+ dbg_io("LEB %d:%d, length %d", lnum, offs, len);
+ ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+ ubifs_assert(!(offs & 7) && offs < c->leb_size);
+ ubifs_assert(offs + len <= c->leb_size);
+
+ spin_lock(&wbuf->lock);
+ overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
+ if (!overlap) {
+ /* We may safely unlock the write-buffer and read the data */
+ spin_unlock(&wbuf->lock);
+ return ubi_read(c->ubi, lnum, buf, offs, len);
+ }
+
+ /* Don't read under wbuf */
+ rlen = wbuf->offs - offs;
+ if (rlen < 0)
+ rlen = 0;
+
+ /* Copy the rest from the write-buffer */
+ memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
+ spin_unlock(&wbuf->lock);
+
+ if (rlen > 0)
+ /* Read everything that goes before write-buffer */
+ return ubi_read(c->ubi, lnum, buf, offs, rlen);
+
+ return 0;
+}
+
+/**
+ * validate_data_node - validate data nodes for bulk-read.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing data node to validate
+ * @zbr: zbranch of data node to validate
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int validate_data_node(struct ubifs_info *c, void *buf,
+ struct ubifs_zbranch *zbr)
+{
+ union ubifs_key key1;
+ struct ubifs_ch *ch = buf;
+ int err, len;
+
+ if (ch->node_type != UBIFS_DATA_NODE) {
+ ubifs_err("bad node type (%d but expected %d)",
+ ch->node_type, UBIFS_DATA_NODE);
+ goto out_err;
+ }
+
+ err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
+ if (err) {
+ ubifs_err("expected node type %d", UBIFS_DATA_NODE);
+ goto out;
+ }
+
+ len = le32_to_cpu(ch->len);
+ if (len != zbr->len) {
+ ubifs_err("bad node length %d, expected %d", len, zbr->len);
+ goto out_err;
+ }
+
+ /* Make sure the key of the read node is correct */
+ key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
+ if (!keys_eq(c, &zbr->key, &key1)) {
+ ubifs_err("bad key in node at LEB %d:%d",
+ zbr->lnum, zbr->offs);
+ dbg_tnc("looked for key %s found node's key %s",
+ DBGKEY(&zbr->key), DBGKEY1(&key1));
+ goto out_err;
+ }