From patchwork Tue May 28 12:01:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 13676568 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 23AB8C41513 for ; Tue, 28 May 2024 12:02:26 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sBvWP-0002TH-OC; Tue, 28 May 2024 08:01:41 -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 1sBvWL-0002PG-0t; Tue, 28 May 2024 08:01:38 -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 1sBvWH-0004DN-Bo; Tue, 28 May 2024 08:01:36 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 42219441CE; Tue, 28 May 2024 14:01:19 +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 v2 1/2] copy-before-write: allow specifying minimum cluster size Date: Tue, 28 May 2024 14:01:13 +0200 Message-Id: <20240528120114.344416-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240528120114.344416-1-f.ebner@proxmox.com> References: <20240528120114.344416-1-f.ebner@proxmox.com> MIME-Version: 1.0 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, 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 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 Signed-off-by: Fiona Ebner Acked-by: Markus Armbruster Reviewed-by: Vladimir Sementsov-Ogievskiy --- Changes in v2: * Use 'size' type in QAPI. * Remove option in cbw_parse_options(), i.e. before parsing generic blockdev options. block/block-copy.c | 22 ++++++++++++++++++---- block/copy-before-write.c | 10 +++++++++- include/block/block-copy.h | 1 + qapi/block-core.json | 8 +++++++- 4 files changed, 35 insertions(+), 6 deletions(-) diff --git a/block/block-copy.c b/block/block-copy.c index 7e3b378528..36eaecaaf4 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -310,6 +310,7 @@ void block_copy_set_copy_opts(BlockCopyState *s, bool use_copy_range, } static int64_t block_copy_calculate_cluster_size(BlockDriverState *target, + int64_t min_cluster_size, Error **errp) { int ret; @@ -335,7 +336,7 @@ static int64_t block_copy_calculate_cluster_size(BlockDriverState *target, "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; + return MAX(min_cluster_size, (int64_t)BLOCK_COPY_CLUSTER_SIZE_DEFAULT); } else if (ret < 0 && !target_does_cow) { error_setg_errno(errp, -ret, "Couldn't determine the cluster size of the target image, " @@ -345,16 +346,18 @@ static int64_t block_copy_calculate_cluster_size(BlockDriverState *target, return ret; } else if (ret < 0 && target_does_cow) { /* Not fatal; just trudge on ahead. */ - return BLOCK_COPY_CLUSTER_SIZE_DEFAULT; + return MAX(min_cluster_size, (int64_t)BLOCK_COPY_CLUSTER_SIZE_DEFAULT); } - return MAX(BLOCK_COPY_CLUSTER_SIZE_DEFAULT, bdi.cluster_size); + return MAX(min_cluster_size, + (int64_t)MAX(BLOCK_COPY_CLUSTER_SIZE_DEFAULT, bdi.cluster_size)); } 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 +368,18 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, GLOBAL_STATE_CODE(); - cluster_size = block_copy_calculate_cluster_size(target->bs, errp); + if (min_cluster_size > INT64_MAX) { + error_setg(errp, "min-cluster-size too large: %lu > %ld", + 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 = 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 cd65524e26..ef0bc4dcfe 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -417,6 +417,7 @@ static BlockdevOptions *cbw_parse_options(QDict *options, 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"); out: visit_free(v); @@ -432,6 +433,7 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags, BDRVCopyBeforeWriteState *s = bs->opaque; BdrvDirtyBitmap *bitmap = NULL; int64_t cluster_size; + uint64_t min_cluster_size = 0; g_autoptr(BlockdevOptions) full_opts = NULL; BlockdevOptionsCbw *opts; int ret; @@ -476,8 +478,14 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags, bs->file->bs->supported_zero_flags); s->discard_source = flags & BDRV_O_CBW_DISCARD_SOURCE; + + if (opts->has_min_cluster_size) { + min_cluster_size = opts->min_cluster_size; + } + s->bcs = block_copy_state_new(bs->file, s->target, bs, bitmap, - flags & BDRV_O_CBW_DISCARD_SOURCE, errp); + flags & BDRV_O_CBW_DISCARD_SOURCE, + 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, BdrvChild *target, BlockDriverState *copy_bitmap_bs, const BdrvDirtyBitmap *bitmap, bool discard_source, + uint64_t min_cluster_size, Error **errp); /* Function should be called prior any actual copy request */ diff --git a/qapi/block-core.json b/qapi/block-core.json index df5e07debd..8fc0a4b234 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4642,12 +4642,18 @@ # @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' } } ## # @BlockdevOptions: