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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / fs / affs / file.c
blob6e0c9399200e84a74d163e25505d087487a2262d
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 if (block > (sector_t)0x7fffffffUL)
329 BUG();
330
331 if (block >= AFFS_I(inode)->i_blkcnt) {
332 if (block > AFFS_I(inode)->i_blkcnt || !create)
333 goto err_big;
334 } else
335 create = 0;
336
337 //lock cache
338 affs_lock_ext(inode);
339
340 ext = (u32)block / AFFS_SB(sb)->s_hashsize;
341 block -= ext * AFFS_SB(sb)->s_hashsize;
342 ext_bh = affs_get_extblock(inode, ext);
343 if (IS_ERR(ext_bh))
344 goto err_ext;
345 map_bh(bh_result, sb, (sector_t)be32_to_cpu(AFFS_BLOCK(sb, ext_bh, block)));
346
347 if (create) {
348 u32 blocknr = affs_alloc_block(inode, ext_bh->b_blocknr);
349 if (!blocknr)
350 goto err_alloc;
351 set_buffer_new(bh_result);
352 AFFS_I(inode)->mmu_private += AFFS_SB(sb)->s_data_blksize;
353 AFFS_I(inode)->i_blkcnt++;
354
355 /* store new block */
356 if (bh_result->b_blocknr)
357 affs_warning(sb, "get_block", "block already set (%x)", bh_result->b_blocknr);
358 AFFS_BLOCK(sb, ext_bh, block) = cpu_to_be32(blocknr);
359 AFFS_HEAD(ext_bh)->block_count = cpu_to_be32(block + 1);
360 affs_adjust_checksum(ext_bh, blocknr - bh_result->b_blocknr + 1);
361 bh_result->b_blocknr = blocknr;
362
363 if (!block) {
364 /* insert first block into header block */
365 u32 tmp = be32_to_cpu(AFFS_HEAD(ext_bh)->first_data);
366 if (tmp)
367 affs_warning(sb, "get_block", "first block already set (%d)", tmp);
368 AFFS_HEAD(ext_bh)->first_data = cpu_to_be32(blocknr);
369 affs_adjust_checksum(ext_bh, blocknr - tmp);
370 }
371 }
372
373 affs_brelse(ext_bh);
374 //unlock cache
375 affs_unlock_ext(inode);
376 return 0;
377
378 err_big:
379 affs_error(inode->i_sb,"get_block","strange block request %d", block);
380 return -EIO;
381 err_ext:
382 // unlock cache
383 affs_unlock_ext(inode);
384 return PTR_ERR(ext_bh);
385 err_alloc:
386 brelse(ext_bh);
387 clear_buffer_mapped(bh_result);
388 bh_result->b_bdev = NULL;
389 // unlock cache
390 affs_unlock_ext(inode);
391 return -ENOSPC;
392 }
393
394 static int affs_writepage(struct page *page, struct writeback_control *wbc)
395 {
396 return block_write_full_page(page, affs_get_block, wbc);
397 }
398
399 static int affs_readpage(struct file *file, struct page *page)
400 {
401 return block_read_full_page(page, affs_get_block);
402 }
403
404 static int affs_write_begin(struct file *file, struct address_space *mapping,
405 loff_t pos, unsigned len, unsigned flags,
406 struct page **pagep, void **fsdata)
407 {
408 *pagep = NULL;
409 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
410 affs_get_block,
411 &AFFS_I(mapping->host)->mmu_private);
412 }
413
414 static sector_t _affs_bmap(struct address_space *mapping, sector_t block)
415 {
416 return generic_block_bmap(mapping,block,affs_get_block);
417 }
418
419 const struct address_space_operations affs_aops = {
420 .readpage = affs_readpage,
421 .writepage = affs_writepage,
422 .sync_page = block_sync_page,
423 .write_begin = affs_write_begin,
424 .write_end = generic_write_end,
425 .bmap = _affs_bmap
426 };
427
428 static inline struct buffer_head *
429 affs_bread_ino(struct inode *inode, int block, int create)
430 {
431 struct buffer_head *bh, tmp_bh;
432 int err;
433
434 tmp_bh.b_state = 0;
435 err = affs_get_block(inode, block, &tmp_bh, create);
436 if (!err) {
437 bh = affs_bread(inode->i_sb, tmp_bh.b_blocknr);
438 if (bh) {
439 bh->b_state |= tmp_bh.b_state;
440 return bh;
441 }
442 err = -EIO;
443 }
444 return ERR_PTR(err);
445 }
446
447 static inline struct buffer_head *
448 affs_getzeroblk_ino(struct inode *inode, int block)
449 {
450 struct buffer_head *bh, tmp_bh;
451 int err;
452
453 tmp_bh.b_state = 0;
454 err = affs_get_block(inode, block, &tmp_bh, 1);
455 if (!err) {
456 bh = affs_getzeroblk(inode->i_sb, tmp_bh.b_blocknr);
457 if (bh) {
458 bh->b_state |= tmp_bh.b_state;
459 return bh;
460 }
461 err = -EIO;
462 }
463 return ERR_PTR(err);
464 }
465
466 static inline struct buffer_head *
467 affs_getemptyblk_ino(struct inode *inode, int block)
468 {
469 struct buffer_head *bh, tmp_bh;
470 int err;
471
472 tmp_bh.b_state = 0;
473 err = affs_get_block(inode, block, &tmp_bh, 1);
474 if (!err) {
475 bh = affs_getemptyblk(inode->i_sb, tmp_bh.b_blocknr);
476 if (bh) {
477 bh->b_state |= tmp_bh.b_state;
478 return bh;
479 }
480 err = -EIO;
481 }
482 return ERR_PTR(err);
483 }
484
485 static int
486 affs_do_readpage_ofs(struct file *file, struct page *page, unsigned from, unsigned to)
487 {
488 struct inode *inode = page->mapping->host;
489 struct super_block *sb = inode->i_sb;
490 struct buffer_head *bh;
491 char *data;
492 u32 bidx, boff, bsize;
493 u32 tmp;
494
495 pr_debug("AFFS: read_page(%u, %ld, %d, %d)\n", (u32)inode->i_ino, page->index, from, to);
496 if (from > to || to > PAGE_CACHE_SIZE)
497 BUG();
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 if (from + tmp > to || tmp > bsize)
511 BUG();
512 memcpy(data + from, AFFS_DATA(bh) + boff, tmp);
513 affs_brelse(bh);
514 bidx++;
515 from += tmp;
516 boff = 0;
517 }
518 flush_dcache_page(page);
519 kunmap(page);
520 return 0;
521 }
522
523 static int
524 affs_extent_file_ofs(struct inode *inode, u32 newsize)
525 {
526 struct super_block *sb = inode->i_sb;
527 struct buffer_head *bh, *prev_bh;
528 u32 bidx, boff;
529 u32 size, bsize;
530 u32 tmp;
531
532 pr_debug("AFFS: extent_file(%u, %d)\n", (u32)inode->i_ino, newsize);
533 bsize = AFFS_SB(sb)->s_data_blksize;
534 bh = NULL;
535 size = AFFS_I(inode)->mmu_private;
536 bidx = size / bsize;
537 boff = size % bsize;
538 if (boff) {
539 bh = affs_bread_ino(inode, bidx, 0);
540 if (IS_ERR(bh))
541 return PTR_ERR(bh);
542 tmp = min(bsize - boff, newsize - size);
543 if (boff + tmp > bsize || tmp > bsize)
544 BUG();
545 memset(AFFS_DATA(bh) + boff, 0, tmp);
546 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
547 affs_fix_checksum(sb, bh);
548 mark_buffer_dirty_inode(bh, inode);
549 size += tmp;
550 bidx++;
551 } else if (bidx) {
552 bh = affs_bread_ino(inode, bidx - 1, 0);
553 if (IS_ERR(bh))
554 return PTR_ERR(bh);
555 }
556
557 while (size < newsize) {
558 prev_bh = bh;
559 bh = affs_getzeroblk_ino(inode, bidx);
560 if (IS_ERR(bh))
561 goto out;
562 tmp = min(bsize, newsize - size);
563 if (tmp > bsize)
564 BUG();
565 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
566 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
567 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
568 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
569 affs_fix_checksum(sb, bh);
570 bh->b_state &= ~(1UL << BH_New);
571 mark_buffer_dirty_inode(bh, inode);
572 if (prev_bh) {
573 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
574 if (tmp)
575 affs_warning(sb, "extent_file_ofs", "next block already set for %d (%d)", bidx, tmp);
576 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
577 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
578 mark_buffer_dirty_inode(prev_bh, inode);
579 affs_brelse(prev_bh);
580 }
581 size += bsize;
582 bidx++;
583 }
584 affs_brelse(bh);
585 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
586 return 0;
587
588 out:
589 inode->i_size = AFFS_I(inode)->mmu_private = newsize;
590 return PTR_ERR(bh);
591 }
592
593 static int
594 affs_readpage_ofs(struct file *file, struct page *page)
595 {
596 struct inode *inode = page->mapping->host;
597 u32 to;
598 int err;
599
600 pr_debug("AFFS: read_page(%u, %ld)\n", (u32)inode->i_ino, page->index);
601 to = PAGE_CACHE_SIZE;
602 if (((page->index + 1) << PAGE_CACHE_SHIFT) > inode->i_size) {
603 to = inode->i_size & ~PAGE_CACHE_MASK;
604 memset(page_address(page) + to, 0, PAGE_CACHE_SIZE - to);
605 }
606
607 err = affs_do_readpage_ofs(file, page, 0, to);
608 if (!err)
609 SetPageUptodate(page);
610 unlock_page(page);
611 return err;
612 }
613
614 static int affs_write_begin_ofs(struct file *file, struct address_space *mapping,
615 loff_t pos, unsigned len, unsigned flags,
616 struct page **pagep, void **fsdata)
617 {
618 struct inode *inode = mapping->host;
619 struct page *page;
620 pgoff_t index;
621 int err = 0;
622
623 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
624 if (pos > AFFS_I(inode)->mmu_private) {
625 /* XXX: this probably leaves a too-big i_size in case of
626 * failure. Should really be updating i_size at write_end time
627 */
628 err = affs_extent_file_ofs(inode, pos);
629 if (err)
630 return err;
631 }
632
633 index = pos >> PAGE_CACHE_SHIFT;
634 page = __grab_cache_page(mapping, index);
635 if (!page)
636 return -ENOMEM;
637 *pagep = page;
638
639 if (PageUptodate(page))
640 return 0;
641
642 /* XXX: inefficient but safe in the face of short writes */
643 err = affs_do_readpage_ofs(file, page, 0, PAGE_CACHE_SIZE);
644 if (err) {
645 unlock_page(page);
646 page_cache_release(page);
647 }
648 return err;
649 }
650
651 static int affs_write_end_ofs(struct file *file, struct address_space *mapping,
652 loff_t pos, unsigned len, unsigned copied,
653 struct page *page, void *fsdata)
654 {
655 struct inode *inode = mapping->host;
656 struct super_block *sb = inode->i_sb;
657 struct buffer_head *bh, *prev_bh;
658 char *data;
659 u32 bidx, boff, bsize;
660 unsigned from, to;
661 u32 tmp;
662 int written;
663
664 from = pos & (PAGE_CACHE_SIZE - 1);
665 to = pos + len;
666 /*
667 * XXX: not sure if this can handle short copies (len < copied), but
668 * we don't have to, because the page should always be uptodate here,
669 * due to write_begin.
670 */
671
672 pr_debug("AFFS: write_begin(%u, %llu, %llu)\n", (u32)inode->i_ino, (unsigned long long)pos, (unsigned long long)pos + len);
673 bsize = AFFS_SB(sb)->s_data_blksize;
674 data = page_address(page);
675
676 bh = NULL;
677 written = 0;
678 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
679 bidx = tmp / bsize;
680 boff = tmp % bsize;
681 if (boff) {
682 bh = affs_bread_ino(inode, bidx, 0);
683 if (IS_ERR(bh))
684 return PTR_ERR(bh);
685 tmp = min(bsize - boff, to - from);
686 if (boff + tmp > bsize || tmp > bsize)
687 BUG();
688 memcpy(AFFS_DATA(bh) + boff, data + from, tmp);
689 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(be32_to_cpu(AFFS_DATA_HEAD(bh)->size) + tmp);
690 affs_fix_checksum(sb, bh);
691 mark_buffer_dirty_inode(bh, inode);
692 written += tmp;
693 from += tmp;
694 bidx++;
695 } else if (bidx) {
696 bh = affs_bread_ino(inode, bidx - 1, 0);
697 if (IS_ERR(bh))
698 return PTR_ERR(bh);
699 }
700 while (from + bsize <= to) {
701 prev_bh = bh;
702 bh = affs_getemptyblk_ino(inode, bidx);
703 if (IS_ERR(bh))
704 goto out;
705 memcpy(AFFS_DATA(bh), data + from, bsize);
706 if (buffer_new(bh)) {
707 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
708 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
709 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
710 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(bsize);
711 AFFS_DATA_HEAD(bh)->next = 0;
712 bh->b_state &= ~(1UL << BH_New);
713 if (prev_bh) {
714 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
715 if (tmp)
716 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
717 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
718 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
719 mark_buffer_dirty_inode(prev_bh, inode);
720 }
721 }
722 affs_brelse(prev_bh);
723 affs_fix_checksum(sb, bh);
724 mark_buffer_dirty_inode(bh, inode);
725 written += bsize;
726 from += bsize;
727 bidx++;
728 }
729 if (from < to) {
730 prev_bh = bh;
731 bh = affs_bread_ino(inode, bidx, 1);
732 if (IS_ERR(bh))
733 goto out;
734 tmp = min(bsize, to - from);
735 if (tmp > bsize)
736 BUG();
737 memcpy(AFFS_DATA(bh), data + from, tmp);
738 if (buffer_new(bh)) {
739 AFFS_DATA_HEAD(bh)->ptype = cpu_to_be32(T_DATA);
740 AFFS_DATA_HEAD(bh)->key = cpu_to_be32(inode->i_ino);
741 AFFS_DATA_HEAD(bh)->sequence = cpu_to_be32(bidx);
742 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
743 AFFS_DATA_HEAD(bh)->next = 0;
744 bh->b_state &= ~(1UL << BH_New);
745 if (prev_bh) {
746 u32 tmp = be32_to_cpu(AFFS_DATA_HEAD(prev_bh)->next);
747 if (tmp)
748 affs_warning(sb, "commit_write_ofs", "next block already set for %d (%d)", bidx, tmp);
749 AFFS_DATA_HEAD(prev_bh)->next = cpu_to_be32(bh->b_blocknr);
750 affs_adjust_checksum(prev_bh, bh->b_blocknr - tmp);
751 mark_buffer_dirty_inode(prev_bh, inode);
752 }
753 } else if (be32_to_cpu(AFFS_DATA_HEAD(bh)->size) < tmp)
754 AFFS_DATA_HEAD(bh)->size = cpu_to_be32(tmp);
755 affs_brelse(prev_bh);
756 affs_fix_checksum(sb, bh);
757 mark_buffer_dirty_inode(bh, inode);
758 written += tmp;
759 from += tmp;
760 bidx++;
761 }
762 SetPageUptodate(page);
763
764 done:
765 affs_brelse(bh);
766 tmp = (page->index << PAGE_CACHE_SHIFT) + from;
767 if (tmp > inode->i_size)
768 inode->i_size = AFFS_I(inode)->mmu_private = tmp;
769
770 unlock_page(page);
771 page_cache_release(page);
772
773 return written;
774
775 out:
776 bh = prev_bh;
777 if (!written)
778 written = PTR_ERR(bh);
779 goto done;
780 }
781
782 const struct address_space_operations affs_aops_ofs = {
783 .readpage = affs_readpage_ofs,
784 //.writepage = affs_writepage_ofs,
785 //.sync_page = affs_sync_page_ofs,
786 .write_begin = affs_write_begin_ofs,
787 .write_end = affs_write_end_ofs
788 };
789
790 /* Free any preallocated blocks. */
791
792 void
793 affs_free_prealloc(struct inode *inode)
794 {
795 struct super_block *sb = inode->i_sb;
796
797 pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
798
799 while (AFFS_I(inode)->i_pa_cnt) {
800 AFFS_I(inode)->i_pa_cnt--;
801 affs_free_block(sb, ++AFFS_I(inode)->i_lastalloc);
802 }
803 }
804
805 /* Truncate (or enlarge) a file to the requested size. */
806
807 void
808 affs_truncate(struct inode *inode)
809 {
810 struct super_block *sb = inode->i_sb;
811 u32 ext, ext_key;
812 u32 last_blk, blkcnt, blk;
813 u32 size;
814 struct buffer_head *ext_bh;
815 int i;
816
817 pr_debug("AFFS: truncate(inode=%d, oldsize=%u, newsize=%u)\n",
818 (u32)inode->i_ino, (u32)AFFS_I(inode)->mmu_private, (u32)inode->i_size);
819
820 last_blk = 0;
821 ext = 0;
822 if (inode->i_size) {
823 last_blk = ((u32)inode->i_size - 1) / AFFS_SB(sb)->s_data_blksize;
824 ext = last_blk / AFFS_SB(sb)->s_hashsize;
825 }
826
827 if (inode->i_size > AFFS_I(inode)->mmu_private) {
828 struct address_space *mapping = inode->i_mapping;
829 struct page *page;
830 void *fsdata;
831 u32 size = inode->i_size;
832 int res;
833
834 res = mapping->a_ops->write_begin(NULL, mapping, size, 0, 0, &page, &fsdata);
835 if (!res)
836 res = mapping->a_ops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
837 mark_inode_dirty(inode);
838 return;
839 } else if (inode->i_size == AFFS_I(inode)->mmu_private)
840 return;
841
842 // lock cache
843 ext_bh = affs_get_extblock(inode, ext);
844 if (IS_ERR(ext_bh)) {
845 affs_warning(sb, "truncate", "unexpected read error for ext block %u (%d)",
846 ext, PTR_ERR(ext_bh));
847 return;
848 }
849 if (AFFS_I(inode)->i_lc) {
850 /* clear linear cache */
851 i = (ext + 1) >> AFFS_I(inode)->i_lc_shift;
852 if (AFFS_I(inode)->i_lc_size > i) {
853 AFFS_I(inode)->i_lc_size = i;
854 for (; i < AFFS_LC_SIZE; i++)
855 AFFS_I(inode)->i_lc[i] = 0;
856 }
857 /* clear associative cache */
858 for (i = 0; i < AFFS_AC_SIZE; i++)
859 if (AFFS_I(inode)->i_ac[i].ext >= ext)
860 AFFS_I(inode)->i_ac[i].ext = 0;
861 }
862 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
863
864 blkcnt = AFFS_I(inode)->i_blkcnt;
865 i = 0;
866 blk = last_blk;
867 if (inode->i_size) {
868 i = last_blk % AFFS_SB(sb)->s_hashsize + 1;
869 blk++;
870 } else
871 AFFS_HEAD(ext_bh)->first_data = 0;
872 size = AFFS_SB(sb)->s_hashsize;
873 if (size > blkcnt - blk + i)
874 size = blkcnt - blk + i;
875 for (; i < size; i++, blk++) {
876 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
877 AFFS_BLOCK(sb, ext_bh, i) = 0;
878 }
879 AFFS_TAIL(sb, ext_bh)->extension = 0;
880 affs_fix_checksum(sb, ext_bh);
881 mark_buffer_dirty_inode(ext_bh, inode);
882 affs_brelse(ext_bh);
883
884 if (inode->i_size) {
885 AFFS_I(inode)->i_blkcnt = last_blk + 1;
886 AFFS_I(inode)->i_extcnt = ext + 1;
887 if (AFFS_SB(sb)->s_flags & SF_OFS) {
888 struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
889 u32 tmp;
890 if (IS_ERR(ext_bh)) {
891 affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
892 ext, PTR_ERR(ext_bh));
893 return;
894 }
895 tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);
896 AFFS_DATA_HEAD(bh)->next = 0;
897 affs_adjust_checksum(bh, -tmp);
898 affs_brelse(bh);
899 }
900 } else {
901 AFFS_I(inode)->i_blkcnt = 0;
902 AFFS_I(inode)->i_extcnt = 1;
903 }
904 AFFS_I(inode)->mmu_private = inode->i_size;
905 // unlock cache
906
907 while (ext_key) {
908 ext_bh = affs_bread(sb, ext_key);
909 size = AFFS_SB(sb)->s_hashsize;
910 if (size > blkcnt - blk)
911 size = blkcnt - blk;
912 for (i = 0; i < size; i++, blk++)
913 affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
914 affs_free_block(sb, ext_key);
915 ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
916 affs_brelse(ext_bh);
917 }
918 affs_free_prealloc(inode);
919 }
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