From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.synology.com (mail.synology.com [211.23.38.101]) (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 647F840DFDB; Thu, 9 Apr 2026 05:22:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=211.23.38.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775712159; cv=none; b=LwSF+AppnJ4fDfQyU/MJjjf39yfRkTYitELcOIGs8wCNLI9X+tWPUy6vP7E2/GPd2Fo+evmA7sW5QfU/JfNDcen1qS8oy0F3o6zUpF4u9dfT3LHjK9gdllF45cpn9UevI22RwI7mfb43wghzv9waDAnCz7g7WaCOs/+dqKGTfww= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775712159; c=relaxed/simple; bh=FIPJ0NEyBEc26V5aLXrqhdsiTTV4Z0yy5R0CZ1LAy2o=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=tw7Qss5RwPPC6UmxYYdGqfJUj1gJ3fN/3GZyPKAfyBcRZlLpvZLbNpwaoF/QFd6EfdYEvtgnWEeB3YWz25AtvTrkvc76ZXzZYA1Ek9SQcPckYFeTOZyiPFcfdxTE++NXAz1F1AKALwLC4FFMJXKtoejnCcqD4AHDvs9iB/XJvK8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=synology.com; spf=pass smtp.mailfrom=synology.com; dkim=pass (1024-bit key) header.d=synology.com header.i=@synology.com header.b=DPfx7pZa; arc=none smtp.client-ip=211.23.38.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=synology.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=synology.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=synology.com header.i=@synology.com header.b="DPfx7pZa" Received: from localhost.localdomain (unknown [10.17.211.152]) (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 mail.synology.com (Postfix) with ESMTPSA id 4frpGZ0qJRzHqtbtR; Thu, 9 Apr 2026 13:22:30 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synology.com; s=123; t=1775712150; bh=FIPJ0NEyBEc26V5aLXrqhdsiTTV4Z0yy5R0CZ1LAy2o=; h=From:To:Cc:Subject:Date; b=DPfx7pZaKHKJF4NeVyWx2wFthtLQXaool6A787Cpge/gUJDAWx8YKY8qq7qBQSfas +GcpVd9Z5SYqKkJjgQoz/gvJAEUmEXsioWiRm+xSPHczDcm8RR4P205Xi0keZKxxqk I8x+8F5lfIwhf7K+mImr9ufc5iR+cPtOR0kXcQbM= From: FengWei Shih To: song@kernel.org, yukuai@fnnas.com Cc: linan122@huawei.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, FengWei Shih Subject: [PATCH] md/raid5: fix race between reshape and chunk-aligned read Date: Thu, 9 Apr 2026 13:17:22 +0800 Message-Id: <20260409051722.2865321-1-dannyshih@synology.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Synology-Spam-Flag: no X-Synology-Virus-Status: no X-Synology-MCP-Status: no X-Synology-Spam-Status: score=0, required 6, WHITELIST_FROM_ADDRESS 0 Content-Type: text/plain raid5_make_request() checks mddev->reshape_position to decide whether to allow chunk-aligned reads. However in raid5_start_reshape(), the layout configuration (raid_disks, algorithm, etc.) is updated before mddev->reshape_position is set: reshape (raid5_start_reshape) read (raid5_make_request) ============================== =========================== write_seqcount_begin update raid_disks, algorithm... set conf->reshape_progress write_seqcount_end check mddev->reshape_position * still MaxSector, allow raid5_read_one_chunk() * use new layout raid5_quiesce() set mddev->reshape_position Since reshape_position is not yet updated, raid5_make_request() considers no reshape is in progress and proceeds with the chunk-aligned path, but the layout has already changed, causing raid5_compute_sector() to return an incorrect physical address. Fix this by reading conf->reshape_progress under gen_lock in raid5_read_one_chunk() and falling back to the stripe path if a reshape is in progress. Signed-off-by: FengWei Shih --- drivers/md/raid5.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index a8e8d431071b..bded2b86f0ef 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5421,6 +5421,11 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) sector_t sector, end_sector; int dd_idx; bool did_inc; + int seq; + + seq = read_seqcount_begin(&conf->gen_lock); + if (unlikely(conf->reshape_progress != MaxSector)) + return 0; if (!in_chunk_boundary(mddev, raid_bio)) { pr_debug("%s: non aligned\n", __func__); @@ -5431,6 +5436,9 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) &dd_idx, NULL); end_sector = sector + bio_sectors(raid_bio); + if (read_seqcount_retry(&conf->gen_lock, seq)) + return 0; + if (r5c_big_stripe_cached(conf, sector)) return 0; -- 2.25.1 Disclaimer: The contents of this e-mail message and any attachments are confidential and are intended solely for addressee. 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