commit: Allow users to request only format driver names in backing file format
Introduce a new flag 'backing-mask-protocol' for the block-commit QMP
command which instructs the internals to use 'raw' instead of the
protocol driver in case when a image is used without a dummy 'raw'
wrapper.
The flag is designed such that it can be always asserted by management
tools even when there isn't any update to backing files.
The flag will be used by libvirt so that the backing images still
reference the proper format even when libvirt will stop using the dummy
raw driver (raw driver with no other config). Libvirt needs this so that
the images stay compatible with older libvirt versions which didn't
expect that a protocol driver name can appear in the backing file format
field.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <2cb46e37093ce793ea1604abc8bbb90f4c8e434b.1701796348.git.pkrempa@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qapi/block-core.json b/qapi/block-core.json
index ca390c5..726145e 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1810,6 +1810,11 @@
# Care should be taken when specifying the string, to specify a
# valid filename or protocol. (Since 2.1)
#
+# @backing-mask-protocol: If true, replace any protocol mentioned in the
+# 'backing file format' with 'raw', rather than storing the protocol
+# name as the backing format. Can be used even when no image header
+# will be updated (default false; since 9.0).
+#
# @speed: the maximum speed, in bytes per second
#
# @on-error: the action to take on an error. 'ignore' means that the
@@ -1856,7 +1861,8 @@
'*base': { 'type': 'str', 'features': [ 'deprecated' ] },
'*top-node': 'str',
'*top': { 'type': 'str', 'features': [ 'deprecated' ] },
- '*backing-file': 'str', '*speed': 'int',
+ '*backing-file': 'str', '*backing-mask-protocol': 'bool',
+ '*speed': 'int',
'*on-error': 'BlockdevOnError',
'*filter-node-name': 'str',
'*auto-finalize': 'bool', '*auto-dismiss': 'bool' },
