backup: Deal with filters
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/backup-top.c b/block/backup-top.c
index af2f20f..430d1be 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -281,7 +281,7 @@
s->active = false;
bdrv_child_refresh_perms(bs, bs->backing, &error_abort);
- bdrv_replace_node(bs, backing_bs(bs), &error_abort);
+ bdrv_replace_node(bs, bs->backing->bs, &error_abort);
bdrv_set_backing_hd(bs, NULL, &error_abort);
bdrv_drained_end(bs);
diff --git a/block/backup.c b/block/backup.c
index 4f13bb2..9afa0bf 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -297,6 +297,7 @@
{
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 @@
* 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 @@
"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 @@
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;
diff --git a/blockdev.c b/blockdev.c
index 73d96ce..d53e39c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1741,7 +1741,13 @@
* on top of.
*/
if (backup->sync == MIRROR_SYNC_MODE_TOP) {
- source = backing_bs(bs);
+ /*
+ * Backup will not replace the source by the target, so none
+ * of the filters skipped here will be removed (in contrast to
+ * mirror). Therefore, we can skip all of them when looking
+ * for the first COW relationship.
+ */
+ source = bdrv_cow_bs(bdrv_skip_filters(bs));
if (!source) {
backup->sync = MIRROR_SYNC_MODE_FULL;
}
@@ -1761,9 +1767,14 @@
if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
assert(backup->format);
if (source) {
- bdrv_refresh_filename(source);
- bdrv_img_create(backup->target, backup->format, source->filename,
- source->drv->format_name, NULL,
+ /* Implicit filters should not appear in the filename */
+ BlockDriverState *explicit_backing =
+ bdrv_skip_implicit_filters(source);
+
+ bdrv_refresh_filename(explicit_backing);
+ bdrv_img_create(backup->target, backup->format,
+ explicit_backing->filename,
+ explicit_backing->drv->format_name, NULL,
size, flags, false, &local_err);
} else {
bdrv_img_create(backup->target, backup->format, NULL, NULL, NULL,
