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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 unsigned int 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->page, 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->page, from, to);
99 copied = block_write_end(NULL, mapping, pos, len, len, &folio->page, 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 }
139 if (offs != limit)
140 goto Eend;
141out:
142 folio_set_checked(folio);
143 return true;
144
145 /* Too bad, we had an error */
146
147Ebadsize:
148 nilfs_error(sb,
149 "size of directory #%lu is not a multiple of chunk size",
150 dir->i_ino);
151 goto fail;
152Eshort:
153 error = "rec_len is smaller than minimal";
154 goto bad_entry;
155Ealign:
156 error = "unaligned directory entry";
157 goto bad_entry;
158Enamelen:
159 error = "rec_len is too small for name_len";
160 goto bad_entry;
161Espan:
162 error = "directory entry across blocks";
163bad_entry:
164 nilfs_error(sb,
165 "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%zd, name_len=%d",
166 dir->i_ino, error, (folio->index << PAGE_SHIFT) + offs,
167 (unsigned long)le64_to_cpu(p->inode),
168 rec_len, p->name_len);
169 goto fail;
170Eend:
171 p = (struct nilfs_dir_entry *)(kaddr + offs);
172 nilfs_error(sb,
173 "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
174 dir->i_ino, (folio->index << PAGE_SHIFT) + offs,
175 (unsigned long)le64_to_cpu(p->inode));
176fail:
177 folio_set_error(folio);
178 return false;
179}
180
181static void *nilfs_get_folio(struct inode *dir, unsigned long n,
182 struct folio **foliop)
183{
184 struct address_space *mapping = dir->i_mapping;
185 struct folio *folio = read_mapping_folio(mapping, n, NULL);
186 void *kaddr;
187
188 if (IS_ERR(folio))
189 return folio;
190
191 kaddr = kmap_local_folio(folio, 0);
192 if (unlikely(!folio_test_checked(folio))) {
193 if (!nilfs_check_folio(folio, kaddr))
194 goto fail;
195 }
196
197 *foliop = folio;
198 return kaddr;
199
200fail:
201 folio_release_kmap(folio, kaddr);
202 return ERR_PTR(-EIO);
203}
204
205/*
206 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
207 *
208 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
209 */
210static int
211nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
212{
213 if (len != de->name_len)
214 return 0;
215 if (!de->inode)
216 return 0;
217 return !memcmp(name, de->name, len);
218}
219
220/*
221 * p is at least 6 bytes before the end of page
222 */
223static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
224{
225 return (struct nilfs_dir_entry *)((char *)p +
226 nilfs_rec_len_from_disk(p->rec_len));
227}
228
229static unsigned char
230nilfs_filetype_table[NILFS_FT_MAX] = {
231 [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
232 [NILFS_FT_REG_FILE] = DT_REG,
233 [NILFS_FT_DIR] = DT_DIR,
234 [NILFS_FT_CHRDEV] = DT_CHR,
235 [NILFS_FT_BLKDEV] = DT_BLK,
236 [NILFS_FT_FIFO] = DT_FIFO,
237 [NILFS_FT_SOCK] = DT_SOCK,
238 [NILFS_FT_SYMLINK] = DT_LNK,
239};
240
241#define S_SHIFT 12
242static unsigned char
243nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
244 [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
245 [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
246 [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
247 [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
248 [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
249 [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
250 [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
251};
252
253static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
254{
255 umode_t mode = inode->i_mode;
256
257 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
258}
259
260static int nilfs_readdir(struct file *file, struct dir_context *ctx)
261{
262 loff_t pos = ctx->pos;
263 struct inode *inode = file_inode(file);
264 struct super_block *sb = inode->i_sb;
265 unsigned int offset = pos & ~PAGE_MASK;
266 unsigned long n = pos >> PAGE_SHIFT;
267 unsigned long npages = dir_pages(inode);
268
269 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
270 return 0;
271
272 for ( ; n < npages; n++, offset = 0) {
273 char *kaddr, *limit;
274 struct nilfs_dir_entry *de;
275 struct folio *folio;
276
277 kaddr = nilfs_get_folio(inode, n, &folio);
278 if (IS_ERR(kaddr)) {
279 nilfs_error(sb, "bad page in #%lu", inode->i_ino);
280 ctx->pos += PAGE_SIZE - offset;
281 return -EIO;
282 }
283 de = (struct nilfs_dir_entry *)(kaddr + offset);
284 limit = kaddr + nilfs_last_byte(inode, n) -
285 NILFS_DIR_REC_LEN(1);
286 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
287 if (de->rec_len == 0) {
288 nilfs_error(sb, "zero-length directory entry");
289 folio_release_kmap(folio, kaddr);
290 return -EIO;
291 }
292 if (de->inode) {
293 unsigned char t;
294
295 if (de->file_type < NILFS_FT_MAX)
296 t = nilfs_filetype_table[de->file_type];
297 else
298 t = DT_UNKNOWN;
299
300 if (!dir_emit(ctx, de->name, de->name_len,
301 le64_to_cpu(de->inode), t)) {
302 folio_release_kmap(folio, kaddr);
303 return 0;
304 }
305 }
306 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
307 }
308 folio_release_kmap(folio, kaddr);
309 }
310 return 0;
311}
312
313/*
314 * nilfs_find_entry()
315 *
316 * Finds an entry in the specified directory with the wanted name. It
317 * returns the folio in which the entry was found, and the entry itself.
318 * The folio is mapped and unlocked. When the caller is finished with
319 * the entry, it should call folio_release_kmap().
320 *
321 * On failure, returns NULL and the caller should ignore foliop.
322 */
323struct nilfs_dir_entry *nilfs_find_entry(struct inode *dir,
324 const struct qstr *qstr, struct folio **foliop)
325{
326 const unsigned char *name = qstr->name;
327 int namelen = qstr->len;
328 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
329 unsigned long start, n;
330 unsigned long npages = dir_pages(dir);
331 struct nilfs_inode_info *ei = NILFS_I(dir);
332 struct nilfs_dir_entry *de;
333
334 if (npages == 0)
335 goto out;
336
337 start = ei->i_dir_start_lookup;
338 if (start >= npages)
339 start = 0;
340 n = start;
341 do {
342 char *kaddr = nilfs_get_folio(dir, n, foliop);
343
344 if (!IS_ERR(kaddr)) {
345 de = (struct nilfs_dir_entry *)kaddr;
346 kaddr += nilfs_last_byte(dir, n) - reclen;
347 while ((char *) de <= kaddr) {
348 if (de->rec_len == 0) {
349 nilfs_error(dir->i_sb,
350 "zero-length directory entry");
351 folio_release_kmap(*foliop, kaddr);
352 goto out;
353 }
354 if (nilfs_match(namelen, name, de))
355 goto found;
356 de = nilfs_next_entry(de);
357 }
358 folio_release_kmap(*foliop, kaddr);
359 }
360 if (++n >= npages)
361 n = 0;
362 /* next folio is past the blocks we've got */
363 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
364 nilfs_error(dir->i_sb,
365 "dir %lu size %lld exceeds block count %llu",
366 dir->i_ino, dir->i_size,
367 (unsigned long long)dir->i_blocks);
368 goto out;
369 }
370 } while (n != start);
371out:
372 return NULL;
373
374found:
375 ei->i_dir_start_lookup = n;
376 return de;
377}
378
379struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop)
380{
381 struct nilfs_dir_entry *de = nilfs_get_folio(dir, 0, foliop);
382
383 if (IS_ERR(de))
384 return NULL;
385 return nilfs_next_entry(de);
386}
387
388ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
389{
390 ino_t res = 0;
391 struct nilfs_dir_entry *de;
392 struct folio *folio;
393
394 de = nilfs_find_entry(dir, qstr, &folio);
395 if (de) {
396 res = le64_to_cpu(de->inode);
397 folio_release_kmap(folio, de);
398 }
399 return res;
400}
401
402void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
403 struct folio *folio, struct inode *inode)
404{
405 size_t from = offset_in_folio(folio, de);
406 size_t to = from + nilfs_rec_len_from_disk(de->rec_len);
407 struct address_space *mapping = folio->mapping;
408 int err;
409
410 folio_lock(folio);
411 err = nilfs_prepare_chunk(folio, from, to);
412 BUG_ON(err);
413 de->inode = cpu_to_le64(inode->i_ino);
414 nilfs_set_de_type(de, inode);
415 nilfs_commit_chunk(folio, mapping, from, to);
416 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
417}
418
419/*
420 * Parent is locked.
421 */
422int nilfs_add_link(struct dentry *dentry, struct inode *inode)
423{
424 struct inode *dir = d_inode(dentry->d_parent);
425 const unsigned char *name = dentry->d_name.name;
426 int namelen = dentry->d_name.len;
427 unsigned int chunk_size = nilfs_chunk_size(dir);
428 unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
429 unsigned short rec_len, name_len;
430 struct folio *folio = NULL;
431 struct nilfs_dir_entry *de;
432 unsigned long npages = dir_pages(dir);
433 unsigned long n;
434 size_t from, to;
435 int err;
436
437 /*
438 * We take care of directory expansion in the same loop.
439 * This code plays outside i_size, so it locks the folio
440 * to protect that region.
441 */
442 for (n = 0; n <= npages; n++) {
443 char *kaddr = nilfs_get_folio(dir, n, &folio);
444 char *dir_end;
445
446 if (IS_ERR(kaddr))
447 return PTR_ERR(kaddr);
448 folio_lock(folio);
449 dir_end = kaddr + nilfs_last_byte(dir, n);
450 de = (struct nilfs_dir_entry *)kaddr;
451 kaddr += folio_size(folio) - reclen;
452 while ((char *)de <= kaddr) {
453 if ((char *)de == dir_end) {
454 /* We hit i_size */
455 name_len = 0;
456 rec_len = chunk_size;
457 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
458 de->inode = 0;
459 goto got_it;
460 }
461 if (de->rec_len == 0) {
462 nilfs_error(dir->i_sb,
463 "zero-length directory entry");
464 err = -EIO;
465 goto out_unlock;
466 }
467 err = -EEXIST;
468 if (nilfs_match(namelen, name, de))
469 goto out_unlock;
470 name_len = NILFS_DIR_REC_LEN(de->name_len);
471 rec_len = nilfs_rec_len_from_disk(de->rec_len);
472 if (!de->inode && rec_len >= reclen)
473 goto got_it;
474 if (rec_len >= name_len + reclen)
475 goto got_it;
476 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
477 }
478 folio_unlock(folio);
479 folio_release_kmap(folio, kaddr);
480 }
481 BUG();
482 return -EINVAL;
483
484got_it:
485 from = offset_in_folio(folio, de);
486 to = from + rec_len;
487 err = nilfs_prepare_chunk(folio, from, to);
488 if (err)
489 goto out_unlock;
490 if (de->inode) {
491 struct nilfs_dir_entry *de1;
492
493 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
494 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
495 de->rec_len = nilfs_rec_len_to_disk(name_len);
496 de = de1;
497 }
498 de->name_len = namelen;
499 memcpy(de->name, name, namelen);
500 de->inode = cpu_to_le64(inode->i_ino);
501 nilfs_set_de_type(de, inode);
502 nilfs_commit_chunk(folio, folio->mapping, from, to);
503 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
504 nilfs_mark_inode_dirty(dir);
505 /* OFFSET_CACHE */
506out_put:
507 folio_release_kmap(folio, de);
508 return err;
509out_unlock:
510 folio_unlock(folio);
511 goto out_put;
512}
513
514/*
515 * nilfs_delete_entry deletes a directory entry by merging it with the
516 * previous entry. Folio is up-to-date.
517 */
518int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct folio *folio)
519{
520 struct address_space *mapping = folio->mapping;
521 struct inode *inode = mapping->host;
522 char *kaddr = (char *)((unsigned long)dir & ~(folio_size(folio) - 1));
523 size_t from, to;
524 struct nilfs_dir_entry *de, *pde = NULL;
525 int err;
526
527 from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
528 to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
529 de = (struct nilfs_dir_entry *)(kaddr + from);
530
531 while ((char *)de < (char *)dir) {
532 if (de->rec_len == 0) {
533 nilfs_error(inode->i_sb,
534 "zero-length directory entry");
535 err = -EIO;
536 goto out;
537 }
538 pde = de;
539 de = nilfs_next_entry(de);
540 }
541 if (pde)
542 from = (char *)pde - kaddr;
543 folio_lock(folio);
544 err = nilfs_prepare_chunk(folio, from, to);
545 BUG_ON(err);
546 if (pde)
547 pde->rec_len = nilfs_rec_len_to_disk(to - from);
548 dir->inode = 0;
549 nilfs_commit_chunk(folio, mapping, from, to);
550 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
551out:
552 return err;
553}
554
555/*
556 * Set the first fragment of directory.
557 */
558int nilfs_make_empty(struct inode *inode, struct inode *parent)
559{
560 struct address_space *mapping = inode->i_mapping;
561 struct folio *folio = filemap_grab_folio(mapping, 0);
562 unsigned int chunk_size = nilfs_chunk_size(inode);
563 struct nilfs_dir_entry *de;
564 int err;
565 void *kaddr;
566
567 if (IS_ERR(folio))
568 return PTR_ERR(folio);
569
570 err = nilfs_prepare_chunk(folio, 0, chunk_size);
571 if (unlikely(err)) {
572 folio_unlock(folio);
573 goto fail;
574 }
575 kaddr = kmap_local_folio(folio, 0);
576 memset(kaddr, 0, chunk_size);
577 de = (struct nilfs_dir_entry *)kaddr;
578 de->name_len = 1;
579 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
580 memcpy(de->name, ".\0\0", 4);
581 de->inode = cpu_to_le64(inode->i_ino);
582 nilfs_set_de_type(de, inode);
583
584 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
585 de->name_len = 2;
586 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
587 de->inode = cpu_to_le64(parent->i_ino);
588 memcpy(de->name, "..\0", 4);
589 nilfs_set_de_type(de, inode);
590 kunmap_local(kaddr);
591 nilfs_commit_chunk(folio, mapping, 0, chunk_size);
592fail:
593 folio_put(folio);
594 return err;
595}
596
597/*
598 * routine to check that the specified directory is empty (for rmdir)
599 */
600int nilfs_empty_dir(struct inode *inode)
601{
602 struct folio *folio = NULL;
603 char *kaddr;
604 unsigned long i, npages = dir_pages(inode);
605
606 for (i = 0; i < npages; i++) {
607 struct nilfs_dir_entry *de;
608
609 kaddr = nilfs_get_folio(inode, i, &folio);
610 if (IS_ERR(kaddr))
611 continue;
612
613 de = (struct nilfs_dir_entry *)kaddr;
614 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
615
616 while ((char *)de <= kaddr) {
617 if (de->rec_len == 0) {
618 nilfs_error(inode->i_sb,
619 "zero-length directory entry (kaddr=%p, de=%p)",
620 kaddr, de);
621 goto not_empty;
622 }
623 if (de->inode != 0) {
624 /* check for . and .. */
625 if (de->name[0] != '.')
626 goto not_empty;
627 if (de->name_len > 2)
628 goto not_empty;
629 if (de->name_len < 2) {
630 if (de->inode !=
631 cpu_to_le64(inode->i_ino))
632 goto not_empty;
633 } else if (de->name[1] != '.')
634 goto not_empty;
635 }
636 de = nilfs_next_entry(de);
637 }
638 folio_release_kmap(folio, kaddr);
639 }
640 return 1;
641
642not_empty:
643 folio_release_kmap(folio, kaddr);
644 return 0;
645}
646
647const struct file_operations nilfs_dir_operations = {
648 .llseek = generic_file_llseek,
649 .read = generic_read_dir,
650 .iterate_shared = nilfs_readdir,
651 .unlocked_ioctl = nilfs_ioctl,
652#ifdef CONFIG_COMPAT
653 .compat_ioctl = nilfs_compat_ioctl,
654#endif /* CONFIG_COMPAT */
655 .fsync = nilfs_sync_file,
656
657};
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};