From: Hou Tao <houtao1@huawei.com>
Date: Fri, 8 Mar 2019 00:29:19 +0000 (-0800)
Subject: fat: enable .splice_write to support splice on O_DIRECT file
X-Git-Tag: v5.1-rc1~118^2~35
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=67ceb1eca0acc045c9ef170a05f58fd710063967;p=linux-block.git

fat: enable .splice_write to support splice on O_DIRECT file

Now splice() on O_DIRECT-opened fat file will return -EFAULT, that is
because the default .splice_write, namely default_file_splice_write(),
will construct an ITER_KVEC iov_iter and dio_refill_pages() in dio path
can not handle it.

Fix it by implementing .splice_write through iter_file_splice_write().

Spotted by xfs-tests generic/091.

Link: http://lkml.kernel.org/r/20190210094754.56355-1-houtao1@huawei.com
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/fat/file.c b/fs/fat/file.c
index 13935ee99e1e..b3bed32946b1 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -214,6 +214,7 @@ const struct file_operations fat_file_operations = {
 #endif
 	.fsync		= fat_file_fsync,
 	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
 	.fallocate	= fat_fallocate,
 };