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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 *, void *, filldir_t);
20
21const struct file_operations minix_dir_operations = {
22 .llseek = generic_file_llseek,
23 .read = generic_read_dir,
24 .readdir = minix_readdir,
25 .fsync = generic_file_fsync,
26};
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
53static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
54{
55 struct address_space *mapping = page->mapping;
56 struct inode *dir = mapping->host;
57 int err = 0;
58 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 }
64 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;
74 struct page *page = read_mapping_page(mapping, n, NULL);
75 if (!IS_ERR(page))
76 kmap(page);
77 return page;
78}
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
85static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir)
86{
87 unsigned long pos = filp->f_pos;
88 struct inode *inode = filp->f_path.dentry->d_inode;
89 struct super_block *sb = inode->i_sb;
90 unsigned offset = pos & ~PAGE_CACHE_MASK;
91 unsigned long n = pos >> PAGE_CACHE_SHIFT;
92 unsigned long npages = dir_pages(inode);
93 struct minix_sb_info *sbi = minix_sb(sb);
94 unsigned chunk_size = sbi->s_dirsize;
95 char *name;
96 __u32 inumber;
97
98 pos = (pos + chunk_size-1) & ~(chunk_size-1);
99 if (pos >= inode->i_size)
100 goto done;
101
102 for ( ; n < npages; n++, offset = 0) {
103 char *p, *kaddr, *limit;
104 struct page *page = dir_get_page(inode, n);
105
106 if (IS_ERR(page))
107 continue;
108 kaddr = (char *)page_address(page);
109 p = kaddr+offset;
110 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
111 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
112 if (sbi->s_version == MINIX_V3) {
113 minix3_dirent *de3 = (minix3_dirent *)p;
114 name = de3->name;
115 inumber = de3->inode;
116 } else {
117 minix_dirent *de = (minix_dirent *)p;
118 name = de->name;
119 inumber = de->inode;
120 }
121 if (inumber) {
122 int over;
123
124 unsigned l = strnlen(name, sbi->s_namelen);
125 offset = p - kaddr;
126 over = filldir(dirent, name, l,
127 (n << PAGE_CACHE_SHIFT) | offset,
128 inumber, DT_UNKNOWN);
129 if (over) {
130 dir_put_page(page);
131 goto done;
132 }
133 }
134 }
135 dir_put_page(page);
136 }
137
138done:
139 filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
140 return 0;
141}
142
143static inline int namecompare(int len, int maxlen,
144 const char * name, const char * buffer)
145{
146 if (len < maxlen && buffer[len])
147 return 0;
148 return !memcmp(name, buffer, len);
149}
150
151/*
152 * minix_find_entry()
153 *
154 * finds an entry in the specified directory with the wanted name. It
155 * returns the cache buffer in which the entry was found, and the entry
156 * itself (as a parameter - res_dir). It does NOT read the inode of the
157 * entry - you'll have to do that yourself if you want to.
158 */
159minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
160{
161 const char * name = dentry->d_name.name;
162 int namelen = dentry->d_name.len;
163 struct inode * dir = dentry->d_parent->d_inode;
164 struct super_block * sb = dir->i_sb;
165 struct minix_sb_info * sbi = minix_sb(sb);
166 unsigned long n;
167 unsigned long npages = dir_pages(dir);
168 struct page *page = NULL;
169 char *p;
170
171 char *namx;
172 __u32 inumber;
173 *res_page = NULL;
174
175 for (n = 0; n < npages; n++) {
176 char *kaddr, *limit;
177
178 page = dir_get_page(dir, n);
179 if (IS_ERR(page))
180 continue;
181
182 kaddr = (char*)page_address(page);
183 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
184 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
185 if (sbi->s_version == MINIX_V3) {
186 minix3_dirent *de3 = (minix3_dirent *)p;
187 namx = de3->name;
188 inumber = de3->inode;
189 } else {
190 minix_dirent *de = (minix_dirent *)p;
191 namx = de->name;
192 inumber = de->inode;
193 }
194 if (!inumber)
195 continue;
196 if (namecompare(namelen, sbi->s_namelen, name, namx))
197 goto found;
198 }
199 dir_put_page(page);
200 }
201 return NULL;
202
203found:
204 *res_page = page;
205 return (minix_dirent *)p;
206}
207
208int minix_add_link(struct dentry *dentry, struct inode *inode)
209{
210 struct inode *dir = dentry->d_parent->d_inode;
211 const char * name = dentry->d_name.name;
212 int namelen = dentry->d_name.len;
213 struct super_block * sb = dir->i_sb;
214 struct minix_sb_info * sbi = minix_sb(sb);
215 struct page *page = NULL;
216 unsigned long npages = dir_pages(dir);
217 unsigned long n;
218 char *kaddr, *p;
219 minix_dirent *de;
220 minix3_dirent *de3;
221 loff_t pos;
222 int err;
223 char *namx = NULL;
224 __u32 inumber;
225
226 /*
227 * We take care of directory expansion in the same loop
228 * This code plays outside i_size, so it locks the page
229 * to protect that region.
230 */
231 for (n = 0; n <= npages; n++) {
232 char *limit, *dir_end;
233
234 page = dir_get_page(dir, n);
235 err = PTR_ERR(page);
236 if (IS_ERR(page))
237 goto out;
238 lock_page(page);
239 kaddr = (char*)page_address(page);
240 dir_end = kaddr + minix_last_byte(dir, n);
241 limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
242 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
243 de = (minix_dirent *)p;
244 de3 = (minix3_dirent *)p;
245 if (sbi->s_version == MINIX_V3) {
246 namx = de3->name;
247 inumber = de3->inode;
248 } else {
249 namx = de->name;
250 inumber = de->inode;
251 }
252 if (p == dir_end) {
253 /* We hit i_size */
254 if (sbi->s_version == MINIX_V3)
255 de3->inode = 0;
256 else
257 de->inode = 0;
258 goto got_it;
259 }
260 if (!inumber)
261 goto got_it;
262 err = -EEXIST;
263 if (namecompare(namelen, sbi->s_namelen, name, namx))
264 goto out_unlock;
265 }
266 unlock_page(page);
267 dir_put_page(page);
268 }
269 BUG();
270 return -EINVAL;
271
272got_it:
273 pos = page_offset(page) + p - (char *)page_address(page);
274 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
275 if (err)
276 goto out_unlock;
277 memcpy (namx, name, namelen);
278 if (sbi->s_version == MINIX_V3) {
279 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
280 de3->inode = inode->i_ino;
281 } else {
282 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
283 de->inode = inode->i_ino;
284 }
285 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
286 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
287 mark_inode_dirty(dir);
288out_put:
289 dir_put_page(page);
290out:
291 return err;
292out_unlock:
293 unlock_page(page);
294 goto out_put;
295}
296
297int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
298{
299 struct inode *inode = page->mapping->host;
300 char *kaddr = page_address(page);
301 loff_t pos = page_offset(page) + (char*)de - kaddr;
302 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
303 unsigned len = sbi->s_dirsize;
304 int err;
305
306 lock_page(page);
307 err = minix_prepare_chunk(page, pos, len);
308 if (err == 0) {
309 if (sbi->s_version == MINIX_V3)
310 ((minix3_dirent *) de)->inode = 0;
311 else
312 de->inode = 0;
313 err = dir_commit_chunk(page, pos, len);
314 } else {
315 unlock_page(page);
316 }
317 dir_put_page(page);
318 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
319 mark_inode_dirty(inode);
320 return err;
321}
322
323int minix_make_empty(struct inode *inode, struct inode *dir)
324{
325 struct page *page = grab_cache_page(inode->i_mapping, 0);
326 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
327 char *kaddr;
328 int err;
329
330 if (!page)
331 return -ENOMEM;
332 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
333 if (err) {
334 unlock_page(page);
335 goto fail;
336 }
337
338 kaddr = kmap_atomic(page);
339 memset(kaddr, 0, PAGE_CACHE_SIZE);
340
341 if (sbi->s_version == MINIX_V3) {
342 minix3_dirent *de3 = (minix3_dirent *)kaddr;
343
344 de3->inode = inode->i_ino;
345 strcpy(de3->name, ".");
346 de3 = minix_next_entry(de3, sbi);
347 de3->inode = dir->i_ino;
348 strcpy(de3->name, "..");
349 } else {
350 minix_dirent *de = (minix_dirent *)kaddr;
351
352 de->inode = inode->i_ino;
353 strcpy(de->name, ".");
354 de = minix_next_entry(de, sbi);
355 de->inode = dir->i_ino;
356 strcpy(de->name, "..");
357 }
358 kunmap_atomic(kaddr);
359
360 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
361fail:
362 page_cache_release(page);
363 return err;
364}
365
366/*
367 * routine to check that the specified directory is empty (for rmdir)
368 */
369int minix_empty_dir(struct inode * inode)
370{
371 struct page *page = NULL;
372 unsigned long i, npages = dir_pages(inode);
373 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
374 char *name;
375 __u32 inumber;
376
377 for (i = 0; i < npages; i++) {
378 char *p, *kaddr, *limit;
379
380 page = dir_get_page(inode, i);
381 if (IS_ERR(page))
382 continue;
383
384 kaddr = (char *)page_address(page);
385 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
386 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
387 if (sbi->s_version == MINIX_V3) {
388 minix3_dirent *de3 = (minix3_dirent *)p;
389 name = de3->name;
390 inumber = de3->inode;
391 } else {
392 minix_dirent *de = (minix_dirent *)p;
393 name = de->name;
394 inumber = de->inode;
395 }
396
397 if (inumber != 0) {
398 /* check for . and .. */
399 if (name[0] != '.')
400 goto not_empty;
401 if (!name[1]) {
402 if (inumber != inode->i_ino)
403 goto not_empty;
404 } else if (name[1] != '.')
405 goto not_empty;
406 else if (name[2])
407 goto not_empty;
408 }
409 }
410 dir_put_page(page);
411 }
412 return 1;
413
414not_empty:
415 dir_put_page(page);
416 return 0;
417}
418
419/* Releases the page */
420void minix_set_link(struct minix_dir_entry *de, struct page *page,
421 struct inode *inode)
422{
423 struct inode *dir = page->mapping->host;
424 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
425 loff_t pos = page_offset(page) +
426 (char *)de-(char*)page_address(page);
427 int err;
428
429 lock_page(page);
430
431 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
432 if (err == 0) {
433 if (sbi->s_version == MINIX_V3)
434 ((minix3_dirent *) de)->inode = inode->i_ino;
435 else
436 de->inode = inode->i_ino;
437 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
438 } else {
439 unlock_page(page);
440 }
441 dir_put_page(page);
442 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
443 mark_inode_dirty(dir);
444}
445
446struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
447{
448 struct page *page = dir_get_page(dir, 0);
449 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
450 struct minix_dir_entry *de = NULL;
451
452 if (!IS_ERR(page)) {
453 de = minix_next_entry(page_address(page), sbi);
454 *p = page;
455 }
456 return de;
457}
458
459ino_t minix_inode_by_name(struct dentry *dentry)
460{
461 struct page *page;
462 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
463 ino_t res = 0;
464
465 if (de) {
466 struct address_space *mapping = page->mapping;
467 struct inode *inode = mapping->host;
468 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
469
470 if (sbi->s_version == MINIX_V3)
471 res = ((minix3_dirent *) de)->inode;
472 else
473 res = de->inode;
474 dir_put_page(page);
475 }
476 return res;
477}
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
29/*
30 * Return the offset into page `page_nr' of the last valid
31 * byte in that page, plus one.
32 */
33static unsigned
34minix_last_byte(struct inode *inode, unsigned long page_nr)
35{
36 unsigned last_byte = PAGE_SIZE;
37
38 if (page_nr == (inode->i_size >> PAGE_SHIFT))
39 last_byte = inode->i_size & (PAGE_SIZE - 1);
40 return last_byte;
41}
42
43static void dir_commit_chunk(struct folio *folio, loff_t pos, unsigned len)
44{
45 struct address_space *mapping = folio->mapping;
46 struct inode *dir = mapping->host;
47
48 block_write_end(NULL, mapping, pos, len, len, folio, NULL);
49
50 if (pos+len > dir->i_size) {
51 i_size_write(dir, pos+len);
52 mark_inode_dirty(dir);
53 }
54 folio_unlock(folio);
55}
56
57static int minix_handle_dirsync(struct inode *dir)
58{
59 int err;
60
61 err = filemap_write_and_wait(dir->i_mapping);
62 if (!err)
63 err = sync_inode_metadata(dir, 1);
64 return err;
65}
66
67static void *dir_get_folio(struct inode *dir, unsigned long n,
68 struct folio **foliop)
69{
70 struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL);
71
72 if (IS_ERR(folio))
73 return ERR_CAST(folio);
74 *foliop = folio;
75 return kmap_local_folio(folio, 0);
76}
77
78static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
79{
80 return (void*)((char*)de + sbi->s_dirsize);
81}
82
83static int minix_readdir(struct file *file, struct dir_context *ctx)
84{
85 struct inode *inode = file_inode(file);
86 struct super_block *sb = inode->i_sb;
87 struct minix_sb_info *sbi = minix_sb(sb);
88 unsigned chunk_size = sbi->s_dirsize;
89 unsigned long npages = dir_pages(inode);
90 unsigned long pos = ctx->pos;
91 unsigned offset;
92 unsigned long n;
93
94 ctx->pos = pos = ALIGN(pos, chunk_size);
95 if (pos >= inode->i_size)
96 return 0;
97
98 offset = pos & ~PAGE_MASK;
99 n = pos >> PAGE_SHIFT;
100
101 for ( ; n < npages; n++, offset = 0) {
102 char *p, *kaddr, *limit;
103 struct folio *folio;
104
105 kaddr = dir_get_folio(inode, n, &folio);
106 if (IS_ERR(kaddr))
107 continue;
108 p = kaddr+offset;
109 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
110 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
111 const char *name;
112 __u32 inumber;
113 if (sbi->s_version == MINIX_V3) {
114 minix3_dirent *de3 = (minix3_dirent *)p;
115 name = de3->name;
116 inumber = de3->inode;
117 } else {
118 minix_dirent *de = (minix_dirent *)p;
119 name = de->name;
120 inumber = de->inode;
121 }
122 if (inumber) {
123 unsigned l = strnlen(name, sbi->s_namelen);
124 if (!dir_emit(ctx, name, l,
125 inumber, DT_UNKNOWN)) {
126 folio_release_kmap(folio, p);
127 return 0;
128 }
129 }
130 ctx->pos += chunk_size;
131 }
132 folio_release_kmap(folio, kaddr);
133 }
134 return 0;
135}
136
137static inline int namecompare(int len, int maxlen,
138 const char * name, const char * buffer)
139{
140 if (len < maxlen && buffer[len])
141 return 0;
142 return !memcmp(name, buffer, len);
143}
144
145/*
146 * minix_find_entry()
147 *
148 * finds an entry in the specified directory with the wanted name.
149 * It does NOT read the inode of the
150 * entry - you'll have to do that yourself if you want to.
151 *
152 * On Success folio_release_kmap() should be called on *foliop.
153 */
154minix_dirent *minix_find_entry(struct dentry *dentry, struct folio **foliop)
155{
156 const char * name = dentry->d_name.name;
157 int namelen = dentry->d_name.len;
158 struct inode * dir = d_inode(dentry->d_parent);
159 struct super_block * sb = dir->i_sb;
160 struct minix_sb_info * sbi = minix_sb(sb);
161 unsigned long n;
162 unsigned long npages = dir_pages(dir);
163 char *p;
164
165 char *namx;
166 __u32 inumber;
167
168 for (n = 0; n < npages; n++) {
169 char *kaddr, *limit;
170
171 kaddr = dir_get_folio(dir, n, foliop);
172 if (IS_ERR(kaddr))
173 continue;
174
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 folio_release_kmap(*foliop, kaddr);
192 }
193 return NULL;
194
195found:
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 folio *folio = 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 kaddr = dir_get_folio(dir, n, &folio);
226 if (IS_ERR(kaddr))
227 return PTR_ERR(kaddr);
228 folio_lock(folio);
229 dir_end = kaddr + minix_last_byte(dir, n);
230 limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
231 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
232 de = (minix_dirent *)p;
233 de3 = (minix3_dirent *)p;
234 if (sbi->s_version == MINIX_V3) {
235 namx = de3->name;
236 inumber = de3->inode;
237 } else {
238 namx = de->name;
239 inumber = de->inode;
240 }
241 if (p == dir_end) {
242 /* We hit i_size */
243 if (sbi->s_version == MINIX_V3)
244 de3->inode = 0;
245 else
246 de->inode = 0;
247 goto got_it;
248 }
249 if (!inumber)
250 goto got_it;
251 err = -EEXIST;
252 if (namecompare(namelen, sbi->s_namelen, name, namx))
253 goto out_unlock;
254 }
255 folio_unlock(folio);
256 folio_release_kmap(folio, kaddr);
257 }
258 BUG();
259 return -EINVAL;
260
261got_it:
262 pos = folio_pos(folio) + offset_in_folio(folio, p);
263 err = minix_prepare_chunk(folio, pos, sbi->s_dirsize);
264 if (err)
265 goto out_unlock;
266 memcpy (namx, name, namelen);
267 if (sbi->s_version == MINIX_V3) {
268 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
269 de3->inode = inode->i_ino;
270 } else {
271 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
272 de->inode = inode->i_ino;
273 }
274 dir_commit_chunk(folio, pos, sbi->s_dirsize);
275 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
276 mark_inode_dirty(dir);
277 err = minix_handle_dirsync(dir);
278out_put:
279 folio_release_kmap(folio, kaddr);
280 return err;
281out_unlock:
282 folio_unlock(folio);
283 goto out_put;
284}
285
286int minix_delete_entry(struct minix_dir_entry *de, struct folio *folio)
287{
288 struct inode *inode = folio->mapping->host;
289 loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
290 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
291 unsigned len = sbi->s_dirsize;
292 int err;
293
294 folio_lock(folio);
295 err = minix_prepare_chunk(folio, pos, len);
296 if (err) {
297 folio_unlock(folio);
298 return err;
299 }
300 if (sbi->s_version == MINIX_V3)
301 ((minix3_dirent *)de)->inode = 0;
302 else
303 de->inode = 0;
304 dir_commit_chunk(folio, pos, len);
305 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
306 mark_inode_dirty(inode);
307 return minix_handle_dirsync(inode);
308}
309
310int minix_make_empty(struct inode *inode, struct inode *dir)
311{
312 struct folio *folio = filemap_grab_folio(inode->i_mapping, 0);
313 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
314 char *kaddr;
315 int err;
316
317 if (IS_ERR(folio))
318 return PTR_ERR(folio);
319 err = minix_prepare_chunk(folio, 0, 2 * sbi->s_dirsize);
320 if (err) {
321 folio_unlock(folio);
322 goto fail;
323 }
324
325 kaddr = kmap_local_folio(folio, 0);
326 memset(kaddr, 0, folio_size(folio));
327
328 if (sbi->s_version == MINIX_V3) {
329 minix3_dirent *de3 = (minix3_dirent *)kaddr;
330
331 de3->inode = inode->i_ino;
332 strcpy(de3->name, ".");
333 de3 = minix_next_entry(de3, sbi);
334 de3->inode = dir->i_ino;
335 strcpy(de3->name, "..");
336 } else {
337 minix_dirent *de = (minix_dirent *)kaddr;
338
339 de->inode = inode->i_ino;
340 strcpy(de->name, ".");
341 de = minix_next_entry(de, sbi);
342 de->inode = dir->i_ino;
343 strcpy(de->name, "..");
344 }
345 kunmap_local(kaddr);
346
347 dir_commit_chunk(folio, 0, 2 * sbi->s_dirsize);
348 err = minix_handle_dirsync(inode);
349fail:
350 folio_put(folio);
351 return err;
352}
353
354/*
355 * routine to check that the specified directory is empty (for rmdir)
356 */
357int minix_empty_dir(struct inode * inode)
358{
359 struct folio *folio = NULL;
360 unsigned long i, npages = dir_pages(inode);
361 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
362 char *name, *kaddr;
363 __u32 inumber;
364
365 for (i = 0; i < npages; i++) {
366 char *p, *limit;
367
368 kaddr = dir_get_folio(inode, i, &folio);
369 if (IS_ERR(kaddr))
370 continue;
371
372 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
373 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
374 if (sbi->s_version == MINIX_V3) {
375 minix3_dirent *de3 = (minix3_dirent *)p;
376 name = de3->name;
377 inumber = de3->inode;
378 } else {
379 minix_dirent *de = (minix_dirent *)p;
380 name = de->name;
381 inumber = de->inode;
382 }
383
384 if (inumber != 0) {
385 /* check for . and .. */
386 if (name[0] != '.')
387 goto not_empty;
388 if (!name[1]) {
389 if (inumber != inode->i_ino)
390 goto not_empty;
391 } else if (name[1] != '.')
392 goto not_empty;
393 else if (name[2])
394 goto not_empty;
395 }
396 }
397 folio_release_kmap(folio, kaddr);
398 }
399 return 1;
400
401not_empty:
402 folio_release_kmap(folio, kaddr);
403 return 0;
404}
405
406/* Releases the page */
407int minix_set_link(struct minix_dir_entry *de, struct folio *folio,
408 struct inode *inode)
409{
410 struct inode *dir = folio->mapping->host;
411 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
412 loff_t pos = folio_pos(folio) + offset_in_folio(folio, de);
413 int err;
414
415 folio_lock(folio);
416 err = minix_prepare_chunk(folio, pos, sbi->s_dirsize);
417 if (err) {
418 folio_unlock(folio);
419 return err;
420 }
421 if (sbi->s_version == MINIX_V3)
422 ((minix3_dirent *)de)->inode = inode->i_ino;
423 else
424 de->inode = inode->i_ino;
425 dir_commit_chunk(folio, pos, sbi->s_dirsize);
426 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
427 mark_inode_dirty(dir);
428 return minix_handle_dirsync(dir);
429}
430
431struct minix_dir_entry *minix_dotdot(struct inode *dir, struct folio **foliop)
432{
433 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
434 struct minix_dir_entry *de = dir_get_folio(dir, 0, foliop);
435
436 if (!IS_ERR(de))
437 return minix_next_entry(de, sbi);
438 return NULL;
439}
440
441ino_t minix_inode_by_name(struct dentry *dentry)
442{
443 struct folio *folio;
444 struct minix_dir_entry *de = minix_find_entry(dentry, &folio);
445 ino_t res = 0;
446
447 if (de) {
448 struct inode *inode = folio->mapping->host;
449 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
450
451 if (sbi->s_version == MINIX_V3)
452 res = ((minix3_dirent *) de)->inode;
453 else
454 res = de->inode;
455 folio_release_kmap(folio, de);
456 }
457 return res;
458}