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
 527 affs_do_readpage_ofs(struct page *page, unsigned to, int create)
 528 {
 529         struct inode *inode = page->mapping->host;
 530         struct super_block *sb = inode->i_sb;
 531         struct buffer_head *bh;
 532         unsigned pos = 0;
 533         u32 bidx, boff, bsize;
 534         u32 tmp;
 535
 536         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
 537                  page->index, to);
 538         BUG_ON(to > PAGE_SIZE);
 539         bsize = AFFS_SB(sb)->s_data_blksize;
 540         tmp = page->index << PAGE_SHIFT;
 541         bidx = tmp / bsize;
 542         boff = tmp % bsize;
 543
 544         while (pos < to) {
 545                 bh = affs_bread_ino(inode, bidx, create);
 546                 if (IS_ERR(bh))
 547                         return PTR_ERR(bh);
 548                 tmp = min(bsize - boff, to - pos);
 549                 BUG_ON(pos + tmp > to || tmp > bsize);
 550                 memcpy_to_page(page, pos, AFFS_DATA(bh) + boff, tmp);
 551                 affs_brelse(bh);
 552                 bidx++;
 553                 pos += tmp;
 554                 boff = 0;
 555         }
 556         return 0;
 557 }
 558
 559 static int
 560 affs_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
 625 out:
 626         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
 627         return PTR_ERR(bh);
 628 }
 629
 630 static int
 631 affs_read_folio_ofs(struct file *file, struct folio *folio)
 632 {
 633         struct page *page = &folio->page;
 634         struct inode *inode = page->mapping->host;
 635         u32 to;
 636         int err;
 637
 638         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
 639         to = PAGE_SIZE;
 640         if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
 641                 to = inode->i_size & ~PAGE_MASK;
 642                 memset(page_address(page) + to, 0, PAGE_SIZE - to);
 643         }
 644
 645         err = affs_do_readpage_ofs(page, to, 0);
 646         if (!err)
 647                 SetPageUptodate(page);
 648         unlock_page(page);
 649         return err;
 650 }
 651
 652 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
 653                                 loff_t pos, unsigned len,
 654                                 struct page **pagep, void **fsdata)
 655 {
 656         struct inode *inode = mapping->host;
 657         struct page *page;
 658         pgoff_t index;
 659         int err = 0;
 660
 661         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 662                  pos + len);
 663         if (pos > AFFS_I(inode)->mmu_private) {
 664                 /* XXX: this probably leaves a too-big i_size in case of
 665                  * failure. Should really be updating i_size at write_end time
 666                  */
 667                 err = affs_extent_file_ofs(inode, pos);
 668                 if (err)
 669                         return err;
 670         }
 671
 672         index = pos >> PAGE_SHIFT;
 673         page = grab_cache_page_write_begin(mapping, index);
 674         if (!page)
 675                 return -ENOMEM;
 676         *pagep = page;
 677
 678         if (PageUptodate(page))
 679                 return 0;
 680
 681         /* XXX: inefficient but safe in the face of short writes */
 682         err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
 683         if (err) {
 684                 unlock_page(page);
 685                 put_page(page);
 686         }
 687         return err;
 688 }
 689
 690 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
 691                                 loff_t pos, unsigned len, unsigned copied,
 692                                 struct page *page, void *fsdata)
 693 {
 694         struct inode *inode = mapping->host;
 695         struct super_block *sb = inode->i_sb;
 696         struct buffer_head *bh, *prev_bh;
 697         char *data;
 698         u32 bidx, boff, bsize;
 699         unsigned from, to;
 700         u32 tmp;
 701         int written;
 702
 703         from = pos & (PAGE_SIZE - 1);
 704         to = from + len;
 705         /*
 706          * XXX: not sure if this can handle short copies (len < copied), but
 707          * we don't have to, because the page should always be uptodate here,
 708          * due to write_begin.
 709          */
 710
 711         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
 712                  pos + len);
 713         bsize = AFFS_SB(sb)->s_data_blksize;
 714         data = page_address(page);
 715
 716         bh = NULL;
 717         written = 0;
 718         tmp = (page->index << PAGE_SHIFT) + from;
 719         bidx = tmp / bsize;
 720         boff = tmp % bsize;
 721         if (boff) {
 722                 bh = affs_bread_ino(inode, bidx, 0);
 723                 if (IS_ERR(bh)) {
 724                         written = PTR_ERR(bh);
 725                         goto err_first_bh;
 726                 }
 727                 tmp = min(bsize - boff, to - from);
 728                 BUG_ON(boff + tmp > bsize || tmp > bsize);
 729                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
 730                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
 731                 affs_fix_checksum(sb, bh);
 732                 mark_buffer_dirty_inode(bh, inode);
 733                 written += tmp;
 734                 from += tmp;
 735                 bidx++;
 736         } else if (bidx) {
 737                 bh = affs_bread_ino(inode, bidx - 1, 0);
 738                 if (IS_ERR(bh)) {
 739                         written = PTR_ERR(bh);
 740                         goto err_first_bh;
 741                 }
 742         }
 743         while (from + bsize <= to) {
 744                 prev_bh = bh;
 745                 bh = affs_getemptyblk_ino(inode, bidx);
 746                 if (IS_ERR(bh))
 747                         goto err_bh;
 748                 memcpy(AFFS_DATA(bh), data + from, bsize);
 749                 if (buffer_new(bh)) {
 750                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 751                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 752                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 753                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
 754                         AFFS_DATA_HEAD(bh)->next = 0;
 755                         bh->b_state &= ~(1UL << BH_New);
 756                         if (prev_bh) {
 757                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 758
 759                                 if (tmp_next)
 760                                         affs_warning(sb, "commit_write_ofs",
 761                                                      "next block already set for %d (%d)",
 762                                                      bidx, tmp_next);
 763                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 764                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 765                                 mark_buffer_dirty_inode(prev_bh, inode);
 766                         }
 767                 }
 768                 affs_brelse(prev_bh);
 769                 affs_fix_checksum(sb, bh);
 770                 mark_buffer_dirty_inode(bh, inode);
 771                 written += bsize;
 772                 from += bsize;
 773                 bidx++;
 774         }
 775         if (from < to) {
 776                 prev_bh = bh;
 777                 bh = affs_bread_ino(inode, bidx, 1);
 778                 if (IS_ERR(bh))
 779                         goto err_bh;
 780                 tmp = min(bsize, to - from);
 781                 BUG_ON(tmp > bsize);
 782                 memcpy(AFFS_DATA(bh), data + from, tmp);
 783                 if (buffer_new(bh)) {
 784                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
 785                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
 786                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
 787                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 788                         AFFS_DATA_HEAD(bh)->next = 0;
 789                         bh->b_state &= ~(1UL << BH_New);
 790                         if (prev_bh) {
 791                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
 792
 793                                 if (tmp_next)
 794                                         affs_warning(sb, "commit_write_ofs",
 795                                                      "next block already set for %d (%d)",
 796                                                      bidx, tmp_next);
 797                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
 798                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
 799                                 mark_buffer_dirty_inode(prev_bh, inode);
 800                         }
 801                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
 802                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
 803                 affs_brelse(prev_bh);
 804                 affs_fix_checksum(sb, bh);
 805                 mark_buffer_dirty_inode(bh, inode);
 806                 written += tmp;
 807                 from += tmp;
 808                 bidx++;
 809         }
 810         SetPageUptodate(page);
 811
 812 done:
 813         affs_brelse(bh);
 814         tmp = (page->index << PAGE_SHIFT) + from;
 815         if (tmp > inode->i_size)
 816                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
 817
 818         /* Clear Archived bit on file writes, as AmigaOS would do */
 819         if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
 820                 AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
 821                 mark_inode_dirty(inode);
 822         }
 823
 824 err_first_bh:
 825         unlock_page(page);
 826         put_page(page);
 827
 828         return written;
 829
 830 err_bh:
 831         bh = prev_bh;
 832         if (!written)
 833                 written = PTR_ERR(bh);
 834         goto done;
 835 }
 836
 837 const struct address_space_operations affs_aops_ofs = {
 838         .dirty_folio    = block_dirty_folio,
 839         .invalidate_folio = block_invalidate_folio,
 840         .read_folio = affs_read_folio_ofs,
 841         //.writepages = affs_writepages_ofs,
 842         .write_begin = affs_write_begin_ofs,
 843         .write_end = affs_write_end_ofs,
 844         .migrate_folio = filemap_migrate_folio,
 845 };
 846
 847 /* Free any preallocated blocks. */
 848
 849 void
 850 affs_free_prealloc(struct inode *inode)
 851 {
 852         struct super_block *sb = inode->i_sb;
 853
 854         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
 855
 856         while (AFFS_I(inode)->i_pa_cnt) {
 857                 AFFS_I(inode)->i_pa_cnt--;
 858                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
 859         }
 860 }
 861
 862 /* Truncate (or enlarge) a file to the requested size. */
 863
 864 void
 865 affs_truncate(struct inode *inode)
 866 {
 867         struct super_block *sb = inode->i_sb;
 868         u32 ext, ext_key;
 869         u32 last_blk, blkcnt, blk;
 870         u32 size;
 871         struct buffer_head *ext_bh;
 872         int i;
 873
 874         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
 875                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
 876
 877         last_blk = 0;
 878         ext = 0;
 879         if (inode->i_size) {
 880                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
 881                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
 882         }
 883
 884         if (inode->i_size > AFFS_I(inode)->mmu_private) {
 885                 struct address_space *mapping = inode->i_mapping;
 886                 struct page *page;
 887                 void *fsdata = NULL;
 888                 loff_t isize = inode->i_size;
 889                 int res;
 890
 891                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, &page, &fsdata);
 892                 if (!res)
 893                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
 894                 else
 895                         inode->i_size = AFFS_I(inode)->mmu_private;
 896                 mark_inode_dirty(inode);
 897                 return;
 898         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
 899                 return;
 900
 901         // lock cache
 902         ext_bh = affs_get_extblock(inode, ext);
 903         if (IS_ERR(ext_bh)) {
 904                 affs_warning(sb, "truncate",
 905                              "unexpected read error for ext block %u (%ld)",
 906                              ext, PTR_ERR(ext_bh));
 907                 return;
 908         }
 909         if (AFFS_I(inode)->i_lc) {
 910                 /* clear linear cache */
 911                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
 912                 if (AFFS_I(inode)->i_lc_size > i) {
 913                         AFFS_I(inode)->i_lc_size = i;
 914                         for (; i < AFFS_LC_SIZE; i++)
 915                                 AFFS_I(inode)->i_lc[i] = 0;
 916                 }
 917                 /* clear associative cache */
 918                 for (i = 0; i < AFFS_AC_SIZE; i++)
 919                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
 920                                 AFFS_I(inode)->i_ac[i].ext = 0;
 921         }
 922         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 923
 924         blkcnt = AFFS_I(inode)->i_blkcnt;
 925         i = 0;
 926         blk = last_blk;
 927         if (inode->i_size) {
 928                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
 929                 blk++;
 930         } else
 931                 AFFS_HEAD(ext_bh)->first_data = 0;
 932         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
 933         size = AFFS_SB(sb)->s_hashsize;
 934         if (size > blkcnt - blk + i)
 935                 size = blkcnt - blk + i;
 936         for (; i < size; i++, blk++) {
 937                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 938                 AFFS_BLOCK(sb, ext_bh, i) = 0;
 939         }
 940         AFFS_TAIL(sb, ext_bh)->extension = 0;
 941         affs_fix_checksum(sb, ext_bh);
 942         mark_buffer_dirty_inode(ext_bh, inode);
 943         affs_brelse(ext_bh);
 944
 945         if (inode->i_size) {
 946                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
 947                 AFFS_I(inode)->i_extcnt = ext + 1;
 948                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
 949                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 950                         u32 tmp;
 951                         if (IS_ERR(bh)) {
 952                                 affs_warning(sb, "truncate",
 953                                              "unexpected read error for last block %u (%ld)",
 954                                              ext, PTR_ERR(bh));
 955                                 return;
 956                         }
 957                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
 958                         AFFS_DATA_HEAD(bh)->next = 0;
 959                         affs_adjust_checksum(bh, -tmp);
 960                         affs_brelse(bh);
 961                 }
 962         } else {
 963                 AFFS_I(inode)->i_blkcnt = 0;
 964                 AFFS_I(inode)->i_extcnt = 1;
 965         }
 966         AFFS_I(inode)->mmu_private = inode->i_size;
 967         // unlock cache
 968
 969         while (ext_key) {
 970                 ext_bh = affs_bread(sb, ext_key);
 971                 size = AFFS_SB(sb)->s_hashsize;
 972                 if (size > blkcnt - blk)
 973                         size = blkcnt - blk;
 974                 for (i = 0; i < size; i++, blk++)
 975                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
 976                 affs_free_block(sb, ext_key);
 977                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 978                 affs_brelse(ext_bh);
 979         }
 980         affs_free_prealloc(inode);
 981 }
 982
 983 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 984 {
 985         struct inode *inode = filp->f_mapping->host;
 986         int ret, err;
 987
 988         err = file_write_and_wait_range(filp, start, end);
 989         if (err)
 990                 return err;
 991
 992         inode_lock(inode);
 993         ret = write_inode_now(inode, 0);
 994         err = sync_blockdev(inode->i_sb->s_bdev);
 995         if (!ret)
 996                 ret = err;
 997         inode_unlock(inode);
 998         return ret;
 999 }
1000 const struct file_operations affs_file_operations = {
1001         .llseek         = generic_file_llseek,
1002         .read_iter      = generic_file_read_iter,
1003         .write_iter     = generic_file_write_iter,
1004         .mmap           = generic_file_mmap,
1005         .open           = affs_file_open,
1006         .release        = affs_file_release,
1007         .fsync          = affs_file_fsync,
1008         .splice_read    = filemap_splice_read,
1009 };
1010
1011 const struct inode_operations affs_file_inode_operations = {
1012         .setattr        = affs_notify_change,
1013 };