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 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 switch (jffs2_compression_mode) { 86 case JFFS2_COMPR_MODE_NONE: 87 break; 88 case JFFS2_COMPR_MODE_PRIORITY: 89 output_buf = kmalloc(*cdatalen,GFP_KERNEL); 90 if (!output_buf) { 91 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n"); 92 goto out; 93 } 94 orig_slen = *datalen; 95 orig_dlen = *cdatalen; 96 spin_lock(&jffs2_compressor_list_lock); 97 list_for_each_entry(this, &jffs2_compressor_list, list) { 98 /* Skip decompress-only backwards-compatibility and disabled modules */ 99 if ((!this->compress)||(this->disabled)) 100 continue; 101 102 this->usecount++; 103 spin_unlock(&jffs2_compressor_list_lock); 104 *datalen = orig_slen; 105 *cdatalen = orig_dlen; 106 compr_ret = this->compress(data_in, output_buf, datalen, cdatalen); 107 spin_lock(&jffs2_compressor_list_lock); 108 this->usecount--; 109 if (!compr_ret) { 110 ret = this->compr; 111 this->stat_compr_blocks++; 112 this->stat_compr_orig_size += *datalen; 113 this->stat_compr_new_size += *cdatalen; 114 break; 115 } 116 } 117 spin_unlock(&jffs2_compressor_list_lock); 118 if (ret == JFFS2_COMPR_NONE) 119 kfree(output_buf); 120 break; 121 case JFFS2_COMPR_MODE_SIZE: 122 case JFFS2_COMPR_MODE_FAVOURLZO: 123 orig_slen = *datalen; 124 orig_dlen = *cdatalen; 125 spin_lock(&jffs2_compressor_list_lock); 126 list_for_each_entry(this, &jffs2_compressor_list, list) { 127 /* Skip decompress-only backwards-compatibility and disabled modules */ 128 if ((!this->compress)||(this->disabled)) 129 continue; 130 /* Allocating memory for output buffer if necessary */ 131 if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) { 132 spin_unlock(&jffs2_compressor_list_lock); 133 kfree(this->compr_buf); 134 spin_lock(&jffs2_compressor_list_lock); 135 this->compr_buf_size=0; 136 this->compr_buf=NULL; 137 } 138 if (!this->compr_buf) { 139 spin_unlock(&jffs2_compressor_list_lock); 140 tmp_buf = kmalloc(orig_slen, GFP_KERNEL); 141 spin_lock(&jffs2_compressor_list_lock); 142 if (!tmp_buf) { 143 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n", orig_slen); 144 continue; 145 } 146 else { 147 this->compr_buf = tmp_buf; 148 this->compr_buf_size = orig_slen; 149 } 150 } 151 this->usecount++; 152 spin_unlock(&jffs2_compressor_list_lock); 153 *datalen = orig_slen; 154 *cdatalen = orig_dlen; 155 compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen); 156 spin_lock(&jffs2_compressor_list_lock); 157 this->usecount--; 158 if (!compr_ret) { 159 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen)) 160 && (*cdatalen < *datalen)) { 161 best_dlen = *cdatalen; 162 best_slen = *datalen; 163 best = this; 164 } 165 } 166 } 167 if (best_dlen) { 168 *cdatalen = best_dlen; 169 *datalen = best_slen; 170 output_buf = best->compr_buf; 171 best->compr_buf = NULL; 172 best->compr_buf_size = 0; 173 best->stat_compr_blocks++; 174 best->stat_compr_orig_size += best_slen; 175 best->stat_compr_new_size += best_dlen; 176 ret = best->compr; 177 } 178 spin_unlock(&jffs2_compressor_list_lock); 179 break; 180 default: 181 printk(KERN_ERR "JFFS2: unknown compression mode.\n"); 182 } 183 out: 184 if (ret == JFFS2_COMPR_NONE) { 185 *cpage_out = data_in; 186 *datalen = *cdatalen; 187 none_stat_compr_blocks++; 188 none_stat_compr_size += *datalen; 189 } 190 else { 191 *cpage_out = output_buf; 192 } 193 return ret; 194 } 195 196 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 197 uint16_t comprtype, unsigned char *cdata_in, 198 unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) 199 { 200 struct jffs2_compressor *this; 201 int ret; 202 203 /* Older code had a bug where it would write non-zero 'usercompr' 204 fields. Deal with it. */ 205 if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) 206 comprtype &= 0xff; 207 208 switch (comprtype & 0xff) { 209 case JFFS2_COMPR_NONE: 210 /* This should be special-cased elsewhere, but we might as well deal with it */ 211 memcpy(data_out, cdata_in, datalen); 212 none_stat_decompr_blocks++; 213 break; 214 case JFFS2_COMPR_ZERO: 215 memset(data_out, 0, datalen); 216 break; 217 default: 218 spin_lock(&jffs2_compressor_list_lock); 219 list_for_each_entry(this, &jffs2_compressor_list, list) { 220 if (comprtype == this->compr) { 221 this->usecount++; 222 spin_unlock(&jffs2_compressor_list_lock); 223 ret = this->decompress(cdata_in, data_out, cdatalen, datalen); 224 spin_lock(&jffs2_compressor_list_lock); 225 if (ret) { 226 printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret); 227 } 228 else { 229 this->stat_decompr_blocks++; 230 } 231 this->usecount--; 232 spin_unlock(&jffs2_compressor_list_lock); 233 return ret; 234 } 235 } 236 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype); 237 spin_unlock(&jffs2_compressor_list_lock); 238 return -EIO; 239 } 240 return 0; 241 } 242 243 int jffs2_register_compressor(struct jffs2_compressor *comp) 244 { 245 struct jffs2_compressor *this; 246 247 if (!comp->name) { 248 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n"); 249 return -1; 250 } 251 comp->compr_buf_size=0; 252 comp->compr_buf=NULL; 253 comp->usecount=0; 254 comp->stat_compr_orig_size=0; 255 comp->stat_compr_new_size=0; 256 comp->stat_compr_blocks=0; 257 comp->stat_decompr_blocks=0; 258 D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name)); 259 260 spin_lock(&jffs2_compressor_list_lock); 261 262 list_for_each_entry(this, &jffs2_compressor_list, list) { 263 if (this->priority < comp->priority) { 264 list_add(&comp->list, this->list.prev); 265 goto out; 266 } 267 } 268 list_add_tail(&comp->list, &jffs2_compressor_list); 269 out: 270 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 271 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 272 }) 273 274 spin_unlock(&jffs2_compressor_list_lock); 275 276 return 0; 277 } 278 279 int jffs2_unregister_compressor(struct jffs2_compressor *comp) 280 { 281 D2(struct jffs2_compressor *this;) 282 283 D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name)); 284 285 spin_lock(&jffs2_compressor_list_lock); 286 287 if (comp->usecount) { 288 spin_unlock(&jffs2_compressor_list_lock); 289 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n"); 290 return -1; 291 } 292 list_del(&comp->list); 293 294 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 295 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 296 }) 297 spin_unlock(&jffs2_compressor_list_lock); 298 return 0; 299 } 300 301 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) 302 { 303 if (orig != comprbuf) 304 kfree(comprbuf); 305 } 306 307 int __init jffs2_compressors_init(void) 308 { 309 /* Registering compressors */ 310 #ifdef CONFIG_JFFS2_ZLIB 311 jffs2_zlib_init(); 312 #endif 313 #ifdef CONFIG_JFFS2_RTIME 314 jffs2_rtime_init(); 315 #endif 316 #ifdef CONFIG_JFFS2_RUBIN 317 jffs2_rubinmips_init(); 318 jffs2_dynrubin_init(); 319 #endif 320 #ifdef CONFIG_JFFS2_LZO 321 jffs2_lzo_init(); 322 #endif 323 /* Setting default compression mode */ 324 #ifdef CONFIG_JFFS2_CMODE_NONE 325 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE; 326 D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");) 327 #else 328 #ifdef CONFIG_JFFS2_CMODE_SIZE 329 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE; 330 D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");) 331 #else 332 #ifdef CONFIG_JFFS2_CMODE_FAVOURLZO 333 jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO; 334 D1(printk(KERN_INFO "JFFS2: default compression mode: favourlzo\n");) 335 #else 336 D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");) 337 #endif 338 #endif 339 #endif 340 return 0; 341 } 342 343 int jffs2_compressors_exit(void) 344 { 345 /* Unregistering compressors */ 346 #ifdef CONFIG_JFFS2_LZO 347 jffs2_lzo_exit(); 348 #endif 349 #ifdef CONFIG_JFFS2_RUBIN 350 jffs2_dynrubin_exit(); 351 jffs2_rubinmips_exit(); 352 #endif 353 #ifdef CONFIG_JFFS2_RTIME 354 jffs2_rtime_exit(); 355 #endif 356 #ifdef CONFIG_JFFS2_ZLIB 357 jffs2_zlib_exit(); 358 #endif 359 return 0; 360 } 361