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                 T(YAFFS_TRACE_GC,
 190                   (TSTR
 191                    ("GC refresh count %d selected block %d with seq_number %d"
 192                     TENDSTR), dev->refresh_count, oldest, oldest_seq));
 193         }
 194
 195         return oldest;
 196 }
 197
 198 int yaffs2_checkpt_required(struct yaffs_dev *dev)
 199 {
 200         int nblocks;
 201
 202         if (!dev->param.is_yaffs2)
 203                 return 0;
 204
 205         nblocks = dev->internal_end_block - dev->internal_start_block + 1;
 206
 207         return !dev->param.skip_checkpt_wr &&
 208             !dev->read_only && (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
 209 }
 210
 211 int yaffs_calc_checkpt_blocks_required(struct yaffs_dev *dev)
 212 {
 213         int retval;
 214
 215         if (!dev->param.is_yaffs2)
 216                 return 0;
 217
 218         if (!dev->checkpoint_blocks_required && yaffs2_checkpt_required(dev)) {
 219                 /* Not a valid value so recalculate */
 220                 int n_bytes = 0;
 221                 int n_blocks;
 222                 int dev_blocks =
 223                     (dev->param.end_block - dev->param.start_block + 1);
 224
 225                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 226                 n_bytes += sizeof(struct yaffs_checkpt_dev);
 227                 n_bytes += dev_blocks * sizeof(struct yaffs_block_info);
 228                 n_bytes += dev_blocks * dev->chunk_bit_stride;
 229                 n_bytes +=
 230                     (sizeof(struct yaffs_checkpt_obj) +
 231                      sizeof(u32)) * (dev->n_obj);
 232                 n_bytes += (dev->tnode_size + sizeof(u32)) * (dev->n_tnodes);
 233                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 234                 n_bytes += sizeof(u32); /* checksum */
 235
 236                 /* Round up and add 2 blocks to allow for some bad blocks, so add 3 */
 237
 238                 n_blocks =
 239                     (n_bytes /
 240                      (dev->data_bytes_per_chunk *
 241                       dev->param.chunks_per_block)) + 3;
 242
 243                 dev->checkpoint_blocks_required = n_blocks;
 244         }
 245
 246         retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
 247         if (retval < 0)
 248                 retval = 0;
 249         return retval;
 250 }
 251
 252 /*--------------------- Checkpointing --------------------*/
 253
 254 static int yaffs2_wr_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 255 {
 256         struct yaffs_checkpt_validity cp;
 257
 258         memset(&cp, 0, sizeof(cp));
 259
 260         cp.struct_type = sizeof(cp);
 261         cp.magic = YAFFS_MAGIC;
 262         cp.version = YAFFS_CHECKPOINT_VERSION;
 263         cp.head = (head) ? 1 : 0;
 264
 265         return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ? 1 : 0;
 266 }
 267
 268 static int yaffs2_rd_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 269 {
 270         struct yaffs_checkpt_validity cp;
 271         int ok;
 272
 273         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 274
 275         if (ok)
 276                 ok = (cp.struct_type == sizeof(cp)) &&
 277                     (cp.magic == YAFFS_MAGIC) &&
 278                     (cp.version == YAFFS_CHECKPOINT_VERSION) &&
 279                     (cp.head == ((head) ? 1 : 0));
 280         return ok ? 1 : 0;
 281 }
 282
 283 static void yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev *cp,
 284                                       struct yaffs_dev *dev)
 285 {
 286         cp->n_erased_blocks = dev->n_erased_blocks;
 287         cp->alloc_block = dev->alloc_block;
 288         cp->alloc_page = dev->alloc_page;
 289         cp->n_free_chunks = dev->n_free_chunks;
 290
 291         cp->n_deleted_files = dev->n_deleted_files;
 292         cp->n_unlinked_files = dev->n_unlinked_files;
 293         cp->n_bg_deletions = dev->n_bg_deletions;
 294         cp->seq_number = dev->seq_number;
 295
 296 }
 297
 298 static void yaffs_checkpt_dev_to_dev(struct yaffs_dev *dev,
 299                                      struct yaffs_checkpt_dev *cp)
 300 {
 301         dev->n_erased_blocks = cp->n_erased_blocks;
 302         dev->alloc_block = cp->alloc_block;
 303         dev->alloc_page = cp->alloc_page;
 304         dev->n_free_chunks = cp->n_free_chunks;
 305
 306         dev->n_deleted_files = cp->n_deleted_files;
 307         dev->n_unlinked_files = cp->n_unlinked_files;
 308         dev->n_bg_deletions = cp->n_bg_deletions;
 309         dev->seq_number = cp->seq_number;
 310 }
 311
 312 static int yaffs2_wr_checkpt_dev(struct yaffs_dev *dev)
 313 {
 314         struct yaffs_checkpt_dev cp;
 315         u32 n_bytes;
 316         u32 n_blocks =
 317             (dev->internal_end_block - dev->internal_start_block + 1);
 318
 319         int ok;
 320
 321         /* Write device runtime values */
 322         yaffs2_dev_to_checkpt_dev(&cp, dev);
 323         cp.struct_type = sizeof(cp);
 324
 325         ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 326
 327         /* Write block info */
 328         if (ok) {
 329                 n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 330                 ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) ==
 331                       n_bytes);
 332         }
 333
 334         /* Write chunk bits */
 335         if (ok) {
 336                 n_bytes = n_blocks * dev->chunk_bit_stride;
 337                 ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) ==
 338                       n_bytes);
 339         }
 340         return ok ? 1 : 0;
 341
 342 }
 343
 344 static int yaffs2_rd_checkpt_dev(struct yaffs_dev *dev)
 345 {
 346         struct yaffs_checkpt_dev cp;
 347         u32 n_bytes;
 348         u32 n_blocks =
 349             (dev->internal_end_block - dev->internal_start_block + 1);
 350
 351         int ok;
 352
 353         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 354         if (!ok)
 355                 return 0;
 356
 357         if (cp.struct_type != sizeof(cp))
 358                 return 0;
 359
 360         yaffs_checkpt_dev_to_dev(dev, &cp);
 361
 362         n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 363
 364         ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
 365
 366         if (!ok)
 367                 return 0;
 368         n_bytes = n_blocks * dev->chunk_bit_stride;
 369
 370         ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
 371
 372         return ok ? 1 : 0;
 373 }
 374
 375 static void yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj *cp,
 376                                    struct yaffs_obj *obj)
 377 {
 378
 379         cp->obj_id = obj->obj_id;
 380         cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
 381         cp->hdr_chunk = obj->hdr_chunk;
 382         cp->variant_type = obj->variant_type;
 383         cp->deleted = obj->deleted;
 384         cp->soft_del = obj->soft_del;
 385         cp->unlinked = obj->unlinked;
 386         cp->fake = obj->fake;
 387         cp->rename_allowed = obj->rename_allowed;
 388         cp->unlink_allowed = obj->unlink_allowed;
 389         cp->serial = obj->serial;
 390         cp->n_data_chunks = obj->n_data_chunks;
 391
 392         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 393                 cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
 394         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 395                 cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
 396 }
 397
 398 static int taffs2_checkpt_obj_to_obj(struct yaffs_obj *obj,
 399                                      struct yaffs_checkpt_obj *cp)
 400 {
 401
 402         struct yaffs_obj *parent;
 403
 404         if (obj->variant_type != cp->variant_type) {
 405                 T(YAFFS_TRACE_ERROR, (TSTR("Checkpoint read object %d type %d "
 406                                            TCONT
 407                                            ("chunk %d does not match existing object type %d")
 408                                            TENDSTR), cp->obj_id,
 409                                       cp->variant_type, cp->hdr_chunk,
 410                                       obj->variant_type));
 411                 return 0;
 412         }
 413
 414         obj->obj_id = cp->obj_id;
 415
 416         if (cp->parent_id)
 417                 parent = yaffs_find_or_create_by_number(obj->my_dev,
 418                                                         cp->parent_id,
 419                                                         YAFFS_OBJECT_TYPE_DIRECTORY);
 420         else
 421                 parent = NULL;
 422
 423         if (parent) {
 424                 if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
 425                         T(YAFFS_TRACE_ALWAYS,
 426                           (TSTR
 427                            ("Checkpoint read object %d parent %d type %d"
 428                             TCONT(" chunk %d Parent type, %d, not directory")
 429                             TENDSTR), cp->obj_id, cp->parent_id,
 430                            cp->variant_type, cp->hdr_chunk,
 431                            parent->variant_type));
 432                         return 0;
 433                 }
 434                 yaffs_add_obj_to_dir(parent, obj);
 435         }
 436
 437         obj->hdr_chunk = cp->hdr_chunk;
 438         obj->variant_type = cp->variant_type;
 439         obj->deleted = cp->deleted;
 440         obj->soft_del = cp->soft_del;
 441         obj->unlinked = cp->unlinked;
 442         obj->fake = cp->fake;
 443         obj->rename_allowed = cp->rename_allowed;
 444         obj->unlink_allowed = cp->unlink_allowed;
 445         obj->serial = cp->serial;
 446         obj->n_data_chunks = cp->n_data_chunks;
 447
 448         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 449                 obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
 450         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 451                 obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
 452
 453         if (obj->hdr_chunk > 0)
 454                 obj->lazy_loaded = 1;
 455         return 1;
 456 }
 457
 458 static int yaffs2_checkpt_tnode_worker(struct yaffs_obj *in,
 459                                        struct yaffs_tnode *tn, u32 level,
 460                                        int chunk_offset)
 461 {
 462         int i;
 463         struct yaffs_dev *dev = in->my_dev;
 464         int ok = 1;
 465
 466         if (tn) {
 467                 if (level > 0) {
 468
 469                         for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
 470                                 if (tn->internal[i]) {
 471                                         ok = yaffs2_checkpt_tnode_worker(in,
 472                                                                          tn->
 473                                                                          internal
 474                                                                          [i],
 475                                                                          level -
 476                                                                          1,
 477                                                                          (chunk_offset
 478                                                                           <<
 479                                                                           YAFFS_TNODES_INTERNAL_BITS)
 480                                                                          + i);
 481                                 }
 482                         }
 483                 } else if (level == 0) {
 484                         u32 base_offset =
 485                             chunk_offset << YAFFS_TNODES_LEVEL0_BITS;
 486                         ok = (yaffs2_checkpt_wr
 487                               (dev, &base_offset,
 488                                sizeof(base_offset)) == sizeof(base_offset));
 489                         if (ok)
 490                                 ok = (yaffs2_checkpt_wr
 491                                       (dev, tn,
 492                                        dev->tnode_size) == dev->tnode_size);
 493                 }
 494         }
 495
 496         return ok;
 497
 498 }
 499
 500 static int yaffs2_wr_checkpt_tnodes(struct yaffs_obj *obj)
 501 {
 502         u32 end_marker = ~0;
 503         int ok = 1;
 504
 505         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
 506                 ok = yaffs2_checkpt_tnode_worker(obj,
 507                                                  obj->variant.file_variant.top,
 508                                                  obj->variant.file_variant.
 509                                                  top_level, 0);
 510                 if (ok)
 511                         ok = (yaffs2_checkpt_wr
 512                               (obj->my_dev, &end_marker,
 513                                sizeof(end_marker)) == sizeof(end_marker));
 514         }
 515
 516         return ok ? 1 : 0;
 517 }
 518
 519 static int yaffs2_rd_checkpt_tnodes(struct yaffs_obj *obj)
 520 {
 521         u32 base_chunk;
 522         int ok = 1;
 523         struct yaffs_dev *dev = obj->my_dev;
 524         struct yaffs_file_var *file_stuct_ptr = &obj->variant.file_variant;
 525         struct yaffs_tnode *tn;
 526         int nread = 0;
 527
 528         ok = (yaffs2_checkpt_rd(dev, &base_chunk, sizeof(base_chunk)) ==
 529               sizeof(base_chunk));
 530
 531         while (ok && (~base_chunk)) {
 532                 nread++;
 533                 /* Read level 0 tnode */
 534
 535                 tn = yaffs_get_tnode(dev);
 536                 if (tn) {
 537                         ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) ==
 538                               dev->tnode_size);
 539                 } else
 540                         ok = 0;
 541
 542                 if (tn && ok)
 543                         ok = yaffs_add_find_tnode_0(dev,
 544                                                     file_stuct_ptr,
 545                                                     base_chunk, tn) ? 1 : 0;
 546
 547                 if (ok)
 548                         ok = (yaffs2_checkpt_rd
 549                               (dev, &base_chunk,
 550                                sizeof(base_chunk)) == sizeof(base_chunk));
 551
 552         }
 553
 554         T(YAFFS_TRACE_CHECKPOINT,
 555           (TSTR("Checkpoint read tnodes %d records, last %d. ok %d" TENDSTR),
 556            nread, base_chunk, ok));
 557
 558         return ok ? 1 : 0;
 559 }
 560
 561 static int yaffs2_wr_checkpt_objs(struct yaffs_dev *dev)
 562 {
 563         struct yaffs_obj *obj;
 564         struct yaffs_checkpt_obj cp;
 565         int i;
 566         int ok = 1;
 567         struct list_head *lh;
 568
 569         /* Iterate through the objects in each hash entry,
 570          * dumping them to the checkpointing stream.
 571          */
 572
 573         for (i = 0; ok && i < YAFFS_NOBJECT_BUCKETS; i++) {
 574                 list_for_each(lh, &dev->obj_bucket[i].list) {
 575                         if (lh) {
 576                                 obj =
 577                                     list_entry(lh, struct yaffs_obj, hash_link);
 578                                 if (!obj->defered_free) {
 579                                         yaffs2_obj_checkpt_obj(&cp, obj);
 580                                         cp.struct_type = sizeof(cp);
 581
 582                                         T(YAFFS_TRACE_CHECKPOINT,
 583                                           (TSTR
 584                                            ("Checkpoint write object %d parent %d type %d chunk %d obj addr %p"
 585                                             TENDSTR), cp.obj_id, cp.parent_id,
 586                                            cp.variant_type, cp.hdr_chunk, obj));
 587
 588                                         ok = (yaffs2_checkpt_wr
 589                                               (dev, &cp,
 590                                                sizeof(cp)) == sizeof(cp));
 591
 592                                         if (ok
 593                                             && obj->variant_type ==
 594                                             YAFFS_OBJECT_TYPE_FILE)
 595                                                 ok = yaffs2_wr_checkpt_tnodes
 596                                                     (obj);
 597                                 }
 598                         }
 599                 }
 600         }
 601
 602         /* Dump end of list */
 603         memset(&cp, 0xFF, sizeof(struct yaffs_checkpt_obj));
 604         cp.struct_type = sizeof(cp);
 605
 606         if (ok)
 607                 ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 608
 609         return ok ? 1 : 0;
 610 }
 611
 612 static int yaffs2_rd_checkpt_objs(struct yaffs_dev *dev)
 613 {
 614         struct yaffs_obj *obj;
 615         struct yaffs_checkpt_obj cp;
 616         int ok = 1;
 617         int done = 0;
 618         struct yaffs_obj *hard_list = NULL;
 619
 620         while (ok && !done) {
 621                 ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 622                 if (cp.struct_type != sizeof(cp)) {
 623                         T(YAFFS_TRACE_CHECKPOINT,
 624                           (TSTR("struct size %d instead of %d ok %d" TENDSTR),
 625                            cp.struct_type, (int)sizeof(cp), ok));
 626                         ok = 0;
 627                 }
 628
 629                 T(YAFFS_TRACE_CHECKPOINT,
 630                   (TSTR
 631                    ("Checkpoint read object %d parent %d type %d chunk %d "
 632                     TENDSTR), cp.obj_id, cp.parent_id, cp.variant_type,
 633                    cp.hdr_chunk));
 634
 635                 if (ok && cp.obj_id == ~0)
 636                         done = 1;
 637                 else if (ok) {
 638                         obj =
 639                             yaffs_find_or_create_by_number(dev, cp.obj_id,
 640                                                            cp.variant_type);
 641                         if (obj) {
 642                                 ok = taffs2_checkpt_obj_to_obj(obj, &cp);
 643                                 if (!ok)
 644                                         break;
 645                                 if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
 646                                         ok = yaffs2_rd_checkpt_tnodes(obj);
 647                                 } else if (obj->variant_type ==
 648                                            YAFFS_OBJECT_TYPE_HARDLINK) {
 649                                         obj->hard_links.next =
 650                                             (struct list_head *)hard_list;
 651                                         hard_list = obj;
 652                                 }
 653                         } else
 654                                 ok = 0;
 655                 }
 656         }
 657
 658         if (ok)
 659                 yaffs_link_fixup(dev, hard_list);
 660
 661         return ok ? 1 : 0;
 662 }
 663
 664 static int yaffs2_wr_checkpt_sum(struct yaffs_dev *dev)
 665 {
 666         u32 checkpt_sum;
 667         int ok;
 668
 669         yaffs2_get_checkpt_sum(dev, &checkpt_sum);
 670
 671         ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) ==
 672               sizeof(checkpt_sum));
 673
 674         if (!ok)
 675                 return 0;
 676
 677         return 1;
 678 }
 679
 680 static int yaffs2_rd_checkpt_sum(struct yaffs_dev *dev)
 681 {
 682         u32 checkpt_sum0;
 683         u32 checkpt_sum1;
 684         int ok;
 685
 686         yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
 687
 688         ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) ==
 689               sizeof(checkpt_sum1));
 690
 691         if (!ok)
 692                 return 0;
 693
 694         if (checkpt_sum0 != checkpt_sum1)
 695                 return 0;
 696
 697         return 1;
 698 }
 699
 700 static int yaffs2_wr_checkpt_data(struct yaffs_dev *dev)
 701 {
 702         int ok = 1;
 703
 704         if (!yaffs2_checkpt_required(dev)) {
 705                 T(YAFFS_TRACE_CHECKPOINT,
 706                   (TSTR("skipping checkpoint write" TENDSTR)));
 707                 ok = 0;
 708         }
 709
 710         if (ok)
 711                 ok = yaffs2_checkpt_open(dev, 1);
 712
 713         if (ok) {
 714                 T(YAFFS_TRACE_CHECKPOINT,
 715                   (TSTR("write checkpoint validity" TENDSTR)));
 716                 ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
 717         }
 718         if (ok) {
 719                 T(YAFFS_TRACE_CHECKPOINT,
 720                   (TSTR("write checkpoint device" TENDSTR)));
 721                 ok = yaffs2_wr_checkpt_dev(dev);
 722         }
 723         if (ok) {
 724                 T(YAFFS_TRACE_CHECKPOINT,
 725                   (TSTR("write checkpoint objects" TENDSTR)));
 726                 ok = yaffs2_wr_checkpt_objs(dev);
 727         }
 728         if (ok) {
 729                 T(YAFFS_TRACE_CHECKPOINT,
 730                   (TSTR("write checkpoint validity" TENDSTR)));
 731                 ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
 732         }
 733
 734         if (ok)
 735                 ok = yaffs2_wr_checkpt_sum(dev);
 736
 737         if (!yaffs_checkpt_close(dev))
 738                 ok = 0;
 739
 740         if (ok)
 741                 dev->is_checkpointed = 1;
 742         else
 743                 dev->is_checkpointed = 0;
 744
 745         return dev->is_checkpointed;
 746 }
 747
 748 static int yaffs2_rd_checkpt_data(struct yaffs_dev *dev)
 749 {
 750         int ok = 1;
 751
 752         if (!dev->param.is_yaffs2)
 753                 ok = 0;
 754
 755         if (ok && dev->param.skip_checkpt_rd) {
 756                 T(YAFFS_TRACE_CHECKPOINT,
 757                   (TSTR("skipping checkpoint read" TENDSTR)));
 758                 ok = 0;
 759         }
 760
 761         if (ok)
 762                 ok = yaffs2_checkpt_open(dev, 0);       /* open for read */
 763
 764         if (ok) {
 765                 T(YAFFS_TRACE_CHECKPOINT,
 766                   (TSTR("read checkpoint validity" TENDSTR)));
 767                 ok = yaffs2_rd_checkpt_validity_marker(dev, 1);
 768         }
 769         if (ok) {
 770                 T(YAFFS_TRACE_CHECKPOINT,
 771                   (TSTR("read checkpoint device" TENDSTR)));
 772                 ok = yaffs2_rd_checkpt_dev(dev);
 773         }
 774         if (ok) {
 775                 T(YAFFS_TRACE_CHECKPOINT,
 776                   (TSTR("read checkpoint objects" TENDSTR)));
 777                 ok = yaffs2_rd_checkpt_objs(dev);
 778         }
 779         if (ok) {
 780                 T(YAFFS_TRACE_CHECKPOINT,
 781                   (TSTR("read checkpoint validity" TENDSTR)));
 782                 ok = yaffs2_rd_checkpt_validity_marker(dev, 0);
 783         }
 784
 785         if (ok) {
 786                 ok = yaffs2_rd_checkpt_sum(dev);
 787                 T(YAFFS_TRACE_CHECKPOINT,
 788                   (TSTR("read checkpoint checksum %d" TENDSTR), ok));
 789         }
 790
 791         if (!yaffs_checkpt_close(dev))
 792                 ok = 0;
 793
 794         if (ok)
 795                 dev->is_checkpointed = 1;
 796         else
 797                 dev->is_checkpointed = 0;
 798
 799         return ok ? 1 : 0;
 800
 801 }
 802
 803 void yaffs2_checkpt_invalidate(struct yaffs_dev *dev)
 804 {
 805         if (dev->is_checkpointed || dev->blocks_in_checkpt > 0) {
 806                 dev->is_checkpointed = 0;
 807                 yaffs2_checkpt_invalidate_stream(dev);
 808         }
 809         if (dev->param.sb_dirty_fn)
 810                 dev->param.sb_dirty_fn(dev);
 811 }
 812
 813 int yaffs_checkpoint_save(struct yaffs_dev *dev)
 814 {
 815
 816         T(YAFFS_TRACE_CHECKPOINT,
 817           (TSTR("save entry: is_checkpointed %d" TENDSTR),
 818            dev->is_checkpointed));
 819
 820         yaffs_verify_objects(dev);
 821         yaffs_verify_blocks(dev);
 822         yaffs_verify_free_chunks(dev);
 823
 824         if (!dev->is_checkpointed) {
 825                 yaffs2_checkpt_invalidate(dev);
 826                 yaffs2_wr_checkpt_data(dev);
 827         }
 828
 829         T(YAFFS_TRACE_ALWAYS,
 830           (TSTR("save exit: is_checkpointed %d" TENDSTR),
 831            dev->is_checkpointed));
 832
 833         return dev->is_checkpointed;
 834 }
 835
 836 int yaffs2_checkpt_restore(struct yaffs_dev *dev)
 837 {
 838         int retval;
 839         T(YAFFS_TRACE_CHECKPOINT,
 840           (TSTR("restore entry: is_checkpointed %d" TENDSTR),
 841            dev->is_checkpointed));
 842
 843         retval = yaffs2_rd_checkpt_data(dev);
 844
 845         if (dev->is_checkpointed) {
 846                 yaffs_verify_objects(dev);
 847                 yaffs_verify_blocks(dev);
 848                 yaffs_verify_free_chunks(dev);
 849         }
 850
 851         T(YAFFS_TRACE_CHECKPOINT,
 852           (TSTR("restore exit: is_checkpointed %d" TENDSTR),
 853            dev->is_checkpointed));
 854
 855         return retval;
 856 }
 857
 858 int yaffs2_handle_hole(struct yaffs_obj *obj, loff_t new_size)
 859 {
 860         /* if new_size > old_file_size.
 861          * We're going to be writing a hole.
 862          * If the hole is small then write zeros otherwise write a start of hole marker.
 863          */
 864
 865         loff_t old_file_size;
 866         int increase;
 867         int small_hole;
 868         int result = YAFFS_OK;
 869         struct yaffs_dev *dev = NULL;
 870
 871         u8 *local_buffer = NULL;
 872
 873         int small_increase_ok = 0;
 874
 875         if (!obj)
 876                 return YAFFS_FAIL;
 877
 878         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
 879                 return YAFFS_FAIL;
 880
 881         dev = obj->my_dev;
 882
 883         /* Bail out if not yaffs2 mode */
 884         if (!dev->param.is_yaffs2)
 885                 return YAFFS_OK;
 886
 887         old_file_size = obj->variant.file_variant.file_size;
 888
 889         if (new_size <= old_file_size)
 890                 return YAFFS_OK;
 891
 892         increase = new_size - old_file_size;
 893
 894         if (increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
 895             yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
 896                 small_hole = 1;
 897         else
 898                 small_hole = 0;
 899
 900         if (small_hole)
 901                 local_buffer = yaffs_get_temp_buffer(dev, __LINE__);
 902
 903         if (local_buffer) {
 904                 /* fill hole with zero bytes */
 905                 int pos = old_file_size;
 906                 int this_write;
 907                 int written;
 908                 memset(local_buffer, 0, dev->data_bytes_per_chunk);
 909                 small_increase_ok = 1;
 910
 911                 while (increase > 0 && small_increase_ok) {
 912                         this_write = increase;
 913                         if (this_write > dev->data_bytes_per_chunk)
 914                                 this_write = dev->data_bytes_per_chunk;
 915                         written =
 916                             yaffs_do_file_wr(obj, local_buffer, pos, this_write,
 917                                              0);
 918                         if (written == this_write) {
 919                                 pos += this_write;
 920                                 increase -= this_write;
 921                         } else
 922                                 small_increase_ok = 0;
 923                 }
 924
 925                 yaffs_release_temp_buffer(dev, local_buffer, __LINE__);
 926
 927                 /* If we were out of space then reverse any chunks we've added */
 928                 if (!small_increase_ok)
 929                         yaffs_resize_file_down(obj, old_file_size);
 930         }
 931
 932         if (!small_increase_ok &&
 933             obj->parent &&
 934             obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
 935             obj->parent->obj_id != YAFFS_OBJECTID_DELETED) {
 936                 /* Write a hole start header with the old file size */
 937                 yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
 938         }
 939
 940         return result;
 941
 942 }
 943
 944 struct yaffs_block_index {
 945         int seq;
 946         int block;
 947 };
 948
 949 static int yaffs2_ybicmp(const void *a, const void *b)
 950 {
 951         int aseq = ((struct yaffs_block_index *)a)->seq;
 952         int bseq = ((struct yaffs_block_index *)b)->seq;
 953         int ablock = ((struct yaffs_block_index *)a)->block;
 954         int bblock = ((struct yaffs_block_index *)b)->block;
 955         if (aseq == bseq)
 956                 return ablock - bblock;
 957         else
 958                 return aseq - bseq;
 959 }
 960
 961 int yaffs2_scan_backwards(struct yaffs_dev *dev)
 962 {
 963         struct yaffs_ext_tags tags;
 964         int blk;
 965         int block_iter;
 966         int start_iter;
 967         int end_iter;
 968         int n_to_scan = 0;
 969
 970         int chunk;
 971         int result;
 972         int c;
 973         int deleted;
 974         enum yaffs_block_state state;
 975         struct yaffs_obj *hard_list = NULL;
 976         struct yaffs_block_info *bi;
 977         u32 seq_number;
 978         struct yaffs_obj_hdr *oh;
 979         struct yaffs_obj *in;
 980         struct yaffs_obj *parent;
 981         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
 982         int is_unlinked;
 983         u8 *chunk_data;
 984
 985         int file_size;
 986         int is_shrink;
 987         int found_chunks;
 988         int equiv_id;
 989         int alloc_failed = 0;
 990
 991         struct yaffs_block_index *block_index = NULL;
 992         int alt_block_index = 0;
 993
 994         T(YAFFS_TRACE_SCAN,
 995           (TSTR
 996            ("yaffs2_scan_backwards starts  intstartblk %d intendblk %d..."
 997             TENDSTR), dev->internal_start_block, dev->internal_end_block));
 998
 999         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
1000
1001         block_index = YMALLOC(n_blocks * sizeof(struct yaffs_block_index));
1002
1003         if (!block_index) {
1004                 block_index =
1005                     YMALLOC_ALT(n_blocks * sizeof(struct yaffs_block_index));
1006                 alt_block_index = 1;
1007         }
1008
1009         if (!block_index) {
1010                 T(YAFFS_TRACE_SCAN,
1011                   (TSTR
1012                    ("yaffs2_scan_backwards() could not allocate block index!"
1013                     TENDSTR)));
1014                 return YAFFS_FAIL;
1015         }
1016
1017         dev->blocks_in_checkpt = 0;
1018
1019         chunk_data = yaffs_get_temp_buffer(dev, __LINE__);
1020
1021         /* Scan all the blocks to determine their state */
1022         bi = dev->block_info;
1023         for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
1024              blk++) {
1025                 yaffs_clear_chunk_bits(dev, blk);
1026                 bi->pages_in_use = 0;
1027                 bi->soft_del_pages = 0;
1028
1029                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
1030
1031                 bi->block_state = state;
1032                 bi->seq_number = seq_number;
1033
1034                 if (bi->seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA)
1035                         bi->block_state = state = YAFFS_BLOCK_STATE_CHECKPOINT;
1036                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
1037                         bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
1038
1039                 T(YAFFS_TRACE_SCAN_DEBUG,
1040                   (TSTR("Block scanning block %d state %d seq %d" TENDSTR), blk,
1041                    state, seq_number));
1042
1043                 if (state == YAFFS_BLOCK_STATE_CHECKPOINT) {
1044                         dev->blocks_in_checkpt++;
1045
1046                 } else if (state == YAFFS_BLOCK_STATE_DEAD) {
1047                         T(YAFFS_TRACE_BAD_BLOCKS,
1048                           (TSTR("block %d is bad" TENDSTR), blk));
1049                 } else if (state == YAFFS_BLOCK_STATE_EMPTY) {
1050                         T(YAFFS_TRACE_SCAN_DEBUG,
1051                           (TSTR("Block empty " TENDSTR)));
1052                         dev->n_erased_blocks++;
1053                         dev->n_free_chunks += dev->param.chunks_per_block;
1054                 } else if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
1055
1056                         /* Determine the highest sequence number */
1057                         if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
1058                             seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
1059
1060                                 block_index[n_to_scan].seq = seq_number;
1061                                 block_index[n_to_scan].block = blk;
1062
1063                                 n_to_scan++;
1064
1065                                 if (seq_number >= dev->seq_number)
1066                                         dev->seq_number = seq_number;
1067                         } else {
1068                                 /* TODO: Nasty sequence number! */
1069                                 T(YAFFS_TRACE_SCAN,
1070                                   (TSTR
1071                                    ("Block scanning block %d has bad sequence number %d"
1072                                     TENDSTR), blk, seq_number));
1073
1074                         }
1075                 }
1076                 bi++;
1077         }
1078
1079         T(YAFFS_TRACE_SCAN,
1080           (TSTR("%d blocks to be sorted..." TENDSTR), n_to_scan));
1081
1082         YYIELD();
1083
1084         /* Sort the blocks by sequence number */
1085         yaffs_sort(block_index, n_to_scan, sizeof(struct yaffs_block_index),
1086                    yaffs2_ybicmp);
1087
1088         YYIELD();
1089
1090         T(YAFFS_TRACE_SCAN, (TSTR("...done" TENDSTR)));
1091
1092         /* Now scan the blocks looking at the data. */
1093         start_iter = 0;
1094         end_iter = n_to_scan - 1;
1095         T(YAFFS_TRACE_SCAN_DEBUG,
1096           (TSTR("%d blocks to be scanned" TENDSTR), n_to_scan));
1097
1098         /* For each block.... backwards */
1099         for (block_iter = end_iter; !alloc_failed && block_iter >= start_iter;
1100              block_iter--) {
1101                 /* Cooperative multitasking! This loop can run for so
1102                    long that watchdog timers expire. */
1103                 YYIELD();
1104
1105                 /* get the block to scan in the correct order */
1106                 blk = block_index[block_iter].block;
1107
1108                 bi = yaffs_get_block_info(dev, blk);
1109
1110                 state = bi->block_state;
1111
1112                 deleted = 0;
1113
1114                 /* For each chunk in each block that needs scanning.... */
1115                 found_chunks = 0;
1116                 for (c = dev->param.chunks_per_block - 1;
1117                      !alloc_failed && c >= 0 &&
1118                      (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
1119                       state == YAFFS_BLOCK_STATE_ALLOCATING); c--) {
1120                         /* Scan backwards...
1121                          * Read the tags and decide what to do
1122                          */
1123
1124                         chunk = blk * dev->param.chunks_per_block + c;
1125
1126                         result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL,
1127                                                           &tags);
1128
1129                         /* Let's have a good look at this chunk... */
1130
1131                         if (!tags.chunk_used) {
1132                                 /* An unassigned chunk in the block.
1133                                  * If there are used chunks after this one, then
1134                                  * it is a chunk that was skipped due to failing the erased
1135                                  * check. Just skip it so that it can be deleted.
1136                                  * But, more typically, We get here when this is an unallocated
1137                                  * chunk and his means that either the block is empty or
1138                                  * this is the one being allocated from
1139                                  */
1140
1141                                 if (found_chunks) {
1142                                         /* This is a chunk that was skipped due to failing the erased check */
1143                                 } else if (c == 0) {
1144                                         /* We're looking at the first chunk in the block so the block is unused */
1145                                         state = YAFFS_BLOCK_STATE_EMPTY;
1146                                         dev->n_erased_blocks++;
1147                                 } else {
1148                                         if (state ==
1149                                             YAFFS_BLOCK_STATE_NEEDS_SCANNING
1150                                             || state ==
1151                                             YAFFS_BLOCK_STATE_ALLOCATING) {
1152                                                 if (dev->seq_number ==
1153                                                     bi->seq_number) {
1154                                                         /* this is the block being allocated from */
1155
1156                                                         T(YAFFS_TRACE_SCAN,
1157                                                           (TSTR
1158                                                            (" Allocating from %d %d"
1159                                                             TENDSTR), blk, c));
1160
1161                                                         state =
1162                                                             YAFFS_BLOCK_STATE_ALLOCATING;
1163                                                         dev->alloc_block = blk;
1164                                                         dev->alloc_page = c;
1165                                                         dev->
1166                                                             alloc_block_finder =
1167                                                             blk;
1168                                                 } else {
1169                                                         /* This is a partially written block that is not
1170                                                          * the current allocation block.
1171                                                          */
1172
1173                                                         T(YAFFS_TRACE_SCAN,
1174                                                           (TSTR
1175                                                            ("Partially written block %d detected"
1176                                                             TENDSTR), blk));
1177                                                 }
1178                                         }
1179                                 }
1180
1181                                 dev->n_free_chunks++;
1182
1183                         } else if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED) {
1184                                 T(YAFFS_TRACE_SCAN,
1185                                   (TSTR
1186                                    (" Unfixed ECC in chunk(%d:%d), chunk ignored"
1187                                     TENDSTR), blk, c));
1188
1189                                 dev->n_free_chunks++;
1190
1191                         } else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
1192                                    tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
1193                                    (tags.chunk_id > 0
1194                                     && tags.n_bytes > dev->data_bytes_per_chunk)
1195                                    || tags.seq_number != bi->seq_number) {
1196                                 T(YAFFS_TRACE_SCAN,
1197                                   (TSTR
1198                                    ("Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored"
1199                                     TENDSTR), blk, c, tags.obj_id,
1200                                    tags.chunk_id, tags.n_bytes));
1201
1202                                 dev->n_free_chunks++;
1203
1204                         } else if (tags.chunk_id > 0) {
1205                                 /* chunk_id > 0 so it is a data chunk... */
1206                                 unsigned int endpos;
1207                                 u32 chunk_base =
1208                                     (tags.chunk_id -
1209                                      1) * dev->data_bytes_per_chunk;
1210
1211                                 found_chunks = 1;
1212
1213                                 yaffs_set_chunk_bit(dev, blk, c);
1214                                 bi->pages_in_use++;
1215
1216                                 in = yaffs_find_or_create_by_number(dev,
1217                                                                     tags.obj_id,
1218                                                                     YAFFS_OBJECT_TYPE_FILE);
1219                                 if (!in) {
1220                                         /* Out of memory */
1221                                         alloc_failed = 1;
1222                                 }
1223
1224                                 if (in &&
1225                                     in->variant_type == YAFFS_OBJECT_TYPE_FILE
1226                                     && chunk_base <
1227                                     in->variant.file_variant.shrink_size) {
1228                                         /* This has not been invalidated by a resize */
1229                                         if (!yaffs_put_chunk_in_file
1230                                             (in, tags.chunk_id, chunk, -1)) {
1231                                                 alloc_failed = 1;
1232                                         }
1233
1234                                         /* File size is calculated by looking at the data chunks if we have not
1235                                          * seen an object header yet. Stop this practice once we find an object header.
1236                                          */
1237                                         endpos = chunk_base + tags.n_bytes;
1238
1239                                         if (!in->valid &&       /* have not got an object header yet */
1240                                             in->variant.file_variant.
1241                                             scanned_size < endpos) {
1242                                                 in->variant.file_variant.
1243                                                     scanned_size = endpos;
1244                                                 in->variant.file_variant.
1245                                                     file_size = endpos;
1246                                         }
1247
1248                                 } else if (in) {
1249                                         /* This chunk has been invalidated by a resize, or a past file deletion
1250                                          * so delete the chunk*/
1251                                         yaffs_chunk_del(dev, chunk, 1,
1252                                                         __LINE__);
1253
1254                                 }
1255                         } else {
1256                                 /* chunk_id == 0, so it is an ObjectHeader.
1257                                  * Thus, we read in the object header and make the object
1258                                  */
1259                                 found_chunks = 1;
1260
1261                                 yaffs_set_chunk_bit(dev, blk, c);
1262                                 bi->pages_in_use++;
1263
1264                                 oh = NULL;
1265                                 in = NULL;
1266
1267                                 if (tags.extra_available) {
1268                                         in = yaffs_find_or_create_by_number(dev,
1269                                                                             tags.
1270                                                                             obj_id,
1271                                                                             tags.
1272                                                                             extra_obj_type);
1273                                         if (!in)
1274                                                 alloc_failed = 1;
1275                                 }
1276
1277                                 if (!in ||
1278                                     (!in->valid && dev->param.disable_lazy_load)
1279                                     || tags.extra_shadows || (!in->valid
1280                                                               && (tags.obj_id ==
1281                                                                   YAFFS_OBJECTID_ROOT
1282                                                                   || tags.
1283                                                                   obj_id ==
1284                                                                   YAFFS_OBJECTID_LOSTNFOUND)))
1285                                 {
1286
1287                                         /* If we don't have  valid info then we need to read the chunk
1288                                          * TODO In future we can probably defer reading the chunk and
1289                                          * living with invalid data until needed.
1290                                          */
1291
1292                                         result = yaffs_rd_chunk_tags_nand(dev,
1293                                                                           chunk,
1294                                                                           chunk_data,
1295                                                                           NULL);
1296
1297                                         oh = (struct yaffs_obj_hdr *)chunk_data;
1298
1299                                         if (dev->param.inband_tags) {
1300                                                 /* Fix up the header if they got corrupted by inband tags */
1301                                                 oh->shadows_obj =
1302                                                     oh->inband_shadowed_obj_id;
1303                                                 oh->is_shrink =
1304                                                     oh->inband_is_shrink;
1305                                         }
1306
1307                                         if (!in) {
1308                                                 in = yaffs_find_or_create_by_number(dev, tags.obj_id, oh->type);
1309                                                 if (!in)
1310                                                         alloc_failed = 1;
1311                                         }
1312
1313                                 }
1314
1315                                 if (!in) {
1316                                         /* TODO Hoosterman we have a problem! */
1317                                         T(YAFFS_TRACE_ERROR,
1318                                           (TSTR
1319                                            ("yaffs tragedy: Could not make object for object  %d at chunk %d during scan"
1320                                             TENDSTR), tags.obj_id, chunk));
1321                                         continue;
1322                                 }
1323
1324                                 if (in->valid) {
1325                                         /* We have already filled this one.
1326                                          * We have a duplicate that will be discarded, but
1327                                          * we first have to suck out resize info if it is a file.
1328                                          */
1329
1330                                         if ((in->variant_type ==
1331                                              YAFFS_OBJECT_TYPE_FILE) && ((oh
1332                                                                           &&
1333                                                                           oh->
1334                                                                           type
1335                                                                           ==
1336                                                                           YAFFS_OBJECT_TYPE_FILE)
1337                                                                          ||
1338                                                                          (tags.
1339                                                                           extra_available
1340                                                                           &&
1341                                                                           tags.
1342                                                                           extra_obj_type
1343                                                                           ==
1344                                                                           YAFFS_OBJECT_TYPE_FILE)))
1345                                         {
1346                                                 u32 this_size =
1347                                                     (oh) ? oh->
1348                                                     file_size :
1349                                                     tags.extra_length;
1350                                                 u32 parent_obj_id =
1351                                                     (oh) ? oh->parent_obj_id :
1352                                                     tags.extra_parent_id;
1353
1354                                                 is_shrink =
1355                                                     (oh) ? oh->
1356                                                     is_shrink :
1357                                                     tags.extra_is_shrink;
1358
1359                                                 /* If it is deleted (unlinked at start also means deleted)
1360                                                  * we treat the file size as being zeroed at this point.
1361                                                  */
1362                                                 if (parent_obj_id ==
1363                                                     YAFFS_OBJECTID_DELETED
1364                                                     || parent_obj_id ==
1365                                                     YAFFS_OBJECTID_UNLINKED) {
1366                                                         this_size = 0;
1367                                                         is_shrink = 1;
1368                                                 }
1369
1370                                                 if (is_shrink
1371                                                     && in->variant.file_variant.
1372                                                     shrink_size > this_size)
1373                                                         in->variant.
1374                                                             file_variant.
1375                                                             shrink_size =
1376                                                             this_size;
1377
1378                                                 if (is_shrink)
1379                                                         bi->has_shrink_hdr = 1;
1380
1381                                         }
1382                                         /* Use existing - destroy this one. */
1383                                         yaffs_chunk_del(dev, chunk, 1,
1384                                                         __LINE__);
1385
1386                                 }
1387
1388                                 if (!in->valid && in->variant_type !=
1389                                     (oh ? oh->type : tags.extra_obj_type))
1390                                         T(YAFFS_TRACE_ERROR,
1391                                           (TSTR
1392                                            ("yaffs tragedy: Bad object type, "
1393                                             TCONT
1394                                             ("%d != %d, for object %d at chunk ")
1395                                             TCONT("%d during scan")
1396                                             TENDSTR), oh ?
1397                                            oh->type : tags.extra_obj_type,
1398                                            in->variant_type, tags.obj_id,
1399                                            chunk));
1400
1401                                 if (!in->valid &&
1402                                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1403                                      tags.obj_id ==
1404                                      YAFFS_OBJECTID_LOSTNFOUND)) {
1405                                         /* We only load some info, don't fiddle with directory structure */
1406                                         in->valid = 1;
1407
1408                                         if (oh) {
1409
1410                                                 in->yst_mode = oh->yst_mode;
1411                                                 yaffs_load_attribs(in, oh);
1412                                                 in->lazy_loaded = 0;
1413                                         } else
1414                                                 in->lazy_loaded = 1;
1415
1416                                         in->hdr_chunk = chunk;
1417
1418                                 } else if (!in->valid) {
1419                                         /* we need to load this info */
1420
1421                                         in->valid = 1;
1422                                         in->hdr_chunk = chunk;
1423
1424                                         if (oh) {
1425                                                 in->variant_type = oh->type;
1426
1427                                                 in->yst_mode = oh->yst_mode;
1428                                                 yaffs_load_attribs(in, oh);
1429
1430                                                 if (oh->shadows_obj > 0)
1431                                                         yaffs_handle_shadowed_obj
1432                                                             (dev,
1433                                                              oh->shadows_obj,
1434                                                              1);
1435
1436                                                 yaffs_set_obj_name_from_oh(in,
1437                                                                            oh);
1438                                                 parent =
1439                                                     yaffs_find_or_create_by_number
1440                                                     (dev, oh->parent_obj_id,
1441                                                      YAFFS_OBJECT_TYPE_DIRECTORY);
1442
1443                                                 file_size = oh->file_size;
1444                                                 is_shrink = oh->is_shrink;
1445                                                 equiv_id = oh->equiv_id;
1446
1447                                         } else {
1448                                                 in->variant_type =
1449                                                     tags.extra_obj_type;
1450                                                 parent =
1451                                                     yaffs_find_or_create_by_number
1452                                                     (dev, tags.extra_parent_id,
1453                                                      YAFFS_OBJECT_TYPE_DIRECTORY);
1454                                                 file_size = tags.extra_length;
1455                                                 is_shrink =
1456                                                     tags.extra_is_shrink;
1457                                                 equiv_id = tags.extra_equiv_id;
1458                                                 in->lazy_loaded = 1;
1459
1460                                         }
1461                                         in->dirty = 0;
1462
1463                                         if (!parent)
1464                                                 alloc_failed = 1;
1465
1466                                         /* directory stuff...
1467                                          * hook up to parent
1468                                          */
1469
1470                                         if (parent && parent->variant_type ==
1471                                             YAFFS_OBJECT_TYPE_UNKNOWN) {
1472                                                 /* Set up as a directory */
1473                                                 parent->variant_type =
1474                                                     YAFFS_OBJECT_TYPE_DIRECTORY;
1475                                                 INIT_LIST_HEAD(&parent->
1476                                                                variant.dir_variant.children);
1477                                         } else if (!parent
1478                                                    || parent->variant_type !=
1479                                                    YAFFS_OBJECT_TYPE_DIRECTORY)
1480                                         {
1481                                                 /* Hoosterman, another problem....
1482                                                  * We're trying to use a non-directory as a directory
1483                                                  */
1484
1485                                                 T(YAFFS_TRACE_ERROR,
1486                                                   (TSTR
1487                                                    ("yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
1488                                                     TENDSTR)));
1489                                                 parent = dev->lost_n_found;
1490                                         }
1491
1492                                         yaffs_add_obj_to_dir(parent, in);
1493
1494                                         is_unlinked = (parent == dev->del_dir)
1495                                             || (parent == dev->unlinked_dir);
1496
1497                                         if (is_shrink) {
1498                                                 /* Mark the block as having a shrink header */
1499                                                 bi->has_shrink_hdr = 1;
1500                                         }
1501
1502                                         /* Note re hardlinks.
1503                                          * Since we might scan a hardlink before its equivalent object is scanned
1504                                          * we put them all in a list.
1505                                          * After scanning is complete, we should have all the objects, so we run
1506                                          * through this list and fix up all the chains.
1507                                          */
1508
1509                                         switch (in->variant_type) {
1510                                         case YAFFS_OBJECT_TYPE_UNKNOWN:
1511                                                 /* Todo got a problem */
1512                                                 break;
1513                                         case YAFFS_OBJECT_TYPE_FILE:
1514
1515                                                 if (in->variant.
1516                                                     file_variant.scanned_size <
1517                                                     file_size) {
1518                                                         /* This covers the case where the file size is greater
1519                                                          * than where the data is
1520                                                          * This will happen if the file is resized to be larger
1521                                                          * than its current data extents.
1522                                                          */
1523                                                         in->variant.
1524                                                             file_variant.
1525                                                             file_size =
1526                                                             file_size;
1527                                                         in->variant.
1528                                                             file_variant.
1529                                                             scanned_size =
1530                                                             file_size;
1531                                                 }
1532
1533                                                 if (in->variant.file_variant.
1534                                                     shrink_size > file_size)
1535                                                         in->variant.
1536                                                             file_variant.
1537                                                             shrink_size =
1538                                                             file_size;
1539
1540                                                 break;
1541                                         case YAFFS_OBJECT_TYPE_HARDLINK:
1542                                                 if (!is_unlinked) {
1543                                                         in->variant.
1544                                                             hardlink_variant.
1545                                                             equiv_id = equiv_id;
1546                                                         in->hard_links.next =
1547                                                             (struct list_head *)
1548                                                             hard_list;
1549                                                         hard_list = in;
1550                                                 }
1551                                                 break;
1552                                         case YAFFS_OBJECT_TYPE_DIRECTORY:
1553                                                 /* Do nothing */
1554                                                 break;
1555                                         case YAFFS_OBJECT_TYPE_SPECIAL:
1556                                                 /* Do nothing */
1557                                                 break;
1558                                         case YAFFS_OBJECT_TYPE_SYMLINK:
1559                                                 if (oh) {
1560                                                         in->variant.
1561                                                             symlink_variant.
1562                                                             alias =
1563                                                             yaffs_clone_str(oh->
1564                                                                             alias);
1565                                                         if (!in->variant.
1566                                                             symlink_variant.
1567                                                             alias)
1568                                                                 alloc_failed =
1569                                                                     1;
1570                                                 }
1571                                                 break;
1572                                         }
1573
1574                                 }
1575
1576                         }
1577
1578                 }               /* End of scanning for each chunk */
1579
1580                 if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
1581                         /* If we got this far while scanning, then the block is fully allocated. */
1582                         state = YAFFS_BLOCK_STATE_FULL;
1583                 }
1584
1585                 bi->block_state = state;
1586
1587                 /* Now let's see if it was dirty */
1588                 if (bi->pages_in_use == 0 &&
1589                     !bi->has_shrink_hdr &&
1590                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
1591                         yaffs_block_became_dirty(dev, blk);
1592                 }
1593
1594         }
1595
1596         yaffs_skip_rest_of_block(dev);
1597
1598         if (alt_block_index)
1599                 YFREE_ALT(block_index);
1600         else
1601                 YFREE(block_index);
1602
1603         /* Ok, we've done all the scanning.
1604          * Fix up the hard link chains.
1605          * We should now have scanned all the objects, now it's time to add these
1606          * hardlinks.
1607          */
1608         yaffs_link_fixup(dev, hard_list);
1609
1610         yaffs_release_temp_buffer(dev, chunk_data, __LINE__);
1611
1612         if (alloc_failed)
1613                 return YAFFS_FAIL;
1614
1615         T(YAFFS_TRACE_SCAN, (TSTR("yaffs2_scan_backwards ends" TENDSTR)));
1616
1617         return YAFFS_OK;
1618 }