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           = new_sync_read,
  31         .read_iter      = generic_file_read_iter,
  32         .write          = new_sync_write,
  33         .write_iter     = generic_file_write_iter,
  34         .mmap           = generic_file_mmap,
  35         .open           = affs_file_open,
  36         .release        = affs_file_release,
  37         .fsync          = affs_file_fsync,
  38         .splice_read    = generic_file_splice_read,
  39 };
  40
  41 const struct inode_operations affs_file_inode_operations = {
  42         .setattr        = affs_notify_change,
  43 };
  44
  45 static int
  46 affs_file_open(struct inode *inode, struct file *filp)
  47 {
  48         pr_debug("open(%lu,%d)\n",
  49                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  50         atomic_inc(&AFFS_I(inode)->i_opencnt);
  51         return 0;
  52 }
  53
  54 static int
  55 affs_file_release(struct inode *inode, struct file *filp)
  56 {
  57         pr_debug("release(%lu, %d)\n",
  58                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  59
  60         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  61                 mutex_lock(&inode->i_mutex);
  62                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  63                         affs_truncate(inode);
  64                 affs_free_prealloc(inode);
  65                 mutex_unlock(&inode->i_mutex);
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int
  72 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  73 {
  74         struct super_block      *sb = inode->i_sb;
  75         struct buffer_head      *bh;
  76         u32 lc_max;
  77         int i, j, key;
  78
  79         if (!AFFS_I(inode)->i_lc) {
  80                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  81                 if (!ptr)
  82                         return -ENOMEM;
  83                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  84                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  85         }
  86
  87         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  88
  89         if (AFFS_I(inode)->i_extcnt > lc_max) {
  90                 u32 lc_shift, lc_mask, tmp, off;
  91
  92                 /* need to recalculate linear cache, start from old size */
  93                 lc_shift = AFFS_I(inode)->i_lc_shift;
  94                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  95                 for (; tmp; tmp >>= 1)
  96                         lc_shift++;
  97                 lc_mask = (1 << lc_shift) - 1;
  98
  99                 /* fix idx and old size to new shift */
 100                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 101                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 102
 103                 /* first shrink old cache to make more space */
 104                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 105                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 106                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 107
 108                 AFFS_I(inode)->i_lc_shift = lc_shift;
 109                 AFFS_I(inode)->i_lc_mask = lc_mask;
 110         }
 111
 112         /* fill cache to the needed index */
 113         i = AFFS_I(inode)->i_lc_size;
 114         AFFS_I(inode)->i_lc_size = lc_idx + 1;
 115         for (; i <= lc_idx; i++) {
 116                 if (!i) {
 117                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
 118                         continue;
 119                 }
 120                 key = AFFS_I(inode)->i_lc[i - 1];
 121                 j = AFFS_I(inode)->i_lc_mask + 1;
 122                 // unlock cache
 123                 for (; j > 0; j--) {
 124                         bh = affs_bread(sb, key);
 125                         if (!bh)
 126                                 goto err;
 127                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 128                         affs_brelse(bh);
 129                 }
 130                 // lock cache
 131                 AFFS_I(inode)->i_lc[i] = key;
 132         }
 133
 134         return 0;
 135
 136 err:
 137         // lock cache
 138         return -EIO;
 139 }
 140
 141 static struct buffer_head *
 142 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 143 {
 144         struct super_block *sb = inode->i_sb;
 145         struct buffer_head *new_bh;
 146         u32 blocknr, tmp;
 147
 148         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 149         if (!blocknr)
 150                 return ERR_PTR(-ENOSPC);
 151
 152         new_bh = affs_getzeroblk(sb, blocknr);
 153         if (!new_bh) {
 154                 affs_free_block(sb, blocknr);
 155                 return ERR_PTR(-EIO);
 156         }
 157
 158         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 159         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 160         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 161         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 162         affs_fix_checksum(sb, new_bh);
 163
 164         mark_buffer_dirty_inode(new_bh, inode);
 165
 166         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 167         if (tmp)
 168                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 169         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 170         affs_adjust_checksum(bh, blocknr - tmp);
 171         mark_buffer_dirty_inode(bh, inode);
 172
 173         AFFS_I(inode)->i_extcnt++;
 174         mark_inode_dirty(inode);
 175
 176         return new_bh;
 177 }
 178
 179 static inline struct buffer_head *
 180 affs_get_extblock(struct inode *inode, u32 ext)
 181 {
 182         /* inline the simplest case: same extended block as last time */
 183         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 184         if (ext == AFFS_I(inode)->i_ext_last)
 185                 get_bh(bh);
 186         else
 187                 /* we have to do more (not inlined) */
 188                 bh = affs_get_extblock_slow(inode, ext);
 189
 190         return bh;
 191 }
 192
 193 static struct buffer_head *
 194 affs_get_extblock_slow(struct inode *inode, u32 ext)
 195 {
 196         struct super_block *sb = inode->i_sb;
 197         struct buffer_head *bh;
 198         u32 ext_key;
 199         u32 lc_idx, lc_off, ac_idx;
 200         u32 tmp, idx;
 201
 202         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 203                 /* read the next extended block from the current one */
 204                 bh = AFFS_I(inode)->i_ext_bh;
 205                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 206                 if (ext < AFFS_I(inode)->i_extcnt)
 207                         goto read_ext;
 208                 if (ext > AFFS_I(inode)->i_extcnt)
 209                         BUG();
 210                 bh = affs_alloc_extblock(inode, bh, ext);
 211                 if (IS_ERR(bh))
 212                         return bh;
 213                 goto store_ext;
 214         }
 215
 216         if (ext == 0) {
 217                 /* we seek back to the file header block */
 218                 ext_key = inode->i_ino;
 219                 goto read_ext;
 220         }
 221
 222         if (ext >= AFFS_I(inode)->i_extcnt) {
 223                 struct buffer_head *prev_bh;
 224
 225                 /* allocate a new extended block */
 226                 if (ext > AFFS_I(inode)->i_extcnt)
 227                         BUG();
 228
 229                 /* get previous extended block */
 230                 prev_bh = affs_get_extblock(inode, ext - 1);
 231                 if (IS_ERR(prev_bh))
 232                         return prev_bh;
 233                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 234                 affs_brelse(prev_bh);
 235                 if (IS_ERR(bh))
 236                         return bh;
 237                 goto store_ext;
 238         }
 239
 240 again:
 241         /* check if there is an extended cache and whether it's large enough */
 242         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 243         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 244
 245         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 246                 int err;
 247
 248                 err = affs_grow_extcache(inode, lc_idx);
 249                 if (err)
 250                         return ERR_PTR(err);
 251                 goto again;
 252         }
 253
 254         /* every n'th key we find in the linear cache */
 255         if (!lc_off) {
 256                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 257                 goto read_ext;
 258         }
 259
 260         /* maybe it's still in the associative cache */
 261         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 262         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 263                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 264                 goto read_ext;
 265         }
 266
 267         /* try to find one of the previous extended blocks */
 268         tmp = ext;
 269         idx = ac_idx;
 270         while (--tmp, --lc_off > 0) {
 271                 idx = (idx - 1) & AFFS_AC_MASK;
 272                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 273                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 274                         goto find_ext;
 275                 }
 276         }
 277
 278         /* fall back to the linear cache */
 279         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 280 find_ext:
 281         /* read all extended blocks until we find the one we need */
 282         //unlock cache
 283         do {
 284                 bh = affs_bread(sb, ext_key);
 285                 if (!bh)
 286                         goto err_bread;
 287                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 288                 affs_brelse(bh);
 289                 tmp++;
 290         } while (tmp < ext);
 291         //lock cache
 292
 293         /* store it in the associative cache */
 294         // recalculate ac_idx?
 295         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 296         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 297
 298 read_ext:
 299         /* finally read the right extended block */
 300         //unlock cache
 301         bh = affs_bread(sb, ext_key);
 302         if (!bh)
 303                 goto err_bread;
 304         //lock cache
 305
 306 store_ext:
 307         /* release old cached extended block and store the new one */
 308         affs_brelse(AFFS_I(inode)->i_ext_bh);
 309         AFFS_I(inode)->i_ext_last = ext;
 310         AFFS_I(inode)->i_ext_bh = bh;
 311         get_bh(bh);
 312
 313         return bh;
 314
 315 err_bread:
 316         affs_brelse(bh);
 317         return ERR_PTR(-EIO);
 318 }
 319
 320 static int
 321 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 322 {
 323         struct super_block      *sb = inode->i_sb;
 324         struct buffer_head      *ext_bh;
 325         u32                      ext;
 326
 327         pr_debug("%s(%u, %lu)\n",
 328                  __func__, (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 void affs_write_failed(struct address_space *mapping, loff_t to)
 406 {
 407         struct inode *inode = mapping->host;
 408
 409         if (to > inode->i_size) {
 410                 truncate_pagecache(inode, inode->i_size);
 411                 affs_truncate(inode);
 412         }
 413 }
 414
 415 static int affs_write_begin(struct file *file, struct address_space *mapping,
 416                         loff_t pos, unsigned len, unsigned flags,
 417                         struct page **pagep, void **fsdata)
 418 {
 419         int ret;
 420
 421         *pagep = NULL;
 422         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 423                                 affs_get_block,
 424                                 &AFFS_I(mapping->host)->mmu_private);
 425         if (unlikely(ret))
 426                 affs_write_failed(mapping, pos + len);
 427
 428         return ret;
 429 }
 430
 431 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 432 {
 433         return generic_block_bmap(mapping,block,affs_get_block);
 434 }
 435
 436 const struct address_space_operations affs_aops = {
 437         .readpage = affs_readpage,
 438         .writepage = affs_writepage,
 439         .write_begin = affs_write_begin,
 440         .write_end = generic_write_end,
 441         .bmap = _affs_bmap
 442 };
 443
 444 static inline struct buffer_head *
 445 affs_bread_ino(struct inode *inode, int block, int create)
 446 {
 447         struct buffer_head *bh, tmp_bh;
 448         int err;
 449
 450         tmp_bh.b_state = 0;
 451         err = affs_get_block(inode, block, &tmp_bh, create);
 452         if (!err) {
 453                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 454                 if (bh) {
 455                         bh->b_state |= tmp_bh.b_state;
 456                         return bh;
 457                 }
 458                 err = -EIO;
 459         }
 460         return ERR_PTR(err);
 461 }
 462
 463 static inline struct buffer_head *
 464 affs_getzeroblk_ino(struct inode *inode, int block)
 465 {
 466         struct buffer_head *bh, tmp_bh;
 467         int err;
 468
 469         tmp_bh.b_state = 0;
 470         err = affs_get_block(inode, block, &tmp_bh, 1);
 471         if (!err) {
 472                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 473                 if (bh) {
 474                         bh->b_state |= tmp_bh.b_state;
 475                         return bh;
 476                 }
 477                 err = -EIO;
 478         }
 479         return ERR_PTR(err);
 480 }
 481
 482 static inline struct buffer_head *
 483 affs_getemptyblk_ino(struct inode *inode, int block)
 484 {
 485         struct buffer_head *bh, tmp_bh;
 486         int err;
 487
 488         tmp_bh.b_state = 0;
 489         err = affs_get_block(inode, block, &tmp_bh, 1);
 490         if (!err) {
 491                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 492                 if (bh) {
 493                         bh->b_state |= tmp_bh.b_state;
 494                         return bh;
 495                 }
 496                 err = -EIO;
 497         }
 498         return ERR_PTR(err);
 499 }
 500
 501 static int
 502 affs_do_readpage_ofs(struct page *page, unsigned to)
 503 {
 504         struct inode *inode = page->mapping->host;
 505         struct super_block *sb = inode->i_sb;
 506         struct buffer_head *bh;
 507         char *data;
 508         unsigned pos = 0;
 509         u32 bidx, boff, bsize;
 510         u32 tmp;
 511
 512         pr_debug("%s(%u, %ld, 0, %d)\n", __func__, (u32)inode->i_ino,
 513                  page->index, to);
 514         BUG_ON(to > PAGE_CACHE_SIZE);
 515         kmap(page);
 516         data = page_address(page);
 517         bsize = AFFS_SB(sb)->s_data_blksize;
 518         tmp = page->index << PAGE_CACHE_SHIFT;
 519         bidx = tmp / bsize;
 520         boff = tmp % bsize;
 521
 522         while (pos < to) {
 523                 bh = affs_bread_ino(inode, bidx, 0);
 524                 if (IS_ERR(bh))
 525                         return PTR_ERR(bh);
 526                 tmp = min(bsize - boff, to - pos);
 527                 BUG_ON(pos + tmp > to || tmp > bsize);
 528                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 529                 affs_brelse(bh);
 530                 bidx++;
 531                 pos += tmp;
 532                 boff = 0;
 533         }
 534         flush_dcache_page(page);
 535         kunmap(page);
 536         return 0;
 537 }
 538
 539 static int
 540 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 541 {
 542         struct super_block *sb = inode->i_sb;
 543         struct buffer_head *bh, *prev_bh;
 544         u32 bidx, boff;
 545         u32 size, bsize;
 546         u32 tmp;
 547
 548         pr_debug("%s(%u, %d)\n", __func__, (u32)inode->i_ino, newsize);
 549         bsize = AFFS_SB(sb)->s_data_blksize;
 550         bh = NULL;
 551         size = AFFS_I(inode)->mmu_private;
 552         bidx = size / bsize;
 553         boff = size % bsize;
 554         if (boff) {
 555                 bh = affs_bread_ino(inode, bidx, 0);
 556                 if (IS_ERR(bh))
 557                         return PTR_ERR(bh);
 558                 tmp = min(bsize - boff, newsize - size);
 559                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 560                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 561                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 562                 affs_fix_checksum(sb, bh);
 563                 mark_buffer_dirty_inode(bh, inode);
 564                 size += tmp;
 565                 bidx++;
 566         } else if (bidx) {
 567                 bh = affs_bread_ino(inode, bidx - 1, 0);
 568                 if (IS_ERR(bh))
 569                         return PTR_ERR(bh);
 570         }
 571
 572         while (size < newsize) {
 573                 prev_bh = bh;
 574                 bh = affs_getzeroblk_ino(inode, bidx);
 575                 if (IS_ERR(bh))
 576                         goto out;
 577                 tmp = min(bsize, newsize - size);
 578                 BUG_ON(tmp > bsize);
 579                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 580                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 581                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 582                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 583                 affs_fix_checksum(sb, bh);
 584                 bh->b_state &= ~(1UL << BH_New);
 585                 mark_buffer_dirty_inode(bh, inode);
 586                 if (prev_bh) {
 587                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 588
 589                         if (tmp_next)
 590                                 affs_warning(sb, "extent_file_ofs",
 591                                              "next block already set for %d (%d)",
 592                                              bidx, tmp_next);
 593                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 594                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 595                         mark_buffer_dirty_inode(prev_bh, inode);
 596                         affs_brelse(prev_bh);
 597                 }
 598                 size += bsize;
 599                 bidx++;
 600         }
 601         affs_brelse(bh);
 602         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 603         return 0;
 604
 605 out:
 606         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 607         return PTR_ERR(bh);
 608 }
 609
 610 static int
 611 affs_readpage_ofs(struct file *file, struct page *page)
 612 {
 613         struct inode *inode = page->mapping->host;
 614         u32 to;
 615         int err;
 616
 617         pr_debug("%s(%u, %ld)\n", __func__, (u32)inode->i_ino, page->index);
 618         to = PAGE_CACHE_SIZE;
 619         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 620                 to = inode->i_size & ~PAGE_CACHE_MASK;
 621                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 622         }
 623
 624         err = affs_do_readpage_ofs(page, to);
 625         if (!err)
 626                 SetPageUptodate(page);
 627         unlock_page(page);
 628         return err;
 629 }
 630
 631 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 632                                 loff_t pos, unsigned len, unsigned flags,
 633                                 struct page **pagep, void **fsdata)
 634 {
 635         struct inode *inode = mapping->host;
 636         struct page *page;
 637         pgoff_t index;
 638         int err = 0;
 639
 640         pr_debug("%s(%u, %llu, %llu)\n", __func__, (u32)inode->i_ino,
 641                  (unsigned long long)pos, (unsigned long long)pos + len);
 642         if (pos > AFFS_I(inode)->mmu_private) {
 643                 /* XXX: this probably leaves a too-big i_size in case of
 644                  * failure. Should really be updating i_size at write_end time
 645                  */
 646                 err = affs_extent_file_ofs(inode, pos);
 647                 if (err)
 648                         return err;
 649         }
 650
 651         index = pos >> PAGE_CACHE_SHIFT;
 652         page = grab_cache_page_write_begin(mapping, index, flags);
 653         if (!page)
 654                 return -ENOMEM;
 655         *pagep = page;
 656
 657         if (PageUptodate(page))
 658                 return 0;
 659
 660         /* XXX: inefficient but safe in the face of short writes */
 661         err = affs_do_readpage_ofs(page, PAGE_CACHE_SIZE);
 662         if (err) {
 663                 unlock_page(page);
 664                 page_cache_release(page);
 665         }
 666         return err;
 667 }
 668
 669 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 670                                 loff_t pos, unsigned len, unsigned copied,
 671                                 struct page *page, void *fsdata)
 672 {
 673         struct inode *inode = mapping->host;
 674         struct super_block *sb = inode->i_sb;
 675         struct buffer_head *bh, *prev_bh;
 676         char *data;
 677         u32 bidx, boff, bsize;
 678         unsigned from, to;
 679         u32 tmp;
 680         int written;
 681
 682         from = pos & (PAGE_CACHE_SIZE - 1);
 683         to = pos + len;
 684         /*
 685          * XXX: not sure if this can handle short copies (len < copied), but
 686          * we don't have to, because the page should always be uptodate here,
 687          * due to write_begin.
 688          */
 689
 690         pr_debug("%s(%u, %llu, %llu)\n",
 691                  __func__, (u32)inode->i_ino, (unsigned long long)pos,
 692                 (unsigned long long)pos + len);
 693         bsize = AFFS_SB(sb)->s_data_blksize;
 694         data = page_address(page);
 695
 696         bh = NULL;
 697         written = 0;
 698         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 699         bidx = tmp / bsize;
 700         boff = tmp % bsize;
 701         if (boff) {
 702                 bh = affs_bread_ino(inode, bidx, 0);
 703                 if (IS_ERR(bh))
 704                         return PTR_ERR(bh);
 705                 tmp = min(bsize - boff, to - from);
 706                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 707                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 708                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 709                 affs_fix_checksum(sb, bh);
 710                 mark_buffer_dirty_inode(bh, inode);
 711                 written += tmp;
 712                 from += tmp;
 713                 bidx++;
 714         } else if (bidx) {
 715                 bh = affs_bread_ino(inode, bidx - 1, 0);
 716                 if (IS_ERR(bh))
 717                         return PTR_ERR(bh);
 718         }
 719         while (from + bsize <= to) {
 720                 prev_bh = bh;
 721                 bh = affs_getemptyblk_ino(inode, bidx);
 722                 if (IS_ERR(bh))
 723                         goto out;
 724                 memcpy(AFFS_DATA(bh), data + from, bsize);
 725                 if (buffer_new(bh)) {
 726                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 727                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 728                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 729                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 730                         AFFS_DATA_HEAD(bh)->next = 0;
 731                         bh->b_state &= ~(1UL << BH_New);
 732                         if (prev_bh) {
 733                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 734
 735                                 if (tmp_next)
 736                                         affs_warning(sb, "commit_write_ofs",
 737                                                      "next block already set for %d (%d)",
 738                                                      bidx, tmp_next);
 739                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 740                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 741                                 mark_buffer_dirty_inode(prev_bh, inode);
 742                         }
 743                 }
 744                 affs_brelse(prev_bh);
 745                 affs_fix_checksum(sb, bh);
 746                 mark_buffer_dirty_inode(bh, inode);
 747                 written += bsize;
 748                 from += bsize;
 749                 bidx++;
 750         }
 751         if (from < to) {
 752                 prev_bh = bh;
 753                 bh = affs_bread_ino(inode, bidx, 1);
 754                 if (IS_ERR(bh))
 755                         goto out;
 756                 tmp = min(bsize, to - from);
 757                 BUG_ON(tmp > bsize);
 758                 memcpy(AFFS_DATA(bh), data + from, tmp);
 759                 if (buffer_new(bh)) {
 760                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 761                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 762                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 763                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 764                         AFFS_DATA_HEAD(bh)->next = 0;
 765                         bh->b_state &= ~(1UL << BH_New);
 766                         if (prev_bh) {
 767                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 768
 769                                 if (tmp_next)
 770                                         affs_warning(sb, "commit_write_ofs",
 771                                                      "next block already set for %d (%d)",
 772                                                      bidx, tmp_next);
 773                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 774                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 775                                 mark_buffer_dirty_inode(prev_bh, inode);
 776                         }
 777                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 778                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 779                 affs_brelse(prev_bh);
 780                 affs_fix_checksum(sb, bh);
 781                 mark_buffer_dirty_inode(bh, inode);
 782                 written += tmp;
 783                 from += tmp;
 784                 bidx++;
 785         }
 786         SetPageUptodate(page);
 787
 788 done:
 789         affs_brelse(bh);
 790         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 791         if (tmp > inode->i_size)
 792                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 793
 794         unlock_page(page);
 795         page_cache_release(page);
 796
 797         return written;
 798
 799 out:
 800         bh = prev_bh;
 801         if (!written)
 802                 written = PTR_ERR(bh);
 803         goto done;
 804 }
 805
 806 const struct address_space_operations affs_aops_ofs = {
 807         .readpage = affs_readpage_ofs,
 808         //.writepage = affs_writepage_ofs,
 809         .write_begin = affs_write_begin_ofs,
 810         .write_end = affs_write_end_ofs
 811 };
 812
 813 /* Free any preallocated blocks. */
 814
 815 void
 816 affs_free_prealloc(struct inode *inode)
 817 {
 818         struct super_block *sb = inode->i_sb;
 819
 820         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 821
 822         while (AFFS_I(inode)->i_pa_cnt) {
 823                 AFFS_I(inode)->i_pa_cnt--;
 824                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 825         }
 826 }
 827
 828 /* Truncate (or enlarge) a file to the requested size. */
 829
 830 void
 831 affs_truncate(struct inode *inode)
 832 {
 833         struct super_block *sb = inode->i_sb;
 834         u32 ext, ext_key;
 835         u32 last_blk, blkcnt, blk;
 836         u32 size;
 837         struct buffer_head *ext_bh;
 838         int i;
 839
 840         pr_debug("truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 841                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 842
 843         last_blk = 0;
 844         ext = 0;
 845         if (inode->i_size) {
 846                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 847                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 848         }
 849
 850         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 851                 struct address_space *mapping = inode->i_mapping;
 852                 struct page *page;
 853                 void *fsdata;
 854                 loff_t isize = inode->i_size;
 855                 int res;
 856
 857                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 858                 if (!res)
 859                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 860                 else
 861                         inode->i_size = AFFS_I(inode)->mmu_private;
 862                 mark_inode_dirty(inode);
 863                 return;
 864         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 865                 return;
 866
 867         // lock cache
 868         ext_bh = affs_get_extblock(inode, ext);
 869         if (IS_ERR(ext_bh)) {
 870                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 871                              ext, PTR_ERR(ext_bh));
 872                 return;
 873         }
 874         if (AFFS_I(inode)->i_lc) {
 875                 /* clear linear cache */
 876                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 877                 if (AFFS_I(inode)->i_lc_size > i) {
 878                         AFFS_I(inode)->i_lc_size = i;
 879                         for (; i < AFFS_LC_SIZE; i++)
 880                                 AFFS_I(inode)->i_lc[i] = 0;
 881                 }
 882                 /* clear associative cache */
 883                 for (i = 0; i < AFFS_AC_SIZE; i++)
 884                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 885                                 AFFS_I(inode)->i_ac[i].ext = 0;
 886         }
 887         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 888
 889         blkcnt = AFFS_I(inode)->i_blkcnt;
 890         i = 0;
 891         blk = last_blk;
 892         if (inode->i_size) {
 893                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 894                 blk++;
 895         } else
 896                 AFFS_HEAD(ext_bh)->first_data = 0;
 897         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 898         size = AFFS_SB(sb)->s_hashsize;
 899         if (size > blkcnt - blk + i)
 900                 size = blkcnt - blk + i;
 901         for (; i < size; i++, blk++) {
 902                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 903                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 904         }
 905         AFFS_TAIL(sb, ext_bh)->extension = 0;
 906         affs_fix_checksum(sb, ext_bh);
 907         mark_buffer_dirty_inode(ext_bh, inode);
 908         affs_brelse(ext_bh);
 909
 910         if (inode->i_size) {
 911                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 912                 AFFS_I(inode)->i_extcnt = ext + 1;
 913                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 914                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 915                         u32 tmp;
 916                         if (IS_ERR(bh)) {
 917                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 918                                              ext, PTR_ERR(bh));
 919                                 return;
 920                         }
 921                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 922                         AFFS_DATA_HEAD(bh)->next = 0;
 923                         affs_adjust_checksum(bh, -tmp);
 924                         affs_brelse(bh);
 925                 }
 926         } else {
 927                 AFFS_I(inode)->i_blkcnt = 0;
 928                 AFFS_I(inode)->i_extcnt = 1;
 929         }
 930         AFFS_I(inode)->mmu_private = inode->i_size;
 931         // unlock cache
 932
 933         while (ext_key) {
 934                 ext_bh = affs_bread(sb, ext_key);
 935                 size = AFFS_SB(sb)->s_hashsize;
 936                 if (size > blkcnt - blk)
 937                         size = blkcnt - blk;
 938                 for (i = 0; i < size; i++, blk++)
 939                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 940                 affs_free_block(sb, ext_key);
 941                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 942                 affs_brelse(ext_bh);
 943         }
 944         affs_free_prealloc(inode);
 945 }
 946
 947 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 948 {
 949         struct inode *inode = filp->f_mapping->host;
 950         int ret, err;
 951
 952         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 953         if (err)
 954                 return err;
 955
 956         mutex_lock(&inode->i_mutex);
 957         ret = write_inode_now(inode, 0);
 958         err = sync_blockdev(inode->i_sb->s_bdev);
 959         if (!ret)
 960                 ret = err;
 961         mutex_unlock(&inode->i_mutex);
 962         return ret;
 963 }