kernel/linux.git/include/uapi/linux/raid, branch v6.19.11

md: allow configuring logical block size

2025-11-11T03:20:15+00:00

Previously, raid array used the maximum logical block size (LBS) of all member disks. Adding a larger LBS disk at runtime could unexpectedly increase RAID's LBS, risking corruption of existing partitions. This can be reproduced by: ``` # LBS of sd[de] is 512 bytes, sdf is 4096 bytes. mdadm -CRq /dev/md0 -l1 -n3 /dev/sd[de] missing --assume-clean # LBS is 512 cat /sys/block/md0/queue/logical_block_size # create partition md0p1 parted -s /dev/md0 mklabel gpt mkpart primary 1MiB 100% lsblk | grep md0p1 # LBS becomes 4096 after adding sdf mdadm --add -q /dev/md0 /dev/sdf cat /sys/block/md0/queue/logical_block_size # partition lost partprobe /dev/md0 lsblk | grep md0p1 ``` Simply restricting larger-LBS disks is inflexible. In some scenarios, only disks with 512 bytes LBS are available currently, but later, disks with 4KB LBS may be added to the array. Making LBS configurable is the best way to solve this scenario. After this patch, the raid will: - store LBS in disk metadata - add a read-write sysfs 'mdX/logical_block_size' Future mdadm should support setting LBS via metadata field during RAID creation and the new sysfs. Though the kernel allows runtime LBS changes, users should avoid modifying it after creating partitions or filesystems to prevent compatibility issues. Only 1.x metadata supports configurable LBS. 0.90 metadata inits all fields to default values at auto-detect. Supporting 0.90 would require more extensive changes and no such use case has been observed. Note that many RAID paths rely on PAGE_SIZE alignment, including for metadata I/O. A larger LBS than PAGE_SIZE will result in metadata read/write failures. So this config should be prevented. Link: https://lore.kernel.org/linux-raid/20251103125757.1405796-6-linan666@huaweicloud.com Signed-off-by: Li Nan Reviewed-by: Xiao Ni Signed-off-by: Yu Kuai

md: keep recovery_cp in mdp_superblock_s

2025-08-16T00:47:38+00:00

commit 907a99c314a5 ("md: rename recovery_cp to resync_offset") replaces recovery_cp with resync_offset in mdp_superblock_s which is in md_p.h. md_p.h is used in userspace too. So mdadm building fails because of this. This patch revert this change. Fixes: 907a99c314a5 ("md: rename recovery_cp to resync_offset") Signed-off-by: Xiao Ni Link: https://lore.kernel.org/linux-raid/20250815040028.18085-1-xni@redhat.com Signed-off-by: Yu Kuai

md: rename recovery_cp to resync_offset

2025-07-30T17:26:04+00:00

'recovery_cp' was used to represent the progress of sync, but its name contains recovery, which can cause confusion. Replaces 'recovery_cp' with 'resync_offset' for clarity. Signed-off-by: Li Nan Link: https://lore.kernel.org/linux-raid/20250722033340.1933388-1-linan666@huaweicloud.com Signed-off-by: Yu Kuai

md: reintroduce md-linear

2025-01-13T15:36:29+00:00

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. Fixes: 849d18e27be9 ("md: Remove deprecated CONFIG_MD_LINEAR") Cc: stable@vger.kernel.org Signed-off-by: Yu Kuai Acked-by: Coly Li Acked-by: Mike Snitzer Link: https://lore.kernel.org/r/20250102112841.1227111-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu

md: Remove deprecated CONFIG_MD_FAULTY

2023-12-19T18:37:50+00:00

md-faulty has been marked as deprecated for 2.5 years. Remove it. Cc: Christoph Hellwig Cc: Jens Axboe Cc: Neil Brown Cc: Guoqing Jiang Cc: Mateusz Grzonka Cc: Jes Sorensen Signed-off-by: Song Liu Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20231214222107.2016042-4-song@kernel.org

md: Remove deprecated CONFIG_MD_MULTIPATH

2023-12-19T18:37:41+00:00

md-multipath has been marked as deprecated for 2.5 years. Remove it. Cc: Christoph Hellwig Cc: Jens Axboe Cc: Neil Brown Cc: Guoqing Jiang Cc: Mateusz Grzonka Cc: Jes Sorensen Signed-off-by: Song Liu Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20231214222107.2016042-3-song@kernel.org

md: Remove deprecated CONFIG_MD_LINEAR

2023-12-19T18:16:51+00:00

md-linear has been marked as deprecated for 2.5 years. Remove it. Cc: Christoph Hellwig Cc: Jens Axboe Cc: Neil Brown Cc: Guoqing Jiang Cc: Mateusz Grzonka Cc: Jes Sorensen Signed-off-by: Song Liu Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20231214222107.2016042-2-song@kernel.org

treewide: uapi: Replace zero-length arrays with flexible-array members

2022-06-28T19:26:05+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. This code was transformed with the help of Coccinelle: (linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch) @@ identifier S, member, array; type T1, T2; @@ struct S { ... T1 member; T2 array[ - 0 ]; }; -fstrict-flex-arrays=3 is coming and we need to land these changes to prevent issues like these in the short future: ../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0, but the source string has length 2 (including NUL byte) [-Wfortify-source] strcpy(de3->name, "."); ^ Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If this breaks anything, we can use a union with a new member name. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78 Build-tested-by: kernel test robot Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/ Acked-by: Dan Williams # For ndctl.h Signed-off-by: Gustavo A. R. Silva

raid: md_p.h: drop duplicated word in a comment

2020-07-22T05:05:32+00:00

Drop the doubled word "the" in a comment. Signed-off-by: Randy Dunlap Cc: Song Liu Cc: linux-raid@vger.kernel.org Signed-off-by: Song Liu

md: add feature flag MD_FEATURE_RAID0_LAYOUT

2019-09-13T20:10:06+00:00

Due to a bug introduced in Linux 3.14 we cannot determine the correctly layout for a multi-zone RAID0 array - there are two possibilities. It is possible to tell the kernel which to chose using a module parameter, but this can be clumsy to use. It would be best if the choice were recorded in the metadata. So add a feature flag for this purpose. If it is set, then the 'layout' field of the superblock is used to determine which layout to use. If this flag is not set, then mddev->layout gets set to -1, which causes the module parameter to be required. Acked-by: Guoqing Jiang Signed-off-by: NeilBrown Signed-off-by: Song Liu