blob: dfaf6fa9b7b52a28bcb00ce3c4cd3df817158814 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/minix/dir.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * minix directory handling functions
Andries Brouwer939b00d2007-02-12 00:52:49 -08007 *
8 * Updated to filesystem version 3 by Daniel Aragones
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 */
10
11#include "minix.h"
Nick Piggin4a66af92007-10-16 01:25:21 -070012#include <linux/buffer_head.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/highmem.h>
Nick Piggin4a66af92007-10-16 01:25:21 -070014#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16typedef struct minix_dir_entry minix_dirent;
Andries Brouwer939b00d2007-02-12 00:52:49 -080017typedef struct minix3_dir_entry minix3_dirent;
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Al Viro80886292013-05-15 18:51:49 -040019static int minix_readdir(struct file *, struct dir_context *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080021const struct file_operations minix_dir_operations = {
Al Virocc467592009-06-16 23:47:45 -040022 .llseek = generic_file_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 .read = generic_read_dir,
Al Viro80886292013-05-15 18:51:49 -040024 .iterate = minix_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +020025 .fsync = generic_file_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -070026};
27
28static inline void dir_put_page(struct page *page)
29{
30 kunmap(page);
31 page_cache_release(page);
32}
33
34/*
35 * Return the offset into page `page_nr' of the last valid
36 * byte in that page, plus one.
37 */
38static unsigned
39minix_last_byte(struct inode *inode, unsigned long page_nr)
40{
41 unsigned last_byte = PAGE_CACHE_SIZE;
42
43 if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT))
44 last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1);
45 return last_byte;
46}
47
48static inline unsigned long dir_pages(struct inode *inode)
49{
50 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
51}
52
Nick Piggin4a66af92007-10-16 01:25:21 -070053static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070054{
Nick Piggin4a66af92007-10-16 01:25:21 -070055 struct address_space *mapping = page->mapping;
56 struct inode *dir = mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 int err = 0;
Nick Piggin4a66af92007-10-16 01:25:21 -070058 block_write_end(NULL, mapping, pos, len, len, page, NULL);
59
60 if (pos+len > dir->i_size) {
61 i_size_write(dir, pos+len);
62 mark_inode_dirty(dir);
63 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 if (IS_DIRSYNC(dir))
65 err = write_one_page(page, 1);
66 else
67 unlock_page(page);
68 return err;
69}
70
71static struct page * dir_get_page(struct inode *dir, unsigned long n)
72{
73 struct address_space *mapping = dir->i_mapping;
Pekka Enberg090d2b12006-06-23 02:05:08 -070074 struct page *page = read_mapping_page(mapping, n, NULL);
Al Viro49837a82010-05-28 11:34:50 -040075 if (!IS_ERR(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 kmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078}
79
80static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
81{
82 return (void*)((char*)de + sbi->s_dirsize);
83}
84
Al Viro80886292013-05-15 18:51:49 -040085static int minix_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086{
Al Viro80886292013-05-15 18:51:49 -040087 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 struct super_block *sb = inode->i_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 struct minix_sb_info *sbi = minix_sb(sb);
90 unsigned chunk_size = sbi->s_dirsize;
Al Viro80886292013-05-15 18:51:49 -040091 unsigned long npages = dir_pages(inode);
92 unsigned long pos = ctx->pos;
93 unsigned offset;
94 unsigned long n;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
Dan Carpenter642b7042013-06-19 10:08:10 +100096 ctx->pos = pos = ALIGN(pos, chunk_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 if (pos >= inode->i_size)
Al Viro80886292013-05-15 18:51:49 -040098 return 0;
99
100 offset = pos & ~PAGE_CACHE_MASK;
101 n = pos >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
103 for ( ; n < npages; n++, offset = 0) {
104 char *p, *kaddr, *limit;
105 struct page *page = dir_get_page(inode, n);
106
107 if (IS_ERR(page))
108 continue;
109 kaddr = (char *)page_address(page);
110 p = kaddr+offset;
111 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800112 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
Al Viro80886292013-05-15 18:51:49 -0400113 const char *name;
114 __u32 inumber;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800115 if (sbi->s_version == MINIX_V3) {
116 minix3_dirent *de3 = (minix3_dirent *)p;
117 name = de3->name;
118 inumber = de3->inode;
119 } else {
120 minix_dirent *de = (minix_dirent *)p;
121 name = de->name;
122 inumber = de->inode;
123 }
124 if (inumber) {
Andries Brouwer939b00d2007-02-12 00:52:49 -0800125 unsigned l = strnlen(name, sbi->s_namelen);
Al Viro80886292013-05-15 18:51:49 -0400126 if (!dir_emit(ctx, name, l,
127 inumber, DT_UNKNOWN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 dir_put_page(page);
Al Viro80886292013-05-15 18:51:49 -0400129 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 }
131 }
Al Viro80886292013-05-15 18:51:49 -0400132 ctx->pos += chunk_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134 dir_put_page(page);
135 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 return 0;
137}
138
139static inline int namecompare(int len, int maxlen,
140 const char * name, const char * buffer)
141{
142 if (len < maxlen && buffer[len])
143 return 0;
144 return !memcmp(name, buffer, len);
145}
146
147/*
148 * minix_find_entry()
149 *
150 * finds an entry in the specified directory with the wanted name. It
151 * returns the cache buffer in which the entry was found, and the entry
152 * itself (as a parameter - res_dir). It does NOT read the inode of the
153 * entry - you'll have to do that yourself if you want to.
154 */
155minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
156{
157 const char * name = dentry->d_name.name;
158 int namelen = dentry->d_name.len;
159 struct inode * dir = dentry->d_parent->d_inode;
160 struct super_block * sb = dir->i_sb;
161 struct minix_sb_info * sbi = minix_sb(sb);
162 unsigned long n;
163 unsigned long npages = dir_pages(dir);
164 struct page *page = NULL;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800165 char *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166
Andries Brouwer939b00d2007-02-12 00:52:49 -0800167 char *namx;
168 __u32 inumber;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 *res_page = NULL;
170
171 for (n = 0; n < npages; n++) {
Andries Brouwer939b00d2007-02-12 00:52:49 -0800172 char *kaddr, *limit;
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 page = dir_get_page(dir, n);
175 if (IS_ERR(page))
176 continue;
177
178 kaddr = (char*)page_address(page);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800179 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
180 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
181 if (sbi->s_version == MINIX_V3) {
182 minix3_dirent *de3 = (minix3_dirent *)p;
183 namx = de3->name;
184 inumber = de3->inode;
185 } else {
186 minix_dirent *de = (minix_dirent *)p;
187 namx = de->name;
188 inumber = de->inode;
189 }
190 if (!inumber)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 continue;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800192 if (namecompare(namelen, sbi->s_namelen, name, namx))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 goto found;
194 }
195 dir_put_page(page);
196 }
197 return NULL;
198
199found:
200 *res_page = page;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800201 return (minix_dirent *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202}
203
204int minix_add_link(struct dentry *dentry, struct inode *inode)
205{
206 struct inode *dir = dentry->d_parent->d_inode;
207 const char * name = dentry->d_name.name;
208 int namelen = dentry->d_name.len;
209 struct super_block * sb = dir->i_sb;
210 struct minix_sb_info * sbi = minix_sb(sb);
211 struct page *page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 unsigned long npages = dir_pages(dir);
213 unsigned long n;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800214 char *kaddr, *p;
215 minix_dirent *de;
216 minix3_dirent *de3;
Nick Piggin4a66af92007-10-16 01:25:21 -0700217 loff_t pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 int err;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800219 char *namx = NULL;
220 __u32 inumber;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
222 /*
223 * We take care of directory expansion in the same loop
224 * This code plays outside i_size, so it locks the page
225 * to protect that region.
226 */
227 for (n = 0; n <= npages; n++) {
Andries Brouwer939b00d2007-02-12 00:52:49 -0800228 char *limit, *dir_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230 page = dir_get_page(dir, n);
231 err = PTR_ERR(page);
232 if (IS_ERR(page))
233 goto out;
234 lock_page(page);
235 kaddr = (char*)page_address(page);
236 dir_end = kaddr + minix_last_byte(dir, n);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800237 limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
238 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
239 de = (minix_dirent *)p;
240 de3 = (minix3_dirent *)p;
241 if (sbi->s_version == MINIX_V3) {
242 namx = de3->name;
243 inumber = de3->inode;
244 } else {
245 namx = de->name;
246 inumber = de->inode;
247 }
248 if (p == dir_end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 /* We hit i_size */
Andries Brouwer939b00d2007-02-12 00:52:49 -0800250 if (sbi->s_version == MINIX_V3)
251 de3->inode = 0;
252 else
253 de->inode = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 goto got_it;
255 }
Andries Brouwer939b00d2007-02-12 00:52:49 -0800256 if (!inumber)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 goto got_it;
258 err = -EEXIST;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800259 if (namecompare(namelen, sbi->s_namelen, name, namx))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 }
262 unlock_page(page);
263 dir_put_page(page);
264 }
265 BUG();
266 return -EINVAL;
267
268got_it:
Evgeniy Dushistovd6b54842009-01-06 14:42:38 -0800269 pos = page_offset(page) + p - (char *)page_address(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200270 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 if (err)
272 goto out_unlock;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800273 memcpy (namx, name, namelen);
274 if (sbi->s_version == MINIX_V3) {
275 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
276 de3->inode = inode->i_ino;
277 } else {
278 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
279 de->inode = inode->i_ino;
280 }
Nick Piggin4a66af92007-10-16 01:25:21 -0700281 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
283 mark_inode_dirty(dir);
284out_put:
285 dir_put_page(page);
286out:
287 return err;
288out_unlock:
289 unlock_page(page);
290 goto out_put;
291}
292
293int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
294{
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200295 struct inode *inode = page->mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 char *kaddr = page_address(page);
Nick Piggin4a66af92007-10-16 01:25:21 -0700297 loff_t pos = page_offset(page) + (char*)de - kaddr;
Doug Graham9f6c1332009-09-22 16:48:00 -0700298 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
299 unsigned len = sbi->s_dirsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 int err;
301
302 lock_page(page);
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200303 err = minix_prepare_chunk(page, pos, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 if (err == 0) {
Doug Graham9f6c1332009-09-22 16:48:00 -0700305 if (sbi->s_version == MINIX_V3)
306 ((minix3_dirent *) de)->inode = 0;
307 else
308 de->inode = 0;
Nick Piggin4a66af92007-10-16 01:25:21 -0700309 err = dir_commit_chunk(page, pos, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 } else {
311 unlock_page(page);
312 }
313 dir_put_page(page);
314 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
315 mark_inode_dirty(inode);
316 return err;
317}
318
319int minix_make_empty(struct inode *inode, struct inode *dir)
320{
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200321 struct page *page = grab_cache_page(inode->i_mapping, 0);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800322 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 char *kaddr;
324 int err;
325
326 if (!page)
327 return -ENOMEM;
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200328 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 if (err) {
330 unlock_page(page);
331 goto fail;
332 }
333
Cong Wang27a6d5c2011-11-25 23:14:32 +0800334 kaddr = kmap_atomic(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 memset(kaddr, 0, PAGE_CACHE_SIZE);
336
Andries Brouwer939b00d2007-02-12 00:52:49 -0800337 if (sbi->s_version == MINIX_V3) {
338 minix3_dirent *de3 = (minix3_dirent *)kaddr;
339
340 de3->inode = inode->i_ino;
341 strcpy(de3->name, ".");
342 de3 = minix_next_entry(de3, sbi);
343 de3->inode = dir->i_ino;
344 strcpy(de3->name, "..");
345 } else {
346 minix_dirent *de = (minix_dirent *)kaddr;
347
348 de->inode = inode->i_ino;
349 strcpy(de->name, ".");
350 de = minix_next_entry(de, sbi);
351 de->inode = dir->i_ino;
352 strcpy(de->name, "..");
353 }
Cong Wang27a6d5c2011-11-25 23:14:32 +0800354 kunmap_atomic(kaddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355
356 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
357fail:
358 page_cache_release(page);
359 return err;
360}
361
362/*
363 * routine to check that the specified directory is empty (for rmdir)
364 */
365int minix_empty_dir(struct inode * inode)
366{
367 struct page *page = NULL;
368 unsigned long i, npages = dir_pages(inode);
369 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800370 char *name;
371 __u32 inumber;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
373 for (i = 0; i < npages; i++) {
Andries Brouwer939b00d2007-02-12 00:52:49 -0800374 char *p, *kaddr, *limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375
Andries Brouwer939b00d2007-02-12 00:52:49 -0800376 page = dir_get_page(inode, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 if (IS_ERR(page))
378 continue;
379
380 kaddr = (char *)page_address(page);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800381 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
382 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
383 if (sbi->s_version == MINIX_V3) {
384 minix3_dirent *de3 = (minix3_dirent *)p;
385 name = de3->name;
386 inumber = de3->inode;
387 } else {
388 minix_dirent *de = (minix_dirent *)p;
389 name = de->name;
390 inumber = de->inode;
391 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392
Andries Brouwer939b00d2007-02-12 00:52:49 -0800393 if (inumber != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 /* check for . and .. */
Andries Brouwer939b00d2007-02-12 00:52:49 -0800395 if (name[0] != '.')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 goto not_empty;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800397 if (!name[1]) {
398 if (inumber != inode->i_ino)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 goto not_empty;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800400 } else if (name[1] != '.')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 goto not_empty;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800402 else if (name[2])
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 goto not_empty;
404 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 }
406 dir_put_page(page);
407 }
408 return 1;
409
410not_empty:
411 dir_put_page(page);
412 return 0;
413}
414
415/* Releases the page */
416void minix_set_link(struct minix_dir_entry *de, struct page *page,
417 struct inode *inode)
418{
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200419 struct inode *dir = page->mapping->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
Nick Piggin4a66af92007-10-16 01:25:21 -0700421 loff_t pos = page_offset(page) +
422 (char *)de-(char*)page_address(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 int err;
424
425 lock_page(page);
Nick Piggin4a66af92007-10-16 01:25:21 -0700426
Christoph Hellwigf4e420d2010-06-04 11:29:56 +0200427 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 if (err == 0) {
Doug Graham9f6c1332009-09-22 16:48:00 -0700429 if (sbi->s_version == MINIX_V3)
430 ((minix3_dirent *) de)->inode = inode->i_ino;
431 else
432 de->inode = inode->i_ino;
Nick Piggin4a66af92007-10-16 01:25:21 -0700433 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 } else {
435 unlock_page(page);
436 }
437 dir_put_page(page);
438 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
439 mark_inode_dirty(dir);
440}
441
442struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
443{
444 struct page *page = dir_get_page(dir, 0);
445 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
446 struct minix_dir_entry *de = NULL;
447
448 if (!IS_ERR(page)) {
449 de = minix_next_entry(page_address(page), sbi);
450 *p = page;
451 }
452 return de;
453}
454
455ino_t minix_inode_by_name(struct dentry *dentry)
456{
457 struct page *page;
458 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
459 ino_t res = 0;
460
461 if (de) {
Doug Graham9f6c1332009-09-22 16:48:00 -0700462 struct address_space *mapping = page->mapping;
463 struct inode *inode = mapping->host;
464 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
465
466 if (sbi->s_version == MINIX_V3)
467 res = ((minix3_dirent *) de)->inode;
468 else
469 res = de->inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 dir_put_page(page);
471 }
472 return res;
473}