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(unknown [2a02:6b8:b081:b737::1:2c]) by mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id WhU2Sb1IXiE0-cyZRRwx5; Mon, 30 Sep 2024 11:43:48 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1727685828; bh=CA0ozR2MoFs8iqJMkGwT6szoTB2uzbt1omtnLOIN2UU=; h=Message-Id:Date:In-Reply-To:Cc:Subject:References:To:From; b=aJrhtueKuTAtkyxJ2JKTMDozG9n52O516UkIclLfZ3lUUhA4VBt9teCcpdvyUUp6B f+XNDDHNsM862fNPl1vPL42GfqY/5WjdLJCD+a+UyTrlwx9Qrm6c1N7aj1C2a61qvf h9CuHURWHjW7Oe43caiDJCWJ546mwUPY7E1eJRiw= Authentication-Results: mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net; dkim=pass header.i=@yandex-team.ru From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, vsementsov@yandex-team.ru, peter.maydell@linaro.org, Fiona Ebner , Markus Armbruster Subject: [PULL 1/5] copy-before-write: allow specifying minimum cluster size Date: Mon, 30 Sep 2024 11:43:21 +0300 Message-Id: <20240930084325.187606-2-vsementsov@yandex-team.ru> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240930084325.187606-1-vsementsov@yandex-team.ru> References: <20240930084325.187606-1-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Yandex-Filter: 1 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=2a02:6b8:c0e:500:1:45:d181:df01; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1a.mail.yandex.net 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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 @yandex-team.ru) X-ZM-MESSAGEID: 1727685923102116600 Content-Type: text/plain; charset="utf-8" From: Fiona Ebner In the context of backup fleecing, discarding the source will not work when the fleecing image has a larger granularity than the one used for block-copy operations (can happen if the backup target has smaller cluster size), because cbw_co_pdiscard_snapshot() will align down the discard requests and thus effectively ignore then. To make @discard-source work in such a scenario, allow specifying the minimum cluster size used for block-copy operations and thus in particular also the granularity for discard requests to the source. The type 'size' (corresponding to uint64_t in C) is used in QAPI to rule out negative inputs and for consistency with already existing @cluster-size parameters. Since block_copy_calculate_cluster_size() uses int64_t for its result, a check that the input is not too large is added in block_copy_state_new() before calling it. The calculation in block_copy_calculate_cluster_size() is done in the target int64_t type. Suggested-by: Vladimir Sementsov-Ogievskiy Acked-by: Markus Armbruster (QAPI schema) Signed-off-by: Fiona Ebner Message-Id: <20240711120915.310243-2-f.ebner@proxmox.com> [vsementsov: switch version to 9.2 in QAPI doc] Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Vladimir Sementsov-Ogievskiy --- block/block-copy.c | 36 ++++++++++++++++++++++++++---------- block/copy-before-write.c | 5 ++++- include/block/block-copy.h | 1 + qapi/block-core.json | 8 +++++++- 4 files changed, 38 insertions(+), 12 deletions(-) diff --git a/block/block-copy.c b/block/block-copy.c index cc618e4561..93eb1b2664 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -310,6 +310,7 @@ void block_copy_set_copy_opts(BlockCopyState *s, bool u= se_copy_range, } =20 static int64_t block_copy_calculate_cluster_size(BlockDriverState *target, + int64_t min_cluster_size, Error **errp) { int ret; @@ -319,6 +320,9 @@ static int64_t block_copy_calculate_cluster_size(BlockD= riverState *target, GLOBAL_STATE_CODE(); GRAPH_RDLOCK_GUARD_MAINLOOP(); =20 + min_cluster_size =3D MAX(min_cluster_size, + (int64_t)BLOCK_COPY_CLUSTER_SIZE_DEFAULT); + target_does_cow =3D bdrv_backing_chain_next(target); =20 /* @@ -329,13 +333,13 @@ static int64_t block_copy_calculate_cluster_size(Bloc= kDriverState *target, ret =3D bdrv_get_info(target, &bdi); if (ret =3D=3D -ENOTSUP && !target_does_cow) { /* Cluster size is not defined */ - warn_report("The target block device doesn't provide " - "information about the block size and it doesn't have = a " - "backing file. The default block size of %u bytes is " - "used. If the actual block size of the target exceeds " - "this default, the backup may be unusable", - BLOCK_COPY_CLUSTER_SIZE_DEFAULT); - return BLOCK_COPY_CLUSTER_SIZE_DEFAULT; + warn_report("The target block device doesn't provide information a= bout " + "the block size and it doesn't have a backing file. Th= e " + "(default) block size of %" PRIi64 " bytes is used. If= the " + "actual block size of the target exceeds this value, t= he " + "backup may be unusable", + min_cluster_size); + return min_cluster_size; } else if (ret < 0 && !target_does_cow) { error_setg_errno(errp, -ret, "Couldn't determine the cluster size of the target image, " @@ -345,16 +349,17 @@ static int64_t block_copy_calculate_cluster_size(Bloc= kDriverState *target, return ret; } else if (ret < 0 && target_does_cow) { /* Not fatal; just trudge on ahead. */ - return BLOCK_COPY_CLUSTER_SIZE_DEFAULT; + return min_cluster_size; } =20 - return MAX(BLOCK_COPY_CLUSTER_SIZE_DEFAULT, bdi.cluster_size); + return MAX(min_cluster_size, bdi.cluster_size); } =20 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, BlockDriverState *copy_bitmap_bs, const BdrvDirtyBitmap *bitmap, bool discard_source, + uint64_t min_cluster_size, Error **errp) { ERRP_GUARD(); @@ -365,7 +370,18 @@ BlockCopyState *block_copy_state_new(BdrvChild *source= , BdrvChild *target, =20 GLOBAL_STATE_CODE(); =20 - cluster_size =3D block_copy_calculate_cluster_size(target->bs, errp); + if (min_cluster_size > INT64_MAX) { + error_setg(errp, "min-cluster-size too large: %" PRIu64 " > %" PRI= i64, + min_cluster_size, INT64_MAX); + return NULL; + } else if (min_cluster_size && !is_power_of_2(min_cluster_size)) { + error_setg(errp, "min-cluster-size needs to be a power of 2"); + return NULL; + } + + cluster_size =3D block_copy_calculate_cluster_size(target->bs, + (int64_t)min_cluster_= size, + errp); if (cluster_size < 0) { return NULL; } diff --git a/block/copy-before-write.c b/block/copy-before-write.c index 853e01a1eb..a919b1f41b 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -417,6 +417,7 @@ static BlockdevOptions *cbw_parse_options(QDict *option= s, Error **errp) qdict_extract_subqdict(options, NULL, "bitmap"); qdict_del(options, "on-cbw-error"); qdict_del(options, "cbw-timeout"); + qdict_del(options, "min-cluster-size"); =20 out: visit_free(v); @@ -476,8 +477,10 @@ static int cbw_open(BlockDriverState *bs, QDict *optio= ns, int flags, bs->file->bs->supported_zero_flags); =20 s->discard_source =3D flags & BDRV_O_CBW_DISCARD_SOURCE; + s->bcs =3D block_copy_state_new(bs->file, s->target, bs, bitmap, - flags & BDRV_O_CBW_DISCARD_SOURCE, errp); + flags & BDRV_O_CBW_DISCARD_SOURCE, + opts->min_cluster_size, errp); if (!s->bcs) { error_prepend(errp, "Cannot create block-copy-state: "); return -EINVAL; diff --git a/include/block/block-copy.h b/include/block/block-copy.h index bdc703bacd..dd5cc82f3b 100644 --- a/include/block/block-copy.h +++ b/include/block/block-copy.h @@ -28,6 +28,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, B= drvChild *target, BlockDriverState *copy_bitmap_bs, const BdrvDirtyBitmap *bitmap, bool discard_source, + uint64_t min_cluster_size, Error **errp); =20 /* Function should be called prior any actual copy request */ diff --git a/qapi/block-core.json b/qapi/block-core.json index 9f6dd59298..6751022428 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4639,12 +4639,18 @@ # @on-cbw-error parameter will decide how this failure is handled. # Default 0. (Since 7.1) # +# @min-cluster-size: Minimum size of blocks used by copy-before-write +# operations. Has to be a power of 2. No effect if smaller than +# the maximum of the target's cluster size and 64 KiB. Default 0. +# (Since 9.2) +# # Since: 6.2 ## { 'struct': 'BlockdevOptionsCbw', 'base': 'BlockdevOptionsGenericFormat', 'data': { 'target': 'BlockdevRef', '*bitmap': 'BlockDirtyBitmap', - '*on-cbw-error': 'OnCbwError', '*cbw-timeout': 'uint32' } } + '*on-cbw-error': 'OnCbwError', '*cbw-timeout': 'uint32', + '*min-cluster-size': 'size' } } =20 ## # @BlockdevOptions: --=20 2.34.1