[GFS2] don't try to lockfs after shutdown

If an fs has already been shut down, a lockfs callback should do nothing.
An fs that's been shut down can't acquire locks or do anything with
respect to the cluster.

Also, remove FIXME comment in withdraw function.  The missing bits of the
withdraw procedure are now all done by user space.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/lm.c

@@ -104,15 +104,9 @@ int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
 	vprintk(fmt, args);
 	va_end(args);
 
-	fs_err(sdp, "about to withdraw from the cluster\n");
+	fs_err(sdp, "about to withdraw this file system\n");
 	BUG_ON(sdp->sd_args.ar_debug);
 
-
-	fs_err(sdp, "waiting for outstanding I/O\n");
-
-	/* FIXME: suspend dm device so oustanding bio's complete
-	   and all further io requests fail */
-
 	fs_err(sdp, "telling LM to withdraw\n");
 	gfs2_withdraw_lockproto(&sdp->sd_lockstruct);
 	fs_err(sdp, "withdrawn\n");

fs/gfs2/ops_super.c

@@ -173,6 +173,9 @@ static void gfs2_write_super_lockfs(struct super_block *sb)
 	struct gfs2_sbd *sdp = sb->s_fs_info;
 	int error;
 
+	if (test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
+		return;
+
 	for (;;) {
 		error = gfs2_freeze_fs(sdp);
 		if (!error)