[GFS2] Fix double locking problem in rename

The rename inode operation was trying to lock the same
inode twice in the case of renaming with the source
and destination directories the same. We now test for
this and just lock once.

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

fs/gfs2/ops_inode.c

@@ -615,13 +615,19 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 			goto out_gunlock_r;
 	}
 
+	num_gh = 1;
 	gfs2_holder_init(odip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
-	gfs2_holder_init(ndip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 1);
-	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 2);
-	num_gh = 3;
+	if (odip != ndip) {
+		gfs2_holder_init(ndip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+		num_gh++;
+	}
+	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+	num_gh++;
 
-	if (nip)
-		gfs2_holder_init(nip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh++);
+	if (nip) {
+		gfs2_holder_init(nip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+		num_gh++;
+	}
 
 	error = gfs2_glock_nq_m(num_gh, ghs);
 	if (error)