diff options
| -rw-r--r-- | block.c | 21 | ||||
| -rw-r--r-- | include/block/block.h | 1 | ||||
| -rw-r--r-- | include/block/block_int.h | 7 |
3 files changed, 29 insertions, 0 deletions
diff --git a/block.c b/block.c index 3e698e9cab..874a29a983 100644 --- a/block.c +++ b/block.c @@ -5078,6 +5078,27 @@ int bdrv_has_zero_init(BlockDriverState *bs) return 0; } +int bdrv_has_zero_init_truncate(BlockDriverState *bs) +{ + if (!bs->drv) { + return 0; + } + + if (bs->backing) { + /* Depends on the backing image length, but better safe than sorry */ + return 0; + } + if (bs->drv->bdrv_has_zero_init_truncate) { + return bs->drv->bdrv_has_zero_init_truncate(bs); + } + if (bs->file && bs->drv->is_filter) { + return bdrv_has_zero_init_truncate(bs->file->bs); + } + + /* safe default */ + return 0; +} + bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) { BlockDriverInfo bdi; diff --git a/include/block/block.h b/include/block/block.h index 89e40318cf..124ad40809 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -443,6 +443,7 @@ int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); int bdrv_has_zero_init_1(BlockDriverState *bs); int bdrv_has_zero_init(BlockDriverState *bs); +int bdrv_has_zero_init_truncate(BlockDriverState *bs); bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs); bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); int bdrv_block_status(BlockDriverState *bs, int64_t offset, diff --git a/include/block/block_int.h b/include/block/block_int.h index 8fa011654a..ceec8c2f56 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -419,9 +419,16 @@ struct BlockDriver { /* * Returns 1 if newly created images are guaranteed to contain only * zeros, 0 otherwise. + * Must return 0 if .bdrv_has_zero_init_truncate() returns 0. */ int (*bdrv_has_zero_init)(BlockDriverState *bs); + /* + * Returns 1 if new areas added by growing the image with + * PREALLOC_MODE_OFF contain only zeros, 0 otherwise. + */ + int (*bdrv_has_zero_init_truncate)(BlockDriverState *bs); + /* Remove fd handlers, timers, and other event loop callbacks so the event * loop is no longer in use. Called with no in-flight requests and in * depth-first traversal order with parents before child nodes. |