diff mbox

[2/8] block: allow block jobs in any arbitrary node

Message ID ac711ac1d2b889a3de4a359eefa0d186447191e1.1429196435.git.berto@igalia.com
State New
Headers show

Commit Message

Alberto Garcia April 16, 2015, 3:12 p.m. UTC 
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 <berto@igalia.com>
---
 block/mirror.c            |  5 +++--
 blockdev.c                | 16 ++++++++--------
 blockjob.c                | 18 ++++++++++--------
 docs/qmp/qmp-events.txt   |  8 ++++----
 include/qapi/qmp/qerror.h |  3 ---
 qapi/block-core.json      | 20 ++++++++++----------
 6 files changed, 35 insertions(+), 35 deletions(-)

Comments

Max Reitz April 22, 2015, 5:15 p.m. UTC | #1 
On 16.04.2015 17:12, Alberto Garcia wrote:
> 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 <berto@igalia.com>
> ---
>   block/mirror.c            |  5 +++--
>   blockdev.c                | 16 ++++++++--------
>   blockjob.c                | 18 ++++++++++--------
>   docs/qmp/qmp-events.txt   |  8 ++++----
>   include/qapi/qmp/qerror.h |  3 ---
>   qapi/block-core.json      | 20 ++++++++++----------
>   6 files changed, 35 insertions(+), 35 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
Eric Blake April 22, 2015, 8:06 p.m. UTC | #2 
On 04/16/2015 09:12 AM, Alberto Garcia wrote:
> 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 <berto@igalia.com>
> ---
>  block/mirror.c            |  5 +++--
>  blockdev.c                | 16 ++++++++--------
>  blockjob.c                | 18 ++++++++++--------
>  docs/qmp/qmp-events.txt   |  8 ++++----
>  include/qapi/qmp/qerror.h |  3 ---
>  qapi/block-core.json      | 20 ++++++++++----------
>  6 files changed, 35 insertions(+), 35 deletions(-)
> 

> +++ b/docs/qmp/qmp-events.txt
> @@ -89,7 +89,7 @@ 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)

You used this wording for all the events...

> +++ b/qapi/block-core.json
> @@ -540,7 +540,7 @@
>  #
>  # @type: the job type ('stream' for image streaming)
>  #
> -# @device: the block device name
> +# @device: the block device name, or node name if not present
>  #

and again here,

>  # @len: the maximum progress value
>  #
> @@ -1065,7 +1065,7 @@
>  #
>  # 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.

but this wording is different.  I like it a bit better ("node name if
not present" feels like it could be a bit ambiguous as to what is not
present, and "device or node name" is shorter than "device name, or node
name if not present").

I'm not sure if it's worth changing, and I could live with the patch
as-is, so:

Reviewed-by: Eric Blake <eblake@redhat.com>
Alberto Garcia April 23, 2015, 9:04 a.m. UTC | #3 
On Wed 22 Apr 2015 10:06:15 PM CEST, Eric Blake wrote:

>> -- "device":   Device name (json-string)
>> +- "device":   Device name, or node name if not present (json-string)
>
> You used this wording for all the events...

>>  # 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.
>
> but this wording is different.  I like it a bit better ("node name if
> not present" feels like it could be a bit ambiguous as to what is not
> present, and "device or node name" is shorter than "device name, or
> node name if not present").

There's a reason for that.

I used "Device name, or node name if not present" in return types,
meaning that the field will always contain the device name first, and
fall back to the node name only if the device name is not present. I
think we should guarantee that the device name has precedence for
compatibility reasons, and I want to make that explicit in the
documentation.

I used "the device or node name of..." in command parameters, meaning
that both are accepted and equally valid, and that the user can choose
which one to pass.

Berto
diff mbox

Patch

diff --git a/block/mirror.c b/block/mirror.c
index 4056164..189e8f8 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -607,8 +607,9 @@  static void mirror_complete(BlockJob *job, Error **errp)
         return;
     }
     if (!s->synced) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_READY,
-                  bdrv_get_device_name(job->bs));
+        error_setg(errp,
+                   "The active block job for device '%s' cannot be completed",
+                   bdrv_get_device_name(job->bs));
         return;
     }
 
diff --git a/blockdev.c b/blockdev.c
index 567d5e3..677432f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2643,32 +2643,32 @@  out:
     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;
     BlockDriverState *bs;
 
-    blk = blk_by_name(device);
-    if (!blk) {
+    bs = bdrv_lookup_bs(device_or_node, device_or_node, errp);
+    if (!bs) {
         goto notfound;
     }
-    bs = blk_bs(blk);
 
     *aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(*aio_context);
 
     if (!bs->job) {
         aio_context_release(*aio_context);
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
+              "No active block job on node '%s'", device_or_node);
         goto notfound;
     }
 
     return bs->job;
 
 notfound:
-    error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
-              "No active block job on device '%s'", device);
     *aio_context = NULL;
     return NULL;
 }
diff --git a/blockjob.c b/blockjob.c
index 562362b..57cf0c3 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -52,7 +52,8 @@  void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     BlockJob *job;
 
     if (bs->job) {
-        error_set(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);
@@ -121,8 +122,9 @@  void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 void block_job_complete(BlockJob *job, Error **errp)
 {
     if (job->paused || job->cancelled || !job->driver->complete) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_READY,
-                  bdrv_get_device_name(job->bs));
+        error_setg(errp,
+                   "The active block job for node '%s' cannot be completed",
+                   bdrv_get_device_or_node_name(job->bs));
         return;
     }
 
@@ -268,7 +270,7 @@  BlockJobInfo *block_job_query(BlockJob *job)
 {
     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
-    info->device    = g_strdup(bdrv_get_device_name(job->bs));
+    info->device    = g_strdup(bdrv_get_device_or_node_name(job->bs));
     info->len       = job->len;
     info->busy      = job->busy;
     info->paused    = job->paused;
@@ -290,7 +292,7 @@  static void block_job_iostatus_set_err(BlockJob *job, int error)
 void block_job_event_cancelled(BlockJob *job)
 {
     qapi_event_send_block_job_cancelled(job->driver->job_type,
-                                        bdrv_get_device_name(job->bs),
+                                        bdrv_get_device_or_node_name(job->bs),
                                         job->len,
                                         job->offset,
                                         job->speed,
@@ -300,7 +302,7 @@  void block_job_event_cancelled(BlockJob *job)
 void block_job_event_completed(BlockJob *job, const char *msg)
 {
     qapi_event_send_block_job_completed(job->driver->job_type,
-                                        bdrv_get_device_name(job->bs),
+                                        bdrv_get_device_or_node_name(job->bs),
                                         job->len,
                                         job->offset,
                                         job->speed,
@@ -314,7 +316,7 @@  void block_job_event_ready(BlockJob *job)
     job->ready = true;
 
     qapi_event_send_block_job_ready(job->driver->job_type,
-                                    bdrv_get_device_name(job->bs),
+                                    bdrv_get_device_or_node_name(job->bs),
                                     job->len,
                                     job->offset,
                                     job->speed, &error_abort);
@@ -343,7 +345,7 @@  BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
     default:
         abort();
     }
-    qapi_event_send_block_job_error(bdrv_get_device_name(job->bs),
+    qapi_event_send_block_job_error(bdrv_get_device_or_node_name(job->bs),
                                     is_read ? IO_OPERATION_TYPE_READ :
                                     IO_OPERATION_TYPE_WRITE,
                                     action, &error_abort);
diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt
index b19e490..db90c61 100644
--- a/docs/qmp/qmp-events.txt
+++ b/docs/qmp/qmp-events.txt
@@ -89,7 +89,7 @@  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.
@@ -113,7 +113,7 @@  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.
@@ -140,7 +140,7 @@  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
@@ -164,7 +164,7 @@  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/include/qapi/qmp/qerror.h b/include/qapi/qmp/qerror.h
index e567339..4ba442e 100644
--- a/include/qapi/qmp/qerror.h
+++ b/include/qapi/qmp/qerror.h
@@ -37,9 +37,6 @@  void qerror_report_err(Error *err);
 #define QERR_BASE_NOT_FOUND \
     ERROR_CLASS_GENERIC_ERROR, "Base '%s' not found"
 
-#define QERR_BLOCK_JOB_NOT_READY \
-    ERROR_CLASS_GENERIC_ERROR, "The active block job for device '%s' cannot be completed"
-
 #define QERR_BUS_NO_HOTPLUG \
     ERROR_CLASS_GENERIC_ERROR, "Bus '%s' does not support hotplugging"
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 21e6cb5..5126ae0 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -540,7 +540,7 @@ 
 #
 # @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
 #
@@ -1065,7 +1065,7 @@ 
 #
 # 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.
@@ -1096,7 +1096,7 @@ 
 # 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.
@@ -1122,7 +1122,7 @@ 
 # 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
@@ -1142,7 +1142,7 @@ 
 #
 # 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
@@ -1168,7 +1168,7 @@ 
 #
 # 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
@@ -1821,7 +1821,7 @@ 
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #
@@ -1852,7 +1852,7 @@ 
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #
@@ -1875,7 +1875,7 @@ 
 #
 # Emitted when a block job encounters an error
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @operation: I/O operation
 #
@@ -1895,7 +1895,7 @@ 
 #
 # @type: job type
 #
-# @device: device name
+# @device: device name, or node name if not present
 #
 # @len: maximum progress value
 #