Loading...
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * dir.c - NILFS directory entry operations
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Modified for NILFS by Amagai Yoshiji.
8 */
9/*
10 * linux/fs/ext2/dir.c
11 *
12 * Copyright (C) 1992, 1993, 1994, 1995
13 * Remy Card (card@masi.ibp.fr)
14 * Laboratoire MASI - Institut Blaise Pascal
15 * Universite Pierre et Marie Curie (Paris VI)
16 *
17 * from
18 *
19 * linux/fs/minix/dir.c
20 *
21 * Copyright (C) 1991, 1992 Linus Torvalds
22 *
23 * ext2 directory handling functions
24 *
25 * Big-endian to little-endian byte-swapping/bitmaps by
26 * David S. Miller (davem@caip.rutgers.edu), 1995
27 *
28 * All code that works with directory layout had been switched to pagecache
29 * and moved here. AV
30 */
31
32#include <linux/pagemap.h>
33#include "nilfs.h"
34#include "page.h"
35
36static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
37{
38 unsigned int len = le16_to_cpu(dlen);
39
40#if (PAGE_SIZE >= 65536)
41 if (len == NILFS_MAX_REC_LEN)
42 return 1 << 16;
43#endif
44 return len;
45}
46
47static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
48{
49#if (PAGE_SIZE >= 65536)
50 if (len == (1 << 16))
51 return cpu_to_le16(NILFS_MAX_REC_LEN);
52
53 BUG_ON(len > (1 << 16));
54#endif
55 return cpu_to_le16(len);
56}
57
58/*
59 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
60 * more robust, but we have what we have
61 */
62static inline unsigned int nilfs_chunk_size(struct inode *inode)
63{
64 return inode->i_sb->s_blocksize;
65}
66
67static inline void nilfs_put_page(struct page *page)
68{
69 kunmap(page);
70 put_page(page);
71}
72
73/*
74 * Return the offset into page `page_nr' of the last valid
75 * byte in that page, plus one.
76 */
77static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
78{
79 unsigned int last_byte = inode->i_size;
80
81 last_byte -= page_nr << PAGE_SHIFT;
82 if (last_byte > PAGE_SIZE)
83 last_byte = PAGE_SIZE;
84 return last_byte;
85}
86
87static int nilfs_prepare_chunk(struct page *page, unsigned int from,
88 unsigned int to)
89{
90 loff_t pos = page_offset(page) + from;
91
92 return __block_write_begin(page, pos, to - from, nilfs_get_block);
93}
94
95static void nilfs_commit_chunk(struct page *page,
96 struct address_space *mapping,
97 unsigned int from, unsigned int to)
98{
99 struct inode *dir = mapping->host;
100 loff_t pos = page_offset(page) + from;
101 unsigned int len = to - from;
102 unsigned int nr_dirty, copied;
103 int err;
104
105 nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
106 copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
107 if (pos + copied > dir->i_size)
108 i_size_write(dir, pos + copied);
109 if (IS_DIRSYNC(dir))
110 nilfs_set_transaction_flag(NILFS_TI_SYNC);
111 err = nilfs_set_file_dirty(dir, nr_dirty);
112 WARN_ON(err); /* do not happen */
113 unlock_page(page);
114}
115
116static bool nilfs_check_page(struct page *page)
117{
118 struct inode *dir = page->mapping->host;
119 struct super_block *sb = dir->i_sb;
120 unsigned int chunk_size = nilfs_chunk_size(dir);
121 char *kaddr = page_address(page);
122 unsigned int offs, rec_len;
123 unsigned int limit = PAGE_SIZE;
124 struct nilfs_dir_entry *p;
125 char *error;
126
127 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
128 limit = dir->i_size & ~PAGE_MASK;
129 if (limit & (chunk_size - 1))
130 goto Ebadsize;
131 if (!limit)
132 goto out;
133 }
134 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
135 p = (struct nilfs_dir_entry *)(kaddr + offs);
136 rec_len = nilfs_rec_len_from_disk(p->rec_len);
137
138 if (rec_len < NILFS_DIR_REC_LEN(1))
139 goto Eshort;
140 if (rec_len & 3)
141 goto Ealign;
142 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
143 goto Enamelen;
144 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
145 goto Espan;
146 }
147 if (offs != limit)
148 goto Eend;
149out:
150 SetPageChecked(page);
151 return true;
152
153 /* Too bad, we had an error */
154
155Ebadsize:
156 nilfs_error(sb,
157 "size of directory #%lu is not a multiple of chunk size",
158 dir->i_ino);
159 goto fail;
160Eshort:
161 error = "rec_len is smaller than minimal";
162 goto bad_entry;
163Ealign:
164 error = "unaligned directory entry";
165 goto bad_entry;
166Enamelen:
167 error = "rec_len is too small for name_len";
168 goto bad_entry;
169Espan:
170 error = "directory entry across blocks";
171bad_entry:
172 nilfs_error(sb,
173 "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
174 dir->i_ino, error, (page->index << PAGE_SHIFT) + offs,
175 (unsigned long)le64_to_cpu(p->inode),
176 rec_len, p->name_len);
177 goto fail;
178Eend:
179 p = (struct nilfs_dir_entry *)(kaddr + offs);
180 nilfs_error(sb,
181 "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
182 dir->i_ino, (page->index << PAGE_SHIFT) + offs,
183 (unsigned long)le64_to_cpu(p->inode));
184fail:
185 SetPageError(page);
186 return false;
187}
188
189static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
190{
191 struct address_space *mapping = dir->i_mapping;
192 struct page *page = read_mapping_page(mapping, n, NULL);
193
194 if (!IS_ERR(page)) {
195 kmap(page);
196 if (unlikely(!PageChecked(page))) {
197 if (PageError(page) || !nilfs_check_page(page))
198 goto fail;
199 }
200 }
201 return page;
202
203fail:
204 nilfs_put_page(page);
205 return ERR_PTR(-EIO);
206}
207
208/*
209 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
210 *
211 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
212 */
213static int
214nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
215{
216 if (len != de->name_len)
217 return 0;
218 if (!de->inode)
219 return 0;
220 return !memcmp(name, de->name, len);
221}
222
223/*
224 * p is at least 6 bytes before the end of page
225 */
226static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
227{
228 return (struct nilfs_dir_entry *)((char *)p +
229 nilfs_rec_len_from_disk(p->rec_len));
230}
231
232static unsigned char
233nilfs_filetype_table[NILFS_FT_MAX] = {
234 [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
235 [NILFS_FT_REG_FILE] = DT_REG,
236 [NILFS_FT_DIR] = DT_DIR,
237 [NILFS_FT_CHRDEV] = DT_CHR,
238 [NILFS_FT_BLKDEV] = DT_BLK,
239 [NILFS_FT_FIFO] = DT_FIFO,
240 [NILFS_FT_SOCK] = DT_SOCK,
241 [NILFS_FT_SYMLINK] = DT_LNK,
242};
243
244#define S_SHIFT 12
245static unsigned char
246nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
247 [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
248 [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
249 [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
250 [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
251 [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
252 [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
253 [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
254};
255
256static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
257{
258 umode_t mode = inode->i_mode;
259
260 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
261}
262
263static int nilfs_readdir(struct file *file, struct dir_context *ctx)
264{
265 loff_t pos = ctx->pos;
266 struct inode *inode = file_inode(file);
267 struct super_block *sb = inode->i_sb;
268 unsigned int offset = pos & ~PAGE_MASK;
269 unsigned long n = pos >> PAGE_SHIFT;
270 unsigned long npages = dir_pages(inode);
271
272 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
273 return 0;
274
275 for ( ; n < npages; n++, offset = 0) {
276 char *kaddr, *limit;
277 struct nilfs_dir_entry *de;
278 struct page *page = nilfs_get_page(inode, n);
279
280 if (IS_ERR(page)) {
281 nilfs_error(sb, "bad page in #%lu", inode->i_ino);
282 ctx->pos += PAGE_SIZE - offset;
283 return -EIO;
284 }
285 kaddr = page_address(page);
286 de = (struct nilfs_dir_entry *)(kaddr + offset);
287 limit = kaddr + nilfs_last_byte(inode, n) -
288 NILFS_DIR_REC_LEN(1);
289 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
290 if (de->rec_len == 0) {
291 nilfs_error(sb, "zero-length directory entry");
292 nilfs_put_page(page);
293 return -EIO;
294 }
295 if (de->inode) {
296 unsigned char t;
297
298 if (de->file_type < NILFS_FT_MAX)
299 t = nilfs_filetype_table[de->file_type];
300 else
301 t = DT_UNKNOWN;
302
303 if (!dir_emit(ctx, de->name, de->name_len,
304 le64_to_cpu(de->inode), t)) {
305 nilfs_put_page(page);
306 return 0;
307 }
308 }
309 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
310 }
311 nilfs_put_page(page);
312 }
313 return 0;
314}
315
316/*
317 * nilfs_find_entry()
318 *
319 * finds an entry in the specified directory with the wanted name. It
320 * returns the page in which the entry was found, and the entry itself
321 * (as a parameter - res_dir). Page is returned mapped and unlocked.
322 * Entry is guaranteed to be valid.
323 */
324struct nilfs_dir_entry *
325nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
326 struct page **res_page)
327{
328 const unsigned char *name = qstr->name;
329 int namelen = qstr->len;
330 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
331 unsigned long start, n;
332 unsigned long npages = dir_pages(dir);
333 struct page *page = NULL;
334 struct nilfs_inode_info *ei = NILFS_I(dir);
335 struct nilfs_dir_entry *de;
336
337 if (npages == 0)
338 goto out;
339
340 /* OFFSET_CACHE */
341 *res_page = NULL;
342
343 start = ei->i_dir_start_lookup;
344 if (start >= npages)
345 start = 0;
346 n = start;
347 do {
348 char *kaddr;
349
350 page = nilfs_get_page(dir, n);
351 if (!IS_ERR(page)) {
352 kaddr = page_address(page);
353 de = (struct nilfs_dir_entry *)kaddr;
354 kaddr += nilfs_last_byte(dir, n) - reclen;
355 while ((char *) de <= kaddr) {
356 if (de->rec_len == 0) {
357 nilfs_error(dir->i_sb,
358 "zero-length directory entry");
359 nilfs_put_page(page);
360 goto out;
361 }
362 if (nilfs_match(namelen, name, de))
363 goto found;
364 de = nilfs_next_entry(de);
365 }
366 nilfs_put_page(page);
367 }
368 if (++n >= npages)
369 n = 0;
370 /* next page is past the blocks we've got */
371 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
372 nilfs_error(dir->i_sb,
373 "dir %lu size %lld exceeds block count %llu",
374 dir->i_ino, dir->i_size,
375 (unsigned long long)dir->i_blocks);
376 goto out;
377 }
378 } while (n != start);
379out:
380 return NULL;
381
382found:
383 *res_page = page;
384 ei->i_dir_start_lookup = n;
385 return de;
386}
387
388struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
389{
390 struct page *page = nilfs_get_page(dir, 0);
391 struct nilfs_dir_entry *de = NULL;
392
393 if (!IS_ERR(page)) {
394 de = nilfs_next_entry(
395 (struct nilfs_dir_entry *)page_address(page));
396 *p = page;
397 }
398 return de;
399}
400
401ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
402{
403 ino_t res = 0;
404 struct nilfs_dir_entry *de;
405 struct page *page;
406
407 de = nilfs_find_entry(dir, qstr, &page);
408 if (de) {
409 res = le64_to_cpu(de->inode);
410 kunmap(page);
411 put_page(page);
412 }
413 return res;
414}
415
416/* Releases the page */
417void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
418 struct page *page, struct inode *inode)
419{
420 unsigned int from = (char *)de - (char *)page_address(page);
421 unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
422 struct address_space *mapping = page->mapping;
423 int err;
424
425 lock_page(page);
426 err = nilfs_prepare_chunk(page, from, to);
427 BUG_ON(err);
428 de->inode = cpu_to_le64(inode->i_ino);
429 nilfs_set_de_type(de, inode);
430 nilfs_commit_chunk(page, mapping, from, to);
431 nilfs_put_page(page);
432 dir->i_mtime = dir->i_ctime = current_time(dir);
433}
434
435/*
436 * Parent is locked.
437 */
438int nilfs_add_link(struct dentry *dentry, struct inode *inode)
439{
440 struct inode *dir = d_inode(dentry->d_parent);
441 const unsigned char *name = dentry->d_name.name;
442 int namelen = dentry->d_name.len;
443 unsigned int chunk_size = nilfs_chunk_size(dir);
444 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
445 unsigned short rec_len, name_len;
446 struct page *page = NULL;
447 struct nilfs_dir_entry *de;
448 unsigned long npages = dir_pages(dir);
449 unsigned long n;
450 char *kaddr;
451 unsigned int from, to;
452 int err;
453
454 /*
455 * We take care of directory expansion in the same loop.
456 * This code plays outside i_size, so it locks the page
457 * to protect that region.
458 */
459 for (n = 0; n <= npages; n++) {
460 char *dir_end;
461
462 page = nilfs_get_page(dir, n);
463 err = PTR_ERR(page);
464 if (IS_ERR(page))
465 goto out;
466 lock_page(page);
467 kaddr = page_address(page);
468 dir_end = kaddr + nilfs_last_byte(dir, n);
469 de = (struct nilfs_dir_entry *)kaddr;
470 kaddr += PAGE_SIZE - reclen;
471 while ((char *)de <= kaddr) {
472 if ((char *)de == dir_end) {
473 /* We hit i_size */
474 name_len = 0;
475 rec_len = chunk_size;
476 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
477 de->inode = 0;
478 goto got_it;
479 }
480 if (de->rec_len == 0) {
481 nilfs_error(dir->i_sb,
482 "zero-length directory entry");
483 err = -EIO;
484 goto out_unlock;
485 }
486 err = -EEXIST;
487 if (nilfs_match(namelen, name, de))
488 goto out_unlock;
489 name_len = NILFS_DIR_REC_LEN(de->name_len);
490 rec_len = nilfs_rec_len_from_disk(de->rec_len);
491 if (!de->inode && rec_len >= reclen)
492 goto got_it;
493 if (rec_len >= name_len + reclen)
494 goto got_it;
495 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
496 }
497 unlock_page(page);
498 nilfs_put_page(page);
499 }
500 BUG();
501 return -EINVAL;
502
503got_it:
504 from = (char *)de - (char *)page_address(page);
505 to = from + rec_len;
506 err = nilfs_prepare_chunk(page, from, to);
507 if (err)
508 goto out_unlock;
509 if (de->inode) {
510 struct nilfs_dir_entry *de1;
511
512 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
513 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
514 de->rec_len = nilfs_rec_len_to_disk(name_len);
515 de = de1;
516 }
517 de->name_len = namelen;
518 memcpy(de->name, name, namelen);
519 de->inode = cpu_to_le64(inode->i_ino);
520 nilfs_set_de_type(de, inode);
521 nilfs_commit_chunk(page, page->mapping, from, to);
522 dir->i_mtime = dir->i_ctime = current_time(dir);
523 nilfs_mark_inode_dirty(dir);
524 /* OFFSET_CACHE */
525out_put:
526 nilfs_put_page(page);
527out:
528 return err;
529out_unlock:
530 unlock_page(page);
531 goto out_put;
532}
533
534/*
535 * nilfs_delete_entry deletes a directory entry by merging it with the
536 * previous entry. Page is up-to-date. Releases the page.
537 */
538int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
539{
540 struct address_space *mapping = page->mapping;
541 struct inode *inode = mapping->host;
542 char *kaddr = page_address(page);
543 unsigned int from, to;
544 struct nilfs_dir_entry *de, *pde = NULL;
545 int err;
546
547 from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
548 to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
549 de = (struct nilfs_dir_entry *)(kaddr + from);
550
551 while ((char *)de < (char *)dir) {
552 if (de->rec_len == 0) {
553 nilfs_error(inode->i_sb,
554 "zero-length directory entry");
555 err = -EIO;
556 goto out;
557 }
558 pde = de;
559 de = nilfs_next_entry(de);
560 }
561 if (pde)
562 from = (char *)pde - (char *)page_address(page);
563 lock_page(page);
564 err = nilfs_prepare_chunk(page, from, to);
565 BUG_ON(err);
566 if (pde)
567 pde->rec_len = nilfs_rec_len_to_disk(to - from);
568 dir->inode = 0;
569 nilfs_commit_chunk(page, mapping, from, to);
570 inode->i_ctime = inode->i_mtime = current_time(inode);
571out:
572 nilfs_put_page(page);
573 return err;
574}
575
576/*
577 * Set the first fragment of directory.
578 */
579int nilfs_make_empty(struct inode *inode, struct inode *parent)
580{
581 struct address_space *mapping = inode->i_mapping;
582 struct page *page = grab_cache_page(mapping, 0);
583 unsigned int chunk_size = nilfs_chunk_size(inode);
584 struct nilfs_dir_entry *de;
585 int err;
586 void *kaddr;
587
588 if (!page)
589 return -ENOMEM;
590
591 err = nilfs_prepare_chunk(page, 0, chunk_size);
592 if (unlikely(err)) {
593 unlock_page(page);
594 goto fail;
595 }
596 kaddr = kmap_atomic(page);
597 memset(kaddr, 0, chunk_size);
598 de = (struct nilfs_dir_entry *)kaddr;
599 de->name_len = 1;
600 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
601 memcpy(de->name, ".\0\0", 4);
602 de->inode = cpu_to_le64(inode->i_ino);
603 nilfs_set_de_type(de, inode);
604
605 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
606 de->name_len = 2;
607 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
608 de->inode = cpu_to_le64(parent->i_ino);
609 memcpy(de->name, "..\0", 4);
610 nilfs_set_de_type(de, inode);
611 kunmap_atomic(kaddr);
612 nilfs_commit_chunk(page, mapping, 0, chunk_size);
613fail:
614 put_page(page);
615 return err;
616}
617
618/*
619 * routine to check that the specified directory is empty (for rmdir)
620 */
621int nilfs_empty_dir(struct inode *inode)
622{
623 struct page *page = NULL;
624 unsigned long i, npages = dir_pages(inode);
625
626 for (i = 0; i < npages; i++) {
627 char *kaddr;
628 struct nilfs_dir_entry *de;
629
630 page = nilfs_get_page(inode, i);
631 if (IS_ERR(page))
632 continue;
633
634 kaddr = page_address(page);
635 de = (struct nilfs_dir_entry *)kaddr;
636 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
637
638 while ((char *)de <= kaddr) {
639 if (de->rec_len == 0) {
640 nilfs_error(inode->i_sb,
641 "zero-length directory entry (kaddr=%p, de=%p)",
642 kaddr, de);
643 goto not_empty;
644 }
645 if (de->inode != 0) {
646 /* check for . and .. */
647 if (de->name[0] != '.')
648 goto not_empty;
649 if (de->name_len > 2)
650 goto not_empty;
651 if (de->name_len < 2) {
652 if (de->inode !=
653 cpu_to_le64(inode->i_ino))
654 goto not_empty;
655 } else if (de->name[1] != '.')
656 goto not_empty;
657 }
658 de = nilfs_next_entry(de);
659 }
660 nilfs_put_page(page);
661 }
662 return 1;
663
664not_empty:
665 nilfs_put_page(page);
666 return 0;
667}
668
669const struct file_operations nilfs_dir_operations = {
670 .llseek = generic_file_llseek,
671 .read = generic_read_dir,
672 .iterate_shared = nilfs_readdir,
673 .unlocked_ioctl = nilfs_ioctl,
674#ifdef CONFIG_COMPAT
675 .compat_ioctl = nilfs_compat_ioctl,
676#endif /* CONFIG_COMPAT */
677 .fsync = nilfs_sync_file,
678
679};
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * NILFS directory entry operations
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Modified for NILFS by Amagai Yoshiji.
8 */
9/*
10 * linux/fs/ext2/dir.c
11 *
12 * Copyright (C) 1992, 1993, 1994, 1995
13 * Remy Card (card@masi.ibp.fr)
14 * Laboratoire MASI - Institut Blaise Pascal
15 * Universite Pierre et Marie Curie (Paris VI)
16 *
17 * from
18 *
19 * linux/fs/minix/dir.c
20 *
21 * Copyright (C) 1991, 1992 Linus Torvalds
22 *
23 * ext2 directory handling functions
24 *
25 * Big-endian to little-endian byte-swapping/bitmaps by
26 * David S. Miller (davem@caip.rutgers.edu), 1995
27 *
28 * All code that works with directory layout had been switched to pagecache
29 * and moved here. AV
30 */
31
32#include <linux/pagemap.h>
33#include "nilfs.h"
34#include "page.h"
35
36static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
37{
38 unsigned int len = le16_to_cpu(dlen);
39
40#if (PAGE_SIZE >= 65536)
41 if (len == NILFS_MAX_REC_LEN)
42 return 1 << 16;
43#endif
44 return len;
45}
46
47static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
48{
49#if (PAGE_SIZE >= 65536)
50 if (len == (1 << 16))
51 return cpu_to_le16(NILFS_MAX_REC_LEN);
52
53 BUG_ON(len > (1 << 16));
54#endif
55 return cpu_to_le16(len);
56}
57
58/*
59 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
60 * more robust, but we have what we have
61 */
62static inline unsigned int nilfs_chunk_size(struct inode *inode)
63{
64 return inode->i_sb->s_blocksize;
65}
66
67/*
68 * Return the offset into page `page_nr' of the last valid
69 * byte in that page, plus one.
70 */
71static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
72{
73 u64 last_byte = inode->i_size;
74
75 last_byte -= page_nr << PAGE_SHIFT;
76 if (last_byte > PAGE_SIZE)
77 last_byte = PAGE_SIZE;
78 return last_byte;
79}
80
81static int nilfs_prepare_chunk(struct folio *folio, unsigned int from,
82 unsigned int to)
83{
84 loff_t pos = folio_pos(folio) + from;
85
86 return __block_write_begin(folio, pos, to - from, nilfs_get_block);
87}
88
89static void nilfs_commit_chunk(struct folio *folio,
90 struct address_space *mapping, size_t from, size_t to)
91{
92 struct inode *dir = mapping->host;
93 loff_t pos = folio_pos(folio) + from;
94 size_t copied, len = to - from;
95 unsigned int nr_dirty;
96 int err;
97
98 nr_dirty = nilfs_page_count_clean_buffers(folio, from, to);
99 copied = block_write_end(NULL, mapping, pos, len, len, folio, NULL);
100 if (pos + copied > dir->i_size)
101 i_size_write(dir, pos + copied);
102 if (IS_DIRSYNC(dir))
103 nilfs_set_transaction_flag(NILFS_TI_SYNC);
104 err = nilfs_set_file_dirty(dir, nr_dirty);
105 WARN_ON(err); /* do not happen */
106 folio_unlock(folio);
107}
108
109static bool nilfs_check_folio(struct folio *folio, char *kaddr)
110{
111 struct inode *dir = folio->mapping->host;
112 struct super_block *sb = dir->i_sb;
113 unsigned int chunk_size = nilfs_chunk_size(dir);
114 size_t offs, rec_len;
115 size_t limit = folio_size(folio);
116 struct nilfs_dir_entry *p;
117 char *error;
118
119 if (dir->i_size < folio_pos(folio) + limit) {
120 limit = dir->i_size - folio_pos(folio);
121 if (limit & (chunk_size - 1))
122 goto Ebadsize;
123 if (!limit)
124 goto out;
125 }
126 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
127 p = (struct nilfs_dir_entry *)(kaddr + offs);
128 rec_len = nilfs_rec_len_from_disk(p->rec_len);
129
130 if (rec_len < NILFS_DIR_REC_LEN(1))
131 goto Eshort;
132 if (rec_len & 3)
133 goto Ealign;
134 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
135 goto Enamelen;
136 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
137 goto Espan;
138 if (unlikely(p->inode &&
139 NILFS_PRIVATE_INODE(le64_to_cpu(p->inode))))
140 goto Einumber;
141 }
142 if (offs != limit)
143 goto Eend;
144out:
145 folio_set_checked(folio);
146 return true;
147
148 /* Too bad, we had an error */
149
150Ebadsize:
151 nilfs_error(sb,
152 "size of directory #%lu is not a multiple of chunk size",
153 dir->i_ino);
154 goto fail;
155Eshort:
156 error = "rec_len is smaller than minimal";
157 goto bad_entry;
158Ealign:
159 error = "unaligned directory entry";
160 goto bad_entry;
161Enamelen:
162 error = "rec_len is too small for name_len";
163 goto bad_entry;
164Espan:
165 error = "directory entry across blocks";
166 goto bad_entry;
167Einumber:
168 error = "disallowed inode number";
169bad_entry:
170 nilfs_error(sb,
171 "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%zd, name_len=%d",
172 dir->i_ino, error, (folio->index << PAGE_SHIFT) + offs,
173 (unsigned long)le64_to_cpu(p->inode),
174 rec_len, p->name_len);
175 goto fail;
176Eend:
177 p = (struct nilfs_dir_entry *)(kaddr + offs);
178 nilfs_error(sb,
179 "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
180 dir->i_ino, (folio->index << PAGE_SHIFT) + offs,
181 (unsigned long)le64_to_cpu(p->inode));
182fail:
183 return false;
184}
185
186static void *nilfs_get_folio(struct inode *dir, unsigned long n,
187 struct folio **foliop)
188{
189 struct address_space *mapping = dir->i_mapping;
190 struct folio *folio = read_mapping_folio(mapping, n, NULL);
191 void *kaddr;
192
193 if (IS_ERR(folio))
194 return folio;
195
196 kaddr = kmap_local_folio(folio, 0);
197 if (unlikely(!folio_test_checked(folio))) {
198 if (!nilfs_check_folio(folio, kaddr))
199 goto fail;
200 }
201
202 *foliop = folio;
203 return kaddr;
204
205fail:
206 folio_release_kmap(folio, kaddr);
207 return ERR_PTR(-EIO);
208}
209
210/*
211 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
212 *
213 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
214 */
215static int
216nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
217{
218 if (len != de->name_len)
219 return 0;
220 if (!de->inode)
221 return 0;
222 return !memcmp(name, de->name, len);
223}
224
225/*
226 * p is at least 6 bytes before the end of page
227 */
228static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
229{
230 return (struct nilfs_dir_entry *)((char *)p +
231 nilfs_rec_len_from_disk(p->rec_len));
232}
233
234static int nilfs_readdir(struct file *file, struct dir_context *ctx)
235{
236 loff_t pos = ctx->pos;
237 struct inode *inode = file_inode(file);
238 struct super_block *sb = inode->i_sb;
239 unsigned int offset = pos & ~PAGE_MASK;
240 unsigned long n = pos >> PAGE_SHIFT;
241 unsigned long npages = dir_pages(inode);
242
243 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
244 return 0;
245
246 for ( ; n < npages; n++, offset = 0) {
247 char *kaddr, *limit;
248 struct nilfs_dir_entry *de;
249 struct folio *folio;
250
251 kaddr = nilfs_get_folio(inode, n, &folio);
252 if (IS_ERR(kaddr)) {
253 nilfs_error(sb, "bad page in #%lu", inode->i_ino);
254 ctx->pos += PAGE_SIZE - offset;
255 return -EIO;
256 }
257 de = (struct nilfs_dir_entry *)(kaddr + offset);
258 limit = kaddr + nilfs_last_byte(inode, n) -
259 NILFS_DIR_REC_LEN(1);
260 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
261 if (de->rec_len == 0) {
262 nilfs_error(sb, "zero-length directory entry");
263 folio_release_kmap(folio, kaddr);
264 return -EIO;
265 }
266 if (de->inode) {
267 unsigned char t;
268
269 t = fs_ftype_to_dtype(de->file_type);
270
271 if (!dir_emit(ctx, de->name, de->name_len,
272 le64_to_cpu(de->inode), t)) {
273 folio_release_kmap(folio, kaddr);
274 return 0;
275 }
276 }
277 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
278 }
279 folio_release_kmap(folio, kaddr);
280 }
281 return 0;
282}
283
284/*
285 * nilfs_find_entry()
286 *
287 * Finds an entry in the specified directory with the wanted name. It
288 * returns the folio in which the entry was found, and the entry itself.
289 * The folio is mapped and unlocked. When the caller is finished with
290 * the entry, it should call folio_release_kmap().
291 *
292 * On failure, returns an error pointer and the caller should ignore foliop.
293 */
294struct nilfs_dir_entry *nilfs_find_entry(struct inode *dir,
295 const struct qstr *qstr, struct folio **foliop)
296{
297 const unsigned char *name = qstr->name;
298 int namelen = qstr->len;
299 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
300 unsigned long start, n;
301 unsigned long npages = dir_pages(dir);
302 struct nilfs_inode_info *ei = NILFS_I(dir);
303 struct nilfs_dir_entry *de;
304
305 if (npages == 0)
306 goto out;
307
308 start = ei->i_dir_start_lookup;
309 if (start >= npages)
310 start = 0;
311 n = start;
312 do {
313 char *kaddr = nilfs_get_folio(dir, n, foliop);
314
315 if (IS_ERR(kaddr))
316 return ERR_CAST(kaddr);
317
318 de = (struct nilfs_dir_entry *)kaddr;
319 kaddr += nilfs_last_byte(dir, n) - reclen;
320 while ((char *)de <= kaddr) {
321 if (de->rec_len == 0) {
322 nilfs_error(dir->i_sb,
323 "zero-length directory entry");
324 folio_release_kmap(*foliop, kaddr);
325 goto out;
326 }
327 if (nilfs_match(namelen, name, de))
328 goto found;
329 de = nilfs_next_entry(de);
330 }
331 folio_release_kmap(*foliop, kaddr);
332
333 if (++n >= npages)
334 n = 0;
335 /* next folio is past the blocks we've got */
336 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
337 nilfs_error(dir->i_sb,
338 "dir %lu size %lld exceeds block count %llu",
339 dir->i_ino, dir->i_size,
340 (unsigned long long)dir->i_blocks);
341 goto out;
342 }
343 } while (n != start);
344out:
345 return ERR_PTR(-ENOENT);
346
347found:
348 ei->i_dir_start_lookup = n;
349 return de;
350}
351
352struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop)
353{
354 struct folio *folio;
355 struct nilfs_dir_entry *de, *next_de;
356 size_t limit;
357 char *msg;
358
359 de = nilfs_get_folio(dir, 0, &folio);
360 if (IS_ERR(de))
361 return NULL;
362
363 limit = nilfs_last_byte(dir, 0); /* is a multiple of chunk size */
364 if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino ||
365 !nilfs_match(1, ".", de))) {
366 msg = "missing '.'";
367 goto fail;
368 }
369
370 next_de = nilfs_next_entry(de);
371 /*
372 * If "next_de" has not reached the end of the chunk, there is
373 * at least one more record. Check whether it matches "..".
374 */
375 if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) ||
376 !nilfs_match(2, "..", next_de))) {
377 msg = "missing '..'";
378 goto fail;
379 }
380 *foliop = folio;
381 return next_de;
382
383fail:
384 nilfs_error(dir->i_sb, "directory #%lu %s", dir->i_ino, msg);
385 folio_release_kmap(folio, de);
386 return NULL;
387}
388
389int nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr, ino_t *ino)
390{
391 struct nilfs_dir_entry *de;
392 struct folio *folio;
393
394 de = nilfs_find_entry(dir, qstr, &folio);
395 if (IS_ERR(de))
396 return PTR_ERR(de);
397
398 *ino = le64_to_cpu(de->inode);
399 folio_release_kmap(folio, de);
400 return 0;
401}
402
403int nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
404 struct folio *folio, struct inode *inode)
405{
406 size_t from = offset_in_folio(folio, de);
407 size_t to = from + nilfs_rec_len_from_disk(de->rec_len);
408 struct address_space *mapping = folio->mapping;
409 int err;
410
411 folio_lock(folio);
412 err = nilfs_prepare_chunk(folio, from, to);
413 if (unlikely(err)) {
414 folio_unlock(folio);
415 return err;
416 }
417 de->inode = cpu_to_le64(inode->i_ino);
418 de->file_type = fs_umode_to_ftype(inode->i_mode);
419 nilfs_commit_chunk(folio, mapping, from, to);
420 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
421 return 0;
422}
423
424/*
425 * Parent is locked.
426 */
427int nilfs_add_link(struct dentry *dentry, struct inode *inode)
428{
429 struct inode *dir = d_inode(dentry->d_parent);
430 const unsigned char *name = dentry->d_name.name;
431 int namelen = dentry->d_name.len;
432 unsigned int chunk_size = nilfs_chunk_size(dir);
433 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
434 unsigned short rec_len, name_len;
435 struct folio *folio = NULL;
436 struct nilfs_dir_entry *de;
437 unsigned long npages = dir_pages(dir);
438 unsigned long n;
439 size_t from, to;
440 int err;
441
442 /*
443 * We take care of directory expansion in the same loop.
444 * This code plays outside i_size, so it locks the folio
445 * to protect that region.
446 */
447 for (n = 0; n <= npages; n++) {
448 char *kaddr = nilfs_get_folio(dir, n, &folio);
449 char *dir_end;
450
451 if (IS_ERR(kaddr))
452 return PTR_ERR(kaddr);
453 folio_lock(folio);
454 dir_end = kaddr + nilfs_last_byte(dir, n);
455 de = (struct nilfs_dir_entry *)kaddr;
456 kaddr += folio_size(folio) - reclen;
457 while ((char *)de <= kaddr) {
458 if ((char *)de == dir_end) {
459 /* We hit i_size */
460 name_len = 0;
461 rec_len = chunk_size;
462 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
463 de->inode = 0;
464 goto got_it;
465 }
466 if (de->rec_len == 0) {
467 nilfs_error(dir->i_sb,
468 "zero-length directory entry");
469 err = -EIO;
470 goto out_unlock;
471 }
472 err = -EEXIST;
473 if (nilfs_match(namelen, name, de))
474 goto out_unlock;
475 name_len = NILFS_DIR_REC_LEN(de->name_len);
476 rec_len = nilfs_rec_len_from_disk(de->rec_len);
477 if (!de->inode && rec_len >= reclen)
478 goto got_it;
479 if (rec_len >= name_len + reclen)
480 goto got_it;
481 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
482 }
483 folio_unlock(folio);
484 folio_release_kmap(folio, kaddr);
485 }
486 BUG();
487 return -EINVAL;
488
489got_it:
490 from = offset_in_folio(folio, de);
491 to = from + rec_len;
492 err = nilfs_prepare_chunk(folio, from, to);
493 if (err)
494 goto out_unlock;
495 if (de->inode) {
496 struct nilfs_dir_entry *de1;
497
498 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
499 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
500 de->rec_len = nilfs_rec_len_to_disk(name_len);
501 de = de1;
502 }
503 de->name_len = namelen;
504 memcpy(de->name, name, namelen);
505 de->inode = cpu_to_le64(inode->i_ino);
506 de->file_type = fs_umode_to_ftype(inode->i_mode);
507 nilfs_commit_chunk(folio, folio->mapping, from, to);
508 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
509 nilfs_mark_inode_dirty(dir);
510 /* OFFSET_CACHE */
511out_put:
512 folio_release_kmap(folio, de);
513 return err;
514out_unlock:
515 folio_unlock(folio);
516 goto out_put;
517}
518
519/*
520 * nilfs_delete_entry deletes a directory entry by merging it with the
521 * previous entry. Folio is up-to-date.
522 */
523int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct folio *folio)
524{
525 struct address_space *mapping = folio->mapping;
526 struct inode *inode = mapping->host;
527 char *kaddr = (char *)((unsigned long)dir & ~(folio_size(folio) - 1));
528 size_t from, to;
529 struct nilfs_dir_entry *de, *pde = NULL;
530 int err;
531
532 from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
533 to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
534 de = (struct nilfs_dir_entry *)(kaddr + from);
535
536 while ((char *)de < (char *)dir) {
537 if (de->rec_len == 0) {
538 nilfs_error(inode->i_sb,
539 "zero-length directory entry");
540 err = -EIO;
541 goto out;
542 }
543 pde = de;
544 de = nilfs_next_entry(de);
545 }
546 if (pde)
547 from = (char *)pde - kaddr;
548 folio_lock(folio);
549 err = nilfs_prepare_chunk(folio, from, to);
550 if (unlikely(err)) {
551 folio_unlock(folio);
552 goto out;
553 }
554 if (pde)
555 pde->rec_len = nilfs_rec_len_to_disk(to - from);
556 dir->inode = 0;
557 nilfs_commit_chunk(folio, mapping, from, to);
558 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
559out:
560 return err;
561}
562
563/*
564 * Set the first fragment of directory.
565 */
566int nilfs_make_empty(struct inode *inode, struct inode *parent)
567{
568 struct address_space *mapping = inode->i_mapping;
569 struct folio *folio = filemap_grab_folio(mapping, 0);
570 unsigned int chunk_size = nilfs_chunk_size(inode);
571 struct nilfs_dir_entry *de;
572 int err;
573 void *kaddr;
574
575 if (IS_ERR(folio))
576 return PTR_ERR(folio);
577
578 err = nilfs_prepare_chunk(folio, 0, chunk_size);
579 if (unlikely(err)) {
580 folio_unlock(folio);
581 goto fail;
582 }
583 kaddr = kmap_local_folio(folio, 0);
584 memset(kaddr, 0, chunk_size);
585 de = (struct nilfs_dir_entry *)kaddr;
586 de->name_len = 1;
587 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
588 memcpy(de->name, ".\0\0", 4);
589 de->inode = cpu_to_le64(inode->i_ino);
590 de->file_type = fs_umode_to_ftype(inode->i_mode);
591
592 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
593 de->name_len = 2;
594 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
595 de->inode = cpu_to_le64(parent->i_ino);
596 memcpy(de->name, "..\0", 4);
597 de->file_type = fs_umode_to_ftype(inode->i_mode);
598 kunmap_local(kaddr);
599 nilfs_commit_chunk(folio, mapping, 0, chunk_size);
600fail:
601 folio_put(folio);
602 return err;
603}
604
605/*
606 * routine to check that the specified directory is empty (for rmdir)
607 */
608int nilfs_empty_dir(struct inode *inode)
609{
610 struct folio *folio = NULL;
611 char *kaddr;
612 unsigned long i, npages = dir_pages(inode);
613
614 for (i = 0; i < npages; i++) {
615 struct nilfs_dir_entry *de;
616
617 kaddr = nilfs_get_folio(inode, i, &folio);
618 if (IS_ERR(kaddr))
619 return 0;
620
621 de = (struct nilfs_dir_entry *)kaddr;
622 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
623
624 while ((char *)de <= kaddr) {
625 if (de->rec_len == 0) {
626 nilfs_error(inode->i_sb,
627 "zero-length directory entry (kaddr=%p, de=%p)",
628 kaddr, de);
629 goto not_empty;
630 }
631 if (de->inode != 0) {
632 /* check for . and .. */
633 if (de->name[0] != '.')
634 goto not_empty;
635 if (de->name_len > 2)
636 goto not_empty;
637 if (de->name_len < 2) {
638 if (de->inode !=
639 cpu_to_le64(inode->i_ino))
640 goto not_empty;
641 } else if (de->name[1] != '.')
642 goto not_empty;
643 }
644 de = nilfs_next_entry(de);
645 }
646 folio_release_kmap(folio, kaddr);
647 }
648 return 1;
649
650not_empty:
651 folio_release_kmap(folio, kaddr);
652 return 0;
653}
654
655const struct file_operations nilfs_dir_operations = {
656 .llseek = generic_file_llseek,
657 .read = generic_read_dir,
658 .iterate_shared = nilfs_readdir,
659 .unlocked_ioctl = nilfs_ioctl,
660#ifdef CONFIG_COMPAT
661 .compat_ioctl = nilfs_compat_ioctl,
662#endif /* CONFIG_COMPAT */
663 .fsync = nilfs_sync_file,
664
665};