From: Christoph Hellwig <hch@lst.de>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 2/2] block: Handle multiwrite errors only when all requests have completed
Date: Fri, 2 Jul 2010 11:40:36 +0200 [thread overview]
Message-ID: <20100702094036.GB21116@lst.de> (raw)
In-Reply-To: <1277994718-14443-3-git-send-email-kwolf@redhat.com>
On Thu, Jul 01, 2010 at 04:31:58PM +0200, Kevin Wolf wrote:
> Don't try to be clever by freeing all temporary data and calling all callbacks
> when the return value (an error) is certain. Doing so has at least two
> important problems:
>
> * The temporary data that is freed (qiov, possibly zero buffer) is still used
> by the requests that have not yet completed.
> * Calling the callbacks for all requests in the multiwrite means for the caller
> that it may free buffers etc. which are still in use.
>
> Just remember the error value and do the cleanup when all requests have
> completed.
Looks good.
prev parent reply other threads:[~2010-07-02 9:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-01 14:31 [Qemu-devel] [PATCH 0/2] block: Fix multiwrite error handling Kevin Wolf
2010-07-01 14:31 ` [Qemu-devel] [PATCH 1/2] block: Fix too early free in multiwrite Kevin Wolf
2010-07-02 8:10 ` Stefan Hajnoczi
2010-07-02 9:38 ` Christoph Hellwig
2010-07-01 14:31 ` [Qemu-devel] [PATCH 2/2] block: Handle multiwrite errors only when all requests have completed Kevin Wolf
2010-07-02 8:33 ` Stefan Hajnoczi
2010-07-02 9:40 ` Christoph Hellwig [this message]
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