mirror: Deal with filters
This includes some permission limiting (for example, we only need to
take the RESIZE permission for active commits where the base is smaller
than the top).
base_overlay is introduced so we can query bdrv_is_allocated_above() on
it - we cannot do that with base itself, because a filter's block_status
is the same as its child node, so if there are filters on base,
bdrv_is_allocated_above() on base would return information including
base.
Use this opportunity to rename qmp_drive_mirror()'s "source" BDS to
"target_backing_bs", because that is what it really refers to.
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/blockdev.c b/blockdev.c
index 57ee41b..73d96ce 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2899,6 +2899,7 @@
bool has_auto_dismiss, bool auto_dismiss,
Error **errp)
{
+ BlockDriverState *unfiltered_bs;
int job_flags = JOB_DEFAULT;
if (!has_speed) {
@@ -2950,10 +2951,19 @@
return;
}
- if (!bs->backing && sync == MIRROR_SYNC_MODE_TOP) {
+ if (!bdrv_backing_chain_next(bs) && sync == MIRROR_SYNC_MODE_TOP) {
sync = MIRROR_SYNC_MODE_FULL;
}
+ if (!has_replaces) {
+ /* We want to mirror from @bs, but keep implicit filters on top */
+ unfiltered_bs = bdrv_skip_implicit_filters(bs);
+ if (unfiltered_bs != bs) {
+ replaces = unfiltered_bs->node_name;
+ has_replaces = true;
+ }
+ }
+
if (has_replaces) {
BlockDriverState *to_replace_bs;
AioContext *replace_aio_context;
@@ -3000,7 +3010,7 @@
void qmp_drive_mirror(DriveMirror *arg, Error **errp)
{
BlockDriverState *bs;
- BlockDriverState *source, *target_bs;
+ BlockDriverState *target_backing_bs, *target_bs;
AioContext *aio_context;
AioContext *old_context;
BlockMirrorBackingMode backing_mode;
@@ -3035,12 +3045,12 @@
}
flags = bs->open_flags | BDRV_O_RDWR;
- source = backing_bs(bs);
- if (!source && arg->sync == MIRROR_SYNC_MODE_TOP) {
+ target_backing_bs = bdrv_cow_bs(bdrv_skip_filters(bs));
+ if (!target_backing_bs && arg->sync == MIRROR_SYNC_MODE_TOP) {
arg->sync = MIRROR_SYNC_MODE_FULL;
}
if (arg->sync == MIRROR_SYNC_MODE_NONE) {
- source = bs;
+ target_backing_bs = bs;
}
size = bdrv_getlength(bs);
@@ -3066,7 +3076,7 @@
/* Don't open backing image in create() */
flags |= BDRV_O_NO_BACKING;
- if ((arg->sync == MIRROR_SYNC_MODE_FULL || !source)
+ if ((arg->sync == MIRROR_SYNC_MODE_FULL || !target_backing_bs)
&& arg->mode != NEW_IMAGE_MODE_EXISTING)
{
/* create new image w/o backing file */
@@ -3074,15 +3084,19 @@
bdrv_img_create(arg->target, format,
NULL, NULL, NULL, size, flags, false, &local_err);
} else {
+ /* Implicit filters should not appear in the filename */
+ BlockDriverState *explicit_backing =
+ bdrv_skip_implicit_filters(target_backing_bs);
+
switch (arg->mode) {
case NEW_IMAGE_MODE_EXISTING:
break;
case NEW_IMAGE_MODE_ABSOLUTE_PATHS:
/* create new image with backing file */
- bdrv_refresh_filename(source);
+ bdrv_refresh_filename(explicit_backing);
bdrv_img_create(arg->target, format,
- source->filename,
- source->drv->format_name,
+ explicit_backing->filename,
+ explicit_backing->drv->format_name,
NULL, size, flags, false, &local_err);
break;
default:
