kernel/linux.git/drivers/md/raid5.h, branch v7.2-rc2

md/raid5: validate discard support at request time

2026-06-20T19:16:24+00:00

Raid5 used to disable discard limits when devices_handle_discard_safely was not set or when stacked member limits could not support a full-stripe discard. That hides discard from userspace before raid5 can decide whether a request can be handled safely. Follow other virtual drivers and advertise a UINT_MAX discard limit for the md device. Cache lower discard support in r5conf when setting queue limits, and reject unsupported discard bios before queuing stripe work. Link: https://patch.msgid.link/20260605072639.2434847-3-yukuai@kernel.org Signed-off-by: Yu Kuai

buffer: Remove b_end_io

2026-06-04T08:28:10+00:00

This shrinks buffer_head by 8 bytes, letting us pack more buffer heads per slab. With a Debian config, it shrinks from 104 bytes to 96 bytes which is 42 objects per 4KiB page rather than 39, a 7% reduction in the amount of memory used. Signed-off-by: Matthew Wilcox (Oracle) Link: https://patch.msgid.link/20260528173150.1093780-33-willy@infradead.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner (Amutable)

md/raid5: remove stale md_raid5_kick_device() declaration

2026-03-22T18:15:11+00:00

Remove the unused md_raid5_kick_device() declaration from raid5.h - no definition exists for this function. Signed-off-by: Chen Cheng Reviewed-by: Yu Kuai Link: https://lore.kernel.org/linux-raid/20260304110919.15071-1-chencheng@fnnas.com/ Signed-off-by: Yu Kuai

md: remove recovery_disabled

2026-01-26T05:17:38+00:00

'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 Signed-off-by: Yu Kuai

md/raid5: make sure max_sectors is not less than io_opt

2026-01-26T05:11:51+00:00

Otherwise, even if user issue IO by io_opt, such IO will be split by max_sectors before they are submitted to raid5. For consequence, full stripe IO is impossible. BTW, dm-raid5 is not affected and still have such problem. Link: https://lore.kernel.org/linux-raid/20260114171241.3043364-7-yukuai@fnnas.com Signed-off-by: Yu Kuai

md/raid5: use mempool to allocate stripe_request_ctx

2026-01-26T05:11:29+00:00

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 Reviewed-by: Li Nan

md/md-bitmap: move bitmap_{start, end}write to md upper layer

2025-01-13T16:56:11+00:00

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 Link: https://lore.kernel.org/r/20250109015145.158868-6-yukuai1@huaweicloud.com Signed-off-by: Song Liu

md/md-bitmap: remove the last parameter for bimtap_ops->endwrite()

2025-01-13T16:56:10+00:00

For the case that IO failed for one rdev, the bit will be mark as NEEDED in following cases: 1) If badblocks is set and rdev is not faulty; 2) If rdev is faulty; Case 1) is useless because synchronize data to badblocks make no sense. Case 2) can be replaced with mddev->degraded. Also remove R1BIO_Degraded, R10BIO_Degraded and STRIPE_DEGRADED since case 2) no longer use them. Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20250109015145.158868-3-yukuai1@huaweicloud.com Signed-off-by: Song Liu

md/raid5: Increase r5conf.cache_name size

2024-11-12T23:11:09+00:00

For compiling with W=1, the following warning can be seen: drivers/md/raid5.c: In function ‘setup_conf’: drivers/md/raid5.c:2423:12: error: ‘%s’ directive output may be truncated writing up to 31 bytes into a region of size between 16 and 26 [-Werror=format-truncation=] "raid%d-%s", conf->level, mdname(conf->mddev)); ^~ drivers/md/raid5.c:2422:3: note: ‘snprintf’ output between 7 and 48 bytes into a destination of size 32 snprintf(conf->cache_name[0], namelen, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "raid%d-%s", conf->level, mdname(conf->mddev)); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Increase the array size to avoid this warning. Signed-off-by: John Garry Link: https://lore.kernel.org/r/20241112161019.4154616-2-john.g.garry@oracle.com Signed-off-by: Song Liu

md/raid5: rename wait_for_overlap to wait_for_reshape

2024-08-29T16:37:10+00:00

The only remaining uses of wait_for_overlap are related to reshape so rename it accordingly. Signed-off-by: Artur Paszkiewicz Link: https://lore.kernel.org/r/20240827153536.6743-4-artur.paszkiewicz@intel.com Signed-off-by: Song Liu