[PATCH v3 0/2] New qgroup creation / removal ioctl

[Sargun Dhillon <sargun@sargun.me>]

This patch introduces two new ioctls for creating, and removing qgroups.
These ioctls have a new args structure that allows passing flags, and
some reserved fields for future expansion. The ioctls prevent some
operations around level-0 qgroups as well.


The create operation prevents the creation of level-0 qgroups for
subvolumes that do not exist. The delete operations prevents the
deletion of level-0 qgroups that reference active volumes.

There are two different ioctl for creation, and deletion to enable
filtering of the ioctls via tools like seccomp-bpf. Currently, there
is one "swiss-army" ioctl that's multiplexed for creation, and
deletion, and you need to be able to dereference user memory to determine
whether or not it's a destructive operation -- something that cannot
be done via seccomp nor LSMs.

Changes since v2:
  * Use a common datastructure for removal and creation
  * Remove deprecation message for old API
Changes since v1:
  * Remove creation of level-0 qgroups without subvol


Sargun Dhillon (2):
  btrfs: Fail on removing qgroup if del_qgroup_item fails
  btrfs: Add new ioctl uapis for qgroup creation / removal

 fs/btrfs/ioctl.c           | 100 ++++++++++++++++++++++++++++++++++++++++++++-
 fs/btrfs/qgroup.c          |  79 ++++++++++++++++++++++++++++++++---
 fs/btrfs/qgroup.h          |   6 ++-
 include/uapi/linux/btrfs.h |  16 ++++++++
 4 files changed, 192 insertions(+), 9 deletions(-)

-- 
2.9.3