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/uio.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                 inode_lock(inode);
  37                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  38                         affs_truncate(inode);
  39                 affs_free_prealloc(inode);
  40                 inode_unlock(inode);
  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(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 393 {
 394         struct file *file = iocb->ki_filp;
 395         struct address_space *mapping = file->f_mapping;
 396         struct inode *inode = mapping->host;
 397         size_t count = iov_iter_count(iter);
 398         ssize_t ret;
 399
 400         if (iov_iter_rw(iter) == WRITE) {
 401                 loff_t size = offset + count;
 402
 403                 if (AFFS_I(inode)->mmu_private < size)
 404                         return 0;
 405         }
 406
 407         ret = blockdev_direct_IO(iocb, inode, iter, offset, affs_get_block);
 408         if (ret < 0 && iov_iter_rw(iter) == WRITE)
 409                 affs_write_failed(mapping, offset + count);
 410         return ret;
 411 }
 412
 413 static int affs_write_begin(struct file *file, struct address_space *mapping,
 414                         loff_t pos, unsigned len, unsigned flags,
 415                         struct page **pagep, void **fsdata)
 416 {
 417         int ret;
 418
 419         *pagep = NULL;
 420         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 421                                 affs_get_block,
 422                                 &AFFS_I(mapping->host)->mmu_private);
 423         if (unlikely(ret))
 424                 affs_write_failed(mapping, pos + len);
 425
 426         return ret;
 427 }
 428
 429 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 430 {
 431         return generic_block_bmap(mapping,block,affs_get_block);
 432 }
 433
 434 const struct address_space_operations affs_aops = {
 435         .readpage = affs_readpage,
 436         .writepage = affs_writepage,
 437         .write_begin = affs_write_begin,
 438         .write_end = generic_write_end,
 439         .direct_IO = affs_direct_IO,
 440         .bmap = _affs_bmap
 441 };
 442
 443 static inline struct buffer_head *
 444 affs_bread_ino(struct inode *inode, int block, int create)
 445 {
 446         struct buffer_head *bh, tmp_bh;
 447         int err;
 448
 449         tmp_bh.b_state = 0;
 450         err = affs_get_block(inode, block, &tmp_bh, create);
 451         if (!err) {
 452                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 453                 if (bh) {
 454                         bh->b_state |= tmp_bh.b_state;
 455                         return bh;
 456                 }
 457                 err = -EIO;
 458         }
 459         return ERR_PTR(err);
 460 }
 461
 462 static inline struct buffer_head *
 463 affs_getzeroblk_ino(struct inode *inode, int block)
 464 {
 465         struct buffer_head *bh, tmp_bh;
 466         int err;
 467
 468         tmp_bh.b_state = 0;
 469         err = affs_get_block(inode, block, &tmp_bh, 1);
 470         if (!err) {
 471                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 472                 if (bh) {
 473                         bh->b_state |= tmp_bh.b_state;
 474                         return bh;
 475                 }
 476                 err = -EIO;
 477         }
 478         return ERR_PTR(err);
 479 }
 480
 481 static inline struct buffer_head *
 482 affs_getemptyblk_ino(struct inode *inode, int block)
 483 {
 484         struct buffer_head *bh, tmp_bh;
 485         int err;
 486
 487         tmp_bh.b_state = 0;
 488         err = affs_get_block(inode, block, &tmp_bh, 1);
 489         if (!err) {
 490                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 491                 if (bh) {
 492                         bh->b_state |= tmp_bh.b_state;
 493                         return bh;
 494                 }
 495                 err = -EIO;
 496         }
 497         return ERR_PTR(err);
 498 }
 499
 500 static int
 501 affs_do_readpage_ofs(struct page *page, unsigned to)
 502 {
 503         struct inode *inode = page->mapping->host;
 504         struct super_block *sb = inode->i_sb;
 505         struct buffer_head *bh;
 506         char *data;
 507         unsigned pos = 0;
 508         u32 bidx, boff, bsize;
 509         u32 tmp;
 510
 511         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 512                  page->index, to);
 513         BUG_ON(to > PAGE_CACHE_SIZE);
 514         bsize = AFFS_SB(sb)->s_data_blksize;
 515         tmp = page->index << PAGE_CACHE_SHIFT;
 516         bidx = tmp / bsize;
 517         boff = tmp % bsize;
 518
 519         while (pos < to) {
 520                 bh = affs_bread_ino(inode, bidx, 0);
 521                 if (IS_ERR(bh))
 522                         return PTR_ERR(bh);
 523                 tmp = min(bsize - boff, to - pos);
 524                 BUG_ON(pos + tmp > to || tmp > bsize);
 525                 data = kmap_atomic(page);
 526                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 527                 kunmap_atomic(data);
 528                 affs_brelse(bh);
 529                 bidx++;
 530                 pos += tmp;
 531                 boff = 0;
 532         }
 533         flush_dcache_page(page);
 534         return 0;
 535 }
 536
 537 static int
 538 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 539 {
 540         struct super_block *sb = inode->i_sb;
 541         struct buffer_head *bh, *prev_bh;
 542         u32 bidx, boff;
 543         u32 size, bsize;
 544         u32 tmp;
 545
 546         pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 547         bsize = AFFS_SB(sb)->s_data_blksize;
 548         bh = NULL;
 549         size = AFFS_I(inode)->mmu_private;
 550         bidx = size / bsize;
 551         boff = size % bsize;
 552         if (boff) {
 553                 bh = affs_bread_ino(inode, bidx, 0);
 554                 if (IS_ERR(bh))
 555                         return PTR_ERR(bh);
 556                 tmp = min(bsize - boff, newsize - size);
 557                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 558                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 559                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 560                 affs_fix_checksum(sb, bh);
 561                 mark_buffer_dirty_inode(bh, inode);
 562                 size += tmp;
 563                 bidx++;
 564         } else if (bidx) {
 565                 bh = affs_bread_ino(inode, bidx - 1, 0);
 566                 if (IS_ERR(bh))
 567                         return PTR_ERR(bh);
 568         }
 569
 570         while (size < newsize) {
 571                 prev_bh = bh;
 572                 bh = affs_getzeroblk_ino(inode, bidx);
 573                 if (IS_ERR(bh))
 574                         goto out;
 575                 tmp = min(bsize, newsize - size);
 576                 BUG_ON(tmp > bsize);
 577                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 578                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 579                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 580                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 581                 affs_fix_checksum(sb, bh);
 582                 bh->b_state &= ~(1UL << BH_New);
 583                 mark_buffer_dirty_inode(bh, inode);
 584                 if (prev_bh) {
 585                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 586
 587                         if (tmp_next)
 588                                 affs_warning(sb, "extent_file_ofs",
 589                                              "next block already set for %d (%d)",
 590                                              bidx, tmp_next);
 591                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 592                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 593                         mark_buffer_dirty_inode(prev_bh, inode);
 594                         affs_brelse(prev_bh);
 595                 }
 596                 size += bsize;
 597                 bidx++;
 598         }
 599         affs_brelse(bh);
 600         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 601         return 0;
 602
 603 out:
 604         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 605         return PTR_ERR(bh);
 606 }
 607
 608 static int
 609 affs_readpage_ofs(struct file *file, struct page *page)
 610 {
 611         struct inode *inode = page->mapping->host;
 612         u32 to;
 613         int err;
 614
 615         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 616         to = PAGE_CACHE_SIZE;
 617         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 618                 to = inode->i_size & ~PAGE_CACHE_MASK;
 619                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 620         }
 621
 622         err = affs_do_readpage_ofs(page, to);
 623         if (!err)
 624                 SetPageUptodate(page);
 625         unlock_page(page);
 626         return err;
 627 }
 628
 629 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 630                                 loff_t pos, unsigned len, unsigned flags,
 631                                 struct page **pagep, void **fsdata)
 632 {
 633         struct inode *inode = mapping->host;
 634         struct page *page;
 635         pgoff_t index;
 636         int err = 0;
 637
 638         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 639                  pos + len);
 640         if (pos > AFFS_I(inode)->mmu_private) {
 641                 /* XXX: this probably leaves a too-big i_size in case of
 642                  * failure. Should really be updating i_size at write_end time
 643                  */
 644                 err = affs_extent_file_ofs(inode, pos);
 645                 if (err)
 646                         return err;
 647         }
 648
 649         index = pos >> PAGE_CACHE_SHIFT;
 650         page = grab_cache_page_write_begin(mapping, index, flags);
 651         if (!page)
 652                 return -ENOMEM;
 653         *pagep = page;
 654
 655         if (PageUptodate(page))
 656                 return 0;
 657
 658         /* XXX: inefficient but safe in the face of short writes */
 659         err = affs_do_readpage_ofs(page, PAGE_CACHE_SIZE);
 660         if (err) {
 661                 unlock_page(page);
 662                 page_cache_release(page);
 663         }
 664         return err;
 665 }
 666
 667 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 668                                 loff_t pos, unsigned len, unsigned copied,
 669                                 struct page *page, void *fsdata)
 670 {
 671         struct inode *inode = mapping->host;
 672         struct super_block *sb = inode->i_sb;
 673         struct buffer_head *bh, *prev_bh;
 674         char *data;
 675         u32 bidx, boff, bsize;
 676         unsigned from, to;
 677         u32 tmp;
 678         int written;
 679
 680         from = pos & (PAGE_CACHE_SIZE - 1);
 681         to = pos + len;
 682         /*
 683          * XXX: not sure if this can handle short copies (len < copied), but
 684          * we don't have to, because the page should always be uptodate here,
 685          * due to write_begin.
 686          */
 687
 688         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 689                  pos + len);
 690         bsize = AFFS_SB(sb)->s_data_blksize;
 691         data = page_address(page);
 692
 693         bh = NULL;
 694         written = 0;
 695         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 696         bidx = tmp / bsize;
 697         boff = tmp % bsize;
 698         if (boff) {
 699                 bh = affs_bread_ino(inode, bidx, 0);
 700                 if (IS_ERR(bh)) {
 701                         written = PTR_ERR(bh);
 702                         goto err_first_bh;
 703                 }
 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                         written = PTR_ERR(bh);
 717                         goto err_first_bh;
 718                 }
 719         }
 720         while (from + bsize <= to) {
 721                 prev_bh = bh;
 722                 bh = affs_getemptyblk_ino(inode, bidx);
 723                 if (IS_ERR(bh))
 724                         goto err_bh;
 725                 memcpy(AFFS_DATA(bh), data + from, bsize);
 726                 if (buffer_new(bh)) {
 727                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 728                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 729                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 730                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 731                         AFFS_DATA_HEAD(bh)->next = 0;
 732                         bh->b_state &= ~(1UL << BH_New);
 733                         if (prev_bh) {
 734                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 735
 736                                 if (tmp_next)
 737                                         affs_warning(sb, "commit_write_ofs",
 738                                                      "next block already set for %d (%d)",
 739                                                      bidx, tmp_next);
 740                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 741                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 742                                 mark_buffer_dirty_inode(prev_bh, inode);
 743                         }
 744                 }
 745                 affs_brelse(prev_bh);
 746                 affs_fix_checksum(sb, bh);
 747                 mark_buffer_dirty_inode(bh, inode);
 748                 written += bsize;
 749                 from += bsize;
 750                 bidx++;
 751         }
 752         if (from < to) {
 753                 prev_bh = bh;
 754                 bh = affs_bread_ino(inode, bidx, 1);
 755                 if (IS_ERR(bh))
 756                         goto err_bh;
 757                 tmp = min(bsize, to - from);
 758                 BUG_ON(tmp > bsize);
 759                 memcpy(AFFS_DATA(bh), data + from, tmp);
 760                 if (buffer_new(bh)) {
 761                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 762                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 763                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 764                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 765                         AFFS_DATA_HEAD(bh)->next = 0;
 766                         bh->b_state &= ~(1UL << BH_New);
 767                         if (prev_bh) {
 768                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 769
 770                                 if (tmp_next)
 771                                         affs_warning(sb, "commit_write_ofs",
 772                                                      "next block already set for %d (%d)",
 773                                                      bidx, tmp_next);
 774                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 775                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 776                                 mark_buffer_dirty_inode(prev_bh, inode);
 777                         }
 778                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 779                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 780                 affs_brelse(prev_bh);
 781                 affs_fix_checksum(sb, bh);
 782                 mark_buffer_dirty_inode(bh, inode);
 783                 written += tmp;
 784                 from += tmp;
 785                 bidx++;
 786         }
 787         SetPageUptodate(page);
 788
 789 done:
 790         affs_brelse(bh);
 791         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 792         if (tmp > inode->i_size)
 793                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 794
 795 err_first_bh:
 796         unlock_page(page);
 797         page_cache_release(page);
 798
 799         return written;
 800
 801 err_bh:
 802         bh = prev_bh;
 803         if (!written)
 804                 written = PTR_ERR(bh);
 805         goto done;
 806 }
 807
 808 const struct address_space_operations affs_aops_ofs = {
 809         .readpage = affs_readpage_ofs,
 810         //.writepage = affs_writepage_ofs,
 811         .write_begin = affs_write_begin_ofs,
 812         .write_end = affs_write_end_ofs
 813 };
 814
 815 /* Free any preallocated blocks. */
 816
 817 void
 818 affs_free_prealloc(struct inode *inode)
 819 {
 820         struct super_block *sb = inode->i_sb;
 821
 822         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 823
 824         while (AFFS_I(inode)->i_pa_cnt) {
 825                 AFFS_I(inode)->i_pa_cnt--;
 826                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 827         }
 828 }
 829
 830 /* Truncate (or enlarge) a file to the requested size. */
 831
 832 void
 833 affs_truncate(struct inode *inode)
 834 {
 835         struct super_block *sb = inode->i_sb;
 836         u32 ext, ext_key;
 837         u32 last_blk, blkcnt, blk;
 838         u32 size;
 839         struct buffer_head *ext_bh;
 840         int i;
 841
 842         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 843                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 844
 845         last_blk = 0;
 846         ext = 0;
 847         if (inode->i_size) {
 848                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 849                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 850         }
 851
 852         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 853                 struct address_space *mapping = inode->i_mapping;
 854                 struct page *page;
 855                 void *fsdata;
 856                 loff_t isize = inode->i_size;
 857                 int res;
 858
 859                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 860                 if (!res)
 861                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 862                 else
 863                         inode->i_size = AFFS_I(inode)->mmu_private;
 864                 mark_inode_dirty(inode);
 865                 return;
 866         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 867                 return;
 868
 869         // lock cache
 870         ext_bh = affs_get_extblock(inode, ext);
 871         if (IS_ERR(ext_bh)) {
 872                 affs_warning(sb, "truncate",
 873                              "unexpected read error for ext block %u (%ld)",
 874                              ext, PTR_ERR(ext_bh));
 875                 return;
 876         }
 877         if (AFFS_I(inode)->i_lc) {
 878                 /* clear linear cache */
 879                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 880                 if (AFFS_I(inode)->i_lc_size > i) {
 881                         AFFS_I(inode)->i_lc_size = i;
 882                         for (; i < AFFS_LC_SIZE; i++)
 883                                 AFFS_I(inode)->i_lc[i] = 0;
 884                 }
 885                 /* clear associative cache */
 886                 for (i = 0; i < AFFS_AC_SIZE; i++)
 887                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 888                                 AFFS_I(inode)->i_ac[i].ext = 0;
 889         }
 890         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 891
 892         blkcnt = AFFS_I(inode)->i_blkcnt;
 893         i = 0;
 894         blk = last_blk;
 895         if (inode->i_size) {
 896                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 897                 blk++;
 898         } else
 899                 AFFS_HEAD(ext_bh)->first_data = 0;
 900         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 901         size = AFFS_SB(sb)->s_hashsize;
 902         if (size > blkcnt - blk + i)
 903                 size = blkcnt - blk + i;
 904         for (; i < size; i++, blk++) {
 905                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 906                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 907         }
 908         AFFS_TAIL(sb, ext_bh)->extension = 0;
 909         affs_fix_checksum(sb, ext_bh);
 910         mark_buffer_dirty_inode(ext_bh, inode);
 911         affs_brelse(ext_bh);
 912
 913         if (inode->i_size) {
 914                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 915                 AFFS_I(inode)->i_extcnt = ext + 1;
 916                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 917                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 918                         u32 tmp;
 919                         if (IS_ERR(bh)) {
 920                                 affs_warning(sb, "truncate",
 921                                              "unexpected read error for last block %u (%ld)",
 922                                              ext, PTR_ERR(bh));
 923                                 return;
 924                         }
 925                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 926                         AFFS_DATA_HEAD(bh)->next = 0;
 927                         affs_adjust_checksum(bh, -tmp);
 928                         affs_brelse(bh);
 929                 }
 930         } else {
 931                 AFFS_I(inode)->i_blkcnt = 0;
 932                 AFFS_I(inode)->i_extcnt = 1;
 933         }
 934         AFFS_I(inode)->mmu_private = inode->i_size;
 935         // unlock cache
 936
 937         while (ext_key) {
 938                 ext_bh = affs_bread(sb, ext_key);
 939                 size = AFFS_SB(sb)->s_hashsize;
 940                 if (size > blkcnt - blk)
 941                         size = blkcnt - blk;
 942                 for (i = 0; i < size; i++, blk++)
 943                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 944                 affs_free_block(sb, ext_key);
 945                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 946                 affs_brelse(ext_bh);
 947         }
 948         affs_free_prealloc(inode);
 949 }
 950
 951 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 952 {
 953         struct inode *inode = filp->f_mapping->host;
 954         int ret, err;
 955
 956         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 957         if (err)
 958                 return err;
 959
 960         inode_lock(inode);
 961         ret = write_inode_now(inode, 0);
 962         err = sync_blockdev(inode->i_sb->s_bdev);
 963         if (!ret)
 964                 ret = err;
 965         inode_unlock(inode);
 966         return ret;
 967 }
 968 const struct file_operations affs_file_operations = {
 969         .llseek         = generic_file_llseek,
 970         .read_iter      = generic_file_read_iter,
 971         .write_iter     = generic_file_write_iter,
 972         .mmap           = generic_file_mmap,
 973         .open           = affs_file_open,
 974         .release        = affs_file_release,
 975         .fsync          = affs_file_fsync,
 976         .splice_read    = generic_file_splice_read,
 977 };
 978
 979 const struct inode_operations affs_file_inode_operations = {
 980         .setattr        = affs_notify_change,
 981 };