Re: [PATCH RFC v2] xfs: Print XFS UUID on mount and umount events.

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, May 19, 2021 at 05:22:48PM +0200, Lukas Herbolt wrote:
> As of now only device names are printed out over __xfs_printk().
> The device names are not persistent across reboots which in case
> of searching for origin of corruption brings another task to properly
> identify the devices. This patch add XFS UUID upon every mount/umount
> event which will make the identification much easier.

A few questions....

Are you going to wire up fs uuid logging for the other filesystems that
support them?

What happens w.r.t. uuid disambiguation if someone uses a nouuid mount
to mount a filesystem with the same uuid as an already-mounted xfs?

The changes themselves look ok, but I'm wondering what the use case is
here.

--D

> 
> Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
> ---
> V2: Drop void casts and fix long lines
> 
>  fs/xfs/xfs_log.c   | 10 ++++++----
>  fs/xfs/xfs_super.c |  2 +-
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index 06041834daa31..8f4f671fd80d5 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -570,12 +570,14 @@ xfs_log_mount(
>  	int		min_logfsbs;
>  
>  	if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
> -		xfs_notice(mp, "Mounting V%d Filesystem",
> -			   XFS_SB_VERSION_NUM(&mp->m_sb));
> +		xfs_notice(mp, "Mounting V%d Filesystem %pU",
> +			   XFS_SB_VERSION_NUM(&mp->m_sb),
> +			   &mp->m_sb.sb_uuid);
>  	} else {
>  		xfs_notice(mp,
> -"Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.",
> -			   XFS_SB_VERSION_NUM(&mp->m_sb));
> +"Mounting V%d filesystem %pU in no-recovery mode. Filesystem will be inconsistent.",
> +			   XFS_SB_VERSION_NUM(&mp->m_sb),
> +			   &mp->m_sb.sb_uuid);
>  		ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
>  	}
>  
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index e5e0713bebcd8..a4b8a5ad8039f 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1043,7 +1043,7 @@ xfs_fs_put_super(
>  	if (!sb->s_fs_info)
>  		return;
>  
> -	xfs_notice(mp, "Unmounting Filesystem");
> +	xfs_notice(mp, "Unmounting Filesystem %pU", &mp->m_sb.sb_uuid);
>  	xfs_filestream_unmount(mp);
>  	xfs_unmountfs(mp);
>  
> -- 
> 2.31.1
>