[PATCH] knfsd: locks: flag NFSv4-owned locks

Use the fl_lmops field to identify which locks are ours, instead of trying to
look them up in our private hash.  This is safer and more efficient.

Earlier versions of this patch used a lock flag instead, but Trond pointed out
that adding a new flag for each lock manager wasn't going to scale well, and
suggested this approach instead; a separate patch converts lockd to using
fl_lmops in the same way.

In the NFSv4 case this looks like a bit of a hack, since the NFSv4 server
isn't currently actually defining a lock_manager_operations struct, so we end
up defining one *just* to serve as a cookie to identify our locks.

But it works, and we actually do expect to start using the
lock_manager_operations at some point anyway.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfs4state.c

@@ -2495,36 +2495,27 @@ nfs4_transform_lock_offset(struct file_lock *lock)
 		lock->fl_end = OFFSET_MAX;
 }
 
-static int
-nfs4_verify_lock_stateowner(struct nfs4_stateowner *sop, unsigned int hashval)
-{
-	struct nfs4_stateowner *local = NULL;
-	int status = 0;
-
-	if (hashval >= LOCK_HASH_SIZE)
-		goto out;
-	list_for_each_entry(local, &lock_ownerid_hashtbl[hashval], so_idhash) {
-		if (local == sop) {
-			status = 1;
-			goto out;
-		}
-	}
-out:
-	return status;
-}
-
+/* Hack!: For now, we're defining this just so we can use a pointer to it
+ * as a unique cookie to identify our (NFSv4's) posix locks. */
+struct lock_manager_operations nfsd_posix_mng_ops  = {
+};
 
 static inline void
 nfs4_set_lock_denied(struct file_lock *fl, struct nfsd4_lock_denied *deny)
 {
-	struct nfs4_stateowner *sop = (struct nfs4_stateowner *) fl->fl_owner;
-	unsigned int hval = lockownerid_hashval(sop->so_id);
+	struct nfs4_stateowner *sop;
+	unsigned int hval;
 
-	deny->ld_sop = NULL;
-	if (nfs4_verify_lock_stateowner(sop, hval)) {
+	if (fl->fl_lmops == &nfsd_posix_mng_ops) {
+		sop = (struct nfs4_stateowner *) fl->fl_owner;
+		hval = lockownerid_hashval(sop->so_id);
 		kref_get(&sop->so_ref);
 		deny->ld_sop = sop;
 		deny->ld_clientid = sop->so_client->cl_clientid;
+	} else {
+		deny->ld_sop = NULL;
+		deny->ld_clientid.cl_boot = 0;
+		deny->ld_clientid.cl_id = 0;
 	}
 	deny->ld_start = fl->fl_start;
 	deny->ld_length = ~(u64)0;
@@ -2736,6 +2727,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock
 	file_lock.fl_pid = current->tgid;
 	file_lock.fl_file = filp;
 	file_lock.fl_flags = FL_POSIX;
+	file_lock.fl_lmops = &nfsd_posix_mng_ops;
 
 	file_lock.fl_start = lock->lk_offset;
 	if ((lock->lk_length == ~(u64)0) || 
@@ -2841,6 +2833,7 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock
 		file_lock.fl_owner = (fl_owner_t)lockt->lt_stateowner;
 	file_lock.fl_pid = current->tgid;
 	file_lock.fl_flags = FL_POSIX;
+	file_lock.fl_lmops = &nfsd_posix_mng_ops;
 
 	file_lock.fl_start = lockt->lt_offset;
 	if ((lockt->lt_length == ~(u64)0) || LOFF_OVERFLOW(lockt->lt_offset, lockt->lt_length))
@@ -2900,6 +2893,7 @@ nfsd4_locku(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_lock
 	file_lock.fl_pid = current->tgid;
 	file_lock.fl_file = filp;
 	file_lock.fl_flags = FL_POSIX; 
+	file_lock.fl_lmops = &nfsd_posix_mng_ops;
 	file_lock.fl_start = locku->lu_offset;
 
 	if ((locku->lu_length == ~(u64)0) || LOFF_OVERFLOW(locku->lu_offset, locku->lu_length))