[PATCH 0/1][SRU][Disco] shiftfs: allow changing ro/rw for

[Christian Brauner]

https://bugs.launchpad.net/bugs/1832316

SRU Justification

Impact: Stéphane reported regression for btrfs workloads employing shiftfs.
Unprivileged users can already toggle whether a subvolume will be ro or
rw. This is broken on current shiftfs as we haven't whitelisted these
ioctls().

Fix: To enable this with shiftfs we need to whitelist BTRFS_IOC_FS_INFO,
BTRFS_IOC_SUBVOL_GETFLAGS, BTRFS_IOC_SUBVOL_SETFLAGS. All of them should
be safe for unprivileged users.

Regression Potential: Limited to shiftfs.

Test Case: Tested with LXD running shiftfs on top of btrfs and verified
btrfs subvolumes can be made ro or rw.

Thanks,
Christian

Christian Brauner (1):
  UBUNTU: SAUCE: shiftfs: allow changing ro/rw for subvolumes

 fs/shiftfs.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

-- 
2.21.0