1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright © 2001-2007 Red Hat, Inc. 5 * 6 * Created by David Woodhouse <dwmw2@infradead.org> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/sched.h> 14 #include <linux/slab.h> 15 #include <linux/mtd/mtd.h> 16 #include <linux/pagemap.h> 17 #include <linux/crc32.h> 18 #include <linux/compiler.h> 19 #include "nodelist.h" 20 #include "summary.h" 21 #include "debug.h" 22 23 #define DEFAULT_EMPTY_SCAN_SIZE 256 24 25 #define noisy_printk(noise, args...) do { \ 26 if (*(noise)) { \ 27 printk(KERN_NOTICE args); \ 28 (*(noise))--; \ 29 if (!(*(noise))) { \ 30 printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \ 31 } \ 32 } \ 33 } while(0) 34 35 static uint32_t pseudo_random; 36 37 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 38 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s); 39 40 /* These helper functions _must_ increase ofs and also do the dirty/used space accounting. 41 * Returning an error will abort the mount - bad checksums etc. should just mark the space 42 * as dirty. 43 */ 44 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 45 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s); 46 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 47 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s); 48 49 static inline int min_free(struct jffs2_sb_info *c) 50 { 51 uint32_t min = 2 * sizeof(struct jffs2_raw_inode); 52 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 53 if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize) 54 return c->wbuf_pagesize; 55 #endif 56 return min; 57 58 } 59 60 static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) { 61 if (sector_size < DEFAULT_EMPTY_SCAN_SIZE) 62 return sector_size; 63 else 64 return DEFAULT_EMPTY_SCAN_SIZE; 65 } 66 67 static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb) 68 { 69 int ret; 70 71 if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1))) 72 return ret; 73 if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size))) 74 return ret; 75 /* Turned wasted size into dirty, since we apparently 76 think it's recoverable now. */ 77 jeb->dirty_size += jeb->wasted_size; 78 c->dirty_size += jeb->wasted_size; 79 c->wasted_size -= jeb->wasted_size; 80 jeb->wasted_size = 0; 81 if (VERYDIRTY(c, jeb->dirty_size)) { 82 list_add(&jeb->list, &c->very_dirty_list); 83 } else { 84 list_add(&jeb->list, &c->dirty_list); 85 } 86 return 0; 87 } 88 89 int jffs2_scan_medium(struct jffs2_sb_info *c) 90 { 91 int i, ret; 92 uint32_t empty_blocks = 0, bad_blocks = 0; 93 unsigned char *flashbuf = NULL; 94 uint32_t buf_size = 0; 95 struct jffs2_summary *s = NULL; /* summary info collected by the scan process */ 96 #ifndef __ECOS 97 size_t pointlen, try_size; 98 99 ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen, 100 (void **)&flashbuf, NULL); 101 if (!ret && pointlen < c->mtd->size) { 102 /* Don't muck about if it won't let us point to the whole flash */ 103 D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen)); 104 mtd_unpoint(c->mtd, 0, pointlen); 105 flashbuf = NULL; 106 } 107 if (ret && ret != -EOPNOTSUPP) 108 D1(printk(KERN_DEBUG "MTD point failed %d\n", ret)); 109 #endif 110 if (!flashbuf) { 111 /* For NAND it's quicker to read a whole eraseblock at a time, 112 apparently */ 113 if (jffs2_cleanmarker_oob(c)) 114 try_size = c->sector_size; 115 else 116 try_size = PAGE_SIZE; 117 118 D1(printk(KERN_DEBUG "Trying to allocate readbuf of %zu " 119 "bytes\n", try_size)); 120 121 flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size); 122 if (!flashbuf) 123 return -ENOMEM; 124 125 D1(printk(KERN_DEBUG "Allocated readbuf of %zu bytes\n", 126 try_size)); 127 128 buf_size = (uint32_t)try_size; 129 } 130 131 if (jffs2_sum_active()) { 132 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL); 133 if (!s) { 134 JFFS2_WARNING("Can't allocate memory for summary\n"); 135 ret = -ENOMEM; 136 goto out; 137 } 138 } 139 140 for (i=0; i<c->nr_blocks; i++) { 141 struct jffs2_eraseblock *jeb = &c->blocks[i]; 142 143 cond_resched(); 144 145 /* reset summary info for next eraseblock scan */ 146 jffs2_sum_reset_collected(s); 147 148 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), 149 buf_size, s); 150 151 if (ret < 0) 152 goto out; 153 154 jffs2_dbg_acct_paranoia_check_nolock(c, jeb); 155 156 /* Now decide which list to put it on */ 157 switch(ret) { 158 case BLK_STATE_ALLFF: 159 /* 160 * Empty block. Since we can't be sure it 161 * was entirely erased, we just queue it for erase 162 * again. It will be marked as such when the erase 163 * is complete. Meanwhile we still count it as empty 164 * for later checks. 165 */ 166 empty_blocks++; 167 list_add(&jeb->list, &c->erase_pending_list); 168 c->nr_erasing_blocks++; 169 break; 170 171 case BLK_STATE_CLEANMARKER: 172 /* Only a CLEANMARKER node is valid */ 173 if (!jeb->dirty_size) { 174 /* It's actually free */ 175 list_add(&jeb->list, &c->free_list); 176 c->nr_free_blocks++; 177 } else { 178 /* Dirt */ 179 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset)); 180 list_add(&jeb->list, &c->erase_pending_list); 181 c->nr_erasing_blocks++; 182 } 183 break; 184 185 case BLK_STATE_CLEAN: 186 /* Full (or almost full) of clean data. Clean list */ 187 list_add(&jeb->list, &c->clean_list); 188 break; 189 190 case BLK_STATE_PARTDIRTY: 191 /* Some data, but not full. Dirty list. */ 192 /* We want to remember the block with most free space 193 and stick it in the 'nextblock' position to start writing to it. */ 194 if (jeb->free_size > min_free(c) && 195 (!c->nextblock || c->nextblock->free_size < jeb->free_size)) { 196 /* Better candidate for the next writes to go to */ 197 if (c->nextblock) { 198 ret = file_dirty(c, c->nextblock); 199 if (ret) 200 goto out; 201 /* deleting summary information of the old nextblock */ 202 jffs2_sum_reset_collected(c->summary); 203 } 204 /* update collected summary information for the current nextblock */ 205 jffs2_sum_move_collected(c, s); 206 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset)); 207 c->nextblock = jeb; 208 } else { 209 ret = file_dirty(c, jeb); 210 if (ret) 211 goto out; 212 } 213 break; 214 215 case BLK_STATE_ALLDIRTY: 216 /* Nothing valid - not even a clean marker. Needs erasing. */ 217 /* For now we just put it on the erasing list. We'll start the erases later */ 218 D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset)); 219 list_add(&jeb->list, &c->erase_pending_list); 220 c->nr_erasing_blocks++; 221 break; 222 223 case BLK_STATE_BADBLOCK: 224 D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset)); 225 list_add(&jeb->list, &c->bad_list); 226 c->bad_size += c->sector_size; 227 c->free_size -= c->sector_size; 228 bad_blocks++; 229 break; 230 default: 231 printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n"); 232 BUG(); 233 } 234 } 235 236 /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */ 237 if (c->nextblock && (c->nextblock->dirty_size)) { 238 c->nextblock->wasted_size += c->nextblock->dirty_size; 239 c->wasted_size += c->nextblock->dirty_size; 240 c->dirty_size -= c->nextblock->dirty_size; 241 c->nextblock->dirty_size = 0; 242 } 243 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 244 if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) { 245 /* If we're going to start writing into a block which already 246 contains data, and the end of the data isn't page-aligned, 247 skip a little and align it. */ 248 249 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize; 250 251 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n", 252 skip)); 253 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1); 254 jffs2_scan_dirty_space(c, c->nextblock, skip); 255 } 256 #endif 257 if (c->nr_erasing_blocks) { 258 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) { 259 printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n"); 260 printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks); 261 ret = -EIO; 262 goto out; 263 } 264 spin_lock(&c->erase_completion_lock); 265 jffs2_garbage_collect_trigger(c); 266 spin_unlock(&c->erase_completion_lock); 267 } 268 ret = 0; 269 out: 270 if (buf_size) 271 kfree(flashbuf); 272 #ifndef __ECOS 273 else 274 mtd_unpoint(c->mtd, 0, c->mtd->size); 275 #endif 276 kfree(s); 277 return ret; 278 } 279 280 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf, 281 uint32_t ofs, uint32_t len) 282 { 283 int ret; 284 size_t retlen; 285 286 ret = jffs2_flash_read(c, ofs, len, &retlen, buf); 287 if (ret) { 288 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret)); 289 return ret; 290 } 291 if (retlen < len) { 292 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen)); 293 return -EIO; 294 } 295 return 0; 296 } 297 298 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb) 299 { 300 if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size 301 && (!jeb->first_node || !ref_next(jeb->first_node)) ) 302 return BLK_STATE_CLEANMARKER; 303 304 /* move blocks with max 4 byte dirty space to cleanlist */ 305 else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) { 306 c->dirty_size -= jeb->dirty_size; 307 c->wasted_size += jeb->dirty_size; 308 jeb->wasted_size += jeb->dirty_size; 309 jeb->dirty_size = 0; 310 return BLK_STATE_CLEAN; 311 } else if (jeb->used_size || jeb->unchecked_size) 312 return BLK_STATE_PARTDIRTY; 313 else 314 return BLK_STATE_ALLDIRTY; 315 } 316 317 #ifdef CONFIG_JFFS2_FS_XATTR 318 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 319 struct jffs2_raw_xattr *rx, uint32_t ofs, 320 struct jffs2_summary *s) 321 { 322 struct jffs2_xattr_datum *xd; 323 uint32_t xid, version, totlen, crc; 324 int err; 325 326 crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4); 327 if (crc != je32_to_cpu(rx->node_crc)) { 328 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n", 329 ofs, je32_to_cpu(rx->node_crc), crc); 330 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen)))) 331 return err; 332 return 0; 333 } 334 335 xid = je32_to_cpu(rx->xid); 336 version = je32_to_cpu(rx->version); 337 338 totlen = PAD(sizeof(struct jffs2_raw_xattr) 339 + rx->name_len + 1 + je16_to_cpu(rx->value_len)); 340 if (totlen != je32_to_cpu(rx->totlen)) { 341 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n", 342 ofs, je32_to_cpu(rx->totlen), totlen); 343 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen)))) 344 return err; 345 return 0; 346 } 347 348 xd = jffs2_setup_xattr_datum(c, xid, version); 349 if (IS_ERR(xd)) 350 return PTR_ERR(xd); 351 352 if (xd->version > version) { 353 struct jffs2_raw_node_ref *raw 354 = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL); 355 raw->next_in_ino = xd->node->next_in_ino; 356 xd->node->next_in_ino = raw; 357 } else { 358 xd->version = version; 359 xd->xprefix = rx->xprefix; 360 xd->name_len = rx->name_len; 361 xd->value_len = je16_to_cpu(rx->value_len); 362 xd->data_crc = je32_to_cpu(rx->data_crc); 363 364 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd); 365 } 366 367 if (jffs2_sum_active()) 368 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset); 369 dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n", 370 ofs, xd->xid, xd->version); 371 return 0; 372 } 373 374 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 375 struct jffs2_raw_xref *rr, uint32_t ofs, 376 struct jffs2_summary *s) 377 { 378 struct jffs2_xattr_ref *ref; 379 uint32_t crc; 380 int err; 381 382 crc = crc32(0, rr, sizeof(*rr) - 4); 383 if (crc != je32_to_cpu(rr->node_crc)) { 384 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n", 385 ofs, je32_to_cpu(rr->node_crc), crc); 386 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen))))) 387 return err; 388 return 0; 389 } 390 391 if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) { 392 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n", 393 ofs, je32_to_cpu(rr->totlen), 394 PAD(sizeof(struct jffs2_raw_xref))); 395 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen)))) 396 return err; 397 return 0; 398 } 399 400 ref = jffs2_alloc_xattr_ref(); 401 if (!ref) 402 return -ENOMEM; 403 404 /* BEFORE jffs2_build_xattr_subsystem() called, 405 * and AFTER xattr_ref is marked as a dead xref, 406 * ref->xid is used to store 32bit xid, xd is not used 407 * ref->ino is used to store 32bit inode-number, ic is not used 408 * Thoes variables are declared as union, thus using those 409 * are exclusive. In a similar way, ref->next is temporarily 410 * used to chain all xattr_ref object. It's re-chained to 411 * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly. 412 */ 413 ref->ino = je32_to_cpu(rr->ino); 414 ref->xid = je32_to_cpu(rr->xid); 415 ref->xseqno = je32_to_cpu(rr->xseqno); 416 if (ref->xseqno > c->highest_xseqno) 417 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER); 418 ref->next = c->xref_temp; 419 c->xref_temp = ref; 420 421 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref); 422 423 if (jffs2_sum_active()) 424 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset); 425 dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n", 426 ofs, ref->xid, ref->ino); 427 return 0; 428 } 429 #endif 430 431 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into 432 the flash, XIP-style */ 433 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 434 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) { 435 struct jffs2_unknown_node *node; 436 struct jffs2_unknown_node crcnode; 437 uint32_t ofs, prevofs, max_ofs; 438 uint32_t hdr_crc, buf_ofs, buf_len; 439 int err; 440 int noise = 0; 441 442 443 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 444 int cleanmarkerfound = 0; 445 #endif 446 447 ofs = jeb->offset; 448 prevofs = jeb->offset - 1; 449 450 D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs)); 451 452 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 453 if (jffs2_cleanmarker_oob(c)) { 454 int ret; 455 456 if (mtd_block_isbad(c->mtd, jeb->offset)) 457 return BLK_STATE_BADBLOCK; 458 459 ret = jffs2_check_nand_cleanmarker(c, jeb); 460 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret)); 461 462 /* Even if it's not found, we still scan to see 463 if the block is empty. We use this information 464 to decide whether to erase it or not. */ 465 switch (ret) { 466 case 0: cleanmarkerfound = 1; break; 467 case 1: break; 468 default: return ret; 469 } 470 } 471 #endif 472 473 if (jffs2_sum_active()) { 474 struct jffs2_sum_marker *sm; 475 void *sumptr = NULL; 476 uint32_t sumlen; 477 478 if (!buf_size) { 479 /* XIP case. Just look, point at the summary if it's there */ 480 sm = (void *)buf + c->sector_size - sizeof(*sm); 481 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) { 482 sumptr = buf + je32_to_cpu(sm->offset); 483 sumlen = c->sector_size - je32_to_cpu(sm->offset); 484 } 485 } else { 486 /* If NAND flash, read a whole page of it. Else just the end */ 487 if (c->wbuf_pagesize) 488 buf_len = c->wbuf_pagesize; 489 else 490 buf_len = sizeof(*sm); 491 492 /* Read as much as we want into the _end_ of the preallocated buffer */ 493 err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len, 494 jeb->offset + c->sector_size - buf_len, 495 buf_len); 496 if (err) 497 return err; 498 499 sm = (void *)buf + buf_size - sizeof(*sm); 500 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) { 501 sumlen = c->sector_size - je32_to_cpu(sm->offset); 502 sumptr = buf + buf_size - sumlen; 503 504 /* Now, make sure the summary itself is available */ 505 if (sumlen > buf_size) { 506 /* Need to kmalloc for this. */ 507 sumptr = kmalloc(sumlen, GFP_KERNEL); 508 if (!sumptr) 509 return -ENOMEM; 510 memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len); 511 } 512 if (buf_len < sumlen) { 513 /* Need to read more so that the entire summary node is present */ 514 err = jffs2_fill_scan_buf(c, sumptr, 515 jeb->offset + c->sector_size - sumlen, 516 sumlen - buf_len); 517 if (err) 518 return err; 519 } 520 } 521 522 } 523 524 if (sumptr) { 525 err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random); 526 527 if (buf_size && sumlen > buf_size) 528 kfree(sumptr); 529 /* If it returns with a real error, bail. 530 If it returns positive, that's a block classification 531 (i.e. BLK_STATE_xxx) so return that too. 532 If it returns zero, fall through to full scan. */ 533 if (err) 534 return err; 535 } 536 } 537 538 buf_ofs = jeb->offset; 539 540 if (!buf_size) { 541 /* This is the XIP case -- we're reading _directly_ from the flash chip */ 542 buf_len = c->sector_size; 543 } else { 544 buf_len = EMPTY_SCAN_SIZE(c->sector_size); 545 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len); 546 if (err) 547 return err; 548 } 549 550 /* We temporarily use 'ofs' as a pointer into the buffer/jeb */ 551 ofs = 0; 552 max_ofs = EMPTY_SCAN_SIZE(c->sector_size); 553 /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */ 554 while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF) 555 ofs += 4; 556 557 if (ofs == max_ofs) { 558 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 559 if (jffs2_cleanmarker_oob(c)) { 560 /* scan oob, take care of cleanmarker */ 561 int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound); 562 D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret)); 563 switch (ret) { 564 case 0: return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF; 565 case 1: return BLK_STATE_ALLDIRTY; 566 default: return ret; 567 } 568 } 569 #endif 570 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset)); 571 if (c->cleanmarker_size == 0) 572 return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */ 573 else 574 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */ 575 } 576 if (ofs) { 577 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset, 578 jeb->offset + ofs)); 579 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1))) 580 return err; 581 if ((err = jffs2_scan_dirty_space(c, jeb, ofs))) 582 return err; 583 } 584 585 /* Now ofs is a complete physical flash offset as it always was... */ 586 ofs += jeb->offset; 587 588 noise = 10; 589 590 dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset); 591 592 scan_more: 593 while(ofs < jeb->offset + c->sector_size) { 594 595 jffs2_dbg_acct_paranoia_check_nolock(c, jeb); 596 597 /* Make sure there are node refs available for use */ 598 err = jffs2_prealloc_raw_node_refs(c, jeb, 2); 599 if (err) 600 return err; 601 602 cond_resched(); 603 604 if (ofs & 3) { 605 printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs); 606 ofs = PAD(ofs); 607 continue; 608 } 609 if (ofs == prevofs) { 610 printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs); 611 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 612 return err; 613 ofs += 4; 614 continue; 615 } 616 prevofs = ofs; 617 618 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) { 619 D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading\n", sizeof(struct jffs2_unknown_node), 620 jeb->offset, c->sector_size, ofs, sizeof(*node))); 621 if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs))) 622 return err; 623 break; 624 } 625 626 if (buf_ofs + buf_len < ofs + sizeof(*node)) { 627 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 628 D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n", 629 sizeof(struct jffs2_unknown_node), buf_len, ofs)); 630 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 631 if (err) 632 return err; 633 buf_ofs = ofs; 634 } 635 636 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs]; 637 638 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) { 639 uint32_t inbuf_ofs; 640 uint32_t empty_start, scan_end; 641 642 empty_start = ofs; 643 ofs += 4; 644 scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len); 645 646 D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs)); 647 more_empty: 648 inbuf_ofs = ofs - buf_ofs; 649 while (inbuf_ofs < scan_end) { 650 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) { 651 printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n", 652 empty_start, ofs); 653 if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start))) 654 return err; 655 goto scan_more; 656 } 657 658 inbuf_ofs+=4; 659 ofs += 4; 660 } 661 /* Ran off end. */ 662 D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs)); 663 664 /* If we're only checking the beginning of a block with a cleanmarker, 665 bail now */ 666 if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 667 c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) { 668 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size))); 669 return BLK_STATE_CLEANMARKER; 670 } 671 if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */ 672 scan_end = buf_len; 673 goto more_empty; 674 } 675 676 /* See how much more there is to read in this eraseblock... */ 677 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 678 if (!buf_len) { 679 /* No more to read. Break out of main loop without marking 680 this range of empty space as dirty (because it's not) */ 681 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n", 682 empty_start)); 683 break; 684 } 685 /* point never reaches here */ 686 scan_end = buf_len; 687 D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs)); 688 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 689 if (err) 690 return err; 691 buf_ofs = ofs; 692 goto more_empty; 693 } 694 695 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) { 696 printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs); 697 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 698 return err; 699 ofs += 4; 700 continue; 701 } 702 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) { 703 D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs)); 704 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 705 return err; 706 ofs += 4; 707 continue; 708 } 709 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) { 710 printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs); 711 printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n"); 712 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 713 return err; 714 ofs += 4; 715 continue; 716 } 717 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) { 718 /* OK. We're out of possibilities. Whinge and move on */ 719 noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n", 720 JFFS2_MAGIC_BITMASK, ofs, 721 je16_to_cpu(node->magic)); 722 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 723 return err; 724 ofs += 4; 725 continue; 726 } 727 /* We seem to have a node of sorts. Check the CRC */ 728 crcnode.magic = node->magic; 729 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE); 730 crcnode.totlen = node->totlen; 731 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4); 732 733 if (hdr_crc != je32_to_cpu(node->hdr_crc)) { 734 noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)\n", 735 ofs, je16_to_cpu(node->magic), 736 je16_to_cpu(node->nodetype), 737 je32_to_cpu(node->totlen), 738 je32_to_cpu(node->hdr_crc), 739 hdr_crc); 740 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 741 return err; 742 ofs += 4; 743 continue; 744 } 745 746 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) { 747 /* Eep. Node goes over the end of the erase block. */ 748 printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n", 749 ofs, je32_to_cpu(node->totlen)); 750 printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n"); 751 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 752 return err; 753 ofs += 4; 754 continue; 755 } 756 757 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) { 758 /* Wheee. This is an obsoleted node */ 759 D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs)); 760 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 761 return err; 762 ofs += PAD(je32_to_cpu(node->totlen)); 763 continue; 764 } 765 766 switch(je16_to_cpu(node->nodetype)) { 767 case JFFS2_NODETYPE_INODE: 768 if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) { 769 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 770 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n", 771 sizeof(struct jffs2_raw_inode), buf_len, ofs)); 772 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 773 if (err) 774 return err; 775 buf_ofs = ofs; 776 node = (void *)buf; 777 } 778 err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s); 779 if (err) return err; 780 ofs += PAD(je32_to_cpu(node->totlen)); 781 break; 782 783 case JFFS2_NODETYPE_DIRENT: 784 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 785 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 786 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n", 787 je32_to_cpu(node->totlen), buf_len, ofs)); 788 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 789 if (err) 790 return err; 791 buf_ofs = ofs; 792 node = (void *)buf; 793 } 794 err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s); 795 if (err) return err; 796 ofs += PAD(je32_to_cpu(node->totlen)); 797 break; 798 799 #ifdef CONFIG_JFFS2_FS_XATTR 800 case JFFS2_NODETYPE_XATTR: 801 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 802 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 803 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)" 804 " left to end of buf. Reading 0x%x at 0x%08x\n", 805 je32_to_cpu(node->totlen), buf_len, ofs)); 806 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 807 if (err) 808 return err; 809 buf_ofs = ofs; 810 node = (void *)buf; 811 } 812 err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s); 813 if (err) 814 return err; 815 ofs += PAD(je32_to_cpu(node->totlen)); 816 break; 817 case JFFS2_NODETYPE_XREF: 818 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 819 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 820 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)" 821 " left to end of buf. Reading 0x%x at 0x%08x\n", 822 je32_to_cpu(node->totlen), buf_len, ofs)); 823 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 824 if (err) 825 return err; 826 buf_ofs = ofs; 827 node = (void *)buf; 828 } 829 err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s); 830 if (err) 831 return err; 832 ofs += PAD(je32_to_cpu(node->totlen)); 833 break; 834 #endif /* CONFIG_JFFS2_FS_XATTR */ 835 836 case JFFS2_NODETYPE_CLEANMARKER: 837 D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs)); 838 if (je32_to_cpu(node->totlen) != c->cleanmarker_size) { 839 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n", 840 ofs, je32_to_cpu(node->totlen), c->cleanmarker_size); 841 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node))))) 842 return err; 843 ofs += PAD(sizeof(struct jffs2_unknown_node)); 844 } else if (jeb->first_node) { 845 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset); 846 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node))))) 847 return err; 848 ofs += PAD(sizeof(struct jffs2_unknown_node)); 849 } else { 850 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL); 851 852 ofs += PAD(c->cleanmarker_size); 853 } 854 break; 855 856 case JFFS2_NODETYPE_PADDING: 857 if (jffs2_sum_active()) 858 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen)); 859 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 860 return err; 861 ofs += PAD(je32_to_cpu(node->totlen)); 862 break; 863 864 default: 865 switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) { 866 case JFFS2_FEATURE_ROCOMPAT: 867 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs); 868 c->flags |= JFFS2_SB_FLAG_RO; 869 if (!(jffs2_is_readonly(c))) 870 return -EROFS; 871 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 872 return err; 873 ofs += PAD(je32_to_cpu(node->totlen)); 874 break; 875 876 case JFFS2_FEATURE_INCOMPAT: 877 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs); 878 return -EINVAL; 879 880 case JFFS2_FEATURE_RWCOMPAT_DELETE: 881 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs)); 882 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 883 return err; 884 ofs += PAD(je32_to_cpu(node->totlen)); 885 break; 886 887 case JFFS2_FEATURE_RWCOMPAT_COPY: { 888 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs)); 889 890 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL); 891 892 /* We can't summarise nodes we don't grok */ 893 jffs2_sum_disable_collecting(s); 894 ofs += PAD(je32_to_cpu(node->totlen)); 895 break; 896 } 897 } 898 } 899 } 900 901 if (jffs2_sum_active()) { 902 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) { 903 dbg_summary("There is not enough space for " 904 "summary information, disabling for this jeb!\n"); 905 jffs2_sum_disable_collecting(s); 906 } 907 } 908 909 D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n", 910 jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size)); 911 912 /* mark_node_obsolete can add to wasted !! */ 913 if (jeb->wasted_size) { 914 jeb->dirty_size += jeb->wasted_size; 915 c->dirty_size += jeb->wasted_size; 916 c->wasted_size -= jeb->wasted_size; 917 jeb->wasted_size = 0; 918 } 919 920 return jffs2_scan_classify_jeb(c, jeb); 921 } 922 923 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino) 924 { 925 struct jffs2_inode_cache *ic; 926 927 ic = jffs2_get_ino_cache(c, ino); 928 if (ic) 929 return ic; 930 931 if (ino > c->highest_ino) 932 c->highest_ino = ino; 933 934 ic = jffs2_alloc_inode_cache(); 935 if (!ic) { 936 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n"); 937 return NULL; 938 } 939 memset(ic, 0, sizeof(*ic)); 940 941 ic->ino = ino; 942 ic->nodes = (void *)ic; 943 jffs2_add_ino_cache(c, ic); 944 if (ino == 1) 945 ic->pino_nlink = 1; 946 return ic; 947 } 948 949 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 950 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s) 951 { 952 struct jffs2_inode_cache *ic; 953 uint32_t crc, ino = je32_to_cpu(ri->ino); 954 955 D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs)); 956 957 /* We do very little here now. Just check the ino# to which we should attribute 958 this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 959 we used to scan the flash once only, reading everything we want from it into 960 memory, then building all our in-core data structures and freeing the extra 961 information. Now we allow the first part of the mount to complete a lot quicker, 962 but we have to go _back_ to the flash in order to finish the CRC checking, etc. 963 Which means that the _full_ amount of time to get to proper write mode with GC 964 operational may actually be _longer_ than before. Sucks to be me. */ 965 966 /* Check the node CRC in any case. */ 967 crc = crc32(0, ri, sizeof(*ri)-8); 968 if (crc != je32_to_cpu(ri->node_crc)) { 969 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on " 970 "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 971 ofs, je32_to_cpu(ri->node_crc), crc); 972 /* 973 * We believe totlen because the CRC on the node 974 * _header_ was OK, just the node itself failed. 975 */ 976 return jffs2_scan_dirty_space(c, jeb, 977 PAD(je32_to_cpu(ri->totlen))); 978 } 979 980 ic = jffs2_get_ino_cache(c, ino); 981 if (!ic) { 982 ic = jffs2_scan_make_ino_cache(c, ino); 983 if (!ic) 984 return -ENOMEM; 985 } 986 987 /* Wheee. It worked */ 988 jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic); 989 990 D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n", 991 je32_to_cpu(ri->ino), je32_to_cpu(ri->version), 992 je32_to_cpu(ri->offset), 993 je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize))); 994 995 pseudo_random += je32_to_cpu(ri->version); 996 997 if (jffs2_sum_active()) { 998 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset); 999 } 1000 1001 return 0; 1002 } 1003 1004 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 1005 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s) 1006 { 1007 struct jffs2_full_dirent *fd; 1008 struct jffs2_inode_cache *ic; 1009 uint32_t checkedlen; 1010 uint32_t crc; 1011 int err; 1012 1013 D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs)); 1014 1015 /* We don't get here unless the node is still valid, so we don't have to 1016 mask in the ACCURATE bit any more. */ 1017 crc = crc32(0, rd, sizeof(*rd)-8); 1018 1019 if (crc != je32_to_cpu(rd->node_crc)) { 1020 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 1021 ofs, je32_to_cpu(rd->node_crc), crc); 1022 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */ 1023 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen))))) 1024 return err; 1025 return 0; 1026 } 1027 1028 pseudo_random += je32_to_cpu(rd->version); 1029 1030 /* Should never happen. Did. (OLPC trac #4184)*/ 1031 checkedlen = strnlen(rd->name, rd->nsize); 1032 if (checkedlen < rd->nsize) { 1033 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n", 1034 ofs, checkedlen); 1035 } 1036 fd = jffs2_alloc_full_dirent(checkedlen+1); 1037 if (!fd) { 1038 return -ENOMEM; 1039 } 1040 memcpy(&fd->name, rd->name, checkedlen); 1041 fd->name[checkedlen] = 0; 1042 1043 crc = crc32(0, fd->name, rd->nsize); 1044 if (crc != je32_to_cpu(rd->name_crc)) { 1045 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 1046 ofs, je32_to_cpu(rd->name_crc), crc); 1047 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino))); 1048 jffs2_free_full_dirent(fd); 1049 /* FIXME: Why do we believe totlen? */ 1050 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */ 1051 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen))))) 1052 return err; 1053 return 0; 1054 } 1055 ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino)); 1056 if (!ic) { 1057 jffs2_free_full_dirent(fd); 1058 return -ENOMEM; 1059 } 1060 1061 fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd), 1062 PAD(je32_to_cpu(rd->totlen)), ic); 1063 1064 fd->next = NULL; 1065 fd->version = je32_to_cpu(rd->version); 1066 fd->ino = je32_to_cpu(rd->ino); 1067 fd->nhash = full_name_hash(fd->name, checkedlen); 1068 fd->type = rd->type; 1069 jffs2_add_fd_to_list(c, fd, &ic->scan_dents); 1070 1071 if (jffs2_sum_active()) { 1072 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset); 1073 } 1074 1075 return 0; 1076 } 1077 1078 static int count_list(struct list_head *l) 1079 { 1080 uint32_t count = 0; 1081 struct list_head *tmp; 1082 1083 list_for_each(tmp, l) { 1084 count++; 1085 } 1086 return count; 1087 } 1088 1089 /* Note: This breaks if list_empty(head). I don't care. You 1090 might, if you copy this code and use it elsewhere :) */ 1091 static void rotate_list(struct list_head *head, uint32_t count) 1092 { 1093 struct list_head *n = head->next; 1094 1095 list_del(head); 1096 while(count--) { 1097 n = n->next; 1098 } 1099 list_add(head, n); 1100 } 1101 1102 void jffs2_rotate_lists(struct jffs2_sb_info *c) 1103 { 1104 uint32_t x; 1105 uint32_t rotateby; 1106 1107 x = count_list(&c->clean_list); 1108 if (x) { 1109 rotateby = pseudo_random % x; 1110 rotate_list((&c->clean_list), rotateby); 1111 } 1112 1113 x = count_list(&c->very_dirty_list); 1114 if (x) { 1115 rotateby = pseudo_random % x; 1116 rotate_list((&c->very_dirty_list), rotateby); 1117 } 1118 1119 x = count_list(&c->dirty_list); 1120 if (x) { 1121 rotateby = pseudo_random % x; 1122 rotate_list((&c->dirty_list), rotateby); 1123 } 1124 1125 x = count_list(&c->erasable_list); 1126 if (x) { 1127 rotateby = pseudo_random % x; 1128 rotate_list((&c->erasable_list), rotateby); 1129 } 1130 1131 if (c->nr_erasing_blocks) { 1132 rotateby = pseudo_random % c->nr_erasing_blocks; 1133 rotate_list((&c->erase_pending_list), rotateby); 1134 } 1135 1136 if (c->nr_free_blocks) { 1137 rotateby = pseudo_random % c->nr_free_blocks; 1138 rotate_list((&c->free_list), rotateby); 1139 } 1140 } 1141