Re: [Qemu-devel] [PATCH] Add backing file option to qemu-img create help.

[Kevin Wolf <kwolf@redhat.com>]

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Am 12.05.2014 um 19:02 hat Eric Blake geschrieben:
> On 05/12/2014 10:36 AM, Kevin Wolf wrote:
> 
> >>> rebase [-q] [-f fmt] [-t cache] [-p] [-u] -b backing_file [-F
> >>> backing_fmt] filename
> >>
> >> 'rebase' lacks -o; so it must continue to document -b.  This thread was
> >> started in context to the 'create' subcommand, not the 'rebase'
> >> subcommand.  (Arguably, we may need to add -o to rebase someday, but
> >> that's not for this patch)
> > 
> > What would qemu-img rebase do with -o? It is just for (safely) changing
> > the backing file, not for updating options. There is qemu-img amend for
> > that, and it does have an -o option.
> 
> It's a consistency argument.  Why can't we have:
> 
> rebase -o backing_file=file,backing_fmt=fmt
> 
> similar to create, instead of having to treat rebase as the oddball
> command that still takes separate options for two highly related items?

But that's inconsistent with other -o options if you can't say:

    rebase -o lazy_refcounts=on

rebase will always be the oddball because a backing file is not just an
option for it, but it is the whole purpose of the command. Perhaps we
shouldn't have used -b, but just a second non-option argument. But I
don't think changing this now is worth it.

Kevin

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