[GFS2] Fix change nlink deadlock

Bugzilla 215088

Fix deadlock in gfs2_change_nlink() while installing RHEL5 into GFS2
partition. The gfs2_rename() apparently needs block allocation for the
new name (into the directory) where it requires rg locks. At the same
time, while updating the nlink count for the replaced file,
gfs2_change_nlink() tries to return the inode meta-data back to resource
group where it needs rg locks too. Our logic doesn't allow process to
acquire these locks recursively by the same process  (RHEL installer)
that results a BUG call. This only happens within rename code path and
only if the destination file exists before the rename operation.

Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index d122074c45e..6bc443644c3 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -281,16 +281,14 @@ out:
 }
 
 /**
- * gfs2_change_nlink - Change nlink count on inode
+ * gfs2_change_nlink_i - Change nlink count on inode
  * @ip: The GFS2 inode
  * @diff: The change in the nlink count required
  *
  * Returns: errno
  */
-
-int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
+int gfs2_change_nlink_i(struct gfs2_inode *ip, int diff)
 {
-	struct gfs2_sbd *sdp = ip->i_inode.i_sb->s_fs_info;
 	struct buffer_head *dibh;
 	u32 nlink;
 	int error;
@@ -322,6 +320,20 @@ int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
 	brelse(dibh);
 	mark_inode_dirty(&ip->i_inode);
 
+	return error;
+}
+
+int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
+{
+	struct gfs2_sbd *sdp = ip->i_inode.i_sb->s_fs_info;
+	int error;
+
+	/* update the nlink */
+	error = gfs2_change_nlink_i(ip, diff);
+	if (error)
+		return error;
+
+	/* return meta data block back to rg */
 	if (ip->i_inode.i_nlink == 0) {
 		struct gfs2_rgrpd *rgd;
 		struct gfs2_holder ri_gh, rg_gh;