On Tue, 07 Sep 2010 10:17:19 -0400 Trond Myklebust <Trond.Myklebust@xxxxxxxxxx> wrote: > On Mon, 2010-09-06 at 18:03 +0530, Suresh Jayaraman wrote: > > NFS clients since 2.6.12 support flock()locks by emulating the > > BSD-style locks in terms of POSIX byte range locks. So the NFS client > > does not allow to lock the same file using both flock() and fcntl > > byte-range locks. > > > > For some Windows applications which seem to use both share mode locks > > (flock()) and fcntl byte range locks sequentially on the same file, > > the locking is failing as the lock has already been acquired. i.e. the > > flock mapped as posix locks collide with actual byte range locks from > > the same process. The problem was observed on a setup with Windows > > clients accessing Excel files on a Samba exported share which is > > originally a NFS mount from a NetApp filer. Since kernels < 2.6.12 does > > not support flock, what was working (as flock locks were local) in > > older kernels is not working with newer kernels. > > > > This could be seen as a bug in the implementation of the windows > > application or a NFS client regression, but that is debatable. > > In the spirit of not breaking existing setups, this patch adds mount > > options "flock=local" that enables older flock behavior and > > "flock=fcntl" that allows the current flock behavior. > > So instead of having a special option for flock only, what say we rather > introduce an option of the form > > -olocal_lock= > > which can take the values 'none', 'flock', 'fcntl' (or 'posix'?) and > 'all'? > > Cheers > Trond Another thought -- we already have "-olock" and "-onolock" and we'll have to keep them for compatability. Maybe this should be "-oflock" and "-onoflock"? -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
