blob: 8546384a5fdfd36577fddac11164223a410d9f05 [file] [log] [blame]
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>
Richard Weinberger6a45b362016-09-16 11:45:24 +020017#include <linux/atomic.h>
Miklos Szeredie9be9d52014-10-24 00:14:38 +020018#include "overlayfs.h"
19
20void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
21{
22 int err;
23
24 dget(wdentry);
David Howellse36cb0b2015-01-29 12:02:35 +000025 if (d_is_dir(wdentry))
Miklos Szeredie9be9d52014-10-24 00:14:38 +020026 err = ovl_do_rmdir(wdir, wdentry);
27 else
28 err = ovl_do_unlink(wdir, wdentry);
29 dput(wdentry);
30
31 if (err) {
32 pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
33 wdentry, err);
34 }
35}
36
37struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
38{
39 struct dentry *temp;
40 char name[20];
Richard Weinberger6a45b362016-09-16 11:45:24 +020041 static atomic_t temp_id = ATOMIC_INIT(0);
Miklos Szeredie9be9d52014-10-24 00:14:38 +020042
Richard Weinberger6a45b362016-09-16 11:45:24 +020043 /* counter is allowed to wrap, since temp dentries are ephemeral */
44 snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
Miklos Szeredie9be9d52014-10-24 00:14:38 +020045
46 temp = lookup_one_len(name, workdir, strlen(name));
47 if (!IS_ERR(temp) && temp->d_inode) {
48 pr_err("overlayfs: workdir/%s already exists\n", name);
49 dput(temp);
50 temp = ERR_PTR(-EIO);
51 }
52
53 return temp;
54}
55
56/* caller holds i_mutex on workdir */
57static struct dentry *ovl_whiteout(struct dentry *workdir,
58 struct dentry *dentry)
59{
60 int err;
61 struct dentry *whiteout;
62 struct inode *wdir = workdir->d_inode;
63
64 whiteout = ovl_lookup_temp(workdir, dentry);
65 if (IS_ERR(whiteout))
66 return whiteout;
67
68 err = ovl_do_whiteout(wdir, whiteout);
69 if (err) {
70 dput(whiteout);
71 whiteout = ERR_PTR(err);
72 }
73
74 return whiteout;
75}
76
77int ovl_create_real(struct inode *dir, struct dentry *newdentry,
78 struct kstat *stat, const char *link,
79 struct dentry *hardlink, bool debug)
80{
81 int err;
82
83 if (newdentry->d_inode)
84 return -ESTALE;
85
86 if (hardlink) {
87 err = ovl_do_link(hardlink, dir, newdentry, debug);
88 } else {
89 switch (stat->mode & S_IFMT) {
90 case S_IFREG:
91 err = ovl_do_create(dir, newdentry, stat->mode, debug);
92 break;
93
94 case S_IFDIR:
95 err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
96 break;
97
98 case S_IFCHR:
99 case S_IFBLK:
100 case S_IFIFO:
101 case S_IFSOCK:
102 err = ovl_do_mknod(dir, newdentry,
103 stat->mode, stat->rdev, debug);
104 break;
105
106 case S_IFLNK:
107 err = ovl_do_symlink(dir, newdentry, link, debug);
108 break;
109
110 default:
111 err = -EPERM;
112 }
113 }
114 if (!err && WARN_ON(!newdentry->d_inode)) {
115 /*
116 * Not quite sure if non-instantiated dentry is legal or not.
117 * VFS doesn't seem to care so check and warn here.
118 */
119 err = -ENOENT;
120 }
121 return err;
122}
123
124static int ovl_set_opaque(struct dentry *upperdentry)
125{
hujianyangcead89b2014-11-24 18:25:21 +0800126 return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200127}
128
129static void ovl_remove_opaque(struct dentry *upperdentry)
130{
131 int err;
132
hujianyangcead89b2014-11-24 18:25:21 +0800133 err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200134 if (err) {
135 pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
136 upperdentry->d_name.name, err);
137 }
138}
139
140static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
141 struct kstat *stat)
142{
143 int err;
144 enum ovl_path_type type;
145 struct path realpath;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400146 const struct cred *old_cred;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200147
148 type = ovl_path_real(dentry, &realpath);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400149 old_cred = ovl_override_creds(dentry->d_sb);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200150 err = vfs_getattr(&realpath, stat);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400151 revert_creds(old_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200152 if (err)
153 return err;
154
155 stat->dev = dentry->d_sb->s_dev;
156 stat->ino = dentry->d_inode->i_ino;
157
158 /*
159 * It's probably not worth it to count subdirs to get the
160 * correct link count. nlink=1 seems to pacify 'find' and
161 * other utilities.
162 */
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100163 if (OVL_TYPE_MERGE(type))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200164 stat->nlink = 1;
165
166 return 0;
167}
168
Vivek Goyal72e48482016-06-16 10:09:14 -0400169/* Common operations required to be done after creation of file on upper */
170static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200171 struct dentry *newdentry, bool hardlink)
Vivek Goyal72e48482016-06-16 10:09:14 -0400172{
173 ovl_dentry_version_inc(dentry->d_parent);
174 ovl_dentry_update(dentry, newdentry);
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200175 if (!hardlink) {
176 ovl_inode_update(inode, d_inode(newdentry));
177 ovl_copyattr(newdentry->d_inode, inode);
178 } else {
179 WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
180 inc_nlink(inode);
181 }
Vivek Goyal72e48482016-06-16 10:09:14 -0400182 d_instantiate(dentry, inode);
Amir Goldstein6371afa2017-04-24 19:54:13 +0300183 /* Force lookup of new upper hardlink to find its lower */
184 if (hardlink)
185 d_drop(dentry);
Vivek Goyal72e48482016-06-16 10:09:14 -0400186}
187
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200188static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
189 struct kstat *stat, const char *link,
190 struct dentry *hardlink)
191{
192 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
193 struct inode *udir = upperdir->d_inode;
194 struct dentry *newdentry;
195 int err;
196
Miklos Szeredi38b25692016-09-01 11:11:59 +0200197 if (!hardlink && !IS_POSIXACL(udir))
198 stat->mode &= ~current_umask();
199
Al Viro59551022016-01-22 15:40:57 -0500200 inode_lock_nested(udir, I_MUTEX_PARENT);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200201 newdentry = lookup_one_len(dentry->d_name.name, upperdir,
202 dentry->d_name.len);
203 err = PTR_ERR(newdentry);
204 if (IS_ERR(newdentry))
205 goto out_unlock;
206 err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
207 if (err)
208 goto out_dput;
209
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200210 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200211 newdentry = NULL;
212out_dput:
213 dput(newdentry);
214out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500215 inode_unlock(udir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200216 return err;
217}
218
219static int ovl_lock_rename_workdir(struct dentry *workdir,
220 struct dentry *upperdir)
221{
222 /* Workdir should not be the same as upperdir */
223 if (workdir == upperdir)
224 goto err;
225
226 /* Workdir should not be subdir of upperdir and vice versa */
227 if (lock_rename(workdir, upperdir) != NULL)
228 goto err_unlock;
229
230 return 0;
231
232err_unlock:
233 unlock_rename(workdir, upperdir);
234err:
235 pr_err("overlayfs: failed to lock workdir+upperdir\n");
236 return -EIO;
237}
238
239static struct dentry *ovl_clear_empty(struct dentry *dentry,
240 struct list_head *list)
241{
242 struct dentry *workdir = ovl_workdir(dentry);
243 struct inode *wdir = workdir->d_inode;
244 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
245 struct inode *udir = upperdir->d_inode;
246 struct path upperpath;
247 struct dentry *upper;
248 struct dentry *opaquedir;
249 struct kstat stat;
250 int err;
251
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200252 if (WARN_ON(!workdir))
253 return ERR_PTR(-EROFS);
254
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200255 err = ovl_lock_rename_workdir(workdir, upperdir);
256 if (err)
257 goto out;
258
259 ovl_path_upper(dentry, &upperpath);
260 err = vfs_getattr(&upperpath, &stat);
261 if (err)
262 goto out_unlock;
263
264 err = -ESTALE;
265 if (!S_ISDIR(stat.mode))
266 goto out_unlock;
267 upper = upperpath.dentry;
268 if (upper->d_parent->d_inode != udir)
269 goto out_unlock;
270
271 opaquedir = ovl_lookup_temp(workdir, dentry);
272 err = PTR_ERR(opaquedir);
273 if (IS_ERR(opaquedir))
274 goto out_unlock;
275
276 err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
277 if (err)
278 goto out_dput;
279
280 err = ovl_copy_xattr(upper, opaquedir);
281 if (err)
282 goto out_cleanup;
283
284 err = ovl_set_opaque(opaquedir);
285 if (err)
286 goto out_cleanup;
287
Al Viro59551022016-01-22 15:40:57 -0500288 inode_lock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200289 err = ovl_set_attr(opaquedir, &stat);
Al Viro59551022016-01-22 15:40:57 -0500290 inode_unlock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200291 if (err)
292 goto out_cleanup;
293
294 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
295 if (err)
296 goto out_cleanup;
297
298 ovl_cleanup_whiteouts(upper, list);
299 ovl_cleanup(wdir, upper);
300 unlock_rename(workdir, upperdir);
301
302 /* dentry's upper doesn't match now, get rid of it */
303 d_drop(dentry);
304
305 return opaquedir;
306
307out_cleanup:
308 ovl_cleanup(wdir, opaquedir);
309out_dput:
310 dput(opaquedir);
311out_unlock:
312 unlock_rename(workdir, upperdir);
313out:
314 return ERR_PTR(err);
315}
316
Miklos Szeredia105d682014-11-20 16:39:59 +0100317static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200318{
319 int err;
320 struct dentry *ret = NULL;
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200321 enum ovl_path_type type = ovl_path_type(dentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200322 LIST_HEAD(list);
323
324 err = ovl_check_empty_dir(dentry, &list);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200325 if (err) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200326 ret = ERR_PTR(err);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200327 goto out_free;
Miklos Szeredia105d682014-11-20 16:39:59 +0100328 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200329
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200330 /*
331 * When removing an empty opaque directory, then it makes no sense to
332 * replace it with an exact replica of itself.
333 *
334 * If no upperdentry then skip clearing whiteouts.
335 *
336 * Can race with copy-up, since we don't hold the upperdir mutex.
337 * Doesn't matter, since copy-up can't create a non-empty directory
338 * from an empty one.
339 */
340 if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
341 ret = ovl_clear_empty(dentry, &list);
342
343out_free:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200344 ovl_cache_free(&list);
345
346 return ret;
347}
348
Miklos Szeredi38b25692016-09-01 11:11:59 +0200349static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
350 const struct posix_acl *acl)
351{
352 void *buffer;
353 size_t size;
354 int err;
355
356 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
357 return 0;
358
359 size = posix_acl_to_xattr(NULL, acl, NULL, 0);
360 buffer = kmalloc(size, GFP_KERNEL);
361 if (!buffer)
362 return -ENOMEM;
363
364 size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
365 err = size;
366 if (err < 0)
367 goto out_free;
368
369 err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
370out_free:
371 kfree(buffer);
372 return err;
373}
374
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200375static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
376 struct kstat *stat, const char *link,
377 struct dentry *hardlink)
378{
379 struct dentry *workdir = ovl_workdir(dentry);
380 struct inode *wdir = workdir->d_inode;
381 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
382 struct inode *udir = upperdir->d_inode;
383 struct dentry *upper;
384 struct dentry *newdentry;
385 int err;
Miklos Szeredi38b25692016-09-01 11:11:59 +0200386 struct posix_acl *acl, *default_acl;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200387
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200388 if (WARN_ON(!workdir))
389 return -EROFS;
390
Miklos Szeredi38b25692016-09-01 11:11:59 +0200391 if (!hardlink) {
392 err = posix_acl_create(dentry->d_parent->d_inode,
393 &stat->mode, &default_acl, &acl);
394 if (err)
395 return err;
396 }
397
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200398 err = ovl_lock_rename_workdir(workdir, upperdir);
399 if (err)
400 goto out;
401
402 newdentry = ovl_lookup_temp(workdir, dentry);
403 err = PTR_ERR(newdentry);
404 if (IS_ERR(newdentry))
405 goto out_unlock;
406
407 upper = lookup_one_len(dentry->d_name.name, upperdir,
408 dentry->d_name.len);
409 err = PTR_ERR(upper);
410 if (IS_ERR(upper))
411 goto out_dput;
412
413 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
414 if (err)
415 goto out_dput2;
416
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200417 /*
418 * mode could have been mutilated due to umask (e.g. sgid directory)
419 */
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200420 if (!hardlink &&
421 !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200422 struct iattr attr = {
423 .ia_valid = ATTR_MODE,
424 .ia_mode = stat->mode,
425 };
426 inode_lock(newdentry->d_inode);
427 err = notify_change(newdentry, &attr, NULL);
428 inode_unlock(newdentry->d_inode);
429 if (err)
430 goto out_cleanup;
431 }
Miklos Szeredi38b25692016-09-01 11:11:59 +0200432 if (!hardlink) {
433 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
434 acl);
435 if (err)
436 goto out_cleanup;
437
438 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
439 default_acl);
440 if (err)
441 goto out_cleanup;
442 }
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200443
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200444 if (!hardlink && S_ISDIR(stat->mode)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200445 err = ovl_set_opaque(newdentry);
446 if (err)
447 goto out_cleanup;
448
449 err = ovl_do_rename(wdir, newdentry, udir, upper,
450 RENAME_EXCHANGE);
451 if (err)
452 goto out_cleanup;
453
454 ovl_cleanup(wdir, upper);
455 } else {
456 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
457 if (err)
458 goto out_cleanup;
459 }
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200460 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200461 newdentry = NULL;
462out_dput2:
463 dput(upper);
464out_dput:
465 dput(newdentry);
466out_unlock:
467 unlock_rename(workdir, upperdir);
468out:
Miklos Szeredi38b25692016-09-01 11:11:59 +0200469 if (!hardlink) {
470 posix_acl_release(acl);
471 posix_acl_release(default_acl);
472 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200473 return err;
474
475out_cleanup:
476 ovl_cleanup(wdir, newdentry);
477 goto out_dput2;
478}
479
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200480static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
481 struct kstat *stat, const char *link,
482 struct dentry *hardlink)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200483{
484 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400485 const struct cred *old_cred;
486 struct cred *override_cred;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200487
488 err = ovl_copy_up(dentry->d_parent);
489 if (err)
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200490 return err;
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200491
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400492 old_cred = ovl_override_creds(dentry->d_sb);
493 err = -ENOMEM;
494 override_cred = prepare_creds();
495 if (override_cred) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200496 override_cred->fsuid = inode->i_uid;
497 override_cred->fsgid = inode->i_gid;
Vivek Goyal26026252016-07-13 10:44:52 -0400498 if (!hardlink) {
499 err = security_dentry_create_files_as(dentry,
500 stat->mode, &dentry->d_name, old_cred,
501 override_cred);
502 if (err) {
503 put_cred(override_cred);
504 goto out_revert_creds;
505 }
506 }
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400507 put_cred(override_creds(override_cred));
508 put_cred(override_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200509
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400510 if (!ovl_dentry_is_opaque(dentry))
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200511 err = ovl_create_upper(dentry, inode, stat, link,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400512 hardlink);
513 else
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200514 err = ovl_create_over_whiteout(dentry, inode, stat,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400515 link, hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200516 }
Vivek Goyal26026252016-07-13 10:44:52 -0400517out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400518 revert_creds(old_cred);
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200519 if (!err) {
520 struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
521
522 WARN_ON(inode->i_mode != realinode->i_mode);
523 WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
524 WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200525 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200526 return err;
527}
528
529static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
530 const char *link)
531{
532 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200533 struct inode *inode;
534 struct kstat stat = {
535 .rdev = rdev,
536 };
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200537
538 err = ovl_want_write(dentry);
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200539 if (err)
540 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200541
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200542 err = -ENOMEM;
543 inode = ovl_new_inode(dentry->d_sb, mode);
544 if (!inode)
545 goto out_drop_write;
546
547 inode_init_owner(inode, dentry->d_parent->d_inode, mode);
548 stat.mode = inode->i_mode;
549
550 err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
551 if (err)
552 iput(inode);
553
554out_drop_write:
555 ovl_drop_write(dentry);
556out:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200557 return err;
558}
559
560static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
561 bool excl)
562{
563 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
564}
565
566static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
567{
568 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
569}
570
571static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
572 dev_t rdev)
573{
574 /* Don't allow creation of "whiteout" on overlay */
575 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
576 return -EPERM;
577
578 return ovl_create_object(dentry, mode, rdev, NULL);
579}
580
581static int ovl_symlink(struct inode *dir, struct dentry *dentry,
582 const char *link)
583{
584 return ovl_create_object(dentry, S_IFLNK, 0, link);
585}
586
587static int ovl_link(struct dentry *old, struct inode *newdir,
588 struct dentry *new)
589{
590 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200591 struct inode *inode;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200592
593 err = ovl_want_write(old);
594 if (err)
595 goto out;
596
597 err = ovl_copy_up(old);
598 if (err)
599 goto out_drop_write;
600
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200601 inode = d_inode(old);
602 ihold(inode);
603
604 err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
605 if (err)
606 iput(inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200607
608out_drop_write:
609 ovl_drop_write(old);
610out:
611 return err;
612}
613
Miklos Szeredia105d682014-11-20 16:39:59 +0100614static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200615{
616 struct dentry *workdir = ovl_workdir(dentry);
617 struct inode *wdir = workdir->d_inode;
618 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
619 struct inode *udir = upperdir->d_inode;
620 struct dentry *whiteout;
621 struct dentry *upper;
622 struct dentry *opaquedir = NULL;
623 int err;
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700624 int flags = 0;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200625
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200626 if (WARN_ON(!workdir))
627 return -EROFS;
628
Miklos Szeredid377c5e2015-05-14 10:04:44 +0200629 if (is_dir) {
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200630 opaquedir = ovl_check_empty_and_clear(dentry);
631 err = PTR_ERR(opaquedir);
632 if (IS_ERR(opaquedir))
633 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200634 }
635
636 err = ovl_lock_rename_workdir(workdir, upperdir);
637 if (err)
638 goto out_dput;
639
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700640 upper = lookup_one_len(dentry->d_name.name, upperdir,
641 dentry->d_name.len);
642 err = PTR_ERR(upper);
643 if (IS_ERR(upper))
644 goto out_unlock;
645
646 err = -ESTALE;
647 if ((opaquedir && upper != opaquedir) ||
648 (!opaquedir && ovl_dentry_upper(dentry) &&
649 upper != ovl_dentry_upper(dentry))) {
650 goto out_dput_upper;
651 }
652
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200653 whiteout = ovl_whiteout(workdir, dentry);
654 err = PTR_ERR(whiteout);
655 if (IS_ERR(whiteout))
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700656 goto out_dput_upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200657
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700658 if (d_is_dir(upper))
659 flags = RENAME_EXCHANGE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200660
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700661 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
662 if (err)
663 goto kill_whiteout;
664 if (flags)
665 ovl_cleanup(wdir, upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200666
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200667 ovl_dentry_version_inc(dentry->d_parent);
668out_d_drop:
669 d_drop(dentry);
670 dput(whiteout);
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700671out_dput_upper:
672 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200673out_unlock:
674 unlock_rename(workdir, upperdir);
675out_dput:
676 dput(opaquedir);
677out:
678 return err;
679
680kill_whiteout:
681 ovl_cleanup(wdir, whiteout);
682 goto out_d_drop;
683}
684
685static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
686{
687 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
688 struct inode *dir = upperdir->d_inode;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100689 struct dentry *upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200690 int err;
691
Al Viro59551022016-01-22 15:40:57 -0500692 inode_lock_nested(dir, I_MUTEX_PARENT);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100693 upper = lookup_one_len(dentry->d_name.name, upperdir,
694 dentry->d_name.len);
695 err = PTR_ERR(upper);
696 if (IS_ERR(upper))
697 goto out_unlock;
698
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200699 err = -ESTALE;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100700 if (upper == ovl_dentry_upper(dentry)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200701 if (is_dir)
702 err = vfs_rmdir(dir, upper);
703 else
704 err = vfs_unlink(dir, upper, NULL);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200705 ovl_dentry_version_inc(dentry->d_parent);
706 }
Miklos Szeredi11f37102016-03-21 17:31:44 +0100707 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200708
709 /*
710 * Keeping this dentry hashed would mean having to release
711 * upperpath/lowerpath, which could only be done if we are the
712 * sole user of this dentry. Too tricky... Just unhash for
713 * now.
714 */
Rui Wangce9113b2016-01-08 23:09:59 +0800715 if (!err)
716 d_drop(dentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100717out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500718 inode_unlock(dir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200719
720 return err;
721}
722
723static inline int ovl_check_sticky(struct dentry *dentry)
724{
725 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
726 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
727
728 if (check_sticky(dir, inode))
729 return -EPERM;
730
731 return 0;
732}
733
734static int ovl_do_remove(struct dentry *dentry, bool is_dir)
735{
736 enum ovl_path_type type;
737 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400738 const struct cred *old_cred;
739
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200740
741 err = ovl_check_sticky(dentry);
742 if (err)
743 goto out;
744
745 err = ovl_want_write(dentry);
746 if (err)
747 goto out;
748
749 err = ovl_copy_up(dentry->d_parent);
750 if (err)
751 goto out_drop_write;
752
753 type = ovl_path_type(dentry);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400754
755 old_cred = ovl_override_creds(dentry->d_sb);
756 if (OVL_TYPE_PURE_UPPER(type))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200757 err = ovl_remove_upper(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400758 else
Miklos Szeredia105d682014-11-20 16:39:59 +0100759 err = ovl_remove_and_whiteout(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400760 revert_creds(old_cred);
Miklos Szeredidbc816d2016-07-29 12:05:24 +0200761 if (!err) {
762 if (is_dir)
763 clear_nlink(dentry->d_inode);
764 else
765 drop_nlink(dentry->d_inode);
766 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200767out_drop_write:
768 ovl_drop_write(dentry);
769out:
770 return err;
771}
772
773static int ovl_unlink(struct inode *dir, struct dentry *dentry)
774{
775 return ovl_do_remove(dentry, false);
776}
777
778static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
779{
780 return ovl_do_remove(dentry, true);
781}
782
783static int ovl_rename2(struct inode *olddir, struct dentry *old,
784 struct inode *newdir, struct dentry *new,
785 unsigned int flags)
786{
787 int err;
788 enum ovl_path_type old_type;
789 enum ovl_path_type new_type;
790 struct dentry *old_upperdir;
791 struct dentry *new_upperdir;
792 struct dentry *olddentry;
793 struct dentry *newdentry;
794 struct dentry *trap;
795 bool old_opaque;
796 bool new_opaque;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200797 bool cleanup_whiteout = false;
798 bool overwrite = !(flags & RENAME_EXCHANGE);
David Howellse36cb0b2015-01-29 12:02:35 +0000799 bool is_dir = d_is_dir(old);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200800 bool new_is_dir = false;
801 struct dentry *opaquedir = NULL;
802 const struct cred *old_cred = NULL;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200803
804 err = -EINVAL;
805 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
806 goto out;
807
808 flags &= ~RENAME_NOREPLACE;
809
810 err = ovl_check_sticky(old);
811 if (err)
812 goto out;
813
814 /* Don't copy up directory trees */
815 old_type = ovl_path_type(old);
816 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100817 if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200818 goto out;
819
820 if (new->d_inode) {
821 err = ovl_check_sticky(new);
822 if (err)
823 goto out;
824
David Howellse36cb0b2015-01-29 12:02:35 +0000825 if (d_is_dir(new))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200826 new_is_dir = true;
827
828 new_type = ovl_path_type(new);
829 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100830 if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200831 goto out;
832
833 err = 0;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100834 if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200835 if (ovl_dentry_lower(old)->d_inode ==
836 ovl_dentry_lower(new)->d_inode)
837 goto out;
838 }
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100839 if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200840 if (ovl_dentry_upper(old)->d_inode ==
841 ovl_dentry_upper(new)->d_inode)
842 goto out;
843 }
844 } else {
845 if (ovl_dentry_is_opaque(new))
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100846 new_type = __OVL_PATH_UPPER;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200847 else
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100848 new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200849 }
850
851 err = ovl_want_write(old);
852 if (err)
853 goto out;
854
855 err = ovl_copy_up(old);
856 if (err)
857 goto out_drop_write;
858
859 err = ovl_copy_up(new->d_parent);
860 if (err)
861 goto out_drop_write;
862 if (!overwrite) {
863 err = ovl_copy_up(new);
864 if (err)
865 goto out_drop_write;
866 }
867
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100868 old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
869 new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200870
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400871 old_cred = ovl_override_creds(old->d_sb);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200872
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100873 if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
Miklos Szeredia105d682014-11-20 16:39:59 +0100874 opaquedir = ovl_check_empty_and_clear(new);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200875 err = PTR_ERR(opaquedir);
876 if (IS_ERR(opaquedir)) {
877 opaquedir = NULL;
878 goto out_revert_creds;
879 }
880 }
881
882 if (overwrite) {
883 if (old_opaque) {
884 if (new->d_inode || !new_opaque) {
885 /* Whiteout source */
886 flags |= RENAME_WHITEOUT;
887 } else {
888 /* Switch whiteouts */
889 flags |= RENAME_EXCHANGE;
890 }
891 } else if (is_dir && !new->d_inode && new_opaque) {
892 flags |= RENAME_EXCHANGE;
893 cleanup_whiteout = true;
894 }
895 }
896
897 old_upperdir = ovl_dentry_upper(old->d_parent);
898 new_upperdir = ovl_dentry_upper(new->d_parent);
899
900 trap = lock_rename(new_upperdir, old_upperdir);
901
Miklos Szeredi11f37102016-03-21 17:31:44 +0100902
903 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
904 old->d_name.len);
905 err = PTR_ERR(olddentry);
906 if (IS_ERR(olddentry))
907 goto out_unlock;
908
909 err = -ESTALE;
910 if (olddentry != ovl_dentry_upper(old))
911 goto out_dput_old;
912
913 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
914 new->d_name.len);
915 err = PTR_ERR(newdentry);
916 if (IS_ERR(newdentry))
917 goto out_dput_old;
918
919 err = -ESTALE;
920 if (ovl_dentry_upper(new)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200921 if (opaquedir) {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100922 if (newdentry != opaquedir)
923 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200924 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100925 if (newdentry != ovl_dentry_upper(new))
926 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200927 }
928 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100929 if (!d_is_negative(newdentry) &&
930 (!new_opaque || !ovl_is_whiteout(newdentry)))
931 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200932 }
933
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200934 if (olddentry == trap)
935 goto out_dput;
936 if (newdentry == trap)
937 goto out_dput;
938
939 if (is_dir && !old_opaque && new_opaque) {
940 err = ovl_set_opaque(olddentry);
941 if (err)
942 goto out_dput;
943 }
944 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
945 err = ovl_set_opaque(newdentry);
946 if (err)
947 goto out_dput;
948 }
949
950 if (old_opaque || new_opaque) {
951 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
952 new_upperdir->d_inode, newdentry,
953 flags);
954 } else {
955 /* No debug for the plain case */
956 BUG_ON(flags & ~RENAME_EXCHANGE);
957 err = vfs_rename(old_upperdir->d_inode, olddentry,
958 new_upperdir->d_inode, newdentry,
959 NULL, flags);
960 }
961
962 if (err) {
963 if (is_dir && !old_opaque && new_opaque)
964 ovl_remove_opaque(olddentry);
965 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
966 ovl_remove_opaque(newdentry);
967 goto out_dput;
968 }
969
970 if (is_dir && old_opaque && !new_opaque)
971 ovl_remove_opaque(olddentry);
972 if (!overwrite && new_is_dir && !old_opaque && new_opaque)
973 ovl_remove_opaque(newdentry);
974
Konstantin Khlebnikov45d11732016-01-31 16:17:53 +0300975 /*
976 * Old dentry now lives in different location. Dentries in
977 * lowerstack are stale. We cannot drop them here because
978 * access to them is lockless. This could be only pure upper
979 * or opaque directory - numlower is zero. Or upper non-dir
980 * entry - its pureness is tracked by flag opaque.
981 */
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200982 if (old_opaque != new_opaque) {
983 ovl_dentry_set_opaque(old, new_opaque);
984 if (!overwrite)
985 ovl_dentry_set_opaque(new, old_opaque);
986 }
987
988 if (cleanup_whiteout)
989 ovl_cleanup(old_upperdir->d_inode, newdentry);
990
991 ovl_dentry_version_inc(old->d_parent);
992 ovl_dentry_version_inc(new->d_parent);
993
994out_dput:
995 dput(newdentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100996out_dput_old:
997 dput(olddentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200998out_unlock:
999 unlock_rename(new_upperdir, old_upperdir);
1000out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -04001001 revert_creds(old_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001002out_drop_write:
1003 ovl_drop_write(old);
1004out:
1005 dput(opaquedir);
1006 return err;
1007}
1008
1009const struct inode_operations ovl_dir_inode_operations = {
1010 .lookup = ovl_lookup,
1011 .mkdir = ovl_mkdir,
1012 .symlink = ovl_symlink,
1013 .unlink = ovl_unlink,
1014 .rmdir = ovl_rmdir,
Miklos Szeredi2773bf02016-09-27 11:03:58 +02001015 .rename = ovl_rename2,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001016 .link = ovl_link,
1017 .setattr = ovl_setattr,
1018 .create = ovl_create,
1019 .mknod = ovl_mknod,
1020 .permission = ovl_permission,
1021 .getattr = ovl_dir_getattr,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001022 .listxattr = ovl_listxattr,
Vivek Goyal39a25b22016-07-01 16:34:26 -04001023 .get_acl = ovl_get_acl,
Miklos Szeredid719e8f2016-07-29 12:05:23 +02001024 .update_time = ovl_update_time,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001025};