The code already don't freeze base node and we try to make it prepared
for the situation when base node is changed during the operation. In
other words, block-stream doesn't own base node.
Let's introduce a new interface which should replace the current one,
which will in better relations with the code. Specifying bottom node
instead of base, and requiring it to be non-filter gives us the
following benefits:
- drop difference between above_base and base_overlay, which will be
renamed to just bottom, when old interface dropped
- clean way to work with parallel streams/commits on the same backing
chain, which otherwise become a problem when we introduce a filter
for stream job
- cleaner interface. Nobody will surprised the fact that base node may
disappear during block-stream, when there is no word about "base" in
the interface.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
qapi/block-core.json | 8 +++--
include/block/block_int.h | 1 +
block/monitor/block-hmp-cmds.c | 3 +-
block/stream.c | 50 +++++++++++++++++++---------
blockdev.c | 61 ++++++++++++++++++++++++++++------
5 files changed, 94 insertions(+), 29 deletions(-)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 04055ef50c..5d6681a35d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2522,6 +2522,10 @@
# @base-node: the node name of the backing file.
# It cannot be set if @base is also set. (Since 2.8)
#
+# @bottom: the last node in the chain that should be streamed into
+# top. It cannot be set any of @base, @base-node or @backing-file
@@ -2551,8 +2567,33 @@ void qmp_block_stream(bool has_job_id, const char
*job_id, const char *device,
bdrv_refresh_filename(base_bs);
}
- /* Check for op blockers in the whole chain between bs and base */
- for (iter = bs; iter && iter != base_bs;
+ if (has_bottom) {
+ bottom_bs = bdrv_lookup_bs(NULL, bottom, errp);
+ if (!bottom_bs) {
+ goto out;
+ }
+ if (!bottom_bs->drv) {
+ error_setg(errp, "Node '%s' is not open", bottom);
+ goto out;
+ }
+ if (bottom_bs->drv->is_filter) {
+ error_setg(errp, "Node '%s' is filter, use non-filter node"
+ "as 'bottom'", bottom);