dirty-bitmap: Change bdrv_get_dirty_locked() to take bytes

Half the callers were already scaling bytes to sectors; the other
half can eventually be simplified to use byte iteration.  Both
callers were already using the result as a bool, so make that
explicit.  Making the change also makes it easier for a future
dirty-bitmap patch to offload scaling over to the internal hbitmap.

Remember, asking whether a byte is dirty is effectively asking
whether the entire granularity containing the byte is dirty, since
we only track dirtiness by granularity.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/dirty-bitmap.c

@@ -438,13 +438,13 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
-int bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                          int64_t sector)
+bool bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+                           int64_t offset)
 {
     if (bitmap) {
-        return hbitmap_get(bitmap->bitmap, sector);
+        return hbitmap_get(bitmap->bitmap, offset >> BDRV_SECTOR_BITS);
     } else {
-        return 0;
+        return false;
     }
 }
 

block/mirror.c

@@ -361,8 +361,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
         int64_t next_offset = offset + nb_chunks * s->granularity;
         int64_t next_chunk = next_offset / s->granularity;
         if (next_offset >= s->bdev_length ||
-            !bdrv_get_dirty_locked(source, s->dirty_bitmap,
-                                   next_offset >> BDRV_SECTOR_BITS)) {
+            !bdrv_get_dirty_locked(source, s->dirty_bitmap, next_offset)) {
             break;
         }
         if (test_bit(next_chunk, s->in_flight_bitmap)) {

include/block/dirty-bitmap.h

@@ -72,8 +72,8 @@ void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap,
 /* Functions that require manual locking.  */
 void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_bitmap_unlock(BdrvDirtyBitmap *bitmap);
-int bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                          int64_t sector);
+bool bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+                           int64_t offset);
 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                   int64_t cur_sector, int64_t nr_sectors);
 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,

migration/block.c

@@ -535,7 +535,8 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
             blk_mig_unlock();
         }
         bdrv_dirty_bitmap_lock(bmds->dirty_bitmap);
-        if (bdrv_get_dirty_locked(bs, bmds->dirty_bitmap, sector)) {
+        if (bdrv_get_dirty_locked(bs, bmds->dirty_bitmap,
+                                  sector * BDRV_SECTOR_SIZE)) {
             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
                 nr_sectors = total_sectors - sector;
             } else {