blob: 197a63e9d10215b54e28179b7976e6c0b56b5384 [file] [log] [blame]
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -07001/*
2 * dir.c - NILFS directory entry operations
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
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.
10 *
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.
15 *
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
19 *
20 * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>
21 */
22/*
23 * linux/fs/ext2/dir.c
24 *
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)
29 *
30 * from
31 *
32 * linux/fs/minix/dir.c
33 *
34 * Copyright (C) 1991, 1992 Linus Torvalds
35 *
36 * ext2 directory handling functions
37 *
38 * Big-endian to little-endian byte-swapping/bitmaps by
39 * David S. Miller (davem@caip.rutgers.edu), 1995
40 *
41 * All code that works with directory layout had been switched to pagecache
42 * and moved here. AV
43 */
44
45#include <linux/pagemap.h>
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -070046#include "nilfs.h"
47#include "page.h"
48
49/*
50 * nilfs uses block-sized chunks. Arguably, sector-sized ones would be
51 * more robust, but we have what we have
52 */
53static inline unsigned nilfs_chunk_size(struct inode *inode)
54{
55 return inode->i_sb->s_blocksize;
56}
57
58static inline void nilfs_put_page(struct page *page)
59{
60 kunmap(page);
61 page_cache_release(page);
62}
63
64static inline unsigned long dir_pages(struct inode *inode)
65{
66 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
67}
68
69/*
70 * Return the offset into page `page_nr' of the last valid
71 * byte in that page, plus one.
72 */
73static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
74{
75 unsigned last_byte = inode->i_size;
76
77 last_byte -= page_nr << PAGE_CACHE_SHIFT;
78 if (last_byte > PAGE_CACHE_SIZE)
79 last_byte = PAGE_CACHE_SIZE;
80 return last_byte;
81}
82
Christoph Hellwigf4e420d2010-06-04 11:29:56 +020083static int nilfs_prepare_chunk(struct page *page, unsigned from, unsigned to)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -070084{
85 loff_t pos = page_offset(page) + from;
Christoph Hellwig6e1db882010-06-04 11:29:57 +020086 return __block_write_begin(page, pos, to - from, nilfs_get_block);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -070087}
88
Jiro SEKIBA2093abf2009-11-27 19:41:11 +090089static void nilfs_commit_chunk(struct page *page,
90 struct address_space *mapping,
91 unsigned from, unsigned to)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -070092{
93 struct inode *dir = mapping->host;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -070094 loff_t pos = page_offset(page) + from;
95 unsigned len = to - from;
96 unsigned nr_dirty, copied;
97 int err;
98
99 nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
100 copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
Jiro SEKIBA58d55472009-11-27 19:41:12 +0900101 if (pos + copied > dir->i_size)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700102 i_size_write(dir, pos + copied);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700103 if (IS_DIRSYNC(dir))
104 nilfs_set_transaction_flag(NILFS_TI_SYNC);
Ryusuke Konishibcbc8c62010-12-27 00:05:49 +0900105 err = nilfs_set_file_dirty(dir, nr_dirty);
Jiro SEKIBA2093abf2009-11-27 19:41:11 +0900106 WARN_ON(err); /* do not happen */
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700107 unlock_page(page);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700108}
109
110static void nilfs_check_page(struct page *page)
111{
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;
119 char *error;
120
121 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
122 limit = dir->i_size & ~PAGE_CACHE_MASK;
123 if (limit & (chunk_size - 1))
124 goto Ebadsize;
125 if (!limit)
126 goto out;
127 }
128 for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
129 p = (struct nilfs_dir_entry *)(kaddr + offs);
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900130 rec_len = nilfs_rec_len_from_disk(p->rec_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700131
132 if (rec_len < NILFS_DIR_REC_LEN(1))
133 goto Eshort;
134 if (rec_len & 3)
135 goto Ealign;
136 if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
137 goto Enamelen;
138 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
139 goto Espan;
140 }
141 if (offs != limit)
142 goto Eend;
143out:
144 SetPageChecked(page);
145 return;
146
147 /* Too bad, we had an error */
148
149Ebadsize:
150 nilfs_error(sb, "nilfs_check_page",
151 "size of directory #%lu is not a multiple of chunk size",
152 dir->i_ino
153 );
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";
166bad_entry:
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);
172 goto fail;
173Eend:
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));
180fail:
181 SetPageChecked(page);
182 SetPageError(page);
183}
184
185static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
186{
187 struct address_space *mapping = dir->i_mapping;
Ryusuke Konishic28e69d2010-07-24 17:09:10 +0900188 struct page *page = read_mapping_page(mapping, n, NULL);
189
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700190 if (!IS_ERR(page)) {
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700191 kmap(page);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700192 if (!PageChecked(page))
193 nilfs_check_page(page);
194 if (PageError(page))
195 goto fail;
196 }
197 return page;
198
199fail:
200 nilfs_put_page(page);
201 return ERR_PTR(-EIO);
202}
203
204/*
205 * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
206 *
207 * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
208 */
209static int
Al Viro072f98b2010-01-31 21:03:58 -0500210nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700211{
212 if (len != de->name_len)
213 return 0;
214 if (!de->inode)
215 return 0;
216 return !memcmp(name, de->name, len);
217}
218
219/*
220 * p is at least 6 bytes before the end of page
221 */
222static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
223{
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900224 return (struct nilfs_dir_entry *)((char *)p +
225 nilfs_rec_len_from_disk(p->rec_len));
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700226}
227
228static unsigned char
229nilfs_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,
238};
239
240#define S_SHIFT 12
241static unsigned char
242nilfs_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,
250};
251
252static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
253{
Al Viroc6e49e32011-07-26 03:07:14 -0400254 umode_t mode = inode->i_mode;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700255
256 de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
257}
258
Al Viro1616abe2013-05-16 14:36:14 -0400259static int nilfs_readdir(struct file *file, struct dir_context *ctx)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700260{
Al Viro1616abe2013-05-16 14:36:14 -0400261 loff_t pos = ctx->pos;
262 struct inode *inode = file_inode(file);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700263 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); */
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700268
269 if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
Al Viro1616abe2013-05-16 14:36:14 -0400270 return 0;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700271
272 for ( ; n < npages; n++, offset = 0) {
273 char *kaddr, *limit;
274 struct nilfs_dir_entry *de;
275 struct page *page = nilfs_get_page(inode, n);
276
277 if (IS_ERR(page)) {
278 nilfs_error(sb, __func__, "bad page in #%lu",
279 inode->i_ino);
Al Viro1616abe2013-05-16 14:36:14 -0400280 ctx->pos += PAGE_CACHE_SIZE - offset;
281 return -EIO;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700282 }
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");
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700291 nilfs_put_page(page);
Al Viro1616abe2013-05-16 14:36:14 -0400292 return -EIO;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700293 }
294 if (de->inode) {
Al Viro1616abe2013-05-16 14:36:14 -0400295 unsigned char t;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700296
Al Viro1616abe2013-05-16 14:36:14 -0400297 if (de->file_type < NILFS_FT_MAX)
298 t = nilfs_filetype_table[de->file_type];
299 else
300 t = DT_UNKNOWN;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700301
Al Viro1616abe2013-05-16 14:36:14 -0400302 if (!dir_emit(ctx, de->name, de->name_len,
303 le64_to_cpu(de->inode), t)) {
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700304 nilfs_put_page(page);
Al Viro1616abe2013-05-16 14:36:14 -0400305 return 0;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700306 }
307 }
Al Viro1616abe2013-05-16 14:36:14 -0400308 ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700309 }
310 nilfs_put_page(page);
311 }
Al Viro1616abe2013-05-16 14:36:14 -0400312 return 0;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700313}
314
315/*
316 * nilfs_find_entry()
317 *
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.
322 */
323struct nilfs_dir_entry *
Al Viro03190032010-01-31 21:02:09 -0500324nilfs_find_entry(struct inode *dir, const struct qstr *qstr,
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700325 struct page **res_page)
326{
Al Viro03190032010-01-31 21:02:09 -0500327 const unsigned char *name = qstr->name;
328 int namelen = qstr->len;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700329 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;
335
336 if (npages == 0)
337 goto out;
338
339 /* OFFSET_CACHE */
340 *res_page = NULL;
341
342 start = ei->i_dir_start_lookup;
343 if (start >= npages)
344 start = 0;
345 n = start;
346 do {
347 char *kaddr;
348 page = nilfs_get_page(dir, n);
349 if (!IS_ERR(page)) {
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);
358 goto out;
359 }
360 if (nilfs_match(namelen, name, de))
361 goto found;
362 de = nilfs_next_entry(de);
363 }
364 nilfs_put_page(page);
365 }
366 if (++n >= npages)
367 n = 0;
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__,
Ryusuke Konishi16215622010-03-14 03:17:45 +0900371 "dir %lu size %lld exceeds block count %llu",
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700372 dir->i_ino, dir->i_size,
373 (unsigned long long)dir->i_blocks);
374 goto out;
375 }
376 } while (n != start);
377out:
378 return NULL;
379
380found:
381 *res_page = page;
382 ei->i_dir_start_lookup = n;
383 return de;
384}
385
386struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
387{
388 struct page *page = nilfs_get_page(dir, 0);
389 struct nilfs_dir_entry *de = NULL;
390
391 if (!IS_ERR(page)) {
392 de = nilfs_next_entry(
393 (struct nilfs_dir_entry *)page_address(page));
394 *p = page;
395 }
396 return de;
397}
398
Al Viro03190032010-01-31 21:02:09 -0500399ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700400{
401 ino_t res = 0;
402 struct nilfs_dir_entry *de;
403 struct page *page;
404
Al Viro03190032010-01-31 21:02:09 -0500405 de = nilfs_find_entry(dir, qstr, &page);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700406 if (de) {
407 res = le64_to_cpu(de->inode);
408 kunmap(page);
409 page_cache_release(page);
410 }
411 return res;
412}
413
414/* Releases the page */
415void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
416 struct page *page, struct inode *inode)
417{
418 unsigned from = (char *) de - (char *) page_address(page);
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900419 unsigned to = from + nilfs_rec_len_from_disk(de->rec_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700420 struct address_space *mapping = page->mapping;
421 int err;
422
423 lock_page(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200424 err = nilfs_prepare_chunk(page, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700425 BUG_ON(err);
426 de->inode = cpu_to_le64(inode->i_ino);
427 nilfs_set_de_type(de, inode);
Jiro SEKIBA2093abf2009-11-27 19:41:11 +0900428 nilfs_commit_chunk(page, mapping, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700429 nilfs_put_page(page);
430 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700431}
432
433/*
434 * Parent is locked.
435 */
436int nilfs_add_link(struct dentry *dentry, struct inode *inode)
437{
438 struct inode *dir = dentry->d_parent->d_inode;
Al Viro072f98b2010-01-31 21:03:58 -0500439 const unsigned char *name = dentry->d_name.name;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700440 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);
447 unsigned long n;
448 char *kaddr;
449 unsigned from, to;
450 int err;
451
452 /*
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.
456 */
457 for (n = 0; n <= npages; n++) {
458 char *dir_end;
459
460 page = nilfs_get_page(dir, n);
461 err = PTR_ERR(page);
462 if (IS_ERR(page))
463 goto out;
464 lock_page(page);
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) {
471 /* We hit i_size */
472 name_len = 0;
473 rec_len = chunk_size;
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900474 de->rec_len = nilfs_rec_len_to_disk(chunk_size);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700475 de->inode = 0;
476 goto got_it;
477 }
478 if (de->rec_len == 0) {
479 nilfs_error(dir->i_sb, __func__,
480 "zero-length directory entry");
481 err = -EIO;
482 goto out_unlock;
483 }
484 err = -EEXIST;
485 if (nilfs_match(namelen, name, de))
486 goto out_unlock;
487 name_len = NILFS_DIR_REC_LEN(de->name_len);
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900488 rec_len = nilfs_rec_len_from_disk(de->rec_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700489 if (!de->inode && rec_len >= reclen)
490 goto got_it;
491 if (rec_len >= name_len + reclen)
492 goto got_it;
493 de = (struct nilfs_dir_entry *)((char *)de + rec_len);
494 }
495 unlock_page(page);
496 nilfs_put_page(page);
497 }
498 BUG();
499 return -EINVAL;
500
501got_it:
502 from = (char *)de - (char *)page_address(page);
503 to = from + rec_len;
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200504 err = nilfs_prepare_chunk(page, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700505 if (err)
506 goto out_unlock;
507 if (de->inode) {
508 struct nilfs_dir_entry *de1;
509
510 de1 = (struct nilfs_dir_entry *)((char *)de + name_len);
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900511 de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len);
512 de->rec_len = nilfs_rec_len_to_disk(name_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700513 de = de1;
514 }
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);
Jiro SEKIBA2093abf2009-11-27 19:41:11 +0900519 nilfs_commit_chunk(page, page->mapping, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700520 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
Jiro SEKIBAabdb3182009-11-27 19:41:14 +0900521 nilfs_mark_inode_dirty(dir);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700522 /* OFFSET_CACHE */
523out_put:
524 nilfs_put_page(page);
525out:
526 return err;
527out_unlock:
528 unlock_page(page);
529 goto out_put;
530}
531
532/*
533 * nilfs_delete_entry deletes a directory entry by merging it with the
534 * previous entry. Page is up-to-date. Releases the page.
535 */
536int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page)
537{
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);
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900542 unsigned to = ((char *)dir - kaddr) +
543 nilfs_rec_len_from_disk(dir->rec_len);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700544 struct nilfs_dir_entry *pde = NULL;
545 struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from);
546 int err;
547
548 while ((char *)de < (char *)dir) {
549 if (de->rec_len == 0) {
550 nilfs_error(inode->i_sb, __func__,
551 "zero-length directory entry");
552 err = -EIO;
553 goto out;
554 }
555 pde = de;
556 de = nilfs_next_entry(de);
557 }
558 if (pde)
559 from = (char *)pde - (char *)page_address(page);
560 lock_page(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200561 err = nilfs_prepare_chunk(page, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700562 BUG_ON(err);
563 if (pde)
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900564 pde->rec_len = nilfs_rec_len_to_disk(to - from);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700565 dir->inode = 0;
Jiro SEKIBA2093abf2009-11-27 19:41:11 +0900566 nilfs_commit_chunk(page, mapping, from, to);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700567 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700568out:
569 nilfs_put_page(page);
570 return err;
571}
572
573/*
574 * Set the first fragment of directory.
575 */
576int nilfs_make_empty(struct inode *inode, struct inode *parent)
577{
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;
582 int err;
583 void *kaddr;
584
585 if (!page)
586 return -ENOMEM;
587
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200588 err = nilfs_prepare_chunk(page, 0, chunk_size);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700589 if (unlikely(err)) {
590 unlock_page(page);
591 goto fail;
592 }
Cong Wang7b9c0972011-11-25 23:14:33 +0800593 kaddr = kmap_atomic(page);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700594 memset(kaddr, 0, chunk_size);
595 de = (struct nilfs_dir_entry *)kaddr;
596 de->name_len = 1;
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900597 de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1));
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700598 memcpy(de->name, ".\0\0", 4);
599 de->inode = cpu_to_le64(inode->i_ino);
600 nilfs_set_de_type(de, inode);
601
602 de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1));
603 de->name_len = 2;
Ryusuke Konishi6cda9fa2010-07-25 20:39:03 +0900604 de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1));
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700605 de->inode = cpu_to_le64(parent->i_ino);
606 memcpy(de->name, "..\0", 4);
607 nilfs_set_de_type(de, inode);
Cong Wang7b9c0972011-11-25 23:14:33 +0800608 kunmap_atomic(kaddr);
Jiro SEKIBA2093abf2009-11-27 19:41:11 +0900609 nilfs_commit_chunk(page, mapping, 0, chunk_size);
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700610fail:
611 page_cache_release(page);
612 return err;
613}
614
615/*
616 * routine to check that the specified directory is empty (for rmdir)
617 */
618int nilfs_empty_dir(struct inode *inode)
619{
620 struct page *page = NULL;
621 unsigned long i, npages = dir_pages(inode);
622
623 for (i = 0; i < npages; i++) {
624 char *kaddr;
625 struct nilfs_dir_entry *de;
626
627 page = nilfs_get_page(inode, i);
628 if (IS_ERR(page))
629 continue;
630
631 kaddr = page_address(page);
632 de = (struct nilfs_dir_entry *)kaddr;
633 kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
634
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);
640 goto not_empty;
641 }
642 if (de->inode != 0) {
643 /* check for . and .. */
644 if (de->name[0] != '.')
645 goto not_empty;
646 if (de->name_len > 2)
647 goto not_empty;
648 if (de->name_len < 2) {
649 if (de->inode !=
650 cpu_to_le64(inode->i_ino))
651 goto not_empty;
652 } else if (de->name[1] != '.')
653 goto not_empty;
654 }
655 de = nilfs_next_entry(de);
656 }
657 nilfs_put_page(page);
658 }
659 return 1;
660
661not_empty:
662 nilfs_put_page(page);
663 return 0;
664}
665
Alexey Dobriyan828c0952009-10-01 15:43:56 -0700666const struct file_operations nilfs_dir_operations = {
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700667 .llseek = generic_file_llseek,
668 .read = generic_read_dir,
Al Viro1616abe2013-05-16 14:36:14 -0400669 .iterate = nilfs_readdir,
Ryusuke Konishi7a946192009-04-06 19:01:53 -0700670 .unlocked_ioctl = nilfs_ioctl,
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700671#ifdef CONFIG_COMPAT
Ryusuke Konishi828b1c52011-02-03 21:26:17 +0900672 .compat_ioctl = nilfs_compat_ioctl,
Yoshiji Amagai2ba466d2009-04-06 19:01:34 -0700673#endif /* CONFIG_COMPAT */
674 .fsync = nilfs_sync_file,
675
676};