lockd: Convert NLM service fl_owner to nlm_lockowner

Do as the NLM client: allocate and track a struct nlm_lockowner for use as
the fl_owner for locks created by the NLM sever. This allows us to keep
the svid within this structure for matching locks, and will allow us to
track the pid of lockd in a future patch. It should also allow easier
reference of the nlm_host in conflicting locks, and simplify lock hashing
and comparison.

Signed-off-by: Benjamin Coddington <[e-mail]>
[[e-mail]: fix type of some error returns]
Signed-off-by: J. Bruce Fields <[e-mail]>

fs/lockd/svc4proc.c

···
 
 		/* Set up the missing parts of the file_lock structure */
 		lock->fl.fl_file  = file->f_file;
-		lock->fl.fl_owner = (fl_owner_t) host;
 		lock->fl.fl_lmops = &nlmsvc_lock_operations;
+		nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+		if (!lock->fl.fl_owner) {
+			/* lockowner allocation has failed */
+			nlmsvc_release_host(host);
+			return nlm_lck_denied_nolocks;
+		}
 	}
 
 	return 0;
···
 	else
 		dprintk("lockd: TEST4        status %d\n", ntohl(resp->status));
 
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rc;
···
 	else
 		dprintk("lockd: LOCK         status %d\n", ntohl(resp->status));
 
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rc;
···
 	resp->status = nlmsvc_cancel_blocked(SVC_NET(rqstp), file, &argp->lock);
 
 	dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = nlmsvc_unlock(SVC_NET(rqstp), file, &argp->lock);
 
 	dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = nlmsvc_share_file(host, file, argp);
 
 	dprintk("lockd: SHARE         status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = nlmsvc_unshare_file(host, file, argp);
 
 	dprintk("lockd: UNSHARE       status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;

fs/lockd/svclock.c

···
 	mutex_unlock(&file->f_mutex);
 }
 
+static struct nlm_lockowner *
+nlmsvc_get_lockowner(struct nlm_lockowner *lockowner)
+{
+	refcount_inc(&lockowner->count);
+	return lockowner;
+}
+
+static void nlmsvc_put_lockowner(struct nlm_lockowner *lockowner)
+{
+	if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
+		return;
+	list_del(&lockowner->list);
+	spin_unlock(&lockowner->host->h_lock);
+	nlmsvc_release_host(lockowner->host);
+	kfree(lockowner);
+}
+
+static struct nlm_lockowner *__nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+	struct nlm_lockowner *lockowner;
+	list_for_each_entry(lockowner, &host->h_lockowners, list) {
+		if (lockowner->pid != pid)
+			continue;
+		return nlmsvc_get_lockowner(lockowner);
+	}
+	return NULL;
+}
+
+static struct nlm_lockowner *nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+	struct nlm_lockowner *res, *new = NULL;
+
+	spin_lock(&host->h_lock);
+	res = __nlmsvc_find_lockowner(host, pid);
+
+	if (res == NULL) {
+		spin_unlock(&host->h_lock);
+		new = kmalloc(sizeof(*res), GFP_KERNEL);
+		spin_lock(&host->h_lock);
+		res = __nlmsvc_find_lockowner(host, pid);
+		if (res == NULL && new != NULL) {
+			res = new;
+			/* fs/locks.c will manage the refcount through lock_ops */
+			refcount_set(&new->count, 1);
+			new->pid = pid;
+			new->host = nlm_get_host(host);
+			list_add(&new->list, &host->h_lockowners);
+			new = NULL;
+		}
+	}
+
+	spin_unlock(&host->h_lock);
+	kfree(new);
+	return res;
+}
+
+void
+nlmsvc_release_lockowner(struct nlm_lock *lock)
+{
+	if (lock->fl.fl_owner)
+		nlmsvc_put_lockowner(lock->fl.fl_owner);
+}
+
+static void nlmsvc_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+	struct nlm_lockowner *nlm_lo = (struct nlm_lockowner *)fl->fl_owner;
+	new->fl_owner = nlmsvc_get_lockowner(nlm_lo);
+}
+
+static void nlmsvc_locks_release_private(struct file_lock *fl)
+{
+	nlmsvc_put_lockowner((struct nlm_lockowner *)fl->fl_owner);
+}
+
+const struct file_lock_operations nlmsvc_lock_ops = {
+	.fl_copy_lock = nlmsvc_locks_copy_lock,
+	.fl_release_private = nlmsvc_locks_release_private,
+};
+
+void nlmsvc_locks_init_private(struct file_lock *fl, struct nlm_host *host,
+						pid_t pid)
+{
+	fl->fl_owner = nlmsvc_find_lockowner(host, pid);
+	if (fl->fl_owner != NULL)
+		fl->fl_ops = &nlmsvc_lock_ops;
+}
+
 /*
  * Initialize arguments for GRANTED call. The nlm_rqst structure
  * has been cleared already.
···
 {
 	int			error;
 	__be32			ret;
+	struct nlm_lockowner	*test_owner;
 
 	dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
 				locks_inode(file->f_file)->i_sb->s_id,
···
 		ret = nlm_lck_denied_grace_period;
 		goto out;
 	}
+
+	/* If there's a conflicting lock, remember to clean up the test lock */
+	test_owner = (struct nlm_lockowner *)lock->fl.fl_owner;
 
 	error = vfs_test_lock(file->f_file, &lock->fl);
 	if (error) {
···
 	conflock->fl.fl_start = lock->fl.fl_start;
 	conflock->fl.fl_end = lock->fl.fl_end;
 	locks_release_private(&lock->fl);
+
+	/* Clean up the test lock */
+	lock->fl.fl_owner = NULL;
+	nlmsvc_put_lockowner(test_owner);
+
 	ret = nlm_lck_denied;
 out:
 	return ret;

fs/lockd/svcproc.c

···
 
 		/* Set up the missing parts of the file_lock structure */
 		lock->fl.fl_file  = file->f_file;
-		lock->fl.fl_owner = (fl_owner_t) host;
 		lock->fl.fl_lmops = &nlmsvc_lock_operations;
+		nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+		if (!lock->fl.fl_owner) {
+			/* lockowner allocation has failed */
+			nlmsvc_release_host(host);
+			return nlm_lck_denied_nolocks;
+		}
 	}
 
 	return 0;
···
 		dprintk("lockd: TEST          status %d vers %d\n",
 			ntohl(resp->status), rqstp->rq_vers);
 
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rc;
···
 	else
 		dprintk("lockd: LOCK         status %d\n", ntohl(resp->status));
 
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rc;
···
 	resp->status = cast_status(nlmsvc_cancel_blocked(net, file, &argp->lock));
 
 	dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = cast_status(nlmsvc_unlock(net, file, &argp->lock));
 
 	dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = cast_status(nlmsvc_share_file(host, file, argp));
 
 	dprintk("lockd: SHARE         status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;
···
 	resp->status = cast_status(nlmsvc_unshare_file(host, file, argp));
 
 	dprintk("lockd: UNSHARE       status %d\n", ntohl(resp->status));
+	nlmsvc_release_lockowner(&argp->lock);
 	nlmsvc_release_host(host);
 	nlm_release_file(file);
 	return rpc_success;

fs/lockd/svcsubs.c

···
 		/* update current lock count */
 		file->f_locks++;
 
-		lockhost = (struct nlm_host *) fl->fl_owner;
+		lockhost = ((struct nlm_lockowner *)fl->fl_owner)->host;
 		if (match(lockhost, host)) {
 			struct file_lock lock = *fl;
 

fs/lockd/xdr.c

···
 	lock->svid  = ntohl(*p++);
 
 	locks_init_lock(fl);
-	fl->fl_owner = current->files;
 	fl->fl_pid   = (pid_t)lock->svid;
 	fl->fl_flags = FL_POSIX;
 	fl->fl_type  = F_RDLCK;		/* as good as anything else */

fs/lockd/xdr4.c

···
 	lock->svid  = ntohl(*p++);
 
 	locks_init_lock(fl);
-	fl->fl_owner = current->files;
 	fl->fl_pid   = (pid_t)lock->svid;
 	fl->fl_flags = FL_POSIX;
 	fl->fl_type  = F_RDLCK;		/* as good as anything else */

include/linux/lockd/lockd.h

···
 					nlm_host_match_fn_t match);
 void		  nlmsvc_grant_reply(struct nlm_cookie *, __be32);
 void		  nlmsvc_release_call(struct nlm_rqst *);
+void		  nlmsvc_locks_init_private(struct file_lock *, struct nlm_host *, pid_t);
 
 /*
  * File handling for the server personality
···
 __be32		  nlm_lookup_file(struct svc_rqst *, struct nlm_file **,
 					struct nfs_fh *);
 void		  nlm_release_file(struct nlm_file *);
+void		  nlmsvc_release_lockowner(struct nlm_lock *);
 void		  nlmsvc_mark_resources(struct net *);
 void		  nlmsvc_free_host_resources(struct nlm_host *);
 void		  nlmsvc_invalidate_all(void);