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; 98 99 if (c->mtd->point) { 100 ret = c->mtd->point(c->mtd, 0, c->mtd->size, &pointlen, 101 (void **)&flashbuf, NULL); 102 if (!ret && pointlen < c->mtd->size) { 103 /* Don't muck about if it won't let us point to the whole flash */ 104 D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n", pointlen)); 105 c->mtd->unpoint(c->mtd, 0, pointlen); 106 flashbuf = NULL; 107 } 108 if (ret) 109 D1(printk(KERN_DEBUG "MTD point failed %d\n", ret)); 110 } 111 #endif 112 if (!flashbuf) { 113 /* For NAND it's quicker to read a whole eraseblock at a time, 114 apparently */ 115 if (jffs2_cleanmarker_oob(c)) 116 buf_size = c->sector_size; 117 else 118 buf_size = PAGE_SIZE; 119 120 /* Respect kmalloc limitations */ 121 if (buf_size > 128*1024) 122 buf_size = 128*1024; 123 124 D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size)); 125 flashbuf = kmalloc(buf_size, GFP_KERNEL); 126 if (!flashbuf) 127 return -ENOMEM; 128 } 129 130 if (jffs2_sum_active()) { 131 s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL); 132 if (!s) { 133 JFFS2_WARNING("Can't allocate memory for summary\n"); 134 ret = -ENOMEM; 135 goto out; 136 } 137 } 138 139 for (i=0; i<c->nr_blocks; i++) { 140 struct jffs2_eraseblock *jeb = &c->blocks[i]; 141 142 cond_resched(); 143 144 /* reset summary info for next eraseblock scan */ 145 jffs2_sum_reset_collected(s); 146 147 ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset), 148 buf_size, s); 149 150 if (ret < 0) 151 goto out; 152 153 jffs2_dbg_acct_paranoia_check_nolock(c, jeb); 154 155 /* Now decide which list to put it on */ 156 switch(ret) { 157 case BLK_STATE_ALLFF: 158 /* 159 * Empty block. Since we can't be sure it 160 * was entirely erased, we just queue it for erase 161 * again. It will be marked as such when the erase 162 * is complete. Meanwhile we still count it as empty 163 * for later checks. 164 */ 165 empty_blocks++; 166 list_add(&jeb->list, &c->erase_pending_list); 167 c->nr_erasing_blocks++; 168 break; 169 170 case BLK_STATE_CLEANMARKER: 171 /* Only a CLEANMARKER node is valid */ 172 if (!jeb->dirty_size) { 173 /* It's actually free */ 174 list_add(&jeb->list, &c->free_list); 175 c->nr_free_blocks++; 176 } else { 177 /* Dirt */ 178 D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x to erase_pending_list\n", jeb->offset)); 179 list_add(&jeb->list, &c->erase_pending_list); 180 c->nr_erasing_blocks++; 181 } 182 break; 183 184 case BLK_STATE_CLEAN: 185 /* Full (or almost full) of clean data. Clean list */ 186 list_add(&jeb->list, &c->clean_list); 187 break; 188 189 case BLK_STATE_PARTDIRTY: 190 /* Some data, but not full. Dirty list. */ 191 /* We want to remember the block with most free space 192 and stick it in the 'nextblock' position to start writing to it. */ 193 if (jeb->free_size > min_free(c) && 194 (!c->nextblock || c->nextblock->free_size < jeb->free_size)) { 195 /* Better candidate for the next writes to go to */ 196 if (c->nextblock) { 197 ret = file_dirty(c, c->nextblock); 198 if (ret) 199 goto out; 200 /* deleting summary information of the old nextblock */ 201 jffs2_sum_reset_collected(c->summary); 202 } 203 /* update collected summary information for the current nextblock */ 204 jffs2_sum_move_collected(c, s); 205 D1(printk(KERN_DEBUG "jffs2_scan_medium(): new nextblock = 0x%08x\n", jeb->offset)); 206 c->nextblock = jeb; 207 } else { 208 ret = file_dirty(c, jeb); 209 if (ret) 210 goto out; 211 } 212 break; 213 214 case BLK_STATE_ALLDIRTY: 215 /* Nothing valid - not even a clean marker. Needs erasing. */ 216 /* For now we just put it on the erasing list. We'll start the erases later */ 217 D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not formatted. It will be erased\n", jeb->offset)); 218 list_add(&jeb->list, &c->erase_pending_list); 219 c->nr_erasing_blocks++; 220 break; 221 222 case BLK_STATE_BADBLOCK: 223 D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n", jeb->offset)); 224 list_add(&jeb->list, &c->bad_list); 225 c->bad_size += c->sector_size; 226 c->free_size -= c->sector_size; 227 bad_blocks++; 228 break; 229 default: 230 printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n"); 231 BUG(); 232 } 233 } 234 235 /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */ 236 if (c->nextblock && (c->nextblock->dirty_size)) { 237 c->nextblock->wasted_size += c->nextblock->dirty_size; 238 c->wasted_size += c->nextblock->dirty_size; 239 c->dirty_size -= c->nextblock->dirty_size; 240 c->nextblock->dirty_size = 0; 241 } 242 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 243 if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) { 244 /* If we're going to start writing into a block which already 245 contains data, and the end of the data isn't page-aligned, 246 skip a little and align it. */ 247 248 uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize; 249 250 D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in nextblock to ensure page alignment\n", 251 skip)); 252 jffs2_prealloc_raw_node_refs(c, c->nextblock, 1); 253 jffs2_scan_dirty_space(c, c->nextblock, skip); 254 } 255 #endif 256 if (c->nr_erasing_blocks) { 257 if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) { 258 printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n"); 259 printk(KERN_NOTICE "empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",empty_blocks,bad_blocks,c->nr_blocks); 260 ret = -EIO; 261 goto out; 262 } 263 spin_lock(&c->erase_completion_lock); 264 jffs2_garbage_collect_trigger(c); 265 spin_unlock(&c->erase_completion_lock); 266 } 267 ret = 0; 268 out: 269 if (buf_size) 270 kfree(flashbuf); 271 #ifndef __ECOS 272 else 273 c->mtd->unpoint(c->mtd, 0, c->mtd->size); 274 #endif 275 if (s) 276 kfree(s); 277 278 return ret; 279 } 280 281 static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf, 282 uint32_t ofs, uint32_t len) 283 { 284 int ret; 285 size_t retlen; 286 287 ret = jffs2_flash_read(c, ofs, len, &retlen, buf); 288 if (ret) { 289 D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n", len, ofs, ret)); 290 return ret; 291 } 292 if (retlen < len) { 293 D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n", ofs, retlen)); 294 return -EIO; 295 } 296 return 0; 297 } 298 299 int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb) 300 { 301 if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size 302 && (!jeb->first_node || !ref_next(jeb->first_node)) ) 303 return BLK_STATE_CLEANMARKER; 304 305 /* move blocks with max 4 byte dirty space to cleanlist */ 306 else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) { 307 c->dirty_size -= jeb->dirty_size; 308 c->wasted_size += jeb->dirty_size; 309 jeb->wasted_size += jeb->dirty_size; 310 jeb->dirty_size = 0; 311 return BLK_STATE_CLEAN; 312 } else if (jeb->used_size || jeb->unchecked_size) 313 return BLK_STATE_PARTDIRTY; 314 else 315 return BLK_STATE_ALLDIRTY; 316 } 317 318 #ifdef CONFIG_JFFS2_FS_XATTR 319 static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 320 struct jffs2_raw_xattr *rx, uint32_t ofs, 321 struct jffs2_summary *s) 322 { 323 struct jffs2_xattr_datum *xd; 324 uint32_t xid, version, totlen, crc; 325 int err; 326 327 crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4); 328 if (crc != je32_to_cpu(rx->node_crc)) { 329 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n", 330 ofs, je32_to_cpu(rx->node_crc), crc); 331 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen)))) 332 return err; 333 return 0; 334 } 335 336 xid = je32_to_cpu(rx->xid); 337 version = je32_to_cpu(rx->version); 338 339 totlen = PAD(sizeof(struct jffs2_raw_xattr) 340 + rx->name_len + 1 + je16_to_cpu(rx->value_len)); 341 if (totlen != je32_to_cpu(rx->totlen)) { 342 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n", 343 ofs, je32_to_cpu(rx->totlen), totlen); 344 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen)))) 345 return err; 346 return 0; 347 } 348 349 xd = jffs2_setup_xattr_datum(c, xid, version); 350 if (IS_ERR(xd)) 351 return PTR_ERR(xd); 352 353 if (xd->version > version) { 354 struct jffs2_raw_node_ref *raw 355 = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL); 356 raw->next_in_ino = xd->node->next_in_ino; 357 xd->node->next_in_ino = raw; 358 } else { 359 xd->version = version; 360 xd->xprefix = rx->xprefix; 361 xd->name_len = rx->name_len; 362 xd->value_len = je16_to_cpu(rx->value_len); 363 xd->data_crc = je32_to_cpu(rx->data_crc); 364 365 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd); 366 } 367 368 if (jffs2_sum_active()) 369 jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset); 370 dbg_xattr("scaning xdatum at %#08x (xid=%u, version=%u)\n", 371 ofs, xd->xid, xd->version); 372 return 0; 373 } 374 375 static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 376 struct jffs2_raw_xref *rr, uint32_t ofs, 377 struct jffs2_summary *s) 378 { 379 struct jffs2_xattr_ref *ref; 380 uint32_t crc; 381 int err; 382 383 crc = crc32(0, rr, sizeof(*rr) - 4); 384 if (crc != je32_to_cpu(rr->node_crc)) { 385 JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n", 386 ofs, je32_to_cpu(rr->node_crc), crc); 387 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen))))) 388 return err; 389 return 0; 390 } 391 392 if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) { 393 JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n", 394 ofs, je32_to_cpu(rr->totlen), 395 PAD(sizeof(struct jffs2_raw_xref))); 396 if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen)))) 397 return err; 398 return 0; 399 } 400 401 ref = jffs2_alloc_xattr_ref(); 402 if (!ref) 403 return -ENOMEM; 404 405 /* BEFORE jffs2_build_xattr_subsystem() called, 406 * and AFTER xattr_ref is marked as a dead xref, 407 * ref->xid is used to store 32bit xid, xd is not used 408 * ref->ino is used to store 32bit inode-number, ic is not used 409 * Thoes variables are declared as union, thus using those 410 * are exclusive. In a similar way, ref->next is temporarily 411 * used to chain all xattr_ref object. It's re-chained to 412 * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly. 413 */ 414 ref->ino = je32_to_cpu(rr->ino); 415 ref->xid = je32_to_cpu(rr->xid); 416 ref->xseqno = je32_to_cpu(rr->xseqno); 417 if (ref->xseqno > c->highest_xseqno) 418 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER); 419 ref->next = c->xref_temp; 420 c->xref_temp = ref; 421 422 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref); 423 424 if (jffs2_sum_active()) 425 jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset); 426 dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n", 427 ofs, ref->xid, ref->ino); 428 return 0; 429 } 430 #endif 431 432 /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into 433 the flash, XIP-style */ 434 static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 435 unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) { 436 struct jffs2_unknown_node *node; 437 struct jffs2_unknown_node crcnode; 438 uint32_t ofs, prevofs, max_ofs; 439 uint32_t hdr_crc, buf_ofs, buf_len; 440 int err; 441 int noise = 0; 442 443 444 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 445 int cleanmarkerfound = 0; 446 #endif 447 448 ofs = jeb->offset; 449 prevofs = jeb->offset - 1; 450 451 D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs)); 452 453 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 454 if (jffs2_cleanmarker_oob(c)) { 455 int ret; 456 457 if (c->mtd->block_isbad(c->mtd, jeb->offset)) 458 return BLK_STATE_BADBLOCK; 459 460 ret = jffs2_check_nand_cleanmarker(c, jeb); 461 D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret)); 462 463 /* Even if it's not found, we still scan to see 464 if the block is empty. We use this information 465 to decide whether to erase it or not. */ 466 switch (ret) { 467 case 0: cleanmarkerfound = 1; break; 468 case 1: break; 469 default: return ret; 470 } 471 } 472 #endif 473 474 if (jffs2_sum_active()) { 475 struct jffs2_sum_marker *sm; 476 void *sumptr = NULL; 477 uint32_t sumlen; 478 479 if (!buf_size) { 480 /* XIP case. Just look, point at the summary if it's there */ 481 sm = (void *)buf + c->sector_size - sizeof(*sm); 482 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) { 483 sumptr = buf + je32_to_cpu(sm->offset); 484 sumlen = c->sector_size - je32_to_cpu(sm->offset); 485 } 486 } else { 487 /* If NAND flash, read a whole page of it. Else just the end */ 488 if (c->wbuf_pagesize) 489 buf_len = c->wbuf_pagesize; 490 else 491 buf_len = sizeof(*sm); 492 493 /* Read as much as we want into the _end_ of the preallocated buffer */ 494 err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len, 495 jeb->offset + c->sector_size - buf_len, 496 buf_len); 497 if (err) 498 return err; 499 500 sm = (void *)buf + buf_size - sizeof(*sm); 501 if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) { 502 sumlen = c->sector_size - je32_to_cpu(sm->offset); 503 sumptr = buf + buf_size - sumlen; 504 505 /* Now, make sure the summary itself is available */ 506 if (sumlen > buf_size) { 507 /* Need to kmalloc for this. */ 508 sumptr = kmalloc(sumlen, GFP_KERNEL); 509 if (!sumptr) 510 return -ENOMEM; 511 memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len); 512 } 513 if (buf_len < sumlen) { 514 /* Need to read more so that the entire summary node is present */ 515 err = jffs2_fill_scan_buf(c, sumptr, 516 jeb->offset + c->sector_size - sumlen, 517 sumlen - buf_len); 518 if (err) 519 return err; 520 } 521 } 522 523 } 524 525 if (sumptr) { 526 err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random); 527 528 if (buf_size && sumlen > buf_size) 529 kfree(sumptr); 530 /* If it returns with a real error, bail. 531 If it returns positive, that's a block classification 532 (i.e. BLK_STATE_xxx) so return that too. 533 If it returns zero, fall through to full scan. */ 534 if (err) 535 return err; 536 } 537 } 538 539 buf_ofs = jeb->offset; 540 541 if (!buf_size) { 542 /* This is the XIP case -- we're reading _directly_ from the flash chip */ 543 buf_len = c->sector_size; 544 } else { 545 buf_len = EMPTY_SCAN_SIZE(c->sector_size); 546 err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len); 547 if (err) 548 return err; 549 } 550 551 /* We temporarily use 'ofs' as a pointer into the buffer/jeb */ 552 ofs = 0; 553 max_ofs = EMPTY_SCAN_SIZE(c->sector_size); 554 /* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */ 555 while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF) 556 ofs += 4; 557 558 if (ofs == max_ofs) { 559 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER 560 if (jffs2_cleanmarker_oob(c)) { 561 /* scan oob, take care of cleanmarker */ 562 int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound); 563 D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret)); 564 switch (ret) { 565 case 0: return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF; 566 case 1: return BLK_STATE_ALLDIRTY; 567 default: return ret; 568 } 569 } 570 #endif 571 D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset)); 572 if (c->cleanmarker_size == 0) 573 return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */ 574 else 575 return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */ 576 } 577 if (ofs) { 578 D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset, 579 jeb->offset + ofs)); 580 if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1))) 581 return err; 582 if ((err = jffs2_scan_dirty_space(c, jeb, ofs))) 583 return err; 584 } 585 586 /* Now ofs is a complete physical flash offset as it always was... */ 587 ofs += jeb->offset; 588 589 noise = 10; 590 591 dbg_summary("no summary found in jeb 0x%08x. Apply original scan.\n",jeb->offset); 592 593 scan_more: 594 while(ofs < jeb->offset + c->sector_size) { 595 596 jffs2_dbg_acct_paranoia_check_nolock(c, jeb); 597 598 /* Make sure there are node refs available for use */ 599 err = jffs2_prealloc_raw_node_refs(c, jeb, 2); 600 if (err) 601 return err; 602 603 cond_resched(); 604 605 if (ofs & 3) { 606 printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs); 607 ofs = PAD(ofs); 608 continue; 609 } 610 if (ofs == prevofs) { 611 printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs); 612 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 613 return err; 614 ofs += 4; 615 continue; 616 } 617 prevofs = ofs; 618 619 if (jeb->offset + c->sector_size < ofs + sizeof(*node)) { 620 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), 621 jeb->offset, c->sector_size, ofs, sizeof(*node))); 622 if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs))) 623 return err; 624 break; 625 } 626 627 if (buf_ofs + buf_len < ofs + sizeof(*node)) { 628 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 629 D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x\n", 630 sizeof(struct jffs2_unknown_node), buf_len, ofs)); 631 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 632 if (err) 633 return err; 634 buf_ofs = ofs; 635 } 636 637 node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs]; 638 639 if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) { 640 uint32_t inbuf_ofs; 641 uint32_t empty_start, scan_end; 642 643 empty_start = ofs; 644 ofs += 4; 645 scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len); 646 647 D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs)); 648 more_empty: 649 inbuf_ofs = ofs - buf_ofs; 650 while (inbuf_ofs < scan_end) { 651 if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) { 652 printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n", 653 empty_start, ofs); 654 if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start))) 655 return err; 656 goto scan_more; 657 } 658 659 inbuf_ofs+=4; 660 ofs += 4; 661 } 662 /* Ran off end. */ 663 D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs)); 664 665 /* If we're only checking the beginning of a block with a cleanmarker, 666 bail now */ 667 if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) && 668 c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) { 669 D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... assuming all clean\n", EMPTY_SCAN_SIZE(c->sector_size))); 670 return BLK_STATE_CLEANMARKER; 671 } 672 if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */ 673 scan_end = buf_len; 674 goto more_empty; 675 } 676 677 /* See how much more there is to read in this eraseblock... */ 678 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 679 if (!buf_len) { 680 /* No more to read. Break out of main loop without marking 681 this range of empty space as dirty (because it's not) */ 682 D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block. Treating as free_space\n", 683 empty_start)); 684 break; 685 } 686 /* point never reaches here */ 687 scan_end = buf_len; 688 D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs)); 689 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 690 if (err) 691 return err; 692 buf_ofs = ofs; 693 goto more_empty; 694 } 695 696 if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) { 697 printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?\n", ofs); 698 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 699 return err; 700 ofs += 4; 701 continue; 702 } 703 if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) { 704 D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs)); 705 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 706 return err; 707 ofs += 4; 708 continue; 709 } 710 if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) { 711 printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs); 712 printk(KERN_WARNING "You cannot use older JFFS2 filesystems with newer kernels\n"); 713 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 714 return err; 715 ofs += 4; 716 continue; 717 } 718 if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) { 719 /* OK. We're out of possibilities. Whinge and move on */ 720 noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead\n", 721 JFFS2_MAGIC_BITMASK, ofs, 722 je16_to_cpu(node->magic)); 723 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 724 return err; 725 ofs += 4; 726 continue; 727 } 728 /* We seem to have a node of sorts. Check the CRC */ 729 crcnode.magic = node->magic; 730 crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE); 731 crcnode.totlen = node->totlen; 732 hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4); 733 734 if (hdr_crc != je32_to_cpu(node->hdr_crc)) { 735 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", 736 ofs, je16_to_cpu(node->magic), 737 je16_to_cpu(node->nodetype), 738 je32_to_cpu(node->totlen), 739 je32_to_cpu(node->hdr_crc), 740 hdr_crc); 741 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 742 return err; 743 ofs += 4; 744 continue; 745 } 746 747 if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) { 748 /* Eep. Node goes over the end of the erase block. */ 749 printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run over the end of the erase block\n", 750 ofs, je32_to_cpu(node->totlen)); 751 printk(KERN_WARNING "Perhaps the file system was created with the wrong erase size?\n"); 752 if ((err = jffs2_scan_dirty_space(c, jeb, 4))) 753 return err; 754 ofs += 4; 755 continue; 756 } 757 758 if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) { 759 /* Wheee. This is an obsoleted node */ 760 D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs)); 761 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 762 return err; 763 ofs += PAD(je32_to_cpu(node->totlen)); 764 continue; 765 } 766 767 switch(je16_to_cpu(node->nodetype)) { 768 case JFFS2_NODETYPE_INODE: 769 if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) { 770 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 771 D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x\n", 772 sizeof(struct jffs2_raw_inode), buf_len, ofs)); 773 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 774 if (err) 775 return err; 776 buf_ofs = ofs; 777 node = (void *)buf; 778 } 779 err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s); 780 if (err) return err; 781 ofs += PAD(je32_to_cpu(node->totlen)); 782 break; 783 784 case JFFS2_NODETYPE_DIRENT: 785 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 786 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 787 D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x\n", 788 je32_to_cpu(node->totlen), buf_len, ofs)); 789 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 790 if (err) 791 return err; 792 buf_ofs = ofs; 793 node = (void *)buf; 794 } 795 err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s); 796 if (err) return err; 797 ofs += PAD(je32_to_cpu(node->totlen)); 798 break; 799 800 #ifdef CONFIG_JFFS2_FS_XATTR 801 case JFFS2_NODETYPE_XATTR: 802 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 803 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 804 D1(printk(KERN_DEBUG "Fewer than %d bytes (xattr node)" 805 " left to end of buf. Reading 0x%x at 0x%08x\n", 806 je32_to_cpu(node->totlen), buf_len, ofs)); 807 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 808 if (err) 809 return err; 810 buf_ofs = ofs; 811 node = (void *)buf; 812 } 813 err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s); 814 if (err) 815 return err; 816 ofs += PAD(je32_to_cpu(node->totlen)); 817 break; 818 case JFFS2_NODETYPE_XREF: 819 if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) { 820 buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs); 821 D1(printk(KERN_DEBUG "Fewer than %d bytes (xref node)" 822 " left to end of buf. Reading 0x%x at 0x%08x\n", 823 je32_to_cpu(node->totlen), buf_len, ofs)); 824 err = jffs2_fill_scan_buf(c, buf, ofs, buf_len); 825 if (err) 826 return err; 827 buf_ofs = ofs; 828 node = (void *)buf; 829 } 830 err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s); 831 if (err) 832 return err; 833 ofs += PAD(je32_to_cpu(node->totlen)); 834 break; 835 #endif /* CONFIG_JFFS2_FS_XATTR */ 836 837 case JFFS2_NODETYPE_CLEANMARKER: 838 D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs)); 839 if (je32_to_cpu(node->totlen) != c->cleanmarker_size) { 840 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x\n", 841 ofs, je32_to_cpu(node->totlen), c->cleanmarker_size); 842 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node))))) 843 return err; 844 ofs += PAD(sizeof(struct jffs2_unknown_node)); 845 } else if (jeb->first_node) { 846 printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)\n", ofs, jeb->offset); 847 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node))))) 848 return err; 849 ofs += PAD(sizeof(struct jffs2_unknown_node)); 850 } else { 851 jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL); 852 853 ofs += PAD(c->cleanmarker_size); 854 } 855 break; 856 857 case JFFS2_NODETYPE_PADDING: 858 if (jffs2_sum_active()) 859 jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen)); 860 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 861 return err; 862 ofs += PAD(je32_to_cpu(node->totlen)); 863 break; 864 865 default: 866 switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) { 867 case JFFS2_FEATURE_ROCOMPAT: 868 printk(KERN_NOTICE "Read-only compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs); 869 c->flags |= JFFS2_SB_FLAG_RO; 870 if (!(jffs2_is_readonly(c))) 871 return -EROFS; 872 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 873 return err; 874 ofs += PAD(je32_to_cpu(node->totlen)); 875 break; 876 877 case JFFS2_FEATURE_INCOMPAT: 878 printk(KERN_NOTICE "Incompatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs); 879 return -EINVAL; 880 881 case JFFS2_FEATURE_RWCOMPAT_DELETE: 882 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs)); 883 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen))))) 884 return err; 885 ofs += PAD(je32_to_cpu(node->totlen)); 886 break; 887 888 case JFFS2_FEATURE_RWCOMPAT_COPY: { 889 D1(printk(KERN_NOTICE "Unknown but compatible feature node (0x%04x) found at offset 0x%08x\n", je16_to_cpu(node->nodetype), ofs)); 890 891 jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL); 892 893 /* We can't summarise nodes we don't grok */ 894 jffs2_sum_disable_collecting(s); 895 ofs += PAD(je32_to_cpu(node->totlen)); 896 break; 897 } 898 } 899 } 900 } 901 902 if (jffs2_sum_active()) { 903 if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) { 904 dbg_summary("There is not enough space for " 905 "summary information, disabling for this jeb!\n"); 906 jffs2_sum_disable_collecting(s); 907 } 908 } 909 910 D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x\n", 911 jeb->offset,jeb->free_size, jeb->dirty_size, jeb->unchecked_size, jeb->used_size, jeb->wasted_size)); 912 913 /* mark_node_obsolete can add to wasted !! */ 914 if (jeb->wasted_size) { 915 jeb->dirty_size += jeb->wasted_size; 916 c->dirty_size += jeb->wasted_size; 917 c->wasted_size -= jeb->wasted_size; 918 jeb->wasted_size = 0; 919 } 920 921 return jffs2_scan_classify_jeb(c, jeb); 922 } 923 924 struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino) 925 { 926 struct jffs2_inode_cache *ic; 927 928 ic = jffs2_get_ino_cache(c, ino); 929 if (ic) 930 return ic; 931 932 if (ino > c->highest_ino) 933 c->highest_ino = ino; 934 935 ic = jffs2_alloc_inode_cache(); 936 if (!ic) { 937 printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of inode cache failed\n"); 938 return NULL; 939 } 940 memset(ic, 0, sizeof(*ic)); 941 942 ic->ino = ino; 943 ic->nodes = (void *)ic; 944 jffs2_add_ino_cache(c, ic); 945 if (ino == 1) 946 ic->pino_nlink = 1; 947 return ic; 948 } 949 950 static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 951 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s) 952 { 953 struct jffs2_inode_cache *ic; 954 uint32_t crc, ino = je32_to_cpu(ri->ino); 955 956 D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs)); 957 958 /* We do very little here now. Just check the ino# to which we should attribute 959 this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 960 we used to scan the flash once only, reading everything we want from it into 961 memory, then building all our in-core data structures and freeing the extra 962 information. Now we allow the first part of the mount to complete a lot quicker, 963 but we have to go _back_ to the flash in order to finish the CRC checking, etc. 964 Which means that the _full_ amount of time to get to proper write mode with GC 965 operational may actually be _longer_ than before. Sucks to be me. */ 966 967 /* Check the node CRC in any case. */ 968 crc = crc32(0, ri, sizeof(*ri)-8); 969 if (crc != je32_to_cpu(ri->node_crc)) { 970 printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on " 971 "node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 972 ofs, je32_to_cpu(ri->node_crc), crc); 973 /* 974 * We believe totlen because the CRC on the node 975 * _header_ was OK, just the node itself failed. 976 */ 977 return jffs2_scan_dirty_space(c, jeb, 978 PAD(je32_to_cpu(ri->totlen))); 979 } 980 981 ic = jffs2_get_ino_cache(c, ino); 982 if (!ic) { 983 ic = jffs2_scan_make_ino_cache(c, ino); 984 if (!ic) 985 return -ENOMEM; 986 } 987 988 /* Wheee. It worked */ 989 jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic); 990 991 D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n", 992 je32_to_cpu(ri->ino), je32_to_cpu(ri->version), 993 je32_to_cpu(ri->offset), 994 je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize))); 995 996 pseudo_random += je32_to_cpu(ri->version); 997 998 if (jffs2_sum_active()) { 999 jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset); 1000 } 1001 1002 return 0; 1003 } 1004 1005 static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 1006 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s) 1007 { 1008 struct jffs2_full_dirent *fd; 1009 struct jffs2_inode_cache *ic; 1010 uint32_t checkedlen; 1011 uint32_t crc; 1012 int err; 1013 1014 D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs)); 1015 1016 /* We don't get here unless the node is still valid, so we don't have to 1017 mask in the ACCURATE bit any more. */ 1018 crc = crc32(0, rd, sizeof(*rd)-8); 1019 1020 if (crc != je32_to_cpu(rd->node_crc)) { 1021 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 1022 ofs, je32_to_cpu(rd->node_crc), crc); 1023 /* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */ 1024 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen))))) 1025 return err; 1026 return 0; 1027 } 1028 1029 pseudo_random += je32_to_cpu(rd->version); 1030 1031 /* Should never happen. Did. (OLPC trac #4184)*/ 1032 checkedlen = strnlen(rd->name, rd->nsize); 1033 if (checkedlen < rd->nsize) { 1034 printk(KERN_ERR "Dirent at %08x has zeroes in name. Truncating to %d chars\n", 1035 ofs, checkedlen); 1036 } 1037 fd = jffs2_alloc_full_dirent(checkedlen+1); 1038 if (!fd) { 1039 return -ENOMEM; 1040 } 1041 memcpy(&fd->name, rd->name, checkedlen); 1042 fd->name[checkedlen] = 0; 1043 1044 crc = crc32(0, fd->name, rd->nsize); 1045 if (crc != je32_to_cpu(rd->name_crc)) { 1046 printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x\n", 1047 ofs, je32_to_cpu(rd->name_crc), crc); 1048 D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n", fd->name, je32_to_cpu(rd->ino))); 1049 jffs2_free_full_dirent(fd); 1050 /* FIXME: Why do we believe totlen? */ 1051 /* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */ 1052 if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen))))) 1053 return err; 1054 return 0; 1055 } 1056 ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino)); 1057 if (!ic) { 1058 jffs2_free_full_dirent(fd); 1059 return -ENOMEM; 1060 } 1061 1062 fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd), 1063 PAD(je32_to_cpu(rd->totlen)), ic); 1064 1065 fd->next = NULL; 1066 fd->version = je32_to_cpu(rd->version); 1067 fd->ino = je32_to_cpu(rd->ino); 1068 fd->nhash = full_name_hash(fd->name, checkedlen); 1069 fd->type = rd->type; 1070 jffs2_add_fd_to_list(c, fd, &ic->scan_dents); 1071 1072 if (jffs2_sum_active()) { 1073 jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset); 1074 } 1075 1076 return 0; 1077 } 1078 1079 static int count_list(struct list_head *l) 1080 { 1081 uint32_t count = 0; 1082 struct list_head *tmp; 1083 1084 list_for_each(tmp, l) { 1085 count++; 1086 } 1087 return count; 1088 } 1089 1090 /* Note: This breaks if list_empty(head). I don't care. You 1091 might, if you copy this code and use it elsewhere :) */ 1092 static void rotate_list(struct list_head *head, uint32_t count) 1093 { 1094 struct list_head *n = head->next; 1095 1096 list_del(head); 1097 while(count--) { 1098 n = n->next; 1099 } 1100 list_add(head, n); 1101 } 1102 1103 void jffs2_rotate_lists(struct jffs2_sb_info *c) 1104 { 1105 uint32_t x; 1106 uint32_t rotateby; 1107 1108 x = count_list(&c->clean_list); 1109 if (x) { 1110 rotateby = pseudo_random % x; 1111 rotate_list((&c->clean_list), rotateby); 1112 } 1113 1114 x = count_list(&c->very_dirty_list); 1115 if (x) { 1116 rotateby = pseudo_random % x; 1117 rotate_list((&c->very_dirty_list), rotateby); 1118 } 1119 1120 x = count_list(&c->dirty_list); 1121 if (x) { 1122 rotateby = pseudo_random % x; 1123 rotate_list((&c->dirty_list), rotateby); 1124 } 1125 1126 x = count_list(&c->erasable_list); 1127 if (x) { 1128 rotateby = pseudo_random % x; 1129 rotate_list((&c->erasable_list), rotateby); 1130 } 1131 1132 if (c->nr_erasing_blocks) { 1133 rotateby = pseudo_random % c->nr_erasing_blocks; 1134 rotate_list((&c->erase_pending_list), rotateby); 1135 } 1136 1137 if (c->nr_free_blocks) { 1138 rotateby = pseudo_random % c->nr_free_blocks; 1139 rotate_list((&c->free_list), rotateby); 1140 } 1141 } 1142