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From: Paolo Bonzini <pbonzini@redhat.com>
To: Ming Lei <ming.lei@canonical.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	Fam Zheng <famz@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue
Date: Thu, 03 Jul 2014 12:50:34 +0200	[thread overview]
Message-ID: <53B5357A.5030001@redhat.com> (raw)
In-Reply-To: <CACVXFVM1H8unfZSyt4RXFKTnv5mHo4N-1sScFnbm5Yc-qFD=gA@mail.gmail.com>

Il 03/07/2014 12:45, Ming Lei ha scritto:
> I think it may be needed:
>
> - following requests coming inside handle_notify():
>          req0, req1, req2-flush, req3
> - both req0 and req1 queued
> - start to handle req2-flush
> - bdrv_co_flush() calls bdrv_co_flush(bs->file), which finally
> call raw_aio_flush() to send command, but the 1st two requests
> should have been submitted to fs before the flush action

No, bdrv_aio_flush is only guaranteed to flush requests that _completed_ 
before it was sent.

Since we haven't yet told the guest that req0 and req1 are complete, 
there is no need to submit them before req2-flush.

Paolo

  reply	other threads:[~2014-07-03 10:50 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-02 12:18 [Qemu-devel] [PATCH v4 0/3] linux-aio: introduce submit I/O as a batch Ming Lei
2014-07-02 12:18 ` [Qemu-devel] [PATCH v4 1/3] block: block: introduce APIs for submitting IO as Ming Lei
2014-07-02 12:46   ` Eric Blake
2014-07-03  9:40   ` Kevin Wolf
2014-07-02 12:18 ` [Qemu-devel] [PATCH v4 2/3] linux-aio: implement io plug, unplug and flush io queue Ming Lei
2014-07-03  9:40   ` Kevin Wolf
2014-07-03  9:51     ` Ming Lei
2014-07-03 10:04       ` Paolo Bonzini
2014-07-03 10:45         ` Ming Lei
2014-07-03 10:50           ` Paolo Bonzini [this message]
2014-07-03 11:31             ` Ming Lei
2014-07-03 10:22       ` Kevin Wolf
2014-07-03 10:24         ` Ming Lei
2014-07-03 10:30           ` Kevin Wolf
2014-07-03 12:24   ` Stefan Hajnoczi
2014-07-04  9:18     ` Ming Lei
2014-07-04  9:21       ` Ming Lei
2014-07-02 12:18 ` [Qemu-devel] [PATCH v4 3/3] dataplane: submit I/O as a batch Ming Lei
2014-07-03  9:44   ` Kevin Wolf
2014-07-03  9:49     ` Paolo Bonzini
2014-07-03 10:18       ` Kevin Wolf
2014-07-03 12:35   ` Stefan Hajnoczi
2014-07-03 12:37   ` Stefan Hajnoczi
2014-07-03 12:47     ` Ming Lei
2014-07-03  9:25 ` [Qemu-devel] [PATCH v4 0/3] linux-aio: introduce " Kevin Wolf
2014-07-03 12:36 ` Stefan Hajnoczi

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