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        .readpage = affs_readpage,
 457        .writepage = affs_writepage,
 458        .write_begin = affs_write_begin,
 459        .write_end = affs_write_end,
 460        .direct_IO = affs_direct_IO,
 461        .bmap = _affs_bmap
 462};
 463
 464static inline struct buffer_head *
 465affs_bread_ino(struct inode *inode, int block, int create)
 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, create);
 472        if (!err) {
 473                bh = affs_bread(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_getzeroblk_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_getzeroblk(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 inline struct buffer_head *
 503affs_getemptyblk_ino(struct inode *inode, int block)
 504{
 505        struct buffer_head *bh, tmp_bh;
 506        int err;
 507
 508        tmp_bh.b_state = 0;
 509        err = affs_get_block(inode, block, &tmp_bh, 1);
 510        if (!err) {
 511                bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 512                if (bh) {
 513                        bh->b_state |= tmp_bh.b_state;
 514                        return bh;
 515                }
 516                err = -EIO;
 517        }
 518        return ERR_PTR(err);
 519}
 520
 521static int
 522affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 523{
 524        struct inode *inode = page->mapping->host;
 525        struct super_block *sb = inode->i_sb;
 526        struct buffer_head *bh;
 527        char *data;
 528        unsigned pos = 0;
 529        u32 bidx, boff, bsize;
 530        u32 tmp;
 531
 532        pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 533                 page->index, to);
 534        BUG_ON(to > PAGE_SIZE);
 535        bsize = AFFS_SB(sb)->s_data_blksize;
 536        tmp = page->index << PAGE_SHIFT;
 537        bidx = tmp / bsize;
 538        boff = tmp % bsize;
 539
 540        while (pos < to) {
 541                bh = affs_bread_ino(inode, bidx, create);
 542                if (IS_ERR(bh))
 543                        return PTR_ERR(bh);
 544                tmp = min(bsize - boff, to - pos);
 545                BUG_ON(pos + tmp > to || tmp > bsize);
 546                data = kmap_atomic(page);
 547                memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
 548                kunmap_atomic(data);
 549                affs_brelse(bh);
 550                bidx++;
 551                pos += tmp;
 552                boff = 0;
 553        }
 554        flush_dcache_page(page);
 555        return 0;
 556}
 557
 558static int
 559affs_extent_file_ofs(struct inode *inode, u32 newsize)
 560{
 561        struct super_block *sb = inode->i_sb;
 562        struct buffer_head *bh, *prev_bh;
 563        u32 bidx, boff;
 564        u32 size, bsize;
 565        u32 tmp;
 566
 567        pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
 568        bsize = AFFS_SB(sb)->s_data_blksize;
 569        bh = NULL;
 570        size = AFFS_I(inode)->mmu_private;
 571        bidx = size / bsize;
 572        boff = size % bsize;
 573        if (boff) {
 574                bh = affs_bread_ino(inode, bidx, 0);
 575                if (IS_ERR(bh))
 576                        return PTR_ERR(bh);
 577                tmp = min(bsize - boff, newsize - size);
 578                BUG_ON(boff + tmp > bsize || tmp > bsize);
 579                memset(AFFS_DATA(bh) + boff, 0, tmp);
 580                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 581                affs_fix_checksum(sb, bh);
 582                mark_buffer_dirty_inode(bh, inode);
 583                size += tmp;
 584                bidx++;
 585        } else if (bidx) {
 586                bh = affs_bread_ino(inode, bidx - 1, 0);
 587                if (IS_ERR(bh))
 588                        return PTR_ERR(bh);
 589        }
 590
 591        while (size < newsize) {
 592                prev_bh = bh;
 593                bh = affs_getzeroblk_ino(inode, bidx);
 594                if (IS_ERR(bh))
 595                        goto out;
 596                tmp = min(bsize, newsize - size);
 597                BUG_ON(tmp > bsize);
 598                AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 599                AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 600                AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 601                AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 602                affs_fix_checksum(sb, bh);
 603                bh->b_state &= ~(1UL << BH_New);
 604                mark_buffer_dirty_inode(bh, inode);
 605                if (prev_bh) {
 606                        u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 607
 608                        if (tmp_next)
 609                                affs_warning(sb, "extent_file_ofs",
 610                                             "next block already set for %d (%d)",
 611                                             bidx, tmp_next);
 612                        AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 613                        affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 614                        mark_buffer_dirty_inode(prev_bh, inode);
 615                        affs_brelse(prev_bh);
 616                }
 617                size += bsize;
 618                bidx++;
 619        }
 620        affs_brelse(bh);
 621        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 622        return 0;
 623
 624out:
 625        inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 626        return PTR_ERR(bh);
 627}
 628
 629static int
 630affs_readpage_ofs(struct file *file, struct page *page)
 631{
 632        struct inode *inode = page->mapping->host;
 633        u32 to;
 634        int err;
 635
 636        pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 637        to = PAGE_SIZE;
 638        if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 639                to = inode->i_size & ~PAGE_MASK;
 640                memset(page_address(page) + to, 0, PAGE_SIZE - to);
 641        }
 642
 643        err = affs_do_readpage_ofs(page, to, 0);
 644        if (!err)
 645                SetPageUptodate(page);
 646        unlock_page(page);
 647        return err;
 648}
 649
 650static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 651                                loff_t pos, unsigned len, unsigned flags,
 652                                struct page **pagep, void **fsdata)
 653{
 654        struct inode *inode = mapping->host;
 655        struct page *page;
 656        pgoff_t index;
 657        int err = 0;
 658
 659        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 660                 pos + len);
 661        if (pos > AFFS_I(inode)->mmu_private) {
 662                /* XXX: this probably leaves a too-big i_size in case of
 663                 * failure. Should really be updating i_size at write_end time
 664                 */
 665                err = affs_extent_file_ofs(inode, pos);
 666                if (err)
 667                        return err;
 668        }
 669
 670        index = pos >> PAGE_SHIFT;
 671        page = grab_cache_page_write_begin(mapping, index, flags);
 672        if (!page)
 673                return -ENOMEM;
 674        *pagep = page;
 675
 676        if (PageUptodate(page))
 677                return 0;
 678
 679        /* XXX: inefficient but safe in the face of short writes */
 680        err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 681        if (err) {
 682                unlock_page(page);
 683                put_page(page);
 684        }
 685        return err;
 686}
 687
 688static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 689                                loff_t pos, unsigned len, unsigned copied,
 690                                struct page *page, void *fsdata)
 691{
 692        struct inode *inode = mapping->host;
 693        struct super_block *sb = inode->i_sb;
 694        struct buffer_head *bh, *prev_bh;
 695        char *data;
 696        u32 bidx, boff, bsize;
 697        unsigned from, to;
 698        u32 tmp;
 699        int written;
 700
 701        from = pos & (PAGE_SIZE - 1);
 702        to = from + len;
 703        /*
 704         * XXX: not sure if this can handle short copies (len < copied), but
 705         * we don't have to, because the page should always be uptodate here,
 706         * due to write_begin.
 707         */
 708
 709        pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 710                 pos + len);
 711        bsize = AFFS_SB(sb)->s_data_blksize;
 712        data = page_address(page);
 713
 714        bh = NULL;
 715        written = 0;
 716        tmp = (page->index << PAGE_SHIFT) + from;
 717        bidx = tmp / bsize;
 718        boff = tmp % bsize;
 719        if (boff) {
 720                bh = affs_bread_ino(inode, bidx, 0);
 721                if (IS_ERR(bh)) {
 722                        written = PTR_ERR(bh);
 723                        goto err_first_bh;
 724                }
 725                tmp = min(bsize - boff, to - from);
 726                BUG_ON(boff + tmp > bsize || tmp > bsize);
 727                memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 728                be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 729                affs_fix_checksum(sb, bh);
 730                mark_buffer_dirty_inode(bh, inode);
 731                written += tmp;
 732                from += tmp;
 733                bidx++;
 734        } else if (bidx) {
 735                bh = affs_bread_ino(inode, bidx - 1, 0);
 736                if (IS_ERR(bh)) {
 737                        written = PTR_ERR(bh);
 738                        goto err_first_bh;
 739                }
 740        }
 741        while (from + bsize <= to) {
 742                prev_bh = bh;
 743                bh = affs_getemptyblk_ino(inode, bidx);
 744                if (IS_ERR(bh))
 745                        goto err_bh;
 746                memcpy(AFFS_DATA(bh), data + from, bsize);
 747                if (buffer_new(bh)) {
 748                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 749                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 750                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 751                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 752                        AFFS_DATA_HEAD(bh)->next = 0;
 753                        bh->b_state &= ~(1UL << BH_New);
 754                        if (prev_bh) {
 755                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 756
 757                                if (tmp_next)
 758                                        affs_warning(sb, "commit_write_ofs",
 759                                                     "next block already set for %d (%d)",
 760                                                     bidx, tmp_next);
 761                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 762                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 763                                mark_buffer_dirty_inode(prev_bh, inode);
 764                        }
 765                }
 766                affs_brelse(prev_bh);
 767                affs_fix_checksum(sb, bh);
 768                mark_buffer_dirty_inode(bh, inode);
 769                written += bsize;
 770                from += bsize;
 771                bidx++;
 772        }
 773        if (from < to) {
 774                prev_bh = bh;
 775                bh = affs_bread_ino(inode, bidx, 1);
 776                if (IS_ERR(bh))
 777                        goto err_bh;
 778                tmp = min(bsize, to - from);
 779                BUG_ON(tmp > bsize);
 780                memcpy(AFFS_DATA(bh), data + from, tmp);
 781                if (buffer_new(bh)) {
 782                        AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 783                        AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 784                        AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 785                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 786                        AFFS_DATA_HEAD(bh)->next = 0;
 787                        bh->b_state &= ~(1UL << BH_New);
 788                        if (prev_bh) {
 789                                u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 790
 791                                if (tmp_next)
 792                                        affs_warning(sb, "commit_write_ofs",
 793                                                     "next block already set for %d (%d)",
 794                                                     bidx, tmp_next);
 795                                AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 796                                affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 797                                mark_buffer_dirty_inode(prev_bh, inode);
 798                        }
 799                } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 800                        AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 801                affs_brelse(prev_bh);
 802                affs_fix_checksum(sb, bh);
 803                mark_buffer_dirty_inode(bh, inode);
 804                written += tmp;
 805                from += tmp;
 806                bidx++;
 807        }
 808        SetPageUptodate(page);
 809
 810done:
 811        affs_brelse(bh);
 812        tmp = (page->index << PAGE_SHIFT) + from;
 813        if (tmp > inode->i_size)
 814                inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 815
 816        /* Clear Archived bit on file writes, as AmigaOS would do */
 817        if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 818                AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 819                mark_inode_dirty(inode);
 820        }
 821
 822err_first_bh:
 823        unlock_page(page);
 824        put_page(page);
 825
 826        return written;
 827
 828err_bh:
 829        bh = prev_bh;
 830        if (!written)
 831                written = PTR_ERR(bh);
 832        goto done;
 833}
 834
 835const struct address_space_operations affs_aops_ofs = {
 836        .readpage = affs_readpage_ofs,
 837        //.writepage = affs_writepage_ofs,
 838        .write_begin = affs_write_begin_ofs,
 839        .write_end = affs_write_end_ofs
 840};
 841
 842/* Free any preallocated blocks. */
 843
 844void
 845affs_free_prealloc(struct inode *inode)
 846{
 847        struct super_block *sb = inode->i_sb;
 848
 849        pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 850
 851        while (AFFS_I(inode)->i_pa_cnt) {
 852                AFFS_I(inode)->i_pa_cnt--;
 853                affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 854        }
 855}
 856
 857/* Truncate (or enlarge) a file to the requested size. */
 858
 859void
 860affs_truncate(struct inode *inode)
 861{
 862        struct super_block *sb = inode->i_sb;
 863        u32 ext, ext_key;
 864        u32 last_blk, blkcnt, blk;
 865        u32 size;
 866        struct buffer_head *ext_bh;
 867        int i;
 868
 869        pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 870                 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 871
 872        last_blk = 0;
 873        ext = 0;
 874        if (inode->i_size) {
 875                last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 876                ext = last_blk / AFFS_SB(sb)->s_hashsize;
 877        }
 878
 879        if (inode->i_size > AFFS_I(inode)->mmu_private) {
 880                struct address_space *mapping = inode->i_mapping;
 881                struct page *page;
 882                void *fsdata;
 883                loff_t isize = inode->i_size;
 884                int res;
 885
 886                res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
 887                if (!res)
 888                        res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 889                else
 890                        inode->i_size = AFFS_I(inode)->mmu_private;
 891                mark_inode_dirty(inode);
 892                return;
 893        } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 894                return;
 895
 896        // lock cache
 897        ext_bh = affs_get_extblock(inode, ext);
 898        if (IS_ERR(ext_bh)) {
 899                affs_warning(sb, "truncate",
 900                             "unexpected read error for ext block %u (%ld)",
 901                             ext, PTR_ERR(ext_bh));
 902                return;
 903        }
 904        if (AFFS_I(inode)->i_lc) {
 905                /* clear linear cache */
 906                i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 907                if (AFFS_I(inode)->i_lc_size > i) {
 908                        AFFS_I(inode)->i_lc_size = i;
 909                        for (; i < AFFS_LC_SIZE; i++)
 910                                AFFS_I(inode)->i_lc[i] = 0;
 911                }
 912                /* clear associative cache */
 913                for (i = 0; i < AFFS_AC_SIZE; i++)
 914                        if (AFFS_I(inode)->i_ac[i].ext >= ext)
 915                                AFFS_I(inode)->i_ac[i].ext = 0;
 916        }
 917        ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 918
 919        blkcnt = AFFS_I(inode)->i_blkcnt;
 920        i = 0;
 921        blk = last_blk;
 922        if (inode->i_size) {
 923                i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 924                blk++;
 925        } else
 926                AFFS_HEAD(ext_bh)->first_data = 0;
 927        AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 928        size = AFFS_SB(sb)->s_hashsize;
 929        if (size > blkcnt - blk + i)
 930                size = blkcnt - blk + i;
 931        for (; i < size; i++, blk++) {
 932                affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 933                AFFS_BLOCK(sb, ext_bh, i) = 0;
 934        }
 935        AFFS_TAIL(sb, ext_bh)->extension = 0;
 936        affs_fix_checksum(sb, ext_bh);
 937        mark_buffer_dirty_inode(ext_bh, inode);
 938        affs_brelse(ext_bh);
 939
 940        if (inode->i_size) {
 941                AFFS_I(inode)->i_blkcnt = last_blk + 1;
 942                AFFS_I(inode)->i_extcnt = ext + 1;
 943                if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 944                        struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 945                        u32 tmp;
 946                        if (IS_ERR(bh)) {
 947                                affs_warning(sb, "truncate",
 948                                             "unexpected read error for last block %u (%ld)",
 949                                             ext, PTR_ERR(bh));
 950                                return;
 951                        }
 952                        tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 953                        AFFS_DATA_HEAD(bh)->next = 0;
 954                        affs_adjust_checksum(bh, -tmp);
 955                        affs_brelse(bh);
 956                }
 957        } else {
 958                AFFS_I(inode)->i_blkcnt = 0;
 959                AFFS_I(inode)->i_extcnt = 1;
 960        }
 961        AFFS_I(inode)->mmu_private = inode->i_size;
 962        // unlock cache
 963
 964        while (ext_key) {
 965                ext_bh = affs_bread(sb, ext_key);
 966                size = AFFS_SB(sb)->s_hashsize;
 967                if (size > blkcnt - blk)
 968                        size = blkcnt - blk;
 969                for (i = 0; i < size; i++, blk++)
 970                        affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 971                affs_free_block(sb, ext_key);
 972                ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 973                affs_brelse(ext_bh);
 974        }
 975        affs_free_prealloc(inode);
 976}
 977
 978int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 979{
 980        struct inode *inode = filp->f_mapping->host;
 981        int ret, err;
 982
 983        err = file_write_and_wait_range(filp, start, end);
 984        if (err)
 985                return err;
 986
 987        inode_lock(inode);
 988        ret = write_inode_now(inode, 0);
 989        err = sync_blockdev(inode->i_sb->s_bdev);
 990        if (!ret)
 991                ret = err;
 992        inode_unlock(inode);
 993        return ret;
 994}
 995const struct file_operations affs_file_operations = {
 996        .llseek         = generic_file_llseek,
 997        .read_iter      = generic_file_read_iter,
 998        .write_iter     = generic_file_write_iter,
 999        .mmap           = generic_file_mmap,
1000        .open           = affs_file_open,
1001        .release        = affs_file_release,
1002        .fsync          = affs_file_fsync,
1003        .splice_read    = generic_file_splice_read,
1004};
1005
1006const struct inode_operations affs_file_inode_operations = {
1007        .setattr        = affs_notify_change,
1008};
1009