yaffs_yaffs1.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2010 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include "yaffs_yaffs1.h"
  15 #include "yportenv.h"
  16 #include "yaffs_trace.h"
  17 #include "yaffs_bitmap.h"
  18 #include "yaffs_getblockinfo.h"
  19 #include "yaffs_nand.h"
  20 #include "yaffs_attribs.h"
  21
  22 int yaffs1_scan(struct yaffs_dev *dev)
  23 {
  24         struct yaffs_ext_tags tags;
  25         int blk;
  26         int result;
  27
  28         int chunk;
  29         int c;
  30         int deleted;
  31         enum yaffs_block_state state;
  32         struct yaffs_obj *hard_list = NULL;
  33         struct yaffs_block_info *bi;
  34         u32 seq_number;
  35         struct yaffs_obj_hdr *oh;
  36         struct yaffs_obj *in;
  37         struct yaffs_obj *parent;
  38
  39         int alloc_failed = 0;
  40
  41         struct yaffs_shadow_fixer *shadow_fixers = NULL;
  42
  43
  44         u8 *chunk_data;
  45
  46
  47
  48         T(YAFFS_TRACE_SCAN,
  49           (TSTR("yaffs1_scan starts  intstartblk %d intendblk %d..." TENDSTR),
  50            dev->internal_start_block, dev->internal_end_block));
  51
  52         chunk_data = yaffs_get_temp_buffer(dev, __LINE__);
  53
  54         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
  55
  56         /* Scan all the blocks to determine their state */
  57         bi = dev->block_info;
  58         for (blk = dev->internal_start_block; blk <= dev->internal_end_block; blk++) {
  59                 yaffs_clear_chunk_bits(dev, blk);
  60                 bi->pages_in_use = 0;
  61                 bi->soft_del_pages = 0;
  62
  63                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
  64
  65                 bi->block_state = state;
  66                 bi->seq_number = seq_number;
  67
  68                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
  69                         bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
  70
  71                 T(YAFFS_TRACE_SCAN_DEBUG,
  72                   (TSTR("Block scanning block %d state %d seq %d" TENDSTR), blk,
  73                    state, seq_number));
  74
  75                 if (state == YAFFS_BLOCK_STATE_DEAD) {
  76                         T(YAFFS_TRACE_BAD_BLOCKS,
  77                           (TSTR("block %d is bad" TENDSTR), blk));
  78                 } else if (state == YAFFS_BLOCK_STATE_EMPTY) {
  79                         T(YAFFS_TRACE_SCAN_DEBUG,
  80                           (TSTR("Block empty " TENDSTR)));
  81                         dev->n_erased_blocks++;
  82                         dev->n_free_chunks += dev->param.chunks_per_block;
  83                 }
  84                 bi++;
  85         }
  86
  87         /* For each block.... */
  88         for (blk= dev->internal_start_block;
  89                 !alloc_failed && blk <= dev->internal_end_block;
  90                 blk++) {
  91
  92                 YYIELD();
  93
  94                 bi = yaffs_get_block_info(dev, blk);
  95                 state = bi->block_state;
  96
  97                 deleted = 0;
  98
  99                 /* For each chunk in each block that needs scanning....*/
 100                 for (c = 0; !alloc_failed && c < dev->param.chunks_per_block &&
 101                      state == YAFFS_BLOCK_STATE_NEEDS_SCANNING; c++) {
 102                         /* Read the tags and decide what to do */
 103                         chunk = blk * dev->param.chunks_per_block + c;
 104
 105                         result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL,
 106                                                         &tags);
 107
 108                         /* Let's have a good look at this chunk... */
 109
 110                         if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED || tags.is_deleted) {
 111                                 /* YAFFS1 only...
 112                                  * A deleted chunk
 113                                  */
 114                                 deleted++;
 115                                 dev->n_free_chunks++;
 116                                 /*T((" %d %d deleted\n",blk,c)); */
 117                         } else if (!tags.chunk_used) {
 118                                 /* An unassigned chunk in the block
 119                                  * This means that either the block is empty or
 120                                  * this is the one being allocated from
 121                                  */
 122
 123                                 if (c == 0) {
 124                                         /* We're looking at the first chunk in the block so the block is unused */
 125                                         state = YAFFS_BLOCK_STATE_EMPTY;
 126                                         dev->n_erased_blocks++;
 127                                 } else {
 128                                         /* this is the block being allocated from */
 129                                         T(YAFFS_TRACE_SCAN,
 130                                           (TSTR
 131                                            (" Allocating from %d %d" TENDSTR),
 132                                            blk, c));
 133                                         state = YAFFS_BLOCK_STATE_ALLOCATING;
 134                                         dev->alloc_block = blk;
 135                                         dev->alloc_page = c;
 136                                         dev->alloc_block_finder = blk;
 137                                         /* Set block finder here to encourage the allocator to go forth from here. */
 138
 139                                 }
 140
 141                                 dev->n_free_chunks += (dev->param.chunks_per_block - c);
 142                         } else if (tags.chunk_id > 0) {
 143                                 /* chunk_id > 0 so it is a data chunk... */
 144                                 unsigned int endpos;
 145
 146                                 yaffs_set_chunk_bit(dev, blk, c);
 147                                 bi->pages_in_use++;
 148
 149                                 in = yaffs_find_or_create_by_number(dev,
 150                                                                       tags.
 151                                                                       obj_id,
 152                                                                       YAFFS_OBJECT_TYPE_FILE);
 153                                 /* PutChunkIntoFile checks for a clash (two data chunks with
 154                                  * the same chunk_id).
 155                                  */
 156
 157                                 if (!in)
 158                                         alloc_failed = 1;
 159
 160                                 if (in) {
 161                                         if (!yaffs_put_chunk_in_file(in, tags.chunk_id, chunk, 1))
 162                                                 alloc_failed = 1;
 163                                 }
 164
 165                                 endpos =
 166                                     (tags.chunk_id - 1) * dev->data_bytes_per_chunk +
 167                                     tags.n_bytes;
 168                                 if (in &&
 169                                     in->variant_type == YAFFS_OBJECT_TYPE_FILE
 170                                     && in->variant.file_variant.scanned_size <
 171                                     endpos) {
 172                                         in->variant.file_variant.
 173                                             scanned_size = endpos;
 174                                         if (!dev->param.use_header_file_size) {
 175                                                 in->variant.file_variant.
 176                                                     file_size =
 177                                                     in->variant.file_variant.
 178                                                     scanned_size;
 179                                         }
 180
 181                                 }
 182                                 /* T((" %d %d data %d %d\n",blk,c,tags.obj_id,tags.chunk_id));   */
 183                         } else {
 184                                 /* chunk_id == 0, so it is an ObjectHeader.
 185                                  * Thus, we read in the object header and make the object
 186                                  */
 187                                 yaffs_set_chunk_bit(dev, blk, c);
 188                                 bi->pages_in_use++;
 189
 190                                 result = yaffs_rd_chunk_tags_nand(dev, chunk,
 191                                                                 chunk_data,
 192                                                                 NULL);
 193
 194                                 oh = (struct yaffs_obj_hdr *) chunk_data;
 195
 196                                 in = yaffs_find_by_number(dev,
 197                                                               tags.obj_id);
 198                                 if (in && in->variant_type != oh->type) {
 199                                         /* This should not happen, but somehow
 200                                          * Wev'e ended up with an obj_id that has been reused but not yet
 201                                          * deleted, and worse still it has changed type. Delete the old object.
 202                                          */
 203
 204                                         yaffs_del_obj(in);
 205
 206                                         in = 0;
 207                                 }
 208
 209                                 in = yaffs_find_or_create_by_number(dev,
 210                                                                       tags.
 211                                                                       obj_id,
 212                                                                       oh->type);
 213
 214                                 if (!in)
 215                                         alloc_failed = 1;
 216
 217                                 if (in && oh->shadows_obj > 0) {
 218
 219                                         struct yaffs_shadow_fixer *fixer;
 220                                         fixer = YMALLOC(sizeof(struct yaffs_shadow_fixer));
 221                                         if (fixer) {
 222                                                 fixer->next = shadow_fixers;
 223                                                 shadow_fixers = fixer;
 224                                                 fixer->obj_id = tags.obj_id;
 225                                                 fixer->shadowed_id = oh->shadows_obj;
 226                                                 T(YAFFS_TRACE_SCAN,
 227                                                   (TSTR
 228                                                    (" Shadow fixer: %d shadows %d" TENDSTR),
 229                                                    fixer->obj_id, fixer->shadowed_id));
 230
 231                                         }
 232
 233                                 }
 234
 235                                 if (in && in->valid) {
 236                                         /* We have already filled this one. We have a duplicate and need to resolve it. */
 237
 238                                         unsigned existing_serial = in->serial;
 239                                         unsigned new_serial = tags.serial_number;
 240
 241                                         if (((existing_serial + 1) & 3) == new_serial) {
 242                                                 /* Use new one - destroy the exisiting one */
 243                                                 yaffs_chunk_del(dev,
 244                                                                   in->hdr_chunk,
 245                                                                   1, __LINE__);
 246                                                 in->valid = 0;
 247                                         } else {
 248                                                 /* Use existing - destroy this one. */
 249                                                 yaffs_chunk_del(dev, chunk, 1,
 250                                                                   __LINE__);
 251                                         }
 252                                 }
 253
 254                                 if (in && !in->valid &&
 255                                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
 256                                      tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND)) {
 257                                         /* We only load some info, don't fiddle with directory structure */
 258                                         in->valid = 1;
 259                                         in->variant_type = oh->type;
 260
 261                                         in->yst_mode = oh->yst_mode;
 262                                         yaffs_load_attribs(in, oh);
 263                                         in->hdr_chunk = chunk;
 264                                         in->serial = tags.serial_number;
 265
 266                                 } else if (in && !in->valid) {
 267                                         /* we need to load this info */
 268
 269                                         in->valid = 1;
 270                                         in->variant_type = oh->type;
 271
 272                                         in->yst_mode = oh->yst_mode;
 273                                         yaffs_load_attribs(in, oh);
 274                                         in->hdr_chunk = chunk;
 275                                         in->serial = tags.serial_number;
 276
 277                                         yaffs_set_obj_name_from_oh(in, oh);
 278                                         in->dirty = 0;
 279
 280                                         /* directory stuff...
 281                                          * hook up to parent
 282                                          */
 283
 284                                         parent =
 285                                             yaffs_find_or_create_by_number
 286                                             (dev, oh->parent_obj_id,
 287                                              YAFFS_OBJECT_TYPE_DIRECTORY);
 288                                         if (!parent)
 289                                                 alloc_failed = 1;
 290                                         if (parent && parent->variant_type ==
 291                                             YAFFS_OBJECT_TYPE_UNKNOWN) {
 292                                                 /* Set up as a directory */
 293                                                 parent->variant_type =
 294                                                         YAFFS_OBJECT_TYPE_DIRECTORY;
 295                                                 INIT_LIST_HEAD(&parent->variant.
 296                                                                 dir_variant.
 297                                                                 children);
 298                                         } else if (!parent || parent->variant_type !=
 299                                                    YAFFS_OBJECT_TYPE_DIRECTORY) {
 300                                                 /* Hoosterman, another problem....
 301                                                  * We're trying to use a non-directory as a directory
 302                                                  */
 303
 304                                                 T(YAFFS_TRACE_ERROR,
 305                                                   (TSTR
 306                                                    ("yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
 307                                                     TENDSTR)));
 308                                                 parent = dev->lost_n_found;
 309                                         }
 310
 311                                         yaffs_add_obj_to_dir(parent, in);
 312
 313                                         if (0 && (parent == dev->del_dir ||
 314                                                   parent == dev->unlinked_dir)) {
 315                                                 in->deleted = 1;        /* If it is unlinked at start up then it wants deleting */
 316                                                 dev->n_deleted_files++;
 317                                         }
 318                                         /* Note re hardlinks.
 319                                          * Since we might scan a hardlink before its equivalent object is scanned
 320                                          * we put them all in a list.
 321                                          * After scanning is complete, we should have all the objects, so we run through this
 322                                          * list and fix up all the chains.
 323                                          */
 324
 325                                         switch (in->variant_type) {
 326                                         case YAFFS_OBJECT_TYPE_UNKNOWN:
 327                                                 /* Todo got a problem */
 328                                                 break;
 329                                         case YAFFS_OBJECT_TYPE_FILE:
 330                                                 if (dev->param.use_header_file_size)
 331
 332                                                         in->variant.file_variant.
 333                                                             file_size =
 334                                                             oh->file_size;
 335
 336                                                 break;
 337                                         case YAFFS_OBJECT_TYPE_HARDLINK:
 338                                                 in->variant.hardlink_variant.
 339                                                         equiv_id =
 340                                                         oh->equiv_id;
 341                                                 in->hard_links.next =
 342                                                         (struct list_head *)
 343                                                         hard_list;
 344                                                 hard_list = in;
 345                                                 break;
 346                                         case YAFFS_OBJECT_TYPE_DIRECTORY:
 347                                                 /* Do nothing */
 348                                                 break;
 349                                         case YAFFS_OBJECT_TYPE_SPECIAL:
 350                                                 /* Do nothing */
 351                                                 break;
 352                                         case YAFFS_OBJECT_TYPE_SYMLINK:
 353                                                 in->variant.symlink_variant.alias =
 354                                                     yaffs_clone_str(oh->alias);
 355                                                 if (!in->variant.symlink_variant.alias)
 356                                                         alloc_failed = 1;
 357                                                 break;
 358                                         }
 359
 360                                 }
 361                         }
 362                 }
 363
 364                 if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
 365                         /* If we got this far while scanning, then the block is fully allocated.*/
 366                         state = YAFFS_BLOCK_STATE_FULL;
 367                 }
 368
 369                 if (state == YAFFS_BLOCK_STATE_ALLOCATING) {
 370                         /* If the block was partially allocated then treat it as fully allocated.*/
 371                         state = YAFFS_BLOCK_STATE_FULL;
 372                         dev->alloc_block = -1;
 373                 }
 374
 375                 bi->block_state = state;
 376
 377                 /* Now let's see if it was dirty */
 378                 if (bi->pages_in_use == 0 &&
 379                     !bi->has_shrink_hdr &&
 380                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
 381                         yaffs_block_became_dirty(dev, blk);
 382                 }
 383
 384         }
 385
 386
 387         /* Ok, we've done all the scanning.
 388          * Fix up the hard link chains.
 389          * We should now have scanned all the objects, now it's time to add these
 390          * hardlinks.
 391          */
 392
 393         yaffs_link_fixup(dev, hard_list);
 394
 395         /* Fix up any shadowed objects */
 396         {
 397                 struct yaffs_shadow_fixer *fixer;
 398                 struct yaffs_obj *obj;
 399
 400                 while (shadow_fixers) {
 401                         fixer = shadow_fixers;
 402                         shadow_fixers = fixer->next;
 403                         /* Complete the rename transaction by deleting the shadowed object
 404                          * then setting the object header to unshadowed.
 405                          */
 406                         obj = yaffs_find_by_number(dev, fixer->shadowed_id);
 407                         if (obj)
 408                                 yaffs_del_obj(obj);
 409
 410                         obj = yaffs_find_by_number(dev, fixer->obj_id);
 411
 412                         if (obj)
 413                                 yaffs_update_oh(obj, NULL, 1, 0, 0, NULL);
 414
 415                         YFREE(fixer);
 416                 }
 417         }
 418
 419         yaffs_release_temp_buffer(dev, chunk_data, __LINE__);
 420
 421         if (alloc_failed)
 422                 return YAFFS_FAIL;
 423
 424         T(YAFFS_TRACE_SCAN, (TSTR("yaffs1_scan ends" TENDSTR)));
 425
 426
 427         return YAFFS_OK;
 428 }
 429