[PATCH v2 4/4] qapi: add blockdev-replace command
Add a command that can replace bs in following BdrvChild structures:
- qdev blk root child
- block-export blk root child
- any child BlockDriverState selected by child-name
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)virtuozzo.com>
---
qapi/block.json | 61 +++++++++++++++++++++++++++++++++++++++++++++
block/qapi-sysemu.c | 56 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 117 insertions(+)
diff --git a/qapi/block.json b/qapi/block.json
index 82fcf2c914..a4dd1e34d4 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -570,3 +570,64 @@
'*boundaries-read': ['uint64'],
'*boundaries-write': ['uint64'],
'*boundaries-flush': ['uint64'] } }
+##
+# @BlockParentType:
+#
+# Since 7.0
+##
+{ 'enum': 'BlockParentType',
+ 'data': ['qdev', 'driver', 'export'] }
+
+##
+# @BdrvChildRefQdev:
+#
+# Since 7.0
+##
+{ 'struct': 'BdrvChildRefQdev',
+ 'data': { 'qdev-id': 'str' } }
+
+##
+# @BdrvChildRefExport:
+#
+# Since 7.0
+##
+{ 'struct': 'BdrvChildRefExport',
+ 'data': { 'export-id': 'str' } }
+
+##
+# @BdrvChildRefDriver:
+#
+# Since 7.0
+##
+{ 'struct': 'BdrvChildRefDriver',
+ 'data': { 'node-name': 'str', 'child': 'str' }
}
+
+##
+# @BlockdevReplace:
+#
+# Since 7.0
+##
+{ 'union': 'BlockdevReplace',
+ 'base': {
+ 'parent-type': 'BlockParentType',
+ 'new-child': 'str'
+ },
+ 'discriminator': 'parent-type',
+ 'data': {
+ 'qdev': 'BdrvChildRefQdev',
+ 'export': 'BdrvChildRefExport',
+ 'driver': 'BdrvChildRefDriver'
+ } }
+
+##
+# @x-blockdev-replace:
+#
+# Replace a block-node associated with device (selected by
+# @qdev-id) or with block-export (selected by @export-id) or
+# any child of block-node (selected by @node-name and @child)
+# with @new-child block-node.
+#
+# Since 7.0
+##
+{ 'command': 'x-blockdev-replace', 'boxed': true,
+ 'data': 'BlockdevReplace' }
diff --git a/block/qapi-sysemu.c b/block/qapi-sysemu.c
index 8498402ad4..ca1aaef376 100644
--- a/block/qapi-sysemu.c
+++ b/block/qapi-sysemu.c
@@ -588,3 +588,59 @@ void qmp_block_latency_histogram_set(
}
}
}
+
+void qmp_x_blockdev_replace(BlockdevReplace *repl, Error **errp)
+{
+ BdrvChild *child = NULL;
+ BlockDriverState *new_child_bs;
+
+ if (repl->parent_type == BLOCK_PARENT_TYPE_DRIVER) {
+ BlockDriverState *parent_bs;
+
+ parent_bs = bdrv_find_node(repl->u.driver.node_name);
+ if (!parent_bs) {
+ error_setg(errp, "Block driver node with node-name '%s' not
"
+ "found", repl->u.driver.node_name);
+ return;
+ }
+
+ child = bdrv_find_child(parent_bs, repl->u.driver.child);
+ if (!child) {
+ error_setg(errp, "Block driver node '%s' doesn't have child
"
+ "named '%s'", repl->u.driver.node_name,
+ repl->u.driver.child);
+ return;
+ }
+ } else {
+ /* Other types are similar, they work through blk */
+ BlockBackend *blk;
+ bool is_qdev = repl->parent_type == BLOCK_PARENT_TYPE_QDEV;
+ const char *id =
+ is_qdev ? repl->u.qdev.qdev_id : repl->u.export.export_id;
+
+ assert(is_qdev || repl->parent_type == BLOCK_PARENT_TYPE_EXPORT);
+
+ blk = is_qdev ? blk_by_qdev_id(id, errp) : blk_by_export_id(id, errp);
+ if (!blk) {
+ return;
+ }
+
+ child = blk_root(blk);
+ if (!child) {
+ error_setg(errp, "%s '%s' is empty, nothing to replace",
+ is_qdev ? "Device" : "Export", id);
+ return;
+ }
+ }
+
+ assert(child);
+ assert(child->bs);
+
+ new_child_bs = bdrv_find_node(repl->new_child);
+ if (!new_child_bs) {
+ error_setg(errp, "Node '%s' not found", repl->new_child);
+ return;
+ }
+
+ bdrv_replace_child_bs(child, new_child_bs, errp);
+}
--
2.31.1