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.
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;
78 return __block_write_begin(page, pos, to - from, nilfs_get_block);
81 static void nilfs_commit_chunk(struct page *page,
82 struct address_space *mapping,
83 unsigned from, unsigned to)
85 struct inode *dir = mapping->host;
86 loff_t pos = page_offset(page) + from;
87 unsigned len = to - from;
88 unsigned nr_dirty, copied;
91 nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
92 copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
93 if (pos + copied > dir->i_size)
94 i_size_write(dir, pos + copied);
96 nilfs_set_transaction_flag(NILFS_TI_SYNC);
97 err = nilfs_set_file_dirty(dir, nr_dirty);
98 WARN_ON(err); /* do not happen */
102 static bool nilfs_check_page(struct page *page)
104 struct inode *dir = page->mapping->host;
105 struct super_block *sb = dir->i_sb;
106 unsigned chunk_size = nilfs_chunk_size(dir);
107 char *kaddr = page_address(page);
108 unsigned offs, rec_len;
109 unsigned limit = PAGE_SIZE;
110 struct nilfs_dir_entry *p;
113 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
114 limit = dir->i_size & ~PAGE_MASK;
115 if (limit & (chunk_size - 1))
120 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
121 p = (struct nilfs_dir_entry *)(kaddr + offs);
122 rec_len = nilfs_rec_len_from_disk(p->rec_len);
124 if (rec_len < NILFS_DIR_REC_LEN(1))
128 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
130 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
136 SetPageChecked(page);
139 /* Too bad, we had an error */
142 nilfs_error(sb, "nilfs_check_page",
143 "size of directory #%lu is not a multiple of chunk size",
148 error = "rec_len is smaller than minimal";
151 error = "unaligned directory entry";
154 error = "rec_len is too small for name_len";
157 error = "directory entry across blocks";
159 nilfs_error(sb, "nilfs_check_page", "bad entry in directory #%lu: %s - "
160 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
161 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
162 (unsigned long) le64_to_cpu(p->inode),
163 rec_len, p->name_len);
166 p = (struct nilfs_dir_entry *)(kaddr + offs);
167 nilfs_error(sb, "nilfs_check_page",
168 "entry in directory #%lu spans the page boundary"
169 "offset=%lu, inode=%lu",
170 dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
171 (unsigned long) le64_to_cpu(p->inode));
177 static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
179 struct address_space *mapping = dir->i_mapping;
180 struct page *page = read_mapping_page(mapping, n, NULL);
184 if (unlikely(!PageChecked(page))) {
185 if (PageError(page) || !nilfs_check_page(page))
192 nilfs_put_page(page);
193 return ERR_PTR(-EIO);
197 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
199 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
202 nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
204 if (len != de->name_len)
208 return !memcmp(name, de->name, len);
212 * p is at least 6 bytes before the end of page
214 static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
216 return (struct nilfs_dir_entry *)((char *)p +
217 nilfs_rec_len_from_disk(p->rec_len));
221 nilfs_filetype_table[NILFS_FT_MAX] = {
222 [NILFS_FT_UNKNOWN] = DT_UNKNOWN,
223 [NILFS_FT_REG_FILE] = DT_REG,
224 [NILFS_FT_DIR] = DT_DIR,
225 [NILFS_FT_CHRDEV] = DT_CHR,
226 [NILFS_FT_BLKDEV] = DT_BLK,
227 [NILFS_FT_FIFO] = DT_FIFO,
228 [NILFS_FT_SOCK] = DT_SOCK,
229 [NILFS_FT_SYMLINK] = DT_LNK,
234 nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
235 [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
236 [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
237 [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
238 [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
239 [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
240 [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
241 [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
244 static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
246 umode_t mode = inode->i_mode;
248 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
251 static int nilfs_readdir(struct file *file, struct dir_context *ctx)
253 loff_t pos = ctx->pos;
254 struct inode *inode = file_inode(file);
255 struct super_block *sb = inode->i_sb;
256 unsigned int offset = pos & ~PAGE_MASK;
257 unsigned long n = pos >> PAGE_SHIFT;
258 unsigned long npages = dir_pages(inode);
259 /* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */
261 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
264 for ( ; n < npages; n++, offset = 0) {
266 struct nilfs_dir_entry *de;
267 struct page *page = nilfs_get_page(inode, n);
270 nilfs_error(sb, __func__, "bad page in #%lu",
272 ctx->pos += PAGE_SIZE - offset;
275 kaddr = page_address(page);
276 de = (struct nilfs_dir_entry *)(kaddr + offset);
277 limit = kaddr + nilfs_last_byte(inode, n) -
278 NILFS_DIR_REC_LEN(1);
279 for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
280 if (de->rec_len == 0) {
281 nilfs_error(sb, __func__,
282 "zero-length directory entry");
283 nilfs_put_page(page);
289 if (de->file_type < NILFS_FT_MAX)
290 t = nilfs_filetype_table[de->file_type];
294 if (!dir_emit(ctx, de->name, de->name_len,
295 le64_to_cpu(de->inode), t)) {
296 nilfs_put_page(page);
300 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
302 nilfs_put_page(page);
310 * finds an entry in the specified directory with the wanted name. It
311 * returns the page in which the entry was found, and the entry itself
312 * (as a parameter - res_dir). Page is returned mapped and unlocked.
313 * Entry is guaranteed to be valid.
315 struct nilfs_dir_entry *
316 nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
317 struct page **res_page)
319 const unsigned char *name = qstr->name;
320 int namelen = qstr->len;
321 unsigned reclen = NILFS_DIR_REC_LEN(namelen);
322 unsigned long start, n;
323 unsigned long npages = dir_pages(dir);
324 struct page *page = NULL;
325 struct nilfs_inode_info *ei = NILFS_I(dir);
326 struct nilfs_dir_entry *de;
334 start = ei->i_dir_start_lookup;
341 page = nilfs_get_page(dir, n);
343 kaddr = page_address(page);
344 de = (struct nilfs_dir_entry *)kaddr;
345 kaddr += nilfs_last_byte(dir, n) - reclen;
346 while ((char *) de <= kaddr) {
347 if (de->rec_len == 0) {
348 nilfs_error(dir->i_sb, __func__,
349 "zero-length directory entry");
350 nilfs_put_page(page);
353 if (nilfs_match(namelen, name, de))
355 de = nilfs_next_entry(de);
357 nilfs_put_page(page);
361 /* next page is past the blocks we've got */
362 if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
363 nilfs_error(dir->i_sb, __func__,
364 "dir %lu size %lld exceeds block count %llu",
365 dir->i_ino, dir->i_size,
366 (unsigned long long)dir->i_blocks);
369 } while (n != start);
375 ei->i_dir_start_lookup = n;
379 struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
381 struct page *page = nilfs_get_page(dir, 0);
382 struct nilfs_dir_entry *de = NULL;
385 de = nilfs_next_entry(
386 (struct nilfs_dir_entry *)page_address(page));
392 ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
395 struct nilfs_dir_entry *de;
398 de = nilfs_find_entry(dir, qstr, &page);
400 res = le64_to_cpu(de->inode);
407 /* Releases the page */
408 void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
409 struct page *page, struct inode *inode)
411 unsigned from = (char *) de - (char *) page_address(page);
412 unsigned to = from + nilfs_rec_len_from_disk(de->rec_len);
413 struct address_space *mapping = page->mapping;
417 err = nilfs_prepare_chunk(page, from, to);
419 de->inode = cpu_to_le64(inode->i_ino);
420 nilfs_set_de_type(de, inode);
421 nilfs_commit_chunk(page, mapping, from, to);
422 nilfs_put_page(page);
423 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
429 int nilfs_add_link(struct dentry *dentry, struct inode *inode)
431 struct inode *dir = d_inode(dentry->d_parent);
432 const unsigned char *name = dentry->d_name.name;
433 int namelen = dentry->d_name.len;
434 unsigned chunk_size = nilfs_chunk_size(dir);
435 unsigned reclen = NILFS_DIR_REC_LEN(namelen);
436 unsigned short rec_len, name_len;
437 struct page *page = NULL;
438 struct nilfs_dir_entry *de;
439 unsigned long npages = dir_pages(dir);
446 * We take care of directory expansion in the same loop.
447 * This code plays outside i_size, so it locks the page
448 * to protect that region.
450 for (n = 0; n <= npages; n++) {
453 page = nilfs_get_page(dir, n);
458 kaddr = page_address(page);
459 dir_end = kaddr + nilfs_last_byte(dir, n);
460 de = (struct nilfs_dir_entry *)kaddr;
461 kaddr += PAGE_SIZE - reclen;
462 while ((char *)de <= kaddr) {
463 if ((char *)de == dir_end) {
466 rec_len = chunk_size;
467 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
471 if (de->rec_len == 0) {
472 nilfs_error(dir->i_sb, __func__,
473 "zero-length directory entry");
478 if (nilfs_match(namelen, name, de))
480 name_len = NILFS_DIR_REC_LEN(de->name_len);
481 rec_len = nilfs_rec_len_from_disk(de->rec_len);
482 if (!de->inode && rec_len >= reclen)
484 if (rec_len >= name_len + reclen)
486 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
489 nilfs_put_page(page);
495 from = (char *)de - (char *)page_address(page);
497 err = nilfs_prepare_chunk(page, from, to);
501 struct nilfs_dir_entry *de1;
503 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
504 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
505 de->rec_len = nilfs_rec_len_to_disk(name_len);
508 de->name_len = namelen;
509 memcpy(de->name, name, namelen);
510 de->inode = cpu_to_le64(inode->i_ino);
511 nilfs_set_de_type(de, inode);
512 nilfs_commit_chunk(page, page->mapping, from, to);
513 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
514 nilfs_mark_inode_dirty(dir);
517 nilfs_put_page(page);
526 * nilfs_delete_entry deletes a directory entry by merging it with the
527 * previous entry. Page is up-to-date. Releases the page.
529 int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
531 struct address_space *mapping = page->mapping;
532 struct inode *inode = mapping->host;
533 char *kaddr = page_address(page);
534 unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
535 unsigned to = ((char *)dir - kaddr) +
536 nilfs_rec_len_from_disk(dir->rec_len);
537 struct nilfs_dir_entry *pde = NULL;
538 struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from);
541 while ((char *)de < (char *)dir) {
542 if (de->rec_len == 0) {
543 nilfs_error(inode->i_sb, __func__,
544 "zero-length directory entry");
549 de = nilfs_next_entry(de);
552 from = (char *)pde - (char *)page_address(page);
554 err = nilfs_prepare_chunk(page, from, to);
557 pde->rec_len = nilfs_rec_len_to_disk(to - from);
559 nilfs_commit_chunk(page, mapping, from, to);
560 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
562 nilfs_put_page(page);
567 * Set the first fragment of directory.
569 int nilfs_make_empty(struct inode *inode, struct inode *parent)
571 struct address_space *mapping = inode->i_mapping;
572 struct page *page = grab_cache_page(mapping, 0);
573 unsigned chunk_size = nilfs_chunk_size(inode);
574 struct nilfs_dir_entry *de;
581 err = nilfs_prepare_chunk(page, 0, chunk_size);
586 kaddr = kmap_atomic(page);
587 memset(kaddr, 0, chunk_size);
588 de = (struct nilfs_dir_entry *)kaddr;
590 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
591 memcpy(de->name, ".\0\0", 4);
592 de->inode = cpu_to_le64(inode->i_ino);
593 nilfs_set_de_type(de, inode);
595 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
597 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
598 de->inode = cpu_to_le64(parent->i_ino);
599 memcpy(de->name, "..\0", 4);
600 nilfs_set_de_type(de, inode);
601 kunmap_atomic(kaddr);
602 nilfs_commit_chunk(page, mapping, 0, chunk_size);
609 * routine to check that the specified directory is empty (for rmdir)
611 int nilfs_empty_dir(struct inode *inode)
613 struct page *page = NULL;
614 unsigned long i, npages = dir_pages(inode);
616 for (i = 0; i < npages; i++) {
618 struct nilfs_dir_entry *de;
620 page = nilfs_get_page(inode, i);
624 kaddr = page_address(page);
625 de = (struct nilfs_dir_entry *)kaddr;
626 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
628 while ((char *)de <= kaddr) {
629 if (de->rec_len == 0) {
630 nilfs_error(inode->i_sb, __func__,
631 "zero-length directory entry "
632 "(kaddr=%p, de=%p)\n", kaddr, de);
635 if (de->inode != 0) {
636 /* check for . and .. */
637 if (de->name[0] != '.')
639 if (de->name_len > 2)
641 if (de->name_len < 2) {
643 cpu_to_le64(inode->i_ino))
645 } else if (de->name[1] != '.')
648 de = nilfs_next_entry(de);
650 nilfs_put_page(page);
655 nilfs_put_page(page);
659 const struct file_operations nilfs_dir_operations = {
660 .llseek = generic_file_llseek,
661 .read = generic_read_dir,
662 .iterate_shared = nilfs_readdir,
663 .unlocked_ioctl = nilfs_ioctl,
665 .compat_ioctl = nilfs_compat_ioctl,
666 #endif /* CONFIG_COMPAT */
667 .fsync = nilfs_sync_file,