2 * dir.c - NILFS directory entry operations
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>
25 * Copyright (C) 1992, 1993, 1994, 1995
26 * Remy Card (card@masi.ibp.fr)
27 * Laboratoire MASI - Institut Blaise Pascal
28 * Universite Pierre et Marie Curie (Paris VI)
32 * linux/fs/minix/dir.c
34 * Copyright (C) 1991, 1992 Linus Torvalds
36 * ext2 directory handling functions
38 * Big-endian to little-endian byte-swapping/bitmaps by
39 * David S. Miller (davem@caip.rutgers.edu), 1995
41 * All code that works with directory layout had been switched to pagecache
45 #include <linux/pagemap.h>
50 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
51 * more robust, but we have what we have
53 static inline unsigned nilfs_chunk_size(struct inode
*inode
)
55 return inode
->i_sb
->s_blocksize
;
58 static inline void nilfs_put_page(struct page
*page
)
61 page_cache_release(page
);
64 static inline unsigned long dir_pages(struct inode
*inode
)
66 return (inode
->i_size
+PAGE_CACHE_SIZE
-1)>>PAGE_CACHE_SHIFT
;
70 * Return the offset into page `page_nr' of the last valid
71 * byte in that page, plus one.
73 static unsigned nilfs_last_byte(struct inode
*inode
, unsigned long page_nr
)
75 unsigned last_byte
= inode
->i_size
;
77 last_byte
-= page_nr
<< PAGE_CACHE_SHIFT
;
78 if (last_byte
> PAGE_CACHE_SIZE
)
79 last_byte
= PAGE_CACHE_SIZE
;
83 static int nilfs_prepare_chunk(struct page
*page
, unsigned from
, unsigned to
)
85 loff_t pos
= page_offset(page
) + from
;
86 return __block_write_begin(page
, pos
, to
- from
, nilfs_get_block
);
89 static void nilfs_commit_chunk(struct page
*page
,
90 struct address_space
*mapping
,
91 unsigned from
, unsigned to
)
93 struct inode
*dir
= mapping
->host
;
94 loff_t pos
= page_offset(page
) + from
;
95 unsigned len
= to
- from
;
96 unsigned nr_dirty
, copied
;
99 nr_dirty
= nilfs_page_count_clean_buffers(page
, from
, to
);
100 copied
= block_write_end(NULL
, mapping
, pos
, len
, len
, page
, NULL
);
101 if (pos
+ copied
> dir
->i_size
)
102 i_size_write(dir
, pos
+ copied
);
104 nilfs_set_transaction_flag(NILFS_TI_SYNC
);
105 err
= nilfs_set_file_dirty(dir
, nr_dirty
);
106 WARN_ON(err
); /* do not happen */
110 static void nilfs_check_page(struct page
*page
)
112 struct inode
*dir
= page
->mapping
->host
;
113 struct super_block
*sb
= dir
->i_sb
;
114 unsigned chunk_size
= nilfs_chunk_size(dir
);
115 char *kaddr
= page_address(page
);
116 unsigned offs
, rec_len
;
117 unsigned limit
= PAGE_CACHE_SIZE
;
118 struct nilfs_dir_entry
*p
;
121 if ((dir
->i_size
>> PAGE_CACHE_SHIFT
) == page
->index
) {
122 limit
= dir
->i_size
& ~PAGE_CACHE_MASK
;
123 if (limit
& (chunk_size
- 1))
128 for (offs
= 0; offs
<= limit
- NILFS_DIR_REC_LEN(1); offs
+= rec_len
) {
129 p
= (struct nilfs_dir_entry
*)(kaddr
+ offs
);
130 rec_len
= nilfs_rec_len_from_disk(p
->rec_len
);
132 if (rec_len
< NILFS_DIR_REC_LEN(1))
136 if (rec_len
< NILFS_DIR_REC_LEN(p
->name_len
))
138 if (((offs
+ rec_len
- 1) ^ offs
) & ~(chunk_size
-1))
144 SetPageChecked(page
);
147 /* Too bad, we had an error */
150 nilfs_error(sb
, "nilfs_check_page",
151 "size of directory #%lu is not a multiple of chunk size",
156 error
= "rec_len is smaller than minimal";
159 error
= "unaligned directory entry";
162 error
= "rec_len is too small for name_len";
165 error
= "directory entry across blocks";
167 nilfs_error(sb
, "nilfs_check_page", "bad entry in directory #%lu: %s - "
168 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
169 dir
->i_ino
, error
, (page
->index
<<PAGE_CACHE_SHIFT
)+offs
,
170 (unsigned long) le64_to_cpu(p
->inode
),
171 rec_len
, p
->name_len
);
174 p
= (struct nilfs_dir_entry
*)(kaddr
+ offs
);
175 nilfs_error(sb
, "nilfs_check_page",
176 "entry in directory #%lu spans the page boundary"
177 "offset=%lu, inode=%lu",
178 dir
->i_ino
, (page
->index
<<PAGE_CACHE_SHIFT
)+offs
,
179 (unsigned long) le64_to_cpu(p
->inode
));
181 SetPageChecked(page
);
185 static struct page
*nilfs_get_page(struct inode
*dir
, unsigned long n
)
187 struct address_space
*mapping
= dir
->i_mapping
;
188 struct page
*page
= read_mapping_page(mapping
, n
, NULL
);
192 if (!PageChecked(page
))
193 nilfs_check_page(page
);
200 nilfs_put_page(page
);
201 return ERR_PTR(-EIO
);
205 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
207 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
210 nilfs_match(int len
, const unsigned char *name
, struct nilfs_dir_entry
*de
)
212 if (len
!= de
->name_len
)
216 return !memcmp(name
, de
->name
, len
);
220 * p is at least 6 bytes before the end of page
222 static struct nilfs_dir_entry
*nilfs_next_entry(struct nilfs_dir_entry
*p
)
224 return (struct nilfs_dir_entry
*)((char *)p
+
225 nilfs_rec_len_from_disk(p
->rec_len
));
229 nilfs_filetype_table
[NILFS_FT_MAX
] = {
230 [NILFS_FT_UNKNOWN
] = DT_UNKNOWN
,
231 [NILFS_FT_REG_FILE
] = DT_REG
,
232 [NILFS_FT_DIR
] = DT_DIR
,
233 [NILFS_FT_CHRDEV
] = DT_CHR
,
234 [NILFS_FT_BLKDEV
] = DT_BLK
,
235 [NILFS_FT_FIFO
] = DT_FIFO
,
236 [NILFS_FT_SOCK
] = DT_SOCK
,
237 [NILFS_FT_SYMLINK
] = DT_LNK
,
242 nilfs_type_by_mode
[S_IFMT
>> S_SHIFT
] = {
243 [S_IFREG
>> S_SHIFT
] = NILFS_FT_REG_FILE
,
244 [S_IFDIR
>> S_SHIFT
] = NILFS_FT_DIR
,
245 [S_IFCHR
>> S_SHIFT
] = NILFS_FT_CHRDEV
,
246 [S_IFBLK
>> S_SHIFT
] = NILFS_FT_BLKDEV
,
247 [S_IFIFO
>> S_SHIFT
] = NILFS_FT_FIFO
,
248 [S_IFSOCK
>> S_SHIFT
] = NILFS_FT_SOCK
,
249 [S_IFLNK
>> S_SHIFT
] = NILFS_FT_SYMLINK
,
252 static void nilfs_set_de_type(struct nilfs_dir_entry
*de
, struct inode
*inode
)
254 umode_t mode
= inode
->i_mode
;
256 de
->file_type
= nilfs_type_by_mode
[(mode
& S_IFMT
)>>S_SHIFT
];
259 static int nilfs_readdir(struct file
*file
, struct dir_context
*ctx
)
261 loff_t pos
= ctx
->pos
;
262 struct inode
*inode
= file_inode(file
);
263 struct super_block
*sb
= inode
->i_sb
;
264 unsigned int offset
= pos
& ~PAGE_CACHE_MASK
;
265 unsigned long n
= pos
>> PAGE_CACHE_SHIFT
;
266 unsigned long npages
= dir_pages(inode
);
267 /* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */
269 if (pos
> inode
->i_size
- NILFS_DIR_REC_LEN(1))
272 for ( ; n
< npages
; n
++, offset
= 0) {
274 struct nilfs_dir_entry
*de
;
275 struct page
*page
= nilfs_get_page(inode
, n
);
278 nilfs_error(sb
, __func__
, "bad page in #%lu",
280 ctx
->pos
+= PAGE_CACHE_SIZE
- offset
;
283 kaddr
= page_address(page
);
284 de
= (struct nilfs_dir_entry
*)(kaddr
+ offset
);
285 limit
= kaddr
+ nilfs_last_byte(inode
, n
) -
286 NILFS_DIR_REC_LEN(1);
287 for ( ; (char *)de
<= limit
; de
= nilfs_next_entry(de
)) {
288 if (de
->rec_len
== 0) {
289 nilfs_error(sb
, __func__
,
290 "zero-length directory entry");
291 nilfs_put_page(page
);
297 if (de
->file_type
< NILFS_FT_MAX
)
298 t
= nilfs_filetype_table
[de
->file_type
];
302 if (!dir_emit(ctx
, de
->name
, de
->name_len
,
303 le64_to_cpu(de
->inode
), t
)) {
304 nilfs_put_page(page
);
308 ctx
->pos
+= nilfs_rec_len_from_disk(de
->rec_len
);
310 nilfs_put_page(page
);
318 * finds an entry in the specified directory with the wanted name. It
319 * returns the page in which the entry was found, and the entry itself
320 * (as a parameter - res_dir). Page is returned mapped and unlocked.
321 * Entry is guaranteed to be valid.
323 struct nilfs_dir_entry
*
324 nilfs_find_entry(struct inode
*dir
, const struct qstr
*qstr
,
325 struct page
**res_page
)
327 const unsigned char *name
= qstr
->name
;
328 int namelen
= qstr
->len
;
329 unsigned reclen
= NILFS_DIR_REC_LEN(namelen
);
330 unsigned long start
, n
;
331 unsigned long npages
= dir_pages(dir
);
332 struct page
*page
= NULL
;
333 struct nilfs_inode_info
*ei
= NILFS_I(dir
);
334 struct nilfs_dir_entry
*de
;
342 start
= ei
->i_dir_start_lookup
;
348 page
= nilfs_get_page(dir
, n
);
350 kaddr
= page_address(page
);
351 de
= (struct nilfs_dir_entry
*)kaddr
;
352 kaddr
+= nilfs_last_byte(dir
, n
) - reclen
;
353 while ((char *) de
<= kaddr
) {
354 if (de
->rec_len
== 0) {
355 nilfs_error(dir
->i_sb
, __func__
,
356 "zero-length directory entry");
357 nilfs_put_page(page
);
360 if (nilfs_match(namelen
, name
, de
))
362 de
= nilfs_next_entry(de
);
364 nilfs_put_page(page
);
368 /* next page is past the blocks we've got */
369 if (unlikely(n
> (dir
->i_blocks
>> (PAGE_CACHE_SHIFT
- 9)))) {
370 nilfs_error(dir
->i_sb
, __func__
,
371 "dir %lu size %lld exceeds block count %llu",
372 dir
->i_ino
, dir
->i_size
,
373 (unsigned long long)dir
->i_blocks
);
376 } while (n
!= start
);
382 ei
->i_dir_start_lookup
= n
;
386 struct nilfs_dir_entry
*nilfs_dotdot(struct inode
*dir
, struct page
**p
)
388 struct page
*page
= nilfs_get_page(dir
, 0);
389 struct nilfs_dir_entry
*de
= NULL
;
392 de
= nilfs_next_entry(
393 (struct nilfs_dir_entry
*)page_address(page
));
399 ino_t
nilfs_inode_by_name(struct inode
*dir
, const struct qstr
*qstr
)
402 struct nilfs_dir_entry
*de
;
405 de
= nilfs_find_entry(dir
, qstr
, &page
);
407 res
= le64_to_cpu(de
->inode
);
409 page_cache_release(page
);
414 /* Releases the page */
415 void nilfs_set_link(struct inode
*dir
, struct nilfs_dir_entry
*de
,
416 struct page
*page
, struct inode
*inode
)
418 unsigned from
= (char *) de
- (char *) page_address(page
);
419 unsigned to
= from
+ nilfs_rec_len_from_disk(de
->rec_len
);
420 struct address_space
*mapping
= page
->mapping
;
424 err
= nilfs_prepare_chunk(page
, from
, to
);
426 de
->inode
= cpu_to_le64(inode
->i_ino
);
427 nilfs_set_de_type(de
, inode
);
428 nilfs_commit_chunk(page
, mapping
, from
, to
);
429 nilfs_put_page(page
);
430 dir
->i_mtime
= dir
->i_ctime
= CURRENT_TIME
;
436 int nilfs_add_link(struct dentry
*dentry
, struct inode
*inode
)
438 struct inode
*dir
= dentry
->d_parent
->d_inode
;
439 const unsigned char *name
= dentry
->d_name
.name
;
440 int namelen
= dentry
->d_name
.len
;
441 unsigned chunk_size
= nilfs_chunk_size(dir
);
442 unsigned reclen
= NILFS_DIR_REC_LEN(namelen
);
443 unsigned short rec_len
, name_len
;
444 struct page
*page
= NULL
;
445 struct nilfs_dir_entry
*de
;
446 unsigned long npages
= dir_pages(dir
);
453 * We take care of directory expansion in the same loop.
454 * This code plays outside i_size, so it locks the page
455 * to protect that region.
457 for (n
= 0; n
<= npages
; n
++) {
460 page
= nilfs_get_page(dir
, n
);
465 kaddr
= page_address(page
);
466 dir_end
= kaddr
+ nilfs_last_byte(dir
, n
);
467 de
= (struct nilfs_dir_entry
*)kaddr
;
468 kaddr
+= PAGE_CACHE_SIZE
- reclen
;
469 while ((char *)de
<= kaddr
) {
470 if ((char *)de
== dir_end
) {
473 rec_len
= chunk_size
;
474 de
->rec_len
= nilfs_rec_len_to_disk(chunk_size
);
478 if (de
->rec_len
== 0) {
479 nilfs_error(dir
->i_sb
, __func__
,
480 "zero-length directory entry");
485 if (nilfs_match(namelen
, name
, de
))
487 name_len
= NILFS_DIR_REC_LEN(de
->name_len
);
488 rec_len
= nilfs_rec_len_from_disk(de
->rec_len
);
489 if (!de
->inode
&& rec_len
>= reclen
)
491 if (rec_len
>= name_len
+ reclen
)
493 de
= (struct nilfs_dir_entry
*)((char *)de
+ rec_len
);
496 nilfs_put_page(page
);
502 from
= (char *)de
- (char *)page_address(page
);
504 err
= nilfs_prepare_chunk(page
, from
, to
);
508 struct nilfs_dir_entry
*de1
;
510 de1
= (struct nilfs_dir_entry
*)((char *)de
+ name_len
);
511 de1
->rec_len
= nilfs_rec_len_to_disk(rec_len
- name_len
);
512 de
->rec_len
= nilfs_rec_len_to_disk(name_len
);
515 de
->name_len
= namelen
;
516 memcpy(de
->name
, name
, namelen
);
517 de
->inode
= cpu_to_le64(inode
->i_ino
);
518 nilfs_set_de_type(de
, inode
);
519 nilfs_commit_chunk(page
, page
->mapping
, from
, to
);
520 dir
->i_mtime
= dir
->i_ctime
= CURRENT_TIME
;
521 nilfs_mark_inode_dirty(dir
);
524 nilfs_put_page(page
);
533 * nilfs_delete_entry deletes a directory entry by merging it with the
534 * previous entry. Page is up-to-date. Releases the page.
536 int nilfs_delete_entry(struct nilfs_dir_entry
*dir
, struct page
*page
)
538 struct address_space
*mapping
= page
->mapping
;
539 struct inode
*inode
= mapping
->host
;
540 char *kaddr
= page_address(page
);
541 unsigned from
= ((char *)dir
- kaddr
) & ~(nilfs_chunk_size(inode
) - 1);
542 unsigned to
= ((char *)dir
- kaddr
) +
543 nilfs_rec_len_from_disk(dir
->rec_len
);
544 struct nilfs_dir_entry
*pde
= NULL
;
545 struct nilfs_dir_entry
*de
= (struct nilfs_dir_entry
*)(kaddr
+ from
);
548 while ((char *)de
< (char *)dir
) {
549 if (de
->rec_len
== 0) {
550 nilfs_error(inode
->i_sb
, __func__
,
551 "zero-length directory entry");
556 de
= nilfs_next_entry(de
);
559 from
= (char *)pde
- (char *)page_address(page
);
561 err
= nilfs_prepare_chunk(page
, from
, to
);
564 pde
->rec_len
= nilfs_rec_len_to_disk(to
- from
);
566 nilfs_commit_chunk(page
, mapping
, from
, to
);
567 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
569 nilfs_put_page(page
);
574 * Set the first fragment of directory.
576 int nilfs_make_empty(struct inode
*inode
, struct inode
*parent
)
578 struct address_space
*mapping
= inode
->i_mapping
;
579 struct page
*page
= grab_cache_page(mapping
, 0);
580 unsigned chunk_size
= nilfs_chunk_size(inode
);
581 struct nilfs_dir_entry
*de
;
588 err
= nilfs_prepare_chunk(page
, 0, chunk_size
);
593 kaddr
= kmap_atomic(page
);
594 memset(kaddr
, 0, chunk_size
);
595 de
= (struct nilfs_dir_entry
*)kaddr
;
597 de
->rec_len
= nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
598 memcpy(de
->name
, ".\0\0", 4);
599 de
->inode
= cpu_to_le64(inode
->i_ino
);
600 nilfs_set_de_type(de
, inode
);
602 de
= (struct nilfs_dir_entry
*)(kaddr
+ NILFS_DIR_REC_LEN(1));
604 de
->rec_len
= nilfs_rec_len_to_disk(chunk_size
- NILFS_DIR_REC_LEN(1));
605 de
->inode
= cpu_to_le64(parent
->i_ino
);
606 memcpy(de
->name
, "..\0", 4);
607 nilfs_set_de_type(de
, inode
);
608 kunmap_atomic(kaddr
);
609 nilfs_commit_chunk(page
, mapping
, 0, chunk_size
);
611 page_cache_release(page
);
616 * routine to check that the specified directory is empty (for rmdir)
618 int nilfs_empty_dir(struct inode
*inode
)
620 struct page
*page
= NULL
;
621 unsigned long i
, npages
= dir_pages(inode
);
623 for (i
= 0; i
< npages
; i
++) {
625 struct nilfs_dir_entry
*de
;
627 page
= nilfs_get_page(inode
, i
);
631 kaddr
= page_address(page
);
632 de
= (struct nilfs_dir_entry
*)kaddr
;
633 kaddr
+= nilfs_last_byte(inode
, i
) - NILFS_DIR_REC_LEN(1);
635 while ((char *)de
<= kaddr
) {
636 if (de
->rec_len
== 0) {
637 nilfs_error(inode
->i_sb
, __func__
,
638 "zero-length directory entry "
639 "(kaddr=%p, de=%p)\n", kaddr
, de
);
642 if (de
->inode
!= 0) {
643 /* check for . and .. */
644 if (de
->name
[0] != '.')
646 if (de
->name_len
> 2)
648 if (de
->name_len
< 2) {
650 cpu_to_le64(inode
->i_ino
))
652 } else if (de
->name
[1] != '.')
655 de
= nilfs_next_entry(de
);
657 nilfs_put_page(page
);
662 nilfs_put_page(page
);
666 const struct file_operations nilfs_dir_operations
= {
667 .llseek
= generic_file_llseek
,
668 .read
= generic_read_dir
,
669 .iterate
= nilfs_readdir
,
670 .unlocked_ioctl
= nilfs_ioctl
,
672 .compat_ioctl
= nilfs_compat_ioctl
,
673 #endif /* CONFIG_COMPAT */
674 .fsync
= nilfs_sync_file
,