Re: [PATCH v3 01/21] md/raid5: round bitmap stripes with sector division
From: sashiko-bot@kernel.org
Date: 2026-07-28 09:03:08
Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider: New issues: - [Medium] The commit message references a non-existent function `raid5_bitmap_sector_map()`. Pre-existing issues: - [High] This problem wasn't introduced by this patch, but the logic for calculating the previous array layout's upper bound `prev_end` incorrectly rounds down instead of rounding up, truncating the bitmap update range during an array reshape. --
--- Patch [1]: [PATCH v3 01/21] md/raid5: round bitmap stripes with sector division ---commit a735680352819f937150899bfef4b4a4111690e0 Author: Yu Kuai [off-list ref] md/raid5: round bitmap stripes with sector division This commit fixes rounding logic when aligning the array range to full RAID5 stripe widths. It replaces the mask-based round_down() and round_up() logic with sector_div() based arithmetic to correctly handle stripe widths that are not powers of two. Link: https://lore.kernel.org/all/20260726185916.2223460-1-mykola@meshstor.io/ (local)
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
[Severity: Medium] Does the commit message reference a function that isn't included in this patch? The modifications appear to be applied directly inline within raid5_bitmap_sector(), rather than a new raid5_bitmap_sector_map() helper.
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diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 0c5c9fb0606ee..35910bc6683bf 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c@@ -5956,8 +5956,11 @@ 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);
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@@ -5975,8 +5978,10 @@ 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;
[Severity: High] This isn't a bug introduced by this patch, but does the division logic for prev_end truncate the tracked bitmap range during an array reshape? Because prev_end serves as an exclusive upper bound, mathematically rounding it down (which the previous round_down() logic also did) means that if an I/O write crosses a chunk boundary, it gets a remainder when divided by sectors_per_chunk. Since the remainder doesn't trigger an increment (like it now does for end), dirty sectors at the end of the I/O are not marked in the bitmap for the previous layout. If a crash occurs, these unmarked sectors wouldn't be resynced, which could lead to stale parity and silent data corruption. -- Sashiko AI review · https://sashiko.dev/#/patchset/cover.1785206690.git.yukuai@fygo.io?part=1