Re: [PATCH] btrfs: fix replace/scrub failure with metadata_uuid

[David Sterba <dsterba@suse.cz>]

On Fri, Jul 28, 2023 at 02:48:13PM +0800, Anand Jain wrote:
> Fstests with POST_MKFS_CMD="btrfstune -m" (as in the mailing list)
> reported a few of the test cases failing.
> 
> The failure scenario can be summaried and simplified as follows:
> 
>   $ mkfs.btrfs -fq -draid1 -mraid1 /dev/sdb1 /dev/sdb2 :0
>   $ btrfstune -m /dev/sdb1 :0
>   $ wipefs -a /dev/sdb1 :0
>   $ mount -o degraded /dev/sdb2 /btrfs :0
>   $ btrfs replace start -B -f -r 1 /dev/sdb1 /btrfs :1
>     STDERR:
>     ERROR: ioctl(DEV_REPLACE_START) failed on "/btrfs": Input/output error
> 
>   [11290.583502] BTRFS warning (device sdb2): tree block 22036480 mirror 2 has bad fsid, has 99835c32-49f0-4668-9e66-dc277a96b4a6 want da40350c-33ac-4872-92a8-4948ed8c04d0
>   [11290.586580] BTRFS error (device sdb2): unable to fix up (regular) error at logical 22020096 on dev /dev/sdb8 physical 1048576
> 
> As above, the replace is failing because we are verifying the header with
> fs_devices::fsid instead of fs_devices::metadata_uuid, despite the
> metadata_uuid actually being present.
> 
> To fix this, use fs_devices::metadata_uuid;
> 
> (We copy fsid into fs_devices::metadata_uuid if there is no
> metadata_uuid, so its fine).
> 
> Fixes: a3ddbaebc7c9 ("btrfs: scrub: introduce a helper to verify one metadata block")
> Signed-off-by: Anand Jain <anand.jain@oracle.com>

Added to misc-next, thanks.