+ if (jffs2_is_writebuffered(c) && csize != 0) {
+ /* At this point we are supposed to check the data CRC
+ * of our unchecked node. But thus far, we do not
+ * know whether the node is valid or obsolete. To
+ * figure this out, we need to walk all the nodes of
+ * the inode and build the inode fragtree. We don't
+ * want to spend time checking data of nodes which may
+ * later be found to be obsolete. So we put off the full
+ * data CRC checking until we have read all the inode
+ * nodes and have started building the fragtree.
+ *
+ * The fragtree is being built starting with nodes
+ * having the highest version number, so we'll be able
+ * to detect whether a node is valid (i.e., it is not
+ * overlapped by a node with higher version) or not.
+ * And we'll be able to check only those nodes, which
+ * are not obsolete.
+ *
+ * Of course, this optimization only makes sense in case
+ * of NAND flashes (or other flashes whith
+ * !jffs2_can_mark_obsolete()), since on NOR flashes
+ * nodes are marked obsolete physically.
+ *
+ * Since NAND flashes (or other flashes with
+ * jffs2_is_writebuffered(c)) are anyway read by
+ * fractions of c->wbuf_pagesize, and we have just read
+ * the node header, it is likely that the starting part
+ * of the node data is also read when we read the
+ * header. So we don't mind to check the CRC of the
+ * starting part of the data of the node now, and check
+ * the second part later (in jffs2_check_node_data()).
+ * Of course, we will not need to re-read and re-check
+ * the NAND page which we have just read. This is why we
+ * read the whole NAND page at jffs2_get_inode_nodes(),
+ * while we needed only the node header.
+ */
+ unsigned char *buf;
+
+ /* 'buf' will point to the start of data */
+ buf = (unsigned char *)rd + sizeof(*rd);
+ /* len will be the read data length */
+ len = min_t(uint32_t, rdlen - sizeof(*rd), csize);
+ tn->partial_crc = crc32(0, buf, len);
+
+ dbg_readinode("Calculates CRC (%#08x) for %d bytes, csize %d\n", tn->partial_crc, len, csize);
+
+ /* If we actually calculated the whole data CRC
+ * and it is wrong, drop the node. */
+ if (len >= csize && unlikely(tn->partial_crc != je32_to_cpu(rd->data_crc))) {
+ JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
+ ref_offset(ref), tn->partial_crc, je32_to_cpu(rd->data_crc));
+ goto free_out;
+ }
+
+ } else if (csize == 0) {
+ /*
+ * We checked the header CRC. If the node has no data, adjust
+ * the space accounting now. For other nodes this will be done
+ * later either when the node is marked obsolete or when its
+ * data is checked.
+ */
+ struct jffs2_eraseblock *jeb;
+
+ dbg_readinode("the node has no data.\n");
+ jeb = &c->blocks[ref->flash_offset / c->sector_size];
+ len = ref_totlen(c, jeb, ref);
+
+ spin_lock(&c->erase_completion_lock);
+ jeb->used_size += len;
+ jeb->unchecked_size -= len;
+ c->used_size += len;
+ c->unchecked_size -= len;
+ ref->flash_offset = ref_offset(ref) | REF_NORMAL;
+ spin_unlock(&c->erase_completion_lock);