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 "affs.h"
  16
  17#if PAGE_SIZE < 4096
  18#error PAGE_SIZE must be at least 4096
  19#endif
  20
  21static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
  22static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
  23static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
  24static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  25static int affs_file_open(struct inode *inode, struct file *filp);
  26static int affs_file_release(struct inode *inode, struct file *filp);
  27
  28const struct file_operations affs_file_operations = {
  29        .llseek         = generic_file_llseek,
  30        .read           = do_sync_read,
  31        .aio_read       = generic_file_aio_read,
  32        .write          = do_sync_write,
  33        .aio_write      = generic_file_aio_write,
  34        .mmap           = generic_file_mmap,
  35        .open           = affs_file_open,
  36        .release        = affs_file_release,
  37        .fsync          = affs_file_fsync,
  38        .splice_read    = generic_file_splice_read,
  39};
  40
  41const struct inode_operations affs_file_inode_operations = {
  42        .setattr        = affs_notify_change,
  43};
  44
  45static int
  46affs_file_open(struct inode *inode, struct file *filp)
  47{
  48        pr_debug("AFFS: open(%lu,%d)\n",
  49                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  50        atomic_inc(&AFFS_I(inode)->i_opencnt);
  51        return 0;
  52}
  53
  54static int
  55affs_file_release(struct inode *inode, struct file *filp)
  56{
  57        pr_debug("AFFS: release(%lu, %d)\n",
  58                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  59
  60        if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  61                mutex_lock(&inode->i_mutex);
  62                if (inode->i_size != AFFS_I(inode)->mmu_private)
  63                        affs_truncate(inode);
  64                affs_free_prealloc(inode);
  65                mutex_unlock(&inode->i_mutex);
  66        }
  67
  68        return 0;
  69}
  70
  71static int
  72affs_grow_extcache(struct inode *inode, u32 lc_idx)
  73{
  74        struct super_block      *sb = inode->i_sb;
  75        struct buffer_head      *bh;
  76        u32 lc_max;
  77        int i, j, key;
  78
  79        if (!AFFS_I(inode)->i_lc) {
  80                char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  81                if (!ptr)
  82                        return -ENOMEM;
  83                AFFS_I(inode)->i_lc = (u32 *)ptr;
  84                AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  85        }
  86
  87        lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  88
  89        if (AFFS_I(inode)->i_extcnt > lc_max) {
  90                u32 lc_shift, lc_mask, tmp, off;
  91
  92                /* need to recalculate linear cache, start from old size */
  93                lc_shift = AFFS_I(inode)->i_lc_shift;
  94                tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  95                for (; tmp; tmp >>= 1)
  96                        lc_shift++;
  97                lc_mask = (1 << lc_shift) - 1;
  98
  99                /* fix idx and old size to new shift */
 100                lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 101                AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
 102
 103                /* first shrink old cache to make more space */
 104                off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
 105                for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
 106                        AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
 107
 108                AFFS_I(inode)->i_lc_shift = lc_shift;
 109                AFFS_I(inode)->i_lc_mask = lc_mask;
 110        }
 111
 112        /* fill cache to the needed index */
 113        i = AFFS_I(inode)->i_lc_size;
 114        AFFS_I(inode)->i_lc_size = lc_idx + 1;
 115        for (; i <= lc_idx; i++) {
 116                if (!i) {
 117                        AFFS_I(inode)->i_lc[0] = inode->i_ino;
 118                        continue;
 119                }
 120                key = AFFS_I(inode)->i_lc[i - 1];
 121                j = AFFS_I(inode)->i_lc_mask + 1;
 122                // unlock cache
 123                for (; j > 0; j--) {
 124                        bh = affs_bread(sb, key);
 125                        if (!bh)
 126                                goto err;
 127                        key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 128                        affs_brelse(bh);
 129                }
 130                // lock cache
 131                AFFS_I(inode)->i_lc[i] = key;
 132        }
 133
 134        return 0;
 135
 136err:
 137        // lock cache
 138        return -EIO;
 139}
 140
 141static struct buffer_head *
 142affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 143{
 144        struct super_block *sb = inode->i_sb;
 145        struct buffer_head *new_bh;
 146        u32 blocknr, tmp;
 147
 148        blocknr = affs_alloc_block(inode, bh->b_blocknr);
 149        if (!blocknr)
 150                return ERR_PTR(-ENOSPC);
 151
 152        new_bh = affs_getzeroblk(sb, blocknr);
 153        if (!new_bh) {
 154                affs_free_block(sb, blocknr);
 155                return ERR_PTR(-EIO);
 156        }
 157
 158        AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 159        AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 160        AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 161        AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 162        affs_fix_checksum(sb, new_bh);
 163
 164        mark_buffer_dirty_inode(new_bh, inode);
 165
 166        tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 167        if (tmp)
 168                affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 169        AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 170        affs_adjust_checksum(bh, blocknr - tmp);
 171        mark_buffer_dirty_inode(bh, inode);
 172
 173        AFFS_I(inode)->i_extcnt++;
 174        mark_inode_dirty(inode);
 175
 176        return new_bh;
 177}
 178
 179static inline struct buffer_head *
 180affs_get_extblock(struct inode *inode, u32 ext)
 181{
 182        /* inline the simplest case: same extended block as last time */
 183        struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 184        if (ext == AFFS_I(inode)->i_ext_last)
 185                get_bh(bh);
 186        else
 187                /* we have to do more (not inlined) */
 188                bh = affs_get_extblock_slow(inode, ext);
 189
 190        return bh;
 191}
 192
 193static struct buffer_head *
 194affs_get_extblock_slow(struct inode *inode, u32 ext)
 195{
 196        struct super_block *sb = inode->i_sb;
 197        struct buffer_head *bh;
 198        u32 ext_key;
 199        u32 lc_idx, lc_off, ac_idx;
 200        u32 tmp, idx;
 201
 202        if (ext == AFFS_I(inode)->i_ext_last + 1) {
 203                /* read the next extended block from the current one */
 204                bh = AFFS_I(inode)->i_ext_bh;
 205                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 206                if (ext < AFFS_I(inode)->i_extcnt)
 207                        goto read_ext;
 208                if (ext > AFFS_I(inode)->i_extcnt)
 209                        BUG();
 210                bh = affs_alloc_extblock(inode, bh, ext);
 211                if (IS_ERR(bh))
 212                        return bh;
 213                goto store_ext;
 214        }
 215
 216        if (ext == 0) {
 217                /* we seek back to the file header block */
 218                ext_key = inode->i_ino;
 219                goto read_ext;
 220        }
 221
 222        if (ext >= AFFS_I(inode)->i_extcnt) {
 223                struct buffer_head *prev_bh;
 224
 225                /* allocate a new extended block */
 226                if (ext > AFFS_I(inode)->i_extcnt)
 227                        BUG();
 228
 229                /* get previous extended block */
 230                prev_bh = affs_get_extblock(inode, ext - 1);
 231                if (IS_ERR(prev_bh))
 232                        return prev_bh;
 233                bh = affs_alloc_extblock(inode, prev_bh, ext);
 234                affs_brelse(prev_bh);
 235                if (IS_ERR(bh))
 236                        return bh;
 237                goto store_ext;
 238        }
 239
 240again:
 241        /* check if there is an extended cache and whether it's large enough */
 242        lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 243        lc_off = ext & AFFS_I(inode)->i_lc_mask;
 244
 245        if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 246                int err;
 247
 248                err = affs_grow_extcache(inode, lc_idx);
 249                if (err)
 250                        return ERR_PTR(err);
 251                goto again;
 252        }
 253
 254        /* every n'th key we find in the linear cache */
 255        if (!lc_off) {
 256                ext_key = AFFS_I(inode)->i_lc[lc_idx];
 257                goto read_ext;
 258        }
 259
 260        /* maybe it's still in the associative cache */
 261        ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 262        if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 263                ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 264                goto read_ext;
 265        }
 266
 267        /* try to find one of the previous extended blocks */
 268        tmp = ext;
 269        idx = ac_idx;
 270        while (--tmp, --lc_off > 0) {
 271                idx = (idx - 1) & AFFS_AC_MASK;
 272                if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 273                        ext_key = AFFS_I(inode)->i_ac[idx].key;
 274                        goto find_ext;
 275                }
 276        }
 277
 278        /* fall back to the linear cache */
 279        ext_key = AFFS_I(inode)->i_lc[lc_idx];
 280find_ext:
 281        /* read all extended blocks until we find the one we need */
 282        //unlock cache
 283        do {
 284                bh = affs_bread(sb, ext_key);
 285                if (!bh)
 286                        goto err_bread;
 287                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 288                affs_brelse(bh);
 289                tmp++;
 290        } while (tmp < ext);
 291        //lock cache
 292
 293        /* store it in the associative cache */
 294        // recalculate ac_idx?
 295        AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 296        AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 297
 298read_ext:
 299        /* finally read the right extended block */
 300        //unlock cache
 301        bh = affs_bread(sb, ext_key);
 302        if (!bh)
 303                goto err_bread;
 304        //lock cache
 305
 306store_ext:
 307        /* release old cached extended block and store the new one */
 308        affs_brelse(AFFS_I(inode)->i_ext_bh);
 309        AFFS_I(inode)->i_ext_last = ext;
 310        AFFS_I(inode)->i_ext_bh = bh;
 311        get_bh(bh);
 312
 313        return bh;
 314
 315err_bread:
 316        affs_brelse(bh);
 317        return ERR_PTR(-EIO);
 318}
 319
 320static int
 321affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 322{
 323        struct super_block      *sb = inode->i_sb;
 324        struct buffer_head      *ext_bh;
 325        u32                      ext;
 326
 327        pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
 328
 329        BUG_ON(block > (sector_t)0x7fffffffUL);
 330
 331        if (block >= AFFS_I(inode)->i_blkcnt) {
 332                if (block > AFFS_I(inode)->i_blkcnt || !create)
 333                        goto err_big;
 334        } else
 335                create = 0;
 336
 337        //lock cache
 338        affs_lock_ext(inode);
 339
 340        ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 341        block -= ext * AFFS_SB(sb)->s_hashsize;
 342        ext_bh = affs_get_extblock(inode, ext);
 343        if (IS_ERR(ext_bh))
 344                goto err_ext;
 345        map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 346
 347        if (create) {
 348                u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 349                if (!blocknr)
 350                        goto err_alloc;
 351                set_buffer_new(bh_result);
 352                AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 353                AFFS_I(inode)->i_blkcnt++;
 354
 355                /* store new block */
 356                if (bh_result->b_blocknr)
 357                        affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
 358                AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 359                AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 360                affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 361                bh_result->b_blocknr = blocknr;
 362
 363                if (!block) {
 364                        /* insert first block into header block */
 365                        u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 366                        if (tmp)
 367                                affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 368                        AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 369                        affs_adjust_checksum(ext_bh, blocknr - tmp);
 370                }
 371        }
 372
 373        affs_brelse(ext_bh);
 374        //unlock cache
 375        affs_unlock_ext(inode);
 376        return 0;
 377
 378err_big:
 379        affs_error(inode->i_sb,"get_block","strange block request %d", block);
 380        return -EIO;
 381err_ext:
 382        // unlock cache
 383        affs_unlock_ext(inode);
 384        return PTR_ERR(ext_bh);
 385err_alloc:
 386        brelse(ext_bh);
 387        clear_buffer_mapped(bh_result);
 388        bh_result->b_bdev = NULL;
 389        // unlock cache
 390        affs_unlock_ext(inode);
 391        return -ENOSPC;
 392}
 393
 394static int affs_writepage(struct page *page, struct writeback_control *wbc)
 395{
 396        return block_write_full_page(page, affs_get_block, wbc);
 397}
 398
 399static int affs_readpage(struct file *file, struct page *page)
 400{
 401        return block_read_full_page(page, affs_get_block);
 402}
 403
 404static void affs_write_failed(struct address_space *mapping, loff_t to)
 405{
 406        struct inode *inode = mapping->host;
 407
 408        if (to > inode->i_size) {
 409                truncate_pagecache(inode, to, inode->i_size);
 410                affs_truncate(inode);
 411        }
 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        .bmap = _affs_bmap
 441};
 442
 443static inline struct buffer_head *
 444affs_bread_ino(struct inode *inode, int block, int create)
 445{
 446        struct buffer_head *bh, tmp_bh;
 447        int err;
 448
 449        tmp_bh.b_state = 0;
 450        err = affs_get_block(inode, block, &tmp_bh, create);
 451        if (!err) {
 452                bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 453                if (bh) {
 454                        bh->b_state |= tmp_bh.b_state;
 455                        return bh;
 456                }
 457                err = -EIO;
 458        }
 459        return ERR_PTR(err);
 460}
 461
 462static inline struct buffer_head *
 463affs_getzeroblk_ino(struct inode *inode, int block)
 464{
 465        struct buffer_head *bh, tmp_bh;
 466        int err;
 467
 468        tmp_bh.b_state = 0;
 469        err = affs_get_block(inode, block, &tmp_bh, 1);
 470        if (!err) {
 471                bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 472                if (bh) {
 473                        bh->b_state |= tmp_bh.b_state;
 474                        return bh;
 475                }
 476                err = -EIO;
 477        }
 478        return ERR_PTR(err);
 479}
 480
 481static inline struct buffer_head *
 482affs_getemptyblk_ino(struct inode *inode, int block)
 483{
 484        struct buffer_head *bh, tmp_bh;
 485        int err;
 486
 487        tmp_bh.b_state = 0;
 488        err = affs_get_block(inode, block, &tmp_bh, 1);
 489        if (!err) {
 490                bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 491                if (bh) {
 492                        bh->b_state |= tmp_bh.b_state;
 493                        return bh;
 494                }
 495                err = -EIO;
 496        }
 497        return ERR_PTR(err);
 498}
 499
 500static int
 501affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
 502{
 503        struct inode *inode = page->mapping->host;
 504        struct super_block *sb = inode->i_sb;
 505        struct buffer_head *bh;
 506        char *data;
 507        u32 bidx, boff, bsize;
 508        u32 tmp;
 509
 510        pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
 511        BUG_ON(from > to || to > PAGE_CACHE_SIZE);
 512        kmap(page);
 513        data = page_address(page);
 514        bsize = AFFS_SB(sb)->s_data_blksize;
 515        tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 516        bidx = tmp / bsize;
 517        boff = tmp % bsize;
 518
 519        while (from < to) {
 520                bh = affs_bread_ino(inode, bidx, 0);
 521                if (IS_ERR(bh))
 522                        return PTR_ERR(bh);
 523                tmp = min(bsize - boff, to - from);
 524                BUG_ON(from + tmp > to || tmp > bsize);
 525                memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
 526                affs_brelse(bh);
 527                bidx++;
 528                from += tmp;
 529                boff = 0;
 530        }
 531        flush_dcache_page(page);
 532        kunmap(page);
 533        return 0;
 534}
 535
 536static int
 537affs_extent_file_ofs(struct inode *inode, u32 newsize)
 538{
 539        struct super_block *sb = inode->i_sb;
 540        struct buffer_head *bh, *prev_bh;
 541        u32 bidx, boff;
 542        u32 size, bsize;
 543        u32 tmp;
 544
 545        pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
 546        bsize = AFFS_SB(sb)->s_data_blksize;
 547        bh = NULL;
 548        size = AFFS_I(inode)->mmu_private;
 549        bidx = size / bsize;
 550        boff = size % bsize;
 551        if (boff) {
 552                bh = affs_bread_ino(inode, bidx, 0);
 553                if (IS_ERR(bh))
 554                        return PTR_ERR(bh);
 555                tmp = min(bsize - boff, newsize - size);
 556                BUG_ON(boff + tmp > bsize || tmp > bsize);
 557                memset(AFFS_DATA(bh) + boff, 0, tmp);
 558                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 559                affs_fix_checksum(sb, bh);
 560                mark_buffer_dirty_inode(bh, inode);
 561                size += tmp;
 562                bidx++;
 563        } else if (bidx) {
 564                bh = affs_bread_ino(inode, bidx - 1, 0);
 565                if (IS_ERR(bh))
 566                        return PTR_ERR(bh);
 567        }
 568
 569        while (size < newsize) {
 570                prev_bh = bh;
 571                bh = affs_getzeroblk_ino(inode, bidx);
 572                if (IS_ERR(bh))
 573                        goto out;
 574                tmp = min(bsize, newsize - size);
 575                BUG_ON(tmp > bsize);
 576                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 577                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 578                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 579                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 580                affs_fix_checksum(sb, bh);
 581                bh->b_state &= ~(1UL << BH_New);
 582                mark_buffer_dirty_inode(bh, inode);
 583                if (prev_bh) {
 584                        u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 585                        if (tmp)
 586                                affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
 587                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 588                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 589                        mark_buffer_dirty_inode(prev_bh, inode);
 590                        affs_brelse(prev_bh);
 591                }
 592                size += bsize;
 593                bidx++;
 594        }
 595        affs_brelse(bh);
 596        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 597        return 0;
 598
 599out:
 600        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 601        return PTR_ERR(bh);
 602}
 603
 604static int
 605affs_readpage_ofs(struct file *file, struct page *page)
 606{
 607        struct inode *inode = page->mapping->host;
 608        u32 to;
 609        int err;
 610
 611        pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
 612        to = PAGE_CACHE_SIZE;
 613        if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
 614                to = inode->i_size & ~PAGE_CACHE_MASK;
 615                memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
 616        }
 617
 618        err = affs_do_readpage_ofs(file, page, 0, to);
 619        if (!err)
 620                SetPageUptodate(page);
 621        unlock_page(page);
 622        return err;
 623}
 624
 625static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 626                                loff_t pos, unsigned len, unsigned flags,
 627                                struct page **pagep, void **fsdata)
 628{
 629        struct inode *inode = mapping->host;
 630        struct page *page;
 631        pgoff_t index;
 632        int err = 0;
 633
 634        pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 635        if (pos > AFFS_I(inode)->mmu_private) {
 636                /* XXX: this probably leaves a too-big i_size in case of
 637                 * failure. Should really be updating i_size at write_end time
 638                 */
 639                err = affs_extent_file_ofs(inode, pos);
 640                if (err)
 641                        return err;
 642        }
 643
 644        index = pos >> PAGE_CACHE_SHIFT;
 645        page = grab_cache_page_write_begin(mapping, index, flags);
 646        if (!page)
 647                return -ENOMEM;
 648        *pagep = page;
 649
 650        if (PageUptodate(page))
 651                return 0;
 652
 653        /* XXX: inefficient but safe in the face of short writes */
 654        err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
 655        if (err) {
 656                unlock_page(page);
 657                page_cache_release(page);
 658        }
 659        return err;
 660}
 661
 662static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 663                                loff_t pos, unsigned len, unsigned copied,
 664                                struct page *page, void *fsdata)
 665{
 666        struct inode *inode = mapping->host;
 667        struct super_block *sb = inode->i_sb;
 668        struct buffer_head *bh, *prev_bh;
 669        char *data;
 670        u32 bidx, boff, bsize;
 671        unsigned from, to;
 672        u32 tmp;
 673        int written;
 674
 675        from = pos & (PAGE_CACHE_SIZE - 1);
 676        to = pos + len;
 677        /*
 678         * XXX: not sure if this can handle short copies (len < copied), but
 679         * we don't have to, because the page should always be uptodate here,
 680         * due to write_begin.
 681         */
 682
 683        pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
 684        bsize = AFFS_SB(sb)->s_data_blksize;
 685        data = page_address(page);
 686
 687        bh = NULL;
 688        written = 0;
 689        tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 690        bidx = tmp / bsize;
 691        boff = tmp % bsize;
 692        if (boff) {
 693                bh = affs_bread_ino(inode, bidx, 0);
 694                if (IS_ERR(bh))
 695                        return PTR_ERR(bh);
 696                tmp = min(bsize - boff, to - from);
 697                BUG_ON(boff + tmp > bsize || tmp > bsize);
 698                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 699                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 700                affs_fix_checksum(sb, bh);
 701                mark_buffer_dirty_inode(bh, inode);
 702                written += tmp;
 703                from += tmp;
 704                bidx++;
 705        } else if (bidx) {
 706                bh = affs_bread_ino(inode, bidx - 1, 0);
 707                if (IS_ERR(bh))
 708                        return PTR_ERR(bh);
 709        }
 710        while (from + bsize <= to) {
 711                prev_bh = bh;
 712                bh = affs_getemptyblk_ino(inode, bidx);
 713                if (IS_ERR(bh))
 714                        goto out;
 715                memcpy(AFFS_DATA(bh), data + from, bsize);
 716                if (buffer_new(bh)) {
 717                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 718                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 719                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 720                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 721                        AFFS_DATA_HEAD(bh)->next = 0;
 722                        bh->b_state &= ~(1UL << BH_New);
 723                        if (prev_bh) {
 724                                u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 725                                if (tmp)
 726                                        affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 727                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 728                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 729                                mark_buffer_dirty_inode(prev_bh, inode);
 730                        }
 731                }
 732                affs_brelse(prev_bh);
 733                affs_fix_checksum(sb, bh);
 734                mark_buffer_dirty_inode(bh, inode);
 735                written += bsize;
 736                from += bsize;
 737                bidx++;
 738        }
 739        if (from < to) {
 740                prev_bh = bh;
 741                bh = affs_bread_ino(inode, bidx, 1);
 742                if (IS_ERR(bh))
 743                        goto out;
 744                tmp = min(bsize, to - from);
 745                BUG_ON(tmp > bsize);
 746                memcpy(AFFS_DATA(bh), data + from, tmp);
 747                if (buffer_new(bh)) {
 748                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 749                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 750                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 751                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 752                        AFFS_DATA_HEAD(bh)->next = 0;
 753                        bh->b_state &= ~(1UL << BH_New);
 754                        if (prev_bh) {
 755                                u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 756                                if (tmp)
 757                                        affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
 758                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 759                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
 760                                mark_buffer_dirty_inode(prev_bh, inode);
 761                        }
 762                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 763                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 764                affs_brelse(prev_bh);
 765                affs_fix_checksum(sb, bh);
 766                mark_buffer_dirty_inode(bh, inode);
 767                written += tmp;
 768                from += tmp;
 769                bidx++;
 770        }
 771        SetPageUptodate(page);
 772
 773done:
 774        affs_brelse(bh);
 775        tmp = (page->index << PAGE_CACHE_SHIFT) + from;
 776        if (tmp > inode->i_size)
 777                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 778
 779        unlock_page(page);
 780        page_cache_release(page);
 781
 782        return written;
 783
 784out:
 785        bh = prev_bh;
 786        if (!written)
 787                written = PTR_ERR(bh);
 788        goto done;
 789}
 790
 791const struct address_space_operations affs_aops_ofs = {
 792        .readpage = affs_readpage_ofs,
 793        //.writepage = affs_writepage_ofs,
 794        .write_begin = affs_write_begin_ofs,
 795        .write_end = affs_write_end_ofs
 796};
 797
 798/* Free any preallocated blocks. */
 799
 800void
 801affs_free_prealloc(struct inode *inode)
 802{
 803        struct super_block *sb = inode->i_sb;
 804
 805        pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
 806
 807        while (AFFS_I(inode)->i_pa_cnt) {
 808                AFFS_I(inode)->i_pa_cnt--;
 809                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 810        }
 811}
 812
 813/* Truncate (or enlarge) a file to the requested size. */
 814
 815void
 816affs_truncate(struct inode *inode)
 817{
 818        struct super_block *sb = inode->i_sb;
 819        u32 ext, ext_key;
 820        u32 last_blk, blkcnt, blk;
 821        u32 size;
 822        struct buffer_head *ext_bh;
 823        int i;
 824
 825        pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
 826                 (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
 827
 828        last_blk = 0;
 829        ext = 0;
 830        if (inode->i_size) {
 831                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 832                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 833        }
 834
 835        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 836                struct address_space *mapping = inode->i_mapping;
 837                struct page *page;
 838                void *fsdata;
 839                u32 size = inode->i_size;
 840                int res;
 841
 842                res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
 843                if (!res)
 844                        res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
 845                else
 846                        inode->i_size = AFFS_I(inode)->mmu_private;
 847                mark_inode_dirty(inode);
 848                return;
 849        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 850                return;
 851
 852        // lock cache
 853        ext_bh = affs_get_extblock(inode, ext);
 854        if (IS_ERR(ext_bh)) {
 855                affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
 856                             ext, PTR_ERR(ext_bh));
 857                return;
 858        }
 859        if (AFFS_I(inode)->i_lc) {
 860                /* clear linear cache */
 861                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 862                if (AFFS_I(inode)->i_lc_size > i) {
 863                        AFFS_I(inode)->i_lc_size = i;
 864                        for (; i < AFFS_LC_SIZE; i++)
 865                                AFFS_I(inode)->i_lc[i] = 0;
 866                }
 867                /* clear associative cache */
 868                for (i = 0; i < AFFS_AC_SIZE; i++)
 869                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 870                                AFFS_I(inode)->i_ac[i].ext = 0;
 871        }
 872        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 873
 874        blkcnt = AFFS_I(inode)->i_blkcnt;
 875        i = 0;
 876        blk = last_blk;
 877        if (inode->i_size) {
 878                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 879                blk++;
 880        } else
 881                AFFS_HEAD(ext_bh)->first_data = 0;
 882        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 883        size = AFFS_SB(sb)->s_hashsize;
 884        if (size > blkcnt - blk + i)
 885                size = blkcnt - blk + i;
 886        for (; i < size; i++, blk++) {
 887                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 888                AFFS_BLOCK(sb, ext_bh, i) = 0;
 889        }
 890        AFFS_TAIL(sb, ext_bh)->extension = 0;
 891        affs_fix_checksum(sb, ext_bh);
 892        mark_buffer_dirty_inode(ext_bh, inode);
 893        affs_brelse(ext_bh);
 894
 895        if (inode->i_size) {
 896                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 897                AFFS_I(inode)->i_extcnt = ext + 1;
 898                if (AFFS_SB(sb)->s_flags & SF_OFS) {
 899                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 900                        u32 tmp;
 901                        if (IS_ERR(bh)) {
 902                                affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
 903                                             ext, PTR_ERR(bh));
 904                                return;
 905                        }
 906                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 907                        AFFS_DATA_HEAD(bh)->next = 0;
 908                        affs_adjust_checksum(bh, -tmp);
 909                        affs_brelse(bh);
 910                }
 911        } else {
 912                AFFS_I(inode)->i_blkcnt = 0;
 913                AFFS_I(inode)->i_extcnt = 1;
 914        }
 915        AFFS_I(inode)->mmu_private = inode->i_size;
 916        // unlock cache
 917
 918        while (ext_key) {
 919                ext_bh = affs_bread(sb, ext_key);
 920                size = AFFS_SB(sb)->s_hashsize;
 921                if (size > blkcnt - blk)
 922                        size = blkcnt - blk;
 923                for (i = 0; i < size; i++, blk++)
 924                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 925                affs_free_block(sb, ext_key);
 926                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 927                affs_brelse(ext_bh);
 928        }
 929        affs_free_prealloc(inode);
 930}
 931
 932int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 933{
 934        struct inode *inode = filp->f_mapping->host;
 935        int ret, err;
 936
 937        err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 938        if (err)
 939                return err;
 940
 941        mutex_lock(&inode->i_mutex);
 942        ret = write_inode_now(inode, 0);
 943        err = sync_blockdev(inode->i_sb->s_bdev);
 944        if (!ret)
 945                ret = err;
 946        mutex_unlock(&inode->i_mutex);
 947        return ret;
 948}
 949
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