orangefs: have ..._clean_interrupted_...() wait for copy to/from daemon

* turn all those list_del(&op->list) into list_del_init()
* don't pick ops that are already given up in control device
  ->read()/->write_iter().
* have orangefs_clean_interrupted_operation() notice if op is currently
  being copied to/from daemon (by said ->read()/->write_iter()) and
  wait for that to finish.
* when we are done copying to/from daemon and find that it had been
  given up while we were doing that, wake the waiting ..._clean_interrupted_...

As the result, we are guaranteed that orangefs_clean_interrupted_operation(op)
doesn't return until nobody else can see op.  Moreover, we don't need to play
with op refcounts anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
index d980240b0fa7..3f9e43066444 100644
--- a/fs/orangefs/waitqueue.c
+++ b/fs/orangefs/waitqueue.c
@@ -208,15 +208,20 @@ static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s
 	 * Called with op->lock held.
 	 */
 	op->op_state |= OP_VFS_STATE_GIVEN_UP;
-
-	if (op_state_waiting(op)) {
+	/* from that point on it can't be moved by anybody else */
+	if (list_empty(&op->list)) {
+		/* caught copying to/from daemon */
+		BUG_ON(op_state_serviced(op));
+		spin_unlock(&op->lock);
+		wait_for_completion(&op->waitq);
+	} else if (op_state_waiting(op)) {
 		/*
 		 * upcall hasn't been read; remove op from upcall request
 		 * list.
 		 */
 		spin_unlock(&op->lock);
 		spin_lock(&orangefs_request_list_lock);
-		list_del(&op->list);
+		list_del_init(&op->list);
 		spin_unlock(&orangefs_request_list_lock);
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "Interrupted: Removed op %p from request_list\n",
@@ -225,23 +230,16 @@ static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s
 		/* op must be removed from the in progress htable */
 		spin_unlock(&op->lock);
 		spin_lock(&htable_ops_in_progress_lock);
-		list_del(&op->list);
+		list_del_init(&op->list);
 		spin_unlock(&htable_ops_in_progress_lock);
 		gossip_debug(GOSSIP_WAIT_DEBUG,
 			     "Interrupted: Removed op %p"
 			     " from htable_ops_in_progress\n",
 			     op);
-	} else if (!op_state_serviced(op)) {
+	} else {
 		spin_unlock(&op->lock);
 		gossip_err("interrupted operation is in a weird state 0x%x\n",
 			   op->op_state);
-	} else {
-		/*
-		 * It is not intended for execution to flow here,
-		 * but having this unlock here makes sparse happy.
-		 */
-		gossip_err("%s: can't get here.\n", __func__);
-		spin_unlock(&op->lock);
 	}
 	reinit_completion(&op->waitq);
 }