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          = 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         pr_debug("AFFS: open(%lu,%d)\n",
  50                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  51         atomic_inc(&AFFS_I(inode)->i_opencnt);
  52         return 0;
  53 }
  54
  55 static int
  56 affs_file_release(struct inode *inode, struct file *filp)
  57 {
  58         pr_debug("AFFS: release(%lu, %d)\n",
  59                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  60
  61         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  62                 mutex_lock(&inode->i_mutex);
  63                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  64                         affs_truncate(inode);
  65                 affs_free_prealloc(inode);
  66                 mutex_unlock(&inode->i_mutex);
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int
  73 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  74 {
  75         struct super_block      *sb = inode->i_sb;
  76         struct buffer_head      *bh;
  77         u32 lc_max;
  78         int i, j, key;
  79
  80         if (!AFFS_I(inode)->i_lc) {
  81                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  82                 if (!ptr)
  83                         return -ENOMEM;
  84                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  85                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  86         }
  87
  88         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  89
  90         if (AFFS_I(inode)->i_extcnt > lc_max) {
  91                 u32 lc_shift, lc_mask, tmp, off;
  92
  93                 /* need to recalculate linear cache, start from old size */
  94                 lc_shift = AFFS_I(inode)->i_lc_shift;
  95                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  96                 for (; tmp; tmp >>= 1)
  97                         lc_shift++;
  98                 lc_mask = (1 << lc_shift) - 1;
  99
 100                 /* fix idx and old size to new shift */
 101                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 102                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 103
 104                 /* first shrink old cache to make more space */
 105                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 106                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 107                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 108
 109                 AFFS_I(inode)->i_lc_shift = lc_shift;
 110                 AFFS_I(inode)->i_lc_mask = lc_mask;
 111         }
 112
 113         /* fill cache to the needed index */
 114         i = AFFS_I(inode)->i_lc_size;
 115         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 116         for (; i <= lc_idx; i++) {
 117                 if (!i) {
 118                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 119                         continue;
 120                 }
 121                 key = AFFS_I(inode)->i_lc[i - 1];
 122                 j = AFFS_I(inode)->i_lc_mask + 1;
 123                 // unlock cache
 124                 for (; j > 0; j--) {
 125                         bh = affs_bread(sb, key);
 126                         if (!bh)
 127                                 goto err;
 128                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 129                         affs_brelse(bh);
 130                 }
 131                 // lock cache
 132                 AFFS_I(inode)->i_lc[i] = key;
 133         }
 134
 135         return 0;
 136
 137 err:
 138         // lock cache
 139         return -EIO;
 140 }
 141
 142 static struct buffer_head *
 143 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 144 {
 145         struct super_block *sb = inode->i_sb;
 146         struct buffer_head *new_bh;
 147         u32 blocknr, tmp;
 148
 149         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 150         if (!blocknr)
 151                 return ERR_PTR(-ENOSPC);
 152
 153         new_bh = affs_getzeroblk(sb, blocknr);
 154         if (!new_bh) {
 155                 affs_free_block(sb, blocknr);
 156                 return ERR_PTR(-EIO);
 157         }
 158
 159         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 160         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 161         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 162         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 163         affs_fix_checksum(sb, new_bh);
 164
 165         mark_buffer_dirty_inode(new_bh, inode);
 166
 167         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 168         if (tmp)
 169                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 170         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 171         affs_adjust_checksum(bh, blocknr - tmp);
 172         mark_buffer_dirty_inode(bh, inode);
 173
 174         AFFS_I(inode)->i_extcnt++;
 175         mark_inode_dirty(inode);
 176
 177         return new_bh;
 178 }
 179
 180 static inline struct buffer_head *
 181 affs_get_extblock(struct inode *inode, u32 ext)
 182 {
 183         /* inline the simplest case: same extended block as last time */
 184         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 185         if (ext == AFFS_I(inode)->i_ext_last)
 186                 get_bh(bh);
 187         else
 188                 /* we have to do more (not inlined) */
 189                 bh = affs_get_extblock_slow(inode, ext);
 190
 191         return bh;
 192 }
 193
 194 static struct buffer_head *
 195 affs_get_extblock_slow(struct inode *inode, u32 ext)
 196 {
 197         struct super_block *sb = inode->i_sb;
 198         struct buffer_head *bh;
 199         u32 ext_key;
 200         u32 lc_idx, lc_off, ac_idx;
 201         u32 tmp, idx;
 202
 203         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 204                 /* read the next extended block from the current one */
 205                 bh = AFFS_I(inode)->i_ext_bh;
 206                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 207                 if (ext < AFFS_I(inode)->i_extcnt)
 208                         goto read_ext;
 209                 if (ext > AFFS_I(inode)->i_extcnt)
 210                         BUG();
 211                 bh = affs_alloc_extblock(inode, bh, ext);
 212                 if (IS_ERR(bh))
 213                         return bh;
 214                 goto store_ext;
 215         }
 216
 217         if (ext == 0) {
 218                 /* we seek back to the file header block */
 219                 ext_key = inode->i_ino;
 220                 goto read_ext;
 221         }
 222
 223         if (ext >= AFFS_I(inode)->i_extcnt) {
 224                 struct buffer_head *prev_bh;
 225
 226                 /* allocate a new extended block */
 227                 if (ext > AFFS_I(inode)->i_extcnt)
 228                         BUG();
 229
 230                 /* get previous extended block */
 231                 prev_bh = affs_get_extblock(inode, ext - 1);
 232                 if (IS_ERR(prev_bh))
 233                         return prev_bh;
 234                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 235                 affs_brelse(prev_bh);
 236                 if (IS_ERR(bh))
 237                         return bh;
 238                 goto store_ext;
 239         }
 240
 241 again:
 242         /* check if there is an extended cache and whether it's large enough */
 243         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 244         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 245
 246         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 247                 int err;
 248
 249                 err = affs_grow_extcache(inode, lc_idx);
 250                 if (err)
 251                         return ERR_PTR(err);
 252                 goto again;
 253         }
 254
 255         /* every n'th key we find in the linear cache */
 256         if (!lc_off) {
 257                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 258                 goto read_ext;
 259         }
 260
 261         /* maybe it's still in the associative cache */
 262         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 263         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 264                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 265                 goto read_ext;
 266         }
 267
 268         /* try to find one of the previous extended blocks */
 269         tmp = ext;
 270         idx = ac_idx;
 271         while (--tmp, --lc_off > 0) {
 272                 idx = (idx - 1) & AFFS_AC_MASK;
 273                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 274                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 275                         goto find_ext;
 276                 }
 277         }
 278
 279         /* fall back to the linear cache */
 280         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 281 find_ext:
 282         /* read all extended blocks until we find the one we need */
 283         //unlock cache
 284         do {
 285                 bh = affs_bread(sb, ext_key);
 286                 if (!bh)
 287                         goto err_bread;
 288                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 289                 affs_brelse(bh);
 290                 tmp++;
 291         } while (tmp < ext);
 292         //lock cache
 293
 294         /* store it in the associative cache */
 295         // recalculate ac_idx?
 296         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 297         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 298
 299 read_ext:
 300         /* finally read the right extended block */
 301         //unlock cache
 302         bh = affs_bread(sb, ext_key);
 303         if (!bh)
 304                 goto err_bread;
 305         //lock cache
 306
 307 store_ext:
 308         /* release old cached extended block and store the new one */
 309         affs_brelse(AFFS_I(inode)->i_ext_bh);
 310         AFFS_I(inode)->i_ext_last = ext;
 311         AFFS_I(inode)->i_ext_bh = bh;
 312         get_bh(bh);
 313
 314         return bh;
 315
 316 err_bread:
 317         affs_brelse(bh);
 318         return ERR_PTR(-EIO);
 319 }
 320
 321 static int
 322 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 323 {
 324         struct super_block      *sb = inode->i_sb;
 325         struct buffer_head      *ext_bh;
 326         u32                      ext;
 327
 328         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 329
 330         BUG_ON(block > (sector_t)0x7fffffffUL);
 331
 332         if (block >= AFFS_I(inode)->i_blkcnt) {
 333                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 334                         goto err_big;
 335         } else
 336                 create = 0;
 337
 338         //lock cache
 339         affs_lock_ext(inode);
 340
 341         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 342         block -= ext * AFFS_SB(sb)->s_hashsize;
 343         ext_bh = affs_get_extblock(inode, ext);
 344         if (IS_ERR(ext_bh))
 345                 goto err_ext;
 346         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 347
 348         if (create) {
 349                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 350                 if (!blocknr)
 351                         goto err_alloc;
 352                 set_buffer_new(bh_result);
 353                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 354                 AFFS_I(inode)->i_blkcnt++;
 355
 356                 /* store new block */
 357                 if (bh_result->b_blocknr)
 358                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
 359                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 360                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 361                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 362                 bh_result->b_blocknr = blocknr;
 363
 364                 if (!block) {
 365                         /* insert first block into header block */
 366                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 367                         if (tmp)
 368                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 369                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 370                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 371                 }
 372         }
 373
 374         affs_brelse(ext_bh);
 375         //unlock cache
 376         affs_unlock_ext(inode);
 377         return 0;
 378
 379 err_big:
 380         affs_error(inode->i_sb,"get_block","strange block request %d", block);
 381         return -EIO;
 382 err_ext:
 383         // unlock cache
 384         affs_unlock_ext(inode);
 385         return PTR_ERR(ext_bh);
 386 err_alloc:
 387         brelse(ext_bh);
 388         clear_buffer_mapped(bh_result);
 389         bh_result->b_bdev = NULL;
 390         // unlock cache
 391         affs_unlock_ext(inode);
 392         return -ENOSPC;
 393 }
 394
 395 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 396 {
 397         return block_write_full_page(page, affs_get_block, wbc);
 398 }
 399
 400 static int affs_readpage(struct file *file, struct page *page)
 401 {
 402         return block_read_full_page(page, affs_get_block);
 403 }
 404
 405 static int affs_write_begin(struct file *file, struct address_space *mapping,
 406                         loff_t pos, unsigned len, unsigned flags,
 407                         struct page **pagep, void **fsdata)
 408 {
 409         *pagep = NULL;
 410         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 411                                 affs_get_block,
 412                                 &AFFS_I(mapping->host)->mmu_private);
 413 }
 414
 415 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 416 {
 417         return generic_block_bmap(mapping,block,affs_get_block);
 418 }
 419
 420 const struct address_space_operations affs_aops = {
 421         .readpage = affs_readpage,
 422         .writepage = affs_writepage,
 423         .sync_page = block_sync_page,
 424         .write_begin = affs_write_begin,
 425         .write_end = generic_write_end,
 426         .bmap = _affs_bmap
 427 };
 428
 429 static inline struct buffer_head *
 430 affs_bread_ino(struct inode *inode, int block, int create)
 431 {
 432         struct buffer_head *bh, tmp_bh;
 433         int err;
 434
 435         tmp_bh.b_state = 0;
 436         err = affs_get_block(inode, block, &tmp_bh, create);
 437         if (!err) {
 438                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 439                 if (bh) {
 440                         bh->b_state |= tmp_bh.b_state;
 441                         return bh;
 442                 }
 443                 err = -EIO;
 444         }
 445         return ERR_PTR(err);
 446 }
 447
 448 static inline struct buffer_head *
 449 affs_getzeroblk_ino(struct inode *inode, int block)
 450 {
 451         struct buffer_head *bh, tmp_bh;
 452         int err;
 453
 454         tmp_bh.b_state = 0;
 455         err = affs_get_block(inode, block, &tmp_bh, 1);
 456         if (!err) {
 457                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 458                 if (bh) {
 459                         bh->b_state |= tmp_bh.b_state;
 460                         return bh;
 461                 }
 462                 err = -EIO;
 463         }
 464         return ERR_PTR(err);
 465 }
 466
 467 static inline struct buffer_head *
 468 affs_getemptyblk_ino(struct inode *inode, int block)
 469 {
 470         struct buffer_head *bh, tmp_bh;
 471         int err;
 472
 473         tmp_bh.b_state = 0;
 474         err = affs_get_block(inode, block, &tmp_bh, 1);
 475         if (!err) {
 476                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 477                 if (bh) {
 478                         bh->b_state |= tmp_bh.b_state;
 479                         return bh;
 480                 }
 481                 err = -EIO;
 482         }
 483         return ERR_PTR(err);
 484 }
 485
 486 static int
 487 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 488 {
 489         struct inode *inode = page->mapping->host;
 490         struct super_block *sb = inode->i_sb;
 491         struct buffer_head *bh;
 492         char *data;
 493         u32 bidx, boff, bsize;
 494         u32 tmp;
 495
 496         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 497         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
 498         kmap(page);
 499         data = page_address(page);
 500         bsize = AFFS_SB(sb)->s_data_blksize;
 501         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 502         bidx = tmp / bsize;
 503         boff = tmp % bsize;
 504
 505         while (from < to) {
 506                 bh = affs_bread_ino(inode, bidx, 0);
 507                 if (IS_ERR(bh))
 508                         return PTR_ERR(bh);
 509                 tmp = min(bsize - boff, to - from);
 510                 BUG_ON(from + tmp > to || tmp > bsize);
 511                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 512                 affs_brelse(bh);
 513                 bidx++;
 514                 from += tmp;
 515                 boff = 0;
 516         }
 517         flush_dcache_page(page);
 518         kunmap(page);
 519         return 0;
 520 }
 521
 522 static int
 523 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 524 {
 525         struct super_block *sb = inode->i_sb;
 526         struct buffer_head *bh, *prev_bh;
 527         u32 bidx, boff;
 528         u32 size, bsize;
 529         u32 tmp;
 530
 531         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 532         bsize = AFFS_SB(sb)->s_data_blksize;
 533         bh = NULL;
 534         size = AFFS_I(inode)->mmu_private;
 535         bidx = size / bsize;
 536         boff = size % bsize;
 537         if (boff) {
 538                 bh = affs_bread_ino(inode, bidx, 0);
 539                 if (IS_ERR(bh))
 540                         return PTR_ERR(bh);
 541                 tmp = min(bsize - boff, newsize - size);
 542                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 543                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 544                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 545                 affs_fix_checksum(sb, bh);
 546                 mark_buffer_dirty_inode(bh, inode);
 547                 size += tmp;
 548                 bidx++;
 549         } else if (bidx) {
 550                 bh = affs_bread_ino(inode, bidx - 1, 0);
 551                 if (IS_ERR(bh))
 552                         return PTR_ERR(bh);
 553         }
 554
 555         while (size < newsize) {
 556                 prev_bh = bh;
 557                 bh = affs_getzeroblk_ino(inode, bidx);
 558                 if (IS_ERR(bh))
 559                         goto out;
 560                 tmp = min(bsize, newsize - size);
 561                 BUG_ON(tmp > bsize);
 562                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 563                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 564                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 565                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 566                 affs_fix_checksum(sb, bh);
 567                 bh->b_state &= ~(1UL << BH_New);
 568                 mark_buffer_dirty_inode(bh, inode);
 569                 if (prev_bh) {
 570                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 571                         if (tmp)
 572                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 573                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 574                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 575                         mark_buffer_dirty_inode(prev_bh, inode);
 576                         affs_brelse(prev_bh);
 577                 }
 578                 size += bsize;
 579                 bidx++;
 580         }
 581         affs_brelse(bh);
 582         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 583         return 0;
 584
 585 out:
 586         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 587         return PTR_ERR(bh);
 588 }
 589
 590 static int
 591 affs_readpage_ofs(struct file *file, struct page *page)
 592 {
 593         struct inode *inode = page->mapping->host;
 594         u32 to;
 595         int err;
 596
 597         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 598         to = PAGE_CACHE_SIZE;
 599         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 600                 to = inode->i_size & ~PAGE_CACHE_MASK;
 601                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 602         }
 603
 604         err = affs_do_readpage_ofs(file, page, 0, to);
 605         if (!err)
 606                 SetPageUptodate(page);
 607         unlock_page(page);
 608         return err;
 609 }
 610
 611 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 612                                 loff_t pos, unsigned len, unsigned flags,
 613                                 struct page **pagep, void **fsdata)
 614 {
 615         struct inode *inode = mapping->host;
 616         struct page *page;
 617         pgoff_t index;
 618         int err = 0;
 619
 620         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 621         if (pos > AFFS_I(inode)->mmu_private) {
 622                 /* XXX: this probably leaves a too-big i_size in case of
 623                  * failure. Should really be updating i_size at write_end time
 624                  */
 625                 err = affs_extent_file_ofs(inode, pos);
 626                 if (err)
 627                         return err;
 628         }
 629
 630         index = pos >> PAGE_CACHE_SHIFT;
 631         page = __grab_cache_page(mapping, index);
 632         if (!page)
 633                 return -ENOMEM;
 634         *pagep = page;
 635
 636         if (PageUptodate(page))
 637                 return 0;
 638
 639         /* XXX: inefficient but safe in the face of short writes */
 640         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
 641         if (err) {
 642                 unlock_page(page);
 643                 page_cache_release(page);
 644         }
 645         return err;
 646 }
 647
 648 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 649                                 loff_t pos, unsigned len, unsigned copied,
 650                                 struct page *page, void *fsdata)
 651 {
 652         struct inode *inode = mapping->host;
 653         struct super_block *sb = inode->i_sb;
 654         struct buffer_head *bh, *prev_bh;
 655         char *data;
 656         u32 bidx, boff, bsize;
 657         unsigned from, to;
 658         u32 tmp;
 659         int written;
 660
 661         from = pos & (PAGE_CACHE_SIZE - 1);
 662         to = pos + len;
 663         /*
 664          * XXX: not sure if this can handle short copies (len < copied), but
 665          * we don't have to, because the page should always be uptodate here,
 666          * due to write_begin.
 667          */
 668
 669         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 670         bsize = AFFS_SB(sb)->s_data_blksize;
 671         data = page_address(page);
 672
 673         bh = NULL;
 674         written = 0;
 675         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 676         bidx = tmp / bsize;
 677         boff = tmp % bsize;
 678         if (boff) {
 679                 bh = affs_bread_ino(inode, bidx, 0);
 680                 if (IS_ERR(bh))
 681                         return PTR_ERR(bh);
 682                 tmp = min(bsize - boff, to - from);
 683                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 684                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 685                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 686                 affs_fix_checksum(sb, bh);
 687                 mark_buffer_dirty_inode(bh, inode);
 688                 written += tmp;
 689                 from += tmp;
 690                 bidx++;
 691         } else if (bidx) {
 692                 bh = affs_bread_ino(inode, bidx - 1, 0);
 693                 if (IS_ERR(bh))
 694                         return PTR_ERR(bh);
 695         }
 696         while (from + bsize <= to) {
 697                 prev_bh = bh;
 698                 bh = affs_getemptyblk_ino(inode, bidx);
 699                 if (IS_ERR(bh))
 700                         goto out;
 701                 memcpy(AFFS_DATA(bh), data + from, bsize);
 702                 if (buffer_new(bh)) {
 703                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 704                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 705                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 706                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 707                         AFFS_DATA_HEAD(bh)->next = 0;
 708                         bh->b_state &= ~(1UL << BH_New);
 709                         if (prev_bh) {
 710                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 711                                 if (tmp)
 712                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 713                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 714                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 715                                 mark_buffer_dirty_inode(prev_bh, inode);
 716                         }
 717                 }
 718                 affs_brelse(prev_bh);
 719                 affs_fix_checksum(sb, bh);
 720                 mark_buffer_dirty_inode(bh, inode);
 721                 written += bsize;
 722                 from += bsize;
 723                 bidx++;
 724         }
 725         if (from < to) {
 726                 prev_bh = bh;
 727                 bh = affs_bread_ino(inode, bidx, 1);
 728                 if (IS_ERR(bh))
 729                         goto out;
 730                 tmp = min(bsize, to - from);
 731                 BUG_ON(tmp > bsize);
 732                 memcpy(AFFS_DATA(bh), data + from, tmp);
 733                 if (buffer_new(bh)) {
 734                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 735                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 736                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 737                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 738                         AFFS_DATA_HEAD(bh)->next = 0;
 739                         bh->b_state &= ~(1UL << BH_New);
 740                         if (prev_bh) {
 741                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 742                                 if (tmp)
 743                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 744                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 745                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 746                                 mark_buffer_dirty_inode(prev_bh, inode);
 747                         }
 748                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 749                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 750                 affs_brelse(prev_bh);
 751                 affs_fix_checksum(sb, bh);
 752                 mark_buffer_dirty_inode(bh, inode);
 753                 written += tmp;
 754                 from += tmp;
 755                 bidx++;
 756         }
 757         SetPageUptodate(page);
 758
 759 done:
 760         affs_brelse(bh);
 761         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 762         if (tmp > inode->i_size)
 763                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 764
 765         unlock_page(page);
 766         page_cache_release(page);
 767
 768         return written;
 769
 770 out:
 771         bh = prev_bh;
 772         if (!written)
 773                 written = PTR_ERR(bh);
 774         goto done;
 775 }
 776
 777 const struct address_space_operations affs_aops_ofs = {
 778         .readpage = affs_readpage_ofs,
 779         //.writepage = affs_writepage_ofs,
 780         //.sync_page = affs_sync_page_ofs,
 781         .write_begin = affs_write_begin_ofs,
 782         .write_end = affs_write_end_ofs
 783 };
 784
 785 /* Free any preallocated blocks. */
 786
 787 void
 788 affs_free_prealloc(struct inode *inode)
 789 {
 790         struct super_block *sb = inode->i_sb;
 791
 792         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 793
 794         while (AFFS_I(inode)->i_pa_cnt) {
 795                 AFFS_I(inode)->i_pa_cnt--;
 796                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 797         }
 798 }
 799
 800 /* Truncate (or enlarge) a file to the requested size. */
 801
 802 void
 803 affs_truncate(struct inode *inode)
 804 {
 805         struct super_block *sb = inode->i_sb;
 806         u32 ext, ext_key;
 807         u32 last_blk, blkcnt, blk;
 808         u32 size;
 809         struct buffer_head *ext_bh;
 810         int i;
 811
 812         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 813                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 814
 815         last_blk = 0;
 816         ext = 0;
 817         if (inode->i_size) {
 818                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 819                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 820         }
 821
 822         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 823                 struct address_space *mapping = inode->i_mapping;
 824                 struct page *page;
 825                 void *fsdata;
 826                 u32 size = inode->i_size;
 827                 int res;
 828
 829                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 830                 if (!res)
 831                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 832                 else
 833                         inode->i_size = AFFS_I(inode)->mmu_private;
 834                 mark_inode_dirty(inode);
 835                 return;
 836         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 837                 return;
 838
 839         // lock cache
 840         ext_bh = affs_get_extblock(inode, ext);
 841         if (IS_ERR(ext_bh)) {
 842                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 843                              ext, PTR_ERR(ext_bh));
 844                 return;
 845         }
 846         if (AFFS_I(inode)->i_lc) {
 847                 /* clear linear cache */
 848                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 849                 if (AFFS_I(inode)->i_lc_size > i) {
 850                         AFFS_I(inode)->i_lc_size = i;
 851                         for (; i < AFFS_LC_SIZE; i++)
 852                                 AFFS_I(inode)->i_lc[i] = 0;
 853                 }
 854                 /* clear associative cache */
 855                 for (i = 0; i < AFFS_AC_SIZE; i++)
 856                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 857                                 AFFS_I(inode)->i_ac[i].ext = 0;
 858         }
 859         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 860
 861         blkcnt = AFFS_I(inode)->i_blkcnt;
 862         i = 0;
 863         blk = last_blk;
 864         if (inode->i_size) {
 865                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 866                 blk++;
 867         } else
 868                 AFFS_HEAD(ext_bh)->first_data = 0;
 869         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 870         size = AFFS_SB(sb)->s_hashsize;
 871         if (size > blkcnt - blk + i)
 872                 size = blkcnt - blk + i;
 873         for (; i < size; i++, blk++) {
 874                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 875                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 876         }
 877         AFFS_TAIL(sb, ext_bh)->extension = 0;
 878         affs_fix_checksum(sb, ext_bh);
 879         mark_buffer_dirty_inode(ext_bh, inode);
 880         affs_brelse(ext_bh);
 881
 882         if (inode->i_size) {
 883                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 884                 AFFS_I(inode)->i_extcnt = ext + 1;
 885                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 886                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 887                         u32 tmp;
 888                         if (IS_ERR(ext_bh)) {
 889                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 890                                              ext, PTR_ERR(ext_bh));
 891                                 return;
 892                         }
 893                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 894                         AFFS_DATA_HEAD(bh)->next = 0;
 895                         affs_adjust_checksum(bh, -tmp);
 896                         affs_brelse(bh);
 897                 }
 898         } else {
 899                 AFFS_I(inode)->i_blkcnt = 0;
 900                 AFFS_I(inode)->i_extcnt = 1;
 901         }
 902         AFFS_I(inode)->mmu_private = inode->i_size;
 903         // unlock cache
 904
 905         while (ext_key) {
 906                 ext_bh = affs_bread(sb, ext_key);
 907                 size = AFFS_SB(sb)->s_hashsize;
 908                 if (size > blkcnt - blk)
 909                         size = blkcnt - blk;
 910                 for (i = 0; i < size; i++, blk++)
 911                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 912                 affs_free_block(sb, ext_key);
 913                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 914                 affs_brelse(ext_bh);
 915         }
 916         affs_free_prealloc(inode);
 917 }