yaffs_yaffs2.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2010 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include "yaffs_guts.h"
  15 #include "yaffs_trace.h"
  16 #include "yaffs_yaffs2.h"
  17 #include "yaffs_checkptrw.h"
  18 #include "yaffs_bitmap.h"
  19 #include "yaffs_nand.h"
  20 #include "yaffs_getblockinfo.h"
  21 #include "yaffs_verify.h"
  22 #include "yaffs_attribs.h"
  23
  24 /*
  25  * Checkpoints are really no benefit on very small partitions.
  26  *
  27  * To save space on small partitions don't bother with checkpoints unless
  28  * the partition is at least this big.
  29  */
  30 #define YAFFS_CHECKPOINT_MIN_BLOCKS 60
  31
  32 #define YAFFS_SMALL_HOLE_THRESHOLD 4
  33
  34 /*
  35  * Oldest Dirty Sequence Number handling.
  36  */
  37
  38 /* yaffs_calc_oldest_dirty_seq()
  39  * yaffs2_find_oldest_dirty_seq()
  40  * Calculate the oldest dirty sequence number if we don't know it.
  41  */
  42 void yaffs_calc_oldest_dirty_seq(struct yaffs_dev *dev)
  43 {
  44         int i;
  45         unsigned seq;
  46         unsigned block_no = 0;
  47         struct yaffs_block_info *b;
  48
  49         if (!dev->param.is_yaffs2)
  50                 return;
  51
  52         /* Find the oldest dirty sequence number. */
  53         seq = dev->seq_number + 1;
  54         b = dev->block_info;
  55         for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
  56                 if (b->block_state == YAFFS_BLOCK_STATE_FULL &&
  57                     (b->pages_in_use - b->soft_del_pages) <
  58                     dev->param.chunks_per_block && b->seq_number < seq) {
  59                         seq = b->seq_number;
  60                         block_no = i;
  61                 }
  62                 b++;
  63         }
  64
  65         if (block_no) {
  66                 dev->oldest_dirty_seq = seq;
  67                 dev->oldest_dirty_block = block_no;
  68         }
  69
  70 }
  71
  72 void yaffs2_find_oldest_dirty_seq(struct yaffs_dev *dev)
  73 {
  74         if (!dev->param.is_yaffs2)
  75                 return;
  76
  77         if (!dev->oldest_dirty_seq)
  78                 yaffs_calc_oldest_dirty_seq(dev);
  79 }
  80
  81 /*
  82  * yaffs_clear_oldest_dirty_seq()
  83  * Called when a block is erased or marked bad. (ie. when its seq_number
  84  * becomes invalid). If the value matches the oldest then we clear
  85  * dev->oldest_dirty_seq to force its recomputation.
  86  */
  87 void yaffs2_clear_oldest_dirty_seq(struct yaffs_dev *dev,
  88                                    struct yaffs_block_info *bi)
  89 {
  90
  91         if (!dev->param.is_yaffs2)
  92                 return;
  93
  94         if (!bi || bi->seq_number == dev->oldest_dirty_seq) {
  95                 dev->oldest_dirty_seq = 0;
  96                 dev->oldest_dirty_block = 0;
  97         }
  98 }
  99
 100 /*
 101  * yaffs2_update_oldest_dirty_seq()
 102  * Update the oldest dirty sequence number whenever we dirty a block.
 103  * Only do this if the oldest_dirty_seq is actually being tracked.
 104  */
 105 void yaffs2_update_oldest_dirty_seq(struct yaffs_dev *dev, unsigned block_no,
 106                                     struct yaffs_block_info *bi)
 107 {
 108         if (!dev->param.is_yaffs2)
 109                 return;
 110
 111         if (dev->oldest_dirty_seq) {
 112                 if (dev->oldest_dirty_seq > bi->seq_number) {
 113                         dev->oldest_dirty_seq = bi->seq_number;
 114                         dev->oldest_dirty_block = block_no;
 115                 }
 116         }
 117 }
 118
 119 int yaffs_block_ok_for_gc(struct yaffs_dev *dev, struct yaffs_block_info *bi)
 120 {
 121
 122         if (!dev->param.is_yaffs2)
 123                 return 1;       /* disqualification only applies to yaffs2. */
 124
 125         if (!bi->has_shrink_hdr)
 126                 return 1;       /* can gc */
 127
 128         yaffs2_find_oldest_dirty_seq(dev);
 129
 130         /* Can't do gc of this block if there are any blocks older than this one that have
 131          * discarded pages.
 132          */
 133         return (bi->seq_number <= dev->oldest_dirty_seq);
 134 }
 135
 136 /*
 137  * yaffs2_find_refresh_block()
 138  * periodically finds the oldest full block by sequence number for refreshing.
 139  * Only for yaffs2.
 140  */
 141 u32 yaffs2_find_refresh_block(struct yaffs_dev * dev)
 142 {
 143         u32 b;
 144
 145         u32 oldest = 0;
 146         u32 oldest_seq = 0;
 147
 148         struct yaffs_block_info *bi;
 149
 150         if (!dev->param.is_yaffs2)
 151                 return oldest;
 152
 153         /*
 154          * If refresh period < 10 then refreshing is disabled.
 155          */
 156         if (dev->param.refresh_period < 10)
 157                 return oldest;
 158
 159         /*
 160          * Fix broken values.
 161          */
 162         if (dev->refresh_skip > dev->param.refresh_period)
 163                 dev->refresh_skip = dev->param.refresh_period;
 164
 165         if (dev->refresh_skip > 0)
 166                 return oldest;
 167
 168         /*
 169          * Refresh skip is now zero.
 170          * We'll do a refresh this time around....
 171          * Update the refresh skip and find the oldest block.
 172          */
 173         dev->refresh_skip = dev->param.refresh_period;
 174         dev->refresh_count++;
 175         bi = dev->block_info;
 176         for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
 177
 178                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL) {
 179
 180                         if (oldest < 1 || bi->seq_number < oldest_seq) {
 181                                 oldest = b;
 182                                 oldest_seq = bi->seq_number;
 183                         }
 184                 }
 185                 bi++;
 186         }
 187
 188         if (oldest > 0) {
 189                 yaffs_trace(YAFFS_TRACE_GC,
 190                         "GC refresh count %d selected block %d with seq_number %d",
 191                         dev->refresh_count, oldest, oldest_seq);
 192         }
 193
 194         return oldest;
 195 }
 196
 197 int yaffs2_checkpt_required(struct yaffs_dev *dev)
 198 {
 199         int nblocks;
 200
 201         if (!dev->param.is_yaffs2)
 202                 return 0;
 203
 204         nblocks = dev->internal_end_block - dev->internal_start_block + 1;
 205
 206         return !dev->param.skip_checkpt_wr &&
 207             !dev->read_only && (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
 208 }
 209
 210 int yaffs_calc_checkpt_blocks_required(struct yaffs_dev *dev)
 211 {
 212         int retval;
 213
 214         if (!dev->param.is_yaffs2)
 215                 return 0;
 216
 217         if (!dev->checkpoint_blocks_required && yaffs2_checkpt_required(dev)) {
 218                 /* Not a valid value so recalculate */
 219                 int n_bytes = 0;
 220                 int n_blocks;
 221                 int dev_blocks =
 222                     (dev->param.end_block - dev->param.start_block + 1);
 223
 224                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 225                 n_bytes += sizeof(struct yaffs_checkpt_dev);
 226                 n_bytes += dev_blocks * sizeof(struct yaffs_block_info);
 227                 n_bytes += dev_blocks * dev->chunk_bit_stride;
 228                 n_bytes +=
 229                     (sizeof(struct yaffs_checkpt_obj) +
 230                      sizeof(u32)) * (dev->n_obj);
 231                 n_bytes += (dev->tnode_size + sizeof(u32)) * (dev->n_tnodes);
 232                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 233                 n_bytes += sizeof(u32); /* checksum */
 234
 235                 /* Round up and add 2 blocks to allow for some bad blocks, so add 3 */
 236
 237                 n_blocks =
 238                     (n_bytes /
 239                      (dev->data_bytes_per_chunk *
 240                       dev->param.chunks_per_block)) + 3;
 241
 242                 dev->checkpoint_blocks_required = n_blocks;
 243         }
 244
 245         retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
 246         if (retval < 0)
 247                 retval = 0;
 248         return retval;
 249 }
 250
 251 /*--------------------- Checkpointing --------------------*/
 252
 253 static int yaffs2_wr_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 254 {
 255         struct yaffs_checkpt_validity cp;
 256
 257         memset(&cp, 0, sizeof(cp));
 258
 259         cp.struct_type = sizeof(cp);
 260         cp.magic = YAFFS_MAGIC;
 261         cp.version = YAFFS_CHECKPOINT_VERSION;
 262         cp.head = (head) ? 1 : 0;
 263
 264         return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ? 1 : 0;
 265 }
 266
 267 static int yaffs2_rd_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 268 {
 269         struct yaffs_checkpt_validity cp;
 270         int ok;
 271
 272         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 273
 274         if (ok)
 275                 ok = (cp.struct_type == sizeof(cp)) &&
 276                     (cp.magic == YAFFS_MAGIC) &&
 277                     (cp.version == YAFFS_CHECKPOINT_VERSION) &&
 278                     (cp.head == ((head) ? 1 : 0));
 279         return ok ? 1 : 0;
 280 }
 281
 282 static void yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev *cp,
 283                                       struct yaffs_dev *dev)
 284 {
 285         cp->n_erased_blocks = dev->n_erased_blocks;
 286         cp->alloc_block = dev->alloc_block;
 287         cp->alloc_page = dev->alloc_page;
 288         cp->n_free_chunks = dev->n_free_chunks;
 289
 290         cp->n_deleted_files = dev->n_deleted_files;
 291         cp->n_unlinked_files = dev->n_unlinked_files;
 292         cp->n_bg_deletions = dev->n_bg_deletions;
 293         cp->seq_number = dev->seq_number;
 294
 295 }
 296
 297 static void yaffs_checkpt_dev_to_dev(struct yaffs_dev *dev,
 298                                      struct yaffs_checkpt_dev *cp)
 299 {
 300         dev->n_erased_blocks = cp->n_erased_blocks;
 301         dev->alloc_block = cp->alloc_block;
 302         dev->alloc_page = cp->alloc_page;
 303         dev->n_free_chunks = cp->n_free_chunks;
 304
 305         dev->n_deleted_files = cp->n_deleted_files;
 306         dev->n_unlinked_files = cp->n_unlinked_files;
 307         dev->n_bg_deletions = cp->n_bg_deletions;
 308         dev->seq_number = cp->seq_number;
 309 }
 310
 311 static int yaffs2_wr_checkpt_dev(struct yaffs_dev *dev)
 312 {
 313         struct yaffs_checkpt_dev cp;
 314         u32 n_bytes;
 315         u32 n_blocks =
 316             (dev->internal_end_block - dev->internal_start_block + 1);
 317
 318         int ok;
 319
 320         /* Write device runtime values */
 321         yaffs2_dev_to_checkpt_dev(&cp, dev);
 322         cp.struct_type = sizeof(cp);
 323
 324         ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 325
 326         /* Write block info */
 327         if (ok) {
 328                 n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 329                 ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) ==
 330                       n_bytes);
 331         }
 332
 333         /* Write chunk bits */
 334         if (ok) {
 335                 n_bytes = n_blocks * dev->chunk_bit_stride;
 336                 ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) ==
 337                       n_bytes);
 338         }
 339         return ok ? 1 : 0;
 340
 341 }
 342
 343 static int yaffs2_rd_checkpt_dev(struct yaffs_dev *dev)
 344 {
 345         struct yaffs_checkpt_dev cp;
 346         u32 n_bytes;
 347         u32 n_blocks =
 348             (dev->internal_end_block - dev->internal_start_block + 1);
 349
 350         int ok;
 351
 352         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 353         if (!ok)
 354                 return 0;
 355
 356         if (cp.struct_type != sizeof(cp))
 357                 return 0;
 358
 359         yaffs_checkpt_dev_to_dev(dev, &cp);
 360
 361         n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 362
 363         ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
 364
 365         if (!ok)
 366                 return 0;
 367         n_bytes = n_blocks * dev->chunk_bit_stride;
 368
 369         ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
 370
 371         return ok ? 1 : 0;
 372 }
 373
 374 static void yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj *cp,
 375                                    struct yaffs_obj *obj)
 376 {
 377
 378         cp->obj_id = obj->obj_id;
 379         cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
 380         cp->hdr_chunk = obj->hdr_chunk;
 381         cp->variant_type = obj->variant_type;
 382         cp->deleted = obj->deleted;
 383         cp->soft_del = obj->soft_del;
 384         cp->unlinked = obj->unlinked;
 385         cp->fake = obj->fake;
 386         cp->rename_allowed = obj->rename_allowed;
 387         cp->unlink_allowed = obj->unlink_allowed;
 388         cp->serial = obj->serial;
 389         cp->n_data_chunks = obj->n_data_chunks;
 390
 391         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 392                 cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
 393         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 394                 cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
 395 }
 396
 397 static int taffs2_checkpt_obj_to_obj(struct yaffs_obj *obj,
 398                                      struct yaffs_checkpt_obj *cp)
 399 {
 400
 401         struct yaffs_obj *parent;
 402
 403         if (obj->variant_type != cp->variant_type) {
 404                 yaffs_trace(YAFFS_TRACE_ERROR,
 405                         "Checkpoint read object %d type %d chunk %d does not match existing object type %d",
 406                         cp->obj_id, cp->variant_type, cp->hdr_chunk,
 407                         obj->variant_type);
 408                 return 0;
 409         }
 410
 411         obj->obj_id = cp->obj_id;
 412
 413         if (cp->parent_id)
 414                 parent = yaffs_find_or_create_by_number(obj->my_dev,
 415                                                         cp->parent_id,
 416                                                         YAFFS_OBJECT_TYPE_DIRECTORY);
 417         else
 418                 parent = NULL;
 419
 420         if (parent) {
 421                 if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
 422                         yaffs_trace(YAFFS_TRACE_ALWAYS,
 423                                 "Checkpoint read object %d parent %d type %d chunk %d Parent type, %d, not directory",
 424                                 cp->obj_id, cp->parent_id,
 425                                 cp->variant_type, cp->hdr_chunk,
 426                                 parent->variant_type);
 427                         return 0;
 428                 }
 429                 yaffs_add_obj_to_dir(parent, obj);
 430         }
 431
 432         obj->hdr_chunk = cp->hdr_chunk;
 433         obj->variant_type = cp->variant_type;
 434         obj->deleted = cp->deleted;
 435         obj->soft_del = cp->soft_del;
 436         obj->unlinked = cp->unlinked;
 437         obj->fake = cp->fake;
 438         obj->rename_allowed = cp->rename_allowed;
 439         obj->unlink_allowed = cp->unlink_allowed;
 440         obj->serial = cp->serial;
 441         obj->n_data_chunks = cp->n_data_chunks;
 442
 443         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 444                 obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
 445         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 446                 obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
 447
 448         if (obj->hdr_chunk > 0)
 449                 obj->lazy_loaded = 1;
 450         return 1;
 451 }
 452
 453 static int yaffs2_checkpt_tnode_worker(struct yaffs_obj *in,
 454                                        struct yaffs_tnode *tn, u32 level,
 455                                        int chunk_offset)
 456 {
 457         int i;
 458         struct yaffs_dev *dev = in->my_dev;
 459         int ok = 1;
 460
 461         if (tn) {
 462                 if (level > 0) {
 463
 464                         for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
 465                                 if (tn->internal[i]) {
 466                                         ok = yaffs2_checkpt_tnode_worker(in,
 467                                                                          tn->
 468                                                                          internal
 469                                                                          [i],
 470                                                                          level -
 471                                                                          1,
 472                                                                          (chunk_offset
 473                                                                           <<
 474                                                                           YAFFS_TNODES_INTERNAL_BITS)
 475                                                                          + i);
 476                                 }
 477                         }
 478                 } else if (level == 0) {
 479                         u32 base_offset =
 480                             chunk_offset << YAFFS_TNODES_LEVEL0_BITS;
 481                         ok = (yaffs2_checkpt_wr
 482                               (dev, &base_offset,
 483                                sizeof(base_offset)) == sizeof(base_offset));
 484                         if (ok)
 485                                 ok = (yaffs2_checkpt_wr
 486                                       (dev, tn,
 487                                        dev->tnode_size) == dev->tnode_size);
 488                 }
 489         }
 490
 491         return ok;
 492
 493 }
 494
 495 static int yaffs2_wr_checkpt_tnodes(struct yaffs_obj *obj)
 496 {
 497         u32 end_marker = ~0;
 498         int ok = 1;
 499
 500         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
 501                 ok = yaffs2_checkpt_tnode_worker(obj,
 502                                                  obj->variant.file_variant.top,
 503                                                  obj->variant.file_variant.
 504                                                  top_level, 0);
 505                 if (ok)
 506                         ok = (yaffs2_checkpt_wr
 507                               (obj->my_dev, &end_marker,
 508                                sizeof(end_marker)) == sizeof(end_marker));
 509         }
 510
 511         return ok ? 1 : 0;
 512 }
 513
 514 static int yaffs2_rd_checkpt_tnodes(struct yaffs_obj *obj)
 515 {
 516         u32 base_chunk;
 517         int ok = 1;
 518         struct yaffs_dev *dev = obj->my_dev;
 519         struct yaffs_file_var *file_stuct_ptr = &obj->variant.file_variant;
 520         struct yaffs_tnode *tn;
 521         int nread = 0;
 522
 523         ok = (yaffs2_checkpt_rd(dev, &base_chunk, sizeof(base_chunk)) ==
 524               sizeof(base_chunk));
 525
 526         while (ok && (~base_chunk)) {
 527                 nread++;
 528                 /* Read level 0 tnode */
 529
 530                 tn = yaffs_get_tnode(dev);
 531                 if (tn) {
 532                         ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) ==
 533                               dev->tnode_size);
 534                 } else {
 535                         ok = 0;
 536                 }
 537
 538                 if (tn && ok)
 539                         ok = yaffs_add_find_tnode_0(dev,
 540                                                     file_stuct_ptr,
 541                                                     base_chunk, tn) ? 1 : 0;
 542
 543                 if (ok)
 544                         ok = (yaffs2_checkpt_rd
 545                               (dev, &base_chunk,
 546                                sizeof(base_chunk)) == sizeof(base_chunk));
 547
 548         }
 549
 550         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 551                 "Checkpoint read tnodes %d records, last %d. ok %d",
 552                 nread, base_chunk, ok);
 553
 554         return ok ? 1 : 0;
 555 }
 556
 557 static int yaffs2_wr_checkpt_objs(struct yaffs_dev *dev)
 558 {
 559         struct yaffs_obj *obj;
 560         struct yaffs_checkpt_obj cp;
 561         int i;
 562         int ok = 1;
 563         struct list_head *lh;
 564
 565         /* Iterate through the objects in each hash entry,
 566          * dumping them to the checkpointing stream.
 567          */
 568
 569         for (i = 0; ok && i < YAFFS_NOBJECT_BUCKETS; i++) {
 570                 list_for_each(lh, &dev->obj_bucket[i].list) {
 571                         if (lh) {
 572                                 obj =
 573                                     list_entry(lh, struct yaffs_obj, hash_link);
 574                                 if (!obj->defered_free) {
 575                                         yaffs2_obj_checkpt_obj(&cp, obj);
 576                                         cp.struct_type = sizeof(cp);
 577
 578                                         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 579                                                 "Checkpoint write object %d parent %d type %d chunk %d obj addr %p",
 580                                                 cp.obj_id, cp.parent_id,
 581                                                 cp.variant_type, cp.hdr_chunk, obj);
 582
 583                                         ok = (yaffs2_checkpt_wr
 584                                               (dev, &cp,
 585                                                sizeof(cp)) == sizeof(cp));
 586
 587                                         if (ok
 588                                             && obj->variant_type ==
 589                                             YAFFS_OBJECT_TYPE_FILE)
 590                                                 ok = yaffs2_wr_checkpt_tnodes
 591                                                     (obj);
 592                                 }
 593                         }
 594                 }
 595         }
 596
 597         /* Dump end of list */
 598         memset(&cp, 0xFF, sizeof(struct yaffs_checkpt_obj));
 599         cp.struct_type = sizeof(cp);
 600
 601         if (ok)
 602                 ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 603
 604         return ok ? 1 : 0;
 605 }
 606
 607 static int yaffs2_rd_checkpt_objs(struct yaffs_dev *dev)
 608 {
 609         struct yaffs_obj *obj;
 610         struct yaffs_checkpt_obj cp;
 611         int ok = 1;
 612         int done = 0;
 613         struct yaffs_obj *hard_list = NULL;
 614
 615         while (ok && !done) {
 616                 ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 617                 if (cp.struct_type != sizeof(cp)) {
 618                         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 619                                 "struct size %d instead of %d ok %d",
 620                                 cp.struct_type, (int)sizeof(cp), ok);
 621                         ok = 0;
 622                 }
 623
 624                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 625                         "Checkpoint read object %d parent %d type %d chunk %d ",
 626                         cp.obj_id, cp.parent_id, cp.variant_type,
 627                         cp.hdr_chunk);
 628
 629                 if (ok && cp.obj_id == ~0) {
 630                         done = 1;
 631                 } else if (ok) {
 632                         obj =
 633                             yaffs_find_or_create_by_number(dev, cp.obj_id,
 634                                                            cp.variant_type);
 635                         if (obj) {
 636                                 ok = taffs2_checkpt_obj_to_obj(obj, &cp);
 637                                 if (!ok)
 638                                         break;
 639                                 if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
 640                                         ok = yaffs2_rd_checkpt_tnodes(obj);
 641                                 } else if (obj->variant_type ==
 642                                            YAFFS_OBJECT_TYPE_HARDLINK) {
 643                                         obj->hard_links.next =
 644                                             (struct list_head *)hard_list;
 645                                         hard_list = obj;
 646                                 }
 647                         } else {
 648                                 ok = 0;
 649                         }
 650                 }
 651         }
 652
 653         if (ok)
 654                 yaffs_link_fixup(dev, hard_list);
 655
 656         return ok ? 1 : 0;
 657 }
 658
 659 static int yaffs2_wr_checkpt_sum(struct yaffs_dev *dev)
 660 {
 661         u32 checkpt_sum;
 662         int ok;
 663
 664         yaffs2_get_checkpt_sum(dev, &checkpt_sum);
 665
 666         ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) ==
 667               sizeof(checkpt_sum));
 668
 669         if (!ok)
 670                 return 0;
 671
 672         return 1;
 673 }
 674
 675 static int yaffs2_rd_checkpt_sum(struct yaffs_dev *dev)
 676 {
 677         u32 checkpt_sum0;
 678         u32 checkpt_sum1;
 679         int ok;
 680
 681         yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
 682
 683         ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) ==
 684               sizeof(checkpt_sum1));
 685
 686         if (!ok)
 687                 return 0;
 688
 689         if (checkpt_sum0 != checkpt_sum1)
 690                 return 0;
 691
 692         return 1;
 693 }
 694
 695 static int yaffs2_wr_checkpt_data(struct yaffs_dev *dev)
 696 {
 697         int ok = 1;
 698
 699         if (!yaffs2_checkpt_required(dev)) {
 700                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 701                         "skipping checkpoint write");
 702                 ok = 0;
 703         }
 704
 705         if (ok)
 706                 ok = yaffs2_checkpt_open(dev, 1);
 707
 708         if (ok) {
 709                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 710                         "write checkpoint validity");
 711                 ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
 712         }
 713         if (ok) {
 714                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 715                         "write checkpoint device");
 716                 ok = yaffs2_wr_checkpt_dev(dev);
 717         }
 718         if (ok) {
 719                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 720                         "write checkpoint objects");
 721                 ok = yaffs2_wr_checkpt_objs(dev);
 722         }
 723         if (ok) {
 724                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 725                         "write checkpoint validity");
 726                 ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
 727         }
 728
 729         if (ok)
 730                 ok = yaffs2_wr_checkpt_sum(dev);
 731
 732         if (!yaffs_checkpt_close(dev))
 733                 ok = 0;
 734
 735         if (ok)
 736                 dev->is_checkpointed = 1;
 737         else
 738                 dev->is_checkpointed = 0;
 739
 740         return dev->is_checkpointed;
 741 }
 742
 743 static int yaffs2_rd_checkpt_data(struct yaffs_dev *dev)
 744 {
 745         int ok = 1;
 746
 747         if (!dev->param.is_yaffs2)
 748                 ok = 0;
 749
 750         if (ok && dev->param.skip_checkpt_rd) {
 751                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 752                         "skipping checkpoint read");
 753                 ok = 0;
 754         }
 755
 756         if (ok)
 757                 ok = yaffs2_checkpt_open(dev, 0); /* open for read */
 758
 759         if (ok) {
 760                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 761                         "read checkpoint validity");
 762                 ok = yaffs2_rd_checkpt_validity_marker(dev, 1);
 763         }
 764         if (ok) {
 765                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 766                         "read checkpoint device");
 767                 ok = yaffs2_rd_checkpt_dev(dev);
 768         }
 769         if (ok) {
 770                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 771                         "read checkpoint objects");
 772                 ok = yaffs2_rd_checkpt_objs(dev);
 773         }
 774         if (ok) {
 775                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 776                         "read checkpoint validity");
 777                 ok = yaffs2_rd_checkpt_validity_marker(dev, 0);
 778         }
 779
 780         if (ok) {
 781                 ok = yaffs2_rd_checkpt_sum(dev);
 782                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 783                         "read checkpoint checksum %d", ok);
 784         }
 785
 786         if (!yaffs_checkpt_close(dev))
 787                 ok = 0;
 788
 789         if (ok)
 790                 dev->is_checkpointed = 1;
 791         else
 792                 dev->is_checkpointed = 0;
 793
 794         return ok ? 1 : 0;
 795
 796 }
 797
 798 void yaffs2_checkpt_invalidate(struct yaffs_dev *dev)
 799 {
 800         if (dev->is_checkpointed || dev->blocks_in_checkpt > 0) {
 801                 dev->is_checkpointed = 0;
 802                 yaffs2_checkpt_invalidate_stream(dev);
 803         }
 804         if (dev->param.sb_dirty_fn)
 805                 dev->param.sb_dirty_fn(dev);
 806 }
 807
 808 int yaffs_checkpoint_save(struct yaffs_dev *dev)
 809 {
 810
 811         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 812                 "save entry: is_checkpointed %d",
 813                 dev->is_checkpointed);
 814
 815         yaffs_verify_objects(dev);
 816         yaffs_verify_blocks(dev);
 817         yaffs_verify_free_chunks(dev);
 818
 819         if (!dev->is_checkpointed) {
 820                 yaffs2_checkpt_invalidate(dev);
 821                 yaffs2_wr_checkpt_data(dev);
 822         }
 823
 824         yaffs_trace(YAFFS_TRACE_CHECKPOINT | YAFFS_TRACE_MOUNT,
 825                 "save exit: is_checkpointed %d",
 826                 dev->is_checkpointed);
 827
 828         return dev->is_checkpointed;
 829 }
 830
 831 int yaffs2_checkpt_restore(struct yaffs_dev *dev)
 832 {
 833         int retval;
 834         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 835                 "restore entry: is_checkpointed %d",
 836                 dev->is_checkpointed);
 837
 838         retval = yaffs2_rd_checkpt_data(dev);
 839
 840         if (dev->is_checkpointed) {
 841                 yaffs_verify_objects(dev);
 842                 yaffs_verify_blocks(dev);
 843                 yaffs_verify_free_chunks(dev);
 844         }
 845
 846         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 847                 "restore exit: is_checkpointed %d",
 848                 dev->is_checkpointed);
 849
 850         return retval;
 851 }
 852
 853 int yaffs2_handle_hole(struct yaffs_obj *obj, loff_t new_size)
 854 {
 855         /* if new_size > old_file_size.
 856          * We're going to be writing a hole.
 857          * If the hole is small then write zeros otherwise write a start of hole marker.
 858          */
 859
 860         loff_t old_file_size;
 861         int increase;
 862         int small_hole;
 863         int result = YAFFS_OK;
 864         struct yaffs_dev *dev = NULL;
 865
 866         u8 *local_buffer = NULL;
 867
 868         int small_increase_ok = 0;
 869
 870         if (!obj)
 871                 return YAFFS_FAIL;
 872
 873         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
 874                 return YAFFS_FAIL;
 875
 876         dev = obj->my_dev;
 877
 878         /* Bail out if not yaffs2 mode */
 879         if (!dev->param.is_yaffs2)
 880                 return YAFFS_OK;
 881
 882         old_file_size = obj->variant.file_variant.file_size;
 883
 884         if (new_size <= old_file_size)
 885                 return YAFFS_OK;
 886
 887         increase = new_size - old_file_size;
 888
 889         if (increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
 890             yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
 891                 small_hole = 1;
 892         else
 893                 small_hole = 0;
 894
 895         if (small_hole)
 896                 local_buffer = yaffs_get_temp_buffer(dev, __LINE__);
 897
 898         if (local_buffer) {
 899                 /* fill hole with zero bytes */
 900                 int pos = old_file_size;
 901                 int this_write;
 902                 int written;
 903                 memset(local_buffer, 0, dev->data_bytes_per_chunk);
 904                 small_increase_ok = 1;
 905
 906                 while (increase > 0 && small_increase_ok) {
 907                         this_write = increase;
 908                         if (this_write > dev->data_bytes_per_chunk)
 909                                 this_write = dev->data_bytes_per_chunk;
 910                         written =
 911                             yaffs_do_file_wr(obj, local_buffer, pos, this_write,
 912                                              0);
 913                         if (written == this_write) {
 914                                 pos += this_write;
 915                                 increase -= this_write;
 916                         } else {
 917                                 small_increase_ok = 0;
 918                         }
 919                 }
 920
 921                 yaffs_release_temp_buffer(dev, local_buffer, __LINE__);
 922
 923                 /* If we were out of space then reverse any chunks we've added */
 924                 if (!small_increase_ok)
 925                         yaffs_resize_file_down(obj, old_file_size);
 926         }
 927
 928         if (!small_increase_ok &&
 929             obj->parent &&
 930             obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
 931             obj->parent->obj_id != YAFFS_OBJECTID_DELETED) {
 932                 /* Write a hole start header with the old file size */
 933                 yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
 934         }
 935
 936         return result;
 937
 938 }
 939
 940 struct yaffs_block_index {
 941         int seq;
 942         int block;
 943 };
 944
 945 static int yaffs2_ybicmp(const void *a, const void *b)
 946 {
 947         int aseq = ((struct yaffs_block_index *)a)->seq;
 948         int bseq = ((struct yaffs_block_index *)b)->seq;
 949         int ablock = ((struct yaffs_block_index *)a)->block;
 950         int bblock = ((struct yaffs_block_index *)b)->block;
 951         if (aseq == bseq)
 952                 return ablock - bblock;
 953         else
 954                 return aseq - bseq;
 955 }
 956
 957 int yaffs2_scan_backwards(struct yaffs_dev *dev)
 958 {
 959         struct yaffs_ext_tags tags;
 960         int blk;
 961         int block_iter;
 962         int start_iter;
 963         int end_iter;
 964         int n_to_scan = 0;
 965
 966         int chunk;
 967         int result;
 968         int c;
 969         int deleted;
 970         enum yaffs_block_state state;
 971         struct yaffs_obj *hard_list = NULL;
 972         struct yaffs_block_info *bi;
 973         u32 seq_number;
 974         struct yaffs_obj_hdr *oh;
 975         struct yaffs_obj *in;
 976         struct yaffs_obj *parent;
 977         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
 978         int is_unlinked;
 979         u8 *chunk_data;
 980
 981         int file_size;
 982         int is_shrink;
 983         int found_chunks;
 984         int equiv_id;
 985         int alloc_failed = 0;
 986
 987         struct yaffs_block_index *block_index = NULL;
 988         int alt_block_index = 0;
 989
 990         yaffs_trace(YAFFS_TRACE_SCAN,
 991                 "yaffs2_scan_backwards starts  intstartblk %d intendblk %d...",
 992                 dev->internal_start_block, dev->internal_end_block);
 993
 994         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
 995
 996         block_index = kmalloc(n_blocks * sizeof(struct yaffs_block_index),
 997                         GFP_NOFS);
 998
 999         if (!block_index) {
1000                 block_index =
1001                     vmalloc(n_blocks * sizeof(struct yaffs_block_index));
1002                 alt_block_index = 1;
1003         }
1004
1005         if (!block_index) {
1006                 yaffs_trace(YAFFS_TRACE_SCAN,
1007                         "yaffs2_scan_backwards() could not allocate block index!"
1008                         );
1009                 return YAFFS_FAIL;
1010         }
1011
1012         dev->blocks_in_checkpt = 0;
1013
1014         chunk_data = yaffs_get_temp_buffer(dev, __LINE__);
1015
1016         /* Scan all the blocks to determine their state */
1017         bi = dev->block_info;
1018         for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
1019              blk++) {
1020                 yaffs_clear_chunk_bits(dev, blk);
1021                 bi->pages_in_use = 0;
1022                 bi->soft_del_pages = 0;
1023
1024                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
1025
1026                 bi->block_state = state;
1027                 bi->seq_number = seq_number;
1028
1029                 if (bi->seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA)
1030                         bi->block_state = state = YAFFS_BLOCK_STATE_CHECKPOINT;
1031                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
1032                         bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
1033
1034                 yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
1035                         "Block scanning block %d state %d seq %d",
1036                         blk, state, seq_number);
1037
1038                 if (state == YAFFS_BLOCK_STATE_CHECKPOINT) {
1039                         dev->blocks_in_checkpt++;
1040
1041                 } else if (state == YAFFS_BLOCK_STATE_DEAD) {
1042                         yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
1043                                 "block %d is bad", blk);
1044                 } else if (state == YAFFS_BLOCK_STATE_EMPTY) {
1045                         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
1046                         dev->n_erased_blocks++;
1047                         dev->n_free_chunks += dev->param.chunks_per_block;
1048                 } else if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
1049
1050                         /* Determine the highest sequence number */
1051                         if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
1052                             seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
1053
1054                                 block_index[n_to_scan].seq = seq_number;
1055                                 block_index[n_to_scan].block = blk;
1056
1057                                 n_to_scan++;
1058
1059                                 if (seq_number >= dev->seq_number)
1060                                         dev->seq_number = seq_number;
1061                         } else {
1062                                 /* TODO: Nasty sequence number! */
1063                                 yaffs_trace(YAFFS_TRACE_SCAN,
1064                                         "Block scanning block %d has bad sequence number %d",
1065                                         blk, seq_number);
1066
1067                         }
1068                 }
1069                 bi++;
1070         }
1071
1072         yaffs_trace(YAFFS_TRACE_SCAN, "%d blocks to be sorted...", n_to_scan);
1073
1074         cond_resched();
1075
1076         /* Sort the blocks by sequence number */
1077         sort(block_index, n_to_scan, sizeof(struct yaffs_block_index),
1078                    yaffs2_ybicmp, NULL);
1079
1080         cond_resched();
1081
1082         yaffs_trace(YAFFS_TRACE_SCAN, "...done");
1083
1084         /* Now scan the blocks looking at the data. */
1085         start_iter = 0;
1086         end_iter = n_to_scan - 1;
1087         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "%d blocks to scan", n_to_scan);
1088
1089         /* For each block.... backwards */
1090         for (block_iter = end_iter; !alloc_failed && block_iter >= start_iter;
1091              block_iter--) {
1092                 /* Cooperative multitasking! This loop can run for so
1093                    long that watchdog timers expire. */
1094                 cond_resched();
1095
1096                 /* get the block to scan in the correct order */
1097                 blk = block_index[block_iter].block;
1098
1099                 bi = yaffs_get_block_info(dev, blk);
1100
1101                 state = bi->block_state;
1102
1103                 deleted = 0;
1104
1105                 /* For each chunk in each block that needs scanning.... */
1106                 found_chunks = 0;
1107                 for (c = dev->param.chunks_per_block - 1;
1108                      !alloc_failed && c >= 0 &&
1109                      (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
1110                       state == YAFFS_BLOCK_STATE_ALLOCATING); c--) {
1111                         /* Scan backwards...
1112                          * Read the tags and decide what to do
1113                          */
1114
1115                         chunk = blk * dev->param.chunks_per_block + c;
1116
1117                         result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL,
1118                                                           &tags);
1119
1120                         /* Let's have a good look at this chunk... */
1121
1122                         if (!tags.chunk_used) {
1123                                 /* An unassigned chunk in the block.
1124                                  * If there are used chunks after this one, then
1125                                  * it is a chunk that was skipped due to failing the erased
1126                                  * check. Just skip it so that it can be deleted.
1127                                  * But, more typically, We get here when this is an unallocated
1128                                  * chunk and his means that either the block is empty or
1129                                  * this is the one being allocated from
1130                                  */
1131
1132                                 if (found_chunks) {
1133                                         /* This is a chunk that was skipped due to failing the erased check */
1134                                 } else if (c == 0) {
1135                                         /* We're looking at the first chunk in the block so the block is unused */
1136                                         state = YAFFS_BLOCK_STATE_EMPTY;
1137                                         dev->n_erased_blocks++;
1138                                 } else {
1139                                         if (state ==
1140                                             YAFFS_BLOCK_STATE_NEEDS_SCANNING
1141                                             || state ==
1142                                             YAFFS_BLOCK_STATE_ALLOCATING) {
1143                                                 if (dev->seq_number ==
1144                                                     bi->seq_number) {
1145                                                         /* this is the block being allocated from */
1146
1147                                                         yaffs_trace(YAFFS_TRACE_SCAN,
1148                                                                 " Allocating from %d %d",
1149                                                                 blk, c);
1150
1151                                                         state =
1152                                                             YAFFS_BLOCK_STATE_ALLOCATING;
1153                                                         dev->alloc_block = blk;
1154                                                         dev->alloc_page = c;
1155                                                         dev->
1156                                                             alloc_block_finder =
1157                                                             blk;
1158                                                 } else {
1159                                                         /* This is a partially written block that is not
1160                                                          * the current allocation block.
1161                                                          */
1162
1163                                                         yaffs_trace(YAFFS_TRACE_SCAN,
1164                                                                 "Partially written block %d detected",
1165                                                                 blk);
1166                                                 }
1167                                         }
1168                                 }
1169
1170                                 dev->n_free_chunks++;
1171
1172                         } else if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED) {
1173                                 yaffs_trace(YAFFS_TRACE_SCAN,
1174                                         " Unfixed ECC in chunk(%d:%d), chunk ignored",
1175                                         blk, c);
1176
1177                                 dev->n_free_chunks++;
1178
1179                         } else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
1180                                    tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
1181                                    (tags.chunk_id > 0
1182                                     && tags.n_bytes > dev->data_bytes_per_chunk)
1183                                    || tags.seq_number != bi->seq_number) {
1184                                 yaffs_trace(YAFFS_TRACE_SCAN,
1185                                         "Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored",
1186                                         blk, c, tags.obj_id,
1187                                         tags.chunk_id, tags.n_bytes);
1188
1189                                 dev->n_free_chunks++;
1190
1191                         } else if (tags.chunk_id > 0) {
1192                                 /* chunk_id > 0 so it is a data chunk... */
1193                                 unsigned int endpos;
1194                                 u32 chunk_base =
1195                                     (tags.chunk_id -
1196                                      1) * dev->data_bytes_per_chunk;
1197
1198                                 found_chunks = 1;
1199
1200                                 yaffs_set_chunk_bit(dev, blk, c);
1201                                 bi->pages_in_use++;
1202
1203                                 in = yaffs_find_or_create_by_number(dev,
1204                                                                     tags.obj_id,
1205                                                                     YAFFS_OBJECT_TYPE_FILE);
1206                                 if (!in) {
1207                                         /* Out of memory */
1208                                         alloc_failed = 1;
1209                                 }
1210
1211                                 if (in &&
1212                                     in->variant_type == YAFFS_OBJECT_TYPE_FILE
1213                                     && chunk_base <
1214                                     in->variant.file_variant.shrink_size) {
1215                                         /* This has not been invalidated by a resize */
1216                                         if (!yaffs_put_chunk_in_file
1217                                             (in, tags.chunk_id, chunk, -1)) {
1218                                                 alloc_failed = 1;
1219                                         }
1220
1221                                         /* File size is calculated by looking at the data chunks if we have not
1222                                          * seen an object header yet. Stop this practice once we find an object header.
1223                                          */
1224                                         endpos = chunk_base + tags.n_bytes;
1225
1226                                         if (!in->valid &&       /* have not got an object header yet */
1227                                             in->variant.file_variant.
1228                                             scanned_size < endpos) {
1229                                                 in->variant.file_variant.
1230                                                     scanned_size = endpos;
1231                                                 in->variant.file_variant.
1232                                                     file_size = endpos;
1233                                         }
1234
1235                                 } else if (in) {
1236                                         /* This chunk has been invalidated by a resize, or a past file deletion
1237                                          * so delete the chunk*/
1238                                         yaffs_chunk_del(dev, chunk, 1,
1239                                                         __LINE__);
1240
1241                                 }
1242                         } else {
1243                                 /* chunk_id == 0, so it is an ObjectHeader.
1244                                  * Thus, we read in the object header and make the object
1245                                  */
1246                                 found_chunks = 1;
1247
1248                                 yaffs_set_chunk_bit(dev, blk, c);
1249                                 bi->pages_in_use++;
1250
1251                                 oh = NULL;
1252                                 in = NULL;
1253
1254                                 if (tags.extra_available) {
1255                                         in = yaffs_find_or_create_by_number(dev,
1256                                                                             tags.
1257                                                                             obj_id,
1258                                                                             tags.
1259                                                                             extra_obj_type);
1260                                         if (!in)
1261                                                 alloc_failed = 1;
1262                                 }
1263
1264                                 if (!in ||
1265                                     (!in->valid && dev->param.disable_lazy_load)
1266                                     || tags.extra_shadows || (!in->valid
1267                                                               && (tags.obj_id ==
1268                                                                   YAFFS_OBJECTID_ROOT
1269                                                                   || tags.
1270                                                                   obj_id ==
1271                                                                   YAFFS_OBJECTID_LOSTNFOUND)))
1272                                 {
1273
1274                                         /* If we don't have  valid info then we need to read the chunk
1275                                          * TODO In future we can probably defer reading the chunk and
1276                                          * living with invalid data until needed.
1277                                          */
1278
1279                                         result = yaffs_rd_chunk_tags_nand(dev,
1280                                                                           chunk,
1281                                                                           chunk_data,
1282                                                                           NULL);
1283
1284                                         oh = (struct yaffs_obj_hdr *)chunk_data;
1285
1286                                         if (dev->param.inband_tags) {
1287                                                 /* Fix up the header if they got corrupted by inband tags */
1288                                                 oh->shadows_obj =
1289                                                     oh->inband_shadowed_obj_id;
1290                                                 oh->is_shrink =
1291                                                     oh->inband_is_shrink;
1292                                         }
1293
1294                                         if (!in) {
1295                                                 in = yaffs_find_or_create_by_number(dev, tags.obj_id, oh->type);
1296                                                 if (!in)
1297                                                         alloc_failed = 1;
1298                                         }
1299
1300                                 }
1301
1302                                 if (!in) {
1303                                         /* TODO Hoosterman we have a problem! */
1304                                         yaffs_trace(YAFFS_TRACE_ERROR,
1305                                                 "yaffs tragedy: Could not make object for object  %d at chunk %d during scan",
1306                                                 tags.obj_id, chunk);
1307                                         continue;
1308                                 }
1309
1310                                 if (in->valid) {
1311                                         /* We have already filled this one.
1312                                          * We have a duplicate that will be discarded, but
1313                                          * we first have to suck out resize info if it is a file.
1314                                          */
1315
1316                                         if ((in->variant_type ==
1317                                              YAFFS_OBJECT_TYPE_FILE) && ((oh
1318                                                                           &&
1319                                                                           oh->
1320                                                                           type
1321                                                                           ==
1322                                                                           YAFFS_OBJECT_TYPE_FILE)
1323                                                                          ||
1324                                                                          (tags.
1325                                                                           extra_available
1326                                                                           &&
1327                                                                           tags.
1328                                                                           extra_obj_type
1329                                                                           ==
1330                                                                           YAFFS_OBJECT_TYPE_FILE)))
1331                                         {
1332                                                 u32 this_size =
1333                                                     (oh) ? oh->
1334                                                     file_size :
1335                                                     tags.extra_length;
1336                                                 u32 parent_obj_id =
1337                                                     (oh) ? oh->parent_obj_id :
1338                                                     tags.extra_parent_id;
1339
1340                                                 is_shrink =
1341                                                     (oh) ? oh->
1342                                                     is_shrink :
1343                                                     tags.extra_is_shrink;
1344
1345                                                 /* If it is deleted (unlinked at start also means deleted)
1346                                                  * we treat the file size as being zeroed at this point.
1347                                                  */
1348                                                 if (parent_obj_id ==
1349                                                     YAFFS_OBJECTID_DELETED
1350                                                     || parent_obj_id ==
1351                                                     YAFFS_OBJECTID_UNLINKED) {
1352                                                         this_size = 0;
1353                                                         is_shrink = 1;
1354                                                 }
1355
1356                                                 if (is_shrink
1357                                                     && in->variant.file_variant.
1358                                                     shrink_size > this_size)
1359                                                         in->variant.
1360                                                             file_variant.
1361                                                             shrink_size =
1362                                                             this_size;
1363
1364                                                 if (is_shrink)
1365                                                         bi->has_shrink_hdr = 1;
1366
1367                                         }
1368                                         /* Use existing - destroy this one. */
1369                                         yaffs_chunk_del(dev, chunk, 1,
1370                                                         __LINE__);
1371
1372                                 }
1373
1374                                 if (!in->valid && in->variant_type !=
1375                                     (oh ? oh->type : tags.extra_obj_type))
1376                                         yaffs_trace(YAFFS_TRACE_ERROR,
1377                                                 "yaffs tragedy: Bad object type, %d != %d, for object %d at chunk %d during scan",
1378                                                 oh ?
1379                                                 oh->type : tags.extra_obj_type,
1380                                                 in->variant_type, tags.obj_id,
1381                                                 chunk);
1382
1383                                 if (!in->valid &&
1384                                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1385                                      tags.obj_id ==
1386                                      YAFFS_OBJECTID_LOSTNFOUND)) {
1387                                         /* We only load some info, don't fiddle with directory structure */
1388                                         in->valid = 1;
1389
1390                                         if (oh) {
1391
1392                                                 in->yst_mode = oh->yst_mode;
1393                                                 yaffs_load_attribs(in, oh);
1394                                                 in->lazy_loaded = 0;
1395                                         } else {
1396                                                 in->lazy_loaded = 1;
1397                                         }
1398                                         in->hdr_chunk = chunk;
1399
1400                                 } else if (!in->valid) {
1401                                         /* we need to load this info */
1402
1403                                         in->valid = 1;
1404                                         in->hdr_chunk = chunk;
1405
1406                                         if (oh) {
1407                                                 in->variant_type = oh->type;
1408
1409                                                 in->yst_mode = oh->yst_mode;
1410                                                 yaffs_load_attribs(in, oh);
1411
1412                                                 if (oh->shadows_obj > 0)
1413                                                         yaffs_handle_shadowed_obj
1414                                                             (dev,
1415                                                              oh->shadows_obj,
1416                                                              1);
1417
1418                                                 yaffs_set_obj_name_from_oh(in,
1419                                                                            oh);
1420                                                 parent =
1421                                                     yaffs_find_or_create_by_number
1422                                                     (dev, oh->parent_obj_id,
1423                                                      YAFFS_OBJECT_TYPE_DIRECTORY);
1424
1425                                                 file_size = oh->file_size;
1426                                                 is_shrink = oh->is_shrink;
1427                                                 equiv_id = oh->equiv_id;
1428
1429                                         } else {
1430                                                 in->variant_type =
1431                                                     tags.extra_obj_type;
1432                                                 parent =
1433                                                     yaffs_find_or_create_by_number
1434                                                     (dev, tags.extra_parent_id,
1435                                                      YAFFS_OBJECT_TYPE_DIRECTORY);
1436                                                 file_size = tags.extra_length;
1437                                                 is_shrink =
1438                                                     tags.extra_is_shrink;
1439                                                 equiv_id = tags.extra_equiv_id;
1440                                                 in->lazy_loaded = 1;
1441
1442                                         }
1443                                         in->dirty = 0;
1444
1445                                         if (!parent)
1446                                                 alloc_failed = 1;
1447
1448                                         /* directory stuff...
1449                                          * hook up to parent
1450                                          */
1451
1452                                         if (parent && parent->variant_type ==
1453                                             YAFFS_OBJECT_TYPE_UNKNOWN) {
1454                                                 /* Set up as a directory */
1455                                                 parent->variant_type =
1456                                                     YAFFS_OBJECT_TYPE_DIRECTORY;
1457                                                 INIT_LIST_HEAD(&parent->
1458                                                                variant.dir_variant.children);
1459                                         } else if (!parent
1460                                                    || parent->variant_type !=
1461                                                    YAFFS_OBJECT_TYPE_DIRECTORY) {
1462                                                 /* Hoosterman, another problem....
1463                                                  * We're trying to use a non-directory as a directory
1464                                                  */
1465
1466                                                 yaffs_trace(YAFFS_TRACE_ERROR,
1467                                                         "yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
1468                                                         );
1469                                                 parent = dev->lost_n_found;
1470                                         }
1471
1472                                         yaffs_add_obj_to_dir(parent, in);
1473
1474                                         is_unlinked = (parent == dev->del_dir)
1475                                             || (parent == dev->unlinked_dir);
1476
1477                                         if (is_shrink) {
1478                                                 /* Mark the block as having a shrink header */
1479                                                 bi->has_shrink_hdr = 1;
1480                                         }
1481
1482                                         /* Note re hardlinks.
1483                                          * Since we might scan a hardlink before its equivalent object is scanned
1484                                          * we put them all in a list.
1485                                          * After scanning is complete, we should have all the objects, so we run
1486                                          * through this list and fix up all the chains.
1487                                          */
1488
1489                                         switch (in->variant_type) {
1490                                         case YAFFS_OBJECT_TYPE_UNKNOWN:
1491                                                 /* Todo got a problem */
1492                                                 break;
1493                                         case YAFFS_OBJECT_TYPE_FILE:
1494
1495                                                 if (in->variant.
1496                                                     file_variant.scanned_size <
1497                                                     file_size) {
1498                                                         /* This covers the case where the file size is greater
1499                                                          * than where the data is
1500                                                          * This will happen if the file is resized to be larger
1501                                                          * than its current data extents.
1502                                                          */
1503                                                         in->variant.
1504                                                             file_variant.
1505                                                             file_size =
1506                                                             file_size;
1507                                                         in->variant.
1508                                                             file_variant.
1509                                                             scanned_size =
1510                                                             file_size;
1511                                                 }
1512
1513                                                 if (in->variant.file_variant.
1514                                                     shrink_size > file_size)
1515                                                         in->variant.
1516                                                             file_variant.
1517                                                             shrink_size =
1518                                                             file_size;
1519
1520                                                 break;
1521                                         case YAFFS_OBJECT_TYPE_HARDLINK:
1522                                                 if (!is_unlinked) {
1523                                                         in->variant.
1524                                                             hardlink_variant.
1525                                                             equiv_id = equiv_id;
1526                                                         in->hard_links.next =
1527                                                             (struct list_head *)
1528                                                             hard_list;
1529                                                         hard_list = in;
1530                                                 }
1531                                                 break;
1532                                         case YAFFS_OBJECT_TYPE_DIRECTORY:
1533                                                 /* Do nothing */
1534                                                 break;
1535                                         case YAFFS_OBJECT_TYPE_SPECIAL:
1536                                                 /* Do nothing */
1537                                                 break;
1538                                         case YAFFS_OBJECT_TYPE_SYMLINK:
1539                                                 if (oh) {
1540                                                         in->variant.
1541                                                             symlink_variant.
1542                                                             alias =
1543                                                             yaffs_clone_str(oh->
1544                                                                             alias);
1545                                                         if (!in->variant.
1546                                                             symlink_variant.
1547                                                             alias)
1548                                                                 alloc_failed =
1549                                                                     1;
1550                                                 }
1551                                                 break;
1552                                         }
1553
1554                                 }
1555
1556                         }
1557
1558                 }               /* End of scanning for each chunk */
1559
1560                 if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
1561                         /* If we got this far while scanning, then the block is fully allocated. */
1562                         state = YAFFS_BLOCK_STATE_FULL;
1563                 }
1564
1565                 bi->block_state = state;
1566
1567                 /* Now let's see if it was dirty */
1568                 if (bi->pages_in_use == 0 &&
1569                     !bi->has_shrink_hdr &&
1570                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
1571                         yaffs_block_became_dirty(dev, blk);
1572                 }
1573
1574         }
1575
1576         yaffs_skip_rest_of_block(dev);
1577
1578         if (alt_block_index)
1579                 vfree(block_index);
1580         else
1581                 kfree(block_index);
1582
1583         /* Ok, we've done all the scanning.
1584          * Fix up the hard link chains.
1585          * We should now have scanned all the objects, now it's time to add these
1586          * hardlinks.
1587          */
1588         yaffs_link_fixup(dev, hard_list);
1589
1590         yaffs_release_temp_buffer(dev, chunk_data, __LINE__);
1591
1592         if (alloc_failed)
1593                 return YAFFS_FAIL;
1594
1595         yaffs_trace(YAFFS_TRACE_SCAN, "yaffs2_scan_backwards ends");
1596
1597         return YAFFS_OK;
1598 }