linux-kernel - Re: [PATCH 1/3] xen/blk[front|back]: Use the full FLUSH

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: <20110911003306.GB9989@oracle.com>
Date:	Sat, 10 Sep 2011 20:33:06 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com,
	JBeulich@...ell.com, jeremy.fitzhardinge@...rix.com,
	axboe@...nel.dk
Subject: Re: [PATCH 1/3] xen/blk[front|back]: Use the full FLUSH | FUA
 instead of just FLUSH.

On Sat, Sep 10, 2011 at 02:08:49PM -0400, Christoph Hellwig wrote:
> On Fri, Sep 09, 2011 at 02:30:59PM -0400, Konrad Rzeszutek Wilk wrote:
> > During a FLUSH we can pass sector number that we want to
> > have flushed - which is what FUA requests are.
> 
> No, that is not the case.
> 
> REQ_FLUSH without data		-> pure flush
> REQ_FLUSH with data		-> preflush plus write

Excellent. So we have been doing it right all along.

> REQ_FUA				-> write and ranged postflush

Ah, somehow I was thinking that you can't write data with a
REQ_FLUSH, but that is nonsense as the block/blk-flush.c
explains in great details.

Will drop this patch - and thanks for clarifying it!
--
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/