btrfs: ensure that metadata and flush are issued from the root cgroup
Issuing metdata or otherwise shared IOs from !root cgroup can lead to
priority inversion. This patch ensures that those IOs are always
issued from the root cgroup.
This patch updates btrfs_update_iflags() to not set S_CGROUPWB on
btree_inodes. This isn't strictly necessary as those inodes don't
call the function during init; however, this serves as documentation
and prevents possible future mistakes. If this isn't desirable,
please feel free to drop the section.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
3 files changed
