dir.c 18 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728
  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * linux/fs/ext2/dir.c
  4. *
  5. * Copyright (C) 1992, 1993, 1994, 1995
  6. * Remy Card ([email protected])
  7. * Laboratoire MASI - Institut Blaise Pascal
  8. * Universite Pierre et Marie Curie (Paris VI)
  9. *
  10. * from
  11. *
  12. * linux/fs/minix/dir.c
  13. *
  14. * Copyright (C) 1991, 1992 Linus Torvalds
  15. *
  16. * ext2 directory handling functions
  17. *
  18. * Big-endian to little-endian byte-swapping/bitmaps by
  19. * David S. Miller ([email protected]), 1995
  20. *
  21. * All code that works with directory layout had been switched to pagecache
  22. * and moved here. AV
  23. */
  24. #include "ext2.h"
  25. #include <linux/buffer_head.h>
  26. #include <linux/pagemap.h>
  27. #include <linux/swap.h>
  28. #include <linux/iversion.h>
  29. typedef struct ext2_dir_entry_2 ext2_dirent;
  30. /*
  31. * Tests against MAX_REC_LEN etc were put in place for 64k block
  32. * sizes; if that is not possible on this arch, we can skip
  33. * those tests and speed things up.
  34. */
  35. static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
  36. {
  37. unsigned len = le16_to_cpu(dlen);
  38. #if (PAGE_SIZE >= 65536)
  39. if (len == EXT2_MAX_REC_LEN)
  40. return 1 << 16;
  41. #endif
  42. return len;
  43. }
  44. static inline __le16 ext2_rec_len_to_disk(unsigned len)
  45. {
  46. #if (PAGE_SIZE >= 65536)
  47. if (len == (1 << 16))
  48. return cpu_to_le16(EXT2_MAX_REC_LEN);
  49. else
  50. BUG_ON(len > (1 << 16));
  51. #endif
  52. return cpu_to_le16(len);
  53. }
  54. /*
  55. * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
  56. * more robust, but we have what we have
  57. */
  58. static inline unsigned ext2_chunk_size(struct inode *inode)
  59. {
  60. return inode->i_sb->s_blocksize;
  61. }
  62. /*
  63. * Return the offset into page `page_nr' of the last valid
  64. * byte in that page, plus one.
  65. */
  66. static unsigned
  67. ext2_last_byte(struct inode *inode, unsigned long page_nr)
  68. {
  69. unsigned last_byte = inode->i_size;
  70. last_byte -= page_nr << PAGE_SHIFT;
  71. if (last_byte > PAGE_SIZE)
  72. last_byte = PAGE_SIZE;
  73. return last_byte;
  74. }
  75. static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
  76. {
  77. struct address_space *mapping = page->mapping;
  78. struct inode *dir = mapping->host;
  79. int err = 0;
  80. inode_inc_iversion(dir);
  81. block_write_end(NULL, mapping, pos, len, len, page, NULL);
  82. if (pos+len > dir->i_size) {
  83. i_size_write(dir, pos+len);
  84. mark_inode_dirty(dir);
  85. }
  86. if (IS_DIRSYNC(dir)) {
  87. err = write_one_page(page);
  88. if (!err)
  89. err = sync_inode_metadata(dir, 1);
  90. } else {
  91. unlock_page(page);
  92. }
  93. return err;
  94. }
  95. static bool ext2_check_page(struct page *page, int quiet, char *kaddr)
  96. {
  97. struct inode *dir = page->mapping->host;
  98. struct super_block *sb = dir->i_sb;
  99. unsigned chunk_size = ext2_chunk_size(dir);
  100. u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
  101. unsigned offs, rec_len;
  102. unsigned limit = PAGE_SIZE;
  103. ext2_dirent *p;
  104. char *error;
  105. if ((dir->i_size >> PAGE_SHIFT) == page->index) {
  106. limit = dir->i_size & ~PAGE_MASK;
  107. if (limit & (chunk_size - 1))
  108. goto Ebadsize;
  109. if (!limit)
  110. goto out;
  111. }
  112. for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
  113. p = (ext2_dirent *)(kaddr + offs);
  114. rec_len = ext2_rec_len_from_disk(p->rec_len);
  115. if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
  116. goto Eshort;
  117. if (unlikely(rec_len & 3))
  118. goto Ealign;
  119. if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
  120. goto Enamelen;
  121. if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
  122. goto Espan;
  123. if (unlikely(le32_to_cpu(p->inode) > max_inumber))
  124. goto Einumber;
  125. }
  126. if (offs != limit)
  127. goto Eend;
  128. out:
  129. SetPageChecked(page);
  130. return true;
  131. /* Too bad, we had an error */
  132. Ebadsize:
  133. if (!quiet)
  134. ext2_error(sb, __func__,
  135. "size of directory #%lu is not a multiple "
  136. "of chunk size", dir->i_ino);
  137. goto fail;
  138. Eshort:
  139. error = "rec_len is smaller than minimal";
  140. goto bad_entry;
  141. Ealign:
  142. error = "unaligned directory entry";
  143. goto bad_entry;
  144. Enamelen:
  145. error = "rec_len is too small for name_len";
  146. goto bad_entry;
  147. Espan:
  148. error = "directory entry across blocks";
  149. goto bad_entry;
  150. Einumber:
  151. error = "inode out of bounds";
  152. bad_entry:
  153. if (!quiet)
  154. ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
  155. "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
  156. dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
  157. (unsigned long) le32_to_cpu(p->inode),
  158. rec_len, p->name_len);
  159. goto fail;
  160. Eend:
  161. if (!quiet) {
  162. p = (ext2_dirent *)(kaddr + offs);
  163. ext2_error(sb, "ext2_check_page",
  164. "entry in directory #%lu spans the page boundary"
  165. "offset=%lu, inode=%lu",
  166. dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
  167. (unsigned long) le32_to_cpu(p->inode));
  168. }
  169. fail:
  170. SetPageError(page);
  171. return false;
  172. }
  173. /*
  174. * Calls to ext2_get_page()/ext2_put_page() must be nested according to the
  175. * rules documented in kmap_local_page()/kunmap_local().
  176. *
  177. * NOTE: ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page()
  178. * and should be treated as a call to ext2_get_page() for nesting purposes.
  179. */
  180. static struct page * ext2_get_page(struct inode *dir, unsigned long n,
  181. int quiet, void **page_addr)
  182. {
  183. struct address_space *mapping = dir->i_mapping;
  184. struct folio *folio = read_mapping_folio(mapping, n, NULL);
  185. if (IS_ERR(folio))
  186. return &folio->page;
  187. *page_addr = kmap_local_folio(folio, n & (folio_nr_pages(folio) - 1));
  188. if (unlikely(!folio_test_checked(folio))) {
  189. if (!ext2_check_page(&folio->page, quiet, *page_addr))
  190. goto fail;
  191. }
  192. return &folio->page;
  193. fail:
  194. ext2_put_page(&folio->page, *page_addr);
  195. return ERR_PTR(-EIO);
  196. }
  197. /*
  198. * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
  199. *
  200. * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
  201. */
  202. static inline int ext2_match (int len, const char * const name,
  203. struct ext2_dir_entry_2 * de)
  204. {
  205. if (len != de->name_len)
  206. return 0;
  207. if (!de->inode)
  208. return 0;
  209. return !memcmp(name, de->name, len);
  210. }
  211. /*
  212. * p is at least 6 bytes before the end of page
  213. */
  214. static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
  215. {
  216. return (ext2_dirent *)((char *)p +
  217. ext2_rec_len_from_disk(p->rec_len));
  218. }
  219. static inline unsigned
  220. ext2_validate_entry(char *base, unsigned offset, unsigned mask)
  221. {
  222. ext2_dirent *de = (ext2_dirent*)(base + offset);
  223. ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
  224. while ((char*)p < (char*)de) {
  225. if (p->rec_len == 0)
  226. break;
  227. p = ext2_next_entry(p);
  228. }
  229. return (char *)p - base;
  230. }
  231. static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
  232. {
  233. if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
  234. de->file_type = fs_umode_to_ftype(inode->i_mode);
  235. else
  236. de->file_type = 0;
  237. }
  238. static int
  239. ext2_readdir(struct file *file, struct dir_context *ctx)
  240. {
  241. loff_t pos = ctx->pos;
  242. struct inode *inode = file_inode(file);
  243. struct super_block *sb = inode->i_sb;
  244. unsigned int offset = pos & ~PAGE_MASK;
  245. unsigned long n = pos >> PAGE_SHIFT;
  246. unsigned long npages = dir_pages(inode);
  247. unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
  248. bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
  249. bool has_filetype;
  250. if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
  251. return 0;
  252. has_filetype =
  253. EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE);
  254. for ( ; n < npages; n++, offset = 0) {
  255. char *kaddr, *limit;
  256. ext2_dirent *de;
  257. struct page *page = ext2_get_page(inode, n, 0, (void **)&kaddr);
  258. if (IS_ERR(page)) {
  259. ext2_error(sb, __func__,
  260. "bad page in #%lu",
  261. inode->i_ino);
  262. ctx->pos += PAGE_SIZE - offset;
  263. return PTR_ERR(page);
  264. }
  265. if (unlikely(need_revalidate)) {
  266. if (offset) {
  267. offset = ext2_validate_entry(kaddr, offset, chunk_mask);
  268. ctx->pos = (n<<PAGE_SHIFT) + offset;
  269. }
  270. file->f_version = inode_query_iversion(inode);
  271. need_revalidate = false;
  272. }
  273. de = (ext2_dirent *)(kaddr+offset);
  274. limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
  275. for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
  276. if (de->rec_len == 0) {
  277. ext2_error(sb, __func__,
  278. "zero-length directory entry");
  279. ext2_put_page(page, kaddr);
  280. return -EIO;
  281. }
  282. if (de->inode) {
  283. unsigned char d_type = DT_UNKNOWN;
  284. if (has_filetype)
  285. d_type = fs_ftype_to_dtype(de->file_type);
  286. if (!dir_emit(ctx, de->name, de->name_len,
  287. le32_to_cpu(de->inode),
  288. d_type)) {
  289. ext2_put_page(page, kaddr);
  290. return 0;
  291. }
  292. }
  293. ctx->pos += ext2_rec_len_from_disk(de->rec_len);
  294. }
  295. ext2_put_page(page, kaddr);
  296. }
  297. return 0;
  298. }
  299. /*
  300. * ext2_find_entry()
  301. *
  302. * finds an entry in the specified directory with the wanted name. It
  303. * returns the page in which the entry was found (as a parameter - res_page),
  304. * and the entry itself. Page is returned mapped and unlocked.
  305. * Entry is guaranteed to be valid.
  306. *
  307. * On Success ext2_put_page() should be called on *res_page.
  308. *
  309. * NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to
  310. * the rules documented in kmap_local_page()/kunmap_local().
  311. *
  312. * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and
  313. * should be treated as a call to ext2_get_page() for nesting purposes.
  314. */
  315. struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
  316. const struct qstr *child, struct page **res_page,
  317. void **res_page_addr)
  318. {
  319. const char *name = child->name;
  320. int namelen = child->len;
  321. unsigned reclen = EXT2_DIR_REC_LEN(namelen);
  322. unsigned long start, n;
  323. unsigned long npages = dir_pages(dir);
  324. struct page *page = NULL;
  325. struct ext2_inode_info *ei = EXT2_I(dir);
  326. ext2_dirent * de;
  327. void *page_addr;
  328. if (npages == 0)
  329. goto out;
  330. /* OFFSET_CACHE */
  331. *res_page = NULL;
  332. *res_page_addr = NULL;
  333. start = ei->i_dir_start_lookup;
  334. if (start >= npages)
  335. start = 0;
  336. n = start;
  337. do {
  338. char *kaddr;
  339. page = ext2_get_page(dir, n, 0, &page_addr);
  340. if (IS_ERR(page))
  341. return ERR_CAST(page);
  342. kaddr = page_addr;
  343. de = (ext2_dirent *) kaddr;
  344. kaddr += ext2_last_byte(dir, n) - reclen;
  345. while ((char *) de <= kaddr) {
  346. if (de->rec_len == 0) {
  347. ext2_error(dir->i_sb, __func__,
  348. "zero-length directory entry");
  349. ext2_put_page(page, page_addr);
  350. goto out;
  351. }
  352. if (ext2_match(namelen, name, de))
  353. goto found;
  354. de = ext2_next_entry(de);
  355. }
  356. ext2_put_page(page, page_addr);
  357. if (++n >= npages)
  358. n = 0;
  359. /* next page is past the blocks we've got */
  360. if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) {
  361. ext2_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);
  365. goto out;
  366. }
  367. } while (n != start);
  368. out:
  369. return ERR_PTR(-ENOENT);
  370. found:
  371. *res_page = page;
  372. *res_page_addr = page_addr;
  373. ei->i_dir_start_lookup = n;
  374. return de;
  375. }
  376. /**
  377. * Return the '..' directory entry and the page in which the entry was found
  378. * (as a parameter - p).
  379. *
  380. * On Success ext2_put_page() should be called on *p.
  381. *
  382. * NOTE: Calls to ext2_get_page()/ext2_put_page() must be nested according to
  383. * the rules documented in kmap_local_page()/kunmap_local().
  384. *
  385. * ext2_find_entry() and ext2_dotdot() act as a call to ext2_get_page() and
  386. * should be treated as a call to ext2_get_page() for nesting purposes.
  387. */
  388. struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct page **p,
  389. void **pa)
  390. {
  391. void *page_addr;
  392. struct page *page = ext2_get_page(dir, 0, 0, &page_addr);
  393. ext2_dirent *de = NULL;
  394. if (!IS_ERR(page)) {
  395. de = ext2_next_entry((ext2_dirent *) page_addr);
  396. *p = page;
  397. *pa = page_addr;
  398. }
  399. return de;
  400. }
  401. int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino)
  402. {
  403. struct ext2_dir_entry_2 *de;
  404. struct page *page;
  405. void *page_addr;
  406. de = ext2_find_entry(dir, child, &page, &page_addr);
  407. if (IS_ERR(de))
  408. return PTR_ERR(de);
  409. *ino = le32_to_cpu(de->inode);
  410. ext2_put_page(page, page_addr);
  411. return 0;
  412. }
  413. static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
  414. {
  415. return __block_write_begin(page, pos, len, ext2_get_block);
  416. }
  417. void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
  418. struct page *page, void *page_addr, struct inode *inode,
  419. int update_times)
  420. {
  421. loff_t pos = page_offset(page) +
  422. (char *) de - (char *) page_addr;
  423. unsigned len = ext2_rec_len_from_disk(de->rec_len);
  424. int err;
  425. lock_page(page);
  426. err = ext2_prepare_chunk(page, pos, len);
  427. BUG_ON(err);
  428. de->inode = cpu_to_le32(inode->i_ino);
  429. ext2_set_de_type(de, inode);
  430. err = ext2_commit_chunk(page, pos, len);
  431. if (update_times)
  432. dir->i_mtime = dir->i_ctime = current_time(dir);
  433. EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
  434. mark_inode_dirty(dir);
  435. }
  436. /*
  437. * Parent is locked.
  438. */
  439. int ext2_add_link (struct dentry *dentry, struct inode *inode)
  440. {
  441. struct inode *dir = d_inode(dentry->d_parent);
  442. const char *name = dentry->d_name.name;
  443. int namelen = dentry->d_name.len;
  444. unsigned chunk_size = ext2_chunk_size(dir);
  445. unsigned reclen = EXT2_DIR_REC_LEN(namelen);
  446. unsigned short rec_len, name_len;
  447. struct page *page = NULL;
  448. void *page_addr = NULL;
  449. ext2_dirent * de;
  450. unsigned long npages = dir_pages(dir);
  451. unsigned long n;
  452. loff_t pos;
  453. int err;
  454. /*
  455. * We take care of directory expansion in the same loop.
  456. * This code plays outside i_size, so it locks the page
  457. * to protect that region.
  458. */
  459. for (n = 0; n <= npages; n++) {
  460. char *kaddr;
  461. char *dir_end;
  462. page = ext2_get_page(dir, n, 0, &page_addr);
  463. err = PTR_ERR(page);
  464. if (IS_ERR(page))
  465. goto out;
  466. lock_page(page);
  467. kaddr = page_addr;
  468. dir_end = kaddr + ext2_last_byte(dir, n);
  469. de = (ext2_dirent *)kaddr;
  470. kaddr += PAGE_SIZE - reclen;
  471. while ((char *)de <= kaddr) {
  472. if ((char *)de == dir_end) {
  473. /* We hit i_size */
  474. name_len = 0;
  475. rec_len = chunk_size;
  476. de->rec_len = ext2_rec_len_to_disk(chunk_size);
  477. de->inode = 0;
  478. goto got_it;
  479. }
  480. if (de->rec_len == 0) {
  481. ext2_error(dir->i_sb, __func__,
  482. "zero-length directory entry");
  483. err = -EIO;
  484. goto out_unlock;
  485. }
  486. err = -EEXIST;
  487. if (ext2_match (namelen, name, de))
  488. goto out_unlock;
  489. name_len = EXT2_DIR_REC_LEN(de->name_len);
  490. rec_len = ext2_rec_len_from_disk(de->rec_len);
  491. if (!de->inode && rec_len >= reclen)
  492. goto got_it;
  493. if (rec_len >= name_len + reclen)
  494. goto got_it;
  495. de = (ext2_dirent *) ((char *) de + rec_len);
  496. }
  497. unlock_page(page);
  498. ext2_put_page(page, page_addr);
  499. }
  500. BUG();
  501. return -EINVAL;
  502. got_it:
  503. pos = page_offset(page) +
  504. (char *)de - (char *)page_addr;
  505. err = ext2_prepare_chunk(page, pos, rec_len);
  506. if (err)
  507. goto out_unlock;
  508. if (de->inode) {
  509. ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
  510. de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
  511. de->rec_len = ext2_rec_len_to_disk(name_len);
  512. de = de1;
  513. }
  514. de->name_len = namelen;
  515. memcpy(de->name, name, namelen);
  516. de->inode = cpu_to_le32(inode->i_ino);
  517. ext2_set_de_type (de, inode);
  518. err = ext2_commit_chunk(page, pos, rec_len);
  519. dir->i_mtime = dir->i_ctime = current_time(dir);
  520. EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
  521. mark_inode_dirty(dir);
  522. /* OFFSET_CACHE */
  523. out_put:
  524. ext2_put_page(page, page_addr);
  525. out:
  526. return err;
  527. out_unlock:
  528. unlock_page(page);
  529. goto out_put;
  530. }
  531. /*
  532. * ext2_delete_entry deletes a directory entry by merging it with the
  533. * previous entry. Page is up-to-date.
  534. */
  535. int ext2_delete_entry (struct ext2_dir_entry_2 *dir, struct page *page,
  536. char *kaddr)
  537. {
  538. struct inode *inode = page->mapping->host;
  539. unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
  540. unsigned to = ((char *)dir - kaddr) +
  541. ext2_rec_len_from_disk(dir->rec_len);
  542. loff_t pos;
  543. ext2_dirent * pde = NULL;
  544. ext2_dirent * de = (ext2_dirent *) (kaddr + from);
  545. int err;
  546. while ((char*)de < (char*)dir) {
  547. if (de->rec_len == 0) {
  548. ext2_error(inode->i_sb, __func__,
  549. "zero-length directory entry");
  550. err = -EIO;
  551. goto out;
  552. }
  553. pde = de;
  554. de = ext2_next_entry(de);
  555. }
  556. if (pde)
  557. from = (char *)pde - kaddr;
  558. pos = page_offset(page) + from;
  559. lock_page(page);
  560. err = ext2_prepare_chunk(page, pos, to - from);
  561. BUG_ON(err);
  562. if (pde)
  563. pde->rec_len = ext2_rec_len_to_disk(to - from);
  564. dir->inode = 0;
  565. err = ext2_commit_chunk(page, pos, to - from);
  566. inode->i_ctime = inode->i_mtime = current_time(inode);
  567. EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
  568. mark_inode_dirty(inode);
  569. out:
  570. return err;
  571. }
  572. /*
  573. * Set the first fragment of directory.
  574. */
  575. int ext2_make_empty(struct inode *inode, struct inode *parent)
  576. {
  577. struct page *page = grab_cache_page(inode->i_mapping, 0);
  578. unsigned chunk_size = ext2_chunk_size(inode);
  579. struct ext2_dir_entry_2 * de;
  580. int err;
  581. void *kaddr;
  582. if (!page)
  583. return -ENOMEM;
  584. err = ext2_prepare_chunk(page, 0, chunk_size);
  585. if (err) {
  586. unlock_page(page);
  587. goto fail;
  588. }
  589. kaddr = kmap_atomic(page);
  590. memset(kaddr, 0, chunk_size);
  591. de = (struct ext2_dir_entry_2 *)kaddr;
  592. de->name_len = 1;
  593. de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
  594. memcpy (de->name, ".\0\0", 4);
  595. de->inode = cpu_to_le32(inode->i_ino);
  596. ext2_set_de_type (de, inode);
  597. de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
  598. de->name_len = 2;
  599. de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
  600. de->inode = cpu_to_le32(parent->i_ino);
  601. memcpy (de->name, "..\0", 4);
  602. ext2_set_de_type (de, inode);
  603. kunmap_atomic(kaddr);
  604. err = ext2_commit_chunk(page, 0, chunk_size);
  605. fail:
  606. put_page(page);
  607. return err;
  608. }
  609. /*
  610. * routine to check that the specified directory is empty (for rmdir)
  611. */
  612. int ext2_empty_dir (struct inode * inode)
  613. {
  614. void *page_addr = NULL;
  615. struct page *page = NULL;
  616. unsigned long i, npages = dir_pages(inode);
  617. for (i = 0; i < npages; i++) {
  618. char *kaddr;
  619. ext2_dirent * de;
  620. page = ext2_get_page(inode, i, 0, &page_addr);
  621. if (IS_ERR(page))
  622. return 0;
  623. kaddr = page_addr;
  624. de = (ext2_dirent *)kaddr;
  625. kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
  626. while ((char *)de <= kaddr) {
  627. if (de->rec_len == 0) {
  628. ext2_error(inode->i_sb, __func__,
  629. "zero-length directory entry");
  630. printk("kaddr=%p, de=%p\n", kaddr, de);
  631. goto not_empty;
  632. }
  633. if (de->inode != 0) {
  634. /* check for . and .. */
  635. if (de->name[0] != '.')
  636. goto not_empty;
  637. if (de->name_len > 2)
  638. goto not_empty;
  639. if (de->name_len < 2) {
  640. if (de->inode !=
  641. cpu_to_le32(inode->i_ino))
  642. goto not_empty;
  643. } else if (de->name[1] != '.')
  644. goto not_empty;
  645. }
  646. de = ext2_next_entry(de);
  647. }
  648. ext2_put_page(page, page_addr);
  649. }
  650. return 1;
  651. not_empty:
  652. ext2_put_page(page, page_addr);
  653. return 0;
  654. }
  655. const struct file_operations ext2_dir_operations = {
  656. .llseek = generic_file_llseek,
  657. .read = generic_read_dir,
  658. .iterate_shared = ext2_readdir,
  659. .unlocked_ioctl = ext2_ioctl,
  660. #ifdef CONFIG_COMPAT
  661. .compat_ioctl = ext2_compat_ioctl,
  662. #endif
  663. .fsync = ext2_fsync,
  664. };