[Qemu-devel] [RFC PATCH 5/7] block: Accept device model name for blockdev-open/close-tray

[Kevin Wolf <kwolf@redhat.com>]

This is an example conversion of a QMP command that operates on the
BlockBackend level to accept both the device model name (which is
supposed to become the primary interface) and the BlockBackend name.

Naming suggestions for the new QMP field are welcome. The obvious one
would be "device", but that's already taken...

We'll also want QAPI to understand that exactly one of the two fields
must be given, so we can remove/don't have to add explicit code in the
command implementations to check that.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c           | 60 +++++++++++++++++++++++++++++++++++++++-------------
 qapi/block-core.json | 14 ++++++++----
 qmp-commands.hx      | 12 +++++++----
 3 files changed, 63 insertions(+), 23 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 3a104a0..24c4d0a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -56,7 +56,8 @@
 static QTAILQ_HEAD(, BlockDriverState) monitor_bdrv_states =
     QTAILQ_HEAD_INITIALIZER(monitor_bdrv_states);
 
-static int do_open_tray(const char *device, bool force, Error **errp);
+static int do_open_tray(const char *blk_name, const char *qdev_id,
+                        bool force, Error **errp);
 
 static const char *const if_name[IF_COUNT] = {
     [IF_NONE] = "none",
@@ -1172,6 +1173,29 @@ fail:
     return dinfo;
 }
 
+static BlockBackend *qmp_get_blk(const char *blk_name, const char *qdev_id,
+                                 Error **errp)
+{
+    BlockBackend *blk;
+
+    if (!blk_name == !qdev_id) {
+        error_setg(errp, "Need exactly one of 'device' and 'id'");
+        return NULL;
+    }
+
+    if (qdev_id) {
+        blk = blk_by_qdev_id(qdev_id, errp);
+    } else {
+        blk = blk_by_name(blk_name);
+        if (blk == NULL) {
+            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                      "Device '%s' not found", blk_name);
+        }
+    }
+
+    return blk;
+}
+
 void hmp_commit(Monitor *mon, const QDict *qdict)
 {
     const char *device = qdict_get_str(qdict, "device");
@@ -2285,7 +2309,7 @@ void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
         force = false;
     }
 
-    rc = do_open_tray(device, force, &local_err);
+    rc = do_open_tray(device, NULL, force, &local_err);
     if (rc && rc != -ENOSYS) {
         error_propagate(errp, local_err);
         return;
@@ -2330,15 +2354,15 @@ void qmp_block_passwd(bool has_device, const char *device,
  * If the guest was asked to open the tray, return -EINPROGRESS.
  * Else, return 0.
  */
-static int do_open_tray(const char *device, bool force, Error **errp)
+static int do_open_tray(const char *blk_name, const char *qdev_id,
+                        bool force, Error **errp)
 {
     BlockBackend *blk;
+    const char *device = qdev_id ?: blk_name;
     bool locked;
 
-    blk = blk_by_name(device);
+    blk = qmp_get_blk(blk_name, qdev_id, errp);
     if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
         return -ENODEV;
     }
 
@@ -2374,7 +2398,9 @@ static int do_open_tray(const char *device, bool force, Error **errp)
     return 0;
 }
 
-void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
+void qmp_blockdev_open_tray(bool has_device, const char *device,
+                            bool has_id, const char *id,
+                            bool has_force, bool force,
                             Error **errp)
 {
     Error *local_err = NULL;
@@ -2383,7 +2409,9 @@ void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
     if (!has_force) {
         force = false;
     }
-    rc = do_open_tray(device, force, &local_err);
+    rc = do_open_tray(has_device ? device : NULL,
+                      has_id ? id : NULL,
+                      force, &local_err);
     if (rc && rc != -ENOSYS && rc != -EINPROGRESS) {
         error_propagate(errp, local_err);
         return;
@@ -2391,19 +2419,21 @@ void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
     error_free(local_err);
 }
 
-void qmp_blockdev_close_tray(const char *device, Error **errp)
+void qmp_blockdev_close_tray(bool has_device, const char *device,
+                             bool has_id, const char *id,
+                             Error **errp)
 {
     BlockBackend *blk;
 
-    blk = blk_by_name(device);
+    blk = qmp_get_blk(has_device ? device : NULL,
+                      has_id ? id : NULL,
+                      errp);
     if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
         return;
     }
 
     if (!blk_dev_has_removable_media(blk)) {
-        error_setg(errp, "Device '%s' is not removable", device);
+        error_setg(errp, "Device '%s' is not removable", device ?: id);
         return;
     }
 
@@ -2599,7 +2629,7 @@ void qmp_blockdev_change_medium(const char *device, const char *filename,
         goto fail;
     }
 
-    rc = do_open_tray(device, false, &err);
+    rc = do_open_tray(device, NULL, false, &err);
     if (rc && rc != -ENOSYS) {
         error_propagate(errp, err);
         goto fail;
@@ -2621,7 +2651,7 @@ void qmp_blockdev_change_medium(const char *device, const char *filename,
 
     blk_apply_root_state(blk, medium_bs);
 
-    qmp_blockdev_close_tray(device, errp);
+    qmp_blockdev_close_tray(true, device, false, NULL, errp);
 
 fail:
     /* If the medium has been inserted, the device has its own reference, so
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 98a20d2..15669b3 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2201,7 +2201,9 @@
 #   to it
 # - if the guest device does not have an actual tray
 #
-# @device: block device name
+# @device:  block device name (deprecated, use @id instead)
+#
+# @id:      the name or QOM path of the guest device
 #
 # @force:  #optional if false (the default), an eject request will be sent to
 #          the guest if it has locked the tray (and the tray will not be opened
@@ -2211,7 +2213,8 @@
 # Since: 2.5
 ##
 { 'command': 'blockdev-open-tray',
-  'data': { 'device': 'str',
+  'data': { '*device': 'str',
+            '*id': 'str',
             '*force': 'bool' } }
 
 ##
@@ -2223,12 +2226,15 @@
 #
 # If the tray was already closed before, this will be a no-op.
 #
-# @device: block device name
+# @device:  block device name (deprecated, use @id instead)
+#
+# @id:      the name or QOM path of the guest device
 #
 # Since: 2.5
 ##
 { 'command': 'blockdev-close-tray',
-  'data': { 'device': 'str' } }
+  'data': { '*device': 'str',
+            '*id': 'str' } }
 
 ##
 # @x-blockdev-remove-medium:
diff --git a/qmp-commands.hx b/qmp-commands.hx
index b444c20..ae0105f 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -4255,7 +4255,7 @@ EQMP
 
     {
         .name       = "blockdev-open-tray",
-        .args_type  = "device:s,force:b?",
+        .args_type  = "device:s?,id:s?,force:b?",
         .mhandler.cmd_new = qmp_marshal_blockdev_open_tray,
     },
 
@@ -4280,7 +4280,9 @@ which no such event will be generated, these include:
 
 Arguments:
 
-- "device": block device name (json-string)
+- "device": block device name (deprecated, use @id instead)
+            (json-string, optional)
+- "id": the name or QOM path of the guest device (json-string, optional)
 - "force": if false (the default), an eject request will be sent to the guest if
            it has locked the tray (and the tray will not be opened immediately);
            if true, the tray will be opened regardless of whether it is locked
@@ -4303,7 +4305,7 @@ EQMP
 
     {
         .name       = "blockdev-close-tray",
-        .args_type  = "device:s",
+        .args_type  = "device:s?,id:s?",
         .mhandler.cmd_new = qmp_marshal_blockdev_close_tray,
     },
 
@@ -4319,7 +4321,9 @@ If the tray was already closed before, this will be a no-op.
 
 Arguments:
 
-- "device": block device name (json-string)
+- "device": block device name (deprecated, use @id instead)
+            (json-string, optional)
+- "id": the name or QOM path of the guest device (json-string, optional)
 
 Example:
 
-- 
1.8.3.1