From: Kevin Wolf <kwolf@redhat.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: jsnow@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org,
mreitz@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 2/2] blockjob: use blk_new_pinned in block_job_create
Date: Wed, 5 Jun 2019 19:11:37 +0200 [thread overview]
Message-ID: <20190605171137.GC5491@linux.fritz.box> (raw)
In-Reply-To: <20190605123229.92848-3-vsementsov@virtuozzo.com>
Am 05.06.2019 um 14:32 hat Vladimir Sementsov-Ogievskiy geschrieben:
> child_role job already has .stay_at_node=true, so on bdrv_replace_node
> operation these child are unchanged. Make block job blk behave in same
> manner, to avoid inconsistent intermediate graph states and workarounds
> like in mirror.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This feels dangerous. It does what you want it to do if the only graph
change below the BlockBackend is the one in mirror_exit_common. But the
user could also take a snapshot, or in the future hopefully insert a
filter node, and you would then want the BlockBackend to move.
To be honest, even BdrvChildRole.stay_at_node is a bit of a hack. But at
least it's only used for permissions and not for the actual data flow.
Kevin
next prev parent reply other threads:[~2019-06-05 17:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 12:32 [Qemu-devel] [PATCH v2 0/2] introduce pinned blk Vladimir Sementsov-Ogievskiy
2019-06-05 12:32 ` [Qemu-devel] [PATCH v2 1/2] block: " Vladimir Sementsov-Ogievskiy
2019-06-05 12:32 ` [Qemu-devel] [PATCH v2 2/2] blockjob: use blk_new_pinned in block_job_create Vladimir Sementsov-Ogievskiy
2019-06-05 17:11 ` Kevin Wolf [this message]
2019-06-05 17:16 ` Vladimir Sementsov-Ogievskiy
2019-06-06 10:05 ` Kevin Wolf
2019-06-06 12:29 ` Vladimir Sementsov-Ogievskiy
2019-06-06 13:06 ` Kevin Wolf
2019-06-06 13:25 ` Vladimir Sementsov-Ogievskiy
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