[PATCH v3 07/11] md/md-bitmap: add a new method skip_sync_blocks() in bitmap_operations

[Yu Kuai]

From: Yu Kuai <yuku...@huawei.com>

This method is used to check if blocks can be skipped before calling
into pers->sync_request(), llbitmap will use this method to skip
resync for unwritten/clean data blocks, and recovery/check/repair for
unwritten data blocks;

Signed-off-by: Yu Kuai <yuku...@huawei.com>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Xiao Ni <x...@redhat.com>
Reviewed-by: Hannes Reinecke <h...@suse.de>
---
 drivers/md/md-bitmap.h | 1 +
 drivers/md/md.c        | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 8616ced49077..95453696c68e 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -89,6 +89,7 @@ struct bitmap_operations {
        md_bitmap_fn *start_discard;
        md_bitmap_fn *end_discard;
 
+       sector_t (*skip_sync_blocks)(struct mddev *mddev, sector_t offset);
        bool (*start_sync)(struct mddev *mddev, sector_t offset,
                           sector_t *blocks, bool degraded);
        void (*end_sync)(struct mddev *mddev, sector_t offset, sector_t 
*blocks);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 639b0143cbb1..4a9e3f7cbfe3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9394,6 +9394,12 @@ void md_do_sync(struct md_thread *thread)
                if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                        break;
 
+               if (mddev->bitmap_ops && mddev->bitmap_ops->skip_sync_blocks) {
+                       sectors = mddev->bitmap_ops->skip_sync_blocks(mddev, j);
+                       if (sectors)
+                               goto update;
+               }
+
                sectors = mddev->pers->sync_request(mddev, j, max_sectors,
                                                    &skipped);
                if (sectors == 0) {
@@ -9409,6 +9415,7 @@ void md_do_sync(struct md_thread *thread)
                if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
                        break;
 
+update:
                j += sectors;
                if (j > max_sectors)
                        /* when skipping, extra large numbers can be returned. 
*/
-- 
2.39.2