From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CEDB011CAF; Tue, 7 Jan 2025 17:24:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736270659; cv=none; b=so22KrkCHN0jjzFhJLWVW6uAmsOa5UqxJ8vo5kZOOogjqea+EpgfXG5b9VzjylhxEod3J0Ods2/9JMnEx9hwAQj92YSavu9KjVrRKyUoL4hE29OsnYDhn2XoRfu/XH7wByZqhDwvdcERVhX5E9LTIjEfyMcco6h+l3ai0LccmbU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736270659; c=relaxed/simple; bh=zAHjEo90s8AQe1Ukw3ETz+enBvik3LzwMi+KNu7Eth4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Vq2UHg8eKROGg0CyHOWmiIjAkwSwsuEw2fPiRjxMKMUYh0jtLuJzaIQ39QVZbX2uE+a8fN+KUfcyP99u7cDzbf64x1VagErlNfVAECA4dhAuRaocrhgu+rALJ/3u7y6aHkQk78CWdJHetMC/et6TPYyekVQV0HCujYaf3fPKNMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gZ6E3lbG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gZ6E3lbG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DF7DC4CED6; Tue, 7 Jan 2025 17:24:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736270658; bh=zAHjEo90s8AQe1Ukw3ETz+enBvik3LzwMi+KNu7Eth4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gZ6E3lbGr5uzAJNdK43Ms4NKmSsdNrraqsxgh0Wi2WeszOj65WlfOKWZKhT3ALWT6 nUiz8eyhkSIiSCOizVIAEAY/l5blST+xtwLSeMimAYkg3iCQxX726wLiumYkMwD6B1 AxaW/MKokZUv8sxku8QNG+Tnc/SOTemC9MHuxxj4BNE8CwmHRzyARm9j9Hivd0rlwh XjV8p+N5GMgg1UK9LYj9Gjdj4AVTTAk1PJZNQa9m/vgUuCTzoOOVMzcTD9hM+f7fKp wMv09S03QTSpc6sY/DFLV8wdaAvmGwi8/xHDvCQwYTEoh7uktWmTWDdVfH7jhvNmEZ tWtvGYb8M4Ung== Date: Tue, 7 Jan 2025 12:24:17 -0500 From: Mike Snitzer To: Yu Kuai Cc: song@kernel.org, yukuai3@huawei.com, thetanix@gmail.com, colyli@suse.de, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, dm-devel@lists.linux.dev, axboe@kernel.dk, linux-block@vger.kernel.org Subject: Re: [PATCH RFC md-6.14] md: reintroduce md-linear Message-ID: References: <20250102112841.1227111-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250102112841.1227111-1-yukuai1@huaweicloud.com> On Thu, Jan 02, 2025 at 07:28:41PM +0800, Yu Kuai wrote: > From: Yu Kuai > > THe md-linear is removed by commit 849d18e27be9 ("md: Remove deprecated > CONFIG_MD_LINEAR") because it has been marked as deprecated for a long > time. > > However, md-linear is used widely for underlying disks with different size, > sadly we didn't know this until now, and it's true useful to create > partitions and assemble multiple raid and then append one to the other. > > People have to use dm-linear in this case now, however, they will prefer > to minimize the number of involved modules. > > Signed-off-by: Yu Kuai I agree with reinstating md-linear. If/when we do remove md-linear (again) we first need a seamless upgrade/conversion option (e.g. mdadm updated to use dm-linear in the backend instead of md-linear). This patch's header should probably also have this Fixes tag (unclear if linux-stable would pick it up but it really is a regression given there was no upgrade path offered to md-linear users): Fixes: 849d18e27be9 md: Remove deprecated CONFIG_MD_LINEAR Acked-by: Mike Snitzer