linux-ext4 - Re: Enable asynchronous commits by default patch revoked?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 26 Aug 2009 18:02:31 +0200
From:	Jan Kara <jack@...e.cz>
To:	Theodore Tso <tytso@....edu>
Cc:	Andreas Dilger <adilger@....com>,
	Ric Wheeler <rwheeler@...hat.com>,
	Christian Fischer <Christian.Fischer@...terngraphics.com>,
	linux-ext4@...r.kernel.org
Subject: Re: Enable asynchronous commits by default patch revoked?

> On Mon, Aug 24, 2009 at 05:43:36PM -0600, Andreas Dilger wrote:
> > Without transaction checksums waiting on all of the blocks together
> > is NOT safe.  If the commit record is on disk, but the rest of the
> > transaction's blocks are not then during replay it may cause garbage
> > to be written from the journal into the filesystem metadata.
> 
> Yes, I *said* that we can only wait on all of the blocks together with
> the commit record when doing journal checksums.  Sorry if I didn't
> make that clear enough.
  I suppose we talk about the case when write caches are turned off and
we use barrier=0 (because case barrier=1 does not really care about when
we wait for the blocks from the correctness POV - at least according to
Documentation/block/barrier.txt). In that case, you have to wait for
*data* blocks before writing the commit block because you have no
checksumming of those...

									Honza
-- 
Jan Kara <jack@...e.cz>
SuSE CR Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html