Re: [Qemu-devel] [PATCH v2 1/6] block-backend: Always notify on blk_eject

From: Eric Blake <eblake@redhat.com>
To: John Snow <jsnow@redhat.com>, qemu-block@nongnu.org
Cc: kwolf@redhat.com, pkrempa@redhat.com, qemu-devel@nongnu.org,
	mreitz@redhat.com, pbonzini@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 1/6] block-backend: Always notify on blk_eject
Date: Mon, 7 Nov 2016 16:01:48 -0600	[thread overview]
Message-ID: <d78b7262-5905-3861-ef32-56bde5417343@redhat.com> (raw)
In-Reply-To: <1478553214-497-2-git-send-email-jsnow@redhat.com>

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On 11/07/2016 03:13 PM, John Snow wrote:
> blk_eject is only used by scsi-disk and atapi, and in both cases we
> only attempt to invoke blk_eject if we have a bona-fide change in
> tray state.
> 
> The "issue" here is that the tray state does not generate a QMP event
> unless there is a medium/BDS attached to the device, so if libvirt et al
> are waiting for a tray event to occur from an empty-but-closed drive,
> software opening that drive will not emit an event and libvirt will
> wait forever.
> 
> Change this by modifying blk_eject to always emit an event, instead of
> conditionally on a "real" backend eject.
> 
> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1373264
> 
> Reported-by: Peter Krempa <pkrempa@redhat.com>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  block/block-backend.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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