[Qemu-devel] [PATCH v2 02/15] blockjob: Decouple the ID from the device name in the BlockJob struct

[Alberto Garcia]

Block jobs are identified by the name of the BlockBackend of the BDS
where the job was started.

We want block jobs to have unique, arbitrary identifiers that are not
tied to a block device, so this patch decouples the ID from the device
name in the BlockJob structure.

The ID is generated automatically for the moment, in later patches
we'll allow the user to set it.

Signed-off-by: Alberto Garcia <address@hidden>
---
 block/mirror.c            |  3 ++-
 blockjob.c                | 18 +++++++++++-------
 include/block/blockjob.h  | 12 ++++++++----
 include/qapi/qmp/qerror.h |  3 ---
 include/qemu/id.h         |  1 +
 util/id.c                 |  1 +
 6 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index a04ed9c..bcb1999 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -755,7 +755,8 @@ static void mirror_complete(BlockJob *job, Error **errp)
     target = blk_bs(s->target);
 
     if (!s->synced) {
-        error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
+        error_setg(errp, "The active block job '%s' cannot be completed",
+                   job->id);
         return;
     }
 
diff --git a/blockjob.c b/blockjob.c
index 90c4e26..8bcb5ea 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -33,6 +33,7 @@
 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qjson.h"
 #include "qemu/coroutine.h"
+#include "qemu/id.h"
 #include "qmp-commands.h"
 #include "qemu/timer.h"
 #include "qapi-event.h"
@@ -125,7 +126,8 @@ 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->device        = g_strdup(bdrv_get_device_name(bs));
+    job->id            = id_generate(ID_JOB);
     job->blk           = blk;
     job->cb            = cb;
     job->opaque        = opaque;
@@ -168,6 +170,7 @@ void block_job_unref(BlockJob *job)
                                         block_job_detach_aio_context, job);
         blk_unref(job->blk);
         error_free(job->blocker);
+        g_free(job->device);
         g_free(job->id);
         QLIST_REMOVE(job, job_list);
         g_free(job);
@@ -289,7 +292,8 @@ void block_job_set_speed(BlockJob *job, int64_t speed, 
Error **errp)
 void block_job_complete(BlockJob *job, Error **errp)
 {
     if (job->pause_count || job->cancelled || !job->driver->complete) {
-        error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
+        error_setg(errp, "The active block job '%s' cannot be completed",
+                   job->id);
         return;
     }
 
@@ -464,7 +468,7 @@ 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(job->id);
+    info->device    = g_strdup(job->device);
     info->len       = job->len;
     info->busy      = job->busy;
     info->paused    = job->pause_count > 0;
@@ -486,7 +490,7 @@ 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,
-                                        job->id,
+                                        job->device,
                                         job->len,
                                         job->offset,
                                         job->speed,
@@ -496,7 +500,7 @@ 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,
-                                        job->id,
+                                        job->device,
                                         job->len,
                                         job->offset,
                                         job->speed,
@@ -510,7 +514,7 @@ void block_job_event_ready(BlockJob *job)
     job->ready = true;
 
     qapi_event_send_block_job_ready(job->driver->job_type,
-                                    job->id,
+                                    job->device,
                                     job->len,
                                     job->offset,
                                     job->speed, &error_abort);
@@ -538,7 +542,7 @@ BlockErrorAction block_job_error_action(BlockJob *job, 
BlockdevOnError on_err,
     default:
         abort();
     }
-    qapi_event_send_block_job_error(job->id,
+    qapi_event_send_block_job_error(job->device,
                                     is_read ? IO_OPERATION_TYPE_READ :
                                     IO_OPERATION_TYPE_WRITE,
                                     action, &error_abort);
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 7dc720c..856486a 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -106,14 +106,18 @@ struct BlockJob {
     BlockBackend *blk;
 
     /**
-     * The ID of the block job. Currently the BlockBackend name of the BDS
-     * owning the job at the time when the job is started.
-     *
-     * TODO Decouple block job IDs from BlockBackend names
+     * The ID of the block job.
      */
     char *id;
 
     /**
+     * BlockBackend name of the BDS owning the job at the time when
+     * the job is started. For compatibility with clients that don't
+     * support the ID field.
+     */
+    char *device;
+
+    /**
      * The coroutine that executes the job.  If not NULL, it is
      * reentered when busy is false and the job is cancelled.
      */
diff --git a/include/qapi/qmp/qerror.h b/include/qapi/qmp/qerror.h
index d08652a..6586c9f 100644
--- a/include/qapi/qmp/qerror.h
+++ b/include/qapi/qmp/qerror.h
@@ -19,9 +19,6 @@
 #define QERR_BASE_NOT_FOUND \
     "Base '%s' not found"
 
-#define QERR_BLOCK_JOB_NOT_READY \
-    "The active block job for device '%s' cannot be completed"
-
 #define QERR_BUS_NO_HOTPLUG \
     "Bus '%s' does not support hotplugging"
 
diff --git a/include/qemu/id.h b/include/qemu/id.h
index 7d90335..c6c73ca 100644
--- a/include/qemu/id.h
+++ b/include/qemu/id.h
@@ -4,6 +4,7 @@
 typedef enum IdSubSystems {
     ID_QDEV,
     ID_BLOCK,
+    ID_JOB,
     ID_MAX      /* last element, used as array size */
 } IdSubSystems;
 
diff --git a/util/id.c b/util/id.c
index 6141352..eb5478b 100644
--- a/util/id.c
+++ b/util/id.c
@@ -34,6 +34,7 @@ bool id_wellformed(const char *id)
 static const char *const id_subsys_str[ID_MAX] = {
     [ID_QDEV]  = "qdev",
     [ID_BLOCK] = "block",
+    [ID_JOB]   = "job",
 };
 
 /*
-- 
2.8.1