From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 68AA435E1A1; Wed, 24 Jun 2026 06:46:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782283596; cv=none; b=ngqOJEUenyAMiIyJkD1SBggHtxwTERha6sNkM0UMVr3anB6LY6ECr0Ide9VI0TPbJg0TGeXullUPASNqiPtKm1gRnHGHwtQp10UOJoAfu73bRWPZy0DNv/bH0ICbXwNSYyT8fKrnT90XMDbwi/Zn29cAxRHLDfkrM3aQcp2uyk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782283596; c=relaxed/simple; bh=JohLVIOOj0NauXvt4WSRy3GjttDcZozn8cwIQ7iH/es=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=CAVSAt8T2xwt3pXCgFSk8B+zZMsPOLX9wb5jOKZLqS/V1JWUk1R/fy72gP8crUEynfY26igDi5ocGoxNzxC3DVJFQv7CfoAICHkdm8lLiwoapOT8rvfYax0tS/aI0kzqrpJ/tHm4BvWohc48b2netgWvKRvbE6/BA3F1+SUBr6M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QH8jpjUT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QH8jpjUT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BFF91F000E9; Wed, 24 Jun 2026 06:46:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782283591; bh=qTgdzMLMshCYVBpBD/xe8FOx9yUbqJSARpmgFJAB3Iw=; h=From:To:Cc:Subject:Date; b=QH8jpjUTlUoj1NgHALKWJgnSXsWAOV405Km6mouiSfvnrHjpogGiLvQckgjUzzMV1 j4xDAORKOg8Ax7AQCrkko2N2s/bMn8DhMPsYdheJI46ZgyO8yDnvLMktI89T+AvQUi ZG+WtmcAV9vYzXWzmQQJcaEwtLsmorS4L8Wl+jYwKBdBinu2GXEvVytYy3ZdpY3N8+ UC84oegyinVGyLoZfgYZcHPaIC7quSPDLsZbfNXKmOk9Sl4Y/b3cfgo6rLG1zvsTqz fsRYky47MJStPe79xeH/e18mT742U+Ohskw2BdnzMbjLEYR7QO0W1nkM9V2URzJDZb qj2hTmLswNzow== From: Yu Kuai To: Tejun Heo , Josef Bacik , Jens Axboe Cc: Zheng Qixing , Christoph Hellwig , Tang Yizhou , Nilay Shroff , Ming Lei , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] md/linear: add fault-tolerant mode for unraid-like setups Date: Wed, 24 Jun 2026 14:46:19 +0800 Message-ID: <20260624064625.1743650-1-yukuai@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Yu Kuai Add a module parameter 'fault_tolerant' that changes how md-linear handles disk failures. When enabled: - Disk failures are isolated instead of failing the entire array - I/O to failed disks returns -EIO while healthy disks continue - The array remains operational with reduced capacity - Failed disk count is tracked and shown in /proc/mdstat This enables unraid-like functionality where individual disk failures don't bring down the entire array, allowing continued access to data on healthy disks. The fault_tolerant parameter can be set at module load time or dynamically via /sys/module/md_linear/parameters/fault_tolerant. Signed-off-by: Yu Kuai --- drivers/md/md-linear.c | 63 ++++++++++++++++++++++++++++++++++++------ 1 file changed, 55 insertions(+), 8 deletions(-) diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c index 8d7b82c4a723..8afc6665cfde 100644 --- a/drivers/md/md-linear.c +++ b/drivers/md/md-linear.c @@ -2,6 +2,10 @@ /* * linear.c : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc * ZYNGIER or + * + * Fault-tolerant mode added for unraid-like setups. + * When fault_tolerant=1, disk failures are isolated - I/O to failed disks + * returns -EIO while healthy disks continue operating normally. */ #include @@ -21,9 +25,15 @@ struct linear_conf { sector_t array_sectors; /* a copy of mddev->raid_disks */ int raid_disks; + atomic_t failed_disks; /* count of failed disks */ struct dev_info disks[] __counted_by(raid_disks); }; +static bool fault_tolerant; +module_param(fault_tolerant, bool, 0644); +MODULE_PARM_DESC(fault_tolerant, + "Enable fault-tolerant mode: isolate disk failures instead of failing array (default: false)"); + /* * find which device holds a particular offset */ @@ -96,6 +106,8 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) if (!conf) return ERR_PTR(-ENOMEM); + atomic_set(&conf->failed_disks, 0); + /* * conf->raid_disks is copy of mddev->raid_disks. The reason to * keep a copy of mddev->raid_disks in struct linear_conf is, @@ -251,7 +263,8 @@ static bool linear_make_request(struct mddev *mddev, struct bio *bio) bio_sector < start_sector)) goto out_of_bounds; - if (unlikely(is_rdev_broken(tmp_dev->rdev))) { + if (unlikely(is_rdev_broken(tmp_dev->rdev) || + test_bit(Faulty, &tmp_dev->rdev->flags))) { md_error(mddev, tmp_dev->rdev); bio_io_error(bio); return true; @@ -296,16 +309,47 @@ static bool linear_make_request(struct mddev *mddev, struct bio *bio) static void linear_status(struct seq_file *seq, struct mddev *mddev) { + struct linear_conf *conf = mddev->private; + seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2); + if (fault_tolerant) { + int failed = atomic_read(&conf->failed_disks); + + seq_puts(seq, " fault-tolerant"); + if (failed) + seq_printf(seq, " [%d failed]", failed); + } } static void linear_error(struct mddev *mddev, struct md_rdev *rdev) { - if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) { - char *md_name = mdname(mddev); - - pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n", - md_name, rdev->bdev); + char *md_name = mdname(mddev); + + if (fault_tolerant) { + /* + * Fault-tolerant mode: isolate the failed disk instead of + * failing the entire array. I/O to this disk will return -EIO + * but other disks continue operating normally. + */ + if (!test_and_set_bit(Faulty, &rdev->flags)) { + struct linear_conf *conf = mddev->private; + + atomic_inc(&conf->failed_disks); + pr_warn("md/linear%s: Disk failure on %pg detected, isolating device (fault-tolerant mode).\n", + md_name, rdev->bdev); + pr_warn("md/linear%s: %d disk(s) now failed, array continues with reduced capacity.\n", + md_name, atomic_read(&conf->failed_disks)); + /* Notify userspace about the state change */ + sysfs_notify_dirent_safe(rdev->sysfs_state); + } + } else { + /* + * Standard mode: fail the entire array on any disk failure. + */ + if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) { + pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n", + md_name, rdev->bdev); + } } } @@ -344,7 +388,7 @@ static void linear_exit(void) module_init(linear_init); module_exit(linear_exit); MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)"); +MODULE_DESCRIPTION("Linear device concatenation personality for MD with optional fault-tolerant mode"); MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/ MODULE_ALIAS("md-linear"); MODULE_ALIAS("md-level--1"); -- 2.43.0