From: Jan Kara Subject: Re: [PATCH 3/4] jbd: abort when failed to log metadata buffers (rebased) Date: Mon, 19 May 2008 05:14:31 +0200 Message-ID: <20080519031431.GC10233@duck.suse.cz> References: <482A6E00.6080303@hitachi.com> <482A6F6F.20002@hitachi.com> <20080514131505.GE24363@duck.suse.cz> <482D6171.1090209@hitachi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , sct@redhat.com, adilger@clusterfs.com, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, Josef Bacik , Mingming Cao , Satoshi OSHIMA , sugita To: Hidehiro Kawai Return-path: Received: from styx.suse.cz ([82.119.242.94]:41101 "EHLO mail.suse.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750968AbYESDOd (ORCPT ); Sun, 18 May 2008 23:14:33 -0400 Content-Disposition: inline In-Reply-To: <482D6171.1090209@hitachi.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hello, On Fri 16-05-08 19:26:57, Hidehiro Kawai wrote: > Jan Kara wrote: > > > On Wed 14-05-08 13:49:51, Hidehiro Kawai wrote: > > > >>Subject: [PATCH 3/4] jbd: abort when failed to log metadata buffers > >> > >>If we failed to write metadata buffers to the journal space and > >>succeeded to write the commit record, stale data can be written > >>back to the filesystem as metadata in the recovery phase. > >> > >>To avoid this, when we failed to write out metadata buffers, > >>abort the journal before writing the commit record. > >> > >>Signed-off-by: Hidehiro Kawai > >>--- > >> fs/jbd/commit.c | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >>Index: linux-2.6.26-rc2/fs/jbd/commit.c > >>=================================================================== > >>--- linux-2.6.26-rc2.orig/fs/jbd/commit.c > >>+++ linux-2.6.26-rc2/fs/jbd/commit.c > >>@@ -703,6 +703,9 @@ wait_for_iobuf: > >> __brelse(bh); > >> } > >> > >>+ if (err) > >>+ journal_abort(journal, err); > >>+ > >> J_ASSERT (commit_transaction->t_shadow_list == NULL); > > > > Shouldn't this rather be further just before > > journal_write_commit_record()? We should abort also if writing revoke > > records etc. failed, shouldn't we? > > Unlike metadata blocks, each revoke block has a descriptor with the > sequence number of the commiting transaction. If we failed to write > a revoke block, there should be an old control block, metadata block, > or zero-filled block where we tried to write the revoke block. > In the recovery process, this old invalid block is detected by > checking its magic number and sequence number, then the transaction > is ignored even if we have succeeded to write the commit record. > So I think we don't need to check for errors just after writing > revoke records. Yes, I agree that not doing such check will not cause data corruption but still I think that in case we fail to properly commit a transaction, we should detect the error and abort the journal... Honza -- Jan Kara SUSE Labs, CR