[Samba] Weird errors for shares since 4.12.0

[Francesco Malvezzi]

Hi all,

I am experiencing something similar to what Andreas described on march 9th.

Since upgrade to samba-4.12.0, users can sometimes have errors on
accessing shares. Errors can be different, most often
NT_STATUS_SHARING_VIOLATION, but also "Invalid handle".

Just restarting smbd fixes the issue, for a while.

The server serves six shares: one or a few may be locked, the other are not.

According to the users, the issue "can fade away" after a while (30-60
minutes), but not all the times.

While Andreas' server was a AD-DC, mine is a ROLE_DOMAIN_MEMBER in a NT
domain.

# Global parameters
[global]
	dns proxy = No
	domain master = No
	load printers = No
	local master = No
	log file = /var/log/samba/log.%m
	max log size = 1000
	name resolve order = wins lmhosts host bcast
	os level = 0
	panic action = /usr/share/samba/panic-action %d
	preferred master = No
	security = DOMAIN
	server string = "dati"
	template homedir = /homel/%U
	template shell = /bin/mosh
	username map = /etc/samba/user.map
	winbind use default domain = Yes
	wins server = 10.0.0.19
	workgroup = EXAMPLE
	idmap config example:unix_nss_info = yes
	idmap config example:range = 1-999999
	idmap config example:backend = nss
	idmap config * : range = 1000000-3000000
	idmap config * : backend = tdb


[share1]
	comment = share1
	force create mode = 0770
	force directory mode = 02770
	force group = +example:domains:share1
	path = /samba_share/share1
	read only = No
	valid users = +example:domains:share1
	veto oplock files = /*.mdb/*.MDB/*.dbf/*.DBF/*.xls/*.XLS/


[share2]
	comment = share2
	force create mode = 0770
	force directory mode = 02770
	force group = +example:domains:share2
	path = /samba_share/share2
	read only = No
	valid users = +example:domains:share2 scannerut
	veto oplock files = /*.mdb/*.MDB/*.dbf/*.DBF/*.xls/*.XLS/

[...]
follow four more shares, but you got the idea.

What should I edit to bring back the smoothless samba-4.11.* user
experience?

Thank you so much,

franz