Comment 19 for bug 1748689

I can also confirm on Xenial running 4.15.0-13:
user@host:~$ dmesg | tail
[ 1331.150999] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1331.197478] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1331.245486] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1631.292647] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1631.335005] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1631.374513] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1931.420138] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1931.467038] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5
[ 1931.506586] CIFS VFS: ioctl error in smb2_get_dfs_refer rc=-5

user@host:~$ uname -a
Linux host 4.15.0-13-generic #14~16.04.1-Ubuntu SMP Sat Mar 17 03:04:59 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

user@host:~$ mount -l | grep cifs
//server/share1 on /var/repositories.asp/staging/share1 type cifs (rw,relatime,vers=3.02,cache=strict,username=***,domain=***,uid=59948,forceuid,gid=33,forcegid,addr=1.1.1.1,file_mode=0664,dir_mode=0775,nocase,soft,nounix,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1,_netdev)
//server/share2 on /var/repositories.asp/staging/share2 type cifs (rw,relatime,vers=3.02,cache=strict,username=***,domain=***,uid=59948,forceuid,gid=33,forcegid,addr=1.1.1.1,file_mode=0664,dir_mode=0775,nocase,soft,nounix,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1,_netdev)
//server/share3 on /var/repositories.asp/staging/share3 type cifs (rw,relatime,vers=3.02,cache=strict,username=***,domain=***,uid=59948,forceuid,gid=33,forcegid,addr=1.1.1.1,file_mode=0664,dir_mode=0775,nocase,soft,nounix,mapposix,rsize=1048576,wsize=1048576,echo_interval=60,actimeo=1,_netdev)

names, usernames, domains redacted for privacy.