diff options
Diffstat (limited to 'block/backup.c')
| -rw-r--r-- | block/backup.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/block/backup.c b/block/backup.c index 4f13bb20a5..9afa0bf3b4 100644 --- a/block/backup.c +++ b/block/backup.c @@ -297,6 +297,7 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target, { int ret; BlockDriverInfo bdi; + bool target_does_cow = bdrv_backing_chain_next(target); /* * If there is no backing file on the target, we cannot rely on COW if our @@ -304,7 +305,7 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target, * targets with a backing file, try to avoid COW if possible. */ ret = bdrv_get_info(target, &bdi); - if (ret == -ENOTSUP && !target->backing) { + if (ret == -ENOTSUP && !target_does_cow) { /* Cluster size is not defined */ warn_report("The target block device doesn't provide " "information about the block size and it doesn't have a " @@ -313,14 +314,14 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target, "this default, the backup may be unusable", BACKUP_CLUSTER_SIZE_DEFAULT); return BACKUP_CLUSTER_SIZE_DEFAULT; - } else if (ret < 0 && !target->backing) { + } else if (ret < 0 && !target_does_cow) { error_setg_errno(errp, -ret, "Couldn't determine the cluster size of the target image, " "which has no backing file"); error_append_hint(errp, "Aborting, since this may create an unusable destination image\n"); return ret; - } else if (ret < 0 && target->backing) { + } else if (ret < 0 && target_does_cow) { /* Not fatal; just trudge on ahead. */ return BACKUP_CLUSTER_SIZE_DEFAULT; } @@ -371,7 +372,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, return NULL; } - if (compress && !block_driver_can_compress(target->drv)) { + if (compress && !bdrv_supports_compressed_writes(target)) { error_setg(errp, "Compression is not supported for this drive %s", bdrv_get_device_name(target)); return NULL; |