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From: Christoph Hellwig <hch@lst.de>
To: ronnie sahlberg <ronniesahlberg@gmail.com>
Cc: kwolf@redhat.com, Christoph Hellwig <hch@lst.de>,
	stefanha@linux.vnet.ibm.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] iSCSI support for QEMU, update
Date: Fri, 22 Apr 2011 08:38:48 +0200	[thread overview]
Message-ID: <20110422063848.GA11449@lst.de> (raw)
In-Reply-To: <BANLkTinw0EmXFU8SNkDsvX=G_ohF1tWWTg@mail.gmail.com>

On Fri, Apr 22, 2011 at 04:35:11PM +1000, ronnie sahlberg wrote:
> Ok, I am confused

And this time it's my fault, sorry.

> I have to set FUA if the WB(I guessed this meant write-back) flag is set?
> Not the opposite (I assume opposite of write-back is write-through) ?

Sorry, I meant exactly the opposite.  You do not have to set FUA if either
of those two flags is present, so:

	if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE))
		caching is ok, write with FUA=0
	else
		caching is NOT ok, write with FUA=1

  reply	other threads:[~2011-04-22  6:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-21 20:23 [Qemu-devel] iSCSI support for QEMU, update ronniesahlberg
2011-04-22  4:08 ` Christoph Hellwig
2011-04-22  6:08   ` ronnie sahlberg
2011-04-22  6:13     ` Christoph Hellwig
2011-04-22  6:35       ` ronnie sahlberg
2011-04-22  6:38         ` Christoph Hellwig [this message]
  -- strict thread matches above, loose matches on Subject: below --
2011-05-07  6:17 Ronnie Sahlberg

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