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> |
e487d889 | 20 | #include <linux/exportfs.h> |
e9be9d5e MS |
21 | #include "overlayfs.h" |
22 | ||
23 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
24 | MODULE_DESCRIPTION("Overlay filesystem"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
e9be9d5e MS |
27 | |
28 | struct ovl_dir_cache; | |
29 | ||
a78d9f0d MS |
30 | #define OVL_MAX_STACK 500 |
31 | ||
688ea0e5 MS |
32 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
33 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); | |
34 | MODULE_PARM_DESC(ovl_redirect_dir_def, | |
35 | "Default to on or off for the redirect_dir feature"); | |
e9be9d5e | 36 | |
438c84c2 MS |
37 | static bool ovl_redirect_always_follow = |
38 | IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); | |
39 | module_param_named(redirect_always_follow, ovl_redirect_always_follow, | |
40 | bool, 0644); | |
41 | MODULE_PARM_DESC(ovl_redirect_always_follow, | |
42 | "Follow redirects even if redirect_dir feature is turned off"); | |
43 | ||
02bcd157 AG |
44 | static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); |
45 | module_param_named(index, ovl_index_def, bool, 0644); | |
46 | MODULE_PARM_DESC(ovl_index_def, | |
47 | "Default to on or off for the inodes index feature"); | |
48 | ||
f168f109 AG |
49 | static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); |
50 | module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); | |
51 | MODULE_PARM_DESC(ovl_nfs_export_def, | |
52 | "Default to on or off for the NFS export feature"); | |
53 | ||
795939a9 AG |
54 | static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); |
55 | module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); | |
56 | MODULE_PARM_DESC(ovl_xino_auto_def, | |
57 | "Auto enable xino feature"); | |
58 | ||
4155c10a MS |
59 | static void ovl_entry_stack_free(struct ovl_entry *oe) |
60 | { | |
61 | unsigned int i; | |
62 | ||
63 | for (i = 0; i < oe->numlower; i++) | |
64 | dput(oe->lowerstack[i].dentry); | |
65 | } | |
66 | ||
e9be9d5e MS |
67 | static void ovl_dentry_release(struct dentry *dentry) |
68 | { | |
69 | struct ovl_entry *oe = dentry->d_fsdata; | |
70 | ||
71 | if (oe) { | |
4155c10a | 72 | ovl_entry_stack_free(oe); |
e9be9d5e MS |
73 | kfree_rcu(oe, rcu); |
74 | } | |
75 | } | |
76 | ||
b0990fbb AG |
77 | static int ovl_check_append_only(struct inode *inode, int flag) |
78 | { | |
79 | /* | |
80 | * This test was moot in vfs may_open() because overlay inode does | |
81 | * not have the S_APPEND flag, so re-check on real upper inode | |
82 | */ | |
83 | if (IS_APPEND(inode)) { | |
84 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) | |
85 | return -EPERM; | |
86 | if (flag & O_TRUNC) | |
87 | return -EPERM; | |
88 | } | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
2d902671 MS |
93 | static struct dentry *ovl_d_real(struct dentry *dentry, |
94 | const struct inode *inode, | |
4ab30319 | 95 | unsigned int open_flags) |
d101a125 MS |
96 | { |
97 | struct dentry *real; | |
b0990fbb | 98 | int err; |
d101a125 | 99 | |
e8c985ba MS |
100 | /* It's an overlay file */ |
101 | if (inode && d_inode(dentry) == inode) | |
102 | return dentry; | |
103 | ||
ca4c8a3a | 104 | if (!d_is_reg(dentry)) { |
d101a125 MS |
105 | if (!inode || inode == d_inode(dentry)) |
106 | return dentry; | |
107 | goto bug; | |
108 | } | |
109 | ||
2d902671 | 110 | if (open_flags) { |
b0990fbb | 111 | err = ovl_open_maybe_copy_up(dentry, open_flags); |
2d902671 MS |
112 | if (err) |
113 | return ERR_PTR(err); | |
114 | } | |
115 | ||
d101a125 | 116 | real = ovl_dentry_upper(dentry); |
b0990fbb AG |
117 | if (real && (!inode || inode == d_inode(real))) { |
118 | if (!inode) { | |
119 | err = ovl_check_append_only(d_inode(real), open_flags); | |
120 | if (err) | |
121 | return ERR_PTR(err); | |
122 | } | |
d101a125 | 123 | return real; |
b0990fbb | 124 | } |
d101a125 MS |
125 | |
126 | real = ovl_dentry_lower(dentry); | |
127 | if (!real) | |
128 | goto bug; | |
129 | ||
c4fcfc16 | 130 | /* Handle recursion */ |
4ab30319 | 131 | real = d_real(real, inode, open_flags); |
c4fcfc16 | 132 | |
d101a125 MS |
133 | if (!inode || inode == d_inode(real)) |
134 | return real; | |
d101a125 | 135 | bug: |
656189d2 | 136 | WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, |
d101a125 MS |
137 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); |
138 | return dentry; | |
139 | } | |
140 | ||
7c03b5d4 MS |
141 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
142 | { | |
143 | struct ovl_entry *oe = dentry->d_fsdata; | |
144 | unsigned int i; | |
145 | int ret = 1; | |
146 | ||
147 | for (i = 0; i < oe->numlower; i++) { | |
148 | struct dentry *d = oe->lowerstack[i].dentry; | |
149 | ||
150 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
151 | ret = d->d_op->d_revalidate(d, flags); | |
152 | if (ret < 0) | |
153 | return ret; | |
154 | if (!ret) { | |
155 | if (!(flags & LOOKUP_RCU)) | |
156 | d_invalidate(d); | |
157 | return -ESTALE; | |
158 | } | |
159 | } | |
160 | } | |
161 | return 1; | |
162 | } | |
163 | ||
164 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
165 | { | |
166 | struct ovl_entry *oe = dentry->d_fsdata; | |
167 | unsigned int i; | |
168 | int ret = 1; | |
169 | ||
170 | for (i = 0; i < oe->numlower; i++) { | |
171 | struct dentry *d = oe->lowerstack[i].dentry; | |
172 | ||
173 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
174 | ret = d->d_op->d_weak_revalidate(d, flags); | |
175 | if (ret <= 0) | |
176 | break; | |
177 | } | |
178 | } | |
179 | return ret; | |
180 | } | |
181 | ||
e9be9d5e MS |
182 | static const struct dentry_operations ovl_dentry_operations = { |
183 | .d_release = ovl_dentry_release, | |
d101a125 | 184 | .d_real = ovl_d_real, |
e9be9d5e MS |
185 | }; |
186 | ||
7c03b5d4 MS |
187 | static const struct dentry_operations ovl_reval_dentry_operations = { |
188 | .d_release = ovl_dentry_release, | |
d101a125 | 189 | .d_real = ovl_d_real, |
7c03b5d4 MS |
190 | .d_revalidate = ovl_dentry_revalidate, |
191 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
192 | }; | |
193 | ||
13cf199d AG |
194 | static struct kmem_cache *ovl_inode_cachep; |
195 | ||
196 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
197 | { | |
198 | struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); | |
199 | ||
b3885bd6 HN |
200 | if (!oi) |
201 | return NULL; | |
202 | ||
04a01ac7 | 203 | oi->cache = NULL; |
cf31c463 | 204 | oi->redirect = NULL; |
04a01ac7 | 205 | oi->version = 0; |
13c72075 | 206 | oi->flags = 0; |
09d8b586 | 207 | oi->__upperdentry = NULL; |
25b7713a | 208 | oi->lower = NULL; |
a015dafc | 209 | mutex_init(&oi->lock); |
25b7713a | 210 | |
13cf199d AG |
211 | return &oi->vfs_inode; |
212 | } | |
213 | ||
214 | static void ovl_i_callback(struct rcu_head *head) | |
215 | { | |
216 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
217 | ||
218 | kmem_cache_free(ovl_inode_cachep, OVL_I(inode)); | |
219 | } | |
220 | ||
221 | static void ovl_destroy_inode(struct inode *inode) | |
222 | { | |
09d8b586 MS |
223 | struct ovl_inode *oi = OVL_I(inode); |
224 | ||
225 | dput(oi->__upperdentry); | |
31747eda | 226 | iput(oi->lower); |
cf31c463 | 227 | kfree(oi->redirect); |
4edb83bb | 228 | ovl_dir_cache_free(inode); |
a015dafc | 229 | mutex_destroy(&oi->lock); |
09d8b586 | 230 | |
13cf199d AG |
231 | call_rcu(&inode->i_rcu, ovl_i_callback); |
232 | } | |
233 | ||
ad204488 | 234 | static void ovl_free_fs(struct ovl_fs *ofs) |
e9be9d5e | 235 | { |
dd662667 | 236 | unsigned i; |
e9be9d5e | 237 | |
ad204488 MS |
238 | dput(ofs->indexdir); |
239 | dput(ofs->workdir); | |
240 | if (ofs->workdir_locked) | |
241 | ovl_inuse_unlock(ofs->workbasedir); | |
242 | dput(ofs->workbasedir); | |
243 | if (ofs->upperdir_locked) | |
244 | ovl_inuse_unlock(ofs->upper_mnt->mnt_root); | |
245 | mntput(ofs->upper_mnt); | |
5148626b | 246 | for (i = 0; i < ofs->numlower; i++) |
ad204488 | 247 | mntput(ofs->lower_layers[i].mnt); |
5148626b AG |
248 | for (i = 0; i < ofs->numlowerfs; i++) |
249 | free_anon_bdev(ofs->lower_fs[i].pseudo_dev); | |
ad204488 | 250 | kfree(ofs->lower_layers); |
5148626b | 251 | kfree(ofs->lower_fs); |
ad204488 MS |
252 | |
253 | kfree(ofs->config.lowerdir); | |
254 | kfree(ofs->config.upperdir); | |
255 | kfree(ofs->config.workdir); | |
438c84c2 | 256 | kfree(ofs->config.redirect_mode); |
ad204488 MS |
257 | if (ofs->creator_cred) |
258 | put_cred(ofs->creator_cred); | |
259 | kfree(ofs); | |
e9be9d5e MS |
260 | } |
261 | ||
a9075cdb MS |
262 | static void ovl_put_super(struct super_block *sb) |
263 | { | |
264 | struct ovl_fs *ofs = sb->s_fs_info; | |
265 | ||
266 | ovl_free_fs(ofs); | |
267 | } | |
268 | ||
e8d4bfe3 | 269 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
270 | static int ovl_sync_fs(struct super_block *sb, int wait) |
271 | { | |
ad204488 | 272 | struct ovl_fs *ofs = sb->s_fs_info; |
e593b2bf AG |
273 | struct super_block *upper_sb; |
274 | int ret; | |
275 | ||
ad204488 | 276 | if (!ofs->upper_mnt) |
e593b2bf | 277 | return 0; |
e8d4bfe3 CX |
278 | |
279 | /* | |
280 | * If this is a sync(2) call or an emergency sync, all the super blocks | |
281 | * will be iterated, including upper_sb, so no need to do anything. | |
282 | * | |
283 | * If this is a syncfs(2) call, then we do need to call | |
284 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
285 | * called with wait == 1. | |
286 | */ | |
287 | if (!wait) | |
e593b2bf AG |
288 | return 0; |
289 | ||
e8d4bfe3 CX |
290 | upper_sb = ofs->upper_mnt->mnt_sb; |
291 | ||
e593b2bf | 292 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 293 | ret = sync_filesystem(upper_sb); |
e593b2bf | 294 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 295 | |
e593b2bf AG |
296 | return ret; |
297 | } | |
298 | ||
cc259639 AW |
299 | /** |
300 | * ovl_statfs | |
301 | * @sb: The overlayfs super block | |
302 | * @buf: The struct kstatfs to fill in with stats | |
303 | * | |
304 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 305 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
306 | */ |
307 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
308 | { | |
309 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
310 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
311 | struct path path; | |
312 | int err; | |
313 | ||
4ebc5818 | 314 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
315 | |
316 | err = vfs_statfs(&path, buf); | |
317 | if (!err) { | |
6b2d5fe4 | 318 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
319 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
320 | } | |
321 | ||
322 | return err; | |
323 | } | |
324 | ||
02bcd157 | 325 | /* Will this overlay be forced to mount/remount ro? */ |
ad204488 | 326 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
02bcd157 | 327 | { |
ad204488 | 328 | return (!ofs->upper_mnt || !ofs->workdir); |
02bcd157 AG |
329 | } |
330 | ||
438c84c2 MS |
331 | static const char *ovl_redirect_mode_def(void) |
332 | { | |
333 | return ovl_redirect_dir_def ? "on" : "off"; | |
334 | } | |
335 | ||
795939a9 AG |
336 | enum { |
337 | OVL_XINO_OFF, | |
338 | OVL_XINO_AUTO, | |
339 | OVL_XINO_ON, | |
340 | }; | |
341 | ||
342 | static const char * const ovl_xino_str[] = { | |
343 | "off", | |
344 | "auto", | |
345 | "on", | |
346 | }; | |
347 | ||
348 | static inline int ovl_xino_def(void) | |
349 | { | |
350 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; | |
351 | } | |
352 | ||
f45827e8 EZ |
353 | /** |
354 | * ovl_show_options | |
355 | * | |
356 | * Prints the mount options for a given superblock. | |
357 | * Returns zero; does not fail. | |
358 | */ | |
359 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
360 | { | |
361 | struct super_block *sb = dentry->d_sb; | |
ad204488 | 362 | struct ovl_fs *ofs = sb->s_fs_info; |
f45827e8 | 363 | |
ad204488 MS |
364 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
365 | if (ofs->config.upperdir) { | |
366 | seq_show_option(m, "upperdir", ofs->config.upperdir); | |
367 | seq_show_option(m, "workdir", ofs->config.workdir); | |
53a08cb9 | 368 | } |
ad204488 | 369 | if (ofs->config.default_permissions) |
8d3095f4 | 370 | seq_puts(m, ",default_permissions"); |
438c84c2 MS |
371 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
372 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); | |
ad204488 | 373 | if (ofs->config.index != ovl_index_def) |
438c84c2 | 374 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
f168f109 AG |
375 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
376 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? | |
377 | "on" : "off"); | |
795939a9 AG |
378 | if (ofs->config.xino != ovl_xino_def()) |
379 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); | |
f45827e8 EZ |
380 | return 0; |
381 | } | |
382 | ||
3cdf6fe9 SL |
383 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
384 | { | |
ad204488 | 385 | struct ovl_fs *ofs = sb->s_fs_info; |
3cdf6fe9 | 386 | |
1751e8a6 | 387 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
3cdf6fe9 SL |
388 | return -EROFS; |
389 | ||
390 | return 0; | |
391 | } | |
392 | ||
e9be9d5e | 393 | static const struct super_operations ovl_super_operations = { |
13cf199d AG |
394 | .alloc_inode = ovl_alloc_inode, |
395 | .destroy_inode = ovl_destroy_inode, | |
396 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 397 | .put_super = ovl_put_super, |
e593b2bf | 398 | .sync_fs = ovl_sync_fs, |
cc259639 | 399 | .statfs = ovl_statfs, |
f45827e8 | 400 | .show_options = ovl_show_options, |
3cdf6fe9 | 401 | .remount_fs = ovl_remount, |
e9be9d5e MS |
402 | }; |
403 | ||
404 | enum { | |
405 | OPT_LOWERDIR, | |
406 | OPT_UPPERDIR, | |
407 | OPT_WORKDIR, | |
8d3095f4 | 408 | OPT_DEFAULT_PERMISSIONS, |
438c84c2 | 409 | OPT_REDIRECT_DIR, |
02bcd157 AG |
410 | OPT_INDEX_ON, |
411 | OPT_INDEX_OFF, | |
f168f109 AG |
412 | OPT_NFS_EXPORT_ON, |
413 | OPT_NFS_EXPORT_OFF, | |
795939a9 AG |
414 | OPT_XINO_ON, |
415 | OPT_XINO_OFF, | |
416 | OPT_XINO_AUTO, | |
e9be9d5e MS |
417 | OPT_ERR, |
418 | }; | |
419 | ||
420 | static const match_table_t ovl_tokens = { | |
421 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
422 | {OPT_UPPERDIR, "upperdir=%s"}, | |
423 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 424 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
438c84c2 | 425 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
02bcd157 AG |
426 | {OPT_INDEX_ON, "index=on"}, |
427 | {OPT_INDEX_OFF, "index=off"}, | |
f168f109 AG |
428 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
429 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, | |
795939a9 AG |
430 | {OPT_XINO_ON, "xino=on"}, |
431 | {OPT_XINO_OFF, "xino=off"}, | |
432 | {OPT_XINO_AUTO, "xino=auto"}, | |
e9be9d5e MS |
433 | {OPT_ERR, NULL} |
434 | }; | |
435 | ||
91c77947 MS |
436 | static char *ovl_next_opt(char **s) |
437 | { | |
438 | char *sbegin = *s; | |
439 | char *p; | |
440 | ||
441 | if (sbegin == NULL) | |
442 | return NULL; | |
443 | ||
444 | for (p = sbegin; *p; p++) { | |
445 | if (*p == '\\') { | |
446 | p++; | |
447 | if (!*p) | |
448 | break; | |
449 | } else if (*p == ',') { | |
450 | *p = '\0'; | |
451 | *s = p + 1; | |
452 | return sbegin; | |
453 | } | |
454 | } | |
455 | *s = NULL; | |
456 | return sbegin; | |
457 | } | |
458 | ||
438c84c2 MS |
459 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
460 | { | |
461 | if (strcmp(mode, "on") == 0) { | |
462 | config->redirect_dir = true; | |
463 | /* | |
464 | * Does not make sense to have redirect creation without | |
465 | * redirect following. | |
466 | */ | |
467 | config->redirect_follow = true; | |
468 | } else if (strcmp(mode, "follow") == 0) { | |
469 | config->redirect_follow = true; | |
470 | } else if (strcmp(mode, "off") == 0) { | |
471 | if (ovl_redirect_always_follow) | |
472 | config->redirect_follow = true; | |
473 | } else if (strcmp(mode, "nofollow") != 0) { | |
474 | pr_err("overlayfs: bad mount option \"redirect_dir=%s\"\n", | |
475 | mode); | |
476 | return -EINVAL; | |
477 | } | |
478 | ||
479 | return 0; | |
480 | } | |
481 | ||
e9be9d5e MS |
482 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
483 | { | |
484 | char *p; | |
485 | ||
438c84c2 MS |
486 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
487 | if (!config->redirect_mode) | |
488 | return -ENOMEM; | |
489 | ||
91c77947 | 490 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
491 | int token; |
492 | substring_t args[MAX_OPT_ARGS]; | |
493 | ||
494 | if (!*p) | |
495 | continue; | |
496 | ||
497 | token = match_token(p, ovl_tokens, args); | |
498 | switch (token) { | |
499 | case OPT_UPPERDIR: | |
500 | kfree(config->upperdir); | |
501 | config->upperdir = match_strdup(&args[0]); | |
502 | if (!config->upperdir) | |
503 | return -ENOMEM; | |
504 | break; | |
505 | ||
506 | case OPT_LOWERDIR: | |
507 | kfree(config->lowerdir); | |
508 | config->lowerdir = match_strdup(&args[0]); | |
509 | if (!config->lowerdir) | |
510 | return -ENOMEM; | |
511 | break; | |
512 | ||
513 | case OPT_WORKDIR: | |
514 | kfree(config->workdir); | |
515 | config->workdir = match_strdup(&args[0]); | |
516 | if (!config->workdir) | |
517 | return -ENOMEM; | |
518 | break; | |
519 | ||
8d3095f4 MS |
520 | case OPT_DEFAULT_PERMISSIONS: |
521 | config->default_permissions = true; | |
522 | break; | |
523 | ||
438c84c2 MS |
524 | case OPT_REDIRECT_DIR: |
525 | kfree(config->redirect_mode); | |
526 | config->redirect_mode = match_strdup(&args[0]); | |
527 | if (!config->redirect_mode) | |
528 | return -ENOMEM; | |
a6c60655 MS |
529 | break; |
530 | ||
02bcd157 AG |
531 | case OPT_INDEX_ON: |
532 | config->index = true; | |
533 | break; | |
534 | ||
535 | case OPT_INDEX_OFF: | |
536 | config->index = false; | |
537 | break; | |
538 | ||
f168f109 AG |
539 | case OPT_NFS_EXPORT_ON: |
540 | config->nfs_export = true; | |
541 | break; | |
542 | ||
543 | case OPT_NFS_EXPORT_OFF: | |
544 | config->nfs_export = false; | |
545 | break; | |
546 | ||
795939a9 AG |
547 | case OPT_XINO_ON: |
548 | config->xino = OVL_XINO_ON; | |
549 | break; | |
550 | ||
551 | case OPT_XINO_OFF: | |
552 | config->xino = OVL_XINO_OFF; | |
553 | break; | |
554 | ||
555 | case OPT_XINO_AUTO: | |
556 | config->xino = OVL_XINO_AUTO; | |
557 | break; | |
558 | ||
e9be9d5e | 559 | default: |
bead55ef | 560 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
561 | return -EINVAL; |
562 | } | |
563 | } | |
71cbad7e | 564 | |
565 | /* Workdir is useless in non-upper mount */ | |
566 | if (!config->upperdir && config->workdir) { | |
567 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
568 | config->workdir); | |
569 | kfree(config->workdir); | |
570 | config->workdir = NULL; | |
571 | } | |
572 | ||
438c84c2 | 573 | return ovl_parse_redirect_mode(config, config->redirect_mode); |
e9be9d5e MS |
574 | } |
575 | ||
576 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 577 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 578 | |
ad204488 | 579 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 580 | const char *name, bool persist) |
e9be9d5e | 581 | { |
ad204488 MS |
582 | struct inode *dir = ofs->workbasedir->d_inode; |
583 | struct vfsmount *mnt = ofs->upper_mnt; | |
e9be9d5e MS |
584 | struct dentry *work; |
585 | int err; | |
586 | bool retried = false; | |
6b8aa129 | 587 | bool locked = false; |
e9be9d5e | 588 | |
5955102c | 589 | inode_lock_nested(dir, I_MUTEX_PARENT); |
6b8aa129 AG |
590 | locked = true; |
591 | ||
e9be9d5e | 592 | retry: |
ad204488 | 593 | work = lookup_one_len(name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
594 | |
595 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
596 | struct iattr attr = { |
597 | .ia_valid = ATTR_MODE, | |
32a3d848 | 598 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 599 | }; |
e9be9d5e MS |
600 | |
601 | if (work->d_inode) { | |
602 | err = -EEXIST; | |
603 | if (retried) | |
604 | goto out_dput; | |
605 | ||
6b8aa129 AG |
606 | if (persist) |
607 | goto out_unlock; | |
608 | ||
e9be9d5e | 609 | retried = true; |
eea2fb48 | 610 | ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e MS |
611 | dput(work); |
612 | goto retry; | |
613 | } | |
614 | ||
95a1c815 MS |
615 | work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); |
616 | err = PTR_ERR(work); | |
617 | if (IS_ERR(work)) | |
618 | goto out_err; | |
c11b9fdd | 619 | |
cb348edb MS |
620 | /* |
621 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
622 | * | |
623 | * a) success (there was a POSIX ACL xattr and was removed) | |
624 | * b) -ENODATA (there was no POSIX ACL xattr) | |
625 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
626 | * | |
627 | * There are various other error values that could effectively | |
628 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
629 | * if the xattr name is too long), but the set of filesystems | |
630 | * allowed as upper are limited to "normal" ones, where checking | |
631 | * for the above two errors is sufficient. | |
632 | */ | |
c11b9fdd | 633 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 634 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
635 | goto out_dput; |
636 | ||
637 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 638 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
639 | goto out_dput; |
640 | ||
641 | /* Clear any inherited mode bits */ | |
642 | inode_lock(work->d_inode); | |
643 | err = notify_change(work, &attr, NULL); | |
644 | inode_unlock(work->d_inode); | |
645 | if (err) | |
646 | goto out_dput; | |
6b8aa129 AG |
647 | } else { |
648 | err = PTR_ERR(work); | |
649 | goto out_err; | |
e9be9d5e MS |
650 | } |
651 | out_unlock: | |
6b8aa129 AG |
652 | if (locked) |
653 | inode_unlock(dir); | |
e9be9d5e MS |
654 | |
655 | return work; | |
656 | ||
657 | out_dput: | |
658 | dput(work); | |
6b8aa129 AG |
659 | out_err: |
660 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", | |
ad204488 | 661 | ofs->config.workdir, name, -err); |
6b8aa129 | 662 | work = NULL; |
e9be9d5e MS |
663 | goto out_unlock; |
664 | } | |
665 | ||
91c77947 MS |
666 | static void ovl_unescape(char *s) |
667 | { | |
668 | char *d = s; | |
669 | ||
670 | for (;; s++, d++) { | |
671 | if (*s == '\\') | |
672 | s++; | |
673 | *d = *s; | |
674 | if (!*s) | |
675 | break; | |
676 | } | |
677 | } | |
678 | ||
ab508822 MS |
679 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
680 | { | |
a78d9f0d | 681 | int err = -EINVAL; |
ab508822 | 682 | |
a78d9f0d MS |
683 | if (!*name) { |
684 | pr_err("overlayfs: empty lowerdir\n"); | |
685 | goto out; | |
686 | } | |
ab508822 MS |
687 | err = kern_path(name, LOOKUP_FOLLOW, path); |
688 | if (err) { | |
689 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
690 | goto out; | |
691 | } | |
692 | err = -EINVAL; | |
7c03b5d4 | 693 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
694 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
695 | goto out_put; | |
696 | } | |
2b8c30e9 | 697 | if (!d_is_dir(path->dentry)) { |
ab508822 MS |
698 | pr_err("overlayfs: '%s' not a directory\n", name); |
699 | goto out_put; | |
700 | } | |
701 | return 0; | |
702 | ||
703 | out_put: | |
8aafcb59 | 704 | path_put_init(path); |
ab508822 MS |
705 | out: |
706 | return err; | |
707 | } | |
708 | ||
709 | static int ovl_mount_dir(const char *name, struct path *path) | |
710 | { | |
711 | int err = -ENOMEM; | |
712 | char *tmp = kstrdup(name, GFP_KERNEL); | |
713 | ||
714 | if (tmp) { | |
715 | ovl_unescape(tmp); | |
716 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
717 | |
718 | if (!err) | |
719 | if (ovl_dentry_remote(path->dentry)) { | |
720 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
721 | tmp); | |
8aafcb59 | 722 | path_put_init(path); |
7c03b5d4 MS |
723 | err = -EINVAL; |
724 | } | |
ab508822 MS |
725 | kfree(tmp); |
726 | } | |
727 | return err; | |
728 | } | |
729 | ||
6b2d5fe4 MS |
730 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
731 | const char *name) | |
ab508822 | 732 | { |
ab508822 | 733 | struct kstatfs statfs; |
6b2d5fe4 MS |
734 | int err = vfs_statfs(path, &statfs); |
735 | ||
736 | if (err) | |
737 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
738 | else | |
739 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
740 | ||
741 | return err; | |
742 | } | |
743 | ||
744 | static int ovl_lower_dir(const char *name, struct path *path, | |
745 | struct ovl_fs *ofs, int *stack_depth, bool *remote) | |
746 | { | |
e487d889 | 747 | int fh_type; |
6b2d5fe4 | 748 | int err; |
ab508822 | 749 | |
a78d9f0d | 750 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
751 | if (err) |
752 | goto out; | |
753 | ||
6b2d5fe4 MS |
754 | err = ovl_check_namelen(path, ofs, name); |
755 | if (err) | |
ab508822 | 756 | goto out_put; |
6b2d5fe4 | 757 | |
ab508822 MS |
758 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
759 | ||
7c03b5d4 MS |
760 | if (ovl_dentry_remote(path->dentry)) |
761 | *remote = true; | |
762 | ||
02bcd157 | 763 | /* |
f168f109 AG |
764 | * The inodes index feature and NFS export need to encode and decode |
765 | * file handles, so they require that all layers support them. | |
02bcd157 | 766 | */ |
e487d889 | 767 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 768 | if ((ofs->config.nfs_export || |
e487d889 | 769 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 770 | ofs->config.index = false; |
f168f109 AG |
771 | ofs->config.nfs_export = false; |
772 | pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", | |
773 | name); | |
02bcd157 AG |
774 | } |
775 | ||
e487d889 AG |
776 | /* Check if lower fs has 32bit inode numbers */ |
777 | if (fh_type != FILEID_INO32_GEN) | |
778 | ofs->xino_bits = 0; | |
779 | ||
ab508822 MS |
780 | return 0; |
781 | ||
782 | out_put: | |
8aafcb59 | 783 | path_put_init(path); |
ab508822 MS |
784 | out: |
785 | return err; | |
786 | } | |
787 | ||
e9be9d5e MS |
788 | /* Workdir should not be subdir of upperdir and vice versa */ |
789 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
790 | { | |
791 | bool ok = false; | |
792 | ||
793 | if (workdir != upperdir) { | |
794 | ok = (lock_rename(workdir, upperdir) == NULL); | |
795 | unlock_rename(workdir, upperdir); | |
796 | } | |
797 | return ok; | |
798 | } | |
799 | ||
a78d9f0d MS |
800 | static unsigned int ovl_split_lowerdirs(char *str) |
801 | { | |
802 | unsigned int ctr = 1; | |
803 | char *s, *d; | |
804 | ||
805 | for (s = d = str;; s++, d++) { | |
806 | if (*s == '\\') { | |
807 | s++; | |
808 | } else if (*s == ':') { | |
809 | *d = '\0'; | |
810 | ctr++; | |
811 | continue; | |
812 | } | |
813 | *d = *s; | |
814 | if (!*s) | |
815 | break; | |
816 | } | |
817 | return ctr; | |
818 | } | |
819 | ||
0eb45fc3 AG |
820 | static int __maybe_unused |
821 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
822 | struct dentry *dentry, struct inode *inode, | |
823 | const char *name, void *buffer, size_t size) | |
824 | { | |
1d88f183 | 825 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
0eb45fc3 AG |
826 | } |
827 | ||
0c97be22 AG |
828 | static int __maybe_unused |
829 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
830 | struct dentry *dentry, struct inode *inode, | |
831 | const char *name, const void *value, | |
832 | size_t size, int flags) | |
d837a49b MS |
833 | { |
834 | struct dentry *workdir = ovl_workdir(dentry); | |
09d8b586 | 835 | struct inode *realinode = ovl_inode_real(inode); |
d837a49b MS |
836 | struct posix_acl *acl = NULL; |
837 | int err; | |
838 | ||
839 | /* Check that everything is OK before copy-up */ | |
840 | if (value) { | |
841 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
842 | if (IS_ERR(acl)) | |
843 | return PTR_ERR(acl); | |
844 | } | |
845 | err = -EOPNOTSUPP; | |
846 | if (!IS_POSIXACL(d_inode(workdir))) | |
847 | goto out_acl_release; | |
848 | if (!realinode->i_op->set_acl) | |
849 | goto out_acl_release; | |
850 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
851 | err = acl ? -EACCES : 0; | |
852 | goto out_acl_release; | |
853 | } | |
854 | err = -EPERM; | |
855 | if (!inode_owner_or_capable(inode)) | |
856 | goto out_acl_release; | |
857 | ||
858 | posix_acl_release(acl); | |
859 | ||
fd3220d3 MS |
860 | /* |
861 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
862 | * be done with mounter's capabilities and so that won't do it for us). | |
863 | */ | |
864 | if (unlikely(inode->i_mode & S_ISGID) && | |
865 | handler->flags == ACL_TYPE_ACCESS && | |
866 | !in_group_p(inode->i_gid) && | |
867 | !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { | |
868 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; | |
869 | ||
870 | err = ovl_setattr(dentry, &iattr); | |
871 | if (err) | |
872 | return err; | |
873 | } | |
874 | ||
1d88f183 | 875 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
ce31513a | 876 | if (!err) |
09d8b586 | 877 | ovl_copyattr(ovl_inode_real(inode), inode); |
ce31513a MS |
878 | |
879 | return err; | |
d837a49b MS |
880 | |
881 | out_acl_release: | |
882 | posix_acl_release(acl); | |
883 | return err; | |
884 | } | |
885 | ||
0eb45fc3 AG |
886 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
887 | struct dentry *dentry, struct inode *inode, | |
888 | const char *name, void *buffer, size_t size) | |
889 | { | |
48fab5d7 | 890 | return -EOPNOTSUPP; |
0eb45fc3 AG |
891 | } |
892 | ||
d837a49b MS |
893 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
894 | struct dentry *dentry, struct inode *inode, | |
895 | const char *name, const void *value, | |
896 | size_t size, int flags) | |
897 | { | |
48fab5d7 | 898 | return -EOPNOTSUPP; |
d837a49b MS |
899 | } |
900 | ||
0eb45fc3 AG |
901 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
902 | struct dentry *dentry, struct inode *inode, | |
903 | const char *name, void *buffer, size_t size) | |
904 | { | |
1d88f183 | 905 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
906 | } |
907 | ||
0e585ccc AG |
908 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
909 | struct dentry *dentry, struct inode *inode, | |
910 | const char *name, const void *value, | |
911 | size_t size, int flags) | |
912 | { | |
1d88f183 | 913 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
914 | } |
915 | ||
0c97be22 AG |
916 | static const struct xattr_handler __maybe_unused |
917 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
918 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
919 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 920 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
921 | .set = ovl_posix_acl_xattr_set, |
922 | }; | |
923 | ||
0c97be22 AG |
924 | static const struct xattr_handler __maybe_unused |
925 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
926 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
927 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 928 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
929 | .set = ovl_posix_acl_xattr_set, |
930 | }; | |
931 | ||
932 | static const struct xattr_handler ovl_own_xattr_handler = { | |
933 | .prefix = OVL_XATTR_PREFIX, | |
0eb45fc3 | 934 | .get = ovl_own_xattr_get, |
d837a49b MS |
935 | .set = ovl_own_xattr_set, |
936 | }; | |
937 | ||
938 | static const struct xattr_handler ovl_other_xattr_handler = { | |
939 | .prefix = "", /* catch all */ | |
0eb45fc3 | 940 | .get = ovl_other_xattr_get, |
d837a49b MS |
941 | .set = ovl_other_xattr_set, |
942 | }; | |
943 | ||
944 | static const struct xattr_handler *ovl_xattr_handlers[] = { | |
0c97be22 | 945 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
946 | &ovl_posix_acl_access_xattr_handler, |
947 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 948 | #endif |
d837a49b MS |
949 | &ovl_own_xattr_handler, |
950 | &ovl_other_xattr_handler, | |
951 | NULL | |
952 | }; | |
953 | ||
ad204488 | 954 | static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath) |
6ee8acf0 | 955 | { |
5064975e | 956 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
957 | int err; |
958 | ||
ad204488 | 959 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
6ee8acf0 MS |
960 | if (err) |
961 | goto out; | |
962 | ||
963 | /* Upper fs should not be r/o */ | |
964 | if (sb_rdonly(upperpath->mnt->mnt_sb)) { | |
965 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
966 | err = -EINVAL; | |
967 | goto out; | |
968 | } | |
969 | ||
ad204488 | 970 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
971 | if (err) |
972 | goto out; | |
973 | ||
974 | err = -EBUSY; | |
975 | if (ovl_inuse_trylock(upperpath->dentry)) { | |
ad204488 MS |
976 | ofs->upperdir_locked = true; |
977 | } else if (ofs->config.index) { | |
6ee8acf0 MS |
978 | pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n"); |
979 | goto out; | |
980 | } else { | |
981 | pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
982 | } | |
5064975e MS |
983 | |
984 | upper_mnt = clone_private_mount(upperpath); | |
985 | err = PTR_ERR(upper_mnt); | |
986 | if (IS_ERR(upper_mnt)) { | |
987 | pr_err("overlayfs: failed to clone upperpath\n"); | |
988 | goto out; | |
989 | } | |
990 | ||
991 | /* Don't inherit atime flags */ | |
992 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
ad204488 | 993 | ofs->upper_mnt = upper_mnt; |
6ee8acf0 MS |
994 | err = 0; |
995 | out: | |
996 | return err; | |
997 | } | |
998 | ||
ad204488 | 999 | static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) |
8ed61dc3 | 1000 | { |
2ba9d57e | 1001 | struct vfsmount *mnt = ofs->upper_mnt; |
8ed61dc3 | 1002 | struct dentry *temp; |
e487d889 | 1003 | int fh_type; |
8ed61dc3 MS |
1004 | int err; |
1005 | ||
2ba9d57e AG |
1006 | err = mnt_want_write(mnt); |
1007 | if (err) | |
1008 | return err; | |
1009 | ||
ad204488 MS |
1010 | ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
1011 | if (!ofs->workdir) | |
2ba9d57e | 1012 | goto out; |
8ed61dc3 MS |
1013 | |
1014 | /* | |
1015 | * Upper should support d_type, else whiteouts are visible. Given | |
1016 | * workdir and upper are on same fs, we can do iterate_dir() on | |
1017 | * workdir. This check requires successful creation of workdir in | |
1018 | * previous step. | |
1019 | */ | |
1020 | err = ovl_check_d_type_supported(workpath); | |
1021 | if (err < 0) | |
2ba9d57e | 1022 | goto out; |
8ed61dc3 MS |
1023 | |
1024 | /* | |
1025 | * We allowed this configuration and don't want to break users over | |
1026 | * kernel upgrade. So warn instead of erroring out. | |
1027 | */ | |
1028 | if (!err) | |
1029 | pr_warn("overlayfs: upper fs needs to support d_type.\n"); | |
1030 | ||
1031 | /* Check if upper/work fs supports O_TMPFILE */ | |
ad204488 MS |
1032 | temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); |
1033 | ofs->tmpfile = !IS_ERR(temp); | |
1034 | if (ofs->tmpfile) | |
8ed61dc3 MS |
1035 | dput(temp); |
1036 | else | |
1037 | pr_warn("overlayfs: upper fs does not support tmpfile.\n"); | |
1038 | ||
1039 | /* | |
1040 | * Check if upper/work fs supports trusted.overlay.* xattr | |
1041 | */ | |
ad204488 | 1042 | err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1, 0); |
8ed61dc3 | 1043 | if (err) { |
ad204488 | 1044 | ofs->noxattr = true; |
a683737b AG |
1045 | ofs->config.index = false; |
1046 | pr_warn("overlayfs: upper fs does not support xattr, falling back to index=off.\n"); | |
2ba9d57e | 1047 | err = 0; |
8ed61dc3 | 1048 | } else { |
ad204488 | 1049 | vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
1050 | } |
1051 | ||
1052 | /* Check if upper/work fs supports file handles */ | |
e487d889 AG |
1053 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
1054 | if (ofs->config.index && !fh_type) { | |
ad204488 | 1055 | ofs->config.index = false; |
8ed61dc3 MS |
1056 | pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); |
1057 | } | |
1058 | ||
e487d889 AG |
1059 | /* Check if upper fs has 32bit inode numbers */ |
1060 | if (fh_type != FILEID_INO32_GEN) | |
1061 | ofs->xino_bits = 0; | |
1062 | ||
f168f109 AG |
1063 | /* NFS export of r/w mount depends on index */ |
1064 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1065 | pr_warn("overlayfs: NFS export requires \"index=on\", falling back to nfs_export=off.\n"); | |
1066 | ofs->config.nfs_export = false; | |
1067 | } | |
1068 | ||
2ba9d57e AG |
1069 | out: |
1070 | mnt_drop_write(mnt); | |
1071 | return err; | |
8ed61dc3 MS |
1072 | } |
1073 | ||
ad204488 | 1074 | static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath) |
520d7c86 MS |
1075 | { |
1076 | int err; | |
bca44b52 | 1077 | struct path workpath = { }; |
520d7c86 | 1078 | |
ad204488 | 1079 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
520d7c86 MS |
1080 | if (err) |
1081 | goto out; | |
1082 | ||
1083 | err = -EINVAL; | |
bca44b52 | 1084 | if (upperpath->mnt != workpath.mnt) { |
520d7c86 MS |
1085 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); |
1086 | goto out; | |
1087 | } | |
bca44b52 | 1088 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
520d7c86 MS |
1089 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); |
1090 | goto out; | |
1091 | } | |
1092 | ||
1093 | err = -EBUSY; | |
bca44b52 | 1094 | if (ovl_inuse_trylock(workpath.dentry)) { |
ad204488 MS |
1095 | ofs->workdir_locked = true; |
1096 | } else if (ofs->config.index) { | |
520d7c86 MS |
1097 | pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n"); |
1098 | goto out; | |
1099 | } else { | |
1100 | pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
1101 | } | |
1102 | ||
ad204488 MS |
1103 | ofs->workbasedir = dget(workpath.dentry); |
1104 | err = ovl_make_workdir(ofs, &workpath); | |
bca44b52 MS |
1105 | if (err) |
1106 | goto out; | |
1107 | ||
520d7c86 MS |
1108 | err = 0; |
1109 | out: | |
bca44b52 MS |
1110 | path_put(&workpath); |
1111 | ||
520d7c86 MS |
1112 | return err; |
1113 | } | |
1114 | ||
ad204488 | 1115 | static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe, |
95e6d417 | 1116 | struct path *upperpath) |
f7e3a7d9 | 1117 | { |
2ba9d57e | 1118 | struct vfsmount *mnt = ofs->upper_mnt; |
f7e3a7d9 MS |
1119 | int err; |
1120 | ||
2ba9d57e AG |
1121 | err = mnt_want_write(mnt); |
1122 | if (err) | |
1123 | return err; | |
1124 | ||
f7e3a7d9 | 1125 | /* Verify lower root is upper root origin */ |
d9768076 | 1126 | err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry, |
05122443 | 1127 | true); |
f7e3a7d9 MS |
1128 | if (err) { |
1129 | pr_err("overlayfs: failed to verify upper root origin\n"); | |
1130 | goto out; | |
1131 | } | |
1132 | ||
ad204488 MS |
1133 | ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
1134 | if (ofs->indexdir) { | |
ad1d615c AG |
1135 | /* |
1136 | * Verify upper root is exclusively associated with index dir. | |
1137 | * Older kernels stored upper fh in "trusted.overlay.origin" | |
1138 | * xattr. If that xattr exists, verify that it is a match to | |
1139 | * upper dir file handle. In any case, verify or set xattr | |
1140 | * "trusted.overlay.upper" to indicate that index may have | |
1141 | * directory entries. | |
1142 | */ | |
1143 | if (ovl_check_origin_xattr(ofs->indexdir)) { | |
1144 | err = ovl_verify_set_fh(ofs->indexdir, OVL_XATTR_ORIGIN, | |
1145 | upperpath->dentry, true, false); | |
1146 | if (err) | |
1147 | pr_err("overlayfs: failed to verify index dir 'origin' xattr\n"); | |
1148 | } | |
1149 | err = ovl_verify_upper(ofs->indexdir, upperpath->dentry, true); | |
f7e3a7d9 | 1150 | if (err) |
ad1d615c | 1151 | pr_err("overlayfs: failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
1152 | |
1153 | /* Cleanup bad/stale/orphan index entries */ | |
1154 | if (!err) | |
1eff1a1d | 1155 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 1156 | } |
ad204488 | 1157 | if (err || !ofs->indexdir) |
f7e3a7d9 MS |
1158 | pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
1159 | ||
1160 | out: | |
2ba9d57e | 1161 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
1162 | return err; |
1163 | } | |
1164 | ||
5148626b AG |
1165 | /* Get a unique fsid for the layer */ |
1166 | static int ovl_get_fsid(struct ovl_fs *ofs, struct super_block *sb) | |
1167 | { | |
1168 | unsigned int i; | |
1169 | dev_t dev; | |
1170 | int err; | |
1171 | ||
1172 | /* fsid 0 is reserved for upper fs even with non upper overlay */ | |
1173 | if (ofs->upper_mnt && ofs->upper_mnt->mnt_sb == sb) | |
1174 | return 0; | |
1175 | ||
1176 | for (i = 0; i < ofs->numlowerfs; i++) { | |
1177 | if (ofs->lower_fs[i].sb == sb) | |
1178 | return i + 1; | |
1179 | } | |
1180 | ||
1181 | err = get_anon_bdev(&dev); | |
1182 | if (err) { | |
1183 | pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n"); | |
1184 | return err; | |
1185 | } | |
1186 | ||
1187 | ofs->lower_fs[ofs->numlowerfs].sb = sb; | |
1188 | ofs->lower_fs[ofs->numlowerfs].pseudo_dev = dev; | |
1189 | ofs->numlowerfs++; | |
1190 | ||
1191 | return ofs->numlowerfs; | |
1192 | } | |
1193 | ||
ad204488 | 1194 | static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack, |
520d7c86 MS |
1195 | unsigned int numlower) |
1196 | { | |
1197 | int err; | |
1198 | unsigned int i; | |
1199 | ||
1200 | err = -ENOMEM; | |
ad204488 | 1201 | ofs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer), |
520d7c86 | 1202 | GFP_KERNEL); |
ad204488 | 1203 | if (ofs->lower_layers == NULL) |
520d7c86 | 1204 | goto out; |
5148626b AG |
1205 | |
1206 | ofs->lower_fs = kcalloc(numlower, sizeof(struct ovl_sb), | |
1207 | GFP_KERNEL); | |
1208 | if (ofs->lower_fs == NULL) | |
1209 | goto out; | |
1210 | ||
520d7c86 MS |
1211 | for (i = 0; i < numlower; i++) { |
1212 | struct vfsmount *mnt; | |
5148626b | 1213 | int fsid; |
520d7c86 | 1214 | |
5148626b AG |
1215 | err = fsid = ovl_get_fsid(ofs, stack[i].mnt->mnt_sb); |
1216 | if (err < 0) | |
520d7c86 | 1217 | goto out; |
520d7c86 MS |
1218 | |
1219 | mnt = clone_private_mount(&stack[i]); | |
1220 | err = PTR_ERR(mnt); | |
1221 | if (IS_ERR(mnt)) { | |
1222 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
520d7c86 MS |
1223 | goto out; |
1224 | } | |
5148626b | 1225 | |
520d7c86 MS |
1226 | /* |
1227 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1228 | * will fail instead of modifying lower fs. | |
1229 | */ | |
1230 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1231 | ||
ad204488 | 1232 | ofs->lower_layers[ofs->numlower].mnt = mnt; |
d583ed7d | 1233 | ofs->lower_layers[ofs->numlower].idx = i + 1; |
5148626b AG |
1234 | ofs->lower_layers[ofs->numlower].fsid = fsid; |
1235 | if (fsid) { | |
1236 | ofs->lower_layers[ofs->numlower].fs = | |
1237 | &ofs->lower_fs[fsid - 1]; | |
1238 | } | |
ad204488 | 1239 | ofs->numlower++; |
520d7c86 | 1240 | } |
e487d889 | 1241 | |
795939a9 AG |
1242 | /* |
1243 | * When all layers on same fs, overlay can use real inode numbers. | |
1244 | * With mount option "xino=on", mounter declares that there are enough | |
1245 | * free high bits in underlying fs to hold the unique fsid. | |
1246 | * If overlayfs does encounter underlying inodes using the high xino | |
1247 | * bits reserved for fsid, it emits a warning and uses the original | |
1248 | * inode number. | |
1249 | */ | |
1250 | if (!ofs->numlowerfs || (ofs->numlowerfs == 1 && !ofs->upper_mnt)) { | |
e487d889 | 1251 | ofs->xino_bits = 0; |
795939a9 AG |
1252 | ofs->config.xino = OVL_XINO_OFF; |
1253 | } else if (ofs->config.xino == OVL_XINO_ON && !ofs->xino_bits) { | |
1254 | /* | |
1255 | * This is a roundup of number of bits needed for numlowerfs+1 | |
1256 | * (i.e. ilog2(numlowerfs+1 - 1) + 1). fsid 0 is reserved for | |
1257 | * upper fs even with non upper overlay. | |
1258 | */ | |
1259 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 31); | |
1260 | ofs->xino_bits = ilog2(ofs->numlowerfs) + 1; | |
1261 | } | |
1262 | ||
1263 | if (ofs->xino_bits) { | |
1264 | pr_info("overlayfs: \"xino\" feature enabled using %d upper inode bits.\n", | |
1265 | ofs->xino_bits); | |
1266 | } | |
e487d889 | 1267 | |
520d7c86 MS |
1268 | err = 0; |
1269 | out: | |
1270 | return err; | |
1271 | } | |
1272 | ||
4155c10a | 1273 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
ad204488 | 1274 | struct ovl_fs *ofs) |
53dbb0b4 MS |
1275 | { |
1276 | int err; | |
1277 | char *lowertmp, *lower; | |
4155c10a MS |
1278 | struct path *stack = NULL; |
1279 | unsigned int stacklen, numlower = 0, i; | |
53dbb0b4 | 1280 | bool remote = false; |
4155c10a | 1281 | struct ovl_entry *oe; |
53dbb0b4 MS |
1282 | |
1283 | err = -ENOMEM; | |
ad204488 | 1284 | lowertmp = kstrdup(ofs->config.lowerdir, GFP_KERNEL); |
53dbb0b4 | 1285 | if (!lowertmp) |
4155c10a | 1286 | goto out_err; |
53dbb0b4 MS |
1287 | |
1288 | err = -EINVAL; | |
1289 | stacklen = ovl_split_lowerdirs(lowertmp); | |
1290 | if (stacklen > OVL_MAX_STACK) { | |
1291 | pr_err("overlayfs: too many lower directories, limit is %d\n", | |
1292 | OVL_MAX_STACK); | |
4155c10a | 1293 | goto out_err; |
ad204488 | 1294 | } else if (!ofs->config.upperdir && stacklen == 1) { |
53dbb0b4 | 1295 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); |
4155c10a | 1296 | goto out_err; |
f168f109 AG |
1297 | } else if (!ofs->config.upperdir && ofs->config.nfs_export && |
1298 | ofs->config.redirect_follow) { | |
1299 | pr_warn("overlayfs: NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); | |
1300 | ofs->config.nfs_export = false; | |
53dbb0b4 MS |
1301 | } |
1302 | ||
1303 | err = -ENOMEM; | |
1304 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
1305 | if (!stack) | |
4155c10a | 1306 | goto out_err; |
53dbb0b4 MS |
1307 | |
1308 | err = -EINVAL; | |
1309 | lower = lowertmp; | |
1310 | for (numlower = 0; numlower < stacklen; numlower++) { | |
ad204488 | 1311 | err = ovl_lower_dir(lower, &stack[numlower], ofs, |
53dbb0b4 MS |
1312 | &sb->s_stack_depth, &remote); |
1313 | if (err) | |
4155c10a | 1314 | goto out_err; |
53dbb0b4 MS |
1315 | |
1316 | lower = strchr(lower, '\0') + 1; | |
1317 | } | |
1318 | ||
1319 | err = -EINVAL; | |
1320 | sb->s_stack_depth++; | |
1321 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1322 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
4155c10a | 1323 | goto out_err; |
53dbb0b4 MS |
1324 | } |
1325 | ||
ad204488 | 1326 | err = ovl_get_lower_layers(ofs, stack, numlower); |
4155c10a MS |
1327 | if (err) |
1328 | goto out_err; | |
1329 | ||
1330 | err = -ENOMEM; | |
1331 | oe = ovl_alloc_entry(numlower); | |
1332 | if (!oe) | |
1333 | goto out_err; | |
1334 | ||
1335 | for (i = 0; i < numlower; i++) { | |
1336 | oe->lowerstack[i].dentry = dget(stack[i].dentry); | |
ad204488 | 1337 | oe->lowerstack[i].layer = &ofs->lower_layers[i]; |
4155c10a | 1338 | } |
53dbb0b4 MS |
1339 | |
1340 | if (remote) | |
1341 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1342 | else | |
1343 | sb->s_d_op = &ovl_dentry_operations; | |
1344 | ||
53dbb0b4 | 1345 | out: |
53dbb0b4 MS |
1346 | for (i = 0; i < numlower; i++) |
1347 | path_put(&stack[i]); | |
1348 | kfree(stack); | |
4155c10a MS |
1349 | kfree(lowertmp); |
1350 | ||
1351 | return oe; | |
1352 | ||
1353 | out_err: | |
1354 | oe = ERR_PTR(err); | |
53dbb0b4 MS |
1355 | goto out; |
1356 | } | |
1357 | ||
e9be9d5e MS |
1358 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1359 | { | |
33006cdf | 1360 | struct path upperpath = { }; |
e9be9d5e | 1361 | struct dentry *root_dentry; |
4155c10a | 1362 | struct ovl_entry *oe; |
ad204488 | 1363 | struct ovl_fs *ofs; |
51f8f3c4 | 1364 | struct cred *cred; |
e9be9d5e MS |
1365 | int err; |
1366 | ||
f45827e8 | 1367 | err = -ENOMEM; |
ad204488 MS |
1368 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
1369 | if (!ofs) | |
e9be9d5e MS |
1370 | goto out; |
1371 | ||
ad204488 | 1372 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1373 | if (!cred) |
1374 | goto out_err; | |
1375 | ||
ad204488 | 1376 | ofs->config.index = ovl_index_def; |
f168f109 | 1377 | ofs->config.nfs_export = ovl_nfs_export_def; |
795939a9 | 1378 | ofs->config.xino = ovl_xino_def(); |
ad204488 | 1379 | err = ovl_parse_opt((char *) data, &ofs->config); |
f45827e8 | 1380 | if (err) |
a9075cdb | 1381 | goto out_err; |
f45827e8 | 1382 | |
e9be9d5e | 1383 | err = -EINVAL; |
ad204488 | 1384 | if (!ofs->config.lowerdir) { |
07f2af7b KK |
1385 | if (!silent) |
1386 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
a9075cdb | 1387 | goto out_err; |
e9be9d5e MS |
1388 | } |
1389 | ||
53a08cb9 | 1390 | sb->s_stack_depth = 0; |
cf9a6784 | 1391 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
e487d889 | 1392 | /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ |
795939a9 AG |
1393 | if (ofs->config.xino != OVL_XINO_OFF) |
1394 | ofs->xino_bits = BITS_PER_LONG - 32; | |
1395 | ||
ad204488 MS |
1396 | if (ofs->config.upperdir) { |
1397 | if (!ofs->config.workdir) { | |
53a08cb9 | 1398 | pr_err("overlayfs: missing 'workdir'\n"); |
a9075cdb | 1399 | goto out_err; |
53a08cb9 | 1400 | } |
e9be9d5e | 1401 | |
ad204488 | 1402 | err = ovl_get_upper(ofs, &upperpath); |
53a08cb9 | 1403 | if (err) |
a9075cdb | 1404 | goto out_err; |
2cac0c00 | 1405 | |
ad204488 | 1406 | err = ovl_get_workdir(ofs, &upperpath); |
8ed61dc3 | 1407 | if (err) |
a9075cdb | 1408 | goto out_err; |
c6fe6254 | 1409 | |
ad204488 | 1410 | if (!ofs->workdir) |
1751e8a6 | 1411 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1412 | |
ad204488 MS |
1413 | sb->s_stack_depth = ofs->upper_mnt->mnt_sb->s_stack_depth; |
1414 | sb->s_time_gran = ofs->upper_mnt->mnt_sb->s_time_gran; | |
c6fe6254 | 1415 | |
e9be9d5e | 1416 | } |
ad204488 | 1417 | oe = ovl_get_lowerstack(sb, ofs); |
4155c10a MS |
1418 | err = PTR_ERR(oe); |
1419 | if (IS_ERR(oe)) | |
a9075cdb | 1420 | goto out_err; |
e9be9d5e | 1421 | |
71cbad7e | 1422 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
ad204488 | 1423 | if (!ofs->upper_mnt) |
1751e8a6 | 1424 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 1425 | |
ad204488 MS |
1426 | if (!(ovl_force_readonly(ofs)) && ofs->config.index) { |
1427 | err = ovl_get_indexdir(ofs, oe, &upperpath); | |
54fb347e | 1428 | if (err) |
4155c10a | 1429 | goto out_free_oe; |
6e88256e | 1430 | |
972d0093 AG |
1431 | /* Force r/o mount with no index dir */ |
1432 | if (!ofs->indexdir) { | |
1433 | dput(ofs->workdir); | |
1434 | ofs->workdir = NULL; | |
1751e8a6 | 1435 | sb->s_flags |= SB_RDONLY; |
972d0093 AG |
1436 | } |
1437 | ||
02bcd157 AG |
1438 | } |
1439 | ||
972d0093 | 1440 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 1441 | if (!ofs->indexdir) { |
ad204488 | 1442 | ofs->config.index = false; |
f168f109 AG |
1443 | if (ofs->upper_mnt && ofs->config.nfs_export) { |
1444 | pr_warn("overlayfs: NFS export requires an index dir, falling back to nfs_export=off.\n"); | |
1445 | ofs->config.nfs_export = false; | |
1446 | } | |
1447 | } | |
02bcd157 | 1448 | |
8383f174 AG |
1449 | if (ofs->config.nfs_export) |
1450 | sb->s_export_op = &ovl_export_operations; | |
1451 | ||
51f8f3c4 KK |
1452 | /* Never override disk quota limits or use reserved space */ |
1453 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1454 | ||
655042cc VG |
1455 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
1456 | sb->s_op = &ovl_super_operations; | |
1457 | sb->s_xattr = ovl_xattr_handlers; | |
ad204488 | 1458 | sb->s_fs_info = ofs; |
de2a4a50 | 1459 | sb->s_flags |= SB_POSIXACL; |
655042cc | 1460 | |
c6fe6254 | 1461 | err = -ENOMEM; |
ca4c8a3a | 1462 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); |
e9be9d5e | 1463 | if (!root_dentry) |
4155c10a | 1464 | goto out_free_oe; |
e9be9d5e | 1465 | |
c62520a8 AG |
1466 | root_dentry->d_fsdata = oe; |
1467 | ||
e9be9d5e | 1468 | mntput(upperpath.mnt); |
f3a15685 | 1469 | if (upperpath.dentry) { |
c62520a8 | 1470 | ovl_dentry_set_upper_alias(root_dentry); |
13c72075 MS |
1471 | if (ovl_is_impuredir(upperpath.dentry)) |
1472 | ovl_set_flag(OVL_IMPURE, d_inode(root_dentry)); | |
f3a15685 | 1473 | } |
e9be9d5e | 1474 | |
b79e05aa AG |
1475 | /* Root is always merge -> can have whiteouts */ |
1476 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root_dentry)); | |
2ca3c148 | 1477 | ovl_dentry_set_flag(OVL_E_CONNECTED, root_dentry); |
09d8b586 MS |
1478 | ovl_inode_init(d_inode(root_dentry), upperpath.dentry, |
1479 | ovl_dentry_lower(root_dentry)); | |
ed06e069 | 1480 | |
e9be9d5e | 1481 | sb->s_root = root_dentry; |
e9be9d5e MS |
1482 | |
1483 | return 0; | |
1484 | ||
4155c10a MS |
1485 | out_free_oe: |
1486 | ovl_entry_stack_free(oe); | |
b9343632 | 1487 | kfree(oe); |
4155c10a | 1488 | out_err: |
e9be9d5e | 1489 | path_put(&upperpath); |
ad204488 | 1490 | ovl_free_fs(ofs); |
e9be9d5e MS |
1491 | out: |
1492 | return err; | |
1493 | } | |
1494 | ||
1495 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1496 | const char *dev_name, void *raw_data) | |
1497 | { | |
1498 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1499 | } | |
1500 | ||
1501 | static struct file_system_type ovl_fs_type = { | |
1502 | .owner = THIS_MODULE, | |
ef94b186 | 1503 | .name = "overlay", |
e9be9d5e MS |
1504 | .mount = ovl_mount, |
1505 | .kill_sb = kill_anon_super, | |
1506 | }; | |
ef94b186 | 1507 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1508 | |
13cf199d AG |
1509 | static void ovl_inode_init_once(void *foo) |
1510 | { | |
1511 | struct ovl_inode *oi = foo; | |
1512 | ||
1513 | inode_init_once(&oi->vfs_inode); | |
1514 | } | |
1515 | ||
e9be9d5e MS |
1516 | static int __init ovl_init(void) |
1517 | { | |
13cf199d AG |
1518 | int err; |
1519 | ||
1520 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1521 | sizeof(struct ovl_inode), 0, | |
1522 | (SLAB_RECLAIM_ACCOUNT| | |
1523 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
1524 | ovl_inode_init_once); | |
1525 | if (ovl_inode_cachep == NULL) | |
1526 | return -ENOMEM; | |
1527 | ||
1528 | err = register_filesystem(&ovl_fs_type); | |
1529 | if (err) | |
1530 | kmem_cache_destroy(ovl_inode_cachep); | |
1531 | ||
1532 | return err; | |
e9be9d5e MS |
1533 | } |
1534 | ||
1535 | static void __exit ovl_exit(void) | |
1536 | { | |
1537 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1538 | |
1539 | /* | |
1540 | * Make sure all delayed rcu free inodes are flushed before we | |
1541 | * destroy cache. | |
1542 | */ | |
1543 | rcu_barrier(); | |
1544 | kmem_cache_destroy(ovl_inode_cachep); | |
1545 | ||
e9be9d5e MS |
1546 | } |
1547 | ||
1548 | module_init(ovl_init); | |
1549 | module_exit(ovl_exit); |