]> git.proxmox.com Git - mirror_qemu.git/blobdiff - blockdev.c
block: minimal bounce buffer alignment
[mirror_qemu.git] / blockdev.c
index 57910b82c7adc3ce59173afeeebcd37ff2a3dfd0..5eaf77e5995689d0b18bbf597c849ac38f8eefdb 100644 (file)
@@ -180,21 +180,19 @@ QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
                     const char *optstr)
 {
     QemuOpts *opts;
-    char buf[32];
 
     opts = drive_def(optstr);
     if (!opts) {
         return NULL;
     }
     if (type != IF_DEFAULT) {
-        qemu_opt_set(opts, "if", if_name[type]);
+        qemu_opt_set(opts, "if", if_name[type], &error_abort);
     }
     if (index >= 0) {
-        snprintf(buf, sizeof(buf), "%d", index);
-        qemu_opt_set(opts, "index", buf);
+        qemu_opt_set_number(opts, "index", index, &error_abort);
     }
     if (file)
-        qemu_opt_set(opts, "file", file);
+        qemu_opt_set(opts, "file", file, &error_abort);
     return opts;
 }
 
@@ -354,13 +352,11 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     ThrottleConfig cfg;
     int snapshot = 0;
     bool copy_on_read;
-    int ret;
     Error *error = NULL;
     QemuOpts *opts;
     const char *id;
     bool has_driver_specific_opts;
     BlockdevDetectZeroesOptions detect_zeroes;
-    BlockDriver *drv = NULL;
 
     /* Check common options by copying from bs_opts to opts, all other options
      * stay in bs_opts for processing by bdrv_open(). */
@@ -426,11 +422,11 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
             goto early_err;
         }
 
-        drv = bdrv_find_format(buf);
-        if (!drv) {
-            error_setg(errp, "'%s' invalid format", buf);
+        if (qdict_haskey(bs_opts, "driver")) {
+            error_setg(errp, "Cannot specify both 'driver' and 'format'");
             goto early_err;
         }
+        qdict_put(bs_opts, "driver", qstring_from_str(buf));
     }
 
     /* disk I/O throttling */
@@ -505,70 +501,64 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     }
 
     /* init */
-    blk = blk_new_with_bs(qemu_opts_id(opts), errp);
-    if (!blk) {
-        goto early_err;
-    }
-    bs = blk_bs(blk);
-    bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0;
-    bs->read_only = ro;
-    bs->detect_zeroes = detect_zeroes;
-
-    bdrv_set_on_error(bs, on_read_error, on_write_error);
+    if ((!file || !*file) && !has_driver_specific_opts) {
+        blk = blk_new_with_bs(qemu_opts_id(opts), errp);
+        if (!blk) {
+            goto early_err;
+        }
 
-    /* disk I/O throttling */
-    if (throttle_enabled(&cfg)) {
-        bdrv_io_limits_enable(bs);
-        bdrv_set_io_limits(bs, &cfg);
-    }
+        bs = blk_bs(blk);
+        bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0;
+        bs->read_only = ro;
 
-    if (!file || !*file) {
-        if (has_driver_specific_opts) {
+        QDECREF(bs_opts);
+    } else {
+        if (file && !*file) {
             file = NULL;
-        } else {
-            QDECREF(bs_opts);
-            qemu_opts_del(opts);
-            return blk;
         }
-    }
-    if (snapshot) {
-        /* always use cache=unsafe with snapshot */
-        bdrv_flags &= ~BDRV_O_CACHE_MASK;
-        bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
-    }
 
-    if (copy_on_read) {
-        bdrv_flags |= BDRV_O_COPY_ON_READ;
-    }
+        if (snapshot) {
+            /* always use cache=unsafe with snapshot */
+            bdrv_flags &= ~BDRV_O_CACHE_MASK;
+            bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
+        }
 
-    if (runstate_check(RUN_STATE_INMIGRATE)) {
-        bdrv_flags |= BDRV_O_INCOMING;
+        if (copy_on_read) {
+            bdrv_flags |= BDRV_O_COPY_ON_READ;
+        }
+
+        if (runstate_check(RUN_STATE_INMIGRATE)) {
+            bdrv_flags |= BDRV_O_INCOMING;
+        }
+
+        bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
+
+        blk = blk_new_open(qemu_opts_id(opts), file, NULL, bs_opts, bdrv_flags,
+                           errp);
+        if (!blk) {
+            goto err_no_bs_opts;
+        }
+        bs = blk_bs(blk);
     }
 
-    bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
+    bs->detect_zeroes = detect_zeroes;
 
-    QINCREF(bs_opts);
-    ret = bdrv_open(&bs, file, NULL, bs_opts, bdrv_flags, drv, &error);
-    assert(bs == blk_bs(blk));
+    bdrv_set_on_error(bs, on_read_error, on_write_error);
 
-    if (ret < 0) {
-        error_setg(errp, "could not open disk image %s: %s",
-                   file ?: blk_name(blk), error_get_pretty(error));
-        error_free(error);
-        goto err;
+    /* disk I/O throttling */
+    if (throttle_enabled(&cfg)) {
+        bdrv_io_limits_enable(bs);
+        bdrv_set_io_limits(bs, &cfg);
     }
 
     if (bdrv_key_required(bs)) {
         autostart = 0;
     }
 
-    QDECREF(bs_opts);
+err_no_bs_opts:
     qemu_opts_del(opts);
-
     return blk;
 
-err:
-    blk_unref(blk);
 early_err:
     qemu_opts_del(opts);
 err_no_opts:
@@ -592,7 +582,7 @@ static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to,
 
     /* rename all items in opts */
     while ((value = qemu_opt_get(opts, from))) {
-        qemu_opt_set(opts, to, value);
+        qemu_opt_set(opts, to, value, &error_abort);
         qemu_opt_unset(opts, from);
     }
 }
@@ -728,8 +718,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
         qemu_opt_rename(all_opts, opt_renames[i].from, opt_renames[i].to,
                         &local_err);
         if (local_err) {
-            error_report("%s", error_get_pretty(local_err));
-            error_free(local_err);
+            error_report_err(local_err);
             return NULL;
         }
     }
@@ -746,15 +735,15 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
         /* Specific options take precedence */
         if (!qemu_opt_get(all_opts, "cache.writeback")) {
             qemu_opt_set_bool(all_opts, "cache.writeback",
-                              !!(flags & BDRV_O_CACHE_WB));
+                              !!(flags & BDRV_O_CACHE_WB), &error_abort);
         }
         if (!qemu_opt_get(all_opts, "cache.direct")) {
             qemu_opt_set_bool(all_opts, "cache.direct",
-                              !!(flags & BDRV_O_NOCACHE));
+                              !!(flags & BDRV_O_NOCACHE), &error_abort);
         }
         if (!qemu_opt_get(all_opts, "cache.no-flush")) {
             qemu_opt_set_bool(all_opts, "cache.no-flush",
-                              !!(flags & BDRV_O_NO_FLUSH));
+                              !!(flags & BDRV_O_NO_FLUSH), &error_abort);
         }
         qemu_opt_unset(all_opts, "cache");
     }
@@ -767,8 +756,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
                                    &error_abort);
     qemu_opts_absorb_qdict(legacy_opts, bs_opts, &local_err);
     if (local_err) {
-        error_report("%s", error_get_pretty(local_err));
-        error_free(local_err);
+        error_report_err(local_err);
         goto fail;
     }
 
@@ -945,13 +933,14 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
         devopts = qemu_opts_create(qemu_find_opts("device"), NULL, 0,
                                    &error_abort);
         if (arch_type == QEMU_ARCH_S390X) {
-            qemu_opt_set(devopts, "driver", "virtio-blk-s390");
+            qemu_opt_set(devopts, "driver", "virtio-blk-s390", &error_abort);
         } else {
-            qemu_opt_set(devopts, "driver", "virtio-blk-pci");
+            qemu_opt_set(devopts, "driver", "virtio-blk-pci", &error_abort);
         }
-        qemu_opt_set(devopts, "drive", qdict_get_str(bs_opts, "id"));
+        qemu_opt_set(devopts, "drive", qdict_get_str(bs_opts, "id"),
+                     &error_abort);
         if (devaddr) {
-            qemu_opt_set(devopts, "addr", devaddr);
+            qemu_opt_set(devopts, "addr", devaddr, &error_abort);
         }
     }
 
@@ -983,8 +972,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     bs_opts = NULL;
     if (!blk) {
         if (local_err) {
-            error_report("%s", error_get_pretty(local_err));
-            error_free(local_err);
+            error_report_err(local_err);
         }
         goto fail;
     } else {
@@ -1025,21 +1013,21 @@ fail:
     return dinfo;
 }
 
-void do_commit(Monitor *mon, const QDict *qdict)
+void hmp_commit(Monitor *mon, const QDict *qdict)
 {
     const char *device = qdict_get_str(qdict, "device");
-    BlockDriverState *bs;
+    BlockBackend *blk;
     int ret;
 
     if (!strcmp(device, "all")) {
         ret = bdrv_commit_all();
     } else {
-        bs = bdrv_find(device);
-        if (!bs) {
+        blk = blk_by_name(device);
+        if (!blk) {
             monitor_printf(mon, "Device '%s' not found\n", device);
             return;
         }
-        ret = bdrv_commit(bs);
+        ret = bdrv_commit(blk_bs(blk));
     }
     if (ret < 0) {
         monitor_printf(mon, "'commit' error for '%s': %s\n", device,
@@ -1104,16 +1092,20 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
                                                          const char *name,
                                                          Error **errp)
 {
-    BlockDriverState *bs = bdrv_find(device);
+    BlockDriverState *bs;
+    BlockBackend *blk;
+    AioContext *aio_context;
     QEMUSnapshotInfo sn;
     Error *local_err = NULL;
     SnapshotInfo *info = NULL;
     int ret;
 
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return NULL;
     }
+    bs = blk_bs(blk);
 
     if (!has_id) {
         id = NULL;
@@ -1128,25 +1120,34 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
         return NULL;
     }
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE, errp)) {
+        goto out_aio_context;
+    }
+
     ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return NULL;
+        goto out_aio_context;
     }
     if (!ret) {
         error_setg(errp,
                    "Snapshot with id '%s' and name '%s' does not exist on "
                    "device '%s'",
                    STR_OR_NULL(id), STR_OR_NULL(name), device);
-        return NULL;
+        goto out_aio_context;
     }
 
     bdrv_snapshot_delete(bs, id, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return NULL;
+        goto out_aio_context;
     }
 
+    aio_context_release(aio_context);
+
     info = g_new0(SnapshotInfo, 1);
     info->id = g_strdup(sn.id_str);
     info->name = g_strdup(sn.name);
@@ -1157,9 +1158,75 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
     info->vm_clock_sec = sn.vm_clock_nsec / 1000000000;
 
     return info;
+
+out_aio_context:
+    aio_context_release(aio_context);
+    return NULL;
 }
 
-/* New and old BlockDriverState structs for group snapshots */
+/**
+ * block_dirty_bitmap_lookup:
+ * Return a dirty bitmap (if present), after validating
+ * the node reference and bitmap names.
+ *
+ * @node: The name of the BDS node to search for bitmaps
+ * @name: The name of the bitmap to search for
+ * @pbs: Output pointer for BDS lookup, if desired. Can be NULL.
+ * @paio: Output pointer for aio_context acquisition, if desired. Can be NULL.
+ * @errp: Output pointer for error information. Can be NULL.
+ *
+ * @return: A bitmap object on success, or NULL on failure.
+ */
+static BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node,
+                                                  const char *name,
+                                                  BlockDriverState **pbs,
+                                                  AioContext **paio,
+                                                  Error **errp)
+{
+    BlockDriverState *bs;
+    BdrvDirtyBitmap *bitmap;
+    AioContext *aio_context;
+
+    if (!node) {
+        error_setg(errp, "Node cannot be NULL");
+        return NULL;
+    }
+    if (!name) {
+        error_setg(errp, "Bitmap name cannot be NULL");
+        return NULL;
+    }
+    bs = bdrv_lookup_bs(node, node, NULL);
+    if (!bs) {
+        error_setg(errp, "Node '%s' not found", node);
+        return NULL;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bitmap = bdrv_find_dirty_bitmap(bs, name);
+    if (!bitmap) {
+        error_setg(errp, "Dirty bitmap '%s' not found", name);
+        goto fail;
+    }
+
+    if (pbs) {
+        *pbs = bs;
+    }
+    if (paio) {
+        *paio = aio_context;
+    } else {
+        aio_context_release(aio_context);
+    }
+
+    return bitmap;
+
+ fail:
+    aio_context_release(aio_context);
+    return NULL;
+}
+
+/* New and old BlockDriverState structs for atomic group operations */
 
 typedef struct BlkTransactionState BlkTransactionState;
 
@@ -1193,6 +1260,7 @@ struct BlkTransactionState {
 typedef struct InternalSnapshotState {
     BlkTransactionState common;
     BlockDriverState *bs;
+    AioContext *aio_context;
     QEMUSnapshotInfo sn;
 } InternalSnapshotState;
 
@@ -1202,6 +1270,7 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     Error *local_err = NULL;
     const char *device;
     const char *name;
+    BlockBackend *blk;
     BlockDriverState *bs;
     QEMUSnapshotInfo old_sn, *sn;
     bool ret;
@@ -1220,25 +1289,35 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     name = internal->name;
 
     /* 2. check for validation */
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
+
+    /* AioContext is released in .clean() */
+    state->aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(state->aio_context);
 
     if (!bdrv_is_inserted(bs)) {
         error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         return;
     }
 
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)) {
+        return;
+    }
+
     if (bdrv_is_read_only(bs)) {
-        error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
+        error_setg(errp, "Device '%s' is read only", device);
         return;
     }
 
     if (!bdrv_can_snapshot(bs)) {
-        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
-                  bs->drv->format_name, device, "internal snapshot");
+        error_setg(errp, "Block format '%s' used by device '%s' "
+                   "does not support internal snapshots",
+                   bs->drv->format_name, device);
         return;
     }
 
@@ -1303,11 +1382,22 @@ static void internal_snapshot_abort(BlkTransactionState *common)
     }
 }
 
+static void internal_snapshot_clean(BlkTransactionState *common)
+{
+    InternalSnapshotState *state = DO_UPCAST(InternalSnapshotState,
+                                             common, common);
+
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
+}
+
 /* external snapshot private data */
 typedef struct ExternalSnapshotState {
     BlkTransactionState common;
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
+    AioContext *aio_context;
 } ExternalSnapshotState;
 
 static void external_snapshot_prepare(BlkTransactionState *common,
@@ -1374,6 +1464,10 @@ static void external_snapshot_prepare(BlkTransactionState *common,
         return;
     }
 
+    /* Acquire AioContext now so any threads operating on old_bs stop */
+    state->aio_context = bdrv_get_aio_context(state->old_bs);
+    aio_context_acquire(state->aio_context);
+
     if (!bdrv_is_inserted(state->old_bs)) {
         error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         return;
@@ -1432,6 +1526,8 @@ static void external_snapshot_commit(BlkTransactionState *common)
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
 
+    bdrv_set_aio_context(state->new_bs, state->aio_context);
+
     /* This removes our old bs and adds the new bs */
     bdrv_append(state->new_bs, state->old_bs);
     /* We don't need (or want) to use the transactional
@@ -1439,6 +1535,8 @@ static void external_snapshot_commit(BlkTransactionState *common)
      * don't want to abort all of them if one of them fails the reopen */
     bdrv_reopen(state->new_bs, state->new_bs->open_flags & ~BDRV_O_RDWR,
                 NULL);
+
+    aio_context_release(state->aio_context);
 }
 
 static void external_snapshot_abort(BlkTransactionState *common)
@@ -1448,39 +1546,55 @@ static void external_snapshot_abort(BlkTransactionState *common)
     if (state->new_bs) {
         bdrv_unref(state->new_bs);
     }
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
 }
 
 typedef struct DriveBackupState {
     BlkTransactionState common;
     BlockDriverState *bs;
+    AioContext *aio_context;
     BlockJob *job;
 } DriveBackupState;
 
 static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+    BlockDriverState *bs;
+    BlockBackend *blk;
     DriveBackup *backup;
     Error *local_err = NULL;
 
     assert(common->action->kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
     backup = common->action->drive_backup;
 
+    blk = blk_by_name(backup->device);
+    if (!blk) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, backup->device);
+        return;
+    }
+    bs = blk_bs(blk);
+
+    /* AioContext is released in .clean() */
+    state->aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(state->aio_context);
+
     qmp_drive_backup(backup->device, backup->target,
                      backup->has_format, backup->format,
                      backup->sync,
                      backup->has_mode, backup->mode,
                      backup->has_speed, backup->speed,
+                     backup->has_bitmap, backup->bitmap,
                      backup->has_on_source_error, backup->on_source_error,
                      backup->has_on_target_error, backup->on_target_error,
                      &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        state->bs = NULL;
-        state->job = NULL;
         return;
     }
 
-    state->bs = bdrv_find(backup->device);
+    state->bs = bs;
     state->job = state->bs->job;
 }
 
@@ -1495,6 +1609,91 @@ static void drive_backup_abort(BlkTransactionState *common)
     }
 }
 
+static void drive_backup_clean(BlkTransactionState *common)
+{
+    DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
+}
+
+typedef struct BlockdevBackupState {
+    BlkTransactionState common;
+    BlockDriverState *bs;
+    BlockJob *job;
+    AioContext *aio_context;
+} BlockdevBackupState;
+
+static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
+    BlockdevBackup *backup;
+    BlockDriverState *bs, *target;
+    BlockBackend *blk;
+    Error *local_err = NULL;
+
+    assert(common->action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
+    backup = common->action->blockdev_backup;
+
+    blk = blk_by_name(backup->device);
+    if (!blk) {
+        error_setg(errp, "Device '%s' not found", backup->device);
+        return;
+    }
+    bs = blk_bs(blk);
+
+    blk = blk_by_name(backup->target);
+    if (!blk) {
+        error_setg(errp, "Device '%s' not found", backup->target);
+        return;
+    }
+    target = blk_bs(blk);
+
+    /* AioContext is released in .clean() */
+    state->aio_context = bdrv_get_aio_context(bs);
+    if (state->aio_context != bdrv_get_aio_context(target)) {
+        state->aio_context = NULL;
+        error_setg(errp, "Backup between two IO threads is not implemented");
+        return;
+    }
+    aio_context_acquire(state->aio_context);
+
+    qmp_blockdev_backup(backup->device, backup->target,
+                        backup->sync,
+                        backup->has_speed, backup->speed,
+                        backup->has_on_source_error, backup->on_source_error,
+                        backup->has_on_target_error, backup->on_target_error,
+                        &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    state->bs = bs;
+    state->job = state->bs->job;
+}
+
+static void blockdev_backup_abort(BlkTransactionState *common)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
+    BlockDriverState *bs = state->bs;
+
+    /* Only cancel if it's the job we started */
+    if (bs && bs->job && bs->job == state->job) {
+        block_job_cancel_sync(bs->job);
+    }
+}
+
+static void blockdev_backup_clean(BlkTransactionState *common)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
+
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
+}
+
 static void abort_prepare(BlkTransactionState *common, Error **errp)
 {
     error_setg(errp, "Transaction aborted using Abort action");
@@ -1516,6 +1715,13 @@ static const BdrvActionOps actions[] = {
         .instance_size = sizeof(DriveBackupState),
         .prepare = drive_backup_prepare,
         .abort = drive_backup_abort,
+        .clean = drive_backup_clean,
+    },
+    [TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP] = {
+        .instance_size = sizeof(BlockdevBackupState),
+        .prepare = blockdev_backup_prepare,
+        .abort = blockdev_backup_abort,
+        .clean = blockdev_backup_clean,
     },
     [TRANSACTION_ACTION_KIND_ABORT] = {
         .instance_size = sizeof(BlkTransactionState),
@@ -1526,13 +1732,13 @@ static const BdrvActionOps actions[] = {
         .instance_size = sizeof(InternalSnapshotState),
         .prepare  = internal_snapshot_prepare,
         .abort = internal_snapshot_abort,
+        .clean = internal_snapshot_clean,
     },
 };
 
 /*
- * 'Atomic' group snapshots.  The snapshots are taken as a set, and if any fail
- *  then we do not pivot any of the devices in the group, and abandon the
- *  snapshots
+ * 'Atomic' group operations.  The operations are performed as a set, and if
+ * any fail then we roll back all operations in the group.
  */
 void qmp_transaction(TransactionActionList *dev_list, Error **errp)
 {
@@ -1543,10 +1749,10 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
     QSIMPLEQ_HEAD(snap_bdrv_states, BlkTransactionState) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
 
-    /* drain all i/o before any snapshots */
+    /* drain all i/o before any operations */
     bdrv_drain_all();
 
-    /* We don't do anything in this loop that commits us to the snapshot */
+    /* We don't do anything in this loop that commits us to the operations */
     while (NULL != dev_entry) {
         TransactionAction *dev_info = NULL;
         const BdrvActionOps *ops;
@@ -1581,10 +1787,7 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
     goto exit;
 
 delete_and_fail:
-    /*
-    * failure, and it is all-or-none; abandon each new bs, and keep using
-    * the original bs for all images
-    */
+    /* failure, and it is all-or-none; roll back all operations */
     QSIMPLEQ_FOREACH(state, &snap_bdrv_states, entry) {
         if (state->ops->abort) {
             state->ops->abort(state);
@@ -1603,14 +1806,18 @@ exit:
 static void eject_device(BlockBackend *blk, int force, Error **errp)
 {
     BlockDriverState *bs = blk_bs(blk);
+    AioContext *aio_context;
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
 
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {
-        return;
+        goto out;
     }
     if (!blk_dev_has_removable_media(blk)) {
         error_setg(errp, "Device '%s' is not removable",
                    bdrv_get_device_name(bs));
-        return;
+        goto out;
     }
 
     if (blk_dev_is_medium_locked(blk) && !blk_dev_is_tray_open(blk)) {
@@ -1618,11 +1825,14 @@ static void eject_device(BlockBackend *blk, int force, Error **errp)
         if (!force) {
             error_setg(errp, "Device '%s' is locked",
                        bdrv_get_device_name(bs));
-            return;
+            goto out;
         }
     }
 
     bdrv_close(bs);
+
+out:
+    aio_context_release(aio_context);
 }
 
 void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
@@ -1644,7 +1854,7 @@ void qmp_block_passwd(bool has_device, const char *device,
 {
     Error *local_err = NULL;
     BlockDriverState *bs;
-    int err;
+    AioContext *aio_context;
 
     bs = bdrv_lookup_bs(has_device ? device : NULL,
                         has_node_name ? node_name : NULL,
@@ -1654,16 +1864,15 @@ void qmp_block_passwd(bool has_device, const char *device,
         return;
     }
 
-    err = bdrv_set_key(bs, password);
-    if (err == -EINVAL) {
-        error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
-        return;
-    } else if (err < 0) {
-        error_set(errp, QERR_INVALID_PASSWORD);
-        return;
-    }
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_add_key(bs, password, errp);
+
+    aio_context_release(aio_context);
 }
 
+/* Assumes AioContext is held */
 static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
                                     int bdrv_flags, BlockDriver *drv,
                                     const char *password, Error **errp)
@@ -1677,18 +1886,7 @@ static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
         return;
     }
 
-    if (bdrv_key_required(bs)) {
-        if (password) {
-            if (bdrv_set_key(bs, password) < 0) {
-                error_set(errp, QERR_INVALID_PASSWORD);
-            }
-        } else {
-            error_set(errp, QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
-                      bdrv_get_encrypted_filename(bs));
-        }
-    } else if (password) {
-        error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
-    }
+    bdrv_add_key(bs, password, errp);
 }
 
 void qmp_change_blockdev(const char *device, const char *filename,
@@ -1696,6 +1894,7 @@ void qmp_change_blockdev(const char *device, const char *filename,
 {
     BlockBackend *blk;
     BlockDriverState *bs;
+    AioContext *aio_context;
     BlockDriver *drv = NULL;
     int bdrv_flags;
     Error *err = NULL;
@@ -1707,24 +1906,30 @@ void qmp_change_blockdev(const char *device, const char *filename,
     }
     bs = blk_bs(blk);
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
     if (format) {
         drv = bdrv_find_whitelisted_format(format, bs->read_only);
         if (!drv) {
             error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            return;
+            goto out;
         }
     }
 
     eject_device(blk, 0, &err);
     if (err) {
         error_propagate(errp, err);
-        return;
+        goto out;
     }
 
     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 
     qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, NULL, errp);
+
+out:
+    aio_context_release(aio_context);
 }
 
 /* throttling disk I/O limits */
@@ -1750,13 +1955,15 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
 {
     ThrottleConfig cfg;
     BlockDriverState *bs;
+    BlockBackend *blk;
     AioContext *aio_context;
 
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
 
     memset(&cfg, 0, sizeof(cfg));
     cfg.buckets[THROTTLE_BPS_TOTAL].avg = bps;
@@ -1810,7 +2017,103 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
     aio_context_release(aio_context);
 }
 
-int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
+void qmp_block_dirty_bitmap_add(const char *node, const char *name,
+                                bool has_granularity, uint32_t granularity,
+                                Error **errp)
+{
+    AioContext *aio_context;
+    BlockDriverState *bs;
+
+    if (!name || name[0] == '\0') {
+        error_setg(errp, "Bitmap name cannot be empty");
+        return;
+    }
+
+    bs = bdrv_lookup_bs(node, node, errp);
+    if (!bs) {
+        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");
+            goto out;
+        }
+    } else {
+        /* Default to cluster size, if available: */
+        granularity = bdrv_get_default_bitmap_granularity(bs);
+    }
+
+    bdrv_create_dirty_bitmap(bs, granularity, name, errp);
+
+ out:
+    aio_context_release(aio_context);
+}
+
+void qmp_block_dirty_bitmap_remove(const char *node, const char *name,
+                                   Error **errp)
+{
+    AioContext *aio_context;
+    BlockDriverState *bs;
+    BdrvDirtyBitmap *bitmap;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, &aio_context, errp);
+    if (!bitmap || !bs) {
+        return;
+    }
+
+    if (bdrv_dirty_bitmap_frozen(bitmap)) {
+        error_setg(errp,
+                   "Bitmap '%s' is currently frozen and cannot be removed",
+                   name);
+        goto out;
+    }
+    bdrv_dirty_bitmap_make_anon(bitmap);
+    bdrv_release_dirty_bitmap(bs, bitmap);
+
+ out:
+    aio_context_release(aio_context);
+}
+
+/**
+ * Completely clear a bitmap, for the purposes of synchronizing a bitmap
+ * immediately after a full backup operation.
+ */
+void qmp_block_dirty_bitmap_clear(const char *node, const char *name,
+                                  Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, &aio_context, errp);
+    if (!bitmap || !bs) {
+        return;
+    }
+
+    if (bdrv_dirty_bitmap_frozen(bitmap)) {
+        error_setg(errp,
+                   "Bitmap '%s' is currently frozen and cannot be modified",
+                   name);
+        goto out;
+    } else if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+        error_setg(errp,
+                   "Bitmap '%s' is currently disabled and cannot be cleared",
+                   name);
+        goto out;
+    }
+
+    bdrv_clear_dirty_bitmap(bitmap);
+
+ out:
+    aio_context_release(aio_context);
+}
+
+int hmp_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
     BlockBackend *blk;
@@ -1835,8 +2138,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
     aio_context_acquire(aio_context);
 
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
-        error_report("%s", error_get_pretty(local_err));
-        error_free(local_err);
+        error_report_err(local_err);
         aio_context_release(aio_context);
         return -1;
     }
@@ -1852,7 +2154,7 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
      * then we can just get rid of the block driver state right here.
      */
     if (blk_get_attached_dev(blk)) {
-        blk_hide_on_behalf_of_do_drive_del(blk);
+        blk_hide_on_behalf_of_hmp_drive_del(blk);
         /* Further I/O must not pause the guest */
         bdrv_set_on_error(bs, BLOCKDEV_ON_ERROR_REPORT,
                           BLOCKDEV_ON_ERROR_REPORT);
@@ -1913,7 +2215,7 @@ void qmp_block_resize(bool has_device, const char *device,
         error_set(errp, QERR_UNSUPPORTED);
         break;
     case -EACCES:
-        error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
+        error_setg(errp, "Device '%s' is read only", device);
         break;
     case -EBUSY:
         error_set(errp, QERR_DEVICE_IN_USE, device);
@@ -1961,6 +2263,7 @@ void qmp_block_stream(const char *device,
                       bool has_on_error, BlockdevOnError on_error,
                       Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *base_bs = NULL;
     AioContext *aio_context;
@@ -1971,11 +2274,12 @@ void qmp_block_stream(const char *device,
         on_error = BLOCKDEV_ON_ERROR_REPORT;
     }
 
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
@@ -2025,6 +2329,7 @@ void qmp_block_commit(const char *device,
                       bool has_speed, int64_t speed,
                       Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *base_bs, *top_bs;
     AioContext *aio_context;
@@ -2043,11 +2348,12 @@ void qmp_block_commit(const char *device,
      *  live commit feature versions; for this to work, we must make sure to
      *  perform the device lookup before any generic errors that may occur in a
      *  scenario in which all optional arguments are omitted. */
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
@@ -2055,7 +2361,7 @@ void qmp_block_commit(const char *device,
     /* drain all i/o before commits */
     bdrv_drain_all();
 
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, errp)) {
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) {
         goto out;
     }
 
@@ -2088,6 +2394,10 @@ void qmp_block_commit(const char *device,
 
     assert(bdrv_get_aio_context(base_bs) == aio_context);
 
+    if (bdrv_op_is_blocked(base_bs, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {
+        goto out;
+    }
+
     /* Do not allow attempts to commit an image into itself */
     if (top_bs == base_bs) {
         error_setg(errp, "cannot commit an image into itself");
@@ -2120,13 +2430,16 @@ void qmp_drive_backup(const char *device, const char *target,
                       enum MirrorSyncMode sync,
                       bool has_mode, enum NewImageMode mode,
                       bool has_speed, int64_t speed,
+                      bool has_bitmap, const char *bitmap,
                       bool has_on_source_error, BlockdevOnError on_source_error,
                       bool has_on_target_error, BlockdevOnError on_target_error,
                       Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     BlockDriverState *source = NULL;
+    BdrvDirtyBitmap *bmap = NULL;
     AioContext *aio_context;
     BlockDriver *drv = NULL;
     Error *local_err = NULL;
@@ -2147,15 +2460,18 @@ void qmp_drive_backup(const char *device, const char *target,
         mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
     }
 
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
+    /* Although backup_run has this check too, we need to use bs->drv below, so
+     * do an early check redundantly. */
     if (!bdrv_is_inserted(bs)) {
         error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         goto out;
@@ -2172,6 +2488,7 @@ void qmp_drive_backup(const char *device, const char *target,
         }
     }
 
+    /* Early check to avoid creating target */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
         goto out;
     }
@@ -2222,7 +2539,16 @@ void qmp_drive_backup(const char *device, const char *target,
 
     bdrv_set_aio_context(target_bs, aio_context);
 
-    backup_start(bs, target_bs, speed, sync, on_source_error, on_target_error,
+    if (has_bitmap) {
+        bmap = bdrv_find_dirty_bitmap(bs, bitmap);
+        if (!bmap) {
+            error_setg(errp, "Bitmap '%s' could not be found", bitmap);
+            goto out;
+        }
+    }
+
+    backup_start(bs, target_bs, speed, sync, bmap,
+                 on_source_error, on_target_error,
                  block_job_cb, bs, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
@@ -2236,7 +2562,61 @@ out:
 
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 {
-    return bdrv_named_nodes_list();
+    return bdrv_named_nodes_list(errp);
+}
+
+void qmp_blockdev_backup(const char *device, const char *target,
+                         enum MirrorSyncMode sync,
+                         bool has_speed, int64_t speed,
+                         bool has_on_source_error,
+                         BlockdevOnError on_source_error,
+                         bool has_on_target_error,
+                         BlockdevOnError on_target_error,
+                         Error **errp)
+{
+    BlockBackend *blk;
+    BlockDriverState *bs;
+    BlockDriverState *target_bs;
+    Error *local_err = NULL;
+    AioContext *aio_context;
+
+    if (!has_speed) {
+        speed = 0;
+    }
+    if (!has_on_source_error) {
+        on_source_error = BLOCKDEV_ON_ERROR_REPORT;
+    }
+    if (!has_on_target_error) {
+        on_target_error = BLOCKDEV_ON_ERROR_REPORT;
+    }
+
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_setg(errp, "Device '%s' not found", device);
+        return;
+    }
+    bs = blk_bs(blk);
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    blk = blk_by_name(target);
+    if (!blk) {
+        error_setg(errp, "Device '%s' not found", target);
+        goto out;
+    }
+    target_bs = blk_bs(blk);
+
+    bdrv_ref(target_bs);
+    bdrv_set_aio_context(target_bs, aio_context);
+    backup_start(bs, target_bs, speed, sync, NULL, on_source_error,
+                 on_target_error, block_job_cb, bs, &local_err);
+    if (local_err != NULL) {
+        bdrv_unref(target_bs);
+        error_propagate(errp, local_err);
+    }
+out:
+    aio_context_release(aio_context);
 }
 
 #define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
@@ -2254,6 +2634,7 @@ void qmp_drive_mirror(const char *device, const char *target,
                       bool has_on_target_error, BlockdevOnError on_target_error,
                       Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *source, *target_bs;
     AioContext *aio_context;
@@ -2293,11 +2674,12 @@ void qmp_drive_mirror(const char *device, const char *target,
         return;
     }
 
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
@@ -2432,14 +2814,17 @@ out:
 }
 
 /* Get the block job for a given device name and acquire its AioContext */
-static BlockJob *find_block_job(const char *device, AioContext **aio_context)
+static BlockJob *find_block_job(const char *device, AioContext **aio_context,
+                                Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs;
 
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         goto notfound;
     }
+    bs = blk_bs(blk);
 
     *aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(*aio_context);
@@ -2452,6 +2837,8 @@ static BlockJob *find_block_job(const char *device, AioContext **aio_context)
     return bs->job;
 
 notfound:
+    error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
+              "No active block job on device '%s'", device);
     *aio_context = NULL;
     return NULL;
 }
@@ -2459,10 +2846,9 @@ notfound:
 void qmp_block_job_set_speed(const char *device, int64_t speed, Error **errp)
 {
     AioContext *aio_context;
-    BlockJob *job = find_block_job(device, &aio_context);
+    BlockJob *job = find_block_job(device, &aio_context, errp);
 
     if (!job) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
         return;
     }
 
@@ -2474,10 +2860,9 @@ void qmp_block_job_cancel(const char *device,
                           bool has_force, bool force, Error **errp)
 {
     AioContext *aio_context;
-    BlockJob *job = find_block_job(device, &aio_context);
+    BlockJob *job = find_block_job(device, &aio_context, errp);
 
     if (!job) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
         return;
     }
 
@@ -2485,7 +2870,7 @@ void qmp_block_job_cancel(const char *device,
         force = false;
     }
 
-    if (job->paused && !force) {
+    if (job->user_paused && !force) {
         error_setg(errp, "The block job for device '%s' is currently paused",
                    device);
         goto out;
@@ -2500,13 +2885,13 @@ out:
 void qmp_block_job_pause(const char *device, Error **errp)
 {
     AioContext *aio_context;
-    BlockJob *job = find_block_job(device, &aio_context);
+    BlockJob *job = find_block_job(device, &aio_context, errp);
 
-    if (!job) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
+    if (!job || job->user_paused) {
         return;
     }
 
+    job->user_paused = true;
     trace_qmp_block_job_pause(job);
     block_job_pause(job);
     aio_context_release(aio_context);
@@ -2515,13 +2900,13 @@ void qmp_block_job_pause(const char *device, Error **errp)
 void qmp_block_job_resume(const char *device, Error **errp)
 {
     AioContext *aio_context;
-    BlockJob *job = find_block_job(device, &aio_context);
+    BlockJob *job = find_block_job(device, &aio_context, errp);
 
-    if (!job) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
+    if (!job || !job->user_paused) {
         return;
     }
 
+    job->user_paused = false;
     trace_qmp_block_job_resume(job);
     block_job_resume(job);
     aio_context_release(aio_context);
@@ -2530,10 +2915,9 @@ void qmp_block_job_resume(const char *device, Error **errp)
 void qmp_block_job_complete(const char *device, Error **errp)
 {
     AioContext *aio_context;
-    BlockJob *job = find_block_job(device, &aio_context);
+    BlockJob *job = find_block_job(device, &aio_context, errp);
 
     if (!job) {
-        error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
         return;
     }
 
@@ -2547,48 +2931,53 @@ void qmp_change_backing_file(const char *device,
                              const char *backing_file,
                              Error **errp)
 {
+    BlockBackend *blk;
     BlockDriverState *bs = NULL;
+    AioContext *aio_context;
     BlockDriverState *image_bs = NULL;
     Error *local_err = NULL;
     bool ro;
     int open_flags;
     int ret;
 
-    /* find the top layer BDS of the chain */
-    bs = bdrv_find(device);
-    if (!bs) {
+    blk = blk_by_name(device);
+    if (!blk) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    bs = blk_bs(blk);
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
 
     image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
 
     if (!image_bs) {
         error_setg(errp, "image file not found");
-        return;
+        goto out;
     }
 
     if (bdrv_find_base(image_bs) == image_bs) {
         error_setg(errp, "not allowing backing file change on an image "
                          "without a backing file");
-        return;
+        goto out;
     }
 
     /* even though we are not necessarily operating on bs, we need it to
      * determine if block ops are currently prohibited on the chain */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
-        return;
+        goto out;
     }
 
     /* final sanity check */
     if (!bdrv_chain_contains(bs, image_bs)) {
         error_setg(errp, "'%s' and image file are not in the same chain",
                    device);
-        return;
+        goto out;
     }
 
     /* if not r/w, reopen to make r/w */
@@ -2599,7 +2988,7 @@ void qmp_change_backing_file(const char *device,
         bdrv_reopen(image_bs, open_flags | BDRV_O_RDWR, &local_err);
         if (local_err) {
             error_propagate(errp, local_err);
-            return;
+            goto out;
         }
     }
 
@@ -2619,6 +3008,9 @@ void qmp_change_backing_file(const char *device,
             error_propagate(errp, local_err); /* will preserve prior errp */
         }
     }
+
+out:
+    aio_context_release(aio_context);
 }
 
 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)