/le alts are represented as altns). For this reason
I think the new names are warranted.

I've also added these encodings to the dbg*.py scripts for, well,
debuggability, and added a special case to dbgrby.py -j to avoid
unnecessary altn jump noise.

As a part of debugging, I've also extended dbgrbyd.py's tree renderer to
show trivial prunable alts. Unsure about keeping this. On one hand it's
useful to visualize the exact alt structure, on the other hand it likely
adds quite a bit of noise to the more complex dbg scripts.

The current state of things is a mess, but at least tests are passing!

Though we aren't actually reclaiming any altns yet... We're definitely
_not_ preserving the rby structure at the moment, and if you look at the
output from the tests, the resulting tree structure is hilarious bad.

But at least the path forward is clear.
2024-04-01 16:23:14 -05:00

1706 lines
61 KiB
Python
Executable File

#!/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_RCOMPAT = 0x0005
TAG_WCOMPAT = 0x0006
TAG_OCOMPAT = 0x0007
TAG_GEOMETRY = 0x0009
TAG_NAMELIMIT = 0x000c
TAG_SIZELIMIT = 0x000d
TAG_GDELTA = 0x0100
TAG_GRMDELTA = 0x0100
TAG_NAME = 0x0200
TAG_REG = 0x0201
TAG_DIR = 0x0202
TAG_ORPHAN = 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 frommdir(data):
blocks = []
d = 0
while d < len(data):
block, d_ = fromleb128(data[d:])
blocks.append(block)
d += d_
return blocks
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 frombtree(data):
d = 0
w, d_ = fromleb128(data[d:]); d += d_
block, trunk, cksum = frombranch(data[d:])
return w, 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 'rcompat' if (tag & 0xfff) == TAG_RCOMPAT
else 'wcompat' if (tag & 0xfff) == TAG_WCOMPAT
else 'ocompat' if (tag & 0xfff) == TAG_OCOMPAT
else 'geometry' if (tag & 0xfff) == TAG_GEOMETRY
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 'orphan' if (tag & 0xfff) == TAG_ORPHAN
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%s w%d %s' % (
'r' if tag & TAG_R else 'b',
'a' if tag & 0x0fff == 0 and tag & TAG_GT
else 'n' if tag & 0x0fff == 0
else 'gt' if tag & TAG_GT
else 'le',
' 0x%x' % (tag & 0x0fff) if tag & 0x0fff != 0 else '',
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
eoff = trunkeoff
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'', []
tag = max(tag, 0x1)
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}
# treat unreachable alts as converging paths
for j_, alt in alts.items():
if 'f' not in alt:
alt['f'] = alt['nf']
elif 'nf' not in alt:
alt['nf'] = alt['f']
# find the trunk and depth of each alt
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
# btree lookup with this rbyd as the root
def btree_lookup(self, f, block_size, bid, *,
depth=None):
rbyd = self
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
# btree rbyd-tree generation for debugging
def btree_tree(self, f, block_size, *,
depth=None,
inner=False):
# find the max depth of each layer to nicely align trees
bdepths = {}
bid = -1
while True:
done, bid, w, rbyd, rid, tags, path = self.btree_lookup(
f, block_size, bid+1, depth=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 = self.btree_lookup(
f, block_size, bid+1, depth=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 inner:
# step through each layer backwards
b_depth = max((branch.a[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}
return tree, max((branch.d+1 for branch in tree), default=0)
# btree B-tree generation for debugging
def btree_btree(self, f, block_size, *,
depth=None,
inner=False):
# find all branches
tree = set()
root = None
branches = {}
bid = -1
while True:
done, bid, w, rbyd, rid, tags, path = self.btree_lookup(
f, block_size, bid+1, depth=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 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 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
return tree, max((branch.d+1 for branch in tree), default=0)
def main(disk, mroots=None, *,
block_size=None,
block_count=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 mroots, default to 0x{0,1}
if not mroots:
mroots = [[0,1]]
mroots = [block for mroots_ in mroots for block in mroots_]
# 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()
# determine the mleaf_weight from the block_size, this is just for
# printing purposes
mleaf_weight = 1 << m.ceil(m.log2(block_size // 8))
# before we print, we need to do a pass for a few things:
# - find the actual mroot
# - find the total weight
bweight = 0
rweight = 0
mroot = Rbyd.fetch(f, block_size, mroots)
mdepth = 1
while True:
# corrupted?
if not mroot:
break
rweight = max(rweight, mroot.weight)
# stop here?
if args.get('depth') and mdepth >= args.get('depth'):
break
# fetch the next mroot
done, rid, tag, w, j, d, data, _ = mroot.lookup(-1, TAG_MROOT)
if not (not done and rid == -1 and tag == TAG_MROOT):
break
blocks = frommdir(data)
mroot = Rbyd.fetch(f, block_size, blocks)
mdepth += 1
# fetch the mdir, if there is one
mdir = None
if not args.get('depth') or mdepth < args.get('depth'):
done, rid, tag, w, j, _, data, _ = mroot.lookup(-1, TAG_MDIR)
if not done and rid == -1 and tag == TAG_MDIR:
blocks = frommdir(data)
mdir = Rbyd.fetch(f, block_size, blocks)
# corrupted?
if mdir:
rweight = max(rweight, mdir.weight)
# fetch the actual mtree, if there is one
mtree = None
if not args.get('depth') or mdepth < args.get('depth'):
done, rid, tag, w, j, d, data, _ = mroot.lookup(-1, TAG_MTREE)
if not done and rid == -1 and tag == TAG_MTREE:
w, block, trunk, cksum = frombtree(data)
mtree = Rbyd.fetch(f, block_size, block, trunk)
bweight = w
# traverse entries
mbid = -1
while True:
done, mbid, mw, rbyd, rid, tags, path = mtree.btree_lookup(
f, block_size, mbid+1,
depth=args.get('depth', mdepth)-mdepth)
if done:
break
# corrupted?
if not rbyd:
continue
mdir__ = None
if (not args.get('depth')
or mdepth+len(path) < args.get('depth')):
mdir__ = next(((tag, j, d, data)
for tag, j, d, data in tags
if tag == TAG_MDIR),
None)
if mdir__:
# fetch the mdir
_, _, _, data = mdir__
blocks = frommdir(data)
mdir_ = Rbyd.fetch(f, block_size, blocks)
# corrupted?
if mdir_:
rweight = max(rweight, mdir_.weight)
# precompute rbyd-tree if requested
t_width = 0
if args.get('tree'):
# compute mroot chain "tree", prefix our actual mtree with this
tree = set()
d_ = 0
mroot_ = Rbyd.fetch(f, block_size, mroots)
mdepth_ = 1
for d in it.count():
# corrupted?
if not mroot_:
break
# compute the mroots rbyd-tree
rtree, rdepth = mroot_.tree()
# connect branch to our root
if d > 0:
root = min(rtree,
key=lambda branch: branch.d,
default=None)
if root:
r_rid, r_tag = root.a
else:
_, r_rid, r_tag, _, _, _, _, _ = mroot_.lookup(-1, 0x1)
tree.add(TBranch(
a=(-1, d-1, 0, -1, TAG_MROOT),
b=(-1, d, 0, r_rid, r_tag),
d=d_-1,
c='b',
))
# map the tree into our metadata space
for branch in rtree:
a_rid, a_tag = branch.a
b_rid, b_tag = branch.b
tree.add(TBranch(
a=(-1, d, 0, a_rid, a_tag),
b=(-1, d, 0, b_rid, b_tag),
d=d_ + branch.d,
c=branch.c,
))
d_ += rdepth
# stop here?
if args.get('depth') and mdepth_ >= args.get('depth'):
break
# fetch the next mroot
done, rid, tag, w, j, _, data, _ = mroot_.lookup(-1, TAG_MROOT)
if not (not done and rid == -1 and tag == TAG_MROOT):
break
blocks = frommdir(data)
mroot_ = Rbyd.fetch(f, block_size, blocks)
mdepth_ += 1
# compute mdir's rbyd-tree if there is one
if mdir:
rtree, rdepth = mdir.tree()
# connect branch to our root
root = min(rtree,
key=lambda branch: branch.d,
default=None)
if root:
r_rid, r_tag = root.a
else:
_, r_rid, r_tag, _, _, _, _, _ = mdir.lookup(-1, 0x1)
tree.add(TBranch(
a=(-1, d, 0, -1, TAG_MDIR),
b=(0, 0, 0, r_rid, r_tag),
d=d_-1,
c='b',
))
# map the tree into our metadata space
for branch in rtree:
a_rid, a_tag = branch.a
b_rid, b_tag = branch.b
tree.add(TBranch(
a=(0, 0, 0, a_rid, a_tag),
b=(0, 0, 0, b_rid, b_tag),
d=d_ + branch.d,
c=branch.c,
))
# compute the mtree's rbyd-tree if there is one
if mtree:
tree_, tdepth = mtree.btree_tree(
f, block_size,
depth=args.get('depth', mdepth)-mdepth,
inner=args.get('inner'))
# connect a branch to the root of the tree
root = min(tree_, key=lambda branch: branch.d, default=None)
if root:
r_bid, r_bd, r_rid, r_tag = root.a
tree.add(TBranch(
a=(-1, d, 0, -1, TAG_MTREE),
b=(r_bid, r_bd, r_rid, 0, r_tag),
d=d_-1,
c='b',
))
# map the tree into our metadata space
for branch in tree_:
a_bid, a_bd, a_rid, a_tag = branch.a
b_bid, b_bd, b_rid, b_tag = branch.b
tree.add(TBranch(
a=(a_bid, a_bd, a_rid, 0, a_tag),
b=(b_bid, b_bd, b_rid, 0, b_tag),
d=d_ + branch.d,
c=branch.c,
))
# find the max depth of each mdir to nicely align trees
mdepth_ = 0
mbid = -1
while True:
done, mbid, mw, rbyd, rid, tags, path = mtree.btree_lookup(
f, block_size, mbid+1,
depth=args.get('depth', mdepth)-mdepth)
if done:
break
# corrupted?
if not rbyd:
continue
mdir__ = None
if (not args.get('depth')
or mdepth+len(path) < args.get('depth')):
mdir__ = next(((tag, j, d, data)
for tag, j, d, data in tags
if tag == TAG_MDIR),
None)
if mdir__:
# fetch the mdir
_, _, _, data = mdir__
blocks = frommdir(data)
mdir_ = Rbyd.fetch(f, block_size, blocks)
rtree, rdepth = mdir_.tree()
mdepth_ = max(mdepth_, rdepth)
# compute the rbyd-tree for each mdir
mbid = -1
while True:
done, mbid, mw, rbyd, rid, tags, path = mtree.btree_lookup(
f, block_size, mbid+1,
depth=args.get('depth', mdepth)-mdepth)
if done:
break
# corrupted?
if not rbyd:
continue
mdir__ = None
if (not args.get('depth')
or mdepth+len(path) < args.get('depth')):
mdir__ = next(((tag, j, d, data)
for tag, j, d, data in tags
if tag == TAG_MDIR),
None)
if mdir__:
# fetch the mdir
_, _, _, data = mdir__
blocks = frommdir(data)
mdir_ = Rbyd.fetch(f, block_size, blocks)
rtree, rdepth = mdir_.tree()
# connect the root to the mtree
branch = max(
(branch for branch in tree
if branch.b[0] == mbid-(mw-1)),
key=lambda branch: branch.d,
default=None)
if branch:
root = min(rtree,
key=lambda branch: branch.d,
default=None)
if root:
r_rid, r_tag = root.a
else:
_, r_rid, r_tag, _, _, _, _, _ = (
mdir_.lookup(-1, 0x1))
tree.add(TBranch(
a=branch.b,
b=(mbid-(mw-1), len(path), 0, r_rid, r_tag),
d=d_ + tdepth,
c='b',
))
# map the tree into our metadata space
for branch in rtree:
a_rid, a_tag = branch.a
b_rid, b_tag = branch.b
tree.add(TBranch(
a=(mbid-(mw-1), len(path), 0, a_rid, a_tag),
b=(mbid-(mw-1), len(path), 0, b_rid, b_tag),
d=(d_ + tdepth + 1
+ branch.d + mdepth_-rdepth),
c=branch.c,
))
# 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:
# note we ignore mroot branches, we don't collapse
# normally these
if (branch.a[0] != -1
and 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[0] != -1
and 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-tree if requested
elif args.get('btree'):
# compute mroot chain "tree", prefix our actual mtree with this
tree = set()
mroot_ = Rbyd.fetch(f, block_size, mroots)
mdepth_ = 1
for d in it.count():
# corrupted?
if not mroot_:
break
# connect branch to our first tag
if d > 0:
done, rid, tag, w, j, _, data, _ = mroot_.lookup(-1, 0x1)
if not done:
tree.add(TBranch(
a=(-1, d-1, 0, -1, TAG_MROOT),
b=(-1, d, 0, rid, tag),
d=0,
c='b',
))
# stop here?
if args.get('depth') and mdepth_ >= args.get('depth'):
break
# fetch the next mroot
done, rid, tag, w, j, _, data, _ = mroot_.lookup(-1, TAG_MROOT)
if not (not done and rid == -1 and tag == TAG_MROOT):
break
blocks = frommdir(data)
mroot_ = Rbyd.fetch(f, block_size, blocks)
mdepth_ += 1
# create a branch to our mdir if there is one
if mdir:
# connect branch to our first tag
done, rid, tag, w, j, _, data, _ = mdir.lookup(-1, 0x1)
if not done:
tree.add(TBranch(
a=(-1, d, 0, -1, TAG_MDIR),
b=(0, 0, 0, rid, tag),
d=0,
c='b',
))
# compute the mtree's B-tree if there is one
if mtree:
tree_, tdepth = mtree.btree_btree(
f, block_size,
depth=args.get('depth', mdepth)-mdepth,
inner=args.get('inner'))
# connect a branch to the root of the tree
root = min(tree_, key=lambda branch: branch.d, default=None)
if root:
r_bid, r_bd, r_rid, r_tag = root.a
tree.add(TBranch(
a=(-1, d, 0, -1, TAG_MTREE),
b=(r_bid, r_bd, r_rid, 0, r_tag),
d=0,
c='b',
))
# map the tree into our metadata space
for branch in tree_:
a_bid, a_bd, a_rid, a_tag = branch.a
b_bid, b_bd, b_rid, b_tag = branch.b
tree.add(TBranch(
a=(a_bid, a_bd, a_rid, 0, a_tag),
b=(b_bid, b_bd, b_rid, 0, b_tag),
d=1 + branch.d,
c=branch.c,
))
# remap branches to leaves if we aren't showing inner branches
if not args.get('inner'):
mbid = -1
while True:
done, mbid, mw, rbyd, rid, tags, path = (
mtree.btree_lookup(
f, block_size, mbid+1,
depth=args.get('depth', mdepth)-mdepth))
if done:
break
# corrupted?
if not rbyd:
continue
mdir__ = None
if (not args.get('depth')
or mdepth+len(path) < args.get('depth')):
mdir__ = next(((tag, j, d, data)
for tag, j, d, data in tags
if tag == TAG_MDIR),
None)
if mdir__:
# fetch the mdir
_, _, _, data = mdir__
blocks = frommdir(data)
mdir_ = Rbyd.fetch(f, block_size, blocks)
# find the first entry in the mdir, map branches
# to this entry
done, rid, tag, _, j, d, data, _ = (
mdir_.lookup(-1, 0x1))
tree_ = set()
for branch in tree:
if branch.a[0] == mbid-(mw-1):
a_bid, a_bd, _, _, _ = branch.a
branch = TBranch(
a=(a_bid, a_bd+1, 0, rid, tag),
b=branch.b,
d=branch.d,
c=branch.c,
)
if branch.b[0] == mbid-(mw-1):
b_bid, b_bd, _, _, _ = branch.b
branch = TBranch(
a=branch.a,
b=(b_bid, b_bd+1, 0, rid, tag),
d=branch.d,
c=branch.c,
)
tree_.add(branch)
tree = tree_
# 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(mbid, mw, md, mrid, 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(
(mbid-max(mw-1, 0), md, mrid-max(mw-1, 0), rid, 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)
def dbg_mdir(mdir, mbid, mw, md):
for i, (rid, tag, w, j, d, data) in enumerate(mdir):
# show human-readable tag representation
print('%12s %s%s' % (
'{%s}:' % ','.join('%04x' % block
for block in it.chain([mdir.block],
mdir.redund_blocks))
if i == 0 else '',
treerepr(mbid-max(mw-1, 0), 0, md, 0, rid, tag)
if args.get('tree') or args.get('btree') else '',
'%*s %-*s%s' % (
2*w_width+1, '%d.%d-%d' % (
mbid//mleaf_weight, rid-(w-1), rid)
if w > 1 else '%d.%d' % (mbid//mleaf_weight, rid)
if w > 0 or i == 0 else '',
21+w_width, tagrepr(tag, w, len(data), j),
' %s' % next(xxd(data, 8), '')
if not args.get('raw')
and not args.get('no_truncate')
else '')))
# show in-device representation
if args.get('device'):
print('%11s %*s%*s %04x %08x %07x' % (
'',
t_width, '',
2*w_width+1, '',
tag, w, len(data)));
# show on-disk encoding of tags
if args.get('raw'):
for o, line in enumerate(xxd(mdir.data[j:j+d])):
print('%11s: %*s%*s %s' % (
'%04x' % (j + o*16),
t_width, '',
2*w_width+1, '',
line))
if args.get('raw') or args.get('no_truncate'):
if not tag & TAG_ALT:
for o, line in enumerate(xxd(data)):
print('%11s: %*s%*s %s' % (
'%04x' % (j+d + o*16),
t_width, '',
2*w_width+1, '',
line))
# 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('%12s %s%*s %-*s %s' % (
'%04x.%04x:' % (rbyd.block, rbyd.trunk)
if prbyd is None or rbyd != prbyd
else '',
treerepr(bid, w, bd, rid, 0, tag)
if args.get('tree') or args.get('btree') else '',
2*w_width+1, '' if i != 0
else '%d-%d' % (
(bid-(w-1))//mleaf_weight,
bid//mleaf_weight)
if (w//mleaf_weight) > 1
else bid//mleaf_weight 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('%11s %*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('%11s: %*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('%11s: %*s%*s %s' % (
'%04x' % (j+d + o*16),
t_width, '',
2*w_width+1, '',
line))
#### actual debugging begins here
# print some information about the mtree
print('mtree %s, rev %d, weight %d.%d' % (
mroot.addr(), mroot.rev, bweight//mleaf_weight, 1*mleaf_weight))
# dynamically size the id field
w_width = max(
m.ceil(m.log10(max(1, bweight//mleaf_weight)+1)),
m.ceil(m.log10(max(1, rweight)+1)),
# in case of -1.-1
2)
# show each mroot
prbyd = None
ppath = []
corrupted = False
mroot = Rbyd.fetch(f, block_size, mroots)
mdepth = 1
for d in it.count():
# corrupted?
if not mroot:
print('{%s}: %s%s%s' % (
','.join('%04x' % block
for block in it.chain([mroot.block],
mroot.redund_blocks)),
'\x1b[31m' if color else '',
'(corrupted mroot %s)' % mroot.addr(),
'\x1b[m' if color else ''))
corrupted = True
break
else:
# show the mdir
dbg_mdir(mroot, -1, 0, d)
# stop here?
if args.get('depth') and mdepth >= args.get('depth'):
break
# fetch the next mroot
done, rid, tag, w, j, _, data, _ = mroot.lookup(-1, TAG_MROOT)
if not (not done and rid == -1 and tag == TAG_MROOT):
break
blocks = frommdir(data)
mroot = Rbyd.fetch(f, block_size, blocks)
mdepth += 1
# show the mdir, if there is one
if not args.get('depth') or mdepth < args.get('depth'):
done, rid, tag, w, j, _, data, _ = mroot.lookup(-1, TAG_MDIR)
if not done and rid == -1 and tag == TAG_MDIR:
blocks = frommdir(data)
mdir = Rbyd.fetch(f, block_size, blocks)
# corrupted?
if not mdir:
print('{%s}: %s%s%s' % (
','.join('%04x' % block
for block in it.chain([mdir.block],
mdir.redund_blocks)),
'\x1b[31m' if color else '',
'(corrupted mdir %s)' % mdir.addr(),
'\x1b[m' if color else ''))
corrupted = True
else:
# show the mdir
dbg_mdir(mdir, 0, 0, 0)
# fetch the actual mtree, if there is one
if not args.get('depth') or mdepth < args.get('depth'):
done, rid, tag, w, j, d, data, _ = mroot.lookup(-1, TAG_MTREE)
if not done and rid == -1 and tag == TAG_MTREE:
w, block, trunk, cksum = frombtree(data)
mtree = Rbyd.fetch(f, block_size, block, trunk)
# traverse entries
mbid = -1
while True:
done, mbid, mw, rbyd, rid, tags, path = mtree.btree_lookup(
f, block_size, mbid+1,
depth=args.get('depth', mdepth)-mdepth)
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, (mid_, w_, rbyd_, rid_, tags_) = x
dbg_branch(mid_, w_, rbyd_, rid_, tags_, d)
ppath = path
# corrupted? try to keep printing the tree
if not rbyd:
print('%11s: %*s%s%s%s' % (
'%04x.%04x' % (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 mid_, 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]
# found an mdir in the tags?
mdir__ = None
if (not args.get('depth')
or mdepth+len(path) < args.get('depth')):
mdir__ = next(((tag, j, d, data)
for tag, j, d, data in tags
if tag == TAG_MDIR),
None)
# show other btree entries in certain cases
if args.get('inner') or not mdir__:
dbg_branch(mbid, mw, rbyd, rid, tags, len(path)-1)
if not mdir__:
continue
# fetch the mdir
_, _, _, data = mdir__
blocks = frommdir(data)
mdir_ = Rbyd.fetch(f, block_size, blocks)
# corrupted?
if not mdir_:
print('{%s}: %*s%s%s%s' % (
','.join('%04x' % block
for block in it.chain([mdir_.block],
mdir_.redund_blocks)),
t_width, '',
'\x1b[31m' if color else '',
'(corrupted mdir %s)' % mdir_.addr(),
'\x1b[m' if color else ''))
corrupted = True
else:
# show the mdir
dbg_mdir(mdir_, mbid, mw, len(path))
# force next btree entry to be shown
prbyd = None
if args.get('error_on_corrupt') and corrupted:
sys.exit(2)
if __name__ == "__main__":
import argparse
import sys
parser = argparse.ArgumentParser(
description="Debug littlefs's metadata tree.",
allow_abbrev=False)
parser.add_argument(
'disk',
help="File containing the block device.")
parser.add_argument(
'mroots',
nargs='*',
type=rbydaddr,
help="Block address of the mroots. Defaults to 0x{0,1}.")
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(
'--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 the filesystem is corrupt.")
sys.exit(main(**{k: v
for k, v in vars(parser.parse_intermixed_args()).items()
if v is not None}))