ocfs2: Re-journal buffers after transaction extend

ocfs2_extend_trans() might call journal_restart() which will commit dirty
buffers and then restart the transaction. This means that any buffers which
still need changes should be passed to journal_access() again. Some paths
during extend weren't doing this right.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 0e1250c..8d81f6c 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -174,6 +174,12 @@
  * transaction. extend_trans will either extend the current handle by
  * nblocks, or commit it and start a new one with nblocks credits.
  *
+ * This might call journal_restart() which will commit dirty buffers
+ * and then restart the transaction. Before calling
+ * ocfs2_extend_trans(), any changed blocks should have been
+ * dirtied. After calling it, all blocks which need to be changed must
+ * go through another set of journal_access/journal_dirty calls.
+ *
  * WARNING: This will not release any semaphores or disk locks taken
  * during the transaction, so make sure they were taken *before*
  * start_trans or we'll have ordering deadlocks.