From: Kevin Wolf <kwolf@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 01/11] block: Use writeback in .bdrv_create() implementations
Date: Wed, 9 Mar 2016 13:27:09 +0100 [thread overview]
Message-ID: <20160309122709.GF5205@noname.redhat.com> (raw)
In-Reply-To: <56E013BA.8010606@redhat.com>
Am 09.03.2016 um 13:14 hat Paolo Bonzini geschrieben:
>
>
> On 08/03/2016 17:34, Kevin Wolf wrote:
> > There's no reason to use a writethrough cache mode while creating an
> > image.
>
> There's no reason to do flushes in fact, so you could use
> BDRV_O_NO_FLUSH too. :)
That's true. On the other hand, we don't issue flushes anyway, so
there's little reason to ignore non-existing flushes. :-)
The only part where it might make sense is where image formats don't
open the raw image file, but actually open the image with themselves and
allocate things. qcow2 at least already sets BDRV_O_NO_FLUSH for that
part.
In fact, the only bdrv_open() touched in this patch that doesn't have
BDRV_O_PROTOCOL set, is one instance in VMDK where it opens the backing
file to read some ID from the header. So no flush involved there.
Kevin
next prev parent reply other threads:[~2016-03-09 12:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 16:34 [Qemu-devel] [PATCH 00/11] block: Use BB function in .bdrv_create() implementations Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 01/11] block: Use writeback " Kevin Wolf
2016-03-09 12:14 ` Paolo Bonzini
2016-03-09 12:27 ` Kevin Wolf [this message]
2016-03-08 16:34 ` [Qemu-devel] [PATCH 02/11] block: Introduce blk_set_allow_write_beyond_eof() Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 03/11] parallels: Use BB functions in .bdrv_create() Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 04/11] qcow: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 05/11] qcow2: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 06/11] qed: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 07/11] sheepdog: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 08/11] vdi: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 09/11] vhdx: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 10/11] vmdk: " Kevin Wolf
2016-03-08 16:34 ` [Qemu-devel] [PATCH 11/11] vpc: " Kevin Wolf
2016-03-14 11:31 ` [Qemu-devel] [PATCH 00/11] block: Use BB function in .bdrv_create() implementations Kevin Wolf
2016-03-14 16:55 ` Max Reitz
2016-03-14 17:34 ` Kevin Wolf
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