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From: Jeff Moyer <jmoyer@redhat.com>
To: Alex Bligh <alex@alex.org.uk>
Cc: "linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	nbd-general@lists.sourceforge.net, Eric Blake <eblake@redhat.com>
Subject: Re: Block layer - meaning of REQ_FUA on not write requests
Date: Fri, 01 Apr 2016 12:06:09 -0400	[thread overview]
Message-ID: <x49fuv5uxe6.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <FA28BBF6-1D91-4F9B-99DF-5C46F27E2D44@alex.org.uk> (Alex Bligh's message of "Fri, 1 Apr 2016 16:27:35 +0100")

Alex Bligh <alex@alex.org.uk> writes:

> I am trying to clean up the documentation of the NBD protocol. NBD's
> support for Force Unit Access (FUA) was modelled on the linux kernel
> block layer. When I added support a few years ago, I omitted to find
> out exactly what types of request it applies to. Obviously it applies
> to write requests, but how about others (e.g. read)?

Any request with REQ_FUA set will be treated as a flush by the block
layer.  As such, we do not expect reads to have this bit set.

Cheers,
Jeff

      reply	other threads:[~2016-04-01 16:06 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-01 15:27 Alex Bligh
2016-04-01 16:06 ` Jeff Moyer [this message]

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