kernel/linux.git/drivers/md/md-linear.c, 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/md-linear: Enable atomic writes

2025-11-08T08:55:19+00:00

All the infrastructure has already been plumbed to support this for stacked devices, so just enable the request_queue limits features flag. A note about chunk sectors for linear arrays: While it is possible to set a chunk sectors param for building a linear array, this is for specifying the granularity at which data sectors from the device are used. It is not the same as a stripe size, like for RAID0. As such, it is not appropriate to set chunk_sectors request queue limit to the same value, as chunk_sectors request limit is a boundary for which requests cannot straddle. However, request_queue limit max_hw_sectors is set to chunk sectors, which almost has the same effect as setting chunk_sectors limit. Link: https://lore.kernel.org/linux-raid/20250903161052.3326176-1-john.g.garry@oracle.com Signed-off-by: John Garry Reviewed-by: Yu Kuai Signed-off-by: Yu Kuai

Merge tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2025-10-02T17:16:56+00:00

Pull block updates from Jens Axboe: - NVMe pull request via Keith: - FC target fixes (Daniel) - Authentication fixes and updates (Martin, Chris) - Admin controller handling (Kamaljit) - Target lockdep assertions (Max) - Keep-alive updates for discovery (Alastair) - Suspend quirk (Georg) - MD pull request via Yu: - Add support for a lockless bitmap. A key feature for the new bitmap are that the IO fastpath is lockless. If a user issues lots of write IO to the same bitmap bit in a short time, only the first write has additional overhead to update bitmap bit, no additional overhead for the following writes. By supporting only resync or recover written data, means in the case creating new array or replacing with a new disk, there is no need to do a full disk resync/recovery. - Switch ->getgeo() and ->bios_param() to using struct gendisk rather than struct block_device. - Rust block changes via Andreas. This series adds configuration via configfs and remote completion to the rnull driver. The series also includes a set of changes to the rust block device driver API: a few cleanup patches, and a few features supporting the rnull changes. The series removes the raw buffer formatting logic from `kernel::block` and improves the logic available in `kernel::string` to support the same use as the removed logic. - floppy arch cleanups - Reduce the number of dereferencing needed for ublk commands - Restrict supported sockets for nbd. Mostly done to eliminate a class of issues perpetually reported by syzbot, by using nonsensical socket setups. - A few s390 dasd block fixes - Fix a few issues around atomic writes - Improve DMA interation for integrity requests - Improve how iovecs are treated with regards to O_DIRECT aligment constraints. We used to require each segment to adhere to the constraints, now only the request as a whole needs to. - Clean up and improve p2p support, enabling use of p2p for metadata payloads - Improve locking of request lookup, using SRCU where appropriate - Use page references properly for brd, avoiding very long RCU sections - Fix ordering of recursively submitted IOs - Clean up and improve updating nr_requests for a live device - Various fixes and cleanups * tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (164 commits) s390/dasd: enforce dma_alignment to ensure proper buffer validation s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request ublk: remove redundant zone op check in ublk_setup_iod() nvme: Use non zero KATO for persistent discovery connections nvmet: add safety check for subsys lock nvme-core: use nvme_is_io_ctrl() for I/O controller check nvme-core: do ioccsz/iorcsz validation only for I/O controllers nvme-core: add method to check for an I/O controller blk-cgroup: fix possible deadlock while configuring policy blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path blk-mq: Fix more tag iteration function documentation selftests: ublk: fix behavior when fio is not installed ublk: don't access ublk_queue in ublk_unmap_io() ublk: pass ublk_io to __ublk_complete_rq() ublk: don't access ublk_queue in ublk_need_complete_req() ublk: don't access ublk_queue in ublk_check_commit_and_fetch() ublk: don't pass ublk_queue to ublk_fetch() ublk: don't access ublk_queue in ublk_config_io_buf() ublk: don't access ublk_queue in ublk_check_fetch_buf() ublk: pass q_id and tag to __ublk_check_and_get_req() ...

md: init queue_limits->max_hw_wzeroes_unmap_sectors parameter

2025-09-16T16:37:12+00:00

The parameter max_hw_wzeroes_unmap_sectors in queue_limits should be equal to max_write_zeroes_sectors if it is set to a non-zero value. However, the stacked md drivers call md_init_stacking_limits() to initialize this parameter to UINT_MAX but only adjust max_write_zeroes_sectors when setting limits. Therefore, this discrepancy triggers a value check failure in blk_validate_limits(). $ modprobe scsi_debug num_parts=2 dev_size_mb=8 lbprz=1 lbpws=1 $ mdadm --create /dev/md0 --level=0 --raid-device=2 /dev/sda1 /dev/sda2 mdadm: Defaulting to version 1.2 metadata mdadm: RUN_ARRAY failed: Invalid argument Fix this failure by explicitly setting max_hw_wzeroes_unmap_sectors to max_write_zeroes_sectors. Since the linear and raid0 drivers support write zeroes, so they can support unmap write zeroes operation if all of the backend devices support it. However, the raid1/10/5 drivers don't support write zeroes, so we have to set it to zero. Fixes: 0c40d7cb5ef3 ("block: introduce max_{hw|user}_wzeroes_unmap_sectors to queue limits") Reported-by: John Garry Closes: https://lore.kernel.org/linux-block/803a2183-a0bb-4b7a-92f1-afc5097630d2@oracle.com/ Signed-off-by: Zhang Yi Tested-by: John Garry Reviewed-by: Li Nan Reviewed-by: Martin K. Petersen Reviewed-by: Yu Kuai Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/linux-raid/20250910111107.3247530-2-yi.zhang@huaweicloud.com Signed-off-by: Yu Kuai

md/md-linear: convert to use bio_submit_split_bioset()

2025-09-10T11:23:46+00:00

Unify bio split code, prepare to fix reordered split IO. Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

md: fix mssing blktrace bio split events

2025-09-10T11:23:45+00:00

If bio is split by internal handling like chunksize or badblocks, the corresponding trace_block_split() is missing, resulting in blktrace inability to catch BIO split events and making it harder to analyze the BIO sequence. Cc: stable@vger.kernel.org Fixes: 4b1faf931650 ("block: Kill bio_pair_split()") Signed-off-by: Yu Kuai Reviewed-by: Damien Le Moal Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

md: switch personalities to use md_submodule_head

2025-03-04T16:27:20+00:00

Remove the global list 'pers_list', and switch to use md_submodule_head, which is managed by xarry. Prepare to unify registration and unregistration for all sub modules. Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-5-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai

md: Fix linear_set_limits()

2025-01-31T18:18:50+00:00

queue_limits_cancel_update() must only be called if queue_limits_start_update() is called first. Remove the queue_limits_cancel_update() call from linear_set_limits() because there is no corresponding queue_limits_start_update() call. This bug was discovered by annotating all mutex operations with clang thread-safety attributes and by building the kernel with clang and -Wthread-safety. Cc: Yu Kuai Cc: Coly Li Cc: Mike Snitzer Cc: Christoph Hellwig Fixes: 127186cfb184 ("md: reintroduce md-linear") Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250129225636.2667932-1-bvanassche@acm.org Signed-off-by: Song Liu

md/md-linear: Fix a NULL vs IS_ERR() bug in linear_add()

2025-01-16T17:31:25+00:00

The linear_conf() returns error pointers, it doesn't return NULL. Update the error checking to match. Fixes: 127186cfb184 ("md: reintroduce md-linear") Signed-off-by: Dan Carpenter Reviewed-by: Yu Kuai Link: https://lore.kernel.org/r/add654be-759f-4b2d-93ba-a3726dae380c@stanley.mountain Signed-off-by: Song Liu

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