GNU Linux-libre 5.19-rc6-gnu
[releases.git] / 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 "affs.h"
19
20 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
21
22 static int
23 affs_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
31 static int
32 affs_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
48 static int
49 affs_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
113 err:
114         // lock cache
115         return -EIO;
116 }
117
118 static struct buffer_head *
119 affs_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
156 static inline struct buffer_head *
157 affs_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
170 static struct buffer_head *
171 affs_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
215 again:
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];
255 find_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
273 read_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
281 store_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
290 err_bread:
291         affs_brelse(bh);
292         return ERR_PTR(-EIO);
293 }
294
295 static int
296 affs_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
356 err_big:
357         affs_error(inode->i_sb, "get_block", "strange block request %llu",
358                    (unsigned long long)block);
359         return -EIO;
360 err_ext:
361         // unlock cache
362         affs_unlock_ext(inode);
363         return PTR_ERR(ext_bh);
364 err_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
373 static int affs_writepage(struct page *page, struct writeback_control *wbc)
374 {
375         return block_write_full_page(page, affs_get_block, wbc);
376 }
377
378 static int affs_read_folio(struct file *file, struct folio *folio)
379 {
380         return block_read_full_folio(folio, affs_get_block);
381 }
382
383 static 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
393 static ssize_t
394 affs_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
416 static int affs_write_begin(struct file *file, struct address_space *mapping,
417                         loff_t pos, unsigned len,
418                         struct page **pagep, void **fsdata)
419 {
420         int ret;
421
422         *pagep = NULL;
423         ret = cont_write_begin(file, mapping, pos, len, 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
432 static 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
450 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
451 {
452         return generic_block_bmap(mapping,block,affs_get_block);
453 }
454
455 const struct address_space_operations affs_aops = {
456         .dirty_folio    = block_dirty_folio,
457         .invalidate_folio = block_invalidate_folio,
458         .read_folio = affs_read_folio,
459         .writepage = affs_writepage,
460         .write_begin = affs_write_begin,
461         .write_end = affs_write_end,
462         .direct_IO = affs_direct_IO,
463         .bmap = _affs_bmap
464 };
465
466 static inline struct buffer_head *
467 affs_bread_ino(struct inode *inode, int block, int create)
468 {
469         struct buffer_head *bh, tmp_bh;
470         int err;
471
472         tmp_bh.b_state = 0;
473         err = affs_get_block(inode, block, &tmp_bh, create);
474         if (!err) {
475                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
476                 if (bh) {
477                         bh->b_state |= tmp_bh.b_state;
478                         return bh;
479                 }
480                 err = -EIO;
481         }
482         return ERR_PTR(err);
483 }
484
485 static inline struct buffer_head *
486 affs_getzeroblk_ino(struct inode *inode, int block)
487 {
488         struct buffer_head *bh, tmp_bh;
489         int err;
490
491         tmp_bh.b_state = 0;
492         err = affs_get_block(inode, block, &tmp_bh, 1);
493         if (!err) {
494                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
495                 if (bh) {
496                         bh->b_state |= tmp_bh.b_state;
497                         return bh;
498                 }
499                 err = -EIO;
500         }
501         return ERR_PTR(err);
502 }
503
504 static inline struct buffer_head *
505 affs_getemptyblk_ino(struct inode *inode, int block)
506 {
507         struct buffer_head *bh, tmp_bh;
508         int err;
509
510         tmp_bh.b_state = 0;
511         err = affs_get_block(inode, block, &tmp_bh, 1);
512         if (!err) {
513                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
514                 if (bh) {
515                         bh->b_state |= tmp_bh.b_state;
516                         return bh;
517                 }
518                 err = -EIO;
519         }
520         return ERR_PTR(err);
521 }
522
523 static int
524 affs_do_readpage_ofs(struct page *page, unsigned to, int create)
525 {
526         struct inode *inode = page->mapping->host;
527         struct super_block *sb = inode->i_sb;
528         struct buffer_head *bh;
529         char *data;
530         unsigned pos = 0;
531         u32 bidx, boff, bsize;
532         u32 tmp;
533
534         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
535                  page->index, to);
536         BUG_ON(to > PAGE_SIZE);
537         bsize = AFFS_SB(sb)->s_data_blksize;
538         tmp = page->index << PAGE_SHIFT;
539         bidx = tmp / bsize;
540         boff = tmp % bsize;
541
542         while (pos < to) {
543                 bh = affs_bread_ino(inode, bidx, create);
544                 if (IS_ERR(bh))
545                         return PTR_ERR(bh);
546                 tmp = min(bsize - boff, to - pos);
547                 BUG_ON(pos + tmp > to || tmp > bsize);
548                 data = kmap_atomic(page);
549                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
550                 kunmap_atomic(data);
551                 affs_brelse(bh);
552                 bidx++;
553                 pos += tmp;
554                 boff = 0;
555         }
556         flush_dcache_page(page);
557         return 0;
558 }
559
560 static int
561 affs_extent_file_ofs(struct inode *inode, u32 newsize)
562 {
563         struct super_block *sb = inode->i_sb;
564         struct buffer_head *bh, *prev_bh;
565         u32 bidx, boff;
566         u32 size, bsize;
567         u32 tmp;
568
569         pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
570         bsize = AFFS_SB(sb)->s_data_blksize;
571         bh = NULL;
572         size = AFFS_I(inode)->mmu_private;
573         bidx = size / bsize;
574         boff = size % bsize;
575         if (boff) {
576                 bh = affs_bread_ino(inode, bidx, 0);
577                 if (IS_ERR(bh))
578                         return PTR_ERR(bh);
579                 tmp = min(bsize - boff, newsize - size);
580                 BUG_ON(boff + tmp > bsize || tmp > bsize);
581                 memset(AFFS_DATA(bh) + boff, 0, tmp);
582                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
583                 affs_fix_checksum(sb, bh);
584                 mark_buffer_dirty_inode(bh, inode);
585                 size += tmp;
586                 bidx++;
587         } else if (bidx) {
588                 bh = affs_bread_ino(inode, bidx - 1, 0);
589                 if (IS_ERR(bh))
590                         return PTR_ERR(bh);
591         }
592
593         while (size < newsize) {
594                 prev_bh = bh;
595                 bh = affs_getzeroblk_ino(inode, bidx);
596                 if (IS_ERR(bh))
597                         goto out;
598                 tmp = min(bsize, newsize - size);
599                 BUG_ON(tmp > bsize);
600                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
601                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
602                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
603                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
604                 affs_fix_checksum(sb, bh);
605                 bh->b_state &= ~(1UL << BH_New);
606                 mark_buffer_dirty_inode(bh, inode);
607                 if (prev_bh) {
608                         u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
609
610                         if (tmp_next)
611                                 affs_warning(sb, "extent_file_ofs",
612                                              "next block already set for %d (%d)",
613                                              bidx, tmp_next);
614                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
615                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
616                         mark_buffer_dirty_inode(prev_bh, inode);
617                         affs_brelse(prev_bh);
618                 }
619                 size += bsize;
620                 bidx++;
621         }
622         affs_brelse(bh);
623         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
624         return 0;
625
626 out:
627         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
628         return PTR_ERR(bh);
629 }
630
631 static int
632 affs_read_folio_ofs(struct file *file, struct folio *folio)
633 {
634         struct page *page = &folio->page;
635         struct inode *inode = page->mapping->host;
636         u32 to;
637         int err;
638
639         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
640         to = PAGE_SIZE;
641         if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
642                 to = inode->i_size & ~PAGE_MASK;
643                 memset(page_address(page) + to, 0, PAGE_SIZE - to);
644         }
645
646         err = affs_do_readpage_ofs(page, to, 0);
647         if (!err)
648                 SetPageUptodate(page);
649         unlock_page(page);
650         return err;
651 }
652
653 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
654                                 loff_t pos, unsigned len,
655                                 struct page **pagep, void **fsdata)
656 {
657         struct inode *inode = mapping->host;
658         struct page *page;
659         pgoff_t index;
660         int err = 0;
661
662         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
663                  pos + len);
664         if (pos > AFFS_I(inode)->mmu_private) {
665                 /* XXX: this probably leaves a too-big i_size in case of
666                  * failure. Should really be updating i_size at write_end time
667                  */
668                 err = affs_extent_file_ofs(inode, pos);
669                 if (err)
670                         return err;
671         }
672
673         index = pos >> PAGE_SHIFT;
674         page = grab_cache_page_write_begin(mapping, index);
675         if (!page)
676                 return -ENOMEM;
677         *pagep = page;
678
679         if (PageUptodate(page))
680                 return 0;
681
682         /* XXX: inefficient but safe in the face of short writes */
683         err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
684         if (err) {
685                 unlock_page(page);
686                 put_page(page);
687         }
688         return err;
689 }
690
691 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
692                                 loff_t pos, unsigned len, unsigned copied,
693                                 struct page *page, void *fsdata)
694 {
695         struct inode *inode = mapping->host;
696         struct super_block *sb = inode->i_sb;
697         struct buffer_head *bh, *prev_bh;
698         char *data;
699         u32 bidx, boff, bsize;
700         unsigned from, to;
701         u32 tmp;
702         int written;
703
704         from = pos & (PAGE_SIZE - 1);
705         to = from + len;
706         /*
707          * XXX: not sure if this can handle short copies (len < copied), but
708          * we don't have to, because the page should always be uptodate here,
709          * due to write_begin.
710          */
711
712         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
713                  pos + len);
714         bsize = AFFS_SB(sb)->s_data_blksize;
715         data = page_address(page);
716
717         bh = NULL;
718         written = 0;
719         tmp = (page->index << PAGE_SHIFT) + from;
720         bidx = tmp / bsize;
721         boff = tmp % bsize;
722         if (boff) {
723                 bh = affs_bread_ino(inode, bidx, 0);
724                 if (IS_ERR(bh)) {
725                         written = PTR_ERR(bh);
726                         goto err_first_bh;
727                 }
728                 tmp = min(bsize - boff, to - from);
729                 BUG_ON(boff + tmp > bsize || tmp > bsize);
730                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
731                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
732                 affs_fix_checksum(sb, bh);
733                 mark_buffer_dirty_inode(bh, inode);
734                 written += tmp;
735                 from += tmp;
736                 bidx++;
737         } else if (bidx) {
738                 bh = affs_bread_ino(inode, bidx - 1, 0);
739                 if (IS_ERR(bh)) {
740                         written = PTR_ERR(bh);
741                         goto err_first_bh;
742                 }
743         }
744         while (from + bsize <= to) {
745                 prev_bh = bh;
746                 bh = affs_getemptyblk_ino(inode, bidx);
747                 if (IS_ERR(bh))
748                         goto err_bh;
749                 memcpy(AFFS_DATA(bh), data + from, bsize);
750                 if (buffer_new(bh)) {
751                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
752                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
753                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
754                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
755                         AFFS_DATA_HEAD(bh)->next = 0;
756                         bh->b_state &= ~(1UL << BH_New);
757                         if (prev_bh) {
758                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
759
760                                 if (tmp_next)
761                                         affs_warning(sb, "commit_write_ofs",
762                                                      "next block already set for %d (%d)",
763                                                      bidx, tmp_next);
764                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
765                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
766                                 mark_buffer_dirty_inode(prev_bh, inode);
767                         }
768                 }
769                 affs_brelse(prev_bh);
770                 affs_fix_checksum(sb, bh);
771                 mark_buffer_dirty_inode(bh, inode);
772                 written += bsize;
773                 from += bsize;
774                 bidx++;
775         }
776         if (from < to) {
777                 prev_bh = bh;
778                 bh = affs_bread_ino(inode, bidx, 1);
779                 if (IS_ERR(bh))
780                         goto err_bh;
781                 tmp = min(bsize, to - from);
782                 BUG_ON(tmp > bsize);
783                 memcpy(AFFS_DATA(bh), data + from, tmp);
784                 if (buffer_new(bh)) {
785                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
786                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
787                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
788                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
789                         AFFS_DATA_HEAD(bh)->next = 0;
790                         bh->b_state &= ~(1UL << BH_New);
791                         if (prev_bh) {
792                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
793
794                                 if (tmp_next)
795                                         affs_warning(sb, "commit_write_ofs",
796                                                      "next block already set for %d (%d)",
797                                                      bidx, tmp_next);
798                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
799                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
800                                 mark_buffer_dirty_inode(prev_bh, inode);
801                         }
802                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
803                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
804                 affs_brelse(prev_bh);
805                 affs_fix_checksum(sb, bh);
806                 mark_buffer_dirty_inode(bh, inode);
807                 written += tmp;
808                 from += tmp;
809                 bidx++;
810         }
811         SetPageUptodate(page);
812
813 done:
814         affs_brelse(bh);
815         tmp = (page->index << PAGE_SHIFT) + from;
816         if (tmp > inode->i_size)
817                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
818
819         /* Clear Archived bit on file writes, as AmigaOS would do */
820         if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
821                 AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
822                 mark_inode_dirty(inode);
823         }
824
825 err_first_bh:
826         unlock_page(page);
827         put_page(page);
828
829         return written;
830
831 err_bh:
832         bh = prev_bh;
833         if (!written)
834                 written = PTR_ERR(bh);
835         goto done;
836 }
837
838 const struct address_space_operations affs_aops_ofs = {
839         .dirty_folio    = block_dirty_folio,
840         .invalidate_folio = block_invalidate_folio,
841         .read_folio = affs_read_folio_ofs,
842         //.writepage = affs_writepage_ofs,
843         .write_begin = affs_write_begin_ofs,
844         .write_end = affs_write_end_ofs
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;
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    = generic_file_splice_read,
1009 };
1010
1011 const struct inode_operations affs_file_inode_operations = {
1012         .setattr        = affs_notify_change,
1013 };