GFS2: Fix up jdata writepage/delete_inode

There is a bug in writepage and delete_inode which allows jdata files to
invalidate pages from the address space without being in a transaction at
the time. This causes problems in case the pages are in the journal. This
patch fixes that case and prevents the resulting oops.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 9c7678d..2cb744b 100644
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -493,7 +493,7 @@
 	gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &ip->i_iopen_gh);
 	error = gfs2_glock_nq(&ip->i_iopen_gh);
 	if (error)
-		goto out_uninit;
+		goto out_truncate;
 
 	if (S_ISDIR(inode->i_mode) &&
 	    (ip->i_di.di_flags & GFS2_DIF_EXHASH)) {
@@ -518,6 +518,7 @@
 	if (error)
 		goto out_unlock;
 
+out_truncate:
 	error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
 	if (error)
 		goto out_unlock;
@@ -526,8 +527,8 @@
 	gfs2_trans_end(sdp);
 
 out_unlock:
-	gfs2_glock_dq(&ip->i_iopen_gh);
-out_uninit:
+	if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags))
+		gfs2_glock_dq(&ip->i_iopen_gh);
 	gfs2_holder_uninit(&ip->i_iopen_gh);
 	gfs2_glock_dq_uninit(&gh);
 	if (error && error != GLR_TRYFAILED)