mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-29 13:53:33 +00:00
Code Issues Releases Wiki Activity

btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range

Browse source 
If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.

Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.

So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.

Reported-by: syzbot+0b1fb6b0108c27419f9f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@google.com/
CC: stable@vger.kernel.org # 5.4+
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>
This commit is contained in:
Filipe Manana 2022-11-28 15:07:30 +00:00 committed by David Sterba
parent 1742e1c90c
commit 162d053e15
1 changed files with 8 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
fs/btrfs/file.c
View file

@ -380,7 +380,10 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
args->start - extent_offset,
0, false);
ret = btrfs_inc_extent_ref(trans, &ref);
BUG_ON(ret); /* -ENOMEM */
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
}
key.offset = args->start;
}
@ -467,7 +470,10 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
key.offset - extent_offset, 0,
false);
ret = btrfs_free_extent(trans, &ref);
BUG_ON(ret); /* -ENOMEM */
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
args->bytes_found += extent_end - key.offset;
}