- if qgroup usage is requested, need to check if it is already enabled
if not, turn on this filesystem option an rescan for the given
subvolume
- even rescanning and calculation the qgroup values might be faster
for large subvolumes, than using plain 'du'
- just enable the qgroup usage for dsnap-sync runs. Upstream
still encounters performance hits for regular production
usage (v4.7: consult the wiki)
this is controlled via enabling the global 'btrfs_quota_tmp' flag
Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>
Ralf Zerres
5c596500e1