xfs: show uuid when mount fails due to duplicate uuid

When a system tries to mount a filesystem (FS) using UUID, the xfs
returns -EINVAL and shows a message if a FS with the same UUID has
been already mounted. It is useful to output the duplicate UUID
with it.

Signed-off-by: Mitsuo Hayasaka <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Ben Myers <[email protected]>
Cc: Alex Elder <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Ben Myers <[email protected]>

fs/xfs/xfs_mount.c

@@ -158,7 +158,7 @@ xfs_uuid_mount(
 
  out_duplicate:
 	mutex_unlock(&xfs_uuid_table_mutex);
-	xfs_warn(mp, "Filesystem has duplicate UUID - can't mount");
+	xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
 	return XFS_ERROR(EINVAL);
 }