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 <linux/blkdev.h>
  18#include "affs.h"
  19
  20static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  21
  22static int
  23affs_file_open(struct inode *inode, struct file *filp)
  24{
  25        pr_debug("open(%lu,%d)\n",
  26                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  27        atomic_inc(&AFFS_I(inode)->i_opencnt);
  28        return 0;
  29}
  30
  31static int
  32affs_file_release(struct inode *inode, struct file *filp)
  33{
  34        pr_debug("release(%lu, %d)\n",
  35                 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  36
  37        if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  38                inode_lock(inode);
  39                if (inode->i_size != AFFS_I(inode)->mmu_private)
  40                        affs_truncate(inode);
  41                affs_free_prealloc(inode);
  42                inode_unlock(inode);
  43        }
  44
  45        return 0;
  46}
  47
  48static int
  49affs_grow_extcache(struct inode *inode, u32 lc_idx)
  50{
  51        struct super_block      *sb = inode->i_sb;
  52        struct buffer_head      *bh;
  53        u32 lc_max;
  54        int i, j, key;
  55
  56        if (!AFFS_I(inode)->i_lc) {
  57                char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  58                if (!ptr)
  59                        return -ENOMEM;
  60                AFFS_I(inode)->i_lc = (u32 *)ptr;
  61                AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  62        }
  63
  64        lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  65
  66        if (AFFS_I(inode)->i_extcnt > lc_max) {
  67                u32 lc_shift, lc_mask, tmp, off;
  68
  69                /* need to recalculate linear cache, start from old size */
  70                lc_shift = AFFS_I(inode)->i_lc_shift;
  71                tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  72                for (; tmp; tmp >>= 1)
  73                        lc_shift++;
  74                lc_mask = (1 << lc_shift) - 1;
  75
  76                /* fix idx and old size to new shift */
  77                lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  78                AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79
  80                /* first shrink old cache to make more space */
  81                off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  82                for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  83                        AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  84
  85                AFFS_I(inode)->i_lc_shift = lc_shift;
  86                AFFS_I(inode)->i_lc_mask = lc_mask;
  87        }
  88
  89        /* fill cache to the needed index */
  90        i = AFFS_I(inode)->i_lc_size;
  91        AFFS_I(inode)->i_lc_size = lc_idx + 1;
  92        for (; i <= lc_idx; i++) {
  93                if (!i) {
  94                        AFFS_I(inode)->i_lc[0] = inode->i_ino;
  95                        continue;
  96                }
  97                key = AFFS_I(inode)->i_lc[i - 1];
  98                j = AFFS_I(inode)->i_lc_mask + 1;
  99                // unlock cache
 100                for (; j > 0; j--) {
 101                        bh = affs_bread(sb, key);
 102                        if (!bh)
 103                                goto err;
 104                        key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 105                        affs_brelse(bh);
 106                }
 107                // lock cache
 108                AFFS_I(inode)->i_lc[i] = key;
 109        }
 110
 111        return 0;
 112
 113err:
 114        // lock cache
 115        return -EIO;
 116}
 117
 118static struct buffer_head *
 119affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 120{
 121        struct super_block *sb = inode->i_sb;
 122        struct buffer_head *new_bh;
 123        u32 blocknr, tmp;
 124
 125        blocknr = affs_alloc_block(inode, bh->b_blocknr);
 126        if (!blocknr)
 127                return ERR_PTR(-ENOSPC);
 128
 129        new_bh = affs_getzeroblk(sb, blocknr);
 130        if (!new_bh) {
 131                affs_free_block(sb, blocknr);
 132                return ERR_PTR(-EIO);
 133        }
 134
 135        AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 136        AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 137        AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 138        AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 139        affs_fix_checksum(sb, new_bh);
 140
 141        mark_buffer_dirty_inode(new_bh, inode);
 142
 143        tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 144        if (tmp)
 145                affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 146        AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 147        affs_adjust_checksum(bh, blocknr - tmp);
 148        mark_buffer_dirty_inode(bh, inode);
 149
 150        AFFS_I(inode)->i_extcnt++;
 151        mark_inode_dirty(inode);
 152
 153        return new_bh;
 154}
 155
 156static inline struct buffer_head *
 157affs_get_extblock(struct inode *inode, u32 ext)
 158{
 159        /* inline the simplest case: same extended block as last time */
 160        struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 161        if (ext == AFFS_I(inode)->i_ext_last)
 162                get_bh(bh);
 163        else
 164                /* we have to do more (not inlined) */
 165                bh = affs_get_extblock_slow(inode, ext);
 166
 167        return bh;
 168}
 169
 170static struct buffer_head *
 171affs_get_extblock_slow(struct inode *inode, u32 ext)
 172{
 173        struct super_block *sb = inode->i_sb;
 174        struct buffer_head *bh;
 175        u32 ext_key;
 176        u32 lc_idx, lc_off, ac_idx;
 177        u32 tmp, idx;
 178
 179        if (ext == AFFS_I(inode)->i_ext_last + 1) {
 180                /* read the next extended block from the current one */
 181                bh = AFFS_I(inode)->i_ext_bh;
 182                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 183                if (ext < AFFS_I(inode)->i_extcnt)
 184                        goto read_ext;
 185                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 186                bh = affs_alloc_extblock(inode, bh, ext);
 187                if (IS_ERR(bh))
 188                        return bh;
 189                goto store_ext;
 190        }
 191
 192        if (ext == 0) {
 193                /* we seek back to the file header block */
 194                ext_key = inode->i_ino;
 195                goto read_ext;
 196        }
 197
 198        if (ext >= AFFS_I(inode)->i_extcnt) {
 199                struct buffer_head *prev_bh;
 200
 201                /* allocate a new extended block */
 202                BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 203
 204                /* get previous extended block */
 205                prev_bh = affs_get_extblock(inode, ext - 1);
 206                if (IS_ERR(prev_bh))
 207                        return prev_bh;
 208                bh = affs_alloc_extblock(inode, prev_bh, ext);
 209                affs_brelse(prev_bh);
 210                if (IS_ERR(bh))
 211                        return bh;
 212                goto store_ext;
 213        }
 214
 215again:
 216        /* check if there is an extended cache and whether it's large enough */
 217        lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 218        lc_off = ext & AFFS_I(inode)->i_lc_mask;
 219
 220        if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 221                int err;
 222
 223                err = affs_grow_extcache(inode, lc_idx);
 224                if (err)
 225                        return ERR_PTR(err);
 226                goto again;
 227        }
 228
 229        /* every n'th key we find in the linear cache */
 230        if (!lc_off) {
 231                ext_key = AFFS_I(inode)->i_lc[lc_idx];
 232                goto read_ext;
 233        }
 234
 235        /* maybe it's still in the associative cache */
 236        ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 237        if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 238                ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 239                goto read_ext;
 240        }
 241
 242        /* try to find one of the previous extended blocks */
 243        tmp = ext;
 244        idx = ac_idx;
 245        while (--tmp, --lc_off > 0) {
 246                idx = (idx - 1) & AFFS_AC_MASK;
 247                if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 248                        ext_key = AFFS_I(inode)->i_ac[idx].key;
 249                        goto find_ext;
 250                }
 251        }
 252
 253        /* fall back to the linear cache */
 254        ext_key = AFFS_I(inode)->i_lc[lc_idx];
 255find_ext:
 256        /* read all extended blocks until we find the one we need */
 257        //unlock cache
 258        do {
 259                bh = affs_bread(sb, ext_key);
 260                if (!bh)
 261                        goto err_bread;
 262                ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 263                affs_brelse(bh);
 264                tmp++;
 265        } while (tmp < ext);
 266        //lock cache
 267
 268        /* store it in the associative cache */
 269        // recalculate ac_idx?
 270        AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 271        AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 272
 273read_ext:
 274        /* finally read the right extended block */
 275        //unlock cache
 276        bh = affs_bread(sb, ext_key);
 277        if (!bh)
 278                goto err_bread;
 279        //lock cache
 280
 281store_ext:
 282        /* release old cached extended block and store the new one */
 283        affs_brelse(AFFS_I(inode)->i_ext_bh);
 284        AFFS_I(inode)->i_ext_last = ext;
 285        AFFS_I(inode)->i_ext_bh = bh;
 286        get_bh(bh);
 287
 288        return bh;
 289
 290err_bread:
 291        affs_brelse(bh);
 292        return ERR_PTR(-EIO);
 293}
 294
 295static int
 296affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 297{
 298        struct super_block      *sb = inode->i_sb;
 299        struct buffer_head      *ext_bh;
 300        u32                      ext;
 301
 302        pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 303                 (unsigned long long)block);
 304
 305        BUG_ON(block > (sector_t)0x7fffffffUL);
 306
 307        if (block >= AFFS_I(inode)->i_blkcnt) {
 308                if (block > AFFS_I(inode)->i_blkcnt || !create)
 309                        goto err_big;
 310        } else
 311                create = 0;
 312
 313        //lock cache
 314        affs_lock_ext(inode);
 315
 316        ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 317        block -= ext * AFFS_SB(sb)->s_hashsize;
 318        ext_bh = affs_get_extblock(inode, ext);
 319        if (IS_ERR(ext_bh))
 320                goto err_ext;
 321        map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 322
 323        if (create) {
 324                u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 325                if (!blocknr)
 326                        goto err_alloc;
 327                set_buffer_new(bh_result);
 328                AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 329                AFFS_I(inode)->i_blkcnt++;
 330
 331                /* store new block */
 332                if (bh_result->b_blocknr)
 333                        affs_warning(sb, "get_block",
 334                                     "block already set (%llx)",
 335                                     (unsigned long long)bh_result->b_blocknr);
 336                AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 337                AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 338                affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 339                bh_result->b_blocknr = blocknr;
 340
 341                if (!block) {
 342                        /* insert first block into header block */
 343                        u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 344                        if (tmp)
 345                                affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 346                        AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 347                        affs_adjust_checksum(ext_bh, blocknr - tmp);
 348                }
 349        }
 350
 351        affs_brelse(ext_bh);
 352        //unlock cache
 353        affs_unlock_ext(inode);
 354        return 0;
 355
 356err_big:
 357        affs_error(inode->i_sb, "get_block", "strange block request %llu",
 358                   (unsigned long long)block);
 359        return -EIO;
 360err_ext:
 361        // unlock cache
 362        affs_unlock_ext(inode);
 363        return PTR_ERR(ext_bh);
 364err_alloc:
 365        brelse(ext_bh);
 366        clear_buffer_mapped(bh_result);
 367        bh_result->b_bdev = NULL;
 368        // unlock cache
 369        affs_unlock_ext(inode);
 370        return -ENOSPC;
 371}
 372
 373static int affs_writepage(struct page *page, struct writeback_control *wbc)
 374{
 375        return block_write_full_page(page, affs_get_block, wbc);
 376}
 377
 378static int affs_readpage(struct file *file, struct page *page)
 379{
 380        return block_read_full_page(page, affs_get_block);
 381}
 382
 383static void affs_write_failed(struct address_space *mapping, loff_t to)
 384{
 385        struct inode *inode = mapping->host;
 386
 387        if (to > inode->i_size) {
 388                truncate_pagecache(inode, inode->i_size);
 389                affs_truncate(inode);
 390        }
 391}
 392
 393static ssize_t
 394affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 395{
 396        struct file *file = iocb->ki_filp;
 397        struct address_space *mapping = file->f_mapping;
 398        struct inode *inode = mapping->host;
 399        size_t count = iov_iter_count(iter);
 400        loff_t offset = iocb->ki_pos;
 401        ssize_t ret;
 402
 403        if (iov_iter_rw(iter) == WRITE) {
 404                loff_t size = offset + count;
 405
 406                if (AFFS_I(inode)->mmu_private < size)
 407                        return 0;
 408        }
 409
 410        ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 411        if (ret < 0 && iov_iter_rw(iter) == WRITE)
 412                affs_write_failed(mapping, offset + count);
 413        return ret;
 414}
 415
 416static int affs_write_begin(struct file *file, struct address_space *mapping,
 417                        loff_t pos, unsigned len, unsigned flags,
 418                        struct page **pagep, void **fsdata)
 419{
 420        int ret;
 421
 422        *pagep = NULL;
 423        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 424                                affs_get_block,
 425                                &AFFS_I(mapping->host)->mmu_private);
 426        if (unlikely(ret))
 427                affs_write_failed(mapping, pos + len);
 428
 429        return ret;
 430}
 431
 432static int affs_write_end(struct file *file, struct address_space *mapping,
 433                          loff_t pos, unsigned int len, unsigned int copied,
 434                          struct page *page, void *fsdata)
 435{
 436        struct inode *inode = mapping->host;
 437        int ret;
 438
 439        ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 440
 441        /* Clear Archived bit on file writes, as AmigaOS would do */
 442        if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 443                AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 444                mark_inode_dirty(inode);
 445        }
 446
 447        return ret;
 448}
 449
 450static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 451{
 452        return generic_block_bmap(mapping,block,affs_get_block);
 453}
 454
 455const struct address_space_operations affs_aops = {
 456        .set_page_dirty = __set_page_dirty_buffers,
 457        .readpage = affs_readpage,
 458        .writepage = affs_writepage,
 459        .write_begin = affs_write_begin,
 460        .write_end = affs_write_end,
 461        .direct_IO = affs_direct_IO,
 462        .bmap = _affs_bmap
 463};
 464
 465static inline struct buffer_head *
 466affs_bread_ino(struct inode *inode, int block, int create)
 467{
 468        struct buffer_head *bh, tmp_bh;
 469        int err;
 470
 471        tmp_bh.b_state = 0;
 472        err = affs_get_block(inode, block, &tmp_bh, create);
 473        if (!err) {
 474                bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 475                if (bh) {
 476                        bh->b_state |= tmp_bh.b_state;
 477                        return bh;
 478                }
 479                err = -EIO;
 480        }
 481        return ERR_PTR(err);
 482}
 483
 484static inline struct buffer_head *
 485affs_getzeroblk_ino(struct inode *inode, int block)
 486{
 487        struct buffer_head *bh, tmp_bh;
 488        int err;
 489
 490        tmp_bh.b_state = 0;
 491        err = affs_get_block(inode, block, &tmp_bh, 1);
 492        if (!err) {
 493                bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 494                if (bh) {
 495                        bh->b_state |= tmp_bh.b_state;
 496                        return bh;
 497                }
 498                err = -EIO;
 499        }
 500        return ERR_PTR(err);
 501}
 502
 503static inline struct buffer_head *
 504affs_getemptyblk_ino(struct inode *inode, int block)
 505{
 506        struct buffer_head *bh, tmp_bh;
 507        int err;
 508
 509        tmp_bh.b_state = 0;
 510        err = affs_get_block(inode, block, &tmp_bh, 1);
 511        if (!err) {
 512                bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 513                if (bh) {
 514                        bh->b_state |= tmp_bh.b_state;
 515                        return bh;
 516                }
 517                err = -EIO;
 518        }
 519        return ERR_PTR(err);
 520}
 521
 522static int
 523affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 524{
 525        struct inode *inode = page->mapping->host;
 526        struct super_block *sb = inode->i_sb;
 527        struct buffer_head *bh;
 528        char *data;
 529        unsigned pos = 0;
 530        u32 bidx, boff, bsize;
 531        u32 tmp;
 532
 533        pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 534                 page->index, to);
 535        BUG_ON(to > PAGE_SIZE);
 536        bsize = AFFS_SB(sb)->s_data_blksize;
 537        tmp = page->index << PAGE_SHIFT;
 538        bidx = tmp / bsize;
 539        boff = tmp % bsize;
 540
 541        while (pos < to) {
 542                bh = affs_bread_ino(inode, bidx, create);
 543                if (IS_ERR(bh))
 544                        return PTR_ERR(bh);
 545                tmp = min(bsize - boff, to - pos);
 546                BUG_ON(pos + tmp > to || tmp > bsize);
 547                data = kmap_atomic(page);
 548                memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 549                kunmap_atomic(data);
 550                affs_brelse(bh);
 551                bidx++;
 552                pos += tmp;
 553                boff = 0;
 554        }
 555        flush_dcache_page(page);
 556        return 0;
 557}
 558
 559static int
 560affs_extent_file_ofs(struct inode *inode, u32 newsize)
 561{
 562        struct super_block *sb = inode->i_sb;
 563        struct buffer_head *bh, *prev_bh;
 564        u32 bidx, boff;
 565        u32 size, bsize;
 566        u32 tmp;
 567
 568        pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 569        bsize = AFFS_SB(sb)->s_data_blksize;
 570        bh = NULL;
 571        size = AFFS_I(inode)->mmu_private;
 572        bidx = size / bsize;
 573        boff = size % bsize;
 574        if (boff) {
 575                bh = affs_bread_ino(inode, bidx, 0);
 576                if (IS_ERR(bh))
 577                        return PTR_ERR(bh);
 578                tmp = min(bsize - boff, newsize - size);
 579                BUG_ON(boff + tmp > bsize || tmp > bsize);
 580                memset(AFFS_DATA(bh) + boff, 0, tmp);
 581                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 582                affs_fix_checksum(sb, bh);
 583                mark_buffer_dirty_inode(bh, inode);
 584                size += tmp;
 585                bidx++;
 586        } else if (bidx) {
 587                bh = affs_bread_ino(inode, bidx - 1, 0);
 588                if (IS_ERR(bh))
 589                        return PTR_ERR(bh);
 590        }
 591
 592        while (size < newsize) {
 593                prev_bh = bh;
 594                bh = affs_getzeroblk_ino(inode, bidx);
 595                if (IS_ERR(bh))
 596                        goto out;
 597                tmp = min(bsize, newsize - size);
 598                BUG_ON(tmp > bsize);
 599                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 600                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 601                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 602                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 603                affs_fix_checksum(sb, bh);
 604                bh->b_state &= ~(1UL << BH_New);
 605                mark_buffer_dirty_inode(bh, inode);
 606                if (prev_bh) {
 607                        u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 608
 609                        if (tmp_next)
 610                                affs_warning(sb, "extent_file_ofs",
 611                                             "next block already set for %d (%d)",
 612                                             bidx, tmp_next);
 613                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 614                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 615                        mark_buffer_dirty_inode(prev_bh, inode);
 616                        affs_brelse(prev_bh);
 617                }
 618                size += bsize;
 619                bidx++;
 620        }
 621        affs_brelse(bh);
 622        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 623        return 0;
 624
 625out:
 626        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 627        return PTR_ERR(bh);
 628}
 629
 630static int
 631affs_readpage_ofs(struct file *file, struct page *page)
 632{
 633        struct inode *inode = page->mapping->host;
 634        u32 to;
 635        int err;
 636
 637        pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 638        to = PAGE_SIZE;
 639        if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 640                to = inode->i_size & ~PAGE_MASK;
 641                memset(page_address(page) + to, 0, PAGE_SIZE - to);
 642        }
 643
 644        err = affs_do_readpage_ofs(page, to, 0);
 645        if (!err)
 646                SetPageUptodate(page);
 647        unlock_page(page);
 648        return err;
 649}
 650
 651static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 652                                loff_t pos, unsigned len, unsigned flags,
 653                                struct page **pagep, void **fsdata)
 654{
 655        struct inode *inode = mapping->host;
 656        struct page *page;
 657        pgoff_t index;
 658        int err = 0;
 659
 660        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 661                 pos + len);
 662        if (pos > AFFS_I(inode)->mmu_private) {
 663                /* XXX: this probably leaves a too-big i_size in case of
 664                 * failure. Should really be updating i_size at write_end time
 665                 */
 666                err = affs_extent_file_ofs(inode, pos);
 667                if (err)
 668                        return err;
 669        }
 670
 671        index = pos >> PAGE_SHIFT;
 672        page = grab_cache_page_write_begin(mapping, index, flags);
 673        if (!page)
 674                return -ENOMEM;
 675        *pagep = page;
 676
 677        if (PageUptodate(page))
 678                return 0;
 679
 680        /* XXX: inefficient but safe in the face of short writes */
 681        err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 682        if (err) {
 683                unlock_page(page);
 684                put_page(page);
 685        }
 686        return err;
 687}
 688
 689static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 690                                loff_t pos, unsigned len, unsigned copied,
 691                                struct page *page, void *fsdata)
 692{
 693        struct inode *inode = mapping->host;
 694        struct super_block *sb = inode->i_sb;
 695        struct buffer_head *bh, *prev_bh;
 696        char *data;
 697        u32 bidx, boff, bsize;
 698        unsigned from, to;
 699        u32 tmp;
 700        int written;
 701
 702        from = pos & (PAGE_SIZE - 1);
 703        to = from + len;
 704        /*
 705         * XXX: not sure if this can handle short copies (len < copied), but
 706         * we don't have to, because the page should always be uptodate here,
 707         * due to write_begin.
 708         */
 709
 710        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 711                 pos + len);
 712        bsize = AFFS_SB(sb)->s_data_blksize;
 713        data = page_address(page);
 714
 715        bh = NULL;
 716        written = 0;
 717        tmp = (page->index << PAGE_SHIFT) + from;
 718        bidx = tmp / bsize;
 719        boff = tmp % bsize;
 720        if (boff) {
 721                bh = affs_bread_ino(inode, bidx, 0);
 722                if (IS_ERR(bh)) {
 723                        written = PTR_ERR(bh);
 724                        goto err_first_bh;
 725                }
 726                tmp = min(bsize - boff, to - from);
 727                BUG_ON(boff + tmp > bsize || tmp > bsize);
 728                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 729                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 730                affs_fix_checksum(sb, bh);
 731                mark_buffer_dirty_inode(bh, inode);
 732                written += tmp;
 733                from += tmp;
 734                bidx++;
 735        } else if (bidx) {
 736                bh = affs_bread_ino(inode, bidx - 1, 0);
 737                if (IS_ERR(bh)) {
 738                        written = PTR_ERR(bh);
 739                        goto err_first_bh;
 740                }
 741        }
 742        while (from + bsize <= to) {
 743                prev_bh = bh;
 744                bh = affs_getemptyblk_ino(inode, bidx);
 745                if (IS_ERR(bh))
 746                        goto err_bh;
 747                memcpy(AFFS_DATA(bh), data + from, bsize);
 748                if (buffer_new(bh)) {
 749                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 750                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 751                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 752                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 753                        AFFS_DATA_HEAD(bh)->next = 0;
 754                        bh->b_state &= ~(1UL << BH_New);
 755                        if (prev_bh) {
 756                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 757
 758                                if (tmp_next)
 759                                        affs_warning(sb, "commit_write_ofs",
 760                                                     "next block already set for %d (%d)",
 761                                                     bidx, tmp_next);
 762                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 763                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 764                                mark_buffer_dirty_inode(prev_bh, inode);
 765                        }
 766                }
 767                affs_brelse(prev_bh);
 768                affs_fix_checksum(sb, bh);
 769                mark_buffer_dirty_inode(bh, inode);
 770                written += bsize;
 771                from += bsize;
 772                bidx++;
 773        }
 774        if (from < to) {
 775                prev_bh = bh;
 776                bh = affs_bread_ino(inode, bidx, 1);
 777                if (IS_ERR(bh))
 778                        goto err_bh;
 779                tmp = min(bsize, to - from);
 780                BUG_ON(tmp > bsize);
 781                memcpy(AFFS_DATA(bh), data + from, tmp);
 782                if (buffer_new(bh)) {
 783                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 784                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 785                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 786                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 787                        AFFS_DATA_HEAD(bh)->next = 0;
 788                        bh->b_state &= ~(1UL << BH_New);
 789                        if (prev_bh) {
 790                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 791
 792                                if (tmp_next)
 793                                        affs_warning(sb, "commit_write_ofs",
 794                                                     "next block already set for %d (%d)",
 795                                                     bidx, tmp_next);
 796                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 797                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 798                                mark_buffer_dirty_inode(prev_bh, inode);
 799                        }
 800                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 801                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 802                affs_brelse(prev_bh);
 803                affs_fix_checksum(sb, bh);
 804                mark_buffer_dirty_inode(bh, inode);
 805                written += tmp;
 806                from += tmp;
 807                bidx++;
 808        }
 809        SetPageUptodate(page);
 810
 811done:
 812        affs_brelse(bh);
 813        tmp = (page->index << PAGE_SHIFT) + from;
 814        if (tmp > inode->i_size)
 815                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 816
 817        /* Clear Archived bit on file writes, as AmigaOS would do */
 818        if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 819                AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 820                mark_inode_dirty(inode);
 821        }
 822
 823err_first_bh:
 824        unlock_page(page);
 825        put_page(page);
 826
 827        return written;
 828
 829err_bh:
 830        bh = prev_bh;
 831        if (!written)
 832                written = PTR_ERR(bh);
 833        goto done;
 834}
 835
 836const struct address_space_operations affs_aops_ofs = {
 837        .set_page_dirty = __set_page_dirty_buffers,
 838        .readpage = affs_readpage_ofs,
 839        //.writepage = affs_writepage_ofs,
 840        .write_begin = affs_write_begin_ofs,
 841        .write_end = affs_write_end_ofs
 842};
 843
 844/* Free any preallocated blocks. */
 845
 846void
 847affs_free_prealloc(struct inode *inode)
 848{
 849        struct super_block *sb = inode->i_sb;
 850
 851        pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 852
 853        while (AFFS_I(inode)->i_pa_cnt) {
 854                AFFS_I(inode)->i_pa_cnt--;
 855                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 856        }
 857}
 858
 859/* Truncate (or enlarge) a file to the requested size. */
 860
 861void
 862affs_truncate(struct inode *inode)
 863{
 864        struct super_block *sb = inode->i_sb;
 865        u32 ext, ext_key;
 866        u32 last_blk, blkcnt, blk;
 867        u32 size;
 868        struct buffer_head *ext_bh;
 869        int i;
 870
 871        pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 872                 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 873
 874        last_blk = 0;
 875        ext = 0;
 876        if (inode->i_size) {
 877                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 878                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 879        }
 880
 881        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 882                struct address_space *mapping = inode->i_mapping;
 883                struct page *page;
 884                void *fsdata;
 885                loff_t isize = inode->i_size;
 886                int res;
 887
 888                res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 889                if (!res)
 890                        res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 891                else
 892                        inode->i_size = AFFS_I(inode)->mmu_private;
 893                mark_inode_dirty(inode);
 894                return;
 895        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 896                return;
 897
 898        // lock cache
 899        ext_bh = affs_get_extblock(inode, ext);
 900        if (IS_ERR(ext_bh)) {
 901                affs_warning(sb, "truncate",
 902                             "unexpected read error for ext block %u (%ld)",
 903                             ext, PTR_ERR(ext_bh));
 904                return;
 905        }
 906        if (AFFS_I(inode)->i_lc) {
 907                /* clear linear cache */
 908                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 909                if (AFFS_I(inode)->i_lc_size > i) {
 910                        AFFS_I(inode)->i_lc_size = i;
 911                        for (; i < AFFS_LC_SIZE; i++)
 912                                AFFS_I(inode)->i_lc[i] = 0;
 913                }
 914                /* clear associative cache */
 915                for (i = 0; i < AFFS_AC_SIZE; i++)
 916                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 917                                AFFS_I(inode)->i_ac[i].ext = 0;
 918        }
 919        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 920
 921        blkcnt = AFFS_I(inode)->i_blkcnt;
 922        i = 0;
 923        blk = last_blk;
 924        if (inode->i_size) {
 925                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 926                blk++;
 927        } else
 928                AFFS_HEAD(ext_bh)->first_data = 0;
 929        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 930        size = AFFS_SB(sb)->s_hashsize;
 931        if (size > blkcnt - blk + i)
 932                size = blkcnt - blk + i;
 933        for (; i < size; i++, blk++) {
 934                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 935                AFFS_BLOCK(sb, ext_bh, i) = 0;
 936        }
 937        AFFS_TAIL(sb, ext_bh)->extension = 0;
 938        affs_fix_checksum(sb, ext_bh);
 939        mark_buffer_dirty_inode(ext_bh, inode);
 940        affs_brelse(ext_bh);
 941
 942        if (inode->i_size) {
 943                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 944                AFFS_I(inode)->i_extcnt = ext + 1;
 945                if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 946                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 947                        u32 tmp;
 948                        if (IS_ERR(bh)) {
 949                                affs_warning(sb, "truncate",
 950                                             "unexpected read error for last block %u (%ld)",
 951                                             ext, PTR_ERR(bh));
 952                                return;
 953                        }
 954                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 955                        AFFS_DATA_HEAD(bh)->next = 0;
 956                        affs_adjust_checksum(bh, -tmp);
 957                        affs_brelse(bh);
 958                }
 959        } else {
 960                AFFS_I(inode)->i_blkcnt = 0;
 961                AFFS_I(inode)->i_extcnt = 1;
 962        }
 963        AFFS_I(inode)->mmu_private = inode->i_size;
 964        // unlock cache
 965
 966        while (ext_key) {
 967                ext_bh = affs_bread(sb, ext_key);
 968                size = AFFS_SB(sb)->s_hashsize;
 969                if (size > blkcnt - blk)
 970                        size = blkcnt - blk;
 971                for (i = 0; i < size; i++, blk++)
 972                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 973                affs_free_block(sb, ext_key);
 974                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 975                affs_brelse(ext_bh);
 976        }
 977        affs_free_prealloc(inode);
 978}
 979
 980int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 981{
 982        struct inode *inode = filp->f_mapping->host;
 983        int ret, err;
 984
 985        err = file_write_and_wait_range(filp, start, end);
 986        if (err)
 987                return err;
 988
 989        inode_lock(inode);
 990        ret = write_inode_now(inode, 0);
 991        err = sync_blockdev(inode->i_sb->s_bdev);
 992        if (!ret)
 993                ret = err;
 994        inode_unlock(inode);
 995        return ret;
 996}
 997const struct file_operations affs_file_operations = {
 998        .llseek         = generic_file_llseek,
 999        .read_iter      = generic_file_read_iter,
1000        .write_iter     = generic_file_write_iter,
1001        .mmap           = generic_file_mmap,
1002        .open           = affs_file_open,
1003        .release        = affs_file_release,
1004        .fsync          = affs_file_fsync,
1005        .splice_read    = generic_file_splice_read,
1006};
1007
1008const struct inode_operations affs_file_inode_operations = {
1009        .setattr        = affs_notify_change,
1010};
1011