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 | ||
d5791044 VG |
67 | static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); |
68 | module_param_named(metacopy, ovl_metacopy_def, bool, 0644); | |
69 | MODULE_PARM_DESC(ovl_metacopy_def, | |
70 | "Default to on or off for the metadata only copy up feature"); | |
71 | ||
e9be9d5e MS |
72 | static void ovl_dentry_release(struct dentry *dentry) |
73 | { | |
74 | struct ovl_entry *oe = dentry->d_fsdata; | |
75 | ||
76 | if (oe) { | |
4155c10a | 77 | ovl_entry_stack_free(oe); |
e9be9d5e MS |
78 | kfree_rcu(oe, rcu); |
79 | } | |
80 | } | |
81 | ||
2d902671 | 82 | static struct dentry *ovl_d_real(struct dentry *dentry, |
fb16043b | 83 | const struct inode *inode) |
d101a125 MS |
84 | { |
85 | struct dentry *real; | |
86 | ||
e8c985ba MS |
87 | /* It's an overlay file */ |
88 | if (inode && d_inode(dentry) == inode) | |
89 | return dentry; | |
90 | ||
ca4c8a3a | 91 | if (!d_is_reg(dentry)) { |
d101a125 MS |
92 | if (!inode || inode == d_inode(dentry)) |
93 | return dentry; | |
94 | goto bug; | |
95 | } | |
96 | ||
97 | real = ovl_dentry_upper(dentry); | |
2c3d7358 | 98 | if (real && (inode == d_inode(real))) |
d101a125 MS |
99 | return real; |
100 | ||
2c3d7358 VG |
101 | if (real && !inode && ovl_has_upperdata(d_inode(dentry))) |
102 | return real; | |
103 | ||
104 | real = ovl_dentry_lowerdata(dentry); | |
d101a125 MS |
105 | if (!real) |
106 | goto bug; | |
107 | ||
c4fcfc16 | 108 | /* Handle recursion */ |
fb16043b | 109 | real = d_real(real, inode); |
c4fcfc16 | 110 | |
d101a125 MS |
111 | if (!inode || inode == d_inode(real)) |
112 | return real; | |
d101a125 | 113 | bug: |
656189d2 | 114 | WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, |
d101a125 MS |
115 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); |
116 | return dentry; | |
117 | } | |
118 | ||
7c03b5d4 MS |
119 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
120 | { | |
121 | struct ovl_entry *oe = dentry->d_fsdata; | |
122 | unsigned int i; | |
123 | int ret = 1; | |
124 | ||
125 | for (i = 0; i < oe->numlower; i++) { | |
126 | struct dentry *d = oe->lowerstack[i].dentry; | |
127 | ||
128 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
129 | ret = d->d_op->d_revalidate(d, flags); | |
130 | if (ret < 0) | |
131 | return ret; | |
132 | if (!ret) { | |
133 | if (!(flags & LOOKUP_RCU)) | |
134 | d_invalidate(d); | |
135 | return -ESTALE; | |
136 | } | |
137 | } | |
138 | } | |
139 | return 1; | |
140 | } | |
141 | ||
142 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
143 | { | |
144 | struct ovl_entry *oe = dentry->d_fsdata; | |
145 | unsigned int i; | |
146 | int ret = 1; | |
147 | ||
148 | for (i = 0; i < oe->numlower; i++) { | |
149 | struct dentry *d = oe->lowerstack[i].dentry; | |
150 | ||
151 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
152 | ret = d->d_op->d_weak_revalidate(d, flags); | |
153 | if (ret <= 0) | |
154 | break; | |
155 | } | |
156 | } | |
157 | return ret; | |
158 | } | |
159 | ||
e9be9d5e MS |
160 | static const struct dentry_operations ovl_dentry_operations = { |
161 | .d_release = ovl_dentry_release, | |
d101a125 | 162 | .d_real = ovl_d_real, |
e9be9d5e MS |
163 | }; |
164 | ||
7c03b5d4 MS |
165 | static const struct dentry_operations ovl_reval_dentry_operations = { |
166 | .d_release = ovl_dentry_release, | |
d101a125 | 167 | .d_real = ovl_d_real, |
7c03b5d4 MS |
168 | .d_revalidate = ovl_dentry_revalidate, |
169 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
170 | }; | |
171 | ||
13cf199d AG |
172 | static struct kmem_cache *ovl_inode_cachep; |
173 | ||
174 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
175 | { | |
176 | struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); | |
177 | ||
b3885bd6 HN |
178 | if (!oi) |
179 | return NULL; | |
180 | ||
04a01ac7 | 181 | oi->cache = NULL; |
cf31c463 | 182 | oi->redirect = NULL; |
04a01ac7 | 183 | oi->version = 0; |
13c72075 | 184 | oi->flags = 0; |
09d8b586 | 185 | oi->__upperdentry = NULL; |
25b7713a | 186 | oi->lower = NULL; |
2664bd08 | 187 | oi->lowerdata = NULL; |
a015dafc | 188 | mutex_init(&oi->lock); |
25b7713a | 189 | |
13cf199d AG |
190 | return &oi->vfs_inode; |
191 | } | |
192 | ||
193 | static void ovl_i_callback(struct rcu_head *head) | |
194 | { | |
195 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
196 | ||
197 | kmem_cache_free(ovl_inode_cachep, OVL_I(inode)); | |
198 | } | |
199 | ||
200 | static void ovl_destroy_inode(struct inode *inode) | |
201 | { | |
09d8b586 MS |
202 | struct ovl_inode *oi = OVL_I(inode); |
203 | ||
204 | dput(oi->__upperdentry); | |
31747eda | 205 | iput(oi->lower); |
2664bd08 VG |
206 | if (S_ISDIR(inode->i_mode)) |
207 | ovl_dir_cache_free(inode); | |
208 | else | |
209 | iput(oi->lowerdata); | |
cf31c463 | 210 | kfree(oi->redirect); |
a015dafc | 211 | mutex_destroy(&oi->lock); |
09d8b586 | 212 | |
13cf199d AG |
213 | call_rcu(&inode->i_rcu, ovl_i_callback); |
214 | } | |
215 | ||
ad204488 | 216 | static void ovl_free_fs(struct ovl_fs *ofs) |
e9be9d5e | 217 | { |
dd662667 | 218 | unsigned i; |
e9be9d5e | 219 | |
ad204488 MS |
220 | dput(ofs->indexdir); |
221 | dput(ofs->workdir); | |
222 | if (ofs->workdir_locked) | |
223 | ovl_inuse_unlock(ofs->workbasedir); | |
224 | dput(ofs->workbasedir); | |
225 | if (ofs->upperdir_locked) | |
226 | ovl_inuse_unlock(ofs->upper_mnt->mnt_root); | |
227 | mntput(ofs->upper_mnt); | |
5148626b | 228 | for (i = 0; i < ofs->numlower; i++) |
ad204488 | 229 | mntput(ofs->lower_layers[i].mnt); |
5148626b AG |
230 | for (i = 0; i < ofs->numlowerfs; i++) |
231 | free_anon_bdev(ofs->lower_fs[i].pseudo_dev); | |
ad204488 | 232 | kfree(ofs->lower_layers); |
5148626b | 233 | kfree(ofs->lower_fs); |
ad204488 MS |
234 | |
235 | kfree(ofs->config.lowerdir); | |
236 | kfree(ofs->config.upperdir); | |
237 | kfree(ofs->config.workdir); | |
438c84c2 | 238 | kfree(ofs->config.redirect_mode); |
ad204488 MS |
239 | if (ofs->creator_cred) |
240 | put_cred(ofs->creator_cred); | |
241 | kfree(ofs); | |
e9be9d5e MS |
242 | } |
243 | ||
a9075cdb MS |
244 | static void ovl_put_super(struct super_block *sb) |
245 | { | |
246 | struct ovl_fs *ofs = sb->s_fs_info; | |
247 | ||
248 | ovl_free_fs(ofs); | |
249 | } | |
250 | ||
e8d4bfe3 | 251 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
252 | static int ovl_sync_fs(struct super_block *sb, int wait) |
253 | { | |
ad204488 | 254 | struct ovl_fs *ofs = sb->s_fs_info; |
e593b2bf AG |
255 | struct super_block *upper_sb; |
256 | int ret; | |
257 | ||
ad204488 | 258 | if (!ofs->upper_mnt) |
e593b2bf | 259 | return 0; |
e8d4bfe3 CX |
260 | |
261 | /* | |
262 | * If this is a sync(2) call or an emergency sync, all the super blocks | |
263 | * will be iterated, including upper_sb, so no need to do anything. | |
264 | * | |
265 | * If this is a syncfs(2) call, then we do need to call | |
266 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
267 | * called with wait == 1. | |
268 | */ | |
269 | if (!wait) | |
e593b2bf AG |
270 | return 0; |
271 | ||
e8d4bfe3 CX |
272 | upper_sb = ofs->upper_mnt->mnt_sb; |
273 | ||
e593b2bf | 274 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 275 | ret = sync_filesystem(upper_sb); |
e593b2bf | 276 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 277 | |
e593b2bf AG |
278 | return ret; |
279 | } | |
280 | ||
cc259639 AW |
281 | /** |
282 | * ovl_statfs | |
283 | * @sb: The overlayfs super block | |
284 | * @buf: The struct kstatfs to fill in with stats | |
285 | * | |
286 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 287 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
288 | */ |
289 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
290 | { | |
291 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
292 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
293 | struct path path; | |
294 | int err; | |
295 | ||
4ebc5818 | 296 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
297 | |
298 | err = vfs_statfs(&path, buf); | |
299 | if (!err) { | |
6b2d5fe4 | 300 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
301 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
302 | } | |
303 | ||
304 | return err; | |
305 | } | |
306 | ||
02bcd157 | 307 | /* Will this overlay be forced to mount/remount ro? */ |
ad204488 | 308 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
02bcd157 | 309 | { |
ad204488 | 310 | return (!ofs->upper_mnt || !ofs->workdir); |
02bcd157 AG |
311 | } |
312 | ||
438c84c2 MS |
313 | static const char *ovl_redirect_mode_def(void) |
314 | { | |
315 | return ovl_redirect_dir_def ? "on" : "off"; | |
316 | } | |
317 | ||
795939a9 AG |
318 | enum { |
319 | OVL_XINO_OFF, | |
320 | OVL_XINO_AUTO, | |
321 | OVL_XINO_ON, | |
322 | }; | |
323 | ||
324 | static const char * const ovl_xino_str[] = { | |
325 | "off", | |
326 | "auto", | |
327 | "on", | |
328 | }; | |
329 | ||
330 | static inline int ovl_xino_def(void) | |
331 | { | |
332 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; | |
333 | } | |
334 | ||
f45827e8 EZ |
335 | /** |
336 | * ovl_show_options | |
337 | * | |
338 | * Prints the mount options for a given superblock. | |
339 | * Returns zero; does not fail. | |
340 | */ | |
341 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
342 | { | |
343 | struct super_block *sb = dentry->d_sb; | |
ad204488 | 344 | struct ovl_fs *ofs = sb->s_fs_info; |
f45827e8 | 345 | |
ad204488 MS |
346 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
347 | if (ofs->config.upperdir) { | |
348 | seq_show_option(m, "upperdir", ofs->config.upperdir); | |
349 | seq_show_option(m, "workdir", ofs->config.workdir); | |
53a08cb9 | 350 | } |
ad204488 | 351 | if (ofs->config.default_permissions) |
8d3095f4 | 352 | seq_puts(m, ",default_permissions"); |
438c84c2 MS |
353 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
354 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); | |
ad204488 | 355 | if (ofs->config.index != ovl_index_def) |
438c84c2 | 356 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
f168f109 AG |
357 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
358 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? | |
359 | "on" : "off"); | |
795939a9 AG |
360 | if (ofs->config.xino != ovl_xino_def()) |
361 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); | |
d5791044 VG |
362 | if (ofs->config.metacopy != ovl_metacopy_def) |
363 | seq_printf(m, ",metacopy=%s", | |
364 | ofs->config.metacopy ? "on" : "off"); | |
f45827e8 EZ |
365 | return 0; |
366 | } | |
367 | ||
3cdf6fe9 SL |
368 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
369 | { | |
ad204488 | 370 | struct ovl_fs *ofs = sb->s_fs_info; |
3cdf6fe9 | 371 | |
1751e8a6 | 372 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
3cdf6fe9 SL |
373 | return -EROFS; |
374 | ||
375 | return 0; | |
376 | } | |
377 | ||
e9be9d5e | 378 | static const struct super_operations ovl_super_operations = { |
13cf199d AG |
379 | .alloc_inode = ovl_alloc_inode, |
380 | .destroy_inode = ovl_destroy_inode, | |
381 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 382 | .put_super = ovl_put_super, |
e593b2bf | 383 | .sync_fs = ovl_sync_fs, |
cc259639 | 384 | .statfs = ovl_statfs, |
f45827e8 | 385 | .show_options = ovl_show_options, |
3cdf6fe9 | 386 | .remount_fs = ovl_remount, |
e9be9d5e MS |
387 | }; |
388 | ||
389 | enum { | |
390 | OPT_LOWERDIR, | |
391 | OPT_UPPERDIR, | |
392 | OPT_WORKDIR, | |
8d3095f4 | 393 | OPT_DEFAULT_PERMISSIONS, |
438c84c2 | 394 | OPT_REDIRECT_DIR, |
02bcd157 AG |
395 | OPT_INDEX_ON, |
396 | OPT_INDEX_OFF, | |
f168f109 AG |
397 | OPT_NFS_EXPORT_ON, |
398 | OPT_NFS_EXPORT_OFF, | |
795939a9 AG |
399 | OPT_XINO_ON, |
400 | OPT_XINO_OFF, | |
401 | OPT_XINO_AUTO, | |
d5791044 VG |
402 | OPT_METACOPY_ON, |
403 | OPT_METACOPY_OFF, | |
e9be9d5e MS |
404 | OPT_ERR, |
405 | }; | |
406 | ||
407 | static const match_table_t ovl_tokens = { | |
408 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
409 | {OPT_UPPERDIR, "upperdir=%s"}, | |
410 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 411 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
438c84c2 | 412 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
02bcd157 AG |
413 | {OPT_INDEX_ON, "index=on"}, |
414 | {OPT_INDEX_OFF, "index=off"}, | |
f168f109 AG |
415 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
416 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, | |
795939a9 AG |
417 | {OPT_XINO_ON, "xino=on"}, |
418 | {OPT_XINO_OFF, "xino=off"}, | |
419 | {OPT_XINO_AUTO, "xino=auto"}, | |
d5791044 VG |
420 | {OPT_METACOPY_ON, "metacopy=on"}, |
421 | {OPT_METACOPY_OFF, "metacopy=off"}, | |
e9be9d5e MS |
422 | {OPT_ERR, NULL} |
423 | }; | |
424 | ||
91c77947 MS |
425 | static char *ovl_next_opt(char **s) |
426 | { | |
427 | char *sbegin = *s; | |
428 | char *p; | |
429 | ||
430 | if (sbegin == NULL) | |
431 | return NULL; | |
432 | ||
433 | for (p = sbegin; *p; p++) { | |
434 | if (*p == '\\') { | |
435 | p++; | |
436 | if (!*p) | |
437 | break; | |
438 | } else if (*p == ',') { | |
439 | *p = '\0'; | |
440 | *s = p + 1; | |
441 | return sbegin; | |
442 | } | |
443 | } | |
444 | *s = NULL; | |
445 | return sbegin; | |
446 | } | |
447 | ||
438c84c2 MS |
448 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
449 | { | |
450 | if (strcmp(mode, "on") == 0) { | |
451 | config->redirect_dir = true; | |
452 | /* | |
453 | * Does not make sense to have redirect creation without | |
454 | * redirect following. | |
455 | */ | |
456 | config->redirect_follow = true; | |
457 | } else if (strcmp(mode, "follow") == 0) { | |
458 | config->redirect_follow = true; | |
459 | } else if (strcmp(mode, "off") == 0) { | |
460 | if (ovl_redirect_always_follow) | |
461 | config->redirect_follow = true; | |
462 | } else if (strcmp(mode, "nofollow") != 0) { | |
463 | pr_err("overlayfs: bad mount option \"redirect_dir=%s\"\n", | |
464 | mode); | |
465 | return -EINVAL; | |
466 | } | |
467 | ||
468 | return 0; | |
469 | } | |
470 | ||
e9be9d5e MS |
471 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
472 | { | |
473 | char *p; | |
d5791044 | 474 | int err; |
d47748e5 | 475 | bool metacopy_opt = false, redirect_opt = false; |
e9be9d5e | 476 | |
438c84c2 MS |
477 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
478 | if (!config->redirect_mode) | |
479 | return -ENOMEM; | |
480 | ||
91c77947 | 481 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
482 | int token; |
483 | substring_t args[MAX_OPT_ARGS]; | |
484 | ||
485 | if (!*p) | |
486 | continue; | |
487 | ||
488 | token = match_token(p, ovl_tokens, args); | |
489 | switch (token) { | |
490 | case OPT_UPPERDIR: | |
491 | kfree(config->upperdir); | |
492 | config->upperdir = match_strdup(&args[0]); | |
493 | if (!config->upperdir) | |
494 | return -ENOMEM; | |
495 | break; | |
496 | ||
497 | case OPT_LOWERDIR: | |
498 | kfree(config->lowerdir); | |
499 | config->lowerdir = match_strdup(&args[0]); | |
500 | if (!config->lowerdir) | |
501 | return -ENOMEM; | |
502 | break; | |
503 | ||
504 | case OPT_WORKDIR: | |
505 | kfree(config->workdir); | |
506 | config->workdir = match_strdup(&args[0]); | |
507 | if (!config->workdir) | |
508 | return -ENOMEM; | |
509 | break; | |
510 | ||
8d3095f4 MS |
511 | case OPT_DEFAULT_PERMISSIONS: |
512 | config->default_permissions = true; | |
513 | break; | |
514 | ||
438c84c2 MS |
515 | case OPT_REDIRECT_DIR: |
516 | kfree(config->redirect_mode); | |
517 | config->redirect_mode = match_strdup(&args[0]); | |
518 | if (!config->redirect_mode) | |
519 | return -ENOMEM; | |
d47748e5 | 520 | redirect_opt = true; |
a6c60655 MS |
521 | break; |
522 | ||
02bcd157 AG |
523 | case OPT_INDEX_ON: |
524 | config->index = true; | |
525 | break; | |
526 | ||
527 | case OPT_INDEX_OFF: | |
528 | config->index = false; | |
529 | break; | |
530 | ||
f168f109 AG |
531 | case OPT_NFS_EXPORT_ON: |
532 | config->nfs_export = true; | |
533 | break; | |
534 | ||
535 | case OPT_NFS_EXPORT_OFF: | |
536 | config->nfs_export = false; | |
537 | break; | |
538 | ||
795939a9 AG |
539 | case OPT_XINO_ON: |
540 | config->xino = OVL_XINO_ON; | |
541 | break; | |
542 | ||
543 | case OPT_XINO_OFF: | |
544 | config->xino = OVL_XINO_OFF; | |
545 | break; | |
546 | ||
547 | case OPT_XINO_AUTO: | |
548 | config->xino = OVL_XINO_AUTO; | |
549 | break; | |
550 | ||
d5791044 VG |
551 | case OPT_METACOPY_ON: |
552 | config->metacopy = true; | |
d47748e5 | 553 | metacopy_opt = true; |
d5791044 VG |
554 | break; |
555 | ||
556 | case OPT_METACOPY_OFF: | |
557 | config->metacopy = false; | |
558 | break; | |
559 | ||
e9be9d5e | 560 | default: |
bead55ef | 561 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
562 | return -EINVAL; |
563 | } | |
564 | } | |
71cbad7e | 565 | |
566 | /* Workdir is useless in non-upper mount */ | |
567 | if (!config->upperdir && config->workdir) { | |
568 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
569 | config->workdir); | |
570 | kfree(config->workdir); | |
571 | config->workdir = NULL; | |
572 | } | |
573 | ||
d5791044 VG |
574 | err = ovl_parse_redirect_mode(config, config->redirect_mode); |
575 | if (err) | |
576 | return err; | |
577 | ||
d47748e5 MS |
578 | /* |
579 | * This is to make the logic below simpler. It doesn't make any other | |
580 | * difference, since config->redirect_dir is only used for upper. | |
581 | */ | |
582 | if (!config->upperdir && config->redirect_follow) | |
583 | config->redirect_dir = true; | |
584 | ||
585 | /* Resolve metacopy -> redirect_dir dependency */ | |
586 | if (config->metacopy && !config->redirect_dir) { | |
587 | if (metacopy_opt && redirect_opt) { | |
588 | pr_err("overlayfs: conflicting options: metacopy=on,redirect_dir=%s\n", | |
589 | config->redirect_mode); | |
590 | return -EINVAL; | |
591 | } | |
592 | if (redirect_opt) { | |
593 | /* | |
594 | * There was an explicit redirect_dir=... that resulted | |
595 | * in this conflict. | |
596 | */ | |
597 | pr_info("overlayfs: disabling metacopy due to redirect_dir=%s\n", | |
598 | config->redirect_mode); | |
599 | config->metacopy = false; | |
600 | } else { | |
601 | /* Automatically enable redirect otherwise. */ | |
602 | config->redirect_follow = config->redirect_dir = true; | |
603 | } | |
d5791044 VG |
604 | } |
605 | ||
606 | return 0; | |
e9be9d5e MS |
607 | } |
608 | ||
609 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 610 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 611 | |
ad204488 | 612 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 613 | const char *name, bool persist) |
e9be9d5e | 614 | { |
ad204488 MS |
615 | struct inode *dir = ofs->workbasedir->d_inode; |
616 | struct vfsmount *mnt = ofs->upper_mnt; | |
e9be9d5e MS |
617 | struct dentry *work; |
618 | int err; | |
619 | bool retried = false; | |
6b8aa129 | 620 | bool locked = false; |
e9be9d5e | 621 | |
5955102c | 622 | inode_lock_nested(dir, I_MUTEX_PARENT); |
6b8aa129 AG |
623 | locked = true; |
624 | ||
e9be9d5e | 625 | retry: |
ad204488 | 626 | work = lookup_one_len(name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
627 | |
628 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
629 | struct iattr attr = { |
630 | .ia_valid = ATTR_MODE, | |
32a3d848 | 631 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 632 | }; |
e9be9d5e MS |
633 | |
634 | if (work->d_inode) { | |
635 | err = -EEXIST; | |
636 | if (retried) | |
637 | goto out_dput; | |
638 | ||
6b8aa129 AG |
639 | if (persist) |
640 | goto out_unlock; | |
641 | ||
e9be9d5e | 642 | retried = true; |
eea2fb48 | 643 | ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e MS |
644 | dput(work); |
645 | goto retry; | |
646 | } | |
647 | ||
95a1c815 MS |
648 | work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); |
649 | err = PTR_ERR(work); | |
650 | if (IS_ERR(work)) | |
651 | goto out_err; | |
c11b9fdd | 652 | |
cb348edb MS |
653 | /* |
654 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
655 | * | |
656 | * a) success (there was a POSIX ACL xattr and was removed) | |
657 | * b) -ENODATA (there was no POSIX ACL xattr) | |
658 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
659 | * | |
660 | * There are various other error values that could effectively | |
661 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
662 | * if the xattr name is too long), but the set of filesystems | |
663 | * allowed as upper are limited to "normal" ones, where checking | |
664 | * for the above two errors is sufficient. | |
665 | */ | |
c11b9fdd | 666 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 667 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
668 | goto out_dput; |
669 | ||
670 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 671 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
672 | goto out_dput; |
673 | ||
674 | /* Clear any inherited mode bits */ | |
675 | inode_lock(work->d_inode); | |
676 | err = notify_change(work, &attr, NULL); | |
677 | inode_unlock(work->d_inode); | |
678 | if (err) | |
679 | goto out_dput; | |
6b8aa129 AG |
680 | } else { |
681 | err = PTR_ERR(work); | |
682 | goto out_err; | |
e9be9d5e MS |
683 | } |
684 | out_unlock: | |
6b8aa129 AG |
685 | if (locked) |
686 | inode_unlock(dir); | |
e9be9d5e MS |
687 | |
688 | return work; | |
689 | ||
690 | out_dput: | |
691 | dput(work); | |
6b8aa129 AG |
692 | out_err: |
693 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", | |
ad204488 | 694 | ofs->config.workdir, name, -err); |
6b8aa129 | 695 | work = NULL; |
e9be9d5e MS |
696 | goto out_unlock; |
697 | } | |
698 | ||
91c77947 MS |
699 | static void ovl_unescape(char *s) |
700 | { | |
701 | char *d = s; | |
702 | ||
703 | for (;; s++, d++) { | |
704 | if (*s == '\\') | |
705 | s++; | |
706 | *d = *s; | |
707 | if (!*s) | |
708 | break; | |
709 | } | |
710 | } | |
711 | ||
ab508822 MS |
712 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
713 | { | |
a78d9f0d | 714 | int err = -EINVAL; |
ab508822 | 715 | |
a78d9f0d MS |
716 | if (!*name) { |
717 | pr_err("overlayfs: empty lowerdir\n"); | |
718 | goto out; | |
719 | } | |
ab508822 MS |
720 | err = kern_path(name, LOOKUP_FOLLOW, path); |
721 | if (err) { | |
722 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
723 | goto out; | |
724 | } | |
725 | err = -EINVAL; | |
7c03b5d4 | 726 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
727 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
728 | goto out_put; | |
729 | } | |
2b8c30e9 | 730 | if (!d_is_dir(path->dentry)) { |
ab508822 MS |
731 | pr_err("overlayfs: '%s' not a directory\n", name); |
732 | goto out_put; | |
733 | } | |
734 | return 0; | |
735 | ||
736 | out_put: | |
8aafcb59 | 737 | path_put_init(path); |
ab508822 MS |
738 | out: |
739 | return err; | |
740 | } | |
741 | ||
742 | static int ovl_mount_dir(const char *name, struct path *path) | |
743 | { | |
744 | int err = -ENOMEM; | |
745 | char *tmp = kstrdup(name, GFP_KERNEL); | |
746 | ||
747 | if (tmp) { | |
748 | ovl_unescape(tmp); | |
749 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
750 | |
751 | if (!err) | |
752 | if (ovl_dentry_remote(path->dentry)) { | |
753 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
754 | tmp); | |
8aafcb59 | 755 | path_put_init(path); |
7c03b5d4 MS |
756 | err = -EINVAL; |
757 | } | |
ab508822 MS |
758 | kfree(tmp); |
759 | } | |
760 | return err; | |
761 | } | |
762 | ||
6b2d5fe4 MS |
763 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
764 | const char *name) | |
ab508822 | 765 | { |
ab508822 | 766 | struct kstatfs statfs; |
6b2d5fe4 MS |
767 | int err = vfs_statfs(path, &statfs); |
768 | ||
769 | if (err) | |
770 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
771 | else | |
772 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
773 | ||
774 | return err; | |
775 | } | |
776 | ||
777 | static int ovl_lower_dir(const char *name, struct path *path, | |
778 | struct ovl_fs *ofs, int *stack_depth, bool *remote) | |
779 | { | |
e487d889 | 780 | int fh_type; |
6b2d5fe4 | 781 | int err; |
ab508822 | 782 | |
a78d9f0d | 783 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
784 | if (err) |
785 | goto out; | |
786 | ||
6b2d5fe4 MS |
787 | err = ovl_check_namelen(path, ofs, name); |
788 | if (err) | |
ab508822 | 789 | goto out_put; |
6b2d5fe4 | 790 | |
ab508822 MS |
791 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
792 | ||
7c03b5d4 MS |
793 | if (ovl_dentry_remote(path->dentry)) |
794 | *remote = true; | |
795 | ||
02bcd157 | 796 | /* |
f168f109 AG |
797 | * The inodes index feature and NFS export need to encode and decode |
798 | * file handles, so they require that all layers support them. | |
02bcd157 | 799 | */ |
e487d889 | 800 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 801 | if ((ofs->config.nfs_export || |
e487d889 | 802 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 803 | ofs->config.index = false; |
f168f109 AG |
804 | ofs->config.nfs_export = false; |
805 | pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", | |
806 | name); | |
02bcd157 AG |
807 | } |
808 | ||
e487d889 AG |
809 | /* Check if lower fs has 32bit inode numbers */ |
810 | if (fh_type != FILEID_INO32_GEN) | |
811 | ofs->xino_bits = 0; | |
812 | ||
ab508822 MS |
813 | return 0; |
814 | ||
815 | out_put: | |
8aafcb59 | 816 | path_put_init(path); |
ab508822 MS |
817 | out: |
818 | return err; | |
819 | } | |
820 | ||
e9be9d5e MS |
821 | /* Workdir should not be subdir of upperdir and vice versa */ |
822 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
823 | { | |
824 | bool ok = false; | |
825 | ||
826 | if (workdir != upperdir) { | |
827 | ok = (lock_rename(workdir, upperdir) == NULL); | |
828 | unlock_rename(workdir, upperdir); | |
829 | } | |
830 | return ok; | |
831 | } | |
832 | ||
a78d9f0d MS |
833 | static unsigned int ovl_split_lowerdirs(char *str) |
834 | { | |
835 | unsigned int ctr = 1; | |
836 | char *s, *d; | |
837 | ||
838 | for (s = d = str;; s++, d++) { | |
839 | if (*s == '\\') { | |
840 | s++; | |
841 | } else if (*s == ':') { | |
842 | *d = '\0'; | |
843 | ctr++; | |
844 | continue; | |
845 | } | |
846 | *d = *s; | |
847 | if (!*s) | |
848 | break; | |
849 | } | |
850 | return ctr; | |
851 | } | |
852 | ||
0eb45fc3 AG |
853 | static int __maybe_unused |
854 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
855 | struct dentry *dentry, struct inode *inode, | |
856 | const char *name, void *buffer, size_t size) | |
857 | { | |
1d88f183 | 858 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
0eb45fc3 AG |
859 | } |
860 | ||
0c97be22 AG |
861 | static int __maybe_unused |
862 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
863 | struct dentry *dentry, struct inode *inode, | |
864 | const char *name, const void *value, | |
865 | size_t size, int flags) | |
d837a49b MS |
866 | { |
867 | struct dentry *workdir = ovl_workdir(dentry); | |
09d8b586 | 868 | struct inode *realinode = ovl_inode_real(inode); |
d837a49b MS |
869 | struct posix_acl *acl = NULL; |
870 | int err; | |
871 | ||
872 | /* Check that everything is OK before copy-up */ | |
873 | if (value) { | |
874 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
875 | if (IS_ERR(acl)) | |
876 | return PTR_ERR(acl); | |
877 | } | |
878 | err = -EOPNOTSUPP; | |
879 | if (!IS_POSIXACL(d_inode(workdir))) | |
880 | goto out_acl_release; | |
881 | if (!realinode->i_op->set_acl) | |
882 | goto out_acl_release; | |
883 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
884 | err = acl ? -EACCES : 0; | |
885 | goto out_acl_release; | |
886 | } | |
887 | err = -EPERM; | |
888 | if (!inode_owner_or_capable(inode)) | |
889 | goto out_acl_release; | |
890 | ||
891 | posix_acl_release(acl); | |
892 | ||
fd3220d3 MS |
893 | /* |
894 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
895 | * be done with mounter's capabilities and so that won't do it for us). | |
896 | */ | |
897 | if (unlikely(inode->i_mode & S_ISGID) && | |
898 | handler->flags == ACL_TYPE_ACCESS && | |
899 | !in_group_p(inode->i_gid) && | |
900 | !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { | |
901 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; | |
902 | ||
903 | err = ovl_setattr(dentry, &iattr); | |
904 | if (err) | |
905 | return err; | |
906 | } | |
907 | ||
1d88f183 | 908 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
ce31513a | 909 | if (!err) |
09d8b586 | 910 | ovl_copyattr(ovl_inode_real(inode), inode); |
ce31513a MS |
911 | |
912 | return err; | |
d837a49b MS |
913 | |
914 | out_acl_release: | |
915 | posix_acl_release(acl); | |
916 | return err; | |
917 | } | |
918 | ||
0eb45fc3 AG |
919 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
920 | struct dentry *dentry, struct inode *inode, | |
921 | const char *name, void *buffer, size_t size) | |
922 | { | |
48fab5d7 | 923 | return -EOPNOTSUPP; |
0eb45fc3 AG |
924 | } |
925 | ||
d837a49b MS |
926 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
927 | struct dentry *dentry, struct inode *inode, | |
928 | const char *name, const void *value, | |
929 | size_t size, int flags) | |
930 | { | |
48fab5d7 | 931 | return -EOPNOTSUPP; |
d837a49b MS |
932 | } |
933 | ||
0eb45fc3 AG |
934 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
935 | struct dentry *dentry, struct inode *inode, | |
936 | const char *name, void *buffer, size_t size) | |
937 | { | |
1d88f183 | 938 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
939 | } |
940 | ||
0e585ccc AG |
941 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
942 | struct dentry *dentry, struct inode *inode, | |
943 | const char *name, const void *value, | |
944 | size_t size, int flags) | |
945 | { | |
1d88f183 | 946 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
947 | } |
948 | ||
0c97be22 AG |
949 | static const struct xattr_handler __maybe_unused |
950 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
951 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
952 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 953 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
954 | .set = ovl_posix_acl_xattr_set, |
955 | }; | |
956 | ||
0c97be22 AG |
957 | static const struct xattr_handler __maybe_unused |
958 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
959 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
960 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 961 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
962 | .set = ovl_posix_acl_xattr_set, |
963 | }; | |
964 | ||
965 | static const struct xattr_handler ovl_own_xattr_handler = { | |
966 | .prefix = OVL_XATTR_PREFIX, | |
0eb45fc3 | 967 | .get = ovl_own_xattr_get, |
d837a49b MS |
968 | .set = ovl_own_xattr_set, |
969 | }; | |
970 | ||
971 | static const struct xattr_handler ovl_other_xattr_handler = { | |
972 | .prefix = "", /* catch all */ | |
0eb45fc3 | 973 | .get = ovl_other_xattr_get, |
d837a49b MS |
974 | .set = ovl_other_xattr_set, |
975 | }; | |
976 | ||
977 | static const struct xattr_handler *ovl_xattr_handlers[] = { | |
0c97be22 | 978 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
979 | &ovl_posix_acl_access_xattr_handler, |
980 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 981 | #endif |
d837a49b MS |
982 | &ovl_own_xattr_handler, |
983 | &ovl_other_xattr_handler, | |
984 | NULL | |
985 | }; | |
986 | ||
ad204488 | 987 | static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath) |
6ee8acf0 | 988 | { |
5064975e | 989 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
990 | int err; |
991 | ||
ad204488 | 992 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
6ee8acf0 MS |
993 | if (err) |
994 | goto out; | |
995 | ||
996 | /* Upper fs should not be r/o */ | |
997 | if (sb_rdonly(upperpath->mnt->mnt_sb)) { | |
998 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
999 | err = -EINVAL; | |
1000 | goto out; | |
1001 | } | |
1002 | ||
ad204488 | 1003 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
1004 | if (err) |
1005 | goto out; | |
1006 | ||
5064975e MS |
1007 | upper_mnt = clone_private_mount(upperpath); |
1008 | err = PTR_ERR(upper_mnt); | |
1009 | if (IS_ERR(upper_mnt)) { | |
1010 | pr_err("overlayfs: failed to clone upperpath\n"); | |
1011 | goto out; | |
1012 | } | |
1013 | ||
1014 | /* Don't inherit atime flags */ | |
1015 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
ad204488 | 1016 | ofs->upper_mnt = upper_mnt; |
8c25741a MS |
1017 | |
1018 | err = -EBUSY; | |
1019 | if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) { | |
1020 | ofs->upperdir_locked = true; | |
1021 | } else if (ofs->config.index) { | |
1022 | pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n"); | |
1023 | goto out; | |
1024 | } else { | |
1025 | pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
1026 | } | |
1027 | ||
6ee8acf0 MS |
1028 | err = 0; |
1029 | out: | |
1030 | return err; | |
1031 | } | |
1032 | ||
ad204488 | 1033 | static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) |
8ed61dc3 | 1034 | { |
2ba9d57e | 1035 | struct vfsmount *mnt = ofs->upper_mnt; |
8ed61dc3 | 1036 | struct dentry *temp; |
e487d889 | 1037 | int fh_type; |
8ed61dc3 MS |
1038 | int err; |
1039 | ||
2ba9d57e AG |
1040 | err = mnt_want_write(mnt); |
1041 | if (err) | |
1042 | return err; | |
1043 | ||
ad204488 MS |
1044 | ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
1045 | if (!ofs->workdir) | |
2ba9d57e | 1046 | goto out; |
8ed61dc3 MS |
1047 | |
1048 | /* | |
1049 | * Upper should support d_type, else whiteouts are visible. Given | |
1050 | * workdir and upper are on same fs, we can do iterate_dir() on | |
1051 | * workdir. This check requires successful creation of workdir in | |
1052 | * previous step. | |
1053 | */ | |
1054 | err = ovl_check_d_type_supported(workpath); | |
1055 | if (err < 0) | |
2ba9d57e | 1056 | goto out; |
8ed61dc3 MS |
1057 | |
1058 | /* | |
1059 | * We allowed this configuration and don't want to break users over | |
1060 | * kernel upgrade. So warn instead of erroring out. | |
1061 | */ | |
1062 | if (!err) | |
1063 | pr_warn("overlayfs: upper fs needs to support d_type.\n"); | |
1064 | ||
1065 | /* Check if upper/work fs supports O_TMPFILE */ | |
ad204488 MS |
1066 | temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); |
1067 | ofs->tmpfile = !IS_ERR(temp); | |
1068 | if (ofs->tmpfile) | |
8ed61dc3 MS |
1069 | dput(temp); |
1070 | else | |
1071 | pr_warn("overlayfs: upper fs does not support tmpfile.\n"); | |
1072 | ||
1073 | /* | |
1074 | * Check if upper/work fs supports trusted.overlay.* xattr | |
1075 | */ | |
ad204488 | 1076 | err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1, 0); |
8ed61dc3 | 1077 | if (err) { |
ad204488 | 1078 | ofs->noxattr = true; |
a683737b | 1079 | ofs->config.index = false; |
d5791044 VG |
1080 | ofs->config.metacopy = false; |
1081 | pr_warn("overlayfs: upper fs does not support xattr, falling back to index=off and metacopy=off.\n"); | |
2ba9d57e | 1082 | err = 0; |
8ed61dc3 | 1083 | } else { |
ad204488 | 1084 | vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
1085 | } |
1086 | ||
1087 | /* Check if upper/work fs supports file handles */ | |
e487d889 AG |
1088 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
1089 | if (ofs->config.index && !fh_type) { | |
ad204488 | 1090 | ofs->config.index = false; |
8ed61dc3 MS |
1091 | pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); |
1092 | } | |
1093 | ||
e487d889 AG |
1094 | /* Check if upper fs has 32bit inode numbers */ |
1095 | if (fh_type != FILEID_INO32_GEN) | |
1096 | ofs->xino_bits = 0; | |
1097 | ||
f168f109 AG |
1098 | /* NFS export of r/w mount depends on index */ |
1099 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1100 | pr_warn("overlayfs: NFS export requires \"index=on\", falling back to nfs_export=off.\n"); | |
1101 | ofs->config.nfs_export = false; | |
1102 | } | |
2ba9d57e AG |
1103 | out: |
1104 | mnt_drop_write(mnt); | |
1105 | return err; | |
8ed61dc3 MS |
1106 | } |
1107 | ||
ad204488 | 1108 | static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath) |
520d7c86 MS |
1109 | { |
1110 | int err; | |
bca44b52 | 1111 | struct path workpath = { }; |
520d7c86 | 1112 | |
ad204488 | 1113 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
520d7c86 MS |
1114 | if (err) |
1115 | goto out; | |
1116 | ||
1117 | err = -EINVAL; | |
bca44b52 | 1118 | if (upperpath->mnt != workpath.mnt) { |
520d7c86 MS |
1119 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); |
1120 | goto out; | |
1121 | } | |
bca44b52 | 1122 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
520d7c86 MS |
1123 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); |
1124 | goto out; | |
1125 | } | |
1126 | ||
8c25741a MS |
1127 | ofs->workbasedir = dget(workpath.dentry); |
1128 | ||
520d7c86 | 1129 | err = -EBUSY; |
8c25741a | 1130 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 MS |
1131 | ofs->workdir_locked = true; |
1132 | } else if (ofs->config.index) { | |
520d7c86 MS |
1133 | pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n"); |
1134 | goto out; | |
1135 | } else { | |
1136 | pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); | |
1137 | } | |
1138 | ||
ad204488 | 1139 | err = ovl_make_workdir(ofs, &workpath); |
bca44b52 MS |
1140 | if (err) |
1141 | goto out; | |
1142 | ||
520d7c86 MS |
1143 | err = 0; |
1144 | out: | |
bca44b52 MS |
1145 | path_put(&workpath); |
1146 | ||
520d7c86 MS |
1147 | return err; |
1148 | } | |
1149 | ||
ad204488 | 1150 | static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe, |
95e6d417 | 1151 | struct path *upperpath) |
f7e3a7d9 | 1152 | { |
2ba9d57e | 1153 | struct vfsmount *mnt = ofs->upper_mnt; |
f7e3a7d9 MS |
1154 | int err; |
1155 | ||
2ba9d57e AG |
1156 | err = mnt_want_write(mnt); |
1157 | if (err) | |
1158 | return err; | |
1159 | ||
f7e3a7d9 | 1160 | /* Verify lower root is upper root origin */ |
d9768076 | 1161 | err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry, |
05122443 | 1162 | true); |
f7e3a7d9 MS |
1163 | if (err) { |
1164 | pr_err("overlayfs: failed to verify upper root origin\n"); | |
1165 | goto out; | |
1166 | } | |
1167 | ||
ad204488 MS |
1168 | ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
1169 | if (ofs->indexdir) { | |
ad1d615c AG |
1170 | /* |
1171 | * Verify upper root is exclusively associated with index dir. | |
1172 | * Older kernels stored upper fh in "trusted.overlay.origin" | |
1173 | * xattr. If that xattr exists, verify that it is a match to | |
1174 | * upper dir file handle. In any case, verify or set xattr | |
1175 | * "trusted.overlay.upper" to indicate that index may have | |
1176 | * directory entries. | |
1177 | */ | |
1178 | if (ovl_check_origin_xattr(ofs->indexdir)) { | |
1179 | err = ovl_verify_set_fh(ofs->indexdir, OVL_XATTR_ORIGIN, | |
1180 | upperpath->dentry, true, false); | |
1181 | if (err) | |
1182 | pr_err("overlayfs: failed to verify index dir 'origin' xattr\n"); | |
1183 | } | |
1184 | err = ovl_verify_upper(ofs->indexdir, upperpath->dentry, true); | |
f7e3a7d9 | 1185 | if (err) |
ad1d615c | 1186 | pr_err("overlayfs: failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
1187 | |
1188 | /* Cleanup bad/stale/orphan index entries */ | |
1189 | if (!err) | |
1eff1a1d | 1190 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 1191 | } |
ad204488 | 1192 | if (err || !ofs->indexdir) |
f7e3a7d9 MS |
1193 | pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
1194 | ||
1195 | out: | |
2ba9d57e | 1196 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
1197 | return err; |
1198 | } | |
1199 | ||
9df085f3 AG |
1200 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
1201 | { | |
1202 | unsigned int i; | |
1203 | ||
1204 | if (!ofs->config.nfs_export && !(ofs->config.index && ofs->upper_mnt)) | |
1205 | return true; | |
1206 | ||
1207 | for (i = 0; i < ofs->numlowerfs; i++) { | |
1208 | /* | |
1209 | * We use uuid to associate an overlay lower file handle with a | |
1210 | * lower layer, so we can accept lower fs with null uuid as long | |
1211 | * as all lower layers with null uuid are on the same fs. | |
1212 | */ | |
1213 | if (uuid_equal(&ofs->lower_fs[i].sb->s_uuid, uuid)) | |
1214 | return false; | |
1215 | } | |
1216 | return true; | |
1217 | } | |
1218 | ||
5148626b | 1219 | /* Get a unique fsid for the layer */ |
9df085f3 | 1220 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 1221 | { |
9df085f3 | 1222 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
1223 | unsigned int i; |
1224 | dev_t dev; | |
1225 | int err; | |
1226 | ||
1227 | /* fsid 0 is reserved for upper fs even with non upper overlay */ | |
1228 | if (ofs->upper_mnt && ofs->upper_mnt->mnt_sb == sb) | |
1229 | return 0; | |
1230 | ||
1231 | for (i = 0; i < ofs->numlowerfs; i++) { | |
1232 | if (ofs->lower_fs[i].sb == sb) | |
1233 | return i + 1; | |
1234 | } | |
1235 | ||
9df085f3 AG |
1236 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
1237 | ofs->config.index = false; | |
1238 | ofs->config.nfs_export = false; | |
1239 | pr_warn("overlayfs: %s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n", | |
1240 | uuid_is_null(&sb->s_uuid) ? "null" : "conflicting", | |
1241 | path->dentry); | |
1242 | } | |
1243 | ||
5148626b AG |
1244 | err = get_anon_bdev(&dev); |
1245 | if (err) { | |
1246 | pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n"); | |
1247 | return err; | |
1248 | } | |
1249 | ||
1250 | ofs->lower_fs[ofs->numlowerfs].sb = sb; | |
1251 | ofs->lower_fs[ofs->numlowerfs].pseudo_dev = dev; | |
1252 | ofs->numlowerfs++; | |
1253 | ||
1254 | return ofs->numlowerfs; | |
1255 | } | |
1256 | ||
ad204488 | 1257 | static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack, |
520d7c86 MS |
1258 | unsigned int numlower) |
1259 | { | |
1260 | int err; | |
1261 | unsigned int i; | |
1262 | ||
1263 | err = -ENOMEM; | |
ad204488 | 1264 | ofs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer), |
520d7c86 | 1265 | GFP_KERNEL); |
ad204488 | 1266 | if (ofs->lower_layers == NULL) |
520d7c86 | 1267 | goto out; |
5148626b AG |
1268 | |
1269 | ofs->lower_fs = kcalloc(numlower, sizeof(struct ovl_sb), | |
1270 | GFP_KERNEL); | |
1271 | if (ofs->lower_fs == NULL) | |
1272 | goto out; | |
1273 | ||
520d7c86 MS |
1274 | for (i = 0; i < numlower; i++) { |
1275 | struct vfsmount *mnt; | |
5148626b | 1276 | int fsid; |
520d7c86 | 1277 | |
9df085f3 | 1278 | err = fsid = ovl_get_fsid(ofs, &stack[i]); |
5148626b | 1279 | if (err < 0) |
520d7c86 | 1280 | goto out; |
520d7c86 MS |
1281 | |
1282 | mnt = clone_private_mount(&stack[i]); | |
1283 | err = PTR_ERR(mnt); | |
1284 | if (IS_ERR(mnt)) { | |
1285 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
520d7c86 MS |
1286 | goto out; |
1287 | } | |
5148626b | 1288 | |
520d7c86 MS |
1289 | /* |
1290 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1291 | * will fail instead of modifying lower fs. | |
1292 | */ | |
1293 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1294 | ||
ad204488 | 1295 | ofs->lower_layers[ofs->numlower].mnt = mnt; |
d583ed7d | 1296 | ofs->lower_layers[ofs->numlower].idx = i + 1; |
5148626b AG |
1297 | ofs->lower_layers[ofs->numlower].fsid = fsid; |
1298 | if (fsid) { | |
1299 | ofs->lower_layers[ofs->numlower].fs = | |
1300 | &ofs->lower_fs[fsid - 1]; | |
1301 | } | |
ad204488 | 1302 | ofs->numlower++; |
520d7c86 | 1303 | } |
e487d889 | 1304 | |
795939a9 AG |
1305 | /* |
1306 | * When all layers on same fs, overlay can use real inode numbers. | |
1307 | * With mount option "xino=on", mounter declares that there are enough | |
1308 | * free high bits in underlying fs to hold the unique fsid. | |
1309 | * If overlayfs does encounter underlying inodes using the high xino | |
1310 | * bits reserved for fsid, it emits a warning and uses the original | |
1311 | * inode number. | |
1312 | */ | |
1313 | if (!ofs->numlowerfs || (ofs->numlowerfs == 1 && !ofs->upper_mnt)) { | |
e487d889 | 1314 | ofs->xino_bits = 0; |
795939a9 AG |
1315 | ofs->config.xino = OVL_XINO_OFF; |
1316 | } else if (ofs->config.xino == OVL_XINO_ON && !ofs->xino_bits) { | |
1317 | /* | |
1318 | * This is a roundup of number of bits needed for numlowerfs+1 | |
1319 | * (i.e. ilog2(numlowerfs+1 - 1) + 1). fsid 0 is reserved for | |
1320 | * upper fs even with non upper overlay. | |
1321 | */ | |
1322 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 31); | |
1323 | ofs->xino_bits = ilog2(ofs->numlowerfs) + 1; | |
1324 | } | |
1325 | ||
1326 | if (ofs->xino_bits) { | |
1327 | pr_info("overlayfs: \"xino\" feature enabled using %d upper inode bits.\n", | |
1328 | ofs->xino_bits); | |
1329 | } | |
e487d889 | 1330 | |
520d7c86 MS |
1331 | err = 0; |
1332 | out: | |
1333 | return err; | |
1334 | } | |
1335 | ||
4155c10a | 1336 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
ad204488 | 1337 | struct ovl_fs *ofs) |
53dbb0b4 MS |
1338 | { |
1339 | int err; | |
1340 | char *lowertmp, *lower; | |
4155c10a MS |
1341 | struct path *stack = NULL; |
1342 | unsigned int stacklen, numlower = 0, i; | |
53dbb0b4 | 1343 | bool remote = false; |
4155c10a | 1344 | struct ovl_entry *oe; |
53dbb0b4 MS |
1345 | |
1346 | err = -ENOMEM; | |
ad204488 | 1347 | lowertmp = kstrdup(ofs->config.lowerdir, GFP_KERNEL); |
53dbb0b4 | 1348 | if (!lowertmp) |
4155c10a | 1349 | goto out_err; |
53dbb0b4 MS |
1350 | |
1351 | err = -EINVAL; | |
1352 | stacklen = ovl_split_lowerdirs(lowertmp); | |
1353 | if (stacklen > OVL_MAX_STACK) { | |
1354 | pr_err("overlayfs: too many lower directories, limit is %d\n", | |
1355 | OVL_MAX_STACK); | |
4155c10a | 1356 | goto out_err; |
ad204488 | 1357 | } else if (!ofs->config.upperdir && stacklen == 1) { |
53dbb0b4 | 1358 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); |
4155c10a | 1359 | goto out_err; |
f168f109 AG |
1360 | } else if (!ofs->config.upperdir && ofs->config.nfs_export && |
1361 | ofs->config.redirect_follow) { | |
1362 | pr_warn("overlayfs: NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); | |
1363 | ofs->config.nfs_export = false; | |
53dbb0b4 MS |
1364 | } |
1365 | ||
1366 | err = -ENOMEM; | |
1367 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
1368 | if (!stack) | |
4155c10a | 1369 | goto out_err; |
53dbb0b4 MS |
1370 | |
1371 | err = -EINVAL; | |
1372 | lower = lowertmp; | |
1373 | for (numlower = 0; numlower < stacklen; numlower++) { | |
ad204488 | 1374 | err = ovl_lower_dir(lower, &stack[numlower], ofs, |
53dbb0b4 MS |
1375 | &sb->s_stack_depth, &remote); |
1376 | if (err) | |
4155c10a | 1377 | goto out_err; |
53dbb0b4 MS |
1378 | |
1379 | lower = strchr(lower, '\0') + 1; | |
1380 | } | |
1381 | ||
1382 | err = -EINVAL; | |
1383 | sb->s_stack_depth++; | |
1384 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1385 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
4155c10a | 1386 | goto out_err; |
53dbb0b4 MS |
1387 | } |
1388 | ||
ad204488 | 1389 | err = ovl_get_lower_layers(ofs, stack, numlower); |
4155c10a MS |
1390 | if (err) |
1391 | goto out_err; | |
1392 | ||
1393 | err = -ENOMEM; | |
1394 | oe = ovl_alloc_entry(numlower); | |
1395 | if (!oe) | |
1396 | goto out_err; | |
1397 | ||
1398 | for (i = 0; i < numlower; i++) { | |
1399 | oe->lowerstack[i].dentry = dget(stack[i].dentry); | |
ad204488 | 1400 | oe->lowerstack[i].layer = &ofs->lower_layers[i]; |
4155c10a | 1401 | } |
53dbb0b4 MS |
1402 | |
1403 | if (remote) | |
1404 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1405 | else | |
1406 | sb->s_d_op = &ovl_dentry_operations; | |
1407 | ||
53dbb0b4 | 1408 | out: |
53dbb0b4 MS |
1409 | for (i = 0; i < numlower; i++) |
1410 | path_put(&stack[i]); | |
1411 | kfree(stack); | |
4155c10a MS |
1412 | kfree(lowertmp); |
1413 | ||
1414 | return oe; | |
1415 | ||
1416 | out_err: | |
1417 | oe = ERR_PTR(err); | |
53dbb0b4 MS |
1418 | goto out; |
1419 | } | |
1420 | ||
e9be9d5e MS |
1421 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1422 | { | |
33006cdf | 1423 | struct path upperpath = { }; |
e9be9d5e | 1424 | struct dentry *root_dentry; |
4155c10a | 1425 | struct ovl_entry *oe; |
ad204488 | 1426 | struct ovl_fs *ofs; |
51f8f3c4 | 1427 | struct cred *cred; |
e9be9d5e MS |
1428 | int err; |
1429 | ||
f45827e8 | 1430 | err = -ENOMEM; |
ad204488 MS |
1431 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
1432 | if (!ofs) | |
e9be9d5e MS |
1433 | goto out; |
1434 | ||
ad204488 | 1435 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1436 | if (!cred) |
1437 | goto out_err; | |
1438 | ||
ad204488 | 1439 | ofs->config.index = ovl_index_def; |
f168f109 | 1440 | ofs->config.nfs_export = ovl_nfs_export_def; |
795939a9 | 1441 | ofs->config.xino = ovl_xino_def(); |
d5791044 | 1442 | ofs->config.metacopy = ovl_metacopy_def; |
ad204488 | 1443 | err = ovl_parse_opt((char *) data, &ofs->config); |
f45827e8 | 1444 | if (err) |
a9075cdb | 1445 | goto out_err; |
f45827e8 | 1446 | |
e9be9d5e | 1447 | err = -EINVAL; |
ad204488 | 1448 | if (!ofs->config.lowerdir) { |
07f2af7b KK |
1449 | if (!silent) |
1450 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
a9075cdb | 1451 | goto out_err; |
e9be9d5e MS |
1452 | } |
1453 | ||
53a08cb9 | 1454 | sb->s_stack_depth = 0; |
cf9a6784 | 1455 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
e487d889 | 1456 | /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ |
795939a9 AG |
1457 | if (ofs->config.xino != OVL_XINO_OFF) |
1458 | ofs->xino_bits = BITS_PER_LONG - 32; | |
1459 | ||
ad204488 MS |
1460 | if (ofs->config.upperdir) { |
1461 | if (!ofs->config.workdir) { | |
53a08cb9 | 1462 | pr_err("overlayfs: missing 'workdir'\n"); |
a9075cdb | 1463 | goto out_err; |
53a08cb9 | 1464 | } |
e9be9d5e | 1465 | |
ad204488 | 1466 | err = ovl_get_upper(ofs, &upperpath); |
53a08cb9 | 1467 | if (err) |
a9075cdb | 1468 | goto out_err; |
2cac0c00 | 1469 | |
ad204488 | 1470 | err = ovl_get_workdir(ofs, &upperpath); |
8ed61dc3 | 1471 | if (err) |
a9075cdb | 1472 | goto out_err; |
c6fe6254 | 1473 | |
ad204488 | 1474 | if (!ofs->workdir) |
1751e8a6 | 1475 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1476 | |
ad204488 MS |
1477 | sb->s_stack_depth = ofs->upper_mnt->mnt_sb->s_stack_depth; |
1478 | sb->s_time_gran = ofs->upper_mnt->mnt_sb->s_time_gran; | |
c6fe6254 | 1479 | |
e9be9d5e | 1480 | } |
ad204488 | 1481 | oe = ovl_get_lowerstack(sb, ofs); |
4155c10a MS |
1482 | err = PTR_ERR(oe); |
1483 | if (IS_ERR(oe)) | |
a9075cdb | 1484 | goto out_err; |
e9be9d5e | 1485 | |
71cbad7e | 1486 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
ad204488 | 1487 | if (!ofs->upper_mnt) |
1751e8a6 | 1488 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 1489 | |
ad204488 MS |
1490 | if (!(ovl_force_readonly(ofs)) && ofs->config.index) { |
1491 | err = ovl_get_indexdir(ofs, oe, &upperpath); | |
54fb347e | 1492 | if (err) |
4155c10a | 1493 | goto out_free_oe; |
6e88256e | 1494 | |
972d0093 AG |
1495 | /* Force r/o mount with no index dir */ |
1496 | if (!ofs->indexdir) { | |
1497 | dput(ofs->workdir); | |
1498 | ofs->workdir = NULL; | |
1751e8a6 | 1499 | sb->s_flags |= SB_RDONLY; |
972d0093 AG |
1500 | } |
1501 | ||
02bcd157 AG |
1502 | } |
1503 | ||
972d0093 | 1504 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 1505 | if (!ofs->indexdir) { |
ad204488 | 1506 | ofs->config.index = false; |
f168f109 AG |
1507 | if (ofs->upper_mnt && ofs->config.nfs_export) { |
1508 | pr_warn("overlayfs: NFS export requires an index dir, falling back to nfs_export=off.\n"); | |
1509 | ofs->config.nfs_export = false; | |
1510 | } | |
1511 | } | |
02bcd157 | 1512 | |
d5791044 VG |
1513 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1514 | pr_warn("overlayfs: NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); | |
1515 | ofs->config.nfs_export = false; | |
1516 | } | |
1517 | ||
8383f174 AG |
1518 | if (ofs->config.nfs_export) |
1519 | sb->s_export_op = &ovl_export_operations; | |
1520 | ||
51f8f3c4 KK |
1521 | /* Never override disk quota limits or use reserved space */ |
1522 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1523 | ||
655042cc VG |
1524 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
1525 | sb->s_op = &ovl_super_operations; | |
1526 | sb->s_xattr = ovl_xattr_handlers; | |
ad204488 | 1527 | sb->s_fs_info = ofs; |
de2a4a50 | 1528 | sb->s_flags |= SB_POSIXACL; |
655042cc | 1529 | |
c6fe6254 | 1530 | err = -ENOMEM; |
ca4c8a3a | 1531 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); |
e9be9d5e | 1532 | if (!root_dentry) |
4155c10a | 1533 | goto out_free_oe; |
e9be9d5e | 1534 | |
c62520a8 AG |
1535 | root_dentry->d_fsdata = oe; |
1536 | ||
e9be9d5e | 1537 | mntput(upperpath.mnt); |
f3a15685 | 1538 | if (upperpath.dentry) { |
c62520a8 | 1539 | ovl_dentry_set_upper_alias(root_dentry); |
13c72075 MS |
1540 | if (ovl_is_impuredir(upperpath.dentry)) |
1541 | ovl_set_flag(OVL_IMPURE, d_inode(root_dentry)); | |
f3a15685 | 1542 | } |
e9be9d5e | 1543 | |
b79e05aa AG |
1544 | /* Root is always merge -> can have whiteouts */ |
1545 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root_dentry)); | |
2ca3c148 | 1546 | ovl_dentry_set_flag(OVL_E_CONNECTED, root_dentry); |
0c288874 | 1547 | ovl_set_upperdata(d_inode(root_dentry)); |
09d8b586 | 1548 | ovl_inode_init(d_inode(root_dentry), upperpath.dentry, |
2664bd08 | 1549 | ovl_dentry_lower(root_dentry), NULL); |
ed06e069 | 1550 | |
e9be9d5e | 1551 | sb->s_root = root_dentry; |
e9be9d5e MS |
1552 | |
1553 | return 0; | |
1554 | ||
4155c10a MS |
1555 | out_free_oe: |
1556 | ovl_entry_stack_free(oe); | |
b9343632 | 1557 | kfree(oe); |
4155c10a | 1558 | out_err: |
e9be9d5e | 1559 | path_put(&upperpath); |
ad204488 | 1560 | ovl_free_fs(ofs); |
e9be9d5e MS |
1561 | out: |
1562 | return err; | |
1563 | } | |
1564 | ||
1565 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1566 | const char *dev_name, void *raw_data) | |
1567 | { | |
1568 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1569 | } | |
1570 | ||
1571 | static struct file_system_type ovl_fs_type = { | |
1572 | .owner = THIS_MODULE, | |
ef94b186 | 1573 | .name = "overlay", |
e9be9d5e MS |
1574 | .mount = ovl_mount, |
1575 | .kill_sb = kill_anon_super, | |
1576 | }; | |
ef94b186 | 1577 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1578 | |
13cf199d AG |
1579 | static void ovl_inode_init_once(void *foo) |
1580 | { | |
1581 | struct ovl_inode *oi = foo; | |
1582 | ||
1583 | inode_init_once(&oi->vfs_inode); | |
1584 | } | |
1585 | ||
e9be9d5e MS |
1586 | static int __init ovl_init(void) |
1587 | { | |
13cf199d AG |
1588 | int err; |
1589 | ||
1590 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1591 | sizeof(struct ovl_inode), 0, | |
1592 | (SLAB_RECLAIM_ACCOUNT| | |
1593 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
1594 | ovl_inode_init_once); | |
1595 | if (ovl_inode_cachep == NULL) | |
1596 | return -ENOMEM; | |
1597 | ||
1598 | err = register_filesystem(&ovl_fs_type); | |
1599 | if (err) | |
1600 | kmem_cache_destroy(ovl_inode_cachep); | |
1601 | ||
1602 | return err; | |
e9be9d5e MS |
1603 | } |
1604 | ||
1605 | static void __exit ovl_exit(void) | |
1606 | { | |
1607 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1608 | |
1609 | /* | |
1610 | * Make sure all delayed rcu free inodes are flushed before we | |
1611 | * destroy cache. | |
1612 | */ | |
1613 | rcu_barrier(); | |
1614 | kmem_cache_destroy(ovl_inode_cachep); | |
1615 | ||
e9be9d5e MS |
1616 | } |
1617 | ||
1618 | module_init(ovl_init); | |
1619 | module_exit(ovl_exit); |