On Thu, Jan 8, 2015 at 9:37 PM, Anand Avati <[email protected]> wrote:
> Note that the mandatory locks available in the locks translator is just > the mandatory extensions for posix locks - at least one of the apps must be > using locks to begin with. Linux mandatory locking definition seems to convey exactly the above meaning [1]. <extract> 4. Semantics ------------ 1. Mandatory locks can only be applied via the fcntl()/lockf() locking interface - in other words the System V/POSIX interface. BSD style locks using flock() never result in a mandatory lock. </extract> [1] https://www.kernel.org/doc/Documentation/filesystems/mandatory-locking.txt What Harmeet is asking for is something different - automatic exclusive > access to edit files. i.e, if one app has opened a file for editing, other > apps which attempt an open must either fail (EBUSY) or block till the first > app closes. We need to treat open(O_RDONLY) as a read lock and > open(O_RDWR|O_WRONLY) as a write lock request (essentially an auto applied > oplock). This is something gluster does not yet have. > > Thanks > > On Thu Jan 08 2015 at 2:49:29 AM Raghavendra Gowdappa <[email protected]> > wrote: > >> >> >> ----- Original Message ----- >> > From: "Raghavendra Gowdappa" <[email protected]> >> > To: "Harmeet Kalsi" <[email protected]> >> > Cc: "[email protected]" <[email protected]> >> > Sent: Thursday, January 8, 2015 4:12:44 PM >> > Subject: Re: [Gluster-devel] mandatory lock >> > >> > >> > >> > ----- Original Message ----- >> > > From: "Harmeet Kalsi" <[email protected]> >> > > To: "[email protected]" <[email protected]> >> > > Sent: Wednesday, January 7, 2015 5:55:43 PM >> > > Subject: [Gluster-devel] mandatory lock >> > > >> > > Dear All. >> > > Would it be possible for someone to guide me in the right direction to >> > > enable >> > > the mandatory lock on a volume please. >> > > At the moment two clients can edit the same file at the same time >> which is >> > > causing issues. >> > >> > I see code related to mandatory locking in posix-locks xlator >> (pl_writev, >> > pl_truncate etc). To enable it you've to set "option mandatory-locks >> yes" in >> > posix-locks xlator loaded on bricks >> > (/var/lib/glusterd/vols/<volname>/*.vol). We've no way to set this >> option >> > through gluster cli. Also, I am not sure to what extent this feature is >> > tested/used till now. You can try it out and please let us know whether >> it >> > worked for you :). >> >> If mandatory locking doesn't work for you, can you modify your >> application to use advisory locking, since advisory locking is tested well >> and being used for long time? >> >> > >> > > Many thanks in advance >> > > Kind Regards >> > > >> > > _______________________________________________ >> > > Gluster-devel mailing list >> > > [email protected] >> > > http://www.gluster.org/mailman/listinfo/gluster-devel >> > > >> > _______________________________________________ >> > Gluster-devel mailing list >> > [email protected] >> > http://www.gluster.org/mailman/listinfo/gluster-devel >> > >> _______________________________________________ >> Gluster-devel mailing list >> [email protected] >> http://www.gluster.org/mailman/listinfo/gluster-devel >> > > _______________________________________________ > Gluster-devel mailing list > [email protected] > http://www.gluster.org/mailman/listinfo/gluster-devel > > -- Raghavendra G
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