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=-15.8 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=unavailable 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 027E3C4338F for ; Wed, 18 Aug 2021 07:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE8EF60ED5 for ; Wed, 18 Aug 2021 07:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238550AbhHRH5u (ORCPT ); Wed, 18 Aug 2021 03:57:50 -0400 Received: from out0.migadu.com ([94.23.1.103]:64121 "EHLO out0.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238229AbhHRH5u (ORCPT ); Wed, 18 Aug 2021 03:57:50 -0400 Subject: Re: [PATCH V2] raid1: ensure write behind bio has less than BIO_MAX_VECS sectors DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1629273432; 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: in-reply-to:in-reply-to:references:references; bh=pyho2UIlpw0vaYkVY2LXF7dfAZZx1UfYbTDceSU2ZY0=; b=LE0v32634CYfcnuc7s8pmfXVUrpIP9yDY4pMHFWVYn9z473RGAB0Hsr5tpEu3tIEMYExWS Udk/cXNLhw8wv1HFee4uyuIPUP++mj3o5775iwuxn+u9MaYGHnN36SLgngzEF6z235yZR0 PduQ5s0OcmYCeEv/m1aMs8Y/rQlaWUQ= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Guoqing Jiang To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-raid@vger.kernel.org, Song Liu , Christoph Hellwig References: <20210818073738.1271033-1-guoqing.jiang@linux.dev> Message-ID: Date: Wed, 18 Aug 2021 15:57:06 +0800 MIME-Version: 1.0 In-Reply-To: <20210818073738.1271033-1-guoqing.jiang@linux.dev> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US 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 Missed to cc Song and Christoph, now actually do it ... On 8/18/21 3:37 PM, Guoqing Jiang wrote: > 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 > > Cc: Song Liu > Cc: Christoph Hellwig > Reported-by: Jens Stutte > Tested-by: Jens Stutte > Signed-off-by: Guoqing Jiang > --- > Hi Jens, > > Could you consider apply this to block tree? Since it depends > on commit 018eca456c4b4dca56aaf1ec27f309c74d0fe246 in block > tree for-next branch, otherwise lkp would complain about compile > issue again. > > Thanks, > Guoqing > > V2 change: > 1. add checking for write-behind case and relevant comments from Christoph. > > drivers/md/raid1.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c > index 3c44c4bb40fc..e8c8e6bb0439 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 +1382,10 @@ 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); > + > + if (test_bit(WriteMostly, &mirror->rdev->flags)) > + write_behind = true; > + > if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { > atomic_inc(&rdev->nr_pending); > blocked_rdev = rdev; > @@ -1454,6 +1459,14 @@ 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);