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

[Christoph Hellwig <hch@infradead.org>]

On Wed, May 19, 2021 at 11:37:52AM +0200, Lukas Herbolt wrote:
> As of now only device names are pritend 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
> indetify the devices. This patch add XFS UUID upon every mount/umount
> event which will make the identification much easier.

This looks sensible, but please avoid the pointless casts and overly
long lines.  i.e. something like this:

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index c19a82adea1edb..2089177168f487 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -572,12 +572,14 @@ 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 f7f70438d98703..fa4589d391a892 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);