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