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linux/fs/jffs2/compr.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

470 lines
17 KiB
C
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/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright (C) 2001-2003 Red Hat, Inc.
* Created by Arjan van de Ven <arjanv@redhat.com>
*
* Copyright (C) 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
* University of Szeged, Hungary
*
* For licensing information, see the file 'LICENCE' in this directory.
*
* $Id: compr.c,v 1.42 2004/08/07 21:56:08 dwmw2 Exp $
*
*/
#include "compr.h"
static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
/* Available compressors are on this list */
static LIST_HEAD(jffs2_compressor_list);
/* Actual compression mode */
static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
/* Statistics for blocks stored without compression */
static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
/* jffs2_compress:
* @data: Pointer to uncompressed data
* @cdata: Pointer to returned pointer to buffer for compressed data
* @datalen: On entry, holds the amount of data available for compression.
* On exit, expected to hold the amount of data actually compressed.
* @cdatalen: On entry, holds the amount of space available for compressed
* data. On exit, expected to hold the actual size of the compressed
* data.
*
* Returns: Lower byte to be stored with data indicating compression type used.
* Zero is used to show that the data could not be compressed - the
* compressed version was actually larger than the original.
* Upper byte will be used later. (soon)
*
* If the cdata buffer isn't large enough to hold all the uncompressed data,
* jffs2_compress should compress as much as will fit, and should set
* *datalen accordingly to show the amount of data which were compressed.
*/
uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
unsigned char *data_in, unsigned char **cpage_out,
uint32_t *datalen, uint32_t *cdatalen)
{
int ret = JFFS2_COMPR_NONE;
int compr_ret;
struct jffs2_compressor *this, *best=NULL;
unsigned char *output_buf = NULL, *tmp_buf;
uint32_t orig_slen, orig_dlen;
uint32_t best_slen=0, best_dlen=0;
switch (jffs2_compression_mode) {
case JFFS2_COMPR_MODE_NONE:
break;
case JFFS2_COMPR_MODE_PRIORITY:
output_buf = kmalloc(*cdatalen,GFP_KERNEL);
if (!output_buf) {
printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
goto out;
}
orig_slen = *datalen;
orig_dlen = *cdatalen;
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
/* Skip decompress-only backwards-compatibility and disabled modules */
if ((!this->compress)||(this->disabled))
continue;
this->usecount++;
spin_unlock(&jffs2_compressor_list_lock);
*datalen = orig_slen;
*cdatalen = orig_dlen;
compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL);
spin_lock(&jffs2_compressor_list_lock);
this->usecount--;
if (!compr_ret) {
ret = this->compr;
this->stat_compr_blocks++;
this->stat_compr_orig_size += *datalen;
this->stat_compr_new_size += *cdatalen;
break;
}
}
spin_unlock(&jffs2_compressor_list_lock);
if (ret == JFFS2_COMPR_NONE) kfree(output_buf);
break;
case JFFS2_COMPR_MODE_SIZE:
orig_slen = *datalen;
orig_dlen = *cdatalen;
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
/* Skip decompress-only backwards-compatibility and disabled modules */
if ((!this->compress)||(this->disabled))
continue;
/* Allocating memory for output buffer if necessary */
if ((this->compr_buf_size<orig_dlen)&&(this->compr_buf)) {
spin_unlock(&jffs2_compressor_list_lock);
kfree(this->compr_buf);
spin_lock(&jffs2_compressor_list_lock);
this->compr_buf_size=0;
this->compr_buf=NULL;
}
if (!this->compr_buf) {
spin_unlock(&jffs2_compressor_list_lock);
tmp_buf = kmalloc(orig_dlen,GFP_KERNEL);
spin_lock(&jffs2_compressor_list_lock);
if (!tmp_buf) {
printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n",orig_dlen);
continue;
}
else {
this->compr_buf = tmp_buf;
this->compr_buf_size = orig_dlen;
}
}
this->usecount++;
spin_unlock(&jffs2_compressor_list_lock);
*datalen = orig_slen;
*cdatalen = orig_dlen;
compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL);
spin_lock(&jffs2_compressor_list_lock);
this->usecount--;
if (!compr_ret) {
if ((!best_dlen)||(best_dlen>*cdatalen)) {
best_dlen = *cdatalen;
best_slen = *datalen;
best = this;
}
}
}
if (best_dlen) {
*cdatalen = best_dlen;
*datalen = best_slen;
output_buf = best->compr_buf;
best->compr_buf = NULL;
best->compr_buf_size = 0;
best->stat_compr_blocks++;
best->stat_compr_orig_size += best_slen;
best->stat_compr_new_size += best_dlen;
ret = best->compr;
}
spin_unlock(&jffs2_compressor_list_lock);
break;
default:
printk(KERN_ERR "JFFS2: unknow compression mode.\n");
}
out:
if (ret == JFFS2_COMPR_NONE) {
*cpage_out = data_in;
*datalen = *cdatalen;
none_stat_compr_blocks++;
none_stat_compr_size += *datalen;
}
else {
*cpage_out = output_buf;
}
return ret;
}
int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
uint16_t comprtype, unsigned char *cdata_in,
unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
{
struct jffs2_compressor *this;
int ret;
/* Older code had a bug where it would write non-zero 'usercompr'
fields. Deal with it. */
if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
comprtype &= 0xff;
switch (comprtype & 0xff) {
case JFFS2_COMPR_NONE:
/* This should be special-cased elsewhere, but we might as well deal with it */
memcpy(data_out, cdata_in, datalen);
none_stat_decompr_blocks++;
break;
case JFFS2_COMPR_ZERO:
memset(data_out, 0, datalen);
break;
default:
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
if (comprtype == this->compr) {
this->usecount++;
spin_unlock(&jffs2_compressor_list_lock);
ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL);
spin_lock(&jffs2_compressor_list_lock);
if (ret) {
printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
}
else {
this->stat_decompr_blocks++;
}
this->usecount--;
spin_unlock(&jffs2_compressor_list_lock);
return ret;
}
}
printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
spin_unlock(&jffs2_compressor_list_lock);
return -EIO;
}
return 0;
}
int jffs2_register_compressor(struct jffs2_compressor *comp)
{
struct jffs2_compressor *this;
if (!comp->name) {
printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
return -1;
}
comp->compr_buf_size=0;
comp->compr_buf=NULL;
comp->usecount=0;
comp->stat_compr_orig_size=0;
comp->stat_compr_new_size=0;
comp->stat_compr_blocks=0;
comp->stat_decompr_blocks=0;
D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
if (this->priority < comp->priority) {
list_add(&comp->list, this->list.prev);
goto out;
}
}
list_add_tail(&comp->list, &jffs2_compressor_list);
out:
D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
})
spin_unlock(&jffs2_compressor_list_lock);
return 0;
}
int jffs2_unregister_compressor(struct jffs2_compressor *comp)
{
D2(struct jffs2_compressor *this;)
D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
spin_lock(&jffs2_compressor_list_lock);
if (comp->usecount) {
spin_unlock(&jffs2_compressor_list_lock);
printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
return -1;
}
list_del(&comp->list);
D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
})
spin_unlock(&jffs2_compressor_list_lock);
return 0;
}
#ifdef CONFIG_JFFS2_PROC
#define JFFS2_STAT_BUF_SIZE 16000
char *jffs2_list_compressors(void)
{
struct jffs2_compressor *this;
char *buf, *act_buf;
act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);
list_for_each_entry(this, &jffs2_compressor_list, list) {
act_buf += sprintf(act_buf, "%10s priority:%d ", this->name, this->priority);
if ((this->disabled)||(!this->compress))
act_buf += sprintf(act_buf,"disabled");
else
act_buf += sprintf(act_buf,"enabled");
act_buf += sprintf(act_buf,"\n");
}
return buf;
}
char *jffs2_stats(void)
{
struct jffs2_compressor *this;
char *buf, *act_buf;
act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);
act_buf += sprintf(act_buf,"JFFS2 compressor statistics:\n");
act_buf += sprintf(act_buf,"%10s ","none");
act_buf += sprintf(act_buf,"compr: %d blocks (%d) decompr: %d blocks\n", none_stat_compr_blocks,
none_stat_compr_size, none_stat_decompr_blocks);
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
act_buf += sprintf(act_buf,"%10s ",this->name);
if ((this->disabled)||(!this->compress))
act_buf += sprintf(act_buf,"- ");
else
act_buf += sprintf(act_buf,"+ ");
act_buf += sprintf(act_buf,"compr: %d blocks (%d/%d) decompr: %d blocks ", this->stat_compr_blocks,
this->stat_compr_new_size, this->stat_compr_orig_size,
this->stat_decompr_blocks);
act_buf += sprintf(act_buf,"\n");
}
spin_unlock(&jffs2_compressor_list_lock);
return buf;
}
char *jffs2_get_compression_mode_name(void)
{
switch (jffs2_compression_mode) {
case JFFS2_COMPR_MODE_NONE:
return "none";
case JFFS2_COMPR_MODE_PRIORITY:
return "priority";
case JFFS2_COMPR_MODE_SIZE:
return "size";
}
return "unkown";
}
int jffs2_set_compression_mode_name(const char *name)
{
if (!strcmp("none",name)) {
jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
return 0;
}
if (!strcmp("priority",name)) {
jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
return 0;
}
if (!strcmp("size",name)) {
jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
return 0;
}
return 1;
}
static int jffs2_compressor_Xable(const char *name, int disabled)
{
struct jffs2_compressor *this;
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
if (!strcmp(this->name, name)) {
this->disabled = disabled;
spin_unlock(&jffs2_compressor_list_lock);
return 0;
}
}
spin_unlock(&jffs2_compressor_list_lock);
printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);
return 1;
}
int jffs2_enable_compressor_name(const char *name)
{
return jffs2_compressor_Xable(name, 0);
}
int jffs2_disable_compressor_name(const char *name)
{
return jffs2_compressor_Xable(name, 1);
}
int jffs2_set_compressor_priority(const char *name, int priority)
{
struct jffs2_compressor *this,*comp;
spin_lock(&jffs2_compressor_list_lock);
list_for_each_entry(this, &jffs2_compressor_list, list) {
if (!strcmp(this->name, name)) {
this->priority = priority;
comp = this;
goto reinsert;
}
}
spin_unlock(&jffs2_compressor_list_lock);
printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);
return 1;
reinsert:
/* list is sorted in the order of priority, so if
we change it we have to reinsert it into the
good place */
list_del(&comp->list);
list_for_each_entry(this, &jffs2_compressor_list, list) {
if (this->priority < comp->priority) {
list_add(&comp->list, this->list.prev);
spin_unlock(&jffs2_compressor_list_lock);
return 0;
}
}
list_add_tail(&comp->list, &jffs2_compressor_list);
spin_unlock(&jffs2_compressor_list_lock);
return 0;
}
#endif
void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
{
if (orig != comprbuf)
kfree(comprbuf);
}
int jffs2_compressors_init(void)
{
/* Registering compressors */
#ifdef CONFIG_JFFS2_ZLIB
jffs2_zlib_init();
#endif
#ifdef CONFIG_JFFS2_RTIME
jffs2_rtime_init();
#endif
#ifdef CONFIG_JFFS2_RUBIN
jffs2_rubinmips_init();
jffs2_dynrubin_init();
#endif
#ifdef CONFIG_JFFS2_LZARI
jffs2_lzari_init();
#endif
#ifdef CONFIG_JFFS2_LZO
jffs2_lzo_init();
#endif
/* Setting default compression mode */
#ifdef CONFIG_JFFS2_CMODE_NONE
jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
#else
#ifdef CONFIG_JFFS2_CMODE_SIZE
jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
#else
D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
#endif
#endif
return 0;
}
int jffs2_compressors_exit(void)
{
/* Unregistering compressors */
#ifdef CONFIG_JFFS2_LZO
jffs2_lzo_exit();
#endif
#ifdef CONFIG_JFFS2_LZARI
jffs2_lzari_exit();
#endif
#ifdef CONFIG_JFFS2_RUBIN
jffs2_dynrubin_exit();
jffs2_rubinmips_exit();
#endif
#ifdef CONFIG_JFFS2_RTIME
jffs2_rtime_exit();
#endif
#ifdef CONFIG_JFFS2_ZLIB
jffs2_zlib_exit();
#endif
return 0;
}
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