1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext2/namei.c
4 *
5 * Rewrite to pagecache. Almost all code had been changed, so blame me
6 * if the things go wrong. Please, send bug reports to
7 * viro@parcelfarce.linux.theplanet.co.uk
8 *
9 * Stuff here is basically a glue between the VFS and generic UNIXish
10 * filesystem that keeps everything in pagecache. All knowledge of the
11 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
12 * and it's easier to debug that way. In principle we might want to
13 * generalize that a bit and turn it into a library. Or not.
14 *
15 * The only non-static object here is ext2_dir_inode_operations.
16 *
17 * TODO: get rid of kmap() use, add readahead.
18 *
19 * Copyright (C) 1992, 1993, 1994, 1995
20 * Remy Card (card@masi.ibp.fr)
21 * Laboratoire MASI - Institut Blaise Pascal
22 * Universite Pierre et Marie Curie (Paris VI)
23 *
24 * from
25 *
26 * linux/fs/minix/namei.c
27 *
28 * Copyright (C) 1991, 1992 Linus Torvalds
29 *
30 * Big-endian to little-endian byte-swapping/bitmaps by
31 * David S. Miller (davem@caip.rutgers.edu), 1995
32 */
33
34 #include <linux/pagemap.h>
35 #include <linux/quotaops.h>
36 #include "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39
40 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
41 {
42 int err = ext2_add_link(dentry, inode);
43 if (!err) {
44 d_instantiate_new(dentry, inode);
45 return 0;
46 }
47 inode_dec_link_count(inode);
48 discard_new_inode(inode);
49 return err;
50 }
51
52 /*
53 * Methods themselves.
54 */
55
56 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
57 {
58 struct inode * inode;
59 ino_t ino;
60 int res;
61
62 if (dentry->d_name.len > EXT2_NAME_LEN)
63 return ERR_PTR(-ENAMETOOLONG);
64
65 res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
66 if (res) {
67 if (res != -ENOENT)
68 return ERR_PTR(res);
69 inode = NULL;
70 } else {
71 inode = ext2_iget(dir->i_sb, ino);
72 if (inode == ERR_PTR(-ESTALE)) {
73 ext2_error(dir->i_sb, __func__,
74 "deleted inode referenced: %lu",
75 (unsigned long) ino);
76 return ERR_PTR(-EIO);
77 }
78 }
79 return d_splice_alias(inode, dentry);
80 }
81
82 struct dentry *ext2_get_parent(struct dentry *child)
83 {
84 ino_t ino;
85 int res;
86
87 res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
88 if (res)
89 return ERR_PTR(res);
90
91 return d_obtain_alias(ext2_iget(child->d_sb, ino));
92 }
93
94 /*
95 * By the time this is called, we already have created
96 * the directory cache entry for the new file, but it
97 * is so far negative - it has no inode.
98 *
99 * If the create succeeds, we fill in the inode information
100 * with d_instantiate().
101 */
102 static int ext2_create (struct mnt_idmap * idmap,
103 struct inode * dir, struct dentry * dentry,
104 umode_t mode, bool excl)
105 {
106 struct inode *inode;
107 int err;
108
109 err = dquot_initialize(dir);
110 if (err)
111 return err;
112
113 inode = ext2_new_inode(dir, mode, &dentry->d_name);
114 if (IS_ERR(inode))
115 return PTR_ERR(inode);
116
117 ext2_set_file_ops(inode);
118 mark_inode_dirty(inode);
119 return ext2_add_nondir(dentry, inode);
120 }
121
122 static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
123 struct file *file, umode_t mode)
124 {
125 struct inode *inode = ext2_new_inode(dir, mode, NULL);
126 if (IS_ERR(inode))
127 return PTR_ERR(inode);
128
129 ext2_set_file_ops(inode);
130 mark_inode_dirty(inode);
131 d_tmpfile(file, inode);
132 unlock_new_inode(inode);
133 return finish_open_simple(file, 0);
134 }
135
136 static int ext2_mknod (struct mnt_idmap * idmap, struct inode * dir,
137 struct dentry *dentry, umode_t mode, dev_t rdev)
138 {
139 struct inode * inode;
140 int err;
141
142 err = dquot_initialize(dir);
143 if (err)
144 return err;
145
146 inode = ext2_new_inode (dir, mode, &dentry->d_name);
147 err = PTR_ERR(inode);
148 if (!IS_ERR(inode)) {
149 init_special_inode(inode, inode->i_mode, rdev);
150 inode->i_op = &ext2_special_inode_operations;
151 mark_inode_dirty(inode);
152 err = ext2_add_nondir(dentry, inode);
153 }
154 return err;
155 }
156
157 static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir,
158 struct dentry * dentry, const char * symname)
159 {
160 struct super_block * sb = dir->i_sb;
161 int err = -ENAMETOOLONG;
162 unsigned l = strlen(symname)+1;
163 struct inode * inode;
164
165 if (l > sb->s_blocksize)
166 goto out;
167
168 err = dquot_initialize(dir);
169 if (err)
170 goto out;
171
172 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
173 err = PTR_ERR(inode);
174 if (IS_ERR(inode))
175 goto out;
176
177 if (l > sizeof (EXT2_I(inode)->i_data)) {
178 /* slow symlink */
179 inode->i_op = &ext2_symlink_inode_operations;
180 inode_nohighmem(inode);
181 inode->i_mapping->a_ops = &ext2_aops;
182 err = page_symlink(inode, symname, l);
183 if (err)
184 goto out_fail;
185 } else {
186 /* fast symlink */
187 inode->i_op = &ext2_fast_symlink_inode_operations;
188 inode->i_link = (char*)EXT2_I(inode)->i_data;
189 memcpy(inode->i_link, symname, l);
190 inode->i_size = l-1;
191 }
192 mark_inode_dirty(inode);
193
194 err = ext2_add_nondir(dentry, inode);
195 out:
196 return err;
197
198 out_fail:
199 inode_dec_link_count(inode);
200 discard_new_inode(inode);
201 goto out;
202 }
203
204 static int ext2_link (struct dentry * old_dentry, struct inode * dir,
205 struct dentry *dentry)
206 {
207 struct inode *inode = d_inode(old_dentry);
208 int err;
209
210 err = dquot_initialize(dir);
211 if (err)
212 return err;
213
214 inode_set_ctime_current(inode);
215 inode_inc_link_count(inode);
216 ihold(inode);
217
218 err = ext2_add_link(dentry, inode);
219 if (!err) {
220 d_instantiate(dentry, inode);
221 return 0;
222 }
223 inode_dec_link_count(inode);
224 iput(inode);
225 return err;
226 }
227
228 static int ext2_mkdir(struct mnt_idmap * idmap,
229 struct inode * dir, struct dentry * dentry, umode_t mode)
230 {
231 struct inode * inode;
232 int err;
233
234 err = dquot_initialize(dir);
235 if (err)
236 return err;
237
238 inode_inc_link_count(dir);
239
240 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
241 err = PTR_ERR(inode);
242 if (IS_ERR(inode))
243 goto out_dir;
244
245 inode->i_op = &ext2_dir_inode_operations;
246 inode->i_fop = &ext2_dir_operations;
247 inode->i_mapping->a_ops = &ext2_aops;
248
249 inode_inc_link_count(inode);
250
251 err = ext2_make_empty(inode, dir);
252 if (err)
253 goto out_fail;
254
255 err = ext2_add_link(dentry, inode);
256 if (err)
257 goto out_fail;
258
259 d_instantiate_new(dentry, inode);
260 out:
261 return err;
262
263 out_fail:
264 inode_dec_link_count(inode);
265 inode_dec_link_count(inode);
266 discard_new_inode(inode);
267 out_dir:
268 inode_dec_link_count(dir);
269 goto out;
270 }
271
272 static int ext2_unlink(struct inode *dir, struct dentry *dentry)
273 {
274 struct inode *inode = d_inode(dentry);
275 struct ext2_dir_entry_2 *de;
276 struct folio *folio;
277 int err;
278
279 err = dquot_initialize(dir);
280 if (err)
281 goto out;
282
283 de = ext2_find_entry(dir, &dentry->d_name, &folio);
284 if (IS_ERR(de)) {
285 err = PTR_ERR(de);
286 goto out;
287 }
288
289 err = ext2_delete_entry(de, folio);
290 folio_release_kmap(folio, de);
291 if (err)
292 goto out;
293
294 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
295 inode_dec_link_count(inode);
296 err = 0;
297 out:
298 return err;
299 }
300
301 static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
302 {
303 struct inode * inode = d_inode(dentry);
304 int err = -ENOTEMPTY;
305
306 if (ext2_empty_dir(inode)) {
307 err = ext2_unlink(dir, dentry);
308 if (!err) {
309 inode->i_size = 0;
310 inode_dec_link_count(inode);
311 inode_dec_link_count(dir);
312 }
313 }
314 return err;
315 }
316
317 static int ext2_rename (struct mnt_idmap * idmap,
318 struct inode * old_dir, struct dentry * old_dentry,
319 struct inode * new_dir, struct dentry * new_dentry,
320 unsigned int flags)
321 {
322 struct inode * old_inode = d_inode(old_dentry);
323 struct inode * new_inode = d_inode(new_dentry);
324 struct folio *dir_folio = NULL;
325 struct ext2_dir_entry_2 * dir_de = NULL;
326 struct folio * old_folio;
327 struct ext2_dir_entry_2 * old_de;
328 bool old_is_dir = S_ISDIR(old_inode->i_mode);
329 int err;
330
331 if (flags & ~RENAME_NOREPLACE)
332 return -EINVAL;
333
334 err = dquot_initialize(old_dir);
335 if (err)
336 return err;
337
338 err = dquot_initialize(new_dir);
339 if (err)
340 return err;
341
342 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_folio);
343 if (IS_ERR(old_de))
344 return PTR_ERR(old_de);
345
346 if (old_is_dir && old_dir != new_dir) {
347 err = -EIO;
348 dir_de = ext2_dotdot(old_inode, &dir_folio);
349 if (!dir_de)
350 goto out_old;
351 }
352
353 if (new_inode) {
354 struct folio *new_folio;
355 struct ext2_dir_entry_2 *new_de;
356
357 err = -ENOTEMPTY;
358 if (old_is_dir && !ext2_empty_dir(new_inode))
359 goto out_dir;
360
361 new_de = ext2_find_entry(new_dir, &new_dentry->d_name,
362 &new_folio);
363 if (IS_ERR(new_de)) {
364 err = PTR_ERR(new_de);
365 goto out_dir;
366 }
367 err = ext2_set_link(new_dir, new_de, new_folio, old_inode, true);
368 folio_release_kmap(new_folio, new_de);
369 if (err)
370 goto out_dir;
371 inode_set_ctime_current(new_inode);
372 if (old_is_dir)
373 drop_nlink(new_inode);
374 inode_dec_link_count(new_inode);
375 } else {
376 err = ext2_add_link(new_dentry, old_inode);
377 if (err)
378 goto out_dir;
379 if (old_is_dir)
380 inode_inc_link_count(new_dir);
381 }
382
383 /*
384 * Like most other Unix systems, set the ctime for inodes on a
385 * rename.
386 */
387 inode_set_ctime_current(old_inode);
388 mark_inode_dirty(old_inode);
389
390 err = ext2_delete_entry(old_de, old_folio);
391 if (!err && old_is_dir) {
392 if (old_dir != new_dir)
393 err = ext2_set_link(old_inode, dir_de, dir_folio,
394 new_dir, false);
395
396 inode_dec_link_count(old_dir);
397 }
398 out_dir:
399 if (dir_de)
400 folio_release_kmap(dir_folio, dir_de);
401 out_old:
402 folio_release_kmap(old_folio, old_de);
403 return err;
404 }
405
406 const struct inode_operations ext2_dir_inode_operations = {
407 .create = ext2_create,
408 .lookup = ext2_lookup,
409 .link = ext2_link,
410 .unlink = ext2_unlink,
411 .symlink = ext2_symlink,
412 .mkdir = ext2_mkdir,
413 .rmdir = ext2_rmdir,
414 .mknod = ext2_mknod,
415 .rename = ext2_rename,
416 .listxattr = ext2_listxattr,
417 .getattr = ext2_getattr,
418 .setattr = ext2_setattr,
419 .get_inode_acl = ext2_get_acl,
420 .set_acl = ext2_set_acl,
421 .tmpfile = ext2_tmpfile,
422 .fileattr_get = ext2_fileattr_get,
423 .fileattr_set = ext2_fileattr_set,
424 };
425
426 const struct inode_operations ext2_special_inode_operations = {
427 .listxattr = ext2_listxattr,
428 .getattr = ext2_getattr,
429 .setattr = ext2_setattr,
430 .get_inode_acl = ext2_get_acl,
431 .set_acl = ext2_set_acl,
432 };
433
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