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Wed, 14 May 2025 17:06:09 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.207]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 94C321955F24; Wed, 14 May 2025 17:06:05 +0000 (UTC) Date: Wed, 14 May 2025 19:06:02 +0200 From: Kevin Wolf To: Fiona Ebner Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, den@virtuozzo.com, andrey.drobyshev@virtuozzo.com, hreitz@redhat.com, stefanha@redhat.com, eblake@redhat.com, jsnow@redhat.com, vsementsov@yandex-team.ru Subject: Re: [PATCH 05/11] block: move drain outside of read-locked bdrv_inactivate_recurse() Message-ID: References: <20250508140936.3344485-1-f.ebner@proxmox.com> <20250508140936.3344485-6-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250508140936.3344485-6-f.ebner@proxmox.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.686, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 08.05.2025 um 16:09 hat Fiona Ebner geschrieben: > This is in preparation to mark bdrv_drained_begin() as GRAPH_UNLOCKED. > > More granular draining is not trivially possible, because > bdrv_inactivate_recurse() can recursively call itself. > > Signed-off-by: Fiona Ebner > --- > block.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/block.c b/block.c > index c7c26533c9..10052027cd 100644 > --- a/block.c > +++ b/block.c > @@ -6991,6 +6991,8 @@ bdrv_inactivate_recurse(BlockDriverState *bs, bool top_level) > int ret; > uint64_t cumulative_perms, cumulative_shared_perms; > > + assert(qatomic_read(&bs->quiesce_counter) > 0); > + > GLOBAL_STATE_CODE(); > > if (!bs->drv) { > @@ -7036,9 +7038,7 @@ bdrv_inactivate_recurse(BlockDriverState *bs, bool top_level) > return -EPERM; > } > > - bdrv_drained_begin(bs); > bs->open_flags |= BDRV_O_INACTIVE; > - bdrv_drained_end(bs); > > /* > * Update permissions, they may differ for inactive nodes. > @@ -7063,14 +7063,20 @@ int bdrv_inactivate(BlockDriverState *bs, Error **errp) > int ret; > > GLOBAL_STATE_CODE(); > - GRAPH_RDLOCK_GUARD_MAINLOOP(); > + > + bdrv_drain_all_begin(); > + bdrv_graph_rdlock_main_loop(); > > if (bdrv_has_bds_parent(bs, true)) { > error_setg(errp, "Node has active parent node"); > + bdrv_graph_rdunlock_main_loop(); > + bdrv_drain_all_end(); > return -EPERM; > } > > ret = bdrv_inactivate_recurse(bs, true); > + bdrv_graph_rdunlock_main_loop(); > + bdrv_drain_all_end(); > if (ret < 0) { > error_setg_errno(errp, -ret, "Failed to inactivate node"); > return ret; This might be another one that would become a bit clearer if you put the unlock/drain_end at the end and use a goto out for the error cases. Kevin