Btrfs-progs: introduce -g -c --sort options into btrfs subvol list command

This patch introduces '-g' '-c' '--sort' options

The option '-g' can help you filter the subvolumes by the generation, you may
use it just like:

	btrfs subvol list -g +/-value <path>

'+' means the generation of the subvolumes should >= the value you specified.
'-' means the generation should <= the value
If you don't input either '+' nor '-', this command will list the subvolumes
that their generation equals to the value.

However if you want to find gengeration between value1 and value2
you may use the above like:

        btrfs sub list -g -value1 -g +value2 <path>

The option '-c' can help you filter the subvolumes by the ogeneration, you may
use it just like:

	btrfs subvol list -c +/-value <path>

The usage is the same to '-g'

You might want to list subvolumes in order of some items, such as root id, gen
and so on, you can use '--sort'. Now you can sort the subvolumes by root id,
gen, ogen and path.

For example:
If you want to list subvolumes in order of rootid, you can use the option like
that:

	btrfs sub list --sort=+/-rooid <path>

Here, '+' means the result is sorted by ascending order. '-' is by descending
order. If you don't specify either '+' nor '-', the result is sorted by
default - ascending order.

If you want to combine sort items, you do it like that:

	btrfs sub list --sort=-rootid,+path,ogen,gen <path>

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>

0 files changed, 0 insertions, 0 deletions