]> Git Repo - qemu.git/blobdiff - blockjob.c
blockjob: introduce block_job_early_fail
[qemu.git] / blockjob.c
index 4aa14a4974b602d0063d97c5107b54470391ed59..5a722c36357a666410526cb1eaa816b836b86816 100644 (file)
@@ -25,7 +25,6 @@
 
 #include "qemu/osdep.h"
 #include "qemu-common.h"
-#include "trace.h"
 #include "block/block.h"
 #include "block/blockjob_int.h"
 #include "block/block_int.h"
@@ -56,6 +55,36 @@ struct BlockJobTxn {
 
 static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
 
+static char *child_job_get_parent_desc(BdrvChild *c)
+{
+    BlockJob *job = c->opaque;
+    return g_strdup_printf("%s job '%s'",
+                           BlockJobType_lookup[job->driver->job_type],
+                           job->id);
+}
+
+static const BdrvChildRole child_job = {
+    .get_parent_desc    = child_job_get_parent_desc,
+    .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) {
@@ -77,6 +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)
 {
@@ -116,19 +171,44 @@ static void block_job_detach_aio_context(void *opaque)
     block_job_unref(job);
 }
 
-void block_job_add_bdrv(BlockJob *job, BlockDriverState *bs)
+void block_job_remove_all_bdrv(BlockJob *job)
 {
-    job->nodes = g_slist_prepend(job->nodes, bs);
+    GSList *l;
+    for (l = job->nodes; l; l = l->next) {
+        BdrvChild *c = l->data;
+        bdrv_op_unblock_all(c->bs, job->blocker);
+        bdrv_root_unref_child(c);
+    }
+    g_slist_free(job->nodes);
+    job->nodes = NULL;
+}
+
+int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
+                       uint64_t perm, uint64_t shared_perm, Error **errp)
+{
+    BdrvChild *c;
+
+    c = bdrv_root_attach_child(bs, name, &child_job, perm, shared_perm,
+                               job, errp);
+    if (c == NULL) {
+        return -EPERM;
+    }
+
+    job->nodes = g_slist_prepend(job->nodes, c);
     bdrv_ref(bs);
     bdrv_op_block_all(bs, job->blocker);
+
+    return 0;
 }
 
 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
-                       BlockDriverState *bs, int64_t speed, int flags,
+                       BlockDriverState *bs, uint64_t perm,
+                       uint64_t shared_perm, int64_t speed, int flags,
                        BlockCompletionFunc *cb, void *opaque, Error **errp)
 {
     BlockBackend *blk;
     BlockJob *job;
+    int ret;
 
     if (bs->job) {
         error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
@@ -160,24 +240,32 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
         }
     }
 
-    blk = blk_new();
-    blk_insert_bs(blk, bs);
+    blk = blk_new(perm, shared_perm);
+    ret = blk_insert_bs(blk, bs, errp);
+    if (ret < 0) {
+        blk_unref(blk);
+        return NULL;
+    }
 
     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, bs);
-    bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
-
     job->driver        = driver;
     job->id            = g_strdup(job_id);
     job->blk           = blk;
     job->cb            = cb;
     job->opaque        = opaque;
-    job->busy          = true;
+    job->busy          = false;
+    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,
@@ -202,32 +290,38 @@ bool block_job_is_internal(BlockJob *job)
     return (job->id == NULL);
 }
 
-void block_job_ref(BlockJob *job)
+static bool block_job_started(BlockJob *job)
 {
-    ++job->refcnt;
+    return job->co;
 }
 
-void block_job_unref(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)
 {
-    if (--job->refcnt == 0) {
-        GSList *l;
-        BlockDriverState *bs = blk_bs(job->blk);
-        bs->job = NULL;
-        for (l = job->nodes; l; l = l->next) {
-            bs = l->data;
-            bdrv_op_unblock_all(bs, job->blocker);
-            bdrv_unref(bs);
-        }
-        g_slist_free(job->nodes);
-        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);
-    }
+    BlockJob *job = opaque;
+
+    assert(job && job->driver && job->driver->start);
+    block_job_pause_point(job);
+    job->driver->start(job);
+}
+
+void block_job_start(BlockJob *job)
+{
+    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_early_fail(BlockJob *job)
+{
+    block_job_unref(job);
 }
 
 static void block_job_completed_single(BlockJob *job)
@@ -241,21 +335,29 @@ static void block_job_completed_single(BlockJob *job)
             job->driver->abort(job);
         }
     }
+    if (job->driver->clean) {
+        job->driver->clean(job);
+    }
 
     if (job->cb) {
         job->cb(job->opaque, job->ret);
     }
-    if (block_job_is_cancelled(job)) {
-        block_job_event_cancelled(job);
-    } else {
-        const char *msg = NULL;
-        if (job->ret < 0) {
-            msg = strerror(-job->ret);
+
+    /* Emit events only if we actually started */
+    if (block_job_started(job)) {
+        if (block_job_is_cancelled(job)) {
+            block_job_event_cancelled(job);
+        } else {
+            const char *msg = NULL;
+            if (job->ret < 0) {
+                msg = strerror(-job->ret);
+            }
+            block_job_event_completed(job, msg);
         }
-        block_job_event_completed(job, msg);
     }
 
     if (job->txn) {
+        QLIST_REMOVE(job, txn_list);
         block_job_txn_unref(job->txn);
     }
     block_job_unref(job);
@@ -359,7 +461,8 @@ void block_job_complete(BlockJob *job, Error **errp)
 {
     /* Should not be reachable via external interface for internal jobs */
     assert(job->id);
-    if (job->pause_count || job->cancelled || !job->driver->complete) {
+    if (job->pause_count || job->cancelled ||
+        !block_job_started(job) || !job->driver->complete) {
         error_setg(errp, "The active block job '%s' cannot be completed",
                    job->id);
         return;
@@ -386,11 +489,13 @@ 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)
 {
+    assert(job && block_job_started(job));
+
     if (!block_job_should_pause(job)) {
         return;
     }
@@ -436,15 +541,19 @@ 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);
     }
 }
 
 void block_job_cancel(BlockJob *job)
 {
-    job->cancelled = true;
-    block_job_iostatus_reset(job);
-    block_job_enter(job);
+    if (block_job_started(job)) {
+        job->cancelled = true;
+        block_job_iostatus_reset(job);
+        block_job_enter(job);
+    } else {
+        block_job_completed(job, -ECANCELED);
+    }
 }
 
 bool block_job_is_cancelled(BlockJob *job)
@@ -455,9 +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,
@@ -686,12 +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);
 
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