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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
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>
Christoph Hellwig907f4552010-03-03 09:05:06 -050035#include <linux/quotaops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include "ext2.h"
37#include "xattr.h"
38#include "acl.h"
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
41{
42 int err = ext2_add_link(dentry, inode);
43 if (!err) {
Al Viro1e2e5472018-05-04 08:23:01 -040044 d_instantiate_new(dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 return 0;
46 }
Alexey Dobriyana513b032006-03-23 03:00:53 -080047 inode_dec_link_count(inode);
Al Viro2e5afe52018-05-16 18:29:56 -040048 discard_new_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 return err;
50}
51
52/*
53 * Methods themselves.
54 */
55
Al Viro00cd8dd2012-06-10 17:13:09 -040056static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057{
58 struct inode * inode;
zhangyi (F)a43850a2020-06-08 11:40:43 +080059 ino_t ino;
zhangyi (F)b4962092020-06-08 11:40:42 +080060 int res;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62 if (dentry->d_name.len > EXT2_NAME_LEN)
63 return ERR_PTR(-ENAMETOOLONG);
64
zhangyi (F)b4962092020-06-08 11:40:42 +080065 res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
zhangyi (F)a43850a2020-06-08 11:40:43 +080066 if (res) {
67 if (res != -ENOENT)
68 return ERR_PTR(res);
69 inode = NULL;
70 } else {
David Howells52fcf702008-02-07 00:15:35 -080071 inode = ext2_iget(dir->i_sb, ino);
Al Viroa9049372011-07-08 21:20:11 -040072 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);
Bryan Donlan4d6c13f2009-06-30 11:41:24 -070077 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 }
Pekka Enberg082a05c2006-01-14 13:21:07 -080079 return d_splice_alias(inode, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080}
81
82struct dentry *ext2_get_parent(struct dentry *child)
83{
Linus Torvalds26fe5752012-05-10 13:14:12 -070084 struct qstr dotdot = QSTR_INIT("..", 2);
zhangyi (F)a43850a2020-06-08 11:40:43 +080085 ino_t ino;
zhangyi (F)b4962092020-06-08 11:40:42 +080086 int res;
87
88 res = ext2_inode_by_name(d_inode(child), &dotdot, &ino);
89 if (res)
90 return ERR_PTR(res);
zhangyi (F)a43850a2020-06-08 11:40:43 +080091
Al Virofc640052016-04-10 01:33:30 -040092 return d_obtain_alias(ext2_iget(child->d_sb, ino));
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
95/*
96 * By the time this is called, we already have created
97 * the directory cache entry for the new file, but it
98 * is so far negative - it has no inode.
99 *
100 * If the create succeeds, we fill in the inode information
101 * with d_instantiate().
102 */
Christian Brauner549c7292021-01-21 14:19:43 +0100103static int ext2_create (struct user_namespace * mnt_userns,
104 struct inode * dir, struct dentry * dentry,
105 umode_t mode, bool excl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106{
Christoph Hellwig907f4552010-03-03 09:05:06 -0500107 struct inode *inode;
Jan Karac2edb302015-06-29 16:08:45 +0200108 int err;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500109
Jan Karac2edb302015-06-29 16:08:45 +0200110 err = dquot_initialize(dir);
111 if (err)
112 return err;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500113
Eric Paris2a7dba32011-02-01 11:05:39 -0500114 inode = ext2_new_inode(dir, mode, &dentry->d_name);
Christoph Hellwig907f4552010-03-03 09:05:06 -0500115 if (IS_ERR(inode))
116 return PTR_ERR(inode);
117
Dan Williamsfb094c92017-12-21 12:25:11 -0800118 ext2_set_file_ops(inode);
Christoph Hellwig907f4552010-03-03 09:05:06 -0500119 mark_inode_dirty(inode);
120 return ext2_add_nondir(dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
Christian Brauner549c7292021-01-21 14:19:43 +0100123static int ext2_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
124 struct dentry *dentry, umode_t mode)
Al Viro60545d02013-06-07 01:20:27 -0400125{
126 struct inode *inode = ext2_new_inode(dir, mode, NULL);
127 if (IS_ERR(inode))
128 return PTR_ERR(inode);
129
Dan Williamsfb094c92017-12-21 12:25:11 -0800130 ext2_set_file_ops(inode);
Al Viro60545d02013-06-07 01:20:27 -0400131 mark_inode_dirty(inode);
132 d_tmpfile(dentry, inode);
133 unlock_new_inode(inode);
134 return 0;
135}
136
Christian Brauner549c7292021-01-21 14:19:43 +0100137static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir,
138 struct dentry *dentry, umode_t mode, dev_t rdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
140 struct inode * inode;
141 int err;
142
Jan Karac2edb302015-06-29 16:08:45 +0200143 err = dquot_initialize(dir);
144 if (err)
145 return err;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500146
Eric Paris2a7dba32011-02-01 11:05:39 -0500147 inode = ext2_new_inode (dir, mode, &dentry->d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 err = PTR_ERR(inode);
149 if (!IS_ERR(inode)) {
150 init_special_inode(inode, inode->i_mode, rdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 inode->i_op = &ext2_special_inode_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 mark_inode_dirty(inode);
153 err = ext2_add_nondir(dentry, inode);
154 }
155 return err;
156}
157
Christian Brauner549c7292021-01-21 14:19:43 +0100158static int ext2_symlink (struct user_namespace * mnt_userns, struct inode * dir,
159 struct dentry * dentry, const char * symname)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160{
161 struct super_block * sb = dir->i_sb;
162 int err = -ENAMETOOLONG;
163 unsigned l = strlen(symname)+1;
164 struct inode * inode;
165
166 if (l > sb->s_blocksize)
167 goto out;
168
Jan Karac2edb302015-06-29 16:08:45 +0200169 err = dquot_initialize(dir);
170 if (err)
171 goto out;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500172
Eric Paris2a7dba32011-02-01 11:05:39 -0500173 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 err = PTR_ERR(inode);
175 if (IS_ERR(inode))
176 goto out;
177
178 if (l > sizeof (EXT2_I(inode)->i_data)) {
179 /* slow symlink */
180 inode->i_op = &ext2_symlink_inode_operations;
Al Viro21fc61c2015-11-17 01:07:57 -0500181 inode_nohighmem(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 if (test_opt(inode->i_sb, NOBH))
183 inode->i_mapping->a_ops = &ext2_nobh_aops;
184 else
185 inode->i_mapping->a_ops = &ext2_aops;
186 err = page_symlink(inode, symname, l);
187 if (err)
188 goto out_fail;
189 } else {
190 /* fast symlink */
191 inode->i_op = &ext2_fast_symlink_inode_operations;
Al Virocbe0fa32015-05-02 10:02:46 -0400192 inode->i_link = (char*)EXT2_I(inode)->i_data;
193 memcpy(inode->i_link, symname, l);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 inode->i_size = l-1;
195 }
196 mark_inode_dirty(inode);
197
198 err = ext2_add_nondir(dentry, inode);
199out:
200 return err;
201
202out_fail:
Alexey Dobriyana513b032006-03-23 03:00:53 -0800203 inode_dec_link_count(inode);
Al Viro2e5afe52018-05-16 18:29:56 -0400204 discard_new_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 goto out;
206}
207
208static int ext2_link (struct dentry * old_dentry, struct inode * dir,
209 struct dentry *dentry)
210{
David Howells2b0143b2015-03-17 22:25:59 +0000211 struct inode *inode = d_inode(old_dentry);
Al Viro41080b52008-12-30 01:52:35 -0500212 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Jan Karac2edb302015-06-29 16:08:45 +0200214 err = dquot_initialize(dir);
215 if (err)
216 return err;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500217
Deepa Dinamani02027d42016-09-14 07:48:05 -0700218 inode->i_ctime = current_time(inode);
Alexey Dobriyana513b032006-03-23 03:00:53 -0800219 inode_inc_link_count(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400220 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Al Viro41080b52008-12-30 01:52:35 -0500222 err = ext2_add_link(dentry, inode);
223 if (!err) {
224 d_instantiate(dentry, inode);
225 return 0;
226 }
227 inode_dec_link_count(inode);
228 iput(inode);
229 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
Christian Brauner549c7292021-01-21 14:19:43 +0100232static int ext2_mkdir(struct user_namespace * mnt_userns,
233 struct inode * dir, struct dentry * dentry, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
235 struct inode * inode;
Al Viro8de52772012-02-06 12:45:27 -0500236 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237
Jan Karac2edb302015-06-29 16:08:45 +0200238 err = dquot_initialize(dir);
239 if (err)
240 return err;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500241
Alexey Dobriyana513b032006-03-23 03:00:53 -0800242 inode_inc_link_count(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
Eric Paris2a7dba32011-02-01 11:05:39 -0500244 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 err = PTR_ERR(inode);
246 if (IS_ERR(inode))
247 goto out_dir;
248
249 inode->i_op = &ext2_dir_inode_operations;
250 inode->i_fop = &ext2_dir_operations;
251 if (test_opt(inode->i_sb, NOBH))
252 inode->i_mapping->a_ops = &ext2_nobh_aops;
253 else
254 inode->i_mapping->a_ops = &ext2_aops;
255
Alexey Dobriyana513b032006-03-23 03:00:53 -0800256 inode_inc_link_count(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 err = ext2_make_empty(inode, dir);
259 if (err)
260 goto out_fail;
261
262 err = ext2_add_link(dentry, inode);
263 if (err)
264 goto out_fail;
265
Al Viro1e2e5472018-05-04 08:23:01 -0400266 d_instantiate_new(dentry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267out:
268 return err;
269
270out_fail:
Alexey Dobriyana513b032006-03-23 03:00:53 -0800271 inode_dec_link_count(inode);
272 inode_dec_link_count(inode);
Al Viro2e5afe52018-05-16 18:29:56 -0400273 discard_new_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274out_dir:
Alexey Dobriyana513b032006-03-23 03:00:53 -0800275 inode_dec_link_count(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 goto out;
277}
278
279static int ext2_unlink(struct inode * dir, struct dentry *dentry)
280{
David Howells2b0143b2015-03-17 22:25:59 +0000281 struct inode * inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 struct ext2_dir_entry_2 * de;
283 struct page * page;
Jan Karac2edb302015-06-29 16:08:45 +0200284 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285
Jan Karac2edb302015-06-29 16:08:45 +0200286 err = dquot_initialize(dir);
287 if (err)
288 goto out;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500289
zhangyi (F)b4962092020-06-08 11:40:42 +0800290 de = ext2_find_entry(dir, &dentry->d_name, &page);
291 if (IS_ERR(de)) {
292 err = PTR_ERR(de);
293 goto out;
294 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
296 err = ext2_delete_entry (de, page);
297 if (err)
298 goto out;
299
300 inode->i_ctime = dir->i_ctime;
Alexey Dobriyana513b032006-03-23 03:00:53 -0800301 inode_dec_link_count(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 err = 0;
303out:
304 return err;
305}
306
307static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
308{
David Howells2b0143b2015-03-17 22:25:59 +0000309 struct inode * inode = d_inode(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 int err = -ENOTEMPTY;
311
312 if (ext2_empty_dir(inode)) {
313 err = ext2_unlink(dir, dentry);
314 if (!err) {
315 inode->i_size = 0;
Alexey Dobriyana513b032006-03-23 03:00:53 -0800316 inode_dec_link_count(inode);
317 inode_dec_link_count(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 }
319 }
320 return err;
321}
322
Christian Brauner549c7292021-01-21 14:19:43 +0100323static int ext2_rename (struct user_namespace * mnt_userns,
324 struct inode * old_dir, struct dentry * old_dentry,
325 struct inode * new_dir, struct dentry * new_dentry,
Miklos Szeredif03b8ad2016-09-27 11:03:57 +0200326 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327{
David Howells2b0143b2015-03-17 22:25:59 +0000328 struct inode * old_inode = d_inode(old_dentry);
329 struct inode * new_inode = d_inode(new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 struct page * dir_page = NULL;
331 struct ext2_dir_entry_2 * dir_de = NULL;
332 struct page * old_page;
333 struct ext2_dir_entry_2 * old_de;
Jan Karac2edb302015-06-29 16:08:45 +0200334 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
Miklos Szeredif03b8ad2016-09-27 11:03:57 +0200336 if (flags & ~RENAME_NOREPLACE)
337 return -EINVAL;
338
Jan Karac2edb302015-06-29 16:08:45 +0200339 err = dquot_initialize(old_dir);
340 if (err)
341 goto out;
342
343 err = dquot_initialize(new_dir);
344 if (err)
345 goto out;
Christoph Hellwig907f4552010-03-03 09:05:06 -0500346
zhangyi (F)b4962092020-06-08 11:40:42 +0800347 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page);
348 if (IS_ERR(old_de)) {
349 err = PTR_ERR(old_de);
350 goto out;
351 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352
353 if (S_ISDIR(old_inode->i_mode)) {
354 err = -EIO;
355 dir_de = ext2_dotdot(old_inode, &dir_page);
356 if (!dir_de)
357 goto out_old;
358 }
359
360 if (new_inode) {
361 struct page *new_page;
362 struct ext2_dir_entry_2 *new_de;
363
364 err = -ENOTEMPTY;
365 if (dir_de && !ext2_empty_dir (new_inode))
366 goto out_dir;
367
zhangyi (F)b4962092020-06-08 11:40:42 +0800368 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, &new_page);
369 if (IS_ERR(new_de)) {
370 err = PTR_ERR(new_de);
371 goto out_dir;
372 }
Jan Kara39fe7552009-06-17 16:26:20 -0700373 ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
Deepa Dinamani02027d42016-09-14 07:48:05 -0700374 new_inode->i_ctime = current_time(new_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 if (dir_de)
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700376 drop_nlink(new_inode);
Alexey Dobriyana513b032006-03-23 03:00:53 -0800377 inode_dec_link_count(new_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 err = ext2_add_link(new_dentry, old_inode);
Josh Hunte8a80c62011-02-24 11:48:22 +0100380 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 goto out_dir;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 if (dir_de)
Alexey Dobriyana513b032006-03-23 03:00:53 -0800383 inode_inc_link_count(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
385
386 /*
387 * Like most other Unix systems, set the ctime for inodes on a
388 * rename.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 */
Deepa Dinamani02027d42016-09-14 07:48:05 -0700390 old_inode->i_ctime = current_time(old_inode);
Josh Hunte8a80c62011-02-24 11:48:22 +0100391 mark_inode_dirty(old_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392
393 ext2_delete_entry (old_de, old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
395 if (dir_de) {
Jan Kara39fe7552009-06-17 16:26:20 -0700396 if (old_dir != new_dir)
397 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
Ira Weinya6fbd0a2020-11-12 09:42:44 -0800398 else
399 ext2_put_page(dir_page);
Alexey Dobriyana513b032006-03-23 03:00:53 -0800400 inode_dec_link_count(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 }
402 return 0;
403
404
405out_dir:
Ira Weinya6fbd0a2020-11-12 09:42:44 -0800406 if (dir_de)
407 ext2_put_page(dir_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408out_old:
Ira Weinya6fbd0a2020-11-12 09:42:44 -0800409 ext2_put_page(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410out:
411 return err;
412}
413
Arjan van de Ven754661f2007-02-12 00:55:38 -0800414const struct inode_operations ext2_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 .create = ext2_create,
416 .lookup = ext2_lookup,
417 .link = ext2_link,
418 .unlink = ext2_unlink,
419 .symlink = ext2_symlink,
420 .mkdir = ext2_mkdir,
421 .rmdir = ext2_rmdir,
422 .mknod = ext2_mknod,
423 .rename = ext2_rename,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 .listxattr = ext2_listxattr,
yangerkun93bc4202019-02-18 09:07:02 +0800425 .getattr = ext2_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 .setattr = ext2_setattr,
Christoph Hellwig4e34e712011-07-23 17:37:31 +0200427 .get_acl = ext2_get_acl,
Christoph Hellwig64e178a2013-12-20 05:16:44 -0800428 .set_acl = ext2_set_acl,
Al Viro60545d02013-06-07 01:20:27 -0400429 .tmpfile = ext2_tmpfile,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430};
431
Arjan van de Ven754661f2007-02-12 00:55:38 -0800432const struct inode_operations ext2_special_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 .listxattr = ext2_listxattr,
yangerkun93bc4202019-02-18 09:07:02 +0800434 .getattr = ext2_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 .setattr = ext2_setattr,
Christoph Hellwig4e34e712011-07-23 17:37:31 +0200436 .get_acl = ext2_get_acl,
Christoph Hellwig64e178a2013-12-20 05:16:44 -0800437 .set_acl = ext2_set_acl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438};