[PATCH] flock() files even with a permissive share mode.

[Jeremy Allison]

On Wed, Feb 06, 2019 at 04:15:06PM -0500, J. Bruce Fields via samba-technical wrote:
> On Wed, Feb 06, 2019 at 09:26:09PM +0100, Volker Lendecke wrote:
> > On Wed, Feb 06, 2019 at 03:13:28PM -0500, J. Bruce Fields via samba-technical wrote:
> > > I could help write up or compile some sort of "introduction to NFS
> > > locking for SMB developers".  NFSv4 has byte-range locks, share locks,
> > > and delegations, you're interested in all three?
> > 
> > Very much so. For a start:
> > 
> > brlocks == brlocks (how similar are they to Posix in NFS?)
> 
> Right.  They're the same as posix locks, so the documentation under
> "Advisory record locking" in the fcntl(2) man page should all apply.
> They're fully implemented and commonly used on both the client and
> server side.

Quick comment. SMB2+ (and Samba) implements F_OFD locks
these days which have slightly different semantics to
standard POSIX locks (i.e. locks on a different file
descriptor from the same process can conflict). Does
NFSv4+ make any allowances for OFD locks these days ?