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bh=5kOsbvaV6j0SYAFPC0Xq47Pjz2VvQMB7agejxESRzPg=; b=YYAaAwcnmAx4OXkgSBkHwFyYoUmj+UMXmy/vQy9P+Sthv47ElXb8rtDouBvRE9zAV2ynyx 4Czh8UC/giYKcZLNoIVVaCv6DaDVz8eU7kP4Zne/R7ExkHrs7kIE6NHMnPcGE4JXd9slMR 6SKxbeq/7Wdn24oRZd+nD/zfjFFWSLk= X-MC-Unique: B4R8g_wAMzmLSbdfA5LakA-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org Subject: [PULL 15/58] block/snapshot: stress that we fallback to primary child Date: Thu, 27 Oct 2022 20:31:03 +0200 Message-Id: <20221027183146.463129-16-kwolf@redhat.com> In-Reply-To: <20221027183146.463129-1-kwolf@redhat.com> References: <20221027183146.463129-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.515, 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_H2=-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: , Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1666895674398100001 Content-Type: text/plain; charset="utf-8" From: Vladimir Sementsov-Ogievskiy Actually what we chose is a primary child. Let's stress it in the code. We are going to drop indirect pointer logic here in future. Actually this commit simplifies the future work: we drop use of indirection in the assertion now. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Hanna Reitz Message-Id: <20220726201134.924743-9-vsementsov@yandex-team.ru> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/snapshot.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/block/snapshot.c b/block/snapshot.c index d6f53c3065..75e8d3a937 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -161,21 +161,14 @@ bool bdrv_snapshot_find_by_id_and_name(BlockDriverSta= te *bs, static BdrvChild **bdrv_snapshot_fallback_ptr(BlockDriverState *bs) { BdrvChild **fallback; - BdrvChild *child; + BdrvChild *child =3D bdrv_primary_child(bs); =20 - /* - * The only BdrvChild pointers that are safe to modify (and which - * we can thus return a reference to) are bs->file and - * bs->backing. - */ - fallback =3D &bs->file; - if (!*fallback && bs->drv && bs->drv->is_filter) { - fallback =3D &bs->backing; - } - - if (!*fallback) { + /* We allow fallback only to primary child */ + if (!child) { return NULL; } + fallback =3D (child =3D=3D bs->file ? &bs->file : &bs->backing); + assert(*fallback =3D=3D child); =20 /* * Check that there are no other children that would need to be @@ -309,15 +302,12 @@ int bdrv_snapshot_goto(BlockDriverState *bs, } =20 /* - * fallback_ptr is &bs->file or &bs->backing. *fallback_ptr - * was closed above and set to NULL, but the .bdrv_open() call - * has opened it again, because we set the respective option - * (with the qdict_put_str() call above). - * Assert that .bdrv_open() has attached some child on - * *fallback_ptr, and that it has attached the one we wanted - * it to (i.e., fallback_bs). + * fallback was a primary child. It was closed above and set to NU= LL, + * but the .bdrv_open() call has opened it again, because we set t= he + * respective option (with the qdict_put_str() call above). + * Assert that .bdrv_open() has attached the right BDS as primary = child. */ - assert(*fallback_ptr && fallback_bs =3D=3D (*fallback_ptr)->bs); + assert(bdrv_primary_bs(bs) =3D=3D fallback_bs); bdrv_unref(fallback_bs); return ret; } --=20 2.37.3