From: Kevin Wolf <kwolf@redhat.com>
To: Nicholas Thomas <nick@bytemark.co.uk>
Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH] block/curl: Handle failed reads gracefully.
Date: Fri, 19 Aug 2011 01:00:33 +0200 [thread overview]
Message-ID: <4E4D9991.60707@redhat.com> (raw)
In-Reply-To: <1313398834.17401.135.camel@desk4.office.bytemark.co.uk>
Am 15.08.2011 11:00, schrieb Nicholas Thomas:
> Current behaviour if a read fails is for the acb to not get finished.
> This causes an infinite loop in bdrv_read_em (block.c). The read failure
> never gets reported to the guest and if the error condition clears, the
> process never recovers.
>
> With this patch, when curl reports a failure we finish the acb as a
> failure. This results in the guest receiving an I/O error (rather than
> the read hanging indefinitely) and if the error condition subsequently
> clears, retries work as expected.
>
> The simplest test is to put an ISO on a web server you have control over
> and open it with qemu-io. Then move the ISO out of the way and attempt
> to read some data - you should see behaviour matching the above.
>
> Signed-off-by: Nick Thomas <nick@bytemark.co.uk>
Thanks, applied to the block branch.
Kevin
prev parent reply other threads:[~2011-08-18 22:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-15 9:00 [Qemu-trivial] [PATCH] block/curl: Handle failed reads gracefully Nicholas Thomas
2011-08-18 23:00 ` Kevin Wolf [this message]
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