[PATCH AUTOSEL 5.10 65/65] minix: fix bug when opening a file with O_DIRECT

[Sasha Levin]

From: Qinghua Jin <qhjin.dev@xxxxxxxxx>

[ Upstream commit 9ce3c0d26c42d279b6c378a03cd6a61d828f19ca ]

Testcase:
1. create a minix file system and mount it
2. open a file on the file system with O_RDWR|O_CREAT|O_TRUNC|O_DIRECT
3. open fails with -EINVAL but leaves an empty file behind. All other
   open() failures don't leave the failed open files behind.

It is hard to check the direct_IO op before creating the inode.  Just as
ext4 and btrfs do, this patch will resolve the issue by allowing to
create the file with O_DIRECT but returning error when writing the file.

Link: https://lkml.kernel.org/r/20220107133626.413379-1-qhjin.dev@xxxxxxxxx
Signed-off-by: Qinghua Jin <qhjin.dev@xxxxxxxxx>
Reported-by: Colin Ian King <colin.king@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/minix/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 34f546404aa1..e938f5b1e4b9 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -446,7 +446,8 @@ static const struct address_space_operations minix_aops = {
 	.writepage = minix_writepage,
 	.write_begin = minix_write_begin,
 	.write_end = generic_write_end,
-	.bmap = minix_bmap
+	.bmap = minix_bmap,
+	.direct_IO = noop_direct_IO
 };
 
 static const struct inode_operations minix_symlink_inode_operations = {
-- 
2.34.1