diff options
| -rw-r--r-- | block.c | 35 | ||||
| -rw-r--r-- | include/block/block.h | 2 | ||||
| -rw-r--r-- | include/block/block_int.h | 2 | ||||
| -rw-r--r-- | qapi/block-core.json | 25 |
4 files changed, 64 insertions, 0 deletions
@@ -3463,6 +3463,41 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) return -ENOTSUP; } +/* + * bdrv_measure: + * @drv: Format driver + * @opts: Creation options for new image + * @in_bs: Existing image containing data for new image (may be NULL) + * @errp: Error object + * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo()) + * or NULL on error + * + * Calculate file size required to create a new image. + * + * If @in_bs is given then space for allocated clusters and zero clusters + * from that image are included in the calculation. If @opts contains a + * backing file that is shared by @in_bs then backing clusters may be omitted + * from the calculation. + * + * If @in_bs is NULL then the calculation includes no allocated clusters + * unless a preallocation option is given in @opts. + * + * Note that @in_bs may use a different BlockDriver from @drv. + * + * If an error occurs the @errp pointer is set. + */ +BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, + BlockDriverState *in_bs, Error **errp) +{ + if (!drv->bdrv_measure) { + error_setg(errp, "Block driver '%s' does not support size measurement", + drv->format_name); + return NULL; + } + + return drv->bdrv_measure(opts, in_bs, errp); +} + /** * Return number of sectors on success, -errno on error. */ diff --git a/include/block/block.h b/include/block/block.h index f0fdbe8..96edc85 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -306,6 +306,8 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp); int64_t bdrv_nb_sectors(BlockDriverState *bs); int64_t bdrv_getlength(BlockDriverState *bs); int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); +BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, + BlockDriverState *in_bs, Error **errp); void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr); void bdrv_refresh_limits(BlockDriverState *bs, Error **errp); int bdrv_commit(BlockDriverState *bs); diff --git a/include/block/block_int.h b/include/block/block_int.h index 58d4ffd..d0cd8a3 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -209,6 +209,8 @@ struct BlockDriver { int64_t (*bdrv_getlength)(BlockDriverState *bs); bool has_variable_length; int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); + BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, + Error **errp); int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov); diff --git a/qapi/block-core.json b/qapi/block-core.json index 4bf11e8..c437aa5 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -488,6 +488,31 @@ '*dirty-bitmaps': ['BlockDirtyInfo'] } } ## +# @BlockMeasureInfo: +# +# Image file size calculation information. This structure describes the size +# requirements for creating a new image file. +# +# The size requirements depend on the new image file format. File size always +# equals virtual disk size for the 'raw' format, even for sparse POSIX files. +# Compact formats such as 'qcow2' represent unallocated and zero regions +# efficiently so file size may be smaller than virtual disk size. +# +# The values are upper bounds that are guaranteed to fit the new image file. +# Subsequent modification, such as internal snapshot or bitmap creation, may +# require additional space and is not covered here. +# +# @required: Size required for a new image file, in bytes. +# +# @fully-allocated: Image file size, in bytes, once data has been written +# to all sectors. +# +# Since: 2.10 +## +{ 'struct': 'BlockMeasureInfo', + 'data': {'required': 'int', 'fully-allocated': 'int'} } + +## # @query-block: # # Get a list of BlockInfo for all virtual block devices. |