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Date: Sun, 01 Jul 2012 16:50:29 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC PATCH 3/3] block: gluster as block backend
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Vijay Bellur <vbellur@redhat.com>, Amar Tumballi <amarts@redhat.com>, qemu-devel@nongnu.org, bharata@linux.vnet.ibm.com

Il 19/06/2012 13:05, Stefan Hajnoczi ha scritto:
>> > I picked up this logic from block/raw-posix.c:raw_open_common(). Don't see
>> > anything related to bs->enable_write_cache there. Will find out more about
>> > bs->enable_write_cache.
> If you fetch the latest qemu.git and check bdrv_open_common() there is
> new code that stashes BDRV_O_CACHE_WB in bs->enable_write_cache and
> then opens the actual block driver with BDRV_O_CACHE_WB set.  You can
> use bdrv_enable_write_cache() to test the original flag.

Yes, but you shouldn't do this when opening.  You should always open for
writeback.

Paolo