path: root/fs/jffs2/scan.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define DEFAULT_EMPTY_SCAN_SIZE 256

#define noisy_printk(noise, fmt, ...)					\
do {									\
	if (*(noise)) {							\
		pr_notice(fmt, ##__VA_ARGS__);				\
		(*(noise))--;						\
		if (!(*(noise)))					\
			pr_notice("Further such events for this erase block will not be printed\n"); \
	}								\
} while (0)

static uint32_t pseudo_random;

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);

/* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
 * Returning an error will abort the mount - bad checksums etc. should just mark the space
 * as dirty.
 */
static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);

static inline int min_free(struct jffs2_sb_info *c)
{
	uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
		return c->wbuf_pagesize;
#endif
	return min;

}

static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
	if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
		return sector_size;
	else
		return DEFAULT_EMPTY_SCAN_SIZE;
}

static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	int ret;

	if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
		return ret;
	if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
		return ret;
	/* Turned wasted size into dirty, since we apparently 
	   think it's recoverable now. */
	jeb->dirty_size += jeb->wasted_size;
	c->dirty_size += jeb->wasted_size;
	c->wasted_size -= jeb->wasted_size;
	jeb->wasted_size = 0;
	if (VERYDIRTY(c, jeb->dirty_size)) {
		list_add(&jeb->list, &c->very_dirty_list);
	} else {
		list_add(&jeb->list, &c->dirty_list);
	}
	return 0;
}

int jffs2_scan_medium(struct jffs2_sb_info *c)
{
	int i, ret;
	uint32_t empty_blocks = 0, bad_blocks = 0;
	unsigned char *flashbuf = NULL;
	uint32_t buf_size = 0;
	struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
#ifndef __ECOS
	size_t pointlen, try_size;

	ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
			(void **)&