fs/jffs2/compr.c

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