Merge branch 'for-2.6.26' of master.kernel.org:/pub/scm/linux/kernel/git/jwboyer...
[linux-2.6] / fs / affs / file.c
1 /*
2  *  linux/fs/affs/file.c
3  *
4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
5  *
6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
7  *
8  *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
9  *
10  *  (C) 1991  Linus Torvalds - minix filesystem
11  *
12  *  affs regular file handling primitives
13  */
14
15 #include "affs.h"
16
17 #if PAGE_SIZE < 4096
18 #error PAGE_SIZE must be at least 4096
19 #endif
20
21 static int affs_grow_extcache(struct inode *inode, u32 lc_idx);
22 static struct buffer_head *affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext);
23 static inline struct buffer_head *affs_get_extblock(struct inode *inode, u32 ext);
24 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
25 static int affs_file_open(struct inode *inode, struct file *filp);
26 static int affs_file_release(struct inode *inode, struct file *filp);
27
28 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         BUG_ON(block > (sector_t)0x7fffffffUL);
329
330         if (block >= AFFS_I(inode)->i_blkcnt) {
331                 if (block > AFFS_I(inode)->i_blkcnt || !create)
332                         goto err_big;
333         } else
334                 create = 0;
335
336         //lock cache
337         affs_lock_ext(inode);
338
339         ext = (u32)block / AFFS_SB(sb)->s_hashsize;
340         block -= ext * AFFS_SB(sb)->s_hashsize;
341         ext_bh = affs_get_extblock(inode, ext);
342         if (IS_ERR(ext_bh))
343                 goto err_ext;
344         map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
345
346         if (create) {
347                 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
348                 if (!blocknr)
349                         goto err_alloc;
350                 set_buffer_new(bh_result);
351                 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
352                 AFFS_I(inode)->i_blkcnt++;
353
354                 /* store new block */
355                 if (bh_result->b_blocknr)
356                         affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
357                 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
358                 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
359                 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
360                 bh_result->b_blocknr = blocknr;
361
362                 if (!block) {
363                         /* insert first block into header block */
364                         u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
365                         if (tmp)
366                                 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
367                         AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
368                         affs_adjust_checksum(ext_bh, blocknr - tmp);
369                 }
370         }
371
372         affs_brelse(ext_bh);
373         //unlock cache
374         affs_unlock_ext(inode);
375         return 0;
376
377 err_big:
378         affs_error(inode->i_sb,"get_block","strange block request %d", block);
379         return -EIO;
380 err_ext:
381         // unlock cache
382         affs_unlock_ext(inode);
383         return PTR_ERR(ext_bh);
384 err_alloc:
385         brelse(ext_bh);
386         clear_buffer_mapped(bh_result);
387         bh_result->b_bdev = NULL;
388         // unlock cache
389         affs_unlock_ext(inode);
390         return -ENOSPC;
391 }
392
393 static int affs_writepage(struct page *page, struct writeback_control *wbc)
394 {
395         return block_write_full_page(page, affs_get_block, wbc);
396 }
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
403 static int affs_write_begin(struct file *file, struct address_space *mapping,
404                         loff_t pos, unsigned len, unsigned flags,
405                         struct page **pagep, void **fsdata)
406 {
407         *pagep = NULL;
408         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
409                                 affs_get_block,
410                                 &AFFS_I(mapping->host)->mmu_private);
411 }
412
413 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
414 {
415         return generic_block_bmap(mapping,block,affs_get_block);
416 }
417
418 const struct address_space_operations affs_aops = {
419         .readpage = affs_readpage,
420         .writepage = affs_writepage,
421         .sync_page = block_sync_page,
422         .write_begin = affs_write_begin,
423         .write_end = generic_write_end,
424         .bmap = _affs_bmap
425 };
426
427 static inline struct buffer_head *
428 affs_bread_ino(struct inode *inode, int block, int create)
429 {
430         struct buffer_head *bh, tmp_bh;
431         int err;
432
433         tmp_bh.b_state = 0;
434         err = affs_get_block(inode, block, &tmp_bh, create);
435         if (!err) {
436                 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
437                 if (bh) {
438                         bh->b_state |= tmp_bh.b_state;
439                         return bh;
440                 }
441                 err = -EIO;
442         }
443         return ERR_PTR(err);
444 }
445
446 static inline struct buffer_head *
447 affs_getzeroblk_ino(struct inode *inode, int block)
448 {
449         struct buffer_head *bh, tmp_bh;
450         int err;
451
452         tmp_bh.b_state = 0;
453         err = affs_get_block(inode, block, &tmp_bh, 1);
454         if (!err) {
455                 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
456                 if (bh) {
457                         bh->b_state |= tmp_bh.b_state;
458                         return bh;
459                 }
460                 err = -EIO;
461         }
462         return ERR_PTR(err);
463 }
464
465 static inline struct buffer_head *
466 affs_getemptyblk_ino(struct inode *inode, int block)
467 {
468         struct buffer_head *bh, tmp_bh;
469         int err;
470
471         tmp_bh.b_state = 0;
472         err = affs_get_block(inode, block, &tmp_bh, 1);
473         if (!err) {
474                 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
475                 if (bh) {
476                         bh->b_state |= tmp_bh.b_state;
477                         return bh;
478                 }
479                 err = -EIO;
480         }
481         return ERR_PTR(err);
482 }
483
484 static int
485 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
486 {
487         struct inode *inode = page->mapping->host;
488         struct super_block *sb = inode->i_sb;
489         struct buffer_head *bh;
490         char *data;
491         u32 bidx, boff, bsize;
492         u32 tmp;
493
494         pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
495         BUG_ON(from > to || to > PAGE_CACHE_SIZE);
496         kmap(page);
497         data = page_address(page);
498         bsize = AFFS_SB(sb)->s_data_blksize;
499         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
500         bidx = tmp / bsize;
501         boff = tmp % bsize;
502
503         while (from < to) {
504                 bh = affs_bread_ino(inode, bidx, 0);
505                 if (IS_ERR(bh))
506                         return PTR_ERR(bh);
507                 tmp = min(bsize - boff, to - from);
508                 BUG_ON(from + tmp > to || tmp > bsize);
509                 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
510                 affs_brelse(bh);
511                 bidx++;
512                 from += tmp;
513                 boff = 0;
514         }
515         flush_dcache_page(page);
516         kunmap(page);
517         return 0;
518 }
519
520 static int
521 affs_extent_file_ofs(struct inode *inode, u32 newsize)
522 {
523         struct super_block *sb = inode->i_sb;
524         struct buffer_head *bh, *prev_bh;
525         u32 bidx, boff;
526         u32 size, bsize;
527         u32 tmp;
528
529         pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
530         bsize = AFFS_SB(sb)->s_data_blksize;
531         bh = NULL;
532         size = AFFS_I(inode)->mmu_private;
533         bidx = size / bsize;
534         boff = size % bsize;
535         if (boff) {
536                 bh = affs_bread_ino(inode, bidx, 0);
537                 if (IS_ERR(bh))
538                         return PTR_ERR(bh);
539                 tmp = min(bsize - boff, newsize - size);
540                 BUG_ON(boff + tmp > bsize || tmp > bsize);
541                 memset(AFFS_DATA(bh) + boff, 0, tmp);
542                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
543                 affs_fix_checksum(sb, bh);
544                 mark_buffer_dirty_inode(bh, inode);
545                 size += tmp;
546                 bidx++;
547         } else if (bidx) {
548                 bh = affs_bread_ino(inode, bidx - 1, 0);
549                 if (IS_ERR(bh))
550                         return PTR_ERR(bh);
551         }
552
553         while (size < newsize) {
554                 prev_bh = bh;
555                 bh = affs_getzeroblk_ino(inode, bidx);
556                 if (IS_ERR(bh))
557                         goto out;
558                 tmp = min(bsize, newsize - size);
559                 BUG_ON(tmp > bsize);
560                 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
561                 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
562                 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
563                 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
564                 affs_fix_checksum(sb, bh);
565                 bh->b_state &= ~(1UL << BH_New);
566                 mark_buffer_dirty_inode(bh, inode);
567                 if (prev_bh) {
568                         u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
569                         if (tmp)
570                                 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
571                         AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
572                         affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
573                         mark_buffer_dirty_inode(prev_bh, inode);
574                         affs_brelse(prev_bh);
575                 }
576                 size += bsize;
577                 bidx++;
578         }
579         affs_brelse(bh);
580         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
581         return 0;
582
583 out:
584         inode->i_size = AFFS_I(inode)->mmu_private = newsize;
585         return PTR_ERR(bh);
586 }
587
588 static int
589 affs_readpage_ofs(struct file *file, struct page *page)
590 {
591         struct inode *inode = page->mapping->host;
592         u32 to;
593         int err;
594
595         pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
596         to = PAGE_CACHE_SIZE;
597         if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
598                 to = inode->i_size & ~PAGE_CACHE_MASK;
599                 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
600         }
601
602         err = affs_do_readpage_ofs(file, page, 0, to);
603         if (!err)
604                 SetPageUptodate(page);
605         unlock_page(page);
606         return err;
607 }
608
609 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
610                                 loff_t pos, unsigned len, unsigned flags,
611                                 struct page **pagep, void **fsdata)
612 {
613         struct inode *inode = mapping->host;
614         struct page *page;
615         pgoff_t index;
616         int err = 0;
617
618         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
619         if (pos > AFFS_I(inode)->mmu_private) {
620                 /* XXX: this probably leaves a too-big i_size in case of
621                  * failure. Should really be updating i_size at write_end time
622                  */
623                 err = affs_extent_file_ofs(inode, pos);
624                 if (err)
625                         return err;
626         }
627
628         index = pos >> PAGE_CACHE_SHIFT;
629         page = __grab_cache_page(mapping, index);
630         if (!page)
631                 return -ENOMEM;
632         *pagep = page;
633
634         if (PageUptodate(page))
635                 return 0;
636
637         /* XXX: inefficient but safe in the face of short writes */
638         err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
639         if (err) {
640                 unlock_page(page);
641                 page_cache_release(page);
642         }
643         return err;
644 }
645
646 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
647                                 loff_t pos, unsigned len, unsigned copied,
648                                 struct page *page, void *fsdata)
649 {
650         struct inode *inode = mapping->host;
651         struct super_block *sb = inode->i_sb;
652         struct buffer_head *bh, *prev_bh;
653         char *data;
654         u32 bidx, boff, bsize;
655         unsigned from, to;
656         u32 tmp;
657         int written;
658
659         from = pos & (PAGE_CACHE_SIZE - 1);
660         to = pos + len;
661         /*
662          * XXX: not sure if this can handle short copies (len < copied), but
663          * we don't have to, because the page should always be uptodate here,
664          * due to write_begin.
665          */
666
667         pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
668         bsize = AFFS_SB(sb)->s_data_blksize;
669         data = page_address(page);
670
671         bh = NULL;
672         written = 0;
673         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
674         bidx = tmp / bsize;
675         boff = tmp % bsize;
676         if (boff) {
677                 bh = affs_bread_ino(inode, bidx, 0);
678                 if (IS_ERR(bh))
679                         return PTR_ERR(bh);
680                 tmp = min(bsize - boff, to - from);
681                 BUG_ON(boff + tmp > bsize || tmp > bsize);
682                 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
683                 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
684                 affs_fix_checksum(sb, bh);
685                 mark_buffer_dirty_inode(bh, inode);
686                 written += tmp;
687                 from += tmp;
688                 bidx++;
689         } else if (bidx) {
690                 bh = affs_bread_ino(inode, bidx - 1, 0);
691                 if (IS_ERR(bh))
692                         return PTR_ERR(bh);
693         }
694         while (from + bsize <= to) {
695                 prev_bh = bh;
696                 bh = affs_getemptyblk_ino(inode, bidx);
697                 if (IS_ERR(bh))
698                         goto out;
699                 memcpy(AFFS_DATA(bh), data + from, bsize);
700                 if (buffer_new(bh)) {
701                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
702                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
703                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
704                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
705                         AFFS_DATA_HEAD(bh)->next = 0;
706                         bh->b_state &= ~(1UL << BH_New);
707                         if (prev_bh) {
708                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
709                                 if (tmp)
710                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
711                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
712                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
713                                 mark_buffer_dirty_inode(prev_bh, inode);
714                         }
715                 }
716                 affs_brelse(prev_bh);
717                 affs_fix_checksum(sb, bh);
718                 mark_buffer_dirty_inode(bh, inode);
719                 written += bsize;
720                 from += bsize;
721                 bidx++;
722         }
723         if (from < to) {
724                 prev_bh = bh;
725                 bh = affs_bread_ino(inode, bidx, 1);
726                 if (IS_ERR(bh))
727                         goto out;
728                 tmp = min(bsize, to - from);
729                 BUG_ON(tmp > bsize);
730                 memcpy(AFFS_DATA(bh), data + from, tmp);
731                 if (buffer_new(bh)) {
732                         AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
733                         AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
734                         AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
735                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
736                         AFFS_DATA_HEAD(bh)->next = 0;
737                         bh->b_state &= ~(1UL << BH_New);
738                         if (prev_bh) {
739                                 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
740                                 if (tmp)
741                                         affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
742                                 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
743                                 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
744                                 mark_buffer_dirty_inode(prev_bh, inode);
745                         }
746                 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
747                         AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
748                 affs_brelse(prev_bh);
749                 affs_fix_checksum(sb, bh);
750                 mark_buffer_dirty_inode(bh, inode);
751                 written += tmp;
752                 from += tmp;
753                 bidx++;
754         }
755         SetPageUptodate(page);
756
757 done:
758         affs_brelse(bh);
759         tmp = (page->index << PAGE_CACHE_SHIFT) + from;
760         if (tmp > inode->i_size)
761                 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
762
763         unlock_page(page);
764         page_cache_release(page);
765
766         return written;
767
768 out:
769         bh = prev_bh;
770         if (!written)
771                 written = PTR_ERR(bh);
772         goto done;
773 }
774
775 const struct address_space_operations affs_aops_ofs = {
776         .readpage = affs_readpage_ofs,
777         //.writepage = affs_writepage_ofs,
778         //.sync_page = affs_sync_page_ofs,
779         .write_begin = affs_write_begin_ofs,
780         .write_end = affs_write_end_ofs
781 };
782
783 /* Free any preallocated blocks. */
784
785 void
786 affs_free_prealloc(struct inode *inode)
787 {
788         struct super_block *sb = inode->i_sb;
789
790         pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
791
792         while (AFFS_I(inode)->i_pa_cnt) {
793                 AFFS_I(inode)->i_pa_cnt--;
794                 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
795         }
796 }
797
798 /* Truncate (or enlarge) a file to the requested size. */
799
800 void
801 affs_truncate(struct inode *inode)
802 {
803         struct super_block *sb = inode->i_sb;
804         u32 ext, ext_key;
805         u32 last_blk, blkcnt, blk;
806         u32 size;
807         struct buffer_head *ext_bh;
808         int i;
809
810         pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
811                  (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
812
813         last_blk = 0;
814         ext = 0;
815         if (inode->i_size) {
816                 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
817                 ext = last_blk / AFFS_SB(sb)->s_hashsize;
818         }
819
820         if (inode->i_size > AFFS_I(inode)->mmu_private) {
821                 struct address_space *mapping = inode->i_mapping;
822                 struct page *page;
823                 void *fsdata;
824                 u32 size = inode->i_size;
825                 int res;
826
827                 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
828                 if (!res)
829                         res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
830                 mark_inode_dirty(inode);
831                 return;
832         } else if (inode->i_size == AFFS_I(inode)->mmu_private)
833                 return;
834
835         // lock cache
836         ext_bh = affs_get_extblock(inode, ext);
837         if (IS_ERR(ext_bh)) {
838                 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
839                              ext, PTR_ERR(ext_bh));
840                 return;
841         }
842         if (AFFS_I(inode)->i_lc) {
843                 /* clear linear cache */
844                 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
845                 if (AFFS_I(inode)->i_lc_size > i) {
846                         AFFS_I(inode)->i_lc_size = i;
847                         for (; i < AFFS_LC_SIZE; i++)
848                                 AFFS_I(inode)->i_lc[i] = 0;
849                 }
850                 /* clear associative cache */
851                 for (i = 0; i < AFFS_AC_SIZE; i++)
852                         if (AFFS_I(inode)->i_ac[i].ext >= ext)
853                                 AFFS_I(inode)->i_ac[i].ext = 0;
854         }
855         ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
856
857         blkcnt = AFFS_I(inode)->i_blkcnt;
858         i = 0;
859         blk = last_blk;
860         if (inode->i_size) {
861                 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
862                 blk++;
863         } else
864                 AFFS_HEAD(ext_bh)->first_data = 0;
865         size = AFFS_SB(sb)->s_hashsize;
866         if (size > blkcnt - blk + i)
867                 size = blkcnt - blk + i;
868         for (; i < size; i++, blk++) {
869                 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
870                 AFFS_BLOCK(sb, ext_bh, i) = 0;
871         }
872         AFFS_TAIL(sb, ext_bh)->extension = 0;
873         affs_fix_checksum(sb, ext_bh);
874         mark_buffer_dirty_inode(ext_bh, inode);
875         affs_brelse(ext_bh);
876
877         if (inode->i_size) {
878                 AFFS_I(inode)->i_blkcnt = last_blk + 1;
879                 AFFS_I(inode)->i_extcnt = ext + 1;
880                 if (AFFS_SB(sb)->s_flags & SF_OFS) {
881                         struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
882                         u32 tmp;
883                         if (IS_ERR(ext_bh)) {
884                                 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
885                                              ext, PTR_ERR(ext_bh));
886                                 return;
887                         }
888                         tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
889                         AFFS_DATA_HEAD(bh)->next = 0;
890                         affs_adjust_checksum(bh, -tmp);
891                         affs_brelse(bh);
892                 }
893         } else {
894                 AFFS_I(inode)->i_blkcnt = 0;
895                 AFFS_I(inode)->i_extcnt = 1;
896         }
897         AFFS_I(inode)->mmu_private = inode->i_size;
898         // unlock cache
899
900         while (ext_key) {
901                 ext_bh = affs_bread(sb, ext_key);
902                 size = AFFS_SB(sb)->s_hashsize;
903                 if (size > blkcnt - blk)
904                         size = blkcnt - blk;
905                 for (i = 0; i < size; i++, blk++)
906                         affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
907                 affs_free_block(sb, ext_key);
908                 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
909                 affs_brelse(ext_bh);
910         }
911         affs_free_prealloc(inode);
912 }