fs: affs convert to new aops
[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         .splice_read    = generic_file_splice_read,
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
399 static int affs_readpage(struct file *file, struct page *page)
400 {
401         return block_read_full_page(page, affs_get_block);
402 }
403
404 static int affs_write_begin(struct file *file, struct address_space *mapping,
405                         loff_t pos, unsigned len, unsigned flags,
406                         struct page **pagep, void **fsdata)
407 {
408         *pagep = NULL;
409         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
410                                 affs_get_block,
411                                 &AFFS_I(mapping->host)->mmu_private);
412 }
413
414 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
415 {
416         return generic_block_bmap(mapping,block,affs_get_block);
417 }
418
419 const struct address_space_operations affs_aops = {
420         .readpage = affs_readpage,
421         .writepage = affs_writepage,
422         .sync_page = block_sync_page,
423         .write_begin = affs_write_begin,
424         .write_end = generic_write_end,
425         .bmap = _affs_bmap
426 };
427
428 static inline struct buffer_head *
429 affs_bread_ino(struct inode *inode, int block, int create)
430 {
431         struct buffer_head *bh, tmp_bh;
432         int err;
433
434         tmp_bh.b_state = 0;
435         err = affs_get_block(inode, block, &tmp_bh, create);
436         if (!err) {
437                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
438                 if (bh) {
439                         bh->b_state |= tmp_bh.b_state;
440                         return bh;
441                 }
442                 err = -EIO;
443         }
444         return ERR_PTR(err);
445 }
446
447 static inline struct buffer_head *
448 affs_getzeroblk_ino(struct inode *inode, int block)
449 {
450         struct buffer_head *bh, tmp_bh;
451         int err;
452
453         tmp_bh.b_state = 0;
454         err = affs_get_block(inode, block, &tmp_bh, 1);
455         if (!err) {
456                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
457                 if (bh) {
458                         bh->b_state |= tmp_bh.b_state;
459                         return bh;
460                 }
461                 err = -EIO;
462         }
463         return ERR_PTR(err);
464 }
465
466 static inline struct buffer_head *
467 affs_getemptyblk_ino(struct inode *inode, int block)
468 {
469         struct buffer_head *bh, tmp_bh;
470         int err;
471
472         tmp_bh.b_state = 0;
473         err = affs_get_block(inode, block, &tmp_bh, 1);
474         if (!err) {
475                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
476                 if (bh) {
477                         bh->b_state |= tmp_bh.b_state;
478                         return bh;
479                 }
480                 err = -EIO;
481         }
482         return ERR_PTR(err);
483 }
484
485 static int
486 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
487 {
488         struct inode *inode = page->mapping->host;
489         struct super_block *sb = inode->i_sb;
490         struct buffer_head *bh;
491         char *data;
492         u32 bidx, boff, bsize;
493         u32 tmp;
494
495         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
496         if (from > to || to > PAGE_CACHE_SIZE)
497                 BUG();
498         kmap(page);
499         data = page_address(page);
500         bsize = AFFS_SB(sb)->s_data_blksize;
501         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
502         bidx = tmp / bsize;
503         boff = tmp % bsize;
504
505         while (from < to) {
506                 bh = affs_bread_ino(inode, bidx, 0);
507                 if (IS_ERR(bh))
508                         return PTR_ERR(bh);
509                 tmp = min(bsize - boff, to - from);
510                 if (from + tmp > to || tmp > bsize)
511                         BUG();
512                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
513                 affs_brelse(bh);
514                 bidx++;
515                 from += tmp;
516                 boff = 0;
517         }
518         flush_dcache_page(page);
519         kunmap(page);
520         return 0;
521 }
522
523 static int
524 affs_extent_file_ofs(struct inode *inode, u32 newsize)
525 {
526         struct super_block *sb = inode->i_sb;
527         struct buffer_head *bh, *prev_bh;
528         u32 bidx, boff;
529         u32 size, bsize;
530         u32 tmp;
531
532         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
533         bsize = AFFS_SB(sb)->s_data_blksize;
534         bh = NULL;
535         size = AFFS_I(inode)->mmu_private;
536         bidx = size / bsize;
537         boff = size % bsize;
538         if (boff) {
539                 bh = affs_bread_ino(inode, bidx, 0);
540                 if (IS_ERR(bh))
541                         return PTR_ERR(bh);
542                 tmp = min(bsize - boff, newsize - size);
543                 if (boff + tmp > bsize || tmp > bsize)
544                         BUG();
545                 memset(AFFS_DATA(bh) + boff, 0, tmp);
546                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
547                 affs_fix_checksum(sb, bh);
548                 mark_buffer_dirty_inode(bh, inode);
549                 size += tmp;
550                 bidx++;
551         } else if (bidx) {
552                 bh = affs_bread_ino(inode, bidx - 1, 0);
553                 if (IS_ERR(bh))
554                         return PTR_ERR(bh);
555         }
556
557         while (size < newsize) {
558                 prev_bh = bh;
559                 bh = affs_getzeroblk_ino(inode, bidx);
560                 if (IS_ERR(bh))
561                         goto out;
562                 tmp = min(bsize, newsize - size);
563                 if (tmp > bsize)
564                         BUG();
565                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
566                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
567                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
568                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
569                 affs_fix_checksum(sb, bh);
570                 bh->b_state &= ~(1UL << BH_New);
571                 mark_buffer_dirty_inode(bh, inode);
572                 if (prev_bh) {
573                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
574                         if (tmp)
575                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
576                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
577                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
578                         mark_buffer_dirty_inode(prev_bh, inode);
579                         affs_brelse(prev_bh);
580                 }
581                 size += bsize;
582                 bidx++;
583         }
584         affs_brelse(bh);
585         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
586         return 0;
587
588 out:
589         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
590         return PTR_ERR(bh);
591 }
592
593 static int
594 affs_readpage_ofs(struct file *file, struct page *page)
595 {
596         struct inode *inode = page->mapping->host;
597         u32 to;
598         int err;
599
600         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
601         to = PAGE_CACHE_SIZE;
602         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
603                 to = inode->i_size & ~PAGE_CACHE_MASK;
604                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
605         }
606
607         err = affs_do_readpage_ofs(file, page, 0, to);
608         if (!err)
609                 SetPageUptodate(page);
610         unlock_page(page);
611         return err;
612 }
613
614 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
615                                 loff_t pos, unsigned len, unsigned flags,
616                                 struct page **pagep, void **fsdata)
617 {
618         struct inode *inode = mapping->host;
619         struct page *page;
620         pgoff_t index;
621         int err = 0;
622
623         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
624         if (pos > AFFS_I(inode)->mmu_private) {
625                 /* XXX: this probably leaves a too-big i_size in case of
626                  * failure. Should really be updating i_size at write_end time
627                  */
628                 err = affs_extent_file_ofs(inode, pos);
629                 if (err)
630                         return err;
631         }
632
633         index = pos >> PAGE_CACHE_SHIFT;
634         page = __grab_cache_page(mapping, index);
635         if (!page)
636                 return -ENOMEM;
637         *pagep = page;
638
639         if (PageUptodate(page))
640                 return 0;
641
642         /* XXX: inefficient but safe in the face of short writes */
643         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
644         if (err) {
645                 unlock_page(page);
646                 page_cache_release(page);
647         }
648         return err;
649 }
650
651 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
652                                 loff_t pos, unsigned len, unsigned copied,
653                                 struct page *page, void *fsdata)
654 {
655         struct inode *inode = mapping->host;
656         struct super_block *sb = inode->i_sb;
657         struct buffer_head *bh, *prev_bh;
658         char *data;
659         u32 bidx, boff, bsize;
660         unsigned from, to;
661         u32 tmp;
662         int written;
663
664         from = pos & (PAGE_CACHE_SIZE - 1);
665         to = pos + len;
666         /*
667          * XXX: not sure if this can handle short copies (len < copied), but
668          * we don't have to, because the page should always be uptodate here,
669          * due to write_begin.
670          */
671
672         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
673         bsize = AFFS_SB(sb)->s_data_blksize;
674         data = page_address(page);
675
676         bh = NULL;
677         written = 0;
678         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
679         bidx = tmp / bsize;
680         boff = tmp % bsize;
681         if (boff) {
682                 bh = affs_bread_ino(inode, bidx, 0);
683                 if (IS_ERR(bh))
684                         return PTR_ERR(bh);
685                 tmp = min(bsize - boff, to - from);
686                 if (boff + tmp > bsize || tmp > bsize)
687                         BUG();
688                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
689                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
690                 affs_fix_checksum(sb, bh);
691                 mark_buffer_dirty_inode(bh, inode);
692                 written += tmp;
693                 from += tmp;
694                 bidx++;
695         } else if (bidx) {
696                 bh = affs_bread_ino(inode, bidx - 1, 0);
697                 if (IS_ERR(bh))
698                         return PTR_ERR(bh);
699         }
700         while (from + bsize <= to) {
701                 prev_bh = bh;
702                 bh = affs_getemptyblk_ino(inode, bidx);
703                 if (IS_ERR(bh))
704                         goto out;
705                 memcpy(AFFS_DATA(bh), data + from, bsize);
706                 if (buffer_new(bh)) {
707                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
708                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
709                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
710                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
711                         AFFS_DATA_HEAD(bh)->next = 0;
712                         bh->b_state &= ~(1UL << BH_New);
713                         if (prev_bh) {
714                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
715                                 if (tmp)
716                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
717                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
718                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
719                                 mark_buffer_dirty_inode(prev_bh, inode);
720                         }
721                 }
722                 affs_brelse(prev_bh);
723                 affs_fix_checksum(sb, bh);
724                 mark_buffer_dirty_inode(bh, inode);
725                 written += bsize;
726                 from += bsize;
727                 bidx++;
728         }
729         if (from < to) {
730                 prev_bh = bh;
731                 bh = affs_bread_ino(inode, bidx, 1);
732                 if (IS_ERR(bh))
733                         goto out;
734                 tmp = min(bsize, to - from);
735                 if (tmp > bsize)
736                         BUG();
737                 memcpy(AFFS_DATA(bh), data + from, tmp);
738                 if (buffer_new(bh)) {
739                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
740                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
741                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
742                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
743                         AFFS_DATA_HEAD(bh)->next = 0;
744                         bh->b_state &= ~(1UL << BH_New);
745                         if (prev_bh) {
746                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
747                                 if (tmp)
748                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
749                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
750                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
751                                 mark_buffer_dirty_inode(prev_bh, inode);
752                         }
753                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
754                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
755                 affs_brelse(prev_bh);
756                 affs_fix_checksum(sb, bh);
757                 mark_buffer_dirty_inode(bh, inode);
758                 written += tmp;
759                 from += tmp;
760                 bidx++;
761         }
762         SetPageUptodate(page);
763
764 done:
765         affs_brelse(bh);
766         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
767         if (tmp > inode->i_size)
768                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
769
770         unlock_page(page);
771         page_cache_release(page);
772
773         return written;
774
775 out:
776         bh = prev_bh;
777         if (!written)
778                 written = PTR_ERR(bh);
779         goto done;
780 }
781
782 const struct address_space_operations affs_aops_ofs = {
783         .readpage = affs_readpage_ofs,
784         //.writepage = affs_writepage_ofs,
785         //.sync_page = affs_sync_page_ofs,
786         .write_begin = affs_write_begin_ofs,
787         .write_end = affs_write_end_ofs
788 };
789
790 /* Free any preallocated blocks. */
791
792 void
793 affs_free_prealloc(struct inode *inode)
794 {
795         struct super_block *sb = inode->i_sb;
796
797         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
798
799         while (AFFS_I(inode)->i_pa_cnt) {
800                 AFFS_I(inode)->i_pa_cnt--;
801                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
802         }
803 }
804
805 /* Truncate (or enlarge) a file to the requested size. */
806
807 void
808 affs_truncate(struct inode *inode)
809 {
810         struct super_block *sb = inode->i_sb;
811         u32 ext, ext_key;
812         u32 last_blk, blkcnt, blk;
813         u32 size;
814         struct buffer_head *ext_bh;
815         int i;
816
817         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
818                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
819
820         last_blk = 0;
821         ext = 0;
822         if (inode->i_size) {
823                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
824                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
825         }
826
827         if (inode->i_size > AFFS_I(inode)->mmu_private) {
828                 struct address_space *mapping = inode->i_mapping;
829                 struct page *page;
830                 void *fsdata;
831                 u32 size = inode->i_size;
832                 int res;
833
834                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
835                 if (!res)
836                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
837                 mark_inode_dirty(inode);
838                 return;
839         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
840                 return;
841
842         // lock cache
843         ext_bh = affs_get_extblock(inode, ext);
844         if (IS_ERR(ext_bh)) {
845                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
846                              ext, PTR_ERR(ext_bh));
847                 return;
848         }
849         if (AFFS_I(inode)->i_lc) {
850                 /* clear linear cache */
851                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
852                 if (AFFS_I(inode)->i_lc_size > i) {
853                         AFFS_I(inode)->i_lc_size = i;
854                         for (; i < AFFS_LC_SIZE; i++)
855                                 AFFS_I(inode)->i_lc[i] = 0;
856                 }
857                 /* clear associative cache */
858                 for (i = 0; i < AFFS_AC_SIZE; i++)
859                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
860                                 AFFS_I(inode)->i_ac[i].ext = 0;
861         }
862         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
863
864         blkcnt = AFFS_I(inode)->i_blkcnt;
865         i = 0;
866         blk = last_blk;
867         if (inode->i_size) {
868                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
869                 blk++;
870         } else
871                 AFFS_HEAD(ext_bh)->first_data = 0;
872         size = AFFS_SB(sb)->s_hashsize;
873         if (size > blkcnt - blk + i)
874                 size = blkcnt - blk + i;
875         for (; i < size; i++, blk++) {
876                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
877                 AFFS_BLOCK(sb, ext_bh, i) = 0;
878         }
879         AFFS_TAIL(sb, ext_bh)->extension = 0;
880         affs_fix_checksum(sb, ext_bh);
881         mark_buffer_dirty_inode(ext_bh, inode);
882         affs_brelse(ext_bh);
883
884         if (inode->i_size) {
885                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
886                 AFFS_I(inode)->i_extcnt = ext + 1;
887                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
888                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
889                         u32 tmp;
890                         if (IS_ERR(ext_bh)) {
891                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
892                                              ext, PTR_ERR(ext_bh));
893                                 return;
894                         }
895                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
896                         AFFS_DATA_HEAD(bh)->next = 0;
897                         affs_adjust_checksum(bh, -tmp);
898                         affs_brelse(bh);
899                 }
900         } else {
901                 AFFS_I(inode)->i_blkcnt = 0;
902                 AFFS_I(inode)->i_extcnt = 1;
903         }
904         AFFS_I(inode)->mmu_private = inode->i_size;
905         // unlock cache
906
907         while (ext_key) {
908                 ext_bh = affs_bread(sb, ext_key);
909                 size = AFFS_SB(sb)->s_hashsize;
910                 if (size > blkcnt - blk)
911                         size = blkcnt - blk;
912                 for (i = 0; i < size; i++, blk++)
913                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
914                 affs_free_block(sb, ext_key);
915                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
916                 affs_brelse(ext_bh);
917         }
918         affs_free_prealloc(inode);
919 }