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intrep.c
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/*
* JFFS -- Journaling Flash File System, Linux implementation.
*
* Copyright (C) 1999, 2000 Axis Communications, Inc.
*
* Created by Finn Hakansson <[email protected]>.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* $Id: intrep.c,v 1.102 2001/09/23 23:28:36 dwmw2 Exp $
*
* Ported to Linux 2.3.x and MTD:
* Copyright (C) 2000 Alexander Larsson ([email protected]), Cendio Systems AB
*
*/
/* This file contains the code for the internal structure of the
Journaling Flash File System, JFFS. */
/*
* Todo list:
*
* memcpy_to_flash() and memcpy_from_flash() functions.
*
* Implementation of hard links.
*
* Organize the source code in a better way. Against the VFS we could
* have jffs_ext.c, and against the block device jffs_int.c.
* A better file-internal organization too.
*
* A better checksum algorithm.
*
* Consider endianness stuff. ntohl() etc.
*
* Are we handling the atime, mtime, ctime members of the inode right?
*
* Remove some duplicated code. Take a look at jffs_write_node() and
* jffs_rewrite_data() for instance.
*
* Implement more meaning of the nlink member in various data structures.
* nlink could be used in conjunction with hard links for instance.
*
* Better memory management. Allocate data structures in larger chunks
* if possible.
*
* If too much meta data is stored, a garbage collect should be issued.
* We have experienced problems with too much meta data with for instance
* log files.
*
* Improve the calls to jffs_ioctl(). We would like to retrieve more
* information to be able to debug (or to supervise) JFFS during run-time.
*
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/jffs.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/pagemap.h>
#include <asm/semaphore.h>
#include <asm/byteorder.h>
#include <linux/smp_lock.h>
#include <linux/time.h>
#include <linux/ctype.h>
#include "intrep.h"
#include "jffs_fm.h"
long no_jffs_node = 0;
static long no_jffs_file = 0;
#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
long no_jffs_control = 0;
long no_jffs_raw_inode = 0;
long no_jffs_node_ref = 0;
long no_jffs_fm = 0;
long no_jffs_fmcontrol = 0;
long no_hash = 0;
long no_name = 0;
#endif
static int jffs_scan_flash(struct jffs_control *c);
static int jffs_update_file(struct jffs_file *f, struct jffs_node *node);
static int jffs_build_file(struct jffs_file *f);
static int jffs_free_file(struct jffs_file *f);
static int jffs_free_node_list(struct jffs_file *f);
static int jffs_garbage_collect_now(struct jffs_control *c);
static int jffs_insert_file_into_hash(struct jffs_file *f);
static int jffs_remove_redundant_nodes(struct jffs_file *f);
/* Is there enough space on the flash? */
static inline int JFFS_ENOUGH_SPACE(struct jffs_control *c, __u32 space)
{
struct jffs_fmcontrol *fmc = c->fmc;
while (1) {
if ((fmc->flash_size - (fmc->used_size + fmc->dirty_size))
>= fmc->min_free_size + space) {
return 1;
}
if (fmc->dirty_size < fmc->sector_size)
return 0;
if (jffs_garbage_collect_now(c)) {
D1(printk("JFFS_ENOUGH_SPACE: jffs_garbage_collect_now() failed.\n"));
return 0;
}
}
}
#if CONFIG_JFFS_FS_VERBOSE > 0
static __u8
flash_read_u8(struct mtd_info *mtd, loff_t from)
{
size_t retlen;
__u8 ret;
int res;
res = MTD_READ(mtd, from, 1, &retlen, &ret);
if (retlen != 1) {
printk("Didn't read a byte in flash_read_u8(). Returned %d\n", res);
return 0;
}
return ret;
}
static void
jffs_hexdump(struct mtd_info *mtd, loff_t pos, int size)
{
char line[16];
int j = 0;
while (size > 0) {
int i;
printk("%ld:", (long) pos);
for (j = 0; j < 16; j++) {
line[j] = flash_read_u8(mtd, pos++);
}
for (i = 0; i < j; i++) {
if (!(i & 1)) {
printk(" %.2x", line[i] & 0xff);
}
else {
printk("%.2x", line[i] & 0xff);
}
}
/* Print empty space */
for (; i < 16; i++) {
if (!(i & 1)) {
printk(" ");
}
else {
printk(" ");
}
}
printk(" ");
for (i = 0; i < j; i++) {
if (isgraph(line[i])) {
printk("%c", line[i]);
}
else {
printk(".");
}
}
printk("\n");
size -= 16;
}
}
/* Print the contents of a node. */
static void
jffs_print_node(struct jffs_node *n)
{
D(printk("jffs_node: 0x%p\n", n));
D(printk("{\n"));
D(printk(" 0x%08x, /* version */\n", n->version));
D(printk(" 0x%08x, /* data_offset */\n", n->data_offset));
D(printk(" 0x%08x, /* data_size */\n", n->data_size));
D(printk(" 0x%08x, /* removed_size */\n", n->removed_size));
D(printk(" 0x%08x, /* fm_offset */\n", n->fm_offset));
D(printk(" 0x%02x, /* name_size */\n", n->name_size));
D(printk(" 0x%p, /* fm, fm->offset: %u */\n",
n->fm, (n->fm ? n->fm->offset : 0)));
D(printk(" 0x%p, /* version_prev */\n", n->version_prev));
D(printk(" 0x%p, /* version_next */\n", n->version_next));
D(printk(" 0x%p, /* range_prev */\n", n->range_prev));
D(printk(" 0x%p, /* range_next */\n", n->range_next));
D(printk("}\n"));
}
#endif
/* Print the contents of a raw inode. */
static void
jffs_print_raw_inode(struct jffs_raw_inode *raw_inode)
{
D(printk("jffs_raw_inode: inode number: %u\n", raw_inode->ino));
D(printk("{\n"));
D(printk(" 0x%08x, /* magic */\n", raw_inode->magic));
D(printk(" 0x%08x, /* ino */\n", raw_inode->ino));
D(printk(" 0x%08x, /* pino */\n", raw_inode->pino));
D(printk(" 0x%08x, /* version */\n", raw_inode->version));
D(printk(" 0x%08x, /* mode */\n", raw_inode->mode));
D(printk(" 0x%04x, /* uid */\n", raw_inode->uid));
D(printk(" 0x%04x, /* gid */\n", raw_inode->gid));
D(printk(" 0x%08x, /* atime */\n", raw_inode->atime));
D(printk(" 0x%08x, /* mtime */\n", raw_inode->mtime));
D(printk(" 0x%08x, /* ctime */\n", raw_inode->ctime));
D(printk(" 0x%08x, /* offset */\n", raw_inode->offset));
D(printk(" 0x%08x, /* dsize */\n", raw_inode->dsize));
D(printk(" 0x%08x, /* rsize */\n", raw_inode->rsize));
D(printk(" 0x%02x, /* nsize */\n", raw_inode->nsize));
D(printk(" 0x%02x, /* nlink */\n", raw_inode->nlink));
D(printk(" 0x%02x, /* spare */\n",
raw_inode->spare));
D(printk(" %u, /* rename */\n",
raw_inode->rename));
D(printk(" %u, /* deleted */\n",
raw_inode->deleted));
D(printk(" 0x%02x, /* accurate */\n",
raw_inode->accurate));
D(printk(" 0x%08x, /* dchksum */\n", raw_inode->dchksum));
D(printk(" 0x%04x, /* nchksum */\n", raw_inode->nchksum));
D(printk(" 0x%04x, /* chksum */\n", raw_inode->chksum));
D(printk("}\n"));
}
#define flash_safe_acquire(arg)
#define flash_safe_release(arg)
static int
flash_safe_read(struct mtd_info *mtd, loff_t from,
u_char *buf, size_t count)
{
size_t retlen;
int res;
D3(printk(KERN_NOTICE "flash_safe_read(%p, %08x, %p, %08x)\n",
mtd, (unsigned int) from, buf, count));
res = MTD_READ(mtd, from, count, &retlen, buf);
if (retlen != count) {
panic("Didn't read all bytes in flash_safe_read(). Returned %d\n", res);
}
return res?res:retlen;
}
static __u32
flash_read_u32(struct mtd_info *mtd, loff_t from)
{
size_t retlen;
__u32 ret;
int res;
res = MTD_READ(mtd, from, 4, &retlen, (unsigned char *)&ret);
if (retlen != 4) {
printk("Didn't read all bytes in flash_read_u32(). Returned %d\n", res);
return 0;
}
return ret;
}
static int
flash_safe_write(struct mtd_info *mtd, loff_t to,
const u_char *buf, size_t count)
{
size_t retlen;
int res;
D3(printk(KERN_NOTICE "flash_safe_write(%p, %08x, %p, %08x)\n",
mtd, (unsigned int) to, buf, count));
res = MTD_WRITE(mtd, to, count, &retlen, buf);
if (retlen != count) {
printk("Didn't write all bytes in flash_safe_write(). Returned %d\n", res);
}
return res?res:retlen;
}
static int
flash_safe_writev(struct mtd_info *mtd, const struct kvec *vecs,
unsigned long iovec_cnt, loff_t to)
{
size_t retlen, retlen_a;
int i;
int res;
D3(printk(KERN_NOTICE "flash_safe_writev(%p, %08x, %p)\n",
mtd, (unsigned int) to, vecs));
if (mtd->writev) {
res = MTD_WRITEV(mtd, vecs, iovec_cnt, to, &retlen);
return res ? res : retlen;
}
/* Not implemented writev. Repeatedly use write - on the not so
unreasonable assumption that the mtd driver doesn't care how
many write cycles we use. */
res=0;
retlen=0;
for (i=0; !res && i<iovec_cnt; i++) {
res = MTD_WRITE(mtd, to, vecs[i].iov_len, &retlen_a, vecs[i].iov_base);
if (retlen_a != vecs[i].iov_len) {
printk("Didn't write all bytes in flash_safe_writev(). Returned %d\n", res);
if (i != iovec_cnt-1)
return -EIO;
}
/* If res is non-zero, retlen_a is undefined, but we don't
care because in that case it's not going to be
returned anyway.
*/
to += retlen_a;
retlen += retlen_a;
}
return res?res:retlen;
}
static int
flash_memset(struct mtd_info *mtd, loff_t to,
const u_char c, size_t size)
{
static unsigned char pattern[64];
int i;
/* fill up pattern */
for(i = 0; i < 64; i++)
pattern[i] = c;
/* write as many 64-byte chunks as we can */
while (size >= 64) {
flash_safe_write(mtd, to, pattern, 64);
size -= 64;
to += 64;
}
/* and the rest */
if(size)
flash_safe_write(mtd, to, pattern, size);
return size;
}
static void
intrep_erase_callback(struct erase_info *done)
{
wait_queue_head_t *wait_q;
wait_q = (wait_queue_head_t *)done->priv;
wake_up(wait_q);
}
static int
flash_erase_region(struct mtd_info *mtd, loff_t start,
size_t size)
{
struct erase_info *erase;
DECLARE_WAITQUEUE(wait, current);
wait_queue_head_t wait_q;
erase = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
if (!erase)
return -ENOMEM;
init_waitqueue_head(&wait_q);
erase->mtd = mtd;
erase->callback = intrep_erase_callback;
erase->addr = start;
erase->len = size;
erase->priv = (u_long)&wait_q;
/* FIXME: Use TASK_INTERRUPTIBLE and deal with being interrupted */
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&wait_q, &wait);
if (MTD_ERASE(mtd, erase) < 0) {
set_current_state(TASK_RUNNING);
remove_wait_queue(&wait_q, &wait);
kfree(erase);
printk(KERN_WARNING "flash: erase of region [0x%lx, 0x%lx] "
"totally failed\n", (long)start, (long)start + size);
return -1;
}
schedule(); /* Wait for flash to finish. */
remove_wait_queue(&wait_q, &wait);
kfree(erase);
return 0;
}
/* This routine calculates checksums in JFFS. */
static __u32
jffs_checksum(const void *data, int size)
{
__u32 sum = 0;
__u8 *ptr = (__u8 *)data;
while (size-- > 0) {
sum += *ptr++;
}
D3(printk(", result: 0x%08x\n", sum));
return sum;
}
static int
jffs_checksum_flash(struct mtd_info *mtd, loff_t start, int size, __u32 *result)
{
__u32 sum = 0;
loff_t ptr = start;
__u8 *read_buf;
int i, length;
/* Allocate read buffer */
read_buf = (__u8 *) kmalloc (sizeof(__u8) * 4096, GFP_KERNEL);
if (!read_buf) {
printk(KERN_NOTICE "kmalloc failed in jffs_checksum_flash()\n");
return -ENOMEM;
}
/* Loop until checksum done */
while (size) {
/* Get amount of data to read */
if (size < 4096)
length = size;
else
length = 4096;
/* Perform flash read */
D3(printk(KERN_NOTICE "jffs_checksum_flash\n"));
flash_safe_read(mtd, ptr, &read_buf[0], length);
/* Compute checksum */
for (i=0; i < length ; i++)
sum += read_buf[i];
/* Update pointer and size */
size -= length;
ptr += length;
}
/* Free read buffer */
kfree (read_buf);
/* Return result */
D3(printk("checksum result: 0x%08x\n", sum));
*result = sum;
return 0;
}
static __inline__ void jffs_fm_write_lock(struct jffs_fmcontrol *fmc)
{
// down(&fmc->wlock);
}
static __inline__ void jffs_fm_write_unlock(struct jffs_fmcontrol *fmc)
{
// up(&fmc->wlock);
}
/* Create and initialize a new struct jffs_file. */
static struct jffs_file *
jffs_create_file(struct jffs_control *c,
const struct jffs_raw_inode *raw_inode)
{
struct jffs_file *f;
if (!(f = (struct jffs_file *)kmalloc(sizeof(struct jffs_file),
GFP_KERNEL))) {
D(printk("jffs_create_file(): Failed!\n"));
return NULL;
}
no_jffs_file++;
memset(f, 0, sizeof(struct jffs_file));
f->ino = raw_inode->ino;
f->pino = raw_inode->pino;
f->nlink = raw_inode->nlink;
f->deleted = raw_inode->deleted;
f->c = c;
return f;
}
/* Build a control block for the file system. */
static struct jffs_control *
jffs_create_control(struct super_block *sb)
{
struct jffs_control *c;
register int s = sizeof(struct jffs_control);
int i;
D(char *t = 0);
D2(printk("jffs_create_control()\n"));
if (!(c = (struct jffs_control *)kmalloc(s, GFP_KERNEL))) {
goto fail_control;
}
DJM(no_jffs_control++);
c->root = NULL;
c->gc_task = NULL;
c->hash_len = JFFS_HASH_SIZE;
s = sizeof(struct list_head) * c->hash_len;
if (!(c->hash = (struct list_head *)kmalloc(s, GFP_KERNEL))) {
goto fail_hash;
}
DJM(no_hash++);
for (i = 0; i < c->hash_len; i++)
INIT_LIST_HEAD(&c->hash[i]);
if (!(c->fmc = jffs_build_begin(c, MINOR(sb->s_dev)))) {
goto fail_fminit;
}
c->next_ino = JFFS_MIN_INO + 1;
c->delete_list = (struct jffs_delete_list *) 0;
return c;
fail_fminit:
D(t = "c->fmc");
fail_hash:
kfree(c);
DJM(no_jffs_control--);
D(t = t ? t : "c->hash");
fail_control:
D(t = t ? t : "control");
D(printk("jffs_create_control(): Allocation failed: (%s)\n", t));
return (struct jffs_control *)0;
}
/* Clean up all data structures associated with the file system. */
void
jffs_cleanup_control(struct jffs_control *c)
{
D2(printk("jffs_cleanup_control()\n"));
if (!c) {
D(printk("jffs_cleanup_control(): c == NULL !!!\n"));
return;
}
while (c->delete_list) {
struct jffs_delete_list *delete_list_element;
delete_list_element = c->delete_list;
c->delete_list = c->delete_list->next;
kfree(delete_list_element);
}
/* Free all files and nodes. */
if (c->hash) {
jffs_foreach_file(c, jffs_free_node_list);
jffs_foreach_file(c, jffs_free_file);
kfree(c->hash);
DJM(no_hash--);
}
jffs_cleanup_fmcontrol(c->fmc);
kfree(c);
DJM(no_jffs_control--);
D3(printk("jffs_cleanup_control(): Leaving...\n"));
}
/* This function adds a virtual root node to the in-RAM representation.
Called by jffs_build_fs(). */
static int
jffs_add_virtual_root(struct jffs_control *c)
{
struct jffs_file *root;
struct jffs_node *node;
D2(printk("jffs_add_virtual_root(): "
"Creating a virtual root directory.\n"));
if (!(root = (struct jffs_file *)kmalloc(sizeof(struct jffs_file),
GFP_KERNEL))) {
return -ENOMEM;
}
no_jffs_file++;
if (!(node = jffs_alloc_node())) {
kfree(root);
no_jffs_file--;
return -ENOMEM;
}
DJM(no_jffs_node++);
memset(node, 0, sizeof(struct jffs_node));
node->ino = JFFS_MIN_INO;
memset(root, 0, sizeof(struct jffs_file));
root->ino = JFFS_MIN_INO;
root->mode = S_IFDIR | S_IRWXU | S_IRGRP
| S_IXGRP | S_IROTH | S_IXOTH;
root->atime = root->mtime = root->ctime = get_seconds();
root->nlink = 1;
root->c = c;
root->version_head = root->version_tail = node;
jffs_insert_file_into_hash(root);
return 0;
}
/* This is where the file system is built and initialized. */
int
jffs_build_fs(struct super_block *sb)
{
struct jffs_control *c;
int err = 0;
D2(printk("jffs_build_fs()\n"));
if (!(c = jffs_create_control(sb))) {
return -ENOMEM;
}
c->building_fs = 1;
c->sb = sb;
if ((err = jffs_scan_flash(c)) < 0) {
if(err == -EAGAIN){
/* scan_flash() wants us to try once more. A flipping
bits sector was detect in the middle of the scan flash.
Clean up old allocated memory before going in.
*/
D1(printk("jffs_build_fs: Cleaning up all control structures,"
" reallocating them and trying mount again.\n"));
jffs_cleanup_control(c);
if (!(c = jffs_create_control(sb))) {
return -ENOMEM;
}
c->building_fs = 1;
c->sb = sb;
if ((err = jffs_scan_flash(c)) < 0) {
goto jffs_build_fs_fail;
}
}else{
goto jffs_build_fs_fail;
}
}
/* Add a virtual root node if no one exists. */
if (!jffs_find_file(c, JFFS_MIN_INO)) {
if ((err = jffs_add_virtual_root(c)) < 0) {
goto jffs_build_fs_fail;
}
}
while (c->delete_list) {
struct jffs_file *f;
struct jffs_delete_list *delete_list_element;
if ((f = jffs_find_file(c, c->delete_list->ino))) {
f->deleted = 1;
}
delete_list_element = c->delete_list;
c->delete_list = c->delete_list->next;
kfree(delete_list_element);
}
/* Remove deleted nodes. */
if ((err = jffs_foreach_file(c, jffs_possibly_delete_file)) < 0) {
printk(KERN_ERR "JFFS: Failed to remove deleted nodes.\n");
goto jffs_build_fs_fail;
}
/* Remove redundant nodes. (We are not interested in the
return value in this case.) */
jffs_foreach_file(c, jffs_remove_redundant_nodes);
/* Try to build a tree from all the nodes. */
if ((err = jffs_foreach_file(c, jffs_insert_file_into_tree)) < 0) {
printk("JFFS: Failed to build tree.\n");
goto jffs_build_fs_fail;
}
/* Compute the sizes of all files in the filesystem. Adjust if
necessary. */
if ((err = jffs_foreach_file(c, jffs_build_file)) < 0) {
printk("JFFS: Failed to build file system.\n");
goto jffs_build_fs_fail;
}
sb->s_fs_info = (void *)c;
c->building_fs = 0;
D1(jffs_print_hash_table(c));
D1(jffs_print_tree(c->root, 0));
return 0;
jffs_build_fs_fail:
jffs_cleanup_control(c);
return err;
} /* jffs_build_fs() */
/*
This checks for sectors that were being erased in their previous
lifetimes and for some reason or the other (power fail etc.),
the erase cycles never completed.
As the flash array would have reverted back to read status,
these sectors are detected by the symptom of the "flipping bits",
i.e. bits being read back differently from the same location in
flash if read multiple times.
The only solution to this is to re-erase the entire
sector.
Unfortunately detecting "flipping bits" is not a simple exercise
as a bit may be read back at 1 or 0 depending on the alignment
of the stars in the universe.
The level of confidence is in direct proportion to the number of
scans done. By power fail testing I (Vipin) have been able to
proove that reading twice is not enough.
Maybe 4 times? Change NUM_REREADS to a higher number if you want
a (even) higher degree of confidence in your mount process.
A higher number would of course slow down your mount.
*/
static int check_partly_erased_sectors(struct jffs_fmcontrol *fmc){
#define NUM_REREADS 4 /* see note above */
#define READ_AHEAD_BYTES 4096 /* must be a multiple of 4,
usually set to kernel page size */
__u8 *read_buf1;
__u8 *read_buf2;
int err = 0;
int retlen;
int i;
int cnt;
__u32 offset;
loff_t pos = 0;
loff_t end = fmc->flash_size;
/* Allocate read buffers */
read_buf1 = (__u8 *) kmalloc (sizeof(__u8) * READ_AHEAD_BYTES, GFP_KERNEL);
if (!read_buf1)
return -ENOMEM;
read_buf2 = (__u8 *) kmalloc (sizeof(__u8) * READ_AHEAD_BYTES, GFP_KERNEL);
if (!read_buf2) {
kfree(read_buf1);
return -ENOMEM;
}
CHECK_NEXT:
while(pos < end){
D1(printk("check_partly_erased_sector():checking sector which contains"
" offset 0x%x for flipping bits..\n", (__u32)pos));
retlen = flash_safe_read(fmc->mtd, pos,
&read_buf1[0], READ_AHEAD_BYTES);
retlen &= ~3;
for(cnt = 0; cnt < NUM_REREADS; cnt++){
(void)flash_safe_read(fmc->mtd, pos,
&read_buf2[0], READ_AHEAD_BYTES);
for (i=0 ; i < retlen ; i+=4) {
/* buffers MUST match, double word for word! */
if(*((__u32 *) &read_buf1[i]) !=
*((__u32 *) &read_buf2[i])
){
/* flipping bits detected, time to erase sector */
/* This will help us log some statistics etc. */
D1(printk("Flipping bits detected in re-read round:%i of %i\n",
cnt, NUM_REREADS));
D1(printk("check_partly_erased_sectors:flipping bits detected"
" @offset:0x%x(0x%x!=0x%x)\n",
(__u32)pos+i, *((__u32 *) &read_buf1[i]),
*((__u32 *) &read_buf2[i])));
/* calculate start of present sector */
offset = (((__u32)pos+i)/(__u32)fmc->sector_size) * (__u32)fmc->sector_size;
D1(printk("check_partly_erased_sector():erasing sector starting 0x%x.\n",
offset));
if (flash_erase_region(fmc->mtd,
offset, fmc->sector_size) < 0) {
printk(KERN_ERR "JFFS: Erase of flash failed. "
"offset = %u, erase_size = %d\n",
offset , fmc->sector_size);
err = -EIO;
goto returnBack;
}else{
D1(printk("JFFS: Erase of flash sector @0x%x successful.\n",
offset));
/* skip ahead to the next sector */
pos = (((__u32)pos+i)/(__u32)fmc->sector_size) * (__u32)fmc->sector_size;
pos += fmc->sector_size;
goto CHECK_NEXT;
}
}
}
}
pos += READ_AHEAD_BYTES;
}
returnBack:
kfree(read_buf1);
kfree(read_buf2);
D2(printk("check_partly_erased_sector():Done checking all sectors till offset 0x%x for flipping bits.\n",
(__u32)pos));
return err;
}/* end check_partly_erased_sectors() */
/* Scan the whole flash memory in order to find all nodes in the
file systems. */
static int
jffs_scan_flash(struct jffs_control *c)
{
char name[JFFS_MAX_NAME_LEN + 2];
struct jffs_raw_inode raw_inode;
struct jffs_node *node = NULL;
struct jffs_fmcontrol *fmc = c->fmc;
__u32 checksum;
__u8 tmp_accurate;
__u16 tmp_chksum;
__u32 deleted_file;
loff_t pos = 0;
loff_t start;
loff_t test_start;
loff_t end = fmc->flash_size;
__u8 *read_buf;
int i, len, retlen;
__u32 offset;
__u32 free_chunk_size1;
__u32 free_chunk_size2;
#define NUMFREEALLOWED 2 /* 2 chunks of at least erase size space allowed */
int num_free_space = 0; /* Flag err if more than TWO
free blocks found. This is NOT allowed
by the current jffs design.
*/
int num_free_spc_not_accp = 0; /* For debugging purposed keep count
of how much free space was rejected and
marked dirty
*/
D1(printk("jffs_scan_flash(): start pos = 0x%lx, end = 0x%lx\n",
(long)pos, (long)end));
flash_safe_acquire(fmc->mtd);
/*
check and make sure that any sector does not suffer
from the "partly erased, bit flipping syndrome" (TM Vipin :)
If so, offending sectors will be erased.
*/
if(check_partly_erased_sectors(fmc) < 0){
flash_safe_release(fmc->mtd);
return -EIO; /* bad, bad, bad error. Cannot continue.*/
}
/* Allocate read buffer */
read_buf = (__u8 *) kmalloc (sizeof(__u8) * 4096, GFP_KERNEL);
if (!read_buf) {
flash_safe_release(fmc->mtd);
return -ENOMEM;
}
/* Start the scan. */
while (pos < end) {
deleted_file = 0;
/* Remember the position from where we started this scan. */
start = pos;
switch (flash_read_u32(fmc->mtd, pos)) {
case JFFS_EMPTY_BITMASK:
/* We have found 0xffffffff at this position. We have to
scan the rest of the flash till the end or till
something else than 0xffffffff is found.
Keep going till we do not find JFFS_EMPTY_BITMASK
anymore */
D1(printk("jffs_scan_flash(): 0xffffffff at pos 0x%lx.\n",
(long)pos));
while(pos < end){
len = end - pos < 4096 ? end - pos : 4096;
retlen = flash_safe_read(fmc->mtd, pos,
&read_buf[0], len);
retlen &= ~3;
for (i=0 ; i < retlen ; i+=4, pos += 4) {
if(*((__u32 *) &read_buf[i]) !=
JFFS_EMPTY_BITMASK)
break;
}
if (i == retlen)
continue;
else
break;
}
D1(printk("jffs_scan_flash():0xffffffff ended at pos 0x%lx.\n",
(long)pos));
/* If some free space ends in the middle of a sector,
treat it as dirty rather than clean.
This is to handle the case where one thread
allocated space for a node, but didn't get to
actually _write_ it before power was lost, leaving
a gap in the log. Shifting all node writes into
a single kernel thread will fix the original problem.
*/
if ((__u32) pos % fmc->sector_size) {
/* If there was free space in previous
sectors, don't mark that dirty too -
only from the beginning of this sector
(or from start)
*/
test_start = pos & ~(fmc->sector_size-1); /* end of last sector */
if (start < test_start) {
/* free space started in the previous sector! */
if((num_free_space < NUMFREEALLOWED) &&
((unsigned int)(test_start - start) >= fmc->sector_size)){
/*
Count it in if we are still under NUMFREEALLOWED *and* it is
at least 1 erase sector in length. This will keep us from
picking any little ole' space as "free".
*/
D1(printk("Reducing end of free space to 0x%x from 0x%x\n",
(unsigned int)test_start, (unsigned int)pos));
D1(printk("Free space accepted: Starting 0x%x for 0x%x bytes\n",
(unsigned int) start,
(unsigned int)(test_start - start)));
/* below, space from "start" to "pos" will be marked dirty. */
start = test_start;
/* Being in here means that we have found at least an entire
erase sector size of free space ending on a sector boundary.
Keep track of free spaces accepted.
*/
num_free_space++;
}else{
num_free_spc_not_accp++;
D1(printk("Free space (#%i) found but *Not* accepted: Starting"
" 0x%x for 0x%x bytes\n",
num_free_spc_not_accp, (unsigned int)start,
(unsigned int)((unsigned int)(pos & ~(fmc->sector_size-1)) - (unsigned int)start)));
}
}
if((((__u32)(pos - start)) != 0)){
D1(printk("Dirty space: Starting 0x%x for 0x%x bytes\n",
(unsigned int) start, (unsigned int) (pos - start)));
jffs_fmalloced(fmc, (__u32) start,
(__u32) (pos - start), NULL);
}else{
/* "Flipping bits" detected. This means that our scan for them
did not catch this offset. See check_partly_erased_sectors() for
more info.
*/
D1(printk("jffs_scan_flash():wants to allocate dirty flash "
"space for 0 bytes.\n"));
D1(printk("jffs_scan_flash(): Flipping bits! We will free "
"all allocated memory, erase this sector and remount\n"));