xfs: use super s_id instead of struct xfs_mount m_fsname

Eliminate struct xfs_mount field m_fsname by using the super block s_id
field directly.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 3e8eedf..5ea9524 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -667,7 +667,8 @@ xfs_mountfs(
 	/* enable fail_at_unmount as default */
 	mp->m_fail_unmount = true;
 
-	error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
+	error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype,
+			       NULL, mp->m_super->s_id);
 	if (error)
 		goto out;
 
@@ -1241,7 +1242,7 @@ xfs_mod_fdblocks(
 	printk_once(KERN_WARNING
 		"Filesystem \"%s\": reserve blocks depleted! "
 		"Consider increasing reserve pool size.",
-		mp->m_fsname);
+		mp->m_super->s_id);
 fdblocks_enospc:
 	spin_unlock(&mp->m_sb_lock);
 	return -ENOSPC;