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
---
qapi/block-core.json | 6 ++-
block/mirror.c | 118 +--
blockdev.c | 32
3 files changed, 118 insertions(+), 38 deletions(-)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index f8f42cc836..8d180b584c 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1948,7 +1948,8 @@
#
# @replaces: with sync=full graph node name to be replaced by the new
#image when a whole image copy is done. This can be used to repair
-#broken Quorum files. (Since 2.1)
+#broken Quorum files. By default, @device is replaced, although
+#implicitly created filters on it are kept. (Since 2.1)
#
# @mode: whether and how QEMU should create a new image, default is
#'absolute-paths'.
@@ -2259,7 +2260,8 @@
#
# @replaces: with sync=full graph node name to be replaced by the new
#image when a whole image copy is done. This can be used to repair
-#broken Quorum files.
+#broken Quorum files. By default, @device is replaced, although
+#implicitly created filters on it are kept.
#
# @speed: the maximum speed, in bytes per second
#
diff --git a/block/mirror.c b/block/mirror.c
index e8e8844afc..f16b0d62bc 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -42,6 +42,7 @@ typedef struct MirrorBlockJob {
BlockBackend *target;
BlockDriverState *mirror_top_bs;
BlockDriverState *base;
+BlockDriverState *base_overlay;
/* The name of the graph node to replace */
char *replaces;
@@ -677,8 +678,10 @@ static int mirror_exit_common(Job *job)
&error_abort);
if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
BlockDriverState *backing = s->is_none_mode ? src : s->base;
-if (backing_bs(target_bs) != backing) {
-bdrv_set_backing_hd(target_bs, backing, &local_err);
+BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs);
+
+if (bdrv_cow_bs(unfiltered_target) != backing) {
+bdrv_set_backing_hd(unfiltered_target, backing, &local_err);
if (local_err) {
error_report_err(local_err);
local_err = NULL;
@@ -740,7 +743,7 @@ static int mirror_exit_common(Job *job)
* valid.
*/
block_job_remove_all_bdrv(bjob);
-bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);
+bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
/* We just changed the BDS the job BB refers to (with either or both of the
* bdrv_replace_node() calls), so switch the BB back so the cleanup does
@@ -786,7 +789,6 @@ static void coroutine_fn mirror_throttle(MirrorBlockJob *s)
static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
{
int64_t offset;
-BlockDriverState *base = s->base;
BlockDriverState *bs = s->mirror_top_bs->backing->bs;
BlockDriverState *target_bs = blk_bs(s->target);
int ret;
@@ -837,7 +839,8 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
return 0;
}
-ret = bdrv_is_allocated_above(bs, base, false, offset, bytes, &count);
+ret = bdrv_is_allocated_above(bs, s->base_overlay, true, offset, bytes,
+ &count);
if (ret < 0) {
return ret;
}
@@ -936,7 +939,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
} else {
s->target_cluster_size = BDRV_SECTOR_SIZE;
}
-if (backing_filename[0] && !target_bs->backing &&
+if (backing_filename[0] && !bdrv_backing_chain_next(target_bs) &&
s->granularity < s->target_cluster_size) {
s->buf_size = MAX(s->buf_size, s->target_cluster_size);
s->cow_bitmap = bitmap_new(length);
@@ -1116,8 +1119,9 @@ static void mirror_complete(Job *job, Error **errp)
if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) {
int ret;
-assert(!target->backing);
-ret = bdrv_open_backing_file(target, NULL, "backing", errp);
+assert(!bdrv_backing_chain_next(target));
+ret = bdrv_open_backing_file(bdrv_skip_filters(target), NULL,
+ "backing", errp);
if (ret < 0) {
return;
}
@@ -1555,8 +1559,8 @@ stat
