blockjob: introduce block_job_early_fail

[qemu.git] / blockjob.c

diff --git a/blockjob.c b/blockjob.c
index 69126af97fe82e1cb4bd72a5a424fdddeb4287ce..5a722c36357a666410526cb1eaa816b836b86816 100644 (file)
--- a/blockjob.c
+++ b/blockjob.c
@@ -68,6 +68,23 @@ static const BdrvChildRole child_job = {
     .stay_at_node       = true,
 };
 
+static void block_job_drained_begin(void *opaque)
+{
+    BlockJob *job = opaque;
+    block_job_pause(job);
+}
+
+static void block_job_drained_end(void *opaque)
+{
+    BlockJob *job = opaque;
+    block_job_resume(job);
+}
+
+static const BlockDevOps block_job_dev_ops = {
+    .drained_begin = block_job_drained_begin,
+    .drained_end = block_job_drained_end,
+};
+
 BlockJob *block_job_next(BlockJob *job)
 {
     if (!job) {
@@ -89,6 +106,32 @@ BlockJob *block_job_get(const char *id)
     return NULL;
 }
 
+static void block_job_ref(BlockJob *job)
+{
+    ++job->refcnt;
+}
+
+static void block_job_attached_aio_context(AioContext *new_context,
+                                           void *opaque);
+static void block_job_detach_aio_context(void *opaque);
+
+static void block_job_unref(BlockJob *job)
+{
+    if (--job->refcnt == 0) {
+        BlockDriverState *bs = blk_bs(job->blk);
+        bs->job = NULL;
+        block_job_remove_all_bdrv(job);
+        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);
+    }
+}
+
 static void block_job_attached_aio_context(AioContext *new_context,
                                            void *opaque)
 {
@@ -205,11 +248,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     }
 
     job = g_malloc0(driver->instance_size);
-    error_setg(&job->blocker, "block device is in use by block job: %s",
-               BlockJobType_lookup[driver->job_type]);
-    block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
-    bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
-
     job->driver        = driver;
     job->id            = g_strdup(job_id);
     job->blk           = blk;
@@ -219,8 +257,15 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     job->paused        = true;
     job->pause_count   = 1;
     job->refcnt        = 1;
+
+    error_setg(&job->blocker, "block device is in use by block job: %s",
+               BlockJobType_lookup[driver->job_type]);
+    block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
     bs->job = job;
 
+    blk_set_dev_ops(blk, &block_job_dev_ops, job);
+    bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
+
     QLIST_INSERT_HEAD(&block_jobs, job, job_list);
 
     blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
@@ -250,38 +295,33 @@ static bool block_job_started(BlockJob *job)
     return job->co;
 }
 
-void block_job_start(BlockJob *job)
+/**
+ * All jobs must allow a pause point before entering their job proper. This
+ * ensures that jobs can be paused prior to being started, then resumed later.
+ */
+static void coroutine_fn block_job_co_entry(void *opaque)
 {
-    assert(job && !block_job_started(job) && job->paused &&
-           !job->busy && job->driver->start);
-    job->co = qemu_coroutine_create(job->driver->start, job);
-    if (--job->pause_count == 0) {
-        job->paused = false;
-        job->busy = true;
-        qemu_coroutine_enter(job->co);
-    }
+    BlockJob *job = opaque;
+
+    assert(job && job->driver && job->driver->start);
+    block_job_pause_point(job);
+    job->driver->start(job);
 }
 
-void block_job_ref(BlockJob *job)
+void block_job_start(BlockJob *job)
 {
-    ++job->refcnt;
+    assert(job && !block_job_started(job) && job->paused &&
+           job->driver && job->driver->start);
+    job->co = qemu_coroutine_create(block_job_co_entry, job);
+    job->pause_count--;
+    job->busy = true;
+    job->paused = false;
+    bdrv_coroutine_enter(blk_bs(job->blk), job->co);
 }
 
-void block_job_unref(BlockJob *job)
+void block_job_early_fail(BlockJob *job)
 {
-    if (--job->refcnt == 0) {
-        BlockDriverState *bs = blk_bs(job->blk);
-        bs->job = NULL;
-        block_job_remove_all_bdrv(job);
-        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);
-    }
+    block_job_unref(job);
 }
 
 static void block_job_completed_single(BlockJob *job)
@@ -449,7 +489,7 @@ static bool block_job_should_pause(BlockJob *job)
 
 bool block_job_user_paused(BlockJob *job)
 {
-    return job ? job->user_paused : 0;
+    return job->user_paused;
 }
 
 void coroutine_fn block_job_pause_point(BlockJob *job)
@@ -501,7 +541,7 @@ void block_job_user_resume(BlockJob *job)
 void block_job_enter(BlockJob *job)
 {
     if (job->co && !job->busy) {
-        qemu_coroutine_enter(job->co);
+        bdrv_coroutine_enter(blk_bs(job->blk), job->co);
     }
 }
 
@@ -524,9 +564,6 @@ bool block_job_is_cancelled(BlockJob *job)
 void block_job_iostatus_reset(BlockJob *job)
 {
     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
-    if (job->driver->iostatus_reset) {
-        job->driver->iostatus_reset(job);
-    }
 }
 
 static int block_job_finish_sync(BlockJob *job,
@@ -755,12 +792,16 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
 
     /* Fetch BDS AioContext again, in case it has changed */
     aio_context = blk_get_aio_context(data->job->blk);
-    aio_context_acquire(aio_context);
+    if (aio_context != data->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);
+    if (aio_context != data->aio_context) {
+        aio_context_release(aio_context);
+    }
 
     aio_context_release(data->aio_context);