fs/yaffs2/yaffs_yaffs2.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2011 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 #include "yaffs_summary.h"
  24
  25 /*
  26  * Checkpoints are really no benefit on very small partitions.
  27  *
  28  * To save space on small partitions don't bother with checkpoints unless
  29  * the partition is at least this big.
  30  */
  31 #define YAFFS_CHECKPOINT_MIN_BLOCKS 60
  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 &&
  59                     b->seq_number < seq) {
  60                         seq = b->seq_number;
  61                         block_no = i;
  62                 }
  63                 b++;
  64         }
  65
  66         if (block_no) {
  67                 dev->oldest_dirty_seq = seq;
  68                 dev->oldest_dirty_block = block_no;
  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
 131          * one that have 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         u32 oldest = 0;
 145         u32 oldest_seq = 0;
 146         struct yaffs_block_info *bi;
 147
 148         if (!dev->param.is_yaffs2)
 149                 return oldest;
 150
 151         /*
 152          * If refresh period < 10 then refreshing is disabled.
 153          */
 154         if (dev->param.refresh_period < 10)
 155                 return oldest;
 156
 157         /*
 158          * Fix broken values.
 159          */
 160         if (dev->refresh_skip > dev->param.refresh_period)
 161                 dev->refresh_skip = dev->param.refresh_period;
 162
 163         if (dev->refresh_skip > 0)
 164                 return oldest;
 165
 166         /*
 167          * Refresh skip is now zero.
 168          * We'll do a refresh this time around....
 169          * Update the refresh skip and find the oldest block.
 170          */
 171         dev->refresh_skip = dev->param.refresh_period;
 172         dev->refresh_count++;
 173         bi = dev->block_info;
 174         for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
 175
 176                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL) {
 177
 178                         if (oldest < 1 || bi->seq_number < oldest_seq) {
 179                                 oldest = b;
 180                                 oldest_seq = bi->seq_number;
 181                         }
 182                 }
 183                 bi++;
 184         }
 185
 186         if (oldest > 0) {
 187                 yaffs_trace(YAFFS_TRACE_GC,
 188                         "GC refresh count %d selected block %d with seq_number %d",
 189                         dev->refresh_count, oldest, oldest_seq);
 190         }
 191
 192         return oldest;
 193 }
 194
 195 int yaffs2_checkpt_required(struct yaffs_dev *dev)
 196 {
 197         int nblocks;
 198
 199         if (!dev->param.is_yaffs2)
 200                 return 0;
 201
 202         nblocks = dev->internal_end_block - dev->internal_start_block + 1;
 203
 204         return !dev->param.skip_checkpt_wr &&
 205             !dev->read_only && (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
 206 }
 207
 208 int yaffs_calc_checkpt_blocks_required(struct yaffs_dev *dev)
 209 {
 210         int retval;
 211         int n_bytes = 0;
 212         int n_blocks;
 213         int dev_blocks;
 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                 dev_blocks = dev->param.end_block - dev->param.start_block + 1;
 221                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 222                 n_bytes += sizeof(struct yaffs_checkpt_dev);
 223                 n_bytes += dev_blocks * sizeof(struct yaffs_block_info);
 224                 n_bytes += dev_blocks * dev->chunk_bit_stride;
 225                 n_bytes +=
 226                     (sizeof(struct yaffs_checkpt_obj) + sizeof(u32)) *
 227                     dev->n_obj;
 228                 n_bytes += (dev->tnode_size + sizeof(u32)) * dev->n_tnodes;
 229                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 230                 n_bytes += sizeof(u32); /* checksum */
 231
 232                 /* Round up and add 2 blocks to allow for some bad blocks,
 233                  * so add 3 */
 234
 235                 n_blocks =
 236                     (n_bytes /
 237                      (dev->data_bytes_per_chunk *
 238                       dev->param.chunks_per_block)) + 3;
 239
 240                 dev->checkpoint_blocks_required = n_blocks;
 241         }
 242
 243         retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
 244         if (retval < 0)
 245                 retval = 0;
 246         return retval;
 247 }
 248
 249 /*--------------------- Checkpointing --------------------*/
 250
 251 static int yaffs2_wr_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 252 {
 253         struct yaffs_checkpt_validity cp;
 254
 255         memset(&cp, 0, sizeof(cp));
 256
 257         cp.struct_type = sizeof(cp);
 258         cp.magic = YAFFS_MAGIC;
 259         cp.version = YAFFS_CHECKPOINT_VERSION;
 260         cp.head = (head) ? 1 : 0;
 261
 262         return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ? 1 : 0;
 263 }
 264
 265 static int yaffs2_rd_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 266 {
 267         struct yaffs_checkpt_validity cp;
 268         int ok;
 269
 270         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 271
 272         if (ok)
 273                 ok = (cp.struct_type == sizeof(cp)) &&
 274                     (cp.magic == YAFFS_MAGIC) &&
 275                     (cp.version == YAFFS_CHECKPOINT_VERSION) &&
 276                     (cp.head == ((head) ? 1 : 0));
 277         return ok ? 1 : 0;
 278 }
 279
 280 static void yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev *cp,
 281                                       struct yaffs_dev *dev)
 282 {
 283         cp->n_erased_blocks = dev->n_erased_blocks;
 284         cp->alloc_block = dev->alloc_block;
 285         cp->alloc_page = dev->alloc_page;
 286         cp->n_free_chunks = dev->n_free_chunks;
 287
 288         cp->n_deleted_files = dev->n_deleted_files;
 289         cp->n_unlinked_files = dev->n_unlinked_files;
 290         cp->n_bg_deletions = dev->n_bg_deletions;
 291         cp->seq_number = dev->seq_number;
 292
 293 }
 294
 295 static void yaffs_checkpt_dev_to_dev(struct yaffs_dev *dev,
 296                                      struct yaffs_checkpt_dev *cp)
 297 {
 298         dev->n_erased_blocks = cp->n_erased_blocks;
 299         dev->alloc_block = cp->alloc_block;
 300         dev->alloc_page = cp->alloc_page;
 301         dev->n_free_chunks = cp->n_free_chunks;
 302
 303         dev->n_deleted_files = cp->n_deleted_files;
 304         dev->n_unlinked_files = cp->n_unlinked_files;
 305         dev->n_bg_deletions = cp->n_bg_deletions;
 306         dev->seq_number = cp->seq_number;
 307 }
 308
 309 static int yaffs2_wr_checkpt_dev(struct yaffs_dev *dev)
 310 {
 311         struct yaffs_checkpt_dev cp;
 312         u32 n_bytes;
 313         u32 n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
 314         int ok;
 315
 316         /* Write device runtime values */
 317         yaffs2_dev_to_checkpt_dev(&cp, dev);
 318         cp.struct_type = sizeof(cp);
 319
 320         ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 321         if (!ok)
 322                 return 0;
 323
 324         /* Write block info */
 325         n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 326         ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) == n_bytes);
 327         if (!ok)
 328                 return 0;
 329
 330         /* Write chunk bits */
 331         n_bytes = n_blocks * dev->chunk_bit_stride;
 332         ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) == n_bytes);
 333
 334         return ok ? 1 : 0;
 335 }
 336
 337 static int yaffs2_rd_checkpt_dev(struct yaffs_dev *dev)
 338 {
 339         struct yaffs_checkpt_dev cp;
 340         u32 n_bytes;
 341         u32 n_blocks =
 342             (dev->internal_end_block - dev->internal_start_block + 1);
 343         int ok;
 344
 345         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 346         if (!ok)
 347                 return 0;
 348
 349         if (cp.struct_type != sizeof(cp))
 350                 return 0;
 351
 352         yaffs_checkpt_dev_to_dev(dev, &cp);
 353
 354         n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 355
 356         ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
 357
 358         if (!ok)
 359                 return 0;
 360
 361         n_bytes = n_blocks * dev->chunk_bit_stride;
 362
 363         ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
 364
 365         return ok ? 1 : 0;
 366 }
 367
 368 static void yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj *cp,
 369                                    struct yaffs_obj *obj)
 370 {
 371         cp->obj_id = obj->obj_id;
 372         cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
 373         cp->hdr_chunk = obj->hdr_chunk;
 374         cp->variant_type = obj->variant_type;
 375         cp->deleted = obj->deleted;
 376         cp->soft_del = obj->soft_del;
 377         cp->unlinked = obj->unlinked;
 378         cp->fake = obj->fake;
 379         cp->rename_allowed = obj->rename_allowed;
 380         cp->unlink_allowed = obj->unlink_allowed;
 381         cp->serial = obj->serial;
 382         cp->n_data_chunks = obj->n_data_chunks;
 383
 384         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 385                 cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
 386         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 387                 cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
 388 }
 389
 390 static int yaffs2_checkpt_obj_to_obj(struct yaffs_obj *obj,
 391                                      struct yaffs_checkpt_obj *cp)
 392 {
 393         struct yaffs_obj *parent;
 394
 395         if (obj->variant_type != cp->variant_type) {
 396                 yaffs_trace(YAFFS_TRACE_ERROR,
 397                         "Checkpoint read object %d type %d chunk %d does not match existing object type %d",
 398                         cp->obj_id, cp->variant_type, cp->hdr_chunk,
 399                         obj->variant_type);
 400                 return 0;
 401         }
 402
 403         obj->obj_id = cp->obj_id;
 404
 405         if (cp->parent_id)
 406                 parent = yaffs_find_or_create_by_number(obj->my_dev,
 407                                                 cp->parent_id,
 408                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
 409         else
 410                 parent = NULL;
 411
 412         if (parent) {
 413                 if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
 414                         yaffs_trace(YAFFS_TRACE_ALWAYS,
 415                                 "Checkpoint read object %d parent %d type %d chunk %d Parent type, %d, not directory",
 416                                 cp->obj_id, cp->parent_id,
 417                                 cp->variant_type, cp->hdr_chunk,
 418                                 parent->variant_type);
 419                         return 0;
 420                 }
 421                 yaffs_add_obj_to_dir(parent, obj);
 422         }
 423
 424         obj->hdr_chunk = cp->hdr_chunk;
 425         obj->variant_type = cp->variant_type;
 426         obj->deleted = cp->deleted;
 427         obj->soft_del = cp->soft_del;
 428         obj->unlinked = cp->unlinked;
 429         obj->fake = cp->fake;
 430         obj->rename_allowed = cp->rename_allowed;
 431         obj->unlink_allowed = cp->unlink_allowed;
 432         obj->serial = cp->serial;
 433         obj->n_data_chunks = cp->n_data_chunks;
 434
 435         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 436                 obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
 437         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 438                 obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
 439
 440         if (obj->hdr_chunk > 0)
 441                 obj->lazy_loaded = 1;
 442         return 1;
 443 }
 444
 445 static int yaffs2_checkpt_tnode_worker(struct yaffs_obj *in,
 446                                        struct yaffs_tnode *tn, u32 level,
 447                                        int chunk_offset)
 448 {
 449         int i;
 450         struct yaffs_dev *dev = in->my_dev;
 451         int ok = 1;
 452         u32 base_offset;
 453
 454         if (!tn)
 455                 return 1;
 456
 457         if (level > 0) {
 458                 for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
 459                         if (!tn->internal[i])
 460                                 continue;
 461                         ok = yaffs2_checkpt_tnode_worker(in,
 462                                  tn->internal[i],
 463                                  level - 1,
 464                                  (chunk_offset <<
 465                                   YAFFS_TNODES_INTERNAL_BITS) + i);
 466                 }
 467                 return ok;
 468         }
 469
 470         /* Level 0 tnode */
 471         base_offset = chunk_offset << YAFFS_TNODES_LEVEL0_BITS;
 472         ok = (yaffs2_checkpt_wr(dev, &base_offset, sizeof(base_offset)) ==
 473                         sizeof(base_offset));
 474         if (ok)
 475                 ok = (yaffs2_checkpt_wr(dev, tn, dev->tnode_size) ==
 476                         dev->tnode_size);
 477
 478         return ok;
 479 }
 480
 481 static int yaffs2_wr_checkpt_tnodes(struct yaffs_obj *obj)
 482 {
 483         u32 end_marker = ~0;
 484         int ok = 1;
 485
 486         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
 487                 return ok;
 488
 489         ok = yaffs2_checkpt_tnode_worker(obj,
 490                                          obj->variant.file_variant.top,
 491                                          obj->variant.file_variant.
 492                                          top_level, 0);
 493         if (ok)
 494                 ok = (yaffs2_checkpt_wr(obj->my_dev, &end_marker,
 495                                 sizeof(end_marker)) == sizeof(end_marker));
 496
 497         return ok ? 1 : 0;
 498 }
 499
 500 static int yaffs2_rd_checkpt_tnodes(struct yaffs_obj *obj)
 501 {
 502         u32 base_chunk;
 503         int ok = 1;
 504         struct yaffs_dev *dev = obj->my_dev;
 505         struct yaffs_file_var *file_stuct_ptr = &obj->variant.file_variant;
 506         struct yaffs_tnode *tn;
 507         int nread = 0;
 508
 509         ok = (yaffs2_checkpt_rd(dev, &base_chunk, sizeof(base_chunk)) ==
 510               sizeof(base_chunk));
 511
 512         while (ok && (~base_chunk)) {
 513                 nread++;
 514                 /* Read level 0 tnode */
 515
 516                 tn = yaffs_get_tnode(dev);
 517                 if (tn)
 518                         ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) ==
 519                                 dev->tnode_size);
 520                 else
 521                         ok = 0;
 522
 523                 if (tn && ok)
 524                         ok = yaffs_add_find_tnode_0(dev,
 525                                                     file_stuct_ptr,
 526                                                     base_chunk, tn) ? 1 : 0;
 527
 528                 if (ok)
 529                         ok = (yaffs2_checkpt_rd
 530                               (dev, &base_chunk,
 531                                sizeof(base_chunk)) == sizeof(base_chunk));
 532         }
 533
 534         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 535                 "Checkpoint read tnodes %d records, last %d. ok %d",
 536                 nread, base_chunk, ok);
 537
 538         return ok ? 1 : 0;
 539 }
 540
 541 static int yaffs2_wr_checkpt_objs(struct yaffs_dev *dev)
 542 {
 543         struct yaffs_obj *obj;
 544         struct yaffs_checkpt_obj cp;
 545         int i;
 546         int ok = 1;
 547         struct list_head *lh;
 548
 549         /* Iterate through the objects in each hash entry,
 550          * dumping them to the checkpointing stream.
 551          */
 552
 553         for (i = 0; ok && i < YAFFS_NOBJECT_BUCKETS; i++) {
 554                 list_for_each(lh, &dev->obj_bucket[i].list) {
 555                         obj = list_entry(lh, struct yaffs_obj, hash_link);
 556                         if (!obj->defered_free) {
 557                                 yaffs2_obj_checkpt_obj(&cp, obj);
 558                                 cp.struct_type = sizeof(cp);
 559
 560                                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 561                                         "Checkpoint write object %d parent %d type %d chunk %d obj addr %p",
 562                                         cp.obj_id, cp.parent_id,
 563                                         cp.variant_type, cp.hdr_chunk, obj);
 564
 565                                 ok = (yaffs2_checkpt_wr(dev, &cp,
 566                                                 sizeof(cp)) == sizeof(cp));
 567
 568                                 if (ok &&
 569                                         obj->variant_type ==
 570                                         YAFFS_OBJECT_TYPE_FILE)
 571                                         ok = yaffs2_wr_checkpt_tnodes(obj);
 572                         }
 573                 }
 574         }
 575
 576         /* Dump end of list */
 577         memset(&cp, 0xff, sizeof(struct yaffs_checkpt_obj));
 578         cp.struct_type = sizeof(cp);
 579
 580         if (ok)
 581                 ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 582
 583         return ok ? 1 : 0;
 584 }
 585
 586 static int yaffs2_rd_checkpt_objs(struct yaffs_dev *dev)
 587 {
 588         struct yaffs_obj *obj;
 589         struct yaffs_checkpt_obj cp;
 590         int ok = 1;
 591         int done = 0;
 592         LIST_HEAD(hard_list);
 593
 594
 595         while (ok && !done) {
 596                 ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 597                 if (cp.struct_type != sizeof(cp)) {
 598                         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 599                                 "struct size %d instead of %d ok %d",
 600                                 cp.struct_type, (int)sizeof(cp), ok);
 601                         ok = 0;
 602                 }
 603
 604                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 605                         "Checkpoint read object %d parent %d type %d chunk %d ",
 606                         cp.obj_id, cp.parent_id, cp.variant_type,
 607                         cp.hdr_chunk);
 608
 609                 if (ok && cp.obj_id == ~0) {
 610                         done = 1;
 611                 } else if (ok) {
 612                         obj =
 613                             yaffs_find_or_create_by_number(dev, cp.obj_id,
 614                                                            cp.variant_type);
 615                         if (obj) {
 616                                 ok = yaffs2_checkpt_obj_to_obj(obj, &cp);
 617                                 if (!ok)
 618                                         break;
 619                                 if (obj->variant_type ==
 620                                         YAFFS_OBJECT_TYPE_FILE) {
 621                                         ok = yaffs2_rd_checkpt_tnodes(obj);
 622                                 } else if (obj->variant_type ==
 623                                         YAFFS_OBJECT_TYPE_HARDLINK) {
 624                                         list_add(&obj->hard_links, &hard_list);
 625                                 }
 626                         } else {
 627                                 ok = 0;
 628                         }
 629                 }
 630         }
 631
 632         if (ok)
 633                 yaffs_link_fixup(dev, &hard_list);
 634
 635         return ok ? 1 : 0;
 636 }
 637
 638 static int yaffs2_wr_checkpt_sum(struct yaffs_dev *dev)
 639 {
 640         u32 checkpt_sum;
 641         int ok;
 642
 643         yaffs2_get_checkpt_sum(dev, &checkpt_sum);
 644
 645         ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) ==
 646                 sizeof(checkpt_sum));
 647
 648         if (!ok)
 649                 return 0;
 650
 651         return 1;
 652 }
 653
 654 static int yaffs2_rd_checkpt_sum(struct yaffs_dev *dev)
 655 {
 656         u32 checkpt_sum0;
 657         u32 checkpt_sum1;
 658         int ok;
 659
 660         yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
 661
 662         ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) ==
 663                 sizeof(checkpt_sum1));
 664
 665         if (!ok)
 666                 return 0;
 667
 668         if (checkpt_sum0 != checkpt_sum1)
 669                 return 0;
 670
 671         return 1;
 672 }
 673
 674 static int yaffs2_wr_checkpt_data(struct yaffs_dev *dev)
 675 {
 676         int ok = 1;
 677
 678         if (!yaffs2_checkpt_required(dev)) {
 679                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 680                         "skipping checkpoint write");
 681                 ok = 0;
 682         }
 683
 684         if (ok)
 685                 ok = yaffs2_checkpt_open(dev, 1);
 686
 687         if (ok) {
 688                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 689                         "write checkpoint validity");
 690                 ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
 691         }
 692         if (ok) {
 693                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 694                         "write checkpoint device");
 695                 ok = yaffs2_wr_checkpt_dev(dev);
 696         }
 697         if (ok) {
 698                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 699                         "write checkpoint objects");
 700                 ok = yaffs2_wr_checkpt_objs(dev);
 701         }
 702         if (ok) {
 703                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 704                         "write checkpoint validity");
 705                 ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
 706         }
 707
 708         if (ok)
 709                 ok = yaffs2_wr_checkpt_sum(dev);
 710
 711         if (!yaffs_checkpt_close(dev))
 712                 ok = 0;
 713
 714         if (ok)
 715                 dev->is_checkpointed = 1;
 716         else
 717                 dev->is_checkpointed = 0;
 718
 719         return dev->is_checkpointed;
 720 }
 721
 722 static int yaffs2_rd_checkpt_data(struct yaffs_dev *dev)
 723 {
 724         int ok = 1;
 725
 726         if (!dev->param.is_yaffs2)
 727                 ok = 0;
 728
 729         if (ok && dev->param.skip_checkpt_rd) {
 730                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 731                         "skipping checkpoint read");
 732                 ok = 0;
 733         }
 734
 735         if (ok)
 736                 ok = yaffs2_checkpt_open(dev, 0); /* open for read */
 737
 738         if (ok) {
 739                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 740                         "read checkpoint validity");
 741                 ok = yaffs2_rd_checkpt_validity_marker(dev, 1);
 742         }
 743         if (ok) {
 744                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 745                         "read checkpoint device");
 746                 ok = yaffs2_rd_checkpt_dev(dev);
 747         }
 748         if (ok) {
 749                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 750                         "read checkpoint objects");
 751                 ok = yaffs2_rd_checkpt_objs(dev);
 752         }
 753         if (ok) {
 754                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 755                         "read checkpoint validity");
 756                 ok = yaffs2_rd_checkpt_validity_marker(dev, 0);
 757         }
 758
 759         if (ok) {
 760                 ok = yaffs2_rd_checkpt_sum(dev);
 761                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 762                         "read checkpoint checksum %d", ok);
 763         }
 764
 765         if (!yaffs_checkpt_close(dev))
 766                 ok = 0;
 767
 768         if (ok)
 769                 dev->is_checkpointed = 1;
 770         else
 771                 dev->is_checkpointed = 0;
 772
 773         return ok ? 1 : 0;
 774 }
 775
 776 void yaffs2_checkpt_invalidate(struct yaffs_dev *dev)
 777 {
 778         if (dev->is_checkpointed || dev->blocks_in_checkpt > 0) {
 779                 dev->is_checkpointed = 0;
 780                 yaffs2_checkpt_invalidate_stream(dev);
 781         }
 782         if (dev->param.sb_dirty_fn)
 783                 dev->param.sb_dirty_fn(dev);
 784 }
 785
 786 int yaffs_checkpoint_save(struct yaffs_dev *dev)
 787 {
 788         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 789                 "save entry: is_checkpointed %d",
 790                 dev->is_checkpointed);
 791
 792         yaffs_verify_objects(dev);
 793         yaffs_verify_blocks(dev);
 794         yaffs_verify_free_chunks(dev);
 795
 796         if (!dev->is_checkpointed) {
 797                 yaffs2_checkpt_invalidate(dev);
 798                 yaffs2_wr_checkpt_data(dev);
 799         }
 800
 801         yaffs_trace(YAFFS_TRACE_CHECKPOINT | YAFFS_TRACE_MOUNT,
 802                 "save exit: is_checkpointed %d",
 803                 dev->is_checkpointed);
 804
 805         return dev->is_checkpointed;
 806 }
 807
 808 int yaffs2_checkpt_restore(struct yaffs_dev *dev)
 809 {
 810         int retval;
 811
 812         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 813                 "restore entry: is_checkpointed %d",
 814                 dev->is_checkpointed);
 815
 816         retval = yaffs2_rd_checkpt_data(dev);
 817
 818         if (dev->is_checkpointed) {
 819                 yaffs_verify_objects(dev);
 820                 yaffs_verify_blocks(dev);
 821                 yaffs_verify_free_chunks(dev);
 822         }
 823
 824         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 825                 "restore exit: is_checkpointed %d",
 826                 dev->is_checkpointed);
 827
 828         return retval;
 829 }
 830
 831 int yaffs2_handle_hole(struct yaffs_obj *obj, loff_t new_size)
 832 {
 833         /* if new_size > old_file_size.
 834          * We're going to be writing a hole.
 835          * If the hole is small then write zeros otherwise write a start
 836          * of hole marker.
 837          */
 838         loff_t old_file_size;
 839         loff_t increase;
 840         int small_hole;
 841         int result = YAFFS_OK;
 842         struct yaffs_dev *dev = NULL;
 843         u8 *local_buffer = NULL;
 844         int small_increase_ok = 0;
 845
 846         if (!obj)
 847                 return YAFFS_FAIL;
 848
 849         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
 850                 return YAFFS_FAIL;
 851
 852         dev = obj->my_dev;
 853
 854         /* Bail out if not yaffs2 mode */
 855         if (!dev->param.is_yaffs2)
 856                 return YAFFS_OK;
 857
 858         old_file_size = obj->variant.file_variant.file_size;
 859
 860         if (new_size <= old_file_size)
 861                 return YAFFS_OK;
 862
 863         increase = new_size - old_file_size;
 864
 865         if (increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
 866             yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
 867                 small_hole = 1;
 868         else
 869                 small_hole = 0;
 870
 871         if (small_hole)
 872                 local_buffer = yaffs_get_temp_buffer(dev);
 873
 874         if (local_buffer) {
 875                 /* fill hole with zero bytes */
 876                 loff_t pos = old_file_size;
 877                 int this_write;
 878                 int written;
 879                 memset(local_buffer, 0, dev->data_bytes_per_chunk);
 880                 small_increase_ok = 1;
 881
 882                 while (increase > 0 && small_increase_ok) {
 883                         this_write = increase;
 884                         if (this_write > dev->data_bytes_per_chunk)
 885                                 this_write = dev->data_bytes_per_chunk;
 886                         written =
 887                             yaffs_do_file_wr(obj, local_buffer, pos, this_write,
 888                                              0);
 889                         if (written == this_write) {
 890                                 pos += this_write;
 891                                 increase -= this_write;
 892                         } else {
 893                                 small_increase_ok = 0;
 894                         }
 895                 }
 896
 897                 yaffs_release_temp_buffer(dev, local_buffer);
 898
 899                 /* If out of space then reverse any chunks we've added */
 900                 if (!small_increase_ok)
 901                         yaffs_resize_file_down(obj, old_file_size);
 902         }
 903
 904         if (!small_increase_ok &&
 905             obj->parent &&
 906             obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
 907             obj->parent->obj_id != YAFFS_OBJECTID_DELETED) {
 908                 /* Write a hole start header with the old file size */
 909                 yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
 910         }
 911
 912         return result;
 913 }
 914
 915 struct yaffs_block_index {
 916         int seq;
 917         int block;
 918 };
 919
 920 static int yaffs2_ybicmp(const void *a, const void *b)
 921 {
 922         int aseq = ((struct yaffs_block_index *)a)->seq;
 923         int bseq = ((struct yaffs_block_index *)b)->seq;
 924         int ablock = ((struct yaffs_block_index *)a)->block;
 925         int bblock = ((struct yaffs_block_index *)b)->block;
 926
 927         if (aseq == bseq)
 928                 return ablock - bblock;
 929
 930         return aseq - bseq;
 931 }
 932
 933 static inline int yaffs2_scan_chunk(struct yaffs_dev *dev,
 934                 struct yaffs_block_info *bi,
 935                 int blk, int chunk_in_block,
 936                 int *found_chunks,
 937                 u8 *chunk_data,
 938                 struct list_head *hard_list,
 939                 int summary_available)
 940 {
 941         struct yaffs_obj_hdr *oh;
 942         struct yaffs_obj *in;
 943         struct yaffs_obj *parent;
 944         int equiv_id;
 945         loff_t file_size;
 946         int is_shrink;
 947         int is_unlinked;
 948         struct yaffs_ext_tags tags;
 949         int alloc_failed = 0;
 950         int chunk = blk * dev->param.chunks_per_block + chunk_in_block;
 951         struct yaffs_file_var *file_var;
 952         struct yaffs_hardlink_var *hl_var;
 953         struct yaffs_symlink_var *sl_var;
 954
 955         if (summary_available) {
 956                 yaffs_summary_fetch(dev, &tags, chunk_in_block);
 957                 tags.seq_number = bi->seq_number;
 958         }
 959
 960         if (!summary_available || tags.obj_id == 0) {
 961                 yaffs_rd_chunk_tags_nand(dev, chunk, NULL, &tags);
 962                 dev->tags_used++;
 963         } else {
 964                 dev->summary_used++;
 965         }
 966
 967         /* Let's have a good look at this chunk... */
 968
 969         if (!tags.chunk_used) {
 970                 /* An unassigned chunk in the block.
 971                  * If there are used chunks after this one, then
 972                  * it is a chunk that was skipped due to failing
 973                  * the erased check. Just skip it so that it can
 974                  * be deleted.
 975                  * But, more typically, We get here when this is
 976                  * an unallocated chunk and his means that
 977                  * either the block is empty or this is the one
 978                  * being allocated from
 979                  */
 980
 981                 if (*found_chunks) {
 982                         /* This is a chunk that was skipped due
 983                          * to failing the erased check */
 984                 } else if (chunk_in_block == 0) {
 985                         /* We're looking at the first chunk in
 986                          * the block so the block is unused */
 987                         bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
 988                         dev->n_erased_blocks++;
 989                 } else {
 990                         if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
 991                             bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
 992                                 if (dev->seq_number == bi->seq_number) {
 993                                         /* Allocating from this block*/
 994                                         yaffs_trace(YAFFS_TRACE_SCAN,
 995                                             " Allocating from %d %d",
 996                                             blk, chunk_in_block);
 997
 998                                         bi->block_state =
 999                                                 YAFFS_BLOCK_STATE_ALLOCATING;
1000                                         dev->alloc_block = blk;
1001                                         dev->alloc_page = chunk_in_block;
1002                                         dev->alloc_block_finder = blk;
1003                                 } else {
1004                                         /* This is a partially written block
1005                                          * that is not the current
1006                                          * allocation block.
1007                                          */
1008                                         yaffs_trace(YAFFS_TRACE_SCAN,
1009                                                 "Partially written block %d detected. gc will fix this.",
1010                                                 blk);
1011                                 }
1012                         }
1013                 }
1014
1015                 dev->n_free_chunks++;
1016
1017         } else if (tags.ecc_result ==
1018                 YAFFS_ECC_RESULT_UNFIXED) {
1019                 yaffs_trace(YAFFS_TRACE_SCAN,
1020                         " Unfixed ECC in chunk(%d:%d), chunk ignored",
1021                         blk, chunk_in_block);
1022                         dev->n_free_chunks++;
1023         } else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
1024                    tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
1025                    tags.obj_id == YAFFS_OBJECTID_SUMMARY ||
1026                    (tags.chunk_id > 0 &&
1027                      tags.n_bytes > dev->data_bytes_per_chunk) ||
1028                    tags.seq_number != bi->seq_number) {
1029                 yaffs_trace(YAFFS_TRACE_SCAN,
1030                         "Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored",
1031                         blk, chunk_in_block, tags.obj_id,
1032                         tags.chunk_id, tags.n_bytes);
1033                 dev->n_free_chunks++;
1034         } else if (tags.chunk_id > 0) {
1035                 /* chunk_id > 0 so it is a data chunk... */
1036                 loff_t endpos;
1037                 loff_t chunk_base = (tags.chunk_id - 1) *
1038                                         dev->data_bytes_per_chunk;
1039
1040                 *found_chunks = 1;
1041
1042                 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
1043                 bi->pages_in_use++;
1044
1045                 in = yaffs_find_or_create_by_number(dev,
1046                                         tags.obj_id,
1047                                         YAFFS_OBJECT_TYPE_FILE);
1048                 if (!in)
1049                         /* Out of memory */
1050                         alloc_failed = 1;
1051
1052                 if (in &&
1053                     in->variant_type == YAFFS_OBJECT_TYPE_FILE &&
1054                     chunk_base < in->variant.file_variant.shrink_size) {
1055                         /* This has not been invalidated by
1056                          * a resize */
1057                         if (!yaffs_put_chunk_in_file(in, tags.chunk_id,
1058                                                                 chunk, -1))
1059                                 alloc_failed = 1;
1060
1061                         /* File size is calculated by looking at
1062                          * the data chunks if we have not
1063                          * seen an object header yet.
1064                          * Stop this practice once we find an
1065                          * object header.
1066                          */
1067                         endpos = chunk_base + tags.n_bytes;
1068
1069                         if (!in->valid &&
1070                             in->variant.file_variant.scanned_size < endpos) {
1071                                 in->variant.file_variant.
1072                                     scanned_size = endpos;
1073                                 in->variant.file_variant.
1074                                     file_size = endpos;
1075                         }
1076                 } else if (in) {
1077                         /* This chunk has been invalidated by a
1078                          * resize, or a past file deletion
1079                          * so delete the chunk*/
1080                         yaffs_chunk_del(dev, chunk, 1, __LINE__);
1081                 }
1082         } else {
1083                 /* chunk_id == 0, so it is an ObjectHeader.
1084                  * Thus, we read in the object header and make
1085                  * the object
1086                  */
1087                 *found_chunks = 1;
1088
1089                 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
1090                 bi->pages_in_use++;
1091
1092                 oh = NULL;
1093                 in = NULL;
1094
1095                 if (tags.extra_available) {
1096                         in = yaffs_find_or_create_by_number(dev,
1097                                         tags.obj_id,
1098                                         tags.extra_obj_type);
1099                         if (!in)
1100                                 alloc_failed = 1;
1101                 }
1102
1103                 if (!in ||
1104                     (!in->valid && dev->param.disable_lazy_load) ||
1105                     tags.extra_shadows ||
1106                     (!in->valid && (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1107                                  tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND))) {
1108
1109                         /* If we don't have  valid info then we
1110                          * need to read the chunk
1111                          * TODO In future we can probably defer
1112                          * reading the chunk and living with
1113                          * invalid data until needed.
1114                          */
1115
1116                         yaffs_rd_chunk_tags_nand(dev, chunk, chunk_data, NULL);
1117
1118                         oh = (struct yaffs_obj_hdr *)chunk_data;
1119
1120                         if (dev->param.inband_tags) {
1121                                 /* Fix up the header if they got
1122                                  * corrupted by inband tags */
1123                                 oh->shadows_obj =
1124                                     oh->inband_shadowed_obj_id;
1125                                 oh->is_shrink =
1126                                     oh->inband_is_shrink;
1127                         }
1128
1129                         if (!in) {
1130                                 in = yaffs_find_or_create_by_number(dev,
1131                                                         tags.obj_id, oh->type);
1132                                 if (!in)
1133                                         alloc_failed = 1;
1134                         }
1135                 }
1136
1137                 if (!in) {
1138                         /* TODO Hoosterman we have a problem! */
1139                         yaffs_trace(YAFFS_TRACE_ERROR,
1140                                 "yaffs tragedy: Could not make object for object  %d at chunk %d during scan",
1141                                 tags.obj_id, chunk);
1142                         return YAFFS_FAIL;
1143                 }
1144
1145                 if (in->valid) {
1146                         /* We have already filled this one.
1147                          * We have a duplicate that will be
1148                          * discarded, but we first have to suck
1149                          * out resize info if it is a file.
1150                          */
1151                         if ((in->variant_type == YAFFS_OBJECT_TYPE_FILE) &&
1152                                 ((oh && oh->type == YAFFS_OBJECT_TYPE_FILE) ||
1153                                  (tags.extra_available &&
1154                                   tags.extra_obj_type == YAFFS_OBJECT_TYPE_FILE)
1155                                 )) {
1156                                 loff_t this_size = (oh) ?
1157                                         yaffs_oh_to_size(oh) :
1158                                         tags.extra_file_size;
1159                                 u32 parent_obj_id = (oh) ?
1160                                         oh->parent_obj_id :
1161                                         tags.extra_parent_id;
1162
1163                                 is_shrink = (oh) ?
1164                                         oh->is_shrink :
1165                                         tags.extra_is_shrink;
1166
1167                                 /* If it is deleted (unlinked
1168                                  * at start also means deleted)
1169                                  * we treat the file size as
1170                                  * being zeroed at this point.
1171                                  */
1172                                 if (parent_obj_id == YAFFS_OBJECTID_DELETED ||
1173                                     parent_obj_id == YAFFS_OBJECTID_UNLINKED) {
1174                                         this_size = 0;
1175                                         is_shrink = 1;
1176                                 }
1177
1178                                 if (is_shrink &&
1179                                     in->variant.file_variant.shrink_size >
1180                                     this_size)
1181                                         in->variant.file_variant.shrink_size =
1182                                         this_size;
1183
1184                                 if (is_shrink)
1185                                         bi->has_shrink_hdr = 1;
1186                         }
1187                         /* Use existing - destroy this one. */
1188                         yaffs_chunk_del(dev, chunk, 1, __LINE__);
1189                 }
1190
1191                 if (!in->valid && in->variant_type !=
1192                     (oh ? oh->type : tags.extra_obj_type))
1193                         yaffs_trace(YAFFS_TRACE_ERROR,
1194                                 "yaffs tragedy: Bad object type, %d != %d, for object %d at chunk %d during scan",
1195                                 oh ? oh->type : tags.extra_obj_type,
1196                                 in->variant_type, tags.obj_id,
1197                                 chunk);
1198
1199                 if (!in->valid &&
1200                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1201                      tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND)) {
1202                         /* We only load some info, don't fiddle
1203                          * with directory structure */
1204                         in->valid = 1;
1205
1206                         if (oh) {
1207                                 in->yst_mode = oh->yst_mode;
1208                                 yaffs_load_attribs(in, oh);
1209                                 in->lazy_loaded = 0;
1210                         } else {
1211                                 in->lazy_loaded = 1;
1212                         }
1213                         in->hdr_chunk = chunk;
1214
1215                 } else if (!in->valid) {
1216                         /* we need to load this info */
1217                         in->valid = 1;
1218                         in->hdr_chunk = chunk;
1219                         if (oh) {
1220                                 in->variant_type = oh->type;
1221                                 in->yst_mode = oh->yst_mode;
1222                                 yaffs_load_attribs(in, oh);
1223
1224                                 if (oh->shadows_obj > 0)
1225                                         yaffs_handle_shadowed_obj(dev,
1226                                              oh->shadows_obj, 1);
1227
1228                                 yaffs_set_obj_name_from_oh(in, oh);
1229                                 parent = yaffs_find_or_create_by_number(dev,
1230                                                 oh->parent_obj_id,
1231                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
1232                                 file_size = yaffs_oh_to_size(oh);
1233                                 is_shrink = oh->is_shrink;
1234                                 equiv_id = oh->equiv_id;
1235                         } else {
1236                                 in->variant_type = tags.extra_obj_type;
1237                                 parent = yaffs_find_or_create_by_number(dev,
1238                                                 tags.extra_parent_id,
1239                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
1240                                 file_size = tags.extra_file_size;
1241                                 is_shrink = tags.extra_is_shrink;
1242                                 equiv_id = tags.extra_equiv_id;
1243                                 in->lazy_loaded = 1;
1244                         }
1245                         in->dirty = 0;
1246
1247                         if (!parent)
1248                                 alloc_failed = 1;
1249
1250                         /* directory stuff...
1251                          * hook up to parent
1252                          */
1253
1254                         if (parent &&
1255                             parent->variant_type == YAFFS_OBJECT_TYPE_UNKNOWN) {
1256                                 /* Set up as a directory */
1257                                 parent->variant_type =
1258                                         YAFFS_OBJECT_TYPE_DIRECTORY;
1259                                 INIT_LIST_HEAD(&parent->
1260                                                 variant.dir_variant.children);
1261                         } else if (!parent ||
1262                                    parent->variant_type !=
1263                                         YAFFS_OBJECT_TYPE_DIRECTORY) {
1264                                 /* Hoosterman, another problem....
1265                                  * Trying to use a non-directory as a directory
1266                                  */
1267
1268                                 yaffs_trace(YAFFS_TRACE_ERROR,
1269                                         "yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
1270                                         );
1271                                 parent = dev->lost_n_found;
1272                         }
1273                         yaffs_add_obj_to_dir(parent, in);
1274
1275                         is_unlinked = (parent == dev->del_dir) ||
1276                                         (parent == dev->unlinked_dir);
1277
1278                         if (is_shrink)
1279                                 /* Mark the block */
1280                                 bi->has_shrink_hdr = 1;
1281
1282                         /* Note re hardlinks.
1283                          * Since we might scan a hardlink before its equivalent
1284                          * object is scanned we put them all in a list.
1285                          * After scanning is complete, we should have all the
1286                          * objects, so we run through this list and fix up all
1287                          * the chains.
1288                          */
1289
1290                         switch (in->variant_type) {
1291                         case YAFFS_OBJECT_TYPE_UNKNOWN:
1292                                 /* Todo got a problem */
1293                                 break;
1294                         case YAFFS_OBJECT_TYPE_FILE:
1295                                 file_var = &in->variant.file_variant;
1296                                 if (file_var->scanned_size < file_size) {
1297                                         /* This covers the case where the file
1298                                          * size is greater than the data held.
1299                                          * This will happen if the file is
1300                                          * resized to be larger than its
1301                                          * current data extents.
1302                                          */
1303                                         file_var->file_size = file_size;
1304                                         file_var->scanned_size = file_size;
1305                                 }
1306
1307                                 if (file_var->shrink_size > file_size)
1308                                         file_var->shrink_size = file_size;
1309
1310                                 break;
1311                         case YAFFS_OBJECT_TYPE_HARDLINK:
1312                                 hl_var = &in->variant.hardlink_variant;
1313                                 if (!is_unlinked) {
1314                                         hl_var->equiv_id = equiv_id;
1315                                         list_add(&in->hard_links, hard_list);
1316                                 }
1317                                 break;
1318                         case YAFFS_OBJECT_TYPE_DIRECTORY:
1319                                 /* Do nothing */
1320                                 break;
1321                         case YAFFS_OBJECT_TYPE_SPECIAL:
1322                                 /* Do nothing */
1323                                 break;
1324                         case YAFFS_OBJECT_TYPE_SYMLINK:
1325                                 sl_var = &in->variant.symlink_variant;
1326                                 if (oh) {
1327                                         sl_var->alias =
1328                                             yaffs_clone_str(oh->alias);
1329                                         if (!sl_var->alias)
1330                                                 alloc_failed = 1;
1331                                 }
1332                                 break;
1333                         }
1334                 }
1335         }
1336         return alloc_failed ? YAFFS_FAIL : YAFFS_OK;
1337 }
1338
1339 int yaffs2_scan_backwards(struct yaffs_dev *dev)
1340 {
1341         int blk;
1342         int block_iter;
1343         int start_iter;
1344         int end_iter;
1345         int n_to_scan = 0;
1346         enum yaffs_block_state state;
1347         int c;
1348         LIST_HEAD(hard_list);
1349         struct yaffs_block_info *bi;
1350         u32 seq_number;
1351         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
1352         u8 *chunk_data;
1353         int found_chunks;
1354         int alloc_failed = 0;
1355         struct yaffs_block_index *block_index = NULL;
1356         int alt_block_index = 0;
1357         int summary_available;
1358
1359         yaffs_trace(YAFFS_TRACE_SCAN,
1360                 "yaffs2_scan_backwards starts  intstartblk %d intendblk %d...",
1361                 dev->internal_start_block, dev->internal_end_block);
1362
1363         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
1364
1365         block_index =
1366                 kmalloc(n_blocks * sizeof(struct yaffs_block_index), GFP_NOFS);
1367
1368         if (!block_index) {
1369                 block_index =
1370                     vmalloc(n_blocks * sizeof(struct yaffs_block_index));
1371                 alt_block_index = 1;
1372         }
1373
1374         if (!block_index) {
1375                 yaffs_trace(YAFFS_TRACE_SCAN,
1376                         "yaffs2_scan_backwards() could not allocate block index!"
1377                         );
1378                 return YAFFS_FAIL;
1379         }
1380
1381         dev->blocks_in_checkpt = 0;
1382
1383         chunk_data = yaffs_get_temp_buffer(dev);
1384
1385         /* Scan all the blocks to determine their state */
1386         bi = dev->block_info;
1387         for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
1388              blk++) {
1389                 yaffs_clear_chunk_bits(dev, blk);
1390                 bi->pages_in_use = 0;
1391                 bi->soft_del_pages = 0;
1392
1393                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
1394
1395                 bi->block_state = state;
1396                 bi->seq_number = seq_number;
1397
1398                 if (bi->seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA)
1399                         bi->block_state = YAFFS_BLOCK_STATE_CHECKPOINT;
1400                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
1401                         bi->block_state = YAFFS_BLOCK_STATE_DEAD;
1402
1403                 yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
1404                         "Block scanning block %d state %d seq %d",
1405                         blk, bi->block_state, seq_number);
1406
1407                 if (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT) {
1408                         dev->blocks_in_checkpt++;
1409
1410                 } else if (bi->block_state == YAFFS_BLOCK_STATE_DEAD) {
1411                         yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
1412                                 "block %d is bad", blk);
1413                 } else if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
1414                         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
1415                         dev->n_erased_blocks++;
1416                         dev->n_free_chunks += dev->param.chunks_per_block;
1417                 } else if (bi->block_state ==
1418                                 YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1419                         /* Determine the highest sequence number */
1420                         if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
1421                             seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
1422                                 block_index[n_to_scan].seq = seq_number;
1423                                 block_index[n_to_scan].block = blk;
1424                                 n_to_scan++;
1425                                 if (seq_number >= dev->seq_number)
1426                                         dev->seq_number = seq_number;
1427                         } else {
1428                                 /* TODO: Nasty sequence number! */
1429                                 yaffs_trace(YAFFS_TRACE_SCAN,
1430                                         "Block scanning block %d has bad sequence number %d",
1431                                         blk, seq_number);
1432                         }
1433                 }
1434                 bi++;
1435         }
1436
1437         yaffs_trace(YAFFS_TRACE_SCAN, "%d blocks to be sorted...", n_to_scan);
1438
1439         cond_resched();
1440
1441         /* Sort the blocks by sequence number */
1442         sort(block_index, n_to_scan, sizeof(struct yaffs_block_index),
1443                    yaffs2_ybicmp, NULL);
1444
1445         cond_resched();
1446
1447         yaffs_trace(YAFFS_TRACE_SCAN, "...done");
1448
1449         /* Now scan the blocks looking at the data. */
1450         start_iter = 0;
1451         end_iter = n_to_scan - 1;
1452         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "%d blocks to scan", n_to_scan);
1453
1454         /* For each block.... backwards */
1455         for (block_iter = end_iter;
1456              !alloc_failed && block_iter >= start_iter;
1457              block_iter--) {
1458                 /* Cooperative multitasking! This loop can run for so
1459                    long that watchdog timers expire. */
1460                 cond_resched();
1461
1462                 /* get the block to scan in the correct order */
1463                 blk = block_index[block_iter].block;
1464                 bi = yaffs_get_block_info(dev, blk);
1465
1466                 summary_available = yaffs_summary_read(dev, dev->sum_tags, blk);
1467
1468                 /* For each chunk in each block that needs scanning.... */
1469                 found_chunks = 0;
1470                 if (summary_available)
1471                         c = dev->chunks_per_summary - 1;
1472                 else
1473                         c = dev->param.chunks_per_block - 1;
1474
1475                 for (/* c is already initialised */;
1476                      !alloc_failed && c >= 0 &&
1477                      (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
1478                       bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING);
1479                       c--) {
1480                         /* Scan backwards...
1481                          * Read the tags and decide what to do
1482                          */
1483                         if (yaffs2_scan_chunk(dev, bi, blk, c,
1484                                         &found_chunks, chunk_data,
1485                                         &hard_list, summary_available) ==
1486                                         YAFFS_FAIL)
1487                                 alloc_failed = 1;
1488                 }
1489
1490                 if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1491                         /* If we got this far while scanning, then the block
1492                          * is fully allocated. */
1493                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
1494                 }
1495
1496                 /* Now let's see if it was dirty */
1497                 if (bi->pages_in_use == 0 &&
1498                     !bi->has_shrink_hdr &&
1499                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
1500                         yaffs_block_became_dirty(dev, blk);
1501                 }
1502         }
1503
1504         yaffs_skip_rest_of_block(dev);
1505
1506         if (alt_block_index)
1507                 vfree(block_index);
1508         else
1509                 kfree(block_index);
1510
1511         /* Ok, we've done all the scanning.
1512          * Fix up the hard link chains.
1513          * We have scanned all the objects, now it's time to add these
1514          * hardlinks.
1515          */
1516         yaffs_link_fixup(dev, &hard_list);
1517
1518         yaffs_release_temp_buffer(dev, chunk_data);
1519
1520         if (alloc_failed)
1521                 return YAFFS_FAIL;
1522
1523         yaffs_trace(YAFFS_TRACE_SCAN, "yaffs2_scan_backwards ends");
1524
1525         return YAFFS_OK;
1526 }