Am 26.09.2012 16:25, schrieb Jeff Cody: > On 09/26/2012 10:13 AM, Kevin Wolf wrote: >> Am 25.09.2012 18:29, schrieb Jeff Cody: >>> The command for live block commit is added, which has the following >>> arguments: >>> >>> device: the block device to perform the commit on (mandatory) >>> base: the base image to commit into; optional (if not specified, >>> it is the underlying original image) >>> top: the top image of the commit - all data from inside top down >>> to base will be committed into base. optional (if not specified, >>> it is one below the active image) - see note below >>> speed: maximum speed, in bytes/sec >>> >>> note: eventually this will support merging down the active layer, >>> but that code is not yet complete. If the active layer is passed >>> in currently as top, or top is left to the default, then an error >>> will be returned. >>> >>> The is done as a block job, so upon completion a BLOCK_JOB_COMPLETED will >>> be emitted. >>> >>> Signed-off-by: Jeff Cody <jc...@redhat.com> >> >>> diff --git a/qapi-schema.json b/qapi-schema.json >>> index 14e4419..e614453 100644 >>> --- a/qapi-schema.json >>> +++ b/qapi-schema.json >>> @@ -1468,6 +1468,41 @@ >>> 'returns': 'str' } >>> >>> ## >>> +# @block-commit >>> +# >>> +# Live commit of data from overlay image nodes into backing nodes - i.e., >>> +# writes data between 'top' and 'base' into 'base'. >>> +# >>> +# @device: the name of the device >>> +# >>> +# @base: #optional The file name of the backing image to write data into. >>> +# If not specified, this is the deepest backing image >>> +# >>> +# @top: #optional The file name of the backing image within the image >>> chain, >>> +# which contains the topmost data to be committed down. >>> +# If not specified, this is one layer below the active >>> +# layer (i.e. active->backing_hd). >> >> Why isn't active the default any more? I know, we don't support it yet, >> but long term this is what makes most sense as a default. >> > > Eric had a similar question, and asked if anyone had any preference - > this was my response: > > --- > > I guess I don't have a strong preference either - I originally had it > the other way, but then that meant the default in the current > implementation was actually an error.
We can make it non-optional for now and use active as the default once we introduce support for committing the active layer. > Also, I assumed (danger!) that the most common use of commit would be a > snapshot, followed by a commit of active->backing_hd. With that > assumption, it seemed like a sane default. > > --- > > I can certainly revert back to having the active layer be the top, if > that is the preference. I think it is, if nothing else for consistency with the existing synchronous 'commit' command. Kevin
