fs/affs/file.c

   1 /*
   2  *  linux/fs/affs/file.c
   3  *
   4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5  *
   6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7  *
   8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9  *
  10  *  (C) 1991  Linus Torvalds - minix filesystem
  11  *
  12  *  affs regular file handling primitives
  13  */
  14
  15 #include "affs.h"
  16
  17 #if PAGE_SIZE < 4096
  18 #error PAGE_SIZE must be at least 4096
  19 #endif
  20
  21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
  22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
  23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
  24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  25 static int affs_file_open(struct inode *inode, struct file *filp);
  26 static int affs_file_release(struct inode *inode, struct file *filp);
  27
  28 const struct file_operations affs_file_operations = {
  29         .llseek         = generic_file_llseek,
  30         .read           = do_sync_read,
  31         .aio_read       = generic_file_aio_read,
  32         .write          = do_sync_write,
  33         .aio_write      = generic_file_aio_write,
  34         .mmap           = generic_file_mmap,
  35         .open           = affs_file_open,
  36         .release        = affs_file_release,
  37         .fsync          = affs_file_fsync,
  38         .splice_read    = generic_file_splice_read,
  39 };
  40
  41 const struct inode_operations affs_file_inode_operations = {
  42         .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         int ret;
 410
 411         *pagep = NULL;
 412         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 413                                 affs_get_block,
 414                                 &AFFS_I(mapping->host)->mmu_private);
 415         if (unlikely(ret)) {
 416                 loff_t isize = mapping->host->i_size;
 417                 if (pos + len > isize)
 418                         vmtruncate(mapping->host, isize);
 419         }
 420
 421         return ret;
 422 }
 423
 424 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 425 {
 426         return generic_block_bmap(mapping,block,affs_get_block);
 427 }
 428
 429 const struct address_space_operations affs_aops = {
 430         .readpage = affs_readpage,
 431         .writepage = affs_writepage,
 432         .sync_page = block_sync_page,
 433         .write_begin = affs_write_begin,
 434         .write_end = generic_write_end,
 435         .bmap = _affs_bmap
 436 };
 437
 438 static inline struct buffer_head *
 439 affs_bread_ino(struct inode *inode, int block, int create)
 440 {
 441         struct buffer_head *bh, tmp_bh;
 442         int err;
 443
 444         tmp_bh.b_state = 0;
 445         err = affs_get_block(inode, block, &tmp_bh, create);
 446         if (!err) {
 447                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 448                 if (bh) {
 449                         bh->b_state |= tmp_bh.b_state;
 450                         return bh;
 451                 }
 452                 err = -EIO;
 453         }
 454         return ERR_PTR(err);
 455 }
 456
 457 static inline struct buffer_head *
 458 affs_getzeroblk_ino(struct inode *inode, int block)
 459 {
 460         struct buffer_head *bh, tmp_bh;
 461         int err;
 462
 463         tmp_bh.b_state = 0;
 464         err = affs_get_block(inode, block, &tmp_bh, 1);
 465         if (!err) {
 466                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 467                 if (bh) {
 468                         bh->b_state |= tmp_bh.b_state;
 469                         return bh;
 470                 }
 471                 err = -EIO;
 472         }
 473         return ERR_PTR(err);
 474 }
 475
 476 static inline struct buffer_head *
 477 affs_getemptyblk_ino(struct inode *inode, int block)
 478 {
 479         struct buffer_head *bh, tmp_bh;
 480         int err;
 481
 482         tmp_bh.b_state = 0;
 483         err = affs_get_block(inode, block, &tmp_bh, 1);
 484         if (!err) {
 485                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 486                 if (bh) {
 487                         bh->b_state |= tmp_bh.b_state;
 488                         return bh;
 489                 }
 490                 err = -EIO;
 491         }
 492         return ERR_PTR(err);
 493 }
 494
 495 static int
 496 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 497 {
 498         struct inode *inode = page->mapping->host;
 499         struct super_block *sb = inode->i_sb;
 500         struct buffer_head *bh;
 501         char *data;
 502         u32 bidx, boff, bsize;
 503         u32 tmp;
 504
 505         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 506         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
 507         kmap(page);
 508         data = page_address(page);
 509         bsize = AFFS_SB(sb)->s_data_blksize;
 510         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 511         bidx = tmp / bsize;
 512         boff = tmp % bsize;
 513
 514         while (from < to) {
 515                 bh = affs_bread_ino(inode, bidx, 0);
 516                 if (IS_ERR(bh))
 517                         return PTR_ERR(bh);
 518                 tmp = min(bsize - boff, to - from);
 519                 BUG_ON(from + tmp > to || tmp > bsize);
 520                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 521                 affs_brelse(bh);
 522                 bidx++;
 523                 from += tmp;
 524                 boff = 0;
 525         }
 526         flush_dcache_page(page);
 527         kunmap(page);
 528         return 0;
 529 }
 530
 531 static int
 532 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 533 {
 534         struct super_block *sb = inode->i_sb;
 535         struct buffer_head *bh, *prev_bh;
 536         u32 bidx, boff;
 537         u32 size, bsize;
 538         u32 tmp;
 539
 540         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 541         bsize = AFFS_SB(sb)->s_data_blksize;
 542         bh = NULL;
 543         size = AFFS_I(inode)->mmu_private;
 544         bidx = size / bsize;
 545         boff = size % bsize;
 546         if (boff) {
 547                 bh = affs_bread_ino(inode, bidx, 0);
 548                 if (IS_ERR(bh))
 549                         return PTR_ERR(bh);
 550                 tmp = min(bsize - boff, newsize - size);
 551                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 552                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 553                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 554                 affs_fix_checksum(sb, bh);
 555                 mark_buffer_dirty_inode(bh, inode);
 556                 size += tmp;
 557                 bidx++;
 558         } else if (bidx) {
 559                 bh = affs_bread_ino(inode, bidx - 1, 0);
 560                 if (IS_ERR(bh))
 561                         return PTR_ERR(bh);
 562         }
 563
 564         while (size < newsize) {
 565                 prev_bh = bh;
 566                 bh = affs_getzeroblk_ino(inode, bidx);
 567                 if (IS_ERR(bh))
 568                         goto out;
 569                 tmp = min(bsize, newsize - size);
 570                 BUG_ON(tmp > bsize);
 571                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 572                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 573                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 574                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 575                 affs_fix_checksum(sb, bh);
 576                 bh->b_state &= ~(1UL << BH_New);
 577                 mark_buffer_dirty_inode(bh, inode);
 578                 if (prev_bh) {
 579                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 580                         if (tmp)
 581                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 582                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 583                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 584                         mark_buffer_dirty_inode(prev_bh, inode);
 585                         affs_brelse(prev_bh);
 586                 }
 587                 size += bsize;
 588                 bidx++;
 589         }
 590         affs_brelse(bh);
 591         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 592         return 0;
 593
 594 out:
 595         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 596         return PTR_ERR(bh);
 597 }
 598
 599 static int
 600 affs_readpage_ofs(struct file *file, struct page *page)
 601 {
 602         struct inode *inode = page->mapping->host;
 603         u32 to;
 604         int err;
 605
 606         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 607         to = PAGE_CACHE_SIZE;
 608         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 609                 to = inode->i_size & ~PAGE_CACHE_MASK;
 610                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 611         }
 612
 613         err = affs_do_readpage_ofs(file, page, 0, to);
 614         if (!err)
 615                 SetPageUptodate(page);
 616         unlock_page(page);
 617         return err;
 618 }
 619
 620 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 621                                 loff_t pos, unsigned len, unsigned flags,
 622                                 struct page **pagep, void **fsdata)
 623 {
 624         struct inode *inode = mapping->host;
 625         struct page *page;
 626         pgoff_t index;
 627         int err = 0;
 628
 629         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 630         if (pos > AFFS_I(inode)->mmu_private) {
 631                 /* XXX: this probably leaves a too-big i_size in case of
 632                  * failure. Should really be updating i_size at write_end time
 633                  */
 634                 err = affs_extent_file_ofs(inode, pos);
 635                 if (err)
 636                         return err;
 637         }
 638
 639         index = pos >> PAGE_CACHE_SHIFT;
 640         page = grab_cache_page_write_begin(mapping, index, flags);
 641         if (!page)
 642                 return -ENOMEM;
 643         *pagep = page;
 644
 645         if (PageUptodate(page))
 646                 return 0;
 647
 648         /* XXX: inefficient but safe in the face of short writes */
 649         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
 650         if (err) {
 651                 unlock_page(page);
 652                 page_cache_release(page);
 653         }
 654         return err;
 655 }
 656
 657 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 658                                 loff_t pos, unsigned len, unsigned copied,
 659                                 struct page *page, void *fsdata)
 660 {
 661         struct inode *inode = mapping->host;
 662         struct super_block *sb = inode->i_sb;
 663         struct buffer_head *bh, *prev_bh;
 664         char *data;
 665         u32 bidx, boff, bsize;
 666         unsigned from, to;
 667         u32 tmp;
 668         int written;
 669
 670         from = pos & (PAGE_CACHE_SIZE - 1);
 671         to = pos + len;
 672         /*
 673          * XXX: not sure if this can handle short copies (len < copied), but
 674          * we don't have to, because the page should always be uptodate here,
 675          * due to write_begin.
 676          */
 677
 678         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 679         bsize = AFFS_SB(sb)->s_data_blksize;
 680         data = page_address(page);
 681
 682         bh = NULL;
 683         written = 0;
 684         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 685         bidx = tmp / bsize;
 686         boff = tmp % bsize;
 687         if (boff) {
 688                 bh = affs_bread_ino(inode, bidx, 0);
 689                 if (IS_ERR(bh))
 690                         return PTR_ERR(bh);
 691                 tmp = min(bsize - boff, to - from);
 692                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 693                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 694                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 695                 affs_fix_checksum(sb, bh);
 696                 mark_buffer_dirty_inode(bh, inode);
 697                 written += tmp;
 698                 from += tmp;
 699                 bidx++;
 700         } else if (bidx) {
 701                 bh = affs_bread_ino(inode, bidx - 1, 0);
 702                 if (IS_ERR(bh))
 703                         return PTR_ERR(bh);
 704         }
 705         while (from + bsize <= to) {
 706                 prev_bh = bh;
 707                 bh = affs_getemptyblk_ino(inode, bidx);
 708                 if (IS_ERR(bh))
 709                         goto out;
 710                 memcpy(AFFS_DATA(bh), data + from, bsize);
 711                 if (buffer_new(bh)) {
 712                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 713                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 714                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 715                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 716                         AFFS_DATA_HEAD(bh)->next = 0;
 717                         bh->b_state &= ~(1UL << BH_New);
 718                         if (prev_bh) {
 719                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 720                                 if (tmp)
 721                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 722                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 723                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 724                                 mark_buffer_dirty_inode(prev_bh, inode);
 725                         }
 726                 }
 727                 affs_brelse(prev_bh);
 728                 affs_fix_checksum(sb, bh);
 729                 mark_buffer_dirty_inode(bh, inode);
 730                 written += bsize;
 731                 from += bsize;
 732                 bidx++;
 733         }
 734         if (from < to) {
 735                 prev_bh = bh;
 736                 bh = affs_bread_ino(inode, bidx, 1);
 737                 if (IS_ERR(bh))
 738                         goto out;
 739                 tmp = min(bsize, to - from);
 740                 BUG_ON(tmp > bsize);
 741                 memcpy(AFFS_DATA(bh), data + from, tmp);
 742                 if (buffer_new(bh)) {
 743                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 744                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 745                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 746                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 747                         AFFS_DATA_HEAD(bh)->next = 0;
 748                         bh->b_state &= ~(1UL << BH_New);
 749                         if (prev_bh) {
 750                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 751                                 if (tmp)
 752                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 753                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 754                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 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         //.sync_page = affs_sync_page_ofs,
 790         .write_begin = affs_write_begin_ofs,
 791         .write_end = affs_write_end_ofs
 792 };
 793
 794 /* Free any preallocated blocks. */
 795
 796 void
 797 affs_free_prealloc(struct inode *inode)
 798 {
 799         struct super_block *sb = inode->i_sb;
 800
 801         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 802
 803         while (AFFS_I(inode)->i_pa_cnt) {
 804                 AFFS_I(inode)->i_pa_cnt--;
 805                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 806         }
 807 }
 808
 809 /* Truncate (or enlarge) a file to the requested size. */
 810
 811 void
 812 affs_truncate(struct inode *inode)
 813 {
 814         struct super_block *sb = inode->i_sb;
 815         u32 ext, ext_key;
 816         u32 last_blk, blkcnt, blk;
 817         u32 size;
 818         struct buffer_head *ext_bh;
 819         int i;
 820
 821         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 822                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 823
 824         last_blk = 0;
 825         ext = 0;
 826         if (inode->i_size) {
 827                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 828                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 829         }
 830
 831         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 832                 struct address_space *mapping = inode->i_mapping;
 833                 struct page *page;
 834                 void *fsdata;
 835                 u32 size = inode->i_size;
 836                 int res;
 837
 838                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 839                 if (!res)
 840                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 841                 else
 842                         inode->i_size = AFFS_I(inode)->mmu_private;
 843                 mark_inode_dirty(inode);
 844                 return;
 845         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 846                 return;
 847
 848         // lock cache
 849         ext_bh = affs_get_extblock(inode, ext);
 850         if (IS_ERR(ext_bh)) {
 851                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 852                              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", "unexpected read error for last block %u (%d)",
 899                                              ext, PTR_ERR(bh));
 900                                 return;
 901                         }
 902                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 903                         AFFS_DATA_HEAD(bh)->next = 0;
 904                         affs_adjust_checksum(bh, -tmp);
 905                         affs_brelse(bh);
 906                 }
 907         } else {
 908                 AFFS_I(inode)->i_blkcnt = 0;
 909                 AFFS_I(inode)->i_extcnt = 1;
 910         }
 911         AFFS_I(inode)->mmu_private = inode->i_size;
 912         // unlock cache
 913
 914         while (ext_key) {
 915                 ext_bh = affs_bread(sb, ext_key);
 916                 size = AFFS_SB(sb)->s_hashsize;
 917                 if (size > blkcnt - blk)
 918                         size = blkcnt - blk;
 919                 for (i = 0; i < size; i++, blk++)
 920                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 921                 affs_free_block(sb, ext_key);
 922                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 923                 affs_brelse(ext_bh);
 924         }
 925         affs_free_prealloc(inode);
 926 }
 927
 928 int affs_file_fsync(struct file *filp, int datasync)
 929 {
 930         struct inode *inode = filp->f_mapping->host;
 931         int ret, err;
 932
 933         ret = write_inode_now(inode, 0);
 934         err = sync_blockdev(inode->i_sb->s_bdev);
 935         if (!ret)
 936                 ret = err;
 937         return ret;
 938 }