CRED: Pass credentials through dentry_open()

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 64d2ba9..fd63071 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -115,6 +115,7 @@
  */
 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 {
+	const struct cred *cred = current_cred();
 	struct ecryptfs_inode_info *inode_info =
 		ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
 	int rc = 0;
@@ -127,7 +128,7 @@
 
 		lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 		rc = ecryptfs_privileged_open(&inode_info->lower_file,
-						     lower_dentry, lower_mnt);
+					      lower_dentry, lower_mnt, cred);
 		if (rc || IS_ERR(inode_info->lower_file)) {
 			printk(KERN_ERR "Error opening lower persistent file "
 			       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "