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, loff_t offset)
 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        ssize_t ret;
 399
 400        if (iov_iter_rw(iter) == WRITE) {
 401                loff_t size = offset + count;
 402
 403                if (AFFS_I(inode)->mmu_private < size)
 404                        return 0;
 405        }
 406
 407        ret = blockdev_direct_IO(iocb, inode, iter, offset, affs_get_block);
 408        if (ret < 0 && iov_iter_rw(iter) == WRITE)
 409                affs_write_failed(mapping, offset + count);
 410        return ret;
 411}
 412
 413static int affs_write_begin(struct file *file, struct address_space *mapping,
 414                        loff_t pos, unsigned len, unsigned flags,
 415                        struct page **pagep, void **fsdata)
 416{
 417        int ret;
 418
 419        *pagep = NULL;
 420        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 421                                affs_get_block,
 422                                &AFFS_I(mapping->host)->mmu_private);
 423        if (unlikely(ret))
 424                affs_write_failed(mapping, pos + len);
 425
 426        return ret;
 427}
 428
 429static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 430{
 431        return generic_block_bmap(mapping,block,affs_get_block);
 432}
 433
 434const struct address_space_operations affs_aops = {
 435        .readpage = affs_readpage,
 436        .writepage = affs_writepage,
 437        .write_begin = affs_write_begin,
 438        .write_end = generic_write_end,
 439        .direct_IO = affs_direct_IO,
 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 page *page, 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        unsigned pos = 0;
 508        u32 bidx, boff, bsize;
 509        u32 tmp;
 510
 511        pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 512                 page->index, to);
 513        BUG_ON(to > PAGE_SIZE);
 514        bsize = AFFS_SB(sb)->s_data_blksize;
 515        tmp = page->index << PAGE_SHIFT;
 516        bidx = tmp / bsize;
 517        boff = tmp % bsize;
 518
 519        while (pos < 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 - pos);
 524                BUG_ON(pos + tmp > to || tmp > bsize);
 525                data = kmap_atomic(page);
 526                memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 527                kunmap_atomic(data);
 528                affs_brelse(bh);
 529                bidx++;
 530                pos += tmp;
 531                boff = 0;
 532        }
 533        flush_dcache_page(page);
 534        return 0;
 535}
 536
 537static int
 538affs_extent_file_ofs(struct inode *inode, u32 newsize)
 539{
 540        struct super_block *sb = inode->i_sb;
 541        struct buffer_head *bh, *prev_bh;
 542        u32 bidx, boff;
 543        u32 size, bsize;
 544        u32 tmp;
 545
 546        pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 547        bsize = AFFS_SB(sb)->s_data_blksize;
 548        bh = NULL;
 549        size = AFFS_I(inode)->mmu_private;
 550        bidx = size / bsize;
 551        boff = size % bsize;
 552        if (boff) {
 553                bh = affs_bread_ino(inode, bidx, 0);
 554                if (IS_ERR(bh))
 555                        return PTR_ERR(bh);
 556                tmp = min(bsize - boff, newsize - size);
 557                BUG_ON(boff + tmp > bsize || tmp > bsize);
 558                memset(AFFS_DATA(bh) + boff, 0, tmp);
 559                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 560                affs_fix_checksum(sb, bh);
 561                mark_buffer_dirty_inode(bh, inode);
 562                size += tmp;
 563                bidx++;
 564        } else if (bidx) {
 565                bh = affs_bread_ino(inode, bidx - 1, 0);
 566                if (IS_ERR(bh))
 567                        return PTR_ERR(bh);
 568        }
 569
 570        while (size < newsize) {
 571                prev_bh = bh;
 572                bh = affs_getzeroblk_ino(inode, bidx);
 573                if (IS_ERR(bh))
 574                        goto out;
 575                tmp = min(bsize, newsize - size);
 576                BUG_ON(tmp > bsize);
 577                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 578                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 579                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 580                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 581                affs_fix_checksum(sb, bh);
 582                bh->b_state &= ~(1UL << BH_New);
 583                mark_buffer_dirty_inode(bh, inode);
 584                if (prev_bh) {
 585                        u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 586
 587                        if (tmp_next)
 588                                affs_warning(sb, "extent_file_ofs",
 589                                             "next block already set for %d (%d)",
 590                                             bidx, tmp_next);
 591                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 592                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 593                        mark_buffer_dirty_inode(prev_bh, inode);
 594                        affs_brelse(prev_bh);
 595                }
 596                size += bsize;
 597                bidx++;
 598        }
 599        affs_brelse(bh);
 600        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 601        return 0;
 602
 603out:
 604        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 605        return PTR_ERR(bh);
 606}
 607
 608static int
 609affs_readpage_ofs(struct file *file, struct page *page)
 610{
 611        struct inode *inode = page->mapping->host;
 612        u32 to;
 613        int err;
 614
 615        pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 616        to = PAGE_SIZE;
 617        if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 618                to = inode->i_size & ~PAGE_MASK;
 619                memset(page_address(page) + to, 0, PAGE_SIZE - to);
 620        }
 621
 622        err = affs_do_readpage_ofs(page, to);
 623        if (!err)
 624                SetPageUptodate(page);
 625        unlock_page(page);
 626        return err;
 627}
 628
 629static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 630                                loff_t pos, unsigned len, unsigned flags,
 631                                struct page **pagep, void **fsdata)
 632{
 633        struct inode *inode = mapping->host;
 634        struct page *page;
 635        pgoff_t index;
 636        int err = 0;
 637
 638        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 639                 pos + len);
 640        if (pos > AFFS_I(inode)->mmu_private) {
 641                /* XXX: this probably leaves a too-big i_size in case of
 642                 * failure. Should really be updating i_size at write_end time
 643                 */
 644                err = affs_extent_file_ofs(inode, pos);
 645                if (err)
 646                        return err;
 647        }
 648
 649        index = pos >> PAGE_SHIFT;
 650        page = grab_cache_page_write_begin(mapping, index, flags);
 651        if (!page)
 652                return -ENOMEM;
 653        *pagep = page;
 654
 655        if (PageUptodate(page))
 656                return 0;
 657
 658        /* XXX: inefficient but safe in the face of short writes */
 659        err = affs_do_readpage_ofs(page, PAGE_SIZE);
 660        if (err) {
 661                unlock_page(page);
 662                put_page(page);
 663        }
 664        return err;
 665}
 666
 667static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 668                                loff_t pos, unsigned len, unsigned copied,
 669                                struct page *page, void *fsdata)
 670{
 671        struct inode *inode = mapping->host;
 672        struct super_block *sb = inode->i_sb;
 673        struct buffer_head *bh, *prev_bh;
 674        char *data;
 675        u32 bidx, boff, bsize;
 676        unsigned from, to;
 677        u32 tmp;
 678        int written;
 679
 680        from = pos & (PAGE_SIZE - 1);
 681        to = pos + len;
 682        /*
 683         * XXX: not sure if this can handle short copies (len < copied), but
 684         * we don't have to, because the page should always be uptodate here,
 685         * due to write_begin.
 686         */
 687
 688        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 689                 pos + len);
 690        bsize = AFFS_SB(sb)->s_data_blksize;
 691        data = page_address(page);
 692
 693        bh = NULL;
 694        written = 0;
 695        tmp = (page->index << PAGE_SHIFT) + from;
 696        bidx = tmp / bsize;
 697        boff = tmp % bsize;
 698        if (boff) {
 699                bh = affs_bread_ino(inode, bidx, 0);
 700                if (IS_ERR(bh)) {
 701                        written = PTR_ERR(bh);
 702                        goto err_first_bh;
 703                }
 704                tmp = min(bsize - boff, to - from);
 705                BUG_ON(boff + tmp > bsize || tmp > bsize);
 706                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 707                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 708                affs_fix_checksum(sb, bh);
 709                mark_buffer_dirty_inode(bh, inode);
 710                written += tmp;
 711                from += tmp;
 712                bidx++;
 713        } else if (bidx) {
 714                bh = affs_bread_ino(inode, bidx - 1, 0);
 715                if (IS_ERR(bh)) {
 716                        written = PTR_ERR(bh);
 717                        goto err_first_bh;
 718                }
 719        }
 720        while (from + bsize <= to) {
 721                prev_bh = bh;
 722                bh = affs_getemptyblk_ino(inode, bidx);
 723                if (IS_ERR(bh))
 724                        goto err_bh;
 725                memcpy(AFFS_DATA(bh), data + from, bsize);
 726                if (buffer_new(bh)) {
 727                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 728                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 729                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 730                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 731                        AFFS_DATA_HEAD(bh)->next = 0;
 732                        bh->b_state &= ~(1UL << BH_New);
 733                        if (prev_bh) {
 734                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 735
 736                                if (tmp_next)
 737                                        affs_warning(sb, "commit_write_ofs",
 738                                                     "next block already set for %d (%d)",
 739                                                     bidx, tmp_next);
 740                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 741                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 742                                mark_buffer_dirty_inode(prev_bh, inode);
 743                        }
 744                }
 745                affs_brelse(prev_bh);
 746                affs_fix_checksum(sb, bh);
 747                mark_buffer_dirty_inode(bh, inode);
 748                written += bsize;
 749                from += bsize;
 750                bidx++;
 751        }
 752        if (from < to) {
 753                prev_bh = bh;
 754                bh = affs_bread_ino(inode, bidx, 1);
 755                if (IS_ERR(bh))
 756                        goto err_bh;
 757                tmp = min(bsize, to - from);
 758                BUG_ON(tmp > bsize);
 759                memcpy(AFFS_DATA(bh), data + from, tmp);
 760                if (buffer_new(bh)) {
 761                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 762                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 763                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 764                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 765                        AFFS_DATA_HEAD(bh)->next = 0;
 766                        bh->b_state &= ~(1UL << BH_New);
 767                        if (prev_bh) {
 768                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 769
 770                                if (tmp_next)
 771                                        affs_warning(sb, "commit_write_ofs",
 772                                                     "next block already set for %d (%d)",
 773                                                     bidx, tmp_next);
 774                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 775                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 776                                mark_buffer_dirty_inode(prev_bh, inode);
 777                        }
 778                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 779                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 780                affs_brelse(prev_bh);
 781                affs_fix_checksum(sb, bh);
 782                mark_buffer_dirty_inode(bh, inode);
 783                written += tmp;
 784                from += tmp;
 785                bidx++;
 786        }
 787        SetPageUptodate(page);
 788
 789done:
 790        affs_brelse(bh);
 791        tmp = (page->index << PAGE_SHIFT) + from;
 792        if (tmp > inode->i_size)
 793                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 794
 795err_first_bh:
 796        unlock_page(page);
 797        put_page(page);
 798
 799        return written;
 800
 801err_bh:
 802        bh = prev_bh;
 803        if (!written)
 804                written = PTR_ERR(bh);
 805        goto done;
 806}
 807
 808const struct address_space_operations affs_aops_ofs = {
 809        .readpage = affs_readpage_ofs,
 810        //.writepage = affs_writepage_ofs,
 811        .write_begin = affs_write_begin_ofs,
 812        .write_end = affs_write_end_ofs
 813};
 814
 815/* Free any preallocated blocks. */
 816
 817void
 818affs_free_prealloc(struct inode *inode)
 819{
 820        struct super_block *sb = inode->i_sb;
 821
 822        pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 823
 824        while (AFFS_I(inode)->i_pa_cnt) {
 825                AFFS_I(inode)->i_pa_cnt--;
 826                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 827        }
 828}
 829
 830/* Truncate (or enlarge) a file to the requested size. */
 831
 832void
 833affs_truncate(struct inode *inode)
 834{
 835        struct super_block *sb = inode->i_sb;
 836        u32 ext, ext_key;
 837        u32 last_blk, blkcnt, blk;
 838        u32 size;
 839        struct buffer_head *ext_bh;
 840        int i;
 841
 842        pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 843                 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 844
 845        last_blk = 0;
 846        ext = 0;
 847        if (inode->i_size) {
 848                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 849                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 850        }
 851
 852        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 853                struct address_space *mapping = inode->i_mapping;
 854                struct page *page;
 855                void *fsdata;
 856                loff_t isize = inode->i_size;
 857                int res;
 858
 859                res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 860                if (!res)
 861                        res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 862                else
 863                        inode->i_size = AFFS_I(inode)->mmu_private;
 864                mark_inode_dirty(inode);
 865                return;
 866        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 867                return;
 868
 869        // lock cache
 870        ext_bh = affs_get_extblock(inode, ext);
 871        if (IS_ERR(ext_bh)) {
 872                affs_warning(sb, "truncate",
 873                             "unexpected read error for ext block %u (%ld)",
 874                             ext, PTR_ERR(ext_bh));
 875                return;
 876        }
 877        if (AFFS_I(inode)->i_lc) {
 878                /* clear linear cache */
 879                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 880                if (AFFS_I(inode)->i_lc_size > i) {
 881                        AFFS_I(inode)->i_lc_size = i;
 882                        for (; i < AFFS_LC_SIZE; i++)
 883                                AFFS_I(inode)->i_lc[i] = 0;
 884                }
 885                /* clear associative cache */
 886                for (i = 0; i < AFFS_AC_SIZE; i++)
 887                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 888                                AFFS_I(inode)->i_ac[i].ext = 0;
 889        }
 890        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 891
 892        blkcnt = AFFS_I(inode)->i_blkcnt;
 893        i = 0;
 894        blk = last_blk;
 895        if (inode->i_size) {
 896                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 897                blk++;
 898        } else
 899                AFFS_HEAD(ext_bh)->first_data = 0;
 900        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 901        size = AFFS_SB(sb)->s_hashsize;
 902        if (size > blkcnt - blk + i)
 903                size = blkcnt - blk + i;
 904        for (; i < size; i++, blk++) {
 905                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 906                AFFS_BLOCK(sb, ext_bh, i) = 0;
 907        }
 908        AFFS_TAIL(sb, ext_bh)->extension = 0;
 909        affs_fix_checksum(sb, ext_bh);
 910        mark_buffer_dirty_inode(ext_bh, inode);
 911        affs_brelse(ext_bh);
 912
 913        if (inode->i_size) {
 914                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 915                AFFS_I(inode)->i_extcnt = ext + 1;
 916                if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 917                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 918                        u32 tmp;
 919                        if (IS_ERR(bh)) {
 920                                affs_warning(sb, "truncate",
 921                                             "unexpected read error for last block %u (%ld)",
 922                                             ext, PTR_ERR(bh));
 923                                return;
 924                        }
 925                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 926                        AFFS_DATA_HEAD(bh)->next = 0;
 927                        affs_adjust_checksum(bh, -tmp);
 928                        affs_brelse(bh);
 929                }
 930        } else {
 931                AFFS_I(inode)->i_blkcnt = 0;
 932                AFFS_I(inode)->i_extcnt = 1;
 933        }
 934        AFFS_I(inode)->mmu_private = inode->i_size;
 935        // unlock cache
 936
 937        while (ext_key) {
 938                ext_bh = affs_bread(sb, ext_key);
 939                size = AFFS_SB(sb)->s_hashsize;
 940                if (size > blkcnt - blk)
 941                        size = blkcnt - blk;
 942                for (i = 0; i < size; i++, blk++)
 943                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 944                affs_free_block(sb, ext_key);
 945                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 946                affs_brelse(ext_bh);
 947        }
 948        affs_free_prealloc(inode);
 949}
 950
 951int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 952{
 953        struct inode *inode = filp->f_mapping->host;
 954        int ret, err;
 955
 956        err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 957        if (err)
 958                return err;
 959
 960        inode_lock(inode);
 961        ret = write_inode_now(inode, 0);
 962        err = sync_blockdev(inode->i_sb->s_bdev);
 963        if (!ret)
 964                ret = err;
 965        inode_unlock(inode);
 966        return ret;
 967}
 968const struct file_operations affs_file_operations = {
 969        .llseek         = generic_file_llseek,
 970        .read_iter      = generic_file_read_iter,
 971        .write_iter     = generic_file_write_iter,
 972        .mmap           = generic_file_mmap,
 973        .open           = affs_file_open,
 974        .release        = affs_file_release,
 975        .fsync          = affs_file_fsync,
 976        .splice_read    = generic_file_splice_read,
 977};
 978
 979const struct inode_operations affs_file_inode_operations = {
 980        .setattr        = affs_notify_change,
 981};
 982