From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42912) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cw5OS-0003pE-Hl for qemu-devel@nongnu.org; Thu, 06 Apr 2017 07:16:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cw5OP-00017O-E5 for qemu-devel@nongnu.org; Thu, 06 Apr 2017 07:16:00 -0400 Date: Thu, 6 Apr 2017 13:15:43 +0200 From: Kevin Wolf Message-ID: <20170406111543.GE4341@noname.redhat.com> References: <1491320156-4629-1-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1491320156-4629-1-git-send-email-kwolf@redhat.com> Subject: Re: [Qemu-devel] [RFC PATCH for-2.9] block: Ignore guest dev permissions during incoming migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: mreitz@redhat.com, pbonzini@redhat.com, jcody@redhat.com, Ciprian.Barbu@enea.com, Alexandru.Avadanii@enea.com, armband@enea.com, eblake@redhat.com, qemu-devel@nongnu.org Am 04.04.2017 um 17:35 hat Kevin Wolf geschrieben: > Usually guest devices don't like other writers to the same image, so > they use blk_set_perm() to prevent this from happening. In the migration > phase before the VM is actually running, though, they don't have a > problem with writes to the image. On the other hand, storage migration > needs to be able to write to the image in this phase, so the restrictive > blk_set_perm() call of qdev devices breaks it. > > This patch flags all BlockBackends with a qdev device as > blk->disable_perm during incoming migration, which means that the > requested permissions are stored in the BlockBackend, but not actually > applied to its root node yet. > > Once migration has finished and the VM should be resumed, the > permissions are applied. If they cannot be applied (e.g. because the NBD > server used for block migration hasn't been shut down), resuming the VM > fails. > > Signed-off-by: Kevin Wolf Ciprian, can you give this patch a try and report back whether it fixes the storage migration bug you encountered? Kevin