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)
35 int waitfor_one_page(struct page *page)
38 struct buffer_head *bh, *head = page->buffers;
43 if (buffer_req(bh) && !buffer_uptodate(bh))
45 } while ((bh = bh->b_this_page) != head);
50 * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
51 * more robust, but we have what we have
53 static inline unsigned ext2_chunk_size(struct inode *inode)
55 //return inode->i_sb->s_blocksize;
59 static inline void ext2_put_page(struct page *page)
62 page_cache_release(page);
65 static inline unsigned long dir_pages(struct inode *inode)
67 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
70 static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
72 struct inode *dir = page->mapping->host;
74 dir->i_version = ++event;
75 page->mapping->a_ops->commit_write(NULL, page, from, to);
77 err = waitfor_one_page(page);
81 static void ext2_check_page(struct page *page)
83 struct inode *dir = page->mapping->host;
84 struct super_block *sb = dir->i_sb;
85 unsigned chunk_size = ext2_chunk_size(dir);
86 char *kaddr = page_address(page);
87 // u32 max_inumber = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
88 unsigned offs, rec_len;
89 unsigned limit = PAGE_CACHE_SIZE;
93 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
94 limit = dir->i_size & ~PAGE_CACHE_MASK;
95 if (limit & (chunk_size - 1))
97 for (offs = limit; offs<PAGE_CACHE_SIZE; offs += chunk_size) {
98 ext2_dirent *p = (ext2_dirent*)(kaddr + offs);
99 p->rec_len = cpu_to_le16(chunk_size);
104 for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
105 p = (ext2_dirent *)(kaddr + offs);
106 rec_len = le16_to_cpu(p->rec_len);
108 if (rec_len < EXT2_DIR_REC_LEN(1))
112 if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
114 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
116 // if (le32_to_cpu(p->inode) > max_inumber)
122 SetPageChecked(page);
125 /* Too bad, we had an error */
128 ext2_error(sb, "ext2_check_page",
129 "size of directory #%lu is not a multiple of chunk size",
134 error = "rec_len is smaller than minimal";
137 error = "unaligned directory entry";
140 error = "rec_len is too small for name_len";
143 error = "directory entry across blocks";
146 // error = "inode out of bounds";
148 ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - "
149 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
150 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
151 (unsigned long) le32_to_cpu(p->inode),
152 rec_len, p->name_len);
155 p = (ext2_dirent *)(kaddr + offs);
156 ext2_error (sb, "ext2_check_page",
157 "entry in directory #%lu spans the page boundary"
158 "offset=%lu, inode=%lu",
159 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
160 (unsigned long) le32_to_cpu(p->inode));
162 SetPageChecked(page);
166 static struct page * ext2_get_page(struct inode *dir, unsigned long n)
168 struct address_space *mapping = dir->i_mapping;
169 struct page *page = read_cache_page(mapping, n,
170 (filler_t*)mapping->a_ops->readpage, NULL);
174 if (!Page_Uptodate(page))
176 if (!PageChecked(page))
177 ext2_check_page(page);
185 return ERR_PTR(-EIO);
189 * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
191 * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
193 static inline int ext2_match (int len, const char * const name,
194 struct ext2_dir_entry_2 * de)
196 if (len != de->name_len)
200 return !memcmp(name, de->name, len);
204 * p is at least 6 bytes before the end of page
206 static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
208 return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
211 static inline unsigned
212 ext2_validate_entry(char *base, unsigned offset, unsigned mask)
214 ext2_dirent *de = (ext2_dirent*)(base + offset);
215 ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
216 while ((char*)p < (char*)de)
217 p = ext2_next_entry(p);
218 return (char *)p - base;
221 static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
222 [EXT2_FT_UNKNOWN] DT_UNKNOWN,
223 [EXT2_FT_REG_FILE] DT_REG,
224 [EXT2_FT_DIR] DT_DIR,
225 [EXT2_FT_CHRDEV] DT_CHR,
226 [EXT2_FT_BLKDEV] DT_BLK,
227 [EXT2_FT_FIFO] DT_FIFO,
228 [EXT2_FT_SOCK] DT_SOCK,
229 [EXT2_FT_SYMLINK] DT_LNK,
232 static unsigned int obdfs_dt2fmt[DT_WHT + 1] = {
234 [EXT2_FT_REG_FILE] S_IFREG,
235 [EXT2_FT_DIR] S_IFDIR,
236 [EXT2_FT_CHRDEV] S_IFCHR,
237 [EXT2_FT_BLKDEV] S_IFBLK,
238 [EXT2_FT_FIFO] S_IFIFO,
239 [EXT2_FT_SOCK] S_IFSOCK,
240 [EXT2_FT_SYMLINK] S_IFLNK
244 static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
245 [S_IFREG >> S_SHIFT] EXT2_FT_REG_FILE,
246 [S_IFDIR >> S_SHIFT] EXT2_FT_DIR,
247 [S_IFCHR >> S_SHIFT] EXT2_FT_CHRDEV,
248 [S_IFBLK >> S_SHIFT] EXT2_FT_BLKDEV,
249 [S_IFIFO >> S_SHIFT] EXT2_FT_FIFO,
250 [S_IFSOCK >> S_SHIFT] EXT2_FT_SOCK,
251 [S_IFLNK >> S_SHIFT] EXT2_FT_SYMLINK,
254 static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
256 mode_t mode = inode->i_mode;
257 de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
261 new_obdfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
263 loff_t pos = filp->f_pos;
264 struct inode *inode = filp->f_dentry->d_inode;
265 // XXX struct super_block *sb = inode->i_sb;
266 unsigned offset = pos & ~PAGE_CACHE_MASK;
267 unsigned long n = pos >> PAGE_CACHE_SHIFT;
268 unsigned long npages = dir_pages(inode);
269 unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
270 unsigned char *types = NULL;
271 int need_revalidate = (filp->f_version != inode->i_version);
273 if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
276 types = ext2_filetype_table;
278 for ( ; n < npages; n++, offset = 0) {
281 struct page *page = ext2_get_page(inode, n);
285 kaddr = page_address(page);
286 if (need_revalidate) {
287 offset = ext2_validate_entry(kaddr, offset, chunk_mask);
290 de = (ext2_dirent *)(kaddr+offset);
291 limit = kaddr + PAGE_CACHE_SIZE - EXT2_DIR_REC_LEN(1);
292 for ( ;(char*)de <= limit; de = ext2_next_entry(de))
295 unsigned char d_type = DT_UNKNOWN;
297 if (types && de->file_type < EXT2_FT_MAX)
298 d_type = types[de->file_type];
300 offset = (char *)de - kaddr;
301 over = filldir(dirent, de->name, de->name_len,
302 (n<<PAGE_CACHE_SHIFT) | offset,
303 le32_to_cpu(de->inode), d_type);
313 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
314 filp->f_version = inode->i_version;
322 * finds an entry in the specified directory with the wanted name. It
323 * returns the page in which the entry was found, and the entry itself
324 * (as a parameter - res_dir). Page is returned mapped and unlocked.
325 * Entry is guaranteed to be valid.
327 struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
328 struct dentry *dentry, struct page ** res_page)
330 const char *name = dentry->d_name.name;
331 int namelen = dentry->d_name.len;
332 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
333 unsigned long start, n;
334 unsigned long npages = dir_pages(dir);
335 struct page *page = NULL;
341 // start = dir->u.ext2_i.i_dir_start_lookup;
348 page = ext2_get_page(dir, n);
350 kaddr = page_address(page);
351 de = (ext2_dirent *) kaddr;
352 kaddr += PAGE_CACHE_SIZE - reclen;
353 while ((char *) de <= kaddr) {
354 if (ext2_match (namelen, name, de))
356 de = ext2_next_entry(de);
362 } while (n != start);
367 // dir->u.ext2_i.i_dir_start_lookup = n;
371 struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
373 struct page *page = ext2_get_page(dir, 0);
374 ext2_dirent *de = NULL;
377 de = ext2_next_entry((ext2_dirent *) page_address(page));
383 ino_t obdfs_inode_by_name(struct inode * dir, struct dentry *dentry, int *type)
386 struct ext2_dir_entry_2 * de;
389 de = ext2_find_entry (dir, dentry, &page);
391 res = le32_to_cpu(de->inode);
392 *type = obdfs_dt2fmt[de->file_type];
394 page_cache_release(page);
399 /* Releases the page */
400 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
401 struct page *page, struct inode *inode)
403 unsigned from = (char *) de - (char *) page_address(page);
404 unsigned to = from + le16_to_cpu(de->rec_len);
408 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
411 de->inode = cpu_to_le32(inode->i_ino);
412 ext2_set_de_type (de, inode);
413 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
414 err = ext2_commit_chunk(page, from, to);
422 int ext2_add_link (struct dentry *dentry, struct inode *inode)
424 struct inode *dir = dentry->d_parent->d_inode;
425 const char *name = dentry->d_name.name;
426 int namelen = dentry->d_name.len;
427 unsigned reclen = EXT2_DIR_REC_LEN(namelen);
428 unsigned short rec_len, name_len;
429 struct page *page = NULL;
431 unsigned long npages = dir_pages(dir);
437 /* We take care of directory expansion in the same loop */
438 for (n = 0; n <= npages; n++) {
439 page = ext2_get_page(dir, n);
443 kaddr = page_address(page);
444 de = (ext2_dirent *)kaddr;
445 kaddr += PAGE_CACHE_SIZE - reclen;
446 while ((char *)de <= kaddr) {
448 if (ext2_match (namelen, name, de))
450 name_len = EXT2_DIR_REC_LEN(de->name_len);
451 rec_len = le16_to_cpu(de->rec_len);
452 if ( n==npages && rec_len == 0) {
453 printk("Fatal dir behaviour\n");
456 if (!de->inode && rec_len >= reclen)
458 if (rec_len >= name_len + reclen)
460 de = (ext2_dirent *) ((char *) de + rec_len);
468 from = (char*)de - (char*)page_address(page);
471 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
475 ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
476 de1->rec_len = cpu_to_le16(rec_len - name_len);
477 de->rec_len = cpu_to_le16(name_len);
480 de->name_len = namelen;
481 memcpy (de->name, name, namelen);
482 de->inode = cpu_to_le32(inode->i_ino);
483 ext2_set_de_type (de, inode);
484 CDEBUG(D_INODE, "type set to %o\n", de->file_type);
485 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
486 err = ext2_commit_chunk(page, from, to);
488 // change_inode happens with the commit_chunk
489 // obdfs_change_inode(dir);
500 * ext2_delete_entry deletes a directory entry by merging it with the
501 * previous entry. Page is up-to-date. Releases the page.
503 int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
505 struct address_space *mapping = page->mapping;
506 struct inode *inode = mapping->host;
507 char *kaddr = page_address(page);
508 unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
509 unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
510 ext2_dirent * pde = NULL;
511 ext2_dirent * de = (ext2_dirent *) (kaddr + from);
514 while ((char*)de < (char*)dir) {
516 de = ext2_next_entry(de);
519 from = (char*)pde - (char*)page_address(page);
521 err = mapping->a_ops->prepare_write(NULL, page, from, to);
525 pde->rec_len = cpu_to_le16(to-from);
527 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
528 err = ext2_commit_chunk(page, from, to);
535 * Set the first fragment of directory.
537 int ext2_make_empty(struct inode *inode, struct inode *parent)
539 struct address_space *mapping = inode->i_mapping;
540 struct page *page = grab_cache_page(mapping, 0);
541 unsigned chunk_size = ext2_chunk_size(inode);
542 struct ext2_dir_entry_2 * de;
549 err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
553 base = page_address(page);
555 de = (struct ext2_dir_entry_2 *) base;
557 de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
558 memcpy (de->name, ".\0\0", 4);
559 de->inode = cpu_to_le32(inode->i_ino);
560 ext2_set_de_type (de, inode);
562 de = (struct ext2_dir_entry_2 *) (base + EXT2_DIR_REC_LEN(1));
564 de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
565 de->inode = cpu_to_le32(parent->i_ino);
566 memcpy (de->name, "..\0", 4);
567 ext2_set_de_type (de, inode);
569 err = ext2_commit_chunk(page, 0, chunk_size);
572 page_cache_release(page);
578 * routine to check that the specified directory is empty (for rmdir)
580 int ext2_empty_dir (struct inode * inode)
582 struct page *page = NULL;
583 unsigned long i, npages = dir_pages(inode);
585 for (i = 0; i < npages; i++) {
588 page = ext2_get_page(inode, i);
593 kaddr = page_address(page);
594 de = (ext2_dirent *)kaddr;
595 kaddr += PAGE_CACHE_SIZE-EXT2_DIR_REC_LEN(1);
597 while ((char *)de <= kaddr) {
598 if (de->inode != 0) {
599 /* check for . and .. */
600 if (de->name[0] != '.')
602 if (de->name_len > 2)
604 if (de->name_len < 2) {
606 cpu_to_le32(inode->i_ino))
608 } else if (de->name[1] != '.')
611 de = ext2_next_entry(de);
622 struct file_operations obdfs_dir_operations = {
623 read: generic_read_dir,
624 readdir: new_obdfs_readdir