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_address.c b/fs/gfs2/ops_address.c
index 15f710f..574b222 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -210,25 +210,23 @@
 {
 	struct inode *inode = page->mapping->host;
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
-	int error;
+	int ret;
 	int done_trans = 0;
 
-	error = gfs2_writepage_common(page, wbc);
-	if (error <= 0)
-		return error;
-
 	if (PageChecked(page)) {
 		if (wbc->sync_mode != WB_SYNC_ALL)
 			goto out_ignore;
-		error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
-		if (error)
+		ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
+		if (ret)
 			goto out_ignore;
 		done_trans = 1;
 	}
-	error = __gfs2_jdata_writepage(page, wbc);
+	ret = gfs2_writepage_common(page, wbc);
+	if (ret > 0)
+		ret = __gfs2_jdata_writepage(page, wbc);
 	if (done_trans)
 		gfs2_trans_end(sdp);
-	return error;
+	return ret;
 
 out_ignore:
 	redirty_page_for_writepage(wbc, page);