diff options
| author | Yu Kuai <yukuai@fygo.io> | 2026-08-03 03:50:14 +0800 |
|---|---|---|
| committer | Yu Kuai <yukuai@fygo.io> | 2026-08-07 14:43:33 +0800 |
| commit | 17ea021ae74987d6064c8195c4922fa025753892 (patch) | |
| tree | 947d448d80f57375aa91628643e762705dbd5b6d | |
| parent | a41bb2ee1aca486853e84920565e50c15f86fa5d (diff) | |
md/raid5: round bitmap stripes with sector division
raid5_bitmap_sector_map() aligns the array range to full RAID5 stripe
widths before converting it to component sectors. That width is
chunk_sectors multiplied by the number of data disks, and it is not
always a power of two.
Reproduce with a 4-disk RAID5, 1024-sector chunks, and three data disks.
The full-stripe width is 3072 sectors. For a one-sector write at array
sector 3072, correct rounding gives array range [3072, 6144), which maps
to component range [1024, 2048). The old round_down()/round_up() logic
instead gives [1024, 4096), which maps to [0, 1024).
Use sector_div() based arithmetic so the rounded range is aligned to the
actual RAID5 stripe width.
The deterministic mapper test now reports the fixed component range as
[1024, 2048), while the old mask-based range was [0, 1024).
Fixes: 9c89f604476c ("md/raid5: implement pers->bitmap_sector()")
Reported-by: Mykola Marzhan <mykola@meshstor.io>
Link: https://lore.kernel.org/all/20260726185916.2223460-1-mykola@meshstor.io/
Tested-by: Mykola Marzhan <mykola@meshstor.io>
Link: https://patch.msgid.link/20260802195038.164272-6-yukuai@kernel.org
Signed-off-by: Yu Kuai <yukuai@fygo.io>
| -rw-r--r-- | drivers/md/raid5.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d128d238e1da..2cc2546a29ae 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6029,8 +6029,11 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset, sectors_per_chunk = conf->chunk_sectors * (conf->raid_disks - conf->max_degraded); - start = round_down(start, sectors_per_chunk); - end = round_up(end, sectors_per_chunk); + sector_div(start, sectors_per_chunk); + start *= sectors_per_chunk; + if (sector_div(end, sectors_per_chunk)) + end++; + end *= sectors_per_chunk; start = raid5_compute_sector(conf, start, 0, &dd_idx, NULL); end = raid5_compute_sector(conf, end, 0, &dd_idx, NULL); @@ -6048,8 +6051,10 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset, sectors_per_chunk = conf->prev_chunk_sectors * (conf->previous_raid_disks - conf->max_degraded); - prev_start = round_down(prev_start, sectors_per_chunk); - prev_end = round_down(prev_end, sectors_per_chunk); + sector_div(prev_start, sectors_per_chunk); + prev_start *= sectors_per_chunk; + sector_div(prev_end, sectors_per_chunk); + prev_end *= sectors_per_chunk; prev_start = raid5_compute_sector(conf, prev_start, 1, &dd_idx, NULL); prev_end = raid5_compute_sector(conf, prev_end, 1, &dd_idx, NULL); |