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path: root/drivers/md/md.h
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2026-08-07md: add exact bitmap mapping and reshape hooksYu Kuai1-0/+4
Add bitmap mapping and reshape hooks needed by llbitmap reshape support without teaching md core to account a single bio against multiple bitmap ranges. This also adds the old/new bitmap geometry helpers used by personalities to describe reshape mapping to llbitmap. Tested-by: Mykola Marzhan <mykola@meshstor.io> Link: https://patch.msgid.link/20260802195038.164272-13-yukuai@kernel.org Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-08-07md: add helper to split bios at reshape offsetYu Kuai1-0/+4
Add mddev_bio_split_at_reshape_offset() so personalities can share reshape-offset bio splitting instead of open-coding the same boundary handling in multiple places. The helper first applies the optional max_sectors limit. If reshape is running and the bio crosses reshape_position, it further limits the front bio to the current reshape boundary so callers can account and submit one side of the reshape at a time. Snapshot reshape_position with READ_ONCE(). RAID5 and RAID10 update this field as reshape progresses, while the I/O path only needs one consistent decision point for the current bio. Using an explicit single load avoids a plain lockless access and prevents the compiler from refetching a different boundary while deciding whether and where to split. When a split is needed, bio_submit_split_bioset() submits the remainder and returns the front bio. Callers must therefore continue processing the returned bio, not the original pointer. Tested-by: Mykola Marzhan <mykola@meshstor.io> Link: https://patch.msgid.link/20260802195038.164272-12-yukuai@kernel.org Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-07-31md: scope memalloc_noio to allocation critical sectionsChen Cheng1-1/+0
Storing a memalloc_noio_save() token in mddev->noio_flags lets one task save the token and another task restore it. With concurrent suspend sysfs writes, task A can enter PF_MEMALLOC_NOIO, return to userspace still in that scope, and later task B can restore A's saved token. Avoid tying the token lifetime to mddev. Keep mddev_suspend() and mddev_resume() only responsible for array suspension, and enter PF_MEMALLOC_NOIO only in the MD paths that allocate memory after the array has been suspended. Restore the token before resuming the array. A reproducer repeatedly writes suspend_lo and suspend_hi from concurrent workers and checks each worker's /proc/self/stat flags before and after the sysfs write. Link: https://github.com/chencheng-fnnas/reproducer/blob/main/repro-md-noio-token-leak.sh Fixes: 78f57ef9d50a ("md: use memalloc scope APIs in mddev_suspend()/mddev_resume()") Signed-off-by: Chen Cheng <chencheng@fnnas.com> Reviewed-by: Yu Kuai <yukuai@fygo.io> Link: https://patch.msgid.link/20260718084218.417895-1-chencheng@fnnas.com Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-07-31md: widen badblock sectors param from int to sector_tHiroshi Nishida1-3/+3
The badblocks core API -- badblocks_set(), badblocks_clear() and badblocks_check() -- and the is_badblock() helper all take the range length as sector_t. The md wrappers rdev_set_badblocks(), rdev_clear_badblocks() and rdev_has_badblock(), however, declared the same length as int, narrowing sector_t to int and back again in the middle of an otherwise 64-bit clean path. Change the sectors parameter to sector_t in these three wrappers so it matches the core API and is_badblock(). No functional change: current callers pass per-I/O or per-resync-chunk lengths well within int range. This just removes a gratuitous truncation point and keeps the type consistent end to end. Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com> Link: https://patch.msgid.link/20260710132329.7273-3-nishidafmly@gmail.com Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-05-31md/raid1,raid10: fix deadlock in read error recovery pathAbd-Alrhman Masalkhi1-0/+5
raid1d and raid10d may resubmit a split md cloned bio while handling a read error. In this case, resubmitting the bio can lead to a deadlock if the array is suspended before md_handle_request() acquires an active_io reference via percpu_ref_tryget_live(). Since the cloned bio already holds an active_io reference, trying to acquire another reference via percpu_ref_tryget_live() can lead to a deadlock while the array is suspended. Fix this by using percpu_ref_get() for md cloned bios. Fixes: bb2a9acefaf9 ("md/raid1: switch to use md_account_bio() for io accounting") Fixes: 820455238366 ("md/raid10: switch to use md_account_bio() for io accounting") Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> Reviewed-by: Xiao Ni <xiao@kernel.org> Reviewed-by: Yu Kuai <yukuai@fygo.io> Link: https://patch.msgid.link/20260501114652.590037-2-abd.masalkhi@gmail.com Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-05-31dm-raid: only requeue bios when dm is suspendingBenjamin Marzinski1-0/+2
Returning DM_MAPIO_REQUEUE from the target map() function only requeues the bio during noflush suspends. During regular operations or during flushing suspends, it fails the bio. Failing the bio during flushing suspends is the correct behavior here. The bio cannot be handled, and dm-raid cannot suspend while it is outstanding. But during normal operations, dm-raid should not push the bio back to dm. Instead, wait for the reshape to be resumed. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Reviewed-by: Xiao Ni <xiao@kernel.org> Link: https://patch.msgid.link/20260428232010.2785514-1-bmarzins@redhat.com Signed-off-by: Yu Kuai <yukuai@fygo.io>
2026-04-28md/md-bitmap: add a none backend for bitmap growYu Kuai1-0/+3
Add a real none bitmap backend that exposes the common bitmap sysfs group and use it to keep bitmap/location available when an array has no bitmap. Then switch the bitmap location sysfs path to move only between none and the classic bitmap backend, using the no-sysfs bitmap helpers while merging or unmerging the internal bitmap sysfs group. This restores mdadm --grow bitmap addition through bitmap/location. Fixes: fb8cc3b0d9db ("md/md-bitmap: delay registration of bitmap_ops until creating bitmap") Reviewed-by: Su Yue <glass.su@suse.com> Link: https://lore.kernel.org/r/20260425024615.1696892-4-yukuai@fnnas.com Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-04-28md: use mddev_lock_nointr() in mddev_suspend_and_lock_nointr()Abd-Alrhman Masalkhi1-1/+1
This keeps mddev locking consistent and ensures that any future changes to locking behavior are done through the wrapper. Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> Link: https://lore.kernel.org/r/20260415140319.376578-3-abd.masalkhi@gmail.com Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-04-28md/raid5: Fix UAF on IO across the reshape positionBenjamin Marzinski1-1/+0
If make_stripe_request() returns STRIPE_WAIT_RESHAPE, raid5_make_request() will free the cloned bio. But raid5_make_request() can call make_stripe_request() multiple times, writing to the various stripes. If that bio got added to the toread or towrite lists of a stripe disk in an earlier call to make_stripe_request(), then it's not safe to just free the bio if a later part of it is found to cross the reshape position. Doing so can lead to a UAF error, when bio_endio() is called on the bio for the earlier stripes. Instead, raid5_make_request() needs to wait until all parts of the bio have called bio_endio(). To do this, bios that cross the reshape position while the reshape can't make progress are flagged as needing to wait for all parts to complete. When raid5_make_request() has a bio that failed make_stripe_request() with STRIPE_WAIT_RESHAPE, it sets bi->bi_private to a completion struct and waits for completion after ending the bio. When the bio_endio() is called for the last time on a clone bio with bi->bi_private set, it wakes up the waiter. This guarantees that raid5_make_request() doesn't return until the cloned bio needing a retry for io across the reshape boundary is safely cleaned up. There is a simple reproducer available at [1]. Compile the kernel with KASAN for more useful reporting when the error is triggered (this is not necessary to see the bug). [1] https://gist.github.com/bmarzins/e48598824305cf2171289e47d7241fa5 Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Reviewed-by: Xiao Ni <xni@redhat.com> Link: https://lore.kernel.org/r/20260408043548.1695157-1-bmarzins@redhat.com Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-04-07md/raid1: serialize overlap io for writemostly diskXiao Ni1-1/+4
Previously, using wait_event() would wake up all waiters simultaneously, and they would compete for the tree lock. The bio which gets the lock first will be handled, so the write sequence cannot be guaranteed. For example: bio1(100,200) bio2(150,200) bio3(150,300) The write sequence of fast device is bio1,bio2,bio3. But the write sequence of slow device could be bio1,bio3,bio2 due to lock competition. This causes data corruption. Replace waitqueue with a fifo list to guarantee the write sequence. And it also needs to iterate the list when removing one entry. If not, it may miss the opportunity to wake up the waiting io. For example: bio1(1,3), bio2(2,4) bio3(5,7), bio4(6,8) These four bios are in the same bucket. bio1 and bio3 are inserted into the rbtree. bio2 and bio4 are added to the waiting list and bio2 is the first one. bio3 returns from slow disk and tries to wake up the waiting bios. bio2 is removed from the list and will be handled. But bio1 hasn't finished. So bio2 will be added into waiting list again. Then bio1 returns from slow disk and wakes up waiting bios. bio4 is removed from the list and will be handled. Now bio1, bio3 and bio4 all finish and bio2 is left on the waiting list. So it needs to iterate the waiting list to wake up the right bio. Signed-off-by: Xiao Ni <xni@redhat.com> Link: https://lore.kernel.org/linux-raid/20260324072501.59865-1-xni@redhat.com/ Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-02-02md: fix return value of mddev_trylockXiao Ni1-2/+2
A return value of 0 is treaded as successful lock acquisition. In fact, a return value of 1 means getting the lock successfully. Link: https://lore.kernel.org/linux-raid/20260127073951.17248-1-xni@redhat.com Fixes: 9e59d609763f ("md: call del_gendisk in control path") Reported-by: Bart Van Assche <bvanassche@acm.org> Closes: https://lore.kernel.org/linux-raid/20250611073108.25463-1-xni@redhat.com/T/#mfa369ef5faa4aa58e13e6d9fdb88aecd862b8f2f Signed-off-by: Xiao Ni <xni@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Li Nan <linan122@huawei.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-01-26md: remove recovery_disabledLi Nan1-6/+0
'recovery_disabled' logic is complex and confusing, originally intended to preserve raid in extreme scenarios. It was used in following cases: - When sync fails and setting badblocks also fails, kick out non-In_sync rdev and block spare rdev from joining to preserve raid [1] - When last backup is unavailable, prevent repeated add-remove of spares triggering recovery [2] The original issues are now resolved: - Error handlers in all raid types prevent last rdev from being kicked out - Disks with failed recovery are marked Faulty and can't re-join Therefore, remove 'recovery_disabled' as it's no longer needed. [1] 5389042ffa36 ("md: change managed of recovery_disabled.") [2] 4044ba58dd15 ("md: don't retry recovery of raid1 that fails due to error on source drive.") Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-13-linan666@huaweicloud.com Signed-off-by: Li Nan <linan122@huawei.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-01-26md: remove MD_RECOVERY_ERROR handling and simplify resync_offset updateLi Nan1-2/+0
Following previous patch "md: update curr_resync_completed even when MD_RECOVERY_INTR is set", 'curr_resync_completed' always equals 'curr_resync' for resync, so MD_RECOVERY_ERROR can be removed. Also, simplify resync_offset update logic. Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-8-linan666@huaweicloud.com Signed-off-by: Li Nan <linan122@huawei.com> Reviewed-by: Yu Kuai <yukuai@fnnas.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-01-26md: factor error handling out of md_done_sync into helperLi Nan1-1/+2
The 'ok' parameter in md_done_sync() is redundant for most callers that always pass 'true'. Factor error handling logic into a separate helper function md_sync_error() to eliminate unnecessary parameter passing and improve code clarity. No functional changes introduced. Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-3-linan666@huaweicloud.com Signed-off-by: Li Nan <linan122@huawei.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2026-01-26md/raid5: use mempool to allocate stripe_request_ctxYu Kuai1-0/+4
On the one hand, stripe_request_ctx is 72 bytes, and it's a bit huge for a stack variable. On the other hand, the bitmap sectors_to_do is a fixed size, result in max_hw_sector_kb of raid5 array is at most 256 * 4k = 1Mb, and this will make full stripe IO impossible for the array that chunk_size * data_disks is bigger. Allocate ctx during runtime will make it possible to get rid of this limit. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-6-yukuai@fnnas.com Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Li Nan <linan122@huawei.com>
2026-01-26md: merge mddev serialize_policy into mddev_flagsYu Kuai1-2/+2
There is not need to use a separate field in struct mddev, there are no functional changes. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-5-yukuai@fnnas.com Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Li Nan <linan122@huawei.com>
2026-01-26md: merge mddev faillast_dev into mddev_flagsYu Kuai1-1/+2
There is not need to use a separate field in struct mddev, there are no functional changes. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-4-yukuai@fnnas.com Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Li Nan <linan122@huawei.com>
2026-01-26md: merge mddev has_superblock into mddev_flagsYu Kuai1-1/+2
There is not need to use a separate field in struct mddev, there are no functional changes. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-3-yukuai@fnnas.com Signed-off-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Li Nan <linan122@huawei.com>
2025-11-11md: allow configuring logical block sizeLi Nan1-0/+1
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 <linan122@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2025-11-08md: avoid repeated calls to del_gendiskXiao Ni1-0/+1
There is a uaf problem which is found by case 23rdev-lifetime: Oops: general protection fault, probably for non-canonical address 0xdead000000000122 RIP: 0010:bdi_unregister+0x4b/0x170 Call Trace: <TASK> __del_gendisk+0x356/0x3e0 mddev_unlock+0x351/0x360 rdev_attr_store+0x217/0x280 kernfs_fop_write_iter+0x14a/0x210 vfs_write+0x29e/0x550 ksys_write+0x74/0xf0 do_syscall_64+0xbb/0x380 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff5250a177e The sequence is: 1. rdev remove path gets reconfig_mutex 2. rdev remove path release reconfig_mutex in mddev_unlock 3. md stop calls do_md_stop and sets MD_DELETED 4. rdev remove path calls del_gendisk because MD_DELETED is set 5. md stop path release reconfig_mutex and calls del_gendisk again So there is a race condition we should resolve. This patch adds a flag MD_DO_DELETE to avoid the race condition. Link: https://lore.kernel.org/linux-raid/20251029063419.21700-1-xni@redhat.com Fixes: 9e59d609763f ("md: call del_gendisk in control path") Signed-off-by: Xiao Ni <xni@redhat.com> Suggested-by: Yu Kuai <yukuai@fnnas.com> Reviewed-by: Li Nan <linan122@huawei.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2025-11-08md: fix rcu protection in md_wakeup_threadYun Zhou1-1/+7
We attempted to use RCU to protect the pointer 'thread', but directly passed the value when calling md_wakeup_thread(). This means that the RCU pointer has been acquired before rcu_read_lock(), which renders rcu_read_lock() ineffective and could lead to a use-after-free. Link: https://lore.kernel.org/linux-raid/20251015083227.1079009-1-yun.zhou@windriver.com Fixes: 446931543982 ("md: protect md_thread with rcu") Signed-off-by: Yun Zhou <yun.zhou@windriver.com> Reviewed-by: Li Nan <linan122@huawei.com> Reviewed-by: Yu Kuai <yukuai@fnnas.com> Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2025-09-06md/md-llbitmap: introduce new lockless bitmapYu Kuai1-2/+2
Redundant data is used to enhance data fault tolerance, and the storage method for redundant data vary depending on the RAID levels. And it's important to maintain the consistency of redundant data. Bitmap is used to record which data blocks have been synchronized and which ones need to be resynchronized or recovered. Each bit in the bitmap represents a segment of data in the array. When a bit is set, it indicates that the multiple redundant copies of that data segment may not be consistent. Data synchronization can be performed based on the bitmap after power failure or readding a disk. If there is no bitmap, a full disk synchronization is required. Due to known performance issues with md-bitmap and the unreasonable implementations: - self-managed IO submitting like filemap_write_page(); - global spin_lock I have decided not to continue optimizing based on the current bitmap implementation, this new bitmap is invented without locking from IO fast path and can be used with fast disks. For designs and details, see the comments in drivers/md-llbitmap.c. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-12-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06md: add a new recovery_flag MD_RECOVERY_LAZY_RECOVERYu Kuai1-0/+2
This flag is used by llbitmap in later patches to skip raid456 initial recover and delay building initial xor data to first write. https://lore.kernel.org/linux-raid/20250829080426.1441678-10-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2025-09-06md: add a new mddev field 'bitmap_id'Yu Kuai1-0/+2
Prepare to store the bitmap id selected by user, also refactor mddev_set_bitmap_ops a bit in case the value is invalid. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-5-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Li Nan <linan122@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-09-06md/md-bitmap: support discard for bitmap opsYu Kuai1-0/+1
Use two new methods {start, end}_discard in bitmap_ops and a new field 'rw' in struct md_io_clone to handle discard IO, prepare to support new md bitmap. Since all bitmap functions to hanlde write IO are the same, also add typedef to make code cleaner. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-4-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06md: factor out a helper raid_is_456()Yu Kuai1-0/+6
There are no functional changes, the helper will be used by llbitmap in following patches. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-3-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06md: add a new parameter 'offset' to md_super_write()Yu Kuai1-2/+3
The parameter is always set to 0 for now, following patches will use this helper to write llbitmap to underlying disks, allow writing dirty sectors instead of the whole page. Also rename md_super_write to md_write_metadata since there is nothing super-block specific. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-2-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Li Nan <linan122@huawei.com>
2025-09-06md/md-bitmap: introduce CONFIG_MD_BITMAPYu Kuai1-2/+1
Now that all implementations are internal, it's sensible to add a config option for md-bitmap, and it's a good way for isolation. Link: https://lore.kernel.org/linux-raid/20250707012711.376844-16-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-09-06md/md-bitmap: merge md_bitmap_group into bitmap_operationsYu Kuai1-1/+0
Now that all bitmap implementations are internal, it doesn't make sense to export md_bitmap_group anymore. Link: https://lore.kernel.org/linux-raid/20250707012711.376844-5-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-07-31md: rename recovery_cp to resync_offsetLi Nan1-1/+1
'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 <linan122@huawei.com> Link: https://lore.kernel.org/linux-raid/20250722033340.1933388-1-linan666@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2025-07-12md: call del_gendisk in control pathXiao Ni1-2/+24
Now del_gendisk and put_disk are called asynchronously in workqueue work. The asynchronous way has a problem that the device node can still exist after mdadm --stop command returns in a short window. So udev rule can open this device node and create the struct mddev in kernel again. So put del_gendisk in control path and still leave put_disk in md_kobj_release to avoid uaf of gendisk. Function del_gendisk can't be called with reconfig_mutex. If it's called with reconfig mutex, a deadlock can happen. del_gendisk waits all sysfs files access to finish and sysfs file access waits reconfig mutex. So put del_gendisk after releasing reconfig mutex. But there is still a window that sysfs can be accessed between mddev_unlock and del_gendisk. So some actions (add disk, change level, .e.g) can happen which lead unexpected results. MD_DELETED is used to resolve this problem. MD_DELETED is set before releasing reconfig mutex and it should be checked for these sysfs access which need reconfig mutex. For sysfs access which don't need reconfig mutex, del_gendisk will wait them to finish. But it doesn't need to do this in function mddev_lock_nointr. There are ten places that call it. * Five of them are in dm raid which we don't need to care. MD_DELETED is only used for md raid. * stop_sync_thread, md_do_sync and md_start_sync are related sync request, and it needs to wait sync thread to finish before stopping an array. * md_ioctl: md_open is called before md_ioctl, so ->openers is added. It will fail to stop the array. So it doesn't need to check MD_DELETED here * md_set_readonly: It needs to call mddev_set_closing_and_sync_blockdev when setting readonly or read_auto. So it will fail to stop the array too because MD_CLOSING is already set. Reviewed-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Xiao Ni <xni@redhat.com> Link: https://lore.kernel.org/linux-raid/20250611073108.25463-2-xni@redhat.com Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2025-05-10md: clean up accounting for issued sync IOYu Kuai1-11/+0
It's no longer used and can be removed, also remove the field 'gendisk->sync_io'. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-10-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-05-10md: fix is_mddev_idle()Yu Kuai1-1/+2
If sync_speed is above speed_min, then is_mddev_idle() will be called for each sync IO to check if the array is idle, and inflight sync_io will be limited if the array is not idle. However, while mkfs.ext4 for a large raid5 array while recovery is in progress, it's found that sync_speed is already above speed_min while lots of stripes are used for sync IO, causing long delay for mkfs.ext4. Root cause is the following checking from is_mddev_idle(): t1: submit sync IO: events1 = completed IO - issued sync IO t2: submit next sync IO: events2 = completed IO - issued sync IO if (events2 - events1 > 64) For consequence, the more sync IO issued, the less likely checking will pass. And when completed normal IO is more than issued sync IO, the condition will finally pass and is_mddev_idle() will return false, however, last_events will be updated hence is_mddev_idle() can only return false once in a while. Fix this problem by changing the checking as following: 1) mddev doesn't have normal IO completed; 2) mddev doesn't have normal IO inflight; 3) if any member disks is partition, and all other partitions doesn't have IO completed. Also change rdev->last_events to unsigned long to cleanup type casting. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-9-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-05-10md: add a new api sync_io_depthYu Kuai1-0/+1
Currently if sync speed is above speed_min and below speed_max, md_do_sync() will wait for all sync IOs to be done before issuing new sync IO, means sync IO depth is limited to just 1. This limit is too low, in order to prevent sync speed drop conspicuously after fixing is_mddev_idle() in the next patch, add a new api for limiting sync IO depth, the default value is 32. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-8-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-05-10md: record dm-raid gendisk in mddevYu Kuai1-1/+2
Following patch will use gendisk to check if there are normal IO completed or inflight, to fix a problem in mdraid that foreground IO can be starved by background sync IO in later patches. Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-7-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com>
2025-03-13Merge tag 'md-6.15-20250312' of ↵Jens Axboe1-14/+34
https://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux into for-6.15/block Merge MD changes from Yu: "- fix recovery can preempt resync (Li Nan) - fix md-bitmap IO limit (Su Yue) - fix raid10 discard with REQ_NOWAIT (Xiao Ni) - fix raid1 memory leak (Zheng Qixing) - fix mddev uaf (Yu Kuai) - fix raid1,raid10 IO flags (Yu Kuai) - some refactor and cleanup (Yu Kuai)" * tag 'md-6.15-20250312' of https://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux: md/raid10: wait barrier before returning discard request with REQ_NOWAIT md/md-bitmap: fix wrong bitmap_limit for clustermd when write sb md/raid1,raid10: don't ignore IO flags md/raid5: merge reshape_progress checking inside get_reshape_loc() md: fix mddev uaf while iterating all_mddevs list md: switch md-cluster to use md_submodle_head md: don't export md_cluster_ops md/md-cluster: cleanup md_cluster_ops reference md: switch personalities to use md_submodule_head md: introduce struct md_submodule_head and APIs md: only include md-cluster.h if necessary md: merge common code into find_pers() md/raid1: fix memory leak in raid1_run() if no active rdev md: ensure resync is prioritized over recovery
2025-03-06badblocks: use sector_t instead of int to avoid truncation of badblocks lengthZheng Qixing1-3/+3
There is a truncation of badblocks length issue when set badblocks as follow: echo "2055 4294967299" > bad_blocks cat bad_blocks 2055 3 Change 'sectors' argument type from 'int' to 'sector_t'. This change avoids truncation of badblocks length for large sectors by replacing 'int' with 'sector_t' (u64), enabling proper handling of larger disk sizes and ensuring compatibility with 64-bit sector addressing. Fixes: 9e0e252a048b ("badblocks: Add core badblock management code") Signed-off-by: Zheng Qixing <zhengqixing@huawei.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Coly Li <colyli@kernel.org> Link: https://lore.kernel.org/r/20250227075507.151331-13-zhengqixing@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-06md: improve return types of badblocks handling functionsZheng Qixing1-4/+4
rdev_set_badblocks() only indicates success/failure, so convert its return type from int to boolean for better semantic clarity. rdev_clear_badblocks() return value is never used by any caller, convert it to void. This removes unnecessary value returns. Also update narrow_write_error() in both raid1 and raid10 to use boolean return type to match rdev_set_badblocks(). Signed-off-by: Zheng Qixing <zhengqixing@huawei.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20250227075507.151331-12-zhengqixing@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-05md: switch md-cluster to use md_submodle_headYu Kuai1-1/+1
To make code cleaner, and prepare to add kconfig for bitmap. Also remove the unsed global variables pers_lock, md_cluster_ops and md_cluster_mod, and exported symbols register_md_cluster_operations(), unregister_md_cluster_operations() and md_cluster_ops. Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-8-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Su Yue <glass.su@suse.com>
2025-03-05md: don't export md_cluster_opsYu Kuai1-1/+2
Add a new field 'cluster_ops' and initialize it md_setup_cluster(), so that the gloable variable 'md_cluter_ops' doesn't need to be exported. Also prepare to switch md-cluster to use md_submod_head. Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-7-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Su Yue <glass.su@suse.com>
2025-03-05md: switch personalities to use md_submodule_headYu Kuai1-6/+1
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 <yukuai3@huawei.com>
2025-03-05md: introduce struct md_submodule_head and APIsYu Kuai1-0/+31
Prepare to unify registration and unregistration of md personalities and md-cluster, also prepare for add kconfig for md-bitmap. Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-4-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2025-03-05md: only include md-cluster.h if necessaryYu Kuai1-7/+0
md-cluster is only supportted by raid1 and raid10, there is no need to include md-cluster.h for other personalities. Also move APIs that is only used in md-cluster.c from md.h to md-cluster.h. Link: https://lore.kernel.org/linux-raid/20250215092225.2427977-3-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Su Yue <glass.su@suse.com>
2025-01-13md/md-bitmap: move bitmap_{start, end}write to md upper layerYu Kuai1-0/+2
There are two BUG reports that raid5 will hang at bitmap_startwrite([1],[2]), root cause is that bitmap start write and end write is unbalanced, it's not quite clear where, and while reviewing raid5 code, it's found that bitmap operations can be optimized. For example, for a 4 disks raid5, with chunksize=8k, if user issue a IO (0 + 48k) to the array: ┌────────────────────────────────────────────────────────────┐ │chunk 0 │ │ ┌────────────┬─────────────┬─────────────┬────────────┼ │ sh0 │A0: 0 + 4k │A1: 8k + 4k │A2: 16k + 4k │A3: P │ │ ┼────────────┼─────────────┼─────────────┼────────────┼ │ sh1 │B0: 4k + 4k │B1: 12k + 4k │B2: 20k + 4k │B3: P │ ┼──────┴────────────┴─────────────┴─────────────┴────────────┼ │chunk 1 │ │ ┌────────────┬─────────────┬─────────────┬────────────┤ │ sh2 │C0: 24k + 4k│C1: 32k + 4k │C2: P │C3: 40k + 4k│ │ ┼────────────┼─────────────┼─────────────┼────────────┼ │ sh3 │D0: 28k + 4k│D1: 36k + 4k │D2: P │D3: 44k + 4k│ └──────┴────────────┴─────────────┴─────────────┴────────────┘ Before this patch, 4 stripe head will be used, and each sh will attach bio for 3 disks, and each attached bio will trigger bitmap_startwrite() once, which means total 12 times. - 3 times (0 + 4k), for (A0, A1 and A2) - 3 times (4 + 4k), for (B0, B1 and B2) - 3 times (8 + 4k), for (C0, C1 and C3) - 3 times (12 + 4k), for (D0, D1 and D3) After this patch, md upper layer will calculate that IO range (0 + 48k) is corresponding to the bitmap (0 + 16k), and call bitmap_startwrite() just once. Noted that this patch will align bitmap ranges to the chunks, for example, if user issue a IO (0 + 4k) to array: - Before this patch, 1 time (0 + 4k), for A0; - After this patch, 1 time (0 + 8k) for chunk 0; Usually, one bitmap bit will represent more than one disk chunk, and this doesn't have any difference. And even if user really created a array that one chunk contain multiple bits, the overhead is that more data will be recovered after power failure. Also remove STRIPE_BITMAP_PENDING since it's not used anymore. [1] https://lore.kernel.org/all/CAJpMwyjmHQLvm6zg1cmQErttNNQPDAAXPKM3xgTjMhbfts986Q@mail.gmail.com/ [2] https://lore.kernel.org/all/ADF7D720-5764-4AF3-B68E-1845988737AA@flyingcircus.io/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20250109015145.158868-6-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
2025-01-13md: add a new callback pers->bitmap_sector()Yu Kuai1-0/+3
This callback will be used in raid5 to convert io ranges from array to bitmap. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Xiao Ni <xni@redhat.com> Link: https://lore.kernel.org/r/20250109015145.158868-4-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
2024-11-05md: add a new helper rdev_blocked()Yu Kuai1-0/+24
The helper will be used in later patches for raid1/raid10/raid5, the difference is that Faulty rdev with unacknowledged bad block will not be considered blocked. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Tested-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com> Link: https://lore.kernel.org/r/20241031033114.3845582-2-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
2024-08-28Merge branch 'md-6.12-bitmap' into md-6.12Song Liu1-1/+2
From Yu Kuai (with minor changes by Song Liu): The background is that currently bitmap is using a global spin_lock, causing lock contention and huge IO performance degradation for all raid levels. However, it's impossible to implement a new lock free bitmap with current situation that md-bitmap exposes the internal implementation with lots of exported apis. Hence bitmap_operations is invented, to describe bitmap core implementation, and a new bitmap can be introduced with a new bitmap_operations, we only need to switch to the new one during initialization. And with this we can build bitmap as kernel module, but that's not our concern for now. This version was tested with mdadm tests and lvm2 tests. This set does not introduce new errors in these tests. * md-6.12-bitmap: (42 commits) md/md-bitmap: make in memory structure internal md/md-bitmap: merge md_bitmap_enabled() into bitmap_operations md/md-bitmap: merge md_bitmap_wait_behind_writes() into bitmap_operations md/md-bitmap: merge md_bitmap_free() into bitmap_operations md/md-bitmap: merge md_bitmap_set_pages() into struct bitmap_operations md/md-bitmap: merge md_bitmap_copy_from_slot() into struct bitmap_operation. md/md-bitmap: merge get_bitmap_from_slot() into bitmap_operations md/md-bitmap: merge md_bitmap_resize() into bitmap_operations md/md-bitmap: pass in mddev directly for md_bitmap_resize() md/md-bitmap: merge md_bitmap_daemon_work() into bitmap_operations md/md-bitmap: merge bitmap_unplug() into bitmap_operations md/md-bitmap: merge md_bitmap_unplug_async() into md_bitmap_unplug() md/md-bitmap: merge md_bitmap_sync_with_cluster() into bitmap_operations md/md-bitmap: merge md_bitmap_cond_end_sync() into bitmap_operations md/md-bitmap: merge md_bitmap_close_sync() into bitmap_operations md/md-bitmap: merge md_bitmap_end_sync() into bitmap_operations md/md-bitmap: remove the parameter 'aborted' for md_bitmap_end_sync() md/md-bitmap: merge md_bitmap_start_sync() into bitmap_operations md/md-bitmap: merge md_bitmap_endwrite() into bitmap_operations md/md-bitmap: merge md_bitmap_startwrite() into bitmap_operations ... Signed-off-by: Song Liu <song@kernel.org>
2024-08-27md: Remove flush handlingYu Kuai1-10/+0
For flush request, md has a special flush handling to merge concurrent flush request into single one, however, the whole mechanism is based on a disk level spin_lock 'mddev->lock'. And fsync can be called quite often in some user cases, for consequence, spin lock from IO fast path can cause performance degradation. Fortunately, the block layer already has flush handling to merge concurrent flush request, and it only acquires hctx level spin lock. (see details in blk-flush.c) This patch removes the flush handling in md, and converts to use general block layer flush handling in underlying disks. Flush test for 4 nvme raid10: start 128 threads to do fsync 100000 times, on arm64, see how long it takes. Test script: void* thread_func(void* arg) { int fd = *(int*)arg; for (int i = 0; i < FSYNC_COUNT; i++) { fsync(fd); } return NULL; } int main() { int fd = open("/dev/md0", O_RDWR); if (fd < 0) { perror("open"); exit(1); } pthread_t threads[THREADS]; struct timeval start, end; gettimeofday(&start, NULL); for (int i = 0; i < THREADS; i++) { pthread_create(&threads[i], NULL, thread_func, &fd); } for (int i = 0; i < THREADS; i++) { pthread_join(threads[i], NULL); } gettimeofday(&end, NULL); close(fd); long long elapsed = (end.tv_sec - start.tv_sec) * 1000000LL + (end.tv_usec - start.tv_usec); printf("Elapsed time: %lld microseconds\n", elapsed); return 0; } Test result: about 10 times faster: Before this patch: 50943374 microseconds After this patch: 5096347 microseconds Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20240827110616.3860190-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
2024-08-27md/md-bitmap: make in memory structure internalYu Kuai1-1/+1
Now that struct bitmap_page and bitmap is not used externally anymore, move them from md-bitmap.h to md-bitmap.c (expect that dm-raid is still using define marco 'COUNTER_MAX'). Also fix some checkpatch warnings. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20240826074452.1490072-43-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
2024-08-27md/md-bitmap: introduce struct bitmap_operationsYu Kuai1-0/+1
The structure is empty for now, and will be used in later patches to merge in bitmap operations, so that bitmap implementation won't be exposed. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20240826074452.1490072-12-yukuai1@huaweicloud.com Signed-off-by: Song Liu <song@kernel.org>
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