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Author SHA1 Message Date
Filipe Manana
cab0d8623f btrfs: avoid create and commit empty transaction when committing super
At btrfs_commit_super(), called in a few contexts such as when unmounting
a filesystem, we use btrfs_join_transaction() to catch any running
transaction and then commit it. This will however create a new and empty
transaction in case there's no running transaction or there's a running
transaction with a state >= TRANS_STATE_UNBLOCKED.

As we just want to be sure that any existing transaction is fully
committed, we can use btrfs_attach_transaction_barrier() instead of
btrfs_join_transaction(), therefore avoiding the creation and commit of
empty transactions, which only waste IO and causes rotation of the
precious backup roots.

Example where we create and commit a pointless empty transaction:

  $ mkfs.btrfs -f /dev/sdj
  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            6

  $ mount /dev/sdj /mnt/sdj
  $ touch /mnt/sdj/foo

  # Commit the currently open transaction. Just 'sync' or wait ~30
  # seconds for the transaction kthread to commit it.
  $ sync

  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            7

  $ umount /mnt/sdj

  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            8

The transaction with id 8 was pointless, an empty transaction that did
not achieve anything.

Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2024-07-11 15:33:19 +02:00
Filipe Manana
de18fba807 btrfs: qgroup: avoid start/commit empty transaction when flushing reservations
When flushing reservations we are using btrfs_join_transaction() to get a
handle for the current transaction and then commit it to try to release
space. However btrfs_join_transaction() has some undesirable consequences:

1) If there's no running transaction, it will create one, and we will
   commit it right after. This is unnecessary because it will not release
   any space, and it will result in unnecessary IO and rotation of backup
   roots in the superblock;

2) If there's a current transaction and that transaction is committing
   (its state is >= TRANS_STATE_COMMIT_DOING), it will wait for that
   transaction to almost finish its commit (for its state to be >=
   TRANS_STATE_UNBLOCKED) and then start and return a new transaction.

   We will then commit that new transaction, which is pointless because
   all we wanted was to wait for the current (previous) transaction to
   fully finish its commit (state == TRANS_STATE_COMPLETED), and by
   starting and committing a new transaction we are wasting IO too and
   causing unnecessary rotation of backup roots in the superblock.

So improve this by using btrfs_attach_transaction_barrier() instead, which
does not create a new transaction if there's none running, and if there's
a current transaction that is committing, it will wait for it to fully
commit and not create a new transaction.

Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2024-07-11 15:33:19 +02:00
David Sterba
42317ab440 btrfs: simplify range parameters of btrfs_wait_ordered_roots()
The range is specified only in two ways, we can simplify the case for
the whole filesystem range as a NULL block group parameter.

Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
Qu Wenruo
839d6ea4f8 btrfs: automatically remove the subvolume qgroup
Currently if we fully clean a subvolume (not only delete its directory,
but fully clean all it's related data and root item), the associated
qgroup would not be removed.

We have "btrfs qgroup clear-stale" to handle such 0 level qgroups.

Change the behavior to automatically removie the qgroup of a fully
cleaned subvolume when possible:

- Full qgroup but still consistent
  We can and should remove the qgroup.
  The qgroup numbers should be 0, without any rsv.

- Full qgroup but inconsistent
  Can happen with drop_subtree_threshold feature (skip accounting
  and mark qgroup inconsistent).

  We can and should remove the qgroup.
  Higher level qgroup numbers will be incorrect, but since qgroup
  is already inconsistent, it should not be a problem.

- Squota mode
  This is the special case, we can only drop the qgroup if its numbers
  are all 0.

  This would be handled by can_delete_qgroup(), so we only need to check
  the return value and ignore the -EBUSY error.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1222847
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
Qu Wenruo
a776bf5f3c btrfs: slightly loosen the requirement for qgroup removal
[BUG]
Currently if one is utilizing "qgroups/drop_subtree_threshold" sysfs,
and a snapshot with level higher than that value is dropped, we will
not be able to delete the qgroup until next qgroup rescan:

  uuid=ffffffff-eeee-dddd-cccc-000000000000

  wipefs -fa $dev
  mkfs.btrfs -f $dev -O quota -s 4k -n 4k -U $uuid
  mount $dev $mnt

  btrfs subvolume create $mnt/subv1/
  for (( i = 0; i < 1024; i++ )); do
  	xfs_io -f -c "pwrite 0 2k" $mnt/subv1/file_$i > /dev/null
  done
  sync
  btrfs subvolume snapshot $mnt/subv1 $mnt/snapshot
  btrfs quota enable $mnt
  btrfs quota rescan -w $mnt
  sync
  echo 1 > /sys/fs/btrfs/$uuid/qgroups/drop_subtree_threshold
  btrfs subvolume delete $mnt/snapshot
  btrfs subvolume sync $mnt
  btrfs qgroup show -prce --sync $mnt
  btrfs qgroup destroy 0/257 $mnt
  umount $mnt

The final qgroup removal would fail with the following error:

  ERROR: unable to destroy quota group: Device or resource busy

[CAUSE]
The above script would generate a subvolume of level 2, then snapshot
it, enable qgroup, set the drop_subtree_threshold, then drop the
snapshot.

Since the subvolume drop would meet the threshold, qgroup would be
marked inconsistent and skip accounting to avoid hanging the system at
transaction commit.

But currently we do not allow a qgroup with any rfer/excl numbers to be
dropped, and this is not really compatible with the new
drop_subtree_threshold behavior.

[FIX]
Only require the strict zero rfer/excl/rfer_cmpr/excl_cmpr for squota
mode.  This is due to the fact that squota can never go inconsistent,
and it can have dropped subvolume but with non-zero qgroup numbers for
future accounting.

For full qgroup mode, we only check if there is a subvolume for it.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
David Sterba
56e6f26875 btrfs: constify parameters of write_eb_member() and its users
Reported by 'gcc -Wcast-qual', the argument from which write_extent_buffer()
reads data to write to the eb should be const. In addition the const
needs to be also added to __write_extent_buffer() local buffers.

All callers of write_eb_member() can now be updated to use const for the
input buffer structure or type.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
David Sterba
840a97bdef btrfs: keep const when returning value from get_unaligned_le8()
This was reported by 'gcc -Wcast-qual', the get_unaligned_le8() simply
returns the argument and there's no reason to drop the cast.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
David Sterba
5100c4eb52 btrfs: remove unused define EXTENT_SIZE_PER_ITEM
This was added  in c61a16a701 ("Btrfs: fix the confusion between
delalloc bytes and metadata bytes") and removed in 03fe78cc29
("btrfs: use delalloc_bytes to determine flush amount for
shrink_delalloc") where the calculation was reworked to use a
non-constant numbers. This was found by 'make W=2'.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
David Sterba
d2715d1db4 btrfs: use for-local variables that shadow function variables
We've started to use for-loop local variables and in a few places this
shadows a function variable. Convert a few cases reported by 'make W=2'.
If applicable also change the style to post-increment, that's the
preferred one.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
David Sterba
91629e6dea btrfs: rename macro local variables that clash with other variables
Fix variable names in two macros where there's a local function variable
of the same name.  In subpage_calc_start_bit() it's in several callers,
in btrfs_abort_transaction() it's only in replace_file_extents().
Found by 'make W=2'.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
David Sterba
9c5e1fb024 btrfs: remove duplicate name variable declarations
When running 'make W=2' there are a few reports where a variable of the
same name is declared in a nested block. In all the cases we can use the
one declared in the parent block, no problematic cases were found.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
Filipe Manana
56b7169f69 btrfs: use a btrfs_inode local variable at btrfs_sync_file()
Instead of using a VFS inode local pointer and then doing many BTRFS_I()
calls inside btrfs_sync_file(), use a btrfs_inode pointer instead. This
makes everything a bit easier to read and less confusing, allowing to
make some statements shorter.

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>
2024-07-11 15:33:18 +02:00
Filipe Manana
e641e323ab btrfs: pass a btrfs_inode to btrfs_wait_ordered_range()
Instead of passing a (VFS) inode pointer argument, pass a btrfs_inode
instead, as this is generally what we do for internal APIs, making it
more consistent with most of the code base. This will later allow to
help to remove a lot of BTRFS_I() calls in btrfs_sync_file().

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>
2024-07-11 15:33:18 +02:00
Filipe Manana
cef2daba42 btrfs: pass a btrfs_inode to btrfs_fdatawrite_range()
Instead of passing a (VFS) inode pointer argument, pass a btrfs_inode
instead, as this is generally what we do for internal APIs, making it
more consistent with most of the code base. This will later allow to
help to remove a lot of BTRFS_I() calls in btrfs_sync_file().

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>
2024-07-11 15:33:18 +02:00
Filipe Manana
4d0120a519 btrfs: use a btrfs_inode in the log context (struct btrfs_log_ctx)
Instead of using a inode pointer, use a btrfs_inode pointer in the log
context structure, as this is generally what we need and allows for some
internal APIs to take a btrfs_inode instead, making them more consistent
with most of the code base. This will later allow to help to remove a lot
of BTRFS_I() calls in btrfs_sync_file().

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>
2024-07-11 15:33:18 +02:00
Filipe Manana
c41881ae07 btrfs: make btrfs_finish_ordered_extent() return void
Currently btrfs_finish_ordered_extent() returns a boolean indicating if
the ordered extent was added to the work queue for completion, but none
of its callers cares about it, so make it return void.

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>
2024-07-11 15:33:18 +02:00
Anand Jain
83937fb612 btrfs: move btrfs_block_group_root() to block-group.c
The function btrfs_block_group_root() is declared in disk-io.c; however,
all its callers are in block-group.c. Move it to the latter file and
declare it static.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
Anand Jain
70559abf62 btrfs: drop bytenr_orig and fix comment in btrfs_scan_one_device()
Drop the single-use variable bytenr_orig and instead use btrfs_sb_offset()
in the function argument passing.

Fix a stale comment about not automatically fixing a bad primary
superblock from the backup mirror copies. Also, move the comment closer
to where the primary superblock read occurs.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
Filipe Manana
4e660ca3a9 btrfs: use a regular rb_root instead of cached rb_root for extent_map_tree
We are currently using a cached rb_root (struct rb_root_cached) for the
rb root of struct extent_map_tree. This doesn't offer much of an advantage
here because:

1) It's only advantage over the regular rb_root is that it caches a
   pointer to the left most node (first node), so a call to
   rb_first_cached() doesn't have to chase pointers until it reaches
   the left most node;

2) We only have two scenarios that access left most node with
   rb_first_cached():

      When dropping all extent maps from an inode, during inode eviction;

      When iterating over extent maps during the extent map shrinker;

3) In both cases we keep removing extent maps, which causes deletion of
   the left most node so rb_erase_cached() has to call rb_next() to find
   out what's the next left most node and assign it to
   struct rb_root_cached::rb_leftmost;

4) We can do that ourselves in those two uses cases and stop using a
   rb_root_cached rb tree and use instead a regular rb_root rb tree.

   This reduces the size of struct extent_map_tree by 8 bytes and, since
   this structure is embedded in struct btrfs_inode, it also reduces the
   size of that structure by 8 bytes.

   So on a 64 bits platform the size of btrfs_inode is reduced from 1032
   bytes down to 1024 bytes.

   This means we will be able to have 4 inodes per 4K page instead of 3.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:18 +02:00
Filipe Manana
7f5830bc96 btrfs: rename rb_root member of extent_map_tree from map to root
Currently we name the rb_root member of struct extent_map_tree as 'map',
which is odd and confusing. Since it's a root node, rename it to 'root'.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
7a7bc21449 btrfs: remove objectid from struct btrfs_inode on 64 bits platforms
On 64 bits platforms we don't really need to have a dedicated member (the
objectid field) for the inode's number since we store in the VFS inode's
i_ino member, which is an unsigned long and this type is 64 bits wide on
64 bits platforms. We only need that field in case we are on a 32 bits
platform because the unsigned long type is 32 bits wide on such platforms
See commit 33345d0152 ("Btrfs: Always use 64bit inode number") regarding
this 64/32 bits detail.

The objectid field of struct btrfs_inode is also used to store the ID of
a root for directories that are stubs for unreferenced roots. In such
cases the inode is a directory and has the BTRFS_INODE_ROOT_STUB runtime
flag set.

So in order to reduce the size of btrfs_inode structure on 64 bits
platforms we can remove the objectid member and use the VFS inode's i_ino
member instead whenever we need to get the inode number. In case the inode
is a root stub (BTRFS_INODE_ROOT_STUB set) we can use the member
last_reflink_trans to store the ID of the unreferenced root, since such
inode is a directory and reflinks can't be done against directories.

So remove the objectid fields for 64 bits platforms and alias the
last_reflink_trans field with a name of ref_root_id in a union.
On a release kernel config, this reduces the size of struct btrfs_inode
from 1040 bytes down to 1032 bytes.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
068fc8f914 btrfs: remove location key from struct btrfs_inode
Currently struct btrfs_inode has a key member, named "location", that is
either:

1) The key of the inode's item. In this case the objectid is the number
   of the inode;

2) A key stored in a dir entry with a type of BTRFS_ROOT_ITEM_KEY, for
   the case where we have a root that is a snapshot of a subvolume that
   points to other subvolumes. In this case the objectid is the ID of
   a subvolume inside the snapshotted parent subvolume.

The key is only used to lookup the inode item for the first case, while
for the second it's never used since it corresponds to directory stubs
created with new_simple_dir() and which are marked as dummy, so there's
no actual inode item to ever update. In the second case we only check
the key type at btrfs_ino() for 32 bits platforms and its objectid is
only needed for unlink.

Instead of using a key we can do fine with just the objectid, since we
can generate the key whenever we need it having only the objectid, as
in all use cases the type is always BTRFS_INODE_ITEM_KEY and the offset
is always 0.

So use only an objectid instead of a full key. This reduces the size of
struct btrfs_inode from 1048 bytes down to 1040 bytes on a release kernel.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
3d7db6e8bd btrfs: don't allocate file extent tree for non regular files
When not using the NO_HOLES feature we always allocate an io tree for an
inode's file_extent_tree. This is wasteful because that io tree is only
used for regular files, so we allocate more memory than needed for inodes
that represent directories or symlinks for example, or for inodes that
correspond to free space inodes.

So improve on this by allocating the io tree only for inodes of regular
files that are not free space inodes.

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>
2024-07-11 15:33:17 +02:00
Filipe Manana
d9891ae28b btrfs: unify index_cnt and csum_bytes from struct btrfs_inode
The index_cnt field of struct btrfs_inode is used only for two purposes:

1) To store the index for the next entry added to a directory;

2) For the data relocation inode to track the logical start address of the
   block group currently being relocated.

For the relocation case we use index_cnt because it's not used for
anything else in the relocation use case - we could have used other fields
that are not used by relocation such as defrag_bytes, last_unlink_trans
or last_reflink_trans for example (among others).

Since the csum_bytes field is not used for directories, do the following
changes:

1) Put index_cnt and csum_bytes in a union, and index_cnt is only
   initialized when the inode is a directory. The csum_bytes is only
   accessed in IO paths for regular files, so we're fine here;

2) Use the defrag_bytes field for relocation, since the data relocation
   inode is never used for defrag purposes. And to make the naming better,
   alias it to reloc_block_group_start by using a union.

This reduces the size of struct btrfs_inode by 8 bytes in a release
kernel, from 1056 bytes down to 1048 bytes.

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>
2024-07-11 15:33:17 +02:00
Filipe Manana
e2844cce75 btrfs: remove inode_lock from struct btrfs_root and use xarray locks
Currently we use the spinlock inode_lock from struct btrfs_root to
serialize access to two different data structures:

1) The delayed inodes xarray (struct btrfs_root::delayed_nodes);
2) The inodes xarray (struct btrfs_root::inodes).

Instead of using our own lock, we can use the spinlock that is part of the
xarray implementation, by using the xa_lock() and xa_unlock() APIs and
using the xarray APIs with the double underscore prefix that don't take
the xarray locks and assume the caller is using xa_lock() and xa_unlock().

So remove the spinlock inode_lock from struct btrfs_root and use the
corresponding xarray locks. This brings 2 benefits:

1) We reduce the size of struct btrfs_root, from 1336 bytes down to
   1328 bytes on a 64 bits release kernel config;

2) We reduce lock contention by not using anymore the same lock for
   changing two different and unrelated xarrays.

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>
2024-07-11 15:33:17 +02:00
Filipe Manana
d25f4ec176 btrfs: reduce nesting and deduplicate error handling at btrfs_iget_path()
Make btrfs_iget_path() simpler and easier to read by avoiding nesting of
if-then-else statements and having an error label to do all the error
handling instead of repeating it a couple times.

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>
2024-07-11 15:33:17 +02:00
Filipe Manana
061ea8581b btrfs: preallocate inodes xarray entry to avoid transaction abort
When creating a new inode, at btrfs_create_new_inode(), one of the very
last steps is to add the inode to the root's inodes xarray. This often
requires allocating memory which may fail (even though xarrays have a
dedicated kmem_cache which make it less likely to fail), and at that point
we are forced to abort the current transaction (as some, but not all, of
the inode metadata was added to its subvolume btree).

To avoid a transaction abort, preallocate memory for the xarray early at
btrfs_create_new_inode(), so that if we fail we don't need to abort the
transaction and the insertion into the xarray is guaranteed to succeed.

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>
2024-07-11 15:33:17 +02:00
Filipe Manana
310b2f5d5a btrfs: use an xarray to track open inodes in a root
Currently we use a red black tree (rb-tree) to track the currently open
inodes of a root (in struct btrfs_root::inode_tree). This however is not
very efficient when the number of inodes is large since rb-trees are
binary trees. For example for 100K open inodes, the tree has a depth of
17. Besides that, inserting into the tree requires navigating through it
and pulling useless cache lines in the process since the red black tree
nodes are embedded within the btrfs inode - on the other hand, by being
embedded, it requires no extra memory allocations.

We can improve this by using an xarray instead, which is efficient when
indices are densely clustered (such as inode numbers), is more cache
friendly and behaves like a resizable array, with a much better search
and insertion complexity than a red black tree. This only has one small
disadvantage which is that insertion will sometimes require allocating
memory for the xarray - which may fail (not that often since it uses a
kmem_cache) - but on the other hand we can reduce the btrfs inode
structure size by 24 bytes (from 1080 down to 1056 bytes) after removing
the embedded red black tree node, which after the next patches will allow
to reduce the size of the structure to 1024 bytes, meaning we will be able
to store 4 inodes per 4K page instead of 3 inodes.

This change does a straightforward change to use an xarray, and results
in a transaction abort if we can't allocate memory for the xarray when
creating an inode - but the next patch changes things so that we don't
need to abort.

Running the following fs_mark test showed some improvements:

    $ cat test.sh
    #!/bin/bash

    DEV=/dev/nullb0
    MNT=/mnt/nullb0
    MOUNT_OPTIONS="-o ssd"
    FILES=100000
    THREADS=$(nproc --all)

    echo "performance" | \
        tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

    mkfs.btrfs -f $DEV
    mount $MOUNT_OPTIONS $DEV $MNT

    OPTS="-S 0 -L 5 -n $FILES -s 0 -t $THREADS -k"
    for ((i = 1; i <= $THREADS; i++)); do
        OPTS="$OPTS -d $MNT/d$i"
    done

    fs_mark $OPTS

    umount $MNT

Before this patch:

    FSUse%        Count         Size    Files/sec     App Overhead
        10      1200000            0      92081.6         12505547
        16      2400000            0     138222.6         13067072
        23      3600000            0     148833.1         13290336
        43      4800000            0      97864.7         13931248
        53      6000000            0      85597.3         14384313

After this patch:

    FSUse%        Count         Size    Files/sec     App Overhead
        10      1200000            0      93225.1         12571078
        16      2400000            0     146720.3         12805007
        23      3600000            0     160626.4         13073835
        46      4800000            0     116286.2         13802927
        53      6000000            0      90087.9         14754892

The test was run with a release kernel config (Debian's default config).

Also capturing the insertion times into the rb tree and into the xarray,
that is measuring the duration of the old function inode_tree_add() and
the duration of the new btrfs_add_inode_to_root() function, gave the
following results (in nanoseconds):

Before this patch, inode_tree_add() execution times:

   Count: 5000000
   Range:  0.000 - 5536887.000; Mean: 775.674; Median: 729.000; Stddev: 4820.961
   Percentiles:  90th: 1015.000; 95th: 1139.000; 99th: 1397.000
         0.000 -       7.816:      40 |
         7.816 -      37.858:     209 |
        37.858 -     170.278:    6059 |
       170.278 -     753.961: 2754890 #####################################################
       753.961 -    3326.728: 2232312 ###########################################
      3326.728 -   14667.018:    4366 |
     14667.018 -   64652.943:     852 |
     64652.943 -  284981.761:     550 |
    284981.761 - 1256150.914:     221 |
   1256150.914 - 5536887.000:       7 |

After this patch, btrfs_add_inode_to_root() execution times:

   Count: 5000000
   Range:  0.000 - 2900652.000; Mean: 272.148; Median: 241.000; Stddev: 2873.369
   Percentiles:  90th: 342.000; 95th: 432.000; 99th: 572.000
        0.000 -       7.264:     104 |
        7.264 -      33.145:     352 |
       33.145 -     140.081:  109606 #
      140.081 -     581.930: 4840090 #####################################################
      581.930 -    2407.590:   43532 |
     2407.590 -    9950.979:    2245 |
     9950.979 -   41119.278:     514 |
    41119.278 -  169902.616:     155 |
   169902.616 -  702018.539:      47 |
   702018.539 - 2900652.000:       9 |

Average, percentiles, standard deviation, etc, are all much better.

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>
2024-07-11 15:33:17 +02:00
Qu Wenruo
bbbee460aa btrfs: raid56: do extra dumping for CONFIG_BTRFS_ASSERT
There are several hard-to-hit ASSERT()s hit inside raid56.
Unfortunately the ASSERT() expression is a little complex, and except
the ASSERT(), there is nothing to provide any clue.

Considering if race is involved, it's pretty hard to reproduce.
Meanwhile sometimes the dump of the rbio structure can provide some
pretty good clues, it's worth to do the extra multi-line dump for
btrfs raid56 related code.

The dump looks like this:

  BTRFS critical (device dm-3): bioc logical=4598530048 full_stripe=4598530048 size=0 map_type=0x81 mirror=0 replace_nr_stripes=0 replace_stripe_src=-1 num_stripes=5
  BTRFS critical (device dm-3):     nr=0 devid=1 physical=1166147584
  BTRFS critical (device dm-3):     nr=1 devid=2 physical=1145176064
  BTRFS critical (device dm-3):     nr=2 devid=4 physical=1145176064
  BTRFS critical (device dm-3):     nr=3 devid=5 physical=1145176064
  BTRFS critical (device dm-3):     nr=4 devid=3 physical=1145176064
  BTRFS critical (device dm-3): rbio flags=0x0 nr_sectors=80 nr_data=4 real_stripes=5 stripe_nsectors=16 scrubp=0 dbitmap=0x0
  BTRFS critical (device dm-3): logical=4598530048
  assertion failed: orig_logical >= full_stripe_start && orig_logical + orig_len <= full_stripe_start + rbio->nr_data * BTRFS_STRIPE_LEN, in fs/btrfs/raid56.c:1702

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:16 +02:00
Filipe Manana
3441b070f8 btrfs: fix function name in comment for btrfs_remove_ordered_extent()
Due to a refactoring introduced by commit 53d9981ca2 ("btrfs: split
btrfs_alloc_ordered_extent to allocation and insertion helpers"), the
function btrfs_alloc_ordered_extent() was renamed to
alloc_ordered_extent(), so the comment at btrfs_remove_ordered_extent()
is no longer very accurate. Update the comment to refer to the new
name "alloc_ordered_extent()".

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>
2024-07-11 15:33:16 +02:00
Filipe Manana
416d6ab49d btrfs: fix misspelled end IO compression callbacks
Fix typo in the end IO compression callbacks, from "comprssed" to
"compressed".

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>
2024-07-11 15:33:16 +02:00
Filipe Manana
d153fc5573 btrfs: remove no longer used btrfs_migrate_to_delayed_refs_rsv()
The function btrfs_migrate_to_delayed_refs_rsv() is no longer used.
Its last use was removed in commit 2f6397e448 ("btrfs: don't refill
whole delayed refs block reserve when starting transaction").
So remove the function.

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>
2024-07-11 15:33:16 +02:00
Filipe Manana
55a2f38870 btrfs: zoned: make btrfs_get_dev_zone() static
It's not used outside zoned.c, so make it static.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:16 +02:00
Johannes Thumshirn
3ef6adef12 btrfs: pass struct btrfs_io_geometry into handle_ops_on_dev_replace()
Passing in a 'struct btrfs_io_geometry into handle_ops_on_dev_replace
can reduce the number of arguments by two.

No functional changes otherwise.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:16 +02:00
David Sterba
34064fc3c9 btrfs: qgroup: do quick checks if quotas are enabled before starting ioctls
The ioctls that add relations, create qgroups or set limits start/join
transaction. When quotas are not enabled this is not necessary, there
will be errors reported back anyway but this could be also misleading
and we should really report that quotas are not enabled. For that use
-ENOTCONN.

The helper is meant to do a quick check before any other standard ioctl
checks are done. If quota is disabled meanwhile we still rely on proper
locking inside any active operation changing the qgroup structures.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:16 +02:00
Linus Torvalds
661e504db0 for-6.10-rc6-tag
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Merge tag 'for-6.10-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix folio refcounting when releasing them (encoded write, dummy
   extent buffer)

 - fix out of bounds read when checking qgroup inherit data

 - fix how configurable chunk size is handled in zoned mode

 - in the ref-verify tool, fix uninitialized return value when checking
   extent owner ref and simple quota are not enabled

* tag 'for-6.10-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix folio refcount in __alloc_dummy_extent_buffer()
  btrfs: fix folio refcount in btrfs_do_encoded_write()
  btrfs: fix uninitialized return value in the ref-verify tool
  btrfs: always do the basic checks for btrfs_qgroup_inherit structure
  btrfs: zoned: fix calc_available_free_space() for zoned mode
2024-07-04 10:27:37 -07:00
Boris Burkov
a56c85fa2d btrfs: fix folio refcount in __alloc_dummy_extent_buffer()
Another improper use of __folio_put() in an error path after freshly
allocating pages/folios which returns them with the refcount initialized
to 1. The refactor from __free_pages() -> __folio_put() (instead of
folio_put) removed a refcount decrement found in __free_pages() and
folio_put but absent from __folio_put().

Fixes: 13df3775ef ("btrfs: cleanup metadata page pointer usage")
CC: stable@vger.kernel.org # 6.8+
Tested-by: Ed Tomlinson <edtoml@gmail.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-04 02:19:10 +02:00
Boris Burkov
da0386c1c7 btrfs: fix folio refcount in btrfs_do_encoded_write()
The conversion to folios switched __free_page() to __folio_put() in the
error path in btrfs_do_encoded_write().

However, this gets the page refcounting wrong. If we do hit that error
path (I reproduced by modifying btrfs_do_encoded_write to pretend to
always fail in a way that jumps to out_folios and running the fstests
case btrfs/281), then we always hit the following BUG freeing the folio:

  BUG: Bad page state in process btrfs  pfn:40ab0b
  page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x61be5 pfn:0x40ab0b
   flags: 0x5ffff0000000000(node=0|zone=2|lastcpupid=0x1ffff)
  raw: 05ffff0000000000 0000000000000000 dead000000000122 0000000000000000
  raw: 0000000000061be5 0000000000000000 00000001ffffffff 0000000000000000
  page dumped because: nonzero _refcount
  Call Trace:
  <TASK>
  dump_stack_lvl+0x3d/0xe0
  bad_page+0xea/0xf0
  free_unref_page+0x8e1/0x900
  ? __mem_cgroup_uncharge+0x69/0x90
  __folio_put+0xe6/0x190
  btrfs_do_encoded_write+0x445/0x780
  ? current_time+0x25/0xd0
  btrfs_do_write_iter+0x2cc/0x4b0
  btrfs_ioctl_encoded_write+0x2b6/0x340

It turns out __free_page() decreases the page reference count while
__folio_put() does not. Switch __folio_put() to folio_put() which
decreases the folio reference count first.

Fixes: 400b172b8c ("btrfs: compression: migrate compression/decompression paths to folios")
Tested-by: Ed Tomlinson <edtoml@gmail.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-04 02:18:45 +02:00
Filipe Manana
9da45c88e1 btrfs: fix uninitialized return value in the ref-verify tool
In the ref-verify tool, when processing the inline references of an extent
item, we may end up returning with uninitialized return value, because:

1) The 'ret' variable is not initialized if there are no inline extent
   references ('ptr' == 'end' before the while loop starts);

2) If we find an extent owner inline reference we don't initialize 'ret'.

So fix these cases by initializing 'ret' to 0 when declaring the variable
and set it to -EINVAL if we find an extent owner inline references and
simple quotas are not enabled (as well as print an error message).

Reported-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/59b40ebe-c824-457d-8b24-0bbca69d472b@gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-02 19:14:57 +02:00
Qu Wenruo
724d8042ce btrfs: always do the basic checks for btrfs_qgroup_inherit structure
[BUG]
Syzbot reports the following regression detected by KASAN:

  BUG: KASAN: slab-out-of-bounds in btrfs_qgroup_inherit+0x42e/0x2e20 fs/btrfs/qgroup.c:3277
  Read of size 8 at addr ffff88814628ca50 by task syz-executor318/5171

  CPU: 0 PID: 5171 Comm: syz-executor318 Not tainted 6.10.0-rc2-syzkaller-00010-g2ab795141095 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:88 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
   print_address_description mm/kasan/report.c:377 [inline]
   print_report+0x169/0x550 mm/kasan/report.c:488
   kasan_report+0x143/0x180 mm/kasan/report.c:601
   btrfs_qgroup_inherit+0x42e/0x2e20 fs/btrfs/qgroup.c:3277
   create_pending_snapshot+0x1359/0x29b0 fs/btrfs/transaction.c:1854
   create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1922
   btrfs_commit_transaction+0xf20/0x3740 fs/btrfs/transaction.c:2382
   create_snapshot+0x6a1/0x9e0 fs/btrfs/ioctl.c:875
   btrfs_mksubvol+0x58f/0x710 fs/btrfs/ioctl.c:1029
   btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1075
   __btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1340
   btrfs_ioctl_snap_create_v2+0x1f2/0x3a0 fs/btrfs/ioctl.c:1422
   btrfs_ioctl+0x99e/0xc60
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:907 [inline]
   __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  RIP: 0033:0x7fcbf1992509
  RSP: 002b:00007fcbf1928218 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00007fcbf1a1f618 RCX: 00007fcbf1992509
  RDX: 0000000020000280 RSI: 0000000050009417 RDI: 0000000000000003
  RBP: 00007fcbf1a1f610 R08: 00007ffea1298e97 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcbf19eb660
  R13: 00000000200002b8 R14: 00007fcbf19e60c0 R15: 0030656c69662f2e
   </TASK>

And it also pinned it down to commit b5357cb268 ("btrfs: qgroup: do not
check qgroup inherit if qgroup is disabled").

[CAUSE]
That offending commit skips the whole qgroup inherit check if qgroup is
not enabled.

But that also skips the very basic checks like
num_ref_copies/num_excl_copies and the structure size checks.

Meaning if a qgroup enable/disable race is happening at the background,
and we pass a btrfs_qgroup_inherit structure when the qgroup is
disabled, the check would be completely skipped.

Then at the time of transaction commitment, qgroup is re-enabled and
btrfs_qgroup_inherit() is going to use the incorrect structure and
causing the above KASAN error.

[FIX]
Make btrfs_qgroup_check_inherit() only skip the source qgroup checks.
So that even if invalid btrfs_qgroup_inherit structure is passed in, we
can still reject invalid ones no matter if qgroup is enabled or not.

Furthermore we do already have an extra safety inside
btrfs_qgroup_inherit(), which would just ignore invalid qgroup sources,
so even if we only skip the qgroup source check we're still safe.

Reported-by: syzbot+a0d1f7e26910be4dc171@syzkaller.appspotmail.com
Fixes: b5357cb268 ("btrfs: qgroup: do not check qgroup inherit if qgroup is disabled")
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-02 19:14:36 +02:00
Naohiro Aota
64d2c847ba btrfs: zoned: fix calc_available_free_space() for zoned mode
calc_available_free_space() returns the total size of metadata (or
system) block groups, which can be allocated from unallocated disk
space. The logic is wrong on zoned mode in two places.

First, the calculation of data_chunk_size is wrong. We always allocate
one zone as one chunk, and no partial allocation of a zone. So, we
should use zone_size (= data_sinfo->chunk_size) as it is.

Second, the result "avail" may not be zone aligned. Since we always
allocate one zone as one chunk on zoned mode, returning non-zone size
aligned bytes will result in less pressure on the async metadata reclaim
process.

This is serious for the nearly full state with a large zone size device.
Allowing over-commit too much will result in less async reclaim work and
end up in ENOSPC. We can align down to the zone size to avoid that.

Fixes: cb6cbab790 ("btrfs: adjust overcommit logic when very close to full")
CC: stable@vger.kernel.org # 6.9
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-02 19:13:11 +02:00
Linus Torvalds
cfbc0ffea8 for-6.10-rc6-tag
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Merge tag 'for-6.10-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "A fixup for a recent fix that prevents an infinite loop during block
  group reclaim.

  Unfortunately it introduced an unsafe way of updating block group list
  and could race with relocation. This could be hit on fast devices when
  relocation/balance does not have enough space"

* tag 'for-6.10-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix adding block group to a reclaim list and the unused list during reclaim
2024-07-01 12:48:28 -07:00
Naohiro Aota
48f091fd50 btrfs: fix adding block group to a reclaim list and the unused list during reclaim
There is a potential parallel list adding for retrying in
btrfs_reclaim_bgs_work and adding to the unused list. Since the block
group is removed from the reclaim list and it is on a relocation work,
it can be added into the unused list in parallel. When that happens,
adding it to the reclaim list will corrupt the list head and trigger
list corruption like below.

Fix it by taking fs_info->unused_bgs_lock.

  [177.504][T2585409] BTRFS error (device nullb1): error relocating ch= unk 2415919104
  [177.514][T2585409] list_del corruption. next->prev should be ff1100= 0344b119c0, but was ff11000377e87c70. (next=3Dff110002390cd9c0)
  [177.529][T2585409] ------------[ cut here ]------------
  [177.537][T2585409] kernel BUG at lib/list_debug.c:65!
  [177.545][T2585409] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
  [177.555][T2585409] CPU: 9 PID: 2585409 Comm: kworker/u128:2 Tainted: G        W          6.10.0-rc5-kts #1
  [177.568][T2585409] Hardware name: Supermicro SYS-520P-WTR/X12SPW-TF, BIOS 1.2 02/14/2022
  [177.579][T2585409] Workqueue: events_unbound btrfs_reclaim_bgs_work[btrfs]
  [177.589][T2585409] RIP: 0010:__list_del_entry_valid_or_report.cold+0x70/0x72
  [177.624][T2585409] RSP: 0018:ff11000377e87a70 EFLAGS: 00010286
  [177.633][T2585409] RAX: 000000000000006d RBX: ff11000344b119c0 RCX:0000000000000000
  [177.644][T2585409] RDX: 000000000000006d RSI: 0000000000000008 RDI:ffe21c006efd0f40
  [177.655][T2585409] RBP: ff110002e0509f78 R08: 0000000000000001 R09:ffe21c006efd0f08
  [177.665][T2585409] R10: ff11000377e87847 R11: 0000000000000000 R12:ff110002390cd9c0
  [177.676][T2585409] R13: ff11000344b119c0 R14: ff110002e0508000 R15:dffffc0000000000
  [177.687][T2585409] FS:  0000000000000000(0000) GS:ff11000fec880000(0000) knlGS:0000000000000000
  [177.700][T2585409] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [177.709][T2585409] CR2: 00007f06bc7b1978 CR3: 0000001021e86005 CR4:0000000000771ef0
  [177.720][T2585409] DR0: 0000000000000000 DR1: 0000000000000000 DR2:0000000000000000
  [177.731][T2585409] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:0000000000000400
  [177.742][T2585409] PKRU: 55555554
  [177.748][T2585409] Call Trace:
  [177.753][T2585409]  <TASK>
  [177.759][T2585409]  ? __die_body.cold+0x19/0x27
  [177.766][T2585409]  ? die+0x2e/0x50
  [177.772][T2585409]  ? do_trap+0x1ea/0x2d0
  [177.779][T2585409]  ? __list_del_entry_valid_or_report.cold+0x70/0x72
  [177.788][T2585409]  ? do_error_trap+0xa3/0x160
  [177.795][T2585409]  ? __list_del_entry_valid_or_report.cold+0x70/0x72
  [177.805][T2585409]  ? handle_invalid_op+0x2c/0x40
  [177.812][T2585409]  ? __list_del_entry_valid_or_report.cold+0x70/0x72
  [177.820][T2585409]  ? exc_invalid_op+0x2d/0x40
  [177.827][T2585409]  ? asm_exc_invalid_op+0x1a/0x20
  [177.834][T2585409]  ? __list_del_entry_valid_or_report.cold+0x70/0x72
  [177.843][T2585409]  btrfs_delete_unused_bgs+0x3d9/0x14c0 [btrfs]

There is a similar retry_list code in btrfs_delete_unused_bgs(), but it is
safe, AFAICS. Since the block group was in the unused list, the used bytes
should be 0 when it was added to the unused list. Then, it checks
block_group->{used,reserved,pinned} are still 0 under the
block_group->lock. So, they should be still eligible for the unused list,
not the reclaim list.

The reason it is safe there it's because because we're holding
space_info->groups_sem in write mode.

That means no other task can allocate from the block group, so while we
are at deleted_unused_bgs() it's not possible for other tasks to
allocate and deallocate extents from the block group, so it can't be
added to the unused list or the reclaim list by anyone else.

The bug can be reproduced by btrfs/166 after a few rounds. In practice
this can be hit when relocation cannot find more chunk space and ends
with ENOSPC.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Suggested-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Fixes: 4eb4e85c4f ("btrfs: retry block group reclaim without infinite loop")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-01 17:33:15 +02:00
Linus Torvalds
66e55ff12e for-6.10-rc5-tag
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Merge tag 'for-6.10-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix quota root leak after quota disable failure

 - fix condition when checking if a zone can be added as free

 - allocate inode in NOFS context during logging or tree-log replay

 - handle raid-stripe-tree lookup correctly during scrub

* tag 'for-6.10-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: qgroup: fix quota root leak after quota disable failure
  btrfs: scrub: handle RST lookup error correctly
  btrfs: zoned: fix initial free space detection
  btrfs: use NOFS context when getting inodes during logging and log replay
2024-06-27 10:26:16 -07:00
Filipe Manana
a7e4c6a303 btrfs: qgroup: fix quota root leak after quota disable failure
If during the quota disable we fail when cleaning the quota tree or when
deleting the root from the root tree, we jump to the 'out' label without
ever dropping the reference on the quota root, resulting in a leak of the
root since fs_info->quota_root is no longer pointing to the root (we have
set it to NULL just before those steps).

Fix this by always doing a btrfs_put_root() call under the 'out' label.
This is a problem that exists since qgroups were first added in 2012 by
commit bed92eae26 ("Btrfs: qgroup implementation and prototypes"), but
back then we missed a kfree on the quota root and free_extent_buffer()
calls on its root and commit root nodes, since back then roots were not
yet reference counted.

Reviewed-by: Boris Burkov <boris@bur.io>
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>
2024-06-25 00:35:50 +02:00
Qu Wenruo
2c49908634 btrfs: scrub: handle RST lookup error correctly
[BUG]
When running btrfs/060 with forced RST feature, it would crash the
following ASSERT() inside scrub_read_endio():

	ASSERT(sector_nr < stripe->nr_sectors);

Before that, we would have tree dump from
btrfs_get_raid_extent_offset(), as we failed to find the RST entry for
the range.

[CAUSE]
Inside scrub_submit_extent_sector_read() every time we allocated a new
bbio we immediately called btrfs_map_block() to make sure there was some
RST range covering the scrub target.

But if btrfs_map_block() fails, we immediately call endio for the bbio,
while the bbio is newly allocated, it's completely empty.

Then inside scrub_read_endio(), we go through the bvecs to find
the sector number (as bi_sector is no longer reliable if the bio is
submitted to lower layers).

And since the bio is empty, such bvecs iteration would not find any
sector matching the sector, and return sector_nr == stripe->nr_sectors,
triggering the ASSERT().

[FIX]
Instead of calling btrfs_map_block() after allocating a new bbio, call
btrfs_map_block() first.

Since our only objective of calling btrfs_map_block() is only to update
stripe_len, there is really no need to do that after btrfs_alloc_bio().

This new timing would avoid the problem of handling empty bbio
completely, and in fact fixes a possible race window for the old code,
where if the submission thread is the only owner of the pending_io, the
scrub would never finish (since we didn't decrease the pending_io
counter).

Although the root cause of RST lookup failure still needs to be
addressed.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-06-25 00:34:16 +02:00
Naohiro Aota
b9fd2affe4 btrfs: zoned: fix initial free space detection
When creating a new block group, it calls btrfs_add_new_free_space() to add
the entire block group range into the free space accounting.
__btrfs_add_free_space_zoned() checks if size == block_group->length to
detect the initial free space adding, and proceed that case properly.

However, if the zone_capacity == zone_size and the over-write speed is fast
enough, the entire zone can be over-written within one transaction. That
confuses __btrfs_add_free_space_zoned() to handle it as an initial free
space accounting. As a result, that block group becomes a strange state: 0
used bytes, 0 zone_unusable bytes, but alloc_offset == zone_capacity (no
allocation anymore).

The initial free space accounting can properly be checked by checking
alloc_offset too.

Fixes: 98173255bd ("btrfs: zoned: calculate free space from zone capacity")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-06-25 00:33:57 +02:00
Filipe Manana
d1825752e3 btrfs: use NOFS context when getting inodes during logging and log replay
During inode logging (and log replay too), we are holding a transaction
handle and we often need to call btrfs_iget(), which will read an inode
from its subvolume btree if it's not loaded in memory and that results in
allocating an inode with GFP_KERNEL semantics at the btrfs_alloc_inode()
callback - and this may recurse into the filesystem in case we are under
memory pressure and attempt to commit the current transaction, resulting
in a deadlock since the logging (or log replay) task is holding a
transaction handle open.

Syzbot reported this with the following stack traces:

  WARNING: possible circular locking dependency detected
  6.10.0-rc2-syzkaller-00361-g061d1af7b030 #0 Not tainted
  ------------------------------------------------------
  syz-executor.1/9919 is trying to acquire lock:
  ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:334 [inline]
  ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3891 [inline]
  ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3981 [inline]
  ffffffff8dd3aac0 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_lru_noprof+0x58/0x2f0 mm/slub.c:4020

  but task is already holding lock:
  ffff88804b569358 (&ei->log_mutex){+.+.}-{3:3}, at: btrfs_log_inode+0x39c/0x4660 fs/btrfs/tree-log.c:6481

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&ei->log_mutex){+.+.}-{3:3}:
         __mutex_lock_common kernel/locking/mutex.c:608 [inline]
         __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
         btrfs_log_inode+0x39c/0x4660 fs/btrfs/tree-log.c:6481
         btrfs_log_inode_parent+0x8cb/0x2a90 fs/btrfs/tree-log.c:7079
         btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7180
         btrfs_sync_file+0x9c1/0xe10 fs/btrfs/file.c:1959
         vfs_fsync_range+0x141/0x230 fs/sync.c:188
         generic_write_sync include/linux/fs.h:2794 [inline]
         btrfs_do_write_iter+0x584/0x10c0 fs/btrfs/file.c:1705
         new_sync_write fs/read_write.c:497 [inline]
         vfs_write+0x6b6/0x1140 fs/read_write.c:590
         ksys_write+0x12f/0x260 fs/read_write.c:643
         do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
         __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
         do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
         entry_SYSENTER_compat_after_hwframe+0x84/0x8e

  -> #2 (btrfs_trans_num_extwriters){++++}-{0:0}:
         join_transaction+0x164/0xf40 fs/btrfs/transaction.c:315
         start_transaction+0x427/0x1a70 fs/btrfs/transaction.c:700
         btrfs_commit_super+0xa1/0x110 fs/btrfs/disk-io.c:4170
         close_ctree+0xcb0/0xf90 fs/btrfs/disk-io.c:4324
         generic_shutdown_super+0x159/0x3d0 fs/super.c:642
         kill_anon_super+0x3a/0x60 fs/super.c:1226
         btrfs_kill_super+0x3b/0x50 fs/btrfs/super.c:2096
         deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
         deactivate_super+0xde/0x100 fs/super.c:506
         cleanup_mnt+0x222/0x450 fs/namespace.c:1267
         task_work_run+0x14e/0x250 kernel/task_work.c:180
         resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
         exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
         exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
         __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
         syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
         __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
         do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
         entry_SYSENTER_compat_after_hwframe+0x84/0x8e

  -> #1 (btrfs_trans_num_writers){++++}-{0:0}:
         __lock_release kernel/locking/lockdep.c:5468 [inline]
         lock_release+0x33e/0x6c0 kernel/locking/lockdep.c:5774
         percpu_up_read include/linux/percpu-rwsem.h:99 [inline]
         __sb_end_write include/linux/fs.h:1650 [inline]
         sb_end_intwrite include/linux/fs.h:1767 [inline]
         __btrfs_end_transaction+0x5ca/0x920 fs/btrfs/transaction.c:1071
         btrfs_commit_inode_delayed_inode+0x228/0x330 fs/btrfs/delayed-inode.c:1301
         btrfs_evict_inode+0x960/0xe80 fs/btrfs/inode.c:5291
         evict+0x2ed/0x6c0 fs/inode.c:667
         iput_final fs/inode.c:1741 [inline]
         iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
         iput+0x5c/0x80 fs/inode.c:1757
         dentry_unlink_inode+0x295/0x480 fs/dcache.c:400
         __dentry_kill+0x1d0/0x600 fs/dcache.c:603
         dput.part.0+0x4b1/0x9b0 fs/dcache.c:845
         dput+0x1f/0x30 fs/dcache.c:835
         ovl_stack_put+0x60/0x90 fs/overlayfs/util.c:132
         ovl_destroy_inode+0xc6/0x190 fs/overlayfs/super.c:182
         destroy_inode+0xc4/0x1b0 fs/inode.c:311
         iput_final fs/inode.c:1741 [inline]
         iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
         iput+0x5c/0x80 fs/inode.c:1757
         dentry_unlink_inode+0x295/0x480 fs/dcache.c:400
         __dentry_kill+0x1d0/0x600 fs/dcache.c:603
         shrink_kill fs/dcache.c:1048 [inline]
         shrink_dentry_list+0x140/0x5d0 fs/dcache.c:1075
         prune_dcache_sb+0xeb/0x150 fs/dcache.c:1156
         super_cache_scan+0x32a/0x550 fs/super.c:221
         do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
         shrink_slab_memcg mm/shrinker.c:548 [inline]
         shrink_slab+0xa87/0x1310 mm/shrinker.c:626
         shrink_one+0x493/0x7c0 mm/vmscan.c:4790
         shrink_many mm/vmscan.c:4851 [inline]
         lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4951
         shrink_node mm/vmscan.c:5910 [inline]
         kswapd_shrink_node mm/vmscan.c:6720 [inline]
         balance_pgdat+0x1105/0x1970 mm/vmscan.c:6911
         kswapd+0x5ea/0xbf0 mm/vmscan.c:7180
         kthread+0x2c1/0x3a0 kernel/kthread.c:389
         ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
         ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

  -> #0 (fs_reclaim){+.+.}-{0:0}:
         check_prev_add kernel/locking/lockdep.c:3134 [inline]
         check_prevs_add kernel/locking/lockdep.c:3253 [inline]
         validate_chain kernel/locking/lockdep.c:3869 [inline]
         __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
         lock_acquire kernel/locking/lockdep.c:5754 [inline]
         lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
         __fs_reclaim_acquire mm/page_alloc.c:3801 [inline]
         fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3815
         might_alloc include/linux/sched/mm.h:334 [inline]
         slab_pre_alloc_hook mm/slub.c:3891 [inline]
         slab_alloc_node mm/slub.c:3981 [inline]
         kmem_cache_alloc_lru_noprof+0x58/0x2f0 mm/slub.c:4020
         btrfs_alloc_inode+0x118/0xb20 fs/btrfs/inode.c:8411
         alloc_inode+0x5d/0x230 fs/inode.c:261
         iget5_locked fs/inode.c:1235 [inline]
         iget5_locked+0x1c9/0x2c0 fs/inode.c:1228
         btrfs_iget_locked fs/btrfs/inode.c:5590 [inline]
         btrfs_iget_path fs/btrfs/inode.c:5607 [inline]
         btrfs_iget+0xfb/0x230 fs/btrfs/inode.c:5636
         add_conflicting_inode fs/btrfs/tree-log.c:5657 [inline]
         copy_inode_items_to_log+0x1039/0x1e30 fs/btrfs/tree-log.c:5928
         btrfs_log_inode+0xa48/0x4660 fs/btrfs/tree-log.c:6592
         log_new_delayed_dentries fs/btrfs/tree-log.c:6363 [inline]
         btrfs_log_inode+0x27dd/0x4660 fs/btrfs/tree-log.c:6718
         btrfs_log_all_parents fs/btrfs/tree-log.c:6833 [inline]
         btrfs_log_inode_parent+0x22ba/0x2a90 fs/btrfs/tree-log.c:7141
         btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7180
         btrfs_sync_file+0x9c1/0xe10 fs/btrfs/file.c:1959
         vfs_fsync_range+0x141/0x230 fs/sync.c:188
         generic_write_sync include/linux/fs.h:2794 [inline]
         btrfs_do_write_iter+0x584/0x10c0 fs/btrfs/file.c:1705
         do_iter_readv_writev+0x504/0x780 fs/read_write.c:741
         vfs_writev+0x36f/0xde0 fs/read_write.c:971
         do_pwritev+0x1b2/0x260 fs/read_write.c:1072
         __do_compat_sys_pwritev2 fs/read_write.c:1218 [inline]
         __se_compat_sys_pwritev2 fs/read_write.c:1210 [inline]
         __ia32_compat_sys_pwritev2+0x121/0x1b0 fs/read_write.c:1210
         do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
         __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
         do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
         entry_SYSENTER_compat_after_hwframe+0x84/0x8e

  other info that might help us debug this:

  Chain exists of:
    fs_reclaim --> btrfs_trans_num_extwriters --> &ei->log_mutex

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&ei->log_mutex);
                                 lock(btrfs_trans_num_extwriters);
                                 lock(&ei->log_mutex);
    lock(fs_reclaim);

   *** DEADLOCK ***

  7 locks held by syz-executor.1/9919:
   #0: ffff88802be20420 (sb_writers#23){.+.+}-{0:0}, at: do_pwritev+0x1b2/0x260 fs/read_write.c:1072
   #1: ffff888065c0f8f0 (&sb->s_type->i_mutex_key#33){++++}-{3:3}, at: inode_lock include/linux/fs.h:791 [inline]
   #1: ffff888065c0f8f0 (&sb->s_type->i_mutex_key#33){++++}-{3:3}, at: btrfs_inode_lock+0xc8/0x110 fs/btrfs/inode.c:385
   #2: ffff888065c0f778 (&ei->i_mmap_lock){++++}-{3:3}, at: btrfs_inode_lock+0xee/0x110 fs/btrfs/inode.c:388
   #3: ffff88802be20610 (sb_internal#4){.+.+}-{0:0}, at: btrfs_sync_file+0x95b/0xe10 fs/btrfs/file.c:1952
   #4: ffff8880546323f0 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x430/0xf40 fs/btrfs/transaction.c:290
   #5: ffff888054632418 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x430/0xf40 fs/btrfs/transaction.c:290
   #6: ffff88804b569358 (&ei->log_mutex){+.+.}-{3:3}, at: btrfs_log_inode+0x39c/0x4660 fs/btrfs/tree-log.c:6481

  stack backtrace:
  CPU: 2 PID: 9919 Comm: syz-executor.1 Not tainted 6.10.0-rc2-syzkaller-00361-g061d1af7b030 #0
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:88 [inline]
   dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
   check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
   check_prev_add kernel/locking/lockdep.c:3134 [inline]
   check_prevs_add kernel/locking/lockdep.c:3253 [inline]
   validate_chain kernel/locking/lockdep.c:3869 [inline]
   __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
   lock_acquire kernel/locking/lockdep.c:5754 [inline]
   lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
   __fs_reclaim_acquire mm/page_alloc.c:3801 [inline]
   fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3815
   might_alloc include/linux/sched/mm.h:334 [inline]
   slab_pre_alloc_hook mm/slub.c:3891 [inline]
   slab_alloc_node mm/slub.c:3981 [inline]
   kmem_cache_alloc_lru_noprof+0x58/0x2f0 mm/slub.c:4020
   btrfs_alloc_inode+0x118/0xb20 fs/btrfs/inode.c:8411
   alloc_inode+0x5d/0x230 fs/inode.c:261
   iget5_locked fs/inode.c:1235 [inline]
   iget5_locked+0x1c9/0x2c0 fs/inode.c:1228
   btrfs_iget_locked fs/btrfs/inode.c:5590 [inline]
   btrfs_iget_path fs/btrfs/inode.c:5607 [inline]
   btrfs_iget+0xfb/0x230 fs/btrfs/inode.c:5636
   add_conflicting_inode fs/btrfs/tree-log.c:5657 [inline]
   copy_inode_items_to_log+0x1039/0x1e30 fs/btrfs/tree-log.c:5928
   btrfs_log_inode+0xa48/0x4660 fs/btrfs/tree-log.c:6592
   log_new_delayed_dentries fs/btrfs/tree-log.c:6363 [inline]
   btrfs_log_inode+0x27dd/0x4660 fs/btrfs/tree-log.c:6718
   btrfs_log_all_parents fs/btrfs/tree-log.c:6833 [inline]
   btrfs_log_inode_parent+0x22ba/0x2a90 fs/btrfs/tree-log.c:7141
   btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7180
   btrfs_sync_file+0x9c1/0xe10 fs/btrfs/file.c:1959
   vfs_fsync_range+0x141/0x230 fs/sync.c:188
   generic_write_sync include/linux/fs.h:2794 [inline]
   btrfs_do_write_iter+0x584/0x10c0 fs/btrfs/file.c:1705
   do_iter_readv_writev+0x504/0x780 fs/read_write.c:741
   vfs_writev+0x36f/0xde0 fs/read_write.c:971
   do_pwritev+0x1b2/0x260 fs/read_write.c:1072
   __do_compat_sys_pwritev2 fs/read_write.c:1218 [inline]
   __se_compat_sys_pwritev2 fs/read_write.c:1210 [inline]
   __ia32_compat_sys_pwritev2+0x121/0x1b0 fs/read_write.c:1210
   do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
   __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
   do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
   entry_SYSENTER_compat_after_hwframe+0x84/0x8e
  RIP: 0023:0xf7334579
  Code: b8 01 10 06 03 (...)
  RSP: 002b:00000000f5f265ac EFLAGS: 00000292 ORIG_RAX: 000000000000017b
  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000200002c0
  RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000
  RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Fix this by ensuring we are under a NOFS scope whenever we call
btrfs_iget() during inode logging and log replay.

Reported-by: syzbot+8576cfa84070dce4d59b@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000274a3a061abbd928@google.com/
Fixes: 712e36c5f2 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2024-06-25 00:33:47 +02:00
Linus Torvalds
50736169ec for-6.10-rc4-tag
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Merge tag 'for-6.10-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix potential infinite loop when doing block grou reclaim

 - fix crash on emulated zoned device and NOCOW files

* tag 'for-6.10-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: zoned: allocate dummy checksums for zoned NODATASUM writes
  btrfs: retry block group reclaim without infinite loop
2024-06-20 11:25:51 -07:00
Johannes Thumshirn
cebae292e0 btrfs: zoned: allocate dummy checksums for zoned NODATASUM writes
Shin'ichiro reported that when he's running fstests' test-case
btrfs/167 on emulated zoned devices, he's seeing the following NULL
pointer dereference in 'btrfs_zone_finish_endio()':

  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] PREEMPT SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
  CPU: 4 PID: 2332440 Comm: kworker/u80:15 Tainted: G        W          6.10.0-rc2-kts+ #4
  Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020
  Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
  RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]

  RSP: 0018:ffff88867f107a90 EFLAGS: 00010206
  RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff893e5534
  RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088
  RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed1081696028
  R10: ffff88840b4b0143 R11: ffff88834dfff600 R12: ffff88840b4b0000
  R13: 0000000000020000 R14: 0000000000000000 R15: ffff888530ad5210
  FS:  0000000000000000(0000) GS:ffff888e3f800000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f87223fff38 CR3: 00000007a7c6a002 CR4: 00000000007706f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  PKRU: 55555554
  Call Trace:
   <TASK>
   ? __die_body.cold+0x19/0x27
   ? die_addr+0x46/0x70
   ? exc_general_protection+0x14f/0x250
   ? asm_exc_general_protection+0x26/0x30
   ? do_raw_read_unlock+0x44/0x70
   ? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]
   btrfs_finish_one_ordered+0x5d9/0x19a0 [btrfs]
   ? __pfx_lock_release+0x10/0x10
   ? do_raw_write_lock+0x90/0x260
   ? __pfx_do_raw_write_lock+0x10/0x10
   ? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs]
   ? _raw_write_unlock+0x23/0x40
   ? btrfs_finish_ordered_zoned+0x5a9/0x850 [btrfs]
   ? lock_acquire+0x435/0x500
   btrfs_work_helper+0x1b1/0xa70 [btrfs]
   ? __schedule+0x10a8/0x60b0
   ? __pfx___might_resched+0x10/0x10
   process_one_work+0x862/0x1410
   ? __pfx_lock_acquire+0x10/0x10
   ? __pfx_process_one_work+0x10/0x10
   ? assign_work+0x16c/0x240
   worker_thread+0x5e6/0x1010
   ? __pfx_worker_thread+0x10/0x10
   kthread+0x2c3/0x3a0
   ? trace_irq_enable.constprop.0+0xce/0x110
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x31/0x70
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

Enabling CONFIG_BTRFS_ASSERT revealed the following assertion to
trigger:

  assertion failed: !list_empty(&ordered->list), in fs/btrfs/zoned.c:1815

This indicates, that we're missing the checksums list on the
ordered_extent. As btrfs/167 is doing a NOCOW write this is to be
expected.

Further analysis with drgn confirmed the assumption:

  >>> inode = prog.crashed_thread().stack_trace()[11]['ordered'].inode
  >>> btrfs_inode = drgn.container_of(inode, "struct btrfs_inode", \
         				"vfs_inode")
  >>> print(btrfs_inode.flags)
  (u32)1

As zoned emulation mode simulates conventional zones on regular devices,
we cannot use zone-append for writing. But we're only attaching dummy
checksums if we're doing a zone-append write.

So for NOCOW zoned data writes on conventional zones, also attach a
dummy checksum.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: cbfce4c7fb ("btrfs: optimize the logical to physical mapping for zoned writes")
CC: Naohiro Aota <Naohiro.Aota@wdc.com> # 6.6+
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-06-13 20:43:55 +02:00