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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 ssize_t affs_file_write(struct file *filp, const char __user *buf, size_t count, loff_t *ppos);
  26 static int affs_file_open(struct inode *inode, struct file *filp);
  27 static int affs_file_release(struct inode *inode, struct file *filp);
  28
  29 struct file_operations affs_file_operations = {
  30         .llseek         = generic_file_llseek,
  31         .read           = generic_file_read,
  32         .write          = affs_file_write,
  33         .mmap           = generic_file_mmap,
  34         .open           = affs_file_open,
  35         .release        = affs_file_release,
  36         .fsync          = file_fsync,
  37         .sendfile       = generic_file_sendfile,
  38 };
  39
  40 struct inode_operations affs_file_inode_operations = {
  41         .truncate       = affs_truncate,
  42         .setattr        = affs_notify_change,
  43 };
  44
  45 static int
  46 affs_file_open(struct inode *inode, struct file *filp)
  47 {
  48         if (atomic_read(&filp->f_count) != 1)
  49                 return 0;
  50         pr_debug("AFFS: open(%d)\n", AFFS_I(inode)->i_opencnt);
  51         AFFS_I(inode)->i_opencnt++;
  52         return 0;
  53 }
  54
  55 static int
  56 affs_file_release(struct inode *inode, struct file *filp)
  57 {
  58         if (atomic_read(&filp->f_count) != 0)
  59                 return 0;
  60         pr_debug("AFFS: release(%d)\n", AFFS_I(inode)->i_opencnt);
  61         AFFS_I(inode)->i_opencnt--;
  62         if (!AFFS_I(inode)->i_opencnt)
  63                 affs_free_prealloc(inode);
  64
  65         return 0;
  66 }
  67
  68 static int
  69 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  70 {
  71         struct super_block      *sb = inode->i_sb;
  72         struct buffer_head      *bh;
  73         u32 lc_max;
  74         int i, j, key;
  75
  76         if (!AFFS_I(inode)->i_lc) {
  77                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  78                 if (!ptr)
  79                         return -ENOMEM;
  80                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  81                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  82         }
  83
  84         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  85
  86         if (AFFS_I(inode)->i_extcnt > lc_max) {
  87                 u32 lc_shift, lc_mask, tmp, off;
  88
  89                 /* need to recalculate linear cache, start from old size */
  90                 lc_shift = AFFS_I(inode)->i_lc_shift;
  91                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  92                 for (; tmp; tmp >>= 1)
  93                         lc_shift++;
  94                 lc_mask = (1 << lc_shift) - 1;
  95
  96                 /* fix idx and old size to new shift */
  97                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  98                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  99
 100                 /* first shrink old cache to make more space */
 101                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 102                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 103                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 104
 105                 AFFS_I(inode)->i_lc_shift = lc_shift;
 106                 AFFS_I(inode)->i_lc_mask = lc_mask;
 107         }
 108
 109         /* fill cache to the needed index */
 110         i = AFFS_I(inode)->i_lc_size;
 111         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 112         for (; i <= lc_idx; i++) {
 113                 if (!i) {
 114                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 115                         continue;
 116                 }
 117                 key = AFFS_I(inode)->i_lc[i - 1];
 118                 j = AFFS_I(inode)->i_lc_mask + 1;
 119                 // unlock cache
 120                 for (; j > 0; j--) {
 121                         bh = affs_bread(sb, key);
 122                         if (!bh)
 123                                 goto err;
 124                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 125                         affs_brelse(bh);
 126                 }
 127                 // lock cache
 128                 AFFS_I(inode)->i_lc[i] = key;
 129         }
 130
 131         return 0;
 132
 133 err:
 134         // lock cache
 135         return -EIO;
 136 }
 137
 138 static struct buffer_head *
 139 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 140 {
 141         struct super_block *sb = inode->i_sb;
 142         struct buffer_head *new_bh;
 143         u32 blocknr, tmp;
 144
 145         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 146         if (!blocknr)
 147                 return ERR_PTR(-ENOSPC);
 148
 149         new_bh = affs_getzeroblk(sb, blocknr);
 150         if (!new_bh) {
 151                 affs_free_block(sb, blocknr);
 152                 return ERR_PTR(-EIO);
 153         }
 154
 155         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 156         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 157         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 158         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 159         affs_fix_checksum(sb, new_bh);
 160
 161         mark_buffer_dirty_inode(new_bh, inode);
 162
 163         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 164         if (tmp)
 165                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 166         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 167         affs_adjust_checksum(bh, blocknr - tmp);
 168         mark_buffer_dirty_inode(bh, inode);
 169
 170         AFFS_I(inode)->i_extcnt++;
 171         mark_inode_dirty(inode);
 172
 173         return new_bh;
 174 }
 175
 176 static inline struct buffer_head *
 177 affs_get_extblock(struct inode *inode, u32 ext)
 178 {
 179         /* inline the simplest case: same extended block as last time */
 180         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 181         if (ext == AFFS_I(inode)->i_ext_last)
 182                 atomic_inc(&bh->b_count);
 183         else
 184                 /* we have to do more (not inlined) */
 185                 bh = affs_get_extblock_slow(inode, ext);
 186
 187         return bh;
 188 }
 189
 190 static struct buffer_head *
 191 affs_get_extblock_slow(struct inode *inode, u32 ext)
 192 {
 193         struct super_block *sb = inode->i_sb;
 194         struct buffer_head *bh;
 195         u32 ext_key;
 196         u32 lc_idx, lc_off, ac_idx;
 197         u32 tmp, idx;
 198
 199         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 200                 /* read the next extended block from the current one */
 201                 bh = AFFS_I(inode)->i_ext_bh;
 202                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 203                 if (ext < AFFS_I(inode)->i_extcnt)
 204                         goto read_ext;
 205                 if (ext > AFFS_I(inode)->i_extcnt)
 206                         BUG();
 207                 bh = affs_alloc_extblock(inode, bh, ext);
 208                 if (IS_ERR(bh))
 209                         return bh;
 210                 goto store_ext;
 211         }
 212
 213         if (ext == 0) {
 214                 /* we seek back to the file header block */
 215                 ext_key = inode->i_ino;
 216                 goto read_ext;
 217         }
 218
 219         if (ext >= AFFS_I(inode)->i_extcnt) {
 220                 struct buffer_head *prev_bh;
 221
 222                 /* allocate a new extended block */
 223                 if (ext > AFFS_I(inode)->i_extcnt)
 224                         BUG();
 225
 226                 /* get previous extended block */
 227                 prev_bh = affs_get_extblock(inode, ext - 1);
 228                 if (IS_ERR(prev_bh))
 229                         return prev_bh;
 230                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 231                 affs_brelse(prev_bh);
 232                 if (IS_ERR(bh))
 233                         return bh;
 234                 goto store_ext;
 235         }
 236
 237 again:
 238         /* check if there is an extended cache and whether it's large enough */
 239         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 240         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 241
 242         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 243                 int err;
 244
 245                 err = affs_grow_extcache(inode, lc_idx);
 246                 if (err)
 247                         return ERR_PTR(err);
 248                 goto again;
 249         }
 250
 251         /* every n'th key we find in the linear cache */
 252         if (!lc_off) {
 253                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 254                 goto read_ext;
 255         }
 256
 257         /* maybe it's still in the associative cache */
 258         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 259         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 260                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 261                 goto read_ext;
 262         }
 263
 264         /* try to find one of the previous extended blocks */
 265         tmp = ext;
 266         idx = ac_idx;
 267         while (--tmp, --lc_off > 0) {
 268                 idx = (idx - 1) & AFFS_AC_MASK;
 269                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 270                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 271                         goto find_ext;
 272                 }
 273         }
 274
 275         /* fall back to the linear cache */
 276         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 277 find_ext:
 278         /* read all extended blocks until we find the one we need */
 279         //unlock cache
 280         do {
 281                 bh = affs_bread(sb, ext_key);
 282                 if (!bh)
 283                         goto err_bread;
 284                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 285                 affs_brelse(bh);
 286                 tmp++;
 287         } while (tmp < ext);
 288         //lock cache
 289
 290         /* store it in the associative cache */
 291         // recalculate ac_idx?
 292         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 293         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 294
 295 read_ext:
 296         /* finally read the right extended block */
 297         //unlock cache
 298         bh = affs_bread(sb, ext_key);
 299         if (!bh)
 300                 goto err_bread;
 301         //lock cache
 302
 303 store_ext:
 304         /* release old cached extended block and store the new one */
 305         affs_brelse(AFFS_I(inode)->i_ext_bh);
 306         AFFS_I(inode)->i_ext_last = ext;
 307         AFFS_I(inode)->i_ext_bh = bh;
 308         atomic_inc(&bh->b_count);
 309
 310         return bh;
 311
 312 err_bread:
 313         affs_brelse(bh);
 314         return ERR_PTR(-EIO);
 315 }
 316
 317 static int
 318 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 319 {
 320         struct super_block      *sb = inode->i_sb;
 321         struct buffer_head      *ext_bh;
 322         u32                      ext;
 323
 324         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 325
 326
 327         if (block > (sector_t)0x7fffffffUL)
 328                 BUG();
 329
 330         if (block >= AFFS_I(inode)->i_blkcnt) {
 331                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 332                         goto err_big;
 333         } else
 334                 create = 0;
 335
 336         //lock cache
 337         affs_lock_ext(inode);
 338
 339         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 340         block -= ext * AFFS_SB(sb)->s_hashsize;
 341         ext_bh = affs_get_extblock(inode, ext);
 342         if (IS_ERR(ext_bh))
 343                 goto err_ext;
 344         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 345
 346         if (create) {
 347                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 348                 if (!blocknr)
 349                         goto err_alloc;
 350                 set_buffer_new(bh_result);
 351                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 352                 AFFS_I(inode)->i_blkcnt++;
 353
 354                 /* store new block */
 355                 if (bh_result->b_blocknr)
 356                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
 357                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 358                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 359                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 360                 bh_result->b_blocknr = blocknr;
 361
 362                 if (!block) {
 363                         /* insert first block into header block */
 364                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 365                         if (tmp)
 366                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 367                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 368                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 369                 }
 370         }
 371
 372         affs_brelse(ext_bh);
 373         //unlock cache
 374         affs_unlock_ext(inode);
 375         return 0;
 376
 377 err_big:
 378         affs_error(inode->i_sb,"get_block","strange block request %d", block);
 379         return -EIO;
 380 err_ext:
 381         // unlock cache
 382         affs_unlock_ext(inode);
 383         return PTR_ERR(ext_bh);
 384 err_alloc:
 385         brelse(ext_bh);
 386         clear_buffer_mapped(bh_result);
 387         bh_result->b_bdev = NULL;
 388         // unlock cache
 389         affs_unlock_ext(inode);
 390         return -ENOSPC;
 391 }
 392
 393 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 394 {
 395         return block_write_full_page(page, affs_get_block, wbc);
 396 }
 397 static int affs_readpage(struct file *file, struct page *page)
 398 {
 399         return block_read_full_page(page, affs_get_block);
 400 }
 401 static int affs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
 402 {
 403         return cont_prepare_write(page, from, to, affs_get_block,
 404                 &AFFS_I(page->mapping->host)->mmu_private);
 405 }
 406 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 407 {
 408         return generic_block_bmap(mapping,block,affs_get_block);
 409 }
 410 struct address_space_operations affs_aops = {
 411         .readpage = affs_readpage,
 412         .writepage = affs_writepage,
 413         .sync_page = block_sync_page,
 414         .prepare_write = affs_prepare_write,
 415         .commit_write = generic_commit_write,
 416         .bmap = _affs_bmap
 417 };
 418
 419 static inline struct buffer_head *
 420 affs_bread_ino(struct inode *inode, int block, int create)
 421 {
 422         struct buffer_head *bh, tmp_bh;
 423         int err;
 424
 425         tmp_bh.b_state = 0;
 426         err = affs_get_block(inode, block, &tmp_bh, create);
 427         if (!err) {
 428                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 429                 if (bh) {
 430                         bh->b_state |= tmp_bh.b_state;
 431                         return bh;
 432                 }
 433                 err = -EIO;
 434         }
 435         return ERR_PTR(err);
 436 }
 437
 438 static inline struct buffer_head *
 439 affs_getzeroblk_ino(struct inode *inode, int block)
 440 {
 441         struct buffer_head *bh, tmp_bh;
 442         int err;
 443
 444         tmp_bh.b_state = 0;
 445         err = affs_get_block(inode, block, &tmp_bh, 1);
 446         if (!err) {
 447                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 448                 if (bh) {
 449                         bh->b_state |= tmp_bh.b_state;
 450                         return bh;
 451                 }
 452                 err = -EIO;
 453         }
 454         return ERR_PTR(err);
 455 }
 456
 457 static inline struct buffer_head *
 458 affs_getemptyblk_ino(struct inode *inode, int block)
 459 {
 460         struct buffer_head *bh, tmp_bh;
 461         int err;
 462
 463         tmp_bh.b_state = 0;
 464         err = affs_get_block(inode, block, &tmp_bh, 1);
 465         if (!err) {
 466                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 467                 if (bh) {
 468                         bh->b_state |= tmp_bh.b_state;
 469                         return bh;
 470                 }
 471                 err = -EIO;
 472         }
 473         return ERR_PTR(err);
 474 }
 475
 476 static ssize_t
 477 affs_file_write(struct file *file, const char __user *buf,
 478                 size_t count, loff_t *ppos)
 479 {
 480         ssize_t retval;
 481
 482         retval = generic_file_write (file, buf, count, ppos);
 483         if (retval >0) {
 484                 struct inode *inode = file->f_dentry->d_inode;
 485                 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
 486                 mark_inode_dirty(inode);
 487         }
 488         return retval;
 489 }
 490
 491 static int
 492 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 493 {
 494         struct inode *inode = page->mapping->host;
 495         struct super_block *sb = inode->i_sb;
 496         struct buffer_head *bh;
 497         char *data;
 498         u32 bidx, boff, bsize;
 499         u32 tmp;
 500
 501         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 502         if (from > to || to > PAGE_CACHE_SIZE)
 503                 BUG();
 504         kmap(page);
 505         data = page_address(page);
 506         bsize = AFFS_SB(sb)->s_data_blksize;
 507         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 508         bidx = tmp / bsize;
 509         boff = tmp % bsize;
 510
 511         while (from < to) {
 512                 bh = affs_bread_ino(inode, bidx, 0);
 513                 if (IS_ERR(bh))
 514                         return PTR_ERR(bh);
 515                 tmp = min(bsize - boff, to - from);
 516                 if (from + tmp > to || tmp > bsize)
 517                         BUG();
 518                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 519                 affs_brelse(bh);
 520                 bidx++;
 521                 from += tmp;
 522                 boff = 0;
 523         }
 524         flush_dcache_page(page);
 525         kunmap(page);
 526         return 0;
 527 }
 528
 529 static int
 530 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 531 {
 532         struct super_block *sb = inode->i_sb;
 533         struct buffer_head *bh, *prev_bh;
 534         u32 bidx, boff;
 535         u32 size, bsize;
 536         u32 tmp;
 537
 538         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 539         bsize = AFFS_SB(sb)->s_data_blksize;
 540         bh = NULL;
 541         size = AFFS_I(inode)->mmu_private;
 542         bidx = size / bsize;
 543         boff = size % bsize;
 544         if (boff) {
 545                 bh = affs_bread_ino(inode, bidx, 0);
 546                 if (IS_ERR(bh))
 547                         return PTR_ERR(bh);
 548                 tmp = min(bsize - boff, newsize - size);
 549                 if (boff + tmp > bsize || tmp > bsize)
 550                         BUG();
 551                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 552                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
 553                 affs_fix_checksum(sb, bh);
 554                 mark_buffer_dirty_inode(bh, inode);
 555                 size += tmp;
 556                 bidx++;
 557         } else if (bidx) {
 558                 bh = affs_bread_ino(inode, bidx - 1, 0);
 559                 if (IS_ERR(bh))
 560                         return PTR_ERR(bh);
 561         }
 562
 563         while (size < newsize) {
 564                 prev_bh = bh;
 565                 bh = affs_getzeroblk_ino(inode, bidx);
 566                 if (IS_ERR(bh))
 567                         goto out;
 568                 tmp = min(bsize, newsize - size);
 569                 if (tmp > bsize)
 570                         BUG();
 571                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 572                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 573                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 574                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 575                 affs_fix_checksum(sb, bh);
 576                 bh->b_state &= ~(1UL << BH_New);
 577                 mark_buffer_dirty_inode(bh, inode);
 578                 if (prev_bh) {
 579                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 580                         if (tmp)
 581                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 582                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 583                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 584                         mark_buffer_dirty_inode(prev_bh, inode);
 585                         affs_brelse(prev_bh);
 586                 }
 587                 size += bsize;
 588                 bidx++;
 589         }
 590         affs_brelse(bh);
 591         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 592         return 0;
 593
 594 out:
 595         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 596         return PTR_ERR(bh);
 597 }
 598
 599 static int
 600 affs_readpage_ofs(struct file *file, struct page *page)
 601 {
 602         struct inode *inode = page->mapping->host;
 603         u32 to;
 604         int err;
 605
 606         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 607         to = PAGE_CACHE_SIZE;
 608         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 609                 to = inode->i_size & ~PAGE_CACHE_MASK;
 610                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 611         }
 612
 613         err = affs_do_readpage_ofs(file, page, 0, to);
 614         if (!err)
 615                 SetPageUptodate(page);
 616         unlock_page(page);
 617         return err;
 618 }
 619
 620 static int affs_prepare_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 621 {
 622         struct inode *inode = page->mapping->host;
 623         u32 size, offset;
 624         u32 tmp;
 625         int err = 0;
 626
 627         pr_debug("AFFS: prepare_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 628         offset = page->index << PAGE_CACHE_SHIFT;
 629         if (offset + from > AFFS_I(inode)->mmu_private) {
 630                 err = affs_extent_file_ofs(inode, offset + from);
 631                 if (err)
 632                         return err;
 633         }
 634         size = inode->i_size;
 635
 636         if (PageUptodate(page))
 637                 return 0;
 638
 639         if (from) {
 640                 err = affs_do_readpage_ofs(file, page, 0, from);
 641                 if (err)
 642                         return err;
 643         }
 644         if (to < PAGE_CACHE_SIZE) {
 645                 char *kaddr = kmap_atomic(page, KM_USER0);
 646
 647                 memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
 648                 flush_dcache_page(page);
 649                 kunmap_atomic(kaddr, KM_USER0);
 650                 if (size > offset + to) {
 651                         if (size < offset + PAGE_CACHE_SIZE)
 652                                 tmp = size & ~PAGE_CACHE_MASK;
 653                         else
 654                                 tmp = PAGE_CACHE_SIZE;
 655                         err = affs_do_readpage_ofs(file, page, to, tmp);
 656                 }
 657         }
 658         return err;
 659 }
 660
 661 static int affs_commit_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 662 {
 663         struct inode *inode = page->mapping->host;
 664         struct super_block *sb = inode->i_sb;
 665         struct buffer_head *bh, *prev_bh;
 666         char *data;
 667         u32 bidx, boff, bsize;
 668         u32 tmp;
 669         int written;
 670
 671         pr_debug("AFFS: commit_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 672         bsize = AFFS_SB(sb)->s_data_blksize;
 673         data = page_address(page);
 674
 675         bh = NULL;
 676         written = 0;
 677         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 678         bidx = tmp / bsize;
 679         boff = tmp % bsize;
 680         if (boff) {
 681                 bh = affs_bread_ino(inode, bidx, 0);
 682                 if (IS_ERR(bh))
 683                         return PTR_ERR(bh);
 684                 tmp = min(bsize - boff, to - from);
 685                 if (boff + tmp > bsize || tmp > bsize)
 686                         BUG();
 687                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 688                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
 689                 affs_fix_checksum(sb, bh);
 690                 mark_buffer_dirty_inode(bh, inode);
 691                 written += tmp;
 692                 from += tmp;
 693                 bidx++;
 694         } else if (bidx) {
 695                 bh = affs_bread_ino(inode, bidx - 1, 0);
 696                 if (IS_ERR(bh))
 697                         return PTR_ERR(bh);
 698         }
 699         while (from + bsize <= to) {
 700                 prev_bh = bh;
 701                 bh = affs_getemptyblk_ino(inode, bidx);
 702                 if (IS_ERR(bh))
 703                         goto out;
 704                 memcpy(AFFS_DATA(bh), data + from, bsize);
 705                 if (buffer_new(bh)) {
 706                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 707                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 708                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 709                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 710                         AFFS_DATA_HEAD(bh)->next = 0;
 711                         bh->b_state &= ~(1UL << BH_New);
 712                         if (prev_bh) {
 713                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 714                                 if (tmp)
 715                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 716                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 717                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 718                                 mark_buffer_dirty_inode(prev_bh, inode);
 719                         }
 720                 }
 721                 affs_brelse(prev_bh);
 722                 affs_fix_checksum(sb, bh);
 723                 mark_buffer_dirty_inode(bh, inode);
 724                 written += bsize;
 725                 from += bsize;
 726                 bidx++;
 727         }
 728         if (from < to) {
 729                 prev_bh = bh;
 730                 bh = affs_bread_ino(inode, bidx, 1);
 731                 if (IS_ERR(bh))
 732                         goto out;
 733                 tmp = min(bsize, to - from);
 734                 if (tmp > bsize)
 735                         BUG();
 736                 memcpy(AFFS_DATA(bh), data + from, tmp);
 737                 if (buffer_new(bh)) {
 738                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 739                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 740                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 741                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 742                         AFFS_DATA_HEAD(bh)->next = 0;
 743                         bh->b_state &= ~(1UL << BH_New);
 744                         if (prev_bh) {
 745                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 746                                 if (tmp)
 747                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 748                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 749                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 750                                 mark_buffer_dirty_inode(prev_bh, inode);
 751                         }
 752                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 753                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 754                 affs_brelse(prev_bh);
 755                 affs_fix_checksum(sb, bh);
 756                 mark_buffer_dirty_inode(bh, inode);
 757                 written += tmp;
 758                 from += tmp;
 759                 bidx++;
 760         }
 761         SetPageUptodate(page);
 762
 763 done:
 764         affs_brelse(bh);
 765         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 766         if (tmp > inode->i_size)
 767                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 768
 769         return written;
 770
 771 out:
 772         bh = prev_bh;
 773         if (!written)
 774                 written = PTR_ERR(bh);
 775         goto done;
 776 }
 777
 778 struct address_space_operations affs_aops_ofs = {
 779         .readpage = affs_readpage_ofs,
 780         //.writepage = affs_writepage_ofs,
 781         //.sync_page = affs_sync_page_ofs,
 782         .prepare_write = affs_prepare_write_ofs,
 783         .commit_write = affs_commit_write_ofs
 784 };
 785
 786 /* Free any preallocated blocks. */
 787
 788 void
 789 affs_free_prealloc(struct inode *inode)
 790 {
 791         struct super_block *sb = inode->i_sb;
 792
 793         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 794
 795         while (AFFS_I(inode)->i_pa_cnt) {
 796                 AFFS_I(inode)->i_pa_cnt--;
 797                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 798         }
 799 }
 800
 801 /* Truncate (or enlarge) a file to the requested size. */
 802
 803 void
 804 affs_truncate(struct inode *inode)
 805 {
 806         struct super_block *sb = inode->i_sb;
 807         u32 ext, ext_key;
 808         u32 last_blk, blkcnt, blk;
 809         u32 size;
 810         struct buffer_head *ext_bh;
 811         int i;
 812
 813         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 814                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 815
 816         last_blk = 0;
 817         ext = 0;
 818         if (inode->i_size) {
 819                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 820                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 821         }
 822
 823         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 824                 struct address_space *mapping = inode->i_mapping;
 825                 struct page *page;
 826                 u32 size = inode->i_size - 1;
 827                 int res;
 828
 829                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
 830                 if (!page)
 831                         return;
 832                 size = (size & (PAGE_CACHE_SIZE - 1)) + 1;
 833                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
 834                 if (!res)
 835                         res = mapping->a_ops->commit_write(NULL, page, size, size);
 836                 unlock_page(page);
 837                 page_cache_release(page);
 838                 mark_inode_dirty(inode);
 839                 return;
 840         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 841                 return;
 842
 843         // lock cache
 844         ext_bh = affs_get_extblock(inode, ext);
 845         if (IS_ERR(ext_bh)) {
 846                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 847                              ext, PTR_ERR(ext_bh));
 848                 return;
 849         }
 850         if (AFFS_I(inode)->i_lc) {
 851                 /* clear linear cache */
 852                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 853                 if (AFFS_I(inode)->i_lc_size > i) {
 854                         AFFS_I(inode)->i_lc_size = i;
 855                         for (; i < AFFS_LC_SIZE; i++)
 856                                 AFFS_I(inode)->i_lc[i] = 0;
 857                 }
 858                 /* clear associative cache */
 859                 for (i = 0; i < AFFS_AC_SIZE; i++)
 860                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 861                                 AFFS_I(inode)->i_ac[i].ext = 0;
 862         }
 863         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 864
 865         blkcnt = AFFS_I(inode)->i_blkcnt;
 866         i = 0;
 867         blk = last_blk;
 868         if (inode->i_size) {
 869                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 870                 blk++;
 871         } else
 872                 AFFS_HEAD(ext_bh)->first_data = 0;
 873         size = AFFS_SB(sb)->s_hashsize;
 874         if (size > blkcnt - blk + i)
 875                 size = blkcnt - blk + i;
 876         for (; i < size; i++, blk++) {
 877                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 878                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 879         }
 880         AFFS_TAIL(sb, ext_bh)->extension = 0;
 881         affs_fix_checksum(sb, ext_bh);
 882         mark_buffer_dirty_inode(ext_bh, inode);
 883         affs_brelse(ext_bh);
 884
 885         if (inode->i_size) {
 886                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 887                 AFFS_I(inode)->i_extcnt = ext + 1;
 888                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 889                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 890                         u32 tmp;
 891                         if (IS_ERR(ext_bh)) {
 892                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 893                                              ext, PTR_ERR(ext_bh));
 894                                 return;
 895                         }
 896                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 897                         AFFS_DATA_HEAD(bh)->next = 0;
 898                         affs_adjust_checksum(bh, -tmp);
 899                         affs_brelse(bh);
 900                 }
 901         } else {
 902                 AFFS_I(inode)->i_blkcnt = 0;
 903                 AFFS_I(inode)->i_extcnt = 1;
 904         }
 905         AFFS_I(inode)->mmu_private = inode->i_size;
 906         // unlock cache
 907
 908         while (ext_key) {
 909                 ext_bh = affs_bread(sb, ext_key);
 910                 size = AFFS_SB(sb)->s_hashsize;
 911                 if (size > blkcnt - blk)
 912                         size = blkcnt - blk;
 913                 for (i = 0; i < size; i++, blk++)
 914                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 915                 affs_free_block(sb, ext_key);
 916                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 917                 affs_brelse(ext_bh);
 918         }
 919         affs_free_prealloc(inode);
 920 }