+ * Read from a file (through the page cache).
+ */
+static ssize_t ll_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct vvp_io_args *args;
+ struct lu_env *env;
+ ssize_t result;
+ int refcheck;
+
+ env = cl_env_get(&refcheck);
+ if (IS_ERR(env))
+ return PTR_ERR(env);
+
+ args = ll_env_args(env, IO_NORMAL);
+ args->u.normal.via_iter = to;
+ args->u.normal.via_iocb = iocb;
+
+ result = ll_file_io_generic(env, args, iocb->ki_filp, CIT_READ,
+ &iocb->ki_pos, iov_iter_count(to));
+ cl_env_put(env, &refcheck);
+ return result;
+}
+
+/*
+ * Write to a file (through the page cache).
+ */
+static ssize_t ll_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct vvp_io_args *args;
+ struct lu_env *env;
+ ssize_t result;
+ int refcheck;
+
+ env = cl_env_get(&refcheck);
+ if (IS_ERR(env))
+ return PTR_ERR(env);
+
+ args = ll_env_args(env, IO_NORMAL);
+ args->u.normal.via_iter = from;
+ args->u.normal.via_iocb = iocb;
+
+ result = ll_file_io_generic(env, args, iocb->ki_filp, CIT_WRITE,
+ &iocb->ki_pos, iov_iter_count(from));
+ cl_env_put(env, &refcheck);
+ return result;
+}
+
+#ifndef HAVE_FILE_OPERATIONS_READ_WRITE_ITER
+/*