gfs2: Don't loop forever in gfs2_freeze if withdrawn

Before this patch, function gfs2_freeze would loop forever if the
filesystem it tries to freeze is withdrawn. That's because function
gfs2_lock_fs_check_clean tries to enqueue the glock of the journal and
the gfs2_glock returns -EIO because you can't enqueue a journaled glock
after a withdraw.

Move the check for file system withdraw inside the loop so that the loop
can end when withdraw occurs.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/super.c

@@ -761,12 +761,12 @@ static int gfs2_freeze(struct super_block *sb)
 	if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN)
 		goto out;
 
-	if (gfs2_withdrawn(sdp)) {
-		error = -EINVAL;
-		goto out;
-	}
-
 	for (;;) {
+		if (gfs2_withdrawn(sdp)) {
+			error = -EINVAL;
+			goto out;
+		}
+
 		error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
 		if (!error)
 			break;