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1/*
2 * linux/fs/minix/dir.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * minix directory handling functions
7 *
8 * Updated to filesystem version 3 by Daniel Aragones
9 */
10
11#include "minix.h"
12#include <linux/buffer_head.h>
13#include <linux/highmem.h>
14#include <linux/swap.h>
15
16typedef struct minix_dir_entry minix_dirent;
17typedef struct minix3_dir_entry minix3_dirent;
18
19static int minix_readdir(struct file *, struct dir_context *);
20
21const struct file_operations minix_dir_operations = {
22 .llseek = generic_file_llseek,
23 .read = generic_read_dir,
24 .iterate = minix_readdir,
25 .fsync = generic_file_fsync,
26};
27
28static inline void dir_put_page(struct page *page)
29{
30 kunmap(page);
31 put_page(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_SIZE;
42
43 if (page_nr == (inode->i_size >> PAGE_SHIFT))
44 last_byte = inode->i_size & (PAGE_SIZE - 1);
45 return last_byte;
46}
47
48static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
49{
50 struct address_space *mapping = page->mapping;
51 struct inode *dir = mapping->host;
52 int err = 0;
53 block_write_end(NULL, mapping, pos, len, len, page, NULL);
54
55 if (pos+len > dir->i_size) {
56 i_size_write(dir, pos+len);
57 mark_inode_dirty(dir);
58 }
59 if (IS_DIRSYNC(dir))
60 err = write_one_page(page, 1);
61 else
62 unlock_page(page);
63 return err;
64}
65
66static struct page * dir_get_page(struct inode *dir, unsigned long n)
67{
68 struct address_space *mapping = dir->i_mapping;
69 struct page *page = read_mapping_page(mapping, n, NULL);
70 if (!IS_ERR(page))
71 kmap(page);
72 return page;
73}
74
75static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
76{
77 return (void*)((char*)de + sbi->s_dirsize);
78}
79
80static int minix_readdir(struct file *file, struct dir_context *ctx)
81{
82 struct inode *inode = file_inode(file);
83 struct super_block *sb = inode->i_sb;
84 struct minix_sb_info *sbi = minix_sb(sb);
85 unsigned chunk_size = sbi->s_dirsize;
86 unsigned long npages = dir_pages(inode);
87 unsigned long pos = ctx->pos;
88 unsigned offset;
89 unsigned long n;
90
91 ctx->pos = pos = ALIGN(pos, chunk_size);
92 if (pos >= inode->i_size)
93 return 0;
94
95 offset = pos & ~PAGE_MASK;
96 n = pos >> PAGE_SHIFT;
97
98 for ( ; n < npages; n++, offset = 0) {
99 char *p, *kaddr, *limit;
100 struct page *page = dir_get_page(inode, n);
101
102 if (IS_ERR(page))
103 continue;
104 kaddr = (char *)page_address(page);
105 p = kaddr+offset;
106 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
107 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
108 const char *name;
109 __u32 inumber;
110 if (sbi->s_version == MINIX_V3) {
111 minix3_dirent *de3 = (minix3_dirent *)p;
112 name = de3->name;
113 inumber = de3->inode;
114 } else {
115 minix_dirent *de = (minix_dirent *)p;
116 name = de->name;
117 inumber = de->inode;
118 }
119 if (inumber) {
120 unsigned l = strnlen(name, sbi->s_namelen);
121 if (!dir_emit(ctx, name, l,
122 inumber, DT_UNKNOWN)) {
123 dir_put_page(page);
124 return 0;
125 }
126 }
127 ctx->pos += chunk_size;
128 }
129 dir_put_page(page);
130 }
131 return 0;
132}
133
134static inline int namecompare(int len, int maxlen,
135 const char * name, const char * buffer)
136{
137 if (len < maxlen && buffer[len])
138 return 0;
139 return !memcmp(name, buffer, len);
140}
141
142/*
143 * minix_find_entry()
144 *
145 * finds an entry in the specified directory with the wanted name. It
146 * returns the cache buffer in which the entry was found, and the entry
147 * itself (as a parameter - res_dir). It does NOT read the inode of the
148 * entry - you'll have to do that yourself if you want to.
149 */
150minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
151{
152 const char * name = dentry->d_name.name;
153 int namelen = dentry->d_name.len;
154 struct inode * dir = d_inode(dentry->d_parent);
155 struct super_block * sb = dir->i_sb;
156 struct minix_sb_info * sbi = minix_sb(sb);
157 unsigned long n;
158 unsigned long npages = dir_pages(dir);
159 struct page *page = NULL;
160 char *p;
161
162 char *namx;
163 __u32 inumber;
164 *res_page = NULL;
165
166 for (n = 0; n < npages; n++) {
167 char *kaddr, *limit;
168
169 page = dir_get_page(dir, n);
170 if (IS_ERR(page))
171 continue;
172
173 kaddr = (char*)page_address(page);
174 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
175 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
176 if (sbi->s_version == MINIX_V3) {
177 minix3_dirent *de3 = (minix3_dirent *)p;
178 namx = de3->name;
179 inumber = de3->inode;
180 } else {
181 minix_dirent *de = (minix_dirent *)p;
182 namx = de->name;
183 inumber = de->inode;
184 }
185 if (!inumber)
186 continue;
187 if (namecompare(namelen, sbi->s_namelen, name, namx))
188 goto found;
189 }
190 dir_put_page(page);
191 }
192 return NULL;
193
194found:
195 *res_page = page;
196 return (minix_dirent *)p;
197}
198
199int minix_add_link(struct dentry *dentry, struct inode *inode)
200{
201 struct inode *dir = d_inode(dentry->d_parent);
202 const char * name = dentry->d_name.name;
203 int namelen = dentry->d_name.len;
204 struct super_block * sb = dir->i_sb;
205 struct minix_sb_info * sbi = minix_sb(sb);
206 struct page *page = NULL;
207 unsigned long npages = dir_pages(dir);
208 unsigned long n;
209 char *kaddr, *p;
210 minix_dirent *de;
211 minix3_dirent *de3;
212 loff_t pos;
213 int err;
214 char *namx = NULL;
215 __u32 inumber;
216
217 /*
218 * We take care of directory expansion in the same loop
219 * This code plays outside i_size, so it locks the page
220 * to protect that region.
221 */
222 for (n = 0; n <= npages; n++) {
223 char *limit, *dir_end;
224
225 page = dir_get_page(dir, n);
226 err = PTR_ERR(page);
227 if (IS_ERR(page))
228 goto out;
229 lock_page(page);
230 kaddr = (char*)page_address(page);
231 dir_end = kaddr + minix_last_byte(dir, n);
232 limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
233 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
234 de = (minix_dirent *)p;
235 de3 = (minix3_dirent *)p;
236 if (sbi->s_version == MINIX_V3) {
237 namx = de3->name;
238 inumber = de3->inode;
239 } else {
240 namx = de->name;
241 inumber = de->inode;
242 }
243 if (p == dir_end) {
244 /* We hit i_size */
245 if (sbi->s_version == MINIX_V3)
246 de3->inode = 0;
247 else
248 de->inode = 0;
249 goto got_it;
250 }
251 if (!inumber)
252 goto got_it;
253 err = -EEXIST;
254 if (namecompare(namelen, sbi->s_namelen, name, namx))
255 goto out_unlock;
256 }
257 unlock_page(page);
258 dir_put_page(page);
259 }
260 BUG();
261 return -EINVAL;
262
263got_it:
264 pos = page_offset(page) + p - (char *)page_address(page);
265 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
266 if (err)
267 goto out_unlock;
268 memcpy (namx, name, namelen);
269 if (sbi->s_version == MINIX_V3) {
270 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
271 de3->inode = inode->i_ino;
272 } else {
273 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
274 de->inode = inode->i_ino;
275 }
276 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
277 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
278 mark_inode_dirty(dir);
279out_put:
280 dir_put_page(page);
281out:
282 return err;
283out_unlock:
284 unlock_page(page);
285 goto out_put;
286}
287
288int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
289{
290 struct inode *inode = page->mapping->host;
291 char *kaddr = page_address(page);
292 loff_t pos = page_offset(page) + (char*)de - kaddr;
293 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
294 unsigned len = sbi->s_dirsize;
295 int err;
296
297 lock_page(page);
298 err = minix_prepare_chunk(page, pos, len);
299 if (err == 0) {
300 if (sbi->s_version == MINIX_V3)
301 ((minix3_dirent *) de)->inode = 0;
302 else
303 de->inode = 0;
304 err = dir_commit_chunk(page, pos, len);
305 } else {
306 unlock_page(page);
307 }
308 dir_put_page(page);
309 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
310 mark_inode_dirty(inode);
311 return err;
312}
313
314int minix_make_empty(struct inode *inode, struct inode *dir)
315{
316 struct page *page = grab_cache_page(inode->i_mapping, 0);
317 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
318 char *kaddr;
319 int err;
320
321 if (!page)
322 return -ENOMEM;
323 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
324 if (err) {
325 unlock_page(page);
326 goto fail;
327 }
328
329 kaddr = kmap_atomic(page);
330 memset(kaddr, 0, PAGE_SIZE);
331
332 if (sbi->s_version == MINIX_V3) {
333 minix3_dirent *de3 = (minix3_dirent *)kaddr;
334
335 de3->inode = inode->i_ino;
336 strcpy(de3->name, ".");
337 de3 = minix_next_entry(de3, sbi);
338 de3->inode = dir->i_ino;
339 strcpy(de3->name, "..");
340 } else {
341 minix_dirent *de = (minix_dirent *)kaddr;
342
343 de->inode = inode->i_ino;
344 strcpy(de->name, ".");
345 de = minix_next_entry(de, sbi);
346 de->inode = dir->i_ino;
347 strcpy(de->name, "..");
348 }
349 kunmap_atomic(kaddr);
350
351 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
352fail:
353 put_page(page);
354 return err;
355}
356
357/*
358 * routine to check that the specified directory is empty (for rmdir)
359 */
360int minix_empty_dir(struct inode * inode)
361{
362 struct page *page = NULL;
363 unsigned long i, npages = dir_pages(inode);
364 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
365 char *name;
366 __u32 inumber;
367
368 for (i = 0; i < npages; i++) {
369 char *p, *kaddr, *limit;
370
371 page = dir_get_page(inode, i);
372 if (IS_ERR(page))
373 continue;
374
375 kaddr = (char *)page_address(page);
376 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
377 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
378 if (sbi->s_version == MINIX_V3) {
379 minix3_dirent *de3 = (minix3_dirent *)p;
380 name = de3->name;
381 inumber = de3->inode;
382 } else {
383 minix_dirent *de = (minix_dirent *)p;
384 name = de->name;
385 inumber = de->inode;
386 }
387
388 if (inumber != 0) {
389 /* check for . and .. */
390 if (name[0] != '.')
391 goto not_empty;
392 if (!name[1]) {
393 if (inumber != inode->i_ino)
394 goto not_empty;
395 } else if (name[1] != '.')
396 goto not_empty;
397 else if (name[2])
398 goto not_empty;
399 }
400 }
401 dir_put_page(page);
402 }
403 return 1;
404
405not_empty:
406 dir_put_page(page);
407 return 0;
408}
409
410/* Releases the page */
411void minix_set_link(struct minix_dir_entry *de, struct page *page,
412 struct inode *inode)
413{
414 struct inode *dir = page->mapping->host;
415 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
416 loff_t pos = page_offset(page) +
417 (char *)de-(char*)page_address(page);
418 int err;
419
420 lock_page(page);
421
422 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
423 if (err == 0) {
424 if (sbi->s_version == MINIX_V3)
425 ((minix3_dirent *) de)->inode = inode->i_ino;
426 else
427 de->inode = inode->i_ino;
428 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
429 } else {
430 unlock_page(page);
431 }
432 dir_put_page(page);
433 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
434 mark_inode_dirty(dir);
435}
436
437struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
438{
439 struct page *page = dir_get_page(dir, 0);
440 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
441 struct minix_dir_entry *de = NULL;
442
443 if (!IS_ERR(page)) {
444 de = minix_next_entry(page_address(page), sbi);
445 *p = page;
446 }
447 return de;
448}
449
450ino_t minix_inode_by_name(struct dentry *dentry)
451{
452 struct page *page;
453 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
454 ino_t res = 0;
455
456 if (de) {
457 struct address_space *mapping = page->mapping;
458 struct inode *inode = mapping->host;
459 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
460
461 if (sbi->s_version == MINIX_V3)
462 res = ((minix3_dirent *) de)->inode;
463 else
464 res = de->inode;
465 dir_put_page(page);
466 }
467 return res;
468}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/minix/dir.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 *
7 * minix directory handling functions
8 *
9 * Updated to filesystem version 3 by Daniel Aragones
10 */
11
12#include "minix.h"
13#include <linux/buffer_head.h>
14#include <linux/highmem.h>
15#include <linux/swap.h>
16
17typedef struct minix_dir_entry minix_dirent;
18typedef struct minix3_dir_entry minix3_dirent;
19
20static int minix_readdir(struct file *, struct dir_context *);
21
22const struct file_operations minix_dir_operations = {
23 .llseek = generic_file_llseek,
24 .read = generic_read_dir,
25 .iterate_shared = minix_readdir,
26 .fsync = generic_file_fsync,
27};
28
29static inline void dir_put_page(struct page *page)
30{
31 kunmap(page);
32 put_page(page);
33}
34
35/*
36 * Return the offset into page `page_nr' of the last valid
37 * byte in that page, plus one.
38 */
39static unsigned
40minix_last_byte(struct inode *inode, unsigned long page_nr)
41{
42 unsigned last_byte = PAGE_SIZE;
43
44 if (page_nr == (inode->i_size >> PAGE_SHIFT))
45 last_byte = inode->i_size & (PAGE_SIZE - 1);
46 return last_byte;
47}
48
49static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
50{
51 struct address_space *mapping = page->mapping;
52 struct inode *dir = mapping->host;
53 int err = 0;
54 block_write_end(NULL, mapping, pos, len, len, page, NULL);
55
56 if (pos+len > dir->i_size) {
57 i_size_write(dir, pos+len);
58 mark_inode_dirty(dir);
59 }
60 if (IS_DIRSYNC(dir))
61 err = write_one_page(page);
62 else
63 unlock_page(page);
64 return err;
65}
66
67static struct page * dir_get_page(struct inode *dir, unsigned long n)
68{
69 struct address_space *mapping = dir->i_mapping;
70 struct page *page = read_mapping_page(mapping, n, NULL);
71 if (!IS_ERR(page))
72 kmap(page);
73 return page;
74}
75
76static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
77{
78 return (void*)((char*)de + sbi->s_dirsize);
79}
80
81static int minix_readdir(struct file *file, struct dir_context *ctx)
82{
83 struct inode *inode = file_inode(file);
84 struct super_block *sb = inode->i_sb;
85 struct minix_sb_info *sbi = minix_sb(sb);
86 unsigned chunk_size = sbi->s_dirsize;
87 unsigned long npages = dir_pages(inode);
88 unsigned long pos = ctx->pos;
89 unsigned offset;
90 unsigned long n;
91
92 ctx->pos = pos = ALIGN(pos, chunk_size);
93 if (pos >= inode->i_size)
94 return 0;
95
96 offset = pos & ~PAGE_MASK;
97 n = pos >> PAGE_SHIFT;
98
99 for ( ; n < npages; n++, offset = 0) {
100 char *p, *kaddr, *limit;
101 struct page *page = dir_get_page(inode, n);
102
103 if (IS_ERR(page))
104 continue;
105 kaddr = (char *)page_address(page);
106 p = kaddr+offset;
107 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
108 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
109 const char *name;
110 __u32 inumber;
111 if (sbi->s_version == MINIX_V3) {
112 minix3_dirent *de3 = (minix3_dirent *)p;
113 name = de3->name;
114 inumber = de3->inode;
115 } else {
116 minix_dirent *de = (minix_dirent *)p;
117 name = de->name;
118 inumber = de->inode;
119 }
120 if (inumber) {
121 unsigned l = strnlen(name, sbi->s_namelen);
122 if (!dir_emit(ctx, name, l,
123 inumber, DT_UNKNOWN)) {
124 dir_put_page(page);
125 return 0;
126 }
127 }
128 ctx->pos += chunk_size;
129 }
130 dir_put_page(page);
131 }
132 return 0;
133}
134
135static inline int namecompare(int len, int maxlen,
136 const char * name, const char * buffer)
137{
138 if (len < maxlen && buffer[len])
139 return 0;
140 return !memcmp(name, buffer, len);
141}
142
143/*
144 * minix_find_entry()
145 *
146 * finds an entry in the specified directory with the wanted name. It
147 * returns the cache buffer in which the entry was found, and the entry
148 * itself (as a parameter - res_dir). It does NOT read the inode of the
149 * entry - you'll have to do that yourself if you want to.
150 */
151minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
152{
153 const char * name = dentry->d_name.name;
154 int namelen = dentry->d_name.len;
155 struct inode * dir = d_inode(dentry->d_parent);
156 struct super_block * sb = dir->i_sb;
157 struct minix_sb_info * sbi = minix_sb(sb);
158 unsigned long n;
159 unsigned long npages = dir_pages(dir);
160 struct page *page = NULL;
161 char *p;
162
163 char *namx;
164 __u32 inumber;
165 *res_page = NULL;
166
167 for (n = 0; n < npages; n++) {
168 char *kaddr, *limit;
169
170 page = dir_get_page(dir, n);
171 if (IS_ERR(page))
172 continue;
173
174 kaddr = (char*)page_address(page);
175 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
176 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
177 if (sbi->s_version == MINIX_V3) {
178 minix3_dirent *de3 = (minix3_dirent *)p;
179 namx = de3->name;
180 inumber = de3->inode;
181 } else {
182 minix_dirent *de = (minix_dirent *)p;
183 namx = de->name;
184 inumber = de->inode;
185 }
186 if (!inumber)
187 continue;
188 if (namecompare(namelen, sbi->s_namelen, name, namx))
189 goto found;
190 }
191 dir_put_page(page);
192 }
193 return NULL;
194
195found:
196 *res_page = page;
197 return (minix_dirent *)p;
198}
199
200int minix_add_link(struct dentry *dentry, struct inode *inode)
201{
202 struct inode *dir = d_inode(dentry->d_parent);
203 const char * name = dentry->d_name.name;
204 int namelen = dentry->d_name.len;
205 struct super_block * sb = dir->i_sb;
206 struct minix_sb_info * sbi = minix_sb(sb);
207 struct page *page = NULL;
208 unsigned long npages = dir_pages(dir);
209 unsigned long n;
210 char *kaddr, *p;
211 minix_dirent *de;
212 minix3_dirent *de3;
213 loff_t pos;
214 int err;
215 char *namx = NULL;
216 __u32 inumber;
217
218 /*
219 * We take care of directory expansion in the same loop
220 * This code plays outside i_size, so it locks the page
221 * to protect that region.
222 */
223 for (n = 0; n <= npages; n++) {
224 char *limit, *dir_end;
225
226 page = dir_get_page(dir, n);
227 err = PTR_ERR(page);
228 if (IS_ERR(page))
229 goto out;
230 lock_page(page);
231 kaddr = (char*)page_address(page);
232 dir_end = kaddr + minix_last_byte(dir, n);
233 limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
234 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
235 de = (minix_dirent *)p;
236 de3 = (minix3_dirent *)p;
237 if (sbi->s_version == MINIX_V3) {
238 namx = de3->name;
239 inumber = de3->inode;
240 } else {
241 namx = de->name;
242 inumber = de->inode;
243 }
244 if (p == dir_end) {
245 /* We hit i_size */
246 if (sbi->s_version == MINIX_V3)
247 de3->inode = 0;
248 else
249 de->inode = 0;
250 goto got_it;
251 }
252 if (!inumber)
253 goto got_it;
254 err = -EEXIST;
255 if (namecompare(namelen, sbi->s_namelen, name, namx))
256 goto out_unlock;
257 }
258 unlock_page(page);
259 dir_put_page(page);
260 }
261 BUG();
262 return -EINVAL;
263
264got_it:
265 pos = page_offset(page) + p - (char *)page_address(page);
266 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
267 if (err)
268 goto out_unlock;
269 memcpy (namx, name, namelen);
270 if (sbi->s_version == MINIX_V3) {
271 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
272 de3->inode = inode->i_ino;
273 } else {
274 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
275 de->inode = inode->i_ino;
276 }
277 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
278 dir->i_mtime = dir->i_ctime = current_time(dir);
279 mark_inode_dirty(dir);
280out_put:
281 dir_put_page(page);
282out:
283 return err;
284out_unlock:
285 unlock_page(page);
286 goto out_put;
287}
288
289int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
290{
291 struct inode *inode = page->mapping->host;
292 char *kaddr = page_address(page);
293 loff_t pos = page_offset(page) + (char*)de - kaddr;
294 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
295 unsigned len = sbi->s_dirsize;
296 int err;
297
298 lock_page(page);
299 err = minix_prepare_chunk(page, pos, len);
300 if (err == 0) {
301 if (sbi->s_version == MINIX_V3)
302 ((minix3_dirent *) de)->inode = 0;
303 else
304 de->inode = 0;
305 err = dir_commit_chunk(page, pos, len);
306 } else {
307 unlock_page(page);
308 }
309 dir_put_page(page);
310 inode->i_ctime = inode->i_mtime = current_time(inode);
311 mark_inode_dirty(inode);
312 return err;
313}
314
315int minix_make_empty(struct inode *inode, struct inode *dir)
316{
317 struct page *page = grab_cache_page(inode->i_mapping, 0);
318 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
319 char *kaddr;
320 int err;
321
322 if (!page)
323 return -ENOMEM;
324 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
325 if (err) {
326 unlock_page(page);
327 goto fail;
328 }
329
330 kaddr = kmap_atomic(page);
331 memset(kaddr, 0, PAGE_SIZE);
332
333 if (sbi->s_version == MINIX_V3) {
334 minix3_dirent *de3 = (minix3_dirent *)kaddr;
335
336 de3->inode = inode->i_ino;
337 strcpy(de3->name, ".");
338 de3 = minix_next_entry(de3, sbi);
339 de3->inode = dir->i_ino;
340 strcpy(de3->name, "..");
341 } else {
342 minix_dirent *de = (minix_dirent *)kaddr;
343
344 de->inode = inode->i_ino;
345 strcpy(de->name, ".");
346 de = minix_next_entry(de, sbi);
347 de->inode = dir->i_ino;
348 strcpy(de->name, "..");
349 }
350 kunmap_atomic(kaddr);
351
352 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
353fail:
354 put_page(page);
355 return err;
356}
357
358/*
359 * routine to check that the specified directory is empty (for rmdir)
360 */
361int minix_empty_dir(struct inode * inode)
362{
363 struct page *page = NULL;
364 unsigned long i, npages = dir_pages(inode);
365 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
366 char *name;
367 __u32 inumber;
368
369 for (i = 0; i < npages; i++) {
370 char *p, *kaddr, *limit;
371
372 page = dir_get_page(inode, i);
373 if (IS_ERR(page))
374 continue;
375
376 kaddr = (char *)page_address(page);
377 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
378 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
379 if (sbi->s_version == MINIX_V3) {
380 minix3_dirent *de3 = (minix3_dirent *)p;
381 name = de3->name;
382 inumber = de3->inode;
383 } else {
384 minix_dirent *de = (minix_dirent *)p;
385 name = de->name;
386 inumber = de->inode;
387 }
388
389 if (inumber != 0) {
390 /* check for . and .. */
391 if (name[0] != '.')
392 goto not_empty;
393 if (!name[1]) {
394 if (inumber != inode->i_ino)
395 goto not_empty;
396 } else if (name[1] != '.')
397 goto not_empty;
398 else if (name[2])
399 goto not_empty;
400 }
401 }
402 dir_put_page(page);
403 }
404 return 1;
405
406not_empty:
407 dir_put_page(page);
408 return 0;
409}
410
411/* Releases the page */
412void minix_set_link(struct minix_dir_entry *de, struct page *page,
413 struct inode *inode)
414{
415 struct inode *dir = page->mapping->host;
416 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
417 loff_t pos = page_offset(page) +
418 (char *)de-(char*)page_address(page);
419 int err;
420
421 lock_page(page);
422
423 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
424 if (err == 0) {
425 if (sbi->s_version == MINIX_V3)
426 ((minix3_dirent *) de)->inode = inode->i_ino;
427 else
428 de->inode = inode->i_ino;
429 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
430 } else {
431 unlock_page(page);
432 }
433 dir_put_page(page);
434 dir->i_mtime = dir->i_ctime = current_time(dir);
435 mark_inode_dirty(dir);
436}
437
438struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
439{
440 struct page *page = dir_get_page(dir, 0);
441 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
442 struct minix_dir_entry *de = NULL;
443
444 if (!IS_ERR(page)) {
445 de = minix_next_entry(page_address(page), sbi);
446 *p = page;
447 }
448 return de;
449}
450
451ino_t minix_inode_by_name(struct dentry *dentry)
452{
453 struct page *page;
454 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
455 ino_t res = 0;
456
457 if (de) {
458 struct address_space *mapping = page->mapping;
459 struct inode *inode = mapping->host;
460 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
461
462 if (sbi->s_version == MINIX_V3)
463 res = ((minix3_dirent *) de)->inode;
464 else
465 res = de->inode;
466 dir_put_page(page);
467 }
468 return res;
469}