From: Kevin Wolf <kwolf@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: supriyak@linux.vnet.ibm.com, Jeff Cody <jcody@redhat.com>,
eblake@redhat.com, qemu-devel@nongnu.org, stefanha@gmail.com
Subject: Re: [Qemu-devel] [PATCH v2 06/16] block: do not parse BDRV_O_CACHE_WB in raw block drivers
Date: Fri, 14 Sep 2012 09:55:14 +0200 [thread overview]
Message-ID: <5052E2E2.5040307@redhat.com> (raw)
In-Reply-To: <5052E1B2.2080304@redhat.com>
Am 14.09.2012 09:50, schrieb Paolo Bonzini:
> Il 14/09/2012 09:27, Kevin Wolf ha scritto:
>> I can't see how bs->file is needed here for writethrough semantics.
>> bdrv_open_common() sets bs->enable_write_cache to false and
>> bdrv_co_do_writev() checks it and flushes if necessary. Looks fine to me.
>
> You're right.
>
>> In fact, bdrv_open_common() even removes BDRV_O_CACHE_WB, so what Jeff
>> removes here is really dead code (checked with strace: The file isn't
>> opened with O_SYNC even when using -drive format=file).
>
> Yes, it's dead, on the other hand we still honor BDRV_O_CACHE_WB in all
> the other protocols. Either we go and touch all the protocols
> (effectively removing BDRV_O_CACHE_WB from the BlockDriver
> specification), or treating raw-{posix,win32} specially means we leave
> bugs everywhere else.
Yes, touch all protocols and fix them. BDRV_O_CACHE_WB should be for
block.c only.
Kevin
next prev parent reply other threads:[~2012-09-14 7:55 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-13 15:49 [Qemu-devel] [PATCH v2 00/16] block: bdrv_reopen() patches Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 01/16] block: correctly set the keep_read_only flag Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 02/16] block: make bdrv_set_enable_write_cache() modify open_flags Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 03/16] block: Framework for reopening files safely Jeff Cody
2012-09-13 16:20 ` Paolo Bonzini
2012-09-13 20:35 ` Paolo Bonzini
2012-09-13 20:51 ` Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 04/16] block: move aio initialization into a helper function Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 05/16] block: move open flag parsing in raw block drivers to helper functions Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 06/16] block: do not parse BDRV_O_CACHE_WB in raw block drivers Jeff Cody
2012-09-13 16:12 ` Paolo Bonzini
2012-09-13 17:17 ` Jeff Cody
2012-09-13 18:56 ` Paolo Bonzini
2012-09-13 19:04 ` Jeff Cody
2012-09-13 19:44 ` Paolo Bonzini
2012-09-13 20:29 ` Paolo Bonzini
2012-09-13 21:45 ` Jeff Cody
2012-09-14 6:51 ` Paolo Bonzini
2012-09-14 7:54 ` Kevin Wolf
2012-09-14 7:27 ` Kevin Wolf
2012-09-14 7:50 ` Paolo Bonzini
2012-09-14 7:55 ` Kevin Wolf [this message]
2012-09-14 7:55 ` Paolo Bonzini
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 07/16] block: move allocating aligned_buf into a helper function in raw_posix.c Jeff Cody
2012-09-13 17:29 ` Eric Blake
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 08/16] block: raw-posix image file reopen Jeff Cody
2012-09-13 16:02 ` Paolo Bonzini
2012-09-13 16:57 ` Jeff Cody
2012-09-14 7:32 ` Kevin Wolf
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 09/16] block: raw " Jeff Cody
2012-09-13 16:05 ` Paolo Bonzini
2012-09-13 17:02 ` Jeff Cody
2012-09-13 18:53 ` Paolo Bonzini
2012-09-13 19:17 ` Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 10/16] block: qed " Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 11/16] block: qcow2 " Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 12/16] block: qcow " Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 13/16] block: vmdk " Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 14/16] block: raw-win32 driver reopen support Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 15/16] block: convert bdrv_commit() to use bdrv_reopen() Jeff Cody
2012-09-13 15:49 ` [Qemu-devel] [PATCH v2 16/16] block: remove keep_read_only flag from BlockDriverState struct Jeff Cody
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