Re: [PATCH 6.6] btrfs: tree-checker: add type and sequence check for inline backrefs

[Greg KH <greg@kroah.com>]

On Tue, Jul 16, 2024 at 06:45:49PM +0930, Qu Wenruo wrote:
> commit 1645c283a87c61f84b2bffd81f50724df959b11a upstream.
> 
> [BUG]
> There is a bug report that ntfs2btrfs had a bug that it can lead to
> transaction abort and the filesystem flips to read-only.
> 
> [CAUSE]
> For inline backref items, kernel has a strict requirement for their
> ordered, they must follow the following rules:
> 
> - All btrfs_extent_inline_ref::type should be in an ascending order
> 
> - Within the same type, the items should follow a descending order by
>   their sequence number
> 
>   For EXTENT_DATA_REF type, the sequence number is result from
>   hash_extent_data_ref().
>   For other types, their sequence numbers are
>   btrfs_extent_inline_ref::offset.
> 
> Thus if there is any code not following above rules, the resulted
> inline backrefs can prevent the kernel to locate the needed inline
> backref and lead to transaction abort.
> 
> [FIX]
> Ntrfs2btrfs has already fixed the problem, and btrfs-progs has added the
> ability to detect such problems.
> 
> For kernel, let's be more noisy and be more specific about the order, so
> that the next time kernel hits such problem we would reject it in the
> first place, without leading to transaction abort.
> 
> Cc: stable@vger.kernel.org # 6.6
> Link: https://github.com/kdave/btrfs-progs/pull/622
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> [ Fix a conflict due to header cleanup. ]
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> Signed-off-by: David Sterba <dsterba@suse.com>
> ---
>  fs/btrfs/tree-checker.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)

Now queued up, thanks.

greg k-h