linux-ext4 - Re: [PATCH 0/3] ext2, ext4, xfs: hard fail dax mount on unsupported devices

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20181012082154.GB30154@lst.de>
Date:   Fri, 12 Oct 2018 10:21:54 +0200
From:   Christoph Hellwig <hch@....de>
To:     Eric Sandeen <sandeen@...deen.net>
Cc:     Dan Williams <dan.j.williams@...el.com>, Jan Kara <jack@...e.cz>,
        linux-xfs <linux-xfs@...r.kernel.org>,
        linux-ext4 <linux-ext4@...r.kernel.org>,
        Ross Zwisler <zwisler@...nel.org>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH 0/3] ext2, ext4, xfs: hard fail dax mount on
 unsupported devices

On Thu, Oct 11, 2018 at 01:38:34PM -0500, Eric Sandeen wrote:
> > The different behavior between filesystems was confusing customers so
> > we had to align them, then the question was which default to pick.
> > Honestly, we came to the decision to bring ext4 in line with the xfs
> > behavior because we thought that would be easier than the alternative.
> > Dave and Christoph made repeated arguments that DAX is just a hidden
> > performance optimization that no application should rely on, so we
> > went the path of least resistance and changed the ext4 default.
> 
> Ok, well, I guess we'd better reconcile "it's a hidden performance hint"
> with "if the administrator asked they must receive..." before making this
> change... cc: hch for bonus input.

I don't really care too mouch on the mount options, the important bit
was the application behavior.

I fully agree with Dan that we should have the same behavior for every
file system, though.