linux-mainline/include
Daniel Xu 0c47383ba3 kernfs: Add option to enable user xattrs
User extended attributes are useful as metadata storage for kernfs
consumers like cgroups. Especially in the case of cgroups, it is useful
to have a central metadata store that multiple processes/services can
use to coordinate actions.

A concrete example is for userspace out of memory killers. We want to
let delegated cgroup subtree owners (running as non-root) to be able to
say "please avoid killing this cgroup". This is especially important for
desktop linux as delegated subtrees owners are less likely to run as
root.

This patch introduces a new flag, KERNFS_ROOT_SUPPORT_USER_XATTR, that
lets kernfs consumers enable user xattr support. An initial limit of 128
entries or 128KB -- whichever is hit first -- is placed per cgroup
because xattrs come from kernel memory and we don't want to let
unprivileged users accidentally eat up too much kernel memory.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-03-16 15:53:47 -04:00
..
acpi
asm-generic
clocksource
crypto
drm
dt-bindings ARM: SoC: late updates 2020-02-08 14:17:27 -08:00
keys
kunit
kvm
linux kernfs: Add option to enable user xattrs 2020-03-16 15:53:47 -04:00
math-emu
media
misc
net
pcmcia
ras
rdma
scsi
soc ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
sound ARM: Device-tree updates 2020-02-08 13:58:44 -08:00
target
trace ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
uapi clone3: allow spawning processes into cgroups 2020-02-12 17:57:51 -05:00
vdso
video
xen