diff --git a/src/libvirt.c b/src/libvirt.c
index ae8c9fddec..53b485a9f6 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -17102,10 +17102,13 @@ virDomainSnapshotGetConnect(virDomainSnapshotPtr snapshot)
  * VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY to be passed as well.
  *
  * By default, if the snapshot involves external files, and any of the
- * destination files already exist as a regular file, the snapshot is
- * rejected to avoid losing contents of those files.  However, if
- * @flags includes VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT, then existing
- * destination files are instead truncated and reused.
+ * destination files already exist as a non-empty regular file, the
+ * snapshot is rejected to avoid losing contents of those files.
+ * However, if @flags includes VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT,
+ * then the destination files must already exist and contain content
+ * identical to the source files (this allows a management app to
+ * pre-create files with relative backing file names, rather than the
+ * default of creating with absolute backing file names).
  *
  * Be aware that although libvirt prefers to report errors up front with
  * no other effect, some hypervisors have certain types of failures where
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 76cb58a96b..3a8317fbcf 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9726,6 +9726,12 @@ qemuDomainSnapshotDiskPrepare(virDomainObjPtr vm, virDomainSnapshotDefPtr def,
     int external = 0;
     qemuDomainObjPrivatePtr priv = vm->privateData;
 
+    if (allow_reuse && !qemuCapsGet(priv->qemuCaps, QEMU_CAPS_TRANSACTION)) {
+        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                        _("reuse is not supported with this QEMU binary"));
+        goto cleanup;
+    }
+
     for (i = 0; i < def->ndisks; i++) {
         virDomainSnapshotDiskDefPtr disk = &def->disks[i];
 
@@ -9756,8 +9762,8 @@ qemuDomainSnapshotDiskPrepare(virDomainObjPtr vm, virDomainSnapshotDefPtr def,
                     virReportOOMError();
                     goto cleanup;
                 }
-            } else if (STRNEQ(disk->driverType, "qcow2")) {
-                /* XXX We should also support QED */
+            } else if (STRNEQ(disk->driverType, "qcow2") &&
+                       STRNEQ(disk->driverType, "qed")) {
                 qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                 _("external snapshot format for disk %s "
                                   "is unsupported: %s"),
@@ -9771,7 +9777,7 @@ qemuDomainSnapshotDiskPrepare(virDomainObjPtr vm, virDomainSnapshotDefPtr def,
                                          disk->name, disk->file);
                     goto cleanup;
                 }
-            } else if (!(S_ISBLK(st.st_mode) || allow_reuse)) {
+            } else if (!(S_ISBLK(st.st_mode) || !st.st_size || allow_reuse)) {
                 qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                 _("external snapshot file for disk %s already "
                                   "exists and is not a block device: %s"),
@@ -9824,7 +9830,8 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver *driver,
                                          virDomainSnapshotDiskDefPtr snap,
                                          virDomainDiskDefPtr disk,
                                          virDomainDiskDefPtr persistDisk,
-                                         virJSONValuePtr actions)
+                                         virJSONValuePtr actions,
+                                         bool reuse)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
     char *device = NULL;
@@ -9846,23 +9853,25 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver *driver,
 
     if (virAsprintf(&device, "drive-%s", disk->info.alias) < 0 ||
         !(source = strdup(snap->file)) ||
-        (STRNEQ_NULLABLE(disk->driverType, "qcow2") &&
-         !(driverType = strdup("qcow2"))) ||
+        (STRNEQ_NULLABLE(disk->driverType, snap->driverType) &&
+         !(driverType = strdup(snap->driverType))) ||
         (persistDisk &&
          (!(persistSource = strdup(source)) ||
-          (STRNEQ_NULLABLE(persistDisk->driverType, "qcow2") &&
-           !(persistDriverType = strdup("qcow2")))))) {
+          (STRNEQ_NULLABLE(persistDisk->driverType, snap->driverType) &&
+           !(persistDriverType = strdup(snap->driverType)))))) {
         virReportOOMError();
         goto cleanup;
     }
 
     /* create the stub file and set selinux labels; manipulate disk in
      * place, in a way that can be reverted on failure. */
-    fd = qemuOpenFile(driver, source, O_WRONLY | O_TRUNC | O_CREAT,
-                      &need_unlink, NULL);
-    if (fd < 0)
-        goto cleanup;
-    VIR_FORCE_CLOSE(fd);
+    if (!reuse) {
+        fd = qemuOpenFile(driver, source, O_WRONLY | O_TRUNC | O_CREAT,
+                          &need_unlink, NULL);
+        if (fd < 0)
+            goto cleanup;
+        VIR_FORCE_CLOSE(fd);
+    }
 
     origsrc = disk->src;
     disk->src = source;
@@ -9884,7 +9893,8 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver *driver,
     origdriver = NULL;
 
     /* create the actual snapshot */
-    ret = qemuMonitorDiskSnapshot(priv->mon, actions, device, source);
+    ret = qemuMonitorDiskSnapshot(priv->mon, actions, device, source,
+                                  driverType, reuse);
     virDomainAuditDisk(vm, disk->src, source, "snapshot", ret >= 0);
     if (ret < 0)
         goto cleanup;
@@ -10005,6 +10015,7 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
     bool persist = false;
     int thaw = 0; /* 1 if freeze succeeded, -1 if freeze failed */
     bool atomic = (flags & VIR_DOMAIN_SNAPSHOT_CREATE_ATOMIC) != 0;
+    bool reuse = (flags & VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT) != 0;
 
     if (qemuDomainObjBeginJobWithDriver(driver, vm, QEMU_JOB_MODIFY) < 0)
         return -1;
@@ -10080,7 +10091,8 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
         ret = qemuDomainSnapshotCreateSingleDiskActive(driver, vm,
                                                        &snap->def->disks[i],
                                                        vm->def->disks[i],
-                                                       persistDisk, actions);
+                                                       persistDisk, actions,
+                                                       reuse);
         if (ret < 0)
             break;
     }
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 9a13e201f6..e1a8d4c9c6 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -2657,12 +2657,13 @@ int qemuMonitorDeleteSnapshot(qemuMonitorPtr mon, const char *name)
  * at file.  */
 int
 qemuMonitorDiskSnapshot(qemuMonitorPtr mon, virJSONValuePtr actions,
-                        const char *device, const char *file)
+                        const char *device, const char *file,
+                        const char *format, bool reuse)
 {
     int ret;
 
-    VIR_DEBUG("mon=%p, actions=%p, device=%s, file=%s",
-              mon, actions, device, file);
+    VIR_DEBUG("mon=%p, actions=%p, device=%s, file=%s, format=%s, reuse=%d",
+              mon, actions, device, file, format, reuse);
 
     if (!mon) {
         qemuReportError(VIR_ERR_INVALID_ARG, "%s",
@@ -2671,11 +2672,12 @@ qemuMonitorDiskSnapshot(qemuMonitorPtr mon, virJSONValuePtr actions,
     }
 
     if (mon->json) {
-        ret = qemuMonitorJSONDiskSnapshot(mon, actions, device, file);
+        ret = qemuMonitorJSONDiskSnapshot(mon, actions, device, file, format,
+                                          reuse);
     } else {
-        if (actions) {
+        if (actions || STRNEQ(format, "qcow2") || reuse) {
             qemuReportError(VIR_ERR_INVALID_ARG, "%s",
-                            _("actions not supported with text monitor"));
+                            _("text monitor lacks several snapshot features"));
             return -1;
         }
         ret = qemuMonitorTextDiskSnapshot(mon, device, file);
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index 5ee108349f..b48096661a 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -505,7 +505,9 @@ int qemuMonitorDeleteSnapshot(qemuMonitorPtr mon, const char *name);
 int qemuMonitorDiskSnapshot(qemuMonitorPtr mon,
                             virJSONValuePtr actions,
                             const char *device,
-                            const char *file);
+                            const char *file,
+                            const char *format,
+                            bool reuse);
 int qemuMonitorTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index a0d6a1be07..eeeb6a603b 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -3105,7 +3105,8 @@ cleanup:
 
 int
 qemuMonitorJSONDiskSnapshot(qemuMonitorPtr mon, virJSONValuePtr actions,
-                            const char *device, const char *file)
+                            const char *device, const char *file,
+                            const char *format, bool reuse)
 {
     int ret;
     virJSONValuePtr cmd;
@@ -3115,6 +3116,9 @@ qemuMonitorJSONDiskSnapshot(qemuMonitorPtr mon, virJSONValuePtr actions,
                                         "blockdev-snapshot-sync",
                                         "s:device", device,
                                         "s:snapshot-file", file,
+                                        "s:format", format,
+                                        reuse ? "s:mode" : NULL,
+                                        reuse ? "existing" : NULL,
                                         NULL);
     if (!cmd)
         return -1;
diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
index e127870b48..a0f67aaba1 100644
--- a/src/qemu/qemu_monitor_json.h
+++ b/src/qemu/qemu_monitor_json.h
@@ -228,7 +228,9 @@ int qemuMonitorJSONDeleteSnapshot(qemuMonitorPtr mon, const char *name);
 int qemuMonitorJSONDiskSnapshot(qemuMonitorPtr mon,
                                 virJSONValuePtr actions,
                                 const char *device,
-                                const char *file);
+                                const char *file,
+                                const char *format,
+                                bool reuse);
 int qemuMonitorJSONTransaction(qemuMonitorPtr mon, virJSONValuePtr actions);
 
 int qemuMonitorJSONArbitraryCommand(qemuMonitorPtr mon,