[PATCH v4 09/15] block: prepare block-stream for using COR-filter

[Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>]

This patch is the first one in the series where the COR-filter node
will be hard-coded for using in the block-stream job. The block jobs
may be run in parallel. Exclude conflicts with filter nodes used for
a concurrent job while checking for the blocked operations. It incurs
changes in the iotests 030::test_overlapping_4 that now passes with no
conflict because the stream job does not have a real dependency on its
base and on a filter above it.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 blockdev.c             | 11 +++++++++--
 tests/qemu-iotests/030 |  9 ++++-----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index b3c840e..97c2ba2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2763,6 +2763,7 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
     Error *local_err = NULL;
     const char *base_name = NULL;
     int job_flags = JOB_DEFAULT;
+    BlockDriverState *bottom_cow_node;
 
     if (!has_on_error) {
         on_error = BLOCKDEV_ON_ERROR_REPORT;
@@ -2807,8 +2808,14 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         base_name = base_bs->filename;
     }
 
-    /* Check for op blockers in the whole chain between bs and base */
-    for (iter = bs; iter && iter != base_bs; iter = backing_bs(iter)) {
+    bottom_cow_node = bdrv_find_overlay(bs, base_bs);
+    if (!bottom_cow_node) {
+        error_setg(errp, "bottom node is not found, nothing to stream");
+        goto out;
+    }
+    /* Check for op blockers in the whole chain between bs and bottom */
+    for (iter = bs; iter && iter != bdrv_filtered_bs(bottom_cow_node);
+         iter = bdrv_filtered_bs(iter)) {
         if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) {
             goto out;
         }
diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index 104e3ce..d7638cd 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -368,8 +368,7 @@ class TestParallelOps(iotests.QMPTestCase):
         self.wait_until_completed(drive='commit-drive0')
 
     # In this case the base node of the stream job is the same as the
-    # top node of commit job. Since this results in the commit filter
-    # node being part of the stream chain, this is not allowed.
+    # top node of commit job.
     def test_overlapping_4(self):
         self.assert_no_active_block_jobs()
 
@@ -381,13 +380,13 @@ class TestParallelOps(iotests.QMPTestCase):
 
         # Stream from node2 into node4
         result = self.vm.qmp('block-stream', device='node4', base_node='node2', job_id='node4')
-        self.assert_qmp(result, 'error/desc',
-            "Cannot freeze 'backing' link to 'commit-filter'")
+        self.assert_qmp(result, 'return', {})
 
         result = self.vm.qmp('block-job-set-speed', device='drive0', speed=0)
         self.assert_qmp(result, 'return', {})
 
-        self.wait_until_completed()
+        self.vm.run_job(job='drive0', auto_dismiss=True)
+        self.vm.run_job(job='node4', auto_dismiss=True)
         self.assert_no_active_block_jobs()
 
     # In this case the base node of the stream job is the commit job's
-- 
1.8.3.1