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[deliverable/linux.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 <linux/uio.h>
16 #include "affs.h"
17
18 static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);
19
20 static int
21 affs_file_open(struct inode *inode, struct file *filp)
22 {
23 pr_debug("open(%lu,%d)\n",
24 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
25 atomic_inc(&AFFS_I(inode)->i_opencnt);
26 return 0;
27 }
28
29 static int
30 affs_file_release(struct inode *inode, struct file *filp)
31 {
32 pr_debug("release(%lu, %d)\n",
33 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
34
35 if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
36 inode_lock(inode);
37 if (inode->i_size != AFFS_I(inode)->mmu_private)
38 affs_truncate(inode);
39 affs_free_prealloc(inode);
40 inode_unlock(inode);
41 }
42
43 return 0;
44 }
45
46 static int
47 affs_grow_extcache(struct inode *inode, u32 lc_idx)
48 {
49 struct super_block *sb = inode->i_sb;
50 struct buffer_head *bh;
51 u32 lc_max;
52 int i, j, key;
53
54 if (!AFFS_I(inode)->i_lc) {
55 char *ptr = (char *)get_zeroed_page(GFP_NOFS);
56 if (!ptr)
57 return -ENOMEM;
58 AFFS_I(inode)->i_lc = (u32 *)ptr;
59 AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
60 }
61
62 lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;
63
64 if (AFFS_I(inode)->i_extcnt > lc_max) {
65 u32 lc_shift, lc_mask, tmp, off;
66
67 /* need to recalculate linear cache, start from old size */
68 lc_shift = AFFS_I(inode)->i_lc_shift;
69 tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
70 for (; tmp; tmp >>= 1)
71 lc_shift++;
72 lc_mask = (1 << lc_shift) - 1;
73
74 /* fix idx and old size to new shift */
75 lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
76 AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
77
78 /* first shrink old cache to make more space */
79 off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
80 for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
81 AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];
82
83 AFFS_I(inode)->i_lc_shift = lc_shift;
84 AFFS_I(inode)->i_lc_mask = lc_mask;
85 }
86
87 /* fill cache to the needed index */
88 i = AFFS_I(inode)->i_lc_size;
89 AFFS_I(inode)->i_lc_size = lc_idx + 1;
90 for (; i <= lc_idx; i++) {
91 if (!i) {
92 AFFS_I(inode)->i_lc[0] = inode->i_ino;
93 continue;
94 }
95 key = AFFS_I(inode)->i_lc[i - 1];
96 j = AFFS_I(inode)->i_lc_mask + 1;
97 // unlock cache
98 for (; j > 0; j--) {
99 bh = affs_bread(sb, key);
100 if (!bh)
101 goto err;
102 key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
103 affs_brelse(bh);
104 }
105 // lock cache
106 AFFS_I(inode)->i_lc[i] = key;
107 }
108
109 return 0;
110
111 err:
112 // lock cache
113 return -EIO;
114 }
115
116 static struct buffer_head *
117 affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
118 {
119 struct super_block *sb = inode->i_sb;
120 struct buffer_head *new_bh;
121 u32 blocknr, tmp;
122
123 blocknr = affs_alloc_block(inode, bh->b_blocknr);
124 if (!blocknr)
125 return ERR_PTR(-ENOSPC);
126
127 new_bh = affs_getzeroblk(sb, blocknr);
128 if (!new_bh) {
129 affs_free_block(sb, blocknr);
130 return ERR_PTR(-EIO);
131 }
132
133 AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
134 AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
135 AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
136 AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
137 affs_fix_checksum(sb, new_bh);
138
139 mark_buffer_dirty_inode(new_bh, inode);
140
141 tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
142 if (tmp)
143 affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
144 AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
145 affs_adjust_checksum(bh, blocknr - tmp);
146 mark_buffer_dirty_inode(bh, inode);
147
148 AFFS_I(inode)->i_extcnt++;
149 mark_inode_dirty(inode);
150
151 return new_bh;
152 }
153
154 static inline struct buffer_head *
155 affs_get_extblock(struct inode *inode, u32 ext)
156 {
157 /* inline the simplest case: same extended block as last time */
158 struct buffer_head *bh = AFFS_I(inode)->i_ext_bh;
159 if (ext == AFFS_I(inode)->i_ext_last)
160 get_bh(bh);
161 else
162 /* we have to do more (not inlined) */
163 bh = affs_get_extblock_slow(inode, ext);
164
165 return bh;
166 }
167
168 static struct buffer_head *
169 affs_get_extblock_slow(struct inode *inode, u32 ext)
170 {
171 struct super_block *sb = inode->i_sb;
172 struct buffer_head *bh;
173 u32 ext_key;
174 u32 lc_idx, lc_off, ac_idx;
175 u32 tmp, idx;
176
177 if (ext == AFFS_I(inode)->i_ext_last + 1) {
178 /* read the next extended block from the current one */
179 bh = AFFS_I(inode)->i_ext_bh;
180 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
181 if (ext < AFFS_I(inode)->i_extcnt)
182 goto read_ext;
183 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
184 bh = affs_alloc_extblock(inode, bh, ext);
185 if (IS_ERR(bh))
186 return bh;
187 goto store_ext;
188 }
189
190 if (ext == 0) {
191 /* we seek back to the file header block */
192 ext_key = inode->i_ino;
193 goto read_ext;
194 }
195
196 if (ext >= AFFS_I(inode)->i_extcnt) {
197 struct buffer_head *prev_bh;
198
199 /* allocate a new extended block */
200 BUG_ON(ext > AFFS_I(inode)->i_extcnt);
201
202 /* get previous extended block */
203 prev_bh = affs_get_extblock(inode, ext - 1);
204 if (IS_ERR(prev_bh))
205 return prev_bh;
206 bh = affs_alloc_extblock(inode, prev_bh, ext);
207 affs_brelse(prev_bh);
208 if (IS_ERR(bh))
209 return bh;
210 goto store_ext;
211 }
212
213 again:
214 /* check if there is an extended cache and whether it's large enough */
215 lc_idx = ext >> AFFS_I(inode)->i_lc_shift;
216 lc_off = ext & AFFS_I(inode)->i_lc_mask;
217
218 if (lc_idx >= AFFS_I(inode)->i_lc_size) {
219 int err;
220
221 err = affs_grow_extcache(inode, lc_idx);
222 if (err)
223 return ERR_PTR(err);
224 goto again;
225 }
226
227 /* every n'th key we find in the linear cache */
228 if (!lc_off) {
229 ext_key = AFFS_I(inode)->i_lc[lc_idx];
230 goto read_ext;
231 }
232
233 /* maybe it's still in the associative cache */
234 ac_idx = (ext - lc_idx - 1) & AFFS_AC_MASK;
235 if (AFFS_I(inode)->i_ac[ac_idx].ext == ext) {
236 ext_key = AFFS_I(inode)->i_ac[ac_idx].key;
237 goto read_ext;
238 }
239
240 /* try to find one of the previous extended blocks */
241 tmp = ext;
242 idx = ac_idx;
243 while (--tmp, --lc_off > 0) {
244 idx = (idx - 1) & AFFS_AC_MASK;
245 if (AFFS_I(inode)->i_ac[idx].ext == tmp) {
246 ext_key = AFFS_I(inode)->i_ac[idx].key;
247 goto find_ext;
248 }
249 }
250
251 /* fall back to the linear cache */
252 ext_key = AFFS_I(inode)->i_lc[lc_idx];
253 find_ext:
254 /* read all extended blocks until we find the one we need */
255 //unlock cache
256 do {
257 bh = affs_bread(sb, ext_key);
258 if (!bh)
259 goto err_bread;
260 ext_key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
261 affs_brelse(bh);
262 tmp++;
263 } while (tmp < ext);
264 //lock cache
265
266 /* store it in the associative cache */
267 // recalculate ac_idx?
268 AFFS_I(inode)->i_ac[ac_idx].ext = ext;
269 AFFS_I(inode)->i_ac[ac_idx].key = ext_key;
270
271 read_ext:
272 /* finally read the right extended block */
273 //unlock cache
274 bh = affs_bread(sb, ext_key);
275 if (!bh)
276 goto err_bread;
277 //lock cache
278
279 store_ext:
280 /* release old cached extended block and store the new one */
281 affs_brelse(AFFS_I(inode)->i_ext_bh);
282 AFFS_I(inode)->i_ext_last = ext;
283 AFFS_I(inode)->i_ext_bh = bh;
284 get_bh(bh);
285
286 return bh;
287
288 err_bread:
289 affs_brelse(bh);
290 return ERR_PTR(-EIO);
291 }
292
293 static int
294 affs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh_result, int create)
295 {
296 struct super_block *sb = inode->i_sb;
297 struct buffer_head *ext_bh;
298 u32 ext;
299
300 pr_debug("%s(%lu, %llu)\n", __func__, inode->i_ino,
301 (unsigned long long)block);
302
303 BUG_ON(block > (sector_t)0x7fffffffUL);
304
305 if (block >= AFFS_I(inode)->i_blkcnt) {
306 if (block > AFFS_I(inode)->i_blkcnt || !create)
307 goto err_big;
308 } else
309 create = 0;
310
311 //lock cache
312 affs_lock_ext(inode);
313
314 ext = (u32)block / AFFS_SB(sb)->s_hashsize;
315 block -= ext * AFFS_SB(sb)->s_hashsize;
316 ext_bh = affs_get_extblock(inode, ext);
317 if (IS_ERR(ext_bh))
318 goto err_ext;
319 map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
320
321 if (create) {
322 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
323 if (!blocknr)
324 goto err_alloc;
325 set_buffer_new(bh_result);
326 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
327 AFFS_I(inode)->i_blkcnt++;
328
329 /* store new block */
330 if (bh_result->b_blocknr)
331 affs_warning(sb, "get_block",
332 "block already set (%llx)",
333 (unsigned long long)bh_result->b_blocknr);
334 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
335 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
336 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
337 bh_result->b_blocknr = blocknr;
338
339 if (!block) {
340 /* insert first block into header block */
341 u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
342 if (tmp)
343 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
344 AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
345 affs_adjust_checksum(ext_bh, blocknr - tmp);
346 }
347 }
348
349 affs_brelse(ext_bh);
350 //unlock cache
351 affs_unlock_ext(inode);
352 return 0;
353
354 err_big:
355 affs_error(inode->i_sb, "get_block", "strange block request %llu",
356 (unsigned long long)block);
357 return -EIO;
358 err_ext:
359 // unlock cache
360 affs_unlock_ext(inode);
361 return PTR_ERR(ext_bh);
362 err_alloc:
363 brelse(ext_bh);
364 clear_buffer_mapped(bh_result);
365 bh_result->b_bdev = NULL;
366 // unlock cache
367 affs_unlock_ext(inode);
368 return -ENOSPC;
369 }
370
371 static int affs_writepage(struct page *page, struct writeback_control *wbc)
372 {
373 return block_write_full_page(page, affs_get_block, wbc);
374 }
375
376 static int affs_readpage(struct file *file, struct page *page)
377 {
378 return block_read_full_page(page, affs_get_block);
379 }
380
381 static void affs_write_failed(struct address_space *mapping, loff_t to)
382 {
383 struct inode *inode = mapping->host;
384
385 if (to > inode->i_size) {
386 truncate_pagecache(inode, inode->i_size);
387 affs_truncate(inode);
388 }
389 }
390
391 static ssize_t
392 affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
393 {
394 struct file *file = iocb->ki_filp;
395 struct address_space *mapping = file->f_mapping;
396 struct inode *inode = mapping->host;
397 size_t count = iov_iter_count(iter);
398 ssize_t ret;
399
400 if (iov_iter_rw(iter) == WRITE) {
401 loff_t size = offset + count;
402
403 if (AFFS_I(inode)->mmu_private < size)
404 return 0;
405 }
406
407 ret = blockdev_direct_IO(iocb, inode, iter, offset, affs_get_block);
408 if (ret < 0 && iov_iter_rw(iter) == WRITE)
409 affs_write_failed(mapping, offset + count);
410 return ret;
411 }
412
413 static int affs_write_begin(struct file *file, struct address_space *mapping,
414 loff_t pos, unsigned len, unsigned flags,
415 struct page **pagep, void **fsdata)
416 {
417 int ret;
418
419 *pagep = NULL;
420 ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
421 affs_get_block,
422 &AFFS_I(mapping->host)->mmu_private);
423 if (unlikely(ret))
424 affs_write_failed(mapping, pos + len);
425
426 return ret;
427 }
428
429 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
430 {
431 return generic_block_bmap(mapping,block,affs_get_block);
432 }
433
434 const struct address_space_operations affs_aops = {
435 .readpage = affs_readpage,
436 .writepage = affs_writepage,
437 .write_begin = affs_write_begin,
438 .write_end = generic_write_end,
439 .direct_IO = affs_direct_IO,
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 page *page, 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 unsigned pos = 0;
508 u32 bidx, boff, bsize;
509 u32 tmp;
510
511 pr_debug("%s(%lu, %ld, 0, %d)\n", __func__, inode->i_ino,
512 page->index, to);
513 BUG_ON(to > PAGE_SIZE);
514 bsize = AFFS_SB(sb)->s_data_blksize;
515 tmp = page->index << PAGE_SHIFT;
516 bidx = tmp / bsize;
517 boff = tmp % bsize;
518
519 while (pos < 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 - pos);
524 BUG_ON(pos + tmp > to || tmp > bsize);
525 data = kmap_atomic(page);
526 memcpy(data + pos, AFFS_DATA(bh) + boff, tmp);
527 kunmap_atomic(data);
528 affs_brelse(bh);
529 bidx++;
530 pos += tmp;
531 boff = 0;
532 }
533 flush_dcache_page(page);
534 return 0;
535 }
536
537 static int
538 affs_extent_file_ofs(struct inode *inode, u32 newsize)
539 {
540 struct super_block *sb = inode->i_sb;
541 struct buffer_head *bh, *prev_bh;
542 u32 bidx, boff;
543 u32 size, bsize;
544 u32 tmp;
545
546 pr_debug("%s(%lu, %d)\n", __func__, inode->i_ino, newsize);
547 bsize = AFFS_SB(sb)->s_data_blksize;
548 bh = NULL;
549 size = AFFS_I(inode)->mmu_private;
550 bidx = size / bsize;
551 boff = size % bsize;
552 if (boff) {
553 bh = affs_bread_ino(inode, bidx, 0);
554 if (IS_ERR(bh))
555 return PTR_ERR(bh);
556 tmp = min(bsize - boff, newsize - size);
557 BUG_ON(boff + tmp > bsize || tmp > bsize);
558 memset(AFFS_DATA(bh) + boff, 0, tmp);
559 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
560 affs_fix_checksum(sb, bh);
561 mark_buffer_dirty_inode(bh, inode);
562 size += tmp;
563 bidx++;
564 } else if (bidx) {
565 bh = affs_bread_ino(inode, bidx - 1, 0);
566 if (IS_ERR(bh))
567 return PTR_ERR(bh);
568 }
569
570 while (size < newsize) {
571 prev_bh = bh;
572 bh = affs_getzeroblk_ino(inode, bidx);
573 if (IS_ERR(bh))
574 goto out;
575 tmp = min(bsize, newsize - size);
576 BUG_ON(tmp > bsize);
577 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
578 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
579 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
580 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
581 affs_fix_checksum(sb, bh);
582 bh->b_state &= ~(1UL << BH_New);
583 mark_buffer_dirty_inode(bh, inode);
584 if (prev_bh) {
585 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
586
587 if (tmp_next)
588 affs_warning(sb, "extent_file_ofs",
589 "next block already set for %d (%d)",
590 bidx, tmp_next);
591 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
592 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
593 mark_buffer_dirty_inode(prev_bh, inode);
594 affs_brelse(prev_bh);
595 }
596 size += bsize;
597 bidx++;
598 }
599 affs_brelse(bh);
600 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
601 return 0;
602
603 out:
604 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
605 return PTR_ERR(bh);
606 }
607
608 static int
609 affs_readpage_ofs(struct file *file, struct page *page)
610 {
611 struct inode *inode = page->mapping->host;
612 u32 to;
613 int err;
614
615 pr_debug("%s(%lu, %ld)\n", __func__, inode->i_ino, page->index);
616 to = PAGE_SIZE;
617 if (((page->index + 1) << PAGE_SHIFT) > inode->i_size) {
618 to = inode->i_size & ~PAGE_MASK;
619 memset(page_address(page) + to, 0, PAGE_SIZE - to);
620 }
621
622 err = affs_do_readpage_ofs(page, to);
623 if (!err)
624 SetPageUptodate(page);
625 unlock_page(page);
626 return err;
627 }
628
629 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
630 loff_t pos, unsigned len, unsigned flags,
631 struct page **pagep, void **fsdata)
632 {
633 struct inode *inode = mapping->host;
634 struct page *page;
635 pgoff_t index;
636 int err = 0;
637
638 pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
639 pos + len);
640 if (pos > AFFS_I(inode)->mmu_private) {
641 /* XXX: this probably leaves a too-big i_size in case of
642 * failure. Should really be updating i_size at write_end time
643 */
644 err = affs_extent_file_ofs(inode, pos);
645 if (err)
646 return err;
647 }
648
649 index = pos >> PAGE_SHIFT;
650 page = grab_cache_page_write_begin(mapping, index, flags);
651 if (!page)
652 return -ENOMEM;
653 *pagep = page;
654
655 if (PageUptodate(page))
656 return 0;
657
658 /* XXX: inefficient but safe in the face of short writes */
659 err = affs_do_readpage_ofs(page, PAGE_SIZE);
660 if (err) {
661 unlock_page(page);
662 put_page(page);
663 }
664 return err;
665 }
666
667 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
668 loff_t pos, unsigned len, unsigned copied,
669 struct page *page, void *fsdata)
670 {
671 struct inode *inode = mapping->host;
672 struct super_block *sb = inode->i_sb;
673 struct buffer_head *bh, *prev_bh;
674 char *data;
675 u32 bidx, boff, bsize;
676 unsigned from, to;
677 u32 tmp;
678 int written;
679
680 from = pos & (PAGE_SIZE - 1);
681 to = pos + len;
682 /*
683 * XXX: not sure if this can handle short copies (len < copied), but
684 * we don't have to, because the page should always be uptodate here,
685 * due to write_begin.
686 */
687
688 pr_debug("%s(%lu, %llu, %llu)\n", __func__, inode->i_ino, pos,
689 pos + len);
690 bsize = AFFS_SB(sb)->s_data_blksize;
691 data = page_address(page);
692
693 bh = NULL;
694 written = 0;
695 tmp = (page->index << PAGE_SHIFT) + from;
696 bidx = tmp / bsize;
697 boff = tmp % bsize;
698 if (boff) {
699 bh = affs_bread_ino(inode, bidx, 0);
700 if (IS_ERR(bh)) {
701 written = PTR_ERR(bh);
702 goto err_first_bh;
703 }
704 tmp = min(bsize - boff, to - from);
705 BUG_ON(boff + tmp > bsize || tmp > bsize);
706 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
707 be32_add_cpu(&AFFS_DATA_HEAD(bh)->size, tmp);
708 affs_fix_checksum(sb, bh);
709 mark_buffer_dirty_inode(bh, inode);
710 written += tmp;
711 from += tmp;
712 bidx++;
713 } else if (bidx) {
714 bh = affs_bread_ino(inode, bidx - 1, 0);
715 if (IS_ERR(bh)) {
716 written = PTR_ERR(bh);
717 goto err_first_bh;
718 }
719 }
720 while (from + bsize <= to) {
721 prev_bh = bh;
722 bh = affs_getemptyblk_ino(inode, bidx);
723 if (IS_ERR(bh))
724 goto err_bh;
725 memcpy(AFFS_DATA(bh), data + from, bsize);
726 if (buffer_new(bh)) {
727 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
728 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
729 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
730 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
731 AFFS_DATA_HEAD(bh)->next = 0;
732 bh->b_state &= ~(1UL << BH_New);
733 if (prev_bh) {
734 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
735
736 if (tmp_next)
737 affs_warning(sb, "commit_write_ofs",
738 "next block already set for %d (%d)",
739 bidx, tmp_next);
740 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
741 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
742 mark_buffer_dirty_inode(prev_bh, inode);
743 }
744 }
745 affs_brelse(prev_bh);
746 affs_fix_checksum(sb, bh);
747 mark_buffer_dirty_inode(bh, inode);
748 written += bsize;
749 from += bsize;
750 bidx++;
751 }
752 if (from < to) {
753 prev_bh = bh;
754 bh = affs_bread_ino(inode, bidx, 1);
755 if (IS_ERR(bh))
756 goto err_bh;
757 tmp = min(bsize, to - from);
758 BUG_ON(tmp > bsize);
759 memcpy(AFFS_DATA(bh), data + from, tmp);
760 if (buffer_new(bh)) {
761 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
762 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
763 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
764 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
765 AFFS_DATA_HEAD(bh)->next = 0;
766 bh->b_state &= ~(1UL << BH_New);
767 if (prev_bh) {
768 u32 tmp_next = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
769
770 if (tmp_next)
771 affs_warning(sb, "commit_write_ofs",
772 "next block already set for %d (%d)",
773 bidx, tmp_next);
774 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
775 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp_next);
776 mark_buffer_dirty_inode(prev_bh, inode);
777 }
778 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
779 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
780 affs_brelse(prev_bh);
781 affs_fix_checksum(sb, bh);
782 mark_buffer_dirty_inode(bh, inode);
783 written += tmp;
784 from += tmp;
785 bidx++;
786 }
787 SetPageUptodate(page);
788
789 done:
790 affs_brelse(bh);
791 tmp = (page->index << PAGE_SHIFT) + from;
792 if (tmp > inode->i_size)
793 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
794
795 err_first_bh:
796 unlock_page(page);
797 put_page(page);
798
799 return written;
800
801 err_bh:
802 bh = prev_bh;
803 if (!written)
804 written = PTR_ERR(bh);
805 goto done;
806 }
807
808 const struct address_space_operations affs_aops_ofs = {
809 .readpage = affs_readpage_ofs,
810 //.writepage = affs_writepage_ofs,
811 .write_begin = affs_write_begin_ofs,
812 .write_end = affs_write_end_ofs
813 };
814
815 /* Free any preallocated blocks. */
816
817 void
818 affs_free_prealloc(struct inode *inode)
819 {
820 struct super_block *sb = inode->i_sb;
821
822 pr_debug("free_prealloc(ino=%lu)\n", inode->i_ino);
823
824 while (AFFS_I(inode)->i_pa_cnt) {
825 AFFS_I(inode)->i_pa_cnt--;
826 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
827 }
828 }
829
830 /* Truncate (or enlarge) a file to the requested size. */
831
832 void
833 affs_truncate(struct inode *inode)
834 {
835 struct super_block *sb = inode->i_sb;
836 u32 ext, ext_key;
837 u32 last_blk, blkcnt, blk;
838 u32 size;
839 struct buffer_head *ext_bh;
840 int i;
841
842 pr_debug("truncate(inode=%lu, oldsize=%llu, newsize=%llu)\n",
843 inode->i_ino, AFFS_I(inode)->mmu_private, inode->i_size);
844
845 last_blk = 0;
846 ext = 0;
847 if (inode->i_size) {
848 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
849 ext = last_blk / AFFS_SB(sb)->s_hashsize;
850 }
851
852 if (inode->i_size > AFFS_I(inode)->mmu_private) {
853 struct address_space *mapping = inode->i_mapping;
854 struct page *page;
855 void *fsdata;
856 loff_t isize = inode->i_size;
857 int res;
858
859 res = mapping->a_ops->write_begin(NULL, mapping, isize, 0, 0, &page, &fsdata);
860 if (!res)
861 res = mapping->a_ops->write_end(NULL, mapping, isize, 0, 0, page, fsdata);
862 else
863 inode->i_size = AFFS_I(inode)->mmu_private;
864 mark_inode_dirty(inode);
865 return;
866 } else if (inode->i_size == AFFS_I(inode)->mmu_private)
867 return;
868
869 // lock cache
870 ext_bh = affs_get_extblock(inode, ext);
871 if (IS_ERR(ext_bh)) {
872 affs_warning(sb, "truncate",
873 "unexpected read error for ext block %u (%ld)",
874 ext, PTR_ERR(ext_bh));
875 return;
876 }
877 if (AFFS_I(inode)->i_lc) {
878 /* clear linear cache */
879 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
880 if (AFFS_I(inode)->i_lc_size > i) {
881 AFFS_I(inode)->i_lc_size = i;
882 for (; i < AFFS_LC_SIZE; i++)
883 AFFS_I(inode)->i_lc[i] = 0;
884 }
885 /* clear associative cache */
886 for (i = 0; i < AFFS_AC_SIZE; i++)
887 if (AFFS_I(inode)->i_ac[i].ext >= ext)
888 AFFS_I(inode)->i_ac[i].ext = 0;
889 }
890 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
891
892 blkcnt = AFFS_I(inode)->i_blkcnt;
893 i = 0;
894 blk = last_blk;
895 if (inode->i_size) {
896 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
897 blk++;
898 } else
899 AFFS_HEAD(ext_bh)->first_data = 0;
900 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(i);
901 size = AFFS_SB(sb)->s_hashsize;
902 if (size > blkcnt - blk + i)
903 size = blkcnt - blk + i;
904 for (; i < size; i++, blk++) {
905 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
906 AFFS_BLOCK(sb, ext_bh, i) = 0;
907 }
908 AFFS_TAIL(sb, ext_bh)->extension = 0;
909 affs_fix_checksum(sb, ext_bh);
910 mark_buffer_dirty_inode(ext_bh, inode);
911 affs_brelse(ext_bh);
912
913 if (inode->i_size) {
914 AFFS_I(inode)->i_blkcnt = last_blk + 1;
915 AFFS_I(inode)->i_extcnt = ext + 1;
916 if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS)) {
917 struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
918 u32 tmp;
919 if (IS_ERR(bh)) {
920 affs_warning(sb, "truncate",
921 "unexpected read error for last block %u (%ld)",
922 ext, PTR_ERR(bh));
923 return;
924 }
925 tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
926 AFFS_DATA_HEAD(bh)->next = 0;
927 affs_adjust_checksum(bh, -tmp);
928 affs_brelse(bh);
929 }
930 } else {
931 AFFS_I(inode)->i_blkcnt = 0;
932 AFFS_I(inode)->i_extcnt = 1;
933 }
934 AFFS_I(inode)->mmu_private = inode->i_size;
935 // unlock cache
936
937 while (ext_key) {
938 ext_bh = affs_bread(sb, ext_key);
939 size = AFFS_SB(sb)->s_hashsize;
940 if (size > blkcnt - blk)
941 size = blkcnt - blk;
942 for (i = 0; i < size; i++, blk++)
943 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
944 affs_free_block(sb, ext_key);
945 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
946 affs_brelse(ext_bh);
947 }
948 affs_free_prealloc(inode);
949 }
950
951 int affs_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
952 {
953 struct inode *inode = filp->f_mapping->host;
954 int ret, err;
955
956 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
957 if (err)
958 return err;
959
960 inode_lock(inode);
961 ret = write_inode_now(inode, 0);
962 err = sync_blockdev(inode->i_sb->s_bdev);
963 if (!ret)
964 ret = err;
965 inode_unlock(inode);
966 return ret;
967 }
968 const struct file_operations affs_file_operations = {
969 .llseek = generic_file_llseek,
970 .read_iter = generic_file_read_iter,
971 .write_iter = generic_file_write_iter,
972 .mmap = generic_file_mmap,
973 .open = affs_file_open,
974 .release = affs_file_release,
975 .fsync = affs_file_fsync,
976 .splice_read = generic_file_splice_read,
977 };
978
979 const struct inode_operations affs_file_inode_operations = {
980 .setattr = affs_notify_change,
981 };
Linux kernel - Deliverables
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