Re: [PATCH] btrfs-progs: alias btrfs device delete to btrfs device remove

[David Sterba <dsterba@suse.cz>]

On Thu, Jun 18, 2015 at 03:07:09PM -0700, Omar Sandoval wrote:
> @@ -586,12 +606,13 @@ out:
>  const struct cmd_group device_cmd_group = {
>  	device_cmd_group_usage, NULL, {
>  		{ "add", cmd_add_dev, cmd_add_dev_usage, NULL, 0 },
> -		{ "delete", cmd_rm_dev, cmd_rm_dev_usage, NULL, 0 },
> +		{ "remove", cmd_rm_dev, cmd_rm_dev_usage, NULL, 0 },
>  		{ "scan", cmd_scan_dev, cmd_scan_dev_usage, NULL, 0 },
>  		{ "ready", cmd_ready_dev, cmd_ready_dev_usage, NULL, 0 },
>  		{ "stats", cmd_dev_stats, cmd_dev_stats_usage, NULL, 0 },
>  		{ "usage", cmd_device_usage,
>  			cmd_device_usage_usage, NULL, 0 },
> +		{ "delete", cmd_del_dev, cmd_del_dev_usage, NULL, 0 },

No need to introduce the wrappers, it's enough to add an alternative
usage string and the callback function will be the same. Also please
keep the aliased entries next to each other.

Suggestion for separate change: redefine the last argument (currently to
denote hidden commands) to be a flag set and add a new one for aliases.
That way we can automatically generate a compact help. Currently, the
device section looks like this:

    btrfs device add [options] <device> [<device>...] <path>
        Add a device to a filesystem
    btrfs device remove <device> [<device>...] <path>
        Remove a device from a filesystem
    btrfs device scan [(-d|--all-devices)|<device> [<device>...]]
        Scan devices for a btrfs filesystem
    btrfs device ready <device>
        Check device to see if it has all of its devices in cache for mounting
    btrfs device stats [-z] <path>|<device>
        Show current device IO stats. -z to reset stats afterwards.
    btrfs device usage [options] <path> [<path>..]
        Show detailed information about internal allocations in devices.
    btrfs device delete <device> [<device>...] <path>
        Remove a device from a filesystem (alias of remove)

For the first version it could be simply the first line of the usage string:

    btrfs device add [options] <device> [<device>...] <path>
        Add a device to a filesystem
    btrfs device delete <device> [<device>...] <path>
    btrfs device remove <device> [<device>...] <path>
        Remove a device from a filesystem
    btrfs device scan [(-d|--all-devices)|<device> [<device>...]]
        Scan devices for a btrfs filesystem
    btrfs device ready <device>
        Check device to see if it has all of its devices in cache for mounting
    btrfs device stats [-z] <path>|<device>
        Show current device IO stats. -z to reset stats afterwards.
    btrfs device usage [options] <path> [<path>..]
        Show detailed information about internal allocations in devices.
        Remove a device from a filesystem (alias of remove)