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 #include "yaffs_endian.h"
  25
  26 /*
  27  * Checkpoints are really no benefit on very small partitions.
  28  *
  29  * To save space on small partitions don't bother with checkpoints unless
  30  * the partition is at least this big.
  31  */
  32 #define YAFFS_CHECKPOINT_MIN_BLOCKS 60
  33 #define YAFFS_SMALL_HOLE_THRESHOLD 4
  34
  35 /*
  36  * Oldest Dirty Sequence Number handling.
  37  */
  38
  39 /* yaffs_calc_oldest_dirty_seq()
  40  * yaffs2_find_oldest_dirty_seq()
  41  * Calculate the oldest dirty sequence number if we don't know it.
  42  */
  43 void yaffs_calc_oldest_dirty_seq(struct yaffs_dev *dev)
  44 {
  45         int i;
  46         unsigned seq;
  47         unsigned block_no = 0;
  48         struct yaffs_block_info *b;
  49
  50         if (!dev->param.is_yaffs2)
  51                 return;
  52
  53         /* Find the oldest dirty sequence number. */
  54         seq = dev->seq_number + 1;
  55         b = dev->block_info;
  56         for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
  57                 if (b->block_state == YAFFS_BLOCK_STATE_FULL &&
  58                     (b->pages_in_use - b->soft_del_pages) <
  59                     dev->param.chunks_per_block &&
  60                     b->seq_number < seq) {
  61                         seq = b->seq_number;
  62                         block_no = i;
  63                 }
  64                 b++;
  65         }
  66
  67         if (block_no) {
  68                 dev->oldest_dirty_seq = seq;
  69                 dev->oldest_dirty_block = block_no;
  70         }
  71 }
  72
  73 void yaffs2_find_oldest_dirty_seq(struct yaffs_dev *dev)
  74 {
  75         if (!dev->param.is_yaffs2)
  76                 return;
  77
  78         if (!dev->oldest_dirty_seq)
  79                 yaffs_calc_oldest_dirty_seq(dev);
  80 }
  81
  82 /*
  83  * yaffs_clear_oldest_dirty_seq()
  84  * Called when a block is erased or marked bad. (ie. when its seq_number
  85  * becomes invalid). If the value matches the oldest then we clear
  86  * dev->oldest_dirty_seq to force its recomputation.
  87  */
  88 void yaffs2_clear_oldest_dirty_seq(struct yaffs_dev *dev,
  89                                    struct yaffs_block_info *bi)
  90 {
  91
  92         if (!dev->param.is_yaffs2)
  93                 return;
  94
  95         if (!bi || bi->seq_number == dev->oldest_dirty_seq) {
  96                 dev->oldest_dirty_seq = 0;
  97                 dev->oldest_dirty_block = 0;
  98         }
  99 }
 100
 101 /*
 102  * yaffs2_update_oldest_dirty_seq()
 103  * Update the oldest dirty sequence number whenever we dirty a block.
 104  * Only do this if the oldest_dirty_seq is actually being tracked.
 105  */
 106 void yaffs2_update_oldest_dirty_seq(struct yaffs_dev *dev, unsigned block_no,
 107                                     struct yaffs_block_info *bi)
 108 {
 109         if (!dev->param.is_yaffs2)
 110                 return;
 111
 112         if (dev->oldest_dirty_seq) {
 113                 if (dev->oldest_dirty_seq > bi->seq_number) {
 114                         dev->oldest_dirty_seq = bi->seq_number;
 115                         dev->oldest_dirty_block = block_no;
 116                 }
 117         }
 118 }
 119
 120 int yaffs_block_ok_for_gc(struct yaffs_dev *dev, struct yaffs_block_info *bi)
 121 {
 122
 123         if (!dev->param.is_yaffs2)
 124                 return 1;       /* disqualification only applies to yaffs2. */
 125
 126         if (!bi->has_shrink_hdr)
 127                 return 1;       /* can gc */
 128
 129         yaffs2_find_oldest_dirty_seq(dev);
 130
 131         /* Can't do gc of this block if there are any blocks older than this
 132          * one that have discarded pages.
 133          */
 134         return (bi->seq_number <= dev->oldest_dirty_seq);
 135 }
 136
 137 /*
 138  * yaffs2_find_refresh_block()
 139  * periodically finds the oldest full block by sequence number for refreshing.
 140  * Only for yaffs2.
 141  */
 142 u32 yaffs2_find_refresh_block(struct yaffs_dev *dev)
 143 {
 144         u32 b;
 145         u32 oldest = 0;
 146         u32 oldest_seq = 0;
 147         struct yaffs_block_info *bi;
 148
 149         if (!dev->param.is_yaffs2)
 150                 return oldest;
 151
 152         /*
 153          * If refresh period < 10 then refreshing is disabled.
 154          */
 155         if (dev->param.refresh_period < 10)
 156                 return oldest;
 157
 158         /*
 159          * Fix broken values.
 160          */
 161         if (dev->refresh_skip > dev->param.refresh_period)
 162                 dev->refresh_skip = dev->param.refresh_period;
 163
 164         if (dev->refresh_skip > 0)
 165                 return oldest;
 166
 167         /*
 168          * Refresh skip is now zero.
 169          * We'll do a refresh this time around....
 170          * Update the refresh skip and find the oldest block.
 171          */
 172         dev->refresh_skip = dev->param.refresh_period;
 173         dev->refresh_count++;
 174         bi = dev->block_info;
 175         for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
 176
 177                 if (bi->block_state == YAFFS_BLOCK_STATE_FULL) {
 178
 179                         if (oldest < 1 || bi->seq_number < oldest_seq) {
 180                                 oldest = b;
 181                                 oldest_seq = bi->seq_number;
 182                         }
 183                 }
 184                 bi++;
 185         }
 186
 187         if (oldest > 0) {
 188                 yaffs_trace(YAFFS_TRACE_GC,
 189                         "GC refresh count %d selected block %d with seq_number %d",
 190                         dev->refresh_count, oldest, oldest_seq);
 191         }
 192
 193         return oldest;
 194 }
 195
 196 int yaffs2_checkpt_required(struct yaffs_dev *dev)
 197 {
 198         int nblocks;
 199
 200         if (!dev->param.is_yaffs2)
 201                 return 0;
 202
 203         nblocks = dev->internal_end_block - dev->internal_start_block + 1;
 204
 205         return !dev->param.skip_checkpt_wr &&
 206             !dev->read_only && (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
 207 }
 208
 209 int yaffs_calc_checkpt_blocks_required(struct yaffs_dev *dev)
 210 {
 211         int retval;
 212         int n_bytes = 0;
 213         int n_blocks;
 214         int dev_blocks;
 215
 216         if (!dev->param.is_yaffs2)
 217                 return 0;
 218
 219         if (!dev->checkpoint_blocks_required && yaffs2_checkpt_required(dev)) {
 220                 /* Not a valid value so recalculate */
 221                 dev_blocks = dev->param.end_block - dev->param.start_block + 1;
 222                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 223                 n_bytes += sizeof(struct yaffs_checkpt_dev);
 224                 n_bytes += dev_blocks * sizeof(struct yaffs_block_info);
 225                 n_bytes += dev_blocks * dev->chunk_bit_stride;
 226                 n_bytes +=
 227                     (sizeof(struct yaffs_checkpt_obj) + sizeof(u32)) *
 228                     dev->n_obj;
 229                 n_bytes += (dev->tnode_size + sizeof(u32)) * dev->n_tnodes;
 230                 n_bytes += sizeof(struct yaffs_checkpt_validity);
 231                 n_bytes += sizeof(u32); /* checksum */
 232
 233                 /* Round up and add 2 blocks to allow for some bad blocks,
 234                  * so add 3 */
 235
 236                 n_blocks =
 237                     (n_bytes /
 238                      (dev->data_bytes_per_chunk *
 239                       dev->param.chunks_per_block)) + 3;
 240
 241                 dev->checkpoint_blocks_required = n_blocks;
 242         }
 243
 244         retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
 245         if (retval < 0)
 246                 retval = 0;
 247         return retval;
 248 }
 249
 250 /*--------------------- Checkpointing --------------------*/
 251
 252 static void yaffs2_do_endian_validity_marker(struct yaffs_dev *dev,
 253                                              struct yaffs_checkpt_validity *v)
 254 {
 255
 256         if (!dev->swap_endian)
 257                 return;
 258         v->struct_type = swap_s32(v->struct_type);
 259         v->magic = swap_u32(v->magic);
 260         v->version = swap_u32(v->version);
 261         v->head = swap_u32(v->head);
 262 }
 263
 264 static int yaffs2_wr_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 265 {
 266         struct yaffs_checkpt_validity cp;
 267
 268         memset(&cp, 0, sizeof(cp));
 269
 270         cp.struct_type = sizeof(cp);
 271         cp.magic = YAFFS_MAGIC;
 272         cp.version = YAFFS_CHECKPOINT_VERSION;
 273         cp.head = (head) ? 1 : 0;
 274
 275         yaffs2_do_endian_validity_marker(dev, &cp);
 276
 277         return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ? 1 : 0;
 278 }
 279
 280 static int yaffs2_rd_checkpt_validity_marker(struct yaffs_dev *dev, int head)
 281 {
 282         struct yaffs_checkpt_validity cp;
 283         int ok;
 284
 285         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 286         yaffs2_do_endian_validity_marker(dev, &cp);
 287
 288         if (ok)
 289                 ok = (cp.struct_type == sizeof(cp)) &&
 290                     (cp.magic == YAFFS_MAGIC) &&
 291                     (cp.version == YAFFS_CHECKPOINT_VERSION) &&
 292                     (cp.head == ((head) ? 1 : 0));
 293         return ok ? 1 : 0;
 294 }
 295
 296 static void yaffs2_dev_to_checkpt_dev(struct yaffs_checkpt_dev *cp,
 297                                       struct yaffs_dev *dev)
 298 {
 299         cp->struct_type = sizeof(*cp);
 300
 301         cp->n_erased_blocks = dev->n_erased_blocks;
 302         cp->alloc_block = dev->alloc_block;
 303         cp->alloc_page = dev->alloc_page;
 304         cp->n_free_chunks = dev->n_free_chunks;
 305
 306         cp->n_deleted_files = dev->n_deleted_files;
 307         cp->n_unlinked_files = dev->n_unlinked_files;
 308         cp->n_bg_deletions = dev->n_bg_deletions;
 309         cp->seq_number = dev->seq_number;
 310
 311 }
 312
 313 static void yaffs_checkpt_dev_to_dev(struct yaffs_dev *dev,
 314                                      struct yaffs_checkpt_dev *cp)
 315 {
 316         dev->n_erased_blocks = cp->n_erased_blocks;
 317         dev->alloc_block = cp->alloc_block;
 318         dev->alloc_page = cp->alloc_page;
 319         dev->n_free_chunks = cp->n_free_chunks;
 320
 321         dev->n_deleted_files = cp->n_deleted_files;
 322         dev->n_unlinked_files = cp->n_unlinked_files;
 323         dev->n_bg_deletions = cp->n_bg_deletions;
 324         dev->seq_number = cp->seq_number;
 325 }
 326
 327 static void yaffs2_do_endian_checkpt_dev(struct yaffs_dev *dev,
 328                                      struct yaffs_checkpt_dev *cp)
 329 {
 330         if (!dev->swap_endian)
 331                 return;
 332         cp->struct_type = swap_s32(cp->struct_type);
 333         cp->n_erased_blocks = swap_s32(cp->n_erased_blocks);
 334         cp->alloc_block = swap_s32(cp->alloc_block);
 335         cp->alloc_page = swap_u32(cp->alloc_page);
 336         cp->n_free_chunks = swap_s32(cp->n_free_chunks);
 337         cp->n_deleted_files = swap_s32(cp->n_deleted_files);
 338         cp->n_unlinked_files = swap_s32(cp->n_unlinked_files);
 339         cp->n_bg_deletions = swap_s32(cp->n_bg_deletions);
 340 }
 341
 342 static int yaffs2_wr_checkpt_dev(struct yaffs_dev *dev)
 343 {
 344         struct yaffs_checkpt_dev cp;
 345         u32 n_bytes;
 346         u32 n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
 347         int ok;
 348         int i;
 349         union yaffs_block_info_union bu;
 350
 351         /* Write device runtime values */
 352         yaffs2_dev_to_checkpt_dev(&cp, dev);
 353         yaffs2_do_endian_checkpt_dev(dev, &cp);
 354
 355         ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 356         if (!ok)
 357                 return 0;
 358
 359         /* Write block info. */
 360         if (!dev->swap_endian) {
 361                 n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 362                 ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) == n_bytes);
 363         } else {
 364                 /*
 365                  * Need to swap the endianisms. We can't do this in place
 366                  * since that would damage live data,
 367                  * so write one block info at a time using a copy.
 368                  */
 369                 for (i = 0; i < n_blocks && ok; i++) {
 370                         bu.bi = dev->block_info[i];
 371                         bu.as_u32[0] = swap_u32(bu.as_u32[0]);
 372                         bu.as_u32[1] = swap_u32(bu.as_u32[1]);
 373                         ok = (yaffs2_checkpt_wr(dev, &bu, sizeof(bu)) == sizeof(bu));
 374                 }
 375         }
 376
 377         if (!ok)
 378                 return 0;
 379
 380         /*
 381          * Write chunk bits. Chunk bits are in bytes so
 382          * no endian conversion is needed.
 383          */
 384         n_bytes = n_blocks * dev->chunk_bit_stride;
 385         ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) == n_bytes);
 386
 387         return ok ? 1 : 0;
 388 }
 389
 390 static int yaffs2_rd_checkpt_dev(struct yaffs_dev *dev)
 391 {
 392         struct yaffs_checkpt_dev cp;
 393         u32 n_bytes;
 394         u32 n_blocks =
 395             (dev->internal_end_block - dev->internal_start_block + 1);
 396         int ok;
 397
 398         ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 399         if (!ok)
 400                 return 0;
 401         yaffs2_do_endian_checkpt_dev(dev, &cp);
 402
 403         if (cp.struct_type != sizeof(cp))
 404                 return 0;
 405
 406         yaffs_checkpt_dev_to_dev(dev, &cp);
 407
 408         n_bytes = n_blocks * sizeof(struct yaffs_block_info);
 409
 410         ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
 411
 412         if (!ok)
 413                 return 0;
 414
 415         if (dev->swap_endian) {
 416                 /* The block info can just be handled as a list of u32s. */
 417                 u32 *as_u32 = (u32 *) dev->block_info;
 418                 u32 n_u32s = n_bytes/sizeof(u32);
 419                 u32 i;
 420
 421                 for (i=0; i < n_u32s; i++)
 422                         as_u32[i] = swap_u32(as_u32[i]);
 423         }
 424
 425         n_bytes = n_blocks * dev->chunk_bit_stride;
 426
 427         ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
 428
 429
 430         return ok ? 1 : 0;
 431 }
 432
 433
 434 static void yaffs2_checkpt_obj_bit_assign(struct yaffs_checkpt_obj *cp,
 435                                           int bit_offset,
 436                                           int bit_width,
 437                                           u32 value)
 438 {
 439         u32 and_mask;
 440
 441         and_mask = ((1<<bit_width)-1) << bit_offset;
 442
 443         cp->bit_field &= ~and_mask;
 444         cp->bit_field |= ((value << bit_offset) & and_mask);
 445 }
 446
 447 static u32 yaffs2_checkpt_obj_bit_get(struct yaffs_checkpt_obj *cp,
 448                                       int bit_offset,
 449                                       int bit_width)
 450 {
 451         u32 and_mask;
 452
 453         and_mask = ((1<<bit_width)-1);
 454
 455         return (cp->bit_field >> bit_offset) & and_mask;
 456 }
 457
 458 static void yaffs2_obj_checkpt_obj(struct yaffs_checkpt_obj *cp,
 459                                    struct yaffs_obj *obj)
 460 {
 461         cp->obj_id = obj->obj_id;
 462         cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
 463         cp->hdr_chunk = obj->hdr_chunk;
 464
 465         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_VARIANT_BITS, obj->variant_type);
 466         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_DELETED_BITS, obj->deleted);
 467         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_SOFT_DEL_BITS, obj->soft_del);
 468         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_UNLINKED_BITS, obj->unlinked);
 469         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_FAKE_BITS, obj->fake);
 470         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_RENAME_ALLOWED_BITS, obj->rename_allowed);
 471         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_UNLINK_ALLOWED_BITS, obj->unlink_allowed);
 472         yaffs2_checkpt_obj_bit_assign(cp, CHECKPOINT_SERIAL_BITS, obj->serial);
 473
 474         cp->n_data_chunks = obj->n_data_chunks;
 475
 476         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
 477                 cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
 478         else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
 479                 cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
 480 }
 481
 482 static int yaffs2_checkpt_obj_to_obj(struct yaffs_obj *obj,
 483                                      struct yaffs_checkpt_obj *cp)
 484 {
 485         struct yaffs_obj *parent;
 486         u32 cp_variant_type = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_VARIANT_BITS);
 487
 488         if (obj->variant_type != cp_variant_type) {
 489                 yaffs_trace(YAFFS_TRACE_ERROR,
 490                         "Checkpoint read object %d type %d chunk %d does not match existing object type %d",
 491                         cp->obj_id, cp_variant_type, cp->hdr_chunk,
 492                         obj->variant_type);
 493                 return 0;
 494         }
 495
 496         obj->obj_id = cp->obj_id;
 497
 498         if (cp->parent_id)
 499                 parent = yaffs_find_or_create_by_number(obj->my_dev,
 500                                                 cp->parent_id,
 501                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
 502         else
 503                 parent = NULL;
 504
 505         if (parent) {
 506                 if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
 507                         yaffs_trace(YAFFS_TRACE_ALWAYS,
 508                                 "Checkpoint read object %d parent %d type %d chunk %d Parent type, %d, not directory",
 509                                 cp->obj_id, cp->parent_id,
 510                                 cp_variant_type, cp->hdr_chunk,
 511                                 parent->variant_type);
 512                         return 0;
 513                 }
 514                 yaffs_add_obj_to_dir(parent, obj);
 515         }
 516
 517         obj->hdr_chunk = cp->hdr_chunk;
 518
 519         obj->variant_type = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_VARIANT_BITS);
 520         obj->deleted = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_DELETED_BITS);
 521         obj->soft_del = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_SOFT_DEL_BITS);
 522         obj->unlinked = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_UNLINKED_BITS);
 523         obj->fake = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_FAKE_BITS);
 524         obj->rename_allowed = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_RENAME_ALLOWED_BITS);
 525         obj->unlink_allowed = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_UNLINK_ALLOWED_BITS);
 526         obj->serial = yaffs2_checkpt_obj_bit_get(cp, CHECKPOINT_SERIAL_BITS);
 527
 528         obj->n_data_chunks = cp->n_data_chunks;
 529
 530         if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
 531                 obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
 532                 obj->variant.file_variant.stored_size = cp->size_or_equiv_obj;
 533         } else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
 534                 obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
 535         }
 536         if (obj->hdr_chunk > 0)
 537                 obj->lazy_loaded = 1;
 538         return 1;
 539 }
 540
 541 static void yaffs2_do_endian_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
 542 {
 543         int i;
 544         u32 *as_u32 = (u32 *)tn;
 545         int tnode_size_u32 = dev->tnode_size / sizeof(u32);
 546
 547         if (!dev->swap_endian)
 548                 return;
 549         /* Swap all the tnode data as u32s to fix endianisms. */
 550         for (i = 0; i<tnode_size_u32; i++)
 551                 as_u32[i] = swap_u32(as_u32[i]);
 552 }
 553
 554 struct yaffs_tnode *yaffs2_do_endian_tnode_copy(struct yaffs_dev *dev,
 555                                                struct yaffs_tnode *tn)
 556 {
 557         if (!dev->swap_endian)
 558                 return tn;
 559
 560         memcpy(dev->tn_swap_buffer, tn, dev->tnode_size);
 561         tn = dev->tn_swap_buffer;
 562
 563         yaffs2_do_endian_tnode(dev, tn);
 564
 565         return tn;
 566 }
 567
 568 static int yaffs2_checkpt_tnode_worker(struct yaffs_obj *in,
 569                                        struct yaffs_tnode *tn, u32 level,
 570                                        int chunk_offset)
 571 {
 572         int i;
 573         struct yaffs_dev *dev = in->my_dev;
 574         int ok = 1;
 575         u32 base_offset;
 576
 577         if (!tn)
 578                 return 1;
 579
 580         if (level > 0) {
 581                 for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
 582                         if (!tn->internal[i])
 583                                 continue;
 584                         ok = yaffs2_checkpt_tnode_worker(in,
 585                                  tn->internal[i],
 586                                  level - 1,
 587                                  (chunk_offset <<
 588                                   YAFFS_TNODES_INTERNAL_BITS) + i);
 589                 }
 590                 return ok;
 591         }
 592
 593         /* Level 0 tnode */
 594         base_offset = chunk_offset << YAFFS_TNODES_LEVEL0_BITS;
 595         yaffs_do_endian_u32(dev, &base_offset);
 596
 597         ok = (yaffs2_checkpt_wr(dev, &base_offset, sizeof(base_offset)) ==
 598                         sizeof(base_offset));
 599         if (ok) {
 600                 /*
 601                  * NB Can't do an in-place endian swizzle since that would
 602                  * damage current tnode data.
 603                  * If a tnode endian conversion is required we do a copy.
 604                  */
 605                 tn = yaffs2_do_endian_tnode_copy(dev, tn);
 606                 ok = (yaffs2_checkpt_wr(dev, tn, dev->tnode_size) ==
 607                         dev->tnode_size);
 608         }
 609         return ok;
 610 }
 611
 612 static int yaffs2_wr_checkpt_tnodes(struct yaffs_obj *obj)
 613 {
 614         u32 end_marker = ~0;
 615         int ok = 1;
 616
 617         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
 618                 return ok;
 619
 620         ok = yaffs2_checkpt_tnode_worker(obj,
 621                                          obj->variant.file_variant.top,
 622                                          obj->variant.file_variant.
 623                                          top_level, 0);
 624         if (ok)
 625                 ok = (yaffs2_checkpt_wr(obj->my_dev, &end_marker,
 626                                 sizeof(end_marker)) == sizeof(end_marker));
 627
 628         return ok ? 1 : 0;
 629 }
 630
 631 static int yaffs2_rd_checkpt_tnodes(struct yaffs_obj *obj)
 632 {
 633         u32 base_chunk;
 634         int ok = 1;
 635         struct yaffs_dev *dev = obj->my_dev;
 636         struct yaffs_file_var *file_stuct_ptr = &obj->variant.file_variant;
 637         struct yaffs_tnode *tn;
 638         int nread = 0;
 639
 640         ok = (yaffs2_checkpt_rd(dev, &base_chunk, sizeof(base_chunk)) ==
 641               sizeof(base_chunk));
 642
 643         yaffs_do_endian_u32(dev, &base_chunk);
 644
 645         while (ok && (~base_chunk)) {
 646                 nread++;
 647                 /* Read level 0 tnode */
 648
 649                 tn = yaffs_get_tnode(dev);
 650                 if (tn) {
 651                         ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) ==
 652                                 dev->tnode_size);
 653                         yaffs2_do_endian_tnode(dev, tn);
 654                 }
 655                 else
 656                         ok = 0;
 657
 658                 if (tn && ok)
 659                         ok = yaffs_add_find_tnode_0(dev,
 660                                                     file_stuct_ptr,
 661                                                     base_chunk, tn) ? 1 : 0;
 662
 663                 if (ok) {
 664                         ok = (yaffs2_checkpt_rd
 665                               (dev, &base_chunk,
 666                                sizeof(base_chunk)) == sizeof(base_chunk));
 667                         yaffs_do_endian_u32(dev, &base_chunk);
 668                 }
 669
 670         }
 671
 672         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 673                 "Checkpoint read tnodes %d records, last %d. ok %d",
 674                 nread, base_chunk, ok);
 675
 676         return ok ? 1 : 0;
 677 }
 678
 679
 680 static void yaffs2_do_endian_checkpt_obj(struct yaffs_dev *dev,
 681                                          struct yaffs_checkpt_obj *cp)
 682 {
 683         if (!dev->swap_endian)
 684                 return;
 685         cp->struct_type = swap_s32(cp->struct_type);
 686         cp->obj_id = swap_u32(cp->obj_id);
 687         cp->parent_id = swap_u32(cp->parent_id);
 688         cp->hdr_chunk = swap_s32(cp->hdr_chunk);
 689         cp->bit_field = swap_u32(cp->bit_field);
 690         cp->n_data_chunks = swap_s32(cp->n_data_chunks);
 691         cp->size_or_equiv_obj = swap_loff_t(cp->size_or_equiv_obj);
 692 }
 693
 694 static int yaffs2_wr_checkpt_objs(struct yaffs_dev *dev)
 695 {
 696         struct yaffs_obj *obj;
 697         struct yaffs_checkpt_obj cp;
 698         int i;
 699         int ok = 1;
 700         struct list_head *lh;
 701         u32 cp_variant_type;
 702
 703         /* Iterate through the objects in each hash entry,
 704          * dumping them to the checkpointing stream.
 705          */
 706
 707         for (i = 0; ok && i < YAFFS_NOBJECT_BUCKETS; i++) {
 708                 list_for_each(lh, &dev->obj_bucket[i].list) {
 709                         obj = list_entry(lh, struct yaffs_obj, hash_link);
 710                         if (!obj->defered_free) {
 711                                 yaffs2_obj_checkpt_obj(&cp, obj);
 712                                 cp.struct_type = sizeof(cp);
 713                                 cp_variant_type = yaffs2_checkpt_obj_bit_get(
 714                                                 &cp, CHECKPOINT_VARIANT_BITS);
 715                                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 716                                         "Checkpoint write object %d parent %d type %d chunk %d obj addr %p",
 717                                         cp.obj_id, cp.parent_id,
 718                                         cp_variant_type, cp.hdr_chunk, obj);
 719
 720                                 yaffs2_do_endian_checkpt_obj (dev, &cp);
 721                                 ok = (yaffs2_checkpt_wr(dev, &cp,
 722                                                 sizeof(cp)) == sizeof(cp));
 723
 724                                 if (ok &&
 725                                         obj->variant_type ==
 726                                         YAFFS_OBJECT_TYPE_FILE)
 727                                         ok = yaffs2_wr_checkpt_tnodes(obj);
 728                         }
 729                 }
 730         }
 731
 732         /* Dump end of list */
 733         memset(&cp, 0xff, sizeof(struct yaffs_checkpt_obj));
 734         cp.struct_type = sizeof(cp);
 735         yaffs2_do_endian_checkpt_obj (dev, &cp);
 736
 737         if (ok)
 738                 ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
 739
 740         return ok ? 1 : 0;
 741 }
 742
 743 static int yaffs2_rd_checkpt_objs(struct yaffs_dev *dev)
 744 {
 745         struct yaffs_obj *obj;
 746         struct yaffs_checkpt_obj cp;
 747         int ok = 1;
 748         int done = 0;
 749         u32 cp_variant_type;
 750         LIST_HEAD(hard_list);
 751
 752
 753         while (ok && !done) {
 754                 ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
 755                 yaffs2_do_endian_checkpt_obj (dev, &cp);
 756
 757                 if (cp.struct_type != sizeof(cp)) {
 758                         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 759                                 "struct size %d instead of %d ok %d",
 760                                 cp.struct_type, (int)sizeof(cp), ok);
 761                         ok = 0;
 762                 }
 763
 764                 cp_variant_type = yaffs2_checkpt_obj_bit_get(
 765                                                 &cp, CHECKPOINT_VARIANT_BITS);
 766                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 767                         "Checkpoint read object %d parent %d type %d chunk %d ",
 768                         cp.obj_id, cp.parent_id, cp_variant_type,
 769                         cp.hdr_chunk);
 770
 771                 if (ok && cp.obj_id == ~0) {
 772                         done = 1;
 773                 } else if (ok) {
 774                         obj =
 775                             yaffs_find_or_create_by_number(dev, cp.obj_id,
 776                                                            cp_variant_type);
 777                         if (obj) {
 778                                 ok = yaffs2_checkpt_obj_to_obj(obj, &cp);
 779                                 if (!ok)
 780                                         break;
 781                                 if (obj->variant_type ==
 782                                         YAFFS_OBJECT_TYPE_FILE) {
 783                                         ok = yaffs2_rd_checkpt_tnodes(obj);
 784                                 } else if (obj->variant_type ==
 785                                         YAFFS_OBJECT_TYPE_HARDLINK) {
 786                                         list_add(&obj->hard_links, &hard_list);
 787                                 }
 788                         } else {
 789                                 ok = 0;
 790                         }
 791                 }
 792         }
 793
 794         if (ok)
 795                 yaffs_link_fixup(dev, &hard_list);
 796
 797         return ok ? 1 : 0;
 798 }
 799
 800 static int yaffs2_wr_checkpt_sum(struct yaffs_dev *dev)
 801 {
 802         u32 checkpt_sum;
 803         int ok;
 804
 805         yaffs2_get_checkpt_sum(dev, &checkpt_sum);
 806
 807         yaffs_do_endian_u32(dev, &checkpt_sum);
 808
 809         ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) ==
 810                 sizeof(checkpt_sum));
 811
 812         if (!ok)
 813                 return 0;
 814
 815         return 1;
 816 }
 817
 818 static int yaffs2_rd_checkpt_sum(struct yaffs_dev *dev)
 819 {
 820         u32 checkpt_sum0;
 821         u32 checkpt_sum1;
 822         int ok;
 823
 824         yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
 825
 826         ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) ==
 827                 sizeof(checkpt_sum1));
 828
 829         if (!ok)
 830                 return 0;
 831         yaffs_do_endian_u32(dev, &checkpt_sum1);
 832
 833         if (checkpt_sum0 != checkpt_sum1)
 834                 return 0;
 835
 836         return 1;
 837 }
 838
 839 static int yaffs2_wr_checkpt_data(struct yaffs_dev *dev)
 840 {
 841         int ok = 1;
 842
 843         if (!yaffs2_checkpt_required(dev)) {
 844                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 845                         "skipping checkpoint write");
 846                 ok = 0;
 847         }
 848
 849         if (ok)
 850                 ok = yaffs2_checkpt_open(dev, 1);
 851
 852         if (ok) {
 853                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 854                         "write checkpoint validity");
 855                 ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
 856         }
 857         if (ok) {
 858                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 859                         "write checkpoint device");
 860                 ok = yaffs2_wr_checkpt_dev(dev);
 861         }
 862         if (ok) {
 863                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 864                         "write checkpoint objects");
 865                 ok = yaffs2_wr_checkpt_objs(dev);
 866         }
 867         if (ok) {
 868                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 869                         "write checkpoint validity");
 870                 ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
 871         }
 872
 873         if (ok)
 874                 ok = yaffs2_wr_checkpt_sum(dev);
 875
 876         if (!yaffs_checkpt_close(dev))
 877                 ok = 0;
 878
 879         if (ok)
 880                 dev->is_checkpointed = 1;
 881         else
 882                 dev->is_checkpointed = 0;
 883
 884         return dev->is_checkpointed;
 885 }
 886
 887 static int yaffs2_rd_checkpt_data(struct yaffs_dev *dev)
 888 {
 889         int ok = 1;
 890
 891         if (!dev->param.is_yaffs2)
 892                 ok = 0;
 893
 894         if (ok && dev->param.skip_checkpt_rd) {
 895                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 896                         "skipping checkpoint read");
 897                 ok = 0;
 898         }
 899
 900         if (ok)
 901                 ok = yaffs2_checkpt_open(dev, 0); /* open for read */
 902
 903         if (ok) {
 904                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 905                         "read checkpoint validity");
 906                 ok = yaffs2_rd_checkpt_validity_marker(dev, 1);
 907         }
 908         if (ok) {
 909                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 910                         "read checkpoint device");
 911                 ok = yaffs2_rd_checkpt_dev(dev);
 912         }
 913         if (ok) {
 914                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 915                         "read checkpoint objects");
 916                 ok = yaffs2_rd_checkpt_objs(dev);
 917         }
 918         if (ok) {
 919                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 920                         "read checkpoint validity");
 921                 ok = yaffs2_rd_checkpt_validity_marker(dev, 0);
 922         }
 923
 924         if (ok) {
 925                 ok = yaffs2_rd_checkpt_sum(dev);
 926                 yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 927                         "read checkpoint checksum %d", ok);
 928         }
 929
 930         if (!yaffs_checkpt_close(dev))
 931                 ok = 0;
 932
 933         if (ok)
 934                 dev->is_checkpointed = 1;
 935         else
 936                 dev->is_checkpointed = 0;
 937
 938         return ok ? 1 : 0;
 939 }
 940
 941 void yaffs2_checkpt_invalidate(struct yaffs_dev *dev)
 942 {
 943         if (dev->is_checkpointed || dev->blocks_in_checkpt > 0) {
 944                 dev->is_checkpointed = 0;
 945                 yaffs2_checkpt_invalidate_stream(dev);
 946         }
 947         if (dev->param.sb_dirty_fn)
 948                 dev->param.sb_dirty_fn(dev);
 949 }
 950
 951 int yaffs_checkpoint_save(struct yaffs_dev *dev)
 952 {
 953         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 954                 "save entry: is_checkpointed %d",
 955                 dev->is_checkpointed);
 956
 957         yaffs_verify_objects(dev);
 958         yaffs_verify_blocks(dev);
 959         yaffs_verify_free_chunks(dev);
 960
 961         if (!dev->is_checkpointed) {
 962                 yaffs2_checkpt_invalidate(dev);
 963                 yaffs2_wr_checkpt_data(dev);
 964         }
 965
 966         yaffs_trace(YAFFS_TRACE_CHECKPOINT | YAFFS_TRACE_MOUNT,
 967                 "save exit: is_checkpointed %d",
 968                 dev->is_checkpointed);
 969
 970         return dev->is_checkpointed;
 971 }
 972
 973 int yaffs2_checkpt_restore(struct yaffs_dev *dev)
 974 {
 975         int retval;
 976
 977         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 978                 "restore entry: is_checkpointed %d",
 979                 dev->is_checkpointed);
 980
 981         retval = yaffs2_rd_checkpt_data(dev);
 982
 983         if (dev->is_checkpointed) {
 984                 yaffs_verify_objects(dev);
 985                 yaffs_verify_blocks(dev);
 986                 yaffs_verify_free_chunks(dev);
 987         }
 988
 989         yaffs_trace(YAFFS_TRACE_CHECKPOINT,
 990                 "restore exit: is_checkpointed %d",
 991                 dev->is_checkpointed);
 992
 993         return retval;
 994 }
 995
 996 /* End of checkpointing */
 997
 998 /* Hole handling logic for truncate past end of file */
 999
1000 int yaffs2_handle_hole(struct yaffs_obj *obj, loff_t new_size)
1001 {
1002         /* if new_size > old_file_size.
1003          * We're going to be writing a hole.
1004          * If the hole is small then write zeros otherwise write a start
1005          * of hole marker.
1006          */
1007         loff_t old_file_size;
1008         loff_t increase;
1009         int small_hole;
1010         int result = YAFFS_OK;
1011         struct yaffs_dev *dev = NULL;
1012         u8 *local_buffer = NULL;
1013         int small_increase_ok = 0;
1014
1015         if (!obj)
1016                 return YAFFS_FAIL;
1017
1018         if (obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
1019                 return YAFFS_FAIL;
1020
1021         dev = obj->my_dev;
1022
1023         /* Bail out if not yaffs2 mode */
1024         if (!dev->param.is_yaffs2)
1025                 return YAFFS_OK;
1026
1027         old_file_size = obj->variant.file_variant.file_size;
1028
1029         if (new_size <= old_file_size)
1030                 return YAFFS_OK;
1031
1032         increase = new_size - old_file_size;
1033
1034         if (increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
1035             yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
1036                 small_hole = 1;
1037         else
1038                 small_hole = 0;
1039
1040         if (small_hole)
1041                 local_buffer = yaffs_get_temp_buffer(dev);
1042
1043         if (local_buffer) {
1044                 /* fill hole with zero bytes */
1045                 loff_t pos = old_file_size;
1046                 int this_write;
1047                 int written;
1048                 memset(local_buffer, 0, dev->data_bytes_per_chunk);
1049                 small_increase_ok = 1;
1050
1051                 while (increase > 0 && small_increase_ok) {
1052                         this_write = increase;
1053                         if (this_write > dev->data_bytes_per_chunk)
1054                                 this_write = dev->data_bytes_per_chunk;
1055                         written =
1056                             yaffs_do_file_wr(obj, local_buffer, pos, this_write,
1057                                              0);
1058                         if (written == this_write) {
1059                                 pos += this_write;
1060                                 increase -= this_write;
1061                         } else {
1062                                 small_increase_ok = 0;
1063                         }
1064                 }
1065
1066                 yaffs_release_temp_buffer(dev, local_buffer);
1067
1068                 /* If out of space then reverse any chunks we've added */
1069                 if (!small_increase_ok)
1070                         yaffs_resize_file_down(obj, old_file_size);
1071         }
1072
1073         if (!small_increase_ok &&
1074             obj->parent &&
1075             obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
1076             obj->parent->obj_id != YAFFS_OBJECTID_DELETED) {
1077                 /* Write a hole start header with the old file size */
1078                 yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
1079         }
1080
1081         return result;
1082 }
1083
1084 /* Yaffs2 scanning */
1085
1086 struct yaffs_block_index {
1087         int seq;
1088         int block;
1089 };
1090
1091 static int yaffs2_ybicmp(const void *a, const void *b)
1092 {
1093         int aseq = ((struct yaffs_block_index *)a)->seq;
1094         int bseq = ((struct yaffs_block_index *)b)->seq;
1095         int ablock = ((struct yaffs_block_index *)a)->block;
1096         int bblock = ((struct yaffs_block_index *)b)->block;
1097
1098         if (aseq == bseq)
1099                 return ablock - bblock;
1100
1101         return aseq - bseq;
1102 }
1103
1104 static inline int yaffs2_scan_chunk(struct yaffs_dev *dev,
1105                 struct yaffs_block_info *bi,
1106                 int blk, int chunk_in_block,
1107                 int *found_chunks,
1108                 u8 *chunk_data,
1109                 struct list_head *hard_list,
1110                 int summary_available)
1111 {
1112         struct yaffs_obj_hdr *oh;
1113         struct yaffs_obj *in;
1114         struct yaffs_obj *parent;
1115         int equiv_id;
1116         loff_t file_size;
1117         int is_shrink;
1118         int is_unlinked;
1119         struct yaffs_ext_tags tags;
1120         int result;
1121         int alloc_failed = 0;
1122         int chunk = blk * dev->param.chunks_per_block + chunk_in_block;
1123         struct yaffs_file_var *file_var;
1124         struct yaffs_hardlink_var *hl_var;
1125         struct yaffs_symlink_var *sl_var;
1126
1127         if (summary_available) {
1128                 result = yaffs_summary_fetch(dev, &tags, chunk_in_block);
1129                 tags.seq_number = bi->seq_number;
1130         }
1131
1132         if (!summary_available || tags.obj_id == 0) {
1133                 result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL, &tags);
1134                 dev->tags_used++;
1135         } else {
1136                 dev->summary_used++;
1137         }
1138
1139         /* Let's have a good look at this chunk... */
1140
1141         if (!tags.chunk_used) {
1142                 /* An unassigned chunk in the block.
1143                  * If there are used chunks after this one, then
1144                  * it is a chunk that was skipped due to failing
1145                  * the erased check. Just skip it so that it can
1146                  * be deleted.
1147                  * But, more typically, We get here when this is
1148                  * an unallocated chunk and his means that
1149                  * either the block is empty or this is the one
1150                  * being allocated from
1151                  */
1152
1153                 if (*found_chunks) {
1154                         /* This is a chunk that was skipped due
1155                          * to failing the erased check */
1156                 } else if (chunk_in_block == 0) {
1157                         /* We're looking at the first chunk in
1158                          * the block so the block is unused */
1159                         bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
1160                         dev->n_erased_blocks++;
1161                 } else {
1162                         if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
1163                             bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
1164                                 if (dev->seq_number == bi->seq_number) {
1165                                         /* Allocating from this block*/
1166                                         yaffs_trace(YAFFS_TRACE_SCAN,
1167                                             " Allocating from %d %d",
1168                                             blk, chunk_in_block);
1169
1170                                         bi->block_state =
1171                                                 YAFFS_BLOCK_STATE_ALLOCATING;
1172                                         dev->alloc_block = blk;
1173                                         dev->alloc_page = chunk_in_block;
1174                                         dev->alloc_block_finder = blk;
1175                                 } else {
1176                                         /* This is a partially written block
1177                                          * that is not the current
1178                                          * allocation block.
1179                                          */
1180                                         yaffs_trace(YAFFS_TRACE_SCAN,
1181                                                 "Partially written block %d detected. gc will fix this.",
1182                                                 blk);
1183                                 }
1184                         }
1185                 }
1186
1187                 dev->n_free_chunks++;
1188
1189         } else if (tags.ecc_result ==
1190                 YAFFS_ECC_RESULT_UNFIXED) {
1191                 yaffs_trace(YAFFS_TRACE_SCAN,
1192                         " Unfixed ECC in chunk(%d:%d), chunk ignored",
1193                         blk, chunk_in_block);
1194                         dev->n_free_chunks++;
1195         } else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
1196                    tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
1197                    tags.obj_id == YAFFS_OBJECTID_SUMMARY ||
1198                    (tags.chunk_id > 0 &&
1199                      tags.n_bytes > dev->data_bytes_per_chunk) ||
1200                    tags.seq_number != bi->seq_number) {
1201                 yaffs_trace(YAFFS_TRACE_SCAN,
1202                         "Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored",
1203                         blk, chunk_in_block, tags.obj_id,
1204                         tags.chunk_id, tags.n_bytes);
1205                 dev->n_free_chunks++;
1206         } else if (tags.chunk_id > 0) {
1207                 /* chunk_id > 0 so it is a data chunk... */
1208                 loff_t endpos;
1209                 loff_t chunk_base = (tags.chunk_id - 1) *
1210                                         dev->data_bytes_per_chunk;
1211
1212                 *found_chunks = 1;
1213
1214                 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
1215                 bi->pages_in_use++;
1216
1217                 in = yaffs_find_or_create_by_number(dev,
1218                                         tags.obj_id,
1219                                         YAFFS_OBJECT_TYPE_FILE);
1220                 if (!in)
1221                         /* Out of memory */
1222                         alloc_failed = 1;
1223
1224                 if (in &&
1225                     in->variant_type == YAFFS_OBJECT_TYPE_FILE &&
1226                     chunk_base < in->variant.file_variant.shrink_size) {
1227                         /* This has not been invalidated by
1228                          * a resize */
1229                         if (!yaffs_put_chunk_in_file(in, tags.chunk_id,
1230                                                                 chunk, -1))
1231                                 alloc_failed = 1;
1232
1233                         /* File size is calculated by looking at
1234                          * the data chunks if we have not
1235                          * seen an object header yet.
1236                          * Stop this practice once we find an
1237                          * object header.
1238                          */
1239                         endpos = chunk_base + tags.n_bytes;
1240
1241                         if (!in->valid &&
1242                             in->variant.file_variant.stored_size < endpos) {
1243                                 in->variant.file_variant.
1244                                     stored_size = endpos;
1245                                 in->variant.file_variant.
1246                                     file_size = endpos;
1247                         }
1248                 } else if (in) {
1249                         /* This chunk has been invalidated by a
1250                          * resize, or a past file deletion
1251                          * so delete the chunk*/
1252                         yaffs_chunk_del(dev, chunk, 1, __LINE__);
1253                 }
1254         } else {
1255                 /* chunk_id == 0, so it is an ObjectHeader.
1256                  * Thus, we read in the object header and make
1257                  * the object
1258                  */
1259                 *found_chunks = 1;
1260
1261                 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
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.obj_id,
1270                                         tags.extra_obj_type);
1271                         if (!in)
1272                                 alloc_failed = 1;
1273                 }
1274
1275                 if (!in ||
1276                     (!in->valid && dev->param.disable_lazy_load) ||
1277                     tags.extra_shadows ||
1278                     (!in->valid && (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1279                                  tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND))) {
1280
1281                         /* If we don't have  valid info then we
1282                          * need to read the chunk
1283                          * TODO In future we can probably defer
1284                          * reading the chunk and living with
1285                          * invalid data until needed.
1286                          */
1287
1288                         result = yaffs_rd_chunk_tags_nand(dev,
1289                                                   chunk,
1290                                                   chunk_data,
1291                                                   NULL);
1292
1293                         oh = (struct yaffs_obj_hdr *)chunk_data;
1294
1295                         yaffs_do_endian_oh(dev, oh);
1296
1297                         if (dev->param.inband_tags) {
1298                                 /* Fix up the header if they got
1299                                  * corrupted by inband tags */
1300                                 oh->shadows_obj =
1301                                     oh->inband_shadowed_obj_id;
1302                                 oh->is_shrink =
1303                                     oh->inband_is_shrink;
1304                         }
1305
1306                         if (!in) {
1307                                 in = yaffs_find_or_create_by_number(dev,
1308                                                         tags.obj_id, oh->type);
1309                                 if (!in)
1310                                         alloc_failed = 1;
1311                         }
1312                 }
1313
1314                 if (!in) {
1315                         /* TODO Hoosterman we have a problem! */
1316                         yaffs_trace(YAFFS_TRACE_ERROR,
1317                                 "yaffs tragedy: Could not make object for object  %d at chunk %d during scan",
1318                                 tags.obj_id, chunk);
1319                         return YAFFS_FAIL;
1320                 }
1321
1322                 if (in->valid) {
1323                         /* We have already filled this one.
1324                          * We have a duplicate that will be
1325                          * discarded, but we first have to suck
1326                          * out resize info if it is a file.
1327                          */
1328                         if ((in->variant_type == YAFFS_OBJECT_TYPE_FILE) &&
1329                                 ((oh && oh->type == YAFFS_OBJECT_TYPE_FILE) ||
1330                                  (tags.extra_available &&
1331                                   tags.extra_obj_type == YAFFS_OBJECT_TYPE_FILE)
1332                                 )) {
1333                                 loff_t this_size = (oh) ?
1334                                         yaffs_oh_to_size(dev, oh, 0) :
1335                                         tags.extra_file_size;
1336                                 u32 parent_obj_id = (oh) ?
1337                                         oh->parent_obj_id :
1338                                         tags.extra_parent_id;
1339
1340                                 is_shrink = (oh) ?
1341                                         oh->is_shrink :
1342                                         tags.extra_is_shrink;
1343
1344                                 /* If it is deleted (unlinked
1345                                  * at start also means deleted)
1346                                  * we treat the file size as
1347                                  * being zeroed at this point.
1348                                  */
1349                                 if (parent_obj_id == YAFFS_OBJECTID_DELETED ||
1350                                     parent_obj_id == YAFFS_OBJECTID_UNLINKED) {
1351                                         this_size = 0;
1352                                         is_shrink = 1;
1353                                 }
1354
1355                                 if (is_shrink &&
1356                                     in->variant.file_variant.shrink_size >
1357                                     this_size)
1358                                         in->variant.file_variant.shrink_size =
1359                                         this_size;
1360
1361                                 if (is_shrink)
1362                                         bi->has_shrink_hdr = 1;
1363                         }
1364                         /* Use existing - destroy this one. */
1365                         yaffs_chunk_del(dev, chunk, 1, __LINE__);
1366                 }
1367
1368                 if (!in->valid && in->variant_type !=
1369                     (oh ? oh->type : tags.extra_obj_type)) {
1370                         yaffs_trace(YAFFS_TRACE_ERROR,
1371                                 "yaffs tragedy: Bad type, %d != %d, for object %d at chunk %d during scan",
1372                                 oh ? oh->type : tags.extra_obj_type,
1373                                 in->variant_type, tags.obj_id,
1374                                 chunk);
1375                         in = yaffs_retype_obj(in, oh ? oh->type : tags.extra_obj_type);
1376                 }
1377
1378                 if (!in->valid &&
1379                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
1380                      tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND)) {
1381                         /* We only load some info, don't fiddle
1382                          * with directory structure */
1383                         in->valid = 1;
1384
1385                         if (oh) {
1386                                 in->yst_mode = oh->yst_mode;
1387                                 yaffs_load_attribs(in, oh);
1388                                 in->lazy_loaded = 0;
1389                         } else {
1390                                 in->lazy_loaded = 1;
1391                         }
1392                         in->hdr_chunk = chunk;
1393
1394                 } else if (!in->valid) {
1395                         /* we need to load this info */
1396                         in->valid = 1;
1397                         in->hdr_chunk = chunk;
1398                         if (oh) {
1399                                 in->variant_type = oh->type;
1400                                 in->yst_mode = oh->yst_mode;
1401                                 yaffs_load_attribs(in, oh);
1402
1403                                 if (oh->shadows_obj > 0)
1404                                         yaffs_handle_shadowed_obj(dev,
1405                                              oh->shadows_obj, 1);
1406
1407                                 yaffs_set_obj_name_from_oh(in, oh);
1408                                 parent = yaffs_find_or_create_by_number(dev,
1409                                                 oh->parent_obj_id,
1410                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
1411                                 file_size = yaffs_oh_to_size(dev, oh, 0);
1412                                 is_shrink = oh->is_shrink;
1413                                 equiv_id = oh->equiv_id;
1414                         } else {
1415                                 in->variant_type = tags.extra_obj_type;
1416                                 parent = yaffs_find_or_create_by_number(dev,
1417                                                 tags.extra_parent_id,
1418                                                 YAFFS_OBJECT_TYPE_DIRECTORY);
1419                                 file_size = tags.extra_file_size;
1420                                 is_shrink = tags.extra_is_shrink;
1421                                 equiv_id = tags.extra_equiv_id;
1422                                 in->lazy_loaded = 1;
1423                         }
1424                         in->dirty = 0;
1425
1426                         if (!parent)
1427                                 alloc_failed = 1;
1428
1429                         /* directory stuff...
1430                          * hook up to parent
1431                          */
1432
1433                         if (parent &&
1434                             parent->variant_type == YAFFS_OBJECT_TYPE_UNKNOWN) {
1435                                 /* Set up as a directory */
1436                                 parent->variant_type =
1437                                         YAFFS_OBJECT_TYPE_DIRECTORY;
1438                                 INIT_LIST_HEAD(&parent->
1439                                                 variant.dir_variant.children);
1440                         } else if (!parent ||
1441                                    parent->variant_type !=
1442                                         YAFFS_OBJECT_TYPE_DIRECTORY) {
1443                                 /* Hoosterman, another problem....
1444                                  * Trying to use a non-directory as a directory
1445                                  */
1446
1447                                 yaffs_trace(YAFFS_TRACE_ERROR,
1448                                         "yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
1449                                         );
1450                                 parent = dev->lost_n_found;
1451                         }
1452                         yaffs_add_obj_to_dir(parent, in);
1453
1454                         is_unlinked = (parent == dev->del_dir) ||
1455                                         (parent == dev->unlinked_dir);
1456
1457                         if (is_shrink)
1458                                 /* Mark the block */
1459                                 bi->has_shrink_hdr = 1;
1460
1461                         /* Note re hardlinks.
1462                          * Since we might scan a hardlink before its equivalent
1463                          * object is scanned we put them all in a list.
1464                          * After scanning is complete, we should have all the
1465                          * objects, so we run through this list and fix up all
1466                          * the chains.
1467                          */
1468
1469                         switch (in->variant_type) {
1470                         case YAFFS_OBJECT_TYPE_UNKNOWN:
1471                                 /* Todo got a problem */
1472                                 break;
1473                         case YAFFS_OBJECT_TYPE_FILE:
1474                                 file_var = &in->variant.file_variant;
1475                                 if (file_var->stored_size < file_size) {
1476                                         /* This covers the case where the file
1477                                          * size is greater than the data held.
1478                                          * This will happen if the file is
1479                                          * resized to be larger than its
1480                                          * current data extents.
1481                                          */
1482                                         file_var->file_size = file_size;
1483                                         file_var->stored_size = file_size;
1484                                 }
1485
1486                                 if (file_var->shrink_size > file_size)
1487                                         file_var->shrink_size = file_size;
1488
1489                                 break;
1490                         case YAFFS_OBJECT_TYPE_HARDLINK:
1491                                 hl_var = &in->variant.hardlink_variant;
1492                                 if (!is_unlinked) {
1493                                         hl_var->equiv_id = equiv_id;
1494                                         list_add(&in->hard_links, hard_list);
1495                                 }
1496                                 break;
1497                         case YAFFS_OBJECT_TYPE_DIRECTORY:
1498                                 /* Do nothing */
1499                                 break;
1500                         case YAFFS_OBJECT_TYPE_SPECIAL:
1501                                 /* Do nothing */
1502                                 break;
1503                         case YAFFS_OBJECT_TYPE_SYMLINK:
1504                                 sl_var = &in->variant.symlink_variant;
1505                                 if (oh) {
1506                                         sl_var->alias =
1507                                             yaffs_clone_str(oh->alias);
1508                                         if (!sl_var->alias)
1509                                                 alloc_failed = 1;
1510                                 }
1511                                 break;
1512                         }
1513                 }
1514         }
1515         return alloc_failed ? YAFFS_FAIL : YAFFS_OK;
1516 }
1517
1518 int yaffs2_scan_backwards(struct yaffs_dev *dev)
1519 {
1520         int blk;
1521         int block_iter;
1522         int start_iter;
1523         int end_iter;
1524         int n_to_scan = 0;
1525         enum yaffs_block_state state;
1526         int c;
1527         LIST_HEAD(hard_list);
1528         struct yaffs_block_info *bi;
1529         u32 seq_number;
1530         int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;
1531         u8 *chunk_data;
1532         int found_chunks;
1533         int alloc_failed = 0;
1534         struct yaffs_block_index *block_index = NULL;
1535         int alt_block_index = 0;
1536         int summary_available;
1537
1538         yaffs_trace(YAFFS_TRACE_SCAN,
1539                 "yaffs2_scan_backwards starts  intstartblk %d intendblk %d...",
1540                 dev->internal_start_block, dev->internal_end_block);
1541
1542         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
1543
1544         block_index =
1545                 kmalloc(n_blocks * sizeof(struct yaffs_block_index), GFP_NOFS);
1546
1547         if (!block_index) {
1548                 block_index =
1549                     vmalloc(n_blocks * sizeof(struct yaffs_block_index));
1550                 alt_block_index = 1;
1551         }
1552
1553         if (!block_index) {
1554                 yaffs_trace(YAFFS_TRACE_SCAN,
1555                         "yaffs2_scan_backwards() could not allocate block index!"
1556                         );
1557                 return YAFFS_FAIL;
1558         }
1559
1560         dev->blocks_in_checkpt = 0;
1561
1562         chunk_data = yaffs_get_temp_buffer(dev);
1563
1564         /* Scan all the blocks to determine their state */
1565         bi = dev->block_info;
1566         for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
1567              blk++) {
1568                 yaffs_clear_chunk_bits(dev, blk);
1569                 bi->pages_in_use = 0;
1570                 bi->soft_del_pages = 0;
1571
1572                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
1573
1574                 bi->block_state = state;
1575                 bi->seq_number = seq_number;
1576
1577                 if (bi->seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA)
1578                         bi->block_state = YAFFS_BLOCK_STATE_CHECKPOINT;
1579                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
1580                         bi->block_state = YAFFS_BLOCK_STATE_DEAD;
1581
1582                 yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
1583                         "Block scanning block %d state %d seq %d",
1584                         blk, bi->block_state, seq_number);
1585
1586                 if (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT) {
1587                         dev->blocks_in_checkpt++;
1588
1589                 } else if (bi->block_state == YAFFS_BLOCK_STATE_DEAD) {
1590                         yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
1591                                 "block %d is bad", blk);
1592                 } else if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
1593                         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
1594                         dev->n_erased_blocks++;
1595                         dev->n_free_chunks += dev->param.chunks_per_block;
1596                 } else if (bi->block_state ==
1597                                 YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1598                         /* Determine the highest sequence number */
1599                         if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
1600                             seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
1601                                 block_index[n_to_scan].seq = seq_number;
1602                                 block_index[n_to_scan].block = blk;
1603                                 n_to_scan++;
1604                                 if (seq_number >= dev->seq_number)
1605                                         dev->seq_number = seq_number;
1606                         } else {
1607                                 /* TODO: Nasty sequence number! */
1608                                 yaffs_trace(YAFFS_TRACE_SCAN,
1609                                         "Block scanning block %d has bad sequence number %d",
1610                                         blk, seq_number);
1611                         }
1612                 }
1613                 bi++;
1614         }
1615
1616         yaffs_trace(YAFFS_TRACE_ALWAYS, "%d blocks to be sorted...", n_to_scan);
1617
1618         cond_resched();
1619
1620         /* Sort the blocks by sequence number */
1621         sort(block_index, n_to_scan, sizeof(struct yaffs_block_index),
1622                    yaffs2_ybicmp, NULL);
1623
1624         cond_resched();
1625
1626         yaffs_trace(YAFFS_TRACE_SCAN, "...done");
1627
1628         /* Now scan the blocks looking at the data. */
1629         start_iter = 0;
1630         end_iter = n_to_scan - 1;
1631         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "%d blocks to scan", n_to_scan);
1632
1633         /* For each block.... backwards */
1634         for (block_iter = end_iter;
1635              !alloc_failed && block_iter >= start_iter;
1636              block_iter--) {
1637                 /* Cooperative multitasking! This loop can run for so
1638                    long that watchdog timers expire. */
1639                 cond_resched();
1640
1641                 /* get the block to scan in the correct order */
1642                 blk = block_index[block_iter].block;
1643                 bi = yaffs_get_block_info(dev, blk);
1644
1645                 summary_available = yaffs_summary_read(dev, dev->sum_tags, blk);
1646
1647                 /* For each chunk in each block that needs scanning.... */
1648                 found_chunks = 0;
1649                 if (summary_available)
1650                         c = dev->chunks_per_summary - 1;
1651                 else
1652                         c = dev->param.chunks_per_block - 1;
1653
1654                 for (/* c is already initialised */;
1655                      !alloc_failed && c >= 0 &&
1656                      (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
1657                       bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING);
1658                       c--) {
1659                         /* Scan backwards...
1660                          * Read the tags and decide what to do
1661                          */
1662                         if (yaffs2_scan_chunk(dev, bi, blk, c,
1663                                         &found_chunks, chunk_data,
1664                                         &hard_list, summary_available) ==
1665                                         YAFFS_FAIL)
1666                                 alloc_failed = 1;
1667                 }
1668
1669                 if (bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN) {
1670                         /* If we got this far while scanning, then the block
1671                          * is fully allocated. */
1672                         bi->block_state = YAFFS_BLOCK_STATE_FULL;
1673                 }
1674
1675                 /* Now let's see if it was dirty */
1676                 if (bi->pages_in_use == 0 &&
1677                     !bi->has_shrink_hdr &&
1678                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
1679                         yaffs_block_became_dirty(dev, blk);
1680                 }
1681         }
1682
1683         yaffs_skip_rest_of_block(dev);
1684
1685         if (alt_block_index)
1686                 vfree(block_index);
1687         else
1688                 kfree(block_index);
1689
1690         /* Ok, we've done all the scanning.
1691          * Fix up the hard link chains.
1692          * We have scanned all the objects, now it's time to add these
1693          * hardlinks.
1694          */
1695         yaffs_link_fixup(dev, &hard_list);
1696
1697         yaffs_release_temp_buffer(dev, chunk_data);
1698
1699         if (alloc_failed)
1700                 return YAFFS_FAIL;
1701
1702         yaffs_trace(YAFFS_TRACE_SCAN, "yaffs2_scan_backwards ends");
1703
1704         return YAFFS_OK;
1705 }