[PATCH v2 md-6.14 4/5] md/raid5: implement pers->bitmap_sector()

[yukuai@kernel.org]

From: Yu Kuai <yukuai3@huawei.com>

Bitmap is used for the whole array for raid1/raid10, hence IO for the
array can be used directly for bitmap. However, bitmap is used for
underlying disks for raid5, hence IO for the array can't be used
directly for bitmap.

Implement pers->bitmap_sector() for raid5 to convert IO ranges from the
array to the underlying disks.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Yu Kuai <yukuai@kernel.org>
---
 drivers/md/raid5.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 6eb2841ce28c..b2fe201b599d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2950,6 +2950,23 @@ static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
 	r5c_update_on_rdev_error(mddev, rdev);
 }
 
+static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset,
+				unsigned long *sectors)
+{
+	struct r5conf *conf = mddev->private;
+	int sectors_per_chunk = conf->chunk_sectors * (conf->raid_disks -
+						       conf->max_degraded);
+	sector_t start = *offset;
+	sector_t end = start + *sectors;
+	int dd_idx;
+
+	start = round_down(start, sectors_per_chunk);
+	end = round_up(end, sectors_per_chunk);
+
+	*offset = raid5_compute_sector(conf, start, 0, &dd_idx, NULL);
+	*sectors = raid5_compute_sector(conf, end, 0, &dd_idx, NULL) - *offset;
+}
+
 /*
  * Input: a 'big' sector number,
  * Output: index of the data and parity disk, and the sector # in them.
@@ -8972,6 +8989,7 @@ static struct md_personality raid6_personality =
 	.takeover	= raid6_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,
 	.prepare_suspend = raid5_prepare_suspend,
+	.bitmap_sector	= raid5_bitmap_sector,
 };
 static struct md_personality raid5_personality =
 {
@@ -8997,6 +9015,7 @@ static struct md_personality raid5_personality =
 	.takeover	= raid5_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,
 	.prepare_suspend = raid5_prepare_suspend,
+	.bitmap_sector	= raid5_bitmap_sector,
 };
 
 static struct md_personality raid4_personality =
@@ -9023,6 +9042,7 @@ static struct md_personality raid4_personality =
 	.takeover	= raid4_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,
 	.prepare_suspend = raid5_prepare_suspend,
+	.bitmap_sector	= raid5_bitmap_sector,
 };
 
 static int __init raid5_init(void)
-- 
2.43.0