1 files changed, 22 insertions, 0 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 7ddddf2e2504..5a5a87240fe2 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3663,6 +3663,27 @@ void cifs_oplock_break(struct work_struct *work)
         }
 }
 
+/*
+ * The presence of cifs_direct_io() in the address space ops vector
+ * allowes open() O_DIRECT flags which would have failed otherwise.
+ *
+ * In the non-cached mode (mount with cache=none), we shunt off direct read and write requests
+ * so this method should never be called.
+ *
+ * Direct IO is not yet supported in the cached mode. 
+ */
+static ssize_t
+cifs_direct_io(int rw, struct kiocb *iocb, const struct iovec *iov,
+               loff_t pos, unsigned long nr_segs)
+{
+        /*
+         * FIXME
+         * Eventually need to support direct IO for non forcedirectio mounts
+         */
+        return -EINVAL;
+}
+
+
 const struct address_space_operations cifs_addr_ops = {
         .readpage = cifs_readpage,
         .readpages = cifs_readpages,
@@ -3672,6 +3693,7 @@ const struct address_space_operations cifs_addr_ops = {
         .write_end = cifs_write_end,
         .set_page_dirty = __set_page_dirty_nobuffers,
         .releasepage = cifs_release_page,
+        .direct_IO = cifs_direct_io,
         .invalidatepage = cifs_invalidate_page,
         .launder_page = cifs_launder_page,
 };