fs/affs/file.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/affs/file.c
   4  *
   5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6  *
   7  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   8  *
   9  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
  10  *
  11  *  (C) 1991  Linus Torvalds - minix filesystem
  12  *
  13  *  affs regular file handling primitives
  14  */
  15
  16 #include <linux/uio.h>
  17 #include <linux/blkdev.h>
  18 #include "affs.h"
  19
  20 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  21
  22 static int
  23 affs_file_open(struct inode *inode, struct file *filp)
  24 {
  25         pr_debug("open(%lu,%d)\n",
  26                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  27         atomic_inc(&AFFS_I(inode)->i_opencnt);
  28         return 0;
  29 }
  30
  31 static int
  32 affs_file_release(struct inode *inode, struct file *filp)
  33 {
  34         pr_debug("release(%lu, %d)\n",
  35                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  36
  37         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  38                 inode_lock(inode);
  39                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  40                         affs_truncate(inode);
  41                 affs_free_prealloc(inode);
  42                 inode_unlock(inode);
  43         }
  44
  45         return 0;
  46 }
  47
  48 static int
  49 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  50 {
  51         struct super_block      *sb = inode->i_sb;
  52         struct buffer_head      *bh;
  53         u32 lc_max;
  54         int i, j, key;
  55
  56         if (!AFFS_I(inode)->i_lc) {
  57                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  58                 if (!ptr)
  59                         return -ENOMEM;
  60                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  61                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  62         }
  63
  64         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  65
  66         if (AFFS_I(inode)->i_extcnt > lc_max) {
  67                 u32 lc_shift, lc_mask, tmp, off;
  68
  69                 /* need to recalculate linear cache, start from old size */
  70                 lc_shift = AFFS_I(inode)->i_lc_shift;
  71                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  72                 for (; tmp; tmp >>= 1)
  73                         lc_shift++;
  74                 lc_mask = (1 << lc_shift) - 1;
  75
  76                 /* fix idx and old size to new shift */
  77                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  78                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79
  80                 /* first shrink old cache to make more space */
  81                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  82                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  83                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  84
  85                 AFFS_I(inode)->i_lc_shift = lc_shift;
  86                 AFFS_I(inode)->i_lc_mask = lc_mask;
  87         }
  88
  89         /* fill cache to the needed index */
  90         i = AFFS_I(inode)->i_lc_size;
  91         AFFS_I(inode)->i_lc_size = lc_idx + 1;
  92         for (; i <= lc_idx; i++) {
  93                 if (!i) {
  94                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
  95                         continue;
  96                 }
  97                 key = AFFS_I(inode)->i_lc[i - 1];
  98                 j = AFFS_I(inode)->i_lc_mask + 1;
  99                 // unlock cache
 100                 for (; j > 0; j--) {
 101                         bh = affs_bread(sb, key);
 102                         if (!bh)
 103                                 goto err;
 104                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 105                         affs_brelse(bh);
 106                 }
 107                 // lock cache
 108                 AFFS_I(inode)->i_lc[i] = key;
 109         }
 110
 111         return 0;
 112
 113 err:
 114         // lock cache
 115         return -EIO;
 116 }
 117
 118 static struct buffer_head *
 119 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 120 {
 121         struct super_block *sb = inode->i_sb;
 122         struct buffer_head *new_bh;
 123         u32 blocknr, tmp;
 124
 125         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 126         if (!blocknr)
 127                 return ERR_PTR(-ENOSPC);
 128
 129         new_bh = affs_getzeroblk(sb, blocknr);
 130         if (!new_bh) {
 131                 affs_free_block(sb, blocknr);
 132                 return ERR_PTR(-EIO);
 133         }
 134
 135         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 136         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 137         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 138         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 139         affs_fix_checksum(sb, new_bh);
 140
 141         mark_buffer_dirty_inode(new_bh, inode);
 142
 143         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 144         if (tmp)
 145                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 146         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 147         affs_adjust_checksum(bh, blocknr - tmp);
 148         mark_buffer_dirty_inode(bh, inode);
 149
 150         AFFS_I(inode)->i_extcnt++;
 151         mark_inode_dirty(inode);
 152
 153         return new_bh;
 154 }
 155
 156 static inline struct buffer_head *
 157 affs_get_extblock(struct inode *inode, u32 ext)
 158 {
 159         /* inline the simplest case: same extended block as last time */
 160         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 161         if (ext == AFFS_I(inode)->i_ext_last)
 162                 get_bh(bh);
 163         else
 164                 /* we have to do more (not inlined) */
 165                 bh = affs_get_extblock_slow(inode, ext);
 166
 167         return bh;
 168 }
 169
 170 static struct buffer_head *
 171 affs_get_extblock_slow(struct inode *inode, u32 ext)
 172 {
 173         struct super_block *sb = inode->i_sb;
 174         struct buffer_head *bh;
 175         u32 ext_key;
 176         u32 lc_idx, lc_off, ac_idx;
 177         u32 tmp, idx;
 178
 179         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 180                 /* read the next extended block from the current one */
 181                 bh = AFFS_I(inode)->i_ext_bh;
 182                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 183                 if (ext < AFFS_I(inode)->i_extcnt)
 184                         goto read_ext;
 185                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 186                 bh = affs_alloc_extblock(inode, bh, ext);
 187                 if (IS_ERR(bh))
 188                         return bh;
 189                 goto store_ext;
 190         }
 191
 192         if (ext == 0) {
 193                 /* we seek back to the file header block */
 194                 ext_key = inode->i_ino;
 195                 goto read_ext;
 196         }
 197
 198         if (ext >= AFFS_I(inode)->i_extcnt) {
 199                 struct buffer_head *prev_bh;
 200
 201                 /* allocate a new extended block */
 202                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 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(%lu, %llu)\n", __func__, inode->i_ino,
 303                  (unsigned long 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",
 334                                      "block already set (%llx)",
 335                                      (unsigned long long)bh_result->b_blocknr);
 336                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 337                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 338                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 339                 bh_result->b_blocknr = blocknr;
 340
 341                 if (!block) {
 342                         /* insert first block into header block */
 343                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 344                         if (tmp)
 345                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 346                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 347                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 348                 }
 349         }
 350
 351         affs_brelse(ext_bh);
 352         //unlock cache
 353         affs_unlock_ext(inode);
 354         return 0;
 355
 356 err_big:
 357         affs_error(inode->i_sb, "get_block", "strange block request %llu",
 358                    (unsigned long long)block);
 359         return -EIO;
 360 err_ext:
 361         // unlock cache
 362         affs_unlock_ext(inode);
 363         return PTR_ERR(ext_bh);
 364 err_alloc:
 365         brelse(ext_bh);
 366         clear_buffer_mapped(bh_result);
 367         bh_result->b_bdev = NULL;
 368         // unlock cache
 369         affs_unlock_ext(inode);
 370         return -ENOSPC;
 371 }
 372
 373 static int affs_writepage(struct page *page, struct writeback_control *wbc)
 374 {
 375         return block_write_full_page(page, affs_get_block, wbc);
 376 }
 377
 378 static int affs_readpage(struct file *file, struct page *page)
 379 {
 380         return block_read_full_page(page, affs_get_block);
 381 }
 382
 383 static void affs_write_failed(struct address_space *mapping, loff_t to)
 384 {
 385         struct inode *inode = mapping->host;
 386
 387         if (to > inode->i_size) {
 388                 truncate_pagecache(inode, inode->i_size);
 389                 affs_truncate(inode);
 390         }
 391 }
 392
 393 static ssize_t
 394 affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 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         loff_t offset = iocb->ki_pos;
 401         ssize_t ret;
 402
 403         if (iov_iter_rw(iter) == WRITE) {
 404                 loff_t size = offset + count;
 405
 406                 if (AFFS_I(inode)->mmu_private < size)
 407                         return 0;
 408         }
 409
 410         ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 411         if (ret < 0 && iov_iter_rw(iter) == WRITE)
 412                 affs_write_failed(mapping, offset + count);
 413         return ret;
 414 }
 415
 416 static int affs_write_begin(struct file *file, struct address_space *mapping,
 417                         loff_t pos, unsigned len, unsigned flags,
 418                         struct page **pagep, void **fsdata)
 419 {
 420         int ret;
 421
 422         *pagep = NULL;
 423         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 424                                 affs_get_block,
 425                                 &AFFS_I(mapping->host)->mmu_private);
 426         if (unlikely(ret))
 427                 affs_write_failed(mapping, pos + len);
 428
 429         return ret;
 430 }
 431
 432 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 433 {
 434         return generic_block_bmap(mapping,block,affs_get_block);
 435 }
 436
 437 const struct address_space_operations affs_aops = {
 438         .readpage = affs_readpage,
 439         .writepage = affs_writepage,
 440         .write_begin = affs_write_begin,
 441         .write_end = generic_write_end,
 442         .direct_IO = affs_direct_IO,
 443         .bmap = _affs_bmap
 444 };
 445
 446 static inline struct buffer_head *
 447 affs_bread_ino(struct inode *inode, int block, int create)
 448 {
 449         struct buffer_head *bh, tmp_bh;
 450         int err;
 451
 452         tmp_bh.b_state = 0;
 453         err = affs_get_block(inode, block, &tmp_bh, create);
 454         if (!err) {
 455                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 456                 if (bh) {
 457                         bh->b_state |= tmp_bh.b_state;
 458                         return bh;
 459                 }
 460                 err = -EIO;
 461         }
 462         return ERR_PTR(err);
 463 }
 464
 465 static inline struct buffer_head *
 466 affs_getzeroblk_ino(struct inode *inode, int block)
 467 {
 468         struct buffer_head *bh, tmp_bh;
 469         int err;
 470
 471         tmp_bh.b_state = 0;
 472         err = affs_get_block(inode, block, &tmp_bh, 1);
 473         if (!err) {
 474                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 475                 if (bh) {
 476                         bh->b_state |= tmp_bh.b_state;
 477                         return bh;
 478                 }
 479                 err = -EIO;
 480         }
 481         return ERR_PTR(err);
 482 }
 483
 484 static inline struct buffer_head *
 485 affs_getemptyblk_ino(struct inode *inode, int block)
 486 {
 487         struct buffer_head *bh, tmp_bh;
 488         int err;
 489
 490         tmp_bh.b_state = 0;
 491         err = affs_get_block(inode, block, &tmp_bh, 1);
 492         if (!err) {
 493                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 494                 if (bh) {
 495                         bh->b_state |= tmp_bh.b_state;
 496                         return bh;
 497                 }
 498                 err = -EIO;
 499         }
 500         return ERR_PTR(err);
 501 }
 502
 503 static int
 504 affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 505 {
 506         struct inode *inode = page->mapping->host;
 507         struct super_block *sb = inode->i_sb;
 508         struct buffer_head *bh;
 509         char *data;
 510         unsigned pos = 0;
 511         u32 bidx, boff, bsize;
 512         u32 tmp;
 513
 514         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 515                  page->index, to);
 516         BUG_ON(to > PAGE_SIZE);
 517         bsize = AFFS_SB(sb)->s_data_blksize;
 518         tmp = page->index << PAGE_SHIFT;
 519         bidx = tmp / bsize;
 520         boff = tmp % bsize;
 521
 522         while (pos < to) {
 523                 bh = affs_bread_ino(inode, bidx, create);
 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                 data = kmap_atomic(page);
 529                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 530                 kunmap_atomic(data);
 531                 affs_brelse(bh);
 532                 bidx++;
 533                 pos += tmp;
 534                 boff = 0;
 535         }
 536         flush_dcache_page(page);
 537         return 0;
 538 }
 539
 540 static int
 541 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 542 {
 543         struct super_block *sb = inode->i_sb;
 544         struct buffer_head *bh, *prev_bh;
 545         u32 bidx, boff;
 546         u32 size, bsize;
 547         u32 tmp;
 548
 549         pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 550         bsize = AFFS_SB(sb)->s_data_blksize;
 551         bh = NULL;
 552         size = AFFS_I(inode)->mmu_private;
 553         bidx = size / bsize;
 554         boff = size % bsize;
 555         if (boff) {
 556                 bh = affs_bread_ino(inode, bidx, 0);
 557                 if (IS_ERR(bh))
 558                         return PTR_ERR(bh);
 559                 tmp = min(bsize - boff, newsize - size);
 560                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 561                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 562                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 563                 affs_fix_checksum(sb, bh);
 564                 mark_buffer_dirty_inode(bh, inode);
 565                 size += tmp;
 566                 bidx++;
 567         } else if (bidx) {
 568                 bh = affs_bread_ino(inode, bidx - 1, 0);
 569                 if (IS_ERR(bh))
 570                         return PTR_ERR(bh);
 571         }
 572
 573         while (size < newsize) {
 574                 prev_bh = bh;
 575                 bh = affs_getzeroblk_ino(inode, bidx);
 576                 if (IS_ERR(bh))
 577                         goto out;
 578                 tmp = min(bsize, newsize - size);
 579                 BUG_ON(tmp > bsize);
 580                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 581                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 582                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 583                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 584                 affs_fix_checksum(sb, bh);
 585                 bh->b_state &= ~(1UL << BH_New);
 586                 mark_buffer_dirty_inode(bh, inode);
 587                 if (prev_bh) {
 588                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 589
 590                         if (tmp_next)
 591                                 affs_warning(sb, "extent_file_ofs",
 592                                              "next block already set for %d (%d)",
 593                                              bidx, tmp_next);
 594                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 595                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 596                         mark_buffer_dirty_inode(prev_bh, inode);
 597                         affs_brelse(prev_bh);
 598                 }
 599                 size += bsize;
 600                 bidx++;
 601         }
 602         affs_brelse(bh);
 603         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 604         return 0;
 605
 606 out:
 607         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 608         return PTR_ERR(bh);
 609 }
 610
 611 static int
 612 affs_readpage_ofs(struct file *file, struct page *page)
 613 {
 614         struct inode *inode = page->mapping->host;
 615         u32 to;
 616         int err;
 617
 618         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 619         to = PAGE_SIZE;
 620         if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 621                 to = inode->i_size & ~PAGE_MASK;
 622                 memset(page_address(page) + to, 0, PAGE_SIZE - to);
 623         }
 624
 625         err = affs_do_readpage_ofs(page, to, 0);
 626         if (!err)
 627                 SetPageUptodate(page);
 628         unlock_page(page);
 629         return err;
 630 }
 631
 632 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 633                                 loff_t pos, unsigned len, unsigned flags,
 634                                 struct page **pagep, void **fsdata)
 635 {
 636         struct inode *inode = mapping->host;
 637         struct page *page;
 638         pgoff_t index;
 639         int err = 0;
 640
 641         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 642                  pos + len);
 643         if (pos > AFFS_I(inode)->mmu_private) {
 644                 /* XXX: this probably leaves a too-big i_size in case of
 645                  * failure. Should really be updating i_size at write_end time
 646                  */
 647                 err = affs_extent_file_ofs(inode, pos);
 648                 if (err)
 649                         return err;
 650         }
 651
 652         index = pos >> PAGE_SHIFT;
 653         page = grab_cache_page_write_begin(mapping, index, flags);
 654         if (!page)
 655                 return -ENOMEM;
 656         *pagep = page;
 657
 658         if (PageUptodate(page))
 659                 return 0;
 660
 661         /* XXX: inefficient but safe in the face of short writes */
 662         err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 663         if (err) {
 664                 unlock_page(page);
 665                 put_page(page);
 666         }
 667         return err;
 668 }
 669
 670 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 671                                 loff_t pos, unsigned len, unsigned copied,
 672                                 struct page *page, void *fsdata)
 673 {
 674         struct inode *inode = mapping->host;
 675         struct super_block *sb = inode->i_sb;
 676         struct buffer_head *bh, *prev_bh;
 677         char *data;
 678         u32 bidx, boff, bsize;
 679         unsigned from, to;
 680         u32 tmp;
 681         int written;
 682
 683         from = pos & (PAGE_SIZE - 1);
 684         to = from + len;
 685         /*
 686          * XXX: not sure if this can handle short copies (len < copied), but
 687          * we don't have to, because the page should always be uptodate here,
 688          * due to write_begin.
 689          */
 690
 691         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 692                  pos + len);
 693         bsize = AFFS_SB(sb)->s_data_blksize;
 694         data = page_address(page);
 695
 696         bh = NULL;
 697         written = 0;
 698         tmp = (page->index << PAGE_SHIFT) + from;
 699         bidx = tmp / bsize;
 700         boff = tmp % bsize;
 701         if (boff) {
 702                 bh = affs_bread_ino(inode, bidx, 0);
 703                 if (IS_ERR(bh)) {
 704                         written = PTR_ERR(bh);
 705                         goto err_first_bh;
 706                 }
 707                 tmp = min(bsize - boff, to - from);
 708                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 709                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 710                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 711                 affs_fix_checksum(sb, bh);
 712                 mark_buffer_dirty_inode(bh, inode);
 713                 written += tmp;
 714                 from += tmp;
 715                 bidx++;
 716         } else if (bidx) {
 717                 bh = affs_bread_ino(inode, bidx - 1, 0);
 718                 if (IS_ERR(bh)) {
 719                         written = PTR_ERR(bh);
 720                         goto err_first_bh;
 721                 }
 722         }
 723         while (from + bsize <= to) {
 724                 prev_bh = bh;
 725                 bh = affs_getemptyblk_ino(inode, bidx);
 726                 if (IS_ERR(bh))
 727                         goto err_bh;
 728                 memcpy(AFFS_DATA(bh), data + from, bsize);
 729                 if (buffer_new(bh)) {
 730                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 731                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 732                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 733                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 734                         AFFS_DATA_HEAD(bh)->next = 0;
 735                         bh->b_state &= ~(1UL << BH_New);
 736                         if (prev_bh) {
 737                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 738
 739                                 if (tmp_next)
 740                                         affs_warning(sb, "commit_write_ofs",
 741                                                      "next block already set for %d (%d)",
 742                                                      bidx, tmp_next);
 743                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 744                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 745                                 mark_buffer_dirty_inode(prev_bh, inode);
 746                         }
 747                 }
 748                 affs_brelse(prev_bh);
 749                 affs_fix_checksum(sb, bh);
 750                 mark_buffer_dirty_inode(bh, inode);
 751                 written += bsize;
 752                 from += bsize;
 753                 bidx++;
 754         }
 755         if (from < to) {
 756                 prev_bh = bh;
 757                 bh = affs_bread_ino(inode, bidx, 1);
 758                 if (IS_ERR(bh))
 759                         goto err_bh;
 760                 tmp = min(bsize, to - from);
 761                 BUG_ON(tmp > bsize);
 762                 memcpy(AFFS_DATA(bh), data + from, tmp);
 763                 if (buffer_new(bh)) {
 764                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 765                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 766                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 767                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 768                         AFFS_DATA_HEAD(bh)->next = 0;
 769                         bh->b_state &= ~(1UL << BH_New);
 770                         if (prev_bh) {
 771                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 772
 773                                 if (tmp_next)
 774                                         affs_warning(sb, "commit_write_ofs",
 775                                                      "next block already set for %d (%d)",
 776                                                      bidx, tmp_next);
 777                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 778                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 779                                 mark_buffer_dirty_inode(prev_bh, inode);
 780                         }
 781                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 782                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 783                 affs_brelse(prev_bh);
 784                 affs_fix_checksum(sb, bh);
 785                 mark_buffer_dirty_inode(bh, inode);
 786                 written += tmp;
 787                 from += tmp;
 788                 bidx++;
 789         }
 790         SetPageUptodate(page);
 791
 792 done:
 793         affs_brelse(bh);
 794         tmp = (page->index << PAGE_SHIFT) + from;
 795         if (tmp > inode->i_size)
 796                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 797
 798 err_first_bh:
 799         unlock_page(page);
 800         put_page(page);
 801
 802         return written;
 803
 804 err_bh:
 805         bh = prev_bh;
 806         if (!written)
 807                 written = PTR_ERR(bh);
 808         goto done;
 809 }
 810
 811 const struct address_space_operations affs_aops_ofs = {
 812         .readpage = affs_readpage_ofs,
 813         //.writepage = affs_writepage_ofs,
 814         .write_begin = affs_write_begin_ofs,
 815         .write_end = affs_write_end_ofs
 816 };
 817
 818 /* Free any preallocated blocks. */
 819
 820 void
 821 affs_free_prealloc(struct inode *inode)
 822 {
 823         struct super_block *sb = inode->i_sb;
 824
 825         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 826
 827         while (AFFS_I(inode)->i_pa_cnt) {
 828                 AFFS_I(inode)->i_pa_cnt--;
 829                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 830         }
 831 }
 832
 833 /* Truncate (or enlarge) a file to the requested size. */
 834
 835 void
 836 affs_truncate(struct inode *inode)
 837 {
 838         struct super_block *sb = inode->i_sb;
 839         u32 ext, ext_key;
 840         u32 last_blk, blkcnt, blk;
 841         u32 size;
 842         struct buffer_head *ext_bh;
 843         int i;
 844
 845         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 846                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 847
 848         last_blk = 0;
 849         ext = 0;
 850         if (inode->i_size) {
 851                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 852                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 853         }
 854
 855         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 856                 struct address_space *mapping = inode->i_mapping;
 857                 struct page *page;
 858                 void *fsdata;
 859                 loff_t isize = inode->i_size;
 860                 int res;
 861
 862                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 863                 if (!res)
 864                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 865                 else
 866                         inode->i_size = AFFS_I(inode)->mmu_private;
 867                 mark_inode_dirty(inode);
 868                 return;
 869         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 870                 return;
 871
 872         // lock cache
 873         ext_bh = affs_get_extblock(inode, ext);
 874         if (IS_ERR(ext_bh)) {
 875                 affs_warning(sb, "truncate",
 876                              "unexpected read error for ext block %u (%ld)",
 877                              ext, PTR_ERR(ext_bh));
 878                 return;
 879         }
 880         if (AFFS_I(inode)->i_lc) {
 881                 /* clear linear cache */
 882                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 883                 if (AFFS_I(inode)->i_lc_size > i) {
 884                         AFFS_I(inode)->i_lc_size = i;
 885                         for (; i < AFFS_LC_SIZE; i++)
 886                                 AFFS_I(inode)->i_lc[i] = 0;
 887                 }
 888                 /* clear associative cache */
 889                 for (i = 0; i < AFFS_AC_SIZE; i++)
 890                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 891                                 AFFS_I(inode)->i_ac[i].ext = 0;
 892         }
 893         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 894
 895         blkcnt = AFFS_I(inode)->i_blkcnt;
 896         i = 0;
 897         blk = last_blk;
 898         if (inode->i_size) {
 899                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 900                 blk++;
 901         } else
 902                 AFFS_HEAD(ext_bh)->first_data = 0;
 903         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 904         size = AFFS_SB(sb)->s_hashsize;
 905         if (size > blkcnt - blk + i)
 906                 size = blkcnt - blk + i;
 907         for (; i < size; i++, blk++) {
 908                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 909                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 910         }
 911         AFFS_TAIL(sb, ext_bh)->extension = 0;
 912         affs_fix_checksum(sb, ext_bh);
 913         mark_buffer_dirty_inode(ext_bh, inode);
 914         affs_brelse(ext_bh);
 915
 916         if (inode->i_size) {
 917                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 918                 AFFS_I(inode)->i_extcnt = ext + 1;
 919                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 920                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 921                         u32 tmp;
 922                         if (IS_ERR(bh)) {
 923                                 affs_warning(sb, "truncate",
 924                                              "unexpected read error for last block %u (%ld)",
 925                                              ext, PTR_ERR(bh));
 926                                 return;
 927                         }
 928                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 929                         AFFS_DATA_HEAD(bh)->next = 0;
 930                         affs_adjust_checksum(bh, -tmp);
 931                         affs_brelse(bh);
 932                 }
 933         } else {
 934                 AFFS_I(inode)->i_blkcnt = 0;
 935                 AFFS_I(inode)->i_extcnt = 1;
 936         }
 937         AFFS_I(inode)->mmu_private = inode->i_size;
 938         // unlock cache
 939
 940         while (ext_key) {
 941                 ext_bh = affs_bread(sb, ext_key);
 942                 size = AFFS_SB(sb)->s_hashsize;
 943                 if (size > blkcnt - blk)
 944                         size = blkcnt - blk;
 945                 for (i = 0; i < size; i++, blk++)
 946                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 947                 affs_free_block(sb, ext_key);
 948                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 949                 affs_brelse(ext_bh);
 950         }
 951         affs_free_prealloc(inode);
 952 }
 953
 954 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 955 {
 956         struct inode *inode = filp->f_mapping->host;
 957         int ret, err;
 958
 959         err = file_write_and_wait_range(filp, start, end);
 960         if (err)
 961                 return err;
 962
 963         inode_lock(inode);
 964         ret = write_inode_now(inode, 0);
 965         err = sync_blockdev(inode->i_sb->s_bdev);
 966         if (!ret)
 967                 ret = err;
 968         inode_unlock(inode);
 969         return ret;
 970 }
 971 const struct file_operations affs_file_operations = {
 972         .llseek         = generic_file_llseek,
 973         .read_iter      = generic_file_read_iter,
 974         .write_iter     = generic_file_write_iter,
 975         .mmap           = generic_file_mmap,
 976         .open           = affs_file_open,
 977         .release        = affs_file_release,
 978         .fsync          = affs_file_fsync,
 979         .splice_read    = generic_file_splice_read,
 980 };
 981
 982 const struct inode_operations affs_file_inode_operations = {
 983         .setattr        = affs_notify_change,
 984 };