From:   Qinghua Jin <qhjin.dev@gmail.com>
Cc:     Qinghua Jin <qhjin.dev@gmail.com>,
        Colin Ian King <colin.king@intel.com>,
        Jan Kara <jack@suse.cz>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        James Morris <jamorris@linux.microsoft.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2] minix: fix bug when opening a file with O_DIRECT
Date:   Fri,  7 Jan 2022 21:36:25 +0800
Message-Id: <20220107133626.413379-1-qhjin.dev@gmail.com>
In-Reply-To: <20220107113254.bkfpud453zivotov@wittgenstein>
References: <20220107113254.bkfpud453zivotov@wittgenstein>
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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.

Reported-by: Colin Ian King <colin.king@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Qinghua Jin <qhjin.dev@gmail.com>
---
 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 a71f1cf894b9..d4bd94234ef7 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -447,7 +447,8 @@ 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 = {
-- 
2.30.2