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Lunev" Cc: qemu-devel@nongnu.org, Peter Xu , Fabiano Rosas , Juraj Marcin Subject: Re: [PATCH v2 2/5] migration/postcopy: set destination postcopy-active in the run BH Message-ID: References: <20261110183257.2930908-1-den@openvz.org> <20261110183257.2930908-3-den@openvz.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261110183257.2930908-3-den@openvz.org> User-Agent: NeoMutt/20260616 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 5 X-Spam_score: 0.5 X-Spam_bar: / X-Spam_report: (0.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 10, 2026 at 07:32:54PM +0100, Denis V. Lunev wrote: > From: Denis V. Lunev > > Commit 7b842fe354c ("migration: Introduce POSTCOPY_DEVICE state") made > the destination enter POSTCOPY_ACTIVE in loadvm_postcopy_handle_run(), > before it schedules loadvm_postcopy_handle_run_bh(), and only the BH > starts the VM or moves it to RUN_STATE_PAUSED. Management reacting to > the destination's postcopy-active event can therefore still find the > VM in RUN_STATE_INMIGRATE, where blockdev-add creates inactive nodes > and attaching a device to them fails with "Block node is read-only". > > Move the transition to the end of the run BH, after vm_start() or > runstate_set(), as process_incoming_migration_bh() does for precopy > COMPLETED. Without a return path the listen thread enters > POSTCOPY_ACTIVE directly, and the fast snapshot load path switches > right after scheduling the BH; in both cases the state is no longer > POSTCOPY_DEVICE when the BH runs and the transition is a no-op. > > Signed-off-by: Denis V. Lunev > Cc: Peter Xu > Cc: Fabiano Rosas > Cc: Juraj Marcin > --- > migration/savevm.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) I'll defer to Peter's judgment on this one and 4/5, but the descriptions in the cover letter and commit message make sense to me. Meanwhile, I'm setting up to play with 3 and 5/5 to see if I can review those tests for catching the issues documented here, even if I'm less comfortable being the sole reviewer on the code changes that got them to pass. -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org