Security: Add hook to calculate context based on a negative dentry.

There is a time where we need to calculate a context without the
inode having been created yet. To do this we take the negative dentry and
calculate a context based on the process and the parent directory contexts.

Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/security/security.c b/security/security.c
index a3dce87..0fe2b2e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -12,6 +12,7 @@
  */
 
 #include <linux/capability.h>
+#include <linux/dcache.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -324,6 +325,15 @@
 	security_ops->inode_free_security(inode);
 }
 
+int security_dentry_init_security(struct dentry *dentry, int mode,
+					struct qstr *name, void **ctx,
+					u32 *ctxlen)
+{
+	return security_ops->dentry_init_security(dentry, mode, name,
+							ctx, ctxlen);
+}
+EXPORT_SYMBOL(security_dentry_init_security);
+
 int security_inode_init_security(struct inode *inode, struct inode *dir,
 				 const struct qstr *qstr,
 				 const initxattrs initxattrs, void *fs_data)