[PATCH 5.1 30/70] NFSv4.1: Fix bug only first CB_NOTIFY_LOCK is handled

From: Greg Kroah-Hartman
Date: Sun Jun 09 2019 - 12:49:28 EST


From: Yihao Wu <wuyihao@xxxxxxxxxxxxxxxxx>

commit ba851a39c9703f09684a541885ed176f8fb7c868 upstream.

When a waiter is waked by CB_NOTIFY_LOCK, it will retry
nfs4_proc_setlk(). The waiter may fail to nfs4_proc_setlk() and sleep
again. However, the waiter is already removed from clp->cl_lock_waitq
when handling CB_NOTIFY_LOCK in nfs4_wake_lock_waiter(). So any
subsequent CB_NOTIFY_LOCK won't wake this waiter anymore. We should
put the waiter back to clp->cl_lock_waitq before retrying.

Cc: stable@xxxxxxxxxxxxxxx #4.9+
Signed-off-by: Yihao Wu <wuyihao@xxxxxxxxxxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/nfs4proc.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6922,20 +6922,22 @@ nfs4_retry_setlk(struct nfs4_state *stat
init_wait(&wait);
wait.private = &waiter;
wait.func = nfs4_wake_lock_waiter;
- add_wait_queue(q, &wait);

while(!signalled()) {
+ add_wait_queue(q, &wait);
status = nfs4_proc_setlk(state, cmd, request);
- if ((status != -EAGAIN) || IS_SETLK(cmd))
+ if ((status != -EAGAIN) || IS_SETLK(cmd)) {
+ finish_wait(q, &wait);
break;
+ }

status = -ERESTARTSYS;
freezer_do_not_count();
wait_woken(&wait, TASK_INTERRUPTIBLE, NFS4_LOCK_MAXTIMEOUT);
freezer_count();
+ finish_wait(q, &wait);
}

- finish_wait(q, &wait);
return status;
}
#else /* !CONFIG_NFS_V4_1 */