ocfs2: move ip_last_trans to struct ocfs2_caching_info

We have the read side of metadata caching isolated to struct
ocfs2_caching_info, now we need the write side.  This means the journal
functions.  The journal only does a couple of things with struct inode.

This change moves the ip_last_trans field onto struct
ocfs2_caching_info as ci_last_trans.  This field tells the journal
whether a pending journal flush is required.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 6e54a49..c9bd7ce 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -77,6 +77,10 @@
 	 */
 	const struct ocfs2_caching_operations *ci_ops;
 
+	/* last transaction we were a part of. */
+	unsigned long		ci_last_trans;
+
+	/* Cache structures */
 	unsigned int		ci_flags;
 	unsigned int		ci_num_cached;
 	union {