]>
Commit | Line | Data |
---|---|---|
e9be9d5e MS |
1 | /* |
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 | ||
5b825c3a | 10 | #include <uapi/linux/magic.h> |
e9be9d5e MS |
11 | #include <linux/fs.h> |
12 | #include <linux/namei.h> | |
13 | #include <linux/xattr.h> | |
e9be9d5e | 14 | #include <linux/mount.h> |
e9be9d5e MS |
15 | #include <linux/parser.h> |
16 | #include <linux/module.h> | |
cc259639 | 17 | #include <linux/statfs.h> |
f45827e8 | 18 | #include <linux/seq_file.h> |
d837a49b | 19 | #include <linux/posix_acl_xattr.h> |
e9be9d5e MS |
20 | #include "overlayfs.h" |
21 | ||
22 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
23 | MODULE_DESCRIPTION("Overlay filesystem"); | |
24 | MODULE_LICENSE("GPL"); | |
25 | ||
e9be9d5e MS |
26 | |
27 | struct ovl_dir_cache; | |
28 | ||
a78d9f0d MS |
29 | #define OVL_MAX_STACK 500 |
30 | ||
688ea0e5 MS |
31 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
32 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); | |
33 | MODULE_PARM_DESC(ovl_redirect_dir_def, | |
34 | "Default to on or off for the redirect_dir feature"); | |
e9be9d5e | 35 | |
02bcd157 AG |
36 | static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); |
37 | module_param_named(index, ovl_index_def, bool, 0644); | |
38 | MODULE_PARM_DESC(ovl_index_def, | |
39 | "Default to on or off for the inodes index feature"); | |
40 | ||
e9be9d5e MS |
41 | static void ovl_dentry_release(struct dentry *dentry) |
42 | { | |
43 | struct ovl_entry *oe = dentry->d_fsdata; | |
44 | ||
45 | if (oe) { | |
dd662667 MS |
46 | unsigned int i; |
47 | ||
dd662667 MS |
48 | for (i = 0; i < oe->numlower; i++) |
49 | dput(oe->lowerstack[i].dentry); | |
e9be9d5e MS |
50 | kfree_rcu(oe, rcu); |
51 | } | |
52 | } | |
53 | ||
b0990fbb AG |
54 | static int ovl_check_append_only(struct inode *inode, int flag) |
55 | { | |
56 | /* | |
57 | * This test was moot in vfs may_open() because overlay inode does | |
58 | * not have the S_APPEND flag, so re-check on real upper inode | |
59 | */ | |
60 | if (IS_APPEND(inode)) { | |
61 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) | |
62 | return -EPERM; | |
63 | if (flag & O_TRUNC) | |
64 | return -EPERM; | |
65 | } | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
2d902671 MS |
70 | static struct dentry *ovl_d_real(struct dentry *dentry, |
71 | const struct inode *inode, | |
495e6429 | 72 | unsigned int open_flags, unsigned int flags) |
d101a125 MS |
73 | { |
74 | struct dentry *real; | |
b0990fbb | 75 | int err; |
d101a125 | 76 | |
cd91304e MS |
77 | if (flags & D_REAL_UPPER) |
78 | return ovl_dentry_upper(dentry); | |
79 | ||
ca4c8a3a | 80 | if (!d_is_reg(dentry)) { |
d101a125 MS |
81 | if (!inode || inode == d_inode(dentry)) |
82 | return dentry; | |
83 | goto bug; | |
84 | } | |
85 | ||
2d902671 | 86 | if (open_flags) { |
b0990fbb | 87 | err = ovl_open_maybe_copy_up(dentry, open_flags); |
2d902671 MS |
88 | if (err) |
89 | return ERR_PTR(err); | |
90 | } | |
91 | ||
d101a125 | 92 | real = ovl_dentry_upper(dentry); |
b0990fbb AG |
93 | if (real && (!inode || inode == d_inode(real))) { |
94 | if (!inode) { | |
95 | err = ovl_check_append_only(d_inode(real), open_flags); | |
96 | if (err) | |
97 | return ERR_PTR(err); | |
98 | } | |
d101a125 | 99 | return real; |
b0990fbb | 100 | } |
d101a125 MS |
101 | |
102 | real = ovl_dentry_lower(dentry); | |
103 | if (!real) | |
104 | goto bug; | |
105 | ||
c4fcfc16 | 106 | /* Handle recursion */ |
495e6429 | 107 | real = d_real(real, inode, open_flags, 0); |
c4fcfc16 | 108 | |
d101a125 MS |
109 | if (!inode || inode == d_inode(real)) |
110 | return real; | |
d101a125 | 111 | bug: |
656189d2 | 112 | WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, |
d101a125 MS |
113 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); |
114 | return dentry; | |
115 | } | |
116 | ||
7c03b5d4 MS |
117 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
118 | { | |
119 | struct ovl_entry *oe = dentry->d_fsdata; | |
120 | unsigned int i; | |
121 | int ret = 1; | |
122 | ||
123 | for (i = 0; i < oe->numlower; i++) { | |
124 | struct dentry *d = oe->lowerstack[i].dentry; | |
125 | ||
126 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
127 | ret = d->d_op->d_revalidate(d, flags); | |
128 | if (ret < 0) | |
129 | return ret; | |
130 | if (!ret) { | |
131 | if (!(flags & LOOKUP_RCU)) | |
132 | d_invalidate(d); | |
133 | return -ESTALE; | |
134 | } | |
135 | } | |
136 | } | |
137 | return 1; | |
138 | } | |
139 | ||
140 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
141 | { | |
142 | struct ovl_entry *oe = dentry->d_fsdata; | |
143 | unsigned int i; | |
144 | int ret = 1; | |
145 | ||
146 | for (i = 0; i < oe->numlower; i++) { | |
147 | struct dentry *d = oe->lowerstack[i].dentry; | |
148 | ||
149 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
150 | ret = d->d_op->d_weak_revalidate(d, flags); | |
151 | if (ret <= 0) | |
152 | break; | |
153 | } | |
154 | } | |
155 | return ret; | |
156 | } | |
157 | ||
e9be9d5e MS |
158 | static const struct dentry_operations ovl_dentry_operations = { |
159 | .d_release = ovl_dentry_release, | |
d101a125 | 160 | .d_real = ovl_d_real, |
e9be9d5e MS |
161 | }; |
162 | ||
7c03b5d4 MS |
163 | static const struct dentry_operations ovl_reval_dentry_operations = { |
164 | .d_release = ovl_dentry_release, | |
d101a125 | 165 | .d_real = ovl_d_real, |
7c03b5d4 MS |
166 | .d_revalidate = ovl_dentry_revalidate, |
167 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
168 | }; | |
169 | ||
13cf199d AG |
170 | static struct kmem_cache *ovl_inode_cachep; |
171 | ||
172 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
173 | { | |
174 | struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); | |
175 | ||
b3885bd6 HN |
176 | if (!oi) |
177 | return NULL; | |
178 | ||
04a01ac7 | 179 | oi->cache = NULL; |
cf31c463 | 180 | oi->redirect = NULL; |
04a01ac7 | 181 | oi->version = 0; |
13c72075 | 182 | oi->flags = 0; |
09d8b586 | 183 | oi->__upperdentry = NULL; |
25b7713a | 184 | oi->lower = NULL; |
a015dafc | 185 | mutex_init(&oi->lock); |
25b7713a | 186 | |
13cf199d AG |
187 | return &oi->vfs_inode; |
188 | } | |
189 | ||
190 | static void ovl_i_callback(struct rcu_head *head) | |
191 | { | |
192 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
193 | ||
194 | kmem_cache_free(ovl_inode_cachep, OVL_I(inode)); | |
195 | } | |
196 | ||
197 | static void ovl_destroy_inode(struct inode *inode) | |
198 | { | |
09d8b586 MS |
199 | struct ovl_inode *oi = OVL_I(inode); |
200 | ||
201 | dput(oi->__upperdentry); | |
cf31c463 | 202 | kfree(oi->redirect); |
4edb83bb | 203 | ovl_dir_cache_free(inode); |
a015dafc | 204 | mutex_destroy(&oi->lock); |
09d8b586 | 205 | |
13cf199d AG |
206 | call_rcu(&inode->i_rcu, ovl_i_callback); |
207 | } | |
208 | ||
a9075cdb | 209 | static void ovl_free_fs(struct ovl_fs *ufs) |
e9be9d5e | 210 | { |
dd662667 | 211 | unsigned i; |
e9be9d5e | 212 | |
02bcd157 | 213 | dput(ufs->indexdir); |
e9be9d5e | 214 | dput(ufs->workdir); |
85fdee1e AG |
215 | if (ufs->workdir_locked) |
216 | ovl_inuse_unlock(ufs->workbasedir); | |
2cac0c00 | 217 | dput(ufs->workbasedir); |
a9075cdb | 218 | if (ufs->upperdir_locked) |
2cac0c00 | 219 | ovl_inuse_unlock(ufs->upper_mnt->mnt_root); |
e9be9d5e | 220 | mntput(ufs->upper_mnt); |
2a9c6d06 | 221 | for (i = 0; i < ufs->numlower; i++) { |
b9343632 | 222 | mntput(ufs->lower_layers[i].mnt); |
2a9c6d06 CR |
223 | free_anon_bdev(ufs->lower_layers[i].pseudo_dev); |
224 | } | |
b9343632 | 225 | kfree(ufs->lower_layers); |
e9be9d5e | 226 | |
f45827e8 EZ |
227 | kfree(ufs->config.lowerdir); |
228 | kfree(ufs->config.upperdir); | |
229 | kfree(ufs->config.workdir); | |
a9075cdb MS |
230 | if (ufs->creator_cred) |
231 | put_cred(ufs->creator_cred); | |
e9be9d5e MS |
232 | kfree(ufs); |
233 | } | |
234 | ||
a9075cdb MS |
235 | static void ovl_put_super(struct super_block *sb) |
236 | { | |
237 | struct ovl_fs *ofs = sb->s_fs_info; | |
238 | ||
239 | ovl_free_fs(ofs); | |
240 | } | |
241 | ||
e593b2bf AG |
242 | static int ovl_sync_fs(struct super_block *sb, int wait) |
243 | { | |
244 | struct ovl_fs *ufs = sb->s_fs_info; | |
245 | struct super_block *upper_sb; | |
246 | int ret; | |
247 | ||
248 | if (!ufs->upper_mnt) | |
249 | return 0; | |
250 | upper_sb = ufs->upper_mnt->mnt_sb; | |
251 | if (!upper_sb->s_op->sync_fs) | |
252 | return 0; | |
253 | ||
254 | /* real inodes have already been synced by sync_filesystem(ovl_sb) */ | |
255 | down_read(&upper_sb->s_umount); | |
256 | ret = upper_sb->s_op->sync_fs(upper_sb, wait); | |
257 | up_read(&upper_sb->s_umount); | |
258 | return ret; | |
259 | } | |
260 | ||
cc259639 AW |
261 | /** |
262 | * ovl_statfs | |
263 | * @sb: The overlayfs super block | |
264 | * @buf: The struct kstatfs to fill in with stats | |
265 | * | |
266 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 267 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
268 | */ |
269 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
270 | { | |
271 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
272 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
273 | struct path path; | |
274 | int err; | |
275 | ||
4ebc5818 | 276 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
277 | |
278 | err = vfs_statfs(&path, buf); | |
279 | if (!err) { | |
6b2d5fe4 | 280 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
281 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
282 | } | |
283 | ||
284 | return err; | |
285 | } | |
286 | ||
02bcd157 AG |
287 | /* Will this overlay be forced to mount/remount ro? */ |
288 | static bool ovl_force_readonly(struct ovl_fs *ufs) | |
289 | { | |
290 | return (!ufs->upper_mnt || !ufs->workdir); | |
291 | } | |
292 | ||
f45827e8 EZ |
293 | /** |
294 | * ovl_show_options | |
295 | * | |
296 | * Prints the mount options for a given superblock. | |
297 | * Returns zero; does not fail. | |
298 | */ | |
299 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
300 | { | |
301 | struct super_block *sb = dentry->d_sb; | |
302 | struct ovl_fs *ufs = sb->s_fs_info; | |
303 | ||
a068acf2 | 304 | seq_show_option(m, "lowerdir", ufs->config.lowerdir); |
53a08cb9 | 305 | if (ufs->config.upperdir) { |
a068acf2 KC |
306 | seq_show_option(m, "upperdir", ufs->config.upperdir); |
307 | seq_show_option(m, "workdir", ufs->config.workdir); | |
53a08cb9 | 308 | } |
8d3095f4 MS |
309 | if (ufs->config.default_permissions) |
310 | seq_puts(m, ",default_permissions"); | |
c5bef3a7 AG |
311 | if (ufs->config.redirect_dir != ovl_redirect_dir_def) |
312 | seq_printf(m, ",redirect_dir=%s", | |
313 | ufs->config.redirect_dir ? "on" : "off"); | |
02bcd157 AG |
314 | if (ufs->config.index != ovl_index_def) |
315 | seq_printf(m, ",index=%s", | |
316 | ufs->config.index ? "on" : "off"); | |
f45827e8 EZ |
317 | return 0; |
318 | } | |
319 | ||
3cdf6fe9 SL |
320 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
321 | { | |
322 | struct ovl_fs *ufs = sb->s_fs_info; | |
323 | ||
02bcd157 | 324 | if (!(*flags & MS_RDONLY) && ovl_force_readonly(ufs)) |
3cdf6fe9 SL |
325 | return -EROFS; |
326 | ||
327 | return 0; | |
328 | } | |
329 | ||
e9be9d5e | 330 | static const struct super_operations ovl_super_operations = { |
13cf199d AG |
331 | .alloc_inode = ovl_alloc_inode, |
332 | .destroy_inode = ovl_destroy_inode, | |
333 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 334 | .put_super = ovl_put_super, |
e593b2bf | 335 | .sync_fs = ovl_sync_fs, |
cc259639 | 336 | .statfs = ovl_statfs, |
f45827e8 | 337 | .show_options = ovl_show_options, |
3cdf6fe9 | 338 | .remount_fs = ovl_remount, |
e9be9d5e MS |
339 | }; |
340 | ||
341 | enum { | |
342 | OPT_LOWERDIR, | |
343 | OPT_UPPERDIR, | |
344 | OPT_WORKDIR, | |
8d3095f4 | 345 | OPT_DEFAULT_PERMISSIONS, |
a6c60655 MS |
346 | OPT_REDIRECT_DIR_ON, |
347 | OPT_REDIRECT_DIR_OFF, | |
02bcd157 AG |
348 | OPT_INDEX_ON, |
349 | OPT_INDEX_OFF, | |
e9be9d5e MS |
350 | OPT_ERR, |
351 | }; | |
352 | ||
353 | static const match_table_t ovl_tokens = { | |
354 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
355 | {OPT_UPPERDIR, "upperdir=%s"}, | |
356 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 357 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
a6c60655 MS |
358 | {OPT_REDIRECT_DIR_ON, "redirect_dir=on"}, |
359 | {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"}, | |
02bcd157 AG |
360 | {OPT_INDEX_ON, "index=on"}, |
361 | {OPT_INDEX_OFF, "index=off"}, | |
e9be9d5e MS |
362 | {OPT_ERR, NULL} |
363 | }; | |
364 | ||
91c77947 MS |
365 | static char *ovl_next_opt(char **s) |
366 | { | |
367 | char *sbegin = *s; | |
368 | char *p; | |
369 | ||
370 | if (sbegin == NULL) | |
371 | return NULL; | |
372 | ||
373 | for (p = sbegin; *p; p++) { | |
374 | if (*p == '\\') { | |
375 | p++; | |
376 | if (!*p) | |
377 | break; | |
378 | } else if (*p == ',') { | |
379 | *p = '\0'; | |
380 | *s = p + 1; | |
381 | return sbegin; | |
382 | } | |
383 | } | |
384 | *s = NULL; | |
385 | return sbegin; | |
386 | } | |
387 | ||
e9be9d5e MS |
388 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
389 | { | |
390 | char *p; | |
391 | ||
91c77947 | 392 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
393 | int token; |
394 | substring_t args[MAX_OPT_ARGS]; | |
395 | ||
396 | if (!*p) | |
397 | continue; | |
398 | ||
399 | token = match_token(p, ovl_tokens, args); | |
400 | switch (token) { | |
401 | case OPT_UPPERDIR: | |
402 | kfree(config->upperdir); | |
403 | config->upperdir = match_strdup(&args[0]); | |
404 | if (!config->upperdir) | |
405 | return -ENOMEM; | |
406 | break; | |
407 | ||
408 | case OPT_LOWERDIR: | |
409 | kfree(config->lowerdir); | |
410 | config->lowerdir = match_strdup(&args[0]); | |
411 | if (!config->lowerdir) | |
412 | return -ENOMEM; | |
413 | break; | |
414 | ||
415 | case OPT_WORKDIR: | |
416 | kfree(config->workdir); | |
417 | config->workdir = match_strdup(&args[0]); | |
418 | if (!config->workdir) | |
419 | return -ENOMEM; | |
420 | break; | |
421 | ||
8d3095f4 MS |
422 | case OPT_DEFAULT_PERMISSIONS: |
423 | config->default_permissions = true; | |
424 | break; | |
425 | ||
a6c60655 MS |
426 | case OPT_REDIRECT_DIR_ON: |
427 | config->redirect_dir = true; | |
428 | break; | |
429 | ||
430 | case OPT_REDIRECT_DIR_OFF: | |
431 | config->redirect_dir = false; | |
432 | break; | |
433 | ||
02bcd157 AG |
434 | case OPT_INDEX_ON: |
435 | config->index = true; | |
436 | break; | |
437 | ||
438 | case OPT_INDEX_OFF: | |
439 | config->index = false; | |
440 | break; | |
441 | ||
e9be9d5e | 442 | default: |
bead55ef | 443 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
444 | return -EINVAL; |
445 | } | |
446 | } | |
71cbad7e | 447 | |
448 | /* Workdir is useless in non-upper mount */ | |
449 | if (!config->upperdir && config->workdir) { | |
450 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
451 | config->workdir); | |
452 | kfree(config->workdir); | |
453 | config->workdir = NULL; | |
454 | } | |
455 | ||
e9be9d5e MS |
456 | return 0; |
457 | } | |
458 | ||
459 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 460 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 461 | |
6e88256e | 462 | static struct dentry *ovl_workdir_create(struct ovl_fs *ufs, |
6b8aa129 | 463 | const char *name, bool persist) |
e9be9d5e | 464 | { |
6e88256e | 465 | struct inode *dir = ufs->workbasedir->d_inode; |
6b8aa129 | 466 | struct vfsmount *mnt = ufs->upper_mnt; |
e9be9d5e MS |
467 | struct dentry *work; |
468 | int err; | |
469 | bool retried = false; | |
6b8aa129 | 470 | bool locked = false; |
e9be9d5e MS |
471 | |
472 | err = mnt_want_write(mnt); | |
473 | if (err) | |
6b8aa129 | 474 | goto out_err; |
e9be9d5e | 475 | |
5955102c | 476 | inode_lock_nested(dir, I_MUTEX_PARENT); |
6b8aa129 AG |
477 | locked = true; |
478 | ||
e9be9d5e | 479 | retry: |
6e88256e | 480 | work = lookup_one_len(name, ufs->workbasedir, strlen(name)); |
e9be9d5e MS |
481 | |
482 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
483 | struct iattr attr = { |
484 | .ia_valid = ATTR_MODE, | |
32a3d848 | 485 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 486 | }; |
e9be9d5e MS |
487 | |
488 | if (work->d_inode) { | |
489 | err = -EEXIST; | |
490 | if (retried) | |
491 | goto out_dput; | |
492 | ||
6b8aa129 AG |
493 | if (persist) |
494 | goto out_unlock; | |
495 | ||
e9be9d5e | 496 | retried = true; |
eea2fb48 | 497 | ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e MS |
498 | dput(work); |
499 | goto retry; | |
500 | } | |
501 | ||
32a3d848 AV |
502 | err = ovl_create_real(dir, work, |
503 | &(struct cattr){.mode = S_IFDIR | 0}, | |
504 | NULL, true); | |
e9be9d5e MS |
505 | if (err) |
506 | goto out_dput; | |
c11b9fdd | 507 | |
cb348edb MS |
508 | /* |
509 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
510 | * | |
511 | * a) success (there was a POSIX ACL xattr and was removed) | |
512 | * b) -ENODATA (there was no POSIX ACL xattr) | |
513 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
514 | * | |
515 | * There are various other error values that could effectively | |
516 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
517 | * if the xattr name is too long), but the set of filesystems | |
518 | * allowed as upper are limited to "normal" ones, where checking | |
519 | * for the above two errors is sufficient. | |
520 | */ | |
c11b9fdd | 521 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 522 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
523 | goto out_dput; |
524 | ||
525 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 526 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
527 | goto out_dput; |
528 | ||
529 | /* Clear any inherited mode bits */ | |
530 | inode_lock(work->d_inode); | |
531 | err = notify_change(work, &attr, NULL); | |
532 | inode_unlock(work->d_inode); | |
533 | if (err) | |
534 | goto out_dput; | |
6b8aa129 AG |
535 | } else { |
536 | err = PTR_ERR(work); | |
537 | goto out_err; | |
e9be9d5e MS |
538 | } |
539 | out_unlock: | |
e9be9d5e | 540 | mnt_drop_write(mnt); |
6b8aa129 AG |
541 | if (locked) |
542 | inode_unlock(dir); | |
e9be9d5e MS |
543 | |
544 | return work; | |
545 | ||
546 | out_dput: | |
547 | dput(work); | |
6b8aa129 AG |
548 | out_err: |
549 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", | |
550 | ufs->config.workdir, name, -err); | |
6b8aa129 | 551 | work = NULL; |
e9be9d5e MS |
552 | goto out_unlock; |
553 | } | |
554 | ||
91c77947 MS |
555 | static void ovl_unescape(char *s) |
556 | { | |
557 | char *d = s; | |
558 | ||
559 | for (;; s++, d++) { | |
560 | if (*s == '\\') | |
561 | s++; | |
562 | *d = *s; | |
563 | if (!*s) | |
564 | break; | |
565 | } | |
566 | } | |
567 | ||
ab508822 MS |
568 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
569 | { | |
a78d9f0d | 570 | int err = -EINVAL; |
ab508822 | 571 | |
a78d9f0d MS |
572 | if (!*name) { |
573 | pr_err("overlayfs: empty lowerdir\n"); | |
574 | goto out; | |
575 | } | |
ab508822 MS |
576 | err = kern_path(name, LOOKUP_FOLLOW, path); |
577 | if (err) { | |
578 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
579 | goto out; | |
580 | } | |
581 | err = -EINVAL; | |
7c03b5d4 | 582 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
583 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
584 | goto out_put; | |
585 | } | |
2b8c30e9 | 586 | if (!d_is_dir(path->dentry)) { |
ab508822 MS |
587 | pr_err("overlayfs: '%s' not a directory\n", name); |
588 | goto out_put; | |
589 | } | |
590 | return 0; | |
591 | ||
592 | out_put: | |
8aafcb59 | 593 | path_put_init(path); |
ab508822 MS |
594 | out: |
595 | return err; | |
596 | } | |
597 | ||
598 | static int ovl_mount_dir(const char *name, struct path *path) | |
599 | { | |
600 | int err = -ENOMEM; | |
601 | char *tmp = kstrdup(name, GFP_KERNEL); | |
602 | ||
603 | if (tmp) { | |
604 | ovl_unescape(tmp); | |
605 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
606 | |
607 | if (!err) | |
608 | if (ovl_dentry_remote(path->dentry)) { | |
609 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
610 | tmp); | |
8aafcb59 | 611 | path_put_init(path); |
7c03b5d4 MS |
612 | err = -EINVAL; |
613 | } | |
ab508822 MS |
614 | kfree(tmp); |
615 | } | |
616 | return err; | |
617 | } | |
618 | ||
6b2d5fe4 MS |
619 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
620 | const char *name) | |
ab508822 | 621 | { |
ab508822 | 622 | struct kstatfs statfs; |
6b2d5fe4 MS |
623 | int err = vfs_statfs(path, &statfs); |
624 | ||
625 | if (err) | |
626 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
627 | else | |
628 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
629 | ||
630 | return err; | |
631 | } | |
632 | ||
633 | static int ovl_lower_dir(const char *name, struct path *path, | |
634 | struct ovl_fs *ofs, int *stack_depth, bool *remote) | |
635 | { | |
636 | int err; | |
ab508822 | 637 | |
a78d9f0d | 638 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
639 | if (err) |
640 | goto out; | |
641 | ||
6b2d5fe4 MS |
642 | err = ovl_check_namelen(path, ofs, name); |
643 | if (err) | |
ab508822 | 644 | goto out_put; |
6b2d5fe4 | 645 | |
ab508822 MS |
646 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
647 | ||
7c03b5d4 MS |
648 | if (ovl_dentry_remote(path->dentry)) |
649 | *remote = true; | |
650 | ||
02bcd157 AG |
651 | /* |
652 | * The inodes index feature needs to encode and decode file | |
653 | * handles, so it requires that all layers support them. | |
654 | */ | |
655 | if (ofs->config.index && !ovl_can_decode_fh(path->dentry->d_sb)) { | |
656 | ofs->config.index = false; | |
657 | pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off.\n", name); | |
658 | } | |
659 | ||
ab508822 MS |
660 | return 0; |
661 | ||
662 | out_put: | |
8aafcb59 | 663 | path_put_init(path); |
ab508822 MS |
664 | out: |
665 | return err; | |
666 | } | |
667 | ||
e9be9d5e MS |
668 | /* Workdir should not be subdir of upperdir and vice versa */ |
669 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
670 | { | |
671 | bool ok = false; | |
672 | ||
673 | if (workdir != upperdir) { | |
674 | ok = (lock_rename(workdir, upperdir) == NULL); | |
675 | unlock_rename(workdir, upperdir); | |
676 | } | |
677 | return ok; | |
678 | } | |
679 | ||
a78d9f0d MS |
680 | static unsigned int ovl_split_lowerdirs(char *str) |
681 | { | |
682 | unsigned int ctr = 1; | |
683 | char *s, *d; | |
684 | ||
685 | for (s = d = str;; s++, d++) { | |
686 | if (*s == '\\') { | |
687 | s++; | |
688 | } else if (*s == ':') { | |
689 | *d = '\0'; | |
690 | ctr++; | |
691 | continue; | |
692 | } | |
693 | *d = *s; | |
694 | if (!*s) | |
695 | break; | |
696 | } | |
697 | return ctr; | |
698 | } | |
699 | ||
0eb45fc3 AG |
700 | static int __maybe_unused |
701 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
702 | struct dentry *dentry, struct inode *inode, | |
703 | const char *name, void *buffer, size_t size) | |
704 | { | |
1d88f183 | 705 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
0eb45fc3 AG |
706 | } |
707 | ||
0c97be22 AG |
708 | static int __maybe_unused |
709 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
710 | struct dentry *dentry, struct inode *inode, | |
711 | const char *name, const void *value, | |
712 | size_t size, int flags) | |
d837a49b MS |
713 | { |
714 | struct dentry *workdir = ovl_workdir(dentry); | |
09d8b586 | 715 | struct inode *realinode = ovl_inode_real(inode); |
d837a49b MS |
716 | struct posix_acl *acl = NULL; |
717 | int err; | |
718 | ||
719 | /* Check that everything is OK before copy-up */ | |
720 | if (value) { | |
721 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
722 | if (IS_ERR(acl)) | |
723 | return PTR_ERR(acl); | |
724 | } | |
725 | err = -EOPNOTSUPP; | |
726 | if (!IS_POSIXACL(d_inode(workdir))) | |
727 | goto out_acl_release; | |
728 | if (!realinode->i_op->set_acl) | |
729 | goto out_acl_release; | |
730 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
731 | err = acl ? -EACCES : 0; | |
732 | goto out_acl_release; | |
733 | } | |
734 | err = -EPERM; | |
735 | if (!inode_owner_or_capable(inode)) | |
736 | goto out_acl_release; | |
737 | ||
738 | posix_acl_release(acl); | |
739 | ||
fd3220d3 MS |
740 | /* |
741 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
742 | * be done with mounter's capabilities and so that won't do it for us). | |
743 | */ | |
744 | if (unlikely(inode->i_mode & S_ISGID) && | |
745 | handler->flags == ACL_TYPE_ACCESS && | |
746 | !in_group_p(inode->i_gid) && | |
747 | !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { | |
748 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; | |
749 | ||
750 | err = ovl_setattr(dentry, &iattr); | |
751 | if (err) | |
752 | return err; | |
753 | } | |
754 | ||
1d88f183 | 755 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
ce31513a | 756 | if (!err) |
09d8b586 | 757 | ovl_copyattr(ovl_inode_real(inode), inode); |
ce31513a MS |
758 | |
759 | return err; | |
d837a49b MS |
760 | |
761 | out_acl_release: | |
762 | posix_acl_release(acl); | |
763 | return err; | |
764 | } | |
765 | ||
0eb45fc3 AG |
766 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
767 | struct dentry *dentry, struct inode *inode, | |
768 | const char *name, void *buffer, size_t size) | |
769 | { | |
48fab5d7 | 770 | return -EOPNOTSUPP; |
0eb45fc3 AG |
771 | } |
772 | ||
d837a49b MS |
773 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
774 | struct dentry *dentry, struct inode *inode, | |
775 | const char *name, const void *value, | |
776 | size_t size, int flags) | |
777 | { | |
48fab5d7 | 778 | return -EOPNOTSUPP; |
d837a49b MS |
779 | } |
780 | ||
0eb45fc3 AG |
781 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
782 | struct dentry *dentry, struct inode *inode, | |
783 | const char *name, void *buffer, size_t size) | |
784 | { | |
1d88f183 | 785 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
786 | } |
787 | ||
0e585ccc AG |
788 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
789 | struct dentry *dentry, struct inode *inode, | |
790 | const char *name, const void *value, | |
791 | size_t size, int flags) | |
792 | { | |
1d88f183 | 793 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
794 | } |
795 | ||
0c97be22 AG |
796 | static const struct xattr_handler __maybe_unused |
797 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
798 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
799 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 800 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
801 | .set = ovl_posix_acl_xattr_set, |
802 | }; | |
803 | ||
0c97be22 AG |
804 | static const struct xattr_handler __maybe_unused |
805 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
806 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
807 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 808 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
809 | .set = ovl_posix_acl_xattr_set, |
810 | }; | |
811 | ||
812 | static const struct xattr_handler ovl_own_xattr_handler = { | |
813 | .prefix = OVL_XATTR_PREFIX, | |
0eb45fc3 | 814 | .get = ovl_own_xattr_get, |
d837a49b MS |
815 | .set = ovl_own_xattr_set, |
816 | }; | |
817 | ||
818 | static const struct xattr_handler ovl_other_xattr_handler = { | |
819 | .prefix = "", /* catch all */ | |
0eb45fc3 | 820 | .get = ovl_other_xattr_get, |
d837a49b MS |
821 | .set = ovl_other_xattr_set, |
822 | }; | |
823 | ||
824 | static const struct xattr_handler *ovl_xattr_handlers[] = { | |
0c97be22 | 825 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
826 | &ovl_posix_acl_access_xattr_handler, |
827 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 828 | #endif |
d837a49b MS |
829 | &ovl_own_xattr_handler, |
830 | &ovl_other_xattr_handler, | |
831 | NULL | |
832 | }; | |
833 | ||
6ee8acf0 MS |
834 | static int ovl_get_upperpath(struct ovl_fs *ufs, struct path *upperpath) |
835 | { | |
836 | int err; | |
837 | ||
838 | err = ovl_mount_dir(ufs->config.upperdir, upperpath); | |
839 | if (err) | |
840 | goto out; | |
841 | ||
842 | /* Upper fs should not be r/o */ | |
843 | if (sb_rdonly(upperpath->mnt->mnt_sb)) { | |
844 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
845 | err = -EINVAL; | |
846 | goto out; | |
847 | } | |
848 | ||
849 | err = ovl_check_namelen(upperpath, ufs, ufs->config.upperdir); | |
850 | if (err) | |
851 | goto out; | |
852 | ||
853 | err = -EBUSY; | |
854 | if (ovl_inuse_trylock(upperpath->dentry)) { | |
855 | ufs->upperdir_locked = true; | |
856 | } else if (ufs->config.index) { | |
857 | pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n"); | |
858 | goto out; | |
859 | } else { | |
860 | pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
861 | } | |
862 | err = 0; | |
863 | out: | |
864 | return err; | |
865 | } | |
866 | ||
6e88256e | 867 | static int ovl_get_workdir(struct ovl_fs *ufs, struct path *workpath) |
8ed61dc3 MS |
868 | { |
869 | struct dentry *temp; | |
870 | int err; | |
871 | ||
6e88256e | 872 | ufs->workdir = ovl_workdir_create(ufs, OVL_WORKDIR_NAME, false); |
8ed61dc3 MS |
873 | if (!ufs->workdir) |
874 | return 0; | |
875 | ||
876 | /* | |
877 | * Upper should support d_type, else whiteouts are visible. Given | |
878 | * workdir and upper are on same fs, we can do iterate_dir() on | |
879 | * workdir. This check requires successful creation of workdir in | |
880 | * previous step. | |
881 | */ | |
882 | err = ovl_check_d_type_supported(workpath); | |
883 | if (err < 0) | |
884 | return err; | |
885 | ||
886 | /* | |
887 | * We allowed this configuration and don't want to break users over | |
888 | * kernel upgrade. So warn instead of erroring out. | |
889 | */ | |
890 | if (!err) | |
891 | pr_warn("overlayfs: upper fs needs to support d_type.\n"); | |
892 | ||
893 | /* Check if upper/work fs supports O_TMPFILE */ | |
894 | temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0); | |
895 | ufs->tmpfile = !IS_ERR(temp); | |
896 | if (ufs->tmpfile) | |
897 | dput(temp); | |
898 | else | |
899 | pr_warn("overlayfs: upper fs does not support tmpfile.\n"); | |
900 | ||
901 | /* | |
902 | * Check if upper/work fs supports trusted.overlay.* xattr | |
903 | */ | |
904 | err = ovl_do_setxattr(ufs->workdir, OVL_XATTR_OPAQUE, "0", 1, 0); | |
905 | if (err) { | |
906 | ufs->noxattr = true; | |
907 | pr_warn("overlayfs: upper fs does not support xattr.\n"); | |
908 | } else { | |
909 | vfs_removexattr(ufs->workdir, OVL_XATTR_OPAQUE); | |
910 | } | |
911 | ||
912 | /* Check if upper/work fs supports file handles */ | |
913 | if (ufs->config.index && | |
914 | !ovl_can_decode_fh(ufs->workdir->d_sb)) { | |
915 | ufs->config.index = false; | |
916 | pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); | |
917 | } | |
918 | ||
919 | return 0; | |
920 | } | |
921 | ||
520d7c86 MS |
922 | static int ovl_get_workpath(struct ovl_fs *ufs, struct path *upperpath, |
923 | struct path *workpath) | |
924 | { | |
925 | int err; | |
926 | ||
927 | err = ovl_mount_dir(ufs->config.workdir, workpath); | |
928 | if (err) | |
929 | goto out; | |
930 | ||
931 | err = -EINVAL; | |
932 | if (upperpath->mnt != workpath->mnt) { | |
933 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); | |
934 | goto out; | |
935 | } | |
936 | if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) { | |
937 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); | |
938 | goto out; | |
939 | } | |
940 | ||
941 | err = -EBUSY; | |
942 | if (ovl_inuse_trylock(workpath->dentry)) { | |
943 | ufs->workdir_locked = true; | |
944 | } else if (ufs->config.index) { | |
945 | pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n"); | |
946 | goto out; | |
947 | } else { | |
948 | pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
949 | } | |
950 | ||
951 | ufs->workbasedir = dget(workpath->dentry); | |
952 | err = 0; | |
953 | out: | |
954 | return err; | |
955 | } | |
956 | ||
957 | static int ovl_get_upper(struct ovl_fs *ufs, struct path *upperpath) | |
958 | { | |
959 | struct vfsmount *upper_mnt; | |
960 | ||
961 | upper_mnt = clone_private_mount(upperpath); | |
962 | if (IS_ERR(upper_mnt)) { | |
963 | pr_err("overlayfs: failed to clone upperpath\n"); | |
964 | return PTR_ERR(upper_mnt); | |
965 | } | |
966 | ||
967 | /* Don't inherit atime flags */ | |
968 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
969 | ufs->upper_mnt = upper_mnt; | |
970 | ||
971 | return 0; | |
972 | } | |
973 | ||
6e88256e | 974 | static int ovl_get_indexdir(struct ovl_fs *ufs, struct ovl_entry *oe, |
95e6d417 | 975 | struct path *upperpath) |
f7e3a7d9 MS |
976 | { |
977 | int err; | |
978 | ||
979 | /* Verify lower root is upper root origin */ | |
980 | err = ovl_verify_origin(upperpath->dentry, | |
981 | oe->lowerstack[0].layer->mnt, | |
982 | oe->lowerstack[0].dentry, | |
983 | false, true); | |
984 | if (err) { | |
985 | pr_err("overlayfs: failed to verify upper root origin\n"); | |
986 | goto out; | |
987 | } | |
988 | ||
6e88256e | 989 | ufs->indexdir = ovl_workdir_create(ufs, OVL_INDEXDIR_NAME, true); |
f7e3a7d9 MS |
990 | if (ufs->indexdir) { |
991 | /* Verify upper root is index dir origin */ | |
992 | err = ovl_verify_origin(ufs->indexdir, ufs->upper_mnt, | |
993 | upperpath->dentry, true, true); | |
994 | if (err) | |
995 | pr_err("overlayfs: failed to verify index dir origin\n"); | |
996 | ||
997 | /* Cleanup bad/stale/orphan index entries */ | |
998 | if (!err) | |
999 | err = ovl_indexdir_cleanup(ufs->indexdir, | |
1000 | ufs->upper_mnt, | |
1001 | oe->lowerstack, | |
1002 | oe->numlower); | |
1003 | } | |
1004 | if (err || !ufs->indexdir) | |
1005 | pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); | |
1006 | ||
1007 | out: | |
1008 | return err; | |
1009 | } | |
1010 | ||
520d7c86 MS |
1011 | static int ovl_get_lower_layers(struct ovl_fs *ufs, struct path *stack, |
1012 | unsigned int numlower) | |
1013 | { | |
1014 | int err; | |
1015 | unsigned int i; | |
1016 | ||
1017 | err = -ENOMEM; | |
1018 | ufs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer), | |
1019 | GFP_KERNEL); | |
1020 | if (ufs->lower_layers == NULL) | |
1021 | goto out; | |
1022 | for (i = 0; i < numlower; i++) { | |
1023 | struct vfsmount *mnt; | |
1024 | dev_t dev; | |
1025 | ||
1026 | err = get_anon_bdev(&dev); | |
1027 | if (err) { | |
1028 | pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n"); | |
1029 | goto out; | |
1030 | } | |
1031 | ||
1032 | mnt = clone_private_mount(&stack[i]); | |
1033 | err = PTR_ERR(mnt); | |
1034 | if (IS_ERR(mnt)) { | |
1035 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
1036 | free_anon_bdev(dev); | |
1037 | goto out; | |
1038 | } | |
1039 | /* | |
1040 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1041 | * will fail instead of modifying lower fs. | |
1042 | */ | |
1043 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1044 | ||
1045 | ufs->lower_layers[ufs->numlower].mnt = mnt; | |
1046 | ufs->lower_layers[ufs->numlower].pseudo_dev = dev; | |
1047 | ufs->numlower++; | |
1048 | ||
1049 | /* Check if all lower layers are on same sb */ | |
1050 | if (i == 0) | |
1051 | ufs->same_sb = mnt->mnt_sb; | |
1052 | else if (ufs->same_sb != mnt->mnt_sb) | |
1053 | ufs->same_sb = NULL; | |
1054 | } | |
1055 | err = 0; | |
1056 | out: | |
1057 | return err; | |
1058 | } | |
1059 | ||
53dbb0b4 MS |
1060 | static int ovl_get_lowerstack(struct super_block *sb, struct ovl_fs *ufs, |
1061 | struct path **stackp, unsigned int *stacklenp) | |
1062 | { | |
1063 | int err; | |
1064 | char *lowertmp, *lower; | |
1065 | struct path *stack; | |
1066 | unsigned int stacklen, numlower, i; | |
1067 | bool remote = false; | |
1068 | ||
1069 | err = -ENOMEM; | |
1070 | lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL); | |
1071 | if (!lowertmp) | |
1072 | goto out; | |
1073 | ||
1074 | err = -EINVAL; | |
1075 | stacklen = ovl_split_lowerdirs(lowertmp); | |
1076 | if (stacklen > OVL_MAX_STACK) { | |
1077 | pr_err("overlayfs: too many lower directories, limit is %d\n", | |
1078 | OVL_MAX_STACK); | |
1079 | goto out; | |
1080 | } else if (!ufs->config.upperdir && stacklen == 1) { | |
1081 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); | |
1082 | goto out; | |
1083 | } | |
1084 | ||
1085 | err = -ENOMEM; | |
1086 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
1087 | if (!stack) | |
1088 | goto out; | |
1089 | ||
1090 | err = -EINVAL; | |
1091 | lower = lowertmp; | |
1092 | for (numlower = 0; numlower < stacklen; numlower++) { | |
1093 | err = ovl_lower_dir(lower, &stack[numlower], ufs, | |
1094 | &sb->s_stack_depth, &remote); | |
1095 | if (err) | |
1096 | goto out_free_stack; | |
1097 | ||
1098 | lower = strchr(lower, '\0') + 1; | |
1099 | } | |
1100 | ||
1101 | err = -EINVAL; | |
1102 | sb->s_stack_depth++; | |
1103 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1104 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
1105 | goto out_free_stack; | |
1106 | } | |
1107 | ||
1108 | *stackp = stack; | |
1109 | *stacklenp = numlower; | |
1110 | ||
1111 | if (remote) | |
1112 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1113 | else | |
1114 | sb->s_d_op = &ovl_dentry_operations; | |
1115 | ||
1116 | err = 0; | |
1117 | ||
1118 | out: | |
1119 | kfree(lowertmp); | |
1120 | return err; | |
1121 | ||
1122 | out_free_stack: | |
1123 | for (i = 0; i < numlower; i++) | |
1124 | path_put(&stack[i]); | |
1125 | kfree(stack); | |
1126 | goto out; | |
1127 | } | |
1128 | ||
e9be9d5e MS |
1129 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1130 | { | |
33006cdf KC |
1131 | struct path upperpath = { }; |
1132 | struct path workpath = { }; | |
e9be9d5e | 1133 | struct dentry *root_dentry; |
a9075cdb | 1134 | struct ovl_entry *oe = NULL; |
e9be9d5e | 1135 | struct ovl_fs *ufs; |
a78d9f0d | 1136 | struct path *stack = NULL; |
53dbb0b4 | 1137 | unsigned int numlower = 0; |
dd662667 | 1138 | unsigned int i; |
51f8f3c4 | 1139 | struct cred *cred; |
e9be9d5e MS |
1140 | int err; |
1141 | ||
f45827e8 EZ |
1142 | err = -ENOMEM; |
1143 | ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); | |
1144 | if (!ufs) | |
e9be9d5e MS |
1145 | goto out; |
1146 | ||
c6fe6254 MS |
1147 | ufs->creator_cred = cred = prepare_creds(); |
1148 | if (!cred) | |
1149 | goto out_err; | |
1150 | ||
688ea0e5 | 1151 | ufs->config.redirect_dir = ovl_redirect_dir_def; |
02bcd157 | 1152 | ufs->config.index = ovl_index_def; |
f45827e8 EZ |
1153 | err = ovl_parse_opt((char *) data, &ufs->config); |
1154 | if (err) | |
a9075cdb | 1155 | goto out_err; |
f45827e8 | 1156 | |
e9be9d5e | 1157 | err = -EINVAL; |
53a08cb9 | 1158 | if (!ufs->config.lowerdir) { |
07f2af7b KK |
1159 | if (!silent) |
1160 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
a9075cdb | 1161 | goto out_err; |
e9be9d5e MS |
1162 | } |
1163 | ||
53a08cb9 | 1164 | sb->s_stack_depth = 0; |
cf9a6784 | 1165 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
53a08cb9 | 1166 | if (ufs->config.upperdir) { |
53a08cb9 MS |
1167 | if (!ufs->config.workdir) { |
1168 | pr_err("overlayfs: missing 'workdir'\n"); | |
a9075cdb | 1169 | goto out_err; |
53a08cb9 | 1170 | } |
e9be9d5e | 1171 | |
6ee8acf0 | 1172 | err = ovl_get_upperpath(ufs, &upperpath); |
53a08cb9 | 1173 | if (err) |
a9075cdb | 1174 | goto out_err; |
2cac0c00 | 1175 | |
c6fe6254 | 1176 | err = ovl_get_upper(ufs, &upperpath); |
53a08cb9 | 1177 | if (err) |
a9075cdb | 1178 | goto out_err; |
2cac0c00 | 1179 | |
c6fe6254 | 1180 | err = ovl_get_workpath(ufs, &upperpath, &workpath); |
21a3b317 | 1181 | if (err) |
a9075cdb | 1182 | goto out_err; |
d719e8f2 | 1183 | |
6e88256e | 1184 | err = ovl_get_workdir(ufs, &workpath); |
8ed61dc3 | 1185 | if (err) |
a9075cdb | 1186 | goto out_err; |
c6fe6254 | 1187 | |
6e88256e MS |
1188 | if (!ufs->workdir) |
1189 | sb->s_flags |= MS_RDONLY; | |
1190 | ||
c6fe6254 MS |
1191 | sb->s_stack_depth = ufs->upper_mnt->mnt_sb->s_stack_depth; |
1192 | sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran; | |
1193 | ||
e9be9d5e | 1194 | } |
c6fe6254 MS |
1195 | err = ovl_get_lowerstack(sb, ufs, &stack, &numlower); |
1196 | if (err) | |
1197 | goto out_err; | |
e9be9d5e | 1198 | |
c0d91fb9 MS |
1199 | err = ovl_get_lower_layers(ufs, stack, numlower); |
1200 | if (err) | |
a9075cdb | 1201 | goto out_err; |
e9be9d5e | 1202 | |
71cbad7e | 1203 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
1204 | if (!ufs->upper_mnt) | |
e9be9d5e | 1205 | sb->s_flags |= MS_RDONLY; |
7bcd74b9 AG |
1206 | else if (ufs->upper_mnt->mnt_sb != ufs->same_sb) |
1207 | ufs->same_sb = NULL; | |
e9be9d5e | 1208 | |
b9343632 CR |
1209 | err = -ENOMEM; |
1210 | oe = ovl_alloc_entry(numlower); | |
1211 | if (!oe) | |
a9075cdb | 1212 | goto out_err; |
b9343632 CR |
1213 | |
1214 | for (i = 0; i < numlower; i++) { | |
1215 | oe->lowerstack[i].dentry = stack[i].dentry; | |
1216 | oe->lowerstack[i].layer = &(ufs->lower_layers[i]); | |
1217 | } | |
1218 | ||
02bcd157 | 1219 | if (!(ovl_force_readonly(ufs)) && ufs->config.index) { |
6e88256e | 1220 | err = ovl_get_indexdir(ufs, oe, &upperpath); |
54fb347e | 1221 | if (err) |
a9075cdb | 1222 | goto out_err; |
6e88256e MS |
1223 | |
1224 | if (!ufs->indexdir) | |
1225 | sb->s_flags |= MS_RDONLY; | |
02bcd157 AG |
1226 | } |
1227 | ||
1228 | /* Show index=off/on in /proc/mounts for any of the reasons above */ | |
1229 | if (!ufs->indexdir) | |
1230 | ufs->config.index = false; | |
1231 | ||
51f8f3c4 KK |
1232 | /* Never override disk quota limits or use reserved space */ |
1233 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1234 | ||
655042cc VG |
1235 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
1236 | sb->s_op = &ovl_super_operations; | |
1237 | sb->s_xattr = ovl_xattr_handlers; | |
1238 | sb->s_fs_info = ufs; | |
1239 | sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK; | |
1240 | ||
c6fe6254 | 1241 | err = -ENOMEM; |
ca4c8a3a | 1242 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); |
e9be9d5e | 1243 | if (!root_dentry) |
a9075cdb | 1244 | goto out_err; |
e9be9d5e MS |
1245 | |
1246 | mntput(upperpath.mnt); | |
a78d9f0d MS |
1247 | for (i = 0; i < numlower; i++) |
1248 | mntput(stack[i].mnt); | |
b9343632 | 1249 | kfree(stack); |
95e6d417 | 1250 | path_put(&workpath); |
e9be9d5e | 1251 | |
f3a15685 | 1252 | if (upperpath.dentry) { |
55acc661 | 1253 | oe->has_upper = true; |
13c72075 MS |
1254 | if (ovl_is_impuredir(upperpath.dentry)) |
1255 | ovl_set_flag(OVL_IMPURE, d_inode(root_dentry)); | |
f3a15685 | 1256 | } |
e9be9d5e MS |
1257 | |
1258 | root_dentry->d_fsdata = oe; | |
1259 | ||
b79e05aa AG |
1260 | /* Root is always merge -> can have whiteouts */ |
1261 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root_dentry)); | |
09d8b586 MS |
1262 | ovl_inode_init(d_inode(root_dentry), upperpath.dentry, |
1263 | ovl_dentry_lower(root_dentry)); | |
ed06e069 | 1264 | |
e9be9d5e | 1265 | sb->s_root = root_dentry; |
e9be9d5e MS |
1266 | |
1267 | return 0; | |
1268 | ||
a9075cdb | 1269 | out_err: |
b9343632 | 1270 | kfree(oe); |
a78d9f0d MS |
1271 | for (i = 0; i < numlower; i++) |
1272 | path_put(&stack[i]); | |
1273 | kfree(stack); | |
3b7a9a24 | 1274 | path_put(&workpath); |
e9be9d5e | 1275 | path_put(&upperpath); |
a9075cdb | 1276 | ovl_free_fs(ufs); |
e9be9d5e MS |
1277 | out: |
1278 | return err; | |
1279 | } | |
1280 | ||
1281 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1282 | const char *dev_name, void *raw_data) | |
1283 | { | |
1284 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1285 | } | |
1286 | ||
1287 | static struct file_system_type ovl_fs_type = { | |
1288 | .owner = THIS_MODULE, | |
ef94b186 | 1289 | .name = "overlay", |
e9be9d5e MS |
1290 | .mount = ovl_mount, |
1291 | .kill_sb = kill_anon_super, | |
1292 | }; | |
ef94b186 | 1293 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1294 | |
13cf199d AG |
1295 | static void ovl_inode_init_once(void *foo) |
1296 | { | |
1297 | struct ovl_inode *oi = foo; | |
1298 | ||
1299 | inode_init_once(&oi->vfs_inode); | |
1300 | } | |
1301 | ||
e9be9d5e MS |
1302 | static int __init ovl_init(void) |
1303 | { | |
13cf199d AG |
1304 | int err; |
1305 | ||
1306 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1307 | sizeof(struct ovl_inode), 0, | |
1308 | (SLAB_RECLAIM_ACCOUNT| | |
1309 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
1310 | ovl_inode_init_once); | |
1311 | if (ovl_inode_cachep == NULL) | |
1312 | return -ENOMEM; | |
1313 | ||
1314 | err = register_filesystem(&ovl_fs_type); | |
1315 | if (err) | |
1316 | kmem_cache_destroy(ovl_inode_cachep); | |
1317 | ||
1318 | return err; | |
e9be9d5e MS |
1319 | } |
1320 | ||
1321 | static void __exit ovl_exit(void) | |
1322 | { | |
1323 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1324 | |
1325 | /* | |
1326 | * Make sure all delayed rcu free inodes are flushed before we | |
1327 | * destroy cache. | |
1328 | */ | |
1329 | rcu_barrier(); | |
1330 | kmem_cache_destroy(ovl_inode_cachep); | |
1331 | ||
e9be9d5e MS |
1332 | } |
1333 | ||
1334 | module_init(ovl_init); | |
1335 | module_exit(ovl_exit); |