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qcow2: add bdrv_measure() support

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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>
This commit is contained in:
Stefan Hajnoczi 2017-07-05 13:57:35 +01:00 committed by Max Reitz
parent 0eb4a8c1df
commit c501c35220
1 changed files with 137 additions and 0 deletions
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137
block/qcow2.c
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@ -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,