[Qemu-devel] [PATCH v3 12/12] block: Remove BB interface from blockdev-add/del

[Kevin Wolf <kwolf@redhat.com>]

With this patch, blockdev-add always works on a node level, i.e. it
creates a BDS, but no BB. Consequently, x-blockdev-del doesn't need the
'device' option any more, but 'node-name' becomes mandatory.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c            | 124 ++++++++++++++------------------------------------
 docs/qmp-commands.txt |  24 +++-------
 qapi/block-core.json  |  30 +++---------
 3 files changed, 47 insertions(+), 131 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 17c2671..29c6561 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2844,7 +2844,7 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
 
     bs = bdrv_find_node(id);
     if (bs) {
-        qmp_x_blockdev_del(false, NULL, true, id, &local_err);
+        qmp_x_blockdev_del(id, &local_err);
         if (local_err) {
             error_report_err(local_err);
         }
@@ -3827,7 +3827,6 @@ out:
 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 {
     BlockDriverState *bs;
-    BlockBackend *blk = NULL;
     QObject *obj;
     Visitor *v = qmp_output_visitor_new(&obj);
     QDict *qdict;
@@ -3859,37 +3858,21 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 
     qdict_flatten(qdict);
 
-    if (options->has_id) {
-        blk = blockdev_init(NULL, qdict, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
-            goto fail;
-        }
-
-        bs = blk_bs(blk);
-    } else {
-        if (!qdict_get_try_str(qdict, "node-name")) {
-            error_setg(errp, "'id' and/or 'node-name' need to be specified for "
-                       "the root node");
-            goto fail;
-        }
-
-        bs = bds_tree_init(qdict, errp);
-        if (!bs) {
-            goto fail;
-        }
+    if (!qdict_get_try_str(qdict, "node-name")) {
+        error_setg(errp, "'node-name' must be specified for the root node");
+        goto fail;
+    }
 
-        QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
+    bs = bds_tree_init(qdict, errp);
+    if (!bs) {
+        goto fail;
     }
 
+    QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
+
     if (bs && bdrv_key_required(bs)) {
-        if (blk) {
-            monitor_remove_blk(blk);
-            blk_unref(blk);
-        } else {
-            QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
-            bdrv_unref(bs);
-        }
+        QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
+        bdrv_unref(bs);
         error_setg(errp, "blockdev-add doesn't support encrypted devices");
         goto fail;
     }
@@ -3898,81 +3881,42 @@ fail:
     visit_free(v);
 }
 
-void qmp_x_blockdev_del(bool has_id, const char *id,
-                        bool has_node_name, const char *node_name, Error **errp)
+void qmp_x_blockdev_del(const char *node_name, Error **errp)
 {
     AioContext *aio_context;
-    BlockBackend *blk;
     BlockDriverState *bs;
 
-    if (has_id && has_node_name) {
-        error_setg(errp, "Only one of id and node-name must be specified");
-        return;
-    } else if (!has_id && !has_node_name) {
-        error_setg(errp, "No block device specified");
+    bs = bdrv_find_node(node_name);
+    if (!bs) {
+        error_setg(errp, "Cannot find node %s", node_name);
         return;
     }
-
-    if (has_id) {
-        /* blk_by_name() never returns a BB that is not owned by the monitor */
-        blk = blk_by_name(id);
-        if (!blk) {
-            error_setg(errp, "Cannot find block backend %s", id);
-            return;
-        }
-        if (blk_legacy_dinfo(blk)) {
-            error_setg(errp, "Deleting block backend added with drive-add"
-                       " is not supported");
-            return;
-        }
-        if (blk_get_refcnt(blk) > 1) {
-            error_setg(errp, "Block backend %s is in use", id);
-            return;
-        }
-        bs = blk_bs(blk);
-        aio_context = blk_get_aio_context(blk);
-    } else {
-        blk = NULL;
-        bs = bdrv_find_node(node_name);
-        if (!bs) {
-            error_setg(errp, "Cannot find node %s", node_name);
-            return;
-        }
-        if (bdrv_has_blk(bs)) {
-            error_setg(errp, "Node %s is in use", node_name);
-            return;
-        }
-        aio_context = bdrv_get_aio_context(bs);
+    if (bdrv_has_blk(bs)) {
+        error_setg(errp, "Node %s is in use", node_name);
+        return;
     }
-
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (bs) {
-        if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, errp)) {
-            goto out;
-        }
-
-        if (!blk && !QTAILQ_IN_USE(bs, monitor_list)) {
-            error_setg(errp, "Node %s is not owned by the monitor",
-                       bs->node_name);
-            goto out;
-        }
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, errp)) {
+        goto out;
+    }
 
-        if (bs->refcnt > 1) {
-            error_setg(errp, "Block device %s is in use",
-                       bdrv_get_device_or_node_name(bs));
-            goto out;
-        }
+    if (!bs->monitor_list.tqe_prev) {
+        error_setg(errp, "Node %s is not owned by the monitor",
+                   bs->node_name);
+        goto out;
     }
 
-    if (blk) {
-        monitor_remove_blk(blk);
-        blk_unref(blk);
-    } else {
-        QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
-        bdrv_unref(bs);
+    if (bs->refcnt > 1) {
+        error_setg(errp, "Block device %s is in use",
+                   bdrv_get_device_or_node_name(bs));
+        goto out;
     }
 
+    QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
+    bdrv_unref(bs);
+
 out:
     aio_context_release(aio_context);
 }
diff --git a/docs/qmp-commands.txt b/docs/qmp-commands.txt
index 41f5698..e0adceb 100644
--- a/docs/qmp-commands.txt
+++ b/docs/qmp-commands.txt
@@ -3141,7 +3141,7 @@ Example (2):
      "arguments": {
          "options": {
            "driver": "qcow2",
-           "id": "my_disk",
+           "node-name": "my_disk",
            "discard": "unmap",
            "cache": {
                "direct": true,
@@ -3168,18 +3168,9 @@ x-blockdev-del
 ------------
 Since 2.5
 
-Deletes a block device thas has been added using blockdev-add.
-The selected device can be either a block backend or a graph node.
-
-In the former case the backend will be destroyed, along with its
-inserted medium if there's any. The command will fail if the backend
-or its medium are in use.
-
-In the latter case the node will be destroyed. The command will fail
-if the node is attached to a block backend or is otherwise being
-used.
-
-One of "id" or "node-name" must be specified, but not both.
+Deletes a block device that has been added using blockdev-add.
+The command will fail if the node is attached to a device or is
+otherwise being used.
 
 This command is still a work in progress and is considered
 experimental. Stay away from it unless you want to help with its
@@ -3187,8 +3178,7 @@ development.
 
 Arguments:
 
-- "id": Name of the block backend device to delete (json-string, optional)
-- "node-name": Name of the graph node to delete (json-string, optional)
+- "node-name": Name of the graph node to delete (json-string)
 
 Example:
 
@@ -3196,7 +3186,7 @@ Example:
      "arguments": {
          "options": {
              "driver": "qcow2",
-             "id": "drive0",
+             "node-name": "node0",
              "file": {
                  "driver": "file",
                  "filename": "test.qcow2"
@@ -3208,7 +3198,7 @@ Example:
 <- { "return": {} }
 
 -> { "execute": "x-blockdev-del",
-     "arguments": { "id": "drive0" }
+     "arguments": { "node-name": "node0" }
    }
 <- { "return": {} }
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 5f04dab..92193ab 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2217,13 +2217,8 @@
 # block devices, independent of the block driver:
 #
 # @driver:        block driver name
-# @id:            #optional id by which the new block device can be referred to.
-#                 This option is only allowed on the top level of blockdev-add.
-#                 A BlockBackend will be created by blockdev-add if and only if
-#                 this option is given.
-# @node-name:     #optional the name of a block driver state node (Since 2.0).
-#                 This option is required on the top level of blockdev-add if
-#                 the @id option is not given there.
+# @node-name:     #optional the node name of the new node (Since 2.0).
+#                 This option is required on the top level of blockdev-add.
 # @discard:       #optional discard-related options (default: ignore)
 # @cache:         #optional cache-related options
 # @aio:           #optional AIO backend (default: threads)
@@ -2238,8 +2233,6 @@
 ##
 { 'union': 'BlockdevOptions',
   'base': { 'driver': 'BlockdevDriver',
-# TODO 'id' is a BB-level option, remove it
-            '*id': 'str',
             '*node-name': 'str',
             '*discard': 'BlockdevDiscardOptions',
             '*cache': 'BlockdevCacheOptions',
@@ -2323,29 +2316,18 @@
 # @x-blockdev-del:
 #
 # Deletes a block device that has been added using blockdev-add.
-# The selected device can be either a block backend or a graph node.
-#
-# In the former case the backend will be destroyed, along with its
-# inserted medium if there's any. The command will fail if the backend
-# or its medium are in use.
-#
-# In the latter case the node will be destroyed. The command will fail
-# if the node is attached to a block backend or is otherwise being
-# used.
-#
-# One of @id or @node-name must be specified, but not both.
+# The command will fail if the node is attached to a device or is
+# otherwise being used.
 #
 # This command is still a work in progress and is considered
 # experimental. Stay away from it unless you want to help with its
 # development.
 #
-# @id: #optional Name of the block backend device to delete.
-#
-# @node-name: #optional Name of the graph node to delete.
+# @node-name: Name of the graph node to delete.
 #
 # Since: 2.5
 ##
-{ 'command': 'x-blockdev-del', 'data': { '*id': 'str', '*node-name': 'str' } }
+{ 'command': 'x-blockdev-del', 'data': { 'node-name': 'str' } }
 
 ##
 # @blockdev-open-tray:
-- 
1.8.3.1