Merge rsync://bughost.org/repos/ipw-delta/
[linux-2.6] / fs / affs / file.c
1 /*
2  *  linux/fs/affs/file.c
3  *
4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
5  *
6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
7  *
8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
9  *
10  *  (C) 1991  Linus Torvalds - minix filesystem
11  *
12  *  affs regular file handling primitives
13  */
14
15 #include "affs.h"
16
17 #if PAGE_SIZE < 4096
18 #error PAGE_SIZE must be at least 4096
19 #endif
20
21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
25 static int affs_file_open(struct inode *inode, struct file *filp);
26 static int affs_file_release(struct inode *inode, struct file *filp);
27
28 struct file_operations affs_file_operations = {
29         .llseek         = generic_file_llseek,
30         .read           = generic_file_read,
31         .write          = generic_file_write,
32         .mmap           = generic_file_mmap,
33         .open           = affs_file_open,
34         .release        = affs_file_release,
35         .fsync          = file_fsync,
36         .sendfile       = generic_file_sendfile,
37 };
38
39 struct inode_operations affs_file_inode_operations = {
40         .truncate       = affs_truncate,
41         .setattr        = affs_notify_change,
42 };
43
44 static int
45 affs_file_open(struct inode *inode, struct file *filp)
46 {
47         if (atomic_read(&filp->f_count) != 1)
48                 return 0;
49         pr_debug("AFFS: open(%d)\n", AFFS_I(inode)->i_opencnt);
50         AFFS_I(inode)->i_opencnt++;
51         return 0;
52 }
53
54 static int
55 affs_file_release(struct inode *inode, struct file *filp)
56 {
57         if (atomic_read(&filp->f_count) != 0)
58                 return 0;
59         pr_debug("AFFS: release(%d)\n", AFFS_I(inode)->i_opencnt);
60         AFFS_I(inode)->i_opencnt--;
61         if (!AFFS_I(inode)->i_opencnt)
62                 affs_free_prealloc(inode);
63
64         return 0;
65 }
66
67 static int
68 affs_grow_extcache(struct inode *inode, u32 lc_idx)
69 {
70         struct super_block      *sb = inode->i_sb;
71         struct buffer_head      *bh;
72         u32 lc_max;
73         int i, j, key;
74
75         if (!AFFS_I(inode)->i_lc) {
76                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
77                 if (!ptr)
78                         return -ENOMEM;
79                 AFFS_I(inode)->i_lc = (u32 *)ptr;
80                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
81         }
82
83         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
84
85         if (AFFS_I(inode)->i_extcnt > lc_max) {
86                 u32 lc_shift, lc_mask, tmp, off;
87
88                 /* need to recalculate linear cache, start from old size */
89                 lc_shift = AFFS_I(inode)->i_lc_shift;
90                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
91                 for (; tmp; tmp >>= 1)
92                         lc_shift++;
93                 lc_mask = (1 << lc_shift) - 1;
94
95                 /* fix idx and old size to new shift */
96                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
97                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
98
99                 /* first shrink old cache to make more space */
100                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
101                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
102                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
103
104                 AFFS_I(inode)->i_lc_shift = lc_shift;
105                 AFFS_I(inode)->i_lc_mask = lc_mask;
106         }
107
108         /* fill cache to the needed index */
109         i = AFFS_I(inode)->i_lc_size;
110         AFFS_I(inode)->i_lc_size = lc_idx + 1;
111         for (; i <= lc_idx; i++) {
112                 if (!i) {
113                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
114                         continue;
115                 }
116                 key = AFFS_I(inode)->i_lc[i - 1];
117                 j = AFFS_I(inode)->i_lc_mask + 1;
118                 // unlock cache
119                 for (; j > 0; j--) {
120                         bh = affs_bread(sb, key);
121                         if (!bh)
122                                 goto err;
123                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
124                         affs_brelse(bh);
125                 }
126                 // lock cache
127                 AFFS_I(inode)->i_lc[i] = key;
128         }
129
130         return 0;
131
132 err:
133         // lock cache
134         return -EIO;
135 }
136
137 static struct buffer_head *
138 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
139 {
140         struct super_block *sb = inode->i_sb;
141         struct buffer_head *new_bh;
142         u32 blocknr, tmp;
143
144         blocknr = affs_alloc_block(inode, bh->b_blocknr);
145         if (!blocknr)
146                 return ERR_PTR(-ENOSPC);
147
148         new_bh = affs_getzeroblk(sb, blocknr);
149         if (!new_bh) {
150                 affs_free_block(sb, blocknr);
151                 return ERR_PTR(-EIO);
152         }
153
154         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
155         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
156         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
157         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
158         affs_fix_checksum(sb, new_bh);
159
160         mark_buffer_dirty_inode(new_bh, inode);
161
162         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
163         if (tmp)
164                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
165         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
166         affs_adjust_checksum(bh, blocknr - tmp);
167         mark_buffer_dirty_inode(bh, inode);
168
169         AFFS_I(inode)->i_extcnt++;
170         mark_inode_dirty(inode);
171
172         return new_bh;
173 }
174
175 static inline struct buffer_head *
176 affs_get_extblock(struct inode *inode, u32 ext)
177 {
178         /* inline the simplest case: same extended block as last time */
179         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
180         if (ext == AFFS_I(inode)->i_ext_last)
181                 atomic_inc(&bh->b_count);
182         else
183                 /* we have to do more (not inlined) */
184                 bh = affs_get_extblock_slow(inode, ext);
185
186         return bh;
187 }
188
189 static struct buffer_head *
190 affs_get_extblock_slow(struct inode *inode, u32 ext)
191 {
192         struct super_block *sb = inode->i_sb;
193         struct buffer_head *bh;
194         u32 ext_key;
195         u32 lc_idx, lc_off, ac_idx;
196         u32 tmp, idx;
197
198         if (ext == AFFS_I(inode)->i_ext_last + 1) {
199                 /* read the next extended block from the current one */
200                 bh = AFFS_I(inode)->i_ext_bh;
201                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
202                 if (ext < AFFS_I(inode)->i_extcnt)
203                         goto read_ext;
204                 if (ext > AFFS_I(inode)->i_extcnt)
205                         BUG();
206                 bh = affs_alloc_extblock(inode, bh, ext);
207                 if (IS_ERR(bh))
208                         return bh;
209                 goto store_ext;
210         }
211
212         if (ext == 0) {
213                 /* we seek back to the file header block */
214                 ext_key = inode->i_ino;
215                 goto read_ext;
216         }
217
218         if (ext >= AFFS_I(inode)->i_extcnt) {
219                 struct buffer_head *prev_bh;
220
221                 /* allocate a new extended block */
222                 if (ext > AFFS_I(inode)->i_extcnt)
223                         BUG();
224
225                 /* get previous extended block */
226                 prev_bh = affs_get_extblock(inode, ext - 1);
227                 if (IS_ERR(prev_bh))
228                         return prev_bh;
229                 bh = affs_alloc_extblock(inode, prev_bh, ext);
230                 affs_brelse(prev_bh);
231                 if (IS_ERR(bh))
232                         return bh;
233                 goto store_ext;
234         }
235
236 again:
237         /* check if there is an extended cache and whether it's large enough */
238         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
239         lc_off = ext & AFFS_I(inode)->i_lc_mask;
240
241         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
242                 int err;
243
244                 err = affs_grow_extcache(inode, lc_idx);
245                 if (err)
246                         return ERR_PTR(err);
247                 goto again;
248         }
249
250         /* every n'th key we find in the linear cache */
251         if (!lc_off) {
252                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
253                 goto read_ext;
254         }
255
256         /* maybe it's still in the associative cache */
257         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
258         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
259                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
260                 goto read_ext;
261         }
262
263         /* try to find one of the previous extended blocks */
264         tmp = ext;
265         idx = ac_idx;
266         while (--tmp, --lc_off > 0) {
267                 idx = (idx - 1) & AFFS_AC_MASK;
268                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
269                         ext_key = AFFS_I(inode)->i_ac[idx].key;
270                         goto find_ext;
271                 }
272         }
273
274         /* fall back to the linear cache */
275         ext_key = AFFS_I(inode)->i_lc[lc_idx];
276 find_ext:
277         /* read all extended blocks until we find the one we need */
278         //unlock cache
279         do {
280                 bh = affs_bread(sb, ext_key);
281                 if (!bh)
282                         goto err_bread;
283                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
284                 affs_brelse(bh);
285                 tmp++;
286         } while (tmp < ext);
287         //lock cache
288
289         /* store it in the associative cache */
290         // recalculate ac_idx?
291         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
292         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
293
294 read_ext:
295         /* finally read the right extended block */
296         //unlock cache
297         bh = affs_bread(sb, ext_key);
298         if (!bh)
299                 goto err_bread;
300         //lock cache
301
302 store_ext:
303         /* release old cached extended block and store the new one */
304         affs_brelse(AFFS_I(inode)->i_ext_bh);
305         AFFS_I(inode)->i_ext_last = ext;
306         AFFS_I(inode)->i_ext_bh = bh;
307         atomic_inc(&bh->b_count);
308
309         return bh;
310
311 err_bread:
312         affs_brelse(bh);
313         return ERR_PTR(-EIO);
314 }
315
316 static int
317 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
318 {
319         struct super_block      *sb = inode->i_sb;
320         struct buffer_head      *ext_bh;
321         u32                      ext;
322
323         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
324
325
326         if (block > (sector_t)0x7fffffffUL)
327                 BUG();
328
329         if (block >= AFFS_I(inode)->i_blkcnt) {
330                 if (block > AFFS_I(inode)->i_blkcnt || !create)
331                         goto err_big;
332         } else
333                 create = 0;
334
335         //lock cache
336         affs_lock_ext(inode);
337
338         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
339         block -= ext * AFFS_SB(sb)->s_hashsize;
340         ext_bh = affs_get_extblock(inode, ext);
341         if (IS_ERR(ext_bh))
342                 goto err_ext;
343         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
344
345         if (create) {
346                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
347                 if (!blocknr)
348                         goto err_alloc;
349                 set_buffer_new(bh_result);
350                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
351                 AFFS_I(inode)->i_blkcnt++;
352
353                 /* store new block */
354                 if (bh_result->b_blocknr)
355                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
356                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
357                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
358                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
359                 bh_result->b_blocknr = blocknr;
360
361                 if (!block) {
362                         /* insert first block into header block */
363                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
364                         if (tmp)
365                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
366                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
367                         affs_adjust_checksum(ext_bh, blocknr - tmp);
368                 }
369         }
370
371         affs_brelse(ext_bh);
372         //unlock cache
373         affs_unlock_ext(inode);
374         return 0;
375
376 err_big:
377         affs_error(inode->i_sb,"get_block","strange block request %d", block);
378         return -EIO;
379 err_ext:
380         // unlock cache
381         affs_unlock_ext(inode);
382         return PTR_ERR(ext_bh);
383 err_alloc:
384         brelse(ext_bh);
385         clear_buffer_mapped(bh_result);
386         bh_result->b_bdev = NULL;
387         // unlock cache
388         affs_unlock_ext(inode);
389         return -ENOSPC;
390 }
391
392 static int affs_writepage(struct page *page, struct writeback_control *wbc)
393 {
394         return block_write_full_page(page, affs_get_block, wbc);
395 }
396 static int affs_readpage(struct file *file, struct page *page)
397 {
398         return block_read_full_page(page, affs_get_block);
399 }
400 static int affs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
401 {
402         return cont_prepare_write(page, from, to, affs_get_block,
403                 &AFFS_I(page->mapping->host)->mmu_private);
404 }
405 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
406 {
407         return generic_block_bmap(mapping,block,affs_get_block);
408 }
409 struct address_space_operations affs_aops = {
410         .readpage = affs_readpage,
411         .writepage = affs_writepage,
412         .sync_page = block_sync_page,
413         .prepare_write = affs_prepare_write,
414         .commit_write = generic_commit_write,
415         .bmap = _affs_bmap
416 };
417
418 static inline struct buffer_head *
419 affs_bread_ino(struct inode *inode, int block, int create)
420 {
421         struct buffer_head *bh, tmp_bh;
422         int err;
423
424         tmp_bh.b_state = 0;
425         err = affs_get_block(inode, block, &tmp_bh, create);
426         if (!err) {
427                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
428                 if (bh) {
429                         bh->b_state |= tmp_bh.b_state;
430                         return bh;
431                 }
432                 err = -EIO;
433         }
434         return ERR_PTR(err);
435 }
436
437 static inline struct buffer_head *
438 affs_getzeroblk_ino(struct inode *inode, int block)
439 {
440         struct buffer_head *bh, tmp_bh;
441         int err;
442
443         tmp_bh.b_state = 0;
444         err = affs_get_block(inode, block, &tmp_bh, 1);
445         if (!err) {
446                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
447                 if (bh) {
448                         bh->b_state |= tmp_bh.b_state;
449                         return bh;
450                 }
451                 err = -EIO;
452         }
453         return ERR_PTR(err);
454 }
455
456 static inline struct buffer_head *
457 affs_getemptyblk_ino(struct inode *inode, int block)
458 {
459         struct buffer_head *bh, tmp_bh;
460         int err;
461
462         tmp_bh.b_state = 0;
463         err = affs_get_block(inode, block, &tmp_bh, 1);
464         if (!err) {
465                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
466                 if (bh) {
467                         bh->b_state |= tmp_bh.b_state;
468                         return bh;
469                 }
470                 err = -EIO;
471         }
472         return ERR_PTR(err);
473 }
474
475 static int
476 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
477 {
478         struct inode *inode = page->mapping->host;
479         struct super_block *sb = inode->i_sb;
480         struct buffer_head *bh;
481         char *data;
482         u32 bidx, boff, bsize;
483         u32 tmp;
484
485         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
486         if (from > to || to > PAGE_CACHE_SIZE)
487                 BUG();
488         kmap(page);
489         data = page_address(page);
490         bsize = AFFS_SB(sb)->s_data_blksize;
491         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
492         bidx = tmp / bsize;
493         boff = tmp % bsize;
494
495         while (from < to) {
496                 bh = affs_bread_ino(inode, bidx, 0);
497                 if (IS_ERR(bh))
498                         return PTR_ERR(bh);
499                 tmp = min(bsize - boff, to - from);
500                 if (from + tmp > to || tmp > bsize)
501                         BUG();
502                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
503                 affs_brelse(bh);
504                 bidx++;
505                 from += tmp;
506                 boff = 0;
507         }
508         flush_dcache_page(page);
509         kunmap(page);
510         return 0;
511 }
512
513 static int
514 affs_extent_file_ofs(struct inode *inode, u32 newsize)
515 {
516         struct super_block *sb = inode->i_sb;
517         struct buffer_head *bh, *prev_bh;
518         u32 bidx, boff;
519         u32 size, bsize;
520         u32 tmp;
521
522         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
523         bsize = AFFS_SB(sb)->s_data_blksize;
524         bh = NULL;
525         size = AFFS_I(inode)->mmu_private;
526         bidx = size / bsize;
527         boff = size % bsize;
528         if (boff) {
529                 bh = affs_bread_ino(inode, bidx, 0);
530                 if (IS_ERR(bh))
531                         return PTR_ERR(bh);
532                 tmp = min(bsize - boff, newsize - size);
533                 if (boff + tmp > bsize || tmp > bsize)
534                         BUG();
535                 memset(AFFS_DATA(bh) + boff, 0, tmp);
536                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
537                 affs_fix_checksum(sb, bh);
538                 mark_buffer_dirty_inode(bh, inode);
539                 size += tmp;
540                 bidx++;
541         } else if (bidx) {
542                 bh = affs_bread_ino(inode, bidx - 1, 0);
543                 if (IS_ERR(bh))
544                         return PTR_ERR(bh);
545         }
546
547         while (size < newsize) {
548                 prev_bh = bh;
549                 bh = affs_getzeroblk_ino(inode, bidx);
550                 if (IS_ERR(bh))
551                         goto out;
552                 tmp = min(bsize, newsize - size);
553                 if (tmp > bsize)
554                         BUG();
555                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
556                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
557                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
558                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
559                 affs_fix_checksum(sb, bh);
560                 bh->b_state &= ~(1UL << BH_New);
561                 mark_buffer_dirty_inode(bh, inode);
562                 if (prev_bh) {
563                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
564                         if (tmp)
565                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
566                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
567                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
568                         mark_buffer_dirty_inode(prev_bh, inode);
569                         affs_brelse(prev_bh);
570                 }
571                 size += bsize;
572                 bidx++;
573         }
574         affs_brelse(bh);
575         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
576         return 0;
577
578 out:
579         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
580         return PTR_ERR(bh);
581 }
582
583 static int
584 affs_readpage_ofs(struct file *file, struct page *page)
585 {
586         struct inode *inode = page->mapping->host;
587         u32 to;
588         int err;
589
590         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
591         to = PAGE_CACHE_SIZE;
592         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
593                 to = inode->i_size & ~PAGE_CACHE_MASK;
594                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
595         }
596
597         err = affs_do_readpage_ofs(file, page, 0, to);
598         if (!err)
599                 SetPageUptodate(page);
600         unlock_page(page);
601         return err;
602 }
603
604 static int affs_prepare_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
605 {
606         struct inode *inode = page->mapping->host;
607         u32 size, offset;
608         u32 tmp;
609         int err = 0;
610
611         pr_debug("AFFS: prepare_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
612         offset = page->index << PAGE_CACHE_SHIFT;
613         if (offset + from > AFFS_I(inode)->mmu_private) {
614                 err = affs_extent_file_ofs(inode, offset + from);
615                 if (err)
616                         return err;
617         }
618         size = inode->i_size;
619
620         if (PageUptodate(page))
621                 return 0;
622
623         if (from) {
624                 err = affs_do_readpage_ofs(file, page, 0, from);
625                 if (err)
626                         return err;
627         }
628         if (to < PAGE_CACHE_SIZE) {
629                 char *kaddr = kmap_atomic(page, KM_USER0);
630
631                 memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
632                 flush_dcache_page(page);
633                 kunmap_atomic(kaddr, KM_USER0);
634                 if (size > offset + to) {
635                         if (size < offset + PAGE_CACHE_SIZE)
636                                 tmp = size & ~PAGE_CACHE_MASK;
637                         else
638                                 tmp = PAGE_CACHE_SIZE;
639                         err = affs_do_readpage_ofs(file, page, to, tmp);
640                 }
641         }
642         return err;
643 }
644
645 static int affs_commit_write_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
646 {
647         struct inode *inode = page->mapping->host;
648         struct super_block *sb = inode->i_sb;
649         struct buffer_head *bh, *prev_bh;
650         char *data;
651         u32 bidx, boff, bsize;
652         u32 tmp;
653         int written;
654
655         pr_debug("AFFS: commit_write(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
656         bsize = AFFS_SB(sb)->s_data_blksize;
657         data = page_address(page);
658
659         bh = NULL;
660         written = 0;
661         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
662         bidx = tmp / bsize;
663         boff = tmp % bsize;
664         if (boff) {
665                 bh = affs_bread_ino(inode, bidx, 0);
666                 if (IS_ERR(bh))
667                         return PTR_ERR(bh);
668                 tmp = min(bsize - boff, to - from);
669                 if (boff + tmp > bsize || tmp > bsize)
670                         BUG();
671                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
672                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
673                 affs_fix_checksum(sb, bh);
674                 mark_buffer_dirty_inode(bh, inode);
675                 written += tmp;
676                 from += tmp;
677                 bidx++;
678         } else if (bidx) {
679                 bh = affs_bread_ino(inode, bidx - 1, 0);
680                 if (IS_ERR(bh))
681                         return PTR_ERR(bh);
682         }
683         while (from + bsize <= to) {
684                 prev_bh = bh;
685                 bh = affs_getemptyblk_ino(inode, bidx);
686                 if (IS_ERR(bh))
687                         goto out;
688                 memcpy(AFFS_DATA(bh), data + from, bsize);
689                 if (buffer_new(bh)) {
690                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
691                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
692                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
693                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
694                         AFFS_DATA_HEAD(bh)->next = 0;
695                         bh->b_state &= ~(1UL << BH_New);
696                         if (prev_bh) {
697                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
698                                 if (tmp)
699                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
700                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
701                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
702                                 mark_buffer_dirty_inode(prev_bh, inode);
703                         }
704                 }
705                 affs_brelse(prev_bh);
706                 affs_fix_checksum(sb, bh);
707                 mark_buffer_dirty_inode(bh, inode);
708                 written += bsize;
709                 from += bsize;
710                 bidx++;
711         }
712         if (from < to) {
713                 prev_bh = bh;
714                 bh = affs_bread_ino(inode, bidx, 1);
715                 if (IS_ERR(bh))
716                         goto out;
717                 tmp = min(bsize, to - from);
718                 if (tmp > bsize)
719                         BUG();
720                 memcpy(AFFS_DATA(bh), data + from, tmp);
721                 if (buffer_new(bh)) {
722                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
723                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
724                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
725                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
726                         AFFS_DATA_HEAD(bh)->next = 0;
727                         bh->b_state &= ~(1UL << BH_New);
728                         if (prev_bh) {
729                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
730                                 if (tmp)
731                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
732                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
733                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
734                                 mark_buffer_dirty_inode(prev_bh, inode);
735                         }
736                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
737                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
738                 affs_brelse(prev_bh);
739                 affs_fix_checksum(sb, bh);
740                 mark_buffer_dirty_inode(bh, inode);
741                 written += tmp;
742                 from += tmp;
743                 bidx++;
744         }
745         SetPageUptodate(page);
746
747 done:
748         affs_brelse(bh);
749         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
750         if (tmp > inode->i_size)
751                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
752
753         return written;
754
755 out:
756         bh = prev_bh;
757         if (!written)
758                 written = PTR_ERR(bh);
759         goto done;
760 }
761
762 struct address_space_operations affs_aops_ofs = {
763         .readpage = affs_readpage_ofs,
764         //.writepage = affs_writepage_ofs,
765         //.sync_page = affs_sync_page_ofs,
766         .prepare_write = affs_prepare_write_ofs,
767         .commit_write = affs_commit_write_ofs
768 };
769
770 /* Free any preallocated blocks. */
771
772 void
773 affs_free_prealloc(struct inode *inode)
774 {
775         struct super_block *sb = inode->i_sb;
776
777         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
778
779         while (AFFS_I(inode)->i_pa_cnt) {
780                 AFFS_I(inode)->i_pa_cnt--;
781                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
782         }
783 }
784
785 /* Truncate (or enlarge) a file to the requested size. */
786
787 void
788 affs_truncate(struct inode *inode)
789 {
790         struct super_block *sb = inode->i_sb;
791         u32 ext, ext_key;
792         u32 last_blk, blkcnt, blk;
793         u32 size;
794         struct buffer_head *ext_bh;
795         int i;
796
797         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
798                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
799
800         last_blk = 0;
801         ext = 0;
802         if (inode->i_size) {
803                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
804                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
805         }
806
807         if (inode->i_size > AFFS_I(inode)->mmu_private) {
808                 struct address_space *mapping = inode->i_mapping;
809                 struct page *page;
810                 u32 size = inode->i_size - 1;
811                 int res;
812
813                 page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT);
814                 if (!page)
815                         return;
816                 size = (size & (PAGE_CACHE_SIZE - 1)) + 1;
817                 res = mapping->a_ops->prepare_write(NULL, page, size, size);
818                 if (!res)
819                         res = mapping->a_ops->commit_write(NULL, page, size, size);
820                 unlock_page(page);
821                 page_cache_release(page);
822                 mark_inode_dirty(inode);
823                 return;
824         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
825                 return;
826
827         // lock cache
828         ext_bh = affs_get_extblock(inode, ext);
829         if (IS_ERR(ext_bh)) {
830                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
831                              ext, PTR_ERR(ext_bh));
832                 return;
833         }
834         if (AFFS_I(inode)->i_lc) {
835                 /* clear linear cache */
836                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
837                 if (AFFS_I(inode)->i_lc_size > i) {
838                         AFFS_I(inode)->i_lc_size = i;
839                         for (; i < AFFS_LC_SIZE; i++)
840                                 AFFS_I(inode)->i_lc[i] = 0;
841                 }
842                 /* clear associative cache */
843                 for (i = 0; i < AFFS_AC_SIZE; i++)
844                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
845                                 AFFS_I(inode)->i_ac[i].ext = 0;
846         }
847         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
848
849         blkcnt = AFFS_I(inode)->i_blkcnt;
850         i = 0;
851         blk = last_blk;
852         if (inode->i_size) {
853                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
854                 blk++;
855         } else
856                 AFFS_HEAD(ext_bh)->first_data = 0;
857         size = AFFS_SB(sb)->s_hashsize;
858         if (size > blkcnt - blk + i)
859                 size = blkcnt - blk + i;
860         for (; i < size; i++, blk++) {
861                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
862                 AFFS_BLOCK(sb, ext_bh, i) = 0;
863         }
864         AFFS_TAIL(sb, ext_bh)->extension = 0;
865         affs_fix_checksum(sb, ext_bh);
866         mark_buffer_dirty_inode(ext_bh, inode);
867         affs_brelse(ext_bh);
868
869         if (inode->i_size) {
870                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
871                 AFFS_I(inode)->i_extcnt = ext + 1;
872                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
873                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
874                         u32 tmp;
875                         if (IS_ERR(ext_bh)) {
876                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
877                                              ext, PTR_ERR(ext_bh));
878                                 return;
879                         }
880                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
881                         AFFS_DATA_HEAD(bh)->next = 0;
882                         affs_adjust_checksum(bh, -tmp);
883                         affs_brelse(bh);
884                 }
885         } else {
886                 AFFS_I(inode)->i_blkcnt = 0;
887                 AFFS_I(inode)->i_extcnt = 1;
888         }
889         AFFS_I(inode)->mmu_private = inode->i_size;
890         // unlock cache
891
892         while (ext_key) {
893                 ext_bh = affs_bread(sb, ext_key);
894                 size = AFFS_SB(sb)->s_hashsize;
895                 if (size > blkcnt - blk)
896                         size = blkcnt - blk;
897                 for (i = 0; i < size; i++, blk++)
898                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
899                 affs_free_block(sb, ext_key);
900                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
901                 affs_brelse(ext_bh);
902         }
903         affs_free_prealloc(inode);
904 }