From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D153C4338F for ; Tue, 24 Aug 2021 01:17:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53AA96138B for ; Tue, 24 Aug 2021 01:17:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233559AbhHXBSS (ORCPT ); Mon, 23 Aug 2021 21:18:18 -0400 Received: from out1.migadu.com ([91.121.223.63]:29485 "EHLO out1.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229697AbhHXBSS (ORCPT ); Mon, 23 Aug 2021 21:18:18 -0400 X-Greylist: delayed 2048 seconds by postgrey-1.27 at vger.kernel.org; Mon, 23 Aug 2021 21:18:18 EDT X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1629767854; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=+p/y4+X96U0IPsl0qhnYFKY9iIZpihn52Q9b7rWcaCI=; b=KszRba48ZOjNYm7/U/KFc0BQofezUoJfrriiZTL1fec5SWonTOfVRgriUf2+0d5Z/s33SX UJgCvoDuRHKhRtOOIuza6Ez1QEfxuZwXlBjkMMHDv515L4x8VkQqM7JBXet0zmcm1wfC9J w4UXg2lOhmz0VrsoH34HGHQRZZ6Kimc= From: Guoqing Jiang To: axboe@kernel.dk Cc: song@kernel.org, hch@infradead.org, linux-raid@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH] raid1: ensure write behind bio has less than BIO_MAX_VECS sectors Date: Tue, 24 Aug 2021 09:16:54 +0800 Message-Id: <20210824011654.3829681-1-guoqing.jiang@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: guoqing.jiang@linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org From: Guoqing Jiang We can't split write behind bio with more than BIO_MAX_VECS sectors, otherwise the below call trace was triggered because we could allocate oversized write behind bio later. [ 8.097936] bvec_alloc+0x90/0xc0 [ 8.098934] bio_alloc_bioset+0x1b3/0x260 [ 8.099959] raid1_make_request+0x9ce/0xc50 [raid1] [ 8.100988] ? __bio_clone_fast+0xa8/0xe0 [ 8.102008] md_handle_request+0x158/0x1d0 [md_mod] [ 8.103050] md_submit_bio+0xcd/0x110 [md_mod] [ 8.104084] submit_bio_noacct+0x139/0x530 [ 8.105127] submit_bio+0x78/0x1d0 [ 8.106163] ext4_io_submit+0x48/0x60 [ext4] [ 8.107242] ext4_writepages+0x652/0x1170 [ext4] [ 8.108300] ? do_writepages+0x41/0x100 [ 8.109338] ? __ext4_mark_inode_dirty+0x240/0x240 [ext4] [ 8.110406] do_writepages+0x41/0x100 [ 8.111450] __filemap_fdatawrite_range+0xc5/0x100 [ 8.112513] file_write_and_wait_range+0x61/0xb0 [ 8.113564] ext4_sync_file+0x73/0x370 [ext4] [ 8.114607] __x64_sys_fsync+0x33/0x60 [ 8.115635] do_syscall_64+0x33/0x40 [ 8.116670] entry_SYSCALL_64_after_hwframe+0x44/0xae Thanks for the comment from Christoph. [1]. https://bugs.archlinux.org/task/70992 Reported-by: Jens Stutte Tested-by: Jens Stutte Reviewed-by: Christoph Hellwig Signed-off-by: Guoqing Jiang --- V4 change: 1. fix issue reported by lkp. 2. add Reviewed-by tag. V3 change: 1. add comment before test WriteMostly. 2. reduce line length. V2 change: 1. add checking for write-behind case and relevant comments from Christoph. drivers/md/raid1.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 3c44c4bb40fc..ad51a60f1a93 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1329,6 +1329,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, struct raid1_plug_cb *plug = NULL; int first_clone; int max_sectors; + bool write_behind = false; if (mddev_is_clustered(mddev) && md_cluster_ops->area_resyncing(mddev, WRITE, @@ -1381,6 +1382,15 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, max_sectors = r1_bio->sectors; for (i = 0; i < disks; i++) { struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev); + + /* + * The write-behind io is only attempted on drives marked as + * write-mostly, which means we could allocate write behind + * bio later. + */ + if (rdev && test_bit(WriteMostly, &rdev->flags)) + write_behind = true; + if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { atomic_inc(&rdev->nr_pending); blocked_rdev = rdev; @@ -1454,6 +1464,15 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, goto retry_write; } + /* + * When using a bitmap, we may call alloc_behind_master_bio below. + * alloc_behind_master_bio allocates a copy of the data payload a page + * at a time and thus needs a new bio that can fit the whole payload + * this bio in page sized chunks. + */ + if (write_behind && bitmap) + max_sectors = min_t(int, max_sectors, + BIO_MAX_VECS * PAGE_SECTORS); if (max_sectors < bio_sectors(bio)) { struct bio *split = bio_split(bio, max_sectors, GFP_NOIO, &conf->bio_split); -- 2.25.1