[Cluster-devel] GFS2: Fix use-after-free bug on umount (try #2)

[Steven Whitehouse <swhiteho@redhat.com>]

There were some issues relating to umount hangs with journaled data
with the original patch. I've reverted that, and this patch fixes
the original issue, but without side effects.

From a95b5b8af40786f6d13e5570e25a6ce8608eb793 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho@redhat.com>
Date: Fri, 19 Dec 2008 15:43:05 +0000
Subject: [PATCH] GFS2: Fix use-after-free bug on umount (try #2)

This should solve the issue with the previous attempt at fixing this.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 4cae60f..f91eebd 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1263,17 +1263,21 @@ static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
 static void gfs2_kill_sb(struct super_block *sb)
 {
 	struct gfs2_sbd *sdp = sb->s_fs_info;
-	if (sdp) {
-		gfs2_meta_syncfs(sdp);
-		dput(sdp->sd_root_dir);
-		dput(sdp->sd_master_dir);
-		sdp->sd_root_dir = NULL;
-		sdp->sd_master_dir = NULL;
+
+	if (sdp == NULL) {
+		kill_block_super(sb);
+		return;
 	}
+
+	gfs2_meta_syncfs(sdp);
+	dput(sdp->sd_root_dir);
+	dput(sdp->sd_master_dir);
+	sdp->sd_root_dir = NULL;
+	sdp->sd_master_dir = NULL;
 	shrink_dcache_sb(sb);
 	kill_block_super(sb);
-	if (sdp)
-		gfs2_delete_debugfs_file(sdp);
+	gfs2_delete_debugfs_file(sdp);
+	kfree(sdp);
 }
 
 struct file_system_type gfs2_fs_type = {
diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 08837a7..777783d 100644
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -182,7 +182,6 @@ static void gfs2_put_super(struct super_block *sb)
 
 	/*  At this point, we're through participating in the lockspace  */
 	gfs2_sys_fs_del(sdp);
-	kfree(sdp);
 }
 
 /**
-- 
1.6.0.3