lockd: call locks_release_private to cleanup per-filesystem state

For every lock request lockd creates a new file_lock object
in nlmsvc_setgrantargs() by copying the passed in file_lock with
locks_copy_lock(). A filesystem can attach it's own lock_operations
vector to the file_lock. It has to be cleaned up at the end of the
file_lock's life. However, lockd doesn't do it today, yet it
asserts in nlmclnt_release_lockargs() that the per-filesystem
state is clean.
This patch fixes it by exporting locks_release_private() and adding
it to nlmsvc_freegrantargs(), to be symmetrical to creating a
file_lock in nlmsvc_setgrantargs().

Signed-off-by: Felix Blyakher <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

Author: Felix Blyakher

fs/lockd/svclock.c

@@ -326,6 +326,8 @@ static void nlmsvc_freegrantargs(struct nlm_rqst *call)
 {
 	if (call->a_args.lock.oh.data != call->a_owner)
 		kfree(call->a_args.lock.oh.data);
+
+	locks_release_private(&call->a_args.lock.fl);
 }
 
 /*

fs/locks.c

@@ -151,7 +151,7 @@ static struct file_lock *locks_alloc_lock(void)
 	return kmem_cache_alloc(filelock_cache, GFP_KERNEL);
 }
 
-static void locks_release_private(struct file_lock *fl)
+void locks_release_private(struct file_lock *fl)
 {
 	if (fl->fl_ops) {
 		if (fl->fl_ops->fl_release_private)
@@ -165,6 +165,7 @@ static void locks_release_private(struct file_lock *fl)
 	}
 
 }
+EXPORT_SYMBOL_GPL(locks_release_private);
 
 /* Free a lock which is not in use. */
 static void locks_free_lock(struct file_lock *fl)

include/linux/fs.h

@@ -1108,6 +1108,7 @@ extern void locks_copy_lock(struct file_lock *, struct file_lock *);
 extern void __locks_copy_lock(struct file_lock *, const struct file_lock *);
 extern void locks_remove_posix(struct file *, fl_owner_t);
 extern void locks_remove_flock(struct file *);
+extern void locks_release_private(struct file_lock *);
 extern void posix_test_lock(struct file *, struct file_lock *);
 extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
 extern int posix_lock_file_wait(struct file *, struct file_lock *);