Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- iscsi: Cap block count from GET LBA STATUS (CVE-2020-1711)
- AioContext fixes in QMP commands for backup and bitmaps
- iotests fixes

# gpg: Signature made Mon 27 Jan 2020 17:49:58 GMT
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  iscsi: Don't access non-existent scsi_lba_status_descriptor
  iscsi: Cap block count from GET LBA STATUS (CVE-2020-1711)
  block/backup: fix memory leak in bdrv_backup_top_append()
  iotests: Test handling of AioContexts with some blockdev actions
  blockdev: Return bs to the proper context on snapshot abort
  blockdev: Acquire AioContext on dirty bitmap functions
  block/backup-top: Don't acquire context while dropping top
  blockdev: honor bdrv_try_set_aio_context() context requirements
  blockdev: unify qmp_blockdev_backup and blockdev-backup transaction paths
  blockdev: unify qmp_drive_backup and drive-backup transaction paths
  blockdev: fix coding style issues in drive_backup_prepare
  iotests: Add more "skip_if_unsupported" statements to the python tests
  iotests.py: Let wait_migration wait even more

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

19 files changed, 510 insertions, 239 deletions

diff --git a/block/backup-top.c b/block/backup-top.c
index 818d3f2..9aed2eb 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -196,7 +196,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
     }
 
     top->total_sectors = source->total_sectors;
-    top->opaque = state = g_new0(BDRVBackupTopState, 1);
+    state = top->opaque;
 
     bdrv_ref(target);
     state->target = bdrv_attach_child(top, target, "target", &child_file, errp);
@@ -255,9 +255,6 @@ append_failed:
 void bdrv_backup_top_drop(BlockDriverState *bs)
 {
     BDRVBackupTopState *s = bs->opaque;
-    AioContext *aio_context = bdrv_get_aio_context(bs);
-
-    aio_context_acquire(aio_context);
 
     bdrv_drained_begin(bs);
 
@@ -271,6 +268,4 @@ void bdrv_backup_top_drop(BlockDriverState *bs)
     bdrv_drained_end(bs);
 
     bdrv_unref(bs);
-
-    aio_context_release(aio_context);
 }
diff --git a/block/backup.c b/block/backup.c
index cf62b1a..1383e21 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -135,8 +135,11 @@ static void backup_abort(Job *job)
 static void backup_clean(Job *job)
 {
     BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+    AioContext *aio_context = bdrv_get_aio_context(s->backup_top);
 
+    aio_context_acquire(aio_context);
     bdrv_backup_top_drop(s->backup_top);
+    aio_context_release(aio_context);
 }
 
 void backup_do_checkpoint(BlockJob *job, Error **errp)
diff --git a/block/iscsi.c b/block/iscsi.c
index 2aea7e3..c8feaa2 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -701,7 +701,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
     struct scsi_get_lba_status *lbas = NULL;
     struct scsi_lba_status_descriptor *lbasd = NULL;
     struct IscsiTask iTask;
-    uint64_t lba;
+    uint64_t lba, max_bytes;
     int ret;
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
@@ -721,6 +721,7 @@ static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
     }
 
     lba = offset / iscsilun->block_size;
+    max_bytes = (iscsilun->num_blocks - lba) * iscsilun->block_size;
 
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
@@ -752,7 +753,7 @@ retry:
     }
 
     lbas = scsi_datain_unmarshall(iTask.task);
-    if (lbas == NULL) {
+    if (lbas == NULL || lbas->num_descriptors == 0) {
         ret = -EIO;
         goto out_unlock;
     }
@@ -764,7 +765,7 @@ retry:
         goto out_unlock;
     }
 
-    *pnum = (int64_t) lbasd->num_blocks * iscsilun->block_size;
+    *pnum = MIN((int64_t) lbasd->num_blocks * iscsilun->block_size, max_bytes);
 
     if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
         lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
diff --git a/blockdev.c b/blockdev.c
index 8e029e9..4cd9a58 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1535,6 +1535,7 @@ static void external_snapshot_prepare(BlkActionState *common,
                              DO_UPCAST(ExternalSnapshotState, common, common);
     TransactionAction *action = common->action;
     AioContext *aio_context;
+    AioContext *old_context;
     int ret;
 
     /* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar
@@ -1675,7 +1676,16 @@ static void external_snapshot_prepare(BlkActionState *common,
         goto out;
     }
 
+    /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
+    old_context = bdrv_get_aio_context(state->new_bs);
+    aio_context_release(aio_context);
+    aio_context_acquire(old_context);
+
     ret = bdrv_try_set_aio_context(state->new_bs, aio_context, errp);
+
+    aio_context_release(old_context);
+    aio_context_acquire(aio_context);
+
     if (ret < 0) {
         goto out;
     }
@@ -1721,6 +1731,8 @@ static void external_snapshot_abort(BlkActionState *common)
     if (state->new_bs) {
         if (state->overlay_appended) {
             AioContext *aio_context;
+            AioContext *tmp_context;
+            int ret;
 
             aio_context = bdrv_get_aio_context(state->old_bs);
             aio_context_acquire(aio_context);
@@ -1728,6 +1740,25 @@ static void external_snapshot_abort(BlkActionState *common)
             bdrv_ref(state->old_bs);   /* we can't let bdrv_set_backind_hd()
                                           close state->old_bs; we need it */
             bdrv_set_backing_hd(state->new_bs, NULL, &error_abort);
+
+            /*
+             * The call to bdrv_set_backing_hd() above returns state->old_bs to
+             * the main AioContext. As we're still going to be using it, return
+             * it to the AioContext it was before.
+             */
+            tmp_context = bdrv_get_aio_context(state->old_bs);
+            if (aio_context != tmp_context) {
+                aio_context_release(aio_context);
+                aio_context_acquire(tmp_context);
+
+                ret = bdrv_try_set_aio_context(state->old_bs,
+                                               aio_context, NULL);
+                assert(ret == 0);
+
+                aio_context_release(tmp_context);
+                aio_context_acquire(aio_context);
+            }
+
             bdrv_replace_node(state->new_bs, state->old_bs, &error_abort);
             bdrv_unref(state->old_bs); /* bdrv_replace_node() ref'ed old_bs */
 
@@ -1761,39 +1792,145 @@ typedef struct DriveBackupState {
     BlockJob *job;
 } DriveBackupState;
 
-static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
-                            Error **errp);
+static BlockJob *do_backup_common(BackupCommon *backup,
+                                  BlockDriverState *bs,
+                                  BlockDriverState *target_bs,
+                                  AioContext *aio_context,
+                                  JobTxn *txn, Error **errp);
 
 static void drive_backup_prepare(BlkActionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
-    BlockDriverState *bs;
     DriveBackup *backup;
+    BlockDriverState *bs;
+    BlockDriverState *target_bs;
+    BlockDriverState *source = NULL;
     AioContext *aio_context;
+    AioContext *old_context;
+    QDict *options;
     Error *local_err = NULL;
+    int flags;
+    int64_t size;
+    bool set_backing_hd = false;
+    int ret;
 
     assert(common->action->type == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
     backup = common->action->u.drive_backup.data;
 
+    if (!backup->has_mode) {
+        backup->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+    }
+
     bs = bdrv_lookup_bs(backup->device, backup->device, errp);
     if (!bs) {
         return;
     }
 
+    if (!bs->drv) {
+        error_setg(errp, "Device has no medium");
+        return;
+    }
+
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
     /* Paired with .clean() */
     bdrv_drained_begin(bs);
 
-    state->bs = bs;
+    if (!backup->has_format) {
+        backup->format = backup->mode == NEW_IMAGE_MODE_EXISTING ?
+                         NULL : (char *) bs->drv->format_name;
+    }
+
+    /* Early check to avoid creating target */
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
+        goto out;
+    }
+
+    flags = bs->open_flags | BDRV_O_RDWR;
+
+    /*
+     * See if we have a backing HD we can use to create our new image
+     * on top of.
+     */
+    if (backup->sync == MIRROR_SYNC_MODE_TOP) {
+        source = backing_bs(bs);
+        if (!source) {
+            backup->sync = MIRROR_SYNC_MODE_FULL;
+        }
+    }
+    if (backup->sync == MIRROR_SYNC_MODE_NONE) {
+        source = bs;
+        flags |= BDRV_O_NO_BACKING;
+        set_backing_hd = true;
+    }
+
+    size = bdrv_getlength(bs);
+    if (size < 0) {
+        error_setg_errno(errp, -size, "bdrv_getlength failed");
+        goto out;
+    }
+
+    if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
+        assert(backup->format);
+        if (source) {
+            bdrv_refresh_filename(source);
+            bdrv_img_create(backup->target, backup->format, source->filename,
+                            source->drv->format_name, NULL,
+                            size, flags, false, &local_err);
+        } else {
+            bdrv_img_create(backup->target, backup->format, NULL, NULL, NULL,
+                            size, flags, false, &local_err);
+        }
+    }
 
-    state->job = do_drive_backup(backup, common->block_job_txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto out;
     }
 
+    options = qdict_new();
+    qdict_put_str(options, "discard", "unmap");
+    qdict_put_str(options, "detect-zeroes", "unmap");
+    if (backup->format) {
+        qdict_put_str(options, "driver", backup->format);
+    }
+
+    target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
+    if (!target_bs) {
+        goto out;
+    }
+
+    /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
+    old_context = bdrv_get_aio_context(target_bs);
+    aio_context_release(aio_context);
+    aio_context_acquire(old_context);
+
+    ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
+    if (ret < 0) {
+        bdrv_unref(target_bs);
+        aio_context_release(old_context);
+        return;
+    }
+
+    aio_context_release(old_context);
+    aio_context_acquire(aio_context);
+
+    if (set_backing_hd) {
+        bdrv_set_backing_hd(target_bs, source, &local_err);
+        if (local_err) {
+            goto unref;
+        }
+    }
+
+    state->bs = bs;
+
+    state->job = do_backup_common(qapi_DriveBackup_base(backup),
+                                  bs, target_bs, aio_context,
+                                  common->block_job_txn, errp);
+
+unref:
+    bdrv_unref(target_bs);
 out:
     aio_context_release(aio_context);
 }
@@ -1851,16 +1988,15 @@ typedef struct BlockdevBackupState {
     BlockJob *job;
 } BlockdevBackupState;
 
-static BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
-                                    Error **errp);
-
 static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockdevBackup *backup;
-    BlockDriverState *bs, *target;
+    BlockDriverState *bs;
+    BlockDriverState *target_bs;
     AioContext *aio_context;
-    Error *local_err = NULL;
+    AioContext *old_context;
+    int ret;
 
     assert(common->action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
     backup = common->action->u.blockdev_backup.data;
@@ -1870,25 +2006,33 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
         return;
     }
 
-    target = bdrv_lookup_bs(backup->target, backup->target, errp);
-    if (!target) {
+    target_bs = bdrv_lookup_bs(backup->target, backup->target, errp);
+    if (!target_bs) {
         return;
     }
 
+    /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
     aio_context = bdrv_get_aio_context(bs);
+    old_context = bdrv_get_aio_context(target_bs);
+    aio_context_acquire(old_context);
+
+    ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
+    if (ret < 0) {
+        aio_context_release(old_context);
+        return;
+    }
+
+    aio_context_release(old_context);
     aio_context_acquire(aio_context);
     state->bs = bs;
 
     /* Paired with .clean() */
     bdrv_drained_begin(state->bs);
 
-    state->job = do_blockdev_backup(backup, common->block_job_txn, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        goto out;
-    }
+    state->job = do_backup_common(qapi_BlockdevBackup_base(backup),
+                                  bs, target_bs, aio_context,
+                                  common->block_job_txn, errp);
 
-out:
     aio_context_release(aio_context);
 }
 
@@ -2861,6 +3005,7 @@ void qmp_block_dirty_bitmap_add(const char *node, const char *name,
 {
     BlockDriverState *bs;
     BdrvDirtyBitmap *bitmap;
+    AioContext *aio_context;
 
     if (!name || name[0] == '\0') {
         error_setg(errp, "Bitmap name cannot be empty");
@@ -2872,11 +3017,14 @@ void qmp_block_dirty_bitmap_add(const char *node, const char *name,
         return;
     }
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
     if (has_granularity) {
         if (granularity < 512 || !is_power_of_2(granularity)) {
             error_setg(errp, "Granularity must be power of 2 "
                              "and at least 512");
-            return;
+            goto out;
         }
     } else {
         /* Default to cluster size, if available: */
@@ -2894,12 +3042,12 @@ void qmp_block_dirty_bitmap_add(const char *node, const char *name,
     if (persistent &&
         !bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp))
     {
-        return;
+        goto out;
     }
 
     bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
     if (bitmap == NULL) {
-        return;
+        goto out;
     }
 
     if (disabled) {
@@ -2907,6 +3055,9 @@ void qmp_block_dirty_bitmap_add(const char *node, const char *name,
     }
 
     bdrv_dirty_bitmap_set_persistence(bitmap, persistent);
+
+out:
+    aio_context_release(aio_context);
 }
 
 static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
@@ -2915,21 +3066,27 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
 {
     BlockDriverState *bs;
     BdrvDirtyBitmap *bitmap;
+    AioContext *aio_context;
 
     bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
     if (!bitmap || !bs) {
         return NULL;
     }
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
     if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY | BDRV_BITMAP_RO,
                                 errp)) {
+        aio_context_release(aio_context);
         return NULL;
     }
 
     if (bdrv_dirty_bitmap_get_persistence(bitmap) &&
         bdrv_remove_persistent_dirty_bitmap(bs, name, errp) < 0)
     {
-            return NULL;
+        aio_context_release(aio_context);
+        return NULL;
     }
 
     if (release) {
@@ -2940,6 +3097,7 @@ static BdrvDirtyBitmap *do_block_dirty_bitmap_remove(
         *bitmap_bs = bs;
     }
 
+    aio_context_release(aio_context);
     return release ? NULL : bitmap;
 }
 
@@ -3479,7 +3637,6 @@ static BlockJob *do_backup_common(BackupCommon *backup,
     BlockJob *job = NULL;
     BdrvDirtyBitmap *bmap = NULL;
     int job_flags = JOB_DEFAULT;
-    int ret;
 
     if (!backup->has_speed) {
         backup->speed = 0;
@@ -3503,11 +3660,6 @@ static BlockJob *do_backup_common(BackupCommon *backup,
         backup->compress = false;
     }
 
-    ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
-    if (ret < 0) {
-        return NULL;
-    }
-
     if ((backup->sync == MIRROR_SYNC_MODE_BITMAP) ||
         (backup->sync == MIRROR_SYNC_MODE_INCREMENTAL)) {
         /* done before desugaring 'incremental' to print the right message */
@@ -3587,124 +3739,13 @@ static BlockJob *do_backup_common(BackupCommon *backup,
     return job;
 }
 
-static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
-                                 Error **errp)
-{
-    BlockDriverState *bs;
-    BlockDriverState *target_bs;
-    BlockDriverState *source = NULL;
-    BlockJob *job = NULL;
-    AioContext *aio_context;
-    QDict *options;
-    Error *local_err = NULL;
-    int flags;
-    int64_t size;
-    bool set_backing_hd = false;
-
-    if (!backup->has_mode) {
-        backup->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
-    }
-
-    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
-    if (!bs) {
-        return NULL;
-    }
-
-    if (!bs->drv) {
-        error_setg(errp, "Device has no medium");
-        return NULL;
-    }
-
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
-
-    if (!backup->has_format) {
-        backup->format = backup->mode == NEW_IMAGE_MODE_EXISTING ?
-                         NULL : (char*) bs->drv->format_name;
-    }
-
-    /* Early check to avoid creating target */
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
-        goto out;
-    }
-
-    flags = bs->open_flags | BDRV_O_RDWR;
-
-    /* See if we have a backing HD we can use to create our new image
-     * on top of. */
-    if (backup->sync == MIRROR_SYNC_MODE_TOP) {
-        source = backing_bs(bs);
-        if (!source) {
-            backup->sync = MIRROR_SYNC_MODE_FULL;
-        }
-    }
-    if (backup->sync == MIRROR_SYNC_MODE_NONE) {
-        source = bs;
-        flags |= BDRV_O_NO_BACKING;
-        set_backing_hd = true;
-    }
-
-    size = bdrv_getlength(bs);
-    if (size < 0) {
-        error_setg_errno(errp, -size, "bdrv_getlength failed");
-        goto out;
-    }
-
-    if (backup->mode != NEW_IMAGE_MODE_EXISTING) {
-        assert(backup->format);
-        if (source) {
-            bdrv_refresh_filename(source);
-            bdrv_img_create(backup->target, backup->format, source->filename,
-                            source->drv->format_name, NULL,
-                            size, flags, false, &local_err);
-        } else {
-            bdrv_img_create(backup->target, backup->format, NULL, NULL, NULL,
-                            size, flags, false, &local_err);
-        }
-    }
-
-    if (local_err) {
-        error_propagate(errp, local_err);
-        goto out;
-    }
-
-    options = qdict_new();
-    qdict_put_str(options, "discard", "unmap");
-    qdict_put_str(options, "detect-zeroes", "unmap");
-    if (backup->format) {
-        qdict_put_str(options, "driver", backup->format);
-    }
-
-    target_bs = bdrv_open(backup->target, NULL, options, flags, errp);
-    if (!target_bs) {
-        goto out;
-    }
-
-    if (set_backing_hd) {
-        bdrv_set_backing_hd(target_bs, source, &local_err);
-        if (local_err) {
-            goto unref;
-        }
-    }
-
-    job = do_backup_common(qapi_DriveBackup_base(backup),
-                           bs, target_bs, aio_context, txn, errp);
-
-unref:
-    bdrv_unref(target_bs);
-out:
-    aio_context_release(aio_context);
-    return job;
-}
-
-void qmp_drive_backup(DriveBackup *arg, Error **errp)
+void qmp_drive_backup(DriveBackup *backup, Error **errp)
 {
-
-    BlockJob *job;
-    job = do_drive_backup(arg, NULL, errp);
-    if (job) {
-        job_start(&job->job);
-    }
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_DRIVE_BACKUP,
+        .u.drive_backup.data = backup,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
@@ -3717,41 +3758,13 @@ XDbgBlockGraph *qmp_x_debug_query_block_graph(Error **errp)
     return bdrv_get_xdbg_block_graph(errp);
 }
 
-BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
-                             Error **errp)
-{
-    BlockDriverState *bs;
-    BlockDriverState *target_bs;
-    AioContext *aio_context;
-    BlockJob *job;
-
-    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
-    if (!bs) {
-        return NULL;
-    }
-
-    target_bs = bdrv_lookup_bs(backup->target, backup->target, errp);
-    if (!target_bs) {
-        return NULL;
-    }
-
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
-
-    job = do_backup_common(qapi_BlockdevBackup_base(backup),
-                           bs, target_bs, aio_context, txn, errp);
-
-    aio_context_release(aio_context);
-    return job;
-}
-
-void qmp_blockdev_backup(BlockdevBackup *arg, Error **errp)
+void qmp_blockdev_backup(BlockdevBackup *backup, Error **errp)
 {
-    BlockJob *job;
-    job = do_blockdev_backup(arg, NULL, errp);
-    if (job) {
-        job_start(&job->job);
-    }
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP,
+        .u.blockdev_backup.data = backup,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 /* Parameter check and block job starting for drive mirroring.
@@ -3881,6 +3894,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
     BlockDriverState *bs;
     BlockDriverState *source, *target_bs;
     AioContext *aio_context;
+    AioContext *old_context;
     BlockMirrorBackingMode backing_mode;
     Error *local_err = NULL;
     QDict *options = NULL;
@@ -3993,12 +4007,22 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
                    (arg->mode == NEW_IMAGE_MODE_EXISTING ||
                     !bdrv_has_zero_init(target_bs)));
 
+
+    /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
+    old_context = bdrv_get_aio_context(target_bs);
+    aio_context_release(aio_context);
+    aio_context_acquire(old_context);
+
     ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
     if (ret < 0) {
         bdrv_unref(target_bs);
-        goto out;
+        aio_context_release(old_context);
+        return;
     }
 
+    aio_context_release(old_context);
+    aio_context_acquire(aio_context);
+
     blockdev_mirror_common(arg->has_job_id ? arg->job_id : NULL, bs, target_bs,
                            arg->has_replaces, arg->replaces, arg->sync,
                            backing_mode, zero_target,
@@ -4040,6 +4064,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     AioContext *aio_context;
+    AioContext *old_context;
     BlockMirrorBackingMode backing_mode = MIRROR_LEAVE_BACKING_CHAIN;
     Error *local_err = NULL;
     bool zero_target;
@@ -4057,10 +4082,16 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
 
     zero_target = (sync == MIRROR_SYNC_MODE_FULL);
 
+    /* Honor bdrv_try_set_aio_context() context acquisition requirements. */
+    old_context = bdrv_get_aio_context(target_bs);
     aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
+    aio_context_acquire(old_context);
 
     ret = bdrv_try_set_aio_context(target_bs, aio_context, errp);
+
+    aio_context_release(old_context);
+    aio_context_acquire(aio_context);
+
     if (ret < 0) {
         goto out;
     }
diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index be35bde..0990681 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -530,6 +530,7 @@ class TestQuorum(iotests.QMPTestCase):
     children = []
     backing = []
 
+    @iotests.skip_if_unsupported(['quorum'])
     def setUp(self):
         opts = ['driver=quorum', 'vote-threshold=2']
 
@@ -560,9 +561,6 @@ class TestQuorum(iotests.QMPTestCase):
             os.remove(img)
 
     def test_stream_quorum(self):
-        if not iotests.supports_quorum():
-            return
-
         self.assertNotEqual(qemu_io('-f', iotests.imgfmt, '-rU', '-c', 'map', self.children[0]),
                             qemu_io('-f', iotests.imgfmt, '-rU', '-c', 'map', self.backing[0]),
                             'image file map matches backing file before streaming')
diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040
index 762ad1e..74f62c3 100755
--- a/tests/qemu-iotests/040
+++ b/tests/qemu-iotests/040
@@ -106,6 +106,7 @@ class TestSingleDrive(ImageCommitTestCase):
         self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
         self.assertEqual(-1, qemu_io('-f', 'raw', '-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
 
+    @iotests.skip_if_unsupported(['throttle'])
     def test_commit_with_filter_and_quit(self):
         result = self.vm.qmp('object-add', qom_type='throttle-group', id='tg')
         self.assert_qmp(result, 'return', {})
@@ -125,6 +126,7 @@ class TestSingleDrive(ImageCommitTestCase):
         self.has_quit = True
 
     # Same as above, but this time we add the filter after starting the job
+    @iotests.skip_if_unsupported(['throttle'])
     def test_commit_plus_filter_and_quit(self):
         result = self.vm.qmp('object-add', qom_type='throttle-group', id='tg')
         self.assert_qmp(result, 'return', {})
diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index d7be30b..c07437f 100755
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -871,6 +871,7 @@ class TestRepairQuorum(iotests.QMPTestCase):
     image_len = 1 * 1024 * 1024 # MB
     IMAGES = [ quorum_img1, quorum_img2, quorum_img3 ]
 
+    @iotests.skip_if_unsupported(['quorum'])
     def setUp(self):
         self.vm = iotests.VM()
 
@@ -891,9 +892,8 @@ class TestRepairQuorum(iotests.QMPTestCase):
         #assemble the quorum block device from the individual files
         args = { "driver": "quorum", "node-name": "quorum0",
                  "vote-threshold": 2, "children": [ "img0", "img1", "img2" ] }
-        if iotests.supports_quorum():
-            result = self.vm.qmp("blockdev-add", **args)
-            self.assert_qmp(result, 'return', {})
+        result = self.vm.qmp("blockdev-add", **args)
+        self.assert_qmp(result, 'return', {})
 
 
     def tearDown(self):
@@ -906,9 +906,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
                 pass
 
     def test_complete(self):
-        if not iotests.supports_quorum():
-            return
-
         self.assert_no_active_block_jobs()
 
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
@@ -925,9 +922,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
                         'target image does not match source after mirroring')
 
     def test_cancel(self):
-        if not iotests.supports_quorum():
-            return
-
         self.assert_no_active_block_jobs()
 
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
@@ -942,9 +936,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
         self.vm.shutdown()
 
     def test_cancel_after_ready(self):
-        if not iotests.supports_quorum():
-            return
-
         self.assert_no_active_block_jobs()
 
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
@@ -961,9 +952,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
                         'target image does not match source after mirroring')
 
     def test_pause(self):
-        if not iotests.supports_quorum():
-            return
-
         self.assert_no_active_block_jobs()
 
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
@@ -989,9 +977,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
                         'target image does not match source after mirroring')
 
     def test_medium_not_found(self):
-        if not iotests.supports_quorum():
-            return
-
         if iotests.qemu_default_machine != 'pc':
             return
 
@@ -1003,9 +988,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_image_not_found(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
                              sync='full', node_name='repair0', replaces='img1',
                              mode='existing', target=quorum_repair_img,
@@ -1013,9 +995,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_device_not_found(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('drive-mirror', job_id='job0',
                              device='nonexistent', sync='full',
                              node_name='repair0',
@@ -1024,9 +1003,6 @@ class TestRepairQuorum(iotests.QMPTestCase):
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_wrong_sync_mode(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('drive-mirror', device='quorum0', job_id='job0',
                              node_name='repair0',
                              replaces='img1',
@@ -1034,27 +1010,18 @@ class TestRepairQuorum(iotests.QMPTestCase):
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_no_node_name(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
                              sync='full', replaces='img1',
                              target=quorum_repair_img, format=iotests.imgfmt)
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_nonexistent_replaces(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('drive-mirror', job_id='job0', device='quorum0',
                              sync='full', node_name='repair0', replaces='img77',
                              target=quorum_repair_img, format=iotests.imgfmt)
         self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_after_a_quorum_snapshot(self):
-        if not iotests.supports_quorum():
-            return
-
         result = self.vm.qmp('blockdev-snapshot-sync', node_name='img1',
                              snapshot_file=quorum_snapshot_file,
                              snapshot_node_name="snap1");
diff --git a/tests/qemu-iotests/141.out b/tests/qemu-iotests/141.out
index 3645675..263b680 100644
--- a/tests/qemu-iotests/141.out
+++ b/tests/qemu-iotests/141.out
@@ -13,6 +13,8 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/m.
 Formatting 'TEST_DIR/o.IMGFMT', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/t.IMGFMT backing_fmt=IMGFMT
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "job0"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "paused", "id": "job0"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "job0"}}
 {'execute': 'blockdev-del', 'arguments': {'node-name': 'drv0'}}
 {"error": {"class": "GenericError", "desc": "Node 'drv0' is busy: node is used as backing hd of 'NODE_NAME'"}}
 {'execute': 'block-job-cancel', 'arguments': {'device': 'job0'}}
diff --git a/tests/qemu-iotests/185.out b/tests/qemu-iotests/185.out
index 8379ac5..9a3b657 100644
--- a/tests/qemu-iotests/185.out
+++ b/tests/qemu-iotests/185.out
@@ -65,6 +65,8 @@ Formatting 'TEST_DIR/t.qcow2.copy', fmt=qcow2 size=67108864 cluster_size=65536 l
 Formatting 'TEST_DIR/t.qcow2.copy', fmt=qcow2 size=67108864 cluster_size=65536 lazy_refcounts=off refcount_bits=16
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "disk"}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "disk"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "paused", "id": "disk"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "disk"}}
 {"return": {}}
 { 'execute': 'quit' }
 {"return": {}}
diff --git a/tests/qemu-iotests/219 b/tests/qemu-iotests/219
index e0c5166..655f54d 100755
--- a/tests/qemu-iotests/219
+++ b/tests/qemu-iotests/219
@@ -63,7 +63,7 @@ def test_pause_resume(vm):
                 # logged immediately
                 iotests.log(vm.qmp('query-jobs'))
 
-def test_job_lifecycle(vm, job, job_args, has_ready=False):
+def test_job_lifecycle(vm, job, job_args, has_ready=False, is_mirror=False):
     global img_size
 
     iotests.log('')
@@ -135,6 +135,9 @@ def test_job_lifecycle(vm, job, job_args, has_ready=False):
     iotests.log('Waiting for PENDING state...')
     iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
     iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
+    if is_mirror:
+        iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
+        iotests.log(iotests.filter_qmp_event(vm.event_wait('JOB_STATUS_CHANGE')))
 
     if not job_args.get('auto-finalize', True):
         # PENDING state:
@@ -218,7 +221,7 @@ with iotests.FilePath('disk.img') as disk_path, \
 
     for auto_finalize in [True, False]:
         for auto_dismiss in [True, False]:
-            test_job_lifecycle(vm, 'drive-backup', job_args={
+            test_job_lifecycle(vm, 'drive-backup', is_mirror=True, job_args={
                 'device': 'drive0-node',
                 'target': copy_path,
                 'sync': 'full',
diff --git a/tests/qemu-iotests/219.out b/tests/qemu-iotests/219.out
index 8ebd3fe..0ea5d0b 100644
--- a/tests/qemu-iotests/219.out
+++ b/tests/qemu-iotests/219.out
@@ -135,6 +135,8 @@ Pause/resume in RUNNING
 {"return": {}}
 
 Waiting for PENDING state...
+{"data": {"id": "job0", "status": "paused"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"id": "job0", "status": "running"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "waiting"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "pending"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "concluded"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -186,6 +188,8 @@ Pause/resume in RUNNING
 {"return": {}}
 
 Waiting for PENDING state...
+{"data": {"id": "job0", "status": "paused"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"id": "job0", "status": "running"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "waiting"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "pending"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "concluded"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
@@ -245,6 +249,8 @@ Pause/resume in RUNNING
 {"return": {}}
 
 Waiting for PENDING state...
+{"data": {"id": "job0", "status": "paused"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"id": "job0", "status": "running"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "waiting"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "pending"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"return": [{"current-progress": 4194304, "id": "job0", "status": "pending", "total-progress": 4194304, "type": "backup"}]}
@@ -304,6 +310,8 @@ Pause/resume in RUNNING
 {"return": {}}
 
 Waiting for PENDING state...
+{"data": {"id": "job0", "status": "paused"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"id": "job0", "status": "running"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "waiting"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"data": {"id": "job0", "status": "pending"}, "event": "JOB_STATUS_CHANGE", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 {"return": [{"current-progress": 4194304, "id": "job0", "status": "pending", "total-progress": 4194304, "type": "backup"}]}
diff --git a/tests/qemu-iotests/234 b/tests/qemu-iotests/234
index 34c818c..59a7f94 100755
--- a/tests/qemu-iotests/234
+++ b/tests/qemu-iotests/234
@@ -69,9 +69,9 @@ with iotests.FilePath('img') as img_path, \
     iotests.log(vm_a.qmp('migrate', uri='exec:cat >%s' % (fifo_a)))
     with iotests.Timeout(3, 'Migration does not complete'):
         # Wait for the source first (which includes setup=setup)
-        vm_a.wait_migration()
+        vm_a.wait_migration('postmigrate')
         # Wait for the destination second (which does not)
-        vm_b.wait_migration()
+        vm_b.wait_migration('running')
 
     iotests.log(vm_a.qmp('query-migrate')['return']['status'])
     iotests.log(vm_b.qmp('query-migrate')['return']['status'])
@@ -98,9 +98,9 @@ with iotests.FilePath('img') as img_path, \
     iotests.log(vm_b.qmp('migrate', uri='exec:cat >%s' % (fifo_b)))
     with iotests.Timeout(3, 'Migration does not complete'):
         # Wait for the source first (which includes setup=setup)
-        vm_b.wait_migration()
+        vm_b.wait_migration('postmigrate')
         # Wait for the destination second (which does not)
-        vm_a.wait_migration()
+        vm_a.wait_migration('running')
 
     iotests.log(vm_a.qmp('query-migrate')['return']['status'])
     iotests.log(vm_b.qmp('query-migrate')['return']['status'])
diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245
index e66a23c..d12b253 100644
--- a/tests/qemu-iotests/245
+++ b/tests/qemu-iotests/245
@@ -478,6 +478,7 @@ class TestBlockdevReopen(iotests.QMPTestCase):
     # This test verifies that we can't change the children of a block
     # device during a reopen operation in a way that would create
     # cycles in the node graph
+    @iotests.skip_if_unsupported(['blkverify'])
     def test_graph_cycles(self):
         opts = []
 
@@ -534,6 +535,7 @@ class TestBlockdevReopen(iotests.QMPTestCase):
         self.assert_qmp(result, 'return', {})
 
     # Misc reopen tests with different block drivers
+    @iotests.skip_if_unsupported(['quorum', 'throttle'])
     def test_misc_drivers(self):
         ####################
         ###### quorum ######
diff --git a/tests/qemu-iotests/262 b/tests/qemu-iotests/262
index 0963daa..bbcb526 100755
--- a/tests/qemu-iotests/262
+++ b/tests/qemu-iotests/262
@@ -71,9 +71,9 @@ with iotests.FilePath('img') as img_path, \
     iotests.log(vm_a.qmp('migrate', uri='exec:cat >%s' % (fifo)))
     with iotests.Timeout(3, 'Migration does not complete'):
         # Wait for the source first (which includes setup=setup)
-        vm_a.wait_migration()
+        vm_a.wait_migration('postmigrate')
         # Wait for the destination second (which does not)
-        vm_b.wait_migration()
+        vm_b.wait_migration('running')
 
     iotests.log(vm_a.qmp('query-migrate')['return']['status'])
     iotests.log(vm_b.qmp('query-migrate')['return']['status'])
diff --git a/tests/qemu-iotests/280 b/tests/qemu-iotests/280
index 0b1fa8e..85e9114 100755
--- a/tests/qemu-iotests/280
+++ b/tests/qemu-iotests/280
@@ -45,7 +45,7 @@ with iotests.FilePath('base') as base_path , \
     vm.qmp_log('migrate', uri='exec:cat > /dev/null')
 
     with iotests.Timeout(3, 'Migration does not complete'):
-        vm.wait_migration()
+        vm.wait_migration('postmigrate')
 
     iotests.log('\nVM is now stopped:')
     iotests.log(vm.qmp('query-migrate')['return']['status'])
diff --git a/tests/qemu-iotests/281 b/tests/qemu-iotests/281
new file mode 100755
index 0000000..269d583
--- /dev/null
+++ b/tests/qemu-iotests/281
@@ -0,0 +1,247 @@
+#!/usr/bin/env python
+#
+# Test cases for blockdev + IOThread interactions
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import iotests
+from iotests import qemu_img
+
+image_len = 64 * 1024 * 1024
+
+# Test for RHBZ#1782175
+class TestDirtyBitmapIOThread(iotests.QMPTestCase):
+    drive0_img = os.path.join(iotests.test_dir, 'drive0.img')
+    images = { 'drive0': drive0_img }
+
+    def setUp(self):
+        for name in self.images:
+            qemu_img('create', '-f', iotests.imgfmt,
+                     self.images[name], str(image_len))
+
+        self.vm = iotests.VM()
+        self.vm.add_object('iothread,id=iothread0')
+
+        for name in self.images:
+            self.vm.add_blockdev('driver=file,filename=%s,node-name=file_%s'
+                                 % (self.images[name], name))
+            self.vm.add_blockdev('driver=qcow2,file=file_%s,node-name=%s'
+                                 % (name, name))
+
+        self.vm.launch()
+        self.vm.qmp('x-blockdev-set-iothread',
+                    node_name='drive0', iothread='iothread0',
+                    force=True)
+
+    def tearDown(self):
+        self.vm.shutdown()
+        for name in self.images:
+            os.remove(self.images[name])
+
+    def test_add_dirty_bitmap(self):
+        result = self.vm.qmp(
+            'block-dirty-bitmap-add',
+            node='drive0',
+            name='bitmap1',
+            persistent=True,
+        )
+
+        self.assert_qmp(result, 'return', {})
+
+
+# Test for RHBZ#1746217 & RHBZ#1773517
+class TestNBDMirrorIOThread(iotests.QMPTestCase):
+    nbd_sock = os.path.join(iotests.sock_dir, 'nbd.sock')
+    drive0_img = os.path.join(iotests.test_dir, 'drive0.img')
+    mirror_img = os.path.join(iotests.test_dir, 'mirror.img')
+    images = { 'drive0': drive0_img, 'mirror': mirror_img }
+
+    def setUp(self):
+        for name in self.images:
+            qemu_img('create', '-f', iotests.imgfmt,
+                     self.images[name], str(image_len))
+
+        self.vm_src = iotests.VM(path_suffix='src')
+        self.vm_src.add_object('iothread,id=iothread0')
+        self.vm_src.add_blockdev('driver=file,filename=%s,node-name=file0'
+                          % (self.drive0_img))
+        self.vm_src.add_blockdev('driver=qcow2,file=file0,node-name=drive0')
+        self.vm_src.launch()
+        self.vm_src.qmp('x-blockdev-set-iothread',
+                        node_name='drive0', iothread='iothread0',
+                        force=True)
+
+        self.vm_tgt = iotests.VM(path_suffix='tgt')
+        self.vm_tgt.add_object('iothread,id=iothread0')
+        self.vm_tgt.add_blockdev('driver=file,filename=%s,node-name=file0'
+                          % (self.mirror_img))
+        self.vm_tgt.add_blockdev('driver=qcow2,file=file0,node-name=drive0')
+        self.vm_tgt.launch()
+        self.vm_tgt.qmp('x-blockdev-set-iothread',
+                        node_name='drive0', iothread='iothread0',
+                        force=True)
+
+    def tearDown(self):
+        self.vm_src.shutdown()
+        self.vm_tgt.shutdown()
+        for name in self.images:
+            os.remove(self.images[name])
+
+    def test_nbd_mirror(self):
+        result = self.vm_tgt.qmp(
+            'nbd-server-start',
+            addr={
+                'type': 'unix',
+                'data': { 'path': self.nbd_sock }
+            }
+        )
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm_tgt.qmp(
+            'nbd-server-add',
+            device='drive0',
+            writable=True
+        )
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm_src.qmp(
+            'drive-mirror',
+            device='drive0',
+            target='nbd+unix:///drive0?socket=' + self.nbd_sock,
+            sync='full',
+            mode='existing',
+            speed=64*1024*1024,
+            job_id='j1'
+        )
+        self.assert_qmp(result, 'return', {})
+
+        self.vm_src.event_wait(name="BLOCK_JOB_READY")
+
+
+# Test for RHBZ#1779036
+class TestExternalSnapshotAbort(iotests.QMPTestCase):
+    drive0_img = os.path.join(iotests.test_dir, 'drive0.img')
+    snapshot_img = os.path.join(iotests.test_dir, 'snapshot.img')
+    images = { 'drive0': drive0_img, 'snapshot': snapshot_img }
+
+    def setUp(self):
+        for name in self.images:
+            qemu_img('create', '-f', iotests.imgfmt,
+                     self.images[name], str(image_len))
+
+        self.vm = iotests.VM()
+        self.vm.add_object('iothread,id=iothread0')
+        self.vm.add_blockdev('driver=file,filename=%s,node-name=file0'
+                          % (self.drive0_img))
+        self.vm.add_blockdev('driver=qcow2,file=file0,node-name=drive0')
+        self.vm.launch()
+        self.vm.qmp('x-blockdev-set-iothread',
+                    node_name='drive0', iothread='iothread0',
+                    force=True)
+
+    def tearDown(self):
+        self.vm.shutdown()
+        for name in self.images:
+            os.remove(self.images[name])
+
+    def test_external_snapshot_abort(self):
+        # Use a two actions transaction with a bogus values on the second
+        # one to trigger an abort of the transaction.
+        result = self.vm.qmp('transaction', actions=[
+            {
+                'type': 'blockdev-snapshot-sync',
+                'data': { 'node-name': 'drive0',
+                          'snapshot-file': self.snapshot_img,
+                          'snapshot-node-name': 'snap1',
+                          'mode': 'absolute-paths',
+                          'format': 'qcow2' }
+            },
+            {
+                'type': 'blockdev-snapshot-sync',
+                'data': { 'node-name': 'drive0',
+                          'snapshot-file': '/fakesnapshot',
+                          'snapshot-node-name': 'snap2',
+                          'mode': 'absolute-paths',
+                          'format': 'qcow2' }
+            },
+        ])
+
+        # Crashes on failure, we expect this error.
+        self.assert_qmp(result, 'error/class', 'GenericError')
+
+
+# Test for RHBZ#1782111
+class TestBlockdevBackupAbort(iotests.QMPTestCase):
+    drive0_img = os.path.join(iotests.test_dir, 'drive0.img')
+    drive1_img = os.path.join(iotests.test_dir, 'drive1.img')
+    snap0_img = os.path.join(iotests.test_dir, 'snap0.img')
+    snap1_img = os.path.join(iotests.test_dir, 'snap1.img')
+    images = { 'drive0': drive0_img,
+               'drive1': drive1_img,
+               'snap0': snap0_img,
+               'snap1': snap1_img }
+
+    def setUp(self):
+        for name in self.images:
+            qemu_img('create', '-f', iotests.imgfmt,
+                     self.images[name], str(image_len))
+
+        self.vm = iotests.VM()
+        self.vm.add_object('iothread,id=iothread0')
+        self.vm.add_device('virtio-scsi,iothread=iothread0')
+
+        for name in self.images:
+            self.vm.add_blockdev('driver=file,filename=%s,node-name=file_%s'
+                                 % (self.images[name], name))
+            self.vm.add_blockdev('driver=qcow2,file=file_%s,node-name=%s'
+                                 % (name, name))
+
+        self.vm.add_device('scsi-hd,drive=drive0')
+        self.vm.add_device('scsi-hd,drive=drive1')
+        self.vm.launch()
+
+    def tearDown(self):
+        self.vm.shutdown()
+        for name in self.images:
+            os.remove(self.images[name])
+
+    def test_blockdev_backup_abort(self):
+        # Use a two actions transaction with a bogus values on the second
+        # one to trigger an abort of the transaction.
+        result = self.vm.qmp('transaction', actions=[
+            {
+                'type': 'blockdev-backup',
+                'data': { 'device': 'drive0',
+                          'target': 'snap0',
+                          'sync': 'full',
+                          'job-id': 'j1' }
+            },
+            {
+                'type': 'blockdev-backup',
+                'data': { 'device': 'drive1',
+                          'target': 'snap1',
+                          'sync': 'full' }
+            },
+        ])
+
+        # Hangs on failure, we expect this error.
+        self.assert_qmp(result, 'error/class', 'GenericError')
+
+if __name__ == '__main__':
+    iotests.main(supported_fmts=['qcow2'],
+                 supported_protocols=['file'])
diff --git a/tests/qemu-iotests/281.out b/tests/qemu-iotests/281.out
new file mode 100644
index 0000000..89968f3
--- /dev/null
+++ b/tests/qemu-iotests/281.out
@@ -0,0 +1,5 @@
+....
+----------------------------------------------------------------------
+Ran 4 tests
+
+OK
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index cb2b789..e041cc1 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -288,3 +288,4 @@
 277 rw quick
 279 rw backing quick
 280 rw migration quick
+281 rw quick
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 13fd8b5..0b62c42 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -668,12 +668,16 @@ class VM(qtest.QEMUQtestMachine):
             }
         ]))
 
-    def wait_migration(self):
+    def wait_migration(self, expect_runstate):
         while True:
             event = self.event_wait('MIGRATION')
             log(event, filters=[filter_qmp_event])
             if event['data']['status'] == 'completed':
                 break
+        # The event may occur in finish-migrate, so wait for the expected
+        # post-migration runstate
+        while self.qmp('query-status')['return']['status'] != expect_runstate:
+            pass
 
     def node_info(self, node_name):
         nodes = self.qmp('query-named-block-nodes')