From nobody Sun Nov 24 20:30:24 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1720699835425405.3537958773684; Thu, 11 Jul 2024 05:10:35 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sRscF-0001gv-7k; Thu, 11 Jul 2024 08:09:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sRsc9-0001Ol-7O; Thu, 11 Jul 2024 08:09:33 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sRsbz-0002s0-91; Thu, 11 Jul 2024 08:09:32 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 0DCD747347; Thu, 11 Jul 2024 14:09:20 +0200 (CEST) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, armbru@redhat.com, eblake@redhat.com, hreitz@redhat.com, kwolf@redhat.com, vsementsov@yandex-team.ru, jsnow@redhat.com Subject: [PATCH v3 1/2] copy-before-write: allow specifying minimum cluster size Date: Thu, 11 Jul 2024 14:09:14 +0200 Message-Id: <20240711120915.310243-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240711120915.310243-1-f.ebner@proxmox.com> References: <20240711120915.310243-1-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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-ZM-MESSAGEID: 1720699837877116600 Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Vladimir Sementsov-Ogievskiy --- Changes in v3: * Pass min_cluster_size option directly without checking has_min_cluster_size, because the default is 0 anyways. * Calculate maximum of passed-in argument and default once at the beginning of block_copy_calculate_cluster_size() * Update warning message to reflect actual value used * Use PRI{i,u}64 macros 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 7e3b378528..59bee538eb 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 096bdbe0aa..80e32db8aa 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4638,12 +4638,18 @@ # @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 9.1) +# # 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 2.39.2