Add the ability to enable simple quotas on an existing file system at
rest with btrfstune.
This is similar to the functionality in mkfs, except it must also find
all the roots for which it must create qgroups. Note that this *does
not* retroactively compute usage for existing extents as that is
impossible for data. This is consistent with the behavior of the live
enable ioctl.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Boris Burkov