1 /* 2 * Copyright (c) International Business Machines Corp., 2006 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Author: Artem Bityutskiy (Битюцкий Артём) 19 */ 20 21 /* 22 * UBI attaching sub-system. 23 * 24 * This sub-system is responsible for attaching MTD devices and it also 25 * implements flash media scanning. 26 * 27 * The attaching information is represented by a &struct ubi_attach_info' 28 * object. Information about volumes is represented by &struct ubi_ainf_volume 29 * objects which are kept in volume RB-tree with root at the @volumes field. 30 * The RB-tree is indexed by the volume ID. 31 * 32 * Logical eraseblocks are represented by &struct ubi_ainf_peb objects. These 33 * objects are kept in per-volume RB-trees with the root at the corresponding 34 * &struct ubi_ainf_volume object. To put it differently, we keep an RB-tree of 35 * per-volume objects and each of these objects is the root of RB-tree of 36 * per-LEB objects. 37 * 38 * Corrupted physical eraseblocks are put to the @corr list, free physical 39 * eraseblocks are put to the @free list and the physical eraseblock to be 40 * erased are put to the @erase list. 41 * 42 * About corruptions 43 * ~~~~~~~~~~~~~~~~~ 44 * 45 * UBI protects EC and VID headers with CRC-32 checksums, so it can detect 46 * whether the headers are corrupted or not. Sometimes UBI also protects the 47 * data with CRC-32, e.g., when it executes the atomic LEB change operation, or 48 * when it moves the contents of a PEB for wear-leveling purposes. 49 * 50 * UBI tries to distinguish between 2 types of corruptions. 51 * 52 * 1. Corruptions caused by power cuts. These are expected corruptions and UBI 53 * tries to handle them gracefully, without printing too many warnings and 54 * error messages. The idea is that we do not lose important data in these 55 * cases - we may lose only the data which were being written to the media just 56 * before the power cut happened, and the upper layers (e.g., UBIFS) are 57 * supposed to handle such data losses (e.g., by using the FS journal). 58 * 59 * When UBI detects a corruption (CRC-32 mismatch) in a PEB, and it looks like 60 * the reason is a power cut, UBI puts this PEB to the @erase list, and all 61 * PEBs in the @erase list are scheduled for erasure later. 62 * 63 * 2. Unexpected corruptions which are not caused by power cuts. During 64 * attaching, such PEBs are put to the @corr list and UBI preserves them. 65 * Obviously, this lessens the amount of available PEBs, and if at some point 66 * UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly informs 67 * about such PEBs every time the MTD device is attached. 68 * 69 * However, it is difficult to reliably distinguish between these types of 70 * corruptions and UBI's strategy is as follows (in case of attaching by 71 * scanning). UBI assumes corruption type 2 if the VID header is corrupted and 72 * the data area does not contain all 0xFFs, and there were no bit-flips or 73 * integrity errors (e.g., ECC errors in case of NAND) while reading the data 74 * area. Otherwise UBI assumes corruption type 1. So the decision criteria 75 * are as follows. 76 * o If the data area contains only 0xFFs, there are no data, and it is safe 77 * to just erase this PEB - this is corruption type 1. 78 * o If the data area has bit-flips or data integrity errors (ECC errors on 79 * NAND), it is probably a PEB which was being erased when power cut 80 * happened, so this is corruption type 1. However, this is just a guess, 81 * which might be wrong. 82 * o Otherwise this is corruption type 2. 83 */ 84 85 #include <linux/err.h> 86 #include <linux/slab.h> 87 #include <linux/crc32.h> 88 #include <linux/math64.h> 89 #include <linux/random.h> 90 #include "ubi.h" 91 92 static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai); 93 94 /* Temporary variables used during scanning */ 95 static struct ubi_ec_hdr *ech; 96 static struct ubi_vid_hdr *vidh; 97 98 /** 99 * add_to_list - add physical eraseblock to a list. 100 * @ai: attaching information 101 * @pnum: physical eraseblock number to add 102 * @vol_id: the last used volume id for the PEB 103 * @lnum: the last used LEB number for the PEB 104 * @ec: erase counter of the physical eraseblock 105 * @to_head: if not zero, add to the head of the list 106 * @list: the list to add to 107 * 108 * This function allocates a 'struct ubi_ainf_peb' object for physical 109 * eraseblock @pnum and adds it to the "free", "erase", or "alien" lists. 110 * It stores the @lnum and @vol_id alongside, which can both be 111 * %UBI_UNKNOWN if they are not available, not readable, or not assigned. 112 * If @to_head is not zero, PEB will be added to the head of the list, which 113 * basically means it will be processed first later. E.g., we add corrupted 114 * PEBs (corrupted due to power cuts) to the head of the erase list to make 115 * sure we erase them first and get rid of corruptions ASAP. This function 116 * returns zero in case of success and a negative error code in case of 117 * failure. 118 */ 119 static int add_to_list(struct ubi_attach_info *ai, int pnum, int vol_id, 120 int lnum, int ec, int to_head, struct list_head *list) 121 { 122 struct ubi_ainf_peb *aeb; 123 124 if (list == &ai->free) { 125 dbg_bld("add to free: PEB %d, EC %d", pnum, ec); 126 } else if (list == &ai->erase) { 127 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec); 128 } else if (list == &ai->alien) { 129 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec); 130 ai->alien_peb_count += 1; 131 } else 132 BUG(); 133 134 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL); 135 if (!aeb) 136 return -ENOMEM; 137 138 aeb->pnum = pnum; 139 aeb->vol_id = vol_id; 140 aeb->lnum = lnum; 141 aeb->ec = ec; 142 if (to_head) 143 list_add(&aeb->u.list, list); 144 else 145 list_add_tail(&aeb->u.list, list); 146 return 0; 147 } 148 149 /** 150 * add_corrupted - add a corrupted physical eraseblock. 151 * @ai: attaching information 152 * @pnum: physical eraseblock number to add 153 * @ec: erase counter of the physical eraseblock 154 * 155 * This function allocates a 'struct ubi_ainf_peb' object for a corrupted 156 * physical eraseblock @pnum and adds it to the 'corr' list. The corruption 157 * was presumably not caused by a power cut. Returns zero in case of success 158 * and a negative error code in case of failure. 159 */ 160 static int add_corrupted(struct ubi_attach_info *ai, int pnum, int ec) 161 { 162 struct ubi_ainf_peb *aeb; 163 164 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec); 165 166 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL); 167 if (!aeb) 168 return -ENOMEM; 169 170 ai->corr_peb_count += 1; 171 aeb->pnum = pnum; 172 aeb->ec = ec; 173 list_add(&aeb->u.list, &ai->corr); 174 return 0; 175 } 176 177 /** 178 * validate_vid_hdr - check volume identifier header. 179 * @vid_hdr: the volume identifier header to check 180 * @av: information about the volume this logical eraseblock belongs to 181 * @pnum: physical eraseblock number the VID header came from 182 * 183 * This function checks that data stored in @vid_hdr is consistent. Returns 184 * non-zero if an inconsistency was found and zero if not. 185 * 186 * Note, UBI does sanity check of everything it reads from the flash media. 187 * Most of the checks are done in the I/O sub-system. Here we check that the 188 * information in the VID header is consistent to the information in other VID 189 * headers of the same volume. 190 */ 191 static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr, 192 const struct ubi_ainf_volume *av, int pnum) 193 { 194 int vol_type = vid_hdr->vol_type; 195 int vol_id = be32_to_cpu(vid_hdr->vol_id); 196 int used_ebs = be32_to_cpu(vid_hdr->used_ebs); 197 int data_pad = be32_to_cpu(vid_hdr->data_pad); 198 199 if (av->leb_count != 0) { 200 int av_vol_type; 201 202 /* 203 * This is not the first logical eraseblock belonging to this 204 * volume. Ensure that the data in its VID header is consistent 205 * to the data in previous logical eraseblock headers. 206 */ 207 208 if (vol_id != av->vol_id) { 209 ubi_err("inconsistent vol_id"); 210 goto bad; 211 } 212 213 if (av->vol_type == UBI_STATIC_VOLUME) 214 av_vol_type = UBI_VID_STATIC; 215 else 216 av_vol_type = UBI_VID_DYNAMIC; 217 218 if (vol_type != av_vol_type) { 219 ubi_err("inconsistent vol_type"); 220 goto bad; 221 } 222 223 if (used_ebs != av->used_ebs) { 224 ubi_err("inconsistent used_ebs"); 225 goto bad; 226 } 227 228 if (data_pad != av->data_pad) { 229 ubi_err("inconsistent data_pad"); 230 goto bad; 231 } 232 } 233 234 return 0; 235 236 bad: 237 ubi_err("inconsistent VID header at PEB %d", pnum); 238 ubi_dump_vid_hdr(vid_hdr); 239 ubi_dump_av(av); 240 return -EINVAL; 241 } 242 243 /** 244 * add_volume - add volume to the attaching information. 245 * @ai: attaching information 246 * @vol_id: ID of the volume to add 247 * @pnum: physical eraseblock number 248 * @vid_hdr: volume identifier header 249 * 250 * If the volume corresponding to the @vid_hdr logical eraseblock is already 251 * present in the attaching information, this function does nothing. Otherwise 252 * it adds corresponding volume to the attaching information. Returns a pointer 253 * to the allocated "av" object in case of success and a negative error code in 254 * case of failure. 255 */ 256 static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai, 257 int vol_id, int pnum, 258 const struct ubi_vid_hdr *vid_hdr) 259 { 260 struct ubi_ainf_volume *av; 261 struct rb_node **p = &ai->volumes.rb_node, *parent = NULL; 262 263 ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id)); 264 265 /* Walk the volume RB-tree to look if this volume is already present */ 266 while (*p) { 267 parent = *p; 268 av = rb_entry(parent, struct ubi_ainf_volume, rb); 269 270 if (vol_id == av->vol_id) 271 return av; 272 273 if (vol_id > av->vol_id) 274 p = &(*p)->rb_left; 275 else 276 p = &(*p)->rb_right; 277 } 278 279 /* The volume is absent - add it */ 280 av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL); 281 if (!av) 282 return ERR_PTR(-ENOMEM); 283 284 av->highest_lnum = av->leb_count = 0; 285 av->vol_id = vol_id; 286 av->root = RB_ROOT; 287 av->used_ebs = be32_to_cpu(vid_hdr->used_ebs); 288 av->data_pad = be32_to_cpu(vid_hdr->data_pad); 289 av->compat = vid_hdr->compat; 290 av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME 291 : UBI_STATIC_VOLUME; 292 if (vol_id > ai->highest_vol_id) 293 ai->highest_vol_id = vol_id; 294 295 rb_link_node(&av->rb, parent, p); 296 rb_insert_color(&av->rb, &ai->volumes); 297 ai->vols_found += 1; 298 dbg_bld("added volume %d", vol_id); 299 return av; 300 } 301 302 /** 303 * ubi_compare_lebs - find out which logical eraseblock is newer. 304 * @ubi: UBI device description object 305 * @aeb: first logical eraseblock to compare 306 * @pnum: physical eraseblock number of the second logical eraseblock to 307 * compare 308 * @vid_hdr: volume identifier header of the second logical eraseblock 309 * 310 * This function compares 2 copies of a LEB and informs which one is newer. In 311 * case of success this function returns a positive value, in case of failure, a 312 * negative error code is returned. The success return codes use the following 313 * bits: 314 * o bit 0 is cleared: the first PEB (described by @aeb) is newer than the 315 * second PEB (described by @pnum and @vid_hdr); 316 * o bit 0 is set: the second PEB is newer; 317 * o bit 1 is cleared: no bit-flips were detected in the newer LEB; 318 * o bit 1 is set: bit-flips were detected in the newer LEB; 319 * o bit 2 is cleared: the older LEB is not corrupted; 320 * o bit 2 is set: the older LEB is corrupted. 321 */ 322 int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb, 323 int pnum, const struct ubi_vid_hdr *vid_hdr) 324 { 325 void *buf; 326 int len, err, second_is_newer, bitflips = 0, corrupted = 0; 327 uint32_t data_crc, crc; 328 struct ubi_vid_hdr *vh = NULL; 329 unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum); 330 331 if (sqnum2 == aeb->sqnum) { 332 /* 333 * This must be a really ancient UBI image which has been 334 * created before sequence numbers support has been added. At 335 * that times we used 32-bit LEB versions stored in logical 336 * eraseblocks. That was before UBI got into mainline. We do not 337 * support these images anymore. Well, those images still work, 338 * but only if no unclean reboots happened. 339 */ 340 ubi_err("unsupported on-flash UBI format"); 341 return -EINVAL; 342 } 343 344 /* Obviously the LEB with lower sequence counter is older */ 345 second_is_newer = (sqnum2 > aeb->sqnum); 346 347 /* 348 * Now we know which copy is newer. If the copy flag of the PEB with 349 * newer version is not set, then we just return, otherwise we have to 350 * check data CRC. For the second PEB we already have the VID header, 351 * for the first one - we'll need to re-read it from flash. 352 * 353 * Note: this may be optimized so that we wouldn't read twice. 354 */ 355 356 if (second_is_newer) { 357 if (!vid_hdr->copy_flag) { 358 /* It is not a copy, so it is newer */ 359 dbg_bld("second PEB %d is newer, copy_flag is unset", 360 pnum); 361 return 1; 362 } 363 } else { 364 if (!aeb->copy_flag) { 365 /* It is not a copy, so it is newer */ 366 dbg_bld("first PEB %d is newer, copy_flag is unset", 367 pnum); 368 return bitflips << 1; 369 } 370 371 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); 372 if (!vh) 373 return -ENOMEM; 374 375 pnum = aeb->pnum; 376 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0); 377 if (err) { 378 if (err == UBI_IO_BITFLIPS) 379 bitflips = 1; 380 else { 381 ubi_err("VID of PEB %d header is bad, but it was OK earlier, err %d", 382 pnum, err); 383 if (err > 0) 384 err = -EIO; 385 386 goto out_free_vidh; 387 } 388 } 389 390 vid_hdr = vh; 391 } 392 393 /* Read the data of the copy and check the CRC */ 394 395 len = be32_to_cpu(vid_hdr->data_size); 396 buf = vmalloc(len); 397 if (!buf) { 398 err = -ENOMEM; 399 goto out_free_vidh; 400 } 401 402 err = ubi_io_read_data(ubi, buf, pnum, 0, len); 403 if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err)) 404 goto out_free_buf; 405 406 data_crc = be32_to_cpu(vid_hdr->data_crc); 407 crc = crc32(UBI_CRC32_INIT, buf, len); 408 if (crc != data_crc) { 409 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x", 410 pnum, crc, data_crc); 411 corrupted = 1; 412 bitflips = 0; 413 second_is_newer = !second_is_newer; 414 } else { 415 dbg_bld("PEB %d CRC is OK", pnum); 416 bitflips = !!err; 417 } 418 419 vfree(buf); 420 ubi_free_vid_hdr(ubi, vh); 421 422 if (second_is_newer) 423 dbg_bld("second PEB %d is newer, copy_flag is set", pnum); 424 else 425 dbg_bld("first PEB %d is newer, copy_flag is set", pnum); 426 427 return second_is_newer | (bitflips << 1) | (corrupted << 2); 428 429 out_free_buf: 430 vfree(buf); 431 out_free_vidh: 432 ubi_free_vid_hdr(ubi, vh); 433 return err; 434 } 435 436 /** 437 * ubi_add_to_av - add used physical eraseblock to the attaching information. 438 * @ubi: UBI device description object 439 * @ai: attaching information 440 * @pnum: the physical eraseblock number 441 * @ec: erase counter 442 * @vid_hdr: the volume identifier header 443 * @bitflips: if bit-flips were detected when this physical eraseblock was read 444 * 445 * This function adds information about a used physical eraseblock to the 446 * 'used' tree of the corresponding volume. The function is rather complex 447 * because it has to handle cases when this is not the first physical 448 * eraseblock belonging to the same logical eraseblock, and the newer one has 449 * to be picked, while the older one has to be dropped. This function returns 450 * zero in case of success and a negative error code in case of failure. 451 */ 452 int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum, 453 int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips) 454 { 455 int err, vol_id, lnum; 456 unsigned long long sqnum; 457 struct ubi_ainf_volume *av; 458 struct ubi_ainf_peb *aeb; 459 struct rb_node **p, *parent = NULL; 460 461 vol_id = be32_to_cpu(vid_hdr->vol_id); 462 lnum = be32_to_cpu(vid_hdr->lnum); 463 sqnum = be64_to_cpu(vid_hdr->sqnum); 464 465 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d", 466 pnum, vol_id, lnum, ec, sqnum, bitflips); 467 468 av = add_volume(ai, vol_id, pnum, vid_hdr); 469 if (IS_ERR(av)) 470 return PTR_ERR(av); 471 472 if (ai->max_sqnum < sqnum) 473 ai->max_sqnum = sqnum; 474 475 /* 476 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look 477 * if this is the first instance of this logical eraseblock or not. 478 */ 479 p = &av->root.rb_node; 480 while (*p) { 481 int cmp_res; 482 483 parent = *p; 484 aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb); 485 if (lnum != aeb->lnum) { 486 if (lnum < aeb->lnum) 487 p = &(*p)->rb_left; 488 else 489 p = &(*p)->rb_right; 490 continue; 491 } 492 493 /* 494 * There is already a physical eraseblock describing the same 495 * logical eraseblock present. 496 */ 497 498 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, EC %d", 499 aeb->pnum, aeb->sqnum, aeb->ec); 500 501 /* 502 * Make sure that the logical eraseblocks have different 503 * sequence numbers. Otherwise the image is bad. 504 * 505 * However, if the sequence number is zero, we assume it must 506 * be an ancient UBI image from the era when UBI did not have 507 * sequence numbers. We still can attach these images, unless 508 * there is a need to distinguish between old and new 509 * eraseblocks, in which case we'll refuse the image in 510 * 'ubi_compare_lebs()'. In other words, we attach old clean 511 * images, but refuse attaching old images with duplicated 512 * logical eraseblocks because there was an unclean reboot. 513 */ 514 if (aeb->sqnum == sqnum && sqnum != 0) { 515 ubi_err("two LEBs with same sequence number %llu", 516 sqnum); 517 ubi_dump_aeb(aeb, 0); 518 ubi_dump_vid_hdr(vid_hdr); 519 return -EINVAL; 520 } 521 522 /* 523 * Now we have to drop the older one and preserve the newer 524 * one. 525 */ 526 cmp_res = ubi_compare_lebs(ubi, aeb, pnum, vid_hdr); 527 if (cmp_res < 0) 528 return cmp_res; 529 530 if (cmp_res & 1) { 531 /* 532 * This logical eraseblock is newer than the one 533 * found earlier. 534 */ 535 err = validate_vid_hdr(vid_hdr, av, pnum); 536 if (err) 537 return err; 538 539 err = add_to_list(ai, aeb->pnum, aeb->vol_id, 540 aeb->lnum, aeb->ec, cmp_res & 4, 541 &ai->erase); 542 if (err) 543 return err; 544 545 aeb->ec = ec; 546 aeb->pnum = pnum; 547 aeb->vol_id = vol_id; 548 aeb->lnum = lnum; 549 aeb->scrub = ((cmp_res & 2) || bitflips); 550 aeb->copy_flag = vid_hdr->copy_flag; 551 aeb->sqnum = sqnum; 552 553 if (av->highest_lnum == lnum) 554 av->last_data_size = 555 be32_to_cpu(vid_hdr->data_size); 556 557 return 0; 558 } else { 559 /* 560 * This logical eraseblock is older than the one found 561 * previously. 562 */ 563 return add_to_list(ai, pnum, vol_id, lnum, ec, 564 cmp_res & 4, &ai->erase); 565 } 566 } 567 568 /* 569 * We've met this logical eraseblock for the first time, add it to the 570 * attaching information. 571 */ 572 573 err = validate_vid_hdr(vid_hdr, av, pnum); 574 if (err) 575 return err; 576 577 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL); 578 if (!aeb) 579 return -ENOMEM; 580 581 aeb->ec = ec; 582 aeb->pnum = pnum; 583 aeb->vol_id = vol_id; 584 aeb->lnum = lnum; 585 aeb->scrub = bitflips; 586 aeb->copy_flag = vid_hdr->copy_flag; 587 aeb->sqnum = sqnum; 588 589 if (av->highest_lnum <= lnum) { 590 av->highest_lnum = lnum; 591 av->last_data_size = be32_to_cpu(vid_hdr->data_size); 592 } 593 594 av->leb_count += 1; 595 rb_link_node(&aeb->u.rb, parent, p); 596 rb_insert_color(&aeb->u.rb, &av->root); 597 return 0; 598 } 599 600 /** 601 * ubi_find_av - find volume in the attaching information. 602 * @ai: attaching information 603 * @vol_id: the requested volume ID 604 * 605 * This function returns a pointer to the volume description or %NULL if there 606 * are no data about this volume in the attaching information. 607 */ 608 struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai, 609 int vol_id) 610 { 611 struct ubi_ainf_volume *av; 612 struct rb_node *p = ai->volumes.rb_node; 613 614 while (p) { 615 av = rb_entry(p, struct ubi_ainf_volume, rb); 616 617 if (vol_id == av->vol_id) 618 return av; 619 620 if (vol_id > av->vol_id) 621 p = p->rb_left; 622 else 623 p = p->rb_right; 624 } 625 626 return NULL; 627 } 628 629 /** 630 * ubi_remove_av - delete attaching information about a volume. 631 * @ai: attaching information 632 * @av: the volume attaching information to delete 633 */ 634 void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av) 635 { 636 struct rb_node *rb; 637 struct ubi_ainf_peb *aeb; 638 639 dbg_bld("remove attaching information about volume %d", av->vol_id); 640 641 while ((rb = rb_first(&av->root))) { 642 aeb = rb_entry(rb, struct ubi_ainf_peb, u.rb); 643 rb_erase(&aeb->u.rb, &av->root); 644 list_add_tail(&aeb->u.list, &ai->erase); 645 } 646 647 rb_erase(&av->rb, &ai->volumes); 648 kfree(av); 649 ai->vols_found -= 1; 650 } 651 652 /** 653 * early_erase_peb - erase a physical eraseblock. 654 * @ubi: UBI device description object 655 * @ai: attaching information 656 * @pnum: physical eraseblock number to erase; 657 * @ec: erase counter value to write (%UBI_UNKNOWN if it is unknown) 658 * 659 * This function erases physical eraseblock 'pnum', and writes the erase 660 * counter header to it. This function should only be used on UBI device 661 * initialization stages, when the EBA sub-system had not been yet initialized. 662 * This function returns zero in case of success and a negative error code in 663 * case of failure. 664 */ 665 static int early_erase_peb(struct ubi_device *ubi, 666 const struct ubi_attach_info *ai, int pnum, int ec) 667 { 668 int err; 669 struct ubi_ec_hdr *ec_hdr; 670 671 if ((long long)ec >= UBI_MAX_ERASECOUNTER) { 672 /* 673 * Erase counter overflow. Upgrade UBI and use 64-bit 674 * erase counters internally. 675 */ 676 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec); 677 return -EINVAL; 678 } 679 680 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); 681 if (!ec_hdr) 682 return -ENOMEM; 683 684 ec_hdr->ec = cpu_to_be64(ec); 685 686 err = ubi_io_sync_erase(ubi, pnum, 0); 687 if (err < 0) 688 goto out_free; 689 690 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr); 691 692 out_free: 693 kfree(ec_hdr); 694 return err; 695 } 696 697 /** 698 * ubi_early_get_peb - get a free physical eraseblock. 699 * @ubi: UBI device description object 700 * @ai: attaching information 701 * 702 * This function returns a free physical eraseblock. It is supposed to be 703 * called on the UBI initialization stages when the wear-leveling sub-system is 704 * not initialized yet. This function picks a physical eraseblocks from one of 705 * the lists, writes the EC header if it is needed, and removes it from the 706 * list. 707 * 708 * This function returns a pointer to the "aeb" of the found free PEB in case 709 * of success and an error code in case of failure. 710 */ 711 struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi, 712 struct ubi_attach_info *ai) 713 { 714 int err = 0; 715 struct ubi_ainf_peb *aeb, *tmp_aeb; 716 717 if (!list_empty(&ai->free)) { 718 aeb = list_entry(ai->free.next, struct ubi_ainf_peb, u.list); 719 list_del(&aeb->u.list); 720 dbg_bld("return free PEB %d, EC %d", aeb->pnum, aeb->ec); 721 return aeb; 722 } 723 724 /* 725 * We try to erase the first physical eraseblock from the erase list 726 * and pick it if we succeed, or try to erase the next one if not. And 727 * so forth. We don't want to take care about bad eraseblocks here - 728 * they'll be handled later. 729 */ 730 list_for_each_entry_safe(aeb, tmp_aeb, &ai->erase, u.list) { 731 if (aeb->ec == UBI_UNKNOWN) 732 aeb->ec = ai->mean_ec; 733 734 err = early_erase_peb(ubi, ai, aeb->pnum, aeb->ec+1); 735 if (err) 736 continue; 737 738 aeb->ec += 1; 739 list_del(&aeb->u.list); 740 dbg_bld("return PEB %d, EC %d", aeb->pnum, aeb->ec); 741 return aeb; 742 } 743 744 ubi_err("no free eraseblocks"); 745 return ERR_PTR(-ENOSPC); 746 } 747 748 /** 749 * check_corruption - check the data area of PEB. 750 * @ubi: UBI device description object 751 * @vid_hdr: the (corrupted) VID header of this PEB 752 * @pnum: the physical eraseblock number to check 753 * 754 * This is a helper function which is used to distinguish between VID header 755 * corruptions caused by power cuts and other reasons. If the PEB contains only 756 * 0xFF bytes in the data area, the VID header is most probably corrupted 757 * because of a power cut (%0 is returned in this case). Otherwise, it was 758 * probably corrupted for some other reasons (%1 is returned in this case). A 759 * negative error code is returned if a read error occurred. 760 * 761 * If the corruption reason was a power cut, UBI can safely erase this PEB. 762 * Otherwise, it should preserve it to avoid possibly destroying important 763 * information. 764 */ 765 static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr, 766 int pnum) 767 { 768 int err; 769 770 mutex_lock(&ubi->buf_mutex); 771 memset(ubi->peb_buf, 0x00, ubi->leb_size); 772 773 err = ubi_io_read(ubi, ubi->peb_buf, pnum, ubi->leb_start, 774 ubi->leb_size); 775 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) { 776 /* 777 * Bit-flips or integrity errors while reading the data area. 778 * It is difficult to say for sure what type of corruption is 779 * this, but presumably a power cut happened while this PEB was 780 * erased, so it became unstable and corrupted, and should be 781 * erased. 782 */ 783 err = 0; 784 goto out_unlock; 785 } 786 787 if (err) 788 goto out_unlock; 789 790 if (ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->leb_size)) 791 goto out_unlock; 792 793 ubi_err("PEB %d contains corrupted VID header, and the data does not contain all 0xFF", 794 pnum); 795 ubi_err("this may be a non-UBI PEB or a severe VID header corruption which requires manual inspection"); 796 ubi_dump_vid_hdr(vid_hdr); 797 pr_err("hexdump of PEB %d offset %d, length %d", 798 pnum, ubi->leb_start, ubi->leb_size); 799 ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, 800 ubi->peb_buf, ubi->leb_size, 1); 801 err = 1; 802 803 out_unlock: 804 mutex_unlock(&ubi->buf_mutex); 805 return err; 806 } 807 808 /** 809 * scan_peb - scan and process UBI headers of a PEB. 810 * @ubi: UBI device description object 811 * @ai: attaching information 812 * @pnum: the physical eraseblock number 813 * @vid: The volume ID of the found volume will be stored in this pointer 814 * @sqnum: The sqnum of the found volume will be stored in this pointer 815 * 816 * This function reads UBI headers of PEB @pnum, checks them, and adds 817 * information about this PEB to the corresponding list or RB-tree in the 818 * "attaching info" structure. Returns zero if the physical eraseblock was 819 * successfully handled and a negative error code in case of failure. 820 */ 821 static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai, 822 int pnum, int *vid, unsigned long long *sqnum) 823 { 824 long long uninitialized_var(ec); 825 int err, bitflips = 0, vol_id = -1, ec_err = 0; 826 827 dbg_bld("scan PEB %d", pnum); 828 829 /* Skip bad physical eraseblocks */ 830 err = ubi_io_is_bad(ubi, pnum); 831 if (err < 0) 832 return err; 833 else if (err) { 834 ai->bad_peb_count += 1; 835 return 0; 836 } 837 838 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0); 839 if (err < 0) 840 return err; 841 switch (err) { 842 case 0: 843 break; 844 case UBI_IO_BITFLIPS: 845 bitflips = 1; 846 break; 847 case UBI_IO_FF: 848 ai->empty_peb_count += 1; 849 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN, 850 UBI_UNKNOWN, 0, &ai->erase); 851 case UBI_IO_FF_BITFLIPS: 852 ai->empty_peb_count += 1; 853 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN, 854 UBI_UNKNOWN, 1, &ai->erase); 855 case UBI_IO_BAD_HDR_EBADMSG: 856 case UBI_IO_BAD_HDR: 857 /* 858 * We have to also look at the VID header, possibly it is not 859 * corrupted. Set %bitflips flag in order to make this PEB be 860 * moved and EC be re-created. 861 */ 862 ec_err = err; 863 ec = UBI_UNKNOWN; 864 bitflips = 1; 865 break; 866 default: 867 ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err); 868 return -EINVAL; 869 } 870 871 if (!ec_err) { 872 int image_seq; 873 874 /* Make sure UBI version is OK */ 875 if (ech->version != UBI_VERSION) { 876 ubi_err("this UBI version is %d, image version is %d", 877 UBI_VERSION, (int)ech->version); 878 return -EINVAL; 879 } 880 881 ec = be64_to_cpu(ech->ec); 882 if (ec > UBI_MAX_ERASECOUNTER) { 883 /* 884 * Erase counter overflow. The EC headers have 64 bits 885 * reserved, but we anyway make use of only 31 bit 886 * values, as this seems to be enough for any existing 887 * flash. Upgrade UBI and use 64-bit erase counters 888 * internally. 889 */ 890 ubi_err("erase counter overflow, max is %d", 891 UBI_MAX_ERASECOUNTER); 892 ubi_dump_ec_hdr(ech); 893 return -EINVAL; 894 } 895 896 /* 897 * Make sure that all PEBs have the same image sequence number. 898 * This allows us to detect situations when users flash UBI 899 * images incorrectly, so that the flash has the new UBI image 900 * and leftovers from the old one. This feature was added 901 * relatively recently, and the sequence number was always 902 * zero, because old UBI implementations always set it to zero. 903 * For this reasons, we do not panic if some PEBs have zero 904 * sequence number, while other PEBs have non-zero sequence 905 * number. 906 */ 907 image_seq = be32_to_cpu(ech->image_seq); 908 if (!ubi->image_seq && image_seq) 909 ubi->image_seq = image_seq; 910 if (ubi->image_seq && image_seq && 911 ubi->image_seq != image_seq) { 912 ubi_err("bad image sequence number %d in PEB %d, expected %d", 913 image_seq, pnum, ubi->image_seq); 914 ubi_dump_ec_hdr(ech); 915 return -EINVAL; 916 } 917 } 918 919 /* OK, we've done with the EC header, let's look at the VID header */ 920 921 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0); 922 if (err < 0) 923 return err; 924 switch (err) { 925 case 0: 926 break; 927 case UBI_IO_BITFLIPS: 928 bitflips = 1; 929 break; 930 case UBI_IO_BAD_HDR_EBADMSG: 931 if (ec_err == UBI_IO_BAD_HDR_EBADMSG) 932 /* 933 * Both EC and VID headers are corrupted and were read 934 * with data integrity error, probably this is a bad 935 * PEB, bit it is not marked as bad yet. This may also 936 * be a result of power cut during erasure. 937 */ 938 ai->maybe_bad_peb_count += 1; 939 case UBI_IO_BAD_HDR: 940 if (ec_err) 941 /* 942 * Both headers are corrupted. There is a possibility 943 * that this a valid UBI PEB which has corresponding 944 * LEB, but the headers are corrupted. However, it is 945 * impossible to distinguish it from a PEB which just 946 * contains garbage because of a power cut during erase 947 * operation. So we just schedule this PEB for erasure. 948 * 949 * Besides, in case of NOR flash, we deliberately 950 * corrupt both headers because NOR flash erasure is 951 * slow and can start from the end. 952 */ 953 err = 0; 954 else 955 /* 956 * The EC was OK, but the VID header is corrupted. We 957 * have to check what is in the data area. 958 */ 959 err = check_corruption(ubi, vidh, pnum); 960 961 if (err < 0) 962 return err; 963 else if (!err) 964 /* This corruption is caused by a power cut */ 965 err = add_to_list(ai, pnum, UBI_UNKNOWN, 966 UBI_UNKNOWN, ec, 1, &ai->erase); 967 else 968 /* This is an unexpected corruption */ 969 err = add_corrupted(ai, pnum, ec); 970 if (err) 971 return err; 972 goto adjust_mean_ec; 973 case UBI_IO_FF_BITFLIPS: 974 err = add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN, 975 ec, 1, &ai->erase); 976 if (err) 977 return err; 978 goto adjust_mean_ec; 979 case UBI_IO_FF: 980 if (ec_err || bitflips) 981 err = add_to_list(ai, pnum, UBI_UNKNOWN, 982 UBI_UNKNOWN, ec, 1, &ai->erase); 983 else 984 err = add_to_list(ai, pnum, UBI_UNKNOWN, 985 UBI_UNKNOWN, ec, 0, &ai->free); 986 if (err) 987 return err; 988 goto adjust_mean_ec; 989 default: 990 ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d", 991 err); 992 return -EINVAL; 993 } 994 995 vol_id = be32_to_cpu(vidh->vol_id); 996 if (vid) 997 *vid = vol_id; 998 if (sqnum) 999 *sqnum = be64_to_cpu(vidh->sqnum); 1000 if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) { 1001 int lnum = be32_to_cpu(vidh->lnum); 1002 1003 /* Unsupported internal volume */ 1004 switch (vidh->compat) { 1005 case UBI_COMPAT_DELETE: 1006 if (vol_id != UBI_FM_SB_VOLUME_ID 1007 && vol_id != UBI_FM_DATA_VOLUME_ID) { 1008 ubi_msg("\"delete\" compatible internal volume %d:%d found, will remove it", 1009 vol_id, lnum); 1010 } 1011 err = add_to_list(ai, pnum, vol_id, lnum, 1012 ec, 1, &ai->erase); 1013 if (err) 1014 return err; 1015 return 0; 1016 1017 case UBI_COMPAT_RO: 1018 ubi_msg("read-only compatible internal volume %d:%d found, switch to read-only mode", 1019 vol_id, lnum); 1020 ubi->ro_mode = 1; 1021 break; 1022 1023 case UBI_COMPAT_PRESERVE: 1024 ubi_msg("\"preserve\" compatible internal volume %d:%d found", 1025 vol_id, lnum); 1026 err = add_to_list(ai, pnum, vol_id, lnum, 1027 ec, 0, &ai->alien); 1028 if (err) 1029 return err; 1030 return 0; 1031 1032 case UBI_COMPAT_REJECT: 1033 ubi_err("incompatible internal volume %d:%d found", 1034 vol_id, lnum); 1035 return -EINVAL; 1036 } 1037 } 1038 1039 if (ec_err) 1040 ubi_warn("valid VID header but corrupted EC header at PEB %d", 1041 pnum); 1042 err = ubi_add_to_av(ubi, ai, pnum, ec, vidh, bitflips); 1043 if (err) 1044 return err; 1045 1046 adjust_mean_ec: 1047 if (!ec_err) { 1048 ai->ec_sum += ec; 1049 ai->ec_count += 1; 1050 if (ec > ai->max_ec) 1051 ai->max_ec = ec; 1052 if (ec < ai->min_ec) 1053 ai->min_ec = ec; 1054 } 1055 1056 return 0; 1057 } 1058 1059 /** 1060 * late_analysis - analyze the overall situation with PEB. 1061 * @ubi: UBI device description object 1062 * @ai: attaching information 1063 * 1064 * This is a helper function which takes a look what PEBs we have after we 1065 * gather information about all of them ("ai" is compete). It decides whether 1066 * the flash is empty and should be formatted of whether there are too many 1067 * corrupted PEBs and we should not attach this MTD device. Returns zero if we 1068 * should proceed with attaching the MTD device, and %-EINVAL if we should not. 1069 */ 1070 static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai) 1071 { 1072 struct ubi_ainf_peb *aeb; 1073 int max_corr, peb_count; 1074 1075 peb_count = ubi->peb_count - ai->bad_peb_count - ai->alien_peb_count; 1076 max_corr = peb_count / 20 ?: 8; 1077 1078 /* 1079 * Few corrupted PEBs is not a problem and may be just a result of 1080 * unclean reboots. However, many of them may indicate some problems 1081 * with the flash HW or driver. 1082 */ 1083 if (ai->corr_peb_count) { 1084 ubi_err("%d PEBs are corrupted and preserved", 1085 ai->corr_peb_count); 1086 pr_err("Corrupted PEBs are:"); 1087 list_for_each_entry(aeb, &ai->corr, u.list) 1088 pr_cont(" %d", aeb->pnum); 1089 pr_cont("\n"); 1090 1091 /* 1092 * If too many PEBs are corrupted, we refuse attaching, 1093 * otherwise, only print a warning. 1094 */ 1095 if (ai->corr_peb_count >= max_corr) { 1096 ubi_err("too many corrupted PEBs, refusing"); 1097 return -EINVAL; 1098 } 1099 } 1100 1101 if (ai->empty_peb_count + ai->maybe_bad_peb_count == peb_count) { 1102 /* 1103 * All PEBs are empty, or almost all - a couple PEBs look like 1104 * they may be bad PEBs which were not marked as bad yet. 1105 * 1106 * This piece of code basically tries to distinguish between 1107 * the following situations: 1108 * 1109 * 1. Flash is empty, but there are few bad PEBs, which are not 1110 * marked as bad so far, and which were read with error. We 1111 * want to go ahead and format this flash. While formatting, 1112 * the faulty PEBs will probably be marked as bad. 1113 * 1114 * 2. Flash contains non-UBI data and we do not want to format 1115 * it and destroy possibly important information. 1116 */ 1117 if (ai->maybe_bad_peb_count <= 2) { 1118 ai->is_empty = 1; 1119 ubi_msg("empty MTD device detected"); 1120 get_random_bytes(&ubi->image_seq, 1121 sizeof(ubi->image_seq)); 1122 } else { 1123 ubi_err("MTD device is not UBI-formatted and possibly contains non-UBI data - refusing it"); 1124 return -EINVAL; 1125 } 1126 1127 } 1128 1129 return 0; 1130 } 1131 1132 /** 1133 * destroy_av - free volume attaching information. 1134 * @av: volume attaching information 1135 * @ai: attaching information 1136 * 1137 * This function destroys the volume attaching information. 1138 */ 1139 static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av) 1140 { 1141 struct ubi_ainf_peb *aeb; 1142 struct rb_node *this = av->root.rb_node; 1143 1144 while (this) { 1145 if (this->rb_left) 1146 this = this->rb_left; 1147 else if (this->rb_right) 1148 this = this->rb_right; 1149 else { 1150 aeb = rb_entry(this, struct ubi_ainf_peb, u.rb); 1151 this = rb_parent(this); 1152 if (this) { 1153 if (this->rb_left == &aeb->u.rb) 1154 this->rb_left = NULL; 1155 else 1156 this->rb_right = NULL; 1157 } 1158 1159 kmem_cache_free(ai->aeb_slab_cache, aeb); 1160 } 1161 } 1162 kfree(av); 1163 } 1164 1165 /** 1166 * destroy_ai - destroy attaching information. 1167 * @ai: attaching information 1168 */ 1169 static void destroy_ai(struct ubi_attach_info *ai) 1170 { 1171 struct ubi_ainf_peb *aeb, *aeb_tmp; 1172 struct ubi_ainf_volume *av; 1173 struct rb_node *rb; 1174 1175 list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) { 1176 list_del(&aeb->u.list); 1177 kmem_cache_free(ai->aeb_slab_cache, aeb); 1178 } 1179 list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) { 1180 list_del(&aeb->u.list); 1181 kmem_cache_free(ai->aeb_slab_cache, aeb); 1182 } 1183 list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) { 1184 list_del(&aeb->u.list); 1185 kmem_cache_free(ai->aeb_slab_cache, aeb); 1186 } 1187 list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) { 1188 list_del(&aeb->u.list); 1189 kmem_cache_free(ai->aeb_slab_cache, aeb); 1190 } 1191 1192 /* Destroy the volume RB-tree */ 1193 rb = ai->volumes.rb_node; 1194 while (rb) { 1195 if (rb->rb_left) 1196 rb = rb->rb_left; 1197 else if (rb->rb_right) 1198 rb = rb->rb_right; 1199 else { 1200 av = rb_entry(rb, struct ubi_ainf_volume, rb); 1201 1202 rb = rb_parent(rb); 1203 if (rb) { 1204 if (rb->rb_left == &av->rb) 1205 rb->rb_left = NULL; 1206 else 1207 rb->rb_right = NULL; 1208 } 1209 1210 destroy_av(ai, av); 1211 } 1212 } 1213 1214 if (ai->aeb_slab_cache) 1215 kmem_cache_destroy(ai->aeb_slab_cache); 1216 1217 kfree(ai); 1218 } 1219 1220 /** 1221 * scan_all - scan entire MTD device. 1222 * @ubi: UBI device description object 1223 * @ai: attach info object 1224 * @start: start scanning at this PEB 1225 * 1226 * This function does full scanning of an MTD device and returns complete 1227 * information about it in form of a "struct ubi_attach_info" object. In case 1228 * of failure, an error code is returned. 1229 */ 1230 static int scan_all(struct ubi_device *ubi, struct ubi_attach_info *ai, 1231 int start) 1232 { 1233 int err, pnum; 1234 struct rb_node *rb1, *rb2; 1235 struct ubi_ainf_volume *av; 1236 struct ubi_ainf_peb *aeb; 1237 1238 err = -ENOMEM; 1239 1240 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); 1241 if (!ech) 1242 return err; 1243 1244 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); 1245 if (!vidh) 1246 goto out_ech; 1247 1248 for (pnum = start; pnum < ubi->peb_count; pnum++) { 1249 cond_resched(); 1250 1251 dbg_gen("process PEB %d", pnum); 1252 err = scan_peb(ubi, ai, pnum, NULL, NULL); 1253 if (err < 0) 1254 goto out_vidh; 1255 } 1256 1257 ubi_msg("scanning is finished"); 1258 1259 /* Calculate mean erase counter */ 1260 if (ai->ec_count) 1261 ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count); 1262 1263 err = late_analysis(ubi, ai); 1264 if (err) 1265 goto out_vidh; 1266 1267 /* 1268 * In case of unknown erase counter we use the mean erase counter 1269 * value. 1270 */ 1271 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { 1272 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) 1273 if (aeb->ec == UBI_UNKNOWN) 1274 aeb->ec = ai->mean_ec; 1275 } 1276 1277 list_for_each_entry(aeb, &ai->free, u.list) { 1278 if (aeb->ec == UBI_UNKNOWN) 1279 aeb->ec = ai->mean_ec; 1280 } 1281 1282 list_for_each_entry(aeb, &ai->corr, u.list) 1283 if (aeb->ec == UBI_UNKNOWN) 1284 aeb->ec = ai->mean_ec; 1285 1286 list_for_each_entry(aeb, &ai->erase, u.list) 1287 if (aeb->ec == UBI_UNKNOWN) 1288 aeb->ec = ai->mean_ec; 1289 1290 err = self_check_ai(ubi, ai); 1291 if (err) 1292 goto out_vidh; 1293 1294 ubi_free_vid_hdr(ubi, vidh); 1295 kfree(ech); 1296 1297 return 0; 1298 1299 out_vidh: 1300 ubi_free_vid_hdr(ubi, vidh); 1301 out_ech: 1302 kfree(ech); 1303 return err; 1304 } 1305 1306 #ifdef CONFIG_MTD_UBI_FASTMAP 1307 1308 /** 1309 * scan_fastmap - try to find a fastmap and attach from it. 1310 * @ubi: UBI device description object 1311 * @ai: attach info object 1312 * 1313 * Returns 0 on success, negative return values indicate an internal 1314 * error. 1315 * UBI_NO_FASTMAP denotes that no fastmap was found. 1316 * UBI_BAD_FASTMAP denotes that the found fastmap was invalid. 1317 */ 1318 static int scan_fast(struct ubi_device *ubi, struct ubi_attach_info *ai) 1319 { 1320 int err, pnum, fm_anchor = -1; 1321 unsigned long long max_sqnum = 0; 1322 1323 err = -ENOMEM; 1324 1325 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); 1326 if (!ech) 1327 goto out; 1328 1329 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); 1330 if (!vidh) 1331 goto out_ech; 1332 1333 for (pnum = 0; pnum < UBI_FM_MAX_START; pnum++) { 1334 int vol_id = -1; 1335 unsigned long long sqnum = -1; 1336 cond_resched(); 1337 1338 dbg_gen("process PEB %d", pnum); 1339 err = scan_peb(ubi, ai, pnum, &vol_id, &sqnum); 1340 if (err < 0) 1341 goto out_vidh; 1342 1343 if (vol_id == UBI_FM_SB_VOLUME_ID && sqnum > max_sqnum) { 1344 max_sqnum = sqnum; 1345 fm_anchor = pnum; 1346 } 1347 } 1348 1349 ubi_free_vid_hdr(ubi, vidh); 1350 kfree(ech); 1351 1352 if (fm_anchor < 0) 1353 return UBI_NO_FASTMAP; 1354 1355 return ubi_scan_fastmap(ubi, ai, fm_anchor); 1356 1357 out_vidh: 1358 ubi_free_vid_hdr(ubi, vidh); 1359 out_ech: 1360 kfree(ech); 1361 out: 1362 return err; 1363 } 1364 1365 #endif 1366 1367 static struct ubi_attach_info *alloc_ai(const char *slab_name) 1368 { 1369 struct ubi_attach_info *ai; 1370 1371 ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL); 1372 if (!ai) 1373 return ai; 1374 1375 INIT_LIST_HEAD(&ai->corr); 1376 INIT_LIST_HEAD(&ai->free); 1377 INIT_LIST_HEAD(&ai->erase); 1378 INIT_LIST_HEAD(&ai->alien); 1379 ai->volumes = RB_ROOT; 1380 ai->aeb_slab_cache = kmem_cache_create(slab_name, 1381 sizeof(struct ubi_ainf_peb), 1382 0, 0, NULL); 1383 if (!ai->aeb_slab_cache) { 1384 kfree(ai); 1385 ai = NULL; 1386 } 1387 1388 return ai; 1389 } 1390 1391 /** 1392 * ubi_attach - attach an MTD device. 1393 * @ubi: UBI device descriptor 1394 * @force_scan: if set to non-zero attach by scanning 1395 * 1396 * This function returns zero in case of success and a negative error code in 1397 * case of failure. 1398 */ 1399 int ubi_attach(struct ubi_device *ubi, int force_scan) 1400 { 1401 int err; 1402 struct ubi_attach_info *ai; 1403 1404 ai = alloc_ai("ubi_aeb_slab_cache"); 1405 if (!ai) 1406 return -ENOMEM; 1407 1408 #ifdef CONFIG_MTD_UBI_FASTMAP 1409 /* On small flash devices we disable fastmap in any case. */ 1410 if ((int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd) <= UBI_FM_MAX_START) { 1411 ubi->fm_disabled = 1; 1412 force_scan = 1; 1413 } 1414 1415 if (force_scan) 1416 err = scan_all(ubi, ai, 0); 1417 else { 1418 err = scan_fast(ubi, ai); 1419 if (err > 0) { 1420 if (err != UBI_NO_FASTMAP) { 1421 destroy_ai(ai); 1422 ai = alloc_ai("ubi_aeb_slab_cache2"); 1423 if (!ai) 1424 return -ENOMEM; 1425 } 1426 1427 err = scan_all(ubi, ai, UBI_FM_MAX_START); 1428 } 1429 } 1430 #else 1431 err = scan_all(ubi, ai, 0); 1432 #endif 1433 if (err) 1434 goto out_ai; 1435 1436 ubi->bad_peb_count = ai->bad_peb_count; 1437 ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count; 1438 ubi->corr_peb_count = ai->corr_peb_count; 1439 ubi->max_ec = ai->max_ec; 1440 ubi->mean_ec = ai->mean_ec; 1441 dbg_gen("max. sequence number: %llu", ai->max_sqnum); 1442 1443 err = ubi_read_volume_table(ubi, ai); 1444 if (err) 1445 goto out_ai; 1446 1447 err = ubi_wl_init(ubi, ai); 1448 if (err) 1449 goto out_vtbl; 1450 1451 err = ubi_eba_init(ubi, ai); 1452 if (err) 1453 goto out_wl; 1454 1455 #ifdef CONFIG_MTD_UBI_FASTMAP 1456 if (ubi->fm && ubi->dbg->chk_gen) { 1457 struct ubi_attach_info *scan_ai; 1458 1459 scan_ai = alloc_ai("ubi_ckh_aeb_slab_cache"); 1460 if (!scan_ai) 1461 goto out_wl; 1462 1463 err = scan_all(ubi, scan_ai, 0); 1464 if (err) { 1465 destroy_ai(scan_ai); 1466 goto out_wl; 1467 } 1468 1469 err = self_check_eba(ubi, ai, scan_ai); 1470 destroy_ai(scan_ai); 1471 1472 if (err) 1473 goto out_wl; 1474 } 1475 #endif 1476 1477 destroy_ai(ai); 1478 return 0; 1479 1480 out_wl: 1481 ubi_wl_close(ubi); 1482 out_vtbl: 1483 ubi_free_internal_volumes(ubi); 1484 vfree(ubi->vtbl); 1485 out_ai: 1486 destroy_ai(ai); 1487 return err; 1488 } 1489 1490 /** 1491 * self_check_ai - check the attaching information. 1492 * @ubi: UBI device description object 1493 * @ai: attaching information 1494 * 1495 * This function returns zero if the attaching information is all right, and a 1496 * negative error code if not or if an error occurred. 1497 */ 1498 static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai) 1499 { 1500 int pnum, err, vols_found = 0; 1501 struct rb_node *rb1, *rb2; 1502 struct ubi_ainf_volume *av; 1503 struct ubi_ainf_peb *aeb, *last_aeb; 1504 uint8_t *buf; 1505 1506 if (!ubi->dbg->chk_gen) 1507 return 0; 1508 1509 /* 1510 * At first, check that attaching information is OK. 1511 */ 1512 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { 1513 int leb_count = 0; 1514 1515 cond_resched(); 1516 1517 vols_found += 1; 1518 1519 if (ai->is_empty) { 1520 ubi_err("bad is_empty flag"); 1521 goto bad_av; 1522 } 1523 1524 if (av->vol_id < 0 || av->highest_lnum < 0 || 1525 av->leb_count < 0 || av->vol_type < 0 || av->used_ebs < 0 || 1526 av->data_pad < 0 || av->last_data_size < 0) { 1527 ubi_err("negative values"); 1528 goto bad_av; 1529 } 1530 1531 if (av->vol_id >= UBI_MAX_VOLUMES && 1532 av->vol_id < UBI_INTERNAL_VOL_START) { 1533 ubi_err("bad vol_id"); 1534 goto bad_av; 1535 } 1536 1537 if (av->vol_id > ai->highest_vol_id) { 1538 ubi_err("highest_vol_id is %d, but vol_id %d is there", 1539 ai->highest_vol_id, av->vol_id); 1540 goto out; 1541 } 1542 1543 if (av->vol_type != UBI_DYNAMIC_VOLUME && 1544 av->vol_type != UBI_STATIC_VOLUME) { 1545 ubi_err("bad vol_type"); 1546 goto bad_av; 1547 } 1548 1549 if (av->data_pad > ubi->leb_size / 2) { 1550 ubi_err("bad data_pad"); 1551 goto bad_av; 1552 } 1553 1554 last_aeb = NULL; 1555 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) { 1556 cond_resched(); 1557 1558 last_aeb = aeb; 1559 leb_count += 1; 1560 1561 if (aeb->pnum < 0 || aeb->ec < 0) { 1562 ubi_err("negative values"); 1563 goto bad_aeb; 1564 } 1565 1566 if (aeb->ec < ai->min_ec) { 1567 ubi_err("bad ai->min_ec (%d), %d found", 1568 ai->min_ec, aeb->ec); 1569 goto bad_aeb; 1570 } 1571 1572 if (aeb->ec > ai->max_ec) { 1573 ubi_err("bad ai->max_ec (%d), %d found", 1574 ai->max_ec, aeb->ec); 1575 goto bad_aeb; 1576 } 1577 1578 if (aeb->pnum >= ubi->peb_count) { 1579 ubi_err("too high PEB number %d, total PEBs %d", 1580 aeb->pnum, ubi->peb_count); 1581 goto bad_aeb; 1582 } 1583 1584 if (av->vol_type == UBI_STATIC_VOLUME) { 1585 if (aeb->lnum >= av->used_ebs) { 1586 ubi_err("bad lnum or used_ebs"); 1587 goto bad_aeb; 1588 } 1589 } else { 1590 if (av->used_ebs != 0) { 1591 ubi_err("non-zero used_ebs"); 1592 goto bad_aeb; 1593 } 1594 } 1595 1596 if (aeb->lnum > av->highest_lnum) { 1597 ubi_err("incorrect highest_lnum or lnum"); 1598 goto bad_aeb; 1599 } 1600 } 1601 1602 if (av->leb_count != leb_count) { 1603 ubi_err("bad leb_count, %d objects in the tree", 1604 leb_count); 1605 goto bad_av; 1606 } 1607 1608 if (!last_aeb) 1609 continue; 1610 1611 aeb = last_aeb; 1612 1613 if (aeb->lnum != av->highest_lnum) { 1614 ubi_err("bad highest_lnum"); 1615 goto bad_aeb; 1616 } 1617 } 1618 1619 if (vols_found != ai->vols_found) { 1620 ubi_err("bad ai->vols_found %d, should be %d", 1621 ai->vols_found, vols_found); 1622 goto out; 1623 } 1624 1625 /* Check that attaching information is correct */ 1626 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) { 1627 last_aeb = NULL; 1628 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) { 1629 int vol_type; 1630 1631 cond_resched(); 1632 1633 last_aeb = aeb; 1634 1635 err = ubi_io_read_vid_hdr(ubi, aeb->pnum, vidh, 1); 1636 if (err && err != UBI_IO_BITFLIPS) { 1637 ubi_err("VID header is not OK (%d)", err); 1638 if (err > 0) 1639 err = -EIO; 1640 return err; 1641 } 1642 1643 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ? 1644 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME; 1645 if (av->vol_type != vol_type) { 1646 ubi_err("bad vol_type"); 1647 goto bad_vid_hdr; 1648 } 1649 1650 if (aeb->sqnum != be64_to_cpu(vidh->sqnum)) { 1651 ubi_err("bad sqnum %llu", aeb->sqnum); 1652 goto bad_vid_hdr; 1653 } 1654 1655 if (av->vol_id != be32_to_cpu(vidh->vol_id)) { 1656 ubi_err("bad vol_id %d", av->vol_id); 1657 goto bad_vid_hdr; 1658 } 1659 1660 if (av->compat != vidh->compat) { 1661 ubi_err("bad compat %d", vidh->compat); 1662 goto bad_vid_hdr; 1663 } 1664 1665 if (aeb->lnum != be32_to_cpu(vidh->lnum)) { 1666 ubi_err("bad lnum %d", aeb->lnum); 1667 goto bad_vid_hdr; 1668 } 1669 1670 if (av->used_ebs != be32_to_cpu(vidh->used_ebs)) { 1671 ubi_err("bad used_ebs %d", av->used_ebs); 1672 goto bad_vid_hdr; 1673 } 1674 1675 if (av->data_pad != be32_to_cpu(vidh->data_pad)) { 1676 ubi_err("bad data_pad %d", av->data_pad); 1677 goto bad_vid_hdr; 1678 } 1679 } 1680 1681 if (!last_aeb) 1682 continue; 1683 1684 if (av->highest_lnum != be32_to_cpu(vidh->lnum)) { 1685 ubi_err("bad highest_lnum %d", av->highest_lnum); 1686 goto bad_vid_hdr; 1687 } 1688 1689 if (av->last_data_size != be32_to_cpu(vidh->data_size)) { 1690 ubi_err("bad last_data_size %d", av->last_data_size); 1691 goto bad_vid_hdr; 1692 } 1693 } 1694 1695 /* 1696 * Make sure that all the physical eraseblocks are in one of the lists 1697 * or trees. 1698 */ 1699 buf = kzalloc(ubi->peb_count, GFP_KERNEL); 1700 if (!buf) 1701 return -ENOMEM; 1702 1703 for (pnum = 0; pnum < ubi->peb_count; pnum++) { 1704 err = ubi_io_is_bad(ubi, pnum); 1705 if (err < 0) { 1706 kfree(buf); 1707 return err; 1708 } else if (err) 1709 buf[pnum] = 1; 1710 } 1711 1712 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) 1713 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) 1714 buf[aeb->pnum] = 1; 1715 1716 list_for_each_entry(aeb, &ai->free, u.list) 1717 buf[aeb->pnum] = 1; 1718 1719 list_for_each_entry(aeb, &ai->corr, u.list) 1720 buf[aeb->pnum] = 1; 1721 1722 list_for_each_entry(aeb, &ai->erase, u.list) 1723 buf[aeb->pnum] = 1; 1724 1725 list_for_each_entry(aeb, &ai->alien, u.list) 1726 buf[aeb->pnum] = 1; 1727 1728 err = 0; 1729 for (pnum = 0; pnum < ubi->peb_count; pnum++) 1730 if (!buf[pnum]) { 1731 ubi_err("PEB %d is not referred", pnum); 1732 err = 1; 1733 } 1734 1735 kfree(buf); 1736 if (err) 1737 goto out; 1738 return 0; 1739 1740 bad_aeb: 1741 ubi_err("bad attaching information about LEB %d", aeb->lnum); 1742 ubi_dump_aeb(aeb, 0); 1743 ubi_dump_av(av); 1744 goto out; 1745 1746 bad_av: 1747 ubi_err("bad attaching information about volume %d", av->vol_id); 1748 ubi_dump_av(av); 1749 goto out; 1750 1751 bad_vid_hdr: 1752 ubi_err("bad attaching information about volume %d", av->vol_id); 1753 ubi_dump_av(av); 1754 ubi_dump_vid_hdr(vidh); 1755 1756 out: 1757 dump_stack(); 1758 return -EINVAL; 1759 } 1760