From: Bob Peterson <rpeterso@redhat.com>
Subject: [RHEL 5.1] [GFS2] bz #246114: GFS2: soft lockup in rgblk_search
Date: Thu, 12 Jul 2007 17:03:42 -0500
Bugzilla: 246114
Message-Id: <1184277822.517.18.camel@technetium.msp.redhat.com>
Changelog: [GFS2] soft lockup in rgblk_search


This patch fixes the problem described in bugzilla bug 246114.

The code was looping in the relatively new section of code designed to
search for and reuse unlinked inodes.  In cases where it was finding an
appropriate inode to reuse, it was looping around and finding the same
block over and over because a "<=" check should have been a "<" when
comparing the goal block to the last unlinked block found.

It was tested on the roth cluster using the revolver QE test.

Regards,

Bob Peterson
Red Hat Cluster Suite

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
--
diff -pur a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
--- a/fs/gfs2/rgrp.c	2007-07-10 12:28:02.000000000 -0500
+++ b/fs/gfs2/rgrp.c	2007-07-12 16:02:08.000000000 -0500
@@ -863,16 +863,19 @@ static struct inode *try_rgrp_unlink(str
 	u64 no_addr;
 
 	for(;;) {
+		if (goal >= rgd->rd_data)
+			break;
 		goal = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED,
 				    GFS2_BLKST_UNLINKED);
 		if (goal == 0)
-			return 0;
+			break;
 		no_addr = goal + rgd->rd_data0;
-		if (no_addr <= *last_unlinked)
+		goal++;
+		if (no_addr < *last_unlinked)
 			continue;
 		*last_unlinked = no_addr;
 		inode = gfs2_inode_lookup(rgd->rd_sbd->sd_vfs, DT_UNKNOWN,
-					no_addr, -1);
+					  no_addr, -1);
 		if (!IS_ERR(inode))
 			return inode;
 	}