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                 if (ext > AFFS_I(inode)->i_extcnt)
 184                         BUG();
 185                 bh = affs_alloc_extblock(inode, bh, ext);
 186                 if (IS_ERR(bh))
 187                         return bh;
 188                 goto store_ext;
 189         }
 190
 191         if (ext == 0) {
 192                 /* we seek back to the file header block */
 193                 ext_key = inode->i_ino;
 194                 goto read_ext;
 195         }
 196
 197         if (ext >= AFFS_I(inode)->i_extcnt) {
 198                 struct buffer_head *prev_bh;
 199
 200                 /* allocate a new extended block */
 201                 if (ext > AFFS_I(inode)->i_extcnt)
 202                         BUG();
 203
 204                 /* get previous extended block */
 205                 prev_bh = affs_get_extblock(inode, ext - 1);
 206                 if (IS_ERR(prev_bh))
 207                         return prev_bh;
 208                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 209                 affs_brelse(prev_bh);
 210                 if (IS_ERR(bh))
 211                         return bh;
 212                 goto store_ext;
 213         }
 214
 215 again:
 216         /* check if there is an extended cache and whether it's large enough */
 217         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 218         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 219
 220         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 221                 int err;
 222
 223                 err = affs_grow_extcache(inode, lc_idx);
 224                 if (err)
 225                         return ERR_PTR(err);
 226                 goto again;
 227         }
 228
 229         /* every n'th key we find in the linear cache */
 230         if (!lc_off) {
 231                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 232                 goto read_ext;
 233         }
 234
 235         /* maybe it's still in the associative cache */
 236         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 237         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 238                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 239                 goto read_ext;
 240         }
 241
 242         /* try to find one of the previous extended blocks */
 243         tmp = ext;
 244         idx = ac_idx;
 245         while (--tmp, --lc_off > 0) {
 246                 idx = (idx - 1) & AFFS_AC_MASK;
 247                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 248                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 249                         goto find_ext;
 250                 }
 251         }
 252
 253         /* fall back to the linear cache */
 254         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 255 find_ext:
 256         /* read all extended blocks until we find the one we need */
 257         //unlock cache
 258         do {
 259                 bh = affs_bread(sb, ext_key);
 260                 if (!bh)
 261                         goto err_bread;
 262                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 263                 affs_brelse(bh);
 264                 tmp++;
 265         } while (tmp < ext);
 266         //lock cache
 267
 268         /* store it in the associative cache */
 269         // recalculate ac_idx?
 270         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 271         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 272
 273 read_ext:
 274         /* finally read the right extended block */
 275         //unlock cache
 276         bh = affs_bread(sb, ext_key);
 277         if (!bh)
 278                 goto err_bread;
 279         //lock cache
 280
 281 store_ext:
 282         /* release old cached extended block and store the new one */
 283         affs_brelse(AFFS_I(inode)->i_ext_bh);
 284         AFFS_I(inode)->i_ext_last = ext;
 285         AFFS_I(inode)->i_ext_bh = bh;
 286         get_bh(bh);
 287
 288         return bh;
 289
 290 err_bread:
 291         affs_brelse(bh);
 292         return ERR_PTR(-EIO);
 293 }
 294
 295 static int
 296 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 297 {
 298         struct super_block      *sb = inode->i_sb;
 299         struct buffer_head      *ext_bh;
 300         u32                      ext;
 301
 302         pr_debug("%s(%u, %lu)\n",
 303                  __func__, (u32)inode->i_ino, (unsigned long)block);
 304
 305         BUG_ON(block > (sector_t)0x7fffffffUL);
 306
 307         if (block >= AFFS_I(inode)->i_blkcnt) {
 308                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 309                         goto err_big;
 310         } else
 311                 create = 0;
 312
 313         //lock cache
 314         affs_lock_ext(inode);
 315
 316         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 317         block -= ext * AFFS_SB(sb)->s_hashsize;
 318         ext_bh = affs_get_extblock(inode, ext);
 319         if (IS_ERR(ext_bh))
 320                 goto err_ext;
 321         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 322
 323         if (create) {
 324                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 325                 if (!blocknr)
 326                         goto err_alloc;
 327                 set_buffer_new(bh_result);
 328                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 329                 AFFS_I(inode)->i_blkcnt++;
 330
 331                 /* store new block */
 332                 if (bh_result->b_blocknr)
 333                         affs_warning(sb, "get_block", "block already set (%lx)",
 334                                      (unsigned long)bh_result->b_blocknr);
 335                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 336                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 337                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 338                 bh_result->b_blocknr = blocknr;
 339
 340                 if (!block) {
 341                         /* insert first block into header block */
 342                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 343                         if (tmp)
 344                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 345                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 346                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 347                 }
 348         }
 349
 350         affs_brelse(ext_bh);
 351         //unlock cache
 352         affs_unlock_ext(inode);
 353         return 0;
 354
 355 err_big:
 356         affs_error(inode->i_sb, "get_block", "strange block request %d",
 357                    (int)block);
 358         return -EIO;
 359 err_ext:
 360         // unlock cache
 361         affs_unlock_ext(inode);
 362         return PTR_ERR(ext_bh);
 363 err_alloc:
 364         brelse(ext_bh);
 365         clear_buffer_mapped(bh_result);
 366         bh_result->b_bdev = NULL;
 367         // unlock cache
 368         affs_unlock_ext(inode);
 369         return -ENOSPC;
 370 }
 371
 372 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 373 {
 374         return block_write_full_page(page, affs_get_block, wbc);
 375 }
 376
 377 static int affs_readpage(struct file *file, struct page *page)
 378 {
 379         return block_read_full_page(page, affs_get_block);
 380 }
 381
 382 static void affs_write_failed(struct address_space *mapping, loff_t to)
 383 {
 384         struct inode *inode = mapping->host;
 385
 386         if (to > inode->i_size) {
 387                 truncate_pagecache(inode, inode->i_size);
 388                 affs_truncate(inode);
 389         }
 390 }
 391
 392 static ssize_t
 393 affs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 394                loff_t offset)
 395 {
 396         struct file *file = iocb->ki_filp;
 397         struct address_space *mapping = file->f_mapping;
 398         struct inode *inode = mapping->host;
 399         size_t count = iov_iter_count(iter);
 400         ssize_t ret;
 401
 402         ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, affs_get_block);
 403         if (ret < 0 && (rw & WRITE))
 404                 affs_write_failed(mapping, offset + count);
 405         return ret;
 406 }
 407
 408 static int affs_write_begin(struct file *file, struct address_space *mapping,
 409                         loff_t pos, unsigned len, unsigned flags,
 410                         struct page **pagep, void **fsdata)
 411 {
 412         int ret;
 413
 414         *pagep = NULL;
 415         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 416                                 affs_get_block,
 417                                 &AFFS_I(mapping->host)->mmu_private);
 418         if (unlikely(ret))
 419                 affs_write_failed(mapping, pos + len);
 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         .write_begin = affs_write_begin,
 433         .write_end = generic_write_end,
 434         .direct_IO = affs_direct_IO,
 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 page *page, 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         unsigned pos = 0;
 503         u32 bidx, boff, bsize;
 504         u32 tmp;
 505
 506         pr_debug("%s(%u, %ld, 0, %d)\n", __func__, (u32)inode->i_ino,
 507                  page->index, to);
 508         BUG_ON(to > PAGE_CACHE_SIZE);
 509         kmap(page);
 510         data = page_address(page);
 511         bsize = AFFS_SB(sb)->s_data_blksize;
 512         tmp = page->index << PAGE_CACHE_SHIFT;
 513         bidx = tmp / bsize;
 514         boff = tmp % bsize;
 515
 516         while (pos < to) {
 517                 bh = affs_bread_ino(inode, bidx, 0);
 518                 if (IS_ERR(bh))
 519                         return PTR_ERR(bh);
 520                 tmp = min(bsize - boff, to - pos);
 521                 BUG_ON(pos + tmp > to || tmp > bsize);
 522                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 523                 affs_brelse(bh);
 524                 bidx++;
 525                 pos += tmp;
 526                 boff = 0;
 527         }
 528         flush_dcache_page(page);
 529         kunmap(page);
 530         return 0;
 531 }
 532
 533 static int
 534 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 535 {
 536         struct super_block *sb = inode->i_sb;
 537         struct buffer_head *bh, *prev_bh;
 538         u32 bidx, boff;
 539         u32 size, bsize;
 540         u32 tmp;
 541
 542         pr_debug("%s(%u, %d)\n", __func__, (u32)inode->i_ino, newsize);
 543         bsize = AFFS_SB(sb)->s_data_blksize;
 544         bh = NULL;
 545         size = AFFS_I(inode)->mmu_private;
 546         bidx = size / bsize;
 547         boff = size % bsize;
 548         if (boff) {
 549                 bh = affs_bread_ino(inode, bidx, 0);
 550                 if (IS_ERR(bh))
 551                         return PTR_ERR(bh);
 552                 tmp = min(bsize - boff, newsize - size);
 553                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 554                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 555                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 556                 affs_fix_checksum(sb, bh);
 557                 mark_buffer_dirty_inode(bh, inode);
 558                 size += tmp;
 559                 bidx++;
 560         } else if (bidx) {
 561                 bh = affs_bread_ino(inode, bidx - 1, 0);
 562                 if (IS_ERR(bh))
 563                         return PTR_ERR(bh);
 564         }
 565
 566         while (size < newsize) {
 567                 prev_bh = bh;
 568                 bh = affs_getzeroblk_ino(inode, bidx);
 569                 if (IS_ERR(bh))
 570                         goto out;
 571                 tmp = min(bsize, newsize - size);
 572                 BUG_ON(tmp > bsize);
 573                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 574                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 575                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 576                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 577                 affs_fix_checksum(sb, bh);
 578                 bh->b_state &= ~(1UL << BH_New);
 579                 mark_buffer_dirty_inode(bh, inode);
 580                 if (prev_bh) {
 581                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 582
 583                         if (tmp_next)
 584                                 affs_warning(sb, "extent_file_ofs",
 585                                              "next block already set for %d (%d)",
 586                                              bidx, tmp_next);
 587                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 588                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 589                         mark_buffer_dirty_inode(prev_bh, inode);
 590                         affs_brelse(prev_bh);
 591                 }
 592                 size += bsize;
 593                 bidx++;
 594         }
 595         affs_brelse(bh);
 596         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 597         return 0;
 598
 599 out:
 600         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 601         return PTR_ERR(bh);
 602 }
 603
 604 static int
 605 affs_readpage_ofs(struct file *file, struct page *page)
 606 {
 607         struct inode *inode = page->mapping->host;
 608         u32 to;
 609         int err;
 610
 611         pr_debug("%s(%u, %ld)\n", __func__, (u32)inode->i_ino, page->index);
 612         to = PAGE_CACHE_SIZE;
 613         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 614                 to = inode->i_size & ~PAGE_CACHE_MASK;
 615                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 616         }
 617
 618         err = affs_do_readpage_ofs(page, to);
 619         if (!err)
 620                 SetPageUptodate(page);
 621         unlock_page(page);
 622         return err;
 623 }
 624
 625 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 626                                 loff_t pos, unsigned len, unsigned flags,
 627                                 struct page **pagep, void **fsdata)
 628 {
 629         struct inode *inode = mapping->host;
 630         struct page *page;
 631         pgoff_t index;
 632         int err = 0;
 633
 634         pr_debug("%s(%u, %llu, %llu)\n", __func__, (u32)inode->i_ino,
 635                  (unsigned long long)pos, (unsigned long long)pos + len);
 636         if (pos > AFFS_I(inode)->mmu_private) {
 637                 /* XXX: this probably leaves a too-big i_size in case of
 638                  * failure. Should really be updating i_size at write_end time
 639                  */
 640                 err = affs_extent_file_ofs(inode, pos);
 641                 if (err)
 642                         return err;
 643         }
 644
 645         index = pos >> PAGE_CACHE_SHIFT;
 646         page = grab_cache_page_write_begin(mapping, index, flags);
 647         if (!page)
 648                 return -ENOMEM;
 649         *pagep = page;
 650
 651         if (PageUptodate(page))
 652                 return 0;
 653
 654         /* XXX: inefficient but safe in the face of short writes */
 655         err = affs_do_readpage_ofs(page, PAGE_CACHE_SIZE);
 656         if (err) {
 657                 unlock_page(page);
 658                 page_cache_release(page);
 659         }
 660         return err;
 661 }
 662
 663 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 664                                 loff_t pos, unsigned len, unsigned copied,
 665                                 struct page *page, void *fsdata)
 666 {
 667         struct inode *inode = mapping->host;
 668         struct super_block *sb = inode->i_sb;
 669         struct buffer_head *bh, *prev_bh;
 670         char *data;
 671         u32 bidx, boff, bsize;
 672         unsigned from, to;
 673         u32 tmp;
 674         int written;
 675
 676         from = pos & (PAGE_CACHE_SIZE - 1);
 677         to = pos + len;
 678         /*
 679          * XXX: not sure if this can handle short copies (len < copied), but
 680          * we don't have to, because the page should always be uptodate here,
 681          * due to write_begin.
 682          */
 683
 684         pr_debug("%s(%u, %llu, %llu)\n",
 685                  __func__, (u32)inode->i_ino, (unsigned long long)pos,
 686                 (unsigned long long)pos + len);
 687         bsize = AFFS_SB(sb)->s_data_blksize;
 688         data = page_address(page);
 689
 690         bh = NULL;
 691         written = 0;
 692         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 693         bidx = tmp / bsize;
 694         boff = tmp % bsize;
 695         if (boff) {
 696                 bh = affs_bread_ino(inode, bidx, 0);
 697                 if (IS_ERR(bh))
 698                         return PTR_ERR(bh);
 699                 tmp = min(bsize - boff, to - from);
 700                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 701                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 702                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 703                 affs_fix_checksum(sb, bh);
 704                 mark_buffer_dirty_inode(bh, inode);
 705                 written += tmp;
 706                 from += tmp;
 707                 bidx++;
 708         } else if (bidx) {
 709                 bh = affs_bread_ino(inode, bidx - 1, 0);
 710                 if (IS_ERR(bh))
 711                         return PTR_ERR(bh);
 712         }
 713         while (from + bsize <= to) {
 714                 prev_bh = bh;
 715                 bh = affs_getemptyblk_ino(inode, bidx);
 716                 if (IS_ERR(bh))
 717                         goto out;
 718                 memcpy(AFFS_DATA(bh), data + from, bsize);
 719                 if (buffer_new(bh)) {
 720                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 721                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 722                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 723                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 724                         AFFS_DATA_HEAD(bh)->next = 0;
 725                         bh->b_state &= ~(1UL << BH_New);
 726                         if (prev_bh) {
 727                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 728
 729                                 if (tmp_next)
 730                                         affs_warning(sb, "commit_write_ofs",
 731                                                      "next block already set for %d (%d)",
 732                                                      bidx, tmp_next);
 733                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 734                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 735                                 mark_buffer_dirty_inode(prev_bh, inode);
 736                         }
 737                 }
 738                 affs_brelse(prev_bh);
 739                 affs_fix_checksum(sb, bh);
 740                 mark_buffer_dirty_inode(bh, inode);
 741                 written += bsize;
 742                 from += bsize;
 743                 bidx++;
 744         }
 745         if (from < to) {
 746                 prev_bh = bh;
 747                 bh = affs_bread_ino(inode, bidx, 1);
 748                 if (IS_ERR(bh))
 749                         goto out;
 750                 tmp = min(bsize, to - from);
 751                 BUG_ON(tmp > bsize);
 752                 memcpy(AFFS_DATA(bh), data + from, tmp);
 753                 if (buffer_new(bh)) {
 754                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 755                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 756                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 757                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 758                         AFFS_DATA_HEAD(bh)->next = 0;
 759                         bh->b_state &= ~(1UL << BH_New);
 760                         if (prev_bh) {
 761                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 762
 763                                 if (tmp_next)
 764                                         affs_warning(sb, "commit_write_ofs",
 765                                                      "next block already set for %d (%d)",
 766                                                      bidx, tmp_next);
 767                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 768                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 769                                 mark_buffer_dirty_inode(prev_bh, inode);
 770                         }
 771                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 772                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 773                 affs_brelse(prev_bh);
 774                 affs_fix_checksum(sb, bh);
 775                 mark_buffer_dirty_inode(bh, inode);
 776                 written += tmp;
 777                 from += tmp;
 778                 bidx++;
 779         }
 780         SetPageUptodate(page);
 781
 782 done:
 783         affs_brelse(bh);
 784         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 785         if (tmp > inode->i_size)
 786                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 787
 788         unlock_page(page);
 789         page_cache_release(page);
 790
 791         return written;
 792
 793 out:
 794         bh = prev_bh;
 795         if (!written)
 796                 written = PTR_ERR(bh);
 797         goto done;
 798 }
 799
 800 const struct address_space_operations affs_aops_ofs = {
 801         .readpage = affs_readpage_ofs,
 802         //.writepage = affs_writepage_ofs,
 803         .write_begin = affs_write_begin_ofs,
 804         .write_end = affs_write_end_ofs
 805 };
 806
 807 /* Free any preallocated blocks. */
 808
 809 void
 810 affs_free_prealloc(struct inode *inode)
 811 {
 812         struct super_block *sb = inode->i_sb;
 813
 814         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 815
 816         while (AFFS_I(inode)->i_pa_cnt) {
 817                 AFFS_I(inode)->i_pa_cnt--;
 818                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 819         }
 820 }
 821
 822 /* Truncate (or enlarge) a file to the requested size. */
 823
 824 void
 825 affs_truncate(struct inode *inode)
 826 {
 827         struct super_block *sb = inode->i_sb;
 828         u32 ext, ext_key;
 829         u32 last_blk, blkcnt, blk;
 830         u32 size;
 831         struct buffer_head *ext_bh;
 832         int i;
 833
 834         pr_debug("truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 835                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 836
 837         last_blk = 0;
 838         ext = 0;
 839         if (inode->i_size) {
 840                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 841                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 842         }
 843
 844         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 845                 struct address_space *mapping = inode->i_mapping;
 846                 struct page *page;
 847                 void *fsdata;
 848                 loff_t isize = inode->i_size;
 849                 int res;
 850
 851                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 852                 if (!res)
 853                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 854                 else
 855                         inode->i_size = AFFS_I(inode)->mmu_private;
 856                 mark_inode_dirty(inode);
 857                 return;
 858         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 859                 return;
 860
 861         // lock cache
 862         ext_bh = affs_get_extblock(inode, ext);
 863         if (IS_ERR(ext_bh)) {
 864                 affs_warning(sb, "truncate",
 865                              "unexpected read error for ext block %u (%ld)",
 866                              (unsigned int)ext, PTR_ERR(ext_bh));
 867                 return;
 868         }
 869         if (AFFS_I(inode)->i_lc) {
 870                 /* clear linear cache */
 871                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 872                 if (AFFS_I(inode)->i_lc_size > i) {
 873                         AFFS_I(inode)->i_lc_size = i;
 874                         for (; i < AFFS_LC_SIZE; i++)
 875                                 AFFS_I(inode)->i_lc[i] = 0;
 876                 }
 877                 /* clear associative cache */
 878                 for (i = 0; i < AFFS_AC_SIZE; i++)
 879                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 880                                 AFFS_I(inode)->i_ac[i].ext = 0;
 881         }
 882         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 883
 884         blkcnt = AFFS_I(inode)->i_blkcnt;
 885         i = 0;
 886         blk = last_blk;
 887         if (inode->i_size) {
 888                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 889                 blk++;
 890         } else
 891                 AFFS_HEAD(ext_bh)->first_data = 0;
 892         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 893         size = AFFS_SB(sb)->s_hashsize;
 894         if (size > blkcnt - blk + i)
 895                 size = blkcnt - blk + i;
 896         for (; i < size; i++, blk++) {
 897                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 898                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 899         }
 900         AFFS_TAIL(sb, ext_bh)->extension = 0;
 901         affs_fix_checksum(sb, ext_bh);
 902         mark_buffer_dirty_inode(ext_bh, inode);
 903         affs_brelse(ext_bh);
 904
 905         if (inode->i_size) {
 906                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 907                 AFFS_I(inode)->i_extcnt = ext + 1;
 908                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
 909                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 910                         u32 tmp;
 911                         if (IS_ERR(bh)) {
 912                                 affs_warning(sb, "truncate",
 913                                              "unexpected read error for last block %u (%ld)",
 914                                              (unsigned int)ext, PTR_ERR(bh));
 915                                 return;
 916                         }
 917                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 918                         AFFS_DATA_HEAD(bh)->next = 0;
 919                         affs_adjust_checksum(bh, -tmp);
 920                         affs_brelse(bh);
 921                 }
 922         } else {
 923                 AFFS_I(inode)->i_blkcnt = 0;
 924                 AFFS_I(inode)->i_extcnt = 1;
 925         }
 926         AFFS_I(inode)->mmu_private = inode->i_size;
 927         // unlock cache
 928
 929         while (ext_key) {
 930                 ext_bh = affs_bread(sb, ext_key);
 931                 size = AFFS_SB(sb)->s_hashsize;
 932                 if (size > blkcnt - blk)
 933                         size = blkcnt - blk;
 934                 for (i = 0; i < size; i++, blk++)
 935                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 936                 affs_free_block(sb, ext_key);
 937                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 938                 affs_brelse(ext_bh);
 939         }
 940         affs_free_prealloc(inode);
 941 }
 942
 943 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 944 {
 945         struct inode *inode = filp->f_mapping->host;
 946         int ret, err;
 947
 948         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 949         if (err)
 950                 return err;
 951
 952         mutex_lock(&inode->i_mutex);
 953         ret = write_inode_now(inode, 0);
 954         err = sync_blockdev(inode->i_sb->s_bdev);
 955         if (!ret)
 956                 ret = err;
 957         mutex_unlock(&inode->i_mutex);
 958         return ret;
 959 }
 960 const struct file_operations affs_file_operations = {
 961         .llseek         = generic_file_llseek,
 962         .read           = new_sync_read,
 963         .read_iter      = generic_file_read_iter,
 964         .write          = new_sync_write,
 965         .write_iter     = generic_file_write_iter,
 966         .mmap           = generic_file_mmap,
 967         .open           = affs_file_open,
 968         .release        = affs_file_release,
 969         .fsync          = affs_file_fsync,
 970         .splice_read    = generic_file_splice_read,
 971 };
 972
 973 const struct inode_operations affs_file_inode_operations = {
 974         .setattr        = affs_notify_change,
 975 };