From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59629) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cvmbp-0006fT-Dw for qemu-devel@nongnu.org; Wed, 05 Apr 2017 11:12:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cvmbm-0007mB-8A for qemu-devel@nongnu.org; Wed, 05 Apr 2017 11:12:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54280) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cvmbl-0007lt-VX for qemu-devel@nongnu.org; Wed, 05 Apr 2017 11:12:30 -0400 From: Stefan Hajnoczi Date: Wed, 5 Apr 2017 16:11:45 +0100 Message-Id: <20170405151148.16363-7-stefanha@redhat.com> In-Reply-To: <20170405151148.16363-1-stefanha@redhat.com> References: <20170405151148.16363-1-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v4 6/9] qcow2: add bdrv_measure() support 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 Use qcow2_calc_prealloc_size() to get the required file size. Signed-off-by: Stefan Hajnoczi --- block/qcow2.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 0181d72..a2c7f97 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2942,6 +2942,127 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) return 0; } +static void qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, + BlockMeasureInfo *info, Error **errp) +{ + Error *local_err = NULL; + uint64_t required = 0; /* bytes that contribute to required size */ + uint64_t virtual_size; /* disk size as seen by guest */ + uint64_t refcount_bits; + size_t cluster_size; + int version; + char *optstr; + PreallocMode prealloc; + bool has_backing_file; + + /* Parse image creation options */ + cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); + if (local_err) { + goto err; + } + + version = qcow2_opt_get_version_del(opts, &local_err); + if (local_err) { + goto err; + } + + refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err); + if (local_err) { + goto err; + } + + optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); + prealloc = qapi_enum_parse(PreallocMode_lookup, optstr, + PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, + &local_err); + g_free(optstr); + if (local_err) { + goto err; + } + + optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); + has_backing_file = !!optstr; + g_free(optstr); + + virtual_size = align_offset(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), + cluster_size); + + /* Account for input image */ + if (in_bs) { + int64_t ssize = bdrv_getlength(in_bs); + if (ssize < 0) { + error_setg_errno(errp, -ssize, "Unable to get image virtual_size"); + return; + } + + virtual_size = align_offset(ssize, cluster_size); + + if (has_backing_file) { + /* We don't how much of the backing chain is shared by the input + * image and the new image file. In the worst case the new image's + * backing file has nothing in common with the input image. Be + * conservative and assume all clusters need to be written. + */ + required = virtual_size; + } else { + int cluster_sectors = cluster_size / BDRV_SECTOR_SIZE; + int64_t sector_num; + int pnum = 0; + + for (sector_num = 0; + sector_num < ssize / BDRV_SECTOR_SIZE; + sector_num += pnum) { + int nb_sectors = MAX(ssize / BDRV_SECTOR_SIZE - sector_num, + INT_MAX); + BlockDriverState *file; + int64_t ret; + + ret = bdrv_get_block_status_above(in_bs, NULL, + sector_num, nb_sectors, + &pnum, &file); + if (ret < 0) { + error_setg_errno(errp, -ret, "Unable to get block status"); + return; + } + + if (ret & BDRV_BLOCK_ZERO) { + /* Skip zero regions (safe with no backing file) */ + } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == + (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { + /* Extend pnum to end of cluster for next iteration */ + pnum = ROUND_UP(sector_num + pnum, cluster_sectors) - + sector_num; + + /* Count clusters we've seen */ + required += (sector_num % cluster_sectors + pnum) * + BDRV_SECTOR_SIZE; + } + } + } + } + + /* Take into account preallocation. Nothing special is needed for + * PREALLOC_MODE_METADATA since metadata is always counted. + */ + if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { + required = virtual_size; + } + + info->fully_allocated = + qcow2_calc_prealloc_size(virtual_size, cluster_size, + ctz32(refcount_bits)); + + /* Remove data clusters that are not required. This overestimates the + * required size because metadata needed for the fully allocated file is + * still counted. + */ + info->required = info->fully_allocated - virtual_size + required; + return; + +err: + error_propagate(errp, local_err); +} + static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcow2State *s = bs->opaque; @@ -3489,6 +3610,7 @@ BlockDriver bdrv_qcow2 = { .bdrv_snapshot_delete = qcow2_snapshot_delete, .bdrv_snapshot_list = qcow2_snapshot_list, .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, + .bdrv_measure = qcow2_measure, .bdrv_get_info = qcow2_get_info, .bdrv_get_specific_info = qcow2_get_specific_info, -- 2.9.3