Re: [Qemu-block] [Qemu-devel] [PATCH 09/12] dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes

[John Snow]

On 04/12/2017 01:49 PM, Eric Blake wrote:
> Some of the callers were already scaling bytes to sectors; others
> can be easily converted to pass byte offsets, all in our shift
> towards a consistent byte interface everywhere.  Making the change
> will also make it easier to write the hold-out callers to use byte
> rather than sectors for their iterations; it also makes it easier
> for a future dirty-bitmap patch to offload scaling over to the
> internal hbitmap.  Although all callers happen to pass
> sector-aligned values, make the internal scaling robust to any
> sub-sector requests.
> 
> Signed-off-by: Eric Blake <address@hidden>
> ---
>  include/block/dirty-bitmap.h |  4 ++--
>  block/dirty-bitmap.c         | 14 ++++++++++----
>  block/mirror.c               | 16 ++++++++--------
>  migration/block.c            |  7 +++++--
>  4 files changed, 25 insertions(+), 16 deletions(-)
> 
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index b8434e5..fdff1e2 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -37,9 +37,9 @@ DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap 
> *bitmap);
>  bool bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
>                      int64_t offset);
>  void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> -                           int64_t cur_sector, int64_t nr_sectors);
> +                           int64_t offset, int64_t bytes);
>  void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> -                             int64_t cur_sector, int64_t nr_sectors);
> +                             int64_t offset, int64_t bytes);
>  BdrvDirtyBitmapIter *bdrv_dirty_meta_iter_new(BdrvDirtyBitmap *bitmap);
>  BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap);
>  void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index c8100d2..8e7822c 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -401,17 +401,23 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
>  }
> 
>  void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> -                           int64_t cur_sector, int64_t nr_sectors)
> +                           int64_t offset, int64_t bytes)
>  {
> +    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
> +
>      assert(bdrv_dirty_bitmap_enabled(bitmap));
> -    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> +    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
> +                end_sector - (offset >> BDRV_SECTOR_BITS));
>  }
> 
>  void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> -                             int64_t cur_sector, int64_t nr_sectors)
> +                             int64_t offset, int64_t bytes)
>  {
> +    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
> +
>      assert(bdrv_dirty_bitmap_enabled(bitmap));
> -    hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
> +    hbitmap_reset(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
> +                  end_sector - (offset >> BDRV_SECTOR_BITS));
>  }
> 
>  void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
> diff --git a/block/mirror.c b/block/mirror.c
> index 1e2e655..21b4f5d 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -141,8 +141,7 @@ static void mirror_write_complete(void *opaque, int ret)
>      if (ret < 0) {
>          BlockErrorAction action;
> 
> -        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> 
> BDRV_SECTOR_BITS,
> -                              op->bytes >> BDRV_SECTOR_BITS);
> +        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
>          action = mirror_error_action(s, false, -ret);
>          if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
>              s->ret = ret;
> @@ -161,8 +160,7 @@ static void mirror_read_complete(void *opaque, int ret)
>      if (ret < 0) {
>          BlockErrorAction action;
> 
> -        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> 
> BDRV_SECTOR_BITS,
> -                              op->bytes >> BDRV_SECTOR_BITS);
> +        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
>          action = mirror_error_action(s, true, -ret);
>          if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
>              s->ret = ret;
> @@ -380,8 +378,8 @@ static uint64_t coroutine_fn 
> mirror_iteration(MirrorBlockJob *s)
>       * calling bdrv_get_block_status_above could yield - if some blocks are
>       * marked dirty in this window, we need to know.
>       */
> -    bdrv_reset_dirty_bitmap(s->dirty_bitmap, offset >> BDRV_SECTOR_BITS,
> -                            nb_chunks * sectors_per_chunk);
> +    bdrv_reset_dirty_bitmap(s->dirty_bitmap, offset,
> +                            nb_chunks * s->granularity);
>      bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
>      while (nb_chunks > 0 && offset < s->bdev_length) {
>          int64_t ret;
> @@ -614,7 +612,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob 
> *s)
> 
>      if (base == NULL && !bdrv_has_zero_init(target_bs)) {
>          if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
> -            bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end);
> +            bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length);
>              return 0;
>          }
> 
> @@ -667,7 +665,9 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob 
> *s)
>          n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
>          assert(n > 0);
>          if (ret == 1) {
> -            bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
> +            bdrv_set_dirty_bitmap(s->dirty_bitmap,
> +                                  sector_num * BDRV_SECTOR_SIZE,
> +                                  n * BDRV_SECTOR_SIZE);
>          }
>          sector_num += n;
>      }
> diff --git a/migration/block.c b/migration/block.c
> index 9e21aeb..e875211 100644
> --- a/migration/block.c
> +++ b/migration/block.c
> @@ -331,7 +331,8 @@ static int mig_save_device_bulk(QEMUFile *f, 
> BlkMigDevState *bmds)
>      blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, 
> &blk->qiov,
>                                  0, blk_mig_read_cb, blk);
> 
> -    bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector, nr_sectors);
> +    bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * 
> BDRV_SECTOR_SIZE,
> +                            nr_sectors * BDRV_SECTOR_SIZE);
>      aio_context_release(blk_get_aio_context(bmds->blk));
>      qemu_mutex_unlock_iothread();
> 
> @@ -575,7 +576,9 @@ static int mig_save_device_dirty(QEMUFile *f, 
> BlkMigDevState *bmds,
>                  g_free(blk);
>              }
> 
> -            bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, sector, nr_sectors);
> +            bdrv_reset_dirty_bitmap(bmds->dirty_bitmap,
> +                                    sector * BDRV_SECTOR_SIZE,
> +                                    nr_sectors * BDRV_SECTOR_SIZE);
>              sector += nr_sectors;
>              bmds->cur_dirty = sector;
> 

Reviewed-by: John Snow <address@hidden>