blockdev: Add blockdev-insert-medium

And a helper function for that, which directly takes a pointer to the
BDS to be inserted instead of its node-name (which will be used for
implementing 'change' using blockdev-insert-medium).
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

blockdev.c

@@ -2198,6 +2198,62 @@ out:
     aio_context_release(aio_context);
 }
 
+static void qmp_blockdev_insert_anon_medium(const char *device,
+                                            BlockDriverState *bs, Error **errp)
+{
+    BlockBackend *blk;
+    bool has_device;
+
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", device);
+        return;
+    }
+
+    /* For BBs without a device, we can exchange the BDS tree at will */
+    has_device = blk_get_attached_dev(blk);
+
+    if (has_device && !blk_dev_has_removable_media(blk)) {
+        error_setg(errp, "Device '%s' is not removable", device);
+        return;
+    }
+
+    if (has_device && !blk_dev_is_tray_open(blk)) {
+        error_setg(errp, "Tray of device '%s' is not open", device);
+        return;
+    }
+
+    if (blk_bs(blk)) {
+        error_setg(errp, "There already is a medium in device '%s'", device);
+        return;
+    }
+
+    blk_insert_bs(blk, bs);
+
+    QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list);
+}
+
+void qmp_blockdev_insert_medium(const char *device, const char *node_name,
+                                Error **errp)
+{
+    BlockDriverState *bs;
+
+    bs = bdrv_find_node(node_name);
+    if (!bs) {
+        error_setg(errp, "Node '%s' not found", node_name);
+        return;
+    }
+
+    if (bs->blk) {
+        error_setg(errp, "Node '%s' is already in use by '%s'", node_name,
+                   blk_name(bs->blk));
+        return;
+    }
+
+    qmp_blockdev_insert_anon_medium(device, bs, errp);
+}
+
 /* throttling disk I/O limits */
 void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
                                int64_t bps_wr,

qapi/block-core.json

@@ -1940,6 +1940,23 @@
 { 'command': 'blockdev-remove-medium',
   'data': { 'device': 'str' } }
 
+##
+# @blockdev-insert-medium:
+#
+# Inserts a medium (a block driver state tree) into a block device. That block
+# device's tray must currently be open (unless there is no attached guest
+# device) and there must be no medium inserted already.
+#
+# @device:    block device name
+#
+# @node-name: name of a node in the block driver state graph
+#
+# Since: 2.5
+##
+{ 'command': 'blockdev-insert-medium',
+  'data': { 'device': 'str',
+            'node-name': 'str'} }
+
 
 ##
 # @BlockErrorAction

qmp-commands.hx

@@ -4080,6 +4080,43 @@ Example:
 
 <- { "return": {} }
 
+EQMP
+
+    {
+        .name       = "blockdev-insert-medium",
+        .args_type  = "device:s,node-name:s",
+        .mhandler.cmd_new = qmp_marshal_blockdev_insert_medium,
+    },
+
+SQMP
+blockdev-insert-medium
+----------------------
+
+Inserts a medium (a block driver state tree) into a block device. That block
+device's tray must currently be open (unless there is no attached guest device)
+and there must be no medium inserted already.
+
+Arguments:
+
+- "device": block device name (json-string)
+- "node-name": root node of the BDS tree to insert into the block device
+
+Example:
+
+-> { "execute": "blockdev-add",
+     "arguments": { "options": { "node-name": "node0",
+                                 "driver": "raw",
+                                 "file": { "driver": "file",
+                                           "filename": "fedora.iso" } } } }
+
+<- { "return": {} }
+
+-> { "execute": "blockdev-insert-medium",
+     "arguments": { "device": "ide1-cd0",
+                    "node-name": "node0" } }
+
+<- { "return": {} }
+
 EQMP
 
     {