[PATCH] ext3/4: fix J_ASSERT(transaction->t_updates > 0) in journal_stop()

A disk generated some I/O error, after it, I hitted
J_ASSERT(transaction->t_updates > 0) in journal_stop().

It seems to happened on ext3_truncate() path from stack trace. Then,
maybe the following case may trigger J_ASSERT(transaction->t_updates > 0).

ext3_truncate()
    -> ext3_free_branches()
        -> ext3_journal_test_restart()
	    -> ext3_journal_restart()
                -> journal_restart()
                transaction->t_updates--;
                /* another process aborted journal */
                    -> start_this_handle()
		    returns -EROFS without transaction->t_updates++;

    -> ext3_journal_stop()
        -> journal_stop()
	J_ASSERT(transaction->t_updates > 0)

If journal was aborted in middle of journal_restart(), ext3_truncate()
may trigger J_ASSERT().

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index e1b3c8af4d17..d5c63047a8b3 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -1314,13 +1314,14 @@ int journal_stop(handle_t *handle)
         int old_handle_count, err;
         pid_t pid;
 
-        J_ASSERT(transaction->t_updates > 0);
         J_ASSERT(journal_current_handle() == handle);
 
         if (is_handle_aborted(handle))
                 err = -EIO;
-        else
+        else {
+                J_ASSERT(transaction->t_updates > 0);
                 err = 0;
+        }
 
         if (--handle->h_ref > 0) {
                 jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,