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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 16 17 #include "compr.h" 18 19 static DEFINE_SPINLOCK(jffs2_compressor_list_lock); 20 21 /* Available compressors are on this list */ 22 static LIST_HEAD(jffs2_compressor_list); 23 24 /* Actual compression mode */ 25 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY; 26 27 /* Statistics for blocks stored without compression */ 28 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0; 29 30 31 /* 32 * Return 1 to use this compression 33 */ 34 static int jffs2_is_best_compression(struct jffs2_compressor *this, 35 struct jffs2_compressor *best, uint32_t size, uint32_t bestsize) 36 { 37 switch (jffs2_compression_mode) { 38 case JFFS2_COMPR_MODE_SIZE: 39 if (bestsize > size) 40 return 1; 41 return 0; 42 case JFFS2_COMPR_MODE_FAVOURLZO: 43 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size)) 44 return 1; 45 if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size)) 46 return 1; 47 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100))) 48 return 1; 49 if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size) 50 return 1; 51 52 return 0; 53 } 54 /* Shouldn't happen */ 55 return 0; 56 } 57 58 /* 59 * jffs2_selected_compress: 60 * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB). 61 * If 0, just take the first available compression mode. 62 * @data_in: Pointer to uncompressed data 63 * @cpage_out: Pointer to returned pointer to buffer for compressed data 64 * @datalen: On entry, holds the amount of data available for compression. 65 * On exit, expected to hold the amount of data actually compressed. 66 * @cdatalen: On entry, holds the amount of space available for compressed 67 * data. On exit, expected to hold the actual size of the compressed 68 * data. 69 * 70 * Returns: the compression type used. Zero is used to show that the data 71 * could not be compressed; probably because we couldn't find the requested 72 * compression mode. 73 */ 74 static int jffs2_selected_compress(u8 compr, unsigned char *data_in, 75 unsigned char **cpage_out, u32 *datalen, u32 *cdatalen) 76 { 77 struct jffs2_compressor *this; 78 int err, ret = JFFS2_COMPR_NONE; 79 uint32_t orig_slen, orig_dlen; 80 char *output_buf; 81 82 output_buf = kmalloc(*cdatalen, GFP_KERNEL); 83 if (!output_buf) { 84 pr_warn("No memory for compressor allocation. Compression failed.\n"); 85 return ret; 86 } 87 orig_slen = *datalen; 88 orig_dlen = *cdatalen; 89 spin_lock(&jffs2_compressor_list_lock); 90 list_for_each_entry(this, &jffs2_compressor_list, list) { 91 /* Skip decompress-only and disabled modules */ 92 if (!this->compress || this->disabled) 93 continue; 94 95 /* Skip if not the desired compression type */ 96 if (compr && (compr != this->compr)) 97 continue; 98 99 /* 100 * Either compression type was unspecified, or we found our 101 * compressor; either way, we're good to go. 102 */ 103 this->usecount++; 104 spin_unlock(&jffs2_compressor_list_lock); 105 106 *datalen = orig_slen; 107 *cdatalen = orig_dlen; 108 err = this->compress(data_in, output_buf, datalen, cdatalen); 109 110 spin_lock(&jffs2_compressor_list_lock); 111 this->usecount--; 112 if (!err) { 113 /* Success */ 114 ret = this->compr; 115 this->stat_compr_blocks++; 116 this->stat_compr_orig_size += *datalen; 117 this->stat_compr_new_size += *cdatalen; 118 break; 119 } 120 } 121 spin_unlock(&jffs2_compressor_list_lock); 122 if (ret == JFFS2_COMPR_NONE) 123 kfree(output_buf); 124 else 125 *cpage_out = output_buf; 126 127 return ret; 128 } 129 130 /* jffs2_compress: 131 * @data_in: Pointer to uncompressed data 132 * @cpage_out: Pointer to returned pointer to buffer for compressed data 133 * @datalen: On entry, holds the amount of data available for compression. 134 * On exit, expected to hold the amount of data actually compressed. 135 * @cdatalen: On entry, holds the amount of space available for compressed 136 * data. On exit, expected to hold the actual size of the compressed 137 * data. 138 * 139 * Returns: Lower byte to be stored with data indicating compression type used. 140 * Zero is used to show that the data could not be compressed - the 141 * compressed version was actually larger than the original. 142 * Upper byte will be used later. (soon) 143 * 144 * If the cdata buffer isn't large enough to hold all the uncompressed data, 145 * jffs2_compress should compress as much as will fit, and should set 146 * *datalen accordingly to show the amount of data which were compressed. 147 */ 148 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 149 unsigned char *data_in, unsigned char **cpage_out, 150 uint32_t *datalen, uint32_t *cdatalen) 151 { 152 int ret = JFFS2_COMPR_NONE; 153 int mode, compr_ret; 154 struct jffs2_compressor *this, *best=NULL; 155 unsigned char *output_buf = NULL, *tmp_buf; 156 uint32_t orig_slen, orig_dlen; 157 uint32_t best_slen=0, best_dlen=0; 158 159 if (c->mount_opts.override_compr) 160 mode = c->mount_opts.compr; 161 else 162 mode = jffs2_compression_mode; 163 164 switch (mode) { 165 case JFFS2_COMPR_MODE_NONE: 166 break; 167 case JFFS2_COMPR_MODE_PRIORITY: 168 ret = jffs2_selected_compress(0, data_in, cpage_out, datalen, 169 cdatalen); 170 break; 171 case JFFS2_COMPR_MODE_SIZE: 172 case JFFS2_COMPR_MODE_FAVOURLZO: 173 orig_slen = *datalen; 174 orig_dlen = *cdatalen; 175 spin_lock(&jffs2_compressor_list_lock); 176 list_for_each_entry(this, &jffs2_compressor_list, list) { 177 /* Skip decompress-only backwards-compatibility and disabled modules */ 178 if ((!this->compress)||(this->disabled)) 179 continue; 180 /* Allocating memory for output buffer if necessary */ 181 if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) { 182 spin_unlock(&jffs2_compressor_list_lock); 183 kfree(this->compr_buf); 184 spin_lock(&jffs2_compressor_list_lock); 185 this->compr_buf_size=0; 186 this->compr_buf=NULL; 187 } 188 if (!this->compr_buf) { 189 spin_unlock(&jffs2_compressor_list_lock); 190 tmp_buf = kmalloc(orig_slen, GFP_KERNEL); 191 spin_lock(&jffs2_compressor_list_lock); 192 if (!tmp_buf) { 193 pr_warn("No memory for compressor allocation. (%d bytes)\n", 194 orig_slen); 195 continue; 196 } 197 else { 198 this->compr_buf = tmp_buf; 199 this->compr_buf_size = orig_slen; 200 } 201 } 202 this->usecount++; 203 spin_unlock(&jffs2_compressor_list_lock); 204 *datalen = orig_slen; 205 *cdatalen = orig_dlen; 206 compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen); 207 spin_lock(&jffs2_compressor_list_lock); 208 this->usecount--; 209 if (!compr_ret) { 210 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen)) 211 && (*cdatalen < *datalen)) { 212 best_dlen = *cdatalen; 213 best_slen = *datalen; 214 best = this; 215 } 216 } 217 } 218 if (best_dlen) { 219 *cdatalen = best_dlen; 220 *datalen = best_slen; 221 output_buf = best->compr_buf; 222 best->compr_buf = NULL; 223 best->compr_buf_size = 0; 224 best->stat_compr_blocks++; 225 best->stat_compr_orig_size += best_slen; 226 best->stat_compr_new_size += best_dlen; 227 ret = best->compr; 228 *cpage_out = output_buf; 229 } 230 spin_unlock(&jffs2_compressor_list_lock); 231 break; 232 case JFFS2_COMPR_MODE_FORCELZO: 233 ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in, 234 cpage_out, datalen, cdatalen); 235 break; 236 case JFFS2_COMPR_MODE_FORCEZLIB: 237 ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in, 238 cpage_out, datalen, cdatalen); 239 break; 240 default: 241 pr_err("unknown compression mode\n"); 242 } 243 244 if (ret == JFFS2_COMPR_NONE) { 245 *cpage_out = data_in; 246 *datalen = *cdatalen; 247 none_stat_compr_blocks++; 248 none_stat_compr_size += *datalen; 249 } 250 return ret; 251 } 252 253 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 254 uint16_t comprtype, unsigned char *cdata_in, 255 unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) 256 { 257 struct jffs2_compressor *this; 258 int ret; 259 260 /* Older code had a bug where it would write non-zero 'usercompr' 261 fields. Deal with it. */ 262 if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) 263 comprtype &= 0xff; 264 265 switch (comprtype & 0xff) { 266 case JFFS2_COMPR_NONE: 267 /* This should be special-cased elsewhere, but we might as well deal with it */ 268 memcpy(data_out, cdata_in, datalen); 269 none_stat_decompr_blocks++; 270 break; 271 case JFFS2_COMPR_ZERO: 272 memset(data_out, 0, datalen); 273 break; 274 default: 275 spin_lock(&jffs2_compressor_list_lock); 276 list_for_each_entry(this, &jffs2_compressor_list, list) { 277 if (comprtype == this->compr) { 278 this->usecount++; 279 spin_unlock(&jffs2_compressor_list_lock); 280 ret = this->decompress(cdata_in, data_out, cdatalen, datalen); 281 spin_lock(&jffs2_compressor_list_lock); 282 if (ret) { 283 pr_warn("Decompressor \"%s\" returned %d\n", 284 this->name, ret); 285 } 286 else { 287 this->stat_decompr_blocks++; 288 } 289 this->usecount--; 290 spin_unlock(&jffs2_compressor_list_lock); 291 return ret; 292 } 293 } 294 pr_warn("compression type 0x%02x not available\n", comprtype); 295 spin_unlock(&jffs2_compressor_list_lock); 296 return -EIO; 297 } 298 return 0; 299 } 300 301 int jffs2_register_compressor(struct jffs2_compressor *comp) 302 { 303 struct jffs2_compressor *this; 304 305 if (!comp->name) { 306 pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n"); 307 return -1; 308 } 309 comp->compr_buf_size=0; 310 comp->compr_buf=NULL; 311 comp->usecount=0; 312 comp->stat_compr_orig_size=0; 313 comp->stat_compr_new_size=0; 314 comp->stat_compr_blocks=0; 315 comp->stat_decompr_blocks=0; 316 jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name); 317 318 spin_lock(&jffs2_compressor_list_lock); 319 320 list_for_each_entry(this, &jffs2_compressor_list, list) { 321 if (this->priority < comp->priority) { 322 list_add(&comp->list, this->list.prev); 323 goto out; 324 } 325 } 326 list_add_tail(&comp->list, &jffs2_compressor_list); 327 out: 328 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 329 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 330 }) 331 332 spin_unlock(&jffs2_compressor_list_lock); 333 334 return 0; 335 } 336 337 int jffs2_unregister_compressor(struct jffs2_compressor *comp) 338 { 339 D2(struct jffs2_compressor *this); 340 341 jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name); 342 343 spin_lock(&jffs2_compressor_list_lock); 344 345 if (comp->usecount) { 346 spin_unlock(&jffs2_compressor_list_lock); 347 pr_warn("Compressor module is in use. Unregister failed.\n"); 348 return -1; 349 } 350 list_del(&comp->list); 351 352 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 353 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 354 }) 355 spin_unlock(&jffs2_compressor_list_lock); 356 return 0; 357 } 358 359 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) 360 { 361 if (orig != comprbuf) 362 kfree(comprbuf); 363 } 364 365 int __init jffs2_compressors_init(void) 366 { 367 /* Registering compressors */ 368 #ifdef CONFIG_JFFS2_ZLIB 369 jffs2_zlib_init(); 370 #endif 371 #ifdef CONFIG_JFFS2_RTIME 372 jffs2_rtime_init(); 373 #endif 374 #ifdef CONFIG_JFFS2_RUBIN 375 jffs2_rubinmips_init(); 376 jffs2_dynrubin_init(); 377 #endif 378 #ifdef CONFIG_JFFS2_LZO 379 jffs2_lzo_init(); 380 #endif 381 /* Setting default compression mode */ 382 #ifdef CONFIG_JFFS2_CMODE_NONE 383 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE; 384 jffs2_dbg(1, "default compression mode: none\n"); 385 #else 386 #ifdef CONFIG_JFFS2_CMODE_SIZE 387 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE; 388 jffs2_dbg(1, "default compression mode: size\n"); 389 #else 390 #ifdef CONFIG_JFFS2_CMODE_FAVOURLZO 391 jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO; 392 jffs2_dbg(1, "default compression mode: favourlzo\n"); 393 #else 394 jffs2_dbg(1, "default compression mode: priority\n"); 395 #endif 396 #endif 397 #endif 398 return 0; 399 } 400 401 int jffs2_compressors_exit(void) 402 { 403 /* Unregistering compressors */ 404 #ifdef CONFIG_JFFS2_LZO 405 jffs2_lzo_exit(); 406 #endif 407 #ifdef CONFIG_JFFS2_RUBIN 408 jffs2_dynrubin_exit(); 409 jffs2_rubinmips_exit(); 410 #endif 411 #ifdef CONFIG_JFFS2_RTIME 412 jffs2_rtime_exit(); 413 #endif 414 #ifdef CONFIG_JFFS2_ZLIB 415 jffs2_zlib_exit(); 416 #endif 417 return 0; 418 } 419