blob: 306b6c16184081f26579b25f830b1b6f5eb0c094 [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);
183}
184
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200185static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
186 struct kstat *stat, const char *link,
187 struct dentry *hardlink)
188{
189 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
190 struct inode *udir = upperdir->d_inode;
191 struct dentry *newdentry;
192 int err;
193
Miklos Szeredi38b25692016-09-01 11:11:59 +0200194 if (!hardlink && !IS_POSIXACL(udir))
195 stat->mode &= ~current_umask();
196
Al Viro59551022016-01-22 15:40:57 -0500197 inode_lock_nested(udir, I_MUTEX_PARENT);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200198 newdentry = lookup_one_len(dentry->d_name.name, upperdir,
199 dentry->d_name.len);
200 err = PTR_ERR(newdentry);
201 if (IS_ERR(newdentry))
202 goto out_unlock;
203 err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
204 if (err)
205 goto out_dput;
206
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200207 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200208 newdentry = NULL;
209out_dput:
210 dput(newdentry);
211out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500212 inode_unlock(udir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200213 return err;
214}
215
216static int ovl_lock_rename_workdir(struct dentry *workdir,
217 struct dentry *upperdir)
218{
219 /* Workdir should not be the same as upperdir */
220 if (workdir == upperdir)
221 goto err;
222
223 /* Workdir should not be subdir of upperdir and vice versa */
224 if (lock_rename(workdir, upperdir) != NULL)
225 goto err_unlock;
226
227 return 0;
228
229err_unlock:
230 unlock_rename(workdir, upperdir);
231err:
232 pr_err("overlayfs: failed to lock workdir+upperdir\n");
233 return -EIO;
234}
235
236static struct dentry *ovl_clear_empty(struct dentry *dentry,
237 struct list_head *list)
238{
239 struct dentry *workdir = ovl_workdir(dentry);
240 struct inode *wdir = workdir->d_inode;
241 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
242 struct inode *udir = upperdir->d_inode;
243 struct path upperpath;
244 struct dentry *upper;
245 struct dentry *opaquedir;
246 struct kstat stat;
247 int err;
248
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200249 if (WARN_ON(!workdir))
250 return ERR_PTR(-EROFS);
251
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200252 err = ovl_lock_rename_workdir(workdir, upperdir);
253 if (err)
254 goto out;
255
256 ovl_path_upper(dentry, &upperpath);
257 err = vfs_getattr(&upperpath, &stat);
258 if (err)
259 goto out_unlock;
260
261 err = -ESTALE;
262 if (!S_ISDIR(stat.mode))
263 goto out_unlock;
264 upper = upperpath.dentry;
265 if (upper->d_parent->d_inode != udir)
266 goto out_unlock;
267
268 opaquedir = ovl_lookup_temp(workdir, dentry);
269 err = PTR_ERR(opaquedir);
270 if (IS_ERR(opaquedir))
271 goto out_unlock;
272
273 err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
274 if (err)
275 goto out_dput;
276
277 err = ovl_copy_xattr(upper, opaquedir);
278 if (err)
279 goto out_cleanup;
280
281 err = ovl_set_opaque(opaquedir);
282 if (err)
283 goto out_cleanup;
284
Al Viro59551022016-01-22 15:40:57 -0500285 inode_lock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200286 err = ovl_set_attr(opaquedir, &stat);
Al Viro59551022016-01-22 15:40:57 -0500287 inode_unlock(opaquedir->d_inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200288 if (err)
289 goto out_cleanup;
290
291 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
292 if (err)
293 goto out_cleanup;
294
295 ovl_cleanup_whiteouts(upper, list);
296 ovl_cleanup(wdir, upper);
297 unlock_rename(workdir, upperdir);
298
299 /* dentry's upper doesn't match now, get rid of it */
300 d_drop(dentry);
301
302 return opaquedir;
303
304out_cleanup:
305 ovl_cleanup(wdir, opaquedir);
306out_dput:
307 dput(opaquedir);
308out_unlock:
309 unlock_rename(workdir, upperdir);
310out:
311 return ERR_PTR(err);
312}
313
Miklos Szeredia105d682014-11-20 16:39:59 +0100314static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200315{
316 int err;
317 struct dentry *ret = NULL;
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200318 enum ovl_path_type type = ovl_path_type(dentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200319 LIST_HEAD(list);
320
321 err = ovl_check_empty_dir(dentry, &list);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200322 if (err) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200323 ret = ERR_PTR(err);
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200324 goto out_free;
Miklos Szeredia105d682014-11-20 16:39:59 +0100325 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200326
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200327 /*
328 * When removing an empty opaque directory, then it makes no sense to
329 * replace it with an exact replica of itself.
330 *
331 * If no upperdentry then skip clearing whiteouts.
332 *
333 * Can race with copy-up, since we don't hold the upperdir mutex.
334 * Doesn't matter, since copy-up can't create a non-empty directory
335 * from an empty one.
336 */
337 if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
338 ret = ovl_clear_empty(dentry, &list);
339
340out_free:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200341 ovl_cache_free(&list);
342
343 return ret;
344}
345
Miklos Szeredi38b25692016-09-01 11:11:59 +0200346static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
347 const struct posix_acl *acl)
348{
349 void *buffer;
350 size_t size;
351 int err;
352
353 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
354 return 0;
355
356 size = posix_acl_to_xattr(NULL, acl, NULL, 0);
357 buffer = kmalloc(size, GFP_KERNEL);
358 if (!buffer)
359 return -ENOMEM;
360
361 size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
362 err = size;
363 if (err < 0)
364 goto out_free;
365
366 err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
367out_free:
368 kfree(buffer);
369 return err;
370}
371
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200372static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
373 struct kstat *stat, const char *link,
374 struct dentry *hardlink)
375{
376 struct dentry *workdir = ovl_workdir(dentry);
377 struct inode *wdir = workdir->d_inode;
378 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
379 struct inode *udir = upperdir->d_inode;
380 struct dentry *upper;
381 struct dentry *newdentry;
382 int err;
Miklos Szeredi38b25692016-09-01 11:11:59 +0200383 struct posix_acl *acl, *default_acl;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200384
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200385 if (WARN_ON(!workdir))
386 return -EROFS;
387
Miklos Szeredi38b25692016-09-01 11:11:59 +0200388 if (!hardlink) {
389 err = posix_acl_create(dentry->d_parent->d_inode,
390 &stat->mode, &default_acl, &acl);
391 if (err)
392 return err;
393 }
394
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200395 err = ovl_lock_rename_workdir(workdir, upperdir);
396 if (err)
397 goto out;
398
399 newdentry = ovl_lookup_temp(workdir, dentry);
400 err = PTR_ERR(newdentry);
401 if (IS_ERR(newdentry))
402 goto out_unlock;
403
404 upper = lookup_one_len(dentry->d_name.name, upperdir,
405 dentry->d_name.len);
406 err = PTR_ERR(upper);
407 if (IS_ERR(upper))
408 goto out_dput;
409
410 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
411 if (err)
412 goto out_dput2;
413
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200414 /*
415 * mode could have been mutilated due to umask (e.g. sgid directory)
416 */
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200417 if (!hardlink &&
418 !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200419 struct iattr attr = {
420 .ia_valid = ATTR_MODE,
421 .ia_mode = stat->mode,
422 };
423 inode_lock(newdentry->d_inode);
424 err = notify_change(newdentry, &attr, NULL);
425 inode_unlock(newdentry->d_inode);
426 if (err)
427 goto out_cleanup;
428 }
Miklos Szeredi38b25692016-09-01 11:11:59 +0200429 if (!hardlink) {
430 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
431 acl);
432 if (err)
433 goto out_cleanup;
434
435 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
436 default_acl);
437 if (err)
438 goto out_cleanup;
439 }
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200440
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200441 if (!hardlink && S_ISDIR(stat->mode)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200442 err = ovl_set_opaque(newdentry);
443 if (err)
444 goto out_cleanup;
445
446 err = ovl_do_rename(wdir, newdentry, udir, upper,
447 RENAME_EXCHANGE);
448 if (err)
449 goto out_cleanup;
450
451 ovl_cleanup(wdir, upper);
452 } else {
453 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
454 if (err)
455 goto out_cleanup;
456 }
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200457 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200458 newdentry = NULL;
459out_dput2:
460 dput(upper);
461out_dput:
462 dput(newdentry);
463out_unlock:
464 unlock_rename(workdir, upperdir);
465out:
Miklos Szeredi38b25692016-09-01 11:11:59 +0200466 if (!hardlink) {
467 posix_acl_release(acl);
468 posix_acl_release(default_acl);
469 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200470 return err;
471
472out_cleanup:
473 ovl_cleanup(wdir, newdentry);
474 goto out_dput2;
475}
476
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200477static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
478 struct kstat *stat, const char *link,
479 struct dentry *hardlink)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200480{
481 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400482 const struct cred *old_cred;
483 struct cred *override_cred;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200484
485 err = ovl_copy_up(dentry->d_parent);
486 if (err)
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200487 return err;
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200488
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400489 old_cred = ovl_override_creds(dentry->d_sb);
490 err = -ENOMEM;
491 override_cred = prepare_creds();
492 if (override_cred) {
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200493 override_cred->fsuid = inode->i_uid;
494 override_cred->fsgid = inode->i_gid;
Vivek Goyal26026252016-07-13 10:44:52 -0400495 if (!hardlink) {
496 err = security_dentry_create_files_as(dentry,
497 stat->mode, &dentry->d_name, old_cred,
498 override_cred);
499 if (err) {
500 put_cred(override_cred);
501 goto out_revert_creds;
502 }
503 }
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400504 put_cred(override_creds(override_cred));
505 put_cred(override_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200506
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400507 if (!ovl_dentry_is_opaque(dentry))
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200508 err = ovl_create_upper(dentry, inode, stat, link,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400509 hardlink);
510 else
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200511 err = ovl_create_over_whiteout(dentry, inode, stat,
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400512 link, hardlink);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200513 }
Vivek Goyal26026252016-07-13 10:44:52 -0400514out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400515 revert_creds(old_cred);
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200516 if (!err) {
517 struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
518
519 WARN_ON(inode->i_mode != realinode->i_mode);
520 WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
521 WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
Miklos Szeredibb0d2b82016-07-29 12:05:23 +0200522 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200523 return err;
524}
525
526static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
527 const char *link)
528{
529 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200530 struct inode *inode;
531 struct kstat stat = {
532 .rdev = rdev,
533 };
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200534
535 err = ovl_want_write(dentry);
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200536 if (err)
537 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200538
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200539 err = -ENOMEM;
540 inode = ovl_new_inode(dentry->d_sb, mode);
541 if (!inode)
542 goto out_drop_write;
543
544 inode_init_owner(inode, dentry->d_parent->d_inode, mode);
545 stat.mode = inode->i_mode;
546
547 err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
548 if (err)
549 iput(inode);
550
551out_drop_write:
552 ovl_drop_write(dentry);
553out:
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200554 return err;
555}
556
557static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
558 bool excl)
559{
560 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
561}
562
563static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
564{
565 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
566}
567
568static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
569 dev_t rdev)
570{
571 /* Don't allow creation of "whiteout" on overlay */
572 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
573 return -EPERM;
574
575 return ovl_create_object(dentry, mode, rdev, NULL);
576}
577
578static int ovl_symlink(struct inode *dir, struct dentry *dentry,
579 const char *link)
580{
581 return ovl_create_object(dentry, S_IFLNK, 0, link);
582}
583
584static int ovl_link(struct dentry *old, struct inode *newdir,
585 struct dentry *new)
586{
587 int err;
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200588 struct inode *inode;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200589
590 err = ovl_want_write(old);
591 if (err)
592 goto out;
593
594 err = ovl_copy_up(old);
595 if (err)
596 goto out_drop_write;
597
Miklos Szeredi51f7e522016-07-29 12:05:24 +0200598 inode = d_inode(old);
599 ihold(inode);
600
601 err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
602 if (err)
603 iput(inode);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200604
605out_drop_write:
606 ovl_drop_write(old);
607out:
608 return err;
609}
610
Miklos Szeredia105d682014-11-20 16:39:59 +0100611static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200612{
613 struct dentry *workdir = ovl_workdir(dentry);
614 struct inode *wdir = workdir->d_inode;
615 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
616 struct inode *udir = upperdir->d_inode;
617 struct dentry *whiteout;
618 struct dentry *upper;
619 struct dentry *opaquedir = NULL;
620 int err;
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700621 int flags = 0;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200622
Miklos Szeredicc6f67b2015-05-19 14:30:12 +0200623 if (WARN_ON(!workdir))
624 return -EROFS;
625
Miklos Szeredid377c5e2015-05-14 10:04:44 +0200626 if (is_dir) {
Miklos Szeredi30c17eb2016-07-29 12:05:25 +0200627 opaquedir = ovl_check_empty_and_clear(dentry);
628 err = PTR_ERR(opaquedir);
629 if (IS_ERR(opaquedir))
630 goto out;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200631 }
632
633 err = ovl_lock_rename_workdir(workdir, upperdir);
634 if (err)
635 goto out_dput;
636
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700637 upper = lookup_one_len(dentry->d_name.name, upperdir,
638 dentry->d_name.len);
639 err = PTR_ERR(upper);
640 if (IS_ERR(upper))
641 goto out_unlock;
642
643 err = -ESTALE;
644 if ((opaquedir && upper != opaquedir) ||
645 (!opaquedir && ovl_dentry_upper(dentry) &&
646 upper != ovl_dentry_upper(dentry))) {
647 goto out_dput_upper;
648 }
649
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200650 whiteout = ovl_whiteout(workdir, dentry);
651 err = PTR_ERR(whiteout);
652 if (IS_ERR(whiteout))
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700653 goto out_dput_upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200654
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700655 if (d_is_dir(upper))
656 flags = RENAME_EXCHANGE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200657
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700658 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
659 if (err)
660 goto kill_whiteout;
661 if (flags)
662 ovl_cleanup(wdir, upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200663
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200664 ovl_dentry_version_inc(dentry->d_parent);
665out_d_drop:
666 d_drop(dentry);
667 dput(whiteout);
Maxim Patlasovcfc9fde2016-07-21 18:24:26 -0700668out_dput_upper:
669 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200670out_unlock:
671 unlock_rename(workdir, upperdir);
672out_dput:
673 dput(opaquedir);
674out:
675 return err;
676
677kill_whiteout:
678 ovl_cleanup(wdir, whiteout);
679 goto out_d_drop;
680}
681
682static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
683{
684 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
685 struct inode *dir = upperdir->d_inode;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100686 struct dentry *upper;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200687 int err;
688
Al Viro59551022016-01-22 15:40:57 -0500689 inode_lock_nested(dir, I_MUTEX_PARENT);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100690 upper = lookup_one_len(dentry->d_name.name, upperdir,
691 dentry->d_name.len);
692 err = PTR_ERR(upper);
693 if (IS_ERR(upper))
694 goto out_unlock;
695
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200696 err = -ESTALE;
Miklos Szeredi11f37102016-03-21 17:31:44 +0100697 if (upper == ovl_dentry_upper(dentry)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200698 if (is_dir)
699 err = vfs_rmdir(dir, upper);
700 else
701 err = vfs_unlink(dir, upper, NULL);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200702 ovl_dentry_version_inc(dentry->d_parent);
703 }
Miklos Szeredi11f37102016-03-21 17:31:44 +0100704 dput(upper);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200705
706 /*
707 * Keeping this dentry hashed would mean having to release
708 * upperpath/lowerpath, which could only be done if we are the
709 * sole user of this dentry. Too tricky... Just unhash for
710 * now.
711 */
Rui Wangce9113b2016-01-08 23:09:59 +0800712 if (!err)
713 d_drop(dentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100714out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500715 inode_unlock(dir);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200716
717 return err;
718}
719
720static inline int ovl_check_sticky(struct dentry *dentry)
721{
722 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
723 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
724
725 if (check_sticky(dir, inode))
726 return -EPERM;
727
728 return 0;
729}
730
731static int ovl_do_remove(struct dentry *dentry, bool is_dir)
732{
733 enum ovl_path_type type;
734 int err;
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400735 const struct cred *old_cred;
736
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200737
738 err = ovl_check_sticky(dentry);
739 if (err)
740 goto out;
741
742 err = ovl_want_write(dentry);
743 if (err)
744 goto out;
745
746 err = ovl_copy_up(dentry->d_parent);
747 if (err)
748 goto out_drop_write;
749
750 type = ovl_path_type(dentry);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400751
752 old_cred = ovl_override_creds(dentry->d_sb);
753 if (OVL_TYPE_PURE_UPPER(type))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200754 err = ovl_remove_upper(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400755 else
Miklos Szeredia105d682014-11-20 16:39:59 +0100756 err = ovl_remove_and_whiteout(dentry, is_dir);
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400757 revert_creds(old_cred);
Miklos Szeredidbc816d2016-07-29 12:05:24 +0200758 if (!err) {
759 if (is_dir)
760 clear_nlink(dentry->d_inode);
761 else
762 drop_nlink(dentry->d_inode);
763 }
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200764out_drop_write:
765 ovl_drop_write(dentry);
766out:
767 return err;
768}
769
770static int ovl_unlink(struct inode *dir, struct dentry *dentry)
771{
772 return ovl_do_remove(dentry, false);
773}
774
775static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
776{
777 return ovl_do_remove(dentry, true);
778}
779
780static int ovl_rename2(struct inode *olddir, struct dentry *old,
781 struct inode *newdir, struct dentry *new,
782 unsigned int flags)
783{
784 int err;
785 enum ovl_path_type old_type;
786 enum ovl_path_type new_type;
787 struct dentry *old_upperdir;
788 struct dentry *new_upperdir;
789 struct dentry *olddentry;
790 struct dentry *newdentry;
791 struct dentry *trap;
792 bool old_opaque;
793 bool new_opaque;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200794 bool cleanup_whiteout = false;
795 bool overwrite = !(flags & RENAME_EXCHANGE);
David Howellse36cb0b2015-01-29 12:02:35 +0000796 bool is_dir = d_is_dir(old);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200797 bool new_is_dir = false;
798 struct dentry *opaquedir = NULL;
799 const struct cred *old_cred = NULL;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200800
801 err = -EINVAL;
802 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
803 goto out;
804
805 flags &= ~RENAME_NOREPLACE;
806
807 err = ovl_check_sticky(old);
808 if (err)
809 goto out;
810
811 /* Don't copy up directory trees */
812 old_type = ovl_path_type(old);
813 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100814 if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200815 goto out;
816
817 if (new->d_inode) {
818 err = ovl_check_sticky(new);
819 if (err)
820 goto out;
821
David Howellse36cb0b2015-01-29 12:02:35 +0000822 if (d_is_dir(new))
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200823 new_is_dir = true;
824
825 new_type = ovl_path_type(new);
826 err = -EXDEV;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100827 if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200828 goto out;
829
830 err = 0;
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100831 if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200832 if (ovl_dentry_lower(old)->d_inode ==
833 ovl_dentry_lower(new)->d_inode)
834 goto out;
835 }
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100836 if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200837 if (ovl_dentry_upper(old)->d_inode ==
838 ovl_dentry_upper(new)->d_inode)
839 goto out;
840 }
841 } else {
842 if (ovl_dentry_is_opaque(new))
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100843 new_type = __OVL_PATH_UPPER;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200844 else
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100845 new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200846 }
847
848 err = ovl_want_write(old);
849 if (err)
850 goto out;
851
852 err = ovl_copy_up(old);
853 if (err)
854 goto out_drop_write;
855
856 err = ovl_copy_up(new->d_parent);
857 if (err)
858 goto out_drop_write;
859 if (!overwrite) {
860 err = ovl_copy_up(new);
861 if (err)
862 goto out_drop_write;
863 }
864
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100865 old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
866 new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200867
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400868 old_cred = ovl_override_creds(old->d_sb);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200869
Miklos Szeredi1afaba12014-12-13 00:59:42 +0100870 if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
Miklos Szeredia105d682014-11-20 16:39:59 +0100871 opaquedir = ovl_check_empty_and_clear(new);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200872 err = PTR_ERR(opaquedir);
873 if (IS_ERR(opaquedir)) {
874 opaquedir = NULL;
875 goto out_revert_creds;
876 }
877 }
878
879 if (overwrite) {
880 if (old_opaque) {
881 if (new->d_inode || !new_opaque) {
882 /* Whiteout source */
883 flags |= RENAME_WHITEOUT;
884 } else {
885 /* Switch whiteouts */
886 flags |= RENAME_EXCHANGE;
887 }
888 } else if (is_dir && !new->d_inode && new_opaque) {
889 flags |= RENAME_EXCHANGE;
890 cleanup_whiteout = true;
891 }
892 }
893
894 old_upperdir = ovl_dentry_upper(old->d_parent);
895 new_upperdir = ovl_dentry_upper(new->d_parent);
896
897 trap = lock_rename(new_upperdir, old_upperdir);
898
Miklos Szeredi11f37102016-03-21 17:31:44 +0100899
900 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
901 old->d_name.len);
902 err = PTR_ERR(olddentry);
903 if (IS_ERR(olddentry))
904 goto out_unlock;
905
906 err = -ESTALE;
907 if (olddentry != ovl_dentry_upper(old))
908 goto out_dput_old;
909
910 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
911 new->d_name.len);
912 err = PTR_ERR(newdentry);
913 if (IS_ERR(newdentry))
914 goto out_dput_old;
915
916 err = -ESTALE;
917 if (ovl_dentry_upper(new)) {
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200918 if (opaquedir) {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100919 if (newdentry != opaquedir)
920 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200921 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100922 if (newdentry != ovl_dentry_upper(new))
923 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200924 }
925 } else {
Miklos Szeredi11f37102016-03-21 17:31:44 +0100926 if (!d_is_negative(newdentry) &&
927 (!new_opaque || !ovl_is_whiteout(newdentry)))
928 goto out_dput;
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200929 }
930
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200931 if (olddentry == trap)
932 goto out_dput;
933 if (newdentry == trap)
934 goto out_dput;
935
936 if (is_dir && !old_opaque && new_opaque) {
937 err = ovl_set_opaque(olddentry);
938 if (err)
939 goto out_dput;
940 }
941 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
942 err = ovl_set_opaque(newdentry);
943 if (err)
944 goto out_dput;
945 }
946
947 if (old_opaque || new_opaque) {
948 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
949 new_upperdir->d_inode, newdentry,
950 flags);
951 } else {
952 /* No debug for the plain case */
953 BUG_ON(flags & ~RENAME_EXCHANGE);
954 err = vfs_rename(old_upperdir->d_inode, olddentry,
955 new_upperdir->d_inode, newdentry,
956 NULL, flags);
957 }
958
959 if (err) {
960 if (is_dir && !old_opaque && new_opaque)
961 ovl_remove_opaque(olddentry);
962 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
963 ovl_remove_opaque(newdentry);
964 goto out_dput;
965 }
966
967 if (is_dir && old_opaque && !new_opaque)
968 ovl_remove_opaque(olddentry);
969 if (!overwrite && new_is_dir && !old_opaque && new_opaque)
970 ovl_remove_opaque(newdentry);
971
Konstantin Khlebnikov45d11732016-01-31 16:17:53 +0300972 /*
973 * Old dentry now lives in different location. Dentries in
974 * lowerstack are stale. We cannot drop them here because
975 * access to them is lockless. This could be only pure upper
976 * or opaque directory - numlower is zero. Or upper non-dir
977 * entry - its pureness is tracked by flag opaque.
978 */
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200979 if (old_opaque != new_opaque) {
980 ovl_dentry_set_opaque(old, new_opaque);
981 if (!overwrite)
982 ovl_dentry_set_opaque(new, old_opaque);
983 }
984
985 if (cleanup_whiteout)
986 ovl_cleanup(old_upperdir->d_inode, newdentry);
987
988 ovl_dentry_version_inc(old->d_parent);
989 ovl_dentry_version_inc(new->d_parent);
990
991out_dput:
992 dput(newdentry);
Miklos Szeredi11f37102016-03-21 17:31:44 +0100993out_dput_old:
994 dput(olddentry);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200995out_unlock:
996 unlock_rename(new_upperdir, old_upperdir);
997out_revert_creds:
Vivek Goyal1175b6b2016-07-01 16:34:28 -0400998 revert_creds(old_cred);
Miklos Szeredie9be9d52014-10-24 00:14:38 +0200999out_drop_write:
1000 ovl_drop_write(old);
1001out:
1002 dput(opaquedir);
1003 return err;
1004}
1005
1006const struct inode_operations ovl_dir_inode_operations = {
1007 .lookup = ovl_lookup,
1008 .mkdir = ovl_mkdir,
1009 .symlink = ovl_symlink,
1010 .unlink = ovl_unlink,
1011 .rmdir = ovl_rmdir,
Miklos Szeredi2773bf02016-09-27 11:03:58 +02001012 .rename = ovl_rename2,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001013 .link = ovl_link,
1014 .setattr = ovl_setattr,
1015 .create = ovl_create,
1016 .mknod = ovl_mknod,
1017 .permission = ovl_permission,
1018 .getattr = ovl_dir_getattr,
Miklos Szeredie9be9d52014-10-24 00:14:38 +02001019 .listxattr = ovl_listxattr,
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};