qapi: introduce PreallocMode and new PreallocModes full and falloc.
This patch prepares for the subsequent patches.
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 4064d5b..95dcd81 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1708,3 +1708,20 @@
'len' : 'int',
'offset': 'int',
'speed' : 'int' } }
+
+# @PreallocMode
+#
+# Preallocation mode of QEMU image file
+#
+# @off: no preallocation
+# @metadata: preallocate only for metadata
+# @falloc: like @full preallocation but allocate disk space by
+# posix_fallocate() rather than writing zeros.
+# @full: preallocate all data by writing zeros to device to ensure disk
+# space is really available. @full preallocation also sets up
+# metadata correctly.
+#
+# Since 2.2
+##
+{ 'enum': 'PreallocMode',
+ 'data': [ 'off', 'metadata', 'falloc', 'full' ] }
