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bh=6sfjBtg43d8qTRgHVSUXIOWhcEaXJBXhjGAOPyBdwgo=; b=OnP4lVErIml7B1UOUopUBWVIQWAgkazxQTgJtj0lrfLh9+o0Tpt2H+25mGGMTllvaYfiOq rMADFYsziouMULkj+nSwzObnyauT+BgmGlc/IrS8sOM4GQspyOt14LOVo/4KuJsiVMBrOb 5kjp5cbtAZSgduQjizrumGpkHItVVdw= X-MC-Unique: IXIPfhyGOrGwN5MaOltwRg-1 From: Kevin Wolf To: qemu-devel@nongnu.org Cc: kwolf@redhat.com Subject: [PULL 12/25] block: Mark bdrv_cow_child() and callers GRAPH_RDLOCK Date: Tue, 7 Nov 2023 19:45:52 +0100 Message-ID: <20231107184605.236540-13-kwolf@redhat.com> In-Reply-To: <20231107184605.236540-1-kwolf@redhat.com> References: <20231107184605.236540-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 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: -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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: 1699382941439100005 Content-Type: text/plain; charset="utf-8" This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_cow_child() need to hold a reader lock for the graph because it accesses bs->backing. Signed-off-by: Kevin Wolf Message-ID: <20231027155333.420094-13-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- include/block/block_int-io.h | 5 +++-- block/stream.c | 2 +- qemu-img.c | 11 ++++++++--- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index 17547a2dab..4a7cf2b4fd 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -130,14 +130,15 @@ bdrv_co_refresh_total_sectors(BlockDriverState *bs, i= nt64_t hint); int co_wrapper_mixed_bdrv_rdlock bdrv_refresh_total_sectors(BlockDriverState *bs, int64_t hint); =20 -BdrvChild *bdrv_cow_child(BlockDriverState *bs); +BdrvChild * GRAPH_RDLOCK bdrv_cow_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_filter_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_filter_or_cow_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_primary_child(BlockDriverState *bs); BlockDriverState * GRAPH_RDLOCK bdrv_skip_filters(BlockDriverState *bs); BlockDriverState * GRAPH_RDLOCK bdrv_backing_chain_next(BlockDriverState *= bs); =20 -static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs) +static inline BlockDriverState * GRAPH_RDLOCK +bdrv_cow_bs(BlockDriverState *bs) { IO_CODE(); return child_bs(bdrv_cow_child(bs)); diff --git a/block/stream.c b/block/stream.c index c32c98339a..3f5d773535 100644 --- a/block/stream.c +++ b/block/stream.c @@ -90,7 +90,7 @@ static int stream_prepare(Job *job) unfiltered_base =3D bdrv_skip_filters(base); bdrv_graph_rdunlock_main_loop(); =20 - if (bdrv_cow_child(unfiltered_bs)) { + if (unfiltered_bs_cow) { const char *base_id =3D NULL, *base_fmt =3D NULL; if (unfiltered_base) { base_id =3D s->backing_file_str ?: unfiltered_base->filename; diff --git a/qemu-img.c b/qemu-img.c index 33f3ab5fba..5a77f67719 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3541,7 +3541,7 @@ static int img_rebase(int argc, char **argv) uint8_t *buf_old =3D NULL; uint8_t *buf_new =3D NULL; BlockDriverState *bs =3D NULL, *prefix_chain_bs =3D NULL; - BlockDriverState *unfiltered_bs; + BlockDriverState *unfiltered_bs, *unfiltered_bs_cow; BlockDriverInfo bdi =3D {0}; char *filename; const char *fmt, *cache, *src_cache, *out_basefmt, *out_baseimg; @@ -3675,6 +3675,7 @@ static int img_rebase(int argc, char **argv) =20 bdrv_graph_rdlock_main_loop(); unfiltered_bs =3D bdrv_skip_filters(bs); + unfiltered_bs_cow =3D bdrv_cow_bs(unfiltered_bs); bdrv_graph_rdunlock_main_loop(); =20 if (compress && !block_driver_can_compress(unfiltered_bs->drv)) { @@ -3710,7 +3711,11 @@ static int img_rebase(int argc, char **argv) /* For safe rebasing we need to compare old and new backing file */ if (!unsafe) { QDict *options =3D NULL; - BlockDriverState *base_bs =3D bdrv_cow_bs(unfiltered_bs); + BlockDriverState *base_bs; + + bdrv_graph_rdlock_main_loop(); + base_bs =3D bdrv_cow_bs(unfiltered_bs); + bdrv_graph_rdunlock_main_loop(); =20 if (base_bs) { blk_old_backing =3D blk_new(qemu_get_aio_context(), @@ -3876,7 +3881,7 @@ static int img_rebase(int argc, char **argv) * If cluster wasn't changed since prefix_chain, we don't = need * to take action */ - ret =3D bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs), + ret =3D bdrv_is_allocated_above(unfiltered_bs_cow, prefix_chain_bs, false, offset, n, &n); if (ret < 0) { --=20 2.41.0