fs/jffs2/compr.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2001-2007 Red Hat, Inc.
   5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
   6  * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
   7  *                  University of Szeged, Hungary
   8  *
   9  * Created by Arjan van de Ven <arjan@infradead.org>
  10  *
  11  * For licensing information, see the file 'LICENCE' in this directory.
  12  *
  13  */
  14
  15 #include "compr.h"
  16
  17 static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
  18
  19 /* Available compressors are on this list */
  20 static LIST_HEAD(jffs2_compressor_list);
  21
  22 /* Actual compression mode */
  23 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
  24
  25 /* Statistics for blocks stored without compression */
  26 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
  27
  28
  29 /*
  30  * Return 1 to use this compression
  31  */
  32 static int jffs2_is_best_compression(struct jffs2_compressor *this,
  33                 struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
  34 {
  35         switch (jffs2_compression_mode) {
  36         case JFFS2_COMPR_MODE_SIZE:
  37                 if (bestsize > size)
  38                         return 1;
  39                 return 0;
  40         case JFFS2_COMPR_MODE_FAVOURLZO:
  41                 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
  42                         return 1;
  43                 if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
  44                         return 1;
  45                 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
  46                         return 1;
  47                 if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
  48                         return 1;
  49
  50                 return 0;
  51         }
  52         /* Shouldn't happen */
  53         return 0;
  54 }
  55
  56 /* jffs2_compress:
  57  * @data_in: Pointer to uncompressed data
  58  * @cpage_out: Pointer to returned pointer to buffer for compressed data
  59  * @datalen: On entry, holds the amount of data available for compression.
  60  *      On exit, expected to hold the amount of data actually compressed.
  61  * @cdatalen: On entry, holds the amount of space available for compressed
  62  *      data. On exit, expected to hold the actual size of the compressed
  63  *      data.
  64  *
  65  * Returns: Lower byte to be stored with data indicating compression type used.
  66  * Zero is used to show that the data could not be compressed - the
  67  * compressed version was actually larger than the original.
  68  * Upper byte will be used later. (soon)
  69  *
  70  * If the cdata buffer isn't large enough to hold all the uncompressed data,
  71  * jffs2_compress should compress as much as will fit, and should set
  72  * *datalen accordingly to show the amount of data which were compressed.
  73  */
  74 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
  75                         unsigned char *data_in, unsigned char **cpage_out,
  76                         uint32_t *datalen, uint32_t *cdatalen)
  77 {
  78         int ret = JFFS2_COMPR_NONE;
  79         int mode, compr_ret;
  80         struct jffs2_compressor *this, *best=NULL;
  81         unsigned char *output_buf = NULL, *tmp_buf;
  82         uint32_t orig_slen, orig_dlen;
  83         uint32_t best_slen=0, best_dlen=0;
  84
  85         if (c->mount_opts.override_compr)
  86                 mode = c->mount_opts.compr;
  87         else
  88                 mode = jffs2_compression_mode;
  89
  90         switch (mode) {
  91         case JFFS2_COMPR_MODE_NONE:
  92                 break;
  93         case JFFS2_COMPR_MODE_PRIORITY:
  94                 output_buf = kmalloc(*cdatalen,GFP_KERNEL);
  95                 if (!output_buf) {
  96                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
  97                         goto out;
  98                 }
  99                 orig_slen = *datalen;
 100                 orig_dlen = *cdatalen;
 101                 spin_lock(&jffs2_compressor_list_lock);
 102                 list_for_each_entry(this, &jffs2_compressor_list, list) {
 103                         /* Skip decompress-only backwards-compatibility and disabled modules */
 104                         if ((!this->compress)||(this->disabled))
 105                                 continue;
 106
 107                         this->usecount++;
 108                         spin_unlock(&jffs2_compressor_list_lock);
 109                         *datalen  = orig_slen;
 110                         *cdatalen = orig_dlen;
 111                         compr_ret = this->compress(data_in, output_buf, datalen, cdatalen);
 112                         spin_lock(&jffs2_compressor_list_lock);
 113                         this->usecount--;
 114                         if (!compr_ret) {
 115                                 ret = this->compr;
 116                                 this->stat_compr_blocks++;
 117                                 this->stat_compr_orig_size += *datalen;
 118                                 this->stat_compr_new_size  += *cdatalen;
 119                                 break;
 120                         }
 121                 }
 122                 spin_unlock(&jffs2_compressor_list_lock);
 123                 if (ret == JFFS2_COMPR_NONE)
 124                         kfree(output_buf);
 125                 break;
 126         case JFFS2_COMPR_MODE_SIZE:
 127         case JFFS2_COMPR_MODE_FAVOURLZO:
 128                 orig_slen = *datalen;
 129                 orig_dlen = *cdatalen;
 130                 spin_lock(&jffs2_compressor_list_lock);
 131                 list_for_each_entry(this, &jffs2_compressor_list, list) {
 132                         /* Skip decompress-only backwards-compatibility and disabled modules */
 133                         if ((!this->compress)||(this->disabled))
 134                                 continue;
 135                         /* Allocating memory for output buffer if necessary */
 136                         if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
 137                                 spin_unlock(&jffs2_compressor_list_lock);
 138                                 kfree(this->compr_buf);
 139                                 spin_lock(&jffs2_compressor_list_lock);
 140                                 this->compr_buf_size=0;
 141                                 this->compr_buf=NULL;
 142                         }
 143                         if (!this->compr_buf) {
 144                                 spin_unlock(&jffs2_compressor_list_lock);
 145                                 tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
 146                                 spin_lock(&jffs2_compressor_list_lock);
 147                                 if (!tmp_buf) {
 148                                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n", orig_slen);
 149                                         continue;
 150                                 }
 151                                 else {
 152                                         this->compr_buf = tmp_buf;
 153                                         this->compr_buf_size = orig_slen;
 154                                 }
 155                         }
 156                         this->usecount++;
 157                         spin_unlock(&jffs2_compressor_list_lock);
 158                         *datalen  = orig_slen;
 159                         *cdatalen = orig_dlen;
 160                         compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
 161                         spin_lock(&jffs2_compressor_list_lock);
 162                         this->usecount--;
 163                         if (!compr_ret) {
 164                                 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
 165                                                 && (*cdatalen < *datalen)) {
 166                                         best_dlen = *cdatalen;
 167                                         best_slen = *datalen;
 168                                         best = this;
 169                                 }
 170                         }
 171                 }
 172                 if (best_dlen) {
 173                         *cdatalen = best_dlen;
 174                         *datalen  = best_slen;
 175                         output_buf = best->compr_buf;
 176                         best->compr_buf = NULL;
 177                         best->compr_buf_size = 0;
 178                         best->stat_compr_blocks++;
 179                         best->stat_compr_orig_size += best_slen;
 180                         best->stat_compr_new_size  += best_dlen;
 181                         ret = best->compr;
 182                 }
 183                 spin_unlock(&jffs2_compressor_list_lock);
 184                 break;
 185         default:
 186                 printk(KERN_ERR "JFFS2: unknown compression mode.\n");
 187         }
 188  out:
 189         if (ret == JFFS2_COMPR_NONE) {
 190                 *cpage_out = data_in;
 191                 *datalen = *cdatalen;
 192                 none_stat_compr_blocks++;
 193                 none_stat_compr_size += *datalen;
 194         }
 195         else {
 196                 *cpage_out = output_buf;
 197         }
 198         return ret;
 199 }
 200
 201 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
 202                      uint16_t comprtype, unsigned char *cdata_in,
 203                      unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
 204 {
 205         struct jffs2_compressor *this;
 206         int ret;
 207
 208         /* Older code had a bug where it would write non-zero 'usercompr'
 209            fields. Deal with it. */
 210         if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
 211                 comprtype &= 0xff;
 212
 213         switch (comprtype & 0xff) {
 214         case JFFS2_COMPR_NONE:
 215                 /* This should be special-cased elsewhere, but we might as well deal with it */
 216                 memcpy(data_out, cdata_in, datalen);
 217                 none_stat_decompr_blocks++;
 218                 break;
 219         case JFFS2_COMPR_ZERO:
 220                 memset(data_out, 0, datalen);
 221                 break;
 222         default:
 223                 spin_lock(&jffs2_compressor_list_lock);
 224                 list_for_each_entry(this, &jffs2_compressor_list, list) {
 225                         if (comprtype == this->compr) {
 226                                 this->usecount++;
 227                                 spin_unlock(&jffs2_compressor_list_lock);
 228                                 ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
 229                                 spin_lock(&jffs2_compressor_list_lock);
 230                                 if (ret) {
 231                                         printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
 232                                 }
 233                                 else {
 234                                         this->stat_decompr_blocks++;
 235                                 }
 236                                 this->usecount--;
 237                                 spin_unlock(&jffs2_compressor_list_lock);
 238                                 return ret;
 239                         }
 240                 }
 241                 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
 242                 spin_unlock(&jffs2_compressor_list_lock);
 243                 return -EIO;
 244         }
 245         return 0;
 246 }
 247
 248 int jffs2_register_compressor(struct jffs2_compressor *comp)
 249 {
 250         struct jffs2_compressor *this;
 251
 252         if (!comp->name) {
 253                 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
 254                 return -1;
 255         }
 256         comp->compr_buf_size=0;
 257         comp->compr_buf=NULL;
 258         comp->usecount=0;
 259         comp->stat_compr_orig_size=0;
 260         comp->stat_compr_new_size=0;
 261         comp->stat_compr_blocks=0;
 262         comp->stat_decompr_blocks=0;
 263         D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
 264
 265         spin_lock(&jffs2_compressor_list_lock);
 266
 267         list_for_each_entry(this, &jffs2_compressor_list, list) {
 268                 if (this->priority < comp->priority) {
 269                         list_add(&comp->list, this->list.prev);
 270                         goto out;
 271                 }
 272         }
 273         list_add_tail(&comp->list, &jffs2_compressor_list);
 274 out:
 275         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
 276                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
 277         })
 278
 279         spin_unlock(&jffs2_compressor_list_lock);
 280
 281         return 0;
 282 }
 283
 284 int jffs2_unregister_compressor(struct jffs2_compressor *comp)
 285 {
 286         D2(struct jffs2_compressor *this;)
 287
 288         D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
 289
 290         spin_lock(&jffs2_compressor_list_lock);
 291
 292         if (comp->usecount) {
 293                 spin_unlock(&jffs2_compressor_list_lock);
 294                 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
 295                 return -1;
 296         }
 297         list_del(&comp->list);
 298
 299         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
 300                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
 301         })
 302         spin_unlock(&jffs2_compressor_list_lock);
 303         return 0;
 304 }
 305
 306 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
 307 {
 308         if (orig != comprbuf)
 309                 kfree(comprbuf);
 310 }
 311
 312 int __init jffs2_compressors_init(void)
 313 {
 314 /* Registering compressors */
 315 #ifdef CONFIG_JFFS2_ZLIB
 316         jffs2_zlib_init();
 317 #endif
 318 #ifdef CONFIG_JFFS2_RTIME
 319         jffs2_rtime_init();
 320 #endif
 321 #ifdef CONFIG_JFFS2_RUBIN
 322         jffs2_rubinmips_init();
 323         jffs2_dynrubin_init();
 324 #endif
 325 #ifdef CONFIG_JFFS2_LZO
 326         jffs2_lzo_init();
 327 #endif
 328 /* Setting default compression mode */
 329 #ifdef CONFIG_JFFS2_CMODE_NONE
 330         jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
 331         D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
 332 #else
 333 #ifdef CONFIG_JFFS2_CMODE_SIZE
 334         jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
 335         D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
 336 #else
 337 #ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
 338         jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
 339         D1(printk(KERN_INFO "JFFS2: default compression mode: favourlzo\n");)
 340 #else
 341         D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
 342 #endif
 343 #endif
 344 #endif
 345         return 0;
 346 }
 347
 348 int jffs2_compressors_exit(void)
 349 {
 350 /* Unregistering compressors */
 351 #ifdef CONFIG_JFFS2_LZO
 352         jffs2_lzo_exit();
 353 #endif
 354 #ifdef CONFIG_JFFS2_RUBIN
 355         jffs2_dynrubin_exit();
 356         jffs2_rubinmips_exit();
 357 #endif
 358 #ifdef CONFIG_JFFS2_RTIME
 359         jffs2_rtime_exit();
 360 #endif
 361 #ifdef CONFIG_JFFS2_ZLIB
 362         jffs2_zlib_exit();
 363 #endif
 364         return 0;
 365 }