[PATCH] md: add exact bitmap mapping and reshape hooks

[Yu Kuai <yukuai@kernel.org>]

From: Yu Kuai <yukuai@fygo.io>

Add bitmap mapping and reshape hooks needed by llbitmap reshape
support without teaching md core to account a single bio against
multiple bitmap ranges.

This also adds the old/new bitmap geometry helpers used by
personalities to describe reshape mapping to llbitmap.

Signed-off-by: Yu Kuai <yukuai@fygo.io>
---
 drivers/md/md-bitmap.c   |  8 ++++++++
 drivers/md/md-bitmap.h   |  8 ++++++++
 drivers/md/md-llbitmap.c |  8 ++++++++
 drivers/md/md.c          | 12 ++++++++----
 drivers/md/md.h          |  4 ++++
 5 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 028b9ca8ce52..e10296788cdd 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1727,10 +1727,17 @@ static void bitmap_start_write(struct mddev *mddev, sector_t offset,
 		else
 			sectors = 0;
 	}
 }
 
+static void bitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+				 unsigned long *sectors)
+{
+	if (mddev->pers->bitmap_sector)
+		mddev->pers->bitmap_sector(mddev, offset, sectors);
+}
+
 static void bitmap_end_write(struct mddev *mddev, sector_t offset,
 			     unsigned long sectors)
 {
 	struct bitmap *bitmap = mddev->bitmap;
 
@@ -3075,10 +3082,11 @@ static struct bitmap_operations bitmap_ops = {
 	.load			= bitmap_load,
 	.destroy		= bitmap_destroy,
 	.flush			= bitmap_flush,
 	.write_all		= bitmap_write_all,
 	.dirty_bits		= bitmap_dirty_bits,
+	.prepare_range		= bitmap_prepare_range,
 	.unplug			= bitmap_unplug,
 	.daemon_work		= bitmap_daemon_work,
 
 	.start_behind_write	= bitmap_start_behind_write,
 	.end_behind_write	= bitmap_end_behind_write,
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 214f623c7e79..f0136fc02feb 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -91,10 +91,18 @@ struct bitmap_operations {
 	void (*destroy)(struct mddev *mddev);
 	void (*flush)(struct mddev *mddev);
 	void (*write_all)(struct mddev *mddev);
 	void (*dirty_bits)(struct mddev *mddev, unsigned long s,
 			   unsigned long e);
+	/* Prepare a range for this bitmap implementation. */
+	void (*prepare_range)(struct mddev *mddev,
+			      sector_t *offset,
+			      unsigned long *sectors);
+	void (*reshape_finish)(struct mddev *mddev);
+	int (*reshape_can_start)(struct mddev *mddev);
+	void (*reshape_mark)(struct mddev *mddev, sector_t old_pos,
+			     sector_t new_pos);
 	void (*unplug)(struct mddev *mddev, bool sync);
 	void (*daemon_work)(struct mddev *mddev);
 
 	void (*start_behind_write)(struct mddev *mddev);
 	void (*end_behind_write)(struct mddev *mddev);
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 1adc5b117821..bcf34f0c9af6 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1186,10 +1186,17 @@ static void llbitmap_destroy(struct mddev *mddev)
 	llbitmap_free_pages(llbitmap);
 	kfree(llbitmap);
 	mutex_unlock(&mddev->bitmap_info.mutex);
 }
 
+static void llbitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+				   unsigned long *sectors)
+{
+	if (mddev->pers->bitmap_sector)
+		mddev->pers->bitmap_sector(mddev, offset, sectors);
+}
+
 static void llbitmap_start_write(struct mddev *mddev, sector_t offset,
 				 unsigned long sectors)
 {
 	struct llbitmap *llbitmap = mddev->bitmap;
 	unsigned long start = offset >> llbitmap->chunkshift;
@@ -1775,10 +1782,11 @@ static struct bitmap_operations llbitmap_ops = {
 	.cond_end_sync		= llbitmap_cond_end_sync,
 
 	.update_sb		= llbitmap_update_sb,
 	.get_stats		= llbitmap_get_stats,
 	.dirty_bits		= llbitmap_dirty_bits,
+	.prepare_range		= llbitmap_prepare_range,
 	.write_all		= llbitmap_write_all,
 
 	.groups			= md_llbitmap_groups,
 };
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 096bb64e87bd..08eabc7e5a71 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9359,21 +9359,25 @@ void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
 	mddev_trace_remap(mddev, discard_bio, bio->bi_iter.bi_sector);
 	submit_bio_noacct(discard_bio);
 }
 EXPORT_SYMBOL_GPL(md_submit_discard_bio);
 
+static void md_bitmap_prepare_range(struct mddev *mddev, sector_t *offset,
+				    unsigned long *sectors)
+{
+	mddev->bitmap_ops->prepare_range(mddev, offset, sectors);
+}
+
 static void md_bitmap_start(struct mddev *mddev,
 			    struct md_io_clone *md_io_clone)
 {
 	md_bitmap_fn *fn = unlikely(md_io_clone->rw == STAT_DISCARD) ?
 			   mddev->bitmap_ops->start_discard :
 			   mddev->bitmap_ops->start_write;
 
-	if (mddev->pers->bitmap_sector)
-		mddev->pers->bitmap_sector(mddev, &md_io_clone->offset,
-					   &md_io_clone->sectors);
-
+	md_bitmap_prepare_range(mddev, &md_io_clone->offset,
+				&md_io_clone->sectors);
 	fn(mddev, md_io_clone->offset, md_io_clone->sectors);
 }
 
 static void md_bitmap_end(struct mddev *mddev, struct md_io_clone *md_io_clone)
 {
diff --git a/drivers/md/md.h b/drivers/md/md.h
index d8daf0f75cbb..110cf0f8b107 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -796,10 +796,14 @@ struct md_personality
 	/* Changes the consistency policy of an active array. */
 	int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
 	/* convert io ranges from array to bitmap */
 	void (*bitmap_sector)(struct mddev *mddev, sector_t *offset,
 			      unsigned long *sectors);
+	void (*bitmap_sector_map)(struct mddev *mddev, sector_t *offset,
+				  unsigned long *sectors, bool previous);
+	sector_t (*bitmap_sync_size)(struct mddev *mddev, bool previous);
+	sector_t (*bitmap_array_sectors)(struct mddev *mddev, bool previous);
 };
 
 struct md_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct mddev *, char *);
-- 
2.51.0