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bh=BR9QUUGdhAAxg3GK1bTg935xvmOqd5Yhf7t1CpbJhcs=; b=Lbo8NVZx39UzK/x/Uh6h/LdG4+QrpyLQY3X4mJpzkAfUCCuCwGP3zSV9gqCBKxyGX8cNWS eC/5JGZGs9p+CeMe+uGKZdjXaSemc7GMhgzUANpJMyRAXyP9pCVEqVy09c056lJK2/igiL 9pD85P7mpcPxIJ/qdhLqt2XH/qc6PTo= X-MC-Unique: ATozQVssPiCkidLXe3ISbg-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, eesposit@redhat.com, eblake@redhat.com, pbonzini@redhat.com, vsementsov@yandex-team.ru, qemu-devel@nongnu.org Subject: [PATCH 06/24] block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK Date: Fri, 27 Oct 2023 17:53:15 +0200 Message-ID: <20231027155333.420094-7-kwolf@redhat.com> In-Reply-To: <20231027155333.420094-1-kwolf@redhat.com> References: <20231027155333.420094-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 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=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1698422104746100007 Content-Type: text/plain; charset="utf-8" This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- include/block/block_int-io.h | 3 ++- block.c | 31 ++++++++++++++++++------------- block/stream.c | 4 ++++ blockdev.c | 2 +- nbd/server.c | 6 ++++++ 5 files changed, 31 insertions(+), 15 deletions(-) diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index 26bff94e4e..6800af7590 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -150,7 +150,8 @@ bdrv_filter_bs(BlockDriverState *bs) return child_bs(bdrv_filter_child(bs)); } =20 -static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs) +static inline BlockDriverState * GRAPH_RDLOCK +bdrv_filter_or_cow_bs(BlockDriverState *bs) { IO_CODE(); return child_bs(bdrv_filter_or_cow_child(bs)); diff --git a/block.c b/block.c index 5f92eb4950..a6060eddbc 100644 --- a/block.c +++ b/block.c @@ -5435,17 +5435,6 @@ static int bdrv_replace_node_common(BlockDriverState= *from, =20 GLOBAL_STATE_CODE(); =20 - if (detach_subchain) { - assert(bdrv_chain_contains(from, to)); - assert(from !=3D to); - for (to_cow_parent =3D from; - bdrv_filter_or_cow_bs(to_cow_parent) !=3D to; - to_cow_parent =3D bdrv_filter_or_cow_bs(to_cow_parent)) - { - ; - } - } - /* Make sure that @from doesn't go away until we have successfully att= ached * all of its parents to @to. */ bdrv_ref(from); @@ -5457,6 +5446,17 @@ static int bdrv_replace_node_common(BlockDriverState= *from, =20 bdrv_graph_wrlock(to); =20 + if (detach_subchain) { + assert(bdrv_chain_contains(from, to)); + assert(from !=3D to); + for (to_cow_parent =3D from; + bdrv_filter_or_cow_bs(to_cow_parent) !=3D to; + to_cow_parent =3D bdrv_filter_or_cow_bs(to_cow_parent)) + { + ; + } + } + /* * Do the replacement without permission update. * Replacement may influence the permissions, we should calculate new @@ -5504,10 +5504,14 @@ int bdrv_replace_node(BlockDriverState *from, Block= DriverState *to, =20 int bdrv_drop_filter(BlockDriverState *bs, Error **errp) { + BlockDriverState *child_bs; + GLOBAL_STATE_CODE(); + bdrv_graph_rdlock_main_loop(); + child_bs =3D bdrv_filter_or_cow_bs(bs); + bdrv_graph_rdunlock_main_loop(); =20 - return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, t= rue, - errp); + return bdrv_replace_node_common(bs, child_bs, true, true, errp); } =20 /* @@ -6509,6 +6513,7 @@ bool bdrv_chain_contains(BlockDriverState *top, Block= DriverState *base) { =20 GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); =20 while (top && top !=3D base) { top =3D bdrv_filter_or_cow_bs(top); diff --git a/block/stream.c b/block/stream.c index 51333e460b..2781441191 100644 --- a/block/stream.c +++ b/block/stream.c @@ -60,6 +60,8 @@ static int stream_prepare(Job *job) Error *local_err =3D NULL; int ret =3D 0; =20 + GLOBAL_STATE_CODE(); + /* We should drop filter at this point, as filter hold the backing cha= in */ bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs =3D NULL; @@ -78,8 +80,10 @@ static int stream_prepare(Job *job) bdrv_drained_begin(unfiltered_bs_cow); } =20 + bdrv_graph_rdlock_main_loop(); base =3D bdrv_filter_or_cow_bs(s->above_base); unfiltered_base =3D bdrv_skip_filters(base); + bdrv_graph_rdunlock_main_loop(); =20 if (bdrv_cow_child(unfiltered_bs)) { const char *base_id =3D NULL, *base_fmt =3D NULL; diff --git a/blockdev.c b/blockdev.c index 25c6c6e8d3..240834b6d4 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2492,8 +2492,8 @@ void qmp_block_stream(const char *job_id, const char = *device, /* * Check for op blockers in the whole chain between bs and base (or bo= ttom) */ - iter_end =3D bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; bdrv_graph_rdlock_main_loop(); + iter_end =3D bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; for (iter =3D bs; iter && iter !=3D iter_end; iter =3D bdrv_filter_or_cow_bs(iter)) { diff --git a/nbd/server.c b/nbd/server.c index 859c163d19..895cf0a752 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1689,6 +1689,7 @@ static int nbd_export_create(BlockExport *blk_exp, Bl= ockExportOptions *exp_args, size_t i; int ret; =20 + GLOBAL_STATE_CODE(); assert(exp_args->type =3D=3D BLOCK_EXPORT_TYPE_NBD); =20 if (!nbd_server_is_running()) { @@ -1743,6 +1744,8 @@ static int nbd_export_create(BlockExport *blk_exp, Bl= ockExportOptions *exp_args, } exp->size =3D QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); =20 + bdrv_graph_rdlock_main_loop(); + for (bitmaps =3D arg->bitmaps; bitmaps; bitmaps =3D bitmaps->next) { exp->nr_export_bitmaps++; } @@ -1825,9 +1828,12 @@ static int nbd_export_create(BlockExport *blk_exp, B= lockExportOptions *exp_args, =20 QTAILQ_INSERT_TAIL(&exports, exp, next); =20 + bdrv_graph_rdunlock_main_loop(); + return 0; =20 fail: + bdrv_graph_rdunlock_main_loop(); g_free(exp->export_bitmaps); g_free(exp->name); g_free(exp->description); --=20 2.41.0