On Wed, 5 Oct 2011 13:24:59 +0400 Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote: > 2011/10/4 J. Bruce Fields <bfields@xxxxxxxxxxxx>: > > On Tue, Oct 04, 2011 at 06:54:51AM -0400, Jeff Layton wrote: > >> I think this is tantamount to insisting that applications be specially > >> written for cifs.ko if they want to do locking. > >> > >> The larger goal for cifs.ko (as I see it) is to allow applications to > >> mostly run unchanged on top of windows servers. Naturally, this is > >> impossible since windows doesn't follow POSIX semantics, so the best we > >> can do is closely approximate it. > >> > >> There's certainly room for improvement here, but what you're proposing > >> sounds like a step backward from that goal. It will break a lot of > >> existing applications that run successfully on top of cifs.ko today. > > > > Right. You can tell which kind of locking the application wants by the > > interface it's using. If the application is using fcntl F_GETLK, > > F_SETLK, F_SETLKW, then chances are it was written assuming posix > > semantics, so all we can do is emulate those as best as possible. > > > > If there are applications that need want the Windows semantics, then > > we'd need to provide a new lock interface which promises them exactly > > that. > > > > --b. > > > > Ok, I understand your and Jeff's idea - it's better to support POSIX > at least partly than doesn't support it at all. > > I don't think that we need VFS changes for the new mode, because it is > cifs feature only. All that we need is to support this for cifs - so, > it can be a new mount option or the existing one - now we have > 'forcemand' mount option (that switch on mandatory locking even if the > server support POSIX one) that can includes such a change. What do you > think about it? > I'm not a fan of adding more mount-option enabled hacks to cifs to support wine. If wine or other applications need windows semantics, then I would prefer to see you add proper vfs-level interfaces to provide them. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
