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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / fs / affs / file.c
blob2f4c935cb3276e544b321e89bfddd4fa2525d2d5
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 .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 int ret;
410
411 *pagep = NULL;
412 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
413 affs_get_block,
414 &AFFS_I(mapping->host)->mmu_private);
415 if (unlikely(ret)) {
416 loff_t isize = mapping->host->i_size;
417 if (pos + len > isize)
418 vmtruncate(mapping->host, isize);
419 }
420
421 return ret;
422 }
423
424 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
425 {
426 return generic_block_bmap(mapping,block,affs_get_block);
427 }
428
429 const struct address_space_operations affs_aops = {
430 .readpage = affs_readpage,
431 .writepage = affs_writepage,
432 .write_begin = affs_write_begin,
433 .write_end = generic_write_end,
434 .bmap = _affs_bmap
435 };
436
437 static inline struct buffer_head *
438 affs_bread_ino(struct inode *inode, int block, int create)
439 {
440 struct buffer_head *bh, tmp_bh;
441 int err;
442
443 tmp_bh.b_state = 0;
444 err = affs_get_block(inode, block, &tmp_bh, create);
445 if (!err) {
446 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
447 if (bh) {
448 bh->b_state |= tmp_bh.b_state;
449 return bh;
450 }
451 err = -EIO;
452 }
453 return ERR_PTR(err);
454 }
455
456 static inline struct buffer_head *
457 affs_getzeroblk_ino(struct inode *inode, int block)
458 {
459 struct buffer_head *bh, tmp_bh;
460 int err;
461
462 tmp_bh.b_state = 0;
463 err = affs_get_block(inode, block, &tmp_bh, 1);
464 if (!err) {
465 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
466 if (bh) {
467 bh->b_state |= tmp_bh.b_state;
468 return bh;
469 }
470 err = -EIO;
471 }
472 return ERR_PTR(err);
473 }
474
475 static inline struct buffer_head *
476 affs_getemptyblk_ino(struct inode *inode, int block)
477 {
478 struct buffer_head *bh, tmp_bh;
479 int err;
480
481 tmp_bh.b_state = 0;
482 err = affs_get_block(inode, block, &tmp_bh, 1);
483 if (!err) {
484 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
485 if (bh) {
486 bh->b_state |= tmp_bh.b_state;
487 return bh;
488 }
489 err = -EIO;
490 }
491 return ERR_PTR(err);
492 }
493
494 static int
495 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
496 {
497 struct inode *inode = page->mapping->host;
498 struct super_block *sb = inode->i_sb;
499 struct buffer_head *bh;
500 char *data;
501 u32 bidx, boff, bsize;
502 u32 tmp;
503
504 pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
505 BUG_ON(from > to || to > PAGE_CACHE_SIZE);
506 kmap(page);
507 data = page_address(page);
508 bsize = AFFS_SB(sb)->s_data_blksize;
509 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
510 bidx = tmp / bsize;
511 boff = tmp % bsize;
512
513 while (from < to) {
514 bh = affs_bread_ino(inode, bidx, 0);
515 if (IS_ERR(bh))
516 return PTR_ERR(bh);
517 tmp = min(bsize - boff, to - from);
518 BUG_ON(from + tmp > to || tmp > bsize);
519 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
520 affs_brelse(bh);
521 bidx++;
522 from += tmp;
523 boff = 0;
524 }
525 flush_dcache_page(page);
526 kunmap(page);
527 return 0;
528 }
529
530 static int
531 affs_extent_file_ofs(struct inode *inode, u32 newsize)
532 {
533 struct super_block *sb = inode->i_sb;
534 struct buffer_head *bh, *prev_bh;
535 u32 bidx, boff;
536 u32 size, bsize;
537 u32 tmp;
538
539 pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
540 bsize = AFFS_SB(sb)->s_data_blksize;
541 bh = NULL;
542 size = AFFS_I(inode)->mmu_private;
543 bidx = size / bsize;
544 boff = size % bsize;
545 if (boff) {
546 bh = affs_bread_ino(inode, bidx, 0);
547 if (IS_ERR(bh))
548 return PTR_ERR(bh);
549 tmp = min(bsize - boff, newsize - size);
550 BUG_ON(boff + tmp > bsize || tmp > bsize);
551 memset(AFFS_DATA(bh) + boff, 0, tmp);
552 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
553 affs_fix_checksum(sb, bh);
554 mark_buffer_dirty_inode(bh, inode);
555 size += tmp;
556 bidx++;
557 } else if (bidx) {
558 bh = affs_bread_ino(inode, bidx - 1, 0);
559 if (IS_ERR(bh))
560 return PTR_ERR(bh);
561 }
562
563 while (size < newsize) {
564 prev_bh = bh;
565 bh = affs_getzeroblk_ino(inode, bidx);
566 if (IS_ERR(bh))
567 goto out;
568 tmp = min(bsize, newsize - size);
569 BUG_ON(tmp > bsize);
570 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
571 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
572 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
573 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
574 affs_fix_checksum(sb, bh);
575 bh->b_state &= ~(1UL << BH_New);
576 mark_buffer_dirty_inode(bh, inode);
577 if (prev_bh) {
578 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
579 if (tmp)
580 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
581 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
582 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
583 mark_buffer_dirty_inode(prev_bh, inode);
584 affs_brelse(prev_bh);
585 }
586 size += bsize;
587 bidx++;
588 }
589 affs_brelse(bh);
590 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
591 return 0;
592
593 out:
594 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
595 return PTR_ERR(bh);
596 }
597
598 static int
599 affs_readpage_ofs(struct file *file, struct page *page)
600 {
601 struct inode *inode = page->mapping->host;
602 u32 to;
603 int err;
604
605 pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
606 to = PAGE_CACHE_SIZE;
607 if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
608 to = inode->i_size & ~PAGE_CACHE_MASK;
609 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
610 }
611
612 err = affs_do_readpage_ofs(file, page, 0, to);
613 if (!err)
614 SetPageUptodate(page);
615 unlock_page(page);
616 return err;
617 }
618
619 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
620 loff_t pos, unsigned len, unsigned flags,
621 struct page **pagep, void **fsdata)
622 {
623 struct inode *inode = mapping->host;
624 struct page *page;
625 pgoff_t index;
626 int err = 0;
627
628 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
629 if (pos > AFFS_I(inode)->mmu_private) {
630 /* XXX: this probably leaves a too-big i_size in case of
631 * failure. Should really be updating i_size at write_end time
632 */
633 err = affs_extent_file_ofs(inode, pos);
634 if (err)
635 return err;
636 }
637
638 index = pos >> PAGE_CACHE_SHIFT;
639 page = grab_cache_page_write_begin(mapping, index, flags);
640 if (!page)
641 return -ENOMEM;
642 *pagep = page;
643
644 if (PageUptodate(page))
645 return 0;
646
647 /* XXX: inefficient but safe in the face of short writes */
648 err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
649 if (err) {
650 unlock_page(page);
651 page_cache_release(page);
652 }
653 return err;
654 }
655
656 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
657 loff_t pos, unsigned len, unsigned copied,
658 struct page *page, void *fsdata)
659 {
660 struct inode *inode = mapping->host;
661 struct super_block *sb = inode->i_sb;
662 struct buffer_head *bh, *prev_bh;
663 char *data;
664 u32 bidx, boff, bsize;
665 unsigned from, to;
666 u32 tmp;
667 int written;
668
669 from = pos & (PAGE_CACHE_SIZE - 1);
670 to = pos + len;
671 /*
672 * XXX: not sure if this can handle short copies (len < copied), but
673 * we don't have to, because the page should always be uptodate here,
674 * due to write_begin.
675 */
676
677 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
678 bsize = AFFS_SB(sb)->s_data_blksize;
679 data = page_address(page);
680
681 bh = NULL;
682 written = 0;
683 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
684 bidx = tmp / bsize;
685 boff = tmp % bsize;
686 if (boff) {
687 bh = affs_bread_ino(inode, bidx, 0);
688 if (IS_ERR(bh))
689 return PTR_ERR(bh);
690 tmp = min(bsize - boff, to - from);
691 BUG_ON(boff + tmp > bsize || tmp > bsize);
692 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
693 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
694 affs_fix_checksum(sb, bh);
695 mark_buffer_dirty_inode(bh, inode);
696 written += tmp;
697 from += tmp;
698 bidx++;
699 } else if (bidx) {
700 bh = affs_bread_ino(inode, bidx - 1, 0);
701 if (IS_ERR(bh))
702 return PTR_ERR(bh);
703 }
704 while (from + bsize <= to) {
705 prev_bh = bh;
706 bh = affs_getemptyblk_ino(inode, bidx);
707 if (IS_ERR(bh))
708 goto out;
709 memcpy(AFFS_DATA(bh), data + from, bsize);
710 if (buffer_new(bh)) {
711 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
712 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
713 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
714 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
715 AFFS_DATA_HEAD(bh)->next = 0;
716 bh->b_state &= ~(1UL << BH_New);
717 if (prev_bh) {
718 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
719 if (tmp)
720 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
721 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
722 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
723 mark_buffer_dirty_inode(prev_bh, inode);
724 }
725 }
726 affs_brelse(prev_bh);
727 affs_fix_checksum(sb, bh);
728 mark_buffer_dirty_inode(bh, inode);
729 written += bsize;
730 from += bsize;
731 bidx++;
732 }
733 if (from < to) {
734 prev_bh = bh;
735 bh = affs_bread_ino(inode, bidx, 1);
736 if (IS_ERR(bh))
737 goto out;
738 tmp = min(bsize, to - from);
739 BUG_ON(tmp > bsize);
740 memcpy(AFFS_DATA(bh), data + from, tmp);
741 if (buffer_new(bh)) {
742 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
743 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
744 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
745 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
746 AFFS_DATA_HEAD(bh)->next = 0;
747 bh->b_state &= ~(1UL << BH_New);
748 if (prev_bh) {
749 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
750 if (tmp)
751 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
752 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
753 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
754 mark_buffer_dirty_inode(prev_bh, inode);
755 }
756 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
757 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
758 affs_brelse(prev_bh);
759 affs_fix_checksum(sb, bh);
760 mark_buffer_dirty_inode(bh, inode);
761 written += tmp;
762 from += tmp;
763 bidx++;
764 }
765 SetPageUptodate(page);
766
767 done:
768 affs_brelse(bh);
769 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
770 if (tmp > inode->i_size)
771 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
772
773 unlock_page(page);
774 page_cache_release(page);
775
776 return written;
777
778 out:
779 bh = prev_bh;
780 if (!written)
781 written = PTR_ERR(bh);
782 goto done;
783 }
784
785 const struct address_space_operations affs_aops_ofs = {
786 .readpage = affs_readpage_ofs,
787 //.writepage = affs_writepage_ofs,
788 .write_begin = affs_write_begin_ofs,
789 .write_end = affs_write_end_ofs
790 };
791
792 /* Free any preallocated blocks. */
793
794 void
795 affs_free_prealloc(struct inode *inode)
796 {
797 struct super_block *sb = inode->i_sb;
798
799 pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
800
801 while (AFFS_I(inode)->i_pa_cnt) {
802 AFFS_I(inode)->i_pa_cnt--;
803 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
804 }
805 }
806
807 /* Truncate (or enlarge) a file to the requested size. */
808
809 void
810 affs_truncate(struct inode *inode)
811 {
812 struct super_block *sb = inode->i_sb;
813 u32 ext, ext_key;
814 u32 last_blk, blkcnt, blk;
815 u32 size;
816 struct buffer_head *ext_bh;
817 int i;
818
819 pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
820 (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
821
822 last_blk = 0;
823 ext = 0;
824 if (inode->i_size) {
825 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
826 ext = last_blk / AFFS_SB(sb)->s_hashsize;
827 }
828
829 if (inode->i_size > AFFS_I(inode)->mmu_private) {
830 struct address_space *mapping = inode->i_mapping;
831 struct page *page;
832 void *fsdata;
833 u32 size = inode->i_size;
834 int res;
835
836 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
837 if (!res)
838 res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
839 else
840 inode->i_size = AFFS_I(inode)->mmu_private;
841 mark_inode_dirty(inode);
842 return;
843 } else if (inode->i_size == AFFS_I(inode)->mmu_private)
844 return;
845
846 // lock cache
847 ext_bh = affs_get_extblock(inode, ext);
848 if (IS_ERR(ext_bh)) {
849 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
850 ext, PTR_ERR(ext_bh));
851 return;
852 }
853 if (AFFS_I(inode)->i_lc) {
854 /* clear linear cache */
855 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
856 if (AFFS_I(inode)->i_lc_size > i) {
857 AFFS_I(inode)->i_lc_size = i;
858 for (; i < AFFS_LC_SIZE; i++)
859 AFFS_I(inode)->i_lc[i] = 0;
860 }
861 /* clear associative cache */
862 for (i = 0; i < AFFS_AC_SIZE; i++)
863 if (AFFS_I(inode)->i_ac[i].ext >= ext)
864 AFFS_I(inode)->i_ac[i].ext = 0;
865 }
866 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
867
868 blkcnt = AFFS_I(inode)->i_blkcnt;
869 i = 0;
870 blk = last_blk;
871 if (inode->i_size) {
872 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
873 blk++;
874 } else
875 AFFS_HEAD(ext_bh)->first_data = 0;
876 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
877 size = AFFS_SB(sb)->s_hashsize;
878 if (size > blkcnt - blk + i)
879 size = blkcnt - blk + i;
880 for (; i < size; i++, blk++) {
881 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
882 AFFS_BLOCK(sb, ext_bh, i) = 0;
883 }
884 AFFS_TAIL(sb, ext_bh)->extension = 0;
885 affs_fix_checksum(sb, ext_bh);
886 mark_buffer_dirty_inode(ext_bh, inode);
887 affs_brelse(ext_bh);
888
889 if (inode->i_size) {
890 AFFS_I(inode)->i_blkcnt = last_blk + 1;
891 AFFS_I(inode)->i_extcnt = ext + 1;
892 if (AFFS_SB(sb)->s_flags & SF_OFS) {
893 struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
894 u32 tmp;
895 if (IS_ERR(bh)) {
896 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
897 ext, PTR_ERR(bh));
898 return;
899 }
900 tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
901 AFFS_DATA_HEAD(bh)->next = 0;
902 affs_adjust_checksum(bh, -tmp);
903 affs_brelse(bh);
904 }
905 } else {
906 AFFS_I(inode)->i_blkcnt = 0;
907 AFFS_I(inode)->i_extcnt = 1;
908 }
909 AFFS_I(inode)->mmu_private = inode->i_size;
910 // unlock cache
911
912 while (ext_key) {
913 ext_bh = affs_bread(sb, ext_key);
914 size = AFFS_SB(sb)->s_hashsize;
915 if (size > blkcnt - blk)
916 size = blkcnt - blk;
917 for (i = 0; i < size; i++, blk++)
918 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
919 affs_free_block(sb, ext_key);
920 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
921 affs_brelse(ext_bh);
922 }
923 affs_free_prealloc(inode);
924 }
925
926 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
927 {
928 struct inode *inode = filp->f_mapping->host;
929 int ret, err;
930
931 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
932 if (err)
933 return err;
934
935 mutex_lock(&inode->i_mutex);
936 ret = write_inode_now(inode, 0);
937 err = sync_blockdev(inode->i_sb->s_bdev);
938 if (!ret)
939 ret = err;
940 mutex_unlock(&inode->i_mutex);
941 return ret;
942 }
Linux Btrfs Development