[Samba] SMB2 leases slowing down shared access to files

[Fabian Fritz]

Hi,

we recently updated to Samba 4.9.2 (running on a Solaris 10 server).
All our client machines are Windows 7 PCs. Since then however, we
noticed that if one client opens an executable from a share and
somebody else tries to copy that folder to their local PC, it takes an
incredibly long time; Sometimes it doesn't work at all.
Also, if somebody has an .xlsx-File open, other people have to wait
for a long time as well or cannot open that file at all. Before the
update, users just got a notification that somebody else had opened
the spreadsheet and they could just choose to open it read-only and
that worked fine.

Investigating this, I first tried putting ".exe" in the "veto oplock
files" list. After I also put dlls and everything the program accessed
in there as well, I could copy the folder from a share much faster, as
before. As this doesn't take care of the problems with Office
documents, I tried setting "smb2 leases = no" instead. Immediately
everything started working fast again. It also brought back the dialog
window in Office, asking you if you want to have read-only access. It
seems like files that have "LEASE(LWH)" as the lock type in smbstatus
have this problem.

I was surprised that smb2 leases seem to slow everything down, as the
documentation suggests that you can expect a speedup from this. There
were no obvious errors in the log file.

Thanks,
Fabian