path: root/fs/jffs2/readinode.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: readinode.c,v 1.143 2005/11/07 11:14:41 gleixner Exp $
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/crc32.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include "nodelist.h"

/*
 * Put a new tmp_dnode_info into the temporaty RB-tree, keeping the list in
 * order of increasing version.
 */
static void jffs2_add_tn_to_tree(struct jffs2_tmp_dnode_info *tn, struct rb_root *list)
{
	struct rb_node **p = &list->rb_node;
	struct rb_node * parent = NULL;
	struct jffs2_tmp_dnode_info *this;

	while (*p) {
		parent = *p;
		this = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);

		/* There may actually be a collision here, but it doesn't
		   actually matter. As long as the two nodes with the same
		   version are together, it's all fine. */
		if (tn->version > this->version)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

	rb_link_node(&tn->rb, parent, p);
	rb_insert_color(&tn->rb, list);
}

static void jffs2_free_tmp_dnode_info_list(struct rb_root *list)
{
	struct rb_node *this;
	struct jffs2_tmp_dnode_info *tn;

	this = list->rb_node;

	/* Now at bottom of tree */
	while (this) {
		if (this->rb_left)
			this = this->rb_left;
		else if (this->rb_right)
			this = this->rb_right;
		else {
			tn = rb_entry(this, struct jffs2_tmp_dnode_info, rb);
			jffs2_free_full_dnode(tn->fn);
			jffs2_free_tmp_dnode_info(tn);

			this = rb_parent(this);
			if (!this)
				break;

			if (this->rb_left == &tn->rb)
				this->rb_left = NULL;
			else if (this->rb_right == &tn->rb)
				this->rb_right = NULL;
			else BUG();
		}
	}
	list->rb_node = NULL;
}

static void jffs2_free_full_dirent_list(struct jffs2_full_dirent *fd)
{
	struct jffs2_full_dirent *next;

	while (fd) {
		next = fd->next;
		jffs2_free_full_dirent(fd);
		fd = next;
	}
}

/* Returns first valid node after 'ref'. May return 'ref' */
static struct jffs2_raw_node_ref *jffs2_first_valid_node(struct jffs2_raw_node_ref *ref)
{
	while (ref && ref->next_in_ino) {
		if (!ref_obsolete(ref))
			return ref;
		dbg_noderef("node at 0x%08x is obsoleted. Ignoring.\n", ref_offset(ref));
		ref = ref->next_in_ino;
	}
	return NULL;
}

/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an directory entry node is found.
 *
 * Returns: 0 on succes;
 * 	    1 if the node should be marked obsolete;
 * 	    negative error code on failure.
 */
static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
				struct jffs2_raw_dirent *rd, size_t read, struct jffs2_full_dirent **fdp,
				uint32_t *latest_mctime, uint32_t *mctime_ver)
{
	struct jffs2_full_dirent *fd;
	uint32_t crc;

	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
	BUG_ON(ref_obsolete(ref));

	crc = crc32(0, rd, sizeof(*rd) - 8);
	if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
		JFFS2_NOTICE("header CRC failed on dirent node at %#08x: read %#08x, calculated %#08x\n",
			     ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
		return 1;
	}

	/* If we've never checked the CRCs on this node, check them now */
	if (ref_flags(ref) == REF_UNCHECKED) {
		struct jffs2_eraseblock *jeb;
		int len;

		/* Sanity check */
		if (unlikely(PAD((rd->nsize + sizeof(*rd))) != PAD(je32_to_cpu(rd->totlen)))) {
			JFFS2_ERROR("illegal nsize in node at %#08x: nsize %#02x, totlen %#04x\n",
				    ref_offset(ref), rd->nsize, je32_to_cpu(rd->totlen));
			return 1;
		}

		jeb = &c->blocks[ref->flash_offset / c->sector_size];
		len = ref_totlen(