Comment 20 for bug 1748689

Also confirmed on 4.15.0-22:

user@host:~$ uname -a
Linux host 4.15.0-22-generic #24~16.04.1-Ubuntu SMP Fri May 18 09:46:31 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
user@host:~$ dmesg | tail
[ 9.579718] new mount options do not match the existing superblock, will be ignored
[ 9.781330] new mount options do not match the existing superblock, will be ignored
[ 9.957734] TCP: eth0: Driver has suspect GRO implementation, TCP performance may be compromised.
[ 10.468800] FS-Cache: Loaded
[ 10.528082] FS-Cache: Netfs 'cifs' registered for caching
[ 10.528179] Key type cifs.spnego registered
[ 10.528182] Key type cifs.idmap registered
[ 10.910445] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 10.911089] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 10.911723] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5