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([2600:4040:5f58:2500:48a3:a7cd:313e:1c7a]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6dd181d5ac1sm183958916d6.120.2025.01.07.12.34.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Jan 2025 12:34:10 -0800 (PST) Message-ID: <13a377d4-f647-436a-806e-c05413cef837@gmail.com> Date: Tue, 7 Jan 2025 15:34:09 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC md-6.14] md: reintroduce md-linear To: Mike Snitzer , 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 References: <20250102112841.1227111-1-yukuai1@huaweicloud.com> Content-Language: en-US From: RIc Wheeler In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/7/25 12:24 PM, Mike Snitzer wrote: > 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). Agree with the need for an upgrade/conversion path. > > 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 >