Stanislav Kinsbursky adb6fa7ffe SUNRPC: fix races on PipeFS UMOUNT notifications
CPU#0                                   CPU#1
-----------------------------           -----------------------------
rpc_kill_sb
sn->pipefs_sb = NULL                    rpc_release_client
(UMOUNT_EVENT)                          rpc_free_auth
rpc_pipefs_event
rpc_get_client_for_event
!atomic_inc_not_zero(cl_count)
<skip the client>
                                        atomic_inc(cl_count)
                                        rpc_free_client
                                        rpc_clnt_remove_pipedir
                                        <skip client dir removing>

To fix this, this patch does the following:

1) Calls RPC_PIPEFS_UMOUNT notification with sn->pipefs_sb_lock being held.
2) Removes SUNRPC client from the list AFTER pipes destroying.
3) Doesn't hold RPC client on notification: if client in the list, then it
can't be destroyed while sn->pipefs_sb_lock in hold by notification caller.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-06-28 15:42:02 -04:00
..
2013-03-17 14:35:13 -04:00
2013-03-28 01:20:42 -04:00
2013-04-25 01:47:58 -04:00
2013-03-08 00:35:44 -05:00
2013-02-21 12:05:51 -08:00
2013-04-09 14:13:35 -04:00
2013-02-10 19:41:08 -05:00