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   1 /*
   2  *  linux/fs/affs/file.c
   3  *
   4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5  *
   6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7  *
   8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9  *
  10  *  (C) 1991  Linus Torvalds - minix filesystem
  11  *
  12  *  affs regular file handling primitives
  13  */
  14
  15 #include "affs.h"
  16
  17 #if PAGE_SIZE < 4096
  18 #error PAGE_SIZE must be at least 4096
  19 #endif
  20
  21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
  22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
  23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
  24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  25 static int affs_file_open(struct inode *inode, struct file *filp);
  26 static int affs_file_release(struct inode *inode, struct file *filp);
  27
  28 const struct file_operations affs_file_operations = {
  29         .llseek         = generic_file_llseek,
  30         .read           = do_sync_read,
  31         .aio_read       = generic_file_aio_read,
  32         .write          = do_sync_write,
  33         .aio_write      = generic_file_aio_write,
  34         .mmap           = generic_file_mmap,
  35         .open           = affs_file_open,
  36         .release        = affs_file_release,
  37         .fsync          = file_fsync,
  38         .splice_read    = generic_file_splice_read,
  39 };
  40
  41 const struct inode_operations affs_file_inode_operations = {
  42         .truncate       = affs_truncate,
  43         .setattr        = affs_notify_change,
  44 };
  45
  46 static int
  47 affs_file_open(struct inode *inode, struct file *filp)
  48 {
  49         if (atomic_read(&filp->f_count) != 1)
  50                 return 0;
  51         pr_debug("AFFS: open(%d)\n", AFFS_I(inode)->i_opencnt);
  52         AFFS_I(inode)->i_opencnt++;
  53         return 0;
  54 }
  55
  56 static int
  57 affs_file_release(struct inode *inode, struct file *filp)
  58 {
  59         if (atomic_read(&filp->f_count) != 0)
  60                 return 0;
  61         pr_debug("AFFS: release(%d)\n", AFFS_I(inode)->i_opencnt);
  62         AFFS_I(inode)->i_opencnt--;
  63         if (!AFFS_I(inode)->i_opencnt)
  64                 affs_free_prealloc(inode);
  65
  66         return 0;
  67 }
  68
  69 static int
  70 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  71 {
  72         struct super_block      *sb = inode->i_sb;
  73         struct buffer_head      *bh;
  74         u32 lc_max;
  75         int i, j, key;
  76
  77         if (!AFFS_I(inode)->i_lc) {
  78                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  79                 if (!ptr)
  80                         return -ENOMEM;
  81                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  82                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  83         }
  84
  85         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  86
  87         if (AFFS_I(inode)->i_extcnt > lc_max) {
  88                 u32 lc_shift, lc_mask, tmp, off;
  89
  90                 /* need to recalculate linear cache, start from old size */
  91                 lc_shift = AFFS_I(inode)->i_lc_shift;
  92                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  93                 for (; tmp; tmp >>= 1)
  94                         lc_shift++;
  95                 lc_mask = (1 << lc_shift) - 1;
  96
  97                 /* fix idx and old size to new shift */
  98                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  99                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 100
 101                 /* first shrink old cache to make more space */
 102                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 103                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 104                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 105
 106                 AFFS_I(inode)->i_lc_shift = lc_shift;
 107                 AFFS_I(inode)->i_lc_mask = lc_mask;
 108         }
 109
 110         /* fill cache to the needed index */
 111         i = AFFS_I(inode)->i_lc_size;
 112         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 113         for (; i <= lc_idx; i++) {
 114                 if (!i) {
 115                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 116                         continue;
 117                 }
 118                 key = AFFS_I(inode)->i_lc[i - 1];
 119                 j = AFFS_I(inode)->i_lc_mask + 1;
 120                 // unlock cache
 121                 for (; j > 0; j--) {
 122                         bh = affs_bread(sb, key);
 123                         if (!bh)
 124                                 goto err;
 125                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 126                         affs_brelse(bh);
 127                 }
 128                 // lock cache
 129                 AFFS_I(inode)->i_lc[i] = key;
 130         }
 131
 132         return 0;
 133
 134 err:
 135         // lock cache
 136         return -EIO;
 137 }
 138
 139 static struct buffer_head *
 140 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 141 {
 142         struct super_block *sb = inode->i_sb;
 143         struct buffer_head *new_bh;
 144         u32 blocknr, tmp;
 145
 146         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 147         if (!blocknr)
 148                 return ERR_PTR(-ENOSPC);
 149
 150         new_bh = affs_getzeroblk(sb, blocknr);
 151         if (!new_bh) {
 152                 affs_free_block(sb, blocknr);
 153                 return ERR_PTR(-EIO);
 154         }
 155
 156         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 157         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 158         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 159         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 160         affs_fix_checksum(sb, new_bh);
 161
 162         mark_buffer_dirty_inode(new_bh, inode);
 163
 164         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 165         if (tmp)
 166                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 167         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 168         affs_adjust_checksum(bh, blocknr - tmp);
 169         mark_buffer_dirty_inode(bh, inode);
 170
 171         AFFS_I(inode)->i_extcnt++;
 172         mark_inode_dirty(inode);
 173
 174         return new_bh;
 175 }
 176
 177 static inline struct buffer_head *
 178 affs_get_extblock(struct inode *inode, u32 ext)
 179 {
 180         /* inline the simplest case: same extended block as last time */
 181         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 182         if (ext == AFFS_I(inode)->i_ext_last)
 183                 atomic_inc(&bh->b_count);
 184         else
 185                 /* we have to do more (not inlined) */
 186                 bh = affs_get_extblock_slow(inode, ext);
 187
 188         return bh;
 189 }
 190
 191 static struct buffer_head *
 192 affs_get_extblock_slow(struct inode *inode, u32 ext)
 193 {
 194         struct super_block *sb = inode->i_sb;
 195         struct buffer_head *bh;
 196         u32 ext_key;
 197         u32 lc_idx, lc_off, ac_idx;
 198         u32 tmp, idx;
 199
 200         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 201                 /* read the next extended block from the current one */
 202                 bh = AFFS_I(inode)->i_ext_bh;
 203                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 204                 if (ext < AFFS_I(inode)->i_extcnt)
 205                         goto read_ext;
 206                 if (ext > AFFS_I(inode)->i_extcnt)
 207                         BUG();
 208                 bh = affs_alloc_extblock(inode, bh, ext);
 209                 if (IS_ERR(bh))
 210                         return bh;
 211                 goto store_ext;
 212         }
 213
 214         if (ext == 0) {
 215                 /* we seek back to the file header block */
 216                 ext_key = inode->i_ino;
 217                 goto read_ext;
 218         }
 219
 220         if (ext >= AFFS_I(inode)->i_extcnt) {
 221                 struct buffer_head *prev_bh;
 222
 223                 /* allocate a new extended block */
 224                 if (ext > AFFS_I(inode)->i_extcnt)
 225                         BUG();
 226
 227                 /* get previous extended block */
 228                 prev_bh = affs_get_extblock(inode, ext - 1);
 229                 if (IS_ERR(prev_bh))
 230                         return prev_bh;
 231                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 232                 affs_brelse(prev_bh);
 233                 if (IS_ERR(bh))
 234                         return bh;
 235                 goto store_ext;
 236         }
 237
 238 again:
 239         /* check if there is an extended cache and whether it's large enough */
 240         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 241         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 242
 243         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 244                 int err;
 245
 246                 err = affs_grow_extcache(inode, lc_idx);
 247                 if (err)
 248                         return ERR_PTR(err);
 249                 goto again;
 250         }
 251
 252         /* every n'th key we find in the linear cache */
 253         if (!lc_off) {
 254                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 255                 goto read_ext;
 256         }
 257
 258         /* maybe it's still in the associative cache */
 259         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 260         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 261                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 262                 goto read_ext;
 263         }
 264
 265         /* try to find one of the previous extended blocks */
 266         tmp = ext;
 267         idx = ac_idx;
 268         while (--tmp, --lc_off > 0) {
 269                 idx = (idx - 1) & AFFS_AC_MASK;
 270                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 271                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 272                         goto find_ext;
 273                 }
 274         }
 275
 276         /* fall back to the linear cache */
 277         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 278 find_ext:
 279         /* read all extended blocks until we find the one we need */
 280         //unlock cache
 281         do {
 282                 bh = affs_bread(sb, ext_key);
 283                 if (!bh)
 284                         goto err_bread;
 285                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 286                 affs_brelse(bh);
 287                 tmp++;
 288         } while (tmp < ext);
 289         //lock cache
 290
 291         /* store it in the associative cache */
 292         // recalculate ac_idx?
 293         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 294         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 295
 296 read_ext:
 297         /* finally read the right extended block */
 298         //unlock cache
 299         bh = affs_bread(sb, ext_key);
 300         if (!bh)
 301                 goto err_bread;
 302         //lock cache
 303
 304 store_ext:
 305         /* release old cached extended block and store the new one */
 306         affs_brelse(AFFS_I(inode)->i_ext_bh);
 307         AFFS_I(inode)->i_ext_last = ext;
 308         AFFS_I(inode)->i_ext_bh = bh;
 309         atomic_inc(&bh->b_count);
 310
 311         return bh;
 312
 313 err_bread:
 314         affs_brelse(bh);
 315         return ERR_PTR(-EIO);
 316 }
 317
 318 static int
 319 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 320 {
 321         struct super_block      *sb = inode->i_sb;
 322         struct buffer_head      *ext_bh;
 323         u32                      ext;
 324
 325         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 326
 327
 328         if (block > (sector_t)0x7fffffffUL)
 329                 BUG();
 330
 331         if (block >= AFFS_I(inode)->i_blkcnt) {
 332                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 333                         goto err_big;
 334         } else
 335                 create = 0;
 336
 337         //lock cache
 338         affs_lock_ext(inode);
 339
 340         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 341         block -= ext * AFFS_SB(sb)->s_hashsize;
 342         ext_bh = affs_get_extblock(inode, ext);
 343         if (IS_ERR(ext_bh))
 344                 goto err_ext;
 345         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 346
 347         if (create) {
 348                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 349                 if (!blocknr)
 350                         goto err_alloc;
 351                 set_buffer_new(bh_result);
 352                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 353                 AFFS_I(inode)->i_blkcnt++;
 354
 355                 /* store new block */
 356                 if (bh_result->b_blocknr)
 357                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
 358                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 359                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 360                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 361                 bh_result->b_blocknr = blocknr;
 362
 363                 if (!block) {
 364                         /* insert first block into header block */
 365                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 366                         if (tmp)
 367                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 368                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 369                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 370                 }
 371         }
 372
 373         affs_brelse(ext_bh);
 374         //unlock cache
 375         affs_unlock_ext(inode);
 376         return 0;
 377
 378 err_big:
 379         affs_error(inode->i_sb,"get_block","strange block request %d", block);
 380         return -EIO;
 381 err_ext:
 382         // unlock cache
 383         affs_unlock_ext(inode);
 384         return PTR_ERR(ext_bh);
 385 err_alloc:
 386         brelse(ext_bh);
 387         clear_buffer_mapped(bh_result);
 388         bh_result->b_bdev = NULL;
 389         // unlock cache
 390         affs_unlock_ext(inode);
 391         return -ENOSPC;
 392 }
 393
 394 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 395 {
 396         return block_write_full_page(page, affs_get_block, wbc);
 397 }
 398 static int affs_readpage(struct file *file, struct page *page)
 399 {
 400         return block_read_full_page(page, affs_get_block);
 401 }
 402 static int affs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
 403 {
 404         return cont_prepare_write(page, from, to, affs_get_block,
 405                 &AFFS_I(page->mapping->host)->mmu_private);
 406 }
 407 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 408 {
 409         return generic_block_bmap(mapping,block,affs_get_block);
 410 }
 411 const struct address_space_operations affs_aops = {
 412         .readpage = affs_readpage,
 413         .writepage = affs_writepage,
 414         .sync_page = block_sync_page,
 415         .prepare_write = affs_prepare_write,
 416         .commit_write = generic_commit_write,
 417         .bmap = _affs_bmap
 418 };
 419
 420 static inline struct buffer_head *
 421 affs_bread_ino(struct inode *inode, int block, int create)
 422 {
 423         struct buffer_head *bh, tmp_bh;
 424         int err;
 425
 426         tmp_bh.b_state = 0;
 427         err = affs_get_block(inode, block, &tmp_bh, create);
 428         if (!err) {
 429                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 430                 if (bh) {
 431                         bh->b_state |= tmp_bh.b_state;
 432                         return bh;
 433                 }
 434                 err = -EIO;
 435         }
 436         return ERR_PTR(err);
 437 }
 438
 439 static inline struct buffer_head *
 440 affs_getzeroblk_ino(struct inode *inode, int block)
 441 {
 442         struct buffer_head *bh, tmp_bh;
 443         int err;
 444
 445         tmp_bh.b_state = 0;
 446         err = affs_get_block(inode, block, &tmp_bh, 1);
 447         if (!err) {
 448                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 449                 if (bh) {
 450                         bh->b_state |= tmp_bh.b_state;
 451                         return bh;
 452                 }
 453                 err = -EIO;
 454         }
 455         return ERR_PTR(err);
 456 }
 457
 458 static inline struct buffer_head *
 459 affs_getemptyblk_ino(struct inode *inode, int block)
 460 {
 461         struct buffer_head *bh, tmp_bh;
 462         int err;
 463
 464         tmp_bh.b_state = 0;
 465         err = affs_get_block(inode, block, &tmp_bh, 1);
 466         if (!err) {
 467                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 468                 if (bh) {
 469                         bh->b_state |= tmp_bh.b_state;
 470                         return bh;
 471                 }
 472                 err = -EIO;
 473         }
 474         return ERR_PTR(err);
 475 }
 476
 477 static int
 478 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 479 {
 480         struct inode *inode = page->mapping->host;
 481         struct super_block *sb = inode->i_sb;
 482         struct buffer_head *bh;
 483         char *data;
 484         u32 bidx, boff, bsize;
 485         u32 tmp;
 486
 487         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 488         if (from > to || to > PAGE_CACHE_SIZE)
 489                 BUG();
 490         kmap(page);
 491         data = page_address(page);
 492         bsize = AFFS_SB(sb)->s_data_blksize;
 493         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 494         bidx = tmp / bsize;
 495         boff = tmp % bsize;
 496
 497         while (from < to) {
 498                 bh = affs_bread_ino(inode, bidx, 0);
 499                 if (IS_ERR(bh))
 500                         return PTR_ERR(bh);
 501                 tmp = min(bsize - boff, to - from);
 502                 if (from + tmp > to || tmp > bsize)
 503                         BUG();
 504                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 505                 affs_brelse(bh);
 506                 bidx++;
 507                 from += tmp;
 508                 boff = 0;
 509         }
 510         flush_dcache_page(page);
 511         kunmap(page);
 512         return 0;
 513 }
 514
 515 static int
 516 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 517 {
 518         struct super_block *sb = inode->i_sb;
 519         struct buffer_head *bh, *prev_bh;
 520         u32 bidx, boff;
 521         u32 size, bsize;
 522         u32 tmp;
 523
 524         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 525         bsize = AFFS_SB(sb)->s_data_blksize;
 526         bh = NULL;
 527         size = AFFS_I(inode)->mmu_private;
 528         bidx = size / bsize;
 529         boff = size % bsize;
 530         if (boff) {
 531                 bh = affs_bread_ino(inode, bidx, 0);
 532                 if (IS_ERR(bh))
 533                         return PTR_ERR(bh);
 534                 tmp = min(bsize - boff, newsize - size);
 535                 if (boff + tmp > bsize || tmp > bsize)
 536                         BUG();
 537                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 538                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
 539                 affs_fix_checksum(sb, bh);
 540                 mark_buffer_dirty_inode(bh, inode);
 541                 size += tmp;
 542                 bidx++;
 543         } else if (bidx) {
 544                 bh = affs_bread_ino(inode, bidx - 1, 0);
 545                 if (IS_ERR(bh))
 546                         return PTR_ERR(bh);
 547         }
 548
 549         while (size < newsize) {
 550                 prev_bh = bh;
 551                 bh = affs_getzeroblk_ino(inode, bidx);
 552                 if (IS_ERR(bh))
 553                         goto out;
 554                 tmp = min(bsize, newsize - size);
 555                 if (tmp > bsize)
 556                         BUG();
 557                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 558                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 559                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 560                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 561                 affs_fix_checksum(sb, bh);
 562                 bh->b_state &= ~(1UL << BH_New);
 563                 mark_buffer_dirty_inode(bh, inode);
 564                 if (prev_bh) {
 565                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 566                         if (tmp)
 567                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 568                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 569                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 570                         mark_buffer_dirty_inode(prev_bh, inode);
 571                         affs_brelse(prev_bh);
 572                 }
 573                 size += bsize;
 574                 bidx++;
 575         }
 576         affs_brelse(bh);
 577         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 578         return 0;
 579
 580 out:
 581         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 582         return PTR_ERR(bh);
 583 }
 584
 585 static int
 586 affs_readpage_ofs(struct file *file, struct page *page)
 587 {
 588         struct inode *inode = page->mapping->host;
 589         u32 to;
 590         int err;
 591
 592         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 593         to = PAGE_CACHE_SIZE;
 594         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 595                 to = inode->i_size & ~PAGE_CACHE_MASK;
 596                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 597         }
 598
 599         err = affs_do_readpage_ofs(file, page, 0, to);
 600         if (!err)
 601                 SetPageUptodate(page);
 602         unlock_page(page);
 603         return err;
 604 }
 605
 606 static int affs_prepare_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 607 {
 608         struct inode *inode = page->mapping->host;
 609         u32 size, offset;
 610         u32 tmp;
 611         int err = 0;
 612
 613         pr_debug("AFFS: prepare_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 614         offset = page->index << PAGE_CACHE_SHIFT;
 615         if (offset + from > AFFS_I(inode)->mmu_private) {
 616                 err = affs_extent_file_ofs(inode, offset + from);
 617                 if (err)
 618                         return err;
 619         }
 620         size = inode->i_size;
 621
 622         if (PageUptodate(page))
 623                 return 0;
 624
 625         if (from) {
 626                 err = affs_do_readpage_ofs(file, page, 0, from);
 627                 if (err)
 628                         return err;
 629         }
 630         if (to < PAGE_CACHE_SIZE) {
 631                 zero_user_page(page, to, PAGE_CACHE_SIZE - to, KM_USER0);
 632                 if (size > offset + to) {
 633                         if (size < offset + PAGE_CACHE_SIZE)
 634                                 tmp = size & ~PAGE_CACHE_MASK;
 635                         else
 636                                 tmp = PAGE_CACHE_SIZE;
 637                         err = affs_do_readpage_ofs(file, page, to, tmp);
 638                 }
 639         }
 640         return err;
 641 }
 642
 643 static int affs_commit_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 644 {
 645         struct inode *inode = page->mapping->host;
 646         struct super_block *sb = inode->i_sb;
 647         struct buffer_head *bh, *prev_bh;
 648         char *data;
 649         u32 bidx, boff, bsize;
 650         u32 tmp;
 651         int written;
 652
 653         pr_debug("AFFS: commit_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 654         bsize = AFFS_SB(sb)->s_data_blksize;
 655         data = page_address(page);
 656
 657         bh = NULL;
 658         written = 0;
 659         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 660         bidx = tmp / bsize;
 661         boff = tmp % bsize;
 662         if (boff) {
 663                 bh = affs_bread_ino(inode, bidx, 0);
 664                 if (IS_ERR(bh))
 665                         return PTR_ERR(bh);
 666                 tmp = min(bsize - boff, to - from);
 667                 if (boff + tmp > bsize || tmp > bsize)
 668                         BUG();
 669                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 670                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
 671                 affs_fix_checksum(sb, bh);
 672                 mark_buffer_dirty_inode(bh, inode);
 673                 written += tmp;
 674                 from += tmp;
 675                 bidx++;
 676         } else if (bidx) {
 677                 bh = affs_bread_ino(inode, bidx - 1, 0);
 678                 if (IS_ERR(bh))
 679                         return PTR_ERR(bh);
 680         }
 681         while (from + bsize <= to) {
 682                 prev_bh = bh;
 683                 bh = affs_getemptyblk_ino(inode, bidx);
 684                 if (IS_ERR(bh))
 685                         goto out;
 686                 memcpy(AFFS_DATA(bh), data + from, bsize);
 687                 if (buffer_new(bh)) {
 688                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 689                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 690                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 691                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 692                         AFFS_DATA_HEAD(bh)->next = 0;
 693                         bh->b_state &= ~(1UL << BH_New);
 694                         if (prev_bh) {
 695                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 696                                 if (tmp)
 697                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 698                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 699                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 700                                 mark_buffer_dirty_inode(prev_bh, inode);
 701                         }
 702                 }
 703                 affs_brelse(prev_bh);
 704                 affs_fix_checksum(sb, bh);
 705                 mark_buffer_dirty_inode(bh, inode);
 706                 written += bsize;
 707                 from += bsize;
 708                 bidx++;
 709         }
 710         if (from < to) {
 711                 prev_bh = bh;
 712                 bh = affs_bread_ino(inode, bidx, 1);
 713                 if (IS_ERR(bh))
 714                         goto out;
 715                 tmp = min(bsize, to - from);
 716                 if (tmp > bsize)
 717                         BUG();
 718                 memcpy(AFFS_DATA(bh), data + from, tmp);
 719                 if (buffer_new(bh)) {
 720                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 721                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 722                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 723                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 724                         AFFS_DATA_HEAD(bh)->next = 0;
 725                         bh->b_state &= ~(1UL << BH_New);
 726                         if (prev_bh) {
 727                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 728                                 if (tmp)
 729                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 730                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 731                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 732                                 mark_buffer_dirty_inode(prev_bh, inode);
 733                         }
 734                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 735                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 736                 affs_brelse(prev_bh);
 737                 affs_fix_checksum(sb, bh);
 738                 mark_buffer_dirty_inode(bh, inode);
 739                 written += tmp;
 740                 from += tmp;
 741                 bidx++;
 742         }
 743         SetPageUptodate(page);
 744
 745 done:
 746         affs_brelse(bh);
 747         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 748         if (tmp > inode->i_size)
 749                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 750
 751         return written;
 752
 753 out:
 754         bh = prev_bh;
 755         if (!written)
 756                 written = PTR_ERR(bh);
 757         goto done;
 758 }
 759
 760 const struct address_space_operations affs_aops_ofs = {
 761         .readpage = affs_readpage_ofs,
 762         //.writepage = affs_writepage_ofs,
 763         //.sync_page = affs_sync_page_ofs,
 764         .prepare_write = affs_prepare_write_ofs,
 765         .commit_write = affs_commit_write_ofs
 766 };
 767
 768 /* Free any preallocated blocks. */
 769
 770 void
 771 affs_free_prealloc(struct inode *inode)
 772 {
 773         struct super_block *sb = inode->i_sb;
 774
 775         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 776
 777         while (AFFS_I(inode)->i_pa_cnt) {
 778                 AFFS_I(inode)->i_pa_cnt--;
 779                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 780         }
 781 }
 782
 783 /* Truncate (or enlarge) a file to the requested size. */
 784
 785 void
 786 affs_truncate(struct inode *inode)
 787 {
 788         struct super_block *sb = inode->i_sb;
 789         u32 ext, ext_key;
 790         u32 last_blk, blkcnt, blk;
 791         u32 size;
 792         struct buffer_head *ext_bh;
 793         int i;
 794
 795         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 796                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 797
 798         last_blk = 0;
 799         ext = 0;
 800         if (inode->i_size) {
 801                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 802                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 803         }
 804
 805         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 806                 struct address_space *mapping = inode->i_mapping;
 807                 struct page *page;
 808                 u32 size = inode->i_size - 1;
 809                 int res;
 810
 811                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
 812                 if (!page)
 813                         return;
 814                 size = (size & (PAGE_CACHE_SIZE - 1)) + 1;
 815                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
 816                 if (!res)
 817                         res = mapping->a_ops->commit_write(NULL, page, size, size);
 818                 unlock_page(page);
 819                 page_cache_release(page);
 820                 mark_inode_dirty(inode);
 821                 return;
 822         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 823                 return;
 824
 825         // lock cache
 826         ext_bh = affs_get_extblock(inode, ext);
 827         if (IS_ERR(ext_bh)) {
 828                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 829                              ext, PTR_ERR(ext_bh));
 830                 return;
 831         }
 832         if (AFFS_I(inode)->i_lc) {
 833                 /* clear linear cache */
 834                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 835                 if (AFFS_I(inode)->i_lc_size > i) {
 836                         AFFS_I(inode)->i_lc_size = i;
 837                         for (; i < AFFS_LC_SIZE; i++)
 838                                 AFFS_I(inode)->i_lc[i] = 0;
 839                 }
 840                 /* clear associative cache */
 841                 for (i = 0; i < AFFS_AC_SIZE; i++)
 842                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 843                                 AFFS_I(inode)->i_ac[i].ext = 0;
 844         }
 845         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 846
 847         blkcnt = AFFS_I(inode)->i_blkcnt;
 848         i = 0;
 849         blk = last_blk;
 850         if (inode->i_size) {
 851                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 852                 blk++;
 853         } else
 854                 AFFS_HEAD(ext_bh)->first_data = 0;
 855         size = AFFS_SB(sb)->s_hashsize;
 856         if (size > blkcnt - blk + i)
 857                 size = blkcnt - blk + i;
 858         for (; i < size; i++, blk++) {
 859                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 860                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 861         }
 862         AFFS_TAIL(sb, ext_bh)->extension = 0;
 863         affs_fix_checksum(sb, ext_bh);
 864         mark_buffer_dirty_inode(ext_bh, inode);
 865         affs_brelse(ext_bh);
 866
 867         if (inode->i_size) {
 868                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 869                 AFFS_I(inode)->i_extcnt = ext + 1;
 870                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 871                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 872                         u32 tmp;
 873                         if (IS_ERR(ext_bh)) {
 874                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 875                                              ext, PTR_ERR(ext_bh));
 876                                 return;
 877                         }
 878                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 879                         AFFS_DATA_HEAD(bh)->next = 0;
 880                         affs_adjust_checksum(bh, -tmp);
 881                         affs_brelse(bh);
 882                 }
 883         } else {
 884                 AFFS_I(inode)->i_blkcnt = 0;
 885                 AFFS_I(inode)->i_extcnt = 1;
 886         }
 887         AFFS_I(inode)->mmu_private = inode->i_size;
 888         // unlock cache
 889
 890         while (ext_key) {
 891                 ext_bh = affs_bread(sb, ext_key);
 892                 size = AFFS_SB(sb)->s_hashsize;
 893                 if (size > blkcnt - blk)
 894                         size = blkcnt - blk;
 895                 for (i = 0; i < size; i++, blk++)
 896                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 897                 affs_free_block(sb, ext_key);
 898                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 899                 affs_brelse(ext_bh);
 900         }
 901         affs_free_prealloc(inode);
 902 }