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