On 02/27/2016 04:20 AM, Fam Zheng wrote:
> The added group of operations enables tracking of the changed bits in
> the dirty bitmap.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> block/dirty-bitmap.c | 51
> ++++++++++++++++++++++++++++++++++++++++++++
> include/block/dirty-bitmap.h | 9 ++++++++
> 2 files changed, 60 insertions(+)
>
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 16f73b2..5f19320 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -38,6 +38,7 @@
> */
> struct BdrvDirtyBitmap {
> HBitmap *bitmap; /* Dirty sector bitmap implementation */
> + HBitmap *meta; /* Meta dirty bitmap */
> BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
> char *name; /* Optional non-empty unique ID */
> int64_t size; /* Size of the bitmap (Number of sectors) */
> @@ -103,6 +104,56 @@ BdrvDirtyBitmap
> *bdrv_create_dirty_bitmap(BlockDriverState *bs,
> return bitmap;
> }
>
> +/* bdrv_create_meta_dirty_bitmap
> + *
> + * Create a meta dirty bitmap that tracks the changes of bits in @bitmap.
> I.e.
> + * when a dirty status bit in @bitmap is changed (either from reset to set or
> + * the other way around), its respective meta dirty bitmap bit will be marked
> + * dirty as well.
> + *
> + * @bitmap: the block dirty bitmap for which to create a meta dirty bitmap.
> + * @chunk_size: how many bytes of bitmap data does each bit in the meta
> bitmap
> + * track.
> + */
> +void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> + int chunk_size)
> +{
> + assert(!bitmap->meta);
> + bitmap->meta = hbitmap_create_meta(bitmap->bitmap,
> + chunk_size * BITS_PER_BYTE);
> +}
> +
> +void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
> +{
> + assert(bitmap->meta);
> + hbitmap_free_meta(bitmap->bitmap);
> + bitmap->meta = NULL;
> +}
> +
> +int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap, int64_t sector,
> + int nb_sectors)
> +{
> + uint64_t i;
> + int gran = bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
> +
> + /* To optimize: we can make hbitmap to internally check the range in a
> + * coarse level, or at least do it word by word. */
> + for (i = sector; i < sector + nb_sectors; i += gran) {
> + if (hbitmap_get(bitmap->meta, i)) {
> + return true;
> + }
> + }
> + return false;
> +}
> +
> +void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap, int64_t sector,
> + int nb_sectors)
> +{
> + hbitmap_reset(bitmap->meta, sector, nb_sectors);
> +}
> +
> bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap)
> {
> return bitmap->successor;
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index e1dbd8e..3b27742 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -9,6 +9,9 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState
> *bs,
> uint32_t granularity,
> const char *name,
> Error **errp);
> +void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> + int chunk_size);
> +void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap);
> int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
> BdrvDirtyBitmap *bitmap,
> Error **errp);
> @@ -37,6 +40,12 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> int64_t cur_sector, int nr_sectors);
> void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> int64_t cur_sector, int nr_sectors);
> +int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap, int64_t sector,
> + int nb_sectors);
> +void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
> + BdrvDirtyBitmap *bitmap, int64_t sector,
> + int nb_sectors);
> BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
> uint64_t first_sector);
> void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
>
Do we need to amend the teardown in bdrv_do_release_matching_dirty_bitmap?
