block: use aio_bh_schedule_oneshot

[qemu.git] / blockjob.c

diff --git a/blockjob.c b/blockjob.c
index 62bb9066349345f05b764a1fd004f03dbaa84589..43fecbe13ee4cb0c3314ca7a9d992b12ff208468 100644 (file)
--- a/blockjob.c
+++ b/blockjob.c
@@ -23,30 +23,134 @@
  * THE SOFTWARE.
  */
 
  * THE SOFTWARE.
  */
 

-#include "config-host.h"
+#include "qemu/osdep.h"

 #include "qemu-common.h"
 #include "trace.h"
 #include "block/block.h"
 #include "block/blockjob.h"
 #include "block/block_int.h"
 #include "qemu-common.h"
 #include "trace.h"
 #include "block/block.h"
 #include "block/blockjob.h"
 #include "block/block_int.h"

+#include "sysemu/block-backend.h"

 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qjson.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qjson.h"

-#include "block/coroutine.h"
+#include "qemu/coroutine.h"
+#include "qemu/id.h"

 #include "qmp-commands.h"
 #include "qemu/timer.h"
 #include "qapi-event.h"
 
 #include "qmp-commands.h"
 #include "qemu/timer.h"
 #include "qapi-event.h"
 

-void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
-                       int64_t speed, BlockCompletionFunc *cb,
-                       void *opaque, Error **errp)
+/* Transactional group of block jobs */
+struct BlockJobTxn {
+
+    /* Is this txn being cancelled? */
+    bool aborting;
+
+    /* List of jobs */
+    QLIST_HEAD(, BlockJob) jobs;
+
+    /* Reference count */
+    int refcnt;
+};
+
+static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
+
+BlockJob *block_job_next(BlockJob *job)
+{
+    if (!job) {
+        return QLIST_FIRST(&block_jobs);
+    }
+    return QLIST_NEXT(job, job_list);
+}
+
+BlockJob *block_job_get(const char *id)
+{
+    BlockJob *job;
+
+    QLIST_FOREACH(job, &block_jobs, job_list) {
+        if (!strcmp(id, job->id)) {
+            return job;
+        }
+    }
+
+    return NULL;
+}
+
+/* Normally the job runs in its BlockBackend's AioContext.  The exception is
+ * block_job_defer_to_main_loop() where it runs in the QEMU main loop.  Code
+ * that supports both cases uses this helper function.
+ */
+static AioContext *block_job_get_aio_context(BlockJob *job)
+{
+    return job->deferred_to_main_loop ?
+           qemu_get_aio_context() :
+           blk_get_aio_context(job->blk);
+}
+
+static void block_job_attached_aio_context(AioContext *new_context,
+                                           void *opaque)
+{
+    BlockJob *job = opaque;
+
+    if (job->driver->attached_aio_context) {
+        job->driver->attached_aio_context(job, new_context);
+    }
+
+    block_job_resume(job);
+}
+
+static void block_job_detach_aio_context(void *opaque)
+{
+    BlockJob *job = opaque;
+
+    /* In case the job terminates during aio_poll()... */
+    block_job_ref(job);
+
+    block_job_pause(job);
+
+    if (!job->paused) {
+        /* If job is !job->busy this kicks it into the next pause point. */
+        block_job_enter(job);
+    }
+    while (!job->paused && !job->completed) {
+        aio_poll(block_job_get_aio_context(job), true);
+    }
+
+    block_job_unref(job);
+}
+
+void *block_job_create(const char *job_id, const BlockJobDriver *driver,
+                       BlockDriverState *bs, int64_t speed,
+                       BlockCompletionFunc *cb, void *opaque, Error **errp)

 {
 {

+    BlockBackend *blk;

     BlockJob *job;
 
     BlockJob *job;
 

+    assert(cb);

     if (bs->job) {
         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
         return NULL;
     }
     if (bs->job) {
         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
         return NULL;
     }

-    bdrv_ref(bs);
+
+    if (job_id == NULL) {
+        job_id = bdrv_get_device_name(bs);
+        if (!*job_id) {
+            error_setg(errp, "An explicit job ID is required for this node");
+            return NULL;
+        }
+    }
+
+    if (!id_wellformed(job_id)) {
+        error_setg(errp, "Invalid job ID '%s'", job_id);
+        return NULL;
+    }
+
+    if (block_job_get(job_id)) {
+        error_setg(errp, "Job ID '%s' already in use", job_id);
+        return NULL;
+    }
+
+    blk = blk_new();
+    blk_insert_bs(blk, bs);
+

     job = g_malloc0(driver->instance_size);
     error_setg(&job->blocker, "block device is in use by block job: %s",
                BlockJobType_lookup[driver->job_type]);
     job = g_malloc0(driver->instance_size);
     error_setg(&job->blocker, "block device is in use by block job: %s",
                BlockJobType_lookup[driver->job_type]);


@@ -54,19 +158,26 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 
     job->driver        = driver;
     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 
     job->driver        = driver;

-    job->bs            = bs;
+    job->id            = g_strdup(job_id);
+    job->blk           = blk;

     job->cb            = cb;
     job->opaque        = opaque;
     job->busy          = true;
     job->cb            = cb;
     job->opaque        = opaque;
     job->busy          = true;

+    job->refcnt        = 1;

     bs->job = job;
 
     bs->job = job;
 

+    QLIST_INSERT_HEAD(&block_jobs, job, job_list);
+
+    blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
+                                 block_job_detach_aio_context, job);
+

     /* Only set speed when necessary to avoid NotSupported error */
     if (speed != 0) {
         Error *local_err = NULL;
 
         block_job_set_speed(job, speed, &local_err);
         if (local_err) {
     /* Only set speed when necessary to avoid NotSupported error */
     if (speed != 0) {
         Error *local_err = NULL;
 
         block_job_set_speed(job, speed, &local_err);
         if (local_err) {

-            block_job_release(bs);
+            block_job_unref(job);

             error_propagate(errp, local_err);
             return NULL;
         }
             error_propagate(errp, local_err);
             return NULL;
         }


@@ -74,23 +185,121 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     return job;
 }
 
     return job;
 }
 

-void block_job_release(BlockDriverState *bs)
+void block_job_ref(BlockJob *job)

 {
 {

-    BlockJob *job = bs->job;
+    ++job->refcnt;
+}

 
 

-    bs->job = NULL;
-    bdrv_op_unblock_all(bs, job->blocker);
-    error_free(job->blocker);
-    g_free(job);
+void block_job_unref(BlockJob *job)
+{
+    if (--job->refcnt == 0) {
+        BlockDriverState *bs = blk_bs(job->blk);
+        bs->job = NULL;
+        bdrv_op_unblock_all(bs, job->blocker);
+        blk_remove_aio_context_notifier(job->blk,
+                                        block_job_attached_aio_context,
+                                        block_job_detach_aio_context, job);
+        blk_unref(job->blk);
+        error_free(job->blocker);
+        g_free(job->id);
+        QLIST_REMOVE(job, job_list);
+        g_free(job);
+    }

 }
 
 }
 

-void block_job_completed(BlockJob *job, int ret)
+static void block_job_completed_single(BlockJob *job)
+{
+    if (!job->ret) {
+        if (job->driver->commit) {
+            job->driver->commit(job);
+        }
+    } else {
+        if (job->driver->abort) {
+            job->driver->abort(job);
+        }
+    }
+    job->cb(job->opaque, job->ret);
+    if (job->txn) {
+        block_job_txn_unref(job->txn);
+    }
+    block_job_unref(job);
+}
+
+static void block_job_completed_txn_abort(BlockJob *job)
+{
+    AioContext *ctx;
+    BlockJobTxn *txn = job->txn;
+    BlockJob *other_job, *next;
+
+    if (txn->aborting) {
+        /*
+         * We are cancelled by another job, which will handle everything.
+         */
+        return;
+    }
+    txn->aborting = true;
+    /* We are the first failed job. Cancel other jobs. */
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        ctx = blk_get_aio_context(other_job->blk);
+        aio_context_acquire(ctx);
+    }
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        if (other_job == job || other_job->completed) {
+            /* Other jobs are "effectively" cancelled by us, set the status for
+             * them; this job, however, may or may not be cancelled, depending
+             * on the caller, so leave it. */
+            if (other_job != job) {
+                other_job->cancelled = true;
+            }
+            continue;
+        }
+        block_job_cancel_sync(other_job);
+        assert(other_job->completed);
+    }
+    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+        ctx = blk_get_aio_context(other_job->blk);
+        block_job_completed_single(other_job);
+        aio_context_release(ctx);
+    }
+}
+
+static void block_job_completed_txn_success(BlockJob *job)

 {
 {

-    BlockDriverState *bs = job->bs;
+    AioContext *ctx;
+    BlockJobTxn *txn = job->txn;
+    BlockJob *other_job, *next;
+    /*
+     * Successful completion, see if there are other running jobs in this
+     * txn.
+     */
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        if (!other_job->completed) {
+            return;
+        }
+    }
+    /* We are the last completed job, commit the transaction. */
+    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+        ctx = blk_get_aio_context(other_job->blk);
+        aio_context_acquire(ctx);
+        assert(other_job->ret == 0);
+        block_job_completed_single(other_job);
+        aio_context_release(ctx);
+    }
+}

 
 

-    assert(bs->job == job);
-    job->cb(job->opaque, ret);
-    block_job_release(bs);
+void block_job_completed(BlockJob *job, int ret)
+{
+    assert(blk_bs(job->blk)->job == job);
+    assert(!job->completed);
+    job->completed = true;
+    job->ret = ret;
+    if (!job->txn) {
+        block_job_completed_single(job);
+    } else if (ret < 0 || block_job_is_cancelled(job)) {
+        block_job_completed_txn_abort(job);
+    } else {
+        block_job_completed_txn_success(job);
+    }

 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)


@@ -113,8 +322,8 @@ 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) {
 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,
-                   bdrv_get_device_name(job->bs));
+        error_setg(errp, "The active block job '%s' cannot be completed",
+                   job->id);

         return;
     }
 
         return;
     }
 


@@ -126,11 +335,37 @@ void block_job_pause(BlockJob *job)
     job->pause_count++;
 }
 
     job->pause_count++;
 }
 

-bool block_job_is_paused(BlockJob *job)
+static bool block_job_should_pause(BlockJob *job)

 {
     return job->pause_count > 0;
 }
 
 {
     return job->pause_count > 0;
 }
 

+void coroutine_fn block_job_pause_point(BlockJob *job)
+{
+    if (!block_job_should_pause(job)) {
+        return;
+    }
+    if (block_job_is_cancelled(job)) {
+        return;
+    }
+
+    if (job->driver->pause) {
+        job->driver->pause(job);
+    }
+
+    if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
+        job->paused = true;
+        job->busy = false;
+        qemu_coroutine_yield(); /* wait for block_job_resume() */
+        job->busy = true;
+        job->paused = false;
+    }
+
+    if (job->driver->resume) {
+        job->driver->resume(job);
+    }
+}
+

 void block_job_resume(BlockJob *job)
 {
     assert(job->pause_count > 0);
 void block_job_resume(BlockJob *job)
 {
     assert(job->pause_count > 0);


@@ -143,15 +378,15 @@ void block_job_resume(BlockJob *job)
 
 void block_job_enter(BlockJob *job)
 {
 
 void block_job_enter(BlockJob *job)
 {

-    block_job_iostatus_reset(job);

     if (job->co && !job->busy) {
     if (job->co && !job->busy) {

-        qemu_coroutine_enter(job->co, NULL);
+        qemu_coroutine_enter(job->co);

     }
 }
 
 void block_job_cancel(BlockJob *job)
 {
     job->cancelled = true;
     }
 }
 
 void block_job_cancel(BlockJob *job)
 {
     job->cancelled = true;

+    block_job_iostatus_reset(job);

     block_job_enter(job);
 }
 
     block_job_enter(job);
 }
 


@@ -168,51 +403,28 @@ void block_job_iostatus_reset(BlockJob *job)
     }
 }
 
     }
 }
 

-struct BlockFinishData {
-    BlockJob *job;
-    BlockCompletionFunc *cb;
-    void *opaque;
-    bool cancelled;
-    int ret;
-};
-
-static void block_job_finish_cb(void *opaque, int ret)
-{
-    struct BlockFinishData *data = opaque;
-
-    data->cancelled = block_job_is_cancelled(data->job);
-    data->ret = ret;
-    data->cb(data->opaque, ret);
-}
-

 static int block_job_finish_sync(BlockJob *job,
                                  void (*finish)(BlockJob *, Error **errp),
                                  Error **errp)
 {
 static int block_job_finish_sync(BlockJob *job,
                                  void (*finish)(BlockJob *, Error **errp),
                                  Error **errp)
 {

-    struct BlockFinishData data;
-    BlockDriverState *bs = job->bs;

     Error *local_err = NULL;
     Error *local_err = NULL;

+    int ret;

 
 

-    assert(bs->job == job);
+    assert(blk_bs(job->blk)->job == job);

 
 

-    /* Set up our own callback to store the result and chain to
-     * the original callback.
-     */
-    data.job = job;
-    data.cb = job->cb;
-    data.opaque = job->opaque;
-    data.ret = -EINPROGRESS;
-    job->cb = block_job_finish_cb;
-    job->opaque = &data;
+    block_job_ref(job);

     finish(job, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
     finish(job, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);

+        block_job_unref(job);

         return -EBUSY;
     }
         return -EBUSY;
     }

-    while (data.ret == -EINPROGRESS) {
-        aio_poll(bdrv_get_aio_context(bs), true);
+    while (!job->completed) {
+        aio_poll(block_job_get_aio_context(job), true);

     }
     }

-    return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
+    ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
+    block_job_unref(job);
+    return ret;

 }
 
 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
 }
 
 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be


@@ -228,6 +440,19 @@ int block_job_cancel_sync(BlockJob *job)
     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 }
 
     return block_job_finish_sync(job, &block_job_cancel_err, NULL);
 }
 

+void block_job_cancel_sync_all(void)
+{
+    BlockJob *job;
+    AioContext *aio_context;
+
+    while ((job = QLIST_FIRST(&block_jobs))) {
+        aio_context = blk_get_aio_context(job->blk);
+        aio_context_acquire(aio_context);
+        block_job_cancel_sync(job);
+        aio_context_release(aio_context);
+    }
+}
+

 int block_job_complete_sync(BlockJob *job, Error **errp)
 {
     return block_job_finish_sync(job, &block_job_complete, errp);
 int block_job_complete_sync(BlockJob *job, Error **errp)
 {
     return block_job_finish_sync(job, &block_job_complete, errp);


@@ -243,12 +468,12 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
     }
 
     job->busy = false;
     }
 
     job->busy = false;

-    if (block_job_is_paused(job)) {
-        qemu_coroutine_yield();
-    } else {
-        co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
+    if (!block_job_should_pause(job)) {
+        co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);

     }
     job->busy = true;
     }
     job->busy = true;

+
+    block_job_pause_point(job);

 }
 
 void block_job_yield(BlockJob *job)
 }
 
 void block_job_yield(BlockJob *job)


@@ -261,15 +486,19 @@ void block_job_yield(BlockJob *job)
     }
 
     job->busy = false;
     }
 
     job->busy = false;

-    qemu_coroutine_yield();
+    if (!block_job_should_pause(job)) {
+        qemu_coroutine_yield();
+    }

     job->busy = true;
     job->busy = true;

+
+    block_job_pause_point(job);

 }
 
 BlockJobInfo *block_job_query(BlockJob *job)
 {
     BlockJobInfo *info = g_new0(BlockJobInfo, 1);
     info->type      = g_strdup(BlockJobType_lookup[job->driver->job_type]);
 }
 
 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(job->id);

     info->len       = job->len;
     info->busy      = job->busy;
     info->paused    = job->pause_count > 0;
     info->len       = job->len;
     info->busy      = job->busy;
     info->paused    = job->pause_count > 0;


@@ -291,7 +520,7 @@ 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,
 void block_job_event_cancelled(BlockJob *job)
 {
     qapi_event_send_block_job_cancelled(job->driver->job_type,

-                                        bdrv_get_device_name(job->bs),
+                                        job->id,

                                         job->len,
                                         job->offset,
                                         job->speed,
                                         job->len,
                                         job->offset,
                                         job->speed,


@@ -301,7 +530,7 @@ 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,
 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),
+                                        job->id,

                                         job->len,
                                         job->offset,
                                         job->speed,
                                         job->len,
                                         job->offset,
                                         job->speed,


@@ -315,20 +544,20 @@ void block_job_event_ready(BlockJob *job)
     job->ready = true;
 
     qapi_event_send_block_job_ready(job->driver->job_type,
     job->ready = true;
 
     qapi_event_send_block_job_ready(job->driver->job_type,

-                                    bdrv_get_device_name(job->bs),
+                                    job->id,

                                     job->len,
                                     job->offset,
                                     job->speed, &error_abort);
 }
 
                                     job->len,
                                     job->offset,
                                     job->speed, &error_abort);
 }
 

-BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
-                                        BlockdevOnError on_err,
+BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,

                                         int is_read, int error)
 {
     BlockErrorAction action;
 
     switch (on_err) {
     case BLOCKDEV_ON_ERROR_ENOSPC:
                                         int is_read, int error)
 {
     BlockErrorAction action;
 
     switch (on_err) {
     case BLOCKDEV_ON_ERROR_ENOSPC:

+    case BLOCKDEV_ON_ERROR_AUTO:

         action = (error == ENOSPC) ?
                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
         break;
         action = (error == ENOSPC) ?
                  BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
         break;


@@ -344,7 +573,7 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
     default:
         abort();
     }
     default:
         abort();
     }

-    qapi_event_send_block_job_error(bdrv_get_device_name(job->bs),
+    qapi_event_send_block_job_error(job->id,

                                     is_read ? IO_OPERATION_TYPE_READ :
                                     IO_OPERATION_TYPE_WRITE,
                                     action, &error_abort);
                                     is_read ? IO_OPERATION_TYPE_READ :
                                     IO_OPERATION_TYPE_WRITE,
                                     action, &error_abort);


@@ -353,16 +582,12 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
         job->user_paused = true;
         block_job_pause(job);
         block_job_iostatus_set_err(job, error);
         job->user_paused = true;
         block_job_pause(job);
         block_job_iostatus_set_err(job, error);

-        if (bs != job->bs) {
-            bdrv_iostatus_set_err(bs, error);
-        }

     }
     return action;
 }
 
 typedef struct {
     BlockJob *job;
     }
     return action;
 }
 
 typedef struct {
     BlockJob *job;

-    QEMUBH *bh;

     AioContext *aio_context;
     BlockJobDeferToMainLoopFn *fn;
     void *opaque;
     AioContext *aio_context;
     BlockJobDeferToMainLoopFn *fn;
     void *opaque;


@@ -373,15 +598,14 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
     BlockJobDeferToMainLoopData *data = opaque;
     AioContext *aio_context;
 
     BlockJobDeferToMainLoopData *data = opaque;
     AioContext *aio_context;
 

-    qemu_bh_delete(data->bh);
-

     /* Prevent race with block_job_defer_to_main_loop() */
     aio_context_acquire(data->aio_context);
 
     /* Fetch BDS AioContext again, in case it has changed */
     /* Prevent race with block_job_defer_to_main_loop() */
     aio_context_acquire(data->aio_context);
 
     /* Fetch BDS AioContext again, in case it has changed */

-    aio_context = bdrv_get_aio_context(data->job->bs);
+    aio_context = blk_get_aio_context(data->job->blk);

     aio_context_acquire(aio_context);
 
     aio_context_acquire(aio_context);
 

+    data->job->deferred_to_main_loop = false;

     data->fn(data->job, data->opaque);
 
     aio_context_release(aio_context);
     data->fn(data->job, data->opaque);
 
     aio_context_release(aio_context);


@@ -397,10 +621,44 @@ void block_job_defer_to_main_loop(BlockJob *job,
 {
     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
     data->job = job;
 {
     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
     data->job = job;

-    data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
-    data->aio_context = bdrv_get_aio_context(job->bs);
+    data->aio_context = blk_get_aio_context(job->blk);

     data->fn = fn;
     data->opaque = opaque;
     data->fn = fn;
     data->opaque = opaque;

+    job->deferred_to_main_loop = true;
+
+    aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                            block_job_defer_to_main_loop_bh, data);
+}
+
+BlockJobTxn *block_job_txn_new(void)
+{
+    BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
+    QLIST_INIT(&txn->jobs);
+    txn->refcnt = 1;
+    return txn;
+}
+
+static void block_job_txn_ref(BlockJobTxn *txn)
+{
+    txn->refcnt++;
+}
+
+void block_job_txn_unref(BlockJobTxn *txn)
+{
+    if (txn && --txn->refcnt == 0) {
+        g_free(txn);
+    }
+}
+
+void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
+{
+    if (!txn) {
+        return;
+    }
+
+    assert(!job->txn);
+    job->txn = txn;

 
 

-    qemu_bh_schedule(data->bh);
+    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
+    block_job_txn_ref(txn);

 }
 }