From: Eric Sandeen Subject: Re: [PATCH, RFC] jbd2: Call the commit callback before the transaction could get dropped Date: Mon, 27 Oct 2008 21:41:36 -0500 Message-ID: <49067BE0.8090904@redhat.com> References: <1224612181.19719.20.camel@paris-laptop> <20081027181928.GB23111@mit.edu> <49064027.9010509@redhat.com> <20081027232843.GA9797@mit.edu> <49065805.1080303@redhat.com> <20081028015228.GA8320@mit.edu> <20081028022838.GA8869@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Theodore Tso , Eric Sandeen , Eric Paris , linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org Return-path: Received: from mx2.redhat.com ([66.187.237.31]:35145 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751233AbYJ1CmA (ORCPT ); Mon, 27 Oct 2008 22:42:00 -0400 In-Reply-To: <20081028022838.GA8869@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Tso wrote: > This is what I plan to send to Linus to fix the problem. > > commit 6fecbc3c7d27800e90a5f5fbca2fb2847e2c2854 > Author: Theodore Ts'o > Date: Mon Oct 27 22:11:39 2008 -0400 > > jbd2: Call the commit callback before the transaction could get dropped > > The transaction can potentially get dropped if there are no buffers > that need to be written. Make sure we call the commit callback before > potentially deciding to drop the transaction. Also avoid > dereferencing the commit_transaction pointer in the marker for the > same reason. > > This patch fixes the bug reported by Eric Paris at: > http://bugzilla.kernel.org/show_bug.cgi?id=11838 > > Signed-off-by: "Theodore Ts'o" Acked-by: Eric Sandeen > diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c > index 8b119e1..ebc667b 100644 > --- a/fs/jbd2/commit.c > +++ b/fs/jbd2/commit.c > @@ -974,6 +974,9 @@ restart_loop: > journal->j_committing_transaction = NULL; > spin_unlock(&journal->j_state_lock); > > + if (journal->j_commit_callback) > + journal->j_commit_callback(journal, commit_transaction); > + > if (commit_transaction->t_checkpoint_list == NULL && > commit_transaction->t_checkpoint_io_list == NULL) { > __jbd2_journal_drop_transaction(journal, commit_transaction); > @@ -995,11 +998,8 @@ restart_loop: > } > spin_unlock(&journal->j_list_lock); > > - if (journal->j_commit_callback) > - journal->j_commit_callback(journal, commit_transaction); > - > trace_mark(jbd2_end_commit, "dev %s transaction %d head %d", > - journal->j_devname, commit_transaction->t_tid, > + journal->j_devname, journal->j_commit_sequence, > journal->j_tail_sequence); > jbd_debug(1, "JBD: commit %d complete, head %d\n", > journal->j_commit_sequence, journal->j_tail_sequence);