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, 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 page *page, 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         unsigned pos = 0;
 508         u32 bidx, boff, bsize;
 509         u32 tmp;
 510
 511         pr_debug("AFFS: read_page(%u, %ld, 0, %d)\n", (u32)inode->i_ino,
 512                  page->index, to);
 513         BUG_ON(to > PAGE_CACHE_SIZE);
 514         kmap(page);
 515         data = page_address(page);
 516         bsize = AFFS_SB(sb)->s_data_blksize;
 517         tmp = page->index << PAGE_CACHE_SHIFT;
 518         bidx = tmp / bsize;
 519         boff = tmp % bsize;
 520
 521         while (pos < to) {
 522                 bh = affs_bread_ino(inode, bidx, 0);
 523                 if (IS_ERR(bh))
 524                         return PTR_ERR(bh);
 525                 tmp = min(bsize - boff, to - pos);
 526                 BUG_ON(pos + tmp > to || tmp > bsize);
 527                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 528                 affs_brelse(bh);
 529                 bidx++;
 530                 pos += tmp;
 531                 boff = 0;
 532         }
 533         flush_dcache_page(page);
 534         kunmap(page);
 535         return 0;
 536 }
 537
 538 static int
 539 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 540 {
 541         struct super_block *sb = inode->i_sb;
 542         struct buffer_head *bh, *prev_bh;
 543         u32 bidx, boff;
 544         u32 size, bsize;
 545         u32 tmp;
 546
 547         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 548         bsize = AFFS_SB(sb)->s_data_blksize;
 549         bh = NULL;
 550         size = AFFS_I(inode)->mmu_private;
 551         bidx = size / bsize;
 552         boff = size % bsize;
 553         if (boff) {
 554                 bh = affs_bread_ino(inode, bidx, 0);
 555                 if (IS_ERR(bh))
 556                         return PTR_ERR(bh);
 557                 tmp = min(bsize - boff, newsize - size);
 558                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 559                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 560                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 561                 affs_fix_checksum(sb, bh);
 562                 mark_buffer_dirty_inode(bh, inode);
 563                 size += tmp;
 564                 bidx++;
 565         } else if (bidx) {
 566                 bh = affs_bread_ino(inode, bidx - 1, 0);
 567                 if (IS_ERR(bh))
 568                         return PTR_ERR(bh);
 569         }
 570
 571         while (size < newsize) {
 572                 prev_bh = bh;
 573                 bh = affs_getzeroblk_ino(inode, bidx);
 574                 if (IS_ERR(bh))
 575                         goto out;
 576                 tmp = min(bsize, newsize - size);
 577                 BUG_ON(tmp > bsize);
 578                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 579                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 580                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 581                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 582                 affs_fix_checksum(sb, bh);
 583                 bh->b_state &= ~(1UL << BH_New);
 584                 mark_buffer_dirty_inode(bh, inode);
 585                 if (prev_bh) {
 586                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 587                         if (tmp)
 588                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 589                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 590                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 591                         mark_buffer_dirty_inode(prev_bh, inode);
 592                         affs_brelse(prev_bh);
 593                 }
 594                 size += bsize;
 595                 bidx++;
 596         }
 597         affs_brelse(bh);
 598         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 599         return 0;
 600
 601 out:
 602         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 603         return PTR_ERR(bh);
 604 }
 605
 606 static int
 607 affs_readpage_ofs(struct file *file, struct page *page)
 608 {
 609         struct inode *inode = page->mapping->host;
 610         u32 to;
 611         int err;
 612
 613         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 614         to = PAGE_CACHE_SIZE;
 615         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 616                 to = inode->i_size & ~PAGE_CACHE_MASK;
 617                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 618         }
 619
 620         err = affs_do_readpage_ofs(page, to);
 621         if (!err)
 622                 SetPageUptodate(page);
 623         unlock_page(page);
 624         return err;
 625 }
 626
 627 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 628                                 loff_t pos, unsigned len, unsigned flags,
 629                                 struct page **pagep, void **fsdata)
 630 {
 631         struct inode *inode = mapping->host;
 632         struct page *page;
 633         pgoff_t index;
 634         int err = 0;
 635
 636         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 637         if (pos > AFFS_I(inode)->mmu_private) {
 638                 /* XXX: this probably leaves a too-big i_size in case of
 639                  * failure. Should really be updating i_size at write_end time
 640                  */
 641                 err = affs_extent_file_ofs(inode, pos);
 642                 if (err)
 643                         return err;
 644         }
 645
 646         index = pos >> PAGE_CACHE_SHIFT;
 647         page = grab_cache_page_write_begin(mapping, index, flags);
 648         if (!page)
 649                 return -ENOMEM;
 650         *pagep = page;
 651
 652         if (PageUptodate(page))
 653                 return 0;
 654
 655         /* XXX: inefficient but safe in the face of short writes */
 656         err = affs_do_readpage_ofs(page, PAGE_CACHE_SIZE);
 657         if (err) {
 658                 unlock_page(page);
 659                 page_cache_release(page);
 660         }
 661         return err;
 662 }
 663
 664 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 665                                 loff_t pos, unsigned len, unsigned copied,
 666                                 struct page *page, void *fsdata)
 667 {
 668         struct inode *inode = mapping->host;
 669         struct super_block *sb = inode->i_sb;
 670         struct buffer_head *bh, *prev_bh;
 671         char *data;
 672         u32 bidx, boff, bsize;
 673         unsigned from, to;
 674         u32 tmp;
 675         int written;
 676
 677         from = pos & (PAGE_CACHE_SIZE - 1);
 678         to = pos + len;
 679         /*
 680          * XXX: not sure if this can handle short copies (len < copied), but
 681          * we don't have to, because the page should always be uptodate here,
 682          * due to write_begin.
 683          */
 684
 685         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 686         bsize = AFFS_SB(sb)->s_data_blksize;
 687         data = page_address(page);
 688
 689         bh = NULL;
 690         written = 0;
 691         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 692         bidx = tmp / bsize;
 693         boff = tmp % bsize;
 694         if (boff) {
 695                 bh = affs_bread_ino(inode, bidx, 0);
 696                 if (IS_ERR(bh))
 697                         return PTR_ERR(bh);
 698                 tmp = min(bsize - boff, to - from);
 699                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 700                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 701                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 702                 affs_fix_checksum(sb, bh);
 703                 mark_buffer_dirty_inode(bh, inode);
 704                 written += tmp;
 705                 from += tmp;
 706                 bidx++;
 707         } else if (bidx) {
 708                 bh = affs_bread_ino(inode, bidx - 1, 0);
 709                 if (IS_ERR(bh))
 710                         return PTR_ERR(bh);
 711         }
 712         while (from + bsize <= to) {
 713                 prev_bh = bh;
 714                 bh = affs_getemptyblk_ino(inode, bidx);
 715                 if (IS_ERR(bh))
 716                         goto out;
 717                 memcpy(AFFS_DATA(bh), data + from, bsize);
 718                 if (buffer_new(bh)) {
 719                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 720                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 721                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 722                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 723                         AFFS_DATA_HEAD(bh)->next = 0;
 724                         bh->b_state &= ~(1UL << BH_New);
 725                         if (prev_bh) {
 726                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 727                                 if (tmp)
 728                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 729                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 730                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 731                                 mark_buffer_dirty_inode(prev_bh, inode);
 732                         }
 733                 }
 734                 affs_brelse(prev_bh);
 735                 affs_fix_checksum(sb, bh);
 736                 mark_buffer_dirty_inode(bh, inode);
 737                 written += bsize;
 738                 from += bsize;
 739                 bidx++;
 740         }
 741         if (from < to) {
 742                 prev_bh = bh;
 743                 bh = affs_bread_ino(inode, bidx, 1);
 744                 if (IS_ERR(bh))
 745                         goto out;
 746                 tmp = min(bsize, to - from);
 747                 BUG_ON(tmp > bsize);
 748                 memcpy(AFFS_DATA(bh), data + from, tmp);
 749                 if (buffer_new(bh)) {
 750                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 751                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 752                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 753                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 754                         AFFS_DATA_HEAD(bh)->next = 0;
 755                         bh->b_state &= ~(1UL << BH_New);
 756                         if (prev_bh) {
 757                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 758                                 if (tmp)
 759                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 760                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 761                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 762                                 mark_buffer_dirty_inode(prev_bh, inode);
 763                         }
 764                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 765                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 766                 affs_brelse(prev_bh);
 767                 affs_fix_checksum(sb, bh);
 768                 mark_buffer_dirty_inode(bh, inode);
 769                 written += tmp;
 770                 from += tmp;
 771                 bidx++;
 772         }
 773         SetPageUptodate(page);
 774
 775 done:
 776         affs_brelse(bh);
 777         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 778         if (tmp > inode->i_size)
 779                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 780
 781         unlock_page(page);
 782         page_cache_release(page);
 783
 784         return written;
 785
 786 out:
 787         bh = prev_bh;
 788         if (!written)
 789                 written = PTR_ERR(bh);
 790         goto done;
 791 }
 792
 793 const struct address_space_operations affs_aops_ofs = {
 794         .readpage = affs_readpage_ofs,
 795         //.writepage = affs_writepage_ofs,
 796         .write_begin = affs_write_begin_ofs,
 797         .write_end = affs_write_end_ofs
 798 };
 799
 800 /* Free any preallocated blocks. */
 801
 802 void
 803 affs_free_prealloc(struct inode *inode)
 804 {
 805         struct super_block *sb = inode->i_sb;
 806
 807         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 808
 809         while (AFFS_I(inode)->i_pa_cnt) {
 810                 AFFS_I(inode)->i_pa_cnt--;
 811                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 812         }
 813 }
 814
 815 /* Truncate (or enlarge) a file to the requested size. */
 816
 817 void
 818 affs_truncate(struct inode *inode)
 819 {
 820         struct super_block *sb = inode->i_sb;
 821         u32 ext, ext_key;
 822         u32 last_blk, blkcnt, blk;
 823         u32 size;
 824         struct buffer_head *ext_bh;
 825         int i;
 826
 827         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 828                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 829
 830         last_blk = 0;
 831         ext = 0;
 832         if (inode->i_size) {
 833                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 834                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 835         }
 836
 837         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 838                 struct address_space *mapping = inode->i_mapping;
 839                 struct page *page;
 840                 void *fsdata;
 841                 loff_t size = inode->i_size;
 842                 int res;
 843
 844                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 845                 if (!res)
 846                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 847                 else
 848                         inode->i_size = AFFS_I(inode)->mmu_private;
 849                 mark_inode_dirty(inode);
 850                 return;
 851         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 852                 return;
 853
 854         // lock cache
 855         ext_bh = affs_get_extblock(inode, ext);
 856         if (IS_ERR(ext_bh)) {
 857                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 858                              ext, PTR_ERR(ext_bh));
 859                 return;
 860         }
 861         if (AFFS_I(inode)->i_lc) {
 862                 /* clear linear cache */
 863                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 864                 if (AFFS_I(inode)->i_lc_size > i) {
 865                         AFFS_I(inode)->i_lc_size = i;
 866                         for (; i < AFFS_LC_SIZE; i++)
 867                                 AFFS_I(inode)->i_lc[i] = 0;
 868                 }
 869                 /* clear associative cache */
 870                 for (i = 0; i < AFFS_AC_SIZE; i++)
 871                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 872                                 AFFS_I(inode)->i_ac[i].ext = 0;
 873         }
 874         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 875
 876         blkcnt = AFFS_I(inode)->i_blkcnt;
 877         i = 0;
 878         blk = last_blk;
 879         if (inode->i_size) {
 880                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 881                 blk++;
 882         } else
 883                 AFFS_HEAD(ext_bh)->first_data = 0;
 884         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 885         size = AFFS_SB(sb)->s_hashsize;
 886         if (size > blkcnt - blk + i)
 887                 size = blkcnt - blk + i;
 888         for (; i < size; i++, blk++) {
 889                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 890                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 891         }
 892         AFFS_TAIL(sb, ext_bh)->extension = 0;
 893         affs_fix_checksum(sb, ext_bh);
 894         mark_buffer_dirty_inode(ext_bh, inode);
 895         affs_brelse(ext_bh);
 896
 897         if (inode->i_size) {
 898                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 899                 AFFS_I(inode)->i_extcnt = ext + 1;
 900                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 901                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 902                         u32 tmp;
 903                         if (IS_ERR(bh)) {
 904                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 905                                              ext, PTR_ERR(bh));
 906                                 return;
 907                         }
 908                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 909                         AFFS_DATA_HEAD(bh)->next = 0;
 910                         affs_adjust_checksum(bh, -tmp);
 911                         affs_brelse(bh);
 912                 }
 913         } else {
 914                 AFFS_I(inode)->i_blkcnt = 0;
 915                 AFFS_I(inode)->i_extcnt = 1;
 916         }
 917         AFFS_I(inode)->mmu_private = inode->i_size;
 918         // unlock cache
 919
 920         while (ext_key) {
 921                 ext_bh = affs_bread(sb, ext_key);
 922                 size = AFFS_SB(sb)->s_hashsize;
 923                 if (size > blkcnt - blk)
 924                         size = blkcnt - blk;
 925                 for (i = 0; i < size; i++, blk++)
 926                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 927                 affs_free_block(sb, ext_key);
 928                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 929                 affs_brelse(ext_bh);
 930         }
 931         affs_free_prealloc(inode);
 932 }
 933
 934 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 935 {
 936         struct inode *inode = filp->f_mapping->host;
 937         int ret, err;
 938
 939         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 940         if (err)
 941                 return err;
 942
 943         mutex_lock(&inode->i_mutex);
 944         ret = write_inode_now(inode, 0);
 945         err = sync_blockdev(inode->i_sb->s_bdev);
 946         if (!ret)
 947                 ret = err;
 948         mutex_unlock(&inode->i_mutex);
 949         return ret;
 950 }