[Qemu-devel] [PATCH v3 2/8] nbd: Forbid nbd-server-stop when server is not running

[Eric Blake <eblake@redhat.com>]

Since we already forbid other nbd-server commands when not
in the right state, it is unlikely that any caller was relying
on a second stop to behave as a silent no-op.  Update iotest
223 to show the improved behavior.

Signed-off-by: Eric Blake <eblake@redhat.com>

---
v3: new patch
---
 blockdev-nbd.c             | 5 +++++
 tests/qemu-iotests/223     | 2 +-
 tests/qemu-iotests/223.out | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 1d170c80b82..ca584919194 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -214,6 +214,11 @@ void qmp_nbd_server_remove(const char *name,

 void qmp_nbd_server_stop(Error **errp)
 {
+    if (!nbd_server) {
+        error_setg(errp, "NBD server not running");
+        return;
+    }
+
     nbd_export_close_all();

     nbd_server_free(nbd_server);
diff --git a/tests/qemu-iotests/223 b/tests/qemu-iotests/223
index 61b46a2f066..a4016091b21 100755
--- a/tests/qemu-iotests/223
+++ b/tests/qemu-iotests/223
@@ -172,7 +172,7 @@ _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-remove",
   "arguments":{"name":"n2"}}' "error" # Attempt duplicate clean
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return"
-_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "return" # Oops
+_send_qemu_cmd $QEMU_HANDLE '{"execute":"nbd-server-stop"}' "error" # Again
 _send_qemu_cmd $QEMU_HANDLE '{"execute":"quit"}' "return"

 # success, all done
diff --git a/tests/qemu-iotests/223.out b/tests/qemu-iotests/223.out
index e6ede0591cd..8a4d63a4fc2 100644
--- a/tests/qemu-iotests/223.out
+++ b/tests/qemu-iotests/223.out
@@ -69,6 +69,6 @@ read 2097152/2097152 bytes at offset 2097152
 {"return": {}}
 {"error": {"class": "GenericError", "desc": "Export 'n2' is not found"}}
 {"return": {}}
-{"return": {}}
+{"error": {"class": "GenericError", "desc": "NBD server not running"}}
 {"return": {}}
 *** done
-- 
2.20.1