From patchwork Tue Oct 22 07:12:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming-Hung Tsai X-Patchwork-Id: 13845226 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 143DA13AD0 for ; Tue, 22 Oct 2024 07:12:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581180; cv=none; b=mCRtnG8wwIFuUAWA9ZwByhfZhLNDY4HC7aO/mcKX+64Lr6BtSaNqaWg59sCgP8dEvs+IuXn+2ybOB2+yDs7O1wsuZAvuMiZNjG0nbt3zOtw0T6DGnFcKwLUsAKuJTxRVYWMmr2yEKsF2S/pyv6twrIHN6IKJr/hF1BxVVaQ5tjs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581180; c=relaxed/simple; bh=/CiqqNEJ10PN1QWvkqC8BJSrhjzsHEuV9cVXQY+Xujo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=HlSOowbW8GhDkvhxQhDqq5Va3UeT4xrVZUc2REatAkuCao3AxkbpeAWn+oJEvtlRtLlwtfOVSMYJuOYlsioDeiZPxSJD687p4B5Mmuf/4AJdbP+A4Ei8zXHIEfCIP7grpeZ11X9XTAoEp2C+L8ApaNk80a0Cy7f9mdKYpfR1ARg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=e321+mg+; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="e321+mg+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729581178; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=AGi2mNoYkyktpfBeiA2epz+j1luH8CIv62zEtu27bBg=; b=e321+mg+03w1V6dGvEBUD75Xtgrm7NxRWkZkZ73/zsIhSnEufHVrKM/QmXmSTm6f7e8FLV UQsBOA1kN0UcVJ9bxI7JdPTxSkz9uU9ol9mTrwnp30+H1EfQLQzKI8NroOfwat239c4K90 31gmk7mzOZQYp4e5Gv4z51CwqnlBOOg= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-53-fcXokd_FPS2KzMfqi2I_TA-1; Tue, 22 Oct 2024 03:12:54 -0400 X-MC-Unique: fcXokd_FPS2KzMfqi2I_TA-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D125B1955D71; Tue, 22 Oct 2024 07:12:53 +0000 (UTC) Received: from thinkpad.redhat.com (unknown [10.67.24.92]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0363319560A2; Tue, 22 Oct 2024 07:12:44 +0000 (UTC) From: Ming-Hung Tsai To: dm-devel@lists.linux.dev Cc: mpatocka@redhat.com, thornber@redhat.com, heinzm@redhat.com, snitzer@kernel.org, Ming-Hung Tsai Subject: [PATCH 1/5] dm cache: correct the number of origin blocks to match the target length Date: Tue, 22 Oct 2024 15:12:22 +0800 Message-ID: <20241022071222.778553-1-mtsai@redhat.com> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com When creating a cache device, the actual size of the cache origin might be greater than the specified cache target length. In such case, the number of origin blocks should match the cache target length, not the full size of the origin device, since access beyond the cache target is not possible. This issue occurs when reducing the origin device size using lvm, as lvreduce preloads the new cache table before resuming the cache origin, which can result in incorrect sizes for the discard bitset and smq hotspot blocks. Reproduce steps: 1. create a cache device consists of 4096 origin blocks dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. reduce the cache origin to 2048 oblocks, in lvreduce's approach dmsetup reload corig --table "0 262144 linear /dev/sdc 262144" dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup suspend cache dmsetup suspend corig dmsetup suspend cdata dmsetup suspend cmeta dmsetup resume corig dmsetup resume cdata dmsetup resume cmeta dmsetup resume cache 3. shutdown the cache, and check the number of discard blocks in superblock. The value is expected to be 2048, but actually is 4096. dmsetup remove cache corig cdata cmeta dd if=/dev/sdc bs=1c count=8 skip=224 2>/dev/null | hexdump -e '1/8 "%u\n"' Fix by correcting the origin_blocks initialization in cache_create and removing the unused origin_sectors from struct cache_args accordingly. Signed-off-by: Ming-Hung Tsai Fixes: c6b4fcbad044 ("dm: add cache target") --- drivers/md/dm-cache-target.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index aaeeabfab09b..90772b42c234 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2003,7 +2003,6 @@ struct cache_args { sector_t cache_sectors; struct dm_dev *origin_dev; - sector_t origin_sectors; uint32_t block_size; @@ -2084,6 +2083,7 @@ static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as, static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, char **error) { + sector_t origin_sectors; int r; if (!at_least_one_arg(as, error)) @@ -2096,8 +2096,8 @@ static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as, return r; } - ca->origin_sectors = get_dev_size(ca->origin_dev); - if (ca->ti->len > ca->origin_sectors) { + origin_sectors = get_dev_size(ca->origin_dev); + if (ca->ti->len > origin_sectors) { *error = "Device size larger than cached device"; return -EINVAL; } @@ -2407,7 +2407,7 @@ static int cache_create(struct cache_args *ca, struct cache **result) ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL; - origin_blocks = cache->origin_sectors = ca->origin_sectors; + origin_blocks = cache->origin_sectors = ti->len; origin_blocks = block_div(origin_blocks, ca->block_size); cache->origin_blocks = to_oblock(origin_blocks);