Is there a convenient way to get information on all btrfs filesystems subvolumes without resorting to C, i.e. in POSIX shell ? /sys/fs/btrfs contains info only on filesystems, nothing on subvolumes, so currently i end up mounting all filesystems in a temp folder,  scanning them with btrfs subvol list, then parsing the resulting output.Needless to say, that is fairly ugly.This is with a 3.16.x kernel and btrfs-progs v3.14.1 (from stock ubuntu 14.10).Edit: below is the (ugly) script i'm currently using. I know i could get the info i need using pure C, and that's probably what i'll end up doing, but i was wondering if there was a simpler, more elegant way.#!/bin/bashfor i in /sys/fs/btrfs/*[!features]; do   device=/dev/$(basename $i/devices/*)  mountpoint=/var/lib/btrfs/tmp/mnt/$(basename $i)  [ -d $mountpoint ] || mkdir $mountpoint  grep -qs $mountpoint /proc/mounts  [ $? -ne 0 ] && mount -v $device $mountpoint  while read -r subvol; do    # whatever you want  done < <(btrfs subvolume list $mountpoint)  umount $mountpoint  rmdir $mountpointdone
List all btrfs filesystems and subvolumes in shell
shell;btrfs