From nobody Thu Oct 2 21:58:20 2025 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 CF84930FC23; Wed, 10 Sep 2025 08:35:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757493314; cv=none; b=aHSoyCJVHTWqU0St2ytezCyc441Fj+H2f4PItSyw/DLyQKd4f1yCxwYC3PPdpaCG5g2gh17FKfowa8LGMoMei/rRSf+qjHaojtHrsDUP+XeDzB8/2Kzwu1ObDAd+FSVZA4ejMVgR951BILA9Gi/bixrv+5DLdoCXHa8wohmT5M8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757493314; c=relaxed/simple; bh=m0Zq0J9d8JUHm+mszd/pi8DixLe/wemrJV20dZtZ2SY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=RIft5YsR5ZIJIC6cnmstCDp5VKiAoyhE//GdUIcSa1fWE0xLOMJjsrgKaT2vtQle5axdGPnWQaDbTv/VJfkJxfAhL1vSIln0xdOEMvtAuYgnmmtF/27xIdLDCltgy24akI2tE5r4J2zE7N3qwf5yDVG6IFOUVWw80GasFsYhZ7E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4cMDXG2np8zKHN9V; Wed, 10 Sep 2025 16:35:10 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 9621C1A084F; Wed, 10 Sep 2025 16:35:10 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgB3wY08OMFo7LgSCA--.53934S4; Wed, 10 Sep 2025 16:35:10 +0800 (CST) From: linan666@huaweicloud.com To: song@kernel.org, yukuai3@huawei.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linan666@huaweicloud.com, yangerkun@huawei.com, yi.zhang@huawei.com Subject: [PATCH] md/raid1: skip recovery of already synced areas Date: Wed, 10 Sep 2025 16:25:44 +0800 Message-Id: <20250910082544.271923-1-linan666@huaweicloud.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgB3wY08OMFo7LgSCA--.53934S4 X-Coremail-Antispam: 1UD129KBjvJXoW7WFW3JryDXFy3uryDtr13Arb_yoW8Cr15pa 13Ja4ag347Ja13JayDZryUGayFya4xGrWxGF17W343Z3sYkFyDWaykXay5WFyDJF4fZw1Y q3ykZ3y3u3W5GaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9G14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1lnxkEFVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I 648v4I1lw4CEc2x0rVAKj4xxMxkF7I0En4kS14v26r126r1DMxAIw28IcxkI7VAKI48JMx C20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAF wI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20x vE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v2 0xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxV W8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUb5ku7UUUUU== X-CM-SenderInfo: polqt0awwwqx5xdzvxpfor3voofrz/ Content-Type: text/plain; charset="utf-8" From: Li Nan When a new disk is added during running recovery, the kernel may restart recovery from the beginning of the device and submit write io to ranges that have already been synchronized. Reproduce: mdadm -CR /dev/md0 -l1 -n3 /dev/sda missing missing mdadm --add /dev/md0 /dev/sdb sleep 10 cat /proc/mdstat # partially synchronized mdadm --add /dev/md0 /dev/sdc cat /proc/mdstat # start from 0 iostat 1 sdb sdc # sdb has io, too If 'rdev->recovery_offset' is ahead of the current recovery sector, read from that device instead of issuing a write. It prevents unnecessary writes while still preserving the chance to back up data if it is the last copy. Signed-off-by: Li Nan --- drivers/md/raid1.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 3e422854cafb..ac5a9b73157a 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2894,7 +2894,8 @@ static sector_t raid1_sync_request(struct mddev *mdde= v, sector_t sector_nr, test_bit(Faulty, &rdev->flags)) { if (i < conf->raid_disks) still_degraded =3D true; - } else if (!test_bit(In_sync, &rdev->flags)) { + } else if (!test_bit(In_sync, &rdev->flags) && + rdev->recovery_offset <=3D sector_nr) { bio->bi_opf =3D REQ_OP_WRITE; bio->bi_end_io =3D end_sync_write; write_targets ++; @@ -2903,6 +2904,9 @@ static sector_t raid1_sync_request(struct mddev *mdde= v, sector_t sector_nr, sector_t first_bad =3D MaxSector; sector_t bad_sectors; =20 + if (!test_bit(In_sync, &rdev->flags)) + good_sectors =3D min(rdev->recovery_offset - sector_nr, + (u64)good_sectors); if (is_badblock(rdev, sector_nr, good_sectors, &first_bad, &bad_sectors)) { if (first_bad > sector_nr) --=20 2.39.2