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Miklos Szeredie9be9d52014-10-24 00:14:38 +02001/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/namei.h>
12#include <linux/xattr.h>
13#include <linux/security.h>
14#include <linux/cred.h>
Miklos Szeredi38b25692016-09-01 11:11:59 +020015#include <linux/posix_acl.h>
16#include <linux/posix_acl_xattr.h>
Miklos Szeredie9be9d52014-10-24 00:14:38 +020017#include "overlayfs.h"
18
19void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
20{
21 int err;
22
23 dget(wdentry);
David Howellse36cb0b2015-01-29 12:02:35 +000024 if (d_is_dir(wdentry))
Miklos Szeredie9be9d52014-10-24 00:14:38 +020025 err = ovl_do_rmdir(wdir, wdentry);
26 else
27 err = ovl_do_unlink(wdir, wdentry);
28 dput(wdentry);
29
30 if (err) {
31 pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
32 wdentry, err);
33 }
34}
35
36struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
37{
38 struct dentry *temp;
39 char name[20];
40
41 snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry);
42
43 temp = lookup_one_len(name, workdir, strlen(name));
44 if (!IS_ERR(temp) && temp->d_inode) {
45 pr_err("overlayfs: workdir/%s already exists\n", name);
46 dput(temp);
47 temp = ERR_PTR(-EIO);
48 }
49
50 return temp;
51}
52
53/* caller holds i_mutex on workdir */
54static struct dentry *ovl_whiteout(struct dentry *workdir,
55 struct dentry *dentry)
56{
57 int err;
58 struct dentry *whiteout;
59 struct inode *wdir = workdir->d_inode;
60
61 whiteout = ovl_lookup_temp(workdir, dentry);
62 if (IS_ERR(whiteout))
63 return whiteout;
64
65 err = ovl_do_whiteout(wdir, whiteout);
66 if (err) {
67 dput(whiteout);
68 whiteout = ERR_PTR(err);
69 }
70
71 return whiteout;
72}
73
74int ovl_create_real(struct inode *dir, struct dentry *newdentry,
75 struct kstat *stat, const char *link,
76 struct dentry *hardlink, bool debug)
77{
78 int err;
79
80 if (newdentry->d_inode)
81 return -ESTALE;
82
83 if (hardlink) {
84 err = ovl_do_link(hardlink, dir, newdentry, debug);
85 } else {
86 switch (stat->mode & S_IFMT) {
87 case S_IFREG:
88 err = ovl_do_create(dir, newdentry, stat->mode, debug);
89 break;
90
91 case S_IFDIR:
92 err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
93 break;
94
95 case S_IFCHR:
96 case S_IFBLK:
97 case S_IFIFO:
98 case S_IFSOCK:
99 err = ovl_do_mknod(dir, newdentry,
100 stat->mode, stat->rdev, debug);
101 break;
102
103 case S_IFLNK:
104 err = ovl_do_symlink(dir, newdentry, link, debug);
105 break;
106
107 default:
108 err = -EPERM;
109 }
110 }
111 if (!err && WARN_ON(!newdentry->d_inode)) {
112 /*
113 * Not quite sure if non-instantiated dentry is legal or not.
114 * VFS doesn't seem to care so check and warn here.
115 */
116 err = -ENOENT;
117 }
118 return err;
119}
120
121static int ovl_set_opaque(struct dentry *upperdentry)
122{
hujianyangcead89b2014-11-24 18:25:21 +0800123 return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200124}
125
126static void ovl_remove_opaque(struct dentry *upperdentry)
127{
128 int err;
129
hujianyangcead89b2014-11-24 18:25:21 +0800130 err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200131 if (err) {
132 pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
133 upperdentry->d_name.name, err);
134 }
135}
136
137static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
138 struct kstat *stat)
139{
140 int err;
141 enum ovl_path_type type;
142 struct path realpath;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400143 const struct cred *old_cred;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200144
145 type = ovl_path_real(dentry, &realpath);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400146 old_cred = ovl_override_creds(dentry->d_sb);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200147 err = vfs_getattr(&realpath, stat);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400148 revert_creds(old_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200149 if (err)
150 return err;
151
152 stat->dev = dentry->d_sb->s_dev;
153 stat->ino = dentry->d_inode->i_ino;
154
155 /*
156 * It's probably not worth it to count subdirs to get the
157 * correct link count. nlink=1 seems to pacify 'find' and
158 * other utilities.
159 */
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100160 if (OVL_TYPE_MERGE(type))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200161 stat->nlink = 1;
162
163 return 0;
164}
165
Vivek Goyal72e48482016-06-16 10:09:14 -0400166/* Common operations required to be done after creation of file on upper */
167static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200168 struct dentry *newdentry, bool hardlink)
Vivek Goyal72e48482016-06-16 10:09:14 -0400169{
170 ovl_dentry_version_inc(dentry->d_parent);
171 ovl_dentry_update(dentry, newdentry);
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200172 if (!hardlink) {
173 ovl_inode_update(inode, d_inode(newdentry));
174 ovl_copyattr(newdentry->d_inode, inode);
175 } else {
176 WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
177 inc_nlink(inode);
178 }
Vivek Goyal72e48482016-06-16 10:09:14 -0400179 d_instantiate(dentry, inode);
180}
181
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200182static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
183 struct kstat *stat, const char *link,
184 struct dentry *hardlink)
185{
186 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
187 struct inode *udir = upperdir->d_inode;
188 struct dentry *newdentry;
189 int err;
190
Miklos Szeredi38b25692016-09-01 11:11:59 +0200191 if (!hardlink && !IS_POSIXACL(udir))
192 stat->mode &= ~current_umask();
193
Al Viro59551022016-01-22 15:40:57 -0500194 inode_lock_nested(udir, I_MUTEX_PARENT);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200195 newdentry = lookup_one_len(dentry->d_name.name, upperdir,
196 dentry->d_name.len);
197 err = PTR_ERR(newdentry);
198 if (IS_ERR(newdentry))
199 goto out_unlock;
200 err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
201 if (err)
202 goto out_dput;
203
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200204 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200205 newdentry = NULL;
206out_dput:
207 dput(newdentry);
208out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500209 inode_unlock(udir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200210 return err;
211}
212
213static int ovl_lock_rename_workdir(struct dentry *workdir,
214 struct dentry *upperdir)
215{
216 /* Workdir should not be the same as upperdir */
217 if (workdir == upperdir)
218 goto err;
219
220 /* Workdir should not be subdir of upperdir and vice versa */
221 if (lock_rename(workdir, upperdir) != NULL)
222 goto err_unlock;
223
224 return 0;
225
226err_unlock:
227 unlock_rename(workdir, upperdir);
228err:
229 pr_err("overlayfs: failed to lock workdir+upperdir\n");
230 return -EIO;
231}
232
233static struct dentry *ovl_clear_empty(struct dentry *dentry,
234 struct list_head *list)
235{
236 struct dentry *workdir = ovl_workdir(dentry);
237 struct inode *wdir = workdir->d_inode;
238 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
239 struct inode *udir = upperdir->d_inode;
240 struct path upperpath;
241 struct dentry *upper;
242 struct dentry *opaquedir;
243 struct kstat stat;
244 int err;
245
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200246 if (WARN_ON(!workdir))
247 return ERR_PTR(-EROFS);
248
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200249 err = ovl_lock_rename_workdir(workdir, upperdir);
250 if (err)
251 goto out;
252
253 ovl_path_upper(dentry, &upperpath);
254 err = vfs_getattr(&upperpath, &stat);
255 if (err)
256 goto out_unlock;
257
258 err = -ESTALE;
259 if (!S_ISDIR(stat.mode))
260 goto out_unlock;
261 upper = upperpath.dentry;
262 if (upper->d_parent->d_inode != udir)
263 goto out_unlock;
264
265 opaquedir = ovl_lookup_temp(workdir, dentry);
266 err = PTR_ERR(opaquedir);
267 if (IS_ERR(opaquedir))
268 goto out_unlock;
269
270 err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
271 if (err)
272 goto out_dput;
273
274 err = ovl_copy_xattr(upper, opaquedir);
275 if (err)
276 goto out_cleanup;
277
278 err = ovl_set_opaque(opaquedir);
279 if (err)
280 goto out_cleanup;
281
Al Viro59551022016-01-22 15:40:57 -0500282 inode_lock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200283 err = ovl_set_attr(opaquedir, &stat);
Al Viro59551022016-01-22 15:40:57 -0500284 inode_unlock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200285 if (err)
286 goto out_cleanup;
287
288 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
289 if (err)
290 goto out_cleanup;
291
292 ovl_cleanup_whiteouts(upper, list);
293 ovl_cleanup(wdir, upper);
294 unlock_rename(workdir, upperdir);
295
296 /* dentry's upper doesn't match now, get rid of it */
297 d_drop(dentry);
298
299 return opaquedir;
300
301out_cleanup:
302 ovl_cleanup(wdir, opaquedir);
303out_dput:
304 dput(opaquedir);
305out_unlock:
306 unlock_rename(workdir, upperdir);
307out:
308 return ERR_PTR(err);
309}
310
Miklos Szeredia105d682014-11-20 16:39:59 +0100311static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200312{
313 int err;
314 struct dentry *ret = NULL;
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200315 enum ovl_path_type type = ovl_path_type(dentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200316 LIST_HEAD(list);
317
318 err = ovl_check_empty_dir(dentry, &list);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200319 if (err) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200320 ret = ERR_PTR(err);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200321 goto out_free;
Miklos Szeredia105d682014-11-20 16:39:59 +0100322 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200323
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200324 /*
325 * When removing an empty opaque directory, then it makes no sense to
326 * replace it with an exact replica of itself.
327 *
328 * If no upperdentry then skip clearing whiteouts.
329 *
330 * Can race with copy-up, since we don't hold the upperdir mutex.
331 * Doesn't matter, since copy-up can't create a non-empty directory
332 * from an empty one.
333 */
334 if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
335 ret = ovl_clear_empty(dentry, &list);
336
337out_free:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200338 ovl_cache_free(&list);
339
340 return ret;
341}
342
Miklos Szeredi38b25692016-09-01 11:11:59 +0200343static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
344 const struct posix_acl *acl)
345{
346 void *buffer;
347 size_t size;
348 int err;
349
350 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
351 return 0;
352
353 size = posix_acl_to_xattr(NULL, acl, NULL, 0);
354 buffer = kmalloc(size, GFP_KERNEL);
355 if (!buffer)
356 return -ENOMEM;
357
358 size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
359 err = size;
360 if (err < 0)
361 goto out_free;
362
363 err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
364out_free:
365 kfree(buffer);
366 return err;
367}
368
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200369static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
370 struct kstat *stat, const char *link,
371 struct dentry *hardlink)
372{
373 struct dentry *workdir = ovl_workdir(dentry);
374 struct inode *wdir = workdir->d_inode;
375 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
376 struct inode *udir = upperdir->d_inode;
377 struct dentry *upper;
378 struct dentry *newdentry;
379 int err;
Miklos Szeredi38b25692016-09-01 11:11:59 +0200380 struct posix_acl *acl, *default_acl;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200381
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200382 if (WARN_ON(!workdir))
383 return -EROFS;
384
Miklos Szeredi38b25692016-09-01 11:11:59 +0200385 if (!hardlink) {
386 err = posix_acl_create(dentry->d_parent->d_inode,
387 &stat->mode, &default_acl, &acl);
388 if (err)
389 return err;
390 }
391
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200392 err = ovl_lock_rename_workdir(workdir, upperdir);
393 if (err)
394 goto out;
395
396 newdentry = ovl_lookup_temp(workdir, dentry);
397 err = PTR_ERR(newdentry);
398 if (IS_ERR(newdentry))
399 goto out_unlock;
400
401 upper = lookup_one_len(dentry->d_name.name, upperdir,
402 dentry->d_name.len);
403 err = PTR_ERR(upper);
404 if (IS_ERR(upper))
405 goto out_dput;
406
407 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
408 if (err)
409 goto out_dput2;
410
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200411 /*
412 * mode could have been mutilated due to umask (e.g. sgid directory)
413 */
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200414 if (!hardlink &&
415 !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200416 struct iattr attr = {
417 .ia_valid = ATTR_MODE,
418 .ia_mode = stat->mode,
419 };
420 inode_lock(newdentry->d_inode);
421 err = notify_change(newdentry, &attr, NULL);
422 inode_unlock(newdentry->d_inode);
423 if (err)
424 goto out_cleanup;
425 }
Miklos Szeredi38b25692016-09-01 11:11:59 +0200426 if (!hardlink) {
427 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
428 acl);
429 if (err)
430 goto out_cleanup;
431
432 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
433 default_acl);
434 if (err)
435 goto out_cleanup;
436 }
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200437
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200438 if (!hardlink && S_ISDIR(stat->mode)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200439 err = ovl_set_opaque(newdentry);
440 if (err)
441 goto out_cleanup;
442
443 err = ovl_do_rename(wdir, newdentry, udir, upper,
444 RENAME_EXCHANGE);
445 if (err)
446 goto out_cleanup;
447
448 ovl_cleanup(wdir, upper);
449 } else {
450 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
451 if (err)
452 goto out_cleanup;
453 }
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200454 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200455 newdentry = NULL;
456out_dput2:
457 dput(upper);
458out_dput:
459 dput(newdentry);
460out_unlock:
461 unlock_rename(workdir, upperdir);
462out:
Miklos Szeredi38b25692016-09-01 11:11:59 +0200463 if (!hardlink) {
464 posix_acl_release(acl);
465 posix_acl_release(default_acl);
466 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200467 return err;
468
469out_cleanup:
470 ovl_cleanup(wdir, newdentry);
471 goto out_dput2;
472}
473
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200474static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
475 struct kstat *stat, const char *link,
476 struct dentry *hardlink)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200477{
478 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400479 const struct cred *old_cred;
480 struct cred *override_cred;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200481
482 err = ovl_copy_up(dentry->d_parent);
483 if (err)
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200484 return err;
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200485
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400486 old_cred = ovl_override_creds(dentry->d_sb);
487 err = -ENOMEM;
488 override_cred = prepare_creds();
489 if (override_cred) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200490 override_cred->fsuid = inode->i_uid;
491 override_cred->fsgid = inode->i_gid;
Vivek Goyal26026252016-07-13 10:44:52 -0400492 if (!hardlink) {
493 err = security_dentry_create_files_as(dentry,
494 stat->mode, &dentry->d_name, old_cred,
495 override_cred);
496 if (err) {
497 put_cred(override_cred);
498 goto out_revert_creds;
499 }
500 }
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400501 put_cred(override_creds(override_cred));
502 put_cred(override_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200503
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400504 if (!ovl_dentry_is_opaque(dentry))
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200505 err = ovl_create_upper(dentry, inode, stat, link,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400506 hardlink);
507 else
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200508 err = ovl_create_over_whiteout(dentry, inode, stat,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400509 link, hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200510 }
Vivek Goyal26026252016-07-13 10:44:52 -0400511out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400512 revert_creds(old_cred);
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200513 if (!err) {
514 struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
515
516 WARN_ON(inode->i_mode != realinode->i_mode);
517 WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
518 WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200519 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200520 return err;
521}
522
523static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
524 const char *link)
525{
526 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200527 struct inode *inode;
528 struct kstat stat = {
529 .rdev = rdev,
530 };
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200531
532 err = ovl_want_write(dentry);
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200533 if (err)
534 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200535
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200536 err = -ENOMEM;
537 inode = ovl_new_inode(dentry->d_sb, mode);
538 if (!inode)
539 goto out_drop_write;
540
541 inode_init_owner(inode, dentry->d_parent->d_inode, mode);
542 stat.mode = inode->i_mode;
543
544 err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
545 if (err)
546 iput(inode);
547
548out_drop_write:
549 ovl_drop_write(dentry);
550out:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200551 return err;
552}
553
554static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
555 bool excl)
556{
557 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
558}
559
560static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
561{
562 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
563}
564
565static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
566 dev_t rdev)
567{
568 /* Don't allow creation of "whiteout" on overlay */
569 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
570 return -EPERM;
571
572 return ovl_create_object(dentry, mode, rdev, NULL);
573}
574
575static int ovl_symlink(struct inode *dir, struct dentry *dentry,
576 const char *link)
577{
578 return ovl_create_object(dentry, S_IFLNK, 0, link);
579}
580
581static int ovl_link(struct dentry *old, struct inode *newdir,
582 struct dentry *new)
583{
584 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200585 struct inode *inode;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200586
587 err = ovl_want_write(old);
588 if (err)
589 goto out;
590
591 err = ovl_copy_up(old);
592 if (err)
593 goto out_drop_write;
594
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200595 inode = d_inode(old);
596 ihold(inode);
597
598 err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
599 if (err)
600 iput(inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200601
602out_drop_write:
603 ovl_drop_write(old);
604out:
605 return err;
606}
607
Miklos Szeredia105d682014-11-20 16:39:59 +0100608static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200609{
610 struct dentry *workdir = ovl_workdir(dentry);
611 struct inode *wdir = workdir->d_inode;
612 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
613 struct inode *udir = upperdir->d_inode;
614 struct dentry *whiteout;
615 struct dentry *upper;
616 struct dentry *opaquedir = NULL;
617 int err;
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700618 int flags = 0;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200619
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200620 if (WARN_ON(!workdir))
621 return -EROFS;
622
Miklos Szeredid377c5e2015-05-14 10:04:44 +0200623 if (is_dir) {
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200624 opaquedir = ovl_check_empty_and_clear(dentry);
625 err = PTR_ERR(opaquedir);
626 if (IS_ERR(opaquedir))
627 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200628 }
629
630 err = ovl_lock_rename_workdir(workdir, upperdir);
631 if (err)
632 goto out_dput;
633
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700634 upper = lookup_one_len(dentry->d_name.name, upperdir,
635 dentry->d_name.len);
636 err = PTR_ERR(upper);
637 if (IS_ERR(upper))
638 goto out_unlock;
639
640 err = -ESTALE;
641 if ((opaquedir && upper != opaquedir) ||
642 (!opaquedir && ovl_dentry_upper(dentry) &&
643 upper != ovl_dentry_upper(dentry))) {
644 goto out_dput_upper;
645 }
646
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200647 whiteout = ovl_whiteout(workdir, dentry);
648 err = PTR_ERR(whiteout);
649 if (IS_ERR(whiteout))
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700650 goto out_dput_upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200651
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700652 if (d_is_dir(upper))
653 flags = RENAME_EXCHANGE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200654
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700655 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
656 if (err)
657 goto kill_whiteout;
658 if (flags)
659 ovl_cleanup(wdir, upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200660
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200661 ovl_dentry_version_inc(dentry->d_parent);
662out_d_drop:
663 d_drop(dentry);
664 dput(whiteout);
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700665out_dput_upper:
666 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200667out_unlock:
668 unlock_rename(workdir, upperdir);
669out_dput:
670 dput(opaquedir);
671out:
672 return err;
673
674kill_whiteout:
675 ovl_cleanup(wdir, whiteout);
676 goto out_d_drop;
677}
678
679static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
680{
681 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
682 struct inode *dir = upperdir->d_inode;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100683 struct dentry *upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200684 int err;
685
Al Viro59551022016-01-22 15:40:57 -0500686 inode_lock_nested(dir, I_MUTEX_PARENT);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100687 upper = lookup_one_len(dentry->d_name.name, upperdir,
688 dentry->d_name.len);
689 err = PTR_ERR(upper);
690 if (IS_ERR(upper))
691 goto out_unlock;
692
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200693 err = -ESTALE;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100694 if (upper == ovl_dentry_upper(dentry)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200695 if (is_dir)
696 err = vfs_rmdir(dir, upper);
697 else
698 err = vfs_unlink(dir, upper, NULL);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200699 ovl_dentry_version_inc(dentry->d_parent);
700 }
Miklos Szeredi11f37102016-03-21 17:31:44 +0100701 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200702
703 /*
704 * Keeping this dentry hashed would mean having to release
705 * upperpath/lowerpath, which could only be done if we are the
706 * sole user of this dentry. Too tricky... Just unhash for
707 * now.
708 */
Rui Wangce9113b2016-01-08 23:09:59 +0800709 if (!err)
710 d_drop(dentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100711out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500712 inode_unlock(dir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200713
714 return err;
715}
716
717static inline int ovl_check_sticky(struct dentry *dentry)
718{
719 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
720 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
721
722 if (check_sticky(dir, inode))
723 return -EPERM;
724
725 return 0;
726}
727
728static int ovl_do_remove(struct dentry *dentry, bool is_dir)
729{
730 enum ovl_path_type type;
731 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400732 const struct cred *old_cred;
733
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200734
735 err = ovl_check_sticky(dentry);
736 if (err)
737 goto out;
738
739 err = ovl_want_write(dentry);
740 if (err)
741 goto out;
742
743 err = ovl_copy_up(dentry->d_parent);
744 if (err)
745 goto out_drop_write;
746
747 type = ovl_path_type(dentry);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400748
749 old_cred = ovl_override_creds(dentry->d_sb);
750 if (OVL_TYPE_PURE_UPPER(type))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200751 err = ovl_remove_upper(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400752 else
Miklos Szeredia105d682014-11-20 16:39:59 +0100753 err = ovl_remove_and_whiteout(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400754 revert_creds(old_cred);
Miklos Szeredidbc816d2016-07-29 12:05:24 +0200755 if (!err) {
756 if (is_dir)
757 clear_nlink(dentry->d_inode);
758 else
759 drop_nlink(dentry->d_inode);
760 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200761out_drop_write:
762 ovl_drop_write(dentry);
763out:
764 return err;
765}
766
767static int ovl_unlink(struct inode *dir, struct dentry *dentry)
768{
769 return ovl_do_remove(dentry, false);
770}
771
772static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
773{
774 return ovl_do_remove(dentry, true);
775}
776
777static int ovl_rename2(struct inode *olddir, struct dentry *old,
778 struct inode *newdir, struct dentry *new,
779 unsigned int flags)
780{
781 int err;
782 enum ovl_path_type old_type;
783 enum ovl_path_type new_type;
784 struct dentry *old_upperdir;
785 struct dentry *new_upperdir;
786 struct dentry *olddentry;
787 struct dentry *newdentry;
788 struct dentry *trap;
789 bool old_opaque;
790 bool new_opaque;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200791 bool cleanup_whiteout = false;
792 bool overwrite = !(flags & RENAME_EXCHANGE);
David Howellse36cb0b2015-01-29 12:02:35 +0000793 bool is_dir = d_is_dir(old);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200794 bool new_is_dir = false;
795 struct dentry *opaquedir = NULL;
796 const struct cred *old_cred = NULL;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200797
798 err = -EINVAL;
799 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
800 goto out;
801
802 flags &= ~RENAME_NOREPLACE;
803
804 err = ovl_check_sticky(old);
805 if (err)
806 goto out;
807
808 /* Don't copy up directory trees */
809 old_type = ovl_path_type(old);
810 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100811 if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200812 goto out;
813
814 if (new->d_inode) {
815 err = ovl_check_sticky(new);
816 if (err)
817 goto out;
818
David Howellse36cb0b2015-01-29 12:02:35 +0000819 if (d_is_dir(new))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200820 new_is_dir = true;
821
822 new_type = ovl_path_type(new);
823 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100824 if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200825 goto out;
826
827 err = 0;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100828 if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200829 if (ovl_dentry_lower(old)->d_inode ==
830 ovl_dentry_lower(new)->d_inode)
831 goto out;
832 }
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100833 if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200834 if (ovl_dentry_upper(old)->d_inode ==
835 ovl_dentry_upper(new)->d_inode)
836 goto out;
837 }
838 } else {
839 if (ovl_dentry_is_opaque(new))
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100840 new_type = __OVL_PATH_UPPER;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200841 else
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100842 new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200843 }
844
845 err = ovl_want_write(old);
846 if (err)
847 goto out;
848
849 err = ovl_copy_up(old);
850 if (err)
851 goto out_drop_write;
852
853 err = ovl_copy_up(new->d_parent);
854 if (err)
855 goto out_drop_write;
856 if (!overwrite) {
857 err = ovl_copy_up(new);
858 if (err)
859 goto out_drop_write;
860 }
861
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100862 old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
863 new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200864
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400865 old_cred = ovl_override_creds(old->d_sb);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200866
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100867 if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
Miklos Szeredia105d682014-11-20 16:39:59 +0100868 opaquedir = ovl_check_empty_and_clear(new);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200869 err = PTR_ERR(opaquedir);
870 if (IS_ERR(opaquedir)) {
871 opaquedir = NULL;
872 goto out_revert_creds;
873 }
874 }
875
876 if (overwrite) {
877 if (old_opaque) {
878 if (new->d_inode || !new_opaque) {
879 /* Whiteout source */
880 flags |= RENAME_WHITEOUT;
881 } else {
882 /* Switch whiteouts */
883 flags |= RENAME_EXCHANGE;
884 }
885 } else if (is_dir && !new->d_inode && new_opaque) {
886 flags |= RENAME_EXCHANGE;
887 cleanup_whiteout = true;
888 }
889 }
890
891 old_upperdir = ovl_dentry_upper(old->d_parent);
892 new_upperdir = ovl_dentry_upper(new->d_parent);
893
894 trap = lock_rename(new_upperdir, old_upperdir);
895
Miklos Szeredi11f37102016-03-21 17:31:44 +0100896
897 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
898 old->d_name.len);
899 err = PTR_ERR(olddentry);
900 if (IS_ERR(olddentry))
901 goto out_unlock;
902
903 err = -ESTALE;
904 if (olddentry != ovl_dentry_upper(old))
905 goto out_dput_old;
906
907 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
908 new->d_name.len);
909 err = PTR_ERR(newdentry);
910 if (IS_ERR(newdentry))
911 goto out_dput_old;
912
913 err = -ESTALE;
914 if (ovl_dentry_upper(new)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200915 if (opaquedir) {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100916 if (newdentry != opaquedir)
917 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200918 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100919 if (newdentry != ovl_dentry_upper(new))
920 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200921 }
922 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100923 if (!d_is_negative(newdentry) &&
924 (!new_opaque || !ovl_is_whiteout(newdentry)))
925 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200926 }
927
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200928 if (olddentry == trap)
929 goto out_dput;
930 if (newdentry == trap)
931 goto out_dput;
932
933 if (is_dir && !old_opaque && new_opaque) {
934 err = ovl_set_opaque(olddentry);
935 if (err)
936 goto out_dput;
937 }
938 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
939 err = ovl_set_opaque(newdentry);
940 if (err)
941 goto out_dput;
942 }
943
944 if (old_opaque || new_opaque) {
945 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
946 new_upperdir->d_inode, newdentry,
947 flags);
948 } else {
949 /* No debug for the plain case */
950 BUG_ON(flags & ~RENAME_EXCHANGE);
951 err = vfs_rename(old_upperdir->d_inode, olddentry,
952 new_upperdir->d_inode, newdentry,
953 NULL, flags);
954 }
955
956 if (err) {
957 if (is_dir && !old_opaque && new_opaque)
958 ovl_remove_opaque(olddentry);
959 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
960 ovl_remove_opaque(newdentry);
961 goto out_dput;
962 }
963
964 if (is_dir && old_opaque && !new_opaque)
965 ovl_remove_opaque(olddentry);
966 if (!overwrite && new_is_dir && !old_opaque && new_opaque)
967 ovl_remove_opaque(newdentry);
968
Konstantin Khlebnikov45d11732016-01-31 16:17:53 +0300969 /*
970 * Old dentry now lives in different location. Dentries in
971 * lowerstack are stale. We cannot drop them here because
972 * access to them is lockless. This could be only pure upper
973 * or opaque directory - numlower is zero. Or upper non-dir
974 * entry - its pureness is tracked by flag opaque.
975 */
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200976 if (old_opaque != new_opaque) {
977 ovl_dentry_set_opaque(old, new_opaque);
978 if (!overwrite)
979 ovl_dentry_set_opaque(new, old_opaque);
980 }
981
982 if (cleanup_whiteout)
983 ovl_cleanup(old_upperdir->d_inode, newdentry);
984
985 ovl_dentry_version_inc(old->d_parent);
986 ovl_dentry_version_inc(new->d_parent);
987
988out_dput:
989 dput(newdentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100990out_dput_old:
991 dput(olddentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200992out_unlock:
993 unlock_rename(new_upperdir, old_upperdir);
994out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400995 revert_creds(old_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200996out_drop_write:
997 ovl_drop_write(old);
998out:
999 dput(opaquedir);
1000 return err;
1001}
1002
1003const struct inode_operations ovl_dir_inode_operations = {
1004 .lookup = ovl_lookup,
1005 .mkdir = ovl_mkdir,
1006 .symlink = ovl_symlink,
1007 .unlink = ovl_unlink,
1008 .rmdir = ovl_rmdir,
1009 .rename2 = ovl_rename2,
1010 .link = ovl_link,
1011 .setattr = ovl_setattr,
1012 .create = ovl_create,
1013 .mknod = ovl_mknod,
1014 .permission = ovl_permission,
1015 .getattr = ovl_dir_getattr,
Miklos Szeredid837a492016-07-29 12:05:24 +02001016 .setxattr = generic_setxattr,
Andreas Gruenbacher0eb45fc2016-08-22 17:52:55 +02001017 .getxattr = generic_getxattr,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001018 .listxattr = ovl_listxattr,
Andreas Gruenbacher0e585cc2016-08-22 17:22:11 +02001019 .removexattr = generic_removexattr,
Vivek Goyal39a25b22016-07-01 16:34:26 -04001020 .get_acl = ovl_get_acl,
Miklos Szeredid719e8f2016-07-29 12:05:23 +02001021 .update_time = ovl_update_time,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001022};