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author | Stefan Hajnoczi <stefanha@redhat.com> | 2017-07-05 13:57:35 +0100 |
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committer | Max Reitz <mreitz@redhat.com> | 2017-07-11 17:45:00 +0200 |
commit | c501c35220856621e9677ba9e6a556948d49778e (patch) | |
tree | 67756bd19e8b6720dc9892b249a26cc74c280e5b /block | |
parent | 0eb4a8c1df6db29e835daeb954352bfaa8994374 (diff) | |
download | qemu-c501c35220856621e9677ba9e6a556948d49778e.zip qemu-c501c35220856621e9677ba9e6a556948d49778e.tar.gz qemu-c501c35220856621e9677ba9e6a556948d49778e.tar.bz2 |
qcow2: add bdrv_measure() support
Use qcow2_calc_prealloc_size() to get the required file size.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-7-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/qcow2.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index db8d81f..52dc6bf 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3426,6 +3426,142 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) return 0; } +static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, + Error **errp) +{ + Error *local_err = NULL; + BlockMeasureInfo *info; + uint64_t required = 0; /* bytes that contribute to required size */ + uint64_t virtual_size; /* disk size as seen by guest */ + uint64_t refcount_bits; + uint64_t l2_tables; + 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); + + /* Check that virtual disk size is valid */ + l2_tables = DIV_ROUND_UP(virtual_size / cluster_size, + cluster_size / sizeof(uint64_t)); + if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) { + error_setg(&local_err, "The image size is too large " + "(try using a larger cluster size)"); + goto err; + } + + /* Account for input image */ + if (in_bs) { + int64_t ssize = bdrv_getlength(in_bs); + if (ssize < 0) { + error_setg_errno(&local_err, -ssize, + "Unable to get image virtual_size"); + goto err; + } + + 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(&local_err, -ret, + "Unable to get block status"); + goto err; + } + + 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 = g_new(BlockMeasureInfo, 1); + 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 info; + +err: + error_propagate(errp, local_err); + return NULL; +} + static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcow2State *s = bs->opaque; @@ -4024,6 +4160,7 @@ 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, |