Wrapfs: add read_iter/write_iter opeations

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Mengyang Li <li.mengyang@stonybrook.edu>

diff --git a/fs/wrapfs/file.c b/fs/wrapfs/file.c
index 4c5da2ae46553eccb07413f5cdb1bf30d3fba36b..6086cce83a50551bb829fd5ff999ef6404b92cf9 100644 (file)
--- a/fs/wrapfs/file.c
+++ b/fs/wrapfs/file.c
@@ -329,6 +329,55 @@ out:
        return err;
 }
 
+/*
+ * Wrapfs read_iter, redirect modified iocb to lower read_iter
+ */
+ssize_t
+wrapfs_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       int err;
+       struct file *file = iocb->ki_filp, *lower_file;
+
+       lower_file = wrapfs_lower_file(file);
+       if (!lower_file->f_op->read_iter) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       get_file(lower_file); /* prevent lower_file from being released */
+       iocb->ki_filp = lower_file;
+       err = lower_file->f_op->read_iter(iocb, iter);
+       /* ? wait IO finish to update atime as ecryptfs ? */
+       iocb->ki_filp = file;
+       fput(lower_file);
+out:
+       return err;
+}
+
+/*
+ * Wrapfs write_iter, redirect modified iocb to lower write_iter
+ */
+ssize_t
+wrapfs_write_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       int err;
+       struct file *file = iocb->ki_filp, *lower_file;
+
+       lower_file = wrapfs_lower_file(file);
+       if (!lower_file->f_op->write_iter) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       get_file(lower_file); /* prevent lower_file from being released */
+       iocb->ki_filp = lower_file;
+       err = lower_file->f_op->write_iter(iocb, iter);
+       iocb->ki_filp = file;
+       fput(lower_file);
+out:
+       return err;
+}
+
 const struct file_operations wrapfs_main_fops = {
        .llseek         = generic_file_llseek,
        .read           = wrapfs_read,
@@ -345,6 +394,8 @@ const struct file_operations wrapfs_main_fops = {
        .fasync         = wrapfs_fasync,
        .aio_read       = wrapfs_aio_read,
        .aio_write      = wrapfs_aio_write,
+       .read_iter      = wrapfs_read_iter,
+       .write_iter     = wrapfs_write_iter,
 };
 
 /* trimmed directory options */