From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49732) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1co5Fg-0000bL-Mq for qemu-devel@nongnu.org; Wed, 15 Mar 2017 05:29:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1co5Ff-0000L4-I2 for qemu-devel@nongnu.org; Wed, 15 Mar 2017 05:29:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38790) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1co5Ff-0000KA-99 for qemu-devel@nongnu.org; Wed, 15 Mar 2017 05:29:51 -0400 From: Stefan Hajnoczi Date: Wed, 15 Mar 2017 17:29:33 +0800 Message-Id: <20170315092940.1367-2-stefanha@redhat.com> In-Reply-To: <20170315092940.1367-1-stefanha@redhat.com> References: <20170315092940.1367-1-stefanha@redhat.com> Subject: [Qemu-devel] [RFC v2 1/8] block: add bdrv_measure() API List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Nir Soffer , Kevin Wolf , Maor Lipchuk , "Daniel P. Berrange" , Eric Blake , Alberto Garcia , John Snow , Stefan Hajnoczi bdrv_measure() provides a conservative maximum for the size of a new image. This information is handy if storage needs to be allocated (e.g. a SAN or an LVM volume) ahead of time. Signed-off-by: Stefan Hajnoczi --- qapi/block-core.json | 19 +++++++++++++++++++ include/block/block.h | 4 ++++ include/block/block_int.h | 2 ++ block.c | 33 +++++++++++++++++++++++++++++++++ 4 files changed, 58 insertions(+) diff --git a/qapi/block-core.json b/qapi/block-core.json index 786b39e..673569d 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -463,6 +463,25 @@ '*dirty-bitmaps': ['BlockDirtyInfo'] } } ## +# @BlockMeasureInfo: +# +# Image size calculation information. This structure describes the size +# requirements for creating a new image. +# +# @required-bytes: Amount of space required for image creation. This value is +# the host file size including sparse file regions. A new 5 +# GB raw file therefore has a required size of 5 GB, not 0 +# bytes. +# +# @fully-allocated-bytes: Space required once data has been written to all +# sectors +# +# Since: 2.10 +## +{ 'struct': 'BlockMeasureInfo', + 'data': {'required-bytes': 'int', 'fully-allocated-bytes': 'int'} } + +## # @query-block: # # Get a list of BlockInfo for all virtual block devices. diff --git a/include/block/block.h b/include/block/block.h index 5149260..43c789f 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -298,6 +298,10 @@ int bdrv_truncate(BdrvChild *child, int64_t offset); int64_t bdrv_nb_sectors(BlockDriverState *bs); int64_t bdrv_getlength(BlockDriverState *bs); int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); +void bdrv_measure(BlockDriver *drv, QemuOpts *opts, + BlockDriverState *in_bs, + BlockMeasureInfo *info, + 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 6c699ac..45a7fbe 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -201,6 +201,8 @@ struct BlockDriver { int64_t (*bdrv_getlength)(BlockDriverState *bs); bool has_variable_length; int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs); + void (*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, + BlockMeasureInfo *info, Error **errp); int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov); diff --git a/block.c b/block.c index cb57370..532a4d1 100644 --- a/block.c +++ b/block.c @@ -3260,6 +3260,39 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) return -ENOTSUP; } +/* + * bdrv_measure: + * @drv: Format driver + * @opts: Creation options + * @in_bs: Existing image containing data for new image (may be NULL) + * @info: Result object + * @errp: Error object + * + * 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 are 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. + */ +void bdrv_measure(BlockDriver *drv, QemuOpts *opts, + BlockDriverState *in_bs, BlockMeasureInfo *info, + Error **errp) +{ + if (!drv->bdrv_measure) { + error_setg(errp, "Block driver '%s' does not support size measurement", + drv->format_name); + return; + } + + drv->bdrv_measure(opts, in_bs, info, errp); +} + /** * Return number of sectors on success, -errno on error. */ -- 2.9.3