audit: set the name_len in audit_inode for parent lookups

Currently, this gets set mostly by happenstance when we call into
audit_inode_child. While that might be a little more efficient, it seems
wrong. If the syscall ends up failing before audit_inode_child ever gets
called, then you'll have an audit_names record that shows the full path
but has the parent inode info attached.

Fix this by passing in a parent flag when we call audit_inode that gets
set to the value of LOOKUP_PARENT. We can then fix up the pathname for
the audit entry correctly from the get-go.

While we're at it, clean up the no-op macro for audit_inode in the
!CONFIG_AUDITSYSCALL case.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 2640893..b11f517 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -456,6 +456,7 @@
 /* audit_names->type values */
 #define	AUDIT_TYPE_UNKNOWN	0	/* we don't know yet */
 #define	AUDIT_TYPE_NORMAL	1	/* a "normal" audit record */
+#define	AUDIT_TYPE_PARENT	2	/* a parent audit record */
 
 #ifdef CONFIG_AUDITSYSCALL
 /* These are defined in auditsc.c */
@@ -468,7 +469,8 @@
 extern void __audit_syscall_exit(int ret_success, long ret_value);
 extern void __audit_getname(const char *name);
 extern void audit_putname(const char *name);
-extern void __audit_inode(const char *name, const struct dentry *dentry);
+extern void __audit_inode(const char *name, const struct dentry *dentry,
+				unsigned int parent);
 extern void __audit_inode_child(const struct inode *parent,
 				const struct dentry *dentry);
 extern void __audit_seccomp(unsigned long syscall, long signr, int code);
@@ -505,9 +507,10 @@
 	if (unlikely(!audit_dummy_context()))
 		__audit_getname(name);
 }
-static inline void audit_inode(const char *name, const struct dentry *dentry) {
+static inline void audit_inode(const char *name, const struct dentry *dentry,
+				unsigned int parent) {
 	if (unlikely(!audit_dummy_context()))
-		__audit_inode(name, dentry);
+		__audit_inode(name, dentry, parent);
 }
 static inline void audit_inode_child(const struct inode *parent,
 				     const struct dentry *dentry) {
@@ -660,12 +663,14 @@
 { }
 static inline void audit_putname(const char *name)
 { }
-static inline void __audit_inode(const char *name, const struct dentry *dentry)
+static inline void __audit_inode(const char *name, const struct dentry *dentry,
+					unsigned int parent)
 { }
 static inline void __audit_inode_child(const struct inode *parent,
 					const struct dentry *dentry)
 { }
-static inline void audit_inode(const char *name, const struct dentry *dentry)
+static inline void audit_inode(const char *name, const struct dentry *dentry,
+				unsigned int parent)
 { }
 static inline void audit_inode_child(const struct inode *parent,
 				     const struct dentry *dentry)