nilfs2: remove double bio_put() in nilfs_end_bio_write() for BIO_EOPNOTSUPP error
[linux-3.10.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          = affs_file_fsync,
38         .splice_read    = generic_file_splice_read,
39 };
40
41 const struct inode_operations affs_file_inode_operations = {
42         .setattr        = affs_notify_change,
43 };
44
45 static int
46 affs_file_open(struct inode *inode, struct file *filp)
47 {
48         pr_debug("AFFS: open(%lu,%d)\n",
49                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
50         atomic_inc(&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         pr_debug("AFFS: release(%lu, %d)\n",
58                  inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
59
60         if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
61                 mutex_lock(&inode->i_mutex);
62                 if (inode->i_size != AFFS_I(inode)->mmu_private)
63                         affs_truncate(inode);
64                 affs_free_prealloc(inode);
65                 mutex_unlock(&inode->i_mutex);
66         }
67
68         return 0;
69 }
70
71 static int
72 affs_grow_extcache(struct inode *inode, u32 lc_idx)
73 {
74         struct super_block      *sb = inode->i_sb;
75         struct buffer_head      *bh;
76         u32 lc_max;
77         int i, j, key;
78
79         if (!AFFS_I(inode)->i_lc) {
80                 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
81                 if (!ptr)
82                         return -ENOMEM;
83                 AFFS_I(inode)->i_lc = (u32 *)ptr;
84                 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
85         }
86
87         lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
88
89         if (AFFS_I(inode)->i_extcnt > lc_max) {
90                 u32 lc_shift, lc_mask, tmp, off;
91
92                 /* need to recalculate linear cache, start from old size */
93                 lc_shift = AFFS_I(inode)->i_lc_shift;
94                 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
95                 for (; tmp; tmp >>= 1)
96                         lc_shift++;
97                 lc_mask = (1 << lc_shift) - 1;
98
99                 /* fix idx and old size to new shift */
100                 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
101                 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
102
103                 /* first shrink old cache to make more space */
104                 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
105                 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
106                         AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
107
108                 AFFS_I(inode)->i_lc_shift = lc_shift;
109                 AFFS_I(inode)->i_lc_mask = lc_mask;
110         }
111
112         /* fill cache to the needed index */
113         i = AFFS_I(inode)->i_lc_size;
114         AFFS_I(inode)->i_lc_size = lc_idx + 1;
115         for (; i <= lc_idx; i++) {
116                 if (!i) {
117                         AFFS_I(inode)->i_lc[0] = inode->i_ino;
118                         continue;
119                 }
120                 key = AFFS_I(inode)->i_lc[i - 1];
121                 j = AFFS_I(inode)->i_lc_mask + 1;
122                 // unlock cache
123                 for (; j > 0; j--) {
124                         bh = affs_bread(sb, key);
125                         if (!bh)
126                                 goto err;
127                         key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
128                         affs_brelse(bh);
129                 }
130                 // lock cache
131                 AFFS_I(inode)->i_lc[i] = key;
132         }
133
134         return 0;
135
136 err:
137         // lock cache
138         return -EIO;
139 }
140
141 static struct buffer_head *
142 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
143 {
144         struct super_block *sb = inode->i_sb;
145         struct buffer_head *new_bh;
146         u32 blocknr, tmp;
147
148         blocknr = affs_alloc_block(inode, bh->b_blocknr);
149         if (!blocknr)
150                 return ERR_PTR(-ENOSPC);
151
152         new_bh = affs_getzeroblk(sb, blocknr);
153         if (!new_bh) {
154                 affs_free_block(sb, blocknr);
155                 return ERR_PTR(-EIO);
156         }
157
158         AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
159         AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
160         AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
161         AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
162         affs_fix_checksum(sb, new_bh);
163
164         mark_buffer_dirty_inode(new_bh, inode);
165
166         tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
167         if (tmp)
168                 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
169         AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
170         affs_adjust_checksum(bh, blocknr - tmp);
171         mark_buffer_dirty_inode(bh, inode);
172
173         AFFS_I(inode)->i_extcnt++;
174         mark_inode_dirty(inode);
175
176         return new_bh;
177 }
178
179 static inline struct buffer_head *
180 affs_get_extblock(struct inode *inode, u32 ext)
181 {
182         /* inline the simplest case: same extended block as last time */
183         struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
184         if (ext == AFFS_I(inode)->i_ext_last)
185                 get_bh(bh);
186         else
187                 /* we have to do more (not inlined) */
188                 bh = affs_get_extblock_slow(inode, ext);
189
190         return bh;
191 }
192
193 static struct buffer_head *
194 affs_get_extblock_slow(struct inode *inode, u32 ext)
195 {
196         struct super_block *sb = inode->i_sb;
197         struct buffer_head *bh;
198         u32 ext_key;
199         u32 lc_idx, lc_off, ac_idx;
200         u32 tmp, idx;
201
202         if (ext == AFFS_I(inode)->i_ext_last + 1) {
203                 /* read the next extended block from the current one */
204                 bh = AFFS_I(inode)->i_ext_bh;
205                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
206                 if (ext < AFFS_I(inode)->i_extcnt)
207                         goto read_ext;
208                 if (ext > AFFS_I(inode)->i_extcnt)
209                         BUG();
210                 bh = affs_alloc_extblock(inode, bh, ext);
211                 if (IS_ERR(bh))
212                         return bh;
213                 goto store_ext;
214         }
215
216         if (ext == 0) {
217                 /* we seek back to the file header block */
218                 ext_key = inode->i_ino;
219                 goto read_ext;
220         }
221
222         if (ext >= AFFS_I(inode)->i_extcnt) {
223                 struct buffer_head *prev_bh;
224
225                 /* allocate a new extended block */
226                 if (ext > AFFS_I(inode)->i_extcnt)
227                         BUG();
228
229                 /* get previous extended block */
230                 prev_bh = affs_get_extblock(inode, ext - 1);
231                 if (IS_ERR(prev_bh))
232                         return prev_bh;
233                 bh = affs_alloc_extblock(inode, prev_bh, ext);
234                 affs_brelse(prev_bh);
235                 if (IS_ERR(bh))
236                         return bh;
237                 goto store_ext;
238         }
239
240 again:
241         /* check if there is an extended cache and whether it's large enough */
242         lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
243         lc_off = ext & AFFS_I(inode)->i_lc_mask;
244
245         if (lc_idx >= AFFS_I(inode)->i_lc_size) {
246                 int err;
247
248                 err = affs_grow_extcache(inode, lc_idx);
249                 if (err)
250                         return ERR_PTR(err);
251                 goto again;
252         }
253
254         /* every n'th key we find in the linear cache */
255         if (!lc_off) {
256                 ext_key = AFFS_I(inode)->i_lc[lc_idx];
257                 goto read_ext;
258         }
259
260         /* maybe it's still in the associative cache */
261         ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
262         if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
263                 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
264                 goto read_ext;
265         }
266
267         /* try to find one of the previous extended blocks */
268         tmp = ext;
269         idx = ac_idx;
270         while (--tmp, --lc_off > 0) {
271                 idx = (idx - 1) & AFFS_AC_MASK;
272                 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
273                         ext_key = AFFS_I(inode)->i_ac[idx].key;
274                         goto find_ext;
275                 }
276         }
277
278         /* fall back to the linear cache */
279         ext_key = AFFS_I(inode)->i_lc[lc_idx];
280 find_ext:
281         /* read all extended blocks until we find the one we need */
282         //unlock cache
283         do {
284                 bh = affs_bread(sb, ext_key);
285                 if (!bh)
286                         goto err_bread;
287                 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
288                 affs_brelse(bh);
289                 tmp++;
290         } while (tmp < ext);
291         //lock cache
292
293         /* store it in the associative cache */
294         // recalculate ac_idx?
295         AFFS_I(inode)->i_ac[ac_idx].ext = ext;
296         AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
297
298 read_ext:
299         /* finally read the right extended block */
300         //unlock cache
301         bh = affs_bread(sb, ext_key);
302         if (!bh)
303                 goto err_bread;
304         //lock cache
305
306 store_ext:
307         /* release old cached extended block and store the new one */
308         affs_brelse(AFFS_I(inode)->i_ext_bh);
309         AFFS_I(inode)->i_ext_last = ext;
310         AFFS_I(inode)->i_ext_bh = bh;
311         get_bh(bh);
312
313         return bh;
314
315 err_bread:
316         affs_brelse(bh);
317         return ERR_PTR(-EIO);
318 }
319
320 static int
321 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
322 {
323         struct super_block      *sb = inode->i_sb;
324         struct buffer_head      *ext_bh;
325         u32                      ext;
326
327         pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
328
329         BUG_ON(block > (sector_t)0x7fffffffUL);
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 void affs_write_failed(struct address_space *mapping, loff_t to)
405 {
406         struct inode *inode = mapping->host;
407
408         if (to > inode->i_size) {
409                 truncate_pagecache(inode, to, inode->i_size);
410                 affs_truncate(inode);
411         }
412 }
413
414 static int affs_write_begin(struct file *file, struct address_space *mapping,
415                         loff_t pos, unsigned len, unsigned flags,
416                         struct page **pagep, void **fsdata)
417 {
418         int ret;
419
420         *pagep = NULL;
421         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
422                                 affs_get_block,
423                                 &AFFS_I(mapping->host)->mmu_private);
424         if (unlikely(ret))
425                 affs_write_failed(mapping, pos + len);
426
427         return ret;
428 }
429
430 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
431 {
432         return generic_block_bmap(mapping,block,affs_get_block);
433 }
434
435 const struct address_space_operations affs_aops = {
436         .readpage = affs_readpage,
437         .writepage = affs_writepage,
438         .write_begin = affs_write_begin,
439         .write_end = generic_write_end,
440         .bmap = _affs_bmap
441 };
442
443 static inline struct buffer_head *
444 affs_bread_ino(struct inode *inode, int block, int create)
445 {
446         struct buffer_head *bh, tmp_bh;
447         int err;
448
449         tmp_bh.b_state = 0;
450         err = affs_get_block(inode, block, &tmp_bh, create);
451         if (!err) {
452                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
453                 if (bh) {
454                         bh->b_state |= tmp_bh.b_state;
455                         return bh;
456                 }
457                 err = -EIO;
458         }
459         return ERR_PTR(err);
460 }
461
462 static inline struct buffer_head *
463 affs_getzeroblk_ino(struct inode *inode, int block)
464 {
465         struct buffer_head *bh, tmp_bh;
466         int err;
467
468         tmp_bh.b_state = 0;
469         err = affs_get_block(inode, block, &tmp_bh, 1);
470         if (!err) {
471                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
472                 if (bh) {
473                         bh->b_state |= tmp_bh.b_state;
474                         return bh;
475                 }
476                 err = -EIO;
477         }
478         return ERR_PTR(err);
479 }
480
481 static inline struct buffer_head *
482 affs_getemptyblk_ino(struct inode *inode, int block)
483 {
484         struct buffer_head *bh, tmp_bh;
485         int err;
486
487         tmp_bh.b_state = 0;
488         err = affs_get_block(inode, block, &tmp_bh, 1);
489         if (!err) {
490                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
491                 if (bh) {
492                         bh->b_state |= tmp_bh.b_state;
493                         return bh;
494                 }
495                 err = -EIO;
496         }
497         return ERR_PTR(err);
498 }
499
500 static int
501 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
502 {
503         struct inode *inode = page->mapping->host;
504         struct super_block *sb = inode->i_sb;
505         struct buffer_head *bh;
506         char *data;
507         u32 bidx, boff, bsize;
508         u32 tmp;
509
510         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
511         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
512         kmap(page);
513         data = page_address(page);
514         bsize = AFFS_SB(sb)->s_data_blksize;
515         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
516         bidx = tmp / bsize;
517         boff = tmp % bsize;
518
519         while (from < to) {
520                 bh = affs_bread_ino(inode, bidx, 0);
521                 if (IS_ERR(bh))
522                         return PTR_ERR(bh);
523                 tmp = min(bsize - boff, to - from);
524                 BUG_ON(from + tmp > to || tmp > bsize);
525                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
526                 affs_brelse(bh);
527                 bidx++;
528                 from += tmp;
529                 boff = 0;
530         }
531         flush_dcache_page(page);
532         kunmap(page);
533         return 0;
534 }
535
536 static int
537 affs_extent_file_ofs(struct inode *inode, u32 newsize)
538 {
539         struct super_block *sb = inode->i_sb;
540         struct buffer_head *bh, *prev_bh;
541         u32 bidx, boff;
542         u32 size, bsize;
543         u32 tmp;
544
545         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
546         bsize = AFFS_SB(sb)->s_data_blksize;
547         bh = NULL;
548         size = AFFS_I(inode)->mmu_private;
549         bidx = size / bsize;
550         boff = size % bsize;
551         if (boff) {
552                 bh = affs_bread_ino(inode, bidx, 0);
553                 if (IS_ERR(bh))
554                         return PTR_ERR(bh);
555                 tmp = min(bsize - boff, newsize - size);
556                 BUG_ON(boff + tmp > bsize || tmp > bsize);
557                 memset(AFFS_DATA(bh) + boff, 0, tmp);
558                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
559                 affs_fix_checksum(sb, bh);
560                 mark_buffer_dirty_inode(bh, inode);
561                 size += tmp;
562                 bidx++;
563         } else if (bidx) {
564                 bh = affs_bread_ino(inode, bidx - 1, 0);
565                 if (IS_ERR(bh))
566                         return PTR_ERR(bh);
567         }
568
569         while (size < newsize) {
570                 prev_bh = bh;
571                 bh = affs_getzeroblk_ino(inode, bidx);
572                 if (IS_ERR(bh))
573                         goto out;
574                 tmp = min(bsize, newsize - size);
575                 BUG_ON(tmp > bsize);
576                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
577                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
578                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
579                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
580                 affs_fix_checksum(sb, bh);
581                 bh->b_state &= ~(1UL << BH_New);
582                 mark_buffer_dirty_inode(bh, inode);
583                 if (prev_bh) {
584                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
585                         if (tmp)
586                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
587                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
588                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
589                         mark_buffer_dirty_inode(prev_bh, inode);
590                         affs_brelse(prev_bh);
591                 }
592                 size += bsize;
593                 bidx++;
594         }
595         affs_brelse(bh);
596         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
597         return 0;
598
599 out:
600         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
601         return PTR_ERR(bh);
602 }
603
604 static int
605 affs_readpage_ofs(struct file *file, struct page *page)
606 {
607         struct inode *inode = page->mapping->host;
608         u32 to;
609         int err;
610
611         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
612         to = PAGE_CACHE_SIZE;
613         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
614                 to = inode->i_size & ~PAGE_CACHE_MASK;
615                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
616         }
617
618         err = affs_do_readpage_ofs(file, page, 0, to);
619         if (!err)
620                 SetPageUptodate(page);
621         unlock_page(page);
622         return err;
623 }
624
625 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
626                                 loff_t pos, unsigned len, unsigned flags,
627                                 struct page **pagep, void **fsdata)
628 {
629         struct inode *inode = mapping->host;
630         struct page *page;
631         pgoff_t index;
632         int err = 0;
633
634         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
635         if (pos > AFFS_I(inode)->mmu_private) {
636                 /* XXX: this probably leaves a too-big i_size in case of
637                  * failure. Should really be updating i_size at write_end time
638                  */
639                 err = affs_extent_file_ofs(inode, pos);
640                 if (err)
641                         return err;
642         }
643
644         index = pos >> PAGE_CACHE_SHIFT;
645         page = grab_cache_page_write_begin(mapping, index, flags);
646         if (!page)
647                 return -ENOMEM;
648         *pagep = page;
649
650         if (PageUptodate(page))
651                 return 0;
652
653         /* XXX: inefficient but safe in the face of short writes */
654         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
655         if (err) {
656                 unlock_page(page);
657                 page_cache_release(page);
658         }
659         return err;
660 }
661
662 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
663                                 loff_t pos, unsigned len, unsigned copied,
664                                 struct page *page, void *fsdata)
665 {
666         struct inode *inode = mapping->host;
667         struct super_block *sb = inode->i_sb;
668         struct buffer_head *bh, *prev_bh;
669         char *data;
670         u32 bidx, boff, bsize;
671         unsigned from, to;
672         u32 tmp;
673         int written;
674
675         from = pos & (PAGE_CACHE_SIZE - 1);
676         to = pos + len;
677         /*
678          * XXX: not sure if this can handle short copies (len < copied), but
679          * we don't have to, because the page should always be uptodate here,
680          * due to write_begin.
681          */
682
683         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
684         bsize = AFFS_SB(sb)->s_data_blksize;
685         data = page_address(page);
686
687         bh = NULL;
688         written = 0;
689         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
690         bidx = tmp / bsize;
691         boff = tmp % bsize;
692         if (boff) {
693                 bh = affs_bread_ino(inode, bidx, 0);
694                 if (IS_ERR(bh))
695                         return PTR_ERR(bh);
696                 tmp = min(bsize - boff, to - from);
697                 BUG_ON(boff + tmp > bsize || tmp > bsize);
698                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
699                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
700                 affs_fix_checksum(sb, bh);
701                 mark_buffer_dirty_inode(bh, inode);
702                 written += tmp;
703                 from += tmp;
704                 bidx++;
705         } else if (bidx) {
706                 bh = affs_bread_ino(inode, bidx - 1, 0);
707                 if (IS_ERR(bh))
708                         return PTR_ERR(bh);
709         }
710         while (from + bsize <= to) {
711                 prev_bh = bh;
712                 bh = affs_getemptyblk_ino(inode, bidx);
713                 if (IS_ERR(bh))
714                         goto out;
715                 memcpy(AFFS_DATA(bh), data + from, bsize);
716                 if (buffer_new(bh)) {
717                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
718                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
719                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
720                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
721                         AFFS_DATA_HEAD(bh)->next = 0;
722                         bh->b_state &= ~(1UL << BH_New);
723                         if (prev_bh) {
724                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
725                                 if (tmp)
726                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
727                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
728                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
729                                 mark_buffer_dirty_inode(prev_bh, inode);
730                         }
731                 }
732                 affs_brelse(prev_bh);
733                 affs_fix_checksum(sb, bh);
734                 mark_buffer_dirty_inode(bh, inode);
735                 written += bsize;
736                 from += bsize;
737                 bidx++;
738         }
739         if (from < to) {
740                 prev_bh = bh;
741                 bh = affs_bread_ino(inode, bidx, 1);
742                 if (IS_ERR(bh))
743                         goto out;
744                 tmp = min(bsize, to - from);
745                 BUG_ON(tmp > bsize);
746                 memcpy(AFFS_DATA(bh), data + from, tmp);
747                 if (buffer_new(bh)) {
748                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
749                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
750                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
751                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
752                         AFFS_DATA_HEAD(bh)->next = 0;
753                         bh->b_state &= ~(1UL << BH_New);
754                         if (prev_bh) {
755                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
756                                 if (tmp)
757                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
758                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
759                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
760                                 mark_buffer_dirty_inode(prev_bh, inode);
761                         }
762                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
763                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
764                 affs_brelse(prev_bh);
765                 affs_fix_checksum(sb, bh);
766                 mark_buffer_dirty_inode(bh, inode);
767                 written += tmp;
768                 from += tmp;
769                 bidx++;
770         }
771         SetPageUptodate(page);
772
773 done:
774         affs_brelse(bh);
775         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
776         if (tmp > inode->i_size)
777                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
778
779         unlock_page(page);
780         page_cache_release(page);
781
782         return written;
783
784 out:
785         bh = prev_bh;
786         if (!written)
787                 written = PTR_ERR(bh);
788         goto done;
789 }
790
791 const struct address_space_operations affs_aops_ofs = {
792         .readpage = affs_readpage_ofs,
793         //.writepage = affs_writepage_ofs,
794         .write_begin = affs_write_begin_ofs,
795         .write_end = affs_write_end_ofs
796 };
797
798 /* Free any preallocated blocks. */
799
800 void
801 affs_free_prealloc(struct inode *inode)
802 {
803         struct super_block *sb = inode->i_sb;
804
805         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
806
807         while (AFFS_I(inode)->i_pa_cnt) {
808                 AFFS_I(inode)->i_pa_cnt--;
809                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
810         }
811 }
812
813 /* Truncate (or enlarge) a file to the requested size. */
814
815 void
816 affs_truncate(struct inode *inode)
817 {
818         struct super_block *sb = inode->i_sb;
819         u32 ext, ext_key;
820         u32 last_blk, blkcnt, blk;
821         u32 size;
822         struct buffer_head *ext_bh;
823         int i;
824
825         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
826                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
827
828         last_blk = 0;
829         ext = 0;
830         if (inode->i_size) {
831                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
832                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
833         }
834
835         if (inode->i_size > AFFS_I(inode)->mmu_private) {
836                 struct address_space *mapping = inode->i_mapping;
837                 struct page *page;
838                 void *fsdata;
839                 u32 size = inode->i_size;
840                 int res;
841
842                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
843                 if (!res)
844                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
845                 else
846                         inode->i_size = AFFS_I(inode)->mmu_private;
847                 mark_inode_dirty(inode);
848                 return;
849         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
850                 return;
851
852         // lock cache
853         ext_bh = affs_get_extblock(inode, ext);
854         if (IS_ERR(ext_bh)) {
855                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
856                              ext, PTR_ERR(ext_bh));
857                 return;
858         }
859         if (AFFS_I(inode)->i_lc) {
860                 /* clear linear cache */
861                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
862                 if (AFFS_I(inode)->i_lc_size > i) {
863                         AFFS_I(inode)->i_lc_size = i;
864                         for (; i < AFFS_LC_SIZE; i++)
865                                 AFFS_I(inode)->i_lc[i] = 0;
866                 }
867                 /* clear associative cache */
868                 for (i = 0; i < AFFS_AC_SIZE; i++)
869                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
870                                 AFFS_I(inode)->i_ac[i].ext = 0;
871         }
872         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
873
874         blkcnt = AFFS_I(inode)->i_blkcnt;
875         i = 0;
876         blk = last_blk;
877         if (inode->i_size) {
878                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
879                 blk++;
880         } else
881                 AFFS_HEAD(ext_bh)->first_data = 0;
882         AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
883         size = AFFS_SB(sb)->s_hashsize;
884         if (size > blkcnt - blk + i)
885                 size = blkcnt - blk + i;
886         for (; i < size; i++, blk++) {
887                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
888                 AFFS_BLOCK(sb, ext_bh, i) = 0;
889         }
890         AFFS_TAIL(sb, ext_bh)->extension = 0;
891         affs_fix_checksum(sb, ext_bh);
892         mark_buffer_dirty_inode(ext_bh, inode);
893         affs_brelse(ext_bh);
894
895         if (inode->i_size) {
896                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
897                 AFFS_I(inode)->i_extcnt = ext + 1;
898                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
899                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
900                         u32 tmp;
901                         if (IS_ERR(bh)) {
902                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
903                                              ext, PTR_ERR(bh));
904                                 return;
905                         }
906                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
907                         AFFS_DATA_HEAD(bh)->next = 0;
908                         affs_adjust_checksum(bh, -tmp);
909                         affs_brelse(bh);
910                 }
911         } else {
912                 AFFS_I(inode)->i_blkcnt = 0;
913                 AFFS_I(inode)->i_extcnt = 1;
914         }
915         AFFS_I(inode)->mmu_private = inode->i_size;
916         // unlock cache
917
918         while (ext_key) {
919                 ext_bh = affs_bread(sb, ext_key);
920                 size = AFFS_SB(sb)->s_hashsize;
921                 if (size > blkcnt - blk)
922                         size = blkcnt - blk;
923                 for (i = 0; i < size; i++, blk++)
924                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
925                 affs_free_block(sb, ext_key);
926                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
927                 affs_brelse(ext_bh);
928         }
929         affs_free_prealloc(inode);
930 }
931
932 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
933 {
934         struct inode *inode = filp->f_mapping->host;
935         int ret, err;
936
937         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
938         if (err)
939                 return err;
940
941         mutex_lock(&inode->i_mutex);
942         ret = write_inode_now(inode, 0);
943         err = sync_blockdev(inode->i_sb->s_bdev);
944         if (!ret)
945                 ret = err;
946         mutex_unlock(&inode->i_mutex);
947         return ret;
948 }