From: Yu Kuai <yukuai@fygo.io>
llbitmap reshape keeps one live bitmap and cannot safely make an
existing bitmap bit cover a smaller data range.
The llbitmap chunksize itself will not shrink when mddev->chunk_sectors
stays the same or grows. However, shrinking mddev->chunk_sectors shrinks
sectors_per_chunk used by raid5_bitmap_sector_map(). That can shrink the
effective data range covered by each bit across the old and new RAID5
geometry. Reject that reshape while llbitmap is active.
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
drivers/md/raid5.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ff4da82f78fe..55af1d1eec63 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -8497,10 +8497,13 @@ static int check_reshape(struct mddev *mddev)
}
if (!check_stripe_cache(mddev))
return -ENOSPC;
+ if (mddev->bitmap_id == ID_LLBITMAP &&
+ mddev->new_chunk_sectors < mddev->chunk_sectors)
+ return -EOPNOTSUPP;
if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
mddev->delta_disks > 0)
if (resize_chunks(conf,
conf->previous_raid_disks
+ max(0, mddev->delta_disks),
--
2.51.0