[PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb()

[Junxiao Bi <junxiao.bi@oracle.com>]

Ocfs2 uses kiocb.*private as a flag of unsigned long size. In
commit a11f7e6 ocfs2: serialize unaligned aio, the unaligned
io flag is involved in it to serialize the unaligned aio. As
*private is not initialized in init_sync_kiocb() of do_sync_write(),
this unaligned io flag may be unexpectly set in an aligned dio.
And this will cause OCFS2_I(inode)->ip_unaligned_aio decreased
to -1 in ocfs2_dio_end_io(), thus the following unaligned dio
will hang forever at ocfs2_aiodio_wait() in ocfs2_file_aio_write().

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: stable@vger.kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
---
 include/linux/aio.h |    1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/aio.h b/include/linux/aio.h
index 2314ad8..b1a520e 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -140,6 +140,7 @@ struct kiocb {
 		(x)->ki_dtor = NULL;			\
 		(x)->ki_obj.tsk = tsk;			\
 		(x)->ki_user_data = 0;                  \
+		(x)->private = NULL;			\
 	} while (0)
 
 #define AIO_RING_MAGIC			0xa10a10a1
-- 
1.7.9.5