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)
11 * linux/fs/minix/dir.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * ext2 directory handling functions
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * All code that works with directory layout had been switched to pagecache
25 #include <linux/ext2_fs.h>
26 #include <linux/pagemap.h>
27 #include <linux/obd_support.h>
28 #include <linux/locks.h>
30 typedef struct ext2_dir_entry_2 ext2_dirent;
32 #define PageChecked(page) test_bit(PG_checked, &(page)->flags)
33 #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
34 #define PG_checked 13 /* kill me in 2.5.<early>. */
36 int waitfor_one_page(struct page *page)
39 struct buffer_head *bh, *head = page->buffers;
44 if (buffer_req(bh) && !buffer_uptodate(bh))
46 } while ((bh = bh->b_this_page) != head);
51 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
52 * more robust, but we have what we have
54 static inline unsigned ext2_chunk_size(struct inode *inode)
56 //return inode->i_sb->s_blocksize;
60 static inline void ext2_put_page(struct page *page)
63 page_cache_release(page);
66 static inline unsigned long dir_pages(struct inode *inode)
68 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
71 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
73 struct inode *dir = page->mapping->host;
75 dir->i_version = ++event;
76 page->mapping->a_ops->commit_write(NULL, page, from, to);
78 err = waitfor_one_page(page);
82 static void ext2_check_page(struct page *page)
84 struct inode *dir = page->mapping->host;
85 struct super_block *sb = dir->i_sb;
86 unsigned chunk_size = ext2_chunk_size(dir);
87 char *kaddr = page_address(page);
88 // u32 max_inumber = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
89 unsigned offs, rec_len;
90 unsigned limit = PAGE_CACHE_SIZE;
94 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
95 limit = dir->i_size & ~PAGE_CACHE_MASK;
96 if (limit & (chunk_size - 1))
98 for (offs = limit; offs<PAGE_CACHE_SIZE; offs += chunk_size) {
99 ext2_dirent *p = (ext2_dirent*)(kaddr + offs);
100 p->rec_len = cpu_to_le16(chunk_size);
105 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
106 p = (ext2_dirent *)(kaddr + offs);
107 rec_len = le16_to_cpu(p->rec_len);
109 if (rec_len < EXT2_DIR_REC_LEN(1))
113 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
115 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
117 // if (le32_to_cpu(p->inode) > max_inumber)
123 SetPageChecked(page);
126 /* Too bad, we had an error */
129 ext2_error(sb, "ext2_check_page",
130 "size of directory #%lu is not a multiple of chunk size",
135 error = "rec_len is smaller than minimal";
138 error = "unaligned directory entry";
141 error = "rec_len is too small for name_len";
144 error = "directory entry across blocks";
147 // error = "inode out of bounds";
149 ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "
150 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
151 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
152 (unsigned long) le32_to_cpu(p->inode),
153 rec_len, p->name_len);
156 p = (ext2_dirent *)(kaddr + offs);
157 ext2_error (sb, "ext2_check_page",
158 "entry in directory #%lu spans the page boundary"
159 "offset=%lu, inode=%lu",
160 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
161 (unsigned long) le32_to_cpu(p->inode));
163 SetPageChecked(page);
167 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
169 struct address_space *mapping = dir->i_mapping;
170 struct page *page = read_cache_page(mapping, n,
171 (filler_t*)mapping->a_ops->readpage, NULL);
175 if (!Page_Uptodate(page))
177 if (!PageChecked(page))
178 ext2_check_page(page);
186 return ERR_PTR(-EIO);
190 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
192 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
194 static inline int ext2_match (int len, const char * const name,
195 struct ext2_dir_entry_2 * de)
197 if (len != de->name_len)
201 return !memcmp(name, de->name, len);
205 * p is at least 6 bytes before the end of page
207 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
209 return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
212 static inline unsigned
213 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
215 ext2_dirent *de = (ext2_dirent*)(base + offset);
216 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
217 while ((char*)p < (char*)de)
218 p = ext2_next_entry(p);
219 return (char *)p - base;
222 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
223 [EXT2_FT_UNKNOWN] DT_UNKNOWN,
224 [EXT2_FT_REG_FILE] DT_REG,
225 [EXT2_FT_DIR] DT_DIR,
226 [EXT2_FT_CHRDEV] DT_CHR,
227 [EXT2_FT_BLKDEV] DT_BLK,
228 [EXT2_FT_FIFO] DT_FIFO,
229 [EXT2_FT_SOCK] DT_SOCK,
230 [EXT2_FT_SYMLINK] DT_LNK,
234 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
235 [S_IFREG >> S_SHIFT] EXT2_FT_REG_FILE,
236 [S_IFDIR >> S_SHIFT] EXT2_FT_DIR,
237 [S_IFCHR >> S_SHIFT] EXT2_FT_CHRDEV,
238 [S_IFBLK >> S_SHIFT] EXT2_FT_BLKDEV,
239 [S_IFIFO >> S_SHIFT] EXT2_FT_FIFO,
240 [S_IFSOCK >> S_SHIFT] EXT2_FT_SOCK,
241 [S_IFLNK >> S_SHIFT] EXT2_FT_SYMLINK,
244 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
247 mode_t mode = inode->i_mode;
248 if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
249 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
257 new_obdfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
259 loff_t pos = filp->f_pos;
260 struct inode *inode = filp->f_dentry->d_inode;
261 // XXX struct super_block *sb = inode->i_sb;
262 unsigned offset = pos & ~PAGE_CACHE_MASK;
263 unsigned long n = pos >> PAGE_CACHE_SHIFT;
264 unsigned long npages = dir_pages(inode);
265 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
266 unsigned char *types = NULL;
267 int need_revalidate = (filp->f_version != inode->i_version);
269 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
272 //if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
273 //types = ext2_filetype_table;
275 for ( ; n < npages; n++, offset = 0) {
278 struct page *page = ext2_get_page(inode, n);
282 kaddr = page_address(page);
283 if (need_revalidate) {
284 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
287 de = (ext2_dirent *)(kaddr+offset);
288 limit = kaddr + PAGE_CACHE_SIZE - EXT2_DIR_REC_LEN(1);
289 for ( ;(char*)de <= limit; de = ext2_next_entry(de))
292 unsigned char d_type = DT_UNKNOWN;
294 if (types && de->file_type < EXT2_FT_MAX)
295 d_type = types[de->file_type];
297 offset = (char *)de - kaddr;
298 over = filldir(dirent, de->name, de->name_len,
299 (n<<PAGE_CACHE_SHIFT) | offset,
300 le32_to_cpu(de->inode), d_type);
310 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
311 filp->f_version = inode->i_version;
319 * finds an entry in the specified directory with the wanted name. It
320 * returns the page in which the entry was found, and the entry itself
321 * (as a parameter - res_dir). Page is returned mapped and unlocked.
322 * Entry is guaranteed to be valid.
324 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
325 struct dentry *dentry, struct page ** res_page)
327 const char *name = dentry->d_name.name;
328 int namelen = dentry->d_name.len;
329 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
330 unsigned long start, n;
331 unsigned long npages = dir_pages(dir);
332 struct page *page = NULL;
338 // start = dir->u.ext2_i.i_dir_start_lookup;
345 page = ext2_get_page(dir, n);
347 kaddr = page_address(page);
348 de = (ext2_dirent *) kaddr;
349 kaddr += PAGE_CACHE_SIZE - reclen;
350 while ((char *) de <= kaddr) {
351 if (ext2_match (namelen, name, de))
353 de = ext2_next_entry(de);
359 } while (n != start);
364 // dir->u.ext2_i.i_dir_start_lookup = n;
368 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
370 struct page *page = ext2_get_page(dir, 0);
371 ext2_dirent *de = NULL;
374 de = ext2_next_entry((ext2_dirent *) page_address(page));
380 ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry)
383 struct ext2_dir_entry_2 * de;
386 de = ext2_find_entry (dir, dentry, &page);
388 res = le32_to_cpu(de->inode);
390 page_cache_release(page);
395 /* Releases the page */
396 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
397 struct page *page, struct inode *inode)
399 unsigned from = (char *) de - (char *) page_address(page);
400 unsigned to = from + le16_to_cpu(de->rec_len);
404 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
407 de->inode = cpu_to_le32(inode->i_ino);
408 ext2_set_de_type (de, inode);
409 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
410 err = ext2_commit_chunk(page, from, to);
418 int ext2_add_link (struct dentry *dentry, struct inode *inode)
420 struct inode *dir = dentry->d_parent->d_inode;
421 const char *name = dentry->d_name.name;
422 int namelen = dentry->d_name.len;
423 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
424 unsigned short rec_len, name_len;
425 struct page *page = NULL;
427 unsigned long npages = dir_pages(dir);
433 /* We take care of directory expansion in the same loop */
434 for (n = 0; n <= npages; n++) {
435 page = ext2_get_page(dir, n);
439 kaddr = page_address(page);
440 de = (ext2_dirent *)kaddr;
441 kaddr += PAGE_CACHE_SIZE - reclen;
442 while ((char *)de <= kaddr) {
444 if (ext2_match (namelen, name, de))
446 name_len = EXT2_DIR_REC_LEN(de->name_len);
447 rec_len = le16_to_cpu(de->rec_len);
448 if ( n==npages && rec_len == 0) {
449 printk("Fatal dir behaviour\n");
452 if (!de->inode && rec_len >= reclen)
454 if (rec_len >= name_len + reclen)
456 de = (ext2_dirent *) ((char *) de + rec_len);
464 from = (char*)de - (char*)page_address(page);
467 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
471 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
472 de1->rec_len = cpu_to_le16(rec_len - name_len);
473 de->rec_len = cpu_to_le16(name_len);
476 de->name_len = namelen;
477 memcpy (de->name, name, namelen);
478 de->inode = cpu_to_le32(inode->i_ino);
479 ext2_set_de_type (de, inode);
480 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
481 err = ext2_commit_chunk(page, from, to);
483 // change_inode happens with the commit_chunk
484 // obdfs_change_inode(dir);
495 * ext2_delete_entry deletes a directory entry by merging it with the
496 * previous entry. Page is up-to-date. Releases the page.
498 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
500 struct address_space *mapping = page->mapping;
501 struct inode *inode = mapping->host;
502 char *kaddr = page_address(page);
503 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
504 unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
505 ext2_dirent * pde = NULL;
506 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
509 while ((char*)de < (char*)dir) {
511 de = ext2_next_entry(de);
514 from = (char*)pde - (char*)page_address(page);
516 err = mapping->a_ops->prepare_write(NULL, page, from, to);
520 pde->rec_len = cpu_to_le16(to-from);
522 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
523 err = ext2_commit_chunk(page, from, to);
530 * Set the first fragment of directory.
532 int ext2_make_empty(struct inode *inode, struct inode *parent)
534 struct address_space *mapping = inode->i_mapping;
535 struct page *page = grab_cache_page(mapping, 0);
536 unsigned chunk_size = ext2_chunk_size(inode);
537 struct ext2_dir_entry_2 * de;
543 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
547 base = page_address(page);
549 de = (struct ext2_dir_entry_2 *) base;
551 de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
552 memcpy (de->name, ".\0\0", 4);
553 de->inode = cpu_to_le32(inode->i_ino);
554 ext2_set_de_type (de, inode);
556 de = (struct ext2_dir_entry_2 *) (base + EXT2_DIR_REC_LEN(1));
558 de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
559 de->inode = cpu_to_le32(parent->i_ino);
560 memcpy (de->name, "..\0", 4);
561 ext2_set_de_type (de, inode);
563 err = ext2_commit_chunk(page, 0, chunk_size);
566 page_cache_release(page);
571 * routine to check that the specified directory is empty (for rmdir)
573 int ext2_empty_dir (struct inode * inode)
575 struct page *page = NULL;
576 unsigned long i, npages = dir_pages(inode);
578 for (i = 0; i < npages; i++) {
581 page = ext2_get_page(inode, i);
586 kaddr = page_address(page);
587 de = (ext2_dirent *)kaddr;
588 kaddr += PAGE_CACHE_SIZE-EXT2_DIR_REC_LEN(1);
590 while ((char *)de <= kaddr) {
591 if (de->inode != 0) {
592 /* check for . and .. */
593 if (de->name[0] != '.')
595 if (de->name_len > 2)
597 if (de->name_len < 2) {
599 cpu_to_le32(inode->i_ino))
601 } else if (de->name[1] != '.')
604 de = ext2_next_entry(de);
615 struct file_operations obdfs_dir_operations = {
616 read: generic_read_dir,
617 readdir: new_obdfs_readdir