3 * Copyright (C) 1992, 1993, 1994, 1995
4 * Remy Card (card@masi.ibp.fr)
5 * Laboratoire MASI - Institut Blaise Pascal
6 * Universite Pierre et Marie Curie (Paris VI)
10 * 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
23 * Adapted for Lustre Light
24 * Copyright (C) 2002, Cluster File Systems, Inc.
29 #include <linux/ext2_fs.h>
30 #include <linux/pagemap.h>
32 #include <linux/obd_support.h>
33 #include <linux/locks.h>
35 typedef struct ext2_dir_entry_2 ext2_dirent;
37 #define PageChecked(page) test_bit(PG_checked, &(page)->flags)
38 #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
40 int waitfor_one_page(struct page *page)
43 struct buffer_head *bh, *head = page->buffers;
48 if (buffer_req(bh) && !buffer_uptodate(bh))
50 } while ((bh = bh->b_this_page) != head);
55 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
56 * more robust, but we have what we have
58 static inline unsigned ext2_chunk_size(struct inode *inode)
60 //return inode->i_sb->s_blocksize;
64 static inline void ext2_put_page(struct page *page)
67 page_cache_release(page);
70 static inline unsigned long dir_pages(struct inode *inode)
72 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
75 extern void set_page_clean(struct page *page);
77 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
79 struct inode *dir = page->mapping->host;
82 dir->i_version = ++event;
83 dir->i_size = (page->index << PAGE_CACHE_SHIFT) + to;
84 SetPageUptodate(page);
87 //page->mapping->a_ops->commit_write(NULL, page, from, to);
89 // err = waitfor_one_page(page);
93 static void ext2_check_page(struct page *page)
95 struct inode *dir = page->mapping->host;
96 unsigned chunk_size = ext2_chunk_size(dir);
97 char *kaddr = page_address(page);
98 // u32 max_inumber = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
99 unsigned offs, rec_len;
100 unsigned limit = PAGE_CACHE_SIZE;
104 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
105 limit = dir->i_size & ~PAGE_CACHE_MASK;
106 if (limit & (chunk_size - 1))
108 for (offs = limit; offs<PAGE_CACHE_SIZE; offs += chunk_size) {
109 ext2_dirent *p = (ext2_dirent*)(kaddr + offs);
110 p->rec_len = cpu_to_le16(chunk_size);
115 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
116 p = (ext2_dirent *)(kaddr + offs);
117 rec_len = le16_to_cpu(p->rec_len);
119 if (rec_len < EXT2_DIR_REC_LEN(1))
123 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
125 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
127 // if (le32_to_cpu(p->inode) > max_inumber)
133 SetPageChecked(page);
136 /* Too bad, we had an error */
139 printk("ext2_check_page"
140 "size of directory #%lu is not a multiple of chunk size",
145 error = "rec_len is smaller than minimal";
148 error = "unaligned directory entry";
151 error = "rec_len is too small for name_len";
154 error = "directory entry across blocks";
157 // error = "inode out of bounds";
159 printk("ext2_check_page: bad entry in directory #%lu: %s - "
160 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
161 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
162 (unsigned long) le32_to_cpu(p->inode),
163 rec_len, p->name_len);
166 p = (ext2_dirent *)(kaddr + offs);
167 printk("ext2_check_page"
168 "entry in directory #%lu spans the page boundary"
169 "offset=%lu, inode=%lu",
170 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
171 (unsigned long) le32_to_cpu(p->inode));
173 SetPageChecked(page);
177 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
179 struct address_space *mapping = dir->i_mapping;
180 struct page *page = read_cache_page(mapping, n,
181 (filler_t*)mapping->a_ops->readpage, NULL);
185 if (!Page_Uptodate(page))
187 if (!PageChecked(page))
188 ext2_check_page(page);
196 return ERR_PTR(-EIO);
200 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
202 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
204 static inline int ext2_match (int len, const char * const name,
205 struct ext2_dir_entry_2 * de)
207 if (len != de->name_len)
211 return !memcmp(name, de->name, len);
215 * p is at least 6 bytes before the end of page
217 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
219 return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
222 static inline unsigned
223 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
225 ext2_dirent *de = (ext2_dirent*)(base + offset);
226 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
227 while ((char*)p < (char*)de)
228 p = ext2_next_entry(p);
229 return (char *)p - base;
232 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
233 [EXT2_FT_UNKNOWN] DT_UNKNOWN,
234 [EXT2_FT_REG_FILE] DT_REG,
235 [EXT2_FT_DIR] DT_DIR,
236 [EXT2_FT_CHRDEV] DT_CHR,
237 [EXT2_FT_BLKDEV] DT_BLK,
238 [EXT2_FT_FIFO] DT_FIFO,
239 [EXT2_FT_SOCK] DT_SOCK,
240 [EXT2_FT_SYMLINK] DT_LNK,
243 static unsigned int ll_dt2fmt[DT_WHT + 1] = {
245 [EXT2_FT_REG_FILE] S_IFREG,
246 [EXT2_FT_DIR] S_IFDIR,
247 [EXT2_FT_CHRDEV] S_IFCHR,
248 [EXT2_FT_BLKDEV] S_IFBLK,
249 [EXT2_FT_FIFO] S_IFIFO,
250 [EXT2_FT_SOCK] S_IFSOCK,
251 [EXT2_FT_SYMLINK] S_IFLNK
255 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
256 [S_IFREG >> S_SHIFT] EXT2_FT_REG_FILE,
257 [S_IFDIR >> S_SHIFT] EXT2_FT_DIR,
258 [S_IFCHR >> S_SHIFT] EXT2_FT_CHRDEV,
259 [S_IFBLK >> S_SHIFT] EXT2_FT_BLKDEV,
260 [S_IFIFO >> S_SHIFT] EXT2_FT_FIFO,
261 [S_IFSOCK >> S_SHIFT] EXT2_FT_SOCK,
262 [S_IFLNK >> S_SHIFT] EXT2_FT_SYMLINK,
265 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
267 mode_t mode = inode->i_mode;
268 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
272 new_ll_readdir (struct file * filp, void * dirent, filldir_t filldir)
274 loff_t pos = filp->f_pos;
275 struct inode *inode = filp->f_dentry->d_inode;
276 // XXX struct super_block *sb = inode->i_sb;
277 unsigned offset = pos & ~PAGE_CACHE_MASK;
278 unsigned long n = pos >> PAGE_CACHE_SHIFT;
279 unsigned long npages = dir_pages(inode);
280 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
281 unsigned char *types = NULL;
282 int need_revalidate = (filp->f_version != inode->i_version);
284 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
287 types = ext2_filetype_table;
289 for ( ; n < npages; n++, offset = 0) {
292 struct page *page = ext2_get_page(inode, n);
296 kaddr = page_address(page);
297 if (need_revalidate) {
298 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
301 de = (ext2_dirent *)(kaddr+offset);
302 limit = kaddr + PAGE_CACHE_SIZE - EXT2_DIR_REC_LEN(1);
303 for ( ;(char*)de <= limit; de = ext2_next_entry(de))
306 unsigned char d_type = DT_UNKNOWN;
308 if (types && de->file_type < EXT2_FT_MAX)
309 d_type = types[de->file_type];
311 offset = (char *)de - kaddr;
312 over = filldir(dirent, de->name, de->name_len,
313 (n<<PAGE_CACHE_SHIFT) | offset,
314 le32_to_cpu(de->inode), d_type);
324 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
325 filp->f_version = inode->i_version;
333 * finds an entry in the specified directory with the wanted name. It
334 * returns the page in which the entry was found, and the entry itself
335 * (as a parameter - res_dir). Page is returned mapped and unlocked.
336 * Entry is guaranteed to be valid.
338 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
339 struct dentry *dentry, struct page ** res_page)
341 const char *name = dentry->d_name.name;
342 int namelen = dentry->d_name.len;
343 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
344 unsigned long start, n;
345 unsigned long npages = dir_pages(dir);
346 struct page *page = NULL;
352 // start = dir->u.ext2_i.i_dir_start_lookup;
359 page = ext2_get_page(dir, n);
361 kaddr = page_address(page);
362 de = (ext2_dirent *) kaddr;
363 kaddr += PAGE_CACHE_SIZE - reclen;
364 while ((char *) de <= kaddr) {
365 if (ext2_match (namelen, name, de))
367 de = ext2_next_entry(de);
373 } while (n != start);
378 // dir->u.ext2_i.i_dir_start_lookup = n;
382 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
384 struct page *page = ext2_get_page(dir, 0);
385 ext2_dirent *de = NULL;
388 de = ext2_next_entry((ext2_dirent *) page_address(page));
394 ino_t ll_inode_by_name(struct inode * dir, struct dentry *dentry, int *type)
397 struct ext2_dir_entry_2 * de;
400 de = ext2_find_entry (dir, dentry, &page);
402 res = le32_to_cpu(de->inode);
403 *type = ll_dt2fmt[de->file_type];
405 page_cache_release(page);
410 /* Releases the page */
411 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
412 struct page *page, struct inode *inode)
414 unsigned from = (char *) de - (char *) page_address(page);
415 unsigned to = from + le16_to_cpu(de->rec_len);
419 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
422 de->inode = cpu_to_le32(inode->i_ino);
423 ext2_set_de_type (de, inode);
424 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
425 err = ext2_commit_chunk(page, from, to);
433 int ll_add_link (struct dentry *dentry, struct inode *inode)
435 struct inode *dir = dentry->d_parent->d_inode;
436 const char *name = dentry->d_name.name;
437 int namelen = dentry->d_name.len;
438 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
439 unsigned short rec_len, name_len;
440 struct page *page = NULL;
442 unsigned long npages = dir_pages(dir);
448 /* We take care of directory expansion in the same loop */
449 for (n = 0; n <= npages; n++) {
450 page = ext2_get_page(dir, n);
454 kaddr = page_address(page);
455 de = (ext2_dirent *)kaddr;
456 kaddr += PAGE_CACHE_SIZE - reclen;
457 while ((char *)de <= kaddr) {
459 if (ext2_match (namelen, name, de))
461 name_len = EXT2_DIR_REC_LEN(de->name_len);
462 rec_len = le16_to_cpu(de->rec_len);
463 if ( n==npages && rec_len == 0) {
464 printk("Fatal dir behaviour\n");
467 if (!de->inode && rec_len >= reclen)
469 if (rec_len >= name_len + reclen)
471 de = (ext2_dirent *) ((char *) de + rec_len);
479 from = (char*)de - (char*)page_address(page);
482 //err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
486 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
487 de1->rec_len = cpu_to_le16(rec_len - name_len);
488 de->rec_len = cpu_to_le16(name_len);
491 de->name_len = namelen;
492 memcpy (de->name, name, namelen);
493 de->inode = cpu_to_le32(inode->i_ino);
494 ext2_set_de_type (de, inode);
495 CDEBUG(D_INODE, "type set to %o\n", de->file_type);
496 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
497 err = ext2_commit_chunk(page, from, to);
499 // change_inode happens with the commit_chunk
500 /* XXX OFFSET_CACHE */
511 * ext2_delete_entry deletes a directory entry by merging it with the
512 * previous entry. Page is up-to-date. Releases the page.
514 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
516 struct address_space *mapping = page->mapping;
517 struct inode *inode = mapping->host;
518 char *kaddr = page_address(page);
519 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
520 unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
521 ext2_dirent * pde = NULL;
522 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
525 while ((char*)de < (char*)dir) {
527 de = ext2_next_entry(de);
530 from = (char*)pde - (char*)page_address(page);
532 err = mapping->a_ops->prepare_write(NULL, page, from, to);
536 pde->rec_len = cpu_to_le16(to-from);
538 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
539 err = ext2_commit_chunk(page, from, to);
546 * Set the first fragment of directory.
548 int ext2_make_empty(struct inode *inode, struct inode *parent)
550 struct address_space *mapping = inode->i_mapping;
551 struct page *page = grab_cache_page(mapping, 0);
552 unsigned chunk_size = ext2_chunk_size(inode);
553 struct ext2_dir_entry_2 * de;
560 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
564 base = page_address(page);
566 de = (struct ext2_dir_entry_2 *) base;
568 de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
569 memcpy (de->name, ".\0\0", 4);
570 de->inode = cpu_to_le32(inode->i_ino);
571 ext2_set_de_type (de, inode);
573 de = (struct ext2_dir_entry_2 *) (base + EXT2_DIR_REC_LEN(1));
575 de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
576 de->inode = cpu_to_le32(parent->i_ino);
577 memcpy (de->name, "..\0", 4);
578 ext2_set_de_type (de, inode);
580 err = ext2_commit_chunk(page, 0, chunk_size);
583 page_cache_release(page);
589 * routine to check that the specified directory is empty (for rmdir)
591 int ext2_empty_dir (struct inode * inode)
593 struct page *page = NULL;
594 unsigned long i, npages = dir_pages(inode);
596 for (i = 0; i < npages; i++) {
599 page = ext2_get_page(inode, i);
604 kaddr = page_address(page);
605 de = (ext2_dirent *)kaddr;
606 kaddr += PAGE_CACHE_SIZE-EXT2_DIR_REC_LEN(1);
608 while ((char *)de <= kaddr) {
609 if (de->inode != 0) {
610 /* check for . and .. */
611 if (de->name[0] != '.')
613 if (de->name_len > 2)
615 if (de->name_len < 2) {
617 cpu_to_le32(inode->i_ino))
619 } else if (de->name[1] != '.')
622 de = ext2_next_entry(de);
633 struct file_operations ll_dir_operations = {
634 read: generic_read_dir,
635 readdir: new_ll_readdir