linux/fs/affs/file.c
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   1/*
   2 *  linux/fs/affs/file.c
   3 *
   4 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   5 *
   6 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   7 *
   8 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   9 *
  10 *  (C) 1991  Linus Torvalds - minix filesystem
  11 *
  12 *  affs regular file handling primitives
  13 */
  14
  15#include <linux/uio.h>
  16#include "affs.h"
  17
  18static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  19
  20static int
  21affs_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
  29static int
  30affs_file_release(struct inode *inode, struct file *filp)
  31{
  32        pr_debug("release(%lu, %d)\n",
  33                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  34
  35        if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  36                inode_lock(inode);
  37                if (inode->i_size != AFFS_I(inode)->mmu_private)
  38                        affs_truncate(inode);
  39                affs_free_prealloc(inode);
  40                inode_unlock(inode);
  41        }
  42
  43        return 0;
  44}
  45
  46static int
  47affs_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
 111err:
 112        // lock cache
 113        return -EIO;
 114}
 115
 116static struct buffer_head *
 117affs_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
 154static inline struct buffer_head *
 155affs_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
 168static struct buffer_head *
 169affs_get_extblock_slow(struct inode *inode, u32 ext)
 170{
 171        struct super_block *sb = inode->i_sb;
 172        struct buffer_head *bh;
 173        u32 ext_key;
 174        u32 lc_idx, lc_off, ac_idx;
 175        u32 tmp, idx;
 176
 177        if (ext == AFFS_I(inode)->i_ext_last + 1) {
 178                /* read the next extended block from the current one */
 179                bh = AFFS_I(inode)->i_ext_bh;
 180                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 181                if (ext < AFFS_I(inode)->i_extcnt)
 182                        goto read_ext;
 183                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 184                bh = affs_alloc_extblock(inode, bh, ext);
 185                if (IS_ERR(bh))
 186                        return bh;
 187                goto store_ext;
 188        }
 189
 190        if (ext == 0) {
 191                /* we seek back to the file header block */
 192                ext_key = inode->i_ino;
 193                goto read_ext;
 194        }
 195
 196        if (ext >= AFFS_I(inode)->i_extcnt) {
 197                struct buffer_head *prev_bh;
 198
 199                /* allocate a new extended block */
 200                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 201
 202                /* get previous extended block */
 203                prev_bh = affs_get_extblock(inode, ext - 1);
 204                if (IS_ERR(prev_bh))
 205                        return prev_bh;
 206                bh = affs_alloc_extblock(inode, prev_bh, ext);
 207                affs_brelse(prev_bh);
 208                if (IS_ERR(bh))
 209                        return bh;
 210                goto store_ext;
 211        }
 212
 213again:
 214        /* check if there is an extended cache and whether it's large enough */
 215        lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 216        lc_off = ext & AFFS_I(inode)->i_lc_mask;
 217
 218        if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 219                int err;
 220
 221                err = affs_grow_extcache(inode, lc_idx);
 222                if (err)
 223                        return ERR_PTR(err);
 224                goto again;
 225        }
 226
 227        /* every n'th key we find in the linear cache */
 228        if (!lc_off) {
 229                ext_key = AFFS_I(inode)->i_lc[lc_idx];
 230                goto read_ext;
 231        }
 232
 233        /* maybe it's still in the associative cache */
 234        ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 235        if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 236                ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 237                goto read_ext;
 238        }
 239
 240        /* try to find one of the previous extended blocks */
 241        tmp = ext;
 242        idx = ac_idx;
 243        while (--tmp, --lc_off > 0) {
 244                idx = (idx - 1) & AFFS_AC_MASK;
 245                if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 246                        ext_key = AFFS_I(inode)->i_ac[idx].key;
 247                        goto find_ext;
 248                }
 249        }
 250
 251        /* fall back to the linear cache */
 252        ext_key = AFFS_I(inode)->i_lc[lc_idx];
 253find_ext:
 254        /* read all extended blocks until we find the one we need */
 255        //unlock cache
 256        do {
 257                bh = affs_bread(sb, ext_key);
 258                if (!bh)
 259                        goto err_bread;
 260                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 261                affs_brelse(bh);
 262                tmp++;
 263        } while (tmp < ext);
 264        //lock cache
 265
 266        /* store it in the associative cache */
 267        // recalculate ac_idx?
 268        AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 269        AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 270
 271read_ext:
 272        /* finally read the right extended block */
 273        //unlock cache
 274        bh = affs_bread(sb, ext_key);
 275        if (!bh)
 276                goto err_bread;
 277        //lock cache
 278
 279store_ext:
 280        /* release old cached extended block and store the new one */
 281        affs_brelse(AFFS_I(inode)->i_ext_bh);
 282        AFFS_I(inode)->i_ext_last = ext;
 283        AFFS_I(inode)->i_ext_bh = bh;
 284        get_bh(bh);
 285
 286        return bh;
 287
 288err_bread:
 289        affs_brelse(bh);
 290        return ERR_PTR(-EIO);
 291}
 292
 293static int
 294affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 295{
 296        struct super_block      *sb = inode->i_sb;
 297        struct buffer_head      *ext_bh;
 298        u32                      ext;
 299
 300        pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 301                 (unsigned long long)block);
 302
 303        BUG_ON(block > (sector_t)0x7fffffffUL);
 304
 305        if (block >= AFFS_I(inode)->i_blkcnt) {
 306                if (block > AFFS_I(inode)->i_blkcnt || !create)
 307                        goto err_big;
 308        } else
 309                create = 0;
 310
 311        //lock cache
 312        affs_lock_ext(inode);
 313
 314        ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 315        block -= ext * AFFS_SB(sb)->s_hashsize;
 316        ext_bh = affs_get_extblock(inode, ext);
 317        if (IS_ERR(ext_bh))
 318                goto err_ext;
 319        map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 320
 321        if (create) {
 322                u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 323                if (!blocknr)
 324                        goto err_alloc;
 325                set_buffer_new(bh_result);
 326                AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 327                AFFS_I(inode)->i_blkcnt++;
 328
 329                /* store new block */
 330                if (bh_result->b_blocknr)
 331                        affs_warning(sb, "get_block",
 332                                     "block already set (%llx)",
 333                                     (unsigned long long)bh_result->b_blocknr);
 334                AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 335                AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 336                affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 337                bh_result->b_blocknr = blocknr;
 338
 339                if (!block) {
 340                        /* insert first block into header block */
 341                        u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 342                        if (tmp)
 343                                affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 344                        AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 345                        affs_adjust_checksum(ext_bh, blocknr - tmp);
 346                }
 347        }
 348
 349        affs_brelse(ext_bh);
 350        //unlock cache
 351        affs_unlock_ext(inode);
 352        return 0;
 353
 354err_big:
 355        affs_error(inode->i_sb, "get_block", "strange block request %llu",
 356                   (unsigned long long)block);
 357        return -EIO;
 358err_ext:
 359        // unlock cache
 360        affs_unlock_ext(inode);
 361        return PTR_ERR(ext_bh);
 362err_alloc:
 363        brelse(ext_bh);
 364        clear_buffer_mapped(bh_result);
 365        bh_result->b_bdev = NULL;
 366        // unlock cache
 367        affs_unlock_ext(inode);
 368        return -ENOSPC;
 369}
 370
 371static int affs_writepage(struct page *page, struct writeback_control *wbc)
 372{
 373        return block_write_full_page(page, affs_get_block, wbc);
 374}
 375
 376static int affs_readpage(struct file *file, struct page *page)
 377{
 378        return block_read_full_page(page, affs_get_block);
 379}
 380
 381static void affs_write_failed(struct address_space *mapping, loff_t to)
 382{
 383        struct inode *inode = mapping->host;
 384
 385        if (to > inode->i_size) {
 386                truncate_pagecache(inode, inode->i_size);
 387                affs_truncate(inode);
 388        }
 389}
 390
 391static ssize_t
 392affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 393{
 394        struct file *file = iocb->ki_filp;
 395        struct address_space *mapping = file->f_mapping;
 396        struct inode *inode = mapping->host;
 397        size_t count = iov_iter_count(iter);
 398        loff_t offset = iocb->ki_pos;
 399        ssize_t ret;
 400
 401        if (iov_iter_rw(iter) == WRITE) {
 402                loff_t size = offset + count;
 403
 404                if (AFFS_I(inode)->mmu_private < size)
 405                        return 0;
 406        }
 407
 408        ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 409        if (ret < 0 && iov_iter_rw(iter) == WRITE)
 410                affs_write_failed(mapping, offset + count);
 411        return ret;
 412}
 413
 414static int affs_write_begin(struct file *file, struct address_space *mapping,
 415                        loff_t pos, unsigned len, unsigned flags,
 416                        struct page **pagep, void **fsdata)
 417{
 418        int ret;
 419
 420        *pagep = NULL;
 421        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 422                                affs_get_block,
 423                                &AFFS_I(mapping->host)->mmu_private);
 424        if (unlikely(ret))
 425                affs_write_failed(mapping, pos + len);
 426
 427        return ret;
 428}
 429
 430static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 431{
 432        return generic_block_bmap(mapping,block,affs_get_block);
 433}
 434
 435const struct address_space_operations affs_aops = {
 436        .readpage = affs_readpage,
 437        .writepage = affs_writepage,
 438        .write_begin = affs_write_begin,
 439        .write_end = generic_write_end,
 440        .direct_IO = affs_direct_IO,
 441        .bmap = _affs_bmap
 442};
 443
 444static inline struct buffer_head *
 445affs_bread_ino(struct inode *inode, int block, int create)
 446{
 447        struct buffer_head *bh, tmp_bh;
 448        int err;
 449
 450        tmp_bh.b_state = 0;
 451        err = affs_get_block(inode, block, &tmp_bh, create);
 452        if (!err) {
 453                bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 454                if (bh) {
 455                        bh->b_state |= tmp_bh.b_state;
 456                        return bh;
 457                }
 458                err = -EIO;
 459        }
 460        return ERR_PTR(err);
 461}
 462
 463static inline struct buffer_head *
 464affs_getzeroblk_ino(struct inode *inode, int block)
 465{
 466        struct buffer_head *bh, tmp_bh;
 467        int err;
 468
 469        tmp_bh.b_state = 0;
 470        err = affs_get_block(inode, block, &tmp_bh, 1);
 471        if (!err) {
 472                bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 473                if (bh) {
 474                        bh->b_state |= tmp_bh.b_state;
 475                        return bh;
 476                }
 477                err = -EIO;
 478        }
 479        return ERR_PTR(err);
 480}
 481
 482static inline struct buffer_head *
 483affs_getemptyblk_ino(struct inode *inode, int block)
 484{
 485        struct buffer_head *bh, tmp_bh;
 486        int err;
 487
 488        tmp_bh.b_state = 0;
 489        err = affs_get_block(inode, block, &tmp_bh, 1);
 490        if (!err) {
 491                bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 492                if (bh) {
 493                        bh->b_state |= tmp_bh.b_state;
 494                        return bh;
 495                }
 496                err = -EIO;
 497        }
 498        return ERR_PTR(err);
 499}
 500
 501static int
 502affs_do_readpage_ofs(struct page *page, unsigned to)
 503{
 504        struct inode *inode = page->mapping->host;
 505        struct super_block *sb = inode->i_sb;
 506        struct buffer_head *bh;
 507        char *data;
 508        unsigned pos = 0;
 509        u32 bidx, boff, bsize;
 510        u32 tmp;
 511
 512        pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 513                 page->index, to);
 514        BUG_ON(to > PAGE_SIZE);
 515        bsize = AFFS_SB(sb)->s_data_blksize;
 516        tmp = page->index << PAGE_SHIFT;
 517        bidx = tmp / bsize;
 518        boff = tmp % bsize;
 519
 520        while (pos < to) {
 521                bh = affs_bread_ino(inode, bidx, 0);
 522                if (IS_ERR(bh))
 523                        return PTR_ERR(bh);
 524                tmp = min(bsize - boff, to - pos);
 525                BUG_ON(pos + tmp > to || tmp > bsize);
 526                data = kmap_atomic(page);
 527                memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 528                kunmap_atomic(data);
 529                affs_brelse(bh);
 530                bidx++;
 531                pos += tmp;
 532                boff = 0;
 533        }
 534        flush_dcache_page(page);
 535        return 0;
 536}
 537
 538static int
 539affs_extent_file_ofs(struct inode *inode, u32 newsize)
 540{
 541        struct super_block *sb = inode->i_sb;
 542        struct buffer_head *bh, *prev_bh;
 543        u32 bidx, boff;
 544        u32 size, bsize;
 545        u32 tmp;
 546
 547        pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 548        bsize = AFFS_SB(sb)->s_data_blksize;
 549        bh = NULL;
 550        size = AFFS_I(inode)->mmu_private;
 551        bidx = size / bsize;
 552        boff = size % bsize;
 553        if (boff) {
 554                bh = affs_bread_ino(inode, bidx, 0);
 555                if (IS_ERR(bh))
 556                        return PTR_ERR(bh);
 557                tmp = min(bsize - boff, newsize - size);
 558                BUG_ON(boff + tmp > bsize || tmp > bsize);
 559                memset(AFFS_DATA(bh) + boff, 0, tmp);
 560                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 561                affs_fix_checksum(sb, bh);
 562                mark_buffer_dirty_inode(bh, inode);
 563                size += tmp;
 564                bidx++;
 565        } else if (bidx) {
 566                bh = affs_bread_ino(inode, bidx - 1, 0);
 567                if (IS_ERR(bh))
 568                        return PTR_ERR(bh);
 569        }
 570
 571        while (size < newsize) {
 572                prev_bh = bh;
 573                bh = affs_getzeroblk_ino(inode, bidx);
 574                if (IS_ERR(bh))
 575                        goto out;
 576                tmp = min(bsize, newsize - size);
 577                BUG_ON(tmp > bsize);
 578                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 579                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 580                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 581                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 582                affs_fix_checksum(sb, bh);
 583                bh->b_state &= ~(1UL << BH_New);
 584                mark_buffer_dirty_inode(bh, inode);
 585                if (prev_bh) {
 586                        u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 587
 588                        if (tmp_next)
 589                                affs_warning(sb, "extent_file_ofs",
 590                                             "next block already set for %d (%d)",
 591                                             bidx, tmp_next);
 592                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 593                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 594                        mark_buffer_dirty_inode(prev_bh, inode);
 595                        affs_brelse(prev_bh);
 596                }
 597                size += bsize;
 598                bidx++;
 599        }
 600        affs_brelse(bh);
 601        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 602        return 0;
 603
 604out:
 605        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 606        return PTR_ERR(bh);
 607}
 608
 609static int
 610affs_readpage_ofs(struct file *file, struct page *page)
 611{
 612        struct inode *inode = page->mapping->host;
 613        u32 to;
 614        int err;
 615
 616        pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 617        to = PAGE_SIZE;
 618        if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 619                to = inode->i_size & ~PAGE_MASK;
 620                memset(page_address(page) + to, 0, PAGE_SIZE - to);
 621        }
 622
 623        err = affs_do_readpage_ofs(page, to);
 624        if (!err)
 625                SetPageUptodate(page);
 626        unlock_page(page);
 627        return err;
 628}
 629
 630static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 631                                loff_t pos, unsigned len, unsigned flags,
 632                                struct page **pagep, void **fsdata)
 633{
 634        struct inode *inode = mapping->host;
 635        struct page *page;
 636        pgoff_t index;
 637        int err = 0;
 638
 639        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 640                 pos + len);
 641        if (pos > AFFS_I(inode)->mmu_private) {
 642                /* XXX: this probably leaves a too-big i_size in case of
 643                 * failure. Should really be updating i_size at write_end time
 644                 */
 645                err = affs_extent_file_ofs(inode, pos);
 646                if (err)
 647                        return err;
 648        }
 649
 650        index = pos >> PAGE_SHIFT;
 651        page = grab_cache_page_write_begin(mapping, index, flags);
 652        if (!page)
 653                return -ENOMEM;
 654        *pagep = page;
 655
 656        if (PageUptodate(page))
 657                return 0;
 658
 659        /* XXX: inefficient but safe in the face of short writes */
 660        err = affs_do_readpage_ofs(page, PAGE_SIZE);
 661        if (err) {
 662                unlock_page(page);
 663                put_page(page);
 664        }
 665        return err;
 666}
 667
 668static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 669                                loff_t pos, unsigned len, unsigned copied,
 670                                struct page *page, void *fsdata)
 671{
 672        struct inode *inode = mapping->host;
 673        struct super_block *sb = inode->i_sb;
 674        struct buffer_head *bh, *prev_bh;
 675        char *data;
 676        u32 bidx, boff, bsize;
 677        unsigned from, to;
 678        u32 tmp;
 679        int written;
 680
 681        from = pos & (PAGE_SIZE - 1);
 682        to = pos + len;
 683        /*
 684         * XXX: not sure if this can handle short copies (len < copied), but
 685         * we don't have to, because the page should always be uptodate here,
 686         * due to write_begin.
 687         */
 688
 689        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 690                 pos + len);
 691        bsize = AFFS_SB(sb)->s_data_blksize;
 692        data = page_address(page);
 693
 694        bh = NULL;
 695        written = 0;
 696        tmp = (page->index << PAGE_SHIFT) + from;
 697        bidx = tmp / bsize;
 698        boff = tmp % bsize;
 699        if (boff) {
 700                bh = affs_bread_ino(inode, bidx, 0);
 701                if (IS_ERR(bh)) {
 702                        written = PTR_ERR(bh);
 703                        goto err_first_bh;
 704                }
 705                tmp = min(bsize - boff, to - from);
 706                BUG_ON(boff + tmp > bsize || tmp > bsize);
 707                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 708                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 709                affs_fix_checksum(sb, bh);
 710                mark_buffer_dirty_inode(bh, inode);
 711                written += tmp;
 712                from += tmp;
 713                bidx++;
 714        } else if (bidx) {
 715                bh = affs_bread_ino(inode, bidx - 1, 0);
 716                if (IS_ERR(bh)) {
 717                        written = PTR_ERR(bh);
 718                        goto err_first_bh;
 719                }
 720        }
 721        while (from + bsize <= to) {
 722                prev_bh = bh;
 723                bh = affs_getemptyblk_ino(inode, bidx);
 724                if (IS_ERR(bh))
 725                        goto err_bh;
 726                memcpy(AFFS_DATA(bh), data + from, bsize);
 727                if (buffer_new(bh)) {
 728                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 729                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 730                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 731                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 732                        AFFS_DATA_HEAD(bh)->next = 0;
 733                        bh->b_state &= ~(1UL << BH_New);
 734                        if (prev_bh) {
 735                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 736
 737                                if (tmp_next)
 738                                        affs_warning(sb, "commit_write_ofs",
 739                                                     "next block already set for %d (%d)",
 740                                                     bidx, tmp_next);
 741                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 742                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 743                                mark_buffer_dirty_inode(prev_bh, inode);
 744                        }
 745                }
 746                affs_brelse(prev_bh);
 747                affs_fix_checksum(sb, bh);
 748                mark_buffer_dirty_inode(bh, inode);
 749                written += bsize;
 750                from += bsize;
 751                bidx++;
 752        }
 753        if (from < to) {
 754                prev_bh = bh;
 755                bh = affs_bread_ino(inode, bidx, 1);
 756                if (IS_ERR(bh))
 757                        goto err_bh;
 758                tmp = min(bsize, to - from);
 759                BUG_ON(tmp > bsize);
 760                memcpy(AFFS_DATA(bh), data + from, tmp);
 761                if (buffer_new(bh)) {
 762                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 763                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 764                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 765                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 766                        AFFS_DATA_HEAD(bh)->next = 0;
 767                        bh->b_state &= ~(1UL << BH_New);
 768                        if (prev_bh) {
 769                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 770
 771                                if (tmp_next)
 772                                        affs_warning(sb, "commit_write_ofs",
 773                                                     "next block already set for %d (%d)",
 774                                                     bidx, tmp_next);
 775                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 776                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 777                                mark_buffer_dirty_inode(prev_bh, inode);
 778                        }
 779                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 780                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 781                affs_brelse(prev_bh);
 782                affs_fix_checksum(sb, bh);
 783                mark_buffer_dirty_inode(bh, inode);
 784                written += tmp;
 785                from += tmp;
 786                bidx++;
 787        }
 788        SetPageUptodate(page);
 789
 790done:
 791        affs_brelse(bh);
 792        tmp = (page->index << PAGE_SHIFT) + from;
 793        if (tmp > inode->i_size)
 794                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 795
 796err_first_bh:
 797        unlock_page(page);
 798        put_page(page);
 799
 800        return written;
 801
 802err_bh:
 803        bh = prev_bh;
 804        if (!written)
 805                written = PTR_ERR(bh);
 806        goto done;
 807}
 808
 809const struct address_space_operations affs_aops_ofs = {
 810        .readpage = affs_readpage_ofs,
 811        //.writepage = affs_writepage_ofs,
 812        .write_begin = affs_write_begin_ofs,
 813        .write_end = affs_write_end_ofs
 814};
 815
 816/* Free any preallocated blocks. */
 817
 818void
 819affs_free_prealloc(struct inode *inode)
 820{
 821        struct super_block *sb = inode->i_sb;
 822
 823        pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 824
 825        while (AFFS_I(inode)->i_pa_cnt) {
 826                AFFS_I(inode)->i_pa_cnt--;
 827                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 828        }
 829}
 830
 831/* Truncate (or enlarge) a file to the requested size. */
 832
 833void
 834affs_truncate(struct inode *inode)
 835{
 836        struct super_block *sb = inode->i_sb;
 837        u32 ext, ext_key;
 838        u32 last_blk, blkcnt, blk;
 839        u32 size;
 840        struct buffer_head *ext_bh;
 841        int i;
 842
 843        pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 844                 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 845
 846        last_blk = 0;
 847        ext = 0;
 848        if (inode->i_size) {
 849                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 850                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 851        }
 852
 853        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 854                struct address_space *mapping = inode->i_mapping;
 855                struct page *page;
 856                void *fsdata;
 857                loff_t isize = inode->i_size;
 858                int res;
 859
 860                res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 861                if (!res)
 862                        res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 863                else
 864                        inode->i_size = AFFS_I(inode)->mmu_private;
 865                mark_inode_dirty(inode);
 866                return;
 867        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 868                return;
 869
 870        // lock cache
 871        ext_bh = affs_get_extblock(inode, ext);
 872        if (IS_ERR(ext_bh)) {
 873                affs_warning(sb, "truncate",
 874                             "unexpected read error for ext block %u (%ld)",
 875                             ext, PTR_ERR(ext_bh));
 876                return;
 877        }
 878        if (AFFS_I(inode)->i_lc) {
 879                /* clear linear cache */
 880                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 881                if (AFFS_I(inode)->i_lc_size > i) {
 882                        AFFS_I(inode)->i_lc_size = i;
 883                        for (; i < AFFS_LC_SIZE; i++)
 884                                AFFS_I(inode)->i_lc[i] = 0;
 885                }
 886                /* clear associative cache */
 887                for (i = 0; i < AFFS_AC_SIZE; i++)
 888                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 889                                AFFS_I(inode)->i_ac[i].ext = 0;
 890        }
 891        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 892
 893        blkcnt = AFFS_I(inode)->i_blkcnt;
 894        i = 0;
 895        blk = last_blk;
 896        if (inode->i_size) {
 897                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 898                blk++;
 899        } else
 900                AFFS_HEAD(ext_bh)->first_data = 0;
 901        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 902        size = AFFS_SB(sb)->s_hashsize;
 903        if (size > blkcnt - blk + i)
 904                size = blkcnt - blk + i;
 905        for (; i < size; i++, blk++) {
 906                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 907                AFFS_BLOCK(sb, ext_bh, i) = 0;
 908        }
 909        AFFS_TAIL(sb, ext_bh)->extension = 0;
 910        affs_fix_checksum(sb, ext_bh);
 911        mark_buffer_dirty_inode(ext_bh, inode);
 912        affs_brelse(ext_bh);
 913
 914        if (inode->i_size) {
 915                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 916                AFFS_I(inode)->i_extcnt = ext + 1;
 917                if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 918                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 919                        u32 tmp;
 920                        if (IS_ERR(bh)) {
 921                                affs_warning(sb, "truncate",
 922                                             "unexpected read error for last block %u (%ld)",
 923                                             ext, PTR_ERR(bh));
 924                                return;
 925                        }
 926                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 927                        AFFS_DATA_HEAD(bh)->next = 0;
 928                        affs_adjust_checksum(bh, -tmp);
 929                        affs_brelse(bh);
 930                }
 931        } else {
 932                AFFS_I(inode)->i_blkcnt = 0;
 933                AFFS_I(inode)->i_extcnt = 1;
 934        }
 935        AFFS_I(inode)->mmu_private = inode->i_size;
 936        // unlock cache
 937
 938        while (ext_key) {
 939                ext_bh = affs_bread(sb, ext_key);
 940                size = AFFS_SB(sb)->s_hashsize;
 941                if (size > blkcnt - blk)
 942                        size = blkcnt - blk;
 943                for (i = 0; i < size; i++, blk++)
 944                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 945                affs_free_block(sb, ext_key);
 946                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 947                affs_brelse(ext_bh);
 948        }
 949        affs_free_prealloc(inode);
 950}
 951
 952int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 953{
 954        struct inode *inode = filp->f_mapping->host;
 955        int ret, err;
 956
 957        err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 958        if (err)
 959                return err;
 960
 961        inode_lock(inode);
 962        ret = write_inode_now(inode, 0);
 963        err = sync_blockdev(inode->i_sb->s_bdev);
 964        if (!ret)
 965                ret = err;
 966        inode_unlock(inode);
 967        return ret;
 968}
 969const struct file_operations affs_file_operations = {
 970        .llseek         = generic_file_llseek,
 971        .read_iter      = generic_file_read_iter,
 972        .write_iter     = generic_file_write_iter,
 973        .mmap           = generic_file_mmap,
 974        .open           = affs_file_open,
 975        .release        = affs_file_release,
 976        .fsync          = affs_file_fsync,
 977        .splice_read    = generic_file_splice_read,
 978};
 979
 980const struct inode_operations affs_file_inode_operations = {
 981        .setattr        = affs_notify_change,
 982};
 983