linux-kernel - Re: [PATCH v3 5/5] ext4: Defer mmap cmtime update until writeback

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:	Tue, 20 Aug 2013 12:38:49 +1000
From:	Dave Chinner <david@...morbit.com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org,
	Theodore Ts'o <tytso@....edu>,
	Dave Hansen <dave.hansen@...ux.intel.com>, xfs@....sgi.com,
	Jan Kara <jack@...e.cz>, Tim Chen <tim.c.chen@...ux.intel.com>,
	Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH v3 5/5] ext4: Defer mmap cmtime update until writeback

On Fri, Aug 16, 2013 at 04:22:12PM -0700, Andy Lutomirski wrote:
> A fancier implementation could probably avoid an extra journal
> transaction by adding a mapping_test_clear_cmtime call in
> ext4_writepages, but this should already be a considerable
> improvement -- we'll start one transaction per writepages call
> instead of one per page.

I'd like to see more than just an ext4 implementation - btrfs and
XFS are the other main filesystems that should behave identically.

Also, it's worthwhile to write a generic xfstest to ensure that they
all update the timestamp appropriately - if its' in xfstests, then
we can basically guarantee that it won't get randomly regressed in
future, and other filesystems can be easily verified as well sa
their implement this.

Cheers,

Dave.
-- 
Dave Chinner
david@...morbit.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/