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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id g20sm3594900edb.7.2021.03.08.10.23.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 08 Mar 2021 10:23:29 -0800 (PST) Subject: Re: [PATCH] xen-block: Fix removal of backend instance via xenstore To: Anthony PERARD References: <20210308143232.83388-1-anthony.perard@citrix.com> From: Paolo Bonzini Message-ID: <59c6ca73-2f26-e0fa-8b17-a319b2cae8f9@redhat.com> Date: Mon, 8 Mar 2021 19:23:28 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.251, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Stefano Stabellini , qemu-block@nongnu.org, Paul Durrant , qemu-devel@nongnu.org, Maxim Levitsky , Stefan Hajnoczi , xen-devel@lists.xenproject.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 08/03/21 19:14, Anthony PERARD wrote: > On Mon, Mar 08, 2021 at 06:37:38PM +0100, Paolo Bonzini wrote: >> On 08/03/21 18:29, Anthony PERARD wrote: >>>> If nothing else works then I guess it's okay, but why can't you do the >>>> xen_block_drive_destroy from e.g. an unrealize callback? >>> >>> I'm not sure if that's possible. >>> >>> xen_block_device_create/xen_block_device_destroy() is supposed to be >>> equivalent to do those qmp commands: >>> blockdev-add node-name=xvdz-qcow2 driver=qcow2 file={"driver":"file","filename":"disk.qcow2","locking":"off"} >>> device_add id=xvdz driver=xen-disk vdev=xvdz drive=xvdz-qcow2 >>> >>> But I tried to add a call xen_block_drive_destroy from >>> xen_block_unrealize, but that still is called too early, it's called >>> before object_property_del_all() which would delete "drive" and call >>> release_drive() which would free the node. >> >> Can you use blockdev_mark_auto_del? Then you don't have to call >> xen_block_drive_destroy at all. > > There is no legacy_dinfo, so blockdev_mark_auto_del doesn't work. Then I guess it's okay. Perhaps you can rename the function to xen_block_blockdev_destroy so that it's clear it's a blockdev and no drive. Thanks, Paolo