Commit 2e84f264 authored Aug 15, 2012 by Jan Kara

jbd: don't write superblock when unmounting an ro filesystem



This sequence:

results in an IO error when unmounting the RO filesystem. The bug was
introduced by:

commit 9754e39c
Author: Jan Kara <jack@suse.cz>
Date:   Sat Apr 7 12:33:03 2012 +0200

    jbd: Split updating of journal superblock and marking journal empty

which lost some of the magic in journal_update_superblock() which
used to test for a journal with no outstanding transactions.

This is a port of a jbd2 fix by Eric Sandeen.

CC: <stable@vger.kernel.org> # 3.4.x
Signed-off-by: Jan Kara <jack@suse.cz>

parent 48d17884

fs/jbd/journal.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1113,6 +1113,11 @@ static void mark_journal_empty(journal_t *journal)

		BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
		spin_lock(&journal->j_state_lock);
		/* Is it already empty? */
		if (sb->s_start == 0) {
		spin_unlock(&journal->j_state_lock);
		return;
		}
		jbd_debug(1, "JBD: Marking journal as empty (seq %d)\n",
		journal->j_tail_sequence);