This adds 2 wrappers to read the unallocated_blocks_are_zero and can_write_zeroes_with_unmap info from the BDI. The wrappers are required to check for the existence of a backing_hd and if the devices are opened with the correct flags.
Signed-off-by: Peter Lieven <p...@kamp.de> --- block.c | 30 ++++++++++++++++++++++++++++++ include/block/block.h | 2 ++ 2 files changed, 32 insertions(+) diff --git a/block.c b/block.c index 0d97ce6..0601b02 100644 --- a/block.c +++ b/block.c @@ -3094,6 +3094,36 @@ int bdrv_has_zero_init(BlockDriverState *bs) return 0; } +bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) +{ + BlockDriverInfo bdi; + + if (bs->backing_hd) { + return false; + } + + if (bdrv_get_info(bs, &bdi) == 0) { + return bdi.unallocated_blocks_are_zero; + } + + return false; +} + +bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) +{ + BlockDriverInfo bdi; + + if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { + return false; + } + + if (bdrv_get_info(bs, &bdi) == 0) { + return bdi.can_write_zeroes_with_unmap; + } + + return false; +} + typedef struct BdrvCoGetBlockStatusData { BlockDriverState *bs; BlockDriverState *base; diff --git a/include/block/block.h b/include/block/block.h index 5fbab01..de0d6ab 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -344,6 +344,8 @@ int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); int bdrv_has_zero_init_1(BlockDriverState *bs); int bdrv_has_zero_init(BlockDriverState *bs); +bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs); +bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum); int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors, -- 1.7.9.5