[ 21/89] xfs: Fix possible use-after-free with AIO

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

3.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@xxxxxxx>

commit 4b05d09c18d9aa62d2e7fb4b057f54e5a38963f5 upstream.

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

Signed-off-by: Jan Kara <jack@xxxxxxx>
CC: xfs@xxxxxxxxxxx
CC: Ben Myers <bpm@xxxxxxx>
Reviewed-by: Ben Myers <bpm@xxxxxxx>
Signed-off-by: Ben Myers <bpm@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/xfs/xfs_aops.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -86,11 +86,11 @@ xfs_destroy_ioend(
        }
 
        if (ioend->io_iocb) {
+               inode_dio_done(ioend->io_inode);
                if (ioend->io_isasync) {
                        aio_complete(ioend->io_iocb, ioend->io_error ?
                                        ioend->io_error : ioend->io_result, 0);
                }
-               inode_dio_done(ioend->io_inode);
        }
 
        mempool_free(ioend, xfs_ioend_pool);