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   1 /*
   2  *  linux/fs/affs/file.c
   3  *
   4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5  *
   6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7  *
   8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9  *
  10  *  (C) 1991  Linus Torvalds - minix filesystem
  11  *
  12  *  affs regular file handling primitives
  13  */
  14
  15 #include "affs.h"
  16
  17 #if PAGE_SIZE < 4096
  18 #error PAGE_SIZE must be at least 4096
  19 #endif
  20
  21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
  22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
  23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
  24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  25 static int affs_file_open(struct inode *inode, struct file *filp);
  26 static int affs_file_release(struct inode *inode, struct file *filp);
  27
  28 const struct file_operations affs_file_operations = {
  29         .llseek         = generic_file_llseek,
  30         .read           = do_sync_read,
  31         .aio_read       = generic_file_aio_read,
  32         .write          = do_sync_write,
  33         .aio_write      = generic_file_aio_write,
  34         .mmap           = generic_file_mmap,
  35         .open           = affs_file_open,
  36         .release        = affs_file_release,
  37         .fsync          = file_fsync,
  38         .splice_read    = generic_file_splice_read,
  39 };
  40
  41 const struct inode_operations affs_file_inode_operations = {
  42         .truncate       = affs_truncate,
  43         .setattr        = affs_notify_change,
  44 };
  45
  46 static int
  47 affs_file_open(struct inode *inode, struct file *filp)
  48 {
  49         if (atomic_read(&filp->f_count) != 1)
  50                 return 0;
  51         pr_debug("AFFS: open(%lu,%d)\n",
  52                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  53         atomic_inc(&AFFS_I(inode)->i_opencnt);
  54         return 0;
  55 }
  56
  57 static int
  58 affs_file_release(struct inode *inode, struct file *filp)
  59 {
  60         if (atomic_read(&filp->f_count) != 0)
  61                 return 0;
  62         pr_debug("AFFS: release(%lu, %d)\n",
  63                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  64
  65         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  66                 mutex_lock(&inode->i_mutex);
  67                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  68                         affs_truncate(inode);
  69                 affs_free_prealloc(inode);
  70                 mutex_unlock(&inode->i_mutex);
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int
  77 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  78 {
  79         struct super_block      *sb = inode->i_sb;
  80         struct buffer_head      *bh;
  81         u32 lc_max;
  82         int i, j, key;
  83
  84         if (!AFFS_I(inode)->i_lc) {
  85                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  86                 if (!ptr)
  87                         return -ENOMEM;
  88                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  89                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  90         }
  91
  92         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  93
  94         if (AFFS_I(inode)->i_extcnt > lc_max) {
  95                 u32 lc_shift, lc_mask, tmp, off;
  96
  97                 /* need to recalculate linear cache, start from old size */
  98                 lc_shift = AFFS_I(inode)->i_lc_shift;
  99                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
 100                 for (; tmp; tmp >>= 1)
 101                         lc_shift++;
 102                 lc_mask = (1 << lc_shift) - 1;
 103
 104                 /* fix idx and old size to new shift */
 105                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 106                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 107
 108                 /* first shrink old cache to make more space */
 109                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 110                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 111                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 112
 113                 AFFS_I(inode)->i_lc_shift = lc_shift;
 114                 AFFS_I(inode)->i_lc_mask = lc_mask;
 115         }
 116
 117         /* fill cache to the needed index */
 118         i = AFFS_I(inode)->i_lc_size;
 119         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 120         for (; i <= lc_idx; i++) {
 121                 if (!i) {
 122                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 123                         continue;
 124                 }
 125                 key = AFFS_I(inode)->i_lc[i - 1];
 126                 j = AFFS_I(inode)->i_lc_mask + 1;
 127                 // unlock cache
 128                 for (; j > 0; j--) {
 129                         bh = affs_bread(sb, key);
 130                         if (!bh)
 131                                 goto err;
 132                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 133                         affs_brelse(bh);
 134                 }
 135                 // lock cache
 136                 AFFS_I(inode)->i_lc[i] = key;
 137         }
 138
 139         return 0;
 140
 141 err:
 142         // lock cache
 143         return -EIO;
 144 }
 145
 146 static struct buffer_head *
 147 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 148 {
 149         struct super_block *sb = inode->i_sb;
 150         struct buffer_head *new_bh;
 151         u32 blocknr, tmp;
 152
 153         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 154         if (!blocknr)
 155                 return ERR_PTR(-ENOSPC);
 156
 157         new_bh = affs_getzeroblk(sb, blocknr);
 158         if (!new_bh) {
 159                 affs_free_block(sb, blocknr);
 160                 return ERR_PTR(-EIO);
 161         }
 162
 163         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 164         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 165         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 166         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 167         affs_fix_checksum(sb, new_bh);
 168
 169         mark_buffer_dirty_inode(new_bh, inode);
 170
 171         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 172         if (tmp)
 173                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 174         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 175         affs_adjust_checksum(bh, blocknr - tmp);
 176         mark_buffer_dirty_inode(bh, inode);
 177
 178         AFFS_I(inode)->i_extcnt++;
 179         mark_inode_dirty(inode);
 180
 181         return new_bh;
 182 }
 183
 184 static inline struct buffer_head *
 185 affs_get_extblock(struct inode *inode, u32 ext)
 186 {
 187         /* inline the simplest case: same extended block as last time */
 188         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 189         if (ext == AFFS_I(inode)->i_ext_last)
 190                 get_bh(bh);
 191         else
 192                 /* we have to do more (not inlined) */
 193                 bh = affs_get_extblock_slow(inode, ext);
 194
 195         return bh;
 196 }
 197
 198 static struct buffer_head *
 199 affs_get_extblock_slow(struct inode *inode, u32 ext)
 200 {
 201         struct super_block *sb = inode->i_sb;
 202         struct buffer_head *bh;
 203         u32 ext_key;
 204         u32 lc_idx, lc_off, ac_idx;
 205         u32 tmp, idx;
 206
 207         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 208                 /* read the next extended block from the current one */
 209                 bh = AFFS_I(inode)->i_ext_bh;
 210                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 211                 if (ext < AFFS_I(inode)->i_extcnt)
 212                         goto read_ext;
 213                 if (ext > AFFS_I(inode)->i_extcnt)
 214                         BUG();
 215                 bh = affs_alloc_extblock(inode, bh, ext);
 216                 if (IS_ERR(bh))
 217                         return bh;
 218                 goto store_ext;
 219         }
 220
 221         if (ext == 0) {
 222                 /* we seek back to the file header block */
 223                 ext_key = inode->i_ino;
 224                 goto read_ext;
 225         }
 226
 227         if (ext >= AFFS_I(inode)->i_extcnt) {
 228                 struct buffer_head *prev_bh;
 229
 230                 /* allocate a new extended block */
 231                 if (ext > AFFS_I(inode)->i_extcnt)
 232                         BUG();
 233
 234                 /* get previous extended block */
 235                 prev_bh = affs_get_extblock(inode, ext - 1);
 236                 if (IS_ERR(prev_bh))
 237                         return prev_bh;
 238                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 239                 affs_brelse(prev_bh);
 240                 if (IS_ERR(bh))
 241                         return bh;
 242                 goto store_ext;
 243         }
 244
 245 again:
 246         /* check if there is an extended cache and whether it's large enough */
 247         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 248         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 249
 250         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 251                 int err;
 252
 253                 err = affs_grow_extcache(inode, lc_idx);
 254                 if (err)
 255                         return ERR_PTR(err);
 256                 goto again;
 257         }
 258
 259         /* every n'th key we find in the linear cache */
 260         if (!lc_off) {
 261                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 262                 goto read_ext;
 263         }
 264
 265         /* maybe it's still in the associative cache */
 266         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 267         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 268                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 269                 goto read_ext;
 270         }
 271
 272         /* try to find one of the previous extended blocks */
 273         tmp = ext;
 274         idx = ac_idx;
 275         while (--tmp, --lc_off > 0) {
 276                 idx = (idx - 1) & AFFS_AC_MASK;
 277                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 278                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 279                         goto find_ext;
 280                 }
 281         }
 282
 283         /* fall back to the linear cache */
 284         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 285 find_ext:
 286         /* read all extended blocks until we find the one we need */
 287         //unlock cache
 288         do {
 289                 bh = affs_bread(sb, ext_key);
 290                 if (!bh)
 291                         goto err_bread;
 292                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 293                 affs_brelse(bh);
 294                 tmp++;
 295         } while (tmp < ext);
 296         //lock cache
 297
 298         /* store it in the associative cache */
 299         // recalculate ac_idx?
 300         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 301         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 302
 303 read_ext:
 304         /* finally read the right extended block */
 305         //unlock cache
 306         bh = affs_bread(sb, ext_key);
 307         if (!bh)
 308                 goto err_bread;
 309         //lock cache
 310
 311 store_ext:
 312         /* release old cached extended block and store the new one */
 313         affs_brelse(AFFS_I(inode)->i_ext_bh);
 314         AFFS_I(inode)->i_ext_last = ext;
 315         AFFS_I(inode)->i_ext_bh = bh;
 316         get_bh(bh);
 317
 318         return bh;
 319
 320 err_bread:
 321         affs_brelse(bh);
 322         return ERR_PTR(-EIO);
 323 }
 324
 325 static int
 326 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 327 {
 328         struct super_block      *sb = inode->i_sb;
 329         struct buffer_head      *ext_bh;
 330         u32                      ext;
 331
 332         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 333
 334         BUG_ON(block > (sector_t)0x7fffffffUL);
 335
 336         if (block >= AFFS_I(inode)->i_blkcnt) {
 337                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 338                         goto err_big;
 339         } else
 340                 create = 0;
 341
 342         //lock cache
 343         affs_lock_ext(inode);
 344
 345         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 346         block -= ext * AFFS_SB(sb)->s_hashsize;
 347         ext_bh = affs_get_extblock(inode, ext);
 348         if (IS_ERR(ext_bh))
 349                 goto err_ext;
 350         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 351
 352         if (create) {
 353                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 354                 if (!blocknr)
 355                         goto err_alloc;
 356                 set_buffer_new(bh_result);
 357                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 358                 AFFS_I(inode)->i_blkcnt++;
 359
 360                 /* store new block */
 361                 if (bh_result->b_blocknr)
 362                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
 363                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 364                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 365                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 366                 bh_result->b_blocknr = blocknr;
 367
 368                 if (!block) {
 369                         /* insert first block into header block */
 370                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 371                         if (tmp)
 372                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 373                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 374                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 375                 }
 376         }
 377
 378         affs_brelse(ext_bh);
 379         //unlock cache
 380         affs_unlock_ext(inode);
 381         return 0;
 382
 383 err_big:
 384         affs_error(inode->i_sb,"get_block","strange block request %d", block);
 385         return -EIO;
 386 err_ext:
 387         // unlock cache
 388         affs_unlock_ext(inode);
 389         return PTR_ERR(ext_bh);
 390 err_alloc:
 391         brelse(ext_bh);
 392         clear_buffer_mapped(bh_result);
 393         bh_result->b_bdev = NULL;
 394         // unlock cache
 395         affs_unlock_ext(inode);
 396         return -ENOSPC;
 397 }
 398
 399 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 400 {
 401         return block_write_full_page(page, affs_get_block, wbc);
 402 }
 403
 404 static int affs_readpage(struct file *file, struct page *page)
 405 {
 406         return block_read_full_page(page, affs_get_block);
 407 }
 408
 409 static int affs_write_begin(struct file *file, struct address_space *mapping,
 410                         loff_t pos, unsigned len, unsigned flags,
 411                         struct page **pagep, void **fsdata)
 412 {
 413         *pagep = NULL;
 414         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 415                                 affs_get_block,
 416                                 &AFFS_I(mapping->host)->mmu_private);
 417 }
 418
 419 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 420 {
 421         return generic_block_bmap(mapping,block,affs_get_block);
 422 }
 423
 424 const struct address_space_operations affs_aops = {
 425         .readpage = affs_readpage,
 426         .writepage = affs_writepage,
 427         .sync_page = block_sync_page,
 428         .write_begin = affs_write_begin,
 429         .write_end = generic_write_end,
 430         .bmap = _affs_bmap
 431 };
 432
 433 static inline struct buffer_head *
 434 affs_bread_ino(struct inode *inode, int block, int create)
 435 {
 436         struct buffer_head *bh, tmp_bh;
 437         int err;
 438
 439         tmp_bh.b_state = 0;
 440         err = affs_get_block(inode, block, &tmp_bh, create);
 441         if (!err) {
 442                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 443                 if (bh) {
 444                         bh->b_state |= tmp_bh.b_state;
 445                         return bh;
 446                 }
 447                 err = -EIO;
 448         }
 449         return ERR_PTR(err);
 450 }
 451
 452 static inline struct buffer_head *
 453 affs_getzeroblk_ino(struct inode *inode, int block)
 454 {
 455         struct buffer_head *bh, tmp_bh;
 456         int err;
 457
 458         tmp_bh.b_state = 0;
 459         err = affs_get_block(inode, block, &tmp_bh, 1);
 460         if (!err) {
 461                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 462                 if (bh) {
 463                         bh->b_state |= tmp_bh.b_state;
 464                         return bh;
 465                 }
 466                 err = -EIO;
 467         }
 468         return ERR_PTR(err);
 469 }
 470
 471 static inline struct buffer_head *
 472 affs_getemptyblk_ino(struct inode *inode, int block)
 473 {
 474         struct buffer_head *bh, tmp_bh;
 475         int err;
 476
 477         tmp_bh.b_state = 0;
 478         err = affs_get_block(inode, block, &tmp_bh, 1);
 479         if (!err) {
 480                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 481                 if (bh) {
 482                         bh->b_state |= tmp_bh.b_state;
 483                         return bh;
 484                 }
 485                 err = -EIO;
 486         }
 487         return ERR_PTR(err);
 488 }
 489
 490 static int
 491 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 492 {
 493         struct inode *inode = page->mapping->host;
 494         struct super_block *sb = inode->i_sb;
 495         struct buffer_head *bh;
 496         char *data;
 497         u32 bidx, boff, bsize;
 498         u32 tmp;
 499
 500         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 501         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
 502         kmap(page);
 503         data = page_address(page);
 504         bsize = AFFS_SB(sb)->s_data_blksize;
 505         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 506         bidx = tmp / bsize;
 507         boff = tmp % bsize;
 508
 509         while (from < to) {
 510                 bh = affs_bread_ino(inode, bidx, 0);
 511                 if (IS_ERR(bh))
 512                         return PTR_ERR(bh);
 513                 tmp = min(bsize - boff, to - from);
 514                 BUG_ON(from + tmp > to || tmp > bsize);
 515                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 516                 affs_brelse(bh);
 517                 bidx++;
 518                 from += tmp;
 519                 boff = 0;
 520         }
 521         flush_dcache_page(page);
 522         kunmap(page);
 523         return 0;
 524 }
 525
 526 static int
 527 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 528 {
 529         struct super_block *sb = inode->i_sb;
 530         struct buffer_head *bh, *prev_bh;
 531         u32 bidx, boff;
 532         u32 size, bsize;
 533         u32 tmp;
 534
 535         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 536         bsize = AFFS_SB(sb)->s_data_blksize;
 537         bh = NULL;
 538         size = AFFS_I(inode)->mmu_private;
 539         bidx = size / bsize;
 540         boff = size % bsize;
 541         if (boff) {
 542                 bh = affs_bread_ino(inode, bidx, 0);
 543                 if (IS_ERR(bh))
 544                         return PTR_ERR(bh);
 545                 tmp = min(bsize - boff, newsize - size);
 546                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 547                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 548                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 549                 affs_fix_checksum(sb, bh);
 550                 mark_buffer_dirty_inode(bh, inode);
 551                 size += tmp;
 552                 bidx++;
 553         } else if (bidx) {
 554                 bh = affs_bread_ino(inode, bidx - 1, 0);
 555                 if (IS_ERR(bh))
 556                         return PTR_ERR(bh);
 557         }
 558
 559         while (size < newsize) {
 560                 prev_bh = bh;
 561                 bh = affs_getzeroblk_ino(inode, bidx);
 562                 if (IS_ERR(bh))
 563                         goto out;
 564                 tmp = min(bsize, newsize - size);
 565                 BUG_ON(tmp > bsize);
 566                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 567                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 568                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 569                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 570                 affs_fix_checksum(sb, bh);
 571                 bh->b_state &= ~(1UL << BH_New);
 572                 mark_buffer_dirty_inode(bh, inode);
 573                 if (prev_bh) {
 574                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 575                         if (tmp)
 576                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 577                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 578                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 579                         mark_buffer_dirty_inode(prev_bh, inode);
 580                         affs_brelse(prev_bh);
 581                 }
 582                 size += bsize;
 583                 bidx++;
 584         }
 585         affs_brelse(bh);
 586         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 587         return 0;
 588
 589 out:
 590         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 591         return PTR_ERR(bh);
 592 }
 593
 594 static int
 595 affs_readpage_ofs(struct file *file, struct page *page)
 596 {
 597         struct inode *inode = page->mapping->host;
 598         u32 to;
 599         int err;
 600
 601         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 602         to = PAGE_CACHE_SIZE;
 603         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 604                 to = inode->i_size & ~PAGE_CACHE_MASK;
 605                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 606         }
 607
 608         err = affs_do_readpage_ofs(file, page, 0, to);
 609         if (!err)
 610                 SetPageUptodate(page);
 611         unlock_page(page);
 612         return err;
 613 }
 614
 615 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 616                                 loff_t pos, unsigned len, unsigned flags,
 617                                 struct page **pagep, void **fsdata)
 618 {
 619         struct inode *inode = mapping->host;
 620         struct page *page;
 621         pgoff_t index;
 622         int err = 0;
 623
 624         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 625         if (pos > AFFS_I(inode)->mmu_private) {
 626                 /* XXX: this probably leaves a too-big i_size in case of
 627                  * failure. Should really be updating i_size at write_end time
 628                  */
 629                 err = affs_extent_file_ofs(inode, pos);
 630                 if (err)
 631                         return err;
 632         }
 633
 634         index = pos >> PAGE_CACHE_SHIFT;
 635         page = __grab_cache_page(mapping, index);
 636         if (!page)
 637                 return -ENOMEM;
 638         *pagep = page;
 639
 640         if (PageUptodate(page))
 641                 return 0;
 642
 643         /* XXX: inefficient but safe in the face of short writes */
 644         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
 645         if (err) {
 646                 unlock_page(page);
 647                 page_cache_release(page);
 648         }
 649         return err;
 650 }
 651
 652 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 653                                 loff_t pos, unsigned len, unsigned copied,
 654                                 struct page *page, void *fsdata)
 655 {
 656         struct inode *inode = mapping->host;
 657         struct super_block *sb = inode->i_sb;
 658         struct buffer_head *bh, *prev_bh;
 659         char *data;
 660         u32 bidx, boff, bsize;
 661         unsigned from, to;
 662         u32 tmp;
 663         int written;
 664
 665         from = pos & (PAGE_CACHE_SIZE - 1);
 666         to = pos + len;
 667         /*
 668          * XXX: not sure if this can handle short copies (len < copied), but
 669          * we don't have to, because the page should always be uptodate here,
 670          * due to write_begin.
 671          */
 672
 673         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 674         bsize = AFFS_SB(sb)->s_data_blksize;
 675         data = page_address(page);
 676
 677         bh = NULL;
 678         written = 0;
 679         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 680         bidx = tmp / bsize;
 681         boff = tmp % bsize;
 682         if (boff) {
 683                 bh = affs_bread_ino(inode, bidx, 0);
 684                 if (IS_ERR(bh))
 685                         return PTR_ERR(bh);
 686                 tmp = min(bsize - boff, to - from);
 687                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 688                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 689                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 690                 affs_fix_checksum(sb, bh);
 691                 mark_buffer_dirty_inode(bh, inode);
 692                 written += tmp;
 693                 from += tmp;
 694                 bidx++;
 695         } else if (bidx) {
 696                 bh = affs_bread_ino(inode, bidx - 1, 0);
 697                 if (IS_ERR(bh))
 698                         return PTR_ERR(bh);
 699         }
 700         while (from + bsize <= to) {
 701                 prev_bh = bh;
 702                 bh = affs_getemptyblk_ino(inode, bidx);
 703                 if (IS_ERR(bh))
 704                         goto out;
 705                 memcpy(AFFS_DATA(bh), data + from, bsize);
 706                 if (buffer_new(bh)) {
 707                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 708                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 709                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 710                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 711                         AFFS_DATA_HEAD(bh)->next = 0;
 712                         bh->b_state &= ~(1UL << BH_New);
 713                         if (prev_bh) {
 714                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 715                                 if (tmp)
 716                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 717                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 718                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 719                                 mark_buffer_dirty_inode(prev_bh, inode);
 720                         }
 721                 }
 722                 affs_brelse(prev_bh);
 723                 affs_fix_checksum(sb, bh);
 724                 mark_buffer_dirty_inode(bh, inode);
 725                 written += bsize;
 726                 from += bsize;
 727                 bidx++;
 728         }
 729         if (from < to) {
 730                 prev_bh = bh;
 731                 bh = affs_bread_ino(inode, bidx, 1);
 732                 if (IS_ERR(bh))
 733                         goto out;
 734                 tmp = min(bsize, to - from);
 735                 BUG_ON(tmp > bsize);
 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         unlock_page(page);
 770         page_cache_release(page);
 771
 772         return written;
 773
 774 out:
 775         bh = prev_bh;
 776         if (!written)
 777                 written = PTR_ERR(bh);
 778         goto done;
 779 }
 780
 781 const struct address_space_operations affs_aops_ofs = {
 782         .readpage = affs_readpage_ofs,
 783         //.writepage = affs_writepage_ofs,
 784         //.sync_page = affs_sync_page_ofs,
 785         .write_begin = affs_write_begin_ofs,
 786         .write_end = affs_write_end_ofs
 787 };
 788
 789 /* Free any preallocated blocks. */
 790
 791 void
 792 affs_free_prealloc(struct inode *inode)
 793 {
 794         struct super_block *sb = inode->i_sb;
 795
 796         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 797
 798         while (AFFS_I(inode)->i_pa_cnt) {
 799                 AFFS_I(inode)->i_pa_cnt--;
 800                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 801         }
 802 }
 803
 804 /* Truncate (or enlarge) a file to the requested size. */
 805
 806 void
 807 affs_truncate(struct inode *inode)
 808 {
 809         struct super_block *sb = inode->i_sb;
 810         u32 ext, ext_key;
 811         u32 last_blk, blkcnt, blk;
 812         u32 size;
 813         struct buffer_head *ext_bh;
 814         int i;
 815
 816         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 817                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 818
 819         last_blk = 0;
 820         ext = 0;
 821         if (inode->i_size) {
 822                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 823                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 824         }
 825
 826         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 827                 struct address_space *mapping = inode->i_mapping;
 828                 struct page *page;
 829                 void *fsdata;
 830                 u32 size = inode->i_size;
 831                 int res;
 832
 833                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 834                 if (!res)
 835                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 836                 else
 837                         inode->i_size = AFFS_I(inode)->mmu_private;
 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         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 874         size = AFFS_SB(sb)->s_hashsize;
 875         if (size > blkcnt - blk + i)
 876                 size = blkcnt - blk + i;
 877         for (; i < size; i++, blk++) {
 878                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 879                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 880         }
 881         AFFS_TAIL(sb, ext_bh)->extension = 0;
 882         affs_fix_checksum(sb, ext_bh);
 883         mark_buffer_dirty_inode(ext_bh, inode);
 884         affs_brelse(ext_bh);
 885
 886         if (inode->i_size) {
 887                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 888                 AFFS_I(inode)->i_extcnt = ext + 1;
 889                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 890                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 891                         u32 tmp;
 892                         if (IS_ERR(ext_bh)) {
 893                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 894                                              ext, PTR_ERR(ext_bh));
 895                                 return;
 896                         }
 897                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 898                         AFFS_DATA_HEAD(bh)->next = 0;
 899                         affs_adjust_checksum(bh, -tmp);
 900                         affs_brelse(bh);
 901                 }
 902         } else {
 903                 AFFS_I(inode)->i_blkcnt = 0;
 904                 AFFS_I(inode)->i_extcnt = 1;
 905         }
 906         AFFS_I(inode)->mmu_private = inode->i_size;
 907         // unlock cache
 908
 909         while (ext_key) {
 910                 ext_bh = affs_bread(sb, ext_key);
 911                 size = AFFS_SB(sb)->s_hashsize;
 912                 if (size > blkcnt - blk)
 913                         size = blkcnt - blk;
 914                 for (i = 0; i < size; i++, blk++)
 915                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 916                 affs_free_block(sb, ext_key);
 917                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 918                 affs_brelse(ext_bh);
 919         }
 920         affs_free_prealloc(inode);
 921 }