diff options
| author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2021-11-04 09:58:11 +0100 |
|---|---|---|
| committer | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2021-11-09 18:21:19 +0100 |
| commit | 1084159b31015e003946d199cbfecaec282e0eb2 (patch) | |
| tree | 68bd5ae9d818e303ef85d7c06af2296d824633f3 /qapi/block-core.json | |
| parent | 24d6cc1fa17745228694a3b2c94e8a5cbd4fc4d9 (diff) | |
qapi: deprecate drive-backup
Modern way is using blockdev-add + blockdev-backup, which provides a
lot more control on how target is opened.
As example of drive-backup problems consider the following:
User of drive-backup expects that target will be opened in the same
cache and aio mode as source. Corresponding logic is in
drive_backup_prepare(), where we take bs->open_flags of source.
It works rather bad if source was added by blockdev-add. Assume source
is qcow2 image. On blockdev-add we should specify aio and cache options
for file child of qcow2 node. What happens next:
drive_backup_prepare() looks at bs->open_flags of qcow2 source node.
But there no BDRV_O_NOCAHE neither BDRV_O_NATIVE_AIO: BDRV_O_NOCAHE is
places in bs->file->bs->open_flags, and BDRV_O_NATIVE_AIO is nowhere,
as file-posix parse options and simply set s->use_linux_aio.
The documentation is updated in a minimal way, so that drive-backup is
noted only as a deprecated command, and blockdev-backup used in most of
places.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'qapi/block-core.json')
| -rw-r--r-- | qapi/block-core.json | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/qapi/block-core.json b/qapi/block-core.json index 33e8507d10..1d3dd9cb48 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1709,6 +1709,9 @@ # The operation can be stopped before it has completed using the # block-job-cancel command. # +# Features: +# @deprecated: This command is deprecated. Use @blockdev-backup instead. +# # Returns: - nothing on success # - If @device is not a valid block device, GenericError # @@ -1724,7 +1727,7 @@ # ## { 'command': 'drive-backup', 'boxed': true, - 'data': 'DriveBackup' } + 'data': 'DriveBackup', 'features': ['deprecated'] } ## # @blockdev-backup: |