Commit Graph

718 Commits

Author SHA1 Message Date
Josef Bacik
e094f48040 btrfs: change root->root_key.objectid to btrfs_root_id()
A comment from Filipe on one of my previous cleanups brought my
attention to a new helper we have for getting the root id of a root,
which makes it easier to read in the code.

The changes where made with the following Coccinelle semantic patch:

// <smpl>
@@
expression E,E1;
@@
(
 E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// </smpl>

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:06 +02:00
Filipe Manana
2066bbfccf btrfs: locking: rename __btrfs_tree_lock() and __btrfs_tree_read_lock()
The __btrfs_tree_lock() and __btrfs_tree_read_lock() are using a naming
with a double underscore prefix, which is specially not proper for
exported functions. Remove the double underscore prefix from their name
and add the "_nested" suffix.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:00 +02:00
Chengming Zhou
ef5a05c557 btrfs: remove SLAB_MEM_SPREAD flag use
The SLAB_MEM_SPREAD flag used to be implemented in SLAB, which was
removed as of v6.8-rc1, so it became a dead flag since the commit
16a1d96835 ("mm/slab: remove mm/slab.c and slab_def.h"). And the
series[1] went on to mark it obsolete to avoid confusion for users.
Here we can just remove all its users, which has no functional change.

[1] https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-05 17:13:23 +01:00
Kunwu Chan
66ce5447d8 btrfs: use KMEM_CACHE() to create btrfs_path cache
Use the KMEM_CACHE() macro instead of kmem_cache_create() to simplify
the creation of SLAB caches when the default values are used.

Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:53 +01:00
David Sterba
5378ea6ea0 btrfs: unify handling of return values of btrfs_insert_empty_items()
The error values returned by btrfs_insert_empty_items() are following
the common patter of 0/-errno, but some callers check for a value > 0,
which can't happen. Document that and update calls to not expect
positive values.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:48 +01:00
Qu Wenruo
84cda1a608 btrfs: cache folio size and shift in extent_buffer
After the conversion to folio interfaces (but without the patch to
enable larger folio allocation), there is an LTP report about observable
performance drop on metadata heavy operations.

https://lore.kernel.org/linux-btrfs/202312221750.571925bd-oliver.sang@intel.com/

This drop is caused by the extra code of calculating the
folio_size()/folio_shift(), instead of the old hard coded
PAGE_SIZE/PAGE_SHIFT.

To slightly reduce the overhead, just cache both folio_size and
folio_shift in extent_buffer.

The two new members (u32 folio_size and u8 folio_shift) are stored
inside the holes of extent_buffer. folio_size is shared with len, which
is reduced to u32. The size of eb does not change.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:45 +01:00
Qu Wenruo
8d99361835 btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios
These two functions are still using the old page based code, which is
not going to handle larger folios at all.

The migration itself is going to involve the following changes:

- PAGE_SIZE -> folio_size()
- PAGE_SHIFT -> folio_shift()
- get_eb_page_index() -> get_eb_folio_index()
- get_eb_offset_in_page() -> get_eb_offset_in_folio()

And since we're going to support larger folios, although above straight
conversion is good enough, this patch would add extra comments in the
involved functions to explain why the same single line code can now
cover 3 cases:

- folio_size == PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The common, non-subpage case with per-page folio.

- folio_size > PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The incoming larger folio, non-subpage case.

- folio_size == PAGE_SIZE, sectorsize < PAGE_SIZE, nodesize < PAGE_SIZE
  The existing subpage case, we won't larger folio anyway.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00
Qu Wenruo
082d5bb9b3 btrfs: migrate extent_buffer::pages[] to folio
For now extent_buffer::pages[] are still only accepting single page
pointer, thus we can migrate to folios pretty easily.

As for single page, page and folio are 1:1 mapped, including their page
flags.

This patch would just do the conversion from struct page to struct
folio, providing the first step to higher order folio in the future.

This conversion is pretty simple:

- extent_buffer::pages[] -> extent_buffer::folios[]

- page_address(eb->pages[i]) -> folio_address(eb->pages[i])

- eb->pages[i] -> folio_page(eb->folios[i], 0)

There would be more specific cleanups preparing for the incoming higher
order folio support.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:01:04 +01:00
Filipe Manana
80d197fe04 btrfs: make the logic from btrfs_block_can_be_shared() easier to read
The logic in btrfs_block_can_be_shared() is hard to follow as we have a
lot of conditions in a single if statement including a subexpression with
a logical or and two nested if statements inside the main if statement.

Make this easier to read by using separate if statements that return
immediately when we find a condition that determines if a block can be
or can not be shared.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:00 +01:00
Filipe Manana
6e5de50fc5 btrfs: use bool for return type of btrfs_block_can_be_shared()
Currently btrfs_block_can_be_shared() returns an int that is used as a
boolean. Since it all it needs is to return true or false, and it can't
return errors for example, change the return type from int to bool to
make it a bit more readable and obvious.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:00 +01:00
Linus Torvalds
9bacdd8996 for-6.7-rc1-tag
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEE8rQSAMVO+zA4DBdWxWXV+ddtWDsFAmVSO50ACgkQxWXV+ddt
 WDuiyg/7BZviFAyiQMAzpA319qRJZ+EemfTdF/k69q4axGYuvqVdXKnpOV44AR4I
 dKcHLOPpDZIxsh8lFytkm1UEAHptw1v7A64c+gcdjGK0tAA7aKbw/1nmNysowT23
 L0v2+34hkBUfG8A3uVgOwL1rjItEX5Fl54slpVsazSqlEbKrqC4MGNjmqdp3IOeC
 qfXTgkvkXmm8s8NyoJybKewM9Aw0tmK0jkAFHA+2sgcZPYKXjqWGv9KUOsXnCx5o
 3kPWIRT1sj4q2qzrgP14Q12O6qPLZ2/0oTBhi6nhj8+N1yiH+USS5zBITegF+w2n
 leQeVHtyBYHlPYQSQlCIZy7+10gkePvs+JmoAuL8YFISnGYnvOZqCeArlV7cnNI3
 CQt7ZBER5Dqw78Y756usUhpYrLWa9kOpcPVRmjJ/R62+TY1FkkyY7irETbn5EGjI
 NlhEa4PMYeYpAOccoxWEm9tIiiVD1abURhVBdn3Znfcb1Sv/lrGBlo9DYGFCxbBh
 xU1JP7sly8w0aPLqCbn1X3VY8dXp+CeYz4FQabHjQA/zr9lF08/pRYj3haAbYAyH
 0KphXurwz/YqY+LmRg7SbQ/KMgBAiBV8Qk9JyNvdvaQbnYnq7CWdpoHcpZu3mvpb
 HLGoXew58kZaSfxLHlcT5wwYlbq0rooXRstuFg2+BBcOFOMCQfw=
 =GM+1
 -----END PGP SIGNATURE-----

Merge tag 'for-6.7-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix potential overflow in returned value from SEARCH_TREE_V2
   ioctl on 32bit architecture

 - zoned mode fixes:

     - drop unnecessary write pointer check for RAID0/RAID1/RAID10
       profiles, now it works because of raid-stripe-tree

     - wait for finishing the zone when direct IO needs a new
       allocation

 - simple quota fixes:

     - pass correct owning root pointer when cleaning up an
       aborted transaction

     - fix leaking some structures when processing delayed refs

     - change key type number of BTRFS_EXTENT_OWNER_REF_KEY,
       reorder it before inline refs that are supposed to be
       sorted, keeping the original number would complicate a lot
       of things; this change needs an updated version of
       btrfs-progs to work and filesystems need to be recreated

 - fix error pointer dereference after failure to allocate fs
   devices

 - fix race between accounting qgroup extents and removing a
   qgroup

* tag 'for-6.7-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: make OWNER_REF_KEY type value smallest among inline refs
  btrfs: fix qgroup record leaks when using simple quotas
  btrfs: fix race between accounting qgroup extents and removing a qgroup
  btrfs: fix error pointer dereference after failure to allocate fs devices
  btrfs: make found_logical_ret parameter mandatory for function queue_scrub_stripe()
  btrfs: get correct owning_root when dropping snapshot
  btrfs: zoned: wait for data BG to be finished on direct IO allocation
  btrfs: zoned: drop no longer valid write pointer check
  btrfs: directly return 0 on no error code in btrfs_insert_raid_extent()
  btrfs: use u64 for buffer sizes in the tree search ioctls
2023-11-13 09:09:12 -08:00
Josef Bacik
d8ba2a91fc btrfs: get correct owning_root when dropping snapshot
Dave reported a bug where we were aborting the transaction while trying
to cleanup the squota reservation for an extent.

This turned out to be because we're doing btrfs_header_owner(next) in
do_walk_down when we decide to free the block.  However in this code
block we haven't explicitly read next, so it could be stale.  We would
then get whatever garbage happened to be in the pages at this point.
The commit that introduced that is "btrfs: track owning root in
btrfs_ref".

Fix this by saving the owner_root when we do the
btrfs_lookup_extent_info().  We always do this in do_walk_down, it is
how we make the decision of whether or not to delete the block.  This is
cheap because we've already done the extent item lookup at this point,
so it's straightforward to just grab the owner root as well.

Then we can use this when deleting the metadata block without needing to
force a read of the extent buffer to find the owner.

This fixes the problem that Dave reported.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-11-03 16:39:06 +01:00
Linus Torvalds
d5acbc60fa for-6.7-tag
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEE8rQSAMVO+zA4DBdWxWXV+ddtWDsFAmU/xAEACgkQxWXV+ddt
 WDvYKg//SjTimA5Nins9mb4jdz8n+dDeZnQhKzy3FqInU41EzDRc4WwnEODmDlTa
 AyU9rGB3k0JNSUc075jZFCyLqq/ARiOqRi4x33Gk0ckIlc4X5OgBoqP2XkPh0VlP
 txskLCrmhc3pwyR4ErlFDX2jebIUXfkv39bJuE40grGvUatRe+WNq0ERIrgO8RAr
 Rc3hBotMH8AIqfD1L6j1ZiZIAyrOkT1BJMuqeoq27/gJZn/MRhM9TCrMTzfWGaoW
 SxPrQiCDEN3KECsOY/caroMn3AekDijg/ley1Nf7Z0N6oEV+n4VWWPBFE9HhRz83
 9fIdvSbGjSJF6ekzTjcVXPAbcuKZFzeqOdBRMIW3TIUo7mZQyJTVkMsc1y/NL2Z3
 9DhlRLIzvWJJjt1CEK0u18n5IU+dGngdktbhWWIuIlo8r+G/iKR/7zqU92VfWLHL
 Z7/eh6HgH5zr2bm+yKORbrUjkv4IVhGVarW8D4aM+MCG0lFN2GaPcJCCUrp4n7rZ
 PzpQbxXa38ANBk6hsp4ndS8TJSBL9moY8tumzLcKg97nzNMV6KpBdV/G6/QfRLCN
 3kM6UbwTAkMwGcQS86Mqx6s04ORLnQeD6f7N6X4Ppx0Mi/zkjI2HkRuvQGp12B0v
 iZjCCZAYY2Iu+/TU0GrCXSss/grzIAUPzM9msyV3XGO/VBpwdec=
 =9TVx
 -----END PGP SIGNATURE-----

Merge tag 'for-6.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "New features:

   - raid-stripe-tree

     New tree for logical file extent mapping where the physical mapping
     may not match on multiple devices. This is now used in zoned mode
     to implement RAID0/RAID1* profiles, but can be used in non-zoned
     mode as well. The support for RAID56 is in development and will
     eventually fix the problems with the current implementation. This
     is a backward incompatible feature and has to be enabled at mkfs
     time.

   - simple quota accounting (squota)

     A simplified mode of qgroup that accounts all space on the initial
     extent owners (a subvolume), the snapshots are then cheap to create
     and delete. The deletion of snapshots in fully accounting qgroups
     is a known CPU/IO performance bottleneck.

     The squota is not suitable for the general use case but works well
     for containers where the original subvolume exists for the whole
     time. This is a backward incompatible feature as it needs extending
     some structures, but can be enabled on an existing filesystem.

   - temporary filesystem fsid (temp_fsid)

     The fsid identifies a filesystem and is hard coded in the
     structures, which disallows mounting the same fsid found on
     different devices.

     For a single device filesystem this is not strictly necessary, a
     new temporary fsid can be generated on mount e.g. after a device is
     cloned. This will be used by Steam Deck for root partition A/B
     testing, or can be used for VM root images.

  Other user visible changes:

   - filesystems with partially finished metadata_uuid conversion cannot
     be mounted anymore and the uuid fixup has to be done by btrfs-progs
     (btrfstune).

  Performance improvements:

   - reduce reservations for checksum deletions (with enabled free space
     tree by factor of 4), on a sample workload on file with many
     extents the deletion time decreased by 12%

   - make extent state merges more efficient during insertions, reduce
     rb-tree iterations (run time of critical functions reduced by 5%)

  Core changes:

   - the integrity check functionality has been removed, this was a
     debugging feature and removal does not affect other integrity
     checks like checksums or tree-checker

   - space reservation changes:

      - more efficient delayed ref reservations, this avoids building up
        too much work or overusing or exhausting the global block
        reserve in some situations

      - move delayed refs reservation to the transaction start time,
        this prevents some ENOSPC corner cases related to exhaustion of
        global reserve

      - improvements in reducing excessive reservations for block group
        items

      - adjust overcommit logic in near full situations, account for one
        more chunk to eventually allocate metadata chunk, this is mostly
        relevant for small filesystems (<10GiB)

   - single device filesystems are scanned but not registered (except
     seed devices), this allows temp_fsid to work

   - qgroup iterations do not need GFP_ATOMIC allocations anymore

   - cleanups, refactoring, reduced data structure size, function
     parameter simplifications, error handling fixes"

* tag 'for-6.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (156 commits)
  btrfs: open code timespec64 in struct btrfs_inode
  btrfs: remove redundant log root tree index assignment during log sync
  btrfs: remove redundant initialization of variable dirty in btrfs_update_time()
  btrfs: sysfs: show temp_fsid feature
  btrfs: disable the device add feature for temp-fsid
  btrfs: disable the seed feature for temp-fsid
  btrfs: update comment for temp-fsid, fsid, and metadata_uuid
  btrfs: remove pointless empty log context list check when syncing log
  btrfs: update comment for struct btrfs_inode::lock
  btrfs: remove pointless barrier from btrfs_sync_file()
  btrfs: add and use helpers for reading and writing last_trans_committed
  btrfs: add and use helpers for reading and writing fs_info->generation
  btrfs: add and use helpers for reading and writing log_transid
  btrfs: add and use helpers for reading and writing last_log_commit
  btrfs: support cloned-device mount capability
  btrfs: add helper function find_fsid_by_disk
  btrfs: stop reserving excessive space for block group item insertions
  btrfs: stop reserving excessive space for block group item updates
  btrfs: reorder btrfs_inode to fill gaps
  btrfs: open code btrfs_ordered_inode_tree in btrfs_inode
  ...
2023-10-30 10:42:06 -10:00
Filipe Manana
eb96e22193 btrfs: fix unwritten extent buffer after snapshotting a new subvolume
When creating a snapshot of a subvolume that was created in the current
transaction, we can end up not persisting a dirty extent buffer that is
referenced by the snapshot, resulting in IO errors due to checksum failures
when trying to read the extent buffer later from disk. A sequence of steps
that leads to this is the following:

1) At ioctl.c:create_subvol() we allocate an extent buffer, with logical
   address 36007936, for the leaf/root of a new subvolume that has an ID
   of 291. We mark the extent buffer as dirty, and at this point the
   subvolume tree has a single node/leaf which is also its root (level 0);

2) We no longer commit the transaction used to create the subvolume at
   create_subvol(). We used to, but that was recently removed in
   commit 1b53e51a4a ("btrfs: don't commit transaction for every subvol
   create");

3) The transaction used to create the subvolume has an ID of 33, so the
   extent buffer 36007936 has a generation of 33;

4) Several updates happen to subvolume 291 during transaction 33, several
   files created and its tree height changes from 0 to 1, so we end up with
   a new root at level 1 and the extent buffer 36007936 is now a leaf of
   that new root node, which is extent buffer 36048896.

   The commit root remains as 36007936, since we are still at transaction
   33;

5) Creation of a snapshot of subvolume 291, with an ID of 292, starts at
   ioctl.c:create_snapshot(). This triggers a commit of transaction 33 and
   we end up at transaction.c:create_pending_snapshot(), in the critical
   section of a transaction commit.

   There we COW the root of subvolume 291, which is extent buffer 36048896.
   The COW operation returns extent buffer 36048896, since there's no need
   to COW because the extent buffer was created in this transaction and it
   was not written yet.

   The we call btrfs_copy_root() against the root node 36048896. During
   this operation we allocate a new extent buffer to turn into the root
   node of the snapshot, copy the contents of the root node 36048896 into
   this snapshot root extent buffer, set the owner to 292 (the ID of the
   snapshot), etc, and then we call btrfs_inc_ref(). This will create a
   delayed reference for each leaf pointed by the root node with a
   reference root of 292 - this includes a reference for the leaf
   36007936.

   After that we set the bit BTRFS_ROOT_FORCE_COW in the root's state.

   Then we call btrfs_insert_dir_item(), to create the directory entry in
   in the tree of subvolume 291 that points to the snapshot. This ends up
   needing to modify leaf 36007936 to insert the respective directory
   items. Because the bit BTRFS_ROOT_FORCE_COW is set for the root's state,
   we need to COW the leaf. We end up at btrfs_force_cow_block() and then
   at update_ref_for_cow().

   At update_ref_for_cow() we call btrfs_block_can_be_shared() which
   returns false, despite the fact the leaf 36007936 is shared - the
   subvolume's root and the snapshot's root point to that leaf. The
   reason that it incorrectly returns false is because the commit root
   of the subvolume is extent buffer 36007936 - it was the initial root
   of the subvolume when we created it. So btrfs_block_can_be_shared()
   which has the following logic:

   int btrfs_block_can_be_shared(struct btrfs_root *root,
                                 struct extent_buffer *buf)
   {
       if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
           buf != root->node && buf != root->commit_root &&
           (btrfs_header_generation(buf) <=
            btrfs_root_last_snapshot(&root->root_item) ||
            btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
               return 1;

       return 0;
   }

   Returns false (0) since 'buf' (extent buffer 36007936) matches the
   root's commit root.

   As a result, at update_ref_for_cow(), we don't check for the number
   of references for extent buffer 36007936, we just assume it's not
   shared and therefore that it has only 1 reference, so we set the local
   variable 'refs' to 1.

   Later on, in the final if-else statement at update_ref_for_cow():

   static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
                                          struct btrfs_root *root,
                                          struct extent_buffer *buf,
                                          struct extent_buffer *cow,
                                          int *last_ref)
   {
      (...)
      if (refs > 1) {
          (...)
      } else {
          (...)
          btrfs_clear_buffer_dirty(trans, buf);
          *last_ref = 1;
      }
   }

   So we mark the extent buffer 36007936 as not dirty, and as a result
   we don't write it to disk later in the transaction commit, despite the
   fact that the snapshot's root points to it.

   Attempting to access the leaf or dumping the tree for example shows
   that the extent buffer was not written:

   $ btrfs inspect-internal dump-tree -t 292 /dev/sdb
   btrfs-progs v6.2.2
   file tree key (292 ROOT_ITEM 33)
   node 36110336 level 1 items 2 free space 119 generation 33 owner 292
   node 36110336 flags 0x1(WRITTEN) backref revision 1
   checksum stored a8103e3e
   checksum calced a8103e3e
   fs uuid 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79
   chunk uuid e8c9c885-78f4-4d31-85fe-89e5f5fd4a07
           key (256 INODE_ITEM 0) block 36007936 gen 33
           key (257 EXTENT_DATA 0) block 36052992 gen 33
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   total bytes 107374182400
   bytes used 38572032
   uuid 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79

   The respective on disk region is full of zeroes as the device was
   trimmed at mkfs time.

   Obviously 'btrfs check' also detects and complains about this:

   $ btrfs check /dev/sdb
   Opening filesystem to check...
   Checking filesystem on /dev/sdb
   UUID: 90c9a46f-ae9f-4626-9aff-0cbf3e2e3a79
   generation: 33 (33)
   [1/7] checking root items
   [2/7] checking extents
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   bad tree block 36007936, bytenr mismatch, want=36007936, have=0
   owner ref check failed [36007936 4096]
   ERROR: errors found in extent allocation tree or chunk allocation
   [3/7] checking free space tree
   [4/7] checking fs roots
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   checksum verify failed on 36007936 wanted 0x00000000 found 0x86005f29
   bad tree block 36007936, bytenr mismatch, want=36007936, have=0
   The following tree block(s) is corrupted in tree 292:
        tree block bytenr: 36110336, level: 1, node key: (256, 1, 0)
   root 292 root dir 256 not found
   ERROR: errors found in fs roots
   found 38572032 bytes used, error(s) found
   total csum bytes: 16048
   total tree bytes: 1265664
   total fs tree bytes: 1118208
   total extent tree bytes: 65536
   btree space waste bytes: 562598
   file data blocks allocated: 65978368
    referenced 36569088

Fix this by updating btrfs_block_can_be_shared() to consider that an
extent buffer may be shared if it matches the commit root and if its
generation matches the current transaction's generation.

This can be reproduced with the following script:

   $ cat test.sh
   #!/bin/bash

   MNT=/mnt/sdi
   DEV=/dev/sdi

   # Use a filesystem with a 64K node size so that we have the same node
   # size on every machine regardless of its page size (on x86_64 default
   # node size is 16K due to the 4K page size, while on PPC it's 64K by
   # default). This way we can make sure we are able to create a btree for
   # the subvolume with a height of 2.
   mkfs.btrfs -f -n 64K $DEV
   mount $DEV $MNT

   btrfs subvolume create $MNT/subvol

   # Create a few empty files on the subvolume, this bumps its btree
   # height to 2 (root node at level 1 and 2 leaves).
   for ((i = 1; i <= 300; i++)); do
       echo -n > $MNT/subvol/file_$i
   done

   btrfs subvolume snapshot -r $MNT/subvol $MNT/subvol/snap

   umount $DEV

   btrfs check $DEV

Running it on a 6.5 kernel (or any 6.6-rc kernel at the moment):

   $ ./test.sh
   Create subvolume '/mnt/sdi/subvol'
   Create a readonly snapshot of '/mnt/sdi/subvol' in '/mnt/sdi/subvol/snap'
   Opening filesystem to check...
   Checking filesystem on /dev/sdi
   UUID: bbdde2ff-7d02-45ca-8a73-3c36f23755a1
   [1/7] checking root items
   [2/7] checking extents
   parent transid verify failed on 30539776 wanted 7 found 5
   parent transid verify failed on 30539776 wanted 7 found 5
   parent transid verify failed on 30539776 wanted 7 found 5
   Ignoring transid failure
   owner ref check failed [30539776 65536]
   ERROR: errors found in extent allocation tree or chunk allocation
   [3/7] checking free space tree
   [4/7] checking fs roots
   parent transid verify failed on 30539776 wanted 7 found 5
   Ignoring transid failure
   Wrong key of child node/leaf, wanted: (256, 1, 0), have: (2, 132, 0)
   Wrong generation of child node/leaf, wanted: 5, have: 7
   root 257 root dir 256 not found
   ERROR: errors found in fs roots
   found 917504 bytes used, error(s) found
   total csum bytes: 0
   total tree bytes: 851968
   total fs tree bytes: 393216
   total extent tree bytes: 65536
   btree space waste bytes: 736550
   file data blocks allocated: 0
    referenced 0

A test case for fstests will follow soon.

Fixes: 1b53e51a4a ("btrfs: don't commit transaction for every subvol create")
CC: stable@vger.kernel.org # 6.5+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-23 17:17:30 +02:00
Filipe Manana
6422b4cd95 btrfs: move btrfs_realloc_node() from ctree.c into defrag.c
btrfs_realloc_node() is only used by the defrag code. Nowadays we have a
defrag.c file, so move it, and its helper close_blocks(), into defrag.c.

During the move also do a few minor cosmetic changes:

1) Change the return value of close_blocks() from int to bool;

2) Use SZ_32K instead of 32768 at close_blocks();

3) Make some variables const in btrfs_realloc_node(), 'blocksize' and
   'end_slot';

4) Get rid of 'parent_nritems' variable, in both places where it was
   used it could be replaced by calling btrfs_header_nritems(parent);

5) Change the type of a couple variables from int to bool;

6) Rename variable 'err' to 'ret', as that's the most common name we
   use to track the return value of a function;

7) Move some variables from the top scope to the scope of the for loop
   where they are used.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:14 +02:00
Filipe Manana
79d25df0d7 btrfs: export comp_keys() from ctree.c as btrfs_comp_keys()
Export comp_keys() out of ctree.c, as btrfs_comp_keys(), so that in a
later patch we can move out defrag specific code from ctree.c into
defrag.c.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:14 +02:00
Filipe Manana
95f93bc4cb btrfs: rename and export __btrfs_cow_block()
Rename and export __btrfs_cow_block() as btrfs_force_cow_block(). This is
to allow to move defrag specific code out of ctree.c and into defrag.c in
one of the next patches.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:14 +02:00
Filipe Manana
b8bf4e4d6a btrfs: use round_down() to align block offset at btrfs_cow_block()
At btrfs_cow_block() we can use round_down() to align the extent buffer's
logical offset to the start offset of a metadata block group, instead of
the less easy to read set of bitwise operations (two plus one subtraction).
So replace the bitwise operations with a round_down() call.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:14 +02:00
Filipe Manana
7bff16e3ff btrfs: remove noinline attribute from btrfs_cow_block()
It's pointless to have the noiline attribute for btrfs_cow_block(), as the
function is exported and widely used. So remove it.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:14 +02:00
Boris Burkov
60ea105a0f btrfs: qgroup: track metadata relocation COW with simple quota
Relocation COWs metadata blocks in two cases for the reloc root:

- copying the subvolume root item when creating the reloc root
- copying a btree node when there is a COW during relocation

In both cases, the resulting btree node hits an abnormal code path with
respect to the owner field in its btrfs_header. It first creates the
root item for the new objectid, which populates the reloc root id, and
it at this point that delayed refs are created.

Later, it fully copies the old node into the new node (including the
original owner field) which overwrites it. This results in a simple
quotas mismatch where we run the delayed ref for the reloc root which
has no simple quota effect (reloc root is not an fstree) but when we
ultimately delete the node, the owner is the real original fstree and we
do free the space.

To work around this without tampering with the behavior of relocation,
add a parameter to btrfs_add_tree_block that lets the relocation code
path specify a different owning root than the "operating" root (in this
case, owning root is the real root and the operating root is the reloc
root). These can naturally be plumbed into delayed refs that have the
same concept.

Note that this is a double count in some sense, but a relatively natural
one, as there are really two extents, and the old one will be deleted
soon. This is consistent with how data relocation extents are accounted
by simple quotas.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:12 +02:00
Filipe Manana
50564b651d btrfs: abort transaction on generation mismatch when marking eb as dirty
When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00
David Sterba
ed164802e8 btrfs: rename errno identifiers to error
We sync the kernel files to userspace and the 'errno' symbol is defined
by standard library, which does not matter in kernel but the parameters
or local variables could clash. Rename them all.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00
David Sterba
02cd00fa78 btrfs: reduce arguments of helpers space accounting root item
There are two helpers to increase used bytes of root items that add or
subtract one node size, we don't need to pass the argument for that.
Rename the function so it matches the root item member that gets
changed.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:04 +02:00
David Sterba
9580503bcb btrfs: reformat remaining kdoc style comments
Function name in the comment does not bring much value to code not
exposed as API and we don't stick to the kdoc format anymore. Update
formatting of parameter descriptions.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:04 +02:00
Filipe Manana
e36f949140 btrfs: error out when reallocating block for defrag using a stale transaction
At btrfs_realloc_node() we have these checks to verify we are not using a
stale transaction (a past transaction with an unblocked state or higher),
and the only thing we do is to trigger two WARN_ON(). This however is a
critical problem, highly unexpected and if it happens it's most likely due
to a bug, so we should error out and turn the fs into error state so that
such issue is much more easily noticed if it's triggered.

The problem is critical because in btrfs_realloc_node() we COW tree blocks,
and using such stale transaction will lead to not persisting the extent
buffers used for the COW operations, as allocating tree block adds the
range of the respective extent buffers to the ->dirty_pages iotree of the
transaction, and a stale transaction, in the unlocked state or higher,
will not flush dirty extent buffers anymore, therefore resulting in not
persisting the tree block and resource leaks (not cleaning the dirty_pages
iotree for example).

So do the following changes:

1) Return -EUCLEAN if we find a stale transaction;

2) Turn the fs into error state, with error -EUCLEAN, so that no
   transaction can be committed, and generate a stack trace;

3) Combine both conditions into a single if statement, as both are related
   and have the same error message;

4) Mark the check as unlikely, since this is not expected to ever happen.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-04 01:04:33 +02:00
Filipe Manana
a2caab2988 btrfs: error when COWing block from a root that is being deleted
At btrfs_cow_block() we check if the block being COWed belongs to a root
that is being deleted and if so we log an error message. However this is
an unexpected case and it indicates a bug somewhere, so we should return
an error and abort the transaction. So change this in the following ways:

1) Abort the transaction with -EUCLEAN, so that if the issue ever happens
   it can easily be noticed;

2) Change the logged message level from error to critical, and change the
   message itself to print the block's logical address and the ID of the
   root;

3) Return -EUCLEAN to the caller;

4) As this is an unexpected scenario, that should never happen, mark the
   check as unlikely, allowing the compiler to potentially generate better
   code.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-04 01:04:28 +02:00
Filipe Manana
48774f3bf8 btrfs: error out when COWing block using a stale transaction
At btrfs_cow_block() we have these checks to verify we are not using a
stale transaction (a past transaction with an unblocked state or higher),
and the only thing we do is to trigger a WARN with a message and a stack
trace. This however is a critical problem, highly unexpected and if it
happens it's most likely due to a bug, so we should error out and turn the
fs into error state so that such issue is much more easily noticed if it's
triggered.

The problem is critical because using such stale transaction will lead to
not persisting the extent buffer used for the COW operation, as allocating
a tree block adds the range of the respective extent buffer to the
->dirty_pages iotree of the transaction, and a stale transaction, in the
unlocked state or higher, will not flush dirty extent buffers anymore,
therefore resulting in not persisting the tree block and resource leaks
(not cleaning the dirty_pages iotree for example).

So do the following changes:

1) Return -EUCLEAN if we find a stale transaction;

2) Turn the fs into error state, with error -EUCLEAN, so that no
   transaction can be committed, and generate a stack trace;

3) Combine both conditions into a single if statement, as both are related
   and have the same error message;

4) Mark the check as unlikely, since this is not expected to ever happen.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-04 01:04:24 +02:00
Filipe Manana
7569141e8f btrfs: replace BUG_ON() at split_item() with proper error handling
There's no need to BUG_ON() at split_item() if the leaf does not have
enough free space for the new item, we can just return -ENOSPC since
the caller can deal with errors from split_item(). Also, as this is a
very unlikely condition to happen, because the caller has invoked
setup_leaf_for_split() before calling split_item(), surround the
condition with a WARN_ON() which makes it easier to notice this
unexpected condition and tags the if branch with 'unlikely' as well.

I've actually once hit this BUG_ON() with some incorrect code changes
I had, which was very inconvenient as it required rebooting the VM.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
751a27615d btrfs: do not BUG_ON() on tree mod log failures at btrfs_del_ptr()
At btrfs_del_ptr(), instead of doing a BUG_ON() in case we fail to record
tree mod log operations, do a transaction abort and return the error to
the callers. There's really no need for the BUG_ON() as we can release all
resources in the context of all callers, and we have to abort because other
future tree searches that use the tree mod log (btrfs_search_old_slot())
may get inconsistent results if other operations modify the tree after
that failure and before the tree mod log based search.

This implies btrfs_del_ptr() return an int instead of void, and making all
callers check for returned errors.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
50b5d1fc41 btrfs: do not BUG_ON() on tree mod log failures at insert_ptr()
At insert_ptr(), instead of doing a BUG_ON() in case we fail to record
tree mod log operations, do a transaction abort and return the error to
the callers. There's really no need for the BUG_ON() as we can release all
resources in the context of all callers, and we have to abort because other
future tree searches that use the tree mod log (btrfs_search_old_slot())
may get inconsistent results if other operations modify the tree after
that failure and before the tree mod log based search.

This implies making insert_ptr() return an int instead of void, and making
all callers check for returned errors.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
f61aa7ba08 btrfs: do not BUG_ON() on tree mod log failure at insert_new_root()
At insert_new_root(), instead of doing a BUG_ON() in case we fail to
record the tree mod log operation, just return the error to the callers
after releasing the allocated tree block. At this point we haven't made
any changes to the b+tree, so we haven't left it in an inconsistent state
and therefore have no need to abort the transaction. All we need to do is
to unlock and free the extent buffer we just allocated with the purpose
of making it the new root.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
11d6ae0355 btrfs: do not BUG_ON() on tree mod log failures at push_nodes_for_insert()
At push_nodes_for_insert(), instead of doing a BUG_ON() in case we fail to
record tree mod log operations, do a transaction abort and return the
error to the caller. There's really no need for the BUG_ON() as we can
release all resources in this context, and we have to abort because other
future tree searches that use the tree mod log (btrfs_search_old_slot())
may get inconsistent results if other operations modify the tree after
that failure and before the tree mod log based search.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
eced687e22 btrfs: abort transaction at update_ref_for_cow() when ref count is zero
At update_ref_for_cow() we are calling btrfs_handle_fs_error() if we find
that the extent buffer has an unexpected ref count of zero, however we can
simply use btrfs_abort_transaction(), which achieves the same purposes: to
turn the fs to error state, abort the current transaction and turn the fs
to RO mode as well. Besides that, btrfs_abort_transaction() also prints a
stack trace which makes it more useful.

Also, as this is a very unexpected situation, indicating a serious
corruption/inconsistency, tag the if branch as 'unlikely', set the error
code to -EUCLEAN instead of -EROFS, and log an explicit message.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:39 +02:00
Filipe Manana
725026ed59 btrfs: abort transaction at balance_level() when left child is missing
At balance_level() we are calling btrfs_handle_fs_error() when the middle
child only has 1 item and the left child is missing, however we can simply
use btrfs_abort_transaction(), which achieves the same purposes: to turn
the fs to error state, abort the current transaction and turn the fs to
RO mode. Besides that, btrfs_abort_transaction() also prints a stack trace
which makes it more useful.

Also, as this is a highly unexpected case and it's about a b+tree
inconsistency, change the error code from -EROFS to -EUCLEAN, tag the if
branch as 'unlikely' and log an explicit error message.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
87b8e9d06e btrfs: avoid unnecessarily setting the fs to RO and error state at balance_level()
At balance_level(), when trying to promote a child node to a root node, if
we fail to read the child we call btrfs_handle_fs_error(), which turns the
fs to RO mode and sets it to error state as well, causing any ongoing
transaction to abort. This however is not necessary because at that point
we have not made any change yet at balance_level(), so any error reading
the child node does not leaves us in any inconsistent state. Therefore we
can just return the error to the caller.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
daefe4d435 btrfs: rename enospc label to out at balance_level()
At balance_level() we have this 'enospc' label where we jump to in case
we get an error at several places. However that error is certainly not
-ENOSPC in call cases, it can be -EIO or -ENOMEM when reading a child
extent buffer for example, or -ENOMEM when trying to record tree mod log
operations. So to make this less confusing, rename the label to 'out'.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
39020d8abc btrfs: do not BUG_ON() on tree mod log failure at balance_level()
At balance_level(), instead of doing a BUG_ON() in case we fail to record
tree mod log operations, do a transaction abort and return the error to
the callers. There's really no need for the BUG_ON() as we can release
all resources in this context, and we have to abort because other future
tree searches that use the tree mod log (btrfs_search_old_slot()) may get
inconsistent results if other operations modify the tree after that
failure and before the tree mod log based search.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
40b0a74938 btrfs: do not BUG_ON() on tree mod log failure at __btrfs_cow_block()
At __btrfs_cow_block(), instead of doing a BUG_ON() in case we fail to
record a tree mod log root insertion operation, do a transaction abort
instead. There's really no need for the BUG_ON(), we can properly
release all resources in this context and turn the filesystem to RO mode
and in an error state instead.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
ede600e497 btrfs: fix extent buffer leak after tree mod log failure at split_node()
At split_node(), if we fail to log the tree mod log copy operation, we
return without unlocking the split extent buffer we just allocated and
without decrementing the reference we own on it. Fix this by unlocking
it and decrementing the ref count before returning.

Fixes: 5de865eebb ("Btrfs: fix tree mod logging")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Filipe Manana
d09c51521f btrfs: add missing error handling when logging operation while COWing extent buffer
When COWing an extent buffer that is not the root node, we need to log in
the tree mod log that we replaced a pointer in the parent node, otherwise
a tree mod log user doing a search on the b+tree can return incorrect
results (that miss something). We are doing the call to
btrfs_tree_mod_log_insert_key() but we totally ignore its return value.

So fix this by adding the missing error handling, resulting in a
transaction abort and freeing the COWed extent buffer.

Fixes: f230475e62 ("Btrfs: put all block modifications into the tree mod log")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:38 +02:00
Boris Burkov
5cead5422a btrfs: insert tree mod log move in push_node_left
There is a fairly unlikely race condition in tree mod log rewind that
can result in a kernel panic which has the following trace:

  [530.569] BTRFS critical (device sda3): unable to find logical 0 length 4096
  [530.585] BTRFS critical (device sda3): unable to find logical 0 length 4096
  [530.602] BUG: kernel NULL pointer dereference, address: 0000000000000002
  [530.618] #PF: supervisor read access in kernel mode
  [530.629] #PF: error_code(0x0000) - not-present page
  [530.641] PGD 0 P4D 0
  [530.647] Oops: 0000 [#1] SMP
  [530.654] CPU: 30 PID: 398973 Comm: below Kdump: loaded Tainted: G S         O  K   5.12.0-0_fbk13_clang_7455_gb24de3bdb045 #1
  [530.680] Hardware name: Quanta Mono Lake-M.2 SATA 1HY9U9Z001G/Mono Lake-M.2 SATA, BIOS F20_3A15 08/16/2017
  [530.703] RIP: 0010:__btrfs_map_block+0xaa/0xd00
  [530.755] RSP: 0018:ffffc9002c2f7600 EFLAGS: 00010246
  [530.767] RAX: ffffffffffffffea RBX: ffff888292e41000 RCX: f2702d8b8be15100
  [530.784] RDX: ffff88885fda6fb8 RSI: ffff88885fd973c8 RDI: ffff88885fd973c8
  [530.800] RBP: ffff888292e410d0 R08: ffffffff82fd7fd0 R09: 00000000fffeffff
  [530.816] R10: ffffffff82e57fd0 R11: ffffffff82e57d70 R12: 0000000000000000
  [530.832] R13: 0000000000001000 R14: 0000000000001000 R15: ffffc9002c2f76f0
  [530.848] FS:  00007f38d64af000(0000) GS:ffff88885fd80000(0000) knlGS:0000000000000000
  [530.866] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [530.880] CR2: 0000000000000002 CR3: 00000002b6770004 CR4: 00000000003706e0
  [530.896] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [530.912] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [530.928] Call Trace:
  [530.934]  ? btrfs_printk+0x13b/0x18c
  [530.943]  ? btrfs_bio_counter_inc_blocked+0x3d/0x130
  [530.955]  btrfs_map_bio+0x75/0x330
  [530.963]  ? kmem_cache_alloc+0x12a/0x2d0
  [530.973]  ? btrfs_submit_metadata_bio+0x63/0x100
  [530.984]  btrfs_submit_metadata_bio+0xa4/0x100
  [530.995]  submit_extent_page+0x30f/0x360
  [531.004]  read_extent_buffer_pages+0x49e/0x6d0
  [531.015]  ? submit_extent_page+0x360/0x360
  [531.025]  btree_read_extent_buffer_pages+0x5f/0x150
  [531.037]  read_tree_block+0x37/0x60
  [531.046]  read_block_for_search+0x18b/0x410
  [531.056]  btrfs_search_old_slot+0x198/0x2f0
  [531.066]  resolve_indirect_ref+0xfe/0x6f0
  [531.076]  ? ulist_alloc+0x31/0x60
  [531.084]  ? kmem_cache_alloc_trace+0x12e/0x2b0
  [531.095]  find_parent_nodes+0x720/0x1830
  [531.105]  ? ulist_alloc+0x10/0x60
  [531.113]  iterate_extent_inodes+0xea/0x370
  [531.123]  ? btrfs_previous_extent_item+0x8f/0x110
  [531.134]  ? btrfs_search_path_in_tree+0x240/0x240
  [531.146]  iterate_inodes_from_logical+0x98/0xd0
  [531.157]  ? btrfs_search_path_in_tree+0x240/0x240
  [531.168]  btrfs_ioctl_logical_to_ino+0xd9/0x180
  [531.179]  btrfs_ioctl+0xe2/0x2eb0

This occurs when logical inode resolution takes a tree mod log sequence
number, and then while backref walking hits a rewind on a busy node
which has the following sequence of tree mod log operations (numbers
filled in from a specific example, but they are somewhat arbitrary)

  REMOVE_WHILE_FREEING slot 532
  REMOVE_WHILE_FREEING slot 531
  REMOVE_WHILE_FREEING slot 530
  ...
  REMOVE_WHILE_FREEING slot 0
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0
  ADD slot 455
  ADD slot 454
  ADD slot 453
  ...
  ADD slot 0
  MOVE src slot 0 -> dst slot 456 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0

When this sequence gets applied via btrfs_tree_mod_log_rewind, it
allocates a fresh rewind eb, and first inserts the correct key info for
the 533 elements, then overwrites the first 456 of them, then decrements
the count by 456 via the add ops, then rewinds the move by doing a
memmove from 456:988->0:532. We have never written anything past 532, so
that memmove writes garbage into the 0:532 range. In practice, this
results in a lot of fully 0 keys. The rewind then puts valid keys into
slots 0:455 with the last removes, but 456:532 are still invalid.

When search_old_slot uses this eb, if it uses one of those invalid
slots, it can then read the extent buffer and issue a bio for offset 0
which ultimately panics looking up extent mappings.

This bad tree mod log sequence gets generated when the node balancing
code happens to do a balance_node_right followed by a push_node_left
while logging in the tree mod log. Illustrated for ebs L and R (left and
right):

	L                 R
  start:
  [XXX|YYY|...]      [ZZZ|...|...]
  balance_node_right:
  [XXX|YYY|...]      [...|ZZZ|...] move Z to make room for Y
  [XXX|...|...]      [YYY|ZZZ|...] copy Y from L to R
  push_node_left:
  [XXX|YYY|...]      [...|ZZZ|...] copy Y from R to L
  [XXX|YYY|...]      [ZZZ|...|...] move Z into emptied space (NOT LOGGED!)

This is because balance_node_right logs a move, but push_node_left
explicitly doesn't. That is because logging the move would remove the
overwritten src < dst range in the right eb, which was already logged
when we called btrfs_tree_mod_log_eb_copy. The correct sequence would
include a move from 456:988 to 0:532 after remove 0:455 and before
removing 0:532. Reversing that sequence would entail creating keys for
0:532, then moving those keys out to 456:988, then creating more keys
for 0:455.

i.e.,

  REMOVE_WHILE_FREEING slot 532
  REMOVE_WHILE_FREEING slot 531
  REMOVE_WHILE_FREEING slot 530
  ...
  REMOVE_WHILE_FREEING slot 0
  MOVE src slot 456 -> dst slot 0 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0
  ADD slot 455
  ADD slot 454
  ADD slot 453
  ...
  ADD slot 0
  MOVE src slot 0 -> dst slot 456 nritems 533
  REMOVE slot 455
  REMOVE slot 454
  REMOVE slot 453
  ...
  REMOVE slot 0

Fix this to log the move but avoid the double remove by putting all the
logging logic in btrfs_tree_mod_log_eb_copy which has enough information
to detect these cases and properly log moves, removes, and adds. Leave
btrfs_tree_mod_log_insert_move to handle insert_ptr and delete_ptr's
tree mod logging.

(Un)fortunately, this is quite difficult to reproduce, and I was only
able to reproduce it by adding sleeps in btrfs_search_old_slot that
would encourage more log rewinding during ino_to_logical ioctls. I was
able to hit the warning in the previous patch in the series without the
fix quite quickly, but not after this patch.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:34 +02:00
Josef Bacik
016f9d0b74 btrfs: rename del_ptr to btrfs_del_ptr and export it
This exists internal to ctree.c, however btrfs check needs to use it for
some of its operations.  I'd rather not duplicate that code inside of
btrfs check as this is low level and I want to keep this code in one
place, so rename the function to btrfs_del_ptr and export it so that it
can be used inside of btrfs-progs safely.  Add a comment to make sure
this doesn't get removed by a future cleanup.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:25 +02:00
Josef Bacik
b3cbfb0dd4 btrfs: add a btrfs_csum_type_size helper
This is needed in btrfs-progs for the tools that convert the checksum
types for file systems and a few other things.  We don't have it in the
kernel as we just want to get the size for the super blocks type.
However I don't want to have to manually add this every time we sync
ctree.c into btrfs-progs, so add the helper in the kernel with a note so
it doesn't get removed by a later cleanup.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:25 +02:00
Josef Bacik
4aec05fa5a btrfs: remove level argument from btrfs_set_block_flags
We just pass in btrfs_header_level(eb) for the level, and we're passing
in the eb already, so simply get the level from the eb inside of
btrfs_set_block_flags.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:24 +02:00
Qu Wenruo
eee3b81178 btrfs: improve leaf dump and error handling
Improve the leaf dump behavior by:

- Always dump the leaf first, then the error message

- Output the slot number if possible
  Especially in __btrfs_free_extent() the leaf dump of extent tree can
  be pretty large.
  With an extra slot number it's much easier to locate the problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:23 +02:00
Qu Wenruo
6c75a589cb btrfs: print-tree: pass const extent buffer pointer
Since print-tree infrastructure only prints the content of a tree block,
we can make them to accept const extent buffer pointer.

This removes a forced type convert in extent-tree, where we convert a
const extent buffer pointer to regular one, just to avoid compiler
warning.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:22 +02:00
Filipe Manana
88ad95b055 btrfs: tag as unlikely the key comparison when checking sibling keys
When checking siblings keys, before moving keys from one node/leaf to a
sibling node/leaf, it's very unexpected to have the last key of the left
sibling greater than or equals to the first key of the right sibling, as
that means we have a (serious) corruption that breaks the key ordering
properties of a b+tree. Since this is unexpected, surround the comparison
with the unlikely macro, which helps the compiler generate better code
for the most expected case (no existing b+tree corruption). This is also
what we do for other unexpected cases of invalid key ordering (like at
btrfs_set_item_key_safe()).

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:22 +02:00
Filipe Manana
f469c8bd90 btrfs: unexport btrfs_prev_leaf()
btrfs_prev_leaf() is not used outside ctree.c, so there's no need to
export it at ctree.h - just make it static at ctree.c and move its
definition above btrfs_search_slot_for_read(), since that function
calls it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:22 +02:00
Filipe Manana
a2cea677db btrfs: print extent buffers when sibling keys check fails
When trying to move keys from one node/leaf to another sibling node/leaf,
if the sibling keys check fails we just print an error message with the
last key of the left sibling and the first key of the right sibling.
However it's also useful to print all the keys of each sibling, as it
may provide some clues to what went wrong, which code path may be
inserting keys in an incorrect order. So just do that, print the siblings
with btrfs_print_tree(), as it works for both leaves and nodes.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-28 16:36:39 +02:00
Filipe Manana
9ae5afd02a btrfs: abort transaction when sibling keys check fails for leaves
If the sibling keys check fails before we move keys from one sibling
leaf to another, we are not aborting the transaction - we leave that to
some higher level caller of btrfs_search_slot() (or anything else that
uses it to insert items into a b+tree).

This means that the transaction abort will provide a stack trace that
omits the b+tree modification call chain. So change this to immediately
abort the transaction and therefore get a more useful stack trace that
shows us the call chain in the bt+tree modification code.

It's also important to immediately abort the transaction just in case
some higher level caller is not doing it, as this indicates a very
serious corruption and we should stop the possibility of doing further
damage.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-28 16:36:37 +02:00