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  1. 09 9月, 2019 5 次提交
    • Q
      btrfs: Detect unbalanced tree with empty leaf before crashing btree operations · 62fdaa52
      由 Qu Wenruo 提交于 
      [BUG]
With crafted image, btrfs will panic at btree operations:

  kernel BUG at fs/btrfs/ctree.c:3894!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:__push_leaf_left+0x6b6/0x6e0
  RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000
  RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000
  RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240
  R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0
  FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0
  Call Trace:
  ? _cond_resched+0x1a/0x50
  push_leaf_left+0x179/0x190
  btrfs_del_items+0x316/0x470
  btrfs_del_csums+0x215/0x3a0
  __btrfs_free_extent.isra.72+0x5a7/0xbe0
  __btrfs_run_delayed_refs+0x539/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace c2425e6e89b5558f ]---

[CAUSE]
The offending csum tree looks like this:

  checksum tree key (CSUM_TREE ROOT_ITEM 0)
  node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
	  ...
	  key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17
	  key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<<
	  key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17
	  ...

  leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8
		  range start 85975040 end 85983232 length 8192
	  ...
  leaf 29642752 items 0 free space 3995 generation 17 owner 0
		      ^ empty leaf            invalid owner ^

  leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368
		  range start 92274688 end 95723520 length 3448832

So we have a corrupted csum tree where one tree leaf is completely
empty, causing unbalanced btree, thus leading to unexpected btree
balance error.

[FIX]
For this particular case, we handle it in two directions to catch it:
- Check if the tree block is empty through btrfs_verify_level_key()
  So that invalid tree blocks won't be read out through
  btrfs_search_slot() and its variants.

- Check 0 tree owner in tree checker
  NO tree is using 0 as its tree owner, detect it and reject at tree
  block read time.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      62fdaa52
    • Q
      btrfs: tree-checker: Add EXTENT_DATA_REF check · 0785a9aa
      由 Qu Wenruo 提交于 
      EXTENT_DATA_REF is a little like DIR_ITEM which contains hash in its
key->offset.

This patch will check the following contents:
- Key->objectid
  Basic alignment check.

- Hash
  Hash of each extent_data_ref item must match key->offset.

- Offset
  Basic alignment check.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      0785a9aa
    • Q
      btrfs: tree-checker: Add simple keyed refs check · e2406a6f
      由 Qu Wenruo 提交于 
      For TREE_BLOCK_REF, SHARED_DATA_REF and SHARED_BLOCK_REF we need to
check:
              | TREE_BLOCK_REF | SHARED_BLOCK_REF | SHARED_BLOCK_REF
--------------+----------------+-----------------+------------------
key->objectid |    Alignment   |     Alignment    |    Alignment
key->offset   |    Any value   |     Alignment    |    Alignment
item_size     |        0       |        0         |   sizeof(le32) (*)

*: sizeof(struct btrfs_shared_data_ref)

So introduce a check to check all these 3 key types together.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      e2406a6f
    • Q
      btrfs: tree-checker: Add EXTENT_ITEM and METADATA_ITEM check · f82d1c7c
      由 Qu Wenruo 提交于 
      This patch introduces the ability to check extent items.

This check involves:
- key->objectid check
  Basic alignment check.

- key->type check
  Against btrfs_extent_item::type and SKINNY_METADATA feature.

- key->offset alignment check for EXTENT_ITEM

- key->offset check for METADATA_ITEM

- item size check
  Both against minimal size and stepping check.

- btrfs_extent_item check
  Checks its flags and generation.

- btrfs_extent_inline_ref checks
  Against 4 types inline ref.
  Checks bytenr alignment and tree level.

- btrfs_extent_item::refs check
  Check against total refs found in inline refs.

This check would be the most complex single item check due to its nature
of inlined items.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      f82d1c7c
    • Q
      btrfs: tree-checker: Add ROOT_ITEM check · 259ee775
      由 Qu Wenruo 提交于 
      This patch will introduce ROOT_ITEM check, which includes:
- Key->objectid and key->offset check
  Currently only some easy check, e.g. 0 as rootid is invalid.

- Item size check
  Root item size is fixed.

- Generation checks
  Generation, generation_v2 and last_snapshot should not be greater than
  super generation + 1

- Level and alignment check
  Level should be in [0, 7], and bytenr must be aligned to sector size.

- Flags check

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203261Reported-by: NJungyeon Yoon <jungyeon.yoon@gmail.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      259ee775
  3. 01 7月, 2019 1 次提交
    • Q
      btrfs: tree-checker: Check if the file extent end overflows · 4c094c33
      由 Qu Wenruo 提交于 
      Under certain conditions, we could have strange file extent item in log
tree like:

  item 18 key (69599 108 397312) itemoff 15208 itemsize 53
	extent data disk bytenr 0 nr 0
	extent data offset 0 nr 18446744073709547520 ram 18446744073709547520

The num_bytes + ram_bytes overflow 64 bit type.

For num_bytes part, we can detect such overflow along with file offset
(key->offset), as file_offset + num_bytes should never go beyond u64.

For ram_bytes part, it's about the decompressed size of the extent, not
directly related to the size.
In theory it is OK to have a large value, and put extra limitation
on RAM bytes may cause unexpected false alerts.

So in tree-checker, we only check if the file offset and num bytes
overflow.
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      4c094c33
  5. 16 5月, 2019 1 次提交
  7. 30 4月, 2019 28 次提交
  9. 17 12月, 2018 1 次提交
  11. 04 12月, 2018 1 次提交
    • Q
      btrfs: tree-checker: Don't check max block group size as current max chunk size limit is unreliable · 10950929
      由 Qu Wenruo 提交于 
      [BUG]
A completely valid btrfs will refuse to mount, with error message like:
  BTRFS critical (device sdb2): corrupt leaf: root=2 block=239681536 slot=172 \
    bg_start=12018974720 bg_len=10888413184, invalid block group size, \
    have 10888413184 expect (0, 10737418240]

This has been reported several times as the 4.19 kernel is now being
used. The filesystem refuses to mount, but is otherwise ok and booting
4.18 is a workaround.

Btrfs check returns no error, and all kernels used on this fs is later
than 2011, which should all have the 10G size limit commit.

[CAUSE]
For a 12 devices btrfs, we could allocate a chunk larger than 10G due to
stripe stripe bump up.

__btrfs_alloc_chunk()
|- max_stripe_size = 1G
|- max_chunk_size = 10G
|- data_stripe = 11
|- if (1G * 11 > 10G) {
       stripe_size = 976128930;
       stripe_size = round_up(976128930, SZ_16M) = 989855744

However the final stripe_size (989855744) * 11 = 10888413184, which is
still larger than 10G.

[FIX]
For the comprehensive check, we need to do the full check at chunk read
time, and rely on bg <-> chunk mapping to do the check.

We could just skip the length check for now.

Fixes: fce466ea ("btrfs: tree-checker: Verify block_group_item")
Cc: stable@vger.kernel.org # v4.19+
Reported-by: NWang Yugui <wangyugui@e16-tech.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
      10950929
  13. 06 11月, 2018 1 次提交
  15. 15 10月, 2018 1 次提交
  17. 06 8月, 2018 1 次提交