fs/affs/file.c

   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 <linux/mpage.h>
  19 #include "affs.h"
  20
  21 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
  22
  23 static int
  24 affs_file_open(struct inode *inode, struct file *filp)
  25 {
  26         pr_debug("open(%lu,%d)\n",
  27                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  28         atomic_inc(&AFFS_I(inode)->i_opencnt);
  29         return 0;
  30 }
  31
  32 static int
  33 affs_file_release(struct inode *inode, struct file *filp)
  34 {
  35         pr_debug("release(%lu, %d)\n",
  36                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
  37
  38         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
  39                 inode_lock(inode);
  40                 if (inode->i_size != AFFS_I(inode)->mmu_private)
  41                         affs_truncate(inode);
  42                 affs_free_prealloc(inode);
  43                 inode_unlock(inode);
  44         }
  45
  46         return 0;
  47 }
  48
  49 static int
  50 affs_grow_extcache(struct inode *inode, u32 lc_idx)
  51 {
  52         struct super_block      *sb = inode->i_sb;
  53         struct buffer_head      *bh;
  54         u32 lc_max;
  55         int i, j, key;
  56
  57         if (!AFFS_I(inode)->i_lc) {
  58                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
  59                 if (!ptr)
  60                         return -ENOMEM;
  61                 AFFS_I(inode)->i_lc = (u32 *)ptr;
  62                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
  63         }
  64
  65         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
  66
  67         if (AFFS_I(inode)->i_extcnt > lc_max) {
  68                 u32 lc_shift, lc_mask, tmp, off;
  69
  70                 /* need to recalculate linear cache, start from old size */
  71                 lc_shift = AFFS_I(inode)->i_lc_shift;
  72                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
  73                 for (; tmp; tmp >>= 1)
  74                         lc_shift++;
  75                 lc_mask = (1 << lc_shift) - 1;
  76
  77                 /* fix idx and old size to new shift */
  78                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  79                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
  80
  81                 /* first shrink old cache to make more space */
  82                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
  83                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
  84                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
  85
  86                 AFFS_I(inode)->i_lc_shift = lc_shift;
  87                 AFFS_I(inode)->i_lc_mask = lc_mask;
  88         }
  89
  90         /* fill cache to the needed index */
  91         i = AFFS_I(inode)->i_lc_size;
  92         AFFS_I(inode)->i_lc_size = lc_idx + 1;
  93         for (; i <= lc_idx; i++) {
  94                 if (!i) {
  95                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
  96                         continue;
  97                 }
  98                 key = AFFS_I(inode)->i_lc[i - 1];
  99                 j = AFFS_I(inode)->i_lc_mask + 1;
 100                 // unlock cache
 101                 for (; j > 0; j--) {
 102                         bh = affs_bread(sb, key);
 103                         if (!bh)
 104                                 goto err;
 105                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 106                         affs_brelse(bh);
 107                 }
 108                 // lock cache
 109                 AFFS_I(inode)->i_lc[i] = key;
 110         }
 111
 112         return 0;
 113
 114 err:
 115         // lock cache
 116         return -EIO;
 117 }
 118
 119 static struct buffer_head *
 120 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
 121 {
 122         struct super_block *sb = inode->i_sb;
 123         struct buffer_head *new_bh;
 124         u32 blocknr, tmp;
 125
 126         blocknr = affs_alloc_block(inode, bh->b_blocknr);
 127         if (!blocknr)
 128                 return ERR_PTR(-ENOSPC);
 129
 130         new_bh = affs_getzeroblk(sb, blocknr);
 131         if (!new_bh) {
 132                 affs_free_block(sb, blocknr);
 133                 return ERR_PTR(-EIO);
 134         }
 135
 136         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
 137         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
 138         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
 139         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
 140         affs_fix_checksum(sb, new_bh);
 141
 142         mark_buffer_dirty_inode(new_bh, inode);
 143
 144         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 145         if (tmp)
 146                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
 147         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
 148         affs_adjust_checksum(bh, blocknr - tmp);
 149         mark_buffer_dirty_inode(bh, inode);
 150
 151         AFFS_I(inode)->i_extcnt++;
 152         mark_inode_dirty(inode);
 153
 154         return new_bh;
 155 }
 156
 157 static inline struct buffer_head *
 158 affs_get_extblock(struct inode *inode, u32 ext)
 159 {
 160         /* inline the simplest case: same extended block as last time */
 161         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
 162         if (ext == AFFS_I(inode)->i_ext_last)
 163                 get_bh(bh);
 164         else
 165                 /* we have to do more (not inlined) */
 166                 bh = affs_get_extblock_slow(inode, ext);
 167
 168         return bh;
 169 }
 170
 171 static struct buffer_head *
 172 affs_get_extblock_slow(struct inode *inode, u32 ext)
 173 {
 174         struct super_block *sb = inode->i_sb;
 175         struct buffer_head *bh;
 176         u32 ext_key;
 177         u32 lc_idx, lc_off, ac_idx;
 178         u32 tmp, idx;
 179
 180         if (ext == AFFS_I(inode)->i_ext_last + 1) {
 181                 /* read the next extended block from the current one */
 182                 bh = AFFS_I(inode)->i_ext_bh;
 183                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 184                 if (ext < AFFS_I(inode)->i_extcnt)
 185                         goto read_ext;
 186                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 187                 bh = affs_alloc_extblock(inode, bh, ext);
 188                 if (IS_ERR(bh))
 189                         return bh;
 190                 goto store_ext;
 191         }
 192
 193         if (ext == 0) {
 194                 /* we seek back to the file header block */
 195                 ext_key = inode->i_ino;
 196                 goto read_ext;
 197         }
 198
 199         if (ext >= AFFS_I(inode)->i_extcnt) {
 200                 struct buffer_head *prev_bh;
 201
 202                 /* allocate a new extended block */
 203                 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
 204
 205                 /* get previous extended block */
 206                 prev_bh = affs_get_extblock(inode, ext - 1);
 207                 if (IS_ERR(prev_bh))
 208                         return prev_bh;
 209                 bh = affs_alloc_extblock(inode, prev_bh, ext);
 210                 affs_brelse(prev_bh);
 211                 if (IS_ERR(bh))
 212                         return bh;
 213                 goto store_ext;
 214         }
 215
 216 again:
 217         /* check if there is an extended cache and whether it's large enough */
 218         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
 219         lc_off = ext & AFFS_I(inode)->i_lc_mask;
 220
 221         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
 222                 int err;
 223
 224                 err = affs_grow_extcache(inode, lc_idx);
 225                 if (err)
 226                         return ERR_PTR(err);
 227                 goto again;
 228         }
 229
 230         /* every n'th key we find in the linear cache */
 231         if (!lc_off) {
 232                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
 233                 goto read_ext;
 234         }
 235
 236         /* maybe it's still in the associative cache */
 237         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
 238         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
 239                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
 240                 goto read_ext;
 241         }
 242
 243         /* try to find one of the previous extended blocks */
 244         tmp = ext;
 245         idx = ac_idx;
 246         while (--tmp, --lc_off > 0) {
 247                 idx = (idx - 1) & AFFS_AC_MASK;
 248                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
 249                         ext_key = AFFS_I(inode)->i_ac[idx].key;
 250                         goto find_ext;
 251                 }
 252         }
 253
 254         /* fall back to the linear cache */
 255         ext_key = AFFS_I(inode)->i_lc[lc_idx];
 256 find_ext:
 257         /* read all extended blocks until we find the one we need */
 258         //unlock cache
 259         do {
 260                 bh = affs_bread(sb, ext_key);
 261                 if (!bh)
 262                         goto err_bread;
 263                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
 264                 affs_brelse(bh);
 265                 tmp++;
 266         } while (tmp < ext);
 267         //lock cache
 268
 269         /* store it in the associative cache */
 270         // recalculate ac_idx?
 271         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
 272         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
 273
 274 read_ext:
 275         /* finally read the right extended block */
 276         //unlock cache
 277         bh = affs_bread(sb, ext_key);
 278         if (!bh)
 279                 goto err_bread;
 280         //lock cache
 281
 282 store_ext:
 283         /* release old cached extended block and store the new one */
 284         affs_brelse(AFFS_I(inode)->i_ext_bh);
 285         AFFS_I(inode)->i_ext_last = ext;
 286         AFFS_I(inode)->i_ext_bh = bh;
 287         get_bh(bh);
 288
 289         return bh;
 290
 291 err_bread:
 292         affs_brelse(bh);
 293         return ERR_PTR(-EIO);
 294 }
 295
 296 static int
 297 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
 298 {
 299         struct super_block      *sb = inode->i_sb;
 300         struct buffer_head      *ext_bh;
 301         u32                      ext;
 302
 303         pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
 304                  (unsigned long long)block);
 305
 306         BUG_ON(block > (sector_t)0x7fffffffUL);
 307
 308         if (block >= AFFS_I(inode)->i_blkcnt) {
 309                 if (block > AFFS_I(inode)->i_blkcnt || !create)
 310                         goto err_big;
 311         } else
 312                 create = 0;
 313
 314         //lock cache
 315         affs_lock_ext(inode);
 316
 317         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
 318         block -= ext * AFFS_SB(sb)->s_hashsize;
 319         ext_bh = affs_get_extblock(inode, ext);
 320         if (IS_ERR(ext_bh))
 321                 goto err_ext;
 322         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
 323
 324         if (create) {
 325                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
 326                 if (!blocknr)
 327                         goto err_alloc;
 328                 set_buffer_new(bh_result);
 329                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
 330                 AFFS_I(inode)->i_blkcnt++;
 331
 332                 /* store new block */
 333                 if (bh_result->b_blocknr)
 334                         affs_warning(sb, "get_block",
 335                                      "block already set (%llx)",
 336                                      (unsigned long long)bh_result->b_blocknr);
 337                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
 338                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
 339                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
 340                 bh_result->b_blocknr = blocknr;
 341
 342                 if (!block) {
 343                         /* insert first block into header block */
 344                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
 345                         if (tmp)
 346                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
 347                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
 348                         affs_adjust_checksum(ext_bh, blocknr - tmp);
 349                 }
 350         }
 351
 352         affs_brelse(ext_bh);
 353         //unlock cache
 354         affs_unlock_ext(inode);
 355         return 0;
 356
 357 err_big:
 358         affs_error(inode->i_sb, "get_block", "strange block request %llu",
 359                    (unsigned long long)block);
 360         return -EIO;
 361 err_ext:
 362         // unlock cache
 363         affs_unlock_ext(inode);
 364         return PTR_ERR(ext_bh);
 365 err_alloc:
 366         brelse(ext_bh);
 367         clear_buffer_mapped(bh_result);
 368         bh_result->b_bdev = NULL;
 369         // unlock cache
 370         affs_unlock_ext(inode);
 371         return -ENOSPC;
 372 }
 373
 374 static int affs_writepages(struct address_space *mapping,
 375                            struct writeback_control *wbc)
 376 {
 377         return mpage_writepages(mapping, wbc, affs_get_block);
 378 }
 379
 380 static int affs_read_folio(struct file *file, struct folio *folio)
 381 {
 382         return block_read_full_folio(folio, affs_get_block);
 383 }
 384
 385 static void affs_write_failed(struct address_space *mapping, loff_t to)
 386 {
 387         struct inode *inode = mapping->host;
 388
 389         if (to > inode->i_size) {
 390                 truncate_pagecache(inode, inode->i_size);
 391                 affs_truncate(inode);
 392         }
 393 }
 394
 395 static ssize_t
 396 affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 397 {
 398         struct file *file = iocb->ki_filp;
 399         struct address_space *mapping = file->f_mapping;
 400         struct inode *inode = mapping->host;
 401         size_t count = iov_iter_count(iter);
 402         loff_t offset = iocb->ki_pos;
 403         ssize_t ret;
 404
 405         if (iov_iter_rw(iter) == WRITE) {
 406                 loff_t size = offset + count;
 407
 408                 if (AFFS_I(inode)->mmu_private < size)
 409                         return 0;
 410         }
 411
 412         ret = blockdev_direct_IO(iocb, inode, iter, affs_get_block);
 413         if (ret < 0 && iov_iter_rw(iter) == WRITE)
 414                 affs_write_failed(mapping, offset + count);
 415         return ret;
 416 }
 417
 418 static int affs_write_begin(struct file *file, struct address_space *mapping,
 419                         loff_t pos, unsigned len,
 420                         struct page **pagep, void **fsdata)
 421 {
 422         int ret;
 423
 424         *pagep = NULL;
 425         ret = cont_write_begin(file, mapping, pos, len, pagep, fsdata,
 426                                 affs_get_block,
 427                                 &AFFS_I(mapping->host)->mmu_private);
 428         if (unlikely(ret))
 429                 affs_write_failed(mapping, pos + len);
 430
 431         return ret;
 432 }
 433
 434 static int affs_write_end(struct file *file, struct address_space *mapping,
 435                           loff_t pos, unsigned int len, unsigned int copied,
 436                           struct page *page, void *fsdata)
 437 {
 438         struct inode *inode = mapping->host;
 439         int ret;
 440
 441         ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 442
 443         /* Clear Archived bit on file writes, as AmigaOS would do */
 444         if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 445                 AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 446                 mark_inode_dirty(inode);
 447         }
 448
 449         return ret;
 450 }
 451
 452 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
 453 {
 454         return generic_block_bmap(mapping,block,affs_get_block);
 455 }
 456
 457 const struct address_space_operations affs_aops = {
 458         .dirty_folio    = block_dirty_folio,
 459         .invalidate_folio = block_invalidate_folio,
 460         .read_folio = affs_read_folio,
 461         .writepages = affs_writepages,
 462         .write_begin = affs_write_begin,
 463         .write_end = affs_write_end,
 464         .direct_IO = affs_direct_IO,
 465         .migrate_folio = buffer_migrate_folio,
 466         .bmap = _affs_bmap
 467 };
 468
 469 static inline struct buffer_head *
 470 affs_bread_ino(struct inode *inode, int block, int create)
 471 {
 472         struct buffer_head *bh, tmp_bh;
 473         int err;
 474
 475         tmp_bh.b_state = 0;
 476         err = affs_get_block(inode, block, &tmp_bh, create);
 477         if (!err) {
 478                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
 479                 if (bh) {
 480                         bh->b_state |= tmp_bh.b_state;
 481                         return bh;
 482                 }
 483                 err = -EIO;
 484         }
 485         return ERR_PTR(err);
 486 }
 487
 488 static inline struct buffer_head *
 489 affs_getzeroblk_ino(struct inode *inode, int block)
 490 {
 491         struct buffer_head *bh, tmp_bh;
 492         int err;
 493
 494         tmp_bh.b_state = 0;
 495         err = affs_get_block(inode, block, &tmp_bh, 1);
 496         if (!err) {
 497                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
 498                 if (bh) {
 499                         bh->b_state |= tmp_bh.b_state;
 500                         return bh;
 501                 }
 502                 err = -EIO;
 503         }
 504         return ERR_PTR(err);
 505 }
 506
 507 static inline struct buffer_head *
 508 affs_getemptyblk_ino(struct inode *inode, int block)
 509 {
 510         struct buffer_head *bh, tmp_bh;
 511         int err;
 512
 513         tmp_bh.b_state = 0;
 514         err = affs_get_block(inode, block, &tmp_bh, 1);
 515         if (!err) {
 516                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
 517                 if (bh) {
 518                         bh->b_state |= tmp_bh.b_state;
 519                         return bh;
 520                 }
 521                 err = -EIO;
 522         }
 523         return ERR_PTR(err);
 524 }
 525
 526 static int affs_do_read_folio_ofs(struct folio *folio, size_t to, int create)
 527 {
 528         struct inode *inode = folio->mapping->host;
 529         struct super_block *sb = inode->i_sb;
 530         struct buffer_head *bh;
 531         size_t pos = 0;
 532         size_t bidx, boff, bsize;
 533         u32 tmp;
 534
 535         pr_debug("%s(%lu, %ld, 0, %zu)\n", __func__, inode->i_ino,
 536                  folio->index, to);
 537         BUG_ON(to > folio_size(folio));
 538         bsize = AFFS_SB(sb)->s_data_blksize;
 539         tmp = folio_pos(folio);
 540         bidx = tmp / bsize;
 541         boff = tmp % bsize;
 542
 543         while (pos < to) {
 544                 bh = affs_bread_ino(inode, bidx, create);
 545                 if (IS_ERR(bh))
 546                         return PTR_ERR(bh);
 547                 tmp = min(bsize - boff, to - pos);
 548                 BUG_ON(pos + tmp > to || tmp > bsize);
 549                 memcpy_to_folio(folio, pos, AFFS_DATA(bh) + boff, tmp);
 550                 affs_brelse(bh);
 551                 bidx++;
 552                 pos += tmp;
 553                 boff = 0;
 554         }
 555         return 0;
 556 }
 557
 558 static int
 559 affs_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
 624 out:
 625         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 626         return PTR_ERR(bh);
 627 }
 628
 629 static int affs_read_folio_ofs(struct file *file, struct folio *folio)
 630 {
 631         struct inode *inode = folio->mapping->host;
 632         size_t to;
 633         int err;
 634
 635         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, folio->index);
 636         to = folio_size(folio);
 637         if (folio_pos(folio) + to > inode->i_size) {
 638                 to = inode->i_size - folio_pos(folio);
 639                 folio_zero_segment(folio, to, folio_size(folio));
 640         }
 641
 642         err = affs_do_read_folio_ofs(folio, to, 0);
 643         if (!err)
 644                 folio_mark_uptodate(folio);
 645         folio_unlock(folio);
 646         return err;
 647 }
 648
 649 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 650                                 loff_t pos, unsigned len,
 651                                 struct page **pagep, void **fsdata)
 652 {
 653         struct inode *inode = mapping->host;
 654         struct folio *folio;
 655         pgoff_t index;
 656         int err = 0;
 657
 658         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 659                  pos + len);
 660         if (pos > AFFS_I(inode)->mmu_private) {
 661                 /* XXX: this probably leaves a too-big i_size in case of
 662                  * failure. Should really be updating i_size at write_end time
 663                  */
 664                 err = affs_extent_file_ofs(inode, pos);
 665                 if (err)
 666                         return err;
 667         }
 668
 669         index = pos >> PAGE_SHIFT;
 670         folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
 671                         mapping_gfp_mask(mapping));
 672         if (IS_ERR(folio))
 673                 return PTR_ERR(folio);
 674         *pagep = &folio->page;
 675
 676         if (folio_test_uptodate(folio))
 677                 return 0;
 678
 679         /* XXX: inefficient but safe in the face of short writes */
 680         err = affs_do_read_folio_ofs(folio, folio_size(folio), 1);
 681         if (err) {
 682                 folio_unlock(folio);
 683                 folio_put(folio);
 684         }
 685         return err;
 686 }
 687
 688 static 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 folio *folio = page_folio(page);
 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 folio 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 = folio_address(folio);
 714
 715         bh = NULL;
 716         written = 0;
 717         tmp = (folio->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         folio_mark_uptodate(folio);
 810
 811 done:
 812         affs_brelse(bh);
 813         tmp = (folio->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
 823 err_first_bh:
 824         folio_unlock(folio);
 825         folio_put(folio);
 826
 827         return written;
 828
 829 err_bh:
 830         bh = prev_bh;
 831         if (!written)
 832                 written = PTR_ERR(bh);
 833         goto done;
 834 }
 835
 836 const struct address_space_operations affs_aops_ofs = {
 837         .dirty_folio    = block_dirty_folio,
 838         .invalidate_folio = block_invalidate_folio,
 839         .read_folio = affs_read_folio_ofs,
 840         //.writepages = affs_writepages_ofs,
 841         .write_begin = affs_write_begin_ofs,
 842         .write_end = affs_write_end_ofs,
 843         .migrate_folio = filemap_migrate_folio,
 844 };
 845
 846 /* Free any preallocated blocks. */
 847
 848 void
 849 affs_free_prealloc(struct inode *inode)
 850 {
 851         struct super_block *sb = inode->i_sb;
 852
 853         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 854
 855         while (AFFS_I(inode)->i_pa_cnt) {
 856                 AFFS_I(inode)->i_pa_cnt--;
 857                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 858         }
 859 }
 860
 861 /* Truncate (or enlarge) a file to the requested size. */
 862
 863 void
 864 affs_truncate(struct inode *inode)
 865 {
 866         struct super_block *sb = inode->i_sb;
 867         u32 ext, ext_key;
 868         u32 last_blk, blkcnt, blk;
 869         u32 size;
 870         struct buffer_head *ext_bh;
 871         int i;
 872
 873         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 874                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 875
 876         last_blk = 0;
 877         ext = 0;
 878         if (inode->i_size) {
 879                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 880                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 881         }
 882
 883         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 884                 struct address_space *mapping = inode->i_mapping;
 885                 struct page *page;
 886                 void *fsdata = NULL;
 887                 loff_t isize = inode->i_size;
 888                 int res;
 889
 890                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, &page, &fsdata);
 891                 if (!res)
 892                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 893                 else
 894                         inode->i_size = AFFS_I(inode)->mmu_private;
 895                 mark_inode_dirty(inode);
 896                 return;
 897         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 898                 return;
 899
 900         // lock cache
 901         ext_bh = affs_get_extblock(inode, ext);
 902         if (IS_ERR(ext_bh)) {
 903                 affs_warning(sb, "truncate",
 904                              "unexpected read error for ext block %u (%ld)",
 905                              ext, PTR_ERR(ext_bh));
 906                 return;
 907         }
 908         if (AFFS_I(inode)->i_lc) {
 909                 /* clear linear cache */
 910                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 911                 if (AFFS_I(inode)->i_lc_size > i) {
 912                         AFFS_I(inode)->i_lc_size = i;
 913                         for (; i < AFFS_LC_SIZE; i++)
 914                                 AFFS_I(inode)->i_lc[i] = 0;
 915                 }
 916                 /* clear associative cache */
 917                 for (i = 0; i < AFFS_AC_SIZE; i++)
 918                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 919                                 AFFS_I(inode)->i_ac[i].ext = 0;
 920         }
 921         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 922
 923         blkcnt = AFFS_I(inode)->i_blkcnt;
 924         i = 0;
 925         blk = last_blk;
 926         if (inode->i_size) {
 927                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 928                 blk++;
 929         } else
 930                 AFFS_HEAD(ext_bh)->first_data = 0;
 931         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 932         size = AFFS_SB(sb)->s_hashsize;
 933         if (size > blkcnt - blk + i)
 934                 size = blkcnt - blk + i;
 935         for (; i < size; i++, blk++) {
 936                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 937                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 938         }
 939         AFFS_TAIL(sb, ext_bh)->extension = 0;
 940         affs_fix_checksum(sb, ext_bh);
 941         mark_buffer_dirty_inode(ext_bh, inode);
 942         affs_brelse(ext_bh);
 943
 944         if (inode->i_size) {
 945                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 946                 AFFS_I(inode)->i_extcnt = ext + 1;
 947                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 948                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 949                         u32 tmp;
 950                         if (IS_ERR(bh)) {
 951                                 affs_warning(sb, "truncate",
 952                                              "unexpected read error for last block %u (%ld)",
 953                                              ext, PTR_ERR(bh));
 954                                 return;
 955                         }
 956                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 957                         AFFS_DATA_HEAD(bh)->next = 0;
 958                         affs_adjust_checksum(bh, -tmp);
 959                         affs_brelse(bh);
 960                 }
 961         } else {
 962                 AFFS_I(inode)->i_blkcnt = 0;
 963                 AFFS_I(inode)->i_extcnt = 1;
 964         }
 965         AFFS_I(inode)->mmu_private = inode->i_size;
 966         // unlock cache
 967
 968         while (ext_key) {
 969                 ext_bh = affs_bread(sb, ext_key);
 970                 size = AFFS_SB(sb)->s_hashsize;
 971                 if (size > blkcnt - blk)
 972                         size = blkcnt - blk;
 973                 for (i = 0; i < size; i++, blk++)
 974                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 975                 affs_free_block(sb, ext_key);
 976                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 977                 affs_brelse(ext_bh);
 978         }
 979         affs_free_prealloc(inode);
 980 }
 981
 982 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 983 {
 984         struct inode *inode = filp->f_mapping->host;
 985         int ret, err;
 986
 987         err = file_write_and_wait_range(filp, start, end);
 988         if (err)
 989                 return err;
 990
 991         inode_lock(inode);
 992         ret = write_inode_now(inode, 0);
 993         err = sync_blockdev(inode->i_sb->s_bdev);
 994         if (!ret)
 995                 ret = err;
 996         inode_unlock(inode);
 997         return ret;
 998 }
 999 const struct file_operations affs_file_operations = {
1000         .llseek         = generic_file_llseek,
1001         .read_iter      = generic_file_read_iter,
1002         .write_iter     = generic_file_write_iter,
1003         .mmap           = generic_file_mmap,
1004         .open           = affs_file_open,
1005         .release        = affs_file_release,
1006         .fsync          = affs_file_fsync,
1007         .splice_read    = filemap_splice_read,
1008 };
1009
1010 const struct inode_operations affs_file_inode_operations = {
1011         .setattr        = affs_notify_change,
1012 };