On Thu, Jan 02, 2025 at 07:28:41PM +0800, Yu Kuai wrote: > From: Yu Kuai <yukuai3@xxxxxxxxxx> > > 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 <yukuai3@xxxxxxxxxx> 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 <snitzer@xxxxxxxxxx>