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 * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>
21 * Copyright (C) 1992, 1993, 1994, 1995
22 * Remy Card (card@masi.ibp.fr)
23 * Laboratoire MASI - Institut Blaise Pascal
24 * Universite Pierre et Marie Curie (Paris VI)
28 * linux/fs/minix/dir.c
30 * Copyright (C) 1991, 1992 Linus Torvalds
32 * ext2 directory handling functions
34 * Big-endian to little-endian byte-swapping/bitmaps by
35 * David S. Miller (davem@caip.rutgers.edu), 1995
37 * All code that works with directory layout had been switched to pagecache
41 #include <linux/pagemap.h>
46 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
47 * more robust, but we have what we have
49 static inline unsigned nilfs_chunk_size(struct inode *inode)
51 return inode->i_sb->s_blocksize;
54 static inline void nilfs_put_page(struct page *page)
61 * Return the offset into page `page_nr' of the last valid
62 * byte in that page, plus one.
64 static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
66 unsigned last_byte = inode->i_size;
68 last_byte -= page_nr << PAGE_SHIFT;
69 if (last_byte > PAGE_SIZE)
70 last_byte = PAGE_SIZE;
74 static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
76 loff_t pos = page_offset(page) + from;
77 return __block_write_begin(page, pos, to - from, nilfs_get_block);
80 static void nilfs_commit_chunk(struct page *page,
81 struct address_space *mapping,
82 unsigned from, unsigned to)
84 struct inode *dir = mapping->host;
85 loff_t pos = page_offset(page) + from;
86 unsigned len = to - from;
87 unsigned nr_dirty, copied;
90 nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
91 copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
92 if (pos + copied > dir->i_size)
93 i_size_write(dir, pos + copied);
95 nilfs_set_transaction_flag(NILFS_TI_SYNC);
96 err = nilfs_set_file_dirty(dir, nr_dirty);
97 WARN_ON(err); /* do not happen */
101 static bool nilfs_check_page(struct page *page)
103 struct inode *dir = page->mapping->host;
104 struct super_block *sb = dir->i_sb;
105 unsigned chunk_size = nilfs_chunk_size(dir);
106 char *kaddr = page_address(page);
107 unsigned offs, rec_len;
108 unsigned limit = PAGE_SIZE;
109 struct nilfs_dir_entry *p;
112 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
113 limit = dir->i_size & ~PAGE_MASK;
114 if (limit & (chunk_size - 1))
119 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
120 p = (struct nilfs_dir_entry *)(kaddr + offs);
121 rec_len = nilfs_rec_len_from_disk(p->rec_len);
123 if (rec_len < NILFS_DIR_REC_LEN(1))
127 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
129 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
135 SetPageChecked(page);
138 /* Too bad, we had an error */
141 nilfs_error(sb, "nilfs_check_page",
142 "size of directory #%lu is not a multiple of chunk size",
147 error = "rec_len is smaller than minimal";
150 error = "unaligned directory entry";
153 error = "rec_len is too small for name_len";
156 error = "directory entry across blocks";
158 nilfs_error(sb, "nilfs_check_page", "bad entry in directory #%lu: %s - "
159 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
160 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
161 (unsigned long) le64_to_cpu(p->inode),
162 rec_len, p->name_len);
165 p = (struct nilfs_dir_entry *)(kaddr + offs);
166 nilfs_error(sb, "nilfs_check_page",
167 "entry in directory #%lu spans the page boundary"
168 "offset=%lu, inode=%lu",
169 dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
170 (unsigned long) le64_to_cpu(p->inode));
176 static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
178 struct address_space *mapping = dir->i_mapping;
179 struct page *page = read_mapping_page(mapping, n, NULL);
183 if (unlikely(!PageChecked(page))) {
184 if (PageError(page) || !nilfs_check_page(page))
191 nilfs_put_page(page);
192 return ERR_PTR(-EIO);
196 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
198 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
201 nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
203 if (len != de->name_len)
207 return !memcmp(name, de->name, len);
211 * p is at least 6 bytes before the end of page
213 static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
215 return (struct nilfs_dir_entry *)((char *)p +
216 nilfs_rec_len_from_disk(p->rec_len));
220 nilfs_filetype_table[NILFS_FT_MAX] = {
221 [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
222 [NILFS_FT_REG_FILE] = DT_REG,
223 [NILFS_FT_DIR] = DT_DIR,
224 [NILFS_FT_CHRDEV] = DT_CHR,
225 [NILFS_FT_BLKDEV] = DT_BLK,
226 [NILFS_FT_FIFO] = DT_FIFO,
227 [NILFS_FT_SOCK] = DT_SOCK,
228 [NILFS_FT_SYMLINK] = DT_LNK,
233 nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
234 [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
235 [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
236 [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
237 [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
238 [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
239 [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
240 [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
243 static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
245 umode_t mode = inode->i_mode;
247 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
250 static int nilfs_readdir(struct file *file, struct dir_context *ctx)
252 loff_t pos = ctx->pos;
253 struct inode *inode = file_inode(file);
254 struct super_block *sb = inode->i_sb;
255 unsigned int offset = pos & ~PAGE_MASK;
256 unsigned long n = pos >> PAGE_SHIFT;
257 unsigned long npages = dir_pages(inode);
258 /* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */
260 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
263 for ( ; n < npages; n++, offset = 0) {
265 struct nilfs_dir_entry *de;
266 struct page *page = nilfs_get_page(inode, n);
269 nilfs_error(sb, __func__, "bad page in #%lu",
271 ctx->pos += PAGE_SIZE - offset;
274 kaddr = page_address(page);
275 de = (struct nilfs_dir_entry *)(kaddr + offset);
276 limit = kaddr + nilfs_last_byte(inode, n) -
277 NILFS_DIR_REC_LEN(1);
278 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
279 if (de->rec_len == 0) {
280 nilfs_error(sb, __func__,
281 "zero-length directory entry");
282 nilfs_put_page(page);
288 if (de->file_type < NILFS_FT_MAX)
289 t = nilfs_filetype_table[de->file_type];
293 if (!dir_emit(ctx, de->name, de->name_len,
294 le64_to_cpu(de->inode), t)) {
295 nilfs_put_page(page);
299 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
301 nilfs_put_page(page);
309 * finds an entry in the specified directory with the wanted name. It
310 * returns the page in which the entry was found, and the entry itself
311 * (as a parameter - res_dir). Page is returned mapped and unlocked.
312 * Entry is guaranteed to be valid.
314 struct nilfs_dir_entry *
315 nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
316 struct page **res_page)
318 const unsigned char *name = qstr->name;
319 int namelen = qstr->len;
320 unsigned reclen = NILFS_DIR_REC_LEN(namelen);
321 unsigned long start, n;
322 unsigned long npages = dir_pages(dir);
323 struct page *page = NULL;
324 struct nilfs_inode_info *ei = NILFS_I(dir);
325 struct nilfs_dir_entry *de;
333 start = ei->i_dir_start_lookup;
339 page = nilfs_get_page(dir, n);
341 kaddr = page_address(page);
342 de = (struct nilfs_dir_entry *)kaddr;
343 kaddr += nilfs_last_byte(dir, n) - reclen;
344 while ((char *) de <= kaddr) {
345 if (de->rec_len == 0) {
346 nilfs_error(dir->i_sb, __func__,
347 "zero-length directory entry");
348 nilfs_put_page(page);
351 if (nilfs_match(namelen, name, de))
353 de = nilfs_next_entry(de);
355 nilfs_put_page(page);
359 /* next page is past the blocks we've got */
360 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
361 nilfs_error(dir->i_sb, __func__,
362 "dir %lu size %lld exceeds block count %llu",
363 dir->i_ino, dir->i_size,
364 (unsigned long long)dir->i_blocks);
367 } while (n != start);
373 ei->i_dir_start_lookup = n;
377 struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
379 struct page *page = nilfs_get_page(dir, 0);
380 struct nilfs_dir_entry *de = NULL;
383 de = nilfs_next_entry(
384 (struct nilfs_dir_entry *)page_address(page));
390 ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
393 struct nilfs_dir_entry *de;
396 de = nilfs_find_entry(dir, qstr, &page);
398 res = le64_to_cpu(de->inode);
405 /* Releases the page */
406 void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
407 struct page *page, struct inode *inode)
409 unsigned from = (char *) de - (char *) page_address(page);
410 unsigned to = from + nilfs_rec_len_from_disk(de->rec_len);
411 struct address_space *mapping = page->mapping;
415 err = nilfs_prepare_chunk(page, from, to);
417 de->inode = cpu_to_le64(inode->i_ino);
418 nilfs_set_de_type(de, inode);
419 nilfs_commit_chunk(page, mapping, from, to);
420 nilfs_put_page(page);
421 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
427 int nilfs_add_link(struct dentry *dentry, struct inode *inode)
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 chunk_size = nilfs_chunk_size(dir);
433 unsigned reclen = NILFS_DIR_REC_LEN(namelen);
434 unsigned short rec_len, name_len;
435 struct page *page = NULL;
436 struct nilfs_dir_entry *de;
437 unsigned long npages = dir_pages(dir);
444 * We take care of directory expansion in the same loop.
445 * This code plays outside i_size, so it locks the page
446 * to protect that region.
448 for (n = 0; n <= npages; n++) {
451 page = nilfs_get_page(dir, n);
456 kaddr = page_address(page);
457 dir_end = kaddr + nilfs_last_byte(dir, n);
458 de = (struct nilfs_dir_entry *)kaddr;
459 kaddr += PAGE_SIZE - reclen;
460 while ((char *)de <= kaddr) {
461 if ((char *)de == dir_end) {
464 rec_len = chunk_size;
465 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
469 if (de->rec_len == 0) {
470 nilfs_error(dir->i_sb, __func__,
471 "zero-length directory entry");
476 if (nilfs_match(namelen, name, de))
478 name_len = NILFS_DIR_REC_LEN(de->name_len);
479 rec_len = nilfs_rec_len_from_disk(de->rec_len);
480 if (!de->inode && rec_len >= reclen)
482 if (rec_len >= name_len + reclen)
484 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
487 nilfs_put_page(page);
493 from = (char *)de - (char *)page_address(page);
495 err = nilfs_prepare_chunk(page, from, to);
499 struct nilfs_dir_entry *de1;
501 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
502 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
503 de->rec_len = nilfs_rec_len_to_disk(name_len);
506 de->name_len = namelen;
507 memcpy(de->name, name, namelen);
508 de->inode = cpu_to_le64(inode->i_ino);
509 nilfs_set_de_type(de, inode);
510 nilfs_commit_chunk(page, page->mapping, from, to);
511 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
512 nilfs_mark_inode_dirty(dir);
515 nilfs_put_page(page);
524 * nilfs_delete_entry deletes a directory entry by merging it with the
525 * previous entry. Page is up-to-date. Releases the page.
527 int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
529 struct address_space *mapping = page->mapping;
530 struct inode *inode = mapping->host;
531 char *kaddr = page_address(page);
532 unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
533 unsigned to = ((char *)dir - kaddr) +
534 nilfs_rec_len_from_disk(dir->rec_len);
535 struct nilfs_dir_entry *pde = NULL;
536 struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from);
539 while ((char *)de < (char *)dir) {
540 if (de->rec_len == 0) {
541 nilfs_error(inode->i_sb, __func__,
542 "zero-length directory entry");
547 de = nilfs_next_entry(de);
550 from = (char *)pde - (char *)page_address(page);
552 err = nilfs_prepare_chunk(page, from, to);
555 pde->rec_len = nilfs_rec_len_to_disk(to - from);
557 nilfs_commit_chunk(page, mapping, from, to);
558 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
560 nilfs_put_page(page);
565 * Set the first fragment of directory.
567 int nilfs_make_empty(struct inode *inode, struct inode *parent)
569 struct address_space *mapping = inode->i_mapping;
570 struct page *page = grab_cache_page(mapping, 0);
571 unsigned chunk_size = nilfs_chunk_size(inode);
572 struct nilfs_dir_entry *de;
579 err = nilfs_prepare_chunk(page, 0, chunk_size);
584 kaddr = kmap_atomic(page);
585 memset(kaddr, 0, chunk_size);
586 de = (struct nilfs_dir_entry *)kaddr;
588 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
589 memcpy(de->name, ".\0\0", 4);
590 de->inode = cpu_to_le64(inode->i_ino);
591 nilfs_set_de_type(de, inode);
593 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
595 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
596 de->inode = cpu_to_le64(parent->i_ino);
597 memcpy(de->name, "..\0", 4);
598 nilfs_set_de_type(de, inode);
599 kunmap_atomic(kaddr);
600 nilfs_commit_chunk(page, mapping, 0, chunk_size);
607 * routine to check that the specified directory is empty (for rmdir)
609 int nilfs_empty_dir(struct inode *inode)
611 struct page *page = NULL;
612 unsigned long i, npages = dir_pages(inode);
614 for (i = 0; i < npages; i++) {
616 struct nilfs_dir_entry *de;
618 page = nilfs_get_page(inode, i);
622 kaddr = page_address(page);
623 de = (struct nilfs_dir_entry *)kaddr;
624 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
626 while ((char *)de <= kaddr) {
627 if (de->rec_len == 0) {
628 nilfs_error(inode->i_sb, __func__,
629 "zero-length directory entry "
630 "(kaddr=%p, de=%p)\n", kaddr, de);
633 if (de->inode != 0) {
634 /* check for . and .. */
635 if (de->name[0] != '.')
637 if (de->name_len > 2)
639 if (de->name_len < 2) {
641 cpu_to_le64(inode->i_ino))
643 } else if (de->name[1] != '.')
646 de = nilfs_next_entry(de);
648 nilfs_put_page(page);
653 nilfs_put_page(page);
657 const struct file_operations nilfs_dir_operations = {
658 .llseek = generic_file_llseek,
659 .read = generic_read_dir,
660 .iterate_shared = nilfs_readdir,
661 .unlocked_ioctl = nilfs_ioctl,
663 .compat_ioctl = nilfs_compat_ioctl,
664 #endif /* CONFIG_COMPAT */
665 .fsync = nilfs_sync_file,