Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux

int fscrypt_file_open(struct inode *inode, struct file *filp)

{

	int err;

	struct dentry *dir;

	struct dentry *dentry, *dentry_parent;

	struct inode *inode_parent;

	err = fscrypt_require_key(inode);

	if (err)

		return err;

	dir = dget_parent(file_dentry(filp));

	if (IS_ENCRYPTED(d_inode(dir)) &&

	    !fscrypt_has_permitted_context(d_inode(dir), inode)) {

	dentry = file_dentry(filp);

	/*

	 * Getting a reference to the parent dentry is needed for the actual

	 * encryption policy comparison, but it's expensive on multi-core

	 * systems.  Since this function runs on unencrypted files too, start

	 * with a lightweight RCU-mode check for the parent directory being

	 * unencrypted (in which case it's fine for the child to be either

	 * unencrypted, or encrypted with any policy).  Only continue on to the

	 * full policy check if the parent directory is actually encrypted.

	 */

	rcu_read_lock();

	dentry_parent = READ_ONCE(dentry->d_parent);

	inode_parent = d_inode_rcu(dentry_parent);

	if (inode_parent != NULL && !IS_ENCRYPTED(inode_parent)) {

		rcu_read_unlock();

		return 0;

	}

	rcu_read_unlock();

	dentry_parent = dget_parent(dentry);

	if (!fscrypt_has_permitted_context(d_inode(dentry_parent), inode)) {

		fscrypt_warn(inode,

			     "Inconsistent encryption context (parent directory: %lu)",

			     d_inode(dir)->i_ino);

			     d_inode(dentry_parent)->i_ino);

		err = -EPERM;

	}

	dput(dir);

	dput(dentry_parent);

	return err;

}

EXPORT_SYMBOL_GPL(fscrypt_file_open);