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>
28 #define DEBUG_SUBSYSTEM S_OBDFS
30 #include <linux/obd_support.h>
31 #include <linux/locks.h>
33 typedef struct ext2_dir_entry_2 ext2_dirent;
35 #define PageChecked(page) test_bit(PG_checked, &(page)->flags)
36 #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
38 int waitfor_one_page(struct page *page)
41 struct buffer_head *bh, *head = page->buffers;
46 if (buffer_req(bh) && !buffer_uptodate(bh))
48 } while ((bh = bh->b_this_page) != head);
53 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
54 * more robust, but we have what we have
56 static inline unsigned ext2_chunk_size(struct inode *inode)
58 //return inode->i_sb->s_blocksize;
62 static inline void ext2_put_page(struct page *page)
65 page_cache_release(page);
68 static inline unsigned long dir_pages(struct inode *inode)
70 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
73 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
75 struct inode *dir = page->mapping->host;
77 dir->i_version = ++event;
78 page->mapping->a_ops->commit_write(NULL, page, from, to);
80 err = waitfor_one_page(page);
84 static void ext2_check_page(struct page *page)
86 struct inode *dir = page->mapping->host;
87 unsigned chunk_size = ext2_chunk_size(dir);
88 char *kaddr = page_address(page);
89 // u32 max_inumber = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
90 unsigned offs, rec_len;
91 unsigned limit = PAGE_CACHE_SIZE;
95 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
96 limit = dir->i_size & ~PAGE_CACHE_MASK;
97 if (limit & (chunk_size - 1))
99 for (offs = limit; offs<PAGE_CACHE_SIZE; offs += chunk_size) {
100 ext2_dirent *p = (ext2_dirent*)(kaddr + offs);
101 p->rec_len = cpu_to_le16(chunk_size);
106 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
107 p = (ext2_dirent *)(kaddr + offs);
108 rec_len = le16_to_cpu(p->rec_len);
110 if (rec_len < EXT2_DIR_REC_LEN(1))
114 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
116 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
118 // if (le32_to_cpu(p->inode) > max_inumber)
124 SetPageChecked(page);
127 /* Too bad, we had an error */
130 CERROR("ext2_check_page"
131 "size of directory #%lu is not a multiple of chunk size",
136 error = "rec_len is smaller than minimal";
139 error = "unaligned directory entry";
142 error = "rec_len is too small for name_len";
145 error = "directory entry across blocks";
148 // error = "inode out of bounds";
150 CERROR("ext2_check_page" "bad entry in directory #%lu: %s - "
151 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
152 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
153 (unsigned long) le32_to_cpu(p->inode),
154 rec_len, p->name_len);
157 p = (ext2_dirent *)(kaddr + offs);
158 CERROR("ext2_check_page"
159 "entry in directory #%lu spans the page boundary"
160 "offset=%lu, inode=%lu",
161 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
162 (unsigned long) le32_to_cpu(p->inode));
164 SetPageChecked(page);
168 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
170 struct address_space *mapping = dir->i_mapping;
171 struct page *page = read_cache_page(mapping, n,
172 (filler_t*)mapping->a_ops->readpage, NULL);
176 if (!Page_Uptodate(page))
178 if (!PageChecked(page))
179 ext2_check_page(page);
187 return ERR_PTR(-EIO);
191 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
193 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
195 static inline int ext2_match (int len, const char * const name,
196 struct ext2_dir_entry_2 * de)
198 if (len != de->name_len)
202 return !memcmp(name, de->name, len);
206 * p is at least 6 bytes before the end of page
208 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
210 return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
213 static inline unsigned
214 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
216 ext2_dirent *de = (ext2_dirent*)(base + offset);
217 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
218 while ((char*)p < (char*)de)
219 p = ext2_next_entry(p);
220 return (char *)p - base;
223 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
224 [EXT2_FT_UNKNOWN] DT_UNKNOWN,
225 [EXT2_FT_REG_FILE] DT_REG,
226 [EXT2_FT_DIR] DT_DIR,
227 [EXT2_FT_CHRDEV] DT_CHR,
228 [EXT2_FT_BLKDEV] DT_BLK,
229 [EXT2_FT_FIFO] DT_FIFO,
230 [EXT2_FT_SOCK] DT_SOCK,
231 [EXT2_FT_SYMLINK] DT_LNK,
234 static unsigned int obdfs_dt2fmt[DT_WHT + 1] = {
236 [EXT2_FT_REG_FILE] S_IFREG,
237 [EXT2_FT_DIR] S_IFDIR,
238 [EXT2_FT_CHRDEV] S_IFCHR,
239 [EXT2_FT_BLKDEV] S_IFBLK,
240 [EXT2_FT_FIFO] S_IFIFO,
241 [EXT2_FT_SOCK] S_IFSOCK,
242 [EXT2_FT_SYMLINK] S_IFLNK
246 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
247 [S_IFREG >> S_SHIFT] EXT2_FT_REG_FILE,
248 [S_IFDIR >> S_SHIFT] EXT2_FT_DIR,
249 [S_IFCHR >> S_SHIFT] EXT2_FT_CHRDEV,
250 [S_IFBLK >> S_SHIFT] EXT2_FT_BLKDEV,
251 [S_IFIFO >> S_SHIFT] EXT2_FT_FIFO,
252 [S_IFSOCK >> S_SHIFT] EXT2_FT_SOCK,
253 [S_IFLNK >> S_SHIFT] EXT2_FT_SYMLINK,
256 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
258 mode_t mode = inode->i_mode;
259 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
263 new_obdfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
265 loff_t pos = filp->f_pos;
266 struct inode *inode = filp->f_dentry->d_inode;
267 // XXX struct super_block *sb = inode->i_sb;
268 unsigned offset = pos & ~PAGE_CACHE_MASK;
269 unsigned long n = pos >> PAGE_CACHE_SHIFT;
270 unsigned long npages = dir_pages(inode);
271 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
272 unsigned char *types = NULL;
273 int need_revalidate = (filp->f_version != inode->i_version);
275 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
278 types = ext2_filetype_table;
280 for ( ; n < npages; n++, offset = 0) {
283 struct page *page = ext2_get_page(inode, n);
287 kaddr = page_address(page);
288 if (need_revalidate) {
289 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
292 de = (ext2_dirent *)(kaddr+offset);
293 limit = kaddr + PAGE_CACHE_SIZE - EXT2_DIR_REC_LEN(1);
294 for ( ;(char*)de <= limit; de = ext2_next_entry(de))
297 unsigned char d_type = DT_UNKNOWN;
299 if (types && de->file_type < EXT2_FT_MAX)
300 d_type = types[de->file_type];
302 offset = (char *)de - kaddr;
303 over = filldir(dirent, de->name, de->name_len,
304 (n<<PAGE_CACHE_SHIFT) | offset,
305 le32_to_cpu(de->inode), d_type);
315 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
316 filp->f_version = inode->i_version;
324 * finds an entry in the specified directory with the wanted name. It
325 * returns the page in which the entry was found, and the entry itself
326 * (as a parameter - res_dir). Page is returned mapped and unlocked.
327 * Entry is guaranteed to be valid.
329 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
330 struct dentry *dentry, struct page ** res_page)
332 const char *name = dentry->d_name.name;
333 int namelen = dentry->d_name.len;
334 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
335 unsigned long start, n;
336 unsigned long npages = dir_pages(dir);
337 struct page *page = NULL;
343 // start = dir->u.ext2_i.i_dir_start_lookup;
350 page = ext2_get_page(dir, n);
352 kaddr = page_address(page);
353 de = (ext2_dirent *) kaddr;
354 kaddr += PAGE_CACHE_SIZE - reclen;
355 while ((char *) de <= kaddr) {
356 if (ext2_match (namelen, name, de))
358 de = ext2_next_entry(de);
364 } while (n != start);
369 // dir->u.ext2_i.i_dir_start_lookup = n;
373 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
375 struct page *page = ext2_get_page(dir, 0);
376 ext2_dirent *de = NULL;
379 de = ext2_next_entry((ext2_dirent *) page_address(page));
385 ino_t obdfs_inode_by_name(struct inode * dir, struct dentry *dentry, int *type)
388 struct ext2_dir_entry_2 * de;
391 de = ext2_find_entry (dir, dentry, &page);
393 res = le32_to_cpu(de->inode);
394 *type = obdfs_dt2fmt[de->file_type];
396 page_cache_release(page);
401 /* Releases the page */
402 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
403 struct page *page, struct inode *inode)
405 unsigned from = (char *) de - (char *) page_address(page);
406 unsigned to = from + le16_to_cpu(de->rec_len);
410 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
413 de->inode = cpu_to_le32(inode->i_ino);
414 ext2_set_de_type (de, inode);
415 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
416 err = ext2_commit_chunk(page, from, to);
424 int ext2_add_link (struct dentry *dentry, struct inode *inode)
426 struct inode *dir = dentry->d_parent->d_inode;
427 const char *name = dentry->d_name.name;
428 int namelen = dentry->d_name.len;
429 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
430 unsigned short rec_len, name_len;
431 struct page *page = NULL;
433 unsigned long npages = dir_pages(dir);
439 /* We take care of directory expansion in the same loop */
440 for (n = 0; n <= npages; n++) {
441 page = ext2_get_page(dir, n);
445 kaddr = page_address(page);
446 de = (ext2_dirent *)kaddr;
447 kaddr += PAGE_CACHE_SIZE - reclen;
448 while ((char *)de <= kaddr) {
450 if (ext2_match (namelen, name, de))
452 name_len = EXT2_DIR_REC_LEN(de->name_len);
453 rec_len = le16_to_cpu(de->rec_len);
454 if ( n==npages && rec_len == 0) {
455 CERROR("Fatal dir behaviour\n");
458 if (!de->inode && rec_len >= reclen)
460 if (rec_len >= name_len + reclen)
462 de = (ext2_dirent *) ((char *) de + rec_len);
470 from = (char*)de - (char*)page_address(page);
473 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
477 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
478 de1->rec_len = cpu_to_le16(rec_len - name_len);
479 de->rec_len = cpu_to_le16(name_len);
482 de->name_len = namelen;
483 memcpy (de->name, name, namelen);
484 de->inode = cpu_to_le32(inode->i_ino);
485 ext2_set_de_type (de, inode);
486 CDEBUG(D_INODE, "type set to %o\n", de->file_type);
487 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
488 err = ext2_commit_chunk(page, from, to);
490 // change_inode happens with the commit_chunk
491 // obdfs_change_inode(dir);
502 * ext2_delete_entry deletes a directory entry by merging it with the
503 * previous entry. Page is up-to-date. Releases the page.
505 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
507 struct address_space *mapping = page->mapping;
508 struct inode *inode = mapping->host;
509 char *kaddr = page_address(page);
510 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
511 unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
512 ext2_dirent * pde = NULL;
513 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
516 while ((char*)de < (char*)dir) {
518 de = ext2_next_entry(de);
521 from = (char*)pde - (char*)page_address(page);
523 err = mapping->a_ops->prepare_write(NULL, page, from, to);
527 pde->rec_len = cpu_to_le16(to-from);
529 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
530 err = ext2_commit_chunk(page, from, to);
537 * Set the first fragment of directory.
539 int ext2_make_empty(struct inode *inode, struct inode *parent)
541 struct address_space *mapping = inode->i_mapping;
542 struct page *page = grab_cache_page(mapping, 0);
543 unsigned chunk_size = ext2_chunk_size(inode);
544 struct ext2_dir_entry_2 * de;
551 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
555 base = page_address(page);
557 de = (struct ext2_dir_entry_2 *) base;
559 de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
560 memcpy (de->name, ".\0\0", 4);
561 de->inode = cpu_to_le32(inode->i_ino);
562 ext2_set_de_type (de, inode);
564 de = (struct ext2_dir_entry_2 *) (base + EXT2_DIR_REC_LEN(1));
566 de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
567 de->inode = cpu_to_le32(parent->i_ino);
568 memcpy (de->name, "..\0", 4);
569 ext2_set_de_type (de, inode);
571 err = ext2_commit_chunk(page, 0, chunk_size);
574 page_cache_release(page);
580 * routine to check that the specified directory is empty (for rmdir)
582 int ext2_empty_dir (struct inode * inode)
584 struct page *page = NULL;
585 unsigned long i, npages = dir_pages(inode);
587 for (i = 0; i < npages; i++) {
590 page = ext2_get_page(inode, i);
595 kaddr = page_address(page);
596 de = (ext2_dirent *)kaddr;
597 kaddr += PAGE_CACHE_SIZE-EXT2_DIR_REC_LEN(1);
599 while ((char *)de <= kaddr) {
600 if (de->inode != 0) {
601 /* check for . and .. */
602 if (de->name[0] != '.')
604 if (de->name_len > 2)
606 if (de->name_len < 2) {
608 cpu_to_le32(inode->i_ino))
610 } else if (de->name[1] != '.')
613 de = ext2_next_entry(de);
624 struct file_operations obdfs_dir_operations = {
625 read: generic_read_dir,
626 readdir: new_obdfs_readdir