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Date: Wed, 12 Nov 2008 14:03:50 +0100
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [patch] Fix block I/O hang.
References: <4919B46C.3040804@redhat.com> <4919B79A.5030402@codemonkey.ws>
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To: qemu-devel@nongnu.org

Anthony Liguori wrote:
> Gerd Hoffmann wrote:
>>   Hi,
>>
>> $subject says all.
>>
>> please apply,
>>   Gerd

> Under what circumstances?  posix_aio_read() is only invoked from a
> select callback.  This means there should be data available to be read.

Well, there are *two* select loops:  main_loop_wait() and
qemu_aio_wait().  Calling sync block i/o functions from a i/o handler
causes the two select loops run nested => boom.

cheers,
  Gerd