diff --git a/blockdev.c b/blockdev.c
index 3c8d994..3b598f8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1606,7 +1606,6 @@
     BlkActionState common;
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
-    AioContext *aio_context;
     bool overlay_appended;
 } ExternalSnapshotState;
 
@@ -1626,6 +1625,7 @@
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
     TransactionAction *action = common->action;
+    AioContext *aio_context;
 
     /* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar
      * purpose but a different set of parameters */
@@ -1662,31 +1662,32 @@
         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);
+    aio_context = bdrv_get_aio_context(state->old_bs);
+    aio_context_acquire(aio_context);
+
+    /* Paired with .clean() */
     bdrv_drained_begin(state->old_bs);
 
     if (!bdrv_is_inserted(state->old_bs)) {
         error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        return;
+        goto out;
     }
 
     if (bdrv_op_is_blocked(state->old_bs,
                            BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, errp)) {
-        return;
+        goto out;
     }
 
     if (!bdrv_is_read_only(state->old_bs)) {
         if (bdrv_flush(state->old_bs)) {
             error_setg(errp, QERR_IO_ERROR);
-            return;
+            goto out;
         }
     }
 
     if (!bdrv_is_first_non_filter(state->old_bs)) {
         error_setg(errp, QERR_FEATURE_DISABLED, "snapshot");
-        return;
+        goto out;
     }
 
     if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) {
@@ -1698,13 +1699,13 @@
 
         if (node_name && !snapshot_node_name) {
             error_setg(errp, "New snapshot node name missing");
-            return;
+            goto out;
         }
 
         if (snapshot_node_name &&
             bdrv_lookup_bs(snapshot_node_name, snapshot_node_name, NULL)) {
             error_setg(errp, "New snapshot node name already in use");
-            return;
+            goto out;
         }
 
         flags = state->old_bs->open_flags;
@@ -1717,7 +1718,7 @@
             int64_t size = bdrv_getlength(state->old_bs);
             if (size < 0) {
                 error_setg_errno(errp, -size, "bdrv_getlength failed");
-                return;
+                goto out;
             }
             bdrv_img_create(new_image_file, format,
                             state->old_bs->filename,
@@ -1725,7 +1726,7 @@
                             NULL, size, flags, false, &local_err);
             if (local_err) {
                 error_propagate(errp, local_err);
-                return;
+                goto out;
             }
         }
 
@@ -1740,30 +1741,30 @@
                               errp);
     /* We will manually add the backing_hd field to the bs later */
     if (!state->new_bs) {
-        return;
+        goto out;
     }
 
     if (bdrv_has_blk(state->new_bs)) {
         error_setg(errp, "The snapshot is already in use");
-        return;
+        goto out;
     }
 
     if (bdrv_op_is_blocked(state->new_bs, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
                            errp)) {
-        return;
+        goto out;
     }
 
     if (state->new_bs->backing != NULL) {
         error_setg(errp, "The snapshot already has a backing image");
-        return;
+        goto out;
     }
 
     if (!state->new_bs->drv->supports_backing) {
         error_setg(errp, "The snapshot does not support backing images");
-        return;
+        goto out;
     }
 
-    bdrv_set_aio_context(state->new_bs, state->aio_context);
+    bdrv_set_aio_context(state->new_bs, aio_context);
 
     /* This removes our old bs and adds the new bs. This is an operation that
      * can fail, so we need to do it in .prepare; undoing it for abort is
@@ -1772,15 +1773,22 @@
     bdrv_append(state->new_bs, state->old_bs, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
     state->overlay_appended = true;
+
+out:
+    aio_context_release(aio_context);
 }
 
 static void external_snapshot_commit(BlkActionState *common)
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
+    AioContext *aio_context;
+
+    aio_context = bdrv_get_aio_context(state->old_bs);
+    aio_context_acquire(aio_context);
 
     /* We don't need (or want) to use the transactional
      * bdrv_reopen_multiple() across all the entries at once, because we
@@ -1789,6 +1797,8 @@
         bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR,
                     NULL);
     }
+
+    aio_context_release(aio_context);
 }
 
 static void external_snapshot_abort(BlkActionState *common)
@@ -1797,11 +1807,18 @@
                              DO_UPCAST(ExternalSnapshotState, common, common);
     if (state->new_bs) {
         if (state->overlay_appended) {
+            AioContext *aio_context;
+
+            aio_context = bdrv_get_aio_context(state->old_bs);
+            aio_context_acquire(aio_context);
+
             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);
             bdrv_replace_node(state->new_bs, state->old_bs, &error_abort);
             bdrv_unref(state->old_bs); /* bdrv_replace_node() ref'ed old_bs */
+
+            aio_context_release(aio_context);
         }
     }
 }
@@ -1810,11 +1827,19 @@
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
-    if (state->aio_context) {
-        bdrv_drained_end(state->old_bs);
-        bdrv_unref(state->new_bs);
-        aio_context_release(state->aio_context);
+    AioContext *aio_context;
+
+    if (!state->old_bs) {
+        return;
     }
+
+    aio_context = bdrv_get_aio_context(state->old_bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_drained_end(state->old_bs);
+    bdrv_unref(state->new_bs);
+
+    aio_context_release(aio_context);
 }
 
 typedef struct DriveBackupState {