splice: fix problem with atime not being updated

A bug report on nfsd that states that since it was switched to use
splice instead of sendfile, the atime was no longer being updated
on the input file. do_generic_mapping_read() does this when accessing
the file, make splice do it for the direct splice handler.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

fs/splice.c

@@ -1031,7 +1031,11 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 			goto out_release;
 	}
 
+done:
 	pipe->nrbufs = pipe->curbuf = 0;
+	if (bytes > 0)
+		file_accessed(in);
+
 	return bytes;
 
 out_release:
@@ -1047,16 +1051,11 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 			buf->ops = NULL;
 		}
 	}
-	pipe->nrbufs = pipe->curbuf = 0;
-
-	/*
-	 * If we transferred some data, return the number of bytes:
-	 */
-	if (bytes > 0)
-		return bytes;
 
-	return ret;
+	if (!bytes)
+		bytes = ret;
 
+	goto done;
 }
 EXPORT_SYMBOL(splice_direct_to_actor);