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

Block layer patches:

- hmp: Fix drive_add ... format=help crash
- block: Forward 'discard' to temporary overlay

# gpg: Signature made Mon 08 Apr 2019 16:43:20 BST
# 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:
  hmp: Fix drive_add ... format=help crash
  block: Forward 'discard' to temporary overlay
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

block.c

@@ -950,8 +950,9 @@ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
     qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
     qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
 
-    /* Copy the read-only option from the parent */
+    /* Copy the read-only and discard options from the parent */
     qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_DISCARD);
 
     /* aio=native doesn't work for cache.direct=off, so disable it for the
      * temporary snapshot */

device-hotplug.c

@@ -48,7 +48,7 @@ static DriveInfo *add_init_drive(const char *optstr)
 
     mc = MACHINE_GET_CLASS(current_machine);
     dinfo = drive_new(opts, mc->block_default_type, &err);
-    if (!dinfo) {
+    if (err) {
         error_report_err(err);
         qemu_opts_del(opts);
         return NULL;

tests/test-hmp.c

@@ -31,6 +31,7 @@ static const char *hmp_cmds[] = {
     "cpu 0",
     "device_add ?",
     "device_add usb-mouse,id=mouse1",
+    "drive_add ignored format=help",
     "mouse_button 7",
     "mouse_move 10 10",
     "mouse_button 0",