On Sat, Feb 04, 2012 at 02:06:28PM +0100, Goffredo Baroncelli wrote:
> Hi Ilya,
>
> On Friday, 03 February, 2012 22:49:09 Ilya Dryomov wrote:
> > Hello,
> >
> > This is the userspace part of restriper, rebased onto the new progs
> > infrastructure. Restriper commands are located under 'balance' prefix,
> > which is now the top level command group. However to not confuse
> > existing users 'balance' prefix is also available under 'filesystem':
> >
> > btrfs [filesystem] balance start
> > btrfs [filesystem] balance pause
> > btrfs [filesystem] balance cancel
> > btrfs [filesystem] balance resume
> > btrfs [filesystem] balance status
> >
> > Backwards compatibility is fully preserved thanks to the new command
> > parser: the old 'btrfs filesystem balance <path>' works as expected.
>
> I prefer to avoid prefix which may confuse the user. If I have a subvolume
> called "s", what means:
>
> btrfs filesystem balance s
>
> Is it a missing argument (the path required for btrfs filesystem balance) or
> is it a synonymus of
>
> btrfs filesystem balance start ./s
>
> (or btrfs filesystem balance stop ./s)
>
> ?
It's a path. It's unambiguous because every subcommand requires an argument.
If you omit the path argument you get the following:
btrfs-progs-new$ ./btrfs fi balance
usage: btrfs [filesystem] balance [<command>] [options] <path>
btrfs [filesystem] balance start [options] <path>
Balance chunks across the devices
btrfs [filesystem] balance pause <path>
Pause running balance
btrfs [filesystem] balance cancel <path>
Cancel running or paused balance
btrfs [filesystem] balance resume <path>
Resume interrupted balance
btrfs [filesystem] balance status [-v] <path>
Show status of running or paused balance
'btrfs filesystem balance' command is deprecated, please use
'btrfs balance start' command instead.
which clearly indicates that <command> is optional. Finally, if you type
btrfs fi balance s /mnt
(which is ambiguous because 's' could mean 'start' or 'status') you get
the following:
btrfs-progs-new$ ./btrfs fi balance s /mnt
btrfs filesystem balance: ambiguous token 's'
Did you mean one of these ?
start
status
Pretty clear to me.
>
> To me I prefer to add another family of command called
>
> btrfs balance *
>
> and to leave
>
> btrfs filesystem balance
>
> as synonymus of
>
> btrfs balance start
I discussed this with Chris and we agreed that it will be confusing if
'btrfs filesystem balance' is different from 'btrfs balance'.
>
>
> This was discussed several years ago. Allowing the user to abbreviate the
> commands fights with the ability to have different length of commands , when
> an option could beconfused with a command (s vs start/stop....).
It generally does, but in this particular case (where every subcommand
in the group requires at least one argument) it does not.
Thanks,
Ilya
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