2024-01-03 10:32:12

by Fedor Pchelkin

Subject: [PATCH] btrfs: ref-verify: free ref cache before clearing mount opt

As clearing REF_VERIFY mount option indicates there were some errors in a
ref-verify process, a ref cache is not relevant anymore and should be
freed.

btrfs_free_ref_cache() requires REF_VERIFY option being set so call
it just before clearing the mount option.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool")
Reported-by: [email protected]
Closes: https://lore.kernel.org/lkml/[email protected]/
Reported-by: [email protected]
Closes: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Fedor Pchelkin <[email protected]>
---
fs/btrfs/ref-verify.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 6486f0d7e993..8c4fc98ca9ce 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -889,8 +889,10 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
out_unlock:
spin_unlock(&fs_info->ref_verify_lock);
out:
- if (ret)
+ if (ret) {
+ btrfs_free_ref_cache(fs_info);
btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
+ }
return ret;
}

@@ -1021,8 +1023,8 @@ int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
}
}
if (ret) {
- btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
btrfs_free_ref_cache(fs_info);
+ btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
}
btrfs_free_path(path);
return ret;
--
2.43.0

2024-01-04 03:43:57

by Anand Jain

Subject: Re: [PATCH] btrfs: ref-verify: free ref cache before clearing mount opt

Reviewed-by: Anand Jain <[email protected]>

Thx, Anand

2024-01-04 16:01:18

by David Sterba

Subject: Re: [PATCH] btrfs: ref-verify: free ref cache before clearing mount opt

On Wed, Jan 03, 2024 at 01:31:27PM +0300, Fedor Pchelkin wrote:
> As clearing REF_VERIFY mount option indicates there were some errors in a
> ref-verify process, a ref cache is not relevant anymore and should be
> freed.
>
> btrfs_free_ref_cache() requires REF_VERIFY option being set so call
> it just before clearing the mount option.
>
> Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
>
> Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool")
> Reported-by: [email protected]
> Closes: https://lore.kernel.org/lkml/[email protected]/
> Reported-by: [email protected]
> Closes: https://lore.kernel.org/lkml/[email protected]/
> Signed-off-by: Fedor Pchelkin <[email protected]>

Added to misc-next, thanks.