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 <linux/aio.h>
  16 #include "affs.h"
  17
  18 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  19
  20 static int
  21 affs_file_open(struct inode *inode, struct file *filp)
  22 {
  23         pr_debug("open(%lu,%d)\n",
  24                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  25         atomic_inc(&AFFS_I(inode)->i_opencnt);
  26         return 0;
  27 }
  28
  29 static int
  30 affs_file_release(struct inode *inode, struct file *filp)
  31 {
  32         pr_debug("release(%lu, %d)\n",
  33                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  34
  35         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  36                 mutex_lock(&inode->i_mutex);
  37                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  38                         affs_truncate(inode);
  39                 affs_free_prealloc(inode);
  40                 mutex_unlock(&inode->i_mutex);
  41         }
  42
  43         return 0;
  44 }
  45
  46 static int
  47 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  48 {
  49         struct super_block      *sb = inode->i_sb;
  50         struct buffer_head      *bh;
  51         u32 lc_max;
  52         int i, j, key;
  53
  54         if (!AFFS_I(inode)->i_lc) {
  55                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  56                 if (!ptr)
  57                         return -ENOMEM;
  58                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  59                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  60         }
  61
  62         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  63
  64         if (AFFS_I(inode)->i_extcnt > lc_max) {
  65                 u32 lc_shift, lc_mask, tmp, off;
  66
  67                 /* need to recalculate linear cache, start from old size */
  68                 lc_shift = AFFS_I(inode)->i_lc_shift;
  69                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  70                 for (; tmp; tmp >>= 1)
  71                         lc_shift++;
  72                 lc_mask = (1 << lc_shift) - 1;
  73
  74                 /* fix idx and old size to new shift */
  75                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  76                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  77
  78                 /* first shrink old cache to make more space */
  79                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  80                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  81                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  82
  83                 AFFS_I(inode)->i_lc_shift = lc_shift;
  84                 AFFS_I(inode)->i_lc_mask = lc_mask;
  85         }
  86
  87         /* fill cache to the needed index */
  88         i = AFFS_I(inode)->i_lc_size;
  89         AFFS_I(inode)->i_lc_size = lc_idx + 1;
  90         for (; i <= lc_idx; i++) {
  91                 if (!i) {
  92                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
  93                         continue;
  94                 }
  95                 key = AFFS_I(inode)->i_lc[i - 1];
  96                 j = AFFS_I(inode)->i_lc_mask + 1;
  97                 // unlock cache
  98                 for (; j > 0; j--) {
  99                         bh = affs_bread(sb, key);
 100                         if (!bh)
 101                                 goto err;
 102                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 103                         affs_brelse(bh);
 104                 }
 105                 // lock cache
 106                 AFFS_I(inode)->i_lc[i] = key;
 107         }
 108
 109         return 0;
 110
 111 err:
 112         // lock cache
 113         return -EIO;
 114 }
 115
 116 static struct buffer_head *
 117 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 118 {
 119         struct super_block *sb = inode->i_sb;
 120         struct buffer_head *new_bh;
 121         u32 blocknr, tmp;
 122
 123         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 124         if (!blocknr)
 125                 return ERR_PTR(-ENOSPC);
 126
 127         new_bh = affs_getzeroblk(sb, blocknr);
 128         if (!new_bh) {
 129                 affs_free_block(sb, blocknr);
 130                 return ERR_PTR(-EIO);
 131         }
 132
 133         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 134         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 135         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 136         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 137         affs_fix_checksum(sb, new_bh);
 138
 139         mark_buffer_dirty_inode(new_bh, inode);
 140
 141         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 142         if (tmp)
 143                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 144         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 145         affs_adjust_checksum(bh, blocknr - tmp);
 146         mark_buffer_dirty_inode(bh, inode);
 147
 148         AFFS_I(inode)->i_extcnt++;
 149         mark_inode_dirty(inode);
 150
 151         return new_bh;
 152 }
 153
 154 static inline struct buffer_head *
 155 affs_get_extblock(struct inode *inode, u32 ext)
 156 {
 157         /* inline the simplest case: same extended block as last time */
 158         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 159         if (ext == AFFS_I(inode)->i_ext_last)
 160                 get_bh(bh);
 161         else
 162                 /* we have to do more (not inlined) */
 163                 bh = affs_get_extblock_slow(inode, ext);
 164
 165         return bh;
 166 }
 167
 168 static struct buffer_head *
 169 affs_get_extblock_slow(struct inode *inode, u32 ext)
 170 {
 171         struct super_block *sb = inode->i_sb;
 172         struct buffer_head *bh;
 173         u32 ext_key;
 174         u32 lc_idx, lc_off, ac_idx;
 175         u32 tmp, idx;
 176
 177         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 178                 /* read the next extended block from the current one */
 179                 bh = AFFS_I(inode)->i_ext_bh;
 180                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 181                 if (ext < AFFS_I(inode)->i_extcnt)
 182                         goto read_ext;
 183                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 184                 bh = affs_alloc_extblock(inode, bh, ext);
 185                 if (IS_ERR(bh))
 186                         return bh;
 187                 goto store_ext;
 188         }
 189
 190         if (ext == 0) {
 191                 /* we seek back to the file header block */
 192                 ext_key = inode->i_ino;
 193                 goto read_ext;
 194         }
 195
 196         if (ext >= AFFS_I(inode)->i_extcnt) {
 197                 struct buffer_head *prev_bh;
 198
 199                 /* allocate a new extended block */
 200                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 201
 202                 /* get previous extended block */
 203                 prev_bh = affs_get_extblock(inode, ext - 1);
 204                 if (IS_ERR(prev_bh))
 205                         return prev_bh;
 206                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 207                 affs_brelse(prev_bh);
 208                 if (IS_ERR(bh))
 209                         return bh;
 210                 goto store_ext;
 211         }
 212
 213 again:
 214         /* check if there is an extended cache and whether it's large enough */
 215         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 216         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 217
 218         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 219                 int err;
 220
 221                 err = affs_grow_extcache(inode, lc_idx);
 222                 if (err)
 223                         return ERR_PTR(err);
 224                 goto again;
 225         }
 226
 227         /* every n'th key we find in the linear cache */
 228         if (!lc_off) {
 229                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 230                 goto read_ext;
 231         }
 232
 233         /* maybe it's still in the associative cache */
 234         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 235         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 236                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 237                 goto read_ext;
 238         }
 239
 240         /* try to find one of the previous extended blocks */
 241         tmp = ext;
 242         idx = ac_idx;
 243         while (--tmp, --lc_off > 0) {
 244                 idx = (idx - 1) & AFFS_AC_MASK;
 245                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 246                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 247                         goto find_ext;
 248                 }
 249         }
 250
 251         /* fall back to the linear cache */
 252         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 253 find_ext:
 254         /* read all extended blocks until we find the one we need */
 255         //unlock cache
 256         do {
 257                 bh = affs_bread(sb, ext_key);
 258                 if (!bh)
 259                         goto err_bread;
 260                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 261                 affs_brelse(bh);
 262                 tmp++;
 263         } while (tmp < ext);
 264         //lock cache
 265
 266         /* store it in the associative cache */
 267         // recalculate ac_idx?
 268         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 269         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 270
 271 read_ext:
 272         /* finally read the right extended block */
 273         //unlock cache
 274         bh = affs_bread(sb, ext_key);
 275         if (!bh)
 276                 goto err_bread;
 277         //lock cache
 278
 279 store_ext:
 280         /* release old cached extended block and store the new one */
 281         affs_brelse(AFFS_I(inode)->i_ext_bh);
 282         AFFS_I(inode)->i_ext_last = ext;
 283         AFFS_I(inode)->i_ext_bh = bh;
 284         get_bh(bh);
 285
 286         return bh;
 287
 288 err_bread:
 289         affs_brelse(bh);
 290         return ERR_PTR(-EIO);
 291 }
 292
 293 static int
 294 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 295 {
 296         struct super_block      *sb = inode->i_sb;
 297         struct buffer_head      *ext_bh;
 298         u32                      ext;
 299
 300         pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 301                  (unsigned long long)block);
 302
 303         BUG_ON(block > (sector_t)0x7fffffffUL);
 304
 305         if (block >= AFFS_I(inode)->i_blkcnt) {
 306                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 307                         goto err_big;
 308         } else
 309                 create = 0;
 310
 311         //lock cache
 312         affs_lock_ext(inode);
 313
 314         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 315         block -= ext * AFFS_SB(sb)->s_hashsize;
 316         ext_bh = affs_get_extblock(inode, ext);
 317         if (IS_ERR(ext_bh))
 318                 goto err_ext;
 319         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 320
 321         if (create) {
 322                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 323                 if (!blocknr)
 324                         goto err_alloc;
 325                 set_buffer_new(bh_result);
 326                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 327                 AFFS_I(inode)->i_blkcnt++;
 328
 329                 /* store new block */
 330                 if (bh_result->b_blocknr)
 331                         affs_warning(sb, "get_block",
 332                                      "block already set (%llx)",
 333                                      (unsigned long long)bh_result->b_blocknr);
 334                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 335                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 336                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 337                 bh_result->b_blocknr = blocknr;
 338
 339                 if (!block) {
 340                         /* insert first block into header block */
 341                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 342                         if (tmp)
 343                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 344                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 345                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 346                 }
 347         }
 348
 349         affs_brelse(ext_bh);
 350         //unlock cache
 351         affs_unlock_ext(inode);
 352         return 0;
 353
 354 err_big:
 355         affs_error(inode->i_sb, "get_block", "strange block request %llu",
 356                    (unsigned long long)block);
 357         return -EIO;
 358 err_ext:
 359         // unlock cache
 360         affs_unlock_ext(inode);
 361         return PTR_ERR(ext_bh);
 362 err_alloc:
 363         brelse(ext_bh);
 364         clear_buffer_mapped(bh_result);
 365         bh_result->b_bdev = NULL;
 366         // unlock cache
 367         affs_unlock_ext(inode);
 368         return -ENOSPC;
 369 }
 370
 371 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 372 {
 373         return block_write_full_page(page, affs_get_block, wbc);
 374 }
 375
 376 static int affs_readpage(struct file *file, struct page *page)
 377 {
 378         return block_read_full_page(page, affs_get_block);
 379 }
 380
 381 static void affs_write_failed(struct address_space *mapping, loff_t to)
 382 {
 383         struct inode *inode = mapping->host;
 384
 385         if (to > inode->i_size) {
 386                 truncate_pagecache(inode, inode->i_size);
 387                 affs_truncate(inode);
 388         }
 389 }
 390
 391 static ssize_t
 392 affs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 393                loff_t offset)
 394 {
 395         struct file *file = iocb->ki_filp;
 396         struct address_space *mapping = file->f_mapping;
 397         struct inode *inode = mapping->host;
 398         size_t count = iov_iter_count(iter);
 399         ssize_t ret;
 400
 401         if (rw == WRITE) {
 402                 loff_t size = offset + count;
 403
 404                 if (AFFS_I(inode)->mmu_private < size)
 405                         return 0;
 406         }
 407
 408         ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, affs_get_block);
 409         if (ret < 0 && (rw & WRITE))
 410                 affs_write_failed(mapping, offset + count);
 411         return ret;
 412 }
 413
 414 static int affs_write_begin(struct file *file, struct address_space *mapping,
 415                         loff_t pos, unsigned len, unsigned flags,
 416                         struct page **pagep, void **fsdata)
 417 {
 418         int ret;
 419
 420         *pagep = NULL;
 421         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 422                                 affs_get_block,
 423                                 &AFFS_I(mapping->host)->mmu_private);
 424         if (unlikely(ret))
 425                 affs_write_failed(mapping, pos + len);
 426
 427         return ret;
 428 }
 429
 430 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 431 {
 432         return generic_block_bmap(mapping,block,affs_get_block);
 433 }
 434
 435 const struct address_space_operations affs_aops = {
 436         .readpage = affs_readpage,
 437         .writepage = affs_writepage,
 438         .write_begin = affs_write_begin,
 439         .write_end = generic_write_end,
 440         .direct_IO = affs_direct_IO,
 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(%lu, %ld, 0, %d)\n", __func__, 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(%lu, %d)\n", __func__, 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(%lu, %ld)\n", __func__, 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(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 641                  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(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 691                  pos + len);
 692         bsize = AFFS_SB(sb)->s_data_blksize;
 693         data = page_address(page);
 694
 695         bh = NULL;
 696         written = 0;
 697         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 698         bidx = tmp / bsize;
 699         boff = tmp % bsize;
 700         if (boff) {
 701                 bh = affs_bread_ino(inode, bidx, 0);
 702                 if (IS_ERR(bh))
 703                         return PTR_ERR(bh);
 704                 tmp = min(bsize - boff, to - from);
 705                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 706                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 707                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 708                 affs_fix_checksum(sb, bh);
 709                 mark_buffer_dirty_inode(bh, inode);
 710                 written += tmp;
 711                 from += tmp;
 712                 bidx++;
 713         } else if (bidx) {
 714                 bh = affs_bread_ino(inode, bidx - 1, 0);
 715                 if (IS_ERR(bh))
 716                         return PTR_ERR(bh);
 717         }
 718         while (from + bsize <= to) {
 719                 prev_bh = bh;
 720                 bh = affs_getemptyblk_ino(inode, bidx);
 721                 if (IS_ERR(bh))
 722                         goto out;
 723                 memcpy(AFFS_DATA(bh), data + from, bsize);
 724                 if (buffer_new(bh)) {
 725                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 726                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 727                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 728                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 729                         AFFS_DATA_HEAD(bh)->next = 0;
 730                         bh->b_state &= ~(1UL << BH_New);
 731                         if (prev_bh) {
 732                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 733
 734                                 if (tmp_next)
 735                                         affs_warning(sb, "commit_write_ofs",
 736                                                      "next block already set for %d (%d)",
 737                                                      bidx, tmp_next);
 738                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 739                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 740                                 mark_buffer_dirty_inode(prev_bh, inode);
 741                         }
 742                 }
 743                 affs_brelse(prev_bh);
 744                 affs_fix_checksum(sb, bh);
 745                 mark_buffer_dirty_inode(bh, inode);
 746                 written += bsize;
 747                 from += bsize;
 748                 bidx++;
 749         }
 750         if (from < to) {
 751                 prev_bh = bh;
 752                 bh = affs_bread_ino(inode, bidx, 1);
 753                 if (IS_ERR(bh))
 754                         goto out;
 755                 tmp = min(bsize, to - from);
 756                 BUG_ON(tmp > bsize);
 757                 memcpy(AFFS_DATA(bh), data + from, tmp);
 758                 if (buffer_new(bh)) {
 759                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 760                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 761                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 762                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 763                         AFFS_DATA_HEAD(bh)->next = 0;
 764                         bh->b_state &= ~(1UL << BH_New);
 765                         if (prev_bh) {
 766                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 767
 768                                 if (tmp_next)
 769                                         affs_warning(sb, "commit_write_ofs",
 770                                                      "next block already set for %d (%d)",
 771                                                      bidx, tmp_next);
 772                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 773                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 774                                 mark_buffer_dirty_inode(prev_bh, inode);
 775                         }
 776                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 777                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 778                 affs_brelse(prev_bh);
 779                 affs_fix_checksum(sb, bh);
 780                 mark_buffer_dirty_inode(bh, inode);
 781                 written += tmp;
 782                 from += tmp;
 783                 bidx++;
 784         }
 785         SetPageUptodate(page);
 786
 787 done:
 788         affs_brelse(bh);
 789         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 790         if (tmp > inode->i_size)
 791                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 792
 793         unlock_page(page);
 794         page_cache_release(page);
 795
 796         return written;
 797
 798 out:
 799         bh = prev_bh;
 800         if (!written)
 801                 written = PTR_ERR(bh);
 802         goto done;
 803 }
 804
 805 const struct address_space_operations affs_aops_ofs = {
 806         .readpage = affs_readpage_ofs,
 807         //.writepage = affs_writepage_ofs,
 808         .write_begin = affs_write_begin_ofs,
 809         .write_end = affs_write_end_ofs
 810 };
 811
 812 /* Free any preallocated blocks. */
 813
 814 void
 815 affs_free_prealloc(struct inode *inode)
 816 {
 817         struct super_block *sb = inode->i_sb;
 818
 819         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 820
 821         while (AFFS_I(inode)->i_pa_cnt) {
 822                 AFFS_I(inode)->i_pa_cnt--;
 823                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 824         }
 825 }
 826
 827 /* Truncate (or enlarge) a file to the requested size. */
 828
 829 void
 830 affs_truncate(struct inode *inode)
 831 {
 832         struct super_block *sb = inode->i_sb;
 833         u32 ext, ext_key;
 834         u32 last_blk, blkcnt, blk;
 835         u32 size;
 836         struct buffer_head *ext_bh;
 837         int i;
 838
 839         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 840                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 841
 842         last_blk = 0;
 843         ext = 0;
 844         if (inode->i_size) {
 845                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 846                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 847         }
 848
 849         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 850                 struct address_space *mapping = inode->i_mapping;
 851                 struct page *page;
 852                 void *fsdata;
 853                 loff_t isize = inode->i_size;
 854                 int res;
 855
 856                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 857                 if (!res)
 858                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 859                 else
 860                         inode->i_size = AFFS_I(inode)->mmu_private;
 861                 mark_inode_dirty(inode);
 862                 return;
 863         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 864                 return;
 865
 866         // lock cache
 867         ext_bh = affs_get_extblock(inode, ext);
 868         if (IS_ERR(ext_bh)) {
 869                 affs_warning(sb, "truncate",
 870                              "unexpected read error for ext block %u (%ld)",
 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",
 918                                              "unexpected read error for last block %u (%ld)",
 919                                              ext, PTR_ERR(bh));
 920                                 return;
 921                         }
 922                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 923                         AFFS_DATA_HEAD(bh)->next = 0;
 924                         affs_adjust_checksum(bh, -tmp);
 925                         affs_brelse(bh);
 926                 }
 927         } else {
 928                 AFFS_I(inode)->i_blkcnt = 0;
 929                 AFFS_I(inode)->i_extcnt = 1;
 930         }
 931         AFFS_I(inode)->mmu_private = inode->i_size;
 932         // unlock cache
 933
 934         while (ext_key) {
 935                 ext_bh = affs_bread(sb, ext_key);
 936                 size = AFFS_SB(sb)->s_hashsize;
 937                 if (size > blkcnt - blk)
 938                         size = blkcnt - blk;
 939                 for (i = 0; i < size; i++, blk++)
 940                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 941                 affs_free_block(sb, ext_key);
 942                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 943                 affs_brelse(ext_bh);
 944         }
 945         affs_free_prealloc(inode);
 946 }
 947
 948 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 949 {
 950         struct inode *inode = filp->f_mapping->host;
 951         int ret, err;
 952
 953         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 954         if (err)
 955                 return err;
 956
 957         mutex_lock(&inode->i_mutex);
 958         ret = write_inode_now(inode, 0);
 959         err = sync_blockdev(inode->i_sb->s_bdev);
 960         if (!ret)
 961                 ret = err;
 962         mutex_unlock(&inode->i_mutex);
 963         return ret;
 964 }
 965 const struct file_operations affs_file_operations = {
 966         .llseek         = generic_file_llseek,
 967         .read           = new_sync_read,
 968         .read_iter      = generic_file_read_iter,
 969         .write          = new_sync_write,
 970         .write_iter     = generic_file_write_iter,
 971         .mmap           = generic_file_mmap,
 972         .open           = affs_file_open,
 973         .release        = affs_file_release,
 974         .fsync          = affs_file_fsync,
 975         .splice_read    = generic_file_splice_read,
 976 };
 977
 978 const struct inode_operations affs_file_inode_operations = {
 979         .setattr        = affs_notify_change,
 980 };