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[davej-history.git] / fs / affs / file.c
blobde0808b9e104c4942513a94f2767fa01d48b1938
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 #define DEBUG 0
16 #include <asm/div64.h>
17 #include <asm/uaccess.h>
18 #include <asm/system.h>
19 #include <linux/sched.h>
20 #include <linux/affs_fs.h>
21 #include <linux/fcntl.h>
22 #include <linux/kernel.h>
23 #include <linux/errno.h>
24 #include <linux/malloc.h>
25 #include <linux/stat.h>
26 #include <linux/locks.h>
27 #include <linux/smp_lock.h>
28 #include <linux/dirent.h>
29 #include <linux/fs.h>
30 #include <linux/amigaffs.h>
31 #include <linux/mm.h>
32 #include <linux/pagemap.h>
33
34 #define MIN(a,b) (((a)<(b))?(a):(b))
35 #define MAX(a,b) (((a)>(b))?(a):(b))
36
37 #if PAGE_SIZE < 4096
38 #error PAGE_SIZE must be at least 4096
39 #endif
40
41 static struct buffer_head *affs_getblock(struct inode *inode, s32 block);
42 static ssize_t affs_file_read_ofs(struct file *filp, char *buf, size_t count, loff_t *ppos);
43 static ssize_t affs_file_write(struct file *filp, const char *buf, size_t count, loff_t *ppos);
44 static ssize_t affs_file_write_ofs(struct file *filp, const char *buf, size_t cnt, loff_t *ppos);
45 static int alloc_ext_cache(struct inode *inode);
46
47 struct file_operations affs_file_operations = {
48 read: generic_file_read,
49 write: affs_file_write,
50 mmap: generic_file_mmap,
51 fsync: file_fsync,
52 };
53
54 struct inode_operations affs_file_inode_operations = {
55 truncate: affs_truncate,
56 setattr: affs_notify_change,
57 };
58
59 struct file_operations affs_file_operations_ofs = {
60 read: affs_file_read_ofs,
61 write: affs_file_write_ofs,
62 fsync: file_fsync,
63 };
64
65 #define AFFS_ISINDEX(x) ((x < 129) || \
66 (x < 512 && (x & 1) == 0) || \
67 (x < 1024 && (x & 3) == 0) || \
68 (x < 2048 && (x & 15) == 0) || \
69 (x < 4096 && (x & 63) == 0) || \
70 (x < 20480 && (x & 255) == 0) || \
71 (x < 36864 && (x & 511) == 0))
72
73 /* The keys of the extension blocks are stored in a 512-entry
74 * deep cache. In order to save memory, not every key of later
75 * extension blocks is stored - the larger the file gets, the
76 * bigger the holes in between.
77 */
78
79 static int
80 seqnum_to_index(int seqnum)
81 {
82 /* All of the first 127 keys are stored */
83 if (seqnum < 128)
84 return seqnum;
85 seqnum -= 128;
86
87 /* Of the next 384 keys, every 2nd is kept */
88 if (seqnum < (192 * 2))
89 return 128 + (seqnum >> 1);
90 seqnum -= 192 * 2;
91
92 /* Every 4th of the next 512 */
93 if (seqnum < (128 * 4))
94 return 128 + 192 + (seqnum >> 2);
95 seqnum -= 128 * 4;
96
97 /* Every 16th of the next 1024 */
98 if (seqnum < (64 * 16))
99 return 128 + 192 + 128 + (seqnum >> 4);
100 seqnum -= 64 * 16;
101
102 /* Every 64th of the next 2048 */
103 if (seqnum < (32 * 64))
104 return 128 + 192 + 128 + 64 + (seqnum >> 6);
105 seqnum -= 32 * 64;
106
107 /* Every 256th of the next 16384 */
108 if (seqnum < (64 * 256))
109 return 128 + 192 + 128 + 64 + 32 + (seqnum >> 8);
110 seqnum -= 64 * 256;
111
112 /* Every 512th upto 36479 (1.3 GB with 512 byte blocks).
113 * Seeking to positions behind this will get slower
114 * than dead snails nailed to the ground. But if
115 * someone uses files that large with 512-byte blocks,
116 * he or she deserves no better.
117 */
118
119 if (seqnum > (31 * 512))
120 seqnum = 31 * 512;
121 return 128 + 192 + 128 + 64 + 32 + 64 + (seqnum >> 9);
122 }
123
124 /* Now the other way round: Calculate the sequence
125 * number of an extension block of a key at the
126 * given index in the cache.
127 */
128
129 static int
130 index_to_seqnum(int index)
131 {
132 if (index < 128)
133 return index;
134 index -= 128;
135 if (index < 192)
136 return 128 + (index << 1);
137 index -= 192;
138 if (index < 128)
139 return 128 + 192 * 2 + (index << 2);
140 index -= 128;
141 if (index < 64)
142 return 128 + 192 * 2 + 128 * 4 + (index << 4);
143 index -= 64;
144 if (index < 32)
145 return 128 + 192 * 2 + 128 * 4 + 64 * 16 + (index << 6);
146 index -= 32;
147 if (index < 64)
148 return 128 + 192 * 2 + 128 * 4 + 64 * 16 + 32 * 64 + (index << 8);
149 index -= 64;
150 return 128 + 192 * 2 + 128 * 4 + 64 * 16 + 32 * 64 + 64 * 256 + (index << 9);
151 }
152
153 static s32 __inline__
154 calc_key(struct inode *inode, int *ext)
155 {
156 int index;
157 struct key_cache *kc;
158
159 for (index = 0; index < 4; index++) {
160 kc = &inode->u.affs_i.i_ec->kc[index];
161 if (kc->kc_last == -1)
162 continue; /* don't look in cache if invalid. */
163 if (*ext == kc->kc_this_seq) {
164 return kc->kc_this_key;
165 } else if (*ext == kc->kc_this_seq + 1) {
166 if (kc->kc_next_key)
167 return kc->kc_next_key;
168 else {
169 (*ext)--;
170 return kc->kc_this_key;
171 }
172 }
173 }
174 index = seqnum_to_index(*ext);
175 if (index > inode->u.affs_i.i_ec->max_ext)
176 index = inode->u.affs_i.i_ec->max_ext;
177 *ext = index_to_seqnum(index);
178 return inode->u.affs_i.i_ec->ec[index];
179 }
180
181 int
182 affs_bmap(struct inode *inode, int block)
183 {
184 struct buffer_head *bh;
185 s32 key, nkey;
186 s32 ptype, stype;
187 int ext;
188 int index;
189 int keycount;
190 struct key_cache *kc;
191 struct key_cache *tkc;
192 struct timeval tv;
193 s32 *keyp;
194 int i;
195
196 pr_debug("AFFS: bmap(%lu,%d)\n",inode->i_ino,block);
197
198 lock_kernel();
199 if (block < 0) {
200 affs_error(inode->i_sb,"bmap","Block < 0");
201 goto out_fail;
202 }
203 if (!inode->u.affs_i.i_ec) {
204 if (alloc_ext_cache(inode)) {
205 goto out_fail;
206 }
207 }
208
209 /* Try to find the requested key in the cache.
210 * In order to speed this up as much as possible,
211 * the cache line lookup is done in a separate
212 * step.
213 */
214
215 for (i = 0; i < 4; i++) {
216 tkc = &inode->u.affs_i.i_ec->kc[i];
217 /* Look in any cache if the key is there */
218 if (block <= tkc->kc_last && block >= tkc->kc_first) {
219 unlock_kernel();
220 return tkc->kc_keys[block - tkc->kc_first];
221 }
222 }
223 kc = NULL;
224 tv = xtime;
225 for (i = 0; i < 4; i++) {
226 tkc = &inode->u.affs_i.i_ec->kc[i];
227 if (tkc->kc_lru_time.tv_sec > tv.tv_sec)
228 continue;
229 if (tkc->kc_lru_time.tv_sec < tv.tv_sec ||
230 tkc->kc_lru_time.tv_usec < tv.tv_usec) {
231 kc = tkc;
232 tv = tkc->kc_lru_time;
233 }
234 }
235 if (!kc) /* Really shouldn't happen */
236 kc = tkc;
237 kc->kc_lru_time = xtime;
238 keyp = kc->kc_keys;
239 kc->kc_first = block;
240 kc->kc_last = -1;
241 keycount = AFFS_KCSIZE;
242
243 /* Calculate sequence number of the extension block where the
244 * number of the requested block is stored. 0 means it's in
245 * the file header.
246 */
247
248 ext = block / AFFS_I2HSIZE(inode);
249 key = calc_key(inode,&ext);
250 block -= ext * AFFS_I2HSIZE(inode);
251
252 for (;;) {
253 bh = affs_bread(inode->i_dev,key,AFFS_I2BSIZE(inode));
254 if (!bh)
255 goto out_fail;
256
257 index = seqnum_to_index(ext);
258 if (index > inode->u.affs_i.i_ec->max_ext &&
259 (affs_checksum_block(AFFS_I2BSIZE(inode),bh->b_data,&ptype,&stype) ||
260 (ptype != T_SHORT && ptype != T_LIST) || stype != ST_FILE)) {
261 affs_brelse(bh);
262 goto out_fail;
263 }
264 nkey = be32_to_cpu(FILE_END(bh->b_data,inode)->extension);
265 if (block < AFFS_I2HSIZE(inode)) {
266 /* Fill cache as much as possible */
267 if (keycount) {
268 kc->kc_first = ext * AFFS_I2HSIZE(inode) + block;
269 keycount = keycount < AFFS_I2HSIZE(inode) - block ? keycount :
270 AFFS_I2HSIZE(inode) - block;
271 for (i = 0; i < keycount; i++)
272 kc->kc_keys[i] = be32_to_cpu(AFFS_BLOCK(bh->b_data,inode,block + i));
273 kc->kc_last = kc->kc_first + i - 1;
274 }
275 break;
276 }
277 block -= AFFS_I2HSIZE(inode);
278 affs_brelse(bh);
279 ext++;
280 if (index > inode->u.affs_i.i_ec->max_ext && AFFS_ISINDEX(ext)) {
281 inode->u.affs_i.i_ec->ec[index] = nkey;
282 inode->u.affs_i.i_ec->max_ext = index;
283 }
284 key = nkey;
285 }
286 kc->kc_this_key = key;
287 kc->kc_this_seq = ext;
288 kc->kc_next_key = nkey;
289 key = be32_to_cpu(AFFS_BLOCK(bh->b_data,inode,block));
290 affs_brelse(bh);
291 out:
292 unlock_kernel();
293 return key;
294
295 out_fail:
296 key=0;
297 goto out;
298 }
299
300
301 static int affs_get_block(struct inode *inode, long block, struct buffer_head *bh_result, int create)
302 {
303 int err, phys=0, new=0;
304
305 if (!create) {
306 phys = affs_bmap(inode, block);
307 if (phys) {
308 bh_result->b_dev = inode->i_dev;
309 bh_result->b_blocknr = phys;
310 bh_result->b_state |= (1UL << BH_Mapped);
311 }
312 return 0;
313 }
314
315 err = -EIO;
316 lock_kernel();
317 if (block < 0)
318 goto abort_negative;
319
320 if (affs_getblock(inode, block)==NULL) {
321 err = -EIO;
322 goto abort;
323 }
324
325 bh_result->b_dev = inode->i_dev;
326 bh_result->b_blocknr = phys;
327 bh_result->b_state |= (1UL << BH_Mapped);
328 if (new)
329 bh_result->b_state |= (1UL << BH_New);
330
331 abort:
332 unlock_kernel();
333 return err;
334
335 abort_negative:
336 affs_error(inode->i_sb,"affs_get_block","Block < 0");
337 goto abort;
338
339 }
340
341 static int affs_writepage(struct file *file, struct page *page)
342 {
343 return block_write_full_page(page,affs_get_block);
344 }
345 static int affs_readpage(struct file *file, struct page *page)
346 {
347 return block_read_full_page(page,affs_get_block);
348 }
349 static int affs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
350 {
351 return cont_prepare_write(page,from,to,affs_get_block,
352 &((struct inode*)page->mapping->host)->u.affs_i.mmu_private);
353 }
354 static int _affs_bmap(struct address_space *mapping, long block)
355 {
356 return generic_block_bmap(mapping,block,affs_get_block);
357 }
358 struct address_space_operations affs_aops = {
359 readpage: affs_readpage,
360 writepage: affs_writepage,
361 sync_page: block_sync_page,
362 prepare_write: affs_prepare_write,
363 commit_write: generic_commit_write,
364 bmap: _affs_bmap
365 };
366
367 /* With the affs, getting a random block from a file is not
368 * a simple business. Since this fs does not allow holes,
369 * it may be necessary to allocate all the missing blocks
370 * in between, as well as some new extension blocks. The OFS
371 * is even worse: All data blocks contain pointers to the
372 * next ones, so you have to fix [n-1] after allocating [n].
373 * What a mess.
374 */
375
376 static struct buffer_head * affs_getblock(struct inode *inode, s32 block)
377 {
378 struct super_block *sb = inode->i_sb;
379 int ofs = sb->u.affs_sb.s_flags & SF_OFS;
380 int ext = block / AFFS_I2HSIZE(inode);
381 struct buffer_head *bh, *ebh, *pbh = NULL;
382 struct key_cache *kc;
383 s32 key, nkey;
384 int cf, j, pt;
385 int index;
386 int err;
387
388 pr_debug("AFFS: getblock(%lu,%d)\n",inode->i_ino,block);
389
390 key = calc_key(inode,&ext);
391 block -= ext * AFFS_I2HSIZE(inode);
392 pt = ext ? T_LIST : T_SHORT;
393
394 /* Key refers now to the last known extension block,
395 * ext is its sequence number (if 0, key refers to the
396 * header block), and block is the block number relative
397 * to the first block stored in that extension block.
398 */
399 for (;;) { /* Loop over header block and extension blocks */
400 struct file_front *fdp;
401
402 bh = affs_bread(inode->i_dev,key,AFFS_I2BSIZE(inode));
403 if (!bh)
404 goto out_fail;
405 fdp = (struct file_front *) bh->b_data;
406 err = affs_checksum_block(AFFS_I2BSIZE(inode),bh->b_data,&cf,&j);
407 if (err || cf != pt || j != ST_FILE) {
408 affs_error(sb, "getblock",
409 "Block %d is not a valid %s", key,
410 pt == T_SHORT ? "file header" : "ext block");
411 goto out_free_bh;
412 }
413 j = be32_to_cpu(((struct file_front *)bh->b_data)->block_count);
414 for (cf = 0; j < AFFS_I2HSIZE(inode) && j <= block; j++) {
415 if (ofs && !pbh && inode->u.affs_i.i_lastblock >= 0) {
416 if (j > 0) {
417 s32 k = AFFS_BLOCK(bh->b_data, inode, j - 1);
418 pbh = affs_bread(inode->i_dev,
419 be32_to_cpu(k),
420 AFFS_I2BSIZE(inode));
421 } else
422 pbh = affs_getblock(inode,inode->u.affs_i.i_lastblock);
423 if (!pbh) {
424 affs_error(sb,"getblock", "Cannot get last block in file");
425 break;
426 }
427 }
428 nkey = affs_new_data(inode);
429 if (!nkey)
430 break;
431 inode->u.affs_i.i_lastblock++;
432 if (AFFS_BLOCK(bh->b_data,inode,j)) {
433 affs_warning(sb,"getblock","Block already allocated");
434 affs_free_block(sb,nkey);
435 continue;
436 }
437 AFFS_BLOCK(bh->b_data,inode,j) = cpu_to_be32(nkey);
438 if (ofs) {
439 ebh = affs_bread(inode->i_dev,nkey,AFFS_I2BSIZE(inode));
440 if (!ebh) {
441 affs_error(sb,"getblock", "Cannot get block %d",nkey);
442 affs_free_block(sb,nkey);
443 AFFS_BLOCK(bh->b_data,inode,j) = 0;
444 break;
445 }
446 DATA_FRONT(ebh)->primary_type = cpu_to_be32(T_DATA);
447 DATA_FRONT(ebh)->header_key = cpu_to_be32(inode->i_ino);
448 DATA_FRONT(ebh)->sequence_number = cpu_to_be32(inode->u.affs_i.i_lastblock + 1);
449 affs_fix_checksum(AFFS_I2BSIZE(inode), ebh->b_data, 5);
450 mark_buffer_dirty(ebh);
451 if (pbh) {
452 DATA_FRONT(pbh)->data_size = cpu_to_be32(AFFS_I2BSIZE(inode) - 24);
453 DATA_FRONT(pbh)->next_data = cpu_to_be32(nkey);
454 affs_fix_checksum(AFFS_I2BSIZE(inode),pbh->b_data,5);
455 mark_buffer_dirty(pbh);
456 affs_brelse(pbh);
457 }
458 pbh = ebh;
459 }
460 cf = 1;
461 }
462 /* N.B. May need to release pbh after here */
463
464 if (cf) {
465 if (pt == T_SHORT)
466 fdp->first_data = AFFS_BLOCK(bh->b_data,inode,0);
467 fdp->block_count = cpu_to_be32(j);
468 affs_fix_checksum(AFFS_I2BSIZE(inode),bh->b_data,5);
469 mark_buffer_dirty(bh);
470 }
471
472 if (block < j) {
473 if (pbh)
474 affs_brelse(pbh);
475 break;
476 }
477 if (j < AFFS_I2HSIZE(inode)) {
478 /* N.B. What about pbh here? */
479 goto out_free_bh;
480 }
481
482 block -= AFFS_I2HSIZE(inode);
483 key = be32_to_cpu(FILE_END(bh->b_data,inode)->extension);
484 if (!key) {
485 key = affs_new_header(inode);
486 if (!key)
487 goto out_free_bh;
488 ebh = affs_bread(inode->i_dev,key,AFFS_I2BSIZE(inode));
489 if (!ebh) {
490 /* N.B. must free bh here */
491 goto out_free_block;
492 }
493 ((struct file_front *)ebh->b_data)->primary_type = cpu_to_be32(T_LIST);
494 ((struct file_front *)ebh->b_data)->own_key = cpu_to_be32(key);
495 FILE_END(ebh->b_data,inode)->secondary_type = cpu_to_be32(ST_FILE);
496 FILE_END(ebh->b_data,inode)->parent = cpu_to_be32(inode->i_ino);
497 affs_fix_checksum(AFFS_I2BSIZE(inode),ebh->b_data,5);
498 mark_buffer_dirty(ebh);
499 FILE_END(bh->b_data,inode)->extension = cpu_to_be32(key);
500 affs_fix_checksum(AFFS_I2BSIZE(inode),bh->b_data,5);
501 mark_buffer_dirty(bh);
502 affs_brelse(bh);
503 bh = ebh;
504 }
505 pt = T_LIST;
506 ext++;
507 index = seqnum_to_index(ext);
508 if (index > inode->u.affs_i.i_ec->max_ext &&
509 AFFS_ISINDEX(ext)) {
510 inode->u.affs_i.i_ec->ec[index] = key;
511 inode->u.affs_i.i_ec->max_ext = index;
512 }
513 affs_brelse(bh);
514 }
515
516 /* Invalidate key cache */
517 for (j = 0; j < 4; j++) {
518 kc = &inode->u.affs_i.i_ec->kc[j];
519 kc->kc_last = -1;
520 }
521 key = be32_to_cpu(AFFS_BLOCK(bh->b_data,inode,block));
522 affs_brelse(bh);
523 if (!key)
524 goto out_fail;
525
526 bh = affs_bread(inode->i_dev, key, AFFS_I2BSIZE(inode));
527 return bh;
528
529 out_free_block:
530 affs_free_block(sb, key);
531 out_free_bh:
532 affs_brelse(bh);
533 out_fail:
534 return NULL;
535 }
536
537 static ssize_t
538 affs_file_read_ofs(struct file *filp, char *buf, size_t count, loff_t *ppos)
539 {
540 struct inode *inode = filp->f_dentry->d_inode;
541 char *start;
542 ssize_t left, offset, size, sector;
543 ssize_t blocksize;
544 struct buffer_head *bh;
545 void *data;
546 loff_t tmp;
547
548 pr_debug("AFFS: file_read_ofs(ino=%lu,pos=%lu,%d)\n",inode->i_ino,
549 (unsigned long)*ppos,count);
550
551 if (!inode) {
552 affs_error(inode->i_sb,"file_read_ofs","Inode = NULL");
553 return -EINVAL;
554 }
555 blocksize = AFFS_I2BSIZE(inode) - 24;
556 if (!(S_ISREG(inode->i_mode))) {
557 pr_debug("AFFS: file_read: mode = %07o",inode->i_mode);
558 return -EINVAL;
559 }
560 if (*ppos >= inode->i_size || count <= 0)
561 return 0;
562
563 start = buf;
564 for (;;) {
565 left = MIN (inode->i_size - *ppos,count - (buf - start));
566 if (!left)
567 break;
568 tmp = *ppos;
569 do_div(tmp, blocksize);
570 sector = affs_bmap(inode, tmp);
571 if (!sector)
572 break;
573 tmp = *ppos;
574 offset = do_div(tmp, blocksize);
575 bh = affs_bread(inode->i_dev,sector,AFFS_I2BSIZE(inode));
576 if (!bh)
577 break;
578 data = bh->b_data + 24;
579 size = MIN(blocksize - offset,left);
580 *ppos += size;
581 copy_to_user(buf,data + offset,size);
582 buf += size;
583 affs_brelse(bh);
584 }
585 if (start == buf)
586 return -EIO;
587 return buf - start;
588 }
589
590 static ssize_t
591 affs_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
592 {
593 ssize_t retval;
594
595 retval = generic_file_write (file, buf, count, ppos);
596 if (retval >0) {
597 struct inode *inode = file->f_dentry->d_inode;
598 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
599 mark_inode_dirty(inode);
600 }
601 return retval;
602 }
603
604 static ssize_t
605 affs_file_write_ofs(struct file *file, const char *buf, size_t count, loff_t *ppos)
606 {
607 ssize_t retval;
608
609 retval = generic_file_write (file, buf, count, ppos);
610 if (retval >0) {
611 struct inode *inode = file->f_dentry->d_inode;
612 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
613 mark_inode_dirty(inode);
614 }
615 return retval;
616 }
617
618 /* Free any preallocated blocks. */
619
620 void
621 affs_free_prealloc(struct inode *inode)
622 {
623 struct super_block *sb = inode->i_sb;
624 struct affs_zone *zone;
625 int block;
626
627 pr_debug("AFFS: free_prealloc(ino=%lu)\n", inode->i_ino);
628
629 while (inode->u.affs_i.i_pa_cnt) {
630 block = inode->u.affs_i.i_data[inode->u.affs_i.i_pa_next++];
631 inode->u.affs_i.i_pa_next &= AFFS_MAX_PREALLOC - 1;
632 inode->u.affs_i.i_pa_cnt--;
633 affs_free_block(sb, block);
634 }
635 if (inode->u.affs_i.i_zone) {
636 zone = &sb->u.affs_sb.s_zones[inode->u.affs_i.i_zone];
637 if (zone->z_ino == inode->i_ino)
638 zone->z_ino = 0;
639 }
640 }
641
642 /* Truncate (or enlarge) a file to the requested size. */
643
644 void
645 affs_truncate(struct inode *inode)
646 {
647 struct buffer_head *bh = NULL;
648 int first; /* First block to be thrown away */
649 int block;
650 s32 key;
651 s32 *keyp;
652 s32 ekey;
653 s32 ptype, stype;
654 int freethis;
655 int net_blocksize;
656 int blocksize = AFFS_I2BSIZE(inode);
657 int rem;
658 int ext;
659 loff_t tmp;
660
661 pr_debug("AFFS: truncate(inode=%ld,size=%lu)\n",inode->i_ino,inode->i_size);
662
663 net_blocksize = blocksize - ((inode->i_sb->u.affs_sb.s_flags & SF_OFS) ? 24 : 0);
664 first = inode->i_size + net_blocksize -1;
665 do_div (first, net_blocksize);
666 if (inode->u.affs_i.i_lastblock < first - 1) {
667 /* There has to be at least one new block to be allocated */
668 if (!inode->u.affs_i.i_ec && alloc_ext_cache(inode)) {
669 /* XXX Fine! No way to indicate an error. */
670 return /* -ENOSPC */;
671 }
672 bh = affs_getblock(inode,first - 1);
673 if (!bh) {
674 affs_warning(inode->i_sb,"truncate","Cannot extend file");
675 inode->i_size = net_blocksize * (inode->u.affs_i.i_lastblock + 1);
676 } else if (inode->i_sb->u.affs_sb.s_flags & SF_OFS) {
677 tmp = inode->i_size;
678 rem = do_div(tmp, net_blocksize);
679 DATA_FRONT(bh)->data_size = cpu_to_be32(rem ? rem : net_blocksize);
680 affs_fix_checksum(blocksize,bh->b_data,5);
681 mark_buffer_dirty(bh);
682 }
683 goto out_truncate;
684 }
685 ekey = inode->i_ino;
686 ext = 0;
687
688 /* Free all blocks starting at 'first' and all then-empty
689 * extension blocks. Do not free the header block, though.
690 */
691 while (ekey) {
692 if (!(bh = affs_bread(inode->i_dev,ekey,blocksize))) {
693 affs_error(inode->i_sb,"truncate","Cannot read block %d",ekey);
694 goto out_truncate;
695 }
696 if (affs_checksum_block(blocksize,bh->b_data,&ptype,&stype)) {
697 affs_error(inode->i_sb,"truncate","Checksum error in header/ext block %d",
698 ekey);
699 goto out_truncate;
700 }
701 if (stype != ST_FILE || (ptype != T_SHORT && ptype != T_LIST)) {
702 affs_error(inode->i_sb,"truncate",
703 "Bad block (key=%d, ptype=%d, stype=%d)",ekey,ptype,stype);
704 goto out_truncate;
705 }
706 /* Do we have to free this extension block after
707 * freeing the data blocks pointed to?
708 */
709 freethis = first == 0 && ekey != inode->i_ino;
710
711 /* Free the data blocks. 'first' is relative to this
712 * extension block and may well lie behind this block.
713 */
714 for (block = first; block < AFFS_I2HSIZE(inode); block++) {
715 keyp = &AFFS_BLOCK(bh->b_data,inode,block);
716 key = be32_to_cpu(*keyp);
717 if (key) {
718 *keyp = 0;
719 affs_free_block(inode->i_sb,key);
720 } else
721 break;
722 }
723 keyp = &GET_END_PTR(struct file_end,bh->b_data,blocksize)->extension;
724 key = be32_to_cpu(*keyp);
725
726 /* If 'first' is in this block or is the first
727 * in the next one, this will be the last in
728 * the list, thus we have to adjust the count
729 * and zero the pointer to the next ext block.
730 */
731 if (first <= AFFS_I2HSIZE(inode)) {
732 ((struct file_front *)bh->b_data)->block_count = cpu_to_be32(first);
733 first = 0;
734 *keyp = 0;
735 affs_fix_checksum(blocksize,bh->b_data,5);
736 mark_buffer_dirty(bh);
737 } else
738 first -= AFFS_I2HSIZE(inode);
739 affs_brelse(bh);
740 bh = NULL;
741 if (freethis) /* Don't bother fixing checksum */
742 affs_free_block(inode->i_sb,ekey);
743 ekey = key;
744 }
745 block = inode->i_size + net_blocksize - 1;
746 do_div (block, net_blocksize);
747 block--;
748 inode->u.affs_i.i_lastblock = block;
749
750 /* If the file is not truncated to a block boundary,
751 * the partial block after the EOF must be zeroed
752 * so it cannot become accessible again.
753 */
754
755 tmp = inode->i_size;
756 rem = do_div(tmp, net_blocksize);
757 if (rem) {
758 if ((inode->i_sb->u.affs_sb.s_flags & SF_OFS))
759 rem += 24;
760 pr_debug("AFFS: Zeroing from offset %d in block %d\n",rem,block);
761 bh = affs_getblock(inode,block);
762 if (bh) {
763 memset(bh->b_data + rem,0,blocksize - rem);
764 if ((inode->i_sb->u.affs_sb.s_flags & SF_OFS)) {
765 ((struct data_front *)bh->b_data)->data_size = cpu_to_be32(rem);
766 ((struct data_front *)bh->b_data)->next_data = 0;
767 affs_fix_checksum(blocksize,bh->b_data,5);
768 }
769 mark_buffer_dirty(bh);
770 } else
771 affs_error(inode->i_sb,"truncate","Cannot read block %d",block);
772 }
773
774 out_truncate:
775 affs_brelse(bh);
776 /* Invalidate cache */
777 if (inode->u.affs_i.i_ec) {
778 inode->u.affs_i.i_ec->max_ext = 0;
779 for (key = 0; key < 4; key++) {
780 inode->u.affs_i.i_ec->kc[key].kc_next_key = 0;
781 inode->u.affs_i.i_ec->kc[key].kc_last = -1;
782 }
783 }
784 mark_inode_dirty(inode);
785 }
786
787 /*
788 * Called only when we need to allocate the extension cache.
789 */
790
791 static int
792 alloc_ext_cache(struct inode *inode)
793 {
794 s32 key;
795 int i;
796 unsigned long cache_page;
797 int error = 0;
798
799 pr_debug("AFFS: alloc_ext_cache(ino=%lu)\n",inode->i_ino);
800
801 cache_page = get_free_page(GFP_KERNEL);
802 /*
803 * Check whether somebody else allocated it for us ...
804 */
805 if (inode->u.affs_i.i_ec)
806 goto out_free;
807 if (!cache_page)
808 goto out_error;
809
810 inode->u.affs_i.i_ec = (struct ext_cache *) cache_page;
811 /* We only have to initialize non-zero values.
812 * get_free_page() zeroed the page already.
813 */
814 key = inode->i_ino;
815 inode->u.affs_i.i_ec->ec[0] = key;
816 for (i = 0; i < 4; i++) {
817 inode->u.affs_i.i_ec->kc[i].kc_this_key = key;
818 inode->u.affs_i.i_ec->kc[i].kc_last = -1;
819 }
820 out:
821 return error;
822
823 out_free:
824 if (cache_page)
825 free_page(cache_page);
826 goto out;
827
828 out_error:
829 affs_error(inode->i_sb,"alloc_ext_cache","Cache allocation failed");
830 error = -ENOMEM;
831 goto out;
832 }
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