fuse: fix poll notify

Move fuse_copy_finish() to before calling fuse_notify_poll_wakeup().
This is not a big issue because fuse_notify_poll_wakeup() should be
atomic, but it's cleaner this way, and later uses of notification will
need to be able to finish the copying before performing some actions.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

fs/fuse/dev.c

@@ -826,16 +826,21 @@ static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
 			    struct fuse_copy_state *cs)
 {
 	struct fuse_notify_poll_wakeup_out outarg;
-	int err;
+	int err = -EINVAL;
 
 	if (size != sizeof(outarg))
-		return -EINVAL;
+		goto err;
 
 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
 	if (err)
-		return err;
+		goto err;
 
+	fuse_copy_finish(cs);
 	return fuse_notify_poll_wakeup(fc, &outarg);
+
+err:
+	fuse_copy_finish(cs);
+	return err;
 }
 
 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
@@ -846,6 +851,7 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
 		return fuse_notify_poll(fc, size, cs);
 
 	default:
+		fuse_copy_finish(cs);
 		return -EINVAL;
 	}
 }
@@ -924,7 +930,6 @@ static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
 	 */
 	if (!oh.unique) {
 		err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), &cs);
-		fuse_copy_finish(&cs);
 		return err ? err : nbytes;
 	}