btrfs: unify error handling for ticket flushing

Currently we handle the cleanup of errored out tickets in both the
priority flush path and the normal flushing path.  This is the same code
in both places, so just refactor so we don't duplicate the cleanup work.
Signed-off-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/space-info.c

@@ -878,20 +878,19 @@ static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
 	} while (flush_state < ARRAY_SIZE(priority_flush_states));
 }
 
-static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
-			       struct btrfs_space_info *space_info,
-			       struct reserve_ticket *ticket)
+static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info,
+				struct reserve_ticket *ticket)
 
 {
 	DEFINE_WAIT(wait);
-	u64 reclaim_bytes = 0;
 	int ret = 0;
 
 	spin_lock(&space_info->lock);
 	while (ticket->bytes > 0 && ticket->error == 0) {
 		ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
 		if (ret) {
-			ret = -EINTR;
+			ticket->error = -EINTR;
 			break;
 		}
 		spin_unlock(&space_info->lock);
@@ -901,18 +900,7 @@ static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
 		finish_wait(&ticket->wait, &wait);
 		spin_lock(&space_info->lock);
 	}
-	if (!ret)
-		ret = ticket->error;
-	if (!list_empty(&ticket->list))
-		list_del_init(&ticket->list);
-	if (ticket->bytes && ticket->bytes < ticket->orig_bytes)
-		reclaim_bytes = ticket->orig_bytes - ticket->bytes;
 	spin_unlock(&space_info->lock);
-
-	if (reclaim_bytes)
-		btrfs_space_info_add_old_bytes(fs_info, space_info,
-					       reclaim_bytes);
-	return ret;
 }
 
 /**
@@ -1010,16 +998,18 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 		return ret;
 
 	if (flush == BTRFS_RESERVE_FLUSH_ALL)
-		return wait_reserve_ticket(fs_info, space_info, &ticket);
+		wait_reserve_ticket(fs_info, space_info, &ticket);
+	else
+		priority_reclaim_metadata_space(fs_info, space_info, &ticket);
 
-	ret = 0;
-	priority_reclaim_metadata_space(fs_info, space_info, &ticket);
 	spin_lock(&space_info->lock);
-	if (ticket.bytes) {
+	ret = ticket.error;
+	if (ticket.bytes || ticket.error) {
 		if (ticket.bytes < orig_bytes)
 			reclaim_bytes = orig_bytes - ticket.bytes;
 		list_del_init(&ticket.list);
-		ret = -ENOSPC;
+		if (!ret)
+			ret = -ENOSPC;
 	}
 	spin_unlock(&space_info->lock);