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-rw-r--r--qapi/block-core.json25
1 files changed, 23 insertions, 2 deletions
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 06674c25c9..c8ce1d9d5d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2825,13 +2825,14 @@
 # @blklogwrites: Since 3.0
 # @blkreplay: Since 4.2
 # @compress: Since 5.0
+# @copy-before-write: Since 6.2
 #
 # Since: 2.9
 ##
 { 'enum': 'BlockdevDriver',
   'data': [ 'blkdebug', 'blklogwrites', 'blkreplay', 'blkverify', 'bochs',
-            'cloop', 'compress', 'copy-on-read', 'dmg', 'file', 'ftp', 'ftps',
-            'gluster',
+            'cloop', 'compress', 'copy-before-write', 'copy-on-read', 'dmg',
+            'file', 'ftp', 'ftps', 'gluster',
             {'name': 'host_cdrom', 'if': 'HAVE_HOST_BLOCK_DEVICE' },
             {'name': 'host_device', 'if': 'HAVE_HOST_BLOCK_DEVICE' },
             'http', 'https', 'iscsi',
@@ -4050,6 +4051,25 @@
   'data': { '*bottom': 'str' } }
 
 ##
+# @BlockdevOptionsCbw:
+#
+# Driver specific block device options for the copy-before-write driver,
+# which does so called copy-before-write operations: when data is
+# written to the filter, the filter first reads corresponding blocks
+# from its file child and copies them to @target child. After successfully
+# copying, the write request is propagated to file child. If copying
+# fails, the original write request is failed too and no data is written
+# to file child.
+#
+# @target: The target for copy-before-write operations.
+#
+# Since: 6.2
+##
+{ 'struct': 'BlockdevOptionsCbw',
+  'base': 'BlockdevOptionsGenericFormat',
+  'data': { 'target': 'BlockdevRef' } }
+
+##
 # @BlockdevOptions:
 #
 # Options for creating a block device.  Many options are available for all
@@ -4101,6 +4121,7 @@
       'bochs':      'BlockdevOptionsGenericFormat',
       'cloop':      'BlockdevOptionsGenericFormat',
       'compress':   'BlockdevOptionsGenericFormat',
+      'copy-before-write':'BlockdevOptionsCbw',
       'copy-on-read':'BlockdevOptionsCor',
       'dmg':        'BlockdevOptionsGenericFormat',
       'file':       'BlockdevOptionsFile',