vfs: Introduce vop_eperm

vop_eperm allows more code reuse (suggested by Glauber Costa)

Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

fs/devfs/devfs_vnops.c

@@ -187,12 +187,6 @@ devfs_readdir(struct vnode *vp, struct file *fp, struct dirent *dir)
 	return 0;
 }
 
-static int
-devfs_link(struct vnode *tdvp, struct vnode *svp, char *name)
-{
-	return EPERM;
-}
-
 int
 devfs_init(void)
 {
@@ -216,6 +210,7 @@ devfs_init(void)
 #define devfs_setattr	((vnop_setattr_t)vop_nullop)
 #define devfs_inactive	((vnop_inactive_t)vop_nullop)
 #define devfs_truncate	((vnop_truncate_t)vop_nullop)
+#define devfs_link	((vnop_link_t)vop_eperm)
 
 /*
  * vnode operations

fs/ramfs/ramfs_vnops.c

@@ -431,12 +431,6 @@ ramfs_readdir(struct vnode *vp, struct file *fp, struct dirent *dir)
 	return 0;
 }
 
-static int
-ramfs_link(struct vnode *tdvp, struct vnode *svp, char *name)
-{
-	return EPERM;
-}
-
 int
 ramfs_init(void)
 {
@@ -451,6 +445,7 @@ ramfs_init(void)
 #define ramfs_getattr	((vnop_getattr_t)vop_nullop)
 #define ramfs_setattr	((vnop_setattr_t)vop_nullop)
 #define ramfs_inactive	((vnop_inactive_t)vop_nullop)
+#define ramfs_link	((vnop_link_t)vop_eperm)
 
 /*
  * vnode operations

fs/vfs/vfs_vnode.c

@@ -481,6 +481,13 @@ vop_einval(void)
 	return EINVAL;
 }
 
+int
+vop_eperm(void)
+{
+
+	return EPERM;
+}
+
 /*
  * vnode_init() is called once (from vfs_init)
  * in initialization.

include/osv/vnode.h

@@ -190,6 +190,7 @@ struct vnops {
 
 int	 vop_nullop(void);
 int	 vop_einval(void);
+int	 vop_eperm(void);
 struct vnode *vn_lookup(struct mount *, char *);
 void	 vn_lock(struct vnode *);
 void	 vn_unlock(struct vnode *);