4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * minix directory handling functions
10 #include <linux/minix_fs.h>
11 #include <linux/pagemap.h>
13 typedef struct minix_dir_entry minix_dirent;
15 static int minix_readdir(struct file *, void *, filldir_t);
17 struct file_operations minix_dir_operations = {
18 read: generic_read_dir,
19 readdir: minix_readdir,
20 fsync: minix_sync_file,
23 static inline void dir_put_page(struct page *page)
26 page_cache_release(page);
29 static inline unsigned long dir_pages(struct inode *inode)
31 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
34 static int dir_commit_chunk(struct page *page, unsigned from, unsigned to)
36 struct inode *dir = (struct inode *)page->mapping->host;
38 page->mapping->a_ops->commit_write(NULL, page, from, to);
41 err = writeout_one_page(page);
42 err2 = waitfor_one_page(page);
49 static struct page * dir_get_page(struct inode *dir, unsigned long n)
51 struct address_space *mapping = dir->i_mapping;
52 struct page *page = read_cache_page(mapping, n,
53 (filler_t*)mapping->a_ops->readpage, NULL);
57 if (!Page_Uptodate(page))
67 static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
69 return (void*)((char*)de + sbi->s_dirsize);
72 static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir)
74 unsigned long pos = filp->f_pos;
75 struct inode *inode = filp->f_dentry->d_inode;
76 struct super_block *sb = inode->i_sb;
77 unsigned offset = pos & ~PAGE_CACHE_MASK;
78 unsigned long n = pos >> PAGE_CACHE_SHIFT;
79 unsigned long npages = dir_pages(inode);
80 struct minix_sb_info *sbi = &sb->u.minix_sb;
81 unsigned chunk_size = sbi->s_dirsize;
83 pos = (pos + chunk_size-1) & ~(chunk_size-1);
84 if (pos >= inode->i_size)
87 for ( ; n < npages; n++, offset = 0) {
88 char *p, *kaddr, *limit;
89 struct page *page = dir_get_page(inode, n);
93 kaddr = (char *)page_address(page);
95 limit = kaddr + PAGE_CACHE_SIZE - chunk_size;
96 for ( ; p <= limit ; p = minix_next_entry(p, sbi)) {
97 minix_dirent *de = (minix_dirent *)p;
100 unsigned l = strnlen(de->name,sbi->s_namelen);
103 over = filldir(dirent, de->name, l,
104 (n<<PAGE_CACHE_SHIFT) | offset,
105 de->inode, DT_UNKNOWN);
116 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
121 static inline int namecompare(int len, int maxlen,
122 const char * name, const char * buffer)
124 if (len < maxlen && buffer[len])
126 return !memcmp(name, buffer, len);
132 * finds an entry in the specified directory with the wanted name. It
133 * returns the cache buffer in which the entry was found, and the entry
134 * itself (as a parameter - res_dir). It does NOT read the inode of the
135 * entry - you'll have to do that yourself if you want to.
137 minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
139 const char * name = dentry->d_name.name;
140 int namelen = dentry->d_name.len;
141 struct inode * dir = dentry->d_parent->d_inode;
142 struct super_block * sb = dir->i_sb;
143 struct minix_sb_info * sbi = &sb->u.minix_sb;
145 unsigned long npages = dir_pages(dir);
146 struct page *page = NULL;
147 struct minix_dir_entry *de;
151 for (n = 0; n < npages; n++) {
153 page = dir_get_page(dir, n);
157 kaddr = (char*)page_address(page);
158 de = (struct minix_dir_entry *) kaddr;
159 kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize;
160 for ( ; (char *) de <= kaddr ; de = minix_next_entry(de,sbi)) {
163 if (namecompare(namelen,sbi->s_namelen,name,de->name))
175 int minix_add_link(struct dentry *dentry, struct inode *inode)
177 struct inode *dir = dentry->d_parent->d_inode;
178 const char * name = dentry->d_name.name;
179 int namelen = dentry->d_name.len;
180 struct super_block * sb = dir->i_sb;
181 struct minix_sb_info * sbi = &sb->u.minix_sb;
182 struct page *page = NULL;
183 struct minix_dir_entry * de;
184 unsigned long npages = dir_pages(dir);
190 /* We take care of directory expansion in the same loop */
191 for (n = 0; n <= npages; n++) {
192 page = dir_get_page(dir, n);
196 kaddr = (char*)page_address(page);
197 de = (minix_dirent *)kaddr;
198 kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize;
199 while ((char *)de <= kaddr) {
203 if (namecompare(namelen,sbi->s_namelen,name,de->name))
205 de = minix_next_entry(de, sbi);
213 from = (char*)de - (char*)page_address(page);
214 to = from + sbi->s_dirsize;
216 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
219 memcpy (de->name, name, namelen);
220 memset (de->name + namelen, 0, sbi->s_dirsize - namelen - 2);
221 de->inode = inode->i_ino;
222 err = dir_commit_chunk(page, from, to);
223 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
224 mark_inode_dirty(dir);
233 int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
235 struct address_space *mapping = page->mapping;
236 struct inode *inode = (struct inode*)mapping->host;
237 char *kaddr = (char*)page_address(page);
238 unsigned from = (char*)de - kaddr;
239 unsigned to = from + inode->i_sb->u.minix_sb.s_dirsize;
243 err = mapping->a_ops->prepare_write(NULL, page, from, to);
246 err = dir_commit_chunk(page, from, to);
250 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
251 mark_inode_dirty(inode);
255 int minix_make_empty(struct inode *inode, struct inode *dir)
257 struct address_space *mapping = inode->i_mapping;
258 struct page *page = grab_cache_page(mapping, 0);
259 struct minix_sb_info * sbi = &inode->i_sb->u.minix_sb;
260 struct minix_dir_entry * de;
266 err = mapping->a_ops->prepare_write(NULL, page, 0, 2 * sbi->s_dirsize);
270 base = (char*)page_address(page);
271 memset(base, 0, PAGE_CACHE_SIZE);
273 de = (struct minix_dir_entry *) base;
274 de->inode = inode->i_ino;
275 strcpy(de->name,".");
276 de = minix_next_entry(de, sbi);
277 de->inode = dir->i_ino;
278 strcpy(de->name,"..");
280 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
283 page_cache_release(page);
288 * routine to check that the specified directory is empty (for rmdir)
290 int minix_empty_dir(struct inode * inode)
292 struct page *page = NULL;
293 unsigned long i, npages = dir_pages(inode);
294 struct minix_sb_info *sbi = &inode->i_sb->u.minix_sb;
296 for (i = 0; i < npages; i++) {
299 page = dir_get_page(inode, i);
304 kaddr = (char *)page_address(page);
305 de = (minix_dirent *)kaddr;
306 kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize;
308 while ((char *)de <= kaddr) {
309 if (de->inode != 0) {
310 /* check for . and .. */
311 if (de->name[0] != '.')
314 if (de->inode != inode->i_ino)
316 } else if (de->name[1] != '.')
318 else if (de->name[2])
321 de = minix_next_entry(de, sbi);
332 /* Releases the page */
333 void minix_set_link(struct minix_dir_entry *de, struct page *page,
336 struct inode *dir = (struct inode*)page->mapping->host;
337 struct minix_sb_info *sbi = &dir->i_sb->u.minix_sb;
338 unsigned from = (char *)de-(char*)page_address(page);
339 unsigned to = from + sbi->s_dirsize;
343 err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
345 de->inode = inode->i_ino;
346 err = dir_commit_chunk(page, from, to);
350 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
351 mark_inode_dirty(dir);
354 struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
356 struct page *page = dir_get_page(dir, 0);
357 struct minix_sb_info *sbi = &dir->i_sb->u.minix_sb;
358 struct minix_dir_entry *de = NULL;
361 de = minix_next_entry(page_address(page), sbi);
367 ino_t minix_inode_by_name(struct dentry *dentry)
370 struct minix_dir_entry *de = minix_find_entry(dentry, &page);