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-rw-r--r--blockdev.c101
1 files changed, 80 insertions, 21 deletions
diff --git a/blockdev.c b/blockdev.c
index 3848a9c8ab..7f2561081e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1562,7 +1562,12 @@ static void external_snapshot_prepare(BlkActionState *common,
goto out;
}
- if (state->new_bs->backing != NULL) {
+ if (state->new_bs->drv->is_filter) {
+ error_setg(errp, "Filters cannot be used as overlays");
+ goto out;
+ }
+
+ if (bdrv_cow_child(state->new_bs)) {
error_setg(errp, "The overlay already has a backing image");
goto out;
}
@@ -1736,7 +1741,13 @@ static void drive_backup_prepare(BlkActionState *common, Error **errp)
* 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;
}
@@ -1756,9 +1767,14 @@ static void drive_backup_prepare(BlkActionState *common, Error **errp)
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,
@@ -2528,7 +2544,9 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
}
/* Check for op blockers in the whole chain between bs and base */
- for (iter = bs; iter && iter != base_bs; iter = backing_bs(iter)) {
+ for (iter = bs; iter && iter != base_bs;
+ iter = bdrv_filter_or_cow_bs(iter))
+ {
if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) {
goto out;
}
@@ -2584,6 +2602,7 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
AioContext *aio_context;
Error *local_err = NULL;
int job_flags = JOB_DEFAULT;
+ uint64_t top_perm, top_shared;
if (!has_speed) {
speed = 0;
@@ -2685,7 +2704,9 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
assert(bdrv_get_aio_context(base_bs) == aio_context);
- for (iter = top_bs; iter != backing_bs(base_bs); iter = backing_bs(iter)) {
+ for (iter = top_bs; iter != bdrv_filter_or_cow_bs(base_bs);
+ iter = bdrv_filter_or_cow_bs(iter))
+ {
if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {
goto out;
}
@@ -2697,14 +2718,38 @@ void qmp_block_commit(bool has_job_id, const char *job_id, const char *device,
goto out;
}
- if (top_bs == bs) {
+ /*
+ * Active commit is required if and only if someone has taken a
+ * WRITE permission on the top node. Historically, we have always
+ * used active commit for top nodes, so continue that practice
+ * lest we possibly break clients that rely on this behavior, e.g.
+ * to later attach this node to a writing parent.
+ * (Active commit is never really wrong.)
+ */
+ bdrv_get_cumulative_perm(top_bs, &top_perm, &top_shared);
+ if (top_perm & BLK_PERM_WRITE ||
+ bdrv_skip_filters(top_bs) == bdrv_skip_filters(bs))
+ {
if (has_backing_file) {
- error_setg(errp, "'backing-file' specified,"
- " but 'top' is the active layer");
+ if (bdrv_skip_filters(top_bs) == bdrv_skip_filters(bs)) {
+ error_setg(errp, "'backing-file' specified,"
+ " but 'top' is the active layer");
+ } else {
+ error_setg(errp, "'backing-file' specified, but 'top' has a "
+ "writer on it");
+ }
goto out;
}
- commit_active_start(has_job_id ? job_id : NULL, bs, base_bs,
- job_flags, speed, on_error,
+ if (!has_job_id) {
+ /*
+ * Emulate here what block_job_create() does, because it
+ * is possible that @bs != @top_bs (the block job should
+ * be named after @bs, even if @top_bs is the actual
+ * source)
+ */
+ job_id = bdrv_get_device_name(bs);
+ }
+ commit_active_start(job_id, top_bs, base_bs, job_flags, speed, on_error,
filter_node_name, NULL, NULL, false, &local_err);
} else {
BlockDriverState *overlay_bs = bdrv_find_overlay(bs, top_bs);
@@ -2892,6 +2937,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
bool has_auto_dismiss, bool auto_dismiss,
Error **errp)
{
+ BlockDriverState *unfiltered_bs;
int job_flags = JOB_DEFAULT;
if (!has_speed) {
@@ -2943,10 +2989,19 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
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;
@@ -2993,7 +3048,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs,
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;
@@ -3028,12 +3083,12 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
}
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);
@@ -3059,7 +3114,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
/* 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 */
@@ -3067,15 +3122,19 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
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:
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2025-04-28 21:49:43 +0200