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Miklos Szeredibbb1e542016-12-16 11:02:56 +01001/*
2 * Copyright (C) 2011 Novell Inc.
3 * Copyright (C) 2016 Red Hat, 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/mount.h>
12#include <linux/slab.h>
Ingo Molnar5b825c32017-02-02 17:54:15 +010013#include <linux/cred.h>
Miklos Szeredibbb1e542016-12-16 11:02:56 +010014#include <linux/xattr.h>
15#include "overlayfs.h"
16#include "ovl_entry.h"
17
18int ovl_want_write(struct dentry *dentry)
19{
20 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
21 return mnt_want_write(ofs->upper_mnt);
22}
23
24void ovl_drop_write(struct dentry *dentry)
25{
26 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
27 mnt_drop_write(ofs->upper_mnt);
28}
29
30struct dentry *ovl_workdir(struct dentry *dentry)
31{
32 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
33 return ofs->workdir;
34}
35
36const struct cred *ovl_override_creds(struct super_block *sb)
37{
38 struct ovl_fs *ofs = sb->s_fs_info;
39
40 return override_creds(ofs->creator_cred);
41}
42
Amir Goldstein7bcd74b2017-03-22 08:42:21 -040043struct super_block *ovl_same_sb(struct super_block *sb)
44{
45 struct ovl_fs *ofs = sb->s_fs_info;
46
47 return ofs->same_sb;
48}
49
Miklos Szeredibbb1e542016-12-16 11:02:56 +010050struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
51{
52 size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
53 struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
54
55 if (oe)
56 oe->numlower = numlower;
57
58 return oe;
59}
60
61bool ovl_dentry_remote(struct dentry *dentry)
62{
63 return dentry->d_flags &
64 (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
65 DCACHE_OP_REAL);
66}
67
68bool ovl_dentry_weird(struct dentry *dentry)
69{
70 return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
71 DCACHE_MANAGE_TRANSIT |
72 DCACHE_OP_HASH |
73 DCACHE_OP_COMPARE);
74}
75
76enum ovl_path_type ovl_path_type(struct dentry *dentry)
77{
78 struct ovl_entry *oe = dentry->d_fsdata;
79 enum ovl_path_type type = 0;
80
81 if (oe->__upperdentry) {
82 type = __OVL_PATH_UPPER;
83
84 /*
Amir Goldstein59548502017-04-23 23:12:34 +030085 * Non-dir dentry can hold lower dentry of its copy up origin.
Miklos Szeredibbb1e542016-12-16 11:02:56 +010086 */
Amir Goldstein59548502017-04-23 23:12:34 +030087 if (oe->numlower) {
88 type |= __OVL_PATH_ORIGIN;
89 if (d_is_dir(dentry))
90 type |= __OVL_PATH_MERGE;
91 }
Miklos Szeredibbb1e542016-12-16 11:02:56 +010092 } else {
93 if (oe->numlower > 1)
94 type |= __OVL_PATH_MERGE;
95 }
96 return type;
97}
98
99void ovl_path_upper(struct dentry *dentry, struct path *path)
100{
101 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
102 struct ovl_entry *oe = dentry->d_fsdata;
103
104 path->mnt = ofs->upper_mnt;
105 path->dentry = ovl_upperdentry_dereference(oe);
106}
107
108void ovl_path_lower(struct dentry *dentry, struct path *path)
109{
110 struct ovl_entry *oe = dentry->d_fsdata;
111
Kees Cook33006cd2017-03-29 14:02:19 -0700112 *path = oe->numlower ? oe->lowerstack[0] : (struct path) { };
Miklos Szeredibbb1e542016-12-16 11:02:56 +0100113}
114
115enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
116{
117 enum ovl_path_type type = ovl_path_type(dentry);
118
119 if (!OVL_TYPE_UPPER(type))
120 ovl_path_lower(dentry, path);
121 else
122 ovl_path_upper(dentry, path);
123
124 return type;
125}
126
127struct dentry *ovl_dentry_upper(struct dentry *dentry)
128{
129 struct ovl_entry *oe = dentry->d_fsdata;
130
131 return ovl_upperdentry_dereference(oe);
132}
133
134static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
135{
136 return oe->numlower ? oe->lowerstack[0].dentry : NULL;
137}
138
139struct dentry *ovl_dentry_lower(struct dentry *dentry)
140{
141 struct ovl_entry *oe = dentry->d_fsdata;
142
143 return __ovl_dentry_lower(oe);
144}
145
146struct dentry *ovl_dentry_real(struct dentry *dentry)
147{
148 struct ovl_entry *oe = dentry->d_fsdata;
149 struct dentry *realdentry;
150
151 realdentry = ovl_upperdentry_dereference(oe);
152 if (!realdentry)
153 realdentry = __ovl_dentry_lower(oe);
154
155 return realdentry;
156}
157
158struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
159{
160 struct ovl_entry *oe = dentry->d_fsdata;
161
162 return oe->cache;
163}
164
165void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
166{
167 struct ovl_entry *oe = dentry->d_fsdata;
168
169 oe->cache = cache;
170}
171
172bool ovl_dentry_is_opaque(struct dentry *dentry)
173{
174 struct ovl_entry *oe = dentry->d_fsdata;
175 return oe->opaque;
176}
177
Amir Goldsteinee1d6d372017-05-11 16:42:26 +0300178bool ovl_dentry_is_impure(struct dentry *dentry)
179{
180 struct ovl_entry *oe = dentry->d_fsdata;
181
182 return oe->impure;
183}
184
Miklos Szeredibbb1e542016-12-16 11:02:56 +0100185bool ovl_dentry_is_whiteout(struct dentry *dentry)
186{
187 return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
188}
189
Miklos Szeredi5cf5b472016-12-16 11:02:57 +0100190void ovl_dentry_set_opaque(struct dentry *dentry)
Miklos Szeredibbb1e542016-12-16 11:02:56 +0100191{
192 struct ovl_entry *oe = dentry->d_fsdata;
Miklos Szeredi5cf5b472016-12-16 11:02:57 +0100193
194 oe->opaque = true;
Miklos Szeredibbb1e542016-12-16 11:02:56 +0100195}
196
Miklos Szeredia6c60652016-12-16 11:02:56 +0100197bool ovl_redirect_dir(struct super_block *sb)
198{
199 struct ovl_fs *ofs = sb->s_fs_info;
200
Amir Goldstein21a22872017-05-17 00:12:41 +0300201 return ofs->config.redirect_dir && !ofs->noxattr;
Miklos Szeredia6c60652016-12-16 11:02:56 +0100202}
203
204const char *ovl_dentry_get_redirect(struct dentry *dentry)
205{
206 struct ovl_entry *oe = dentry->d_fsdata;
207
208 return oe->redirect;
209}
210
211void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
212{
213 struct ovl_entry *oe = dentry->d_fsdata;
214
215 kfree(oe->redirect);
216 oe->redirect = redirect;
217}
218
Miklos Szeredibbb1e542016-12-16 11:02:56 +0100219void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
220{
221 struct ovl_entry *oe = dentry->d_fsdata;
222
223 WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
224 WARN_ON(oe->__upperdentry);
225 /*
226 * Make sure upperdentry is consistent before making it visible to
227 * ovl_upperdentry_dereference().
228 */
229 smp_wmb();
230 oe->__upperdentry = upperdentry;
231}
232
233void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
234{
235 WRITE_ONCE(inode->i_private, (unsigned long) realinode |
236 (is_upper ? OVL_ISUPPER_MASK : 0));
237}
238
239void ovl_inode_update(struct inode *inode, struct inode *upperinode)
240{
241 WARN_ON(!upperinode);
242 WARN_ON(!inode_unhashed(inode));
243 WRITE_ONCE(inode->i_private,
244 (unsigned long) upperinode | OVL_ISUPPER_MASK);
245 if (!S_ISDIR(upperinode->i_mode))
246 __insert_inode_hash(inode, (unsigned long) upperinode);
247}
248
249void ovl_dentry_version_inc(struct dentry *dentry)
250{
251 struct ovl_entry *oe = dentry->d_fsdata;
252
253 WARN_ON(!inode_is_locked(dentry->d_inode));
254 oe->version++;
255}
256
257u64 ovl_dentry_version_get(struct dentry *dentry)
258{
259 struct ovl_entry *oe = dentry->d_fsdata;
260
261 WARN_ON(!inode_is_locked(dentry->d_inode));
262 return oe->version;
263}
264
265bool ovl_is_whiteout(struct dentry *dentry)
266{
267 struct inode *inode = dentry->d_inode;
268
269 return inode && IS_WHITEOUT(inode);
270}
271
272struct file *ovl_path_open(struct path *path, int flags)
273{
274 return dentry_open(path, flags | O_NOATIME, current_cred());
275}
Amir Goldstein39d3d602017-01-17 06:34:56 +0200276
277int ovl_copy_up_start(struct dentry *dentry)
278{
279 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
280 struct ovl_entry *oe = dentry->d_fsdata;
281 int err;
282
283 spin_lock(&ofs->copyup_wq.lock);
284 err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
285 if (!err) {
286 if (oe->__upperdentry)
287 err = 1; /* Already copied up */
288 else
289 oe->copying = true;
290 }
291 spin_unlock(&ofs->copyup_wq.lock);
292
293 return err;
294}
295
296void ovl_copy_up_end(struct dentry *dentry)
297{
298 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
299 struct ovl_entry *oe = dentry->d_fsdata;
300
301 spin_lock(&ofs->copyup_wq.lock);
302 oe->copying = false;
303 wake_up_locked(&ofs->copyup_wq);
304 spin_unlock(&ofs->copyup_wq.lock);
305}
Amir Goldstein82b749b2017-05-17 00:12:40 +0300306
Amir Goldsteinf3a15682017-05-24 15:29:33 +0300307bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
308{
309 int res;
310 char val;
311
312 if (!d_is_dir(dentry))
313 return false;
314
315 res = vfs_getxattr(dentry, name, &val, 1);
316 if (res == 1 && val == 'y')
317 return true;
318
319 return false;
320}
321
Amir Goldstein82b749b2017-05-17 00:12:40 +0300322int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
323 const char *name, const void *value, size_t size,
324 int xerr)
325{
326 int err;
327 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
328
329 if (ofs->noxattr)
330 return xerr;
331
332 err = ovl_do_setxattr(upperdentry, name, value, size, 0);
333
334 if (err == -EOPNOTSUPP) {
335 pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
336 ofs->noxattr = true;
337 return xerr;
338 }
339
340 return err;
341}
Amir Goldsteinf3a15682017-05-24 15:29:33 +0300342
343int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
344{
345 int err;
346 struct ovl_entry *oe = dentry->d_fsdata;
347
348 if (oe->impure)
349 return 0;
350
351 /*
352 * Do not fail when upper doesn't support xattrs.
353 * Upper inodes won't have origin nor redirect xattr anyway.
354 */
355 err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
356 "y", 1, 0);
357 if (!err)
358 oe->impure = true;
359
360 return err;
361}