linux-kernel - Re: [RFC PATCH] f2fs: preserve direct write semantics when buffering is forced

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]

Message-ID: <ZBzkzg+lr+TOXZcW@google.com>
Date:   Thu, 23 Mar 2023 16:46:22 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Damien Le Moal <Damien.LeMoal@....com>
Cc:     "hch@...radead.org" <hch@...radead.org>,
        Aravind Ramesh <Aravind.Ramesh@....com>,
        "linux-f2fs-devel@...ts.sourceforge.net" 
        <linux-f2fs-devel@...ts.sourceforge.net>,
        "hans@...tronix.com" <hans@...tronix.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Hans Holmberg <Hans.Holmberg@....com>,
        "chao@...nel.org" <chao@...nel.org>
Subject: Re: [RFC PATCH] f2fs: preserve direct write semantics when buffering
 is forced

On 03/23, Damien Le Moal wrote:
> On Thu, 2023-03-23 at 15:14 -0700, Jaegeuk Kim wrote:
> > On 03/20, Christoph Hellwig wrote:
> > > On Mon, Feb 20, 2023 at 01:20:04PM +0100, Hans Holmberg wrote:
> > > > A) Supporting proper direct writes for zoned block devices would
> > > > be the best, but it is currently not supported (probably for
> > > > a good but non-obvious reason). Would it be feasible to
> > > > implement proper direct IO?
> > > 
> > > I don't think why not.  In many ways direct writes to zoned devices
> > > should be easier than non-direct writes.
> > > 
> > > Any comments from the maintainers why the direct I/O writes to
> > > zoned
> > > devices are disabled?  I could not find anything helpful in the
> > > comments
> > > or commit logs.
> > 
> > The direct IO wants to overwrite the data on the same block address,
> > while
> > zoned device does not support it?
> 
> Surely that is not the case with LFS mode, doesn't it ? Otherwise, even
> buffered overwrites would have an issue.

Zoned device only supports LFS mode.

>