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 08:13:47 +0200 [thread overview]
Message-ID: <20110422061347.GA11066@lst.de> (raw)
In-Reply-To: <BANLkTi=UDqtZFG+XqmspLHx1M33VOu6H+g@mail.gmail.com>
On Fri, Apr 22, 2011 at 04:08:57PM +1000, ronnie sahlberg wrote:
> So I should set FUA when
> BDRV_O_CACHE_WB==0 or BDRV_O_NOCACHE==1
> right?
At this point you need to set it if either the BDRV_O_CACHE_WB and
BDRV_O_NOCACHE flags are set. And yes, the naming of the nocache
flag is rather confusing.
Take a look at block.c:bdrv_open_common():
/*
* Yes, BDRV_O_NOCACHE aka O_DIRECT means we have to present a
* write cache to the guest. We do need the fdatasync to flush
* out transactions for block allocations, and we maybe have a
* volatile write cache in our backing device to deal with.
*/
if (flags & (BDRV_O_CACHE_WB|BDRV_O_NOCACHE))
bs->enable_write_cache = 1;
next prev parent reply other threads:[~2011-04-22 6:13 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 [this message]
2011-04-22 6:35 ` ronnie sahlberg
2011-04-22 6:38 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2011-05-07 6:17 Ronnie Sahlberg
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