Hello,

with 5.4.0-rc7 and 4.9.200 we see the following errors with 
mkdir or touch on a ocfs2 mountpoint:

root@s2:/shared/ClusterShareDisk# mkdir dir
mkdir: cannot create directory Ądirą: Invalid argument

which produces this output:

root@s2:/shared/ClusterShareDisk# dmesg
[ 6918.815770] (mkdir,19461,0):ocfs2_xa_set:2242 ERROR: status = -22
[ 6918.815772] (mkdir,19461,0):ocfs2_mknod:408 ERROR: status = -22
[ 6918.816215] (mkdir,19461,0):ocfs2_mknod:486 ERROR: status = -22
[ 6918.816216] (mkdir,19461,0):ocfs2_mkdir:652 ERROR: status = -22

We got some ACLs:
$ getfacl /shared/ClusterShareDisk/
getfacl: Removing leading '/' from absolute path names
# file: shared/ClusterShareDisk/
# owner: root
# group: root
user::rwx
user:admin:rwx
group::rwx
mask::rwx
other::---
default:user::rwx
default:user:admin:rwx
default:group::rwx
default:mask::rwx
default:other::---

And of course it is mounted with user_xattr and acl option.

Reverting
commit 56e94ea132bb5c2c1d0b60a6aeb34dcb7d71a53d
Author: Jia-Ju Bai <baijiaju1990@gmail.com>
Date:   Sun Oct 6 17:57:50 2019 -0700

     fs: ocfs2: fix possible null-pointer dereferences in
ocfs2_xa_prepare_entry()

fixes the problem.

Greetings,


     Thomas