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         u8 *chunk_data;
  44
  45         yaffs_trace(YAFFS_TRACE_SCAN,
  46                 "yaffs1_scan starts  intstartblk %d intendblk %d...",
  47                 dev->internal_start_block, dev->internal_end_block);
  48
  49         chunk_data = yaffs_get_temp_buffer(dev, __LINE__);
  50
  51         dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
  52
  53         /* Scan all the blocks to determine their state */
  54         bi = dev->block_info;
  55         for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
  56              blk++) {
  57                 yaffs_clear_chunk_bits(dev, blk);
  58                 bi->pages_in_use = 0;
  59                 bi->soft_del_pages = 0;
  60
  61                 yaffs_query_init_block_state(dev, blk, &state, &seq_number);
  62
  63                 bi->block_state = state;
  64                 bi->seq_number = seq_number;
  65
  66                 if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
  67                         bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
  68
  69                 yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
  70                         "Block scanning block %d state %d seq %d",
  71                         blk, state, seq_number);
  72
  73                 if (state == YAFFS_BLOCK_STATE_DEAD) {
  74                         yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
  75                                 "block %d is bad", blk);
  76                 } else if (state == YAFFS_BLOCK_STATE_EMPTY) {
  77                         yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
  78                         dev->n_erased_blocks++;
  79                         dev->n_free_chunks += dev->param.chunks_per_block;
  80                 }
  81                 bi++;
  82         }
  83
  84         /* For each block.... */
  85         for (blk = dev->internal_start_block;
  86              !alloc_failed && blk <= dev->internal_end_block; blk++) {
  87
  88                 cond_resched();
  89
  90                 bi = yaffs_get_block_info(dev, blk);
  91                 state = bi->block_state;
  92
  93                 deleted = 0;
  94
  95                 /* For each chunk in each block that needs scanning.... */
  96                 for (c = 0; !alloc_failed && c < dev->param.chunks_per_block &&
  97                      state == YAFFS_BLOCK_STATE_NEEDS_SCANNING; c++) {
  98                         /* Read the tags and decide what to do */
  99                         chunk = blk * dev->param.chunks_per_block + c;
 100
 101                         result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL,
 102                                                           &tags);
 103
 104                         /* Let's have a good look at this chunk... */
 105
 106                         if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED
 107                             || tags.is_deleted) {
 108                                 /* YAFFS1 only...
 109                                  * A deleted chunk
 110                                  */
 111                                 deleted++;
 112                                 dev->n_free_chunks++;
 113                         } else if (!tags.chunk_used) {
 114                                 /* An unassigned chunk in the block
 115                                  * This means that either the block is empty or
 116                                  * this is the one being allocated from
 117                                  */
 118
 119                                 if (c == 0) {
 120                                         /* We're looking at the first chunk in the block so the block is unused */
 121                                         state = YAFFS_BLOCK_STATE_EMPTY;
 122                                         dev->n_erased_blocks++;
 123                                 } else {
 124                                         /* this is the block being allocated from */
 125                                         yaffs_trace(YAFFS_TRACE_SCAN,
 126                                                 " Allocating from %d %d",
 127                                                 blk, c);
 128                                         state = YAFFS_BLOCK_STATE_ALLOCATING;
 129                                         dev->alloc_block = blk;
 130                                         dev->alloc_page = c;
 131                                         dev->alloc_block_finder = blk;
 132                                         /* Set block finder here to encourage the allocator to go forth from here. */
 133
 134                                 }
 135
 136                                 dev->n_free_chunks +=
 137                                     (dev->param.chunks_per_block - c);
 138                         } else if (tags.chunk_id > 0) {
 139                                 /* chunk_id > 0 so it is a data chunk... */
 140                                 unsigned int endpos;
 141
 142                                 yaffs_set_chunk_bit(dev, blk, c);
 143                                 bi->pages_in_use++;
 144
 145                                 in = yaffs_find_or_create_by_number(dev,
 146                                                                     tags.obj_id,
 147                                                                     YAFFS_OBJECT_TYPE_FILE);
 148                                 /* PutChunkIntoFile checks for a clash (two data chunks with
 149                                  * the same chunk_id).
 150                                  */
 151
 152                                 if (!in)
 153                                         alloc_failed = 1;
 154
 155                                 if (in) {
 156                                         if (!yaffs_put_chunk_in_file
 157                                             (in, tags.chunk_id, chunk, 1))
 158                                                 alloc_failed = 1;
 159                                 }
 160
 161                                 endpos =
 162                                     (tags.chunk_id -
 163                                      1) * dev->data_bytes_per_chunk +
 164                                     tags.n_bytes;
 165                                 if (in
 166                                     && in->variant_type ==
 167                                     YAFFS_OBJECT_TYPE_FILE
 168                                     && in->variant.file_variant.scanned_size <
 169                                     endpos) {
 170                                         in->variant.file_variant.scanned_size =
 171                                             endpos;
 172                                         if (!dev->param.use_header_file_size) {
 173                                                 in->variant.
 174                                                     file_variant.file_size =
 175                                                     in->variant.
 176                                                     file_variant.scanned_size;
 177                                         }
 178
 179                                 }
 180                         } else {
 181                                 /* chunk_id == 0, so it is an ObjectHeader.
 182                                  * Thus, we read in the object header and make the object
 183                                  */
 184                                 yaffs_set_chunk_bit(dev, blk, c);
 185                                 bi->pages_in_use++;
 186
 187                                 result = yaffs_rd_chunk_tags_nand(dev, chunk,
 188                                                                   chunk_data,
 189                                                                   NULL);
 190
 191                                 oh = (struct yaffs_obj_hdr *)chunk_data;
 192
 193                                 in = yaffs_find_by_number(dev, tags.obj_id);
 194                                 if (in && in->variant_type != oh->type) {
 195                                         /* This should not happen, but somehow
 196                                          * Wev'e ended up with an obj_id that has been reused but not yet
 197                                          * deleted, and worse still it has changed type. Delete the old object.
 198                                          */
 199
 200                                         yaffs_del_obj(in);
 201
 202                                         in = 0;
 203                                 }
 204
 205                                 in = yaffs_find_or_create_by_number(dev,
 206                                                                     tags.obj_id,
 207                                                                     oh->type);
 208
 209                                 if (!in)
 210                                         alloc_failed = 1;
 211
 212                                 if (in && oh->shadows_obj > 0) {
 213
 214                                         struct yaffs_shadow_fixer *fixer;
 215                                         fixer =
 216                                                 kmalloc(sizeof
 217                                                 (struct yaffs_shadow_fixer),
 218                                                 GFP_NOFS);
 219                                         if (fixer) {
 220                                                 fixer->next = shadow_fixers;
 221                                                 shadow_fixers = fixer;
 222                                                 fixer->obj_id = tags.obj_id;
 223                                                 fixer->shadowed_id =
 224                                                     oh->shadows_obj;
 225                                                 yaffs_trace(YAFFS_TRACE_SCAN,
 226                                                         " Shadow fixer: %d shadows %d",
 227                                                         fixer->obj_id,
 228                                                         fixer->shadowed_id);
 229
 230                                         }
 231
 232                                 }
 233
 234                                 if (in && in->valid) {
 235                                         /* We have already filled this one. We have a duplicate and need to resolve it. */
 236
 237                                         unsigned existing_serial = in->serial;
 238                                         unsigned new_serial =
 239                                             tags.serial_number;
 240
 241                                         if (((existing_serial + 1) & 3) ==
 242                                             new_serial) {
 243                                                 /* Use new one - destroy the exisiting one */
 244                                                 yaffs_chunk_del(dev,
 245                                                                 in->hdr_chunk,
 246                                                                 1, __LINE__);
 247                                                 in->valid = 0;
 248                                         } else {
 249                                                 /* Use existing - destroy this one. */
 250                                                 yaffs_chunk_del(dev, chunk, 1,
 251                                                                 __LINE__);
 252                                         }
 253                                 }
 254
 255                                 if (in && !in->valid &&
 256                                     (tags.obj_id == YAFFS_OBJECTID_ROOT ||
 257                                      tags.obj_id ==
 258                                      YAFFS_OBJECTID_LOSTNFOUND)) {
 259                                         /* We only load some info, don't fiddle with directory structure */
 260                                         in->valid = 1;
 261                                         in->variant_type = oh->type;
 262
 263                                         in->yst_mode = oh->yst_mode;
 264                                         yaffs_load_attribs(in, oh);
 265                                         in->hdr_chunk = chunk;
 266                                         in->serial = tags.serial_number;
 267
 268                                 } else if (in && !in->valid) {
 269                                         /* we need to load this info */
 270
 271                                         in->valid = 1;
 272                                         in->variant_type = oh->type;
 273
 274                                         in->yst_mode = oh->yst_mode;
 275                                         yaffs_load_attribs(in, oh);
 276                                         in->hdr_chunk = chunk;
 277                                         in->serial = tags.serial_number;
 278
 279                                         yaffs_set_obj_name_from_oh(in, oh);
 280                                         in->dirty = 0;
 281
 282                                         /* directory stuff...
 283                                          * hook up to parent
 284                                          */
 285
 286                                         parent =
 287                                             yaffs_find_or_create_by_number
 288                                             (dev, oh->parent_obj_id,
 289                                              YAFFS_OBJECT_TYPE_DIRECTORY);
 290                                         if (!parent)
 291                                                 alloc_failed = 1;
 292                                         if (parent && parent->variant_type ==
 293                                             YAFFS_OBJECT_TYPE_UNKNOWN) {
 294                                                 /* Set up as a directory */
 295                                                 parent->variant_type =
 296                                                     YAFFS_OBJECT_TYPE_DIRECTORY;
 297                                                 INIT_LIST_HEAD(&parent->
 298                                                                variant.dir_variant.children);
 299                                         } else if (!parent
 300                                                    || parent->variant_type !=
 301                                                    YAFFS_OBJECT_TYPE_DIRECTORY) {
 302                                                 /* Hoosterman, another problem....
 303                                                  * We're trying to use a non-directory as a directory
 304                                                  */
 305
 306                                                 yaffs_trace(YAFFS_TRACE_ERROR,
 307                                                         "yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
 308                                                         );
 309                                                 parent = dev->lost_n_found;
 310                                         }
 311
 312                                         yaffs_add_obj_to_dir(parent, in);
 313
 314                                         if (0 && (parent == dev->del_dir ||
 315                                                   parent ==
 316                                                   dev->unlinked_dir)) {
 317                                                 in->deleted = 1;        /* If it is unlinked at start up then it wants deleting */
 318                                                 dev->n_deleted_files++;
 319                                         }
 320                                         /* Note re hardlinks.
 321                                          * Since we might scan a hardlink before its equivalent object is scanned
 322                                          * we put them all in a list.
 323                                          * After scanning is complete, we should have all the objects, so we run through this
 324                                          * list and fix up all the chains.
 325                                          */
 326
 327                                         switch (in->variant_type) {
 328                                         case YAFFS_OBJECT_TYPE_UNKNOWN:
 329                                                 /* Todo got a problem */
 330                                                 break;
 331                                         case YAFFS_OBJECT_TYPE_FILE:
 332                                                 if (dev->param.
 333                                                     use_header_file_size)
 334
 335                                                         in->variant.
 336                                                             file_variant.file_size
 337                                                             = oh->file_size;
 338
 339                                                 break;
 340                                         case YAFFS_OBJECT_TYPE_HARDLINK:
 341                                                 in->variant.
 342                                                     hardlink_variant.equiv_id =
 343                                                     oh->equiv_id;
 344                                                 in->hard_links.next =
 345                                                     (struct list_head *)
 346                                                     hard_list;
 347                                                 hard_list = in;
 348                                                 break;
 349                                         case YAFFS_OBJECT_TYPE_DIRECTORY:
 350                                                 /* Do nothing */
 351                                                 break;
 352                                         case YAFFS_OBJECT_TYPE_SPECIAL:
 353                                                 /* Do nothing */
 354                                                 break;
 355                                         case YAFFS_OBJECT_TYPE_SYMLINK:
 356                                                 in->variant.symlink_variant.
 357                                                     alias =
 358                                                     yaffs_clone_str(oh->alias);
 359                                                 if (!in->variant.
 360                                                     symlink_variant.alias)
 361                                                         alloc_failed = 1;
 362                                                 break;
 363                                         }
 364
 365                                 }
 366                         }
 367                 }
 368
 369                 if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
 370                         /* If we got this far while scanning, then the block is fully allocated. */
 371                         state = YAFFS_BLOCK_STATE_FULL;
 372                 }
 373
 374                 if (state == YAFFS_BLOCK_STATE_ALLOCATING) {
 375                         /* If the block was partially allocated then treat it as fully allocated. */
 376                         state = YAFFS_BLOCK_STATE_FULL;
 377                         dev->alloc_block = -1;
 378                 }
 379
 380                 bi->block_state = state;
 381
 382                 /* Now let's see if it was dirty */
 383                 if (bi->pages_in_use == 0 &&
 384                     !bi->has_shrink_hdr &&
 385                     bi->block_state == YAFFS_BLOCK_STATE_FULL) {
 386                         yaffs_block_became_dirty(dev, blk);
 387                 }
 388
 389         }
 390
 391         /* Ok, we've done all the scanning.
 392          * Fix up the hard link chains.
 393          * We should now have scanned all the objects, now it's time to add these
 394          * hardlinks.
 395          */
 396
 397         yaffs_link_fixup(dev, hard_list);
 398
 399         /* Fix up any shadowed objects */
 400         {
 401                 struct yaffs_shadow_fixer *fixer;
 402                 struct yaffs_obj *obj;
 403
 404                 while (shadow_fixers) {
 405                         fixer = shadow_fixers;
 406                         shadow_fixers = fixer->next;
 407                         /* Complete the rename transaction by deleting the shadowed object
 408                          * then setting the object header to unshadowed.
 409                          */
 410                         obj = yaffs_find_by_number(dev, fixer->shadowed_id);
 411                         if (obj)
 412                                 yaffs_del_obj(obj);
 413
 414                         obj = yaffs_find_by_number(dev, fixer->obj_id);
 415
 416                         if (obj)
 417                                 yaffs_update_oh(obj, NULL, 1, 0, 0, NULL);
 418
 419                         kfree(fixer);
 420                 }
 421         }
 422
 423         yaffs_release_temp_buffer(dev, chunk_data, __LINE__);
 424
 425         if (alloc_failed)
 426                 return YAFFS_FAIL;
 427
 428         yaffs_trace(YAFFS_TRACE_SCAN, "yaffs1_scan ends");
 429
 430         return YAFFS_OK;
 431 }