--- a/fs/jffs2/writev.c
+++ b/fs/jffs2/writev.c
@@ -16,9 +16,18 @@
 int jffs2_flash_direct_writev(struct jffs2_sb_info *c, const struct kvec *vecs,
 			      unsigned long count, loff_t to, size_t *retlen)
 {
+	int ret;
+
+	ret = mtd_writev(c->mtd, vecs, count, to, retlen);
+
 	if (!jffs2_is_writebuffered(c)) {
 		if (jffs2_sum_active()) {
 			int res;
+
+			if (ret ||
+			    *retlen != iov_length((struct iovec *) vecs, count))
+				return ret;
+
 			res = jffs2_sum_add_kvec(c, vecs, count, (uint32_t) to);
 			if (res) {
 				return res;
@@ -26,18 +35,22 @@
 		}
 	}
 
-	return mtd_writev(c->mtd, vecs, count, to, retlen);
+	return ret;
 }
 
 int jffs2_flash_direct_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
 			size_t *retlen, const u_char *buf)
 {
 	int ret;
+
 	ret = mtd_write(c->mtd, ofs, len, retlen, buf);
 
 	if (jffs2_sum_active()) {
 		struct kvec vecs[1];
 		int res;
+
+		if (ret || *retlen != len)
+			return ret;
 
 		vecs[0].iov_base = (unsigned char *) buf;
 		vecs[0].iov_len = len;
@@ -47,5 +60,6 @@
 			return res;
 		}
 	}
+
 	return ret;
 }