[Qemu-block] [PATCH v9 05/11] block: allow block jobs in any arbitrary node

[Alberto Garcia]

Currently, block jobs can only be owned by root nodes. This patch
allows block jobs to be in any arbitrary node, by making the following
changes:

- Block jobs can now be identified by the node name of their
  BlockDriverState in addition to the device name. Since both device
  and node names live in the same namespace there's no ambiguity.

- The "device" parameter used by all commands that operate on block
  jobs can also be a node name now.

- The node name is used as a fallback to fill in the BlockJobInfo
  structure and all BLOCK_JOB_* events if there is no device name for
  that job.

Signed-off-by: Alberto Garcia <address@hidden>
---
 blockdev.c           | 18 ++++++++++--------
 blockjob.c           |  5 +++--
 docs/qmp-events.txt  |  8 ++++----
 qapi/block-core.json | 20 ++++++++++----------
 4 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index edbcc19..d1f5dfb 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3685,8 +3685,10 @@ void qmp_blockdev_mirror(const char *device, const char 
*target,
     aio_context_release(aio_context);
 }
 
-/* Get the block job for a given device name and acquire its AioContext */
-static BlockJob *find_block_job(const char *device, AioContext **aio_context,
+/* Get the block job for a given device or node name
+ * and acquire its AioContext */
+static BlockJob *find_block_job(const char *device_or_node,
+                                AioContext **aio_context,
                                 Error **errp)
 {
     BlockBackend *blk;
@@ -3694,18 +3696,18 @@ static BlockJob *find_block_job(const char *device, 
AioContext **aio_context,
 
     *aio_context = NULL;
 
-    blk = blk_by_name(device);
-    if (!blk) {
+    bs = bdrv_lookup_bs(device_or_node, device_or_node, errp);
+    if (!bs) {
         goto notfound;
     }
 
-    *aio_context = blk_get_aio_context(blk);
+    *aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(*aio_context);
 
-    if (!blk_is_available(blk)) {
+    blk = blk_by_name(device_or_node);
+    if (blk && !blk_is_available(blk)) {
         goto notfound;
     }
-    bs = blk_bs(blk);
 
     if (!bs->job) {
         goto notfound;
@@ -3715,7 +3717,7 @@ static BlockJob *find_block_job(const char *device, 
AioContext **aio_context,
 
 notfound:
     error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
-              "No active block job on device '%s'", device);
+              "No active block job on node '%s'", device_or_node);
     if (*aio_context) {
         aio_context_release(*aio_context);
         *aio_context = NULL;
diff --git a/blockjob.c b/blockjob.c
index 3557048..2ab4794 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -67,7 +67,8 @@ void *block_job_create(const BlockJobDriver *driver, 
BlockDriverState *bs,
     BlockJob *job;
 
     if (bs->job) {
-        error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
+        error_setg(errp, "Node '%s' is in use",
+                   bdrv_get_device_or_node_name(bs));
         return NULL;
     }
     bdrv_ref(bs);
@@ -78,7 +79,7 @@ void *block_job_create(const BlockJobDriver *driver, 
BlockDriverState *bs,
     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 
     job->driver        = driver;
-    job->id            = g_strdup(bdrv_get_device_name(bs));
+    job->id            = g_strdup(bdrv_get_device_or_node_name(bs));
     job->bs            = bs;
     job->cb            = cb;
     job->opaque        = opaque;
diff --git a/docs/qmp-events.txt b/docs/qmp-events.txt
index fa7574d..2d238c5 100644
--- a/docs/qmp-events.txt
+++ b/docs/qmp-events.txt
@@ -92,7 +92,7 @@ Data:
 
 - "type":     Job type (json-string; "stream" for image streaming
                                      "commit" for block commit)
-- "device":   Device name (json-string)
+- "device":   Device name, or node name if not present (json-string)
 - "len":      Maximum progress value (json-int)
 - "offset":   Current progress value (json-int)
               On success this is equal to len.
@@ -116,7 +116,7 @@ Data:
 
 - "type":     Job type (json-string; "stream" for image streaming
                                      "commit" for block commit)
-- "device":   Device name (json-string)
+- "device":   Device name, or node name if not present (json-string)
 - "len":      Maximum progress value (json-int)
 - "offset":   Current progress value (json-int)
               On success this is equal to len.
@@ -143,7 +143,7 @@ Emitted when a block job encounters an error.
 
 Data:
 
-- "device": device name (json-string)
+- "device": device name, or node name if not present (json-string)
 - "operation": I/O operation (json-string, "read" or "write")
 - "action": action that has been taken, it's one of the following 
(json-string):
     "ignore": error has been ignored, the job may fail later
@@ -167,7 +167,7 @@ Data:
 
 - "type":     Job type (json-string; "stream" for image streaming
                                      "commit" for block commit)
-- "device":   Device name (json-string)
+- "device":   Device name, or node name if not present (json-string)
 - "len":      Maximum progress value (json-int)
 - "offset":   Current progress value (json-int)
               On success this is equal to len.
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 1d09079..59107ed 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -713,7 +713,7 @@
 #
 # @type: the job type ('stream' for image streaming)
 #
-# @device: the block device name
+# @device: the block device name, or node name if not present
 #
 # @len: the maximum progress value
 #
@@ -1456,7 +1456,7 @@
 #
 # Throttling can be disabled by setting the speed to 0.
 #
-# @device: the device name
+# @device: the device or node name of the owner of the block job.
 #
 # @speed:  the maximum speed, in bytes per second, or 0 for unlimited.
 #          Defaults to 0.
@@ -1487,7 +1487,7 @@
 # operation can be started at a later time to finish copying all data from the
 # backing file.
 #
-# @device: the device name
+# @device: the device or node name of the owner of the block job.
 #
 # @force: #optional whether to allow cancellation of a paused job (default
 #         false).  Since 1.3.
@@ -1513,7 +1513,7 @@
 # the operation is actually paused.  Cancelling a paused job automatically
 # resumes it.
 #
-# @device: the device name
+# @device: the device or node name of the owner of the block job.
 #
 # Returns: Nothing on success
 #          If no background operation is active on this device, DeviceNotActive
@@ -1533,7 +1533,7 @@
 #
 # This command also clears the error status of the job.
 #
-# @device: the device name
+# @device: the device or node name of the owner of the block job.
 #
 # Returns: Nothing on success
 #          If no background operation is active on this device, DeviceNotActive
@@ -1559,7 +1559,7 @@
 #
 # A cancelled or paused job cannot be completed.
 #
-# @device: the device name
+# @device: the device or node name of the owner of the block job.
 #
 # Returns: Nothing on success
 #          If no background operation is active on this device, DeviceNotActive
@@ -2404,7 +2404,7 @@
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #
@@ -2435,7 +2435,7 @@
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #
@@ -2458,7 +2458,7 @@
 #
 # Emitted when a block job encounters an error
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @operation: I/O operation
 #
@@ -2478,7 +2478,7 @@
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #
-- 
2.8.0.rc3