On Wed, Jan 21, 2009 at 09:26:08PM -0500, Jeff Layton wrote: > On Wed, 21 Jan 2009 18:42:39 -0500 > "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote: > > > On Wed, Jan 21, 2009 at 11:34:50AM -0500, Jeff Layton wrote: > > > dlm_posix_get fills out the relevant fields in the file_lock before > > > returning when there is a lock conflict, but doesn't clean out any of > > > the other fields in the file_lock. > > > > > > When nfsd does a NFSv4 lockt call, it sets the fl_lmops to > > > nfsd_posix_mng_ops before calling the lower fs. When the lock comes back > > > after testing a lock on GFS2, it still has that field set. This confuses > > > nfsd into thinking that the file_lock is a nfsd4 lock. > > > > I think of the lock system as supporting two types of objects, both > > stored in "struct lock"'s: > > > > - Heavyweight locks: these have callbacks set and the filesystem > > or lock manager could in theory have some private data > > associated with them, so it's important that the appropriate > > callbacks be called when they're released or copied. These > > are what are actually passed to posix_lock_file() and kept on > > the inode lock lists. > > - Lightweight locks: just start, end, pid, flags, and type, with > > everything zeroed out and/or ignored. > > > > I don't see any reason why the lock passed into dlm_posix_get() needs to > > be a heavyweight lock. In any case, if it were, then dlm_posix_get() > > would need to release the passed-in-lock before initializing the new one > > that it's returning. > > > > > From what I can tell, dlm_posix_lock is always passed a "lightweight" > lock. Right, so in your second patch, I think the fl_lmops assignment in nfsd4_lockt should also be removed. > > The returned lock should probably also be a lightweight lock that's a > > copy of whatever conflicting lock was found; otherwise we need to > > require the caller to for example release the thing correctly. > > > > That's unfortunate for nfsv4 since that doesn't allow returning the > > lockowner information to the client. But it's not terribly important > > to get that right. > > > > Since gfs2 doesn't report the conflicting lock, I guess we just punt and > > return a copy of the passed-in lock, OK. > > > > I'm not sure I follow you here... > > GFS2/DLM does report the conflicting lock. It's just that when there is > one, it's only overwriting some of the fields in the lock. Whoops, sorry, OK. > The idea with this patch is to basically try and make dlm_posix_get() > fill out the same fields as __locks_copy_lock() and make sure the rest > are initialized. Yes, this patch seems fine. I'm less sure of the second. --b. -- 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
