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 struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  22
  23 static int
  24 affs_file_open(struct inode *inode, struct file *filp)
  25 {
  26         pr_debug("open(%lu,%d)\n",
  27                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  28         atomic_inc(&AFFS_I(inode)->i_opencnt);
  29         return 0;
  30 }
  31
  32 static int
  33 affs_file_release(struct inode *inode, struct file *filp)
  34 {
  35         pr_debug("release(%lu, %d)\n",
  36                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  37
  38         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  39                 mutex_lock(&inode->i_mutex);
  40                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  41                         affs_truncate(inode);
  42                 affs_free_prealloc(inode);
  43                 mutex_unlock(&inode->i_mutex);
  44         }
  45
  46         return 0;
  47 }
  48
  49 static int
  50 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  51 {
  52         struct super_block      *sb = inode->i_sb;
  53         struct buffer_head      *bh;
  54         u32 lc_max;
  55         int i, j, key;
  56
  57         if (!AFFS_I(inode)->i_lc) {
  58                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  59                 if (!ptr)
  60                         return -ENOMEM;
  61                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  62                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  63         }
  64
  65         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  66
  67         if (AFFS_I(inode)->i_extcnt > lc_max) {
  68                 u32 lc_shift, lc_mask, tmp, off;
  69
  70                 /* need to recalculate linear cache, start from old size */
  71                 lc_shift = AFFS_I(inode)->i_lc_shift;
  72                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  73                 for (; tmp; tmp >>= 1)
  74                         lc_shift++;
  75                 lc_mask = (1 << lc_shift) - 1;
  76
  77                 /* fix idx and old size to new shift */
  78                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  80
  81                 /* first shrink old cache to make more space */
  82                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  83                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  84                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  85
  86                 AFFS_I(inode)->i_lc_shift = lc_shift;
  87                 AFFS_I(inode)->i_lc_mask = lc_mask;
  88         }
  89
  90         /* fill cache to the needed index */
  91         i = AFFS_I(inode)->i_lc_size;
  92         AFFS_I(inode)->i_lc_size = lc_idx + 1;
  93         for (; i <= lc_idx; i++) {
  94                 if (!i) {
  95                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
  96                         continue;
  97                 }
  98                 key = AFFS_I(inode)->i_lc[i - 1];
  99                 j = AFFS_I(inode)->i_lc_mask + 1;
 100                 // unlock cache
 101                 for (; j > 0; j--) {
 102                         bh = affs_bread(sb, key);
 103                         if (!bh)
 104                                 goto err;
 105                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 106                         affs_brelse(bh);
 107                 }
 108                 // lock cache
 109                 AFFS_I(inode)->i_lc[i] = key;
 110         }
 111
 112         return 0;
 113
 114 err:
 115         // lock cache
 116         return -EIO;
 117 }
 118
 119 static struct buffer_head *
 120 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 121 {
 122         struct super_block *sb = inode->i_sb;
 123         struct buffer_head *new_bh;
 124         u32 blocknr, tmp;
 125
 126         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 127         if (!blocknr)
 128                 return ERR_PTR(-ENOSPC);
 129
 130         new_bh = affs_getzeroblk(sb, blocknr);
 131         if (!new_bh) {
 132                 affs_free_block(sb, blocknr);
 133                 return ERR_PTR(-EIO);
 134         }
 135
 136         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 137         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 138         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 139         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 140         affs_fix_checksum(sb, new_bh);
 141
 142         mark_buffer_dirty_inode(new_bh, inode);
 143
 144         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 145         if (tmp)
 146                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 147         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 148         affs_adjust_checksum(bh, blocknr - tmp);
 149         mark_buffer_dirty_inode(bh, inode);
 150
 151         AFFS_I(inode)->i_extcnt++;
 152         mark_inode_dirty(inode);
 153
 154         return new_bh;
 155 }
 156
 157 static inline struct buffer_head *
 158 affs_get_extblock(struct inode *inode, u32 ext)
 159 {
 160         /* inline the simplest case: same extended block as last time */
 161         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 162         if (ext == AFFS_I(inode)->i_ext_last)
 163                 get_bh(bh);
 164         else
 165                 /* we have to do more (not inlined) */
 166                 bh = affs_get_extblock_slow(inode, ext);
 167
 168         return bh;
 169 }
 170
 171 static struct buffer_head *
 172 affs_get_extblock_slow(struct inode *inode, u32 ext)
 173 {
 174         struct super_block *sb = inode->i_sb;
 175         struct buffer_head *bh;
 176         u32 ext_key;
 177         u32 lc_idx, lc_off, ac_idx;
 178         u32 tmp, idx;
 179
 180         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 181                 /* read the next extended block from the current one */
 182                 bh = AFFS_I(inode)->i_ext_bh;
 183                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 184                 if (ext < AFFS_I(inode)->i_extcnt)
 185                         goto read_ext;
 186                 if (ext > AFFS_I(inode)->i_extcnt)
 187                         BUG();
 188                 bh = affs_alloc_extblock(inode, bh, ext);
 189                 if (IS_ERR(bh))
 190                         return bh;
 191                 goto store_ext;
 192         }
 193
 194         if (ext == 0) {
 195                 /* we seek back to the file header block */
 196                 ext_key = inode->i_ino;
 197                 goto read_ext;
 198         }
 199
 200         if (ext >= AFFS_I(inode)->i_extcnt) {
 201                 struct buffer_head *prev_bh;
 202
 203                 /* allocate a new extended block */
 204                 if (ext > AFFS_I(inode)->i_extcnt)
 205                         BUG();
 206
 207                 /* get previous extended block */
 208                 prev_bh = affs_get_extblock(inode, ext - 1);
 209                 if (IS_ERR(prev_bh))
 210                         return prev_bh;
 211                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 212                 affs_brelse(prev_bh);
 213                 if (IS_ERR(bh))
 214                         return bh;
 215                 goto store_ext;
 216         }
 217
 218 again:
 219         /* check if there is an extended cache and whether it's large enough */
 220         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 221         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 222
 223         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 224                 int err;
 225
 226                 err = affs_grow_extcache(inode, lc_idx);
 227                 if (err)
 228                         return ERR_PTR(err);
 229                 goto again;
 230         }
 231
 232         /* every n'th key we find in the linear cache */
 233         if (!lc_off) {
 234                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 235                 goto read_ext;
 236         }
 237
 238         /* maybe it's still in the associative cache */
 239         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 240         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 241                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 242                 goto read_ext;
 243         }
 244
 245         /* try to find one of the previous extended blocks */
 246         tmp = ext;
 247         idx = ac_idx;
 248         while (--tmp, --lc_off > 0) {
 249                 idx = (idx - 1) & AFFS_AC_MASK;
 250                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 251                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 252                         goto find_ext;
 253                 }
 254         }
 255
 256         /* fall back to the linear cache */
 257         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 258 find_ext:
 259         /* read all extended blocks until we find the one we need */
 260         //unlock cache
 261         do {
 262                 bh = affs_bread(sb, ext_key);
 263                 if (!bh)
 264                         goto err_bread;
 265                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 266                 affs_brelse(bh);
 267                 tmp++;
 268         } while (tmp < ext);
 269         //lock cache
 270
 271         /* store it in the associative cache */
 272         // recalculate ac_idx?
 273         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 274         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 275
 276 read_ext:
 277         /* finally read the right extended block */
 278         //unlock cache
 279         bh = affs_bread(sb, ext_key);
 280         if (!bh)
 281                 goto err_bread;
 282         //lock cache
 283
 284 store_ext:
 285         /* release old cached extended block and store the new one */
 286         affs_brelse(AFFS_I(inode)->i_ext_bh);
 287         AFFS_I(inode)->i_ext_last = ext;
 288         AFFS_I(inode)->i_ext_bh = bh;
 289         get_bh(bh);
 290
 291         return bh;
 292
 293 err_bread:
 294         affs_brelse(bh);
 295         return ERR_PTR(-EIO);
 296 }
 297
 298 static int
 299 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 300 {
 301         struct super_block      *sb = inode->i_sb;
 302         struct buffer_head      *ext_bh;
 303         u32                      ext;
 304
 305         pr_debug("%s(%u, %lu)\n",
 306                  __func__, (u32)inode->i_ino, (unsigned long)block);
 307
 308         BUG_ON(block > (sector_t)0x7fffffffUL);
 309
 310         if (block >= AFFS_I(inode)->i_blkcnt) {
 311                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 312                         goto err_big;
 313         } else
 314                 create = 0;
 315
 316         //lock cache
 317         affs_lock_ext(inode);
 318
 319         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 320         block -= ext * AFFS_SB(sb)->s_hashsize;
 321         ext_bh = affs_get_extblock(inode, ext);
 322         if (IS_ERR(ext_bh))
 323                 goto err_ext;
 324         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 325
 326         if (create) {
 327                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 328                 if (!blocknr)
 329                         goto err_alloc;
 330                 set_buffer_new(bh_result);
 331                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 332                 AFFS_I(inode)->i_blkcnt++;
 333
 334                 /* store new block */
 335                 if (bh_result->b_blocknr)
 336                         affs_warning(sb, "get_block", "block already set (%lx)",
 337                                      (unsigned long)bh_result->b_blocknr);
 338                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 339                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 340                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 341                 bh_result->b_blocknr = blocknr;
 342
 343                 if (!block) {
 344                         /* insert first block into header block */
 345                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 346                         if (tmp)
 347                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 348                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 349                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 350                 }
 351         }
 352
 353         affs_brelse(ext_bh);
 354         //unlock cache
 355         affs_unlock_ext(inode);
 356         return 0;
 357
 358 err_big:
 359         affs_error(inode->i_sb, "get_block", "strange block request %d",
 360                    (int)block);
 361         return -EIO;
 362 err_ext:
 363         // unlock cache
 364         affs_unlock_ext(inode);
 365         return PTR_ERR(ext_bh);
 366 err_alloc:
 367         brelse(ext_bh);
 368         clear_buffer_mapped(bh_result);
 369         bh_result->b_bdev = NULL;
 370         // unlock cache
 371         affs_unlock_ext(inode);
 372         return -ENOSPC;
 373 }
 374
 375 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 376 {
 377         return block_write_full_page(page, affs_get_block, wbc);
 378 }
 379
 380 static int affs_readpage(struct file *file, struct page *page)
 381 {
 382         return block_read_full_page(page, affs_get_block);
 383 }
 384
 385 static void affs_write_failed(struct address_space *mapping, loff_t to)
 386 {
 387         struct inode *inode = mapping->host;
 388
 389         if (to > inode->i_size) {
 390                 truncate_pagecache(inode, inode->i_size);
 391                 affs_truncate(inode);
 392         }
 393 }
 394
 395 static int affs_write_begin(struct file *file, struct address_space *mapping,
 396                         loff_t pos, unsigned len, unsigned flags,
 397                         struct page **pagep, void **fsdata)
 398 {
 399         int ret;
 400
 401         *pagep = NULL;
 402         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 403                                 affs_get_block,
 404                                 &AFFS_I(mapping->host)->mmu_private);
 405         if (unlikely(ret))
 406                 affs_write_failed(mapping, pos + len);
 407
 408         return ret;
 409 }
 410
 411 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 412 {
 413         return generic_block_bmap(mapping,block,affs_get_block);
 414 }
 415
 416 const struct address_space_operations affs_aops = {
 417         .readpage = affs_readpage,
 418         .writepage = affs_writepage,
 419         .write_begin = affs_write_begin,
 420         .write_end = generic_write_end,
 421         .bmap = _affs_bmap
 422 };
 423
 424 static inline struct buffer_head *
 425 affs_bread_ino(struct inode *inode, int block, int create)
 426 {
 427         struct buffer_head *bh, tmp_bh;
 428         int err;
 429
 430         tmp_bh.b_state = 0;
 431         err = affs_get_block(inode, block, &tmp_bh, create);
 432         if (!err) {
 433                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 434                 if (bh) {
 435                         bh->b_state |= tmp_bh.b_state;
 436                         return bh;
 437                 }
 438                 err = -EIO;
 439         }
 440         return ERR_PTR(err);
 441 }
 442
 443 static inline struct buffer_head *
 444 affs_getzeroblk_ino(struct inode *inode, int block)
 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, 1);
 451         if (!err) {
 452                 bh = affs_getzeroblk(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_getemptyblk_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_getemptyblk(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 int
 482 affs_do_readpage_ofs(struct page *page, unsigned to)
 483 {
 484         struct inode *inode = page->mapping->host;
 485         struct super_block *sb = inode->i_sb;
 486         struct buffer_head *bh;
 487         char *data;
 488         unsigned pos = 0;
 489         u32 bidx, boff, bsize;
 490         u32 tmp;
 491
 492         pr_debug("%s(%u, %ld, 0, %d)\n", __func__, (u32)inode->i_ino,
 493                  page->index, to);
 494         BUG_ON(to > PAGE_CACHE_SIZE);
 495         kmap(page);
 496         data = page_address(page);
 497         bsize = AFFS_SB(sb)->s_data_blksize;
 498         tmp = page->index << PAGE_CACHE_SHIFT;
 499         bidx = tmp / bsize;
 500         boff = tmp % bsize;
 501
 502         while (pos < to) {
 503                 bh = affs_bread_ino(inode, bidx, 0);
 504                 if (IS_ERR(bh))
 505                         return PTR_ERR(bh);
 506                 tmp = min(bsize - boff, to - pos);
 507                 BUG_ON(pos + tmp > to || tmp > bsize);
 508                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 509                 affs_brelse(bh);
 510                 bidx++;
 511                 pos += tmp;
 512                 boff = 0;
 513         }
 514         flush_dcache_page(page);
 515         kunmap(page);
 516         return 0;
 517 }
 518
 519 static int
 520 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 521 {
 522         struct super_block *sb = inode->i_sb;
 523         struct buffer_head *bh, *prev_bh;
 524         u32 bidx, boff;
 525         u32 size, bsize;
 526         u32 tmp;
 527
 528         pr_debug("%s(%u, %d)\n", __func__, (u32)inode->i_ino, newsize);
 529         bsize = AFFS_SB(sb)->s_data_blksize;
 530         bh = NULL;
 531         size = AFFS_I(inode)->mmu_private;
 532         bidx = size / bsize;
 533         boff = size % bsize;
 534         if (boff) {
 535                 bh = affs_bread_ino(inode, bidx, 0);
 536                 if (IS_ERR(bh))
 537                         return PTR_ERR(bh);
 538                 tmp = min(bsize - boff, newsize - size);
 539                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 540                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 541                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 542                 affs_fix_checksum(sb, bh);
 543                 mark_buffer_dirty_inode(bh, inode);
 544                 size += tmp;
 545                 bidx++;
 546         } else if (bidx) {
 547                 bh = affs_bread_ino(inode, bidx - 1, 0);
 548                 if (IS_ERR(bh))
 549                         return PTR_ERR(bh);
 550         }
 551
 552         while (size < newsize) {
 553                 prev_bh = bh;
 554                 bh = affs_getzeroblk_ino(inode, bidx);
 555                 if (IS_ERR(bh))
 556                         goto out;
 557                 tmp = min(bsize, newsize - size);
 558                 BUG_ON(tmp > bsize);
 559                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 560                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 561                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 562                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 563                 affs_fix_checksum(sb, bh);
 564                 bh->b_state &= ~(1UL << BH_New);
 565                 mark_buffer_dirty_inode(bh, inode);
 566                 if (prev_bh) {
 567                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 568
 569                         if (tmp_next)
 570                                 affs_warning(sb, "extent_file_ofs",
 571                                              "next block already set for %d (%d)",
 572                                              bidx, tmp_next);
 573                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 574                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 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("%s(%u, %ld)\n", __func__, (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(page, 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("%s(%u, %llu, %llu)\n", __func__, (u32)inode->i_ino,
 621                  (unsigned long long)pos, (unsigned long long)pos + len);
 622         if (pos > AFFS_I(inode)->mmu_private) {
 623                 /* XXX: this probably leaves a too-big i_size in case of
 624                  * failure. Should really be updating i_size at write_end time
 625                  */
 626                 err = affs_extent_file_ofs(inode, pos);
 627                 if (err)
 628                         return err;
 629         }
 630
 631         index = pos >> PAGE_CACHE_SHIFT;
 632         page = grab_cache_page_write_begin(mapping, index, flags);
 633         if (!page)
 634                 return -ENOMEM;
 635         *pagep = page;
 636
 637         if (PageUptodate(page))
 638                 return 0;
 639
 640         /* XXX: inefficient but safe in the face of short writes */
 641         err = affs_do_readpage_ofs(page, PAGE_CACHE_SIZE);
 642         if (err) {
 643                 unlock_page(page);
 644                 page_cache_release(page);
 645         }
 646         return err;
 647 }
 648
 649 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 650                                 loff_t pos, unsigned len, unsigned copied,
 651                                 struct page *page, void *fsdata)
 652 {
 653         struct inode *inode = mapping->host;
 654         struct super_block *sb = inode->i_sb;
 655         struct buffer_head *bh, *prev_bh;
 656         char *data;
 657         u32 bidx, boff, bsize;
 658         unsigned from, to;
 659         u32 tmp;
 660         int written;
 661
 662         from = pos & (PAGE_CACHE_SIZE - 1);
 663         to = pos + len;
 664         /*
 665          * XXX: not sure if this can handle short copies (len < copied), but
 666          * we don't have to, because the page should always be uptodate here,
 667          * due to write_begin.
 668          */
 669
 670         pr_debug("%s(%u, %llu, %llu)\n",
 671                  __func__, (u32)inode->i_ino, (unsigned long long)pos,
 672                 (unsigned long long)pos + len);
 673         bsize = AFFS_SB(sb)->s_data_blksize;
 674         data = page_address(page);
 675
 676         bh = NULL;
 677         written = 0;
 678         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 679         bidx = tmp / bsize;
 680         boff = tmp % bsize;
 681         if (boff) {
 682                 bh = affs_bread_ino(inode, bidx, 0);
 683                 if (IS_ERR(bh))
 684                         return PTR_ERR(bh);
 685                 tmp = min(bsize - boff, to - from);
 686                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 687                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 688                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 689                 affs_fix_checksum(sb, bh);
 690                 mark_buffer_dirty_inode(bh, inode);
 691                 written += tmp;
 692                 from += tmp;
 693                 bidx++;
 694         } else if (bidx) {
 695                 bh = affs_bread_ino(inode, bidx - 1, 0);
 696                 if (IS_ERR(bh))
 697                         return PTR_ERR(bh);
 698         }
 699         while (from + bsize <= to) {
 700                 prev_bh = bh;
 701                 bh = affs_getemptyblk_ino(inode, bidx);
 702                 if (IS_ERR(bh))
 703                         goto out;
 704                 memcpy(AFFS_DATA(bh), data + from, bsize);
 705                 if (buffer_new(bh)) {
 706                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 707                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 708                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 709                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 710                         AFFS_DATA_HEAD(bh)->next = 0;
 711                         bh->b_state &= ~(1UL << BH_New);
 712                         if (prev_bh) {
 713                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 714
 715                                 if (tmp_next)
 716                                         affs_warning(sb, "commit_write_ofs",
 717                                                      "next block already set for %d (%d)",
 718                                                      bidx, tmp_next);
 719                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 720                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 721                                 mark_buffer_dirty_inode(prev_bh, inode);
 722                         }
 723                 }
 724                 affs_brelse(prev_bh);
 725                 affs_fix_checksum(sb, bh);
 726                 mark_buffer_dirty_inode(bh, inode);
 727                 written += bsize;
 728                 from += bsize;
 729                 bidx++;
 730         }
 731         if (from < to) {
 732                 prev_bh = bh;
 733                 bh = affs_bread_ino(inode, bidx, 1);
 734                 if (IS_ERR(bh))
 735                         goto out;
 736                 tmp = min(bsize, to - from);
 737                 BUG_ON(tmp > bsize);
 738                 memcpy(AFFS_DATA(bh), data + from, tmp);
 739                 if (buffer_new(bh)) {
 740                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 741                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 742                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 743                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 744                         AFFS_DATA_HEAD(bh)->next = 0;
 745                         bh->b_state &= ~(1UL << BH_New);
 746                         if (prev_bh) {
 747                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 748
 749                                 if (tmp_next)
 750                                         affs_warning(sb, "commit_write_ofs",
 751                                                      "next block already set for %d (%d)",
 752                                                      bidx, tmp_next);
 753                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 754                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 755                                 mark_buffer_dirty_inode(prev_bh, inode);
 756                         }
 757                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 758                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 759                 affs_brelse(prev_bh);
 760                 affs_fix_checksum(sb, bh);
 761                 mark_buffer_dirty_inode(bh, inode);
 762                 written += tmp;
 763                 from += tmp;
 764                 bidx++;
 765         }
 766         SetPageUptodate(page);
 767
 768 done:
 769         affs_brelse(bh);
 770         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 771         if (tmp > inode->i_size)
 772                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 773
 774         unlock_page(page);
 775         page_cache_release(page);
 776
 777         return written;
 778
 779 out:
 780         bh = prev_bh;
 781         if (!written)
 782                 written = PTR_ERR(bh);
 783         goto done;
 784 }
 785
 786 const struct address_space_operations affs_aops_ofs = {
 787         .readpage = affs_readpage_ofs,
 788         //.writepage = affs_writepage_ofs,
 789         .write_begin = affs_write_begin_ofs,
 790         .write_end = affs_write_end_ofs
 791 };
 792
 793 /* Free any preallocated blocks. */
 794
 795 void
 796 affs_free_prealloc(struct inode *inode)
 797 {
 798         struct super_block *sb = inode->i_sb;
 799
 800         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 801
 802         while (AFFS_I(inode)->i_pa_cnt) {
 803                 AFFS_I(inode)->i_pa_cnt--;
 804                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 805         }
 806 }
 807
 808 /* Truncate (or enlarge) a file to the requested size. */
 809
 810 void
 811 affs_truncate(struct inode *inode)
 812 {
 813         struct super_block *sb = inode->i_sb;
 814         u32 ext, ext_key;
 815         u32 last_blk, blkcnt, blk;
 816         u32 size;
 817         struct buffer_head *ext_bh;
 818         int i;
 819
 820         pr_debug("truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 821                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 822
 823         last_blk = 0;
 824         ext = 0;
 825         if (inode->i_size) {
 826                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 827                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 828         }
 829
 830         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 831                 struct address_space *mapping = inode->i_mapping;
 832                 struct page *page;
 833                 void *fsdata;
 834                 loff_t isize = inode->i_size;
 835                 int res;
 836
 837                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 838                 if (!res)
 839                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 840                 else
 841                         inode->i_size = AFFS_I(inode)->mmu_private;
 842                 mark_inode_dirty(inode);
 843                 return;
 844         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 845                 return;
 846
 847         // lock cache
 848         ext_bh = affs_get_extblock(inode, ext);
 849         if (IS_ERR(ext_bh)) {
 850                 affs_warning(sb, "truncate",
 851                              "unexpected read error for ext block %u (%ld)",
 852                              (unsigned int)ext, PTR_ERR(ext_bh));
 853                 return;
 854         }
 855         if (AFFS_I(inode)->i_lc) {
 856                 /* clear linear cache */
 857                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 858                 if (AFFS_I(inode)->i_lc_size > i) {
 859                         AFFS_I(inode)->i_lc_size = i;
 860                         for (; i < AFFS_LC_SIZE; i++)
 861                                 AFFS_I(inode)->i_lc[i] = 0;
 862                 }
 863                 /* clear associative cache */
 864                 for (i = 0; i < AFFS_AC_SIZE; i++)
 865                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 866                                 AFFS_I(inode)->i_ac[i].ext = 0;
 867         }
 868         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 869
 870         blkcnt = AFFS_I(inode)->i_blkcnt;
 871         i = 0;
 872         blk = last_blk;
 873         if (inode->i_size) {
 874                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 875                 blk++;
 876         } else
 877                 AFFS_HEAD(ext_bh)->first_data = 0;
 878         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 879         size = AFFS_SB(sb)->s_hashsize;
 880         if (size > blkcnt - blk + i)
 881                 size = blkcnt - blk + i;
 882         for (; i < size; i++, blk++) {
 883                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 884                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 885         }
 886         AFFS_TAIL(sb, ext_bh)->extension = 0;
 887         affs_fix_checksum(sb, ext_bh);
 888         mark_buffer_dirty_inode(ext_bh, inode);
 889         affs_brelse(ext_bh);
 890
 891         if (inode->i_size) {
 892                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 893                 AFFS_I(inode)->i_extcnt = ext + 1;
 894                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 895                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 896                         u32 tmp;
 897                         if (IS_ERR(bh)) {
 898                                 affs_warning(sb, "truncate",
 899                                              "unexpected read error for last block %u (%ld)",
 900                                              (unsigned int)ext, PTR_ERR(bh));
 901                                 return;
 902                         }
 903                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 904                         AFFS_DATA_HEAD(bh)->next = 0;
 905                         affs_adjust_checksum(bh, -tmp);
 906                         affs_brelse(bh);
 907                 }
 908         } else {
 909                 AFFS_I(inode)->i_blkcnt = 0;
 910                 AFFS_I(inode)->i_extcnt = 1;
 911         }
 912         AFFS_I(inode)->mmu_private = inode->i_size;
 913         // unlock cache
 914
 915         while (ext_key) {
 916                 ext_bh = affs_bread(sb, ext_key);
 917                 size = AFFS_SB(sb)->s_hashsize;
 918                 if (size > blkcnt - blk)
 919                         size = blkcnt - blk;
 920                 for (i = 0; i < size; i++, blk++)
 921                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 922                 affs_free_block(sb, ext_key);
 923                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 924                 affs_brelse(ext_bh);
 925         }
 926         affs_free_prealloc(inode);
 927 }
 928
 929 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 930 {
 931         struct inode *inode = filp->f_mapping->host;
 932         int ret, err;
 933
 934         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 935         if (err)
 936                 return err;
 937
 938         mutex_lock(&inode->i_mutex);
 939         ret = write_inode_now(inode, 0);
 940         err = sync_blockdev(inode->i_sb->s_bdev);
 941         if (!ret)
 942                 ret = err;
 943         mutex_unlock(&inode->i_mutex);
 944         return ret;
 945 }
 946 const struct file_operations affs_file_operations = {
 947         .llseek         = generic_file_llseek,
 948         .read           = new_sync_read,
 949         .read_iter      = generic_file_read_iter,
 950         .write          = new_sync_write,
 951         .write_iter     = generic_file_write_iter,
 952         .mmap           = generic_file_mmap,
 953         .open           = affs_file_open,
 954         .release        = affs_file_release,
 955         .fsync          = affs_file_fsync,
 956         .splice_read    = generic_file_splice_read,
 957 };
 958
 959 const struct inode_operations affs_file_inode_operations = {
 960         .setattr        = affs_notify_change,
 961 };