aio: make kiocb->private NUll in init_sync_kiocb()

Orabug: 14063941
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_write_iter().

We can't initialized this flag in ocfs2_file_write_iter() since
it may be invoked several times by do_sync_write(). So we initialize
it in init_sync_kiocb(), it's also useful for other similiar use of
it in the future.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>

diff --git a/include/linux/aio.h b/include/linux/aio.h
index 002a90adb751e0b8e224c4d90da2ea8755c8d24e..f918a209d92d2ebb79fc810b5870afad486a5131 100644 (file)
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -143,6 +143,7 @@ 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