fs/affs/file.c

   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          = affs_file_fsync,
  38         .splice_read    = generic_file_splice_read,
  39 };
  40
  41 const struct inode_operations affs_file_inode_operations = {
  42         .setattr        = affs_notify_change,
  43 };
  44
  45 static int
  46 affs_file_open(struct inode *inode, struct file *filp)
  47 {
  48         pr_debug("AFFS: open(%lu,%d)\n",
  49                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  50         atomic_inc(&AFFS_I(inode)->i_opencnt);
  51         return 0;
  52 }
  53
  54 static int
  55 affs_file_release(struct inode *inode, struct file *filp)
  56 {
  57         pr_debug("AFFS: release(%lu, %d)\n",
  58                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  59
  60         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  61                 mutex_lock(&inode->i_mutex);
  62                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  63                         affs_truncate(inode);
  64                 affs_free_prealloc(inode);
  65                 mutex_unlock(&inode->i_mutex);
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int
  72 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  73 {
  74         struct super_block      *sb = inode->i_sb;
  75         struct buffer_head      *bh;
  76         u32 lc_max;
  77         int i, j, key;
  78
  79         if (!AFFS_I(inode)->i_lc) {
  80                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  81                 if (!ptr)
  82                         return -ENOMEM;
  83                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  84                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  85         }
  86
  87         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  88
  89         if (AFFS_I(inode)->i_extcnt > lc_max) {
  90                 u32 lc_shift, lc_mask, tmp, off;
  91
  92                 /* need to recalculate linear cache, start from old size */
  93                 lc_shift = AFFS_I(inode)->i_lc_shift;
  94                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  95                 for (; tmp; tmp >>= 1)
  96                         lc_shift++;
  97                 lc_mask = (1 << lc_shift) - 1;
  98
  99                 /* fix idx and old size to new shift */
 100                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 101                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 102
 103                 /* first shrink old cache to make more space */
 104                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 105                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 106                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 107
 108                 AFFS_I(inode)->i_lc_shift = lc_shift;
 109                 AFFS_I(inode)->i_lc_mask = lc_mask;
 110         }
 111
 112         /* fill cache to the needed index */
 113         i = AFFS_I(inode)->i_lc_size;
 114         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 115         for (; i <= lc_idx; i++) {
 116                 if (!i) {
 117                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 118                         continue;
 119                 }
 120                 key = AFFS_I(inode)->i_lc[i - 1];
 121                 j = AFFS_I(inode)->i_lc_mask + 1;
 122                 // unlock cache
 123                 for (; j > 0; j--) {
 124                         bh = affs_bread(sb, key);
 125                         if (!bh)
 126                                 goto err;
 127                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 128                         affs_brelse(bh);
 129                 }
 130                 // lock cache
 131                 AFFS_I(inode)->i_lc[i] = key;
 132         }
 133
 134         return 0;
 135
 136 err:
 137         // lock cache
 138         return -EIO;
 139 }
 140
 141 static struct buffer_head *
 142 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 143 {
 144         struct super_block *sb = inode->i_sb;
 145         struct buffer_head *new_bh;
 146         u32 blocknr, tmp;
 147
 148         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 149         if (!blocknr)
 150                 return ERR_PTR(-ENOSPC);
 151
 152         new_bh = affs_getzeroblk(sb, blocknr);
 153         if (!new_bh) {
 154                 affs_free_block(sb, blocknr);
 155                 return ERR_PTR(-EIO);
 156         }
 157
 158         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 159         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 160         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 161         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 162         affs_fix_checksum(sb, new_bh);
 163
 164         mark_buffer_dirty_inode(new_bh, inode);
 165
 166         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 167         if (tmp)
 168                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 169         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 170         affs_adjust_checksum(bh, blocknr - tmp);
 171         mark_buffer_dirty_inode(bh, inode);
 172
 173         AFFS_I(inode)->i_extcnt++;
 174         mark_inode_dirty(inode);
 175
 176         return new_bh;
 177 }
 178
 179 static inline struct buffer_head *
 180 affs_get_extblock(struct inode *inode, u32 ext)
 181 {
 182         /* inline the simplest case: same extended block as last time */
 183         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 184         if (ext == AFFS_I(inode)->i_ext_last)
 185                 get_bh(bh);
 186         else
 187                 /* we have to do more (not inlined) */
 188                 bh = affs_get_extblock_slow(inode, ext);
 189
 190         return bh;
 191 }
 192
 193 static struct buffer_head *
 194 affs_get_extblock_slow(struct inode *inode, u32 ext)
 195 {
 196         struct super_block *sb = inode->i_sb;
 197         struct buffer_head *bh;
 198         u32 ext_key;
 199         u32 lc_idx, lc_off, ac_idx;
 200         u32 tmp, idx;
 201
 202         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 203                 /* read the next extended block from the current one */
 204                 bh = AFFS_I(inode)->i_ext_bh;
 205                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 206                 if (ext < AFFS_I(inode)->i_extcnt)
 207                         goto read_ext;
 208                 if (ext > AFFS_I(inode)->i_extcnt)
 209                         BUG();
 210                 bh = affs_alloc_extblock(inode, bh, ext);
 211                 if (IS_ERR(bh))
 212                         return bh;
 213                 goto store_ext;
 214         }
 215
 216         if (ext == 0) {
 217                 /* we seek back to the file header block */
 218                 ext_key = inode->i_ino;
 219                 goto read_ext;
 220         }
 221
 222         if (ext >= AFFS_I(inode)->i_extcnt) {
 223                 struct buffer_head *prev_bh;
 224
 225                 /* allocate a new extended block */
 226                 if (ext > AFFS_I(inode)->i_extcnt)
 227                         BUG();
 228
 229                 /* get previous extended block */
 230                 prev_bh = affs_get_extblock(inode, ext - 1);
 231                 if (IS_ERR(prev_bh))
 232                         return prev_bh;
 233                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 234                 affs_brelse(prev_bh);
 235                 if (IS_ERR(bh))
 236                         return bh;
 237                 goto store_ext;
 238         }
 239
 240 again:
 241         /* check if there is an extended cache and whether it's large enough */
 242         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 243         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 244
 245         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 246                 int err;
 247
 248                 err = affs_grow_extcache(inode, lc_idx);
 249                 if (err)
 250                         return ERR_PTR(err);
 251                 goto again;
 252         }
 253
 254         /* every n'th key we find in the linear cache */
 255         if (!lc_off) {
 256                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 257                 goto read_ext;
 258         }
 259
 260         /* maybe it's still in the associative cache */
 261         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 262         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 263                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 264                 goto read_ext;
 265         }
 266
 267         /* try to find one of the previous extended blocks */
 268         tmp = ext;
 269         idx = ac_idx;
 270         while (--tmp, --lc_off > 0) {
 271                 idx = (idx - 1) & AFFS_AC_MASK;
 272                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 273                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 274                         goto find_ext;
 275                 }
 276         }
 277
 278         /* fall back to the linear cache */
 279         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 280 find_ext:
 281         /* read all extended blocks until we find the one we need */
 282         //unlock cache
 283         do {
 284                 bh = affs_bread(sb, ext_key);
 285                 if (!bh)
 286                         goto err_bread;
 287                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 288                 affs_brelse(bh);
 289                 tmp++;
 290         } while (tmp < ext);
 291         //lock cache
 292
 293         /* store it in the associative cache */
 294         // recalculate ac_idx?
 295         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 296         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 297
 298 read_ext:
 299         /* finally read the right extended block */
 300         //unlock cache
 301         bh = affs_bread(sb, ext_key);
 302         if (!bh)
 303                 goto err_bread;
 304         //lock cache
 305
 306 store_ext:
 307         /* release old cached extended block and store the new one */
 308         affs_brelse(AFFS_I(inode)->i_ext_bh);
 309         AFFS_I(inode)->i_ext_last = ext;
 310         AFFS_I(inode)->i_ext_bh = bh;
 311         get_bh(bh);
 312
 313         return bh;
 314
 315 err_bread:
 316         affs_brelse(bh);
 317         return ERR_PTR(-EIO);
 318 }
 319
 320 static int
 321 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 322 {
 323         struct super_block      *sb = inode->i_sb;
 324         struct buffer_head      *ext_bh;
 325         u32                      ext;
 326
 327         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 328
 329         BUG_ON(block > (sector_t)0x7fffffffUL);
 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
 399 static int affs_readpage(struct file *file, struct page *page)
 400 {
 401         return block_read_full_page(page, affs_get_block);
 402 }
 403
 404 static void affs_write_failed(struct address_space *mapping, loff_t to)
 405 {
 406         struct inode *inode = mapping->host;
 407
 408         if (to > inode->i_size) {
 409                 truncate_pagecache(inode, to, inode->i_size);
 410                 affs_truncate(inode);
 411         }
 412 }
 413
 414 static int affs_write_begin(struct file *file, struct address_space *mapping,
 415                         loff_t pos, unsigned len, unsigned flags,
 416                         struct page **pagep, void **fsdata)
 417 {
 418         int ret;
 419
 420         *pagep = NULL;
 421         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 422                                 affs_get_block,
 423                                 &AFFS_I(mapping->host)->mmu_private);
 424         if (unlikely(ret))
 425                 affs_write_failed(mapping, pos + len);
 426
 427         return ret;
 428 }
 429
 430 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 431 {
 432         return generic_block_bmap(mapping,block,affs_get_block);
 433 }
 434
 435 const struct address_space_operations affs_aops = {
 436         .readpage = affs_readpage,
 437         .writepage = affs_writepage,
 438         .write_begin = affs_write_begin,
 439         .write_end = generic_write_end,
 440         .bmap = _affs_bmap
 441 };
 442
 443 static inline struct buffer_head *
 444 affs_bread_ino(struct inode *inode, int block, int create)
 445 {
 446         struct buffer_head *bh, tmp_bh;
 447         int err;
 448
 449         tmp_bh.b_state = 0;
 450         err = affs_get_block(inode, block, &tmp_bh, create);
 451         if (!err) {
 452                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 453                 if (bh) {
 454                         bh->b_state |= tmp_bh.b_state;
 455                         return bh;
 456                 }
 457                 err = -EIO;
 458         }
 459         return ERR_PTR(err);
 460 }
 461
 462 static inline struct buffer_head *
 463 affs_getzeroblk_ino(struct inode *inode, int block)
 464 {
 465         struct buffer_head *bh, tmp_bh;
 466         int err;
 467
 468         tmp_bh.b_state = 0;
 469         err = affs_get_block(inode, block, &tmp_bh, 1);
 470         if (!err) {
 471                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 472                 if (bh) {
 473                         bh->b_state |= tmp_bh.b_state;
 474                         return bh;
 475                 }
 476                 err = -EIO;
 477         }
 478         return ERR_PTR(err);
 479 }
 480
 481 static inline struct buffer_head *
 482 affs_getemptyblk_ino(struct inode *inode, int block)
 483 {
 484         struct buffer_head *bh, tmp_bh;
 485         int err;
 486
 487         tmp_bh.b_state = 0;
 488         err = affs_get_block(inode, block, &tmp_bh, 1);
 489         if (!err) {
 490                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 491                 if (bh) {
 492                         bh->b_state |= tmp_bh.b_state;
 493                         return bh;
 494                 }
 495                 err = -EIO;
 496         }
 497         return ERR_PTR(err);
 498 }
 499
 500 static int
 501 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 502 {
 503         struct inode *inode = page->mapping->host;
 504         struct super_block *sb = inode->i_sb;
 505         struct buffer_head *bh;
 506         char *data;
 507         u32 bidx, boff, bsize;
 508         u32 tmp;
 509
 510         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 511         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
 512         kmap(page);
 513         data = page_address(page);
 514         bsize = AFFS_SB(sb)->s_data_blksize;
 515         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 516         bidx = tmp / bsize;
 517         boff = tmp % bsize;
 518
 519         while (from < to) {
 520                 bh = affs_bread_ino(inode, bidx, 0);
 521                 if (IS_ERR(bh))
 522                         return PTR_ERR(bh);
 523                 tmp = min(bsize - boff, to - from);
 524                 BUG_ON(from + tmp > to || tmp > bsize);
 525                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 526                 affs_brelse(bh);
 527                 bidx++;
 528                 from += tmp;
 529                 boff = 0;
 530         }
 531         flush_dcache_page(page);
 532         kunmap(page);
 533         return 0;
 534 }
 535
 536 static int
 537 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 538 {
 539         struct super_block *sb = inode->i_sb;
 540         struct buffer_head *bh, *prev_bh;
 541         u32 bidx, boff;
 542         u32 size, bsize;
 543         u32 tmp;
 544
 545         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 546         bsize = AFFS_SB(sb)->s_data_blksize;
 547         bh = NULL;
 548         size = AFFS_I(inode)->mmu_private;
 549         bidx = size / bsize;
 550         boff = size % bsize;
 551         if (boff) {
 552                 bh = affs_bread_ino(inode, bidx, 0);
 553                 if (IS_ERR(bh))
 554                         return PTR_ERR(bh);
 555                 tmp = min(bsize - boff, newsize - size);
 556                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 557                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 558                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 559                 affs_fix_checksum(sb, bh);
 560                 mark_buffer_dirty_inode(bh, inode);
 561                 size += tmp;
 562                 bidx++;
 563         } else if (bidx) {
 564                 bh = affs_bread_ino(inode, bidx - 1, 0);
 565                 if (IS_ERR(bh))
 566                         return PTR_ERR(bh);
 567         }
 568
 569         while (size < newsize) {
 570                 prev_bh = bh;
 571                 bh = affs_getzeroblk_ino(inode, bidx);
 572                 if (IS_ERR(bh))
 573                         goto out;
 574                 tmp = min(bsize, newsize - size);
 575                 BUG_ON(tmp > bsize);
 576                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 577                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 578                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 579                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 580                 affs_fix_checksum(sb, bh);
 581                 bh->b_state &= ~(1UL << BH_New);
 582                 mark_buffer_dirty_inode(bh, inode);
 583                 if (prev_bh) {
 584                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 585                         if (tmp)
 586                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 587                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 588                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 589                         mark_buffer_dirty_inode(prev_bh, inode);
 590                         affs_brelse(prev_bh);
 591                 }
 592                 size += bsize;
 593                 bidx++;
 594         }
 595         affs_brelse(bh);
 596         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 597         return 0;
 598
 599 out:
 600         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 601         return PTR_ERR(bh);
 602 }
 603
 604 static int
 605 affs_readpage_ofs(struct file *file, struct page *page)
 606 {
 607         struct inode *inode = page->mapping->host;
 608         u32 to;
 609         int err;
 610
 611         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 612         to = PAGE_CACHE_SIZE;
 613         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 614                 to = inode->i_size & ~PAGE_CACHE_MASK;
 615                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 616         }
 617
 618         err = affs_do_readpage_ofs(file, page, 0, to);
 619         if (!err)
 620                 SetPageUptodate(page);
 621         unlock_page(page);
 622         return err;
 623 }
 624
 625 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 626                                 loff_t pos, unsigned len, unsigned flags,
 627                                 struct page **pagep, void **fsdata)
 628 {
 629         struct inode *inode = mapping->host;
 630         struct page *page;
 631         pgoff_t index;
 632         int err = 0;
 633
 634         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 635         if (pos > AFFS_I(inode)->mmu_private) {
 636                 /* XXX: this probably leaves a too-big i_size in case of
 637                  * failure. Should really be updating i_size at write_end time
 638                  */
 639                 err = affs_extent_file_ofs(inode, pos);
 640                 if (err)
 641                         return err;
 642         }
 643
 644         index = pos >> PAGE_CACHE_SHIFT;
 645         page = grab_cache_page_write_begin(mapping, index, flags);
 646         if (!page)
 647                 return -ENOMEM;
 648         *pagep = page;
 649
 650         if (PageUptodate(page))
 651                 return 0;
 652
 653         /* XXX: inefficient but safe in the face of short writes */
 654         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
 655         if (err) {
 656                 unlock_page(page);
 657                 page_cache_release(page);
 658         }
 659         return err;
 660 }
 661
 662 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 663                                 loff_t pos, unsigned len, unsigned copied,
 664                                 struct page *page, void *fsdata)
 665 {
 666         struct inode *inode = mapping->host;
 667         struct super_block *sb = inode->i_sb;
 668         struct buffer_head *bh, *prev_bh;
 669         char *data;
 670         u32 bidx, boff, bsize;
 671         unsigned from, to;
 672         u32 tmp;
 673         int written;
 674
 675         from = pos & (PAGE_CACHE_SIZE - 1);
 676         to = pos + len;
 677         /*
 678          * XXX: not sure if this can handle short copies (len < copied), but
 679          * we don't have to, because the page should always be uptodate here,
 680          * due to write_begin.
 681          */
 682
 683         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 684         bsize = AFFS_SB(sb)->s_data_blksize;
 685         data = page_address(page);
 686
 687         bh = NULL;
 688         written = 0;
 689         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 690         bidx = tmp / bsize;
 691         boff = tmp % bsize;
 692         if (boff) {
 693                 bh = affs_bread_ino(inode, bidx, 0);
 694                 if (IS_ERR(bh))
 695                         return PTR_ERR(bh);
 696                 tmp = min(bsize - boff, to - from);
 697                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 698                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 699                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 700                 affs_fix_checksum(sb, bh);
 701                 mark_buffer_dirty_inode(bh, inode);
 702                 written += tmp;
 703                 from += tmp;
 704                 bidx++;
 705         } else if (bidx) {
 706                 bh = affs_bread_ino(inode, bidx - 1, 0);
 707                 if (IS_ERR(bh))
 708                         return PTR_ERR(bh);
 709         }
 710         while (from + bsize <= to) {
 711                 prev_bh = bh;
 712                 bh = affs_getemptyblk_ino(inode, bidx);
 713                 if (IS_ERR(bh))
 714                         goto out;
 715                 memcpy(AFFS_DATA(bh), data + from, bsize);
 716                 if (buffer_new(bh)) {
 717                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 718                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 719                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 720                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 721                         AFFS_DATA_HEAD(bh)->next = 0;
 722                         bh->b_state &= ~(1UL << BH_New);
 723                         if (prev_bh) {
 724                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 725                                 if (tmp)
 726                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 727                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 728                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 729                                 mark_buffer_dirty_inode(prev_bh, inode);
 730                         }
 731                 }
 732                 affs_brelse(prev_bh);
 733                 affs_fix_checksum(sb, bh);
 734                 mark_buffer_dirty_inode(bh, inode);
 735                 written += bsize;
 736                 from += bsize;
 737                 bidx++;
 738         }
 739         if (from < to) {
 740                 prev_bh = bh;
 741                 bh = affs_bread_ino(inode, bidx, 1);
 742                 if (IS_ERR(bh))
 743                         goto out;
 744                 tmp = min(bsize, to - from);
 745                 BUG_ON(tmp > bsize);
 746                 memcpy(AFFS_DATA(bh), data + from, tmp);
 747                 if (buffer_new(bh)) {
 748                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 749                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 750                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 751                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 752                         AFFS_DATA_HEAD(bh)->next = 0;
 753                         bh->b_state &= ~(1UL << BH_New);
 754                         if (prev_bh) {
 755                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 756                                 if (tmp)
 757                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 758                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 759                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 760                                 mark_buffer_dirty_inode(prev_bh, inode);
 761                         }
 762                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 763                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 764                 affs_brelse(prev_bh);
 765                 affs_fix_checksum(sb, bh);
 766                 mark_buffer_dirty_inode(bh, inode);
 767                 written += tmp;
 768                 from += tmp;
 769                 bidx++;
 770         }
 771         SetPageUptodate(page);
 772
 773 done:
 774         affs_brelse(bh);
 775         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 776         if (tmp > inode->i_size)
 777                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 778
 779         unlock_page(page);
 780         page_cache_release(page);
 781
 782         return written;
 783
 784 out:
 785         bh = prev_bh;
 786         if (!written)
 787                 written = PTR_ERR(bh);
 788         goto done;
 789 }
 790
 791 const struct address_space_operations affs_aops_ofs = {
 792         .readpage = affs_readpage_ofs,
 793         //.writepage = affs_writepage_ofs,
 794         .write_begin = affs_write_begin_ofs,
 795         .write_end = affs_write_end_ofs
 796 };
 797
 798 /* Free any preallocated blocks. */
 799
 800 void
 801 affs_free_prealloc(struct inode *inode)
 802 {
 803         struct super_block *sb = inode->i_sb;
 804
 805         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 806
 807         while (AFFS_I(inode)->i_pa_cnt) {
 808                 AFFS_I(inode)->i_pa_cnt--;
 809                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 810         }
 811 }
 812
 813 /* Truncate (or enlarge) a file to the requested size. */
 814
 815 void
 816 affs_truncate(struct inode *inode)
 817 {
 818         struct super_block *sb = inode->i_sb;
 819         u32 ext, ext_key;
 820         u32 last_blk, blkcnt, blk;
 821         u32 size;
 822         struct buffer_head *ext_bh;
 823         int i;
 824
 825         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 826                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 827
 828         last_blk = 0;
 829         ext = 0;
 830         if (inode->i_size) {
 831                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 832                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 833         }
 834
 835         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 836                 struct address_space *mapping = inode->i_mapping;
 837                 struct page *page;
 838                 void *fsdata;
 839                 u32 size = inode->i_size;
 840                 int res;
 841
 842                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 843                 if (!res)
 844                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 845                 else
 846                         inode->i_size = AFFS_I(inode)->mmu_private;
 847                 mark_inode_dirty(inode);
 848                 return;
 849         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 850                 return;
 851
 852         // lock cache
 853         ext_bh = affs_get_extblock(inode, ext);
 854         if (IS_ERR(ext_bh)) {
 855                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 856                              ext, PTR_ERR(ext_bh));
 857                 return;
 858         }
 859         if (AFFS_I(inode)->i_lc) {
 860                 /* clear linear cache */
 861                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 862                 if (AFFS_I(inode)->i_lc_size > i) {
 863                         AFFS_I(inode)->i_lc_size = i;
 864                         for (; i < AFFS_LC_SIZE; i++)
 865                                 AFFS_I(inode)->i_lc[i] = 0;
 866                 }
 867                 /* clear associative cache */
 868                 for (i = 0; i < AFFS_AC_SIZE; i++)
 869                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 870                                 AFFS_I(inode)->i_ac[i].ext = 0;
 871         }
 872         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 873
 874         blkcnt = AFFS_I(inode)->i_blkcnt;
 875         i = 0;
 876         blk = last_blk;
 877         if (inode->i_size) {
 878                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 879                 blk++;
 880         } else
 881                 AFFS_HEAD(ext_bh)->first_data = 0;
 882         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 883         size = AFFS_SB(sb)->s_hashsize;
 884         if (size > blkcnt - blk + i)
 885                 size = blkcnt - blk + i;
 886         for (; i < size; i++, blk++) {
 887                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 888                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 889         }
 890         AFFS_TAIL(sb, ext_bh)->extension = 0;
 891         affs_fix_checksum(sb, ext_bh);
 892         mark_buffer_dirty_inode(ext_bh, inode);
 893         affs_brelse(ext_bh);
 894
 895         if (inode->i_size) {
 896                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 897                 AFFS_I(inode)->i_extcnt = ext + 1;
 898                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 899                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 900                         u32 tmp;
 901                         if (IS_ERR(bh)) {
 902                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 903                                              ext, PTR_ERR(bh));
 904                                 return;
 905                         }
 906                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 907                         AFFS_DATA_HEAD(bh)->next = 0;
 908                         affs_adjust_checksum(bh, -tmp);
 909                         affs_brelse(bh);
 910                 }
 911         } else {
 912                 AFFS_I(inode)->i_blkcnt = 0;
 913                 AFFS_I(inode)->i_extcnt = 1;
 914         }
 915         AFFS_I(inode)->mmu_private = inode->i_size;
 916         // unlock cache
 917
 918         while (ext_key) {
 919                 ext_bh = affs_bread(sb, ext_key);
 920                 size = AFFS_SB(sb)->s_hashsize;
 921                 if (size > blkcnt - blk)
 922                         size = blkcnt - blk;
 923                 for (i = 0; i < size; i++, blk++)
 924                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 925                 affs_free_block(sb, ext_key);
 926                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 927                 affs_brelse(ext_bh);
 928         }
 929         affs_free_prealloc(inode);
 930 }
 931
 932 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 933 {
 934         struct inode *inode = filp->f_mapping->host;
 935         int ret, err;
 936
 937         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 938         if (err)
 939                 return err;
 940
 941         mutex_lock(&inode->i_mutex);
 942         ret = write_inode_now(inode, 0);
 943         err = sync_blockdev(inode->i_sb->s_bdev);
 944         if (!ret)
 945                 ret = err;
 946         mutex_unlock(&inode->i_mutex);
 947         return ret;
 948 }