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Merge commit 'v2.6.30.7' into mini2440-stable-v2.6.30
[linux-2.6/mini2440.git] / fs / affs / file.c
blob9246cb4aa018fafa3517685e7d7fa1572f2e5a16
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 pr_debug("AFFS: open(%lu,%d)\n",
50 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
51 atomic_inc(&AFFS_I(inode)->i_opencnt);
52 return 0;
53 }
54
55 static int
56 affs_file_release(struct inode *inode, struct file *filp)
57 {
58 pr_debug("AFFS: release(%lu, %d)\n",
59 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
60
61 if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
62 mutex_lock(&inode->i_mutex);
63 if (inode->i_size != AFFS_I(inode)->mmu_private)
64 affs_truncate(inode);
65 affs_free_prealloc(inode);
66 mutex_unlock(&inode->i_mutex);
67 }
68
69 return 0;
70 }
71
72 static int
73 affs_grow_extcache(struct inode *inode, u32 lc_idx)
74 {
75 struct super_block *sb = inode->i_sb;
76 struct buffer_head *bh;
77 u32 lc_max;
78 int i, j, key;
79
80 if (!AFFS_I(inode)->i_lc) {
81 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
82 if (!ptr)
83 return -ENOMEM;
84 AFFS_I(inode)->i_lc = (u32 *)ptr;
85 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
86 }
87
88 lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
89
90 if (AFFS_I(inode)->i_extcnt > lc_max) {
91 u32 lc_shift, lc_mask, tmp, off;
92
93 /* need to recalculate linear cache, start from old size */
94 lc_shift = AFFS_I(inode)->i_lc_shift;
95 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
96 for (; tmp; tmp >>= 1)
97 lc_shift++;
98 lc_mask = (1 << lc_shift) - 1;
99
100 /* fix idx and old size to new shift */
101 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
102 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
103
104 /* first shrink old cache to make more space */
105 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
106 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
107 AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
108
109 AFFS_I(inode)->i_lc_shift = lc_shift;
110 AFFS_I(inode)->i_lc_mask = lc_mask;
111 }
112
113 /* fill cache to the needed index */
114 i = AFFS_I(inode)->i_lc_size;
115 AFFS_I(inode)->i_lc_size = lc_idx + 1;
116 for (; i <= lc_idx; i++) {
117 if (!i) {
118 AFFS_I(inode)->i_lc[0] = inode->i_ino;
119 continue;
120 }
121 key = AFFS_I(inode)->i_lc[i - 1];
122 j = AFFS_I(inode)->i_lc_mask + 1;
123 // unlock cache
124 for (; j > 0; j--) {
125 bh = affs_bread(sb, key);
126 if (!bh)
127 goto err;
128 key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
129 affs_brelse(bh);
130 }
131 // lock cache
132 AFFS_I(inode)->i_lc[i] = key;
133 }
134
135 return 0;
136
137 err:
138 // lock cache
139 return -EIO;
140 }
141
142 static struct buffer_head *
143 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
144 {
145 struct super_block *sb = inode->i_sb;
146 struct buffer_head *new_bh;
147 u32 blocknr, tmp;
148
149 blocknr = affs_alloc_block(inode, bh->b_blocknr);
150 if (!blocknr)
151 return ERR_PTR(-ENOSPC);
152
153 new_bh = affs_getzeroblk(sb, blocknr);
154 if (!new_bh) {
155 affs_free_block(sb, blocknr);
156 return ERR_PTR(-EIO);
157 }
158
159 AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
160 AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
161 AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
162 AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
163 affs_fix_checksum(sb, new_bh);
164
165 mark_buffer_dirty_inode(new_bh, inode);
166
167 tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
168 if (tmp)
169 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
170 AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
171 affs_adjust_checksum(bh, blocknr - tmp);
172 mark_buffer_dirty_inode(bh, inode);
173
174 AFFS_I(inode)->i_extcnt++;
175 mark_inode_dirty(inode);
176
177 return new_bh;
178 }
179
180 static inline struct buffer_head *
181 affs_get_extblock(struct inode *inode, u32 ext)
182 {
183 /* inline the simplest case: same extended block as last time */
184 struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
185 if (ext == AFFS_I(inode)->i_ext_last)
186 get_bh(bh);
187 else
188 /* we have to do more (not inlined) */
189 bh = affs_get_extblock_slow(inode, ext);
190
191 return bh;
192 }
193
194 static struct buffer_head *
195 affs_get_extblock_slow(struct inode *inode, u32 ext)
196 {
197 struct super_block *sb = inode->i_sb;
198 struct buffer_head *bh;
199 u32 ext_key;
200 u32 lc_idx, lc_off, ac_idx;
201 u32 tmp, idx;
202
203 if (ext == AFFS_I(inode)->i_ext_last + 1) {
204 /* read the next extended block from the current one */
205 bh = AFFS_I(inode)->i_ext_bh;
206 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
207 if (ext < AFFS_I(inode)->i_extcnt)
208 goto read_ext;
209 if (ext > AFFS_I(inode)->i_extcnt)
210 BUG();
211 bh = affs_alloc_extblock(inode, bh, ext);
212 if (IS_ERR(bh))
213 return bh;
214 goto store_ext;
215 }
216
217 if (ext == 0) {
218 /* we seek back to the file header block */
219 ext_key = inode->i_ino;
220 goto read_ext;
221 }
222
223 if (ext >= AFFS_I(inode)->i_extcnt) {
224 struct buffer_head *prev_bh;
225
226 /* allocate a new extended block */
227 if (ext > AFFS_I(inode)->i_extcnt)
228 BUG();
229
230 /* get previous extended block */
231 prev_bh = affs_get_extblock(inode, ext - 1);
232 if (IS_ERR(prev_bh))
233 return prev_bh;
234 bh = affs_alloc_extblock(inode, prev_bh, ext);
235 affs_brelse(prev_bh);
236 if (IS_ERR(bh))
237 return bh;
238 goto store_ext;
239 }
240
241 again:
242 /* check if there is an extended cache and whether it's large enough */
243 lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
244 lc_off = ext & AFFS_I(inode)->i_lc_mask;
245
246 if (lc_idx >= AFFS_I(inode)->i_lc_size) {
247 int err;
248
249 err = affs_grow_extcache(inode, lc_idx);
250 if (err)
251 return ERR_PTR(err);
252 goto again;
253 }
254
255 /* every n'th key we find in the linear cache */
256 if (!lc_off) {
257 ext_key = AFFS_I(inode)->i_lc[lc_idx];
258 goto read_ext;
259 }
260
261 /* maybe it's still in the associative cache */
262 ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
263 if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
264 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
265 goto read_ext;
266 }
267
268 /* try to find one of the previous extended blocks */
269 tmp = ext;
270 idx = ac_idx;
271 while (--tmp, --lc_off > 0) {
272 idx = (idx - 1) & AFFS_AC_MASK;
273 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
274 ext_key = AFFS_I(inode)->i_ac[idx].key;
275 goto find_ext;
276 }
277 }
278
279 /* fall back to the linear cache */
280 ext_key = AFFS_I(inode)->i_lc[lc_idx];
281 find_ext:
282 /* read all extended blocks until we find the one we need */
283 //unlock cache
284 do {
285 bh = affs_bread(sb, ext_key);
286 if (!bh)
287 goto err_bread;
288 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
289 affs_brelse(bh);
290 tmp++;
291 } while (tmp < ext);
292 //lock cache
293
294 /* store it in the associative cache */
295 // recalculate ac_idx?
296 AFFS_I(inode)->i_ac[ac_idx].ext = ext;
297 AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
298
299 read_ext:
300 /* finally read the right extended block */
301 //unlock cache
302 bh = affs_bread(sb, ext_key);
303 if (!bh)
304 goto err_bread;
305 //lock cache
306
307 store_ext:
308 /* release old cached extended block and store the new one */
309 affs_brelse(AFFS_I(inode)->i_ext_bh);
310 AFFS_I(inode)->i_ext_last = ext;
311 AFFS_I(inode)->i_ext_bh = bh;
312 get_bh(bh);
313
314 return bh;
315
316 err_bread:
317 affs_brelse(bh);
318 return ERR_PTR(-EIO);
319 }
320
321 static int
322 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
323 {
324 struct super_block *sb = inode->i_sb;
325 struct buffer_head *ext_bh;
326 u32 ext;
327
328 pr_debug("AFFS: get_block(%u, %lu)\n", (u32)inode->i_ino, (unsigned long)block);
329
330 BUG_ON(block > (sector_t)0x7fffffffUL);
331
332 if (block >= AFFS_I(inode)->i_blkcnt) {
333 if (block > AFFS_I(inode)->i_blkcnt || !create)
334 goto err_big;
335 } else
336 create = 0;
337
338 //lock cache
339 affs_lock_ext(inode);
340
341 ext = (u32)block / AFFS_SB(sb)->s_hashsize;
342 block -= ext * AFFS_SB(sb)->s_hashsize;
343 ext_bh = affs_get_extblock(inode, ext);
344 if (IS_ERR(ext_bh))
345 goto err_ext;
346 map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
347
348 if (create) {
349 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
350 if (!blocknr)
351 goto err_alloc;
352 set_buffer_new(bh_result);
353 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
354 AFFS_I(inode)->i_blkcnt++;
355
356 /* store new block */
357 if (bh_result->b_blocknr)
358 affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
359 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
360 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
361 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
362 bh_result->b_blocknr = blocknr;
363
364 if (!block) {
365 /* insert first block into header block */
366 u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
367 if (tmp)
368 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
369 AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
370 affs_adjust_checksum(ext_bh, blocknr - tmp);
371 }
372 }
373
374 affs_brelse(ext_bh);
375 //unlock cache
376 affs_unlock_ext(inode);
377 return 0;
378
379 err_big:
380 affs_error(inode->i_sb,"get_block","strange block request %d", block);
381 return -EIO;
382 err_ext:
383 // unlock cache
384 affs_unlock_ext(inode);
385 return PTR_ERR(ext_bh);
386 err_alloc:
387 brelse(ext_bh);
388 clear_buffer_mapped(bh_result);
389 bh_result->b_bdev = NULL;
390 // unlock cache
391 affs_unlock_ext(inode);
392 return -ENOSPC;
393 }
394
395 static int affs_writepage(struct page *page, struct writeback_control *wbc)
396 {
397 return block_write_full_page(page, affs_get_block, wbc);
398 }
399
400 static int affs_readpage(struct file *file, struct page *page)
401 {
402 return block_read_full_page(page, affs_get_block);
403 }
404
405 static int affs_write_begin(struct file *file, struct address_space *mapping,
406 loff_t pos, unsigned len, unsigned flags,
407 struct page **pagep, void **fsdata)
408 {
409 *pagep = NULL;
410 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
411 affs_get_block,
412 &AFFS_I(mapping->host)->mmu_private);
413 }
414
415 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
416 {
417 return generic_block_bmap(mapping,block,affs_get_block);
418 }
419
420 const struct address_space_operations affs_aops = {
421 .readpage = affs_readpage,
422 .writepage = affs_writepage,
423 .sync_page = block_sync_page,
424 .write_begin = affs_write_begin,
425 .write_end = generic_write_end,
426 .bmap = _affs_bmap
427 };
428
429 static inline struct buffer_head *
430 affs_bread_ino(struct inode *inode, int block, int create)
431 {
432 struct buffer_head *bh, tmp_bh;
433 int err;
434
435 tmp_bh.b_state = 0;
436 err = affs_get_block(inode, block, &tmp_bh, create);
437 if (!err) {
438 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
439 if (bh) {
440 bh->b_state |= tmp_bh.b_state;
441 return bh;
442 }
443 err = -EIO;
444 }
445 return ERR_PTR(err);
446 }
447
448 static inline struct buffer_head *
449 affs_getzeroblk_ino(struct inode *inode, int block)
450 {
451 struct buffer_head *bh, tmp_bh;
452 int err;
453
454 tmp_bh.b_state = 0;
455 err = affs_get_block(inode, block, &tmp_bh, 1);
456 if (!err) {
457 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
458 if (bh) {
459 bh->b_state |= tmp_bh.b_state;
460 return bh;
461 }
462 err = -EIO;
463 }
464 return ERR_PTR(err);
465 }
466
467 static inline struct buffer_head *
468 affs_getemptyblk_ino(struct inode *inode, int block)
469 {
470 struct buffer_head *bh, tmp_bh;
471 int err;
472
473 tmp_bh.b_state = 0;
474 err = affs_get_block(inode, block, &tmp_bh, 1);
475 if (!err) {
476 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
477 if (bh) {
478 bh->b_state |= tmp_bh.b_state;
479 return bh;
480 }
481 err = -EIO;
482 }
483 return ERR_PTR(err);
484 }
485
486 static int
487 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
488 {
489 struct inode *inode = page->mapping->host;
490 struct super_block *sb = inode->i_sb;
491 struct buffer_head *bh;
492 char *data;
493 u32 bidx, boff, bsize;
494 u32 tmp;
495
496 pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
497 BUG_ON(from > to || to > PAGE_CACHE_SIZE);
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 BUG_ON(from + tmp > to || tmp > bsize);
511 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
512 affs_brelse(bh);
513 bidx++;
514 from += tmp;
515 boff = 0;
516 }
517 flush_dcache_page(page);
518 kunmap(page);
519 return 0;
520 }
521
522 static int
523 affs_extent_file_ofs(struct inode *inode, u32 newsize)
524 {
525 struct super_block *sb = inode->i_sb;
526 struct buffer_head *bh, *prev_bh;
527 u32 bidx, boff;
528 u32 size, bsize;
529 u32 tmp;
530
531 pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
532 bsize = AFFS_SB(sb)->s_data_blksize;
533 bh = NULL;
534 size = AFFS_I(inode)->mmu_private;
535 bidx = size / bsize;
536 boff = size % bsize;
537 if (boff) {
538 bh = affs_bread_ino(inode, bidx, 0);
539 if (IS_ERR(bh))
540 return PTR_ERR(bh);
541 tmp = min(bsize - boff, newsize - size);
542 BUG_ON(boff + tmp > bsize || tmp > bsize);
543 memset(AFFS_DATA(bh) + boff, 0, tmp);
544 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
545 affs_fix_checksum(sb, bh);
546 mark_buffer_dirty_inode(bh, inode);
547 size += tmp;
548 bidx++;
549 } else if (bidx) {
550 bh = affs_bread_ino(inode, bidx - 1, 0);
551 if (IS_ERR(bh))
552 return PTR_ERR(bh);
553 }
554
555 while (size < newsize) {
556 prev_bh = bh;
557 bh = affs_getzeroblk_ino(inode, bidx);
558 if (IS_ERR(bh))
559 goto out;
560 tmp = min(bsize, newsize - size);
561 BUG_ON(tmp > bsize);
562 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
563 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
564 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
565 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
566 affs_fix_checksum(sb, bh);
567 bh->b_state &= ~(1UL << BH_New);
568 mark_buffer_dirty_inode(bh, inode);
569 if (prev_bh) {
570 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
571 if (tmp)
572 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
573 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
574 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
575 mark_buffer_dirty_inode(prev_bh, inode);
576 affs_brelse(prev_bh);
577 }
578 size += bsize;
579 bidx++;
580 }
581 affs_brelse(bh);
582 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
583 return 0;
584
585 out:
586 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
587 return PTR_ERR(bh);
588 }
589
590 static int
591 affs_readpage_ofs(struct file *file, struct page *page)
592 {
593 struct inode *inode = page->mapping->host;
594 u32 to;
595 int err;
596
597 pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
598 to = PAGE_CACHE_SIZE;
599 if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
600 to = inode->i_size & ~PAGE_CACHE_MASK;
601 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
602 }
603
604 err = affs_do_readpage_ofs(file, page, 0, to);
605 if (!err)
606 SetPageUptodate(page);
607 unlock_page(page);
608 return err;
609 }
610
611 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
612 loff_t pos, unsigned len, unsigned flags,
613 struct page **pagep, void **fsdata)
614 {
615 struct inode *inode = mapping->host;
616 struct page *page;
617 pgoff_t index;
618 int err = 0;
619
620 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
621 if (pos > AFFS_I(inode)->mmu_private) {
622 /* XXX: this probably leaves a too-big i_size in case of
623 * failure. Should really be updating i_size at write_end time
624 */
625 err = affs_extent_file_ofs(inode, pos);
626 if (err)
627 return err;
628 }
629
630 index = pos >> PAGE_CACHE_SHIFT;
631 page = grab_cache_page_write_begin(mapping, index, flags);
632 if (!page)
633 return -ENOMEM;
634 *pagep = page;
635
636 if (PageUptodate(page))
637 return 0;
638
639 /* XXX: inefficient but safe in the face of short writes */
640 err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
641 if (err) {
642 unlock_page(page);
643 page_cache_release(page);
644 }
645 return err;
646 }
647
648 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
649 loff_t pos, unsigned len, unsigned copied,
650 struct page *page, void *fsdata)
651 {
652 struct inode *inode = mapping->host;
653 struct super_block *sb = inode->i_sb;
654 struct buffer_head *bh, *prev_bh;
655 char *data;
656 u32 bidx, boff, bsize;
657 unsigned from, to;
658 u32 tmp;
659 int written;
660
661 from = pos & (PAGE_CACHE_SIZE - 1);
662 to = pos + len;
663 /*
664 * XXX: not sure if this can handle short copies (len < copied), but
665 * we don't have to, because the page should always be uptodate here,
666 * due to write_begin.
667 */
668
669 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
670 bsize = AFFS_SB(sb)->s_data_blksize;
671 data = page_address(page);
672
673 bh = NULL;
674 written = 0;
675 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
676 bidx = tmp / bsize;
677 boff = tmp % bsize;
678 if (boff) {
679 bh = affs_bread_ino(inode, bidx, 0);
680 if (IS_ERR(bh))
681 return PTR_ERR(bh);
682 tmp = min(bsize - boff, to - from);
683 BUG_ON(boff + tmp > bsize || tmp > bsize);
684 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
685 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
686 affs_fix_checksum(sb, bh);
687 mark_buffer_dirty_inode(bh, inode);
688 written += tmp;
689 from += tmp;
690 bidx++;
691 } else if (bidx) {
692 bh = affs_bread_ino(inode, bidx - 1, 0);
693 if (IS_ERR(bh))
694 return PTR_ERR(bh);
695 }
696 while (from + bsize <= to) {
697 prev_bh = bh;
698 bh = affs_getemptyblk_ino(inode, bidx);
699 if (IS_ERR(bh))
700 goto out;
701 memcpy(AFFS_DATA(bh), data + from, bsize);
702 if (buffer_new(bh)) {
703 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
704 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
705 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
706 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
707 AFFS_DATA_HEAD(bh)->next = 0;
708 bh->b_state &= ~(1UL << BH_New);
709 if (prev_bh) {
710 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
711 if (tmp)
712 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
713 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
714 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
715 mark_buffer_dirty_inode(prev_bh, inode);
716 }
717 }
718 affs_brelse(prev_bh);
719 affs_fix_checksum(sb, bh);
720 mark_buffer_dirty_inode(bh, inode);
721 written += bsize;
722 from += bsize;
723 bidx++;
724 }
725 if (from < to) {
726 prev_bh = bh;
727 bh = affs_bread_ino(inode, bidx, 1);
728 if (IS_ERR(bh))
729 goto out;
730 tmp = min(bsize, to - from);
731 BUG_ON(tmp > bsize);
732 memcpy(AFFS_DATA(bh), data + from, tmp);
733 if (buffer_new(bh)) {
734 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
735 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
736 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
737 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
738 AFFS_DATA_HEAD(bh)->next = 0;
739 bh->b_state &= ~(1UL << BH_New);
740 if (prev_bh) {
741 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
742 if (tmp)
743 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
744 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
745 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
746 mark_buffer_dirty_inode(prev_bh, inode);
747 }
748 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
749 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
750 affs_brelse(prev_bh);
751 affs_fix_checksum(sb, bh);
752 mark_buffer_dirty_inode(bh, inode);
753 written += tmp;
754 from += tmp;
755 bidx++;
756 }
757 SetPageUptodate(page);
758
759 done:
760 affs_brelse(bh);
761 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
762 if (tmp > inode->i_size)
763 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
764
765 unlock_page(page);
766 page_cache_release(page);
767
768 return written;
769
770 out:
771 bh = prev_bh;
772 if (!written)
773 written = PTR_ERR(bh);
774 goto done;
775 }
776
777 const struct address_space_operations affs_aops_ofs = {
778 .readpage = affs_readpage_ofs,
779 //.writepage = affs_writepage_ofs,
780 //.sync_page = affs_sync_page_ofs,
781 .write_begin = affs_write_begin_ofs,
782 .write_end = affs_write_end_ofs
783 };
784
785 /* Free any preallocated blocks. */
786
787 void
788 affs_free_prealloc(struct inode *inode)
789 {
790 struct super_block *sb = inode->i_sb;
791
792 pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
793
794 while (AFFS_I(inode)->i_pa_cnt) {
795 AFFS_I(inode)->i_pa_cnt--;
796 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
797 }
798 }
799
800 /* Truncate (or enlarge) a file to the requested size. */
801
802 void
803 affs_truncate(struct inode *inode)
804 {
805 struct super_block *sb = inode->i_sb;
806 u32 ext, ext_key;
807 u32 last_blk, blkcnt, blk;
808 u32 size;
809 struct buffer_head *ext_bh;
810 int i;
811
812 pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
813 (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
814
815 last_blk = 0;
816 ext = 0;
817 if (inode->i_size) {
818 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
819 ext = last_blk / AFFS_SB(sb)->s_hashsize;
820 }
821
822 if (inode->i_size > AFFS_I(inode)->mmu_private) {
823 struct address_space *mapping = inode->i_mapping;
824 struct page *page;
825 void *fsdata;
826 u32 size = inode->i_size;
827 int res;
828
829 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
830 if (!res)
831 res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
832 else
833 inode->i_size = AFFS_I(inode)->mmu_private;
834 mark_inode_dirty(inode);
835 return;
836 } else if (inode->i_size == AFFS_I(inode)->mmu_private)
837 return;
838
839 // lock cache
840 ext_bh = affs_get_extblock(inode, ext);
841 if (IS_ERR(ext_bh)) {
842 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
843 ext, PTR_ERR(ext_bh));
844 return;
845 }
846 if (AFFS_I(inode)->i_lc) {
847 /* clear linear cache */
848 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
849 if (AFFS_I(inode)->i_lc_size > i) {
850 AFFS_I(inode)->i_lc_size = i;
851 for (; i < AFFS_LC_SIZE; i++)
852 AFFS_I(inode)->i_lc[i] = 0;
853 }
854 /* clear associative cache */
855 for (i = 0; i < AFFS_AC_SIZE; i++)
856 if (AFFS_I(inode)->i_ac[i].ext >= ext)
857 AFFS_I(inode)->i_ac[i].ext = 0;
858 }
859 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
860
861 blkcnt = AFFS_I(inode)->i_blkcnt;
862 i = 0;
863 blk = last_blk;
864 if (inode->i_size) {
865 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
866 blk++;
867 } else
868 AFFS_HEAD(ext_bh)->first_data = 0;
869 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
870 size = AFFS_SB(sb)->s_hashsize;
871 if (size > blkcnt - blk + i)
872 size = blkcnt - blk + i;
873 for (; i < size; i++, blk++) {
874 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
875 AFFS_BLOCK(sb, ext_bh, i) = 0;
876 }
877 AFFS_TAIL(sb, ext_bh)->extension = 0;
878 affs_fix_checksum(sb, ext_bh);
879 mark_buffer_dirty_inode(ext_bh, inode);
880 affs_brelse(ext_bh);
881
882 if (inode->i_size) {
883 AFFS_I(inode)->i_blkcnt = last_blk + 1;
884 AFFS_I(inode)->i_extcnt = ext + 1;
885 if (AFFS_SB(sb)->s_flags & SF_OFS) {
886 struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
887 u32 tmp;
888 if (IS_ERR(ext_bh)) {
889 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
890 ext, PTR_ERR(ext_bh));
891 return;
892 }
893 tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
894 AFFS_DATA_HEAD(bh)->next = 0;
895 affs_adjust_checksum(bh, -tmp);
896 affs_brelse(bh);
897 }
898 } else {
899 AFFS_I(inode)->i_blkcnt = 0;
900 AFFS_I(inode)->i_extcnt = 1;
901 }
902 AFFS_I(inode)->mmu_private = inode->i_size;
903 // unlock cache
904
905 while (ext_key) {
906 ext_bh = affs_bread(sb, ext_key);
907 size = AFFS_SB(sb)->s_hashsize;
908 if (size > blkcnt - blk)
909 size = blkcnt - blk;
910 for (i = 0; i < size; i++, blk++)
911 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
912 affs_free_block(sb, ext_key);
913 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
914 affs_brelse(ext_bh);
915 }
916 affs_free_prealloc(inode);
917 }
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