blob: 796b491e69785e4b703b7c3a0cbc7e97d3510a40 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/ext2/dir.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext2 directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 *
20 * All code that works with directory layout had been switched to pagecache
21 * and moved here. AV
22 */
23
24#include "ext2.h"
Nick Pigginf34fb6e2007-10-16 01:25:04 -070025#include <linux/buffer_head.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/pagemap.h>
Nick Pigginf34fb6e2007-10-16 01:25:04 -070027#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29typedef struct ext2_dir_entry_2 ext2_dirent;
30
Eric Sandeen40a063f2010-12-07 11:51:05 -060031/*
32 * Tests against MAX_REC_LEN etc were put in place for 64k block
33 * sizes; if that is not possible on this arch, we can skip
34 * those tests and speed things up.
35 */
Jan Kara89910cc2007-10-21 16:41:40 -070036static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
37{
38 unsigned len = le16_to_cpu(dlen);
39
Eric Sandeen40a063f2010-12-07 11:51:05 -060040#if (PAGE_CACHE_SIZE >= 65536)
Jan Kara89910cc2007-10-21 16:41:40 -070041 if (len == EXT2_MAX_REC_LEN)
42 return 1 << 16;
Eric Sandeen40a063f2010-12-07 11:51:05 -060043#endif
Jan Kara89910cc2007-10-21 16:41:40 -070044 return len;
45}
46
47static inline __le16 ext2_rec_len_to_disk(unsigned len)
48{
Eric Sandeen40a063f2010-12-07 11:51:05 -060049#if (PAGE_CACHE_SIZE >= 65536)
Jan Kara89910cc2007-10-21 16:41:40 -070050 if (len == (1 << 16))
51 return cpu_to_le16(EXT2_MAX_REC_LEN);
Julia Lawall2c116192008-04-28 02:16:02 -070052 else
53 BUG_ON(len > (1 << 16));
Eric Sandeen40a063f2010-12-07 11:51:05 -060054#endif
Jan Kara89910cc2007-10-21 16:41:40 -070055 return cpu_to_le16(len);
56}
57
Linus Torvalds1da177e2005-04-16 15:20:36 -070058/*
59 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
60 * more robust, but we have what we have
61 */
62static inline unsigned ext2_chunk_size(struct inode *inode)
63{
64 return inode->i_sb->s_blocksize;
65}
66
67static inline void ext2_put_page(struct page *page)
68{
69 kunmap(page);
70 page_cache_release(page);
71}
72
73static inline unsigned long dir_pages(struct inode *inode)
74{
75 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
76}
77
78/*
79 * Return the offset into page `page_nr' of the last valid
80 * byte in that page, plus one.
81 */
82static unsigned
83ext2_last_byte(struct inode *inode, unsigned long page_nr)
84{
85 unsigned last_byte = inode->i_size;
86
87 last_byte -= page_nr << PAGE_CACHE_SHIFT;
88 if (last_byte > PAGE_CACHE_SIZE)
89 last_byte = PAGE_CACHE_SIZE;
90 return last_byte;
91}
92
Nick Pigginf34fb6e2007-10-16 01:25:04 -070093static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070094{
Nick Pigginf34fb6e2007-10-16 01:25:04 -070095 struct address_space *mapping = page->mapping;
96 struct inode *dir = mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 int err = 0;
Nick Pigginf34fb6e2007-10-16 01:25:04 -070098
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 dir->i_version++;
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700100 block_write_end(NULL, mapping, pos, len, len, page, NULL);
101
102 if (pos+len > dir->i_size) {
103 i_size_write(dir, pos+len);
104 mark_inode_dirty(dir);
105 }
106
Jan Kara6b7021e2009-01-15 13:51:29 -0800107 if (IS_DIRSYNC(dir)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 err = write_one_page(page, 1);
Jan Kara6b7021e2009-01-15 13:51:29 -0800109 if (!err)
Christoph Hellwigc37650162010-10-06 10:48:20 +0200110 err = sync_inode_metadata(dir, 1);
Jan Kara6b7021e2009-01-15 13:51:29 -0800111 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 unlock_page(page);
Jan Kara6b7021e2009-01-15 13:51:29 -0800113 }
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700114
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 return err;
116}
117
Eric Sandeenbd395972008-10-15 22:04:02 -0700118static void ext2_check_page(struct page *page, int quiet)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
120 struct inode *dir = page->mapping->host;
121 struct super_block *sb = dir->i_sb;
122 unsigned chunk_size = ext2_chunk_size(dir);
123 char *kaddr = page_address(page);
124 u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
125 unsigned offs, rec_len;
126 unsigned limit = PAGE_CACHE_SIZE;
127 ext2_dirent *p;
128 char *error;
129
130 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
131 limit = dir->i_size & ~PAGE_CACHE_MASK;
132 if (limit & (chunk_size - 1))
133 goto Ebadsize;
134 if (!limit)
135 goto out;
136 }
137 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
138 p = (ext2_dirent *)(kaddr + offs);
Jan Kara89910cc2007-10-21 16:41:40 -0700139 rec_len = ext2_rec_len_from_disk(p->rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
Eric Sandeen40a063f2010-12-07 11:51:05 -0600141 if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 goto Eshort;
Eric Sandeen40a063f2010-12-07 11:51:05 -0600143 if (unlikely(rec_len & 3))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 goto Ealign;
Eric Sandeen40a063f2010-12-07 11:51:05 -0600145 if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 goto Enamelen;
Eric Sandeen40a063f2010-12-07 11:51:05 -0600147 if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 goto Espan;
Eric Sandeen40a063f2010-12-07 11:51:05 -0600149 if (unlikely(le32_to_cpu(p->inode) > max_inumber))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 goto Einumber;
151 }
152 if (offs != limit)
153 goto Eend;
154out:
155 SetPageChecked(page);
156 return;
157
158 /* Too bad, we had an error */
159
160Ebadsize:
Eric Sandeenbd395972008-10-15 22:04:02 -0700161 if (!quiet)
162 ext2_error(sb, __func__,
163 "size of directory #%lu is not a multiple "
164 "of chunk size", dir->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 goto fail;
166Eshort:
167 error = "rec_len is smaller than minimal";
168 goto bad_entry;
169Ealign:
170 error = "unaligned directory entry";
171 goto bad_entry;
172Enamelen:
173 error = "rec_len is too small for name_len";
174 goto bad_entry;
175Espan:
176 error = "directory entry across blocks";
177 goto bad_entry;
178Einumber:
179 error = "inode out of bounds";
180bad_entry:
Eric Sandeenbd395972008-10-15 22:04:02 -0700181 if (!quiet)
182 ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
183 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
184 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
185 (unsigned long) le32_to_cpu(p->inode),
186 rec_len, p->name_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 goto fail;
188Eend:
Eric Sandeenbd395972008-10-15 22:04:02 -0700189 if (!quiet) {
190 p = (ext2_dirent *)(kaddr + offs);
191 ext2_error(sb, "ext2_check_page",
192 "entry in directory #%lu spans the page boundary"
193 "offset=%lu, inode=%lu",
194 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
195 (unsigned long) le32_to_cpu(p->inode));
196 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197fail:
198 SetPageChecked(page);
199 SetPageError(page);
200}
201
Eric Sandeenbd395972008-10-15 22:04:02 -0700202static struct page * ext2_get_page(struct inode *dir, unsigned long n,
203 int quiet)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
205 struct address_space *mapping = dir->i_mapping;
Pekka Enberg090d2b12006-06-23 02:05:08 -0700206 struct page *page = read_mapping_page(mapping, n, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (!IS_ERR(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 kmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 if (!PageChecked(page))
Eric Sandeenbd395972008-10-15 22:04:02 -0700210 ext2_check_page(page, quiet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if (PageError(page))
212 goto fail;
213 }
214 return page;
215
216fail:
217 ext2_put_page(page);
218 return ERR_PTR(-EIO);
219}
220
221/*
222 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
223 *
224 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
225 */
226static inline int ext2_match (int len, const char * const name,
227 struct ext2_dir_entry_2 * de)
228{
229 if (len != de->name_len)
230 return 0;
231 if (!de->inode)
232 return 0;
233 return !memcmp(name, de->name, len);
234}
235
236/*
237 * p is at least 6 bytes before the end of page
238 */
239static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
240{
Jan Kara89910cc2007-10-21 16:41:40 -0700241 return (ext2_dirent *)((char *)p +
242 ext2_rec_len_from_disk(p->rec_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243}
244
245static inline unsigned
246ext2_validate_entry(char *base, unsigned offset, unsigned mask)
247{
248 ext2_dirent *de = (ext2_dirent*)(base + offset);
249 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
250 while ((char*)p < (char*)de) {
251 if (p->rec_len == 0)
252 break;
253 p = ext2_next_entry(p);
254 }
255 return (char *)p - base;
256}
257
258static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
259 [EXT2_FT_UNKNOWN] = DT_UNKNOWN,
260 [EXT2_FT_REG_FILE] = DT_REG,
261 [EXT2_FT_DIR] = DT_DIR,
262 [EXT2_FT_CHRDEV] = DT_CHR,
263 [EXT2_FT_BLKDEV] = DT_BLK,
264 [EXT2_FT_FIFO] = DT_FIFO,
265 [EXT2_FT_SOCK] = DT_SOCK,
266 [EXT2_FT_SYMLINK] = DT_LNK,
267};
268
269#define S_SHIFT 12
270static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
271 [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE,
272 [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR,
273 [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV,
274 [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV,
275 [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO,
276 [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK,
277 [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK,
278};
279
280static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
281{
Al Viro3ea40bc2011-07-26 02:46:18 -0400282 umode_t mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
284 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
285 else
286 de->file_type = 0;
287}
288
289static int
Al Viro80886292013-05-15 18:51:49 -0400290ext2_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
Al Viro80886292013-05-15 18:51:49 -0400292 loff_t pos = ctx->pos;
293 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 struct super_block *sb = inode->i_sb;
295 unsigned int offset = pos & ~PAGE_CACHE_MASK;
296 unsigned long n = pos >> PAGE_CACHE_SHIFT;
297 unsigned long npages = dir_pages(inode);
298 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
299 unsigned char *types = NULL;
Al Viro80886292013-05-15 18:51:49 -0400300 int need_revalidate = file->f_version != inode->i_version;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
302 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
Al Viro2d7f2ea2006-03-15 21:41:59 +0000303 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
305 if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
306 types = ext2_filetype_table;
307
308 for ( ; n < npages; n++, offset = 0) {
309 char *kaddr, *limit;
310 ext2_dirent *de;
Eric Sandeenbd395972008-10-15 22:04:02 -0700311 struct page *page = ext2_get_page(inode, n, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
313 if (IS_ERR(page)) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700314 ext2_error(sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 "bad page in #%lu",
316 inode->i_ino);
Al Viro80886292013-05-15 18:51:49 -0400317 ctx->pos += PAGE_CACHE_SIZE - offset;
Akinobu Mitabbff2862008-04-28 02:16:00 -0700318 return PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 }
320 kaddr = page_address(page);
Al Viro2d7f2ea2006-03-15 21:41:59 +0000321 if (unlikely(need_revalidate)) {
322 if (offset) {
323 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
Al Viro80886292013-05-15 18:51:49 -0400324 ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
Al Viro2d7f2ea2006-03-15 21:41:59 +0000325 }
Al Viro80886292013-05-15 18:51:49 -0400326 file->f_version = inode->i_version;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 need_revalidate = 0;
328 }
329 de = (ext2_dirent *)(kaddr+offset);
330 limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
331 for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
332 if (de->rec_len == 0) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700333 ext2_error(sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 "zero-length directory entry");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 ext2_put_page(page);
Al Viro2d7f2ea2006-03-15 21:41:59 +0000336 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 }
338 if (de->inode) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 unsigned char d_type = DT_UNKNOWN;
340
341 if (types && de->file_type < EXT2_FT_MAX)
342 d_type = types[de->file_type];
343
Al Viro80886292013-05-15 18:51:49 -0400344 if (!dir_emit(ctx, de->name, de->name_len,
345 le32_to_cpu(de->inode),
346 d_type)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 ext2_put_page(page);
Al Viro2d7f2ea2006-03-15 21:41:59 +0000348 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
350 }
Al Viro80886292013-05-15 18:51:49 -0400351 ctx->pos += ext2_rec_len_from_disk(de->rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 }
353 ext2_put_page(page);
354 }
Al Viro2d7f2ea2006-03-15 21:41:59 +0000355 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356}
357
358/*
359 * ext2_find_entry()
360 *
361 * finds an entry in the specified directory with the wanted name. It
Jérémy Cochoy92e12882009-11-30 17:58:43 +0100362 * returns the page in which the entry was found (as a parameter - res_page),
363 * and the entry itself. Page is returned mapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 * Entry is guaranteed to be valid.
365 */
Al Viroa9885442008-08-24 07:28:39 -0400366struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
367 struct qstr *child, struct page ** res_page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368{
Al Viroa9885442008-08-24 07:28:39 -0400369 const char *name = child->name;
370 int namelen = child->len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
372 unsigned long start, n;
373 unsigned long npages = dir_pages(dir);
374 struct page *page = NULL;
375 struct ext2_inode_info *ei = EXT2_I(dir);
376 ext2_dirent * de;
Eric Sandeenbd395972008-10-15 22:04:02 -0700377 int dir_has_error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378
379 if (npages == 0)
380 goto out;
381
382 /* OFFSET_CACHE */
383 *res_page = NULL;
384
385 start = ei->i_dir_start_lookup;
386 if (start >= npages)
387 start = 0;
388 n = start;
389 do {
390 char *kaddr;
Eric Sandeenbd395972008-10-15 22:04:02 -0700391 page = ext2_get_page(dir, n, dir_has_error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 if (!IS_ERR(page)) {
393 kaddr = page_address(page);
394 de = (ext2_dirent *) kaddr;
395 kaddr += ext2_last_byte(dir, n) - reclen;
396 while ((char *) de <= kaddr) {
397 if (de->rec_len == 0) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700398 ext2_error(dir->i_sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 "zero-length directory entry");
400 ext2_put_page(page);
401 goto out;
402 }
403 if (ext2_match (namelen, name, de))
404 goto found;
405 de = ext2_next_entry(de);
406 }
407 ext2_put_page(page);
Eric Sandeenbd395972008-10-15 22:04:02 -0700408 } else
409 dir_has_error = 1;
410
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 if (++n >= npages)
412 n = 0;
Eric Sandeend8adb9c2007-02-10 01:45:06 -0800413 /* next page is past the blocks we've got */
414 if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700415 ext2_error(dir->i_sb, __func__,
Eric Sandeend8adb9c2007-02-10 01:45:06 -0800416 "dir %lu size %lld exceeds block count %llu",
417 dir->i_ino, dir->i_size,
418 (unsigned long long)dir->i_blocks);
419 goto out;
420 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 } while (n != start);
422out:
423 return NULL;
424
425found:
426 *res_page = page;
427 ei->i_dir_start_lookup = n;
428 return de;
429}
430
431struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
432{
Eric Sandeenbd395972008-10-15 22:04:02 -0700433 struct page *page = ext2_get_page(dir, 0, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 ext2_dirent *de = NULL;
435
436 if (!IS_ERR(page)) {
437 de = ext2_next_entry((ext2_dirent *) page_address(page));
438 *p = page;
439 }
440 return de;
441}
442
Al Viroa9885442008-08-24 07:28:39 -0400443ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444{
445 ino_t res = 0;
Al Viroa9885442008-08-24 07:28:39 -0400446 struct ext2_dir_entry_2 *de;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 struct page *page;
448
Al Viroa9885442008-08-24 07:28:39 -0400449 de = ext2_find_entry (dir, child, &page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 if (de) {
451 res = le32_to_cpu(de->inode);
Evgeniy Dushistov7d93a1a2006-06-25 05:49:27 -0700452 ext2_put_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 }
454 return res;
455}
456
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200457static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
458{
Christoph Hellwig6e1db882010-06-04 11:29:57 +0200459 return __block_write_begin(page, pos, len, ext2_get_block);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200460}
461
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462/* Releases the page */
463void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
Jan Kara39fe7552009-06-17 16:26:20 -0700464 struct page *page, struct inode *inode, int update_times)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465{
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700466 loff_t pos = page_offset(page) +
467 (char *) de - (char *) page_address(page);
Jan Kara89910cc2007-10-21 16:41:40 -0700468 unsigned len = ext2_rec_len_from_disk(de->rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 int err;
470
471 lock_page(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200472 err = ext2_prepare_chunk(page, pos, len);
Eric Sesterhenn309be532006-03-26 18:27:41 +0200473 BUG_ON(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 de->inode = cpu_to_le32(inode->i_ino);
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700475 ext2_set_de_type(de, inode);
476 err = ext2_commit_chunk(page, pos, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 ext2_put_page(page);
Jan Kara39fe7552009-06-17 16:26:20 -0700478 if (update_times)
479 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
481 mark_inode_dirty(dir);
482}
483
484/*
485 * Parent is locked.
486 */
487int ext2_add_link (struct dentry *dentry, struct inode *inode)
488{
David Howells2b0143b2015-03-17 22:25:59 +0000489 struct inode *dir = d_inode(dentry->d_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 const char *name = dentry->d_name.name;
491 int namelen = dentry->d_name.len;
492 unsigned chunk_size = ext2_chunk_size(dir);
493 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
494 unsigned short rec_len, name_len;
495 struct page *page = NULL;
496 ext2_dirent * de;
497 unsigned long npages = dir_pages(dir);
498 unsigned long n;
499 char *kaddr;
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700500 loff_t pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 int err;
502
503 /*
504 * We take care of directory expansion in the same loop.
505 * This code plays outside i_size, so it locks the page
506 * to protect that region.
507 */
508 for (n = 0; n <= npages; n++) {
509 char *dir_end;
510
Eric Sandeenbd395972008-10-15 22:04:02 -0700511 page = ext2_get_page(dir, n, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 err = PTR_ERR(page);
513 if (IS_ERR(page))
514 goto out;
515 lock_page(page);
516 kaddr = page_address(page);
517 dir_end = kaddr + ext2_last_byte(dir, n);
518 de = (ext2_dirent *)kaddr;
519 kaddr += PAGE_CACHE_SIZE - reclen;
520 while ((char *)de <= kaddr) {
521 if ((char *)de == dir_end) {
522 /* We hit i_size */
523 name_len = 0;
524 rec_len = chunk_size;
Jan Kara89910cc2007-10-21 16:41:40 -0700525 de->rec_len = ext2_rec_len_to_disk(chunk_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 de->inode = 0;
527 goto got_it;
528 }
529 if (de->rec_len == 0) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700530 ext2_error(dir->i_sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 "zero-length directory entry");
532 err = -EIO;
533 goto out_unlock;
534 }
535 err = -EEXIST;
536 if (ext2_match (namelen, name, de))
537 goto out_unlock;
538 name_len = EXT2_DIR_REC_LEN(de->name_len);
Jan Kara89910cc2007-10-21 16:41:40 -0700539 rec_len = ext2_rec_len_from_disk(de->rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 if (!de->inode && rec_len >= reclen)
541 goto got_it;
542 if (rec_len >= name_len + reclen)
543 goto got_it;
544 de = (ext2_dirent *) ((char *) de + rec_len);
545 }
546 unlock_page(page);
547 ext2_put_page(page);
548 }
549 BUG();
550 return -EINVAL;
551
552got_it:
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700553 pos = page_offset(page) +
554 (char*)de - (char*)page_address(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200555 err = ext2_prepare_chunk(page, pos, rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 if (err)
557 goto out_unlock;
558 if (de->inode) {
559 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
Jan Kara89910cc2007-10-21 16:41:40 -0700560 de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
561 de->rec_len = ext2_rec_len_to_disk(name_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 de = de1;
563 }
564 de->name_len = namelen;
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700565 memcpy(de->name, name, namelen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 de->inode = cpu_to_le32(inode->i_ino);
567 ext2_set_de_type (de, inode);
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700568 err = ext2_commit_chunk(page, pos, rec_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
570 EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
571 mark_inode_dirty(dir);
572 /* OFFSET_CACHE */
573out_put:
574 ext2_put_page(page);
575out:
576 return err;
577out_unlock:
578 unlock_page(page);
579 goto out_put;
580}
581
582/*
583 * ext2_delete_entry deletes a directory entry by merging it with the
584 * previous entry. Page is up-to-date. Releases the page.
585 */
586int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
587{
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200588 struct inode *inode = page->mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 char *kaddr = page_address(page);
590 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
Jan Kara89910cc2007-10-21 16:41:40 -0700591 unsigned to = ((char *)dir - kaddr) +
592 ext2_rec_len_from_disk(dir->rec_len);
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700593 loff_t pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 ext2_dirent * pde = NULL;
595 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
596 int err;
597
598 while ((char*)de < (char*)dir) {
599 if (de->rec_len == 0) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700600 ext2_error(inode->i_sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 "zero-length directory entry");
602 err = -EIO;
603 goto out;
604 }
605 pde = de;
606 de = ext2_next_entry(de);
607 }
608 if (pde)
609 from = (char*)pde - (char*)page_address(page);
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700610 pos = page_offset(page) + from;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 lock_page(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200612 err = ext2_prepare_chunk(page, pos, to - from);
Eric Sesterhenn309be532006-03-26 18:27:41 +0200613 BUG_ON(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 if (pde)
Jan Kara89910cc2007-10-21 16:41:40 -0700615 pde->rec_len = ext2_rec_len_to_disk(to - from);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 dir->inode = 0;
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700617 err = ext2_commit_chunk(page, pos, to - from);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
619 EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
620 mark_inode_dirty(inode);
621out:
622 ext2_put_page(page);
623 return err;
624}
625
626/*
627 * Set the first fragment of directory.
628 */
629int ext2_make_empty(struct inode *inode, struct inode *parent)
630{
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200631 struct page *page = grab_cache_page(inode->i_mapping, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 unsigned chunk_size = ext2_chunk_size(inode);
633 struct ext2_dir_entry_2 * de;
634 int err;
635 void *kaddr;
636
637 if (!page)
638 return -ENOMEM;
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700639
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200640 err = ext2_prepare_chunk(page, 0, chunk_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 if (err) {
642 unlock_page(page);
643 goto fail;
644 }
Cong Wangd4a23ae2011-11-25 23:14:29 +0800645 kaddr = kmap_atomic(page);
Luiz Fernando Capitulino7823c7c2006-01-11 01:38:27 +0100646 memset(kaddr, 0, chunk_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 de = (struct ext2_dir_entry_2 *)kaddr;
648 de->name_len = 1;
Jan Kara89910cc2007-10-21 16:41:40 -0700649 de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 memcpy (de->name, ".\0\0", 4);
651 de->inode = cpu_to_le32(inode->i_ino);
652 ext2_set_de_type (de, inode);
653
654 de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
655 de->name_len = 2;
Jan Kara89910cc2007-10-21 16:41:40 -0700656 de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 de->inode = cpu_to_le32(parent->i_ino);
658 memcpy (de->name, "..\0", 4);
659 ext2_set_de_type (de, inode);
Cong Wangd4a23ae2011-11-25 23:14:29 +0800660 kunmap_atomic(kaddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 err = ext2_commit_chunk(page, 0, chunk_size);
662fail:
663 page_cache_release(page);
664 return err;
665}
666
667/*
668 * routine to check that the specified directory is empty (for rmdir)
669 */
670int ext2_empty_dir (struct inode * inode)
671{
672 struct page *page = NULL;
673 unsigned long i, npages = dir_pages(inode);
Eric Sandeenbd395972008-10-15 22:04:02 -0700674 int dir_has_error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
676 for (i = 0; i < npages; i++) {
677 char *kaddr;
678 ext2_dirent * de;
Eric Sandeenbd395972008-10-15 22:04:02 -0700679 page = ext2_get_page(inode, i, dir_has_error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680
Eric Sandeenbd395972008-10-15 22:04:02 -0700681 if (IS_ERR(page)) {
682 dir_has_error = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 continue;
Eric Sandeenbd395972008-10-15 22:04:02 -0700684 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685
686 kaddr = page_address(page);
687 de = (ext2_dirent *)kaddr;
688 kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
689
690 while ((char *)de <= kaddr) {
691 if (de->rec_len == 0) {
Harvey Harrison605afd62008-04-28 02:16:03 -0700692 ext2_error(inode->i_sb, __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 "zero-length directory entry");
694 printk("kaddr=%p, de=%p\n", kaddr, de);
695 goto not_empty;
696 }
697 if (de->inode != 0) {
698 /* check for . and .. */
699 if (de->name[0] != '.')
700 goto not_empty;
701 if (de->name_len > 2)
702 goto not_empty;
703 if (de->name_len < 2) {
704 if (de->inode !=
705 cpu_to_le32(inode->i_ino))
706 goto not_empty;
707 } else if (de->name[1] != '.')
708 goto not_empty;
709 }
710 de = ext2_next_entry(de);
711 }
712 ext2_put_page(page);
713 }
714 return 1;
715
716not_empty:
717 ext2_put_page(page);
718 return 0;
719}
720
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800721const struct file_operations ext2_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 .llseek = generic_file_llseek,
723 .read = generic_read_dir,
Al Viro80886292013-05-15 18:51:49 -0400724 .iterate = ext2_readdir,
Andi Kleen14f9f7b2008-02-06 01:40:10 -0800725 .unlocked_ioctl = ext2_ioctl,
David Howellse322ff02006-08-29 19:06:20 +0100726#ifdef CONFIG_COMPAT
727 .compat_ioctl = ext2_compat_ioctl,
728#endif
Jan Kara48bde862009-12-15 16:46:49 -0800729 .fsync = ext2_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730};