From ecb66a97af620135f207cddabeb7f589510640fc Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Mon, 3 Aug 2026 03:50:32 +0800 Subject: [PATCH] md/raid10: reject llbitmap reshape when md chunk shrinks 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 can shrink the effective data range covered by each bit for the RAID10 reshape geometry. Reject that reshape while llbitmap is active. Tested-by: Mykola Marzhan Link: https://patch.msgid.link/20260802195038.164272-24-yukuai@kernel.org Signed-off-by: Yu Kuai --- drivers/md/raid10.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index ed3c6fbe65f7..1c3393467667 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -4245,6 +4245,10 @@ static int raid10_check_reshape(struct mddev *mddev) if (conf->geo.far_copies != 1 && !conf->geo.far_offset) return -EINVAL; + if (mddev->bitmap_id == ID_LLBITMAP && + mddev->new_chunk_sectors && + mddev->new_chunk_sectors < mddev->chunk_sectors) + return -EOPNOTSUPP; if (setup_geo(&geo, mddev, geo_start) != conf->copies) /* mustn't change number of copies */