[PATCH 2/2] ubifs: Allow O_DIRECT

[Richard Weinberger <richard@nod.at>]

Currently UBIFS does not support direct IO, but some applications
blindly use the O_DIRECT flag.
Instead of failing upon open() we can do better and fall back
to buffered IO.

Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: dedekind1@gmail.com
Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
 fs/ubifs/file.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index a3dfe2a..a61fe86 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1540,6 +1540,15 @@ static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
+/*
+ * For now fall back to buffered IO.
+ */
+static ssize_t ubifs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+				   loff_t offset)
+{
+	return 0;
+}
+
 const struct address_space_operations ubifs_file_address_operations = {
 	.readpage       = ubifs_readpage,
 	.writepage      = ubifs_writepage,
@@ -1548,6 +1557,7 @@ const struct address_space_operations ubifs_file_address_operations = {
 	.invalidatepage = ubifs_invalidatepage,
 	.set_page_dirty = ubifs_set_page_dirty,
 	.releasepage    = ubifs_releasepage,
+	.direct_IO	= ubifs_direct_IO,
 };
 
 const struct inode_operations ubifs_file_inode_operations = {
-- 
1.8.4.5