[Samba] Errors for shares since 4.12.0

[Andreas Hauffe]

Hi,

I tried samba 4.12.0 on our file server which is a domain member and 
exporting some shares. We're getting some strange errors on some shares 
since the update.

Right after starting or restarting smbd everything is fine. After short 
while (seconds or a few minutes) users are getting errors when trying to 
access the shares, e.q. "Invalid Handle Error", "An unexpected network 
error occurred", "The process cannot access the file because it is being 
used by another process", ... (these are translations of the error 
messages from german, so the original english message can be slightly 
different).

Sometimes the shares are reachable for users after waiting a while but 
sometimes not.

smb.conf:

# Global parameters
[global]
         bind interfaces only = Yes
         dedicated keytab file = /etc/krb5.keytab
         interfaces = lo enp1s0f0
         kerberos method = secrets and keytab
         realm = SUBDOM.DOM.EXAMPLE.COM
         security = ADS
         server min protocol = SMB3_00
         template homedir = /home/users/linux/%U
         template shell = /bin/bash
         winbind refresh tickets = Yes
         winbind separator = +
         workgroup = ILRW
         idmap config dom : range = 10000-9999999
         idmap config dom : backend = rid
         idmap config subdom : range = 3000-9999
         idmap config subdom : backend = rid
         idmap config * : range = 2000-2999
         idmap config * : backend = tdb
         map acl inherit = Yes
         vfs objects = acl_xattr

[share1]
         comment = Share 1
         create mask = 0740
         directory mask = 0750
         force create mode = 0660
         force directory mode = 0660
         force group = "SUBDOM+worker"
         inherit permissions = Yes
         path = PATHNAME
         read only = No
         root preexec = /bin/MK_PAPIERKORB %H "%u" %h %S
         smb encrypt = desired
         valid users = +SUBDOM+worker
         vfs objects = recycle crossrename
         recycle:exclude_dir = tmp | temp | cache
         recycle:exclude = *.TMP | *.tmp | ~$*.doc
         recycle:noversions = *.ini | *.dat
         recycle:versions = Yes
         recycle:maxsize = 536870912
         recycle:touch = Yes
         recycle:keeptree = Yes
         recycle:directory_mode = 0700
         recycle:repository = %H/.Papierkorb/%S

[share2]
         comment = Share 2
         inherit acls = Yes
         path = PATHNAME
         read only = No
         smb encrypt = desired
         valid users = +SUBDOM+worker +SUBDOM+user
         acl_xattr:ignore system acls = yes

[share3]
         comment = Share 3
         create mask = 0660
         directory mask = 0770
         force create mode = 0660
         force directory mode = 0770
         force group = "SUBDOM+group2"
         path = PATHNAME
         read only = No
         root preexec = /bin/MK_PAPIERKORB %H "%u" %h %S
         smb encrypt = desired
         valid users = +SUBDOM+group2
         vfs objects = recycle crossrename
         recycle:exclude_dir = tmp | temp | cache
         recycle:exclude = *.TMP | *.tmp | ~$*.doc
         recycle:noversions = *.ini | *.dat
         recycle:versions = Yes
         recycle:maxsize = 536870912
         recycle:touch = Yes
         recycle:keeptree = Yes
         recycle:directory_mode = 0700
         recycle:repository = %H/.Papierkorb/%S

[share4]
         comment = Share 4
         path = PATHNAME
         smb encrypt = desired
         valid users = +SUBDOM+group2 +SUBDOM+group3 +SUBDOM+group4

Regards,
Andreas