On Fri, 2010-09-10 at 04:44 +0530, Suresh Jayaraman wrote:
> On 09/10/2010 01:50 AM, Jeff Layton wrote:
> > On Fri, 10 Sep 2010 01:06:38 +0530
> > Suresh Jayaraman <sjayaraman@xxxxxxx> wrote:
> >
> >> NFS clients since 2.6.12 support flock locks by emulating fcntl byte-range
> >> locks. Due to this, some windows applications which seem to use both flock
> >> (share mode lock mapped as flock by Samba) and fcntl locks sequentially on
> >> the same file, can't lock as they falsely assume the file is already locked.
> >> The problem was reported on a setup with windows clients accessing excel files
> >> on a Samba exported share which is originally a NFS mount from a NetApp filer.
> >>
> >> Older NFS clients (< 2.6.12) did not see this problem as flock locks were
> >> considered local. To support legacy flock behavior, this patch adds a mount
> >> option "-olocal_lock=" which can take the following values:
> >>
> >> 'none' - Neither flock locks or fcntl/posix locks are local
> >> 'flock'/'posix' - flock locks are local
> > ^^^^^^^
> > "posix" ought to be synonymous with "fcntl". "flock" was a BSD-ism.
>
> Oops, that should have read 'fcntl/posix' (though the code gets it right)..
Yup. It appears to be a changelog bug...
> > It may be better to keep it simple though and drop either "posix" or
> > "fcntl". No need to add unneeded synonyms on a brand new mount option.
>
> Makes sense.. Trond: which one is more consistent?
I have a slight preference for 'posix'. fcntl is an extensible
interface, which currently supports at least two different types of lock
('posix' and 'lease').
> >> 'fcntl' - fcntl locks are local
> >> 'all' - Both flock locks and fcntl/posix locks are local
> >>
Cheers
Trond
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