linux/fs/affs/file.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/affs/file.c
   4 *
   5 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   6 *
   7 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   8 *
   9 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
  10 *
  11 *  (C) 1991  Linus Torvalds - minix filesystem
  12 *
  13 *  affs regular file handling primitives
  14 */
  15
  16#include <linux/uio.h>
  17#include "affs.h"
  18
  19static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  20
  21static int
  22affs_file_open(struct inode *inode, struct file *filp)
  23{
  24        pr_debug("open(%lu,%d)\n",
  25                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  26        atomic_inc(&AFFS_I(inode)->i_opencnt);
  27        return 0;
  28}
  29
  30static int
  31affs_file_release(struct inode *inode, struct file *filp)
  32{
  33        pr_debug("release(%lu, %d)\n",
  34                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  35
  36        if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  37                inode_lock(inode);
  38                if (inode->i_size != AFFS_I(inode)->mmu_private)
  39                        affs_truncate(inode);
  40                affs_free_prealloc(inode);
  41                inode_unlock(inode);
  42        }
  43
  44        return 0;
  45}
  46
  47static int
  48affs_grow_extcache(struct inode *inode, u32 lc_idx)
  49{
  50        struct super_block      *sb = inode->i_sb;
  51        struct buffer_head      *bh;
  52        u32 lc_max;
  53        int i, j, key;
  54
  55        if (!AFFS_I(inode)->i_lc) {
  56                char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  57                if (!ptr)
  58                        return -ENOMEM;
  59                AFFS_I(inode)->i_lc = (u32 *)ptr;
  60                AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  61        }
  62
  63        lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  64
  65        if (AFFS_I(inode)->i_extcnt > lc_max) {
  66                u32 lc_shift, lc_mask, tmp, off;
  67
  68                /* need to recalculate linear cache, start from old size */
  69                lc_shift = AFFS_I(inode)->i_lc_shift;
  70                tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  71                for (; tmp; tmp >>= 1)
  72                        lc_shift++;
  73                lc_mask = (1 << lc_shift) - 1;
  74
  75                /* fix idx and old size to new shift */
  76                lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  77                AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  78
  79                /* first shrink old cache to make more space */
  80                off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  81                for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  82                        AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  83
  84                AFFS_I(inode)->i_lc_shift = lc_shift;
  85                AFFS_I(inode)->i_lc_mask = lc_mask;
  86        }
  87
  88        /* fill cache to the needed index */
  89        i = AFFS_I(inode)->i_lc_size;
  90        AFFS_I(inode)->i_lc_size = lc_idx + 1;
  91        for (; i <= lc_idx; i++) {
  92                if (!i) {
  93                        AFFS_I(inode)->i_lc[0] = inode->i_ino;
  94                        continue;
  95                }
  96                key = AFFS_I(inode)->i_lc[i - 1];
  97                j = AFFS_I(inode)->i_lc_mask + 1;
  98                // unlock cache
  99                for (; j > 0; j--) {
 100                        bh = affs_bread(sb, key);
 101                        if (!bh)
 102                                goto err;
 103                        key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 104                        affs_brelse(bh);
 105                }
 106                // lock cache
 107                AFFS_I(inode)->i_lc[i] = key;
 108        }
 109
 110        return 0;
 111
 112err:
 113        // lock cache
 114        return -EIO;
 115}
 116
 117static struct buffer_head *
 118affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 119{
 120        struct super_block *sb = inode->i_sb;
 121        struct buffer_head *new_bh;
 122        u32 blocknr, tmp;
 123
 124        blocknr = affs_alloc_block(inode, bh->b_blocknr);
 125        if (!blocknr)
 126                return ERR_PTR(-ENOSPC);
 127
 128        new_bh = affs_getzeroblk(sb, blocknr);
 129        if (!new_bh) {
 130                affs_free_block(sb, blocknr);
 131                return ERR_PTR(-EIO);
 132        }
 133
 134        AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 135        AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 136        AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 137        AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 138        affs_fix_checksum(sb, new_bh);
 139
 140        mark_buffer_dirty_inode(new_bh, inode);
 141
 142        tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 143        if (tmp)
 144                affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 145        AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 146        affs_adjust_checksum(bh, blocknr - tmp);
 147        mark_buffer_dirty_inode(bh, inode);
 148
 149        AFFS_I(inode)->i_extcnt++;
 150        mark_inode_dirty(inode);
 151
 152        return new_bh;
 153}
 154
 155static inline struct buffer_head *
 156affs_get_extblock(struct inode *inode, u32 ext)
 157{
 158        /* inline the simplest case: same extended block as last time */
 159        struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 160        if (ext == AFFS_I(inode)->i_ext_last)
 161                get_bh(bh);
 162        else
 163                /* we have to do more (not inlined) */
 164                bh = affs_get_extblock_slow(inode, ext);
 165
 166        return bh;
 167}
 168
 169static struct buffer_head *
 170affs_get_extblock_slow(struct inode *inode, u32 ext)
 171{
 172        struct super_block *sb = inode->i_sb;
 173        struct buffer_head *bh;
 174        u32 ext_key;
 175        u32 lc_idx, lc_off, ac_idx;
 176        u32 tmp, idx;
 177
 178        if (ext == AFFS_I(inode)->i_ext_last + 1) {
 179                /* read the next extended block from the current one */
 180                bh = AFFS_I(inode)->i_ext_bh;
 181                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 182                if (ext < AFFS_I(inode)->i_extcnt)
 183                        goto read_ext;
 184                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 185                bh = affs_alloc_extblock(inode, bh, ext);
 186                if (IS_ERR(bh))
 187                        return bh;
 188                goto store_ext;
 189        }
 190
 191        if (ext == 0) {
 192                /* we seek back to the file header block */
 193                ext_key = inode->i_ino;
 194                goto read_ext;
 195        }
 196
 197        if (ext >= AFFS_I(inode)->i_extcnt) {
 198                struct buffer_head *prev_bh;
 199
 200                /* allocate a new extended block */
 201                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 202
 203                /* get previous extended block */
 204                prev_bh = affs_get_extblock(inode, ext - 1);
 205                if (IS_ERR(prev_bh))
 206                        return prev_bh;
 207                bh = affs_alloc_extblock(inode, prev_bh, ext);
 208                affs_brelse(prev_bh);
 209                if (IS_ERR(bh))
 210                        return bh;
 211                goto store_ext;
 212        }
 213
 214again:
 215        /* check if there is an extended cache and whether it's large enough */
 216        lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 217        lc_off = ext & AFFS_I(inode)->i_lc_mask;
 218
 219        if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 220                int err;
 221
 222                err = affs_grow_extcache(inode, lc_idx);
 223                if (err)
 224                        return ERR_PTR(err);
 225                goto again;
 226        }
 227
 228        /* every n'th key we find in the linear cache */
 229        if (!lc_off) {
 230                ext_key = AFFS_I(inode)->i_lc[lc_idx];
 231                goto read_ext;
 232        }
 233
 234        /* maybe it's still in the associative cache */
 235        ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 236        if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 237                ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 238                goto read_ext;
 239        }
 240
 241        /* try to find one of the previous extended blocks */
 242        tmp = ext;
 243        idx = ac_idx;
 244        while (--tmp, --lc_off > 0) {
 245                idx = (idx - 1) & AFFS_AC_MASK;
 246                if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 247                        ext_key = AFFS_I(inode)->i_ac[idx].key;
 248                        goto find_ext;
 249                }
 250        }
 251
 252        /* fall back to the linear cache */
 253        ext_key = AFFS_I(inode)->i_lc[lc_idx];
 254find_ext:
 255        /* read all extended blocks until we find the one we need */
 256        //unlock cache
 257        do {
 258                bh = affs_bread(sb, ext_key);
 259                if (!bh)
 260                        goto err_bread;
 261                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 262                affs_brelse(bh);
 263                tmp++;
 264        } while (tmp < ext);
 265        //lock cache
 266
 267        /* store it in the associative cache */
 268        // recalculate ac_idx?
 269        AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 270        AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 271
 272read_ext:
 273        /* finally read the right extended block */
 274        //unlock cache
 275        bh = affs_bread(sb, ext_key);
 276        if (!bh)
 277                goto err_bread;
 278        //lock cache
 279
 280store_ext:
 281        /* release old cached extended block and store the new one */
 282        affs_brelse(AFFS_I(inode)->i_ext_bh);
 283        AFFS_I(inode)->i_ext_last = ext;
 284        AFFS_I(inode)->i_ext_bh = bh;
 285        get_bh(bh);
 286
 287        return bh;
 288
 289err_bread:
 290        affs_brelse(bh);
 291        return ERR_PTR(-EIO);
 292}
 293
 294static int
 295affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 296{
 297        struct super_block      *sb = inode->i_sb;
 298        struct buffer_head      *ext_bh;
 299        u32                      ext;
 300
 301        pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 302                 (unsigned long long)block);
 303
 304        BUG_ON(block > (sector_t)0x7fffffffUL);
 305
 306        if (block >= AFFS_I(inode)->i_blkcnt) {
 307                if (block > AFFS_I(inode)->i_blkcnt || !create)
 308                        goto err_big;
 309        } else
 310                create = 0;
 311
 312        //lock cache
 313        affs_lock_ext(inode);
 314
 315        ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 316        block -= ext * AFFS_SB(sb)->s_hashsize;
 317        ext_bh = affs_get_extblock(inode, ext);
 318        if (IS_ERR(ext_bh))
 319                goto err_ext;
 320        map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 321
 322        if (create) {
 323                u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 324                if (!blocknr)
 325                        goto err_alloc;
 326                set_buffer_new(bh_result);
 327                AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 328                AFFS_I(inode)->i_blkcnt++;
 329
 330                /* store new block */
 331                if (bh_result->b_blocknr)
 332                        affs_warning(sb, "get_block",
 333                                     "block already set (%llx)",
 334                                     (unsigned long long)bh_result->b_blocknr);
 335                AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 336                AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 337                affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 338                bh_result->b_blocknr = blocknr;
 339
 340                if (!block) {
 341                        /* insert first block into header block */
 342                        u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 343                        if (tmp)
 344                                affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 345                        AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 346                        affs_adjust_checksum(ext_bh, blocknr - tmp);
 347                }
 348        }
 349
 350        affs_brelse(ext_bh);
 351        //unlock cache
 352        affs_unlock_ext(inode);
 353        return 0;
 354
 355err_big:
 356        affs_error(inode->i_sb, "get_block", "strange block request %llu",
 357                   (unsigned long long)block);
 358        return -EIO;
 359err_ext:
 360        // unlock cache
 361        affs_unlock_ext(inode);
 362        return PTR_ERR(ext_bh);
 363err_alloc:
 364        brelse(ext_bh);
 365        clear_buffer_mapped(bh_result);
 366        bh_result->b_bdev = NULL;
 367        // unlock cache
 368        affs_unlock_ext(inode);
 369        return -ENOSPC;
 370}
 371
 372static int affs_writepage(struct page *page, struct writeback_control *wbc)
 373{
 374        return block_write_full_page(page, affs_get_block, wbc);
 375}
 376
 377static int affs_readpage(struct file *file, struct page *page)
 378{
 379        return block_read_full_page(page, affs_get_block);
 380}
 381
 382static void affs_write_failed(struct address_space *mapping, loff_t to)
 383{
 384        struct inode *inode = mapping->host;
 385
 386        if (to > inode->i_size) {
 387                truncate_pagecache(inode, inode->i_size);
 388                affs_truncate(inode);
 389        }
 390}
 391
 392static ssize_t
 393affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 394{
 395        struct file *file = iocb->ki_filp;
 396        struct address_space *mapping = file->f_mapping;
 397        struct inode *inode = mapping->host;
 398        size_t count = iov_iter_count(iter);
 399        loff_t offset = iocb->ki_pos;
 400        ssize_t ret;
 401
 402        if (iov_iter_rw(iter) == WRITE) {
 403                loff_t size = offset + count;
 404
 405                if (AFFS_I(inode)->mmu_private < size)
 406                        return 0;
 407        }
 408
 409        ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 410        if (ret < 0 && iov_iter_rw(iter) == WRITE)
 411                affs_write_failed(mapping, offset + count);
 412        return ret;
 413}
 414
 415static int affs_write_begin(struct file *file, struct address_space *mapping,
 416                        loff_t pos, unsigned len, unsigned flags,
 417                        struct page **pagep, void **fsdata)
 418{
 419        int ret;
 420
 421        *pagep = NULL;
 422        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 423                                affs_get_block,
 424                                &AFFS_I(mapping->host)->mmu_private);
 425        if (unlikely(ret))
 426                affs_write_failed(mapping, pos + len);
 427
 428        return ret;
 429}
 430
 431static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 432{
 433        return generic_block_bmap(mapping,block,affs_get_block);
 434}
 435
 436const struct address_space_operations affs_aops = {
 437        .readpage = affs_readpage,
 438        .writepage = affs_writepage,
 439        .write_begin = affs_write_begin,
 440        .write_end = generic_write_end,
 441        .direct_IO = affs_direct_IO,
 442        .bmap = _affs_bmap
 443};
 444
 445static inline struct buffer_head *
 446affs_bread_ino(struct inode *inode, int block, int create)
 447{
 448        struct buffer_head *bh, tmp_bh;
 449        int err;
 450
 451        tmp_bh.b_state = 0;
 452        err = affs_get_block(inode, block, &tmp_bh, create);
 453        if (!err) {
 454                bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 455                if (bh) {
 456                        bh->b_state |= tmp_bh.b_state;
 457                        return bh;
 458                }
 459                err = -EIO;
 460        }
 461        return ERR_PTR(err);
 462}
 463
 464static inline struct buffer_head *
 465affs_getzeroblk_ino(struct inode *inode, int block)
 466{
 467        struct buffer_head *bh, tmp_bh;
 468        int err;
 469
 470        tmp_bh.b_state = 0;
 471        err = affs_get_block(inode, block, &tmp_bh, 1);
 472        if (!err) {
 473                bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 474                if (bh) {
 475                        bh->b_state |= tmp_bh.b_state;
 476                        return bh;
 477                }
 478                err = -EIO;
 479        }
 480        return ERR_PTR(err);
 481}
 482
 483static inline struct buffer_head *
 484affs_getemptyblk_ino(struct inode *inode, int block)
 485{
 486        struct buffer_head *bh, tmp_bh;
 487        int err;
 488
 489        tmp_bh.b_state = 0;
 490        err = affs_get_block(inode, block, &tmp_bh, 1);
 491        if (!err) {
 492                bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 493                if (bh) {
 494                        bh->b_state |= tmp_bh.b_state;
 495                        return bh;
 496                }
 497                err = -EIO;
 498        }
 499        return ERR_PTR(err);
 500}
 501
 502static int
 503affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 504{
 505        struct inode *inode = page->mapping->host;
 506        struct super_block *sb = inode->i_sb;
 507        struct buffer_head *bh;
 508        char *data;
 509        unsigned pos = 0;
 510        u32 bidx, boff, bsize;
 511        u32 tmp;
 512
 513        pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 514                 page->index, to);
 515        BUG_ON(to > PAGE_SIZE);
 516        bsize = AFFS_SB(sb)->s_data_blksize;
 517        tmp = page->index << PAGE_SHIFT;
 518        bidx = tmp / bsize;
 519        boff = tmp % bsize;
 520
 521        while (pos < to) {
 522                bh = affs_bread_ino(inode, bidx, create);
 523                if (IS_ERR(bh))
 524                        return PTR_ERR(bh);
 525                tmp = min(bsize - boff, to - pos);
 526                BUG_ON(pos + tmp > to || tmp > bsize);
 527                data = kmap_atomic(page);
 528                memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 529                kunmap_atomic(data);
 530                affs_brelse(bh);
 531                bidx++;
 532                pos += tmp;
 533                boff = 0;
 534        }
 535        flush_dcache_page(page);
 536        return 0;
 537}
 538
 539static int
 540affs_extent_file_ofs(struct inode *inode, u32 newsize)
 541{
 542        struct super_block *sb = inode->i_sb;
 543        struct buffer_head *bh, *prev_bh;
 544        u32 bidx, boff;
 545        u32 size, bsize;
 546        u32 tmp;
 547
 548        pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 549        bsize = AFFS_SB(sb)->s_data_blksize;
 550        bh = NULL;
 551        size = AFFS_I(inode)->mmu_private;
 552        bidx = size / bsize;
 553        boff = size % bsize;
 554        if (boff) {
 555                bh = affs_bread_ino(inode, bidx, 0);
 556                if (IS_ERR(bh))
 557                        return PTR_ERR(bh);
 558                tmp = min(bsize - boff, newsize - size);
 559                BUG_ON(boff + tmp > bsize || tmp > bsize);
 560                memset(AFFS_DATA(bh) + boff, 0, tmp);
 561                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 562                affs_fix_checksum(sb, bh);
 563                mark_buffer_dirty_inode(bh, inode);
 564                size += tmp;
 565                bidx++;
 566        } else if (bidx) {
 567                bh = affs_bread_ino(inode, bidx - 1, 0);
 568                if (IS_ERR(bh))
 569                        return PTR_ERR(bh);
 570        }
 571
 572        while (size < newsize) {
 573                prev_bh = bh;
 574                bh = affs_getzeroblk_ino(inode, bidx);
 575                if (IS_ERR(bh))
 576                        goto out;
 577                tmp = min(bsize, newsize - size);
 578                BUG_ON(tmp > bsize);
 579                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 580                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 581                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 582                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 583                affs_fix_checksum(sb, bh);
 584                bh->b_state &= ~(1UL << BH_New);
 585                mark_buffer_dirty_inode(bh, inode);
 586                if (prev_bh) {
 587                        u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 588
 589                        if (tmp_next)
 590                                affs_warning(sb, "extent_file_ofs",
 591                                             "next block already set for %d (%d)",
 592                                             bidx, tmp_next);
 593                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 594                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 595                        mark_buffer_dirty_inode(prev_bh, inode);
 596                        affs_brelse(prev_bh);
 597                }
 598                size += bsize;
 599                bidx++;
 600        }
 601        affs_brelse(bh);
 602        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 603        return 0;
 604
 605out:
 606        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 607        return PTR_ERR(bh);
 608}
 609
 610static int
 611affs_readpage_ofs(struct file *file, struct page *page)
 612{
 613        struct inode *inode = page->mapping->host;
 614        u32 to;
 615        int err;
 616
 617        pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 618        to = PAGE_SIZE;
 619        if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 620                to = inode->i_size & ~PAGE_MASK;
 621                memset(page_address(page) + to, 0, PAGE_SIZE - to);
 622        }
 623
 624        err = affs_do_readpage_ofs(page, to, 0);
 625        if (!err)
 626                SetPageUptodate(page);
 627        unlock_page(page);
 628        return err;
 629}
 630
 631static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 632                                loff_t pos, unsigned len, unsigned flags,
 633                                struct page **pagep, void **fsdata)
 634{
 635        struct inode *inode = mapping->host;
 636        struct page *page;
 637        pgoff_t index;
 638        int err = 0;
 639
 640        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 641                 pos + len);
 642        if (pos > AFFS_I(inode)->mmu_private) {
 643                /* XXX: this probably leaves a too-big i_size in case of
 644                 * failure. Should really be updating i_size at write_end time
 645                 */
 646                err = affs_extent_file_ofs(inode, pos);
 647                if (err)
 648                        return err;
 649        }
 650
 651        index = pos >> PAGE_SHIFT;
 652        page = grab_cache_page_write_begin(mapping, index, flags);
 653        if (!page)
 654                return -ENOMEM;
 655        *pagep = page;
 656
 657        if (PageUptodate(page))
 658                return 0;
 659
 660        /* XXX: inefficient but safe in the face of short writes */
 661        err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 662        if (err) {
 663                unlock_page(page);
 664                put_page(page);
 665        }
 666        return err;
 667}
 668
 669static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 670                                loff_t pos, unsigned len, unsigned copied,
 671                                struct page *page, void *fsdata)
 672{
 673        struct inode *inode = mapping->host;
 674        struct super_block *sb = inode->i_sb;
 675        struct buffer_head *bh, *prev_bh;
 676        char *data;
 677        u32 bidx, boff, bsize;
 678        unsigned from, to;
 679        u32 tmp;
 680        int written;
 681
 682        from = pos & (PAGE_SIZE - 1);
 683        to = from + len;
 684        /*
 685         * XXX: not sure if this can handle short copies (len < copied), but
 686         * we don't have to, because the page should always be uptodate here,
 687         * due to write_begin.
 688         */
 689
 690        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 691                 pos + len);
 692        bsize = AFFS_SB(sb)->s_data_blksize;
 693        data = page_address(page);
 694
 695        bh = NULL;
 696        written = 0;
 697        tmp = (page->index << PAGE_SHIFT) + from;
 698        bidx = tmp / bsize;
 699        boff = tmp % bsize;
 700        if (boff) {
 701                bh = affs_bread_ino(inode, bidx, 0);
 702                if (IS_ERR(bh)) {
 703                        written = PTR_ERR(bh);
 704                        goto err_first_bh;
 705                }
 706                tmp = min(bsize - boff, to - from);
 707                BUG_ON(boff + tmp > bsize || tmp > bsize);
 708                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 709                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 710                affs_fix_checksum(sb, bh);
 711                mark_buffer_dirty_inode(bh, inode);
 712                written += tmp;
 713                from += tmp;
 714                bidx++;
 715        } else if (bidx) {
 716                bh = affs_bread_ino(inode, bidx - 1, 0);
 717                if (IS_ERR(bh)) {
 718                        written = PTR_ERR(bh);
 719                        goto err_first_bh;
 720                }
 721        }
 722        while (from + bsize <= to) {
 723                prev_bh = bh;
 724                bh = affs_getemptyblk_ino(inode, bidx);
 725                if (IS_ERR(bh))
 726                        goto err_bh;
 727                memcpy(AFFS_DATA(bh), data + from, bsize);
 728                if (buffer_new(bh)) {
 729                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 730                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 731                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 732                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 733                        AFFS_DATA_HEAD(bh)->next = 0;
 734                        bh->b_state &= ~(1UL << BH_New);
 735                        if (prev_bh) {
 736                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 737
 738                                if (tmp_next)
 739                                        affs_warning(sb, "commit_write_ofs",
 740                                                     "next block already set for %d (%d)",
 741                                                     bidx, tmp_next);
 742                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 743                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 744                                mark_buffer_dirty_inode(prev_bh, inode);
 745                        }
 746                }
 747                affs_brelse(prev_bh);
 748                affs_fix_checksum(sb, bh);
 749                mark_buffer_dirty_inode(bh, inode);
 750                written += bsize;
 751                from += bsize;
 752                bidx++;
 753        }
 754        if (from < to) {
 755                prev_bh = bh;
 756                bh = affs_bread_ino(inode, bidx, 1);
 757                if (IS_ERR(bh))
 758                        goto err_bh;
 759                tmp = min(bsize, to - from);
 760                BUG_ON(tmp > bsize);
 761                memcpy(AFFS_DATA(bh), data + from, tmp);
 762                if (buffer_new(bh)) {
 763                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 764                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 765                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 766                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 767                        AFFS_DATA_HEAD(bh)->next = 0;
 768                        bh->b_state &= ~(1UL << BH_New);
 769                        if (prev_bh) {
 770                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 771
 772                                if (tmp_next)
 773                                        affs_warning(sb, "commit_write_ofs",
 774                                                     "next block already set for %d (%d)",
 775                                                     bidx, tmp_next);
 776                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 777                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 778                                mark_buffer_dirty_inode(prev_bh, inode);
 779                        }
 780                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 781                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 782                affs_brelse(prev_bh);
 783                affs_fix_checksum(sb, bh);
 784                mark_buffer_dirty_inode(bh, inode);
 785                written += tmp;
 786                from += tmp;
 787                bidx++;
 788        }
 789        SetPageUptodate(page);
 790
 791done:
 792        affs_brelse(bh);
 793        tmp = (page->index << PAGE_SHIFT) + from;
 794        if (tmp > inode->i_size)
 795                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 796
 797err_first_bh:
 798        unlock_page(page);
 799        put_page(page);
 800
 801        return written;
 802
 803err_bh:
 804        bh = prev_bh;
 805        if (!written)
 806                written = PTR_ERR(bh);
 807        goto done;
 808}
 809
 810const struct address_space_operations affs_aops_ofs = {
 811        .readpage = affs_readpage_ofs,
 812        //.writepage = affs_writepage_ofs,
 813        .write_begin = affs_write_begin_ofs,
 814        .write_end = affs_write_end_ofs
 815};
 816
 817/* Free any preallocated blocks. */
 818
 819void
 820affs_free_prealloc(struct inode *inode)
 821{
 822        struct super_block *sb = inode->i_sb;
 823
 824        pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 825
 826        while (AFFS_I(inode)->i_pa_cnt) {
 827                AFFS_I(inode)->i_pa_cnt--;
 828                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 829        }
 830}
 831
 832/* Truncate (or enlarge) a file to the requested size. */
 833
 834void
 835affs_truncate(struct inode *inode)
 836{
 837        struct super_block *sb = inode->i_sb;
 838        u32 ext, ext_key;
 839        u32 last_blk, blkcnt, blk;
 840        u32 size;
 841        struct buffer_head *ext_bh;
 842        int i;
 843
 844        pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 845                 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 846
 847        last_blk = 0;
 848        ext = 0;
 849        if (inode->i_size) {
 850                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 851                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 852        }
 853
 854        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 855                struct address_space *mapping = inode->i_mapping;
 856                struct page *page;
 857                void *fsdata;
 858                loff_t isize = inode->i_size;
 859                int res;
 860
 861                res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 862                if (!res)
 863                        res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 864                else
 865                        inode->i_size = AFFS_I(inode)->mmu_private;
 866                mark_inode_dirty(inode);
 867                return;
 868        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 869                return;
 870
 871        // lock cache
 872        ext_bh = affs_get_extblock(inode, ext);
 873        if (IS_ERR(ext_bh)) {
 874                affs_warning(sb, "truncate",
 875                             "unexpected read error for ext block %u (%ld)",
 876                             ext, PTR_ERR(ext_bh));
 877                return;
 878        }
 879        if (AFFS_I(inode)->i_lc) {
 880                /* clear linear cache */
 881                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 882                if (AFFS_I(inode)->i_lc_size > i) {
 883                        AFFS_I(inode)->i_lc_size = i;
 884                        for (; i < AFFS_LC_SIZE; i++)
 885                                AFFS_I(inode)->i_lc[i] = 0;
 886                }
 887                /* clear associative cache */
 888                for (i = 0; i < AFFS_AC_SIZE; i++)
 889                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 890                                AFFS_I(inode)->i_ac[i].ext = 0;
 891        }
 892        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 893
 894        blkcnt = AFFS_I(inode)->i_blkcnt;
 895        i = 0;
 896        blk = last_blk;
 897        if (inode->i_size) {
 898                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 899                blk++;
 900        } else
 901                AFFS_HEAD(ext_bh)->first_data = 0;
 902        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 903        size = AFFS_SB(sb)->s_hashsize;
 904        if (size > blkcnt - blk + i)
 905                size = blkcnt - blk + i;
 906        for (; i < size; i++, blk++) {
 907                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 908                AFFS_BLOCK(sb, ext_bh, i) = 0;
 909        }
 910        AFFS_TAIL(sb, ext_bh)->extension = 0;
 911        affs_fix_checksum(sb, ext_bh);
 912        mark_buffer_dirty_inode(ext_bh, inode);
 913        affs_brelse(ext_bh);
 914
 915        if (inode->i_size) {
 916                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 917                AFFS_I(inode)->i_extcnt = ext + 1;
 918                if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 919                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 920                        u32 tmp;
 921                        if (IS_ERR(bh)) {
 922                                affs_warning(sb, "truncate",
 923                                             "unexpected read error for last block %u (%ld)",
 924                                             ext, PTR_ERR(bh));
 925                                return;
 926                        }
 927                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 928                        AFFS_DATA_HEAD(bh)->next = 0;
 929                        affs_adjust_checksum(bh, -tmp);
 930                        affs_brelse(bh);
 931                }
 932        } else {
 933                AFFS_I(inode)->i_blkcnt = 0;
 934                AFFS_I(inode)->i_extcnt = 1;
 935        }
 936        AFFS_I(inode)->mmu_private = inode->i_size;
 937        // unlock cache
 938
 939        while (ext_key) {
 940                ext_bh = affs_bread(sb, ext_key);
 941                size = AFFS_SB(sb)->s_hashsize;
 942                if (size > blkcnt - blk)
 943                        size = blkcnt - blk;
 944                for (i = 0; i < size; i++, blk++)
 945                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 946                affs_free_block(sb, ext_key);
 947                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 948                affs_brelse(ext_bh);
 949        }
 950        affs_free_prealloc(inode);
 951}
 952
 953int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 954{
 955        struct inode *inode = filp->f_mapping->host;
 956        int ret, err;
 957
 958        err = file_write_and_wait_range(filp, start, end);
 959        if (err)
 960                return err;
 961
 962        inode_lock(inode);
 963        ret = write_inode_now(inode, 0);
 964        err = sync_blockdev(inode->i_sb->s_bdev);
 965        if (!ret)
 966                ret = err;
 967        inode_unlock(inode);
 968        return ret;
 969}
 970const struct file_operations affs_file_operations = {
 971        .llseek         = generic_file_llseek,
 972        .read_iter      = generic_file_read_iter,
 973        .write_iter     = generic_file_write_iter,
 974        .mmap           = generic_file_mmap,
 975        .open           = affs_file_open,
 976        .release        = affs_file_release,
 977        .fsync          = affs_file_fsync,
 978        .splice_read    = generic_file_splice_read,
 979};
 980
 981const struct inode_operations affs_file_inode_operations = {
 982        .setattr        = affs_notify_change,
 983};
 984