Merge tag 'drm-intel-gt-next-2020-11-12-1' of git://anongit.freedesktop.org/drm/drm...
[linux-2.6-microblaze.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_readpage(struct file *file, struct page *page)
379 {
380         return block_read_full_page(page, 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, unsigned flags,
418                         struct page **pagep, void **fsdata)
419 {
420         int ret;
421
422         *pagep = NULL;
423         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
424                                 affs_get_block,
425                                 &AFFS_I(mapping->host)->mmu_private);
426         if (unlikely(ret))
427                 affs_write_failed(mapping, pos + len);
428
429         return ret;
430 }
431
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         .readpage = affs_readpage,
457         .writepage = affs_writepage,
458         .write_begin = affs_write_begin,
459         .write_end = affs_write_end,
460         .direct_IO = affs_direct_IO,
461         .bmap = _affs_bmap
462 };
463
464 static inline struct buffer_head *
465 affs_bread_ino(struct inode *inode, int block, int create)
466 {
467         struct buffer_head *bh, tmp_bh;
468         int err;
469
470         tmp_bh.b_state = 0;
471         err = affs_get_block(inode, block, &tmp_bh, create);
472         if (!err) {
473                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
474                 if (bh) {
475                         bh->b_state |= tmp_bh.b_state;
476                         return bh;
477                 }
478                 err = -EIO;
479         }
480         return ERR_PTR(err);
481 }
482
483 static inline struct buffer_head *
484 affs_getzeroblk_ino(struct inode *inode, int block)
485 {
486         struct buffer_head *bh, tmp_bh;
487         int err;
488
489         tmp_bh.b_state = 0;
490         err = affs_get_block(inode, block, &tmp_bh, 1);
491         if (!err) {
492                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
493                 if (bh) {
494                         bh->b_state |= tmp_bh.b_state;
495                         return bh;
496                 }
497                 err = -EIO;
498         }
499         return ERR_PTR(err);
500 }
501
502 static inline struct buffer_head *
503 affs_getemptyblk_ino(struct inode *inode, int block)
504 {
505         struct buffer_head *bh, tmp_bh;
506         int err;
507
508         tmp_bh.b_state = 0;
509         err = affs_get_block(inode, block, &tmp_bh, 1);
510         if (!err) {
511                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
512                 if (bh) {
513                         bh->b_state |= tmp_bh.b_state;
514                         return bh;
515                 }
516                 err = -EIO;
517         }
518         return ERR_PTR(err);
519 }
520
521 static int
522 affs_do_readpage_ofs(struct page *page, unsigned to, int create)
523 {
524         struct inode *inode = page->mapping->host;
525         struct super_block *sb = inode->i_sb;
526         struct buffer_head *bh;
527         char *data;
528         unsigned pos = 0;
529         u32 bidx, boff, bsize;
530         u32 tmp;
531
532         pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
533                  page->index, to);
534         BUG_ON(to > PAGE_SIZE);
535         bsize = AFFS_SB(sb)->s_data_blksize;
536         tmp = page->index << PAGE_SHIFT;
537         bidx = tmp / bsize;
538         boff = tmp % bsize;
539
540         while (pos < to) {
541                 bh = affs_bread_ino(inode, bidx, create);
542                 if (IS_ERR(bh))
543                         return PTR_ERR(bh);
544                 tmp = min(bsize - boff, to - pos);
545                 BUG_ON(pos + tmp > to || tmp > bsize);
546                 data = kmap_atomic(page);
547                 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
548                 kunmap_atomic(data);
549                 affs_brelse(bh);
550                 bidx++;
551                 pos += tmp;
552                 boff = 0;
553         }
554         flush_dcache_page(page);
555         return 0;
556 }
557
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
630 affs_readpage_ofs(struct file *file, struct page *page)
631 {
632         struct inode *inode = page->mapping->host;
633         u32 to;
634         int err;
635
636         pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
637         to = PAGE_SIZE;
638         if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
639                 to = inode->i_size & ~PAGE_MASK;
640                 memset(page_address(page) + to, 0, PAGE_SIZE - to);
641         }
642
643         err = affs_do_readpage_ofs(page, to, 0);
644         if (!err)
645                 SetPageUptodate(page);
646         unlock_page(page);
647         return err;
648 }
649
650 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
651                                 loff_t pos, unsigned len, unsigned flags,
652                                 struct page **pagep, void **fsdata)
653 {
654         struct inode *inode = mapping->host;
655         struct page *page;
656         pgoff_t index;
657         int err = 0;
658
659         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
660                  pos + len);
661         if (pos > AFFS_I(inode)->mmu_private) {
662                 /* XXX: this probably leaves a too-big i_size in case of
663                  * failure. Should really be updating i_size at write_end time
664                  */
665                 err = affs_extent_file_ofs(inode, pos);
666                 if (err)
667                         return err;
668         }
669
670         index = pos >> PAGE_SHIFT;
671         page = grab_cache_page_write_begin(mapping, index, flags);
672         if (!page)
673                 return -ENOMEM;
674         *pagep = page;
675
676         if (PageUptodate(page))
677                 return 0;
678
679         /* XXX: inefficient but safe in the face of short writes */
680         err = affs_do_readpage_ofs(page, PAGE_SIZE, 1);
681         if (err) {
682                 unlock_page(page);
683                 put_page(page);
684         }
685         return err;
686 }
687
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 inode *inode = mapping->host;
693         struct super_block *sb = inode->i_sb;
694         struct buffer_head *bh, *prev_bh;
695         char *data;
696         u32 bidx, boff, bsize;
697         unsigned from, to;
698         u32 tmp;
699         int written;
700
701         from = pos & (PAGE_SIZE - 1);
702         to = from + len;
703         /*
704          * XXX: not sure if this can handle short copies (len < copied), but
705          * we don't have to, because the page should always be uptodate here,
706          * due to write_begin.
707          */
708
709         pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
710                  pos + len);
711         bsize = AFFS_SB(sb)->s_data_blksize;
712         data = page_address(page);
713
714         bh = NULL;
715         written = 0;
716         tmp = (page->index << PAGE_SHIFT) + from;
717         bidx = tmp / bsize;
718         boff = tmp % bsize;
719         if (boff) {
720                 bh = affs_bread_ino(inode, bidx, 0);
721                 if (IS_ERR(bh)) {
722                         written = PTR_ERR(bh);
723                         goto err_first_bh;
724                 }
725                 tmp = min(bsize - boff, to - from);
726                 BUG_ON(boff + tmp > bsize || tmp > bsize);
727                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
728                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
729                 affs_fix_checksum(sb, bh);
730                 mark_buffer_dirty_inode(bh, inode);
731                 written += tmp;
732                 from += tmp;
733                 bidx++;
734         } else if (bidx) {
735                 bh = affs_bread_ino(inode, bidx - 1, 0);
736                 if (IS_ERR(bh)) {
737                         written = PTR_ERR(bh);
738                         goto err_first_bh;
739                 }
740         }
741         while (from + bsize <= to) {
742                 prev_bh = bh;
743                 bh = affs_getemptyblk_ino(inode, bidx);
744                 if (IS_ERR(bh))
745                         goto err_bh;
746                 memcpy(AFFS_DATA(bh), data + from, bsize);
747                 if (buffer_new(bh)) {
748                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
749                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
750                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
751                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
752                         AFFS_DATA_HEAD(bh)->next = 0;
753                         bh->b_state &= ~(1UL << BH_New);
754                         if (prev_bh) {
755                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
756
757                                 if (tmp_next)
758                                         affs_warning(sb, "commit_write_ofs",
759                                                      "next block already set for %d (%d)",
760                                                      bidx, tmp_next);
761                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
762                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
763                                 mark_buffer_dirty_inode(prev_bh, inode);
764                         }
765                 }
766                 affs_brelse(prev_bh);
767                 affs_fix_checksum(sb, bh);
768                 mark_buffer_dirty_inode(bh, inode);
769                 written += bsize;
770                 from += bsize;
771                 bidx++;
772         }
773         if (from < to) {
774                 prev_bh = bh;
775                 bh = affs_bread_ino(inode, bidx, 1);
776                 if (IS_ERR(bh))
777                         goto err_bh;
778                 tmp = min(bsize, to - from);
779                 BUG_ON(tmp > bsize);
780                 memcpy(AFFS_DATA(bh), data + from, tmp);
781                 if (buffer_new(bh)) {
782                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
783                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
784                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
785                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
786                         AFFS_DATA_HEAD(bh)->next = 0;
787                         bh->b_state &= ~(1UL << BH_New);
788                         if (prev_bh) {
789                                 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
790
791                                 if (tmp_next)
792                                         affs_warning(sb, "commit_write_ofs",
793                                                      "next block already set for %d (%d)",
794                                                      bidx, tmp_next);
795                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
796                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
797                                 mark_buffer_dirty_inode(prev_bh, inode);
798                         }
799                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
800                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
801                 affs_brelse(prev_bh);
802                 affs_fix_checksum(sb, bh);
803                 mark_buffer_dirty_inode(bh, inode);
804                 written += tmp;
805                 from += tmp;
806                 bidx++;
807         }
808         SetPageUptodate(page);
809
810 done:
811         affs_brelse(bh);
812         tmp = (page->index << PAGE_SHIFT) + from;
813         if (tmp > inode->i_size)
814                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
815
816         /* Clear Archived bit on file writes, as AmigaOS would do */
817         if (AFFS_I(inode)->i_protect & FIBF_ARCHIVED) {
818                 AFFS_I(inode)->i_protect &= ~FIBF_ARCHIVED;
819                 mark_inode_dirty(inode);
820         }
821
822 err_first_bh:
823         unlock_page(page);
824         put_page(page);
825
826         return written;
827
828 err_bh:
829         bh = prev_bh;
830         if (!written)
831                 written = PTR_ERR(bh);
832         goto done;
833 }
834
835 const struct address_space_operations affs_aops_ofs = {
836         .readpage = affs_readpage_ofs,
837         //.writepage = affs_writepage_ofs,
838         .write_begin = affs_write_begin_ofs,
839         .write_end = affs_write_end_ofs
840 };
841
842 /* Free any preallocated blocks. */
843
844 void
845 affs_free_prealloc(struct inode *inode)
846 {
847         struct super_block *sb = inode->i_sb;
848
849         pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
850
851         while (AFFS_I(inode)->i_pa_cnt) {
852                 AFFS_I(inode)->i_pa_cnt--;
853                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
854         }
855 }
856
857 /* Truncate (or enlarge) a file to the requested size. */
858
859 void
860 affs_truncate(struct inode *inode)
861 {
862         struct super_block *sb = inode->i_sb;
863         u32 ext, ext_key;
864         u32 last_blk, blkcnt, blk;
865         u32 size;
866         struct buffer_head *ext_bh;
867         int i;
868
869         pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
870                  inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
871
872         last_blk = 0;
873         ext = 0;
874         if (inode->i_size) {
875                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
876                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
877         }
878
879         if (inode->i_size > AFFS_I(inode)->mmu_private) {
880                 struct address_space *mapping = inode->i_mapping;
881                 struct page *page;
882                 void *fsdata;
883                 loff_t isize = inode->i_size;
884                 int res;
885
886                 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
887                 if (!res)
888                         res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
889                 else
890                         inode->i_size = AFFS_I(inode)->mmu_private;
891                 mark_inode_dirty(inode);
892                 return;
893         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
894                 return;
895
896         // lock cache
897         ext_bh = affs_get_extblock(inode, ext);
898         if (IS_ERR(ext_bh)) {
899                 affs_warning(sb, "truncate",
900                              "unexpected read error for ext block %u (%ld)",
901                              ext, PTR_ERR(ext_bh));
902                 return;
903         }
904         if (AFFS_I(inode)->i_lc) {
905                 /* clear linear cache */
906                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
907                 if (AFFS_I(inode)->i_lc_size > i) {
908                         AFFS_I(inode)->i_lc_size = i;
909                         for (; i < AFFS_LC_SIZE; i++)
910                                 AFFS_I(inode)->i_lc[i] = 0;
911                 }
912                 /* clear associative cache */
913                 for (i = 0; i < AFFS_AC_SIZE; i++)
914                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
915                                 AFFS_I(inode)->i_ac[i].ext = 0;
916         }
917         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
918
919         blkcnt = AFFS_I(inode)->i_blkcnt;
920         i = 0;
921         blk = last_blk;
922         if (inode->i_size) {
923                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
924                 blk++;
925         } else
926                 AFFS_HEAD(ext_bh)->first_data = 0;
927         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
928         size = AFFS_SB(sb)->s_hashsize;
929         if (size > blkcnt - blk + i)
930                 size = blkcnt - blk + i;
931         for (; i < size; i++, blk++) {
932                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
933                 AFFS_BLOCK(sb, ext_bh, i) = 0;
934         }
935         AFFS_TAIL(sb, ext_bh)->extension = 0;
936         affs_fix_checksum(sb, ext_bh);
937         mark_buffer_dirty_inode(ext_bh, inode);
938         affs_brelse(ext_bh);
939
940         if (inode->i_size) {
941                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
942                 AFFS_I(inode)->i_extcnt = ext + 1;
943                 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
944                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
945                         u32 tmp;
946                         if (IS_ERR(bh)) {
947                                 affs_warning(sb, "truncate",
948                                              "unexpected read error for last block %u (%ld)",
949                                              ext, PTR_ERR(bh));
950                                 return;
951                         }
952                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
953                         AFFS_DATA_HEAD(bh)->next = 0;
954                         affs_adjust_checksum(bh, -tmp);
955                         affs_brelse(bh);
956                 }
957         } else {
958                 AFFS_I(inode)->i_blkcnt = 0;
959                 AFFS_I(inode)->i_extcnt = 1;
960         }
961         AFFS_I(inode)->mmu_private = inode->i_size;
962         // unlock cache
963
964         while (ext_key) {
965                 ext_bh = affs_bread(sb, ext_key);
966                 size = AFFS_SB(sb)->s_hashsize;
967                 if (size > blkcnt - blk)
968                         size = blkcnt - blk;
969                 for (i = 0; i < size; i++, blk++)
970                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
971                 affs_free_block(sb, ext_key);
972                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
973                 affs_brelse(ext_bh);
974         }
975         affs_free_prealloc(inode);
976 }
977
978 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
979 {
980         struct inode *inode = filp->f_mapping->host;
981         int ret, err;
982
983         err = file_write_and_wait_range(filp, start, end);
984         if (err)
985                 return err;
986
987         inode_lock(inode);
988         ret = write_inode_now(inode, 0);
989         err = sync_blockdev(inode->i_sb->s_bdev);
990         if (!ret)
991                 ret = err;
992         inode_unlock(inode);
993         return ret;
994 }
995 const struct file_operations affs_file_operations = {
996         .llseek         = generic_file_llseek,
997         .read_iter      = generic_file_read_iter,
998         .write_iter     = generic_file_write_iter,
999         .mmap           = generic_file_mmap,
1000         .open           = affs_file_open,
1001         .release        = affs_file_release,
1002         .fsync          = affs_file_fsync,
1003         .splice_read    = generic_file_splice_read,
1004 };
1005
1006 const struct inode_operations affs_file_inode_operations = {
1007         .setattr        = affs_notify_change,
1008 };