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 "affs.h"
  18
  19 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  20
  21 static int
  22 affs_file_open(struct inode *inode, struct file *filp)
  23 {
  24         pr_debug("open(%lu,%d)\n",
  25                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  26         atomic_inc(&AFFS_I(inode)->i_opencnt);
  27         return 0;
  28 }
  29
  30 static int
  31 affs_file_release(struct inode *inode, struct file *filp)
  32 {
  33         pr_debug("release(%lu, %d)\n",
  34                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  35
  36         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  37                 inode_lock(inode);
  38                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  39                         affs_truncate(inode);
  40                 affs_free_prealloc(inode);
  41                 inode_unlock(inode);
  42         }
  43
  44         return 0;
  45 }
  46
  47 static int
  48 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  49 {
  50         struct super_block      *sb = inode->i_sb;
  51         struct buffer_head      *bh;
  52         u32 lc_max;
  53         int i, j, key;
  54
  55         if (!AFFS_I(inode)->i_lc) {
  56                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  57                 if (!ptr)
  58                         return -ENOMEM;
  59                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  60                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  61         }
  62
  63         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  64
  65         if (AFFS_I(inode)->i_extcnt > lc_max) {
  66                 u32 lc_shift, lc_mask, tmp, off;
  67
  68                 /* need to recalculate linear cache, start from old size */
  69                 lc_shift = AFFS_I(inode)->i_lc_shift;
  70                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  71                 for (; tmp; tmp >>= 1)
  72                         lc_shift++;
  73                 lc_mask = (1 << lc_shift) - 1;
  74
  75                 /* fix idx and old size to new shift */
  76                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  77                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  78
  79                 /* first shrink old cache to make more space */
  80                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  81                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  82                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  83
  84                 AFFS_I(inode)->i_lc_shift = lc_shift;
  85                 AFFS_I(inode)->i_lc_mask = lc_mask;
  86         }
  87
  88         /* fill cache to the needed index */
  89         i = AFFS_I(inode)->i_lc_size;
  90         AFFS_I(inode)->i_lc_size = lc_idx + 1;
  91         for (; i <= lc_idx; i++) {
  92                 if (!i) {
  93                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
  94                         continue;
  95                 }
  96                 key = AFFS_I(inode)->i_lc[i - 1];
  97                 j = AFFS_I(inode)->i_lc_mask + 1;
  98                 // unlock cache
  99                 for (; j > 0; j--) {
 100                         bh = affs_bread(sb, key);
 101                         if (!bh)
 102                                 goto err;
 103                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 104                         affs_brelse(bh);
 105                 }
 106                 // lock cache
 107                 AFFS_I(inode)->i_lc[i] = key;
 108         }
 109
 110         return 0;
 111
 112 err:
 113         // lock cache
 114         return -EIO;
 115 }
 116
 117 static struct buffer_head *
 118 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 119 {
 120         struct super_block *sb = inode->i_sb;
 121         struct buffer_head *new_bh;
 122         u32 blocknr, tmp;
 123
 124         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 125         if (!blocknr)
 126                 return ERR_PTR(-ENOSPC);
 127
 128         new_bh = affs_getzeroblk(sb, blocknr);
 129         if (!new_bh) {
 130                 affs_free_block(sb, blocknr);
 131                 return ERR_PTR(-EIO);
 132         }
 133
 134         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 135         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 136         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 137         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 138         affs_fix_checksum(sb, new_bh);
 139
 140         mark_buffer_dirty_inode(new_bh, inode);
 141
 142         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 143         if (tmp)
 144                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 145         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 146         affs_adjust_checksum(bh, blocknr - tmp);
 147         mark_buffer_dirty_inode(bh, inode);
 148
 149         AFFS_I(inode)->i_extcnt++;
 150         mark_inode_dirty(inode);
 151
 152         return new_bh;
 153 }
 154
 155 static inline struct buffer_head *
 156 affs_get_extblock(struct inode *inode, u32 ext)
 157 {
 158         /* inline the simplest case: same extended block as last time */
 159         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 160         if (ext == AFFS_I(inode)->i_ext_last)
 161                 get_bh(bh);
 162         else
 163                 /* we have to do more (not inlined) */
 164                 bh = affs_get_extblock_slow(inode, ext);
 165
 166         return bh;
 167 }
 168
 169 static struct buffer_head *
 170 affs_get_extblock_slow(struct inode *inode, u32 ext)
 171 {
 172         struct super_block *sb = inode->i_sb;
 173         struct buffer_head *bh;
 174         u32 ext_key;
 175         u32 lc_idx, lc_off, ac_idx;
 176         u32 tmp, idx;
 177
 178         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 179                 /* read the next extended block from the current one */
 180                 bh = AFFS_I(inode)->i_ext_bh;
 181                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 182                 if (ext < AFFS_I(inode)->i_extcnt)
 183                         goto read_ext;
 184                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 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                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 202
 203                 /* get previous extended block */
 204                 prev_bh = affs_get_extblock(inode, ext - 1);
 205                 if (IS_ERR(prev_bh))
 206                         return prev_bh;
 207                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 208                 affs_brelse(prev_bh);
 209                 if (IS_ERR(bh))
 210                         return bh;
 211                 goto store_ext;
 212         }
 213
 214 again:
 215         /* check if there is an extended cache and whether it's large enough */
 216         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 217         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 218
 219         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 220                 int err;
 221
 222                 err = affs_grow_extcache(inode, lc_idx);
 223                 if (err)
 224                         return ERR_PTR(err);
 225                 goto again;
 226         }
 227
 228         /* every n'th key we find in the linear cache */
 229         if (!lc_off) {
 230                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 231                 goto read_ext;
 232         }
 233
 234         /* maybe it's still in the associative cache */
 235         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 236         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 237                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 238                 goto read_ext;
 239         }
 240
 241         /* try to find one of the previous extended blocks */
 242         tmp = ext;
 243         idx = ac_idx;
 244         while (--tmp, --lc_off > 0) {
 245                 idx = (idx - 1) & AFFS_AC_MASK;
 246                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 247                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 248                         goto find_ext;
 249                 }
 250         }
 251
 252         /* fall back to the linear cache */
 253         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 254 find_ext:
 255         /* read all extended blocks until we find the one we need */
 256         //unlock cache
 257         do {
 258                 bh = affs_bread(sb, ext_key);
 259                 if (!bh)
 260                         goto err_bread;
 261                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 262                 affs_brelse(bh);
 263                 tmp++;
 264         } while (tmp < ext);
 265         //lock cache
 266
 267         /* store it in the associative cache */
 268         // recalculate ac_idx?
 269         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 270         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 271
 272 read_ext:
 273         /* finally read the right extended block */
 274         //unlock cache
 275         bh = affs_bread(sb, ext_key);
 276         if (!bh)
 277                 goto err_bread;
 278         //lock cache
 279
 280 store_ext:
 281         /* release old cached extended block and store the new one */
 282         affs_brelse(AFFS_I(inode)->i_ext_bh);
 283         AFFS_I(inode)->i_ext_last = ext;
 284         AFFS_I(inode)->i_ext_bh = bh;
 285         get_bh(bh);
 286
 287         return bh;
 288
 289 err_bread:
 290         affs_brelse(bh);
 291         return ERR_PTR(-EIO);
 292 }
 293
 294 static int
 295 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 296 {
 297         struct super_block      *sb = inode->i_sb;
 298         struct buffer_head      *ext_bh;
 299         u32                      ext;
 300
 301         pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 302                  (unsigned long long)block);
 303
 304         BUG_ON(block > (sector_t)0x7fffffffUL);
 305
 306         if (block >= AFFS_I(inode)->i_blkcnt) {
 307                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 308                         goto err_big;
 309         } else
 310                 create = 0;
 311
 312         //lock cache
 313         affs_lock_ext(inode);
 314
 315         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 316         block -= ext * AFFS_SB(sb)->s_hashsize;
 317         ext_bh = affs_get_extblock(inode, ext);
 318         if (IS_ERR(ext_bh))
 319                 goto err_ext;
 320         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 321
 322         if (create) {
 323                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 324                 if (!blocknr)
 325                         goto err_alloc;
 326                 set_buffer_new(bh_result);
 327                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 328                 AFFS_I(inode)->i_blkcnt++;
 329
 330                 /* store new block */
 331                 if (bh_result->b_blocknr)
 332                         affs_warning(sb, "get_block",
 333                                      "block already set (%llx)",
 334                                      (unsigned long 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 %llu",
 357                    (unsigned long long)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(struct kiocb *iocb, struct iov_iter *iter)
 394 {
 395         struct file *file = iocb->ki_filp;
 396         struct address_space *mapping = file->f_mapping;
 397         struct inode *inode = mapping->host;
 398         size_t count = iov_iter_count(iter);
 399         loff_t offset = iocb->ki_pos;
 400         ssize_t ret;
 401
 402         if (iov_iter_rw(iter) == WRITE) {
 403                 loff_t size = offset + count;
 404
 405                 if (AFFS_I(inode)->mmu_private < size)
 406                         return 0;
 407         }
 408
 409         ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 410         if (ret < 0 && iov_iter_rw(iter) == WRITE)
 411                 affs_write_failed(mapping, offset + count);
 412         return ret;
 413 }
 414
 415 static int affs_write_begin(struct file *file, struct address_space *mapping,
 416                         loff_t pos, unsigned len, unsigned flags,
 417                         struct page **pagep, void **fsdata)
 418 {
 419         int ret;
 420
 421         *pagep = NULL;
 422         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 423                                 affs_get_block,
 424                                 &AFFS_I(mapping->host)->mmu_private);
 425         if (unlikely(ret))
 426                 affs_write_failed(mapping, pos + len);
 427
 428         return ret;
 429 }
 430
 431 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 432 {
 433         return generic_block_bmap(mapping,block,affs_get_block);
 434 }
 435
 436 const struct address_space_operations affs_aops = {
 437         .readpage = affs_readpage,
 438         .writepage = affs_writepage,
 439         .write_begin = affs_write_begin,
 440         .write_end = generic_write_end,
 441         .direct_IO = affs_direct_IO,
 442         .bmap = _affs_bmap
 443 };
 444
 445 static inline struct buffer_head *
 446 affs_bread_ino(struct inode *inode, int block, int create)
 447 {
 448         struct buffer_head *bh, tmp_bh;
 449         int err;
 450
 451         tmp_bh.b_state = 0;
 452         err = affs_get_block(inode, block, &tmp_bh, create);
 453         if (!err) {
 454                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 455                 if (bh) {
 456                         bh->b_state |= tmp_bh.b_state;
 457                         return bh;
 458                 }
 459                 err = -EIO;
 460         }
 461         return ERR_PTR(err);
 462 }
 463
 464 static inline struct buffer_head *
 465 affs_getzeroblk_ino(struct inode *inode, int block)
 466 {
 467         struct buffer_head *bh, tmp_bh;
 468         int err;
 469
 470         tmp_bh.b_state = 0;
 471         err = affs_get_block(inode, block, &tmp_bh, 1);
 472         if (!err) {
 473                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 474                 if (bh) {
 475                         bh->b_state |= tmp_bh.b_state;
 476                         return bh;
 477                 }
 478                 err = -EIO;
 479         }
 480         return ERR_PTR(err);
 481 }
 482
 483 static inline struct buffer_head *
 484 affs_getemptyblk_ino(struct inode *inode, int block)
 485 {
 486         struct buffer_head *bh, tmp_bh;
 487         int err;
 488
 489         tmp_bh.b_state = 0;
 490         err = affs_get_block(inode, block, &tmp_bh, 1);
 491         if (!err) {
 492                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 493                 if (bh) {
 494                         bh->b_state |= tmp_bh.b_state;
 495                         return bh;
 496                 }
 497                 err = -EIO;
 498         }
 499         return ERR_PTR(err);
 500 }
 501
 502 static int
 503 affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 504 {
 505         struct inode *inode = page->mapping->host;
 506         struct super_block *sb = inode->i_sb;
 507         struct buffer_head *bh;
 508         char *data;
 509         unsigned pos = 0;
 510         u32 bidx, boff, bsize;
 511         u32 tmp;
 512
 513         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 514                  page->index, to);
 515         BUG_ON(to > PAGE_SIZE);
 516         bsize = AFFS_SB(sb)->s_data_blksize;
 517         tmp = page->index << PAGE_SHIFT;
 518         bidx = tmp / bsize;
 519         boff = tmp % bsize;
 520
 521         while (pos < to) {
 522                 bh = affs_bread_ino(inode, bidx, create);
 523                 if (IS_ERR(bh))
 524                         return PTR_ERR(bh);
 525                 tmp = min(bsize - boff, to - pos);
 526                 BUG_ON(pos + tmp > to || tmp > bsize);
 527                 data = kmap_atomic(page);
 528                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 529                 kunmap_atomic(data);
 530                 affs_brelse(bh);
 531                 bidx++;
 532                 pos += tmp;
 533                 boff = 0;
 534         }
 535         flush_dcache_page(page);
 536         return 0;
 537 }
 538
 539 static int
 540 affs_extent_file_ofs(struct inode *inode, u32 newsize)
 541 {
 542         struct super_block *sb = inode->i_sb;
 543         struct buffer_head *bh, *prev_bh;
 544         u32 bidx, boff;
 545         u32 size, bsize;
 546         u32 tmp;
 547
 548         pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 549         bsize = AFFS_SB(sb)->s_data_blksize;
 550         bh = NULL;
 551         size = AFFS_I(inode)->mmu_private;
 552         bidx = size / bsize;
 553         boff = size % bsize;
 554         if (boff) {
 555                 bh = affs_bread_ino(inode, bidx, 0);
 556                 if (IS_ERR(bh))
 557                         return PTR_ERR(bh);
 558                 tmp = min(bsize - boff, newsize - size);
 559                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 560                 memset(AFFS_DATA(bh) + boff, 0, tmp);
 561                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 562                 affs_fix_checksum(sb, bh);
 563                 mark_buffer_dirty_inode(bh, inode);
 564                 size += tmp;
 565                 bidx++;
 566         } else if (bidx) {
 567                 bh = affs_bread_ino(inode, bidx - 1, 0);
 568                 if (IS_ERR(bh))
 569                         return PTR_ERR(bh);
 570         }
 571
 572         while (size < newsize) {
 573                 prev_bh = bh;
 574                 bh = affs_getzeroblk_ino(inode, bidx);
 575                 if (IS_ERR(bh))
 576                         goto out;
 577                 tmp = min(bsize, newsize - size);
 578                 BUG_ON(tmp > bsize);
 579                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 580                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 581                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 582                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 583                 affs_fix_checksum(sb, bh);
 584                 bh->b_state &= ~(1UL << BH_New);
 585                 mark_buffer_dirty_inode(bh, inode);
 586                 if (prev_bh) {
 587                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 588
 589                         if (tmp_next)
 590                                 affs_warning(sb, "extent_file_ofs",
 591                                              "next block already set for %d (%d)",
 592                                              bidx, tmp_next);
 593                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 594                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 595                         mark_buffer_dirty_inode(prev_bh, inode);
 596                         affs_brelse(prev_bh);
 597                 }
 598                 size += bsize;
 599                 bidx++;
 600         }
 601         affs_brelse(bh);
 602         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 603         return 0;
 604
 605 out:
 606         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 607         return PTR_ERR(bh);
 608 }
 609
 610 static int
 611 affs_readpage_ofs(struct file *file, struct page *page)
 612 {
 613         struct inode *inode = page->mapping->host;
 614         u32 to;
 615         int err;
 616
 617         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 618         to = PAGE_SIZE;
 619         if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 620                 to = inode->i_size & ~PAGE_MASK;
 621                 memset(page_address(page) + to, 0, PAGE_SIZE - to);
 622         }
 623
 624         err = affs_do_readpage_ofs(page, to, 0);
 625         if (!err)
 626                 SetPageUptodate(page);
 627         unlock_page(page);
 628         return err;
 629 }
 630
 631 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 632                                 loff_t pos, unsigned len, unsigned flags,
 633                                 struct page **pagep, void **fsdata)
 634 {
 635         struct inode *inode = mapping->host;
 636         struct page *page;
 637         pgoff_t index;
 638         int err = 0;
 639
 640         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 641                  pos + len);
 642         if (pos > AFFS_I(inode)->mmu_private) {
 643                 /* XXX: this probably leaves a too-big i_size in case of
 644                  * failure. Should really be updating i_size at write_end time
 645                  */
 646                 err = affs_extent_file_ofs(inode, pos);
 647                 if (err)
 648                         return err;
 649         }
 650
 651         index = pos >> PAGE_SHIFT;
 652         page = grab_cache_page_write_begin(mapping, index, flags);
 653         if (!page)
 654                 return -ENOMEM;
 655         *pagep = page;
 656
 657         if (PageUptodate(page))
 658                 return 0;
 659
 660         /* XXX: inefficient but safe in the face of short writes */
 661         err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 662         if (err) {
 663                 unlock_page(page);
 664                 put_page(page);
 665         }
 666         return err;
 667 }
 668
 669 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 670                                 loff_t pos, unsigned len, unsigned copied,
 671                                 struct page *page, void *fsdata)
 672 {
 673         struct inode *inode = mapping->host;
 674         struct super_block *sb = inode->i_sb;
 675         struct buffer_head *bh, *prev_bh;
 676         char *data;
 677         u32 bidx, boff, bsize;
 678         unsigned from, to;
 679         u32 tmp;
 680         int written;
 681
 682         from = pos & (PAGE_SIZE - 1);
 683         to = from + len;
 684         /*
 685          * XXX: not sure if this can handle short copies (len < copied), but
 686          * we don't have to, because the page should always be uptodate here,
 687          * due to write_begin.
 688          */
 689
 690         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 691                  pos + len);
 692         bsize = AFFS_SB(sb)->s_data_blksize;
 693         data = page_address(page);
 694
 695         bh = NULL;
 696         written = 0;
 697         tmp = (page->index << PAGE_SHIFT) + from;
 698         bidx = tmp / bsize;
 699         boff = tmp % bsize;
 700         if (boff) {
 701                 bh = affs_bread_ino(inode, bidx, 0);
 702                 if (IS_ERR(bh)) {
 703                         written = PTR_ERR(bh);
 704                         goto err_first_bh;
 705                 }
 706                 tmp = min(bsize - boff, to - from);
 707                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 708                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 709                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 710                 affs_fix_checksum(sb, bh);
 711                 mark_buffer_dirty_inode(bh, inode);
 712                 written += tmp;
 713                 from += tmp;
 714                 bidx++;
 715         } else if (bidx) {
 716                 bh = affs_bread_ino(inode, bidx - 1, 0);
 717                 if (IS_ERR(bh)) {
 718                         written = PTR_ERR(bh);
 719                         goto err_first_bh;
 720                 }
 721         }
 722         while (from + bsize <= to) {
 723                 prev_bh = bh;
 724                 bh = affs_getemptyblk_ino(inode, bidx);
 725                 if (IS_ERR(bh))
 726                         goto err_bh;
 727                 memcpy(AFFS_DATA(bh), data + from, bsize);
 728                 if (buffer_new(bh)) {
 729                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 730                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 731                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 732                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 733                         AFFS_DATA_HEAD(bh)->next = 0;
 734                         bh->b_state &= ~(1UL << BH_New);
 735                         if (prev_bh) {
 736                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 737
 738                                 if (tmp_next)
 739                                         affs_warning(sb, "commit_write_ofs",
 740                                                      "next block already set for %d (%d)",
 741                                                      bidx, tmp_next);
 742                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 743                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 744                                 mark_buffer_dirty_inode(prev_bh, inode);
 745                         }
 746                 }
 747                 affs_brelse(prev_bh);
 748                 affs_fix_checksum(sb, bh);
 749                 mark_buffer_dirty_inode(bh, inode);
 750                 written += bsize;
 751                 from += bsize;
 752                 bidx++;
 753         }
 754         if (from < to) {
 755                 prev_bh = bh;
 756                 bh = affs_bread_ino(inode, bidx, 1);
 757                 if (IS_ERR(bh))
 758                         goto err_bh;
 759                 tmp = min(bsize, to - from);
 760                 BUG_ON(tmp > bsize);
 761                 memcpy(AFFS_DATA(bh), data + from, tmp);
 762                 if (buffer_new(bh)) {
 763                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 764                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 765                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 766                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 767                         AFFS_DATA_HEAD(bh)->next = 0;
 768                         bh->b_state &= ~(1UL << BH_New);
 769                         if (prev_bh) {
 770                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 771
 772                                 if (tmp_next)
 773                                         affs_warning(sb, "commit_write_ofs",
 774                                                      "next block already set for %d (%d)",
 775                                                      bidx, tmp_next);
 776                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 777                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 778                                 mark_buffer_dirty_inode(prev_bh, inode);
 779                         }
 780                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 781                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 782                 affs_brelse(prev_bh);
 783                 affs_fix_checksum(sb, bh);
 784                 mark_buffer_dirty_inode(bh, inode);
 785                 written += tmp;
 786                 from += tmp;
 787                 bidx++;
 788         }
 789         SetPageUptodate(page);
 790
 791 done:
 792         affs_brelse(bh);
 793         tmp = (page->index << PAGE_SHIFT) + from;
 794         if (tmp > inode->i_size)
 795                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 796
 797 err_first_bh:
 798         unlock_page(page);
 799         put_page(page);
 800
 801         return written;
 802
 803 err_bh:
 804         bh = prev_bh;
 805         if (!written)
 806                 written = PTR_ERR(bh);
 807         goto done;
 808 }
 809
 810 const struct address_space_operations affs_aops_ofs = {
 811         .readpage = affs_readpage_ofs,
 812         //.writepage = affs_writepage_ofs,
 813         .write_begin = affs_write_begin_ofs,
 814         .write_end = affs_write_end_ofs
 815 };
 816
 817 /* Free any preallocated blocks. */
 818
 819 void
 820 affs_free_prealloc(struct inode *inode)
 821 {
 822         struct super_block *sb = inode->i_sb;
 823
 824         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 825
 826         while (AFFS_I(inode)->i_pa_cnt) {
 827                 AFFS_I(inode)->i_pa_cnt--;
 828                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 829         }
 830 }
 831
 832 /* Truncate (or enlarge) a file to the requested size. */
 833
 834 void
 835 affs_truncate(struct inode *inode)
 836 {
 837         struct super_block *sb = inode->i_sb;
 838         u32 ext, ext_key;
 839         u32 last_blk, blkcnt, blk;
 840         u32 size;
 841         struct buffer_head *ext_bh;
 842         int i;
 843
 844         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 845                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 846
 847         last_blk = 0;
 848         ext = 0;
 849         if (inode->i_size) {
 850                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 851                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 852         }
 853
 854         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 855                 struct address_space *mapping = inode->i_mapping;
 856                 struct page *page;
 857                 void *fsdata;
 858                 loff_t isize = inode->i_size;
 859                 int res;
 860
 861                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 862                 if (!res)
 863                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 864                 else
 865                         inode->i_size = AFFS_I(inode)->mmu_private;
 866                 mark_inode_dirty(inode);
 867                 return;
 868         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 869                 return;
 870
 871         // lock cache
 872         ext_bh = affs_get_extblock(inode, ext);
 873         if (IS_ERR(ext_bh)) {
 874                 affs_warning(sb, "truncate",
 875                              "unexpected read error for ext block %u (%ld)",
 876                              ext, PTR_ERR(ext_bh));
 877                 return;
 878         }
 879         if (AFFS_I(inode)->i_lc) {
 880                 /* clear linear cache */
 881                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 882                 if (AFFS_I(inode)->i_lc_size > i) {
 883                         AFFS_I(inode)->i_lc_size = i;
 884                         for (; i < AFFS_LC_SIZE; i++)
 885                                 AFFS_I(inode)->i_lc[i] = 0;
 886                 }
 887                 /* clear associative cache */
 888                 for (i = 0; i < AFFS_AC_SIZE; i++)
 889                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 890                                 AFFS_I(inode)->i_ac[i].ext = 0;
 891         }
 892         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 893
 894         blkcnt = AFFS_I(inode)->i_blkcnt;
 895         i = 0;
 896         blk = last_blk;
 897         if (inode->i_size) {
 898                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 899                 blk++;
 900         } else
 901                 AFFS_HEAD(ext_bh)->first_data = 0;
 902         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 903         size = AFFS_SB(sb)->s_hashsize;
 904         if (size > blkcnt - blk + i)
 905                 size = blkcnt - blk + i;
 906         for (; i < size; i++, blk++) {
 907                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 908                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 909         }
 910         AFFS_TAIL(sb, ext_bh)->extension = 0;
 911         affs_fix_checksum(sb, ext_bh);
 912         mark_buffer_dirty_inode(ext_bh, inode);
 913         affs_brelse(ext_bh);
 914
 915         if (inode->i_size) {
 916                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 917                 AFFS_I(inode)->i_extcnt = ext + 1;
 918                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 919                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 920                         u32 tmp;
 921                         if (IS_ERR(bh)) {
 922                                 affs_warning(sb, "truncate",
 923                                              "unexpected read error for last block %u (%ld)",
 924                                              ext, PTR_ERR(bh));
 925                                 return;
 926                         }
 927                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 928                         AFFS_DATA_HEAD(bh)->next = 0;
 929                         affs_adjust_checksum(bh, -tmp);
 930                         affs_brelse(bh);
 931                 }
 932         } else {
 933                 AFFS_I(inode)->i_blkcnt = 0;
 934                 AFFS_I(inode)->i_extcnt = 1;
 935         }
 936         AFFS_I(inode)->mmu_private = inode->i_size;
 937         // unlock cache
 938
 939         while (ext_key) {
 940                 ext_bh = affs_bread(sb, ext_key);
 941                 size = AFFS_SB(sb)->s_hashsize;
 942                 if (size > blkcnt - blk)
 943                         size = blkcnt - blk;
 944                 for (i = 0; i < size; i++, blk++)
 945                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 946                 affs_free_block(sb, ext_key);
 947                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 948                 affs_brelse(ext_bh);
 949         }
 950         affs_free_prealloc(inode);
 951 }
 952
 953 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 954 {
 955         struct inode *inode = filp->f_mapping->host;
 956         int ret, err;
 957
 958         err = file_write_and_wait_range(filp, start, end);
 959         if (err)
 960                 return err;
 961
 962         inode_lock(inode);
 963         ret = write_inode_now(inode, 0);
 964         err = sync_blockdev(inode->i_sb->s_bdev);
 965         if (!ret)
 966                 ret = err;
 967         inode_unlock(inode);
 968         return ret;
 969 }
 970 const struct file_operations affs_file_operations = {
 971         .llseek         = generic_file_llseek,
 972         .read_iter      = generic_file_read_iter,
 973         .write_iter     = generic_file_write_iter,
 974         .mmap           = generic_file_mmap,
 975         .open           = affs_file_open,
 976         .release        = affs_file_release,
 977         .fsync          = affs_file_fsync,
 978         .splice_read    = generic_file_splice_read,
 979 };
 980
 981 const struct inode_operations affs_file_inode_operations = {
 982         .setattr        = affs_notify_change,
 983 };