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>
This commit is contained in:
Peter Krempa 2023-12-05 18:14:41 +01:00 committed by Kevin Wolf
parent 014b99a8e4
commit 4b028cbe75
8 changed files with 58 additions and 12 deletions

View file

@ -82,6 +82,8 @@ void stream_start(const char *job_id, BlockDriverState *bs,
* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
* @on_error: The action to take upon error.
* @backing_file_str: String to use as the backing file in @top's overlay
* @backing_mask_protocol: Replace potential protocol name with 'raw' in
* 'backing file format' header
* @filter_node_name: The node name that should be assigned to the filter
* driver that the commit job inserts into the graph above @top. NULL means
* that a node name should be autogenerated.
@ -92,6 +94,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *base, BlockDriverState *top,
int creation_flags, int64_t speed,
BlockdevOnError on_error, const char *backing_file_str,
bool backing_mask_protocol,
const char *filter_node_name, Error **errp);
/**
* commit_active_start: