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41#include <linux/pagemap.h>
42#include "nilfs.h"
43#include "page.h"
44
45static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
46{
47 unsigned int len = le16_to_cpu(dlen);
48
49#if (PAGE_SIZE >= 65536)
50 if (len == NILFS_MAX_REC_LEN)
51 return 1 << 16;
52#endif
53 return len;
54}
55
56static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
57{
58#if (PAGE_SIZE >= 65536)
59 if (len == (1 << 16))
60 return cpu_to_le16(NILFS_MAX_REC_LEN);
61
62 BUG_ON(len > (1 << 16));
63#endif
64 return cpu_to_le16(len);
65}
66
67
68
69
70
71static inline unsigned int nilfs_chunk_size(struct inode *inode)
72{
73 return inode->i_sb->s_blocksize;
74}
75
76static inline void nilfs_put_page(struct page *page)
77{
78 kunmap(page);
79 put_page(page);
80}
81
82
83
84
85
86static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
87{
88 unsigned int last_byte = inode->i_size;
89
90 last_byte -= page_nr << PAGE_SHIFT;
91 if (last_byte > PAGE_SIZE)
92 last_byte = PAGE_SIZE;
93 return last_byte;
94}
95
96static int nilfs_prepare_chunk(struct page *page, unsigned int from,
97 unsigned int to)
98{
99 loff_t pos = page_offset(page) + from;
100
101 return __block_write_begin(page, pos, to - from, nilfs_get_block);
102}
103
104static void nilfs_commit_chunk(struct page *page,
105 struct address_space *mapping,
106 unsigned int from, unsigned int to)
107{
108 struct inode *dir = mapping->host;
109 loff_t pos = page_offset(page) + from;
110 unsigned int len = to - from;
111 unsigned int nr_dirty, copied;
112 int err;
113
114 nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
115 copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
116 if (pos + copied > dir->i_size)
117 i_size_write(dir, pos + copied);
118 if (IS_DIRSYNC(dir))
119 nilfs_set_transaction_flag(NILFS_TI_SYNC);
120 err = nilfs_set_file_dirty(dir, nr_dirty);
121 WARN_ON(err);
122 unlock_page(page);
123}
124
125static bool nilfs_check_page(struct page *page)
126{
127 struct inode *dir = page->mapping->host;
128 struct super_block *sb = dir->i_sb;
129 unsigned int chunk_size = nilfs_chunk_size(dir);
130 char *kaddr = page_address(page);
131 unsigned int offs, rec_len;
132 unsigned int limit = PAGE_SIZE;
133 struct nilfs_dir_entry *p;
134 char *error;
135
136 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
137 limit = dir->i_size & ~PAGE_MASK;
138 if (limit & (chunk_size - 1))
139 goto Ebadsize;
140 if (!limit)
141 goto out;
142 }
143 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
144 p = (struct nilfs_dir_entry *)(kaddr + offs);
145 rec_len = nilfs_rec_len_from_disk(p->rec_len);
146
147 if (rec_len < NILFS_DIR_REC_LEN(1))
148 goto Eshort;
149 if (rec_len & 3)
150 goto Ealign;
151 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
152 goto Enamelen;
153 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
154 goto Espan;
155 }
156 if (offs != limit)
157 goto Eend;
158out:
159 SetPageChecked(page);
160 return true;
161
162
163
164Ebadsize:
165 nilfs_error(sb,
166 "size of directory #%lu is not a multiple of chunk size",
167 dir->i_ino);
168 goto fail;
169Eshort:
170 error = "rec_len is smaller than minimal";
171 goto bad_entry;
172Ealign:
173 error = "unaligned directory entry";
174 goto bad_entry;
175Enamelen:
176 error = "rec_len is too small for name_len";
177 goto bad_entry;
178Espan:
179 error = "directory entry across blocks";
180bad_entry:
181 nilfs_error(sb,
182 "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
183 dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
184 (unsigned long)le64_to_cpu(p->inode),
185 rec_len, p->name_len);
186 goto fail;
187Eend:
188 p = (struct nilfs_dir_entry *)(kaddr + offs);
189 nilfs_error(sb,
190 "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
191 dir->i_ino, (page->index << PAGE_SHIFT) + offs,
192 (unsigned long)le64_to_cpu(p->inode));
193fail:
194 SetPageError(page);
195 return false;
196}
197
198static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
199{
200 struct address_space *mapping = dir->i_mapping;
201 struct page *page = read_mapping_page(mapping, n, NULL);
202
203 if (!IS_ERR(page)) {
204 kmap(page);
205 if (unlikely(!PageChecked(page))) {
206 if (PageError(page) || !nilfs_check_page(page))
207 goto fail;
208 }
209 }
210 return page;
211
212fail:
213 nilfs_put_page(page);
214 return ERR_PTR(-EIO);
215}
216
217
218
219
220
221
222static int
223nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
224{
225 if (len != de->name_len)
226 return 0;
227 if (!de->inode)
228 return 0;
229 return !memcmp(name, de->name, len);
230}
231
232
233
234
235static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
236{
237 return (struct nilfs_dir_entry *)((char *)p +
238 nilfs_rec_len_from_disk(p->rec_len));
239}
240
241static unsigned char
242nilfs_filetype_table[NILFS_FT_MAX] = {
243 [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
244 [NILFS_FT_REG_FILE] = DT_REG,
245 [NILFS_FT_DIR] = DT_DIR,
246 [NILFS_FT_CHRDEV] = DT_CHR,
247 [NILFS_FT_BLKDEV] = DT_BLK,
248 [NILFS_FT_FIFO] = DT_FIFO,
249 [NILFS_FT_SOCK] = DT_SOCK,
250 [NILFS_FT_SYMLINK] = DT_LNK,
251};
252
253#define S_SHIFT 12
254static unsigned char
255nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
256 [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
257 [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
258 [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
259 [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
260 [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
261 [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
262 [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
263};
264
265static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
266{
267 umode_t mode = inode->i_mode;
268
269 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
270}
271
272static int nilfs_readdir(struct file *file, struct dir_context *ctx)
273{
274 loff_t pos = ctx->pos;
275 struct inode *inode = file_inode(file);
276 struct super_block *sb = inode->i_sb;
277 unsigned int offset = pos & ~PAGE_MASK;
278 unsigned long n = pos >> PAGE_SHIFT;
279 unsigned long npages = dir_pages(inode);
280
281 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
282 return 0;
283
284 for ( ; n < npages; n++, offset = 0) {
285 char *kaddr, *limit;
286 struct nilfs_dir_entry *de;
287 struct page *page = nilfs_get_page(inode, n);
288
289 if (IS_ERR(page)) {
290 nilfs_error(sb, "bad page in #%lu", inode->i_ino);
291 ctx->pos += PAGE_SIZE - offset;
292 return -EIO;
293 }
294 kaddr = page_address(page);
295 de = (struct nilfs_dir_entry *)(kaddr + offset);
296 limit = kaddr + nilfs_last_byte(inode, n) -
297 NILFS_DIR_REC_LEN(1);
298 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
299 if (de->rec_len == 0) {
300 nilfs_error(sb, "zero-length directory entry");
301 nilfs_put_page(page);
302 return -EIO;
303 }
304 if (de->inode) {
305 unsigned char t;
306
307 if (de->file_type < NILFS_FT_MAX)
308 t = nilfs_filetype_table[de->file_type];
309 else
310 t = DT_UNKNOWN;
311
312 if (!dir_emit(ctx, de->name, de->name_len,
313 le64_to_cpu(de->inode), t)) {
314 nilfs_put_page(page);
315 return 0;
316 }
317 }
318 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
319 }
320 nilfs_put_page(page);
321 }
322 return 0;
323}
324
325
326
327
328
329
330
331
332
333struct nilfs_dir_entry *
334nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
335 struct page **res_page)
336{
337 const unsigned char *name = qstr->name;
338 int namelen = qstr->len;
339 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
340 unsigned long start, n;
341 unsigned long npages = dir_pages(dir);
342 struct page *page = NULL;
343 struct nilfs_inode_info *ei = NILFS_I(dir);
344 struct nilfs_dir_entry *de;
345
346 if (npages == 0)
347 goto out;
348
349
350 *res_page = NULL;
351
352 start = ei->i_dir_start_lookup;
353 if (start >= npages)
354 start = 0;
355 n = start;
356 do {
357 char *kaddr;
358
359 page = nilfs_get_page(dir, n);
360 if (!IS_ERR(page)) {
361 kaddr = page_address(page);
362 de = (struct nilfs_dir_entry *)kaddr;
363 kaddr += nilfs_last_byte(dir, n) - reclen;
364 while ((char *) de <= kaddr) {
365 if (de->rec_len == 0) {
366 nilfs_error(dir->i_sb,
367 "zero-length directory entry");
368 nilfs_put_page(page);
369 goto out;
370 }
371 if (nilfs_match(namelen, name, de))
372 goto found;
373 de = nilfs_next_entry(de);
374 }
375 nilfs_put_page(page);
376 }
377 if (++n >= npages)
378 n = 0;
379
380 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
381 nilfs_error(dir->i_sb,
382 "dir %lu size %lld exceeds block count %llu",
383 dir->i_ino, dir->i_size,
384 (unsigned long long)dir->i_blocks);
385 goto out;
386 }
387 } while (n != start);
388out:
389 return NULL;
390
391found:
392 *res_page = page;
393 ei->i_dir_start_lookup = n;
394 return de;
395}
396
397struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
398{
399 struct page *page = nilfs_get_page(dir, 0);
400 struct nilfs_dir_entry *de = NULL;
401
402 if (!IS_ERR(page)) {
403 de = nilfs_next_entry(
404 (struct nilfs_dir_entry *)page_address(page));
405 *p = page;
406 }
407 return de;
408}
409
410ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
411{
412 ino_t res = 0;
413 struct nilfs_dir_entry *de;
414 struct page *page;
415
416 de = nilfs_find_entry(dir, qstr, &page);
417 if (de) {
418 res = le64_to_cpu(de->inode);
419 kunmap(page);
420 put_page(page);
421 }
422 return res;
423}
424
425
426void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
427 struct page *page, struct inode *inode)
428{
429 unsigned int from = (char *)de - (char *)page_address(page);
430 unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
431 struct address_space *mapping = page->mapping;
432 int err;
433
434 lock_page(page);
435 err = nilfs_prepare_chunk(page, from, to);
436 BUG_ON(err);
437 de->inode = cpu_to_le64(inode->i_ino);
438 nilfs_set_de_type(de, inode);
439 nilfs_commit_chunk(page, mapping, from, to);
440 nilfs_put_page(page);
441 dir->i_mtime = dir->i_ctime = current_time(dir);
442}
443
444
445
446
447int nilfs_add_link(struct dentry *dentry, struct inode *inode)
448{
449 struct inode *dir = d_inode(dentry->d_parent);
450 const unsigned char *name = dentry->d_name.name;
451 int namelen = dentry->d_name.len;
452 unsigned int chunk_size = nilfs_chunk_size(dir);
453 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
454 unsigned short rec_len, name_len;
455 struct page *page = NULL;
456 struct nilfs_dir_entry *de;
457 unsigned long npages = dir_pages(dir);
458 unsigned long n;
459 char *kaddr;
460 unsigned int from, to;
461 int err;
462
463
464
465
466
467
468 for (n = 0; n <= npages; n++) {
469 char *dir_end;
470
471 page = nilfs_get_page(dir, n);
472 err = PTR_ERR(page);
473 if (IS_ERR(page))
474 goto out;
475 lock_page(page);
476 kaddr = page_address(page);
477 dir_end = kaddr + nilfs_last_byte(dir, n);
478 de = (struct nilfs_dir_entry *)kaddr;
479 kaddr += PAGE_SIZE - reclen;
480 while ((char *)de <= kaddr) {
481 if ((char *)de == dir_end) {
482
483 name_len = 0;
484 rec_len = chunk_size;
485 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
486 de->inode = 0;
487 goto got_it;
488 }
489 if (de->rec_len == 0) {
490 nilfs_error(dir->i_sb,
491 "zero-length directory entry");
492 err = -EIO;
493 goto out_unlock;
494 }
495 err = -EEXIST;
496 if (nilfs_match(namelen, name, de))
497 goto out_unlock;
498 name_len = NILFS_DIR_REC_LEN(de->name_len);
499 rec_len = nilfs_rec_len_from_disk(de->rec_len);
500 if (!de->inode && rec_len >= reclen)
501 goto got_it;
502 if (rec_len >= name_len + reclen)
503 goto got_it;
504 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
505 }
506 unlock_page(page);
507 nilfs_put_page(page);
508 }
509 BUG();
510 return -EINVAL;
511
512got_it:
513 from = (char *)de - (char *)page_address(page);
514 to = from + rec_len;
515 err = nilfs_prepare_chunk(page, from, to);
516 if (err)
517 goto out_unlock;
518 if (de->inode) {
519 struct nilfs_dir_entry *de1;
520
521 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
522 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
523 de->rec_len = nilfs_rec_len_to_disk(name_len);
524 de = de1;
525 }
526 de->name_len = namelen;
527 memcpy(de->name, name, namelen);
528 de->inode = cpu_to_le64(inode->i_ino);
529 nilfs_set_de_type(de, inode);
530 nilfs_commit_chunk(page, page->mapping, from, to);
531 dir->i_mtime = dir->i_ctime = current_time(dir);
532 nilfs_mark_inode_dirty(dir);
533
534out_put:
535 nilfs_put_page(page);
536out:
537 return err;
538out_unlock:
539 unlock_page(page);
540 goto out_put;
541}
542
543
544
545
546
547int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
548{
549 struct address_space *mapping = page->mapping;
550 struct inode *inode = mapping->host;
551 char *kaddr = page_address(page);
552 unsigned int from, to;
553 struct nilfs_dir_entry *de, *pde = NULL;
554 int err;
555
556 from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
557 to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
558 de = (struct nilfs_dir_entry *)(kaddr + from);
559
560 while ((char *)de < (char *)dir) {
561 if (de->rec_len == 0) {
562 nilfs_error(inode->i_sb,
563 "zero-length directory entry");
564 err = -EIO;
565 goto out;
566 }
567 pde = de;
568 de = nilfs_next_entry(de);
569 }
570 if (pde)
571 from = (char *)pde - (char *)page_address(page);
572 lock_page(page);
573 err = nilfs_prepare_chunk(page, from, to);
574 BUG_ON(err);
575 if (pde)
576 pde->rec_len = nilfs_rec_len_to_disk(to - from);
577 dir->inode = 0;
578 nilfs_commit_chunk(page, mapping, from, to);
579 inode->i_ctime = inode->i_mtime = current_time(inode);
580out:
581 nilfs_put_page(page);
582 return err;
583}
584
585
586
587
588int nilfs_make_empty(struct inode *inode, struct inode *parent)
589{
590 struct address_space *mapping = inode->i_mapping;
591 struct page *page = grab_cache_page(mapping, 0);
592 unsigned int chunk_size = nilfs_chunk_size(inode);
593 struct nilfs_dir_entry *de;
594 int err;
595 void *kaddr;
596
597 if (!page)
598 return -ENOMEM;
599
600 err = nilfs_prepare_chunk(page, 0, chunk_size);
601 if (unlikely(err)) {
602 unlock_page(page);
603 goto fail;
604 }
605 kaddr = kmap_atomic(page);
606 memset(kaddr, 0, chunk_size);
607 de = (struct nilfs_dir_entry *)kaddr;
608 de->name_len = 1;
609 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
610 memcpy(de->name, ".\0\0", 4);
611 de->inode = cpu_to_le64(inode->i_ino);
612 nilfs_set_de_type(de, inode);
613
614 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
615 de->name_len = 2;
616 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
617 de->inode = cpu_to_le64(parent->i_ino);
618 memcpy(de->name, "..\0", 4);
619 nilfs_set_de_type(de, inode);
620 kunmap_atomic(kaddr);
621 nilfs_commit_chunk(page, mapping, 0, chunk_size);
622fail:
623 put_page(page);
624 return err;
625}
626
627
628
629
630int nilfs_empty_dir(struct inode *inode)
631{
632 struct page *page = NULL;
633 unsigned long i, npages = dir_pages(inode);
634
635 for (i = 0; i < npages; i++) {
636 char *kaddr;
637 struct nilfs_dir_entry *de;
638
639 page = nilfs_get_page(inode, i);
640 if (IS_ERR(page))
641 continue;
642
643 kaddr = page_address(page);
644 de = (struct nilfs_dir_entry *)kaddr;
645 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
646
647 while ((char *)de <= kaddr) {
648 if (de->rec_len == 0) {
649 nilfs_error(inode->i_sb,
650 "zero-length directory entry (kaddr=%p, de=%p)",
651 kaddr, de);
652 goto not_empty;
653 }
654 if (de->inode != 0) {
655
656 if (de->name[0] != '.')
657 goto not_empty;
658 if (de->name_len > 2)
659 goto not_empty;
660 if (de->name_len < 2) {
661 if (de->inode !=
662 cpu_to_le64(inode->i_ino))
663 goto not_empty;
664 } else if (de->name[1] != '.')
665 goto not_empty;
666 }
667 de = nilfs_next_entry(de);
668 }
669 nilfs_put_page(page);
670 }
671 return 1;
672
673not_empty:
674 nilfs_put_page(page);
675 return 0;
676}
677
678const struct file_operations nilfs_dir_operations = {
679 .llseek = generic_file_llseek,
680 .read = generic_read_dir,
681 .iterate_shared = nilfs_readdir,
682 .unlocked_ioctl = nilfs_ioctl,
683#ifdef CONFIG_COMPAT
684 .compat_ioctl = nilfs_compat_ioctl,
685#endif
686 .fsync = nilfs_sync_file,
687
688};
689