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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e9be9d5e MS |
2 | /* |
3 | * | |
4 | * Copyright (C) 2011 Novell Inc. | |
e9be9d5e MS |
5 | */ |
6 | ||
5b825c3a | 7 | #include <uapi/linux/magic.h> |
e9be9d5e MS |
8 | #include <linux/fs.h> |
9 | #include <linux/namei.h> | |
10 | #include <linux/xattr.h> | |
e9be9d5e | 11 | #include <linux/mount.h> |
e9be9d5e MS |
12 | #include <linux/parser.h> |
13 | #include <linux/module.h> | |
cc259639 | 14 | #include <linux/statfs.h> |
f45827e8 | 15 | #include <linux/seq_file.h> |
d837a49b | 16 | #include <linux/posix_acl_xattr.h> |
e487d889 | 17 | #include <linux/exportfs.h> |
e9be9d5e MS |
18 | #include "overlayfs.h" |
19 | ||
20 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
21 | MODULE_DESCRIPTION("Overlay filesystem"); | |
22 | MODULE_LICENSE("GPL"); | |
23 | ||
e9be9d5e MS |
24 | |
25 | struct ovl_dir_cache; | |
26 | ||
a78d9f0d MS |
27 | #define OVL_MAX_STACK 500 |
28 | ||
688ea0e5 MS |
29 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
30 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); | |
253e7483 | 31 | MODULE_PARM_DESC(redirect_dir, |
688ea0e5 | 32 | "Default to on or off for the redirect_dir feature"); |
e9be9d5e | 33 | |
438c84c2 MS |
34 | static bool ovl_redirect_always_follow = |
35 | IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); | |
36 | module_param_named(redirect_always_follow, ovl_redirect_always_follow, | |
37 | bool, 0644); | |
253e7483 | 38 | MODULE_PARM_DESC(redirect_always_follow, |
438c84c2 MS |
39 | "Follow redirects even if redirect_dir feature is turned off"); |
40 | ||
02bcd157 AG |
41 | static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); |
42 | module_param_named(index, ovl_index_def, bool, 0644); | |
253e7483 | 43 | MODULE_PARM_DESC(index, |
02bcd157 AG |
44 | "Default to on or off for the inodes index feature"); |
45 | ||
f168f109 AG |
46 | static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); |
47 | module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); | |
253e7483 | 48 | MODULE_PARM_DESC(nfs_export, |
f168f109 AG |
49 | "Default to on or off for the NFS export feature"); |
50 | ||
795939a9 AG |
51 | static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); |
52 | module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); | |
253e7483 | 53 | MODULE_PARM_DESC(xino_auto, |
795939a9 AG |
54 | "Auto enable xino feature"); |
55 | ||
4155c10a MS |
56 | static void ovl_entry_stack_free(struct ovl_entry *oe) |
57 | { | |
58 | unsigned int i; | |
59 | ||
60 | for (i = 0; i < oe->numlower; i++) | |
61 | dput(oe->lowerstack[i].dentry); | |
62 | } | |
63 | ||
d5791044 VG |
64 | static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); |
65 | module_param_named(metacopy, ovl_metacopy_def, bool, 0644); | |
253e7483 | 66 | MODULE_PARM_DESC(metacopy, |
d5791044 VG |
67 | "Default to on or off for the metadata only copy up feature"); |
68 | ||
e9be9d5e MS |
69 | static void ovl_dentry_release(struct dentry *dentry) |
70 | { | |
71 | struct ovl_entry *oe = dentry->d_fsdata; | |
72 | ||
73 | if (oe) { | |
4155c10a | 74 | ovl_entry_stack_free(oe); |
e9be9d5e MS |
75 | kfree_rcu(oe, rcu); |
76 | } | |
77 | } | |
78 | ||
2d902671 | 79 | static struct dentry *ovl_d_real(struct dentry *dentry, |
fb16043b | 80 | const struct inode *inode) |
d101a125 | 81 | { |
cef4cbff | 82 | struct dentry *real = NULL, *lower; |
d101a125 | 83 | |
e8c985ba MS |
84 | /* It's an overlay file */ |
85 | if (inode && d_inode(dentry) == inode) | |
86 | return dentry; | |
87 | ||
ca4c8a3a | 88 | if (!d_is_reg(dentry)) { |
d101a125 MS |
89 | if (!inode || inode == d_inode(dentry)) |
90 | return dentry; | |
91 | goto bug; | |
92 | } | |
93 | ||
94 | real = ovl_dentry_upper(dentry); | |
2c3d7358 | 95 | if (real && (inode == d_inode(real))) |
d101a125 MS |
96 | return real; |
97 | ||
2c3d7358 VG |
98 | if (real && !inode && ovl_has_upperdata(d_inode(dentry))) |
99 | return real; | |
100 | ||
cef4cbff MS |
101 | lower = ovl_dentry_lowerdata(dentry); |
102 | if (!lower) | |
d101a125 | 103 | goto bug; |
cef4cbff | 104 | real = lower; |
d101a125 | 105 | |
c4fcfc16 | 106 | /* Handle recursion */ |
fb16043b | 107 | real = d_real(real, inode); |
c4fcfc16 | 108 | |
d101a125 MS |
109 | if (!inode || inode == d_inode(real)) |
110 | return real; | |
d101a125 | 111 | bug: |
cef4cbff MS |
112 | WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", |
113 | __func__, dentry, inode ? inode->i_sb->s_id : "NULL", | |
114 | inode ? inode->i_ino : 0, real, | |
115 | real && d_inode(real) ? d_inode(real)->i_ino : 0); | |
d101a125 MS |
116 | return dentry; |
117 | } | |
118 | ||
3bb7df92 | 119 | static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) |
7c03b5d4 | 120 | { |
7c03b5d4 MS |
121 | int ret = 1; |
122 | ||
3bb7df92 MS |
123 | if (weak) { |
124 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) | |
125 | ret = d->d_op->d_weak_revalidate(d, flags); | |
126 | } else if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
127 | ret = d->d_op->d_revalidate(d, flags); | |
128 | if (!ret) { | |
129 | if (!(flags & LOOKUP_RCU)) | |
130 | d_invalidate(d); | |
131 | ret = -ESTALE; | |
7c03b5d4 MS |
132 | } |
133 | } | |
3bb7df92 | 134 | return ret; |
7c03b5d4 MS |
135 | } |
136 | ||
3bb7df92 MS |
137 | static int ovl_dentry_revalidate_common(struct dentry *dentry, |
138 | unsigned int flags, bool weak) | |
7c03b5d4 MS |
139 | { |
140 | struct ovl_entry *oe = dentry->d_fsdata; | |
bccece1e | 141 | struct dentry *upper; |
7c03b5d4 MS |
142 | unsigned int i; |
143 | int ret = 1; | |
144 | ||
bccece1e MS |
145 | upper = ovl_dentry_upper(dentry); |
146 | if (upper) | |
147 | ret = ovl_revalidate_real(upper, flags, weak); | |
148 | ||
3bb7df92 MS |
149 | for (i = 0; ret > 0 && i < oe->numlower; i++) { |
150 | ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, | |
151 | weak); | |
7c03b5d4 MS |
152 | } |
153 | return ret; | |
154 | } | |
155 | ||
3bb7df92 MS |
156 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
157 | { | |
158 | return ovl_dentry_revalidate_common(dentry, flags, false); | |
159 | } | |
160 | ||
161 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
162 | { | |
163 | return ovl_dentry_revalidate_common(dentry, flags, true); | |
164 | } | |
165 | ||
e9be9d5e MS |
166 | static const struct dentry_operations ovl_dentry_operations = { |
167 | .d_release = ovl_dentry_release, | |
d101a125 | 168 | .d_real = ovl_d_real, |
7c03b5d4 MS |
169 | .d_revalidate = ovl_dentry_revalidate, |
170 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
171 | }; | |
172 | ||
13cf199d AG |
173 | static struct kmem_cache *ovl_inode_cachep; |
174 | ||
175 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
176 | { | |
177 | struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); | |
178 | ||
b3885bd6 HN |
179 | if (!oi) |
180 | return NULL; | |
181 | ||
04a01ac7 | 182 | oi->cache = NULL; |
cf31c463 | 183 | oi->redirect = NULL; |
04a01ac7 | 184 | oi->version = 0; |
13c72075 | 185 | oi->flags = 0; |
09d8b586 | 186 | oi->__upperdentry = NULL; |
25b7713a | 187 | oi->lower = NULL; |
2664bd08 | 188 | oi->lowerdata = NULL; |
a015dafc | 189 | mutex_init(&oi->lock); |
25b7713a | 190 | |
13cf199d AG |
191 | return &oi->vfs_inode; |
192 | } | |
193 | ||
0b269ded | 194 | static void ovl_free_inode(struct inode *inode) |
13cf199d | 195 | { |
0b269ded | 196 | struct ovl_inode *oi = OVL_I(inode); |
13cf199d | 197 | |
0b269ded AV |
198 | kfree(oi->redirect); |
199 | mutex_destroy(&oi->lock); | |
200 | kmem_cache_free(ovl_inode_cachep, oi); | |
13cf199d AG |
201 | } |
202 | ||
203 | static void ovl_destroy_inode(struct inode *inode) | |
204 | { | |
09d8b586 MS |
205 | struct ovl_inode *oi = OVL_I(inode); |
206 | ||
207 | dput(oi->__upperdentry); | |
31747eda | 208 | iput(oi->lower); |
2664bd08 VG |
209 | if (S_ISDIR(inode->i_mode)) |
210 | ovl_dir_cache_free(inode); | |
211 | else | |
212 | iput(oi->lowerdata); | |
13cf199d AG |
213 | } |
214 | ||
ad204488 | 215 | static void ovl_free_fs(struct ovl_fs *ofs) |
e9be9d5e | 216 | { |
df820f8d | 217 | struct vfsmount **mounts; |
dd662667 | 218 | unsigned i; |
e9be9d5e | 219 | |
0be0bfd2 | 220 | iput(ofs->workbasedir_trap); |
146d62e5 AG |
221 | iput(ofs->indexdir_trap); |
222 | iput(ofs->workdir_trap); | |
c21c839b | 223 | dput(ofs->whiteout); |
ad204488 MS |
224 | dput(ofs->indexdir); |
225 | dput(ofs->workdir); | |
226 | if (ofs->workdir_locked) | |
227 | ovl_inuse_unlock(ofs->workbasedir); | |
228 | dput(ofs->workbasedir); | |
229 | if (ofs->upperdir_locked) | |
08f4c7c8 | 230 | ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); |
df820f8d MS |
231 | |
232 | /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ | |
233 | mounts = (struct vfsmount **) ofs->layers; | |
b8e42a65 | 234 | for (i = 0; i < ofs->numlayer; i++) { |
94375f9d | 235 | iput(ofs->layers[i].trap); |
df820f8d | 236 | mounts[i] = ofs->layers[i].mnt; |
146d62e5 | 237 | } |
df820f8d | 238 | kern_unmount_array(mounts, ofs->numlayer); |
94375f9d | 239 | kfree(ofs->layers); |
b7bf9908 | 240 | for (i = 0; i < ofs->numfs; i++) |
07f1e596 AG |
241 | free_anon_bdev(ofs->fs[i].pseudo_dev); |
242 | kfree(ofs->fs); | |
ad204488 MS |
243 | |
244 | kfree(ofs->config.lowerdir); | |
245 | kfree(ofs->config.upperdir); | |
246 | kfree(ofs->config.workdir); | |
438c84c2 | 247 | kfree(ofs->config.redirect_mode); |
ad204488 MS |
248 | if (ofs->creator_cred) |
249 | put_cred(ofs->creator_cred); | |
250 | kfree(ofs); | |
e9be9d5e MS |
251 | } |
252 | ||
a9075cdb MS |
253 | static void ovl_put_super(struct super_block *sb) |
254 | { | |
255 | struct ovl_fs *ofs = sb->s_fs_info; | |
256 | ||
257 | ovl_free_fs(ofs); | |
258 | } | |
259 | ||
e8d4bfe3 | 260 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
261 | static int ovl_sync_fs(struct super_block *sb, int wait) |
262 | { | |
ad204488 | 263 | struct ovl_fs *ofs = sb->s_fs_info; |
e593b2bf AG |
264 | struct super_block *upper_sb; |
265 | int ret; | |
266 | ||
08f4c7c8 | 267 | if (!ovl_upper_mnt(ofs)) |
e593b2bf | 268 | return 0; |
e8d4bfe3 | 269 | |
c86243b0 VG |
270 | if (!ovl_should_sync(ofs)) |
271 | return 0; | |
e8d4bfe3 | 272 | /* |
32b1924b KK |
273 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
274 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
275 | * |
276 | * If this is a syncfs(2) call, then we do need to call | |
277 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
278 | * called with wait == 1. | |
279 | */ | |
280 | if (!wait) | |
e593b2bf AG |
281 | return 0; |
282 | ||
08f4c7c8 | 283 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 284 | |
e593b2bf | 285 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 286 | ret = sync_filesystem(upper_sb); |
e593b2bf | 287 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 288 | |
e593b2bf AG |
289 | return ret; |
290 | } | |
291 | ||
cc259639 AW |
292 | /** |
293 | * ovl_statfs | |
294 | * @sb: The overlayfs super block | |
295 | * @buf: The struct kstatfs to fill in with stats | |
296 | * | |
297 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 298 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
299 | */ |
300 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
301 | { | |
302 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
303 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
304 | struct path path; | |
305 | int err; | |
306 | ||
4ebc5818 | 307 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
308 | |
309 | err = vfs_statfs(&path, buf); | |
310 | if (!err) { | |
6b2d5fe4 | 311 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
312 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
313 | } | |
314 | ||
315 | return err; | |
316 | } | |
317 | ||
02bcd157 | 318 | /* Will this overlay be forced to mount/remount ro? */ |
ad204488 | 319 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
02bcd157 | 320 | { |
08f4c7c8 | 321 | return (!ovl_upper_mnt(ofs) || !ofs->workdir); |
02bcd157 AG |
322 | } |
323 | ||
438c84c2 MS |
324 | static const char *ovl_redirect_mode_def(void) |
325 | { | |
326 | return ovl_redirect_dir_def ? "on" : "off"; | |
327 | } | |
328 | ||
795939a9 AG |
329 | static const char * const ovl_xino_str[] = { |
330 | "off", | |
331 | "auto", | |
332 | "on", | |
333 | }; | |
334 | ||
335 | static inline int ovl_xino_def(void) | |
336 | { | |
337 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; | |
338 | } | |
339 | ||
f45827e8 EZ |
340 | /** |
341 | * ovl_show_options | |
342 | * | |
343 | * Prints the mount options for a given superblock. | |
344 | * Returns zero; does not fail. | |
345 | */ | |
346 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
347 | { | |
348 | struct super_block *sb = dentry->d_sb; | |
ad204488 | 349 | struct ovl_fs *ofs = sb->s_fs_info; |
f45827e8 | 350 | |
ad204488 MS |
351 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
352 | if (ofs->config.upperdir) { | |
353 | seq_show_option(m, "upperdir", ofs->config.upperdir); | |
354 | seq_show_option(m, "workdir", ofs->config.workdir); | |
53a08cb9 | 355 | } |
ad204488 | 356 | if (ofs->config.default_permissions) |
8d3095f4 | 357 | seq_puts(m, ",default_permissions"); |
438c84c2 MS |
358 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
359 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); | |
ad204488 | 360 | if (ofs->config.index != ovl_index_def) |
438c84c2 | 361 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
5830fb6b PT |
362 | if (!ofs->config.uuid) |
363 | seq_puts(m, ",uuid=off"); | |
f168f109 AG |
364 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
365 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? | |
366 | "on" : "off"); | |
0f831ec8 | 367 | if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) |
795939a9 | 368 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); |
d5791044 VG |
369 | if (ofs->config.metacopy != ovl_metacopy_def) |
370 | seq_printf(m, ",metacopy=%s", | |
371 | ofs->config.metacopy ? "on" : "off"); | |
c86243b0 VG |
372 | if (ofs->config.ovl_volatile) |
373 | seq_puts(m, ",volatile"); | |
f45827e8 EZ |
374 | return 0; |
375 | } | |
376 | ||
3cdf6fe9 SL |
377 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
378 | { | |
ad204488 | 379 | struct ovl_fs *ofs = sb->s_fs_info; |
399c109d CX |
380 | struct super_block *upper_sb; |
381 | int ret = 0; | |
3cdf6fe9 | 382 | |
1751e8a6 | 383 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
3cdf6fe9 SL |
384 | return -EROFS; |
385 | ||
399c109d | 386 | if (*flags & SB_RDONLY && !sb_rdonly(sb)) { |
08f4c7c8 | 387 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
c86243b0 VG |
388 | if (ovl_should_sync(ofs)) { |
389 | down_read(&upper_sb->s_umount); | |
390 | ret = sync_filesystem(upper_sb); | |
391 | up_read(&upper_sb->s_umount); | |
392 | } | |
399c109d CX |
393 | } |
394 | ||
395 | return ret; | |
3cdf6fe9 SL |
396 | } |
397 | ||
e9be9d5e | 398 | static const struct super_operations ovl_super_operations = { |
13cf199d | 399 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 400 | .free_inode = ovl_free_inode, |
13cf199d AG |
401 | .destroy_inode = ovl_destroy_inode, |
402 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 403 | .put_super = ovl_put_super, |
e593b2bf | 404 | .sync_fs = ovl_sync_fs, |
cc259639 | 405 | .statfs = ovl_statfs, |
f45827e8 | 406 | .show_options = ovl_show_options, |
3cdf6fe9 | 407 | .remount_fs = ovl_remount, |
e9be9d5e MS |
408 | }; |
409 | ||
410 | enum { | |
411 | OPT_LOWERDIR, | |
412 | OPT_UPPERDIR, | |
413 | OPT_WORKDIR, | |
8d3095f4 | 414 | OPT_DEFAULT_PERMISSIONS, |
438c84c2 | 415 | OPT_REDIRECT_DIR, |
02bcd157 AG |
416 | OPT_INDEX_ON, |
417 | OPT_INDEX_OFF, | |
5830fb6b PT |
418 | OPT_UUID_ON, |
419 | OPT_UUID_OFF, | |
f168f109 | 420 | OPT_NFS_EXPORT_ON, |
2d2f2d73 | 421 | OPT_USERXATTR, |
f168f109 | 422 | OPT_NFS_EXPORT_OFF, |
795939a9 AG |
423 | OPT_XINO_ON, |
424 | OPT_XINO_OFF, | |
425 | OPT_XINO_AUTO, | |
d5791044 VG |
426 | OPT_METACOPY_ON, |
427 | OPT_METACOPY_OFF, | |
c86243b0 | 428 | OPT_VOLATILE, |
e9be9d5e MS |
429 | OPT_ERR, |
430 | }; | |
431 | ||
432 | static const match_table_t ovl_tokens = { | |
433 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
434 | {OPT_UPPERDIR, "upperdir=%s"}, | |
435 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 436 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
438c84c2 | 437 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
02bcd157 AG |
438 | {OPT_INDEX_ON, "index=on"}, |
439 | {OPT_INDEX_OFF, "index=off"}, | |
2d2f2d73 | 440 | {OPT_USERXATTR, "userxattr"}, |
5830fb6b PT |
441 | {OPT_UUID_ON, "uuid=on"}, |
442 | {OPT_UUID_OFF, "uuid=off"}, | |
f168f109 AG |
443 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
444 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, | |
795939a9 AG |
445 | {OPT_XINO_ON, "xino=on"}, |
446 | {OPT_XINO_OFF, "xino=off"}, | |
447 | {OPT_XINO_AUTO, "xino=auto"}, | |
d5791044 VG |
448 | {OPT_METACOPY_ON, "metacopy=on"}, |
449 | {OPT_METACOPY_OFF, "metacopy=off"}, | |
c86243b0 | 450 | {OPT_VOLATILE, "volatile"}, |
e9be9d5e MS |
451 | {OPT_ERR, NULL} |
452 | }; | |
453 | ||
91c77947 MS |
454 | static char *ovl_next_opt(char **s) |
455 | { | |
456 | char *sbegin = *s; | |
457 | char *p; | |
458 | ||
459 | if (sbegin == NULL) | |
460 | return NULL; | |
461 | ||
462 | for (p = sbegin; *p; p++) { | |
463 | if (*p == '\\') { | |
464 | p++; | |
465 | if (!*p) | |
466 | break; | |
467 | } else if (*p == ',') { | |
468 | *p = '\0'; | |
469 | *s = p + 1; | |
470 | return sbegin; | |
471 | } | |
472 | } | |
473 | *s = NULL; | |
474 | return sbegin; | |
475 | } | |
476 | ||
438c84c2 MS |
477 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
478 | { | |
479 | if (strcmp(mode, "on") == 0) { | |
480 | config->redirect_dir = true; | |
481 | /* | |
482 | * Does not make sense to have redirect creation without | |
483 | * redirect following. | |
484 | */ | |
485 | config->redirect_follow = true; | |
486 | } else if (strcmp(mode, "follow") == 0) { | |
487 | config->redirect_follow = true; | |
488 | } else if (strcmp(mode, "off") == 0) { | |
489 | if (ovl_redirect_always_follow) | |
490 | config->redirect_follow = true; | |
491 | } else if (strcmp(mode, "nofollow") != 0) { | |
1bd0a3ae | 492 | pr_err("bad mount option \"redirect_dir=%s\"\n", |
438c84c2 MS |
493 | mode); |
494 | return -EINVAL; | |
495 | } | |
496 | ||
497 | return 0; | |
498 | } | |
499 | ||
e9be9d5e MS |
500 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
501 | { | |
502 | char *p; | |
d5791044 | 503 | int err; |
d47748e5 | 504 | bool metacopy_opt = false, redirect_opt = false; |
b0def88d | 505 | bool nfs_export_opt = false, index_opt = false; |
e9be9d5e | 506 | |
438c84c2 MS |
507 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
508 | if (!config->redirect_mode) | |
509 | return -ENOMEM; | |
510 | ||
91c77947 | 511 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
512 | int token; |
513 | substring_t args[MAX_OPT_ARGS]; | |
514 | ||
515 | if (!*p) | |
516 | continue; | |
517 | ||
518 | token = match_token(p, ovl_tokens, args); | |
519 | switch (token) { | |
520 | case OPT_UPPERDIR: | |
521 | kfree(config->upperdir); | |
522 | config->upperdir = match_strdup(&args[0]); | |
523 | if (!config->upperdir) | |
524 | return -ENOMEM; | |
525 | break; | |
526 | ||
527 | case OPT_LOWERDIR: | |
528 | kfree(config->lowerdir); | |
529 | config->lowerdir = match_strdup(&args[0]); | |
530 | if (!config->lowerdir) | |
531 | return -ENOMEM; | |
532 | break; | |
533 | ||
534 | case OPT_WORKDIR: | |
535 | kfree(config->workdir); | |
536 | config->workdir = match_strdup(&args[0]); | |
537 | if (!config->workdir) | |
538 | return -ENOMEM; | |
539 | break; | |
540 | ||
8d3095f4 MS |
541 | case OPT_DEFAULT_PERMISSIONS: |
542 | config->default_permissions = true; | |
543 | break; | |
544 | ||
438c84c2 MS |
545 | case OPT_REDIRECT_DIR: |
546 | kfree(config->redirect_mode); | |
547 | config->redirect_mode = match_strdup(&args[0]); | |
548 | if (!config->redirect_mode) | |
549 | return -ENOMEM; | |
d47748e5 | 550 | redirect_opt = true; |
a6c60655 MS |
551 | break; |
552 | ||
02bcd157 AG |
553 | case OPT_INDEX_ON: |
554 | config->index = true; | |
b0def88d | 555 | index_opt = true; |
02bcd157 AG |
556 | break; |
557 | ||
558 | case OPT_INDEX_OFF: | |
559 | config->index = false; | |
b0def88d | 560 | index_opt = true; |
02bcd157 AG |
561 | break; |
562 | ||
5830fb6b PT |
563 | case OPT_UUID_ON: |
564 | config->uuid = true; | |
565 | break; | |
566 | ||
567 | case OPT_UUID_OFF: | |
568 | config->uuid = false; | |
569 | break; | |
570 | ||
f168f109 AG |
571 | case OPT_NFS_EXPORT_ON: |
572 | config->nfs_export = true; | |
b0def88d | 573 | nfs_export_opt = true; |
f168f109 AG |
574 | break; |
575 | ||
576 | case OPT_NFS_EXPORT_OFF: | |
577 | config->nfs_export = false; | |
b0def88d | 578 | nfs_export_opt = true; |
f168f109 AG |
579 | break; |
580 | ||
795939a9 AG |
581 | case OPT_XINO_ON: |
582 | config->xino = OVL_XINO_ON; | |
583 | break; | |
584 | ||
585 | case OPT_XINO_OFF: | |
586 | config->xino = OVL_XINO_OFF; | |
587 | break; | |
588 | ||
589 | case OPT_XINO_AUTO: | |
590 | config->xino = OVL_XINO_AUTO; | |
591 | break; | |
592 | ||
d5791044 VG |
593 | case OPT_METACOPY_ON: |
594 | config->metacopy = true; | |
d47748e5 | 595 | metacopy_opt = true; |
d5791044 VG |
596 | break; |
597 | ||
598 | case OPT_METACOPY_OFF: | |
599 | config->metacopy = false; | |
b0def88d | 600 | metacopy_opt = true; |
d5791044 VG |
601 | break; |
602 | ||
c86243b0 VG |
603 | case OPT_VOLATILE: |
604 | config->ovl_volatile = true; | |
605 | break; | |
606 | ||
2d2f2d73 MS |
607 | case OPT_USERXATTR: |
608 | config->userxattr = true; | |
609 | break; | |
610 | ||
e9be9d5e | 611 | default: |
1bd0a3ae | 612 | pr_err("unrecognized mount option \"%s\" or missing value\n", |
613 | p); | |
e9be9d5e MS |
614 | return -EINVAL; |
615 | } | |
616 | } | |
71cbad7e | 617 | |
f0e1266e AG |
618 | /* Workdir/index are useless in non-upper mount */ |
619 | if (!config->upperdir) { | |
620 | if (config->workdir) { | |
621 | pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
622 | config->workdir); | |
623 | kfree(config->workdir); | |
624 | config->workdir = NULL; | |
625 | } | |
626 | if (config->index && index_opt) { | |
627 | pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); | |
628 | index_opt = false; | |
629 | } | |
630 | config->index = false; | |
71cbad7e | 631 | } |
632 | ||
c86243b0 VG |
633 | if (!config->upperdir && config->ovl_volatile) { |
634 | pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); | |
635 | config->ovl_volatile = false; | |
636 | } | |
637 | ||
d5791044 VG |
638 | err = ovl_parse_redirect_mode(config, config->redirect_mode); |
639 | if (err) | |
640 | return err; | |
641 | ||
d47748e5 MS |
642 | /* |
643 | * This is to make the logic below simpler. It doesn't make any other | |
644 | * difference, since config->redirect_dir is only used for upper. | |
645 | */ | |
646 | if (!config->upperdir && config->redirect_follow) | |
647 | config->redirect_dir = true; | |
648 | ||
649 | /* Resolve metacopy -> redirect_dir dependency */ | |
650 | if (config->metacopy && !config->redirect_dir) { | |
651 | if (metacopy_opt && redirect_opt) { | |
1bd0a3ae | 652 | pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", |
d47748e5 MS |
653 | config->redirect_mode); |
654 | return -EINVAL; | |
655 | } | |
656 | if (redirect_opt) { | |
657 | /* | |
658 | * There was an explicit redirect_dir=... that resulted | |
659 | * in this conflict. | |
660 | */ | |
1bd0a3ae | 661 | pr_info("disabling metacopy due to redirect_dir=%s\n", |
d47748e5 MS |
662 | config->redirect_mode); |
663 | config->metacopy = false; | |
664 | } else { | |
665 | /* Automatically enable redirect otherwise. */ | |
666 | config->redirect_follow = config->redirect_dir = true; | |
667 | } | |
d5791044 VG |
668 | } |
669 | ||
b0def88d AG |
670 | /* Resolve nfs_export -> index dependency */ |
671 | if (config->nfs_export && !config->index) { | |
f0e1266e AG |
672 | if (!config->upperdir && config->redirect_follow) { |
673 | pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); | |
674 | config->nfs_export = false; | |
675 | } else if (nfs_export_opt && index_opt) { | |
b0def88d AG |
676 | pr_err("conflicting options: nfs_export=on,index=off\n"); |
677 | return -EINVAL; | |
f0e1266e | 678 | } else if (index_opt) { |
b0def88d AG |
679 | /* |
680 | * There was an explicit index=off that resulted | |
681 | * in this conflict. | |
682 | */ | |
683 | pr_info("disabling nfs_export due to index=off\n"); | |
684 | config->nfs_export = false; | |
685 | } else { | |
686 | /* Automatically enable index otherwise. */ | |
687 | config->index = true; | |
688 | } | |
689 | } | |
690 | ||
691 | /* Resolve nfs_export -> !metacopy dependency */ | |
692 | if (config->nfs_export && config->metacopy) { | |
693 | if (nfs_export_opt && metacopy_opt) { | |
694 | pr_err("conflicting options: nfs_export=on,metacopy=on\n"); | |
695 | return -EINVAL; | |
696 | } | |
697 | if (metacopy_opt) { | |
698 | /* | |
699 | * There was an explicit metacopy=on that resulted | |
700 | * in this conflict. | |
701 | */ | |
702 | pr_info("disabling nfs_export due to metacopy=on\n"); | |
703 | config->nfs_export = false; | |
704 | } else { | |
705 | /* | |
706 | * There was an explicit nfs_export=on that resulted | |
707 | * in this conflict. | |
708 | */ | |
709 | pr_info("disabling metacopy due to nfs_export=on\n"); | |
710 | config->metacopy = false; | |
711 | } | |
712 | } | |
713 | ||
2d2f2d73 MS |
714 | |
715 | /* Resolve userxattr -> !redirect && !metacopy dependency */ | |
716 | if (config->userxattr) { | |
717 | if (config->redirect_follow && redirect_opt) { | |
718 | pr_err("conflicting options: userxattr,redirect_dir=%s\n", | |
719 | config->redirect_mode); | |
720 | return -EINVAL; | |
721 | } | |
722 | if (config->metacopy && metacopy_opt) { | |
723 | pr_err("conflicting options: userxattr,metacopy=on\n"); | |
724 | return -EINVAL; | |
725 | } | |
726 | /* | |
727 | * Silently disable default setting of redirect and metacopy. | |
728 | * This shall be the default in the future as well: these | |
729 | * options must be explicitly enabled if used together with | |
730 | * userxattr. | |
731 | */ | |
732 | config->redirect_dir = config->redirect_follow = false; | |
733 | config->metacopy = false; | |
734 | } | |
735 | ||
d5791044 | 736 | return 0; |
e9be9d5e MS |
737 | } |
738 | ||
739 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 740 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 741 | |
ad204488 | 742 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 743 | const char *name, bool persist) |
e9be9d5e | 744 | { |
ad204488 | 745 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 746 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
747 | struct dentry *work; |
748 | int err; | |
749 | bool retried = false; | |
750 | ||
5955102c | 751 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 752 | retry: |
ad204488 | 753 | work = lookup_one_len(name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
754 | |
755 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
756 | struct iattr attr = { |
757 | .ia_valid = ATTR_MODE, | |
32a3d848 | 758 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 759 | }; |
e9be9d5e MS |
760 | |
761 | if (work->d_inode) { | |
762 | err = -EEXIST; | |
763 | if (retried) | |
764 | goto out_dput; | |
765 | ||
6b8aa129 AG |
766 | if (persist) |
767 | goto out_unlock; | |
768 | ||
e9be9d5e | 769 | retried = true; |
235ce9ed | 770 | err = ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e | 771 | dput(work); |
235ce9ed AG |
772 | if (err == -EINVAL) { |
773 | work = ERR_PTR(err); | |
774 | goto out_unlock; | |
775 | } | |
e9be9d5e MS |
776 | goto retry; |
777 | } | |
778 | ||
95a1c815 MS |
779 | work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); |
780 | err = PTR_ERR(work); | |
781 | if (IS_ERR(work)) | |
782 | goto out_err; | |
c11b9fdd | 783 | |
cb348edb MS |
784 | /* |
785 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
786 | * | |
787 | * a) success (there was a POSIX ACL xattr and was removed) | |
788 | * b) -ENODATA (there was no POSIX ACL xattr) | |
789 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
790 | * | |
791 | * There are various other error values that could effectively | |
792 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
793 | * if the xattr name is too long), but the set of filesystems | |
794 | * allowed as upper are limited to "normal" ones, where checking | |
795 | * for the above two errors is sufficient. | |
796 | */ | |
c7c7a1a1 TA |
797 | err = vfs_removexattr(&init_user_ns, work, |
798 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
e1ff3dd1 | 799 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
800 | goto out_dput; |
801 | ||
c7c7a1a1 TA |
802 | err = vfs_removexattr(&init_user_ns, work, |
803 | XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 804 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
805 | goto out_dput; |
806 | ||
807 | /* Clear any inherited mode bits */ | |
808 | inode_lock(work->d_inode); | |
2f221d6f | 809 | err = notify_change(&init_user_ns, work, &attr, NULL); |
c11b9fdd MS |
810 | inode_unlock(work->d_inode); |
811 | if (err) | |
812 | goto out_dput; | |
6b8aa129 AG |
813 | } else { |
814 | err = PTR_ERR(work); | |
815 | goto out_err; | |
e9be9d5e MS |
816 | } |
817 | out_unlock: | |
2068cf7d | 818 | inode_unlock(dir); |
e9be9d5e MS |
819 | return work; |
820 | ||
821 | out_dput: | |
822 | dput(work); | |
6b8aa129 | 823 | out_err: |
1bd0a3ae | 824 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 825 | ofs->config.workdir, name, -err); |
6b8aa129 | 826 | work = NULL; |
e9be9d5e MS |
827 | goto out_unlock; |
828 | } | |
829 | ||
91c77947 MS |
830 | static void ovl_unescape(char *s) |
831 | { | |
832 | char *d = s; | |
833 | ||
834 | for (;; s++, d++) { | |
835 | if (*s == '\\') | |
836 | s++; | |
837 | *d = *s; | |
838 | if (!*s) | |
839 | break; | |
840 | } | |
841 | } | |
842 | ||
ab508822 MS |
843 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
844 | { | |
a78d9f0d | 845 | int err = -EINVAL; |
ab508822 | 846 | |
a78d9f0d | 847 | if (!*name) { |
1bd0a3ae | 848 | pr_err("empty lowerdir\n"); |
a78d9f0d MS |
849 | goto out; |
850 | } | |
ab508822 MS |
851 | err = kern_path(name, LOOKUP_FOLLOW, path); |
852 | if (err) { | |
1bd0a3ae | 853 | pr_err("failed to resolve '%s': %i\n", name, err); |
ab508822 MS |
854 | goto out; |
855 | } | |
856 | err = -EINVAL; | |
7c03b5d4 | 857 | if (ovl_dentry_weird(path->dentry)) { |
1bd0a3ae | 858 | pr_err("filesystem on '%s' not supported\n", name); |
ab508822 MS |
859 | goto out_put; |
860 | } | |
2b8c30e9 | 861 | if (!d_is_dir(path->dentry)) { |
1bd0a3ae | 862 | pr_err("'%s' not a directory\n", name); |
ab508822 MS |
863 | goto out_put; |
864 | } | |
865 | return 0; | |
866 | ||
867 | out_put: | |
8aafcb59 | 868 | path_put_init(path); |
ab508822 MS |
869 | out: |
870 | return err; | |
871 | } | |
872 | ||
873 | static int ovl_mount_dir(const char *name, struct path *path) | |
874 | { | |
875 | int err = -ENOMEM; | |
876 | char *tmp = kstrdup(name, GFP_KERNEL); | |
877 | ||
878 | if (tmp) { | |
879 | ovl_unescape(tmp); | |
880 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 | 881 | |
bccece1e | 882 | if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { |
7925dad8 MS |
883 | pr_err("filesystem on '%s' not supported as upperdir\n", |
884 | tmp); | |
885 | path_put_init(path); | |
886 | err = -EINVAL; | |
887 | } | |
ab508822 MS |
888 | kfree(tmp); |
889 | } | |
890 | return err; | |
891 | } | |
892 | ||
6b2d5fe4 MS |
893 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
894 | const char *name) | |
ab508822 | 895 | { |
ab508822 | 896 | struct kstatfs statfs; |
6b2d5fe4 MS |
897 | int err = vfs_statfs(path, &statfs); |
898 | ||
899 | if (err) | |
1bd0a3ae | 900 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
901 | else |
902 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
903 | ||
904 | return err; | |
905 | } | |
906 | ||
907 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 908 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 909 | { |
e487d889 | 910 | int fh_type; |
6b2d5fe4 | 911 | int err; |
ab508822 | 912 | |
a78d9f0d | 913 | err = ovl_mount_dir_noesc(name, path); |
ab508822 | 914 | if (err) |
b8e42a65 | 915 | return err; |
ab508822 | 916 | |
6b2d5fe4 MS |
917 | err = ovl_check_namelen(path, ofs, name); |
918 | if (err) | |
b8e42a65 | 919 | return err; |
6b2d5fe4 | 920 | |
ab508822 MS |
921 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
922 | ||
02bcd157 | 923 | /* |
f168f109 AG |
924 | * The inodes index feature and NFS export need to encode and decode |
925 | * file handles, so they require that all layers support them. | |
02bcd157 | 926 | */ |
e487d889 | 927 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 928 | if ((ofs->config.nfs_export || |
e487d889 | 929 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 930 | ofs->config.index = false; |
f168f109 | 931 | ofs->config.nfs_export = false; |
1bd0a3ae | 932 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 933 | name); |
02bcd157 AG |
934 | } |
935 | ||
e487d889 AG |
936 | /* Check if lower fs has 32bit inode numbers */ |
937 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 938 | ofs->xino_mode = -1; |
e487d889 | 939 | |
ab508822 | 940 | return 0; |
ab508822 MS |
941 | } |
942 | ||
e9be9d5e MS |
943 | /* Workdir should not be subdir of upperdir and vice versa */ |
944 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
945 | { | |
946 | bool ok = false; | |
947 | ||
948 | if (workdir != upperdir) { | |
949 | ok = (lock_rename(workdir, upperdir) == NULL); | |
950 | unlock_rename(workdir, upperdir); | |
951 | } | |
952 | return ok; | |
953 | } | |
954 | ||
a78d9f0d MS |
955 | static unsigned int ovl_split_lowerdirs(char *str) |
956 | { | |
957 | unsigned int ctr = 1; | |
958 | char *s, *d; | |
959 | ||
960 | for (s = d = str;; s++, d++) { | |
961 | if (*s == '\\') { | |
962 | s++; | |
963 | } else if (*s == ':') { | |
964 | *d = '\0'; | |
965 | ctr++; | |
966 | continue; | |
967 | } | |
968 | *d = *s; | |
969 | if (!*s) | |
970 | break; | |
971 | } | |
972 | return ctr; | |
973 | } | |
974 | ||
0eb45fc3 AG |
975 | static int __maybe_unused |
976 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
977 | struct dentry *dentry, struct inode *inode, | |
978 | const char *name, void *buffer, size_t size) | |
979 | { | |
1d88f183 | 980 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
0eb45fc3 AG |
981 | } |
982 | ||
0c97be22 AG |
983 | static int __maybe_unused |
984 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 | 985 | struct user_namespace *mnt_userns, |
0c97be22 AG |
986 | struct dentry *dentry, struct inode *inode, |
987 | const char *name, const void *value, | |
988 | size_t size, int flags) | |
d837a49b MS |
989 | { |
990 | struct dentry *workdir = ovl_workdir(dentry); | |
09d8b586 | 991 | struct inode *realinode = ovl_inode_real(inode); |
d837a49b MS |
992 | struct posix_acl *acl = NULL; |
993 | int err; | |
994 | ||
995 | /* Check that everything is OK before copy-up */ | |
996 | if (value) { | |
997 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
998 | if (IS_ERR(acl)) | |
999 | return PTR_ERR(acl); | |
1000 | } | |
1001 | err = -EOPNOTSUPP; | |
1002 | if (!IS_POSIXACL(d_inode(workdir))) | |
1003 | goto out_acl_release; | |
1004 | if (!realinode->i_op->set_acl) | |
1005 | goto out_acl_release; | |
1006 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
1007 | err = acl ? -EACCES : 0; | |
1008 | goto out_acl_release; | |
1009 | } | |
1010 | err = -EPERM; | |
21cb47be | 1011 | if (!inode_owner_or_capable(&init_user_ns, inode)) |
d837a49b MS |
1012 | goto out_acl_release; |
1013 | ||
1014 | posix_acl_release(acl); | |
1015 | ||
fd3220d3 MS |
1016 | /* |
1017 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
1018 | * be done with mounter's capabilities and so that won't do it for us). | |
1019 | */ | |
1020 | if (unlikely(inode->i_mode & S_ISGID) && | |
1021 | handler->flags == ACL_TYPE_ACCESS && | |
1022 | !in_group_p(inode->i_gid) && | |
0558c1bf | 1023 | !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) { |
fd3220d3 MS |
1024 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; |
1025 | ||
549c7297 | 1026 | err = ovl_setattr(&init_user_ns, dentry, &iattr); |
fd3220d3 MS |
1027 | if (err) |
1028 | return err; | |
1029 | } | |
1030 | ||
1d88f183 | 1031 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
ce31513a | 1032 | if (!err) |
09d8b586 | 1033 | ovl_copyattr(ovl_inode_real(inode), inode); |
ce31513a MS |
1034 | |
1035 | return err; | |
d837a49b MS |
1036 | |
1037 | out_acl_release: | |
1038 | posix_acl_release(acl); | |
1039 | return err; | |
1040 | } | |
1041 | ||
0eb45fc3 AG |
1042 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
1043 | struct dentry *dentry, struct inode *inode, | |
1044 | const char *name, void *buffer, size_t size) | |
1045 | { | |
48fab5d7 | 1046 | return -EOPNOTSUPP; |
0eb45fc3 AG |
1047 | } |
1048 | ||
d837a49b | 1049 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
e65ce2a5 | 1050 | struct user_namespace *mnt_userns, |
d837a49b MS |
1051 | struct dentry *dentry, struct inode *inode, |
1052 | const char *name, const void *value, | |
1053 | size_t size, int flags) | |
1054 | { | |
48fab5d7 | 1055 | return -EOPNOTSUPP; |
d837a49b MS |
1056 | } |
1057 | ||
0eb45fc3 AG |
1058 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
1059 | struct dentry *dentry, struct inode *inode, | |
1060 | const char *name, void *buffer, size_t size) | |
1061 | { | |
1d88f183 | 1062 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
1063 | } |
1064 | ||
0e585ccc | 1065 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
e65ce2a5 | 1066 | struct user_namespace *mnt_userns, |
0e585ccc AG |
1067 | struct dentry *dentry, struct inode *inode, |
1068 | const char *name, const void *value, | |
1069 | size_t size, int flags) | |
1070 | { | |
1d88f183 | 1071 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
1072 | } |
1073 | ||
0c97be22 AG |
1074 | static const struct xattr_handler __maybe_unused |
1075 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
1076 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
1077 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 1078 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
1079 | .set = ovl_posix_acl_xattr_set, |
1080 | }; | |
1081 | ||
0c97be22 AG |
1082 | static const struct xattr_handler __maybe_unused |
1083 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
1084 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
1085 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 1086 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
1087 | .set = ovl_posix_acl_xattr_set, |
1088 | }; | |
1089 | ||
2d2f2d73 MS |
1090 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
1091 | .prefix = OVL_XATTR_TRUSTED_PREFIX, | |
1092 | .get = ovl_own_xattr_get, | |
1093 | .set = ovl_own_xattr_set, | |
1094 | }; | |
1095 | ||
1096 | static const struct xattr_handler ovl_own_user_xattr_handler = { | |
1097 | .prefix = OVL_XATTR_USER_PREFIX, | |
0eb45fc3 | 1098 | .get = ovl_own_xattr_get, |
d837a49b MS |
1099 | .set = ovl_own_xattr_set, |
1100 | }; | |
1101 | ||
1102 | static const struct xattr_handler ovl_other_xattr_handler = { | |
1103 | .prefix = "", /* catch all */ | |
0eb45fc3 | 1104 | .get = ovl_other_xattr_get, |
d837a49b MS |
1105 | .set = ovl_other_xattr_set, |
1106 | }; | |
1107 | ||
2d2f2d73 MS |
1108 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
1109 | #ifdef CONFIG_FS_POSIX_ACL | |
1110 | &ovl_posix_acl_access_xattr_handler, | |
1111 | &ovl_posix_acl_default_xattr_handler, | |
1112 | #endif | |
1113 | &ovl_own_trusted_xattr_handler, | |
1114 | &ovl_other_xattr_handler, | |
1115 | NULL | |
1116 | }; | |
1117 | ||
1118 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { | |
0c97be22 | 1119 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
1120 | &ovl_posix_acl_access_xattr_handler, |
1121 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 1122 | #endif |
2d2f2d73 | 1123 | &ovl_own_user_xattr_handler, |
d837a49b MS |
1124 | &ovl_other_xattr_handler, |
1125 | NULL | |
1126 | }; | |
1127 | ||
146d62e5 AG |
1128 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
1129 | struct inode **ptrap, const char *name) | |
1130 | { | |
1131 | struct inode *trap; | |
1132 | int err; | |
1133 | ||
1134 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
1135 | err = PTR_ERR_OR_ZERO(trap); |
1136 | if (err) { | |
146d62e5 | 1137 | if (err == -ELOOP) |
1bd0a3ae | 1138 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
1139 | return err; |
1140 | } | |
1141 | ||
1142 | *ptrap = trap; | |
1143 | return 0; | |
1144 | } | |
1145 | ||
0be0bfd2 AG |
1146 | /* |
1147 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
1148 | * index feature. This is papering over mount leaks of container runtimes, | |
1149 | * for example, an old overlay mount is leaked and now its upperdir is | |
1150 | * attempted to be used as a lower layer in a new overlay mount. | |
1151 | */ | |
1152 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
1153 | { | |
1154 | if (ofs->config.index) { | |
1bd0a3ae | 1155 | pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", |
0be0bfd2 AG |
1156 | name); |
1157 | return -EBUSY; | |
1158 | } else { | |
1bd0a3ae | 1159 | pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", |
0be0bfd2 AG |
1160 | name); |
1161 | return 0; | |
1162 | } | |
1163 | } | |
1164 | ||
146d62e5 | 1165 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 | 1166 | struct ovl_layer *upper_layer, struct path *upperpath) |
6ee8acf0 | 1167 | { |
5064975e | 1168 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
1169 | int err; |
1170 | ||
ad204488 | 1171 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
6ee8acf0 MS |
1172 | if (err) |
1173 | goto out; | |
1174 | ||
1175 | /* Upper fs should not be r/o */ | |
1176 | if (sb_rdonly(upperpath->mnt->mnt_sb)) { | |
1bd0a3ae | 1177 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
1178 | err = -EINVAL; |
1179 | goto out; | |
1180 | } | |
1181 | ||
ad204488 | 1182 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
1183 | if (err) |
1184 | goto out; | |
1185 | ||
b8e42a65 | 1186 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
1187 | "upperdir"); |
1188 | if (err) | |
1189 | goto out; | |
1190 | ||
5064975e MS |
1191 | upper_mnt = clone_private_mount(upperpath); |
1192 | err = PTR_ERR(upper_mnt); | |
1193 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 1194 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
1195 | goto out; |
1196 | } | |
1197 | ||
1198 | /* Don't inherit atime flags */ | |
1199 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
1200 | upper_layer->mnt = upper_mnt; |
1201 | upper_layer->idx = 0; | |
1202 | upper_layer->fsid = 0; | |
8c25741a | 1203 | |
654255fa JX |
1204 | /* |
1205 | * Inherit SB_NOSEC flag from upperdir. | |
1206 | * | |
1207 | * This optimization changes behavior when a security related attribute | |
1208 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
1209 | * okay because we don't yet have guarantees in that case, but it will | |
1210 | * need careful treatment once we want to honour changes to underlying | |
1211 | * filesystems. | |
1212 | */ | |
1213 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
1214 | sb->s_flags |= SB_NOSEC; | |
1215 | ||
08f4c7c8 | 1216 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 1217 | ofs->upperdir_locked = true; |
8c25741a | 1218 | } else { |
0be0bfd2 AG |
1219 | err = ovl_report_in_use(ofs, "upperdir"); |
1220 | if (err) | |
1221 | goto out; | |
8c25741a MS |
1222 | } |
1223 | ||
6ee8acf0 MS |
1224 | err = 0; |
1225 | out: | |
1226 | return err; | |
1227 | } | |
1228 | ||
cad218ab AG |
1229 | /* |
1230 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
1231 | * negative values if error is encountered. | |
1232 | */ | |
1233 | static int ovl_check_rename_whiteout(struct dentry *workdir) | |
1234 | { | |
1235 | struct inode *dir = d_inode(workdir); | |
1236 | struct dentry *temp; | |
1237 | struct dentry *dest; | |
1238 | struct dentry *whiteout; | |
1239 | struct name_snapshot name; | |
1240 | int err; | |
1241 | ||
1242 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
1243 | ||
1244 | temp = ovl_create_temp(workdir, OVL_CATTR(S_IFREG | 0)); | |
1245 | err = PTR_ERR(temp); | |
1246 | if (IS_ERR(temp)) | |
1247 | goto out_unlock; | |
1248 | ||
1249 | dest = ovl_lookup_temp(workdir); | |
1250 | err = PTR_ERR(dest); | |
1251 | if (IS_ERR(dest)) { | |
1252 | dput(temp); | |
1253 | goto out_unlock; | |
1254 | } | |
1255 | ||
1256 | /* Name is inline and stable - using snapshot as a copy helper */ | |
1257 | take_dentry_name_snapshot(&name, temp); | |
1258 | err = ovl_do_rename(dir, temp, dir, dest, RENAME_WHITEOUT); | |
1259 | if (err) { | |
1260 | if (err == -EINVAL) | |
1261 | err = 0; | |
1262 | goto cleanup_temp; | |
1263 | } | |
1264 | ||
1265 | whiteout = lookup_one_len(name.name.name, workdir, name.name.len); | |
1266 | err = PTR_ERR(whiteout); | |
1267 | if (IS_ERR(whiteout)) | |
1268 | goto cleanup_temp; | |
1269 | ||
1270 | err = ovl_is_whiteout(whiteout); | |
1271 | ||
1272 | /* Best effort cleanup of whiteout and temp file */ | |
1273 | if (err) | |
1274 | ovl_cleanup(dir, whiteout); | |
1275 | dput(whiteout); | |
1276 | ||
1277 | cleanup_temp: | |
1278 | ovl_cleanup(dir, temp); | |
1279 | release_dentry_name_snapshot(&name); | |
1280 | dput(temp); | |
1281 | dput(dest); | |
1282 | ||
1283 | out_unlock: | |
1284 | inode_unlock(dir); | |
1285 | ||
1286 | return err; | |
1287 | } | |
1288 | ||
c86243b0 VG |
1289 | static struct dentry *ovl_lookup_or_create(struct dentry *parent, |
1290 | const char *name, umode_t mode) | |
1291 | { | |
1292 | size_t len = strlen(name); | |
1293 | struct dentry *child; | |
1294 | ||
1295 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
1296 | child = lookup_one_len(name, parent, len); | |
1297 | if (!IS_ERR(child) && !child->d_inode) | |
1298 | child = ovl_create_real(parent->d_inode, child, | |
1299 | OVL_CATTR(mode)); | |
1300 | inode_unlock(parent->d_inode); | |
1301 | dput(parent); | |
1302 | ||
1303 | return child; | |
1304 | } | |
1305 | ||
1306 | /* | |
1307 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
1308 | * present. | |
1309 | */ | |
1310 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
1311 | { | |
1312 | unsigned int ctr; | |
1313 | struct dentry *d = dget(ofs->workbasedir); | |
1314 | static const char *const volatile_path[] = { | |
1315 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
1316 | }; | |
1317 | const char *const *name = volatile_path; | |
1318 | ||
1319 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
1320 | d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG); | |
1321 | if (IS_ERR(d)) | |
1322 | return PTR_ERR(d); | |
1323 | } | |
1324 | dput(d); | |
1325 | return 0; | |
1326 | } | |
1327 | ||
146d62e5 AG |
1328 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
1329 | struct path *workpath) | |
8ed61dc3 | 1330 | { |
08f4c7c8 | 1331 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 1332 | struct dentry *temp, *workdir; |
d80172c2 AG |
1333 | bool rename_whiteout; |
1334 | bool d_type; | |
e487d889 | 1335 | int fh_type; |
8ed61dc3 MS |
1336 | int err; |
1337 | ||
2ba9d57e AG |
1338 | err = mnt_want_write(mnt); |
1339 | if (err) | |
1340 | return err; | |
1341 | ||
235ce9ed AG |
1342 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
1343 | err = PTR_ERR(workdir); | |
1344 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 1345 | goto out; |
8ed61dc3 | 1346 | |
235ce9ed AG |
1347 | ofs->workdir = workdir; |
1348 | ||
146d62e5 AG |
1349 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
1350 | if (err) | |
1351 | goto out; | |
1352 | ||
8ed61dc3 MS |
1353 | /* |
1354 | * Upper should support d_type, else whiteouts are visible. Given | |
1355 | * workdir and upper are on same fs, we can do iterate_dir() on | |
1356 | * workdir. This check requires successful creation of workdir in | |
1357 | * previous step. | |
1358 | */ | |
1359 | err = ovl_check_d_type_supported(workpath); | |
1360 | if (err < 0) | |
2ba9d57e | 1361 | goto out; |
8ed61dc3 | 1362 | |
d80172c2 AG |
1363 | d_type = err; |
1364 | if (!d_type) | |
1bd0a3ae | 1365 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
1366 | |
1367 | /* Check if upper/work fs supports O_TMPFILE */ | |
ad204488 MS |
1368 | temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); |
1369 | ofs->tmpfile = !IS_ERR(temp); | |
1370 | if (ofs->tmpfile) | |
8ed61dc3 MS |
1371 | dput(temp); |
1372 | else | |
1bd0a3ae | 1373 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 1374 | |
cad218ab AG |
1375 | |
1376 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
1377 | err = ovl_check_rename_whiteout(ofs->workdir); | |
1378 | if (err < 0) | |
1379 | goto out; | |
1380 | ||
d80172c2 AG |
1381 | rename_whiteout = err; |
1382 | if (!rename_whiteout) | |
cad218ab AG |
1383 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
1384 | ||
8ed61dc3 | 1385 | /* |
2d2f2d73 | 1386 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 1387 | */ |
610afc0b | 1388 | err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 1389 | if (err) { |
ad204488 | 1390 | ofs->noxattr = true; |
a683737b | 1391 | ofs->config.index = false; |
d5791044 | 1392 | ofs->config.metacopy = false; |
1bd0a3ae | 1393 | pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n"); |
2ba9d57e | 1394 | err = 0; |
8ed61dc3 | 1395 | } else { |
610afc0b | 1396 | ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
1397 | } |
1398 | ||
d80172c2 AG |
1399 | /* |
1400 | * We allowed sub-optimal upper fs configuration and don't want to break | |
1401 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
1402 | * we can enforce strict requirements for remote upper fs. | |
1403 | */ | |
1404 | if (ovl_dentry_remote(ofs->workdir) && | |
1405 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
1406 | pr_err("upper fs missing required features.\n"); | |
1407 | err = -EINVAL; | |
1408 | goto out; | |
1409 | } | |
1410 | ||
c86243b0 VG |
1411 | /* |
1412 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
1413 | * track of it. | |
1414 | */ | |
1415 | if (ofs->config.ovl_volatile) { | |
1416 | err = ovl_create_volatile_dirty(ofs); | |
1417 | if (err < 0) { | |
1418 | pr_err("Failed to create volatile/dirty file.\n"); | |
1419 | goto out; | |
1420 | } | |
1421 | } | |
1422 | ||
8ed61dc3 | 1423 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
1424 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
1425 | if (ofs->config.index && !fh_type) { | |
ad204488 | 1426 | ofs->config.index = false; |
1bd0a3ae | 1427 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 MS |
1428 | } |
1429 | ||
e487d889 AG |
1430 | /* Check if upper fs has 32bit inode numbers */ |
1431 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 1432 | ofs->xino_mode = -1; |
e487d889 | 1433 | |
f168f109 AG |
1434 | /* NFS export of r/w mount depends on index */ |
1435 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 1436 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
1437 | ofs->config.nfs_export = false; |
1438 | } | |
2ba9d57e AG |
1439 | out: |
1440 | mnt_drop_write(mnt); | |
1441 | return err; | |
8ed61dc3 MS |
1442 | } |
1443 | ||
146d62e5 AG |
1444 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
1445 | struct path *upperpath) | |
520d7c86 MS |
1446 | { |
1447 | int err; | |
bca44b52 | 1448 | struct path workpath = { }; |
520d7c86 | 1449 | |
ad204488 | 1450 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
520d7c86 MS |
1451 | if (err) |
1452 | goto out; | |
1453 | ||
1454 | err = -EINVAL; | |
bca44b52 | 1455 | if (upperpath->mnt != workpath.mnt) { |
1bd0a3ae | 1456 | pr_err("workdir and upperdir must reside under the same mount\n"); |
520d7c86 MS |
1457 | goto out; |
1458 | } | |
bca44b52 | 1459 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
1bd0a3ae | 1460 | pr_err("workdir and upperdir must be separate subtrees\n"); |
520d7c86 MS |
1461 | goto out; |
1462 | } | |
1463 | ||
8c25741a MS |
1464 | ofs->workbasedir = dget(workpath.dentry); |
1465 | ||
8c25741a | 1466 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 1467 | ofs->workdir_locked = true; |
520d7c86 | 1468 | } else { |
0be0bfd2 AG |
1469 | err = ovl_report_in_use(ofs, "workdir"); |
1470 | if (err) | |
1471 | goto out; | |
520d7c86 MS |
1472 | } |
1473 | ||
0be0bfd2 AG |
1474 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
1475 | "workdir"); | |
1476 | if (err) | |
1477 | goto out; | |
1478 | ||
146d62e5 | 1479 | err = ovl_make_workdir(sb, ofs, &workpath); |
bca44b52 | 1480 | |
520d7c86 | 1481 | out: |
bca44b52 MS |
1482 | path_put(&workpath); |
1483 | ||
520d7c86 MS |
1484 | return err; |
1485 | } | |
1486 | ||
146d62e5 AG |
1487 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
1488 | struct ovl_entry *oe, struct path *upperpath) | |
f7e3a7d9 | 1489 | { |
08f4c7c8 | 1490 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 1491 | struct dentry *indexdir; |
f7e3a7d9 MS |
1492 | int err; |
1493 | ||
2ba9d57e AG |
1494 | err = mnt_want_write(mnt); |
1495 | if (err) | |
1496 | return err; | |
1497 | ||
f7e3a7d9 | 1498 | /* Verify lower root is upper root origin */ |
610afc0b MS |
1499 | err = ovl_verify_origin(ofs, upperpath->dentry, |
1500 | oe->lowerstack[0].dentry, true); | |
f7e3a7d9 | 1501 | if (err) { |
1bd0a3ae | 1502 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
1503 | goto out; |
1504 | } | |
1505 | ||
470c1563 AG |
1506 | /* index dir will act also as workdir */ |
1507 | iput(ofs->workdir_trap); | |
1508 | ofs->workdir_trap = NULL; | |
1509 | dput(ofs->workdir); | |
1510 | ofs->workdir = NULL; | |
235ce9ed AG |
1511 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
1512 | if (IS_ERR(indexdir)) { | |
1513 | err = PTR_ERR(indexdir); | |
1514 | } else if (indexdir) { | |
1515 | ofs->indexdir = indexdir; | |
1516 | ofs->workdir = dget(indexdir); | |
20396365 | 1517 | |
146d62e5 AG |
1518 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
1519 | "indexdir"); | |
1520 | if (err) | |
1521 | goto out; | |
1522 | ||
ad1d615c AG |
1523 | /* |
1524 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 1525 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
1526 | * xattr. If that xattr exists, verify that it is a match to |
1527 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 1528 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
1529 | * directory entries. |
1530 | */ | |
610afc0b MS |
1531 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
1532 | err = ovl_verify_set_fh(ofs, ofs->indexdir, | |
1533 | OVL_XATTR_ORIGIN, | |
ad1d615c AG |
1534 | upperpath->dentry, true, false); |
1535 | if (err) | |
1bd0a3ae | 1536 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 1537 | } |
610afc0b MS |
1538 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
1539 | true); | |
f7e3a7d9 | 1540 | if (err) |
1bd0a3ae | 1541 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
1542 | |
1543 | /* Cleanup bad/stale/orphan index entries */ | |
1544 | if (!err) | |
1eff1a1d | 1545 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 1546 | } |
ad204488 | 1547 | if (err || !ofs->indexdir) |
1bd0a3ae | 1548 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
1549 | |
1550 | out: | |
2ba9d57e | 1551 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
1552 | return err; |
1553 | } | |
1554 | ||
9df085f3 AG |
1555 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
1556 | { | |
1557 | unsigned int i; | |
1558 | ||
08f4c7c8 | 1559 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
1560 | return true; |
1561 | ||
a888db31 AG |
1562 | /* |
1563 | * We allow using single lower with null uuid for index and nfs_export | |
1564 | * for example to support those features with single lower squashfs. | |
1565 | * To avoid regressions in setups of overlay with re-formatted lower | |
1566 | * squashfs, do not allow decoding origin with lower null uuid unless | |
1567 | * user opted-in to one of the new features that require following the | |
1568 | * lower inode of non-dir upper. | |
1569 | */ | |
1570 | if (!ofs->config.index && !ofs->config.metacopy && !ofs->config.xino && | |
1571 | uuid_is_null(uuid)) | |
1572 | return false; | |
1573 | ||
1b81dddd | 1574 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
1575 | /* |
1576 | * We use uuid to associate an overlay lower file handle with a | |
1577 | * lower layer, so we can accept lower fs with null uuid as long | |
1578 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
1579 | * if we detect multiple lower fs with the same uuid, we |
1580 | * disable lower file handle decoding on all of them. | |
9df085f3 | 1581 | */ |
1b81dddd AG |
1582 | if (ofs->fs[i].is_lower && |
1583 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 1584 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 1585 | return false; |
7e63c87f | 1586 | } |
9df085f3 AG |
1587 | } |
1588 | return true; | |
1589 | } | |
1590 | ||
5148626b | 1591 | /* Get a unique fsid for the layer */ |
9df085f3 | 1592 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 1593 | { |
9df085f3 | 1594 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
1595 | unsigned int i; |
1596 | dev_t dev; | |
1597 | int err; | |
7e63c87f | 1598 | bool bad_uuid = false; |
5148626b | 1599 | |
07f1e596 AG |
1600 | for (i = 0; i < ofs->numfs; i++) { |
1601 | if (ofs->fs[i].sb == sb) | |
1602 | return i; | |
5148626b AG |
1603 | } |
1604 | ||
9df085f3 | 1605 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f AG |
1606 | bad_uuid = true; |
1607 | if (ofs->config.index || ofs->config.nfs_export) { | |
1608 | ofs->config.index = false; | |
1609 | ofs->config.nfs_export = false; | |
1bd0a3ae | 1610 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n", |
7e63c87f AG |
1611 | uuid_is_null(&sb->s_uuid) ? "null" : |
1612 | "conflicting", | |
1613 | path->dentry); | |
1614 | } | |
9df085f3 AG |
1615 | } |
1616 | ||
5148626b AG |
1617 | err = get_anon_bdev(&dev); |
1618 | if (err) { | |
1bd0a3ae | 1619 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
1620 | return err; |
1621 | } | |
1622 | ||
07f1e596 AG |
1623 | ofs->fs[ofs->numfs].sb = sb; |
1624 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
1625 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 1626 | |
07f1e596 | 1627 | return ofs->numfs++; |
5148626b AG |
1628 | } |
1629 | ||
94375f9d | 1630 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 MS |
1631 | struct path *stack, unsigned int numlower, |
1632 | struct ovl_layer *layers) | |
520d7c86 MS |
1633 | { |
1634 | int err; | |
1635 | unsigned int i; | |
1636 | ||
1637 | err = -ENOMEM; | |
07f1e596 AG |
1638 | ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); |
1639 | if (ofs->fs == NULL) | |
5148626b AG |
1640 | goto out; |
1641 | ||
07f1e596 AG |
1642 | /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ |
1643 | ofs->numfs++; | |
1644 | ||
07f1e596 | 1645 | /* |
b7bf9908 AG |
1646 | * All lower layers that share the same fs as upper layer, use the same |
1647 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1648 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1649 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1650 | */ |
b7bf9908 AG |
1651 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1652 | if (err) { | |
1653 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
1654 | goto out; | |
1655 | } | |
1656 | ||
08f4c7c8 MS |
1657 | if (ovl_upper_mnt(ofs)) { |
1658 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1659 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1660 | } |
1661 | ||
520d7c86 MS |
1662 | for (i = 0; i < numlower; i++) { |
1663 | struct vfsmount *mnt; | |
146d62e5 | 1664 | struct inode *trap; |
5148626b | 1665 | int fsid; |
520d7c86 | 1666 | |
9df085f3 | 1667 | err = fsid = ovl_get_fsid(ofs, &stack[i]); |
5148626b | 1668 | if (err < 0) |
520d7c86 | 1669 | goto out; |
520d7c86 | 1670 | |
24f14009 | 1671 | /* |
1672 | * Check if lower root conflicts with this overlay layers before | |
1673 | * checking if it is in-use as upperdir/workdir of "another" | |
1674 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1675 | * the upperdir/workdir is in fact in-use by our | |
1676 | * upperdir/workdir. | |
1677 | */ | |
146d62e5 AG |
1678 | err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); |
1679 | if (err) | |
1680 | goto out; | |
1681 | ||
0be0bfd2 AG |
1682 | if (ovl_is_inuse(stack[i].dentry)) { |
1683 | err = ovl_report_in_use(ofs, "lowerdir"); | |
24f14009 | 1684 | if (err) { |
1685 | iput(trap); | |
0be0bfd2 | 1686 | goto out; |
24f14009 | 1687 | } |
0be0bfd2 AG |
1688 | } |
1689 | ||
520d7c86 MS |
1690 | mnt = clone_private_mount(&stack[i]); |
1691 | err = PTR_ERR(mnt); | |
1692 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1693 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1694 | iput(trap); |
520d7c86 MS |
1695 | goto out; |
1696 | } | |
5148626b | 1697 | |
520d7c86 MS |
1698 | /* |
1699 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1700 | * will fail instead of modifying lower fs. | |
1701 | */ | |
1702 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1703 | ||
13464165 MS |
1704 | layers[ofs->numlayer].trap = trap; |
1705 | layers[ofs->numlayer].mnt = mnt; | |
1706 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1707 | layers[ofs->numlayer].fsid = fsid; | |
1708 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
94375f9d | 1709 | ofs->numlayer++; |
1b81dddd | 1710 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1711 | } |
e487d889 | 1712 | |
795939a9 AG |
1713 | /* |
1714 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1715 | * With mount option "xino=<on|auto>", mounter declares that there are |
1716 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1717 | * If overlayfs does encounter underlying inodes using the high xino |
1718 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1719 | * inode number or a non persistent inode number allocated from a |
1720 | * dedicated range. | |
795939a9 | 1721 | */ |
08f4c7c8 | 1722 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1723 | if (ofs->config.xino == OVL_XINO_ON) |
1724 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1725 | ofs->xino_mode = 0; | |
53afcd31 AG |
1726 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1727 | ofs->xino_mode = -1; | |
926e94d7 | 1728 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1729 | /* |
07f1e596 | 1730 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1731 | * fsid, where fsid 0 is reserved for upper fs (even with |
1732 | * lower only overlay) +1 extra bit is reserved for the non | |
1733 | * persistent inode number range that is used for resolving | |
1734 | * xino lower bits overflow. | |
795939a9 | 1735 | */ |
dfe51d47 AG |
1736 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1737 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1738 | } |
1739 | ||
0f831ec8 | 1740 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1741 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1742 | ofs->xino_mode); |
795939a9 | 1743 | } |
e487d889 | 1744 | |
520d7c86 MS |
1745 | err = 0; |
1746 | out: | |
1747 | return err; | |
1748 | } | |
1749 | ||
4155c10a | 1750 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b8e42a65 MS |
1751 | const char *lower, unsigned int numlower, |
1752 | struct ovl_fs *ofs, struct ovl_layer *layers) | |
53dbb0b4 MS |
1753 | { |
1754 | int err; | |
4155c10a | 1755 | struct path *stack = NULL; |
b8e42a65 | 1756 | unsigned int i; |
4155c10a | 1757 | struct ovl_entry *oe; |
53dbb0b4 | 1758 | |
b8e42a65 | 1759 | if (!ofs->config.upperdir && numlower == 1) { |
1bd0a3ae | 1760 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1761 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1762 | } |
1763 | ||
b8e42a65 | 1764 | stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); |
53dbb0b4 | 1765 | if (!stack) |
b8e42a65 | 1766 | return ERR_PTR(-ENOMEM); |
53dbb0b4 MS |
1767 | |
1768 | err = -EINVAL; | |
b8e42a65 MS |
1769 | for (i = 0; i < numlower; i++) { |
1770 | err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); | |
53dbb0b4 | 1771 | if (err) |
4155c10a | 1772 | goto out_err; |
53dbb0b4 MS |
1773 | |
1774 | lower = strchr(lower, '\0') + 1; | |
1775 | } | |
1776 | ||
1777 | err = -EINVAL; | |
1778 | sb->s_stack_depth++; | |
1779 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1780 | pr_err("maximum fs stacking depth exceeded\n"); |
4155c10a | 1781 | goto out_err; |
53dbb0b4 MS |
1782 | } |
1783 | ||
b8e42a65 | 1784 | err = ovl_get_layers(sb, ofs, stack, numlower, layers); |
4155c10a MS |
1785 | if (err) |
1786 | goto out_err; | |
1787 | ||
1788 | err = -ENOMEM; | |
1789 | oe = ovl_alloc_entry(numlower); | |
1790 | if (!oe) | |
1791 | goto out_err; | |
1792 | ||
1793 | for (i = 0; i < numlower; i++) { | |
1794 | oe->lowerstack[i].dentry = dget(stack[i].dentry); | |
94375f9d | 1795 | oe->lowerstack[i].layer = &ofs->layers[i+1]; |
4155c10a | 1796 | } |
53dbb0b4 | 1797 | |
53dbb0b4 | 1798 | out: |
53dbb0b4 MS |
1799 | for (i = 0; i < numlower; i++) |
1800 | path_put(&stack[i]); | |
1801 | kfree(stack); | |
4155c10a MS |
1802 | |
1803 | return oe; | |
1804 | ||
1805 | out_err: | |
1806 | oe = ERR_PTR(err); | |
53dbb0b4 MS |
1807 | goto out; |
1808 | } | |
1809 | ||
146d62e5 AG |
1810 | /* |
1811 | * Check if this layer root is a descendant of: | |
1812 | * - another layer of this overlayfs instance | |
1813 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1814 | */ |
0be0bfd2 AG |
1815 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
1816 | struct dentry *dentry, const char *name) | |
146d62e5 | 1817 | { |
9179c21d | 1818 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1819 | int err = 0; |
1820 | ||
9179c21d | 1821 | if (!dentry) |
146d62e5 AG |
1822 | return 0; |
1823 | ||
9179c21d MS |
1824 | parent = dget_parent(next); |
1825 | ||
1826 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1827 | while (!err && parent != next) { | |
0be0bfd2 | 1828 | if (ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1829 | err = -ELOOP; |
1bd0a3ae | 1830 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1831 | } else if (ovl_is_inuse(parent)) { |
1832 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1833 | } |
146d62e5 | 1834 | next = parent; |
9179c21d MS |
1835 | parent = dget_parent(next); |
1836 | dput(next); | |
146d62e5 AG |
1837 | } |
1838 | ||
9179c21d | 1839 | dput(parent); |
146d62e5 AG |
1840 | |
1841 | return err; | |
1842 | } | |
1843 | ||
1844 | /* | |
1845 | * Check if any of the layers or work dirs overlap. | |
1846 | */ | |
1847 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1848 | struct ovl_fs *ofs) | |
1849 | { | |
1850 | int i, err; | |
1851 | ||
08f4c7c8 MS |
1852 | if (ovl_upper_mnt(ofs)) { |
1853 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
0be0bfd2 | 1854 | "upperdir"); |
146d62e5 AG |
1855 | if (err) |
1856 | return err; | |
1857 | ||
1858 | /* | |
1859 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1860 | * this instance and covers overlapping work and index dirs, | |
1861 | * unless work or index dir have been moved since created inside | |
1862 | * workbasedir. In that case, we already have their traps in | |
1863 | * inode cache and we will catch that case on lookup. | |
1864 | */ | |
0be0bfd2 | 1865 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir"); |
146d62e5 AG |
1866 | if (err) |
1867 | return err; | |
1868 | } | |
1869 | ||
94375f9d | 1870 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1871 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1872 | ofs->layers[i].mnt->mnt_root, |
146d62e5 AG |
1873 | "lowerdir"); |
1874 | if (err) | |
1875 | return err; | |
1876 | } | |
1877 | ||
1878 | return 0; | |
1879 | } | |
1880 | ||
2effc5c2 AG |
1881 | static struct dentry *ovl_get_root(struct super_block *sb, |
1882 | struct dentry *upperdentry, | |
1883 | struct ovl_entry *oe) | |
1884 | { | |
1885 | struct dentry *root; | |
62c832ed AG |
1886 | struct ovl_path *lowerpath = &oe->lowerstack[0]; |
1887 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; | |
1888 | int fsid = lowerpath->layer->fsid; | |
1889 | struct ovl_inode_params oip = { | |
1890 | .upperdentry = upperdentry, | |
1891 | .lowerpath = lowerpath, | |
1892 | }; | |
2effc5c2 AG |
1893 | |
1894 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1895 | if (!root) | |
1896 | return NULL; | |
1897 | ||
1898 | root->d_fsdata = oe; | |
1899 | ||
1900 | if (upperdentry) { | |
62c832ed AG |
1901 | /* Root inode uses upper st_ino/i_ino */ |
1902 | ino = d_inode(upperdentry)->i_ino; | |
1903 | fsid = 0; | |
2effc5c2 | 1904 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1905 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1906 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1907 | } | |
1908 | ||
1909 | /* Root is always merge -> can have whiteouts */ | |
1910 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1911 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1912 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1913 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
f4288844 | 1914 | ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); |
2effc5c2 AG |
1915 | |
1916 | return root; | |
1917 | } | |
1918 | ||
e9be9d5e MS |
1919 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1920 | { | |
33006cdf | 1921 | struct path upperpath = { }; |
e9be9d5e | 1922 | struct dentry *root_dentry; |
4155c10a | 1923 | struct ovl_entry *oe; |
ad204488 | 1924 | struct ovl_fs *ofs; |
b8e42a65 | 1925 | struct ovl_layer *layers; |
51f8f3c4 | 1926 | struct cred *cred; |
b8e42a65 MS |
1927 | char *splitlower = NULL; |
1928 | unsigned int numlower; | |
e9be9d5e MS |
1929 | int err; |
1930 | ||
f4288844 MS |
1931 | sb->s_d_op = &ovl_dentry_operations; |
1932 | ||
f45827e8 | 1933 | err = -ENOMEM; |
ad204488 MS |
1934 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
1935 | if (!ofs) | |
e9be9d5e MS |
1936 | goto out; |
1937 | ||
ad204488 | 1938 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1939 | if (!cred) |
1940 | goto out_err; | |
1941 | ||
c21c839b CX |
1942 | /* Is there a reason anyone would want not to share whiteouts? */ |
1943 | ofs->share_whiteout = true; | |
1944 | ||
ad204488 | 1945 | ofs->config.index = ovl_index_def; |
5830fb6b | 1946 | ofs->config.uuid = true; |
f168f109 | 1947 | ofs->config.nfs_export = ovl_nfs_export_def; |
795939a9 | 1948 | ofs->config.xino = ovl_xino_def(); |
d5791044 | 1949 | ofs->config.metacopy = ovl_metacopy_def; |
ad204488 | 1950 | err = ovl_parse_opt((char *) data, &ofs->config); |
f45827e8 | 1951 | if (err) |
a9075cdb | 1952 | goto out_err; |
f45827e8 | 1953 | |
e9be9d5e | 1954 | err = -EINVAL; |
ad204488 | 1955 | if (!ofs->config.lowerdir) { |
07f2af7b | 1956 | if (!silent) |
1bd0a3ae | 1957 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 1958 | goto out_err; |
e9be9d5e MS |
1959 | } |
1960 | ||
b8e42a65 MS |
1961 | err = -ENOMEM; |
1962 | splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); | |
1963 | if (!splitlower) | |
1964 | goto out_err; | |
1965 | ||
1966 | numlower = ovl_split_lowerdirs(splitlower); | |
1967 | if (numlower > OVL_MAX_STACK) { | |
1968 | pr_err("too many lower directories, limit is %d\n", | |
1969 | OVL_MAX_STACK); | |
1970 | goto out_err; | |
1971 | } | |
1972 | ||
1973 | layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); | |
1974 | if (!layers) | |
1975 | goto out_err; | |
1976 | ||
1977 | ofs->layers = layers; | |
1978 | /* Layer 0 is reserved for upper even if there's no upper */ | |
1979 | ofs->numlayer = 1; | |
1980 | ||
53a08cb9 | 1981 | sb->s_stack_depth = 0; |
cf9a6784 | 1982 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 1983 | atomic_long_set(&ofs->last_ino, 1); |
e487d889 | 1984 | /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 1985 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 1986 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
1987 | if (!ofs->xino_mode) { |
1988 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
1989 | ofs->config.xino = OVL_XINO_OFF; | |
1990 | } | |
1991 | } | |
795939a9 | 1992 | |
146d62e5 AG |
1993 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
1994 | sb->s_op = &ovl_super_operations; | |
1995 | ||
ad204488 MS |
1996 | if (ofs->config.upperdir) { |
1997 | if (!ofs->config.workdir) { | |
1bd0a3ae | 1998 | pr_err("missing 'workdir'\n"); |
a9075cdb | 1999 | goto out_err; |
53a08cb9 | 2000 | } |
e9be9d5e | 2001 | |
b8e42a65 | 2002 | err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); |
53a08cb9 | 2003 | if (err) |
a9075cdb | 2004 | goto out_err; |
2cac0c00 | 2005 | |
146d62e5 | 2006 | err = ovl_get_workdir(sb, ofs, &upperpath); |
8ed61dc3 | 2007 | if (err) |
a9075cdb | 2008 | goto out_err; |
c6fe6254 | 2009 | |
ad204488 | 2010 | if (!ofs->workdir) |
1751e8a6 | 2011 | sb->s_flags |= SB_RDONLY; |
6e88256e | 2012 | |
08f4c7c8 MS |
2013 | sb->s_stack_depth = ovl_upper_mnt(ofs)->mnt_sb->s_stack_depth; |
2014 | sb->s_time_gran = ovl_upper_mnt(ofs)->mnt_sb->s_time_gran; | |
c6fe6254 | 2015 | |
e9be9d5e | 2016 | } |
b8e42a65 | 2017 | oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); |
4155c10a MS |
2018 | err = PTR_ERR(oe); |
2019 | if (IS_ERR(oe)) | |
a9075cdb | 2020 | goto out_err; |
e9be9d5e | 2021 | |
71cbad7e | 2022 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 2023 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 2024 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 2025 | |
5830fb6b PT |
2026 | if (!ofs->config.uuid && ofs->numfs > 1) { |
2027 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); | |
2028 | ofs->config.uuid = true; | |
2029 | } | |
2030 | ||
470c1563 | 2031 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
146d62e5 | 2032 | err = ovl_get_indexdir(sb, ofs, oe, &upperpath); |
54fb347e | 2033 | if (err) |
4155c10a | 2034 | goto out_free_oe; |
6e88256e | 2035 | |
972d0093 | 2036 | /* Force r/o mount with no index dir */ |
20396365 | 2037 | if (!ofs->indexdir) |
1751e8a6 | 2038 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
2039 | } |
2040 | ||
146d62e5 AG |
2041 | err = ovl_check_overlapping_layers(sb, ofs); |
2042 | if (err) | |
2043 | goto out_free_oe; | |
2044 | ||
972d0093 | 2045 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 2046 | if (!ofs->indexdir) { |
ad204488 | 2047 | ofs->config.index = false; |
08f4c7c8 | 2048 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 2049 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
2050 | ofs->config.nfs_export = false; |
2051 | } | |
2052 | } | |
02bcd157 | 2053 | |
d5791044 | 2054 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 2055 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
2056 | ofs->config.nfs_export = false; |
2057 | } | |
2058 | ||
8383f174 AG |
2059 | if (ofs->config.nfs_export) |
2060 | sb->s_export_op = &ovl_export_operations; | |
2061 | ||
51f8f3c4 KK |
2062 | /* Never override disk quota limits or use reserved space */ |
2063 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
2064 | ||
655042cc | 2065 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
2d2f2d73 MS |
2066 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
2067 | ovl_trusted_xattr_handlers; | |
ad204488 | 2068 | sb->s_fs_info = ofs; |
de2a4a50 | 2069 | sb->s_flags |= SB_POSIXACL; |
32b1924b | 2070 | sb->s_iflags |= SB_I_SKIP_SYNC; |
655042cc | 2071 | |
c6fe6254 | 2072 | err = -ENOMEM; |
2effc5c2 | 2073 | root_dentry = ovl_get_root(sb, upperpath.dentry, oe); |
e9be9d5e | 2074 | if (!root_dentry) |
4155c10a | 2075 | goto out_free_oe; |
e9be9d5e MS |
2076 | |
2077 | mntput(upperpath.mnt); | |
b8e42a65 | 2078 | kfree(splitlower); |
ed06e069 | 2079 | |
e9be9d5e | 2080 | sb->s_root = root_dentry; |
e9be9d5e MS |
2081 | |
2082 | return 0; | |
2083 | ||
4155c10a MS |
2084 | out_free_oe: |
2085 | ovl_entry_stack_free(oe); | |
b9343632 | 2086 | kfree(oe); |
4155c10a | 2087 | out_err: |
b8e42a65 | 2088 | kfree(splitlower); |
e9be9d5e | 2089 | path_put(&upperpath); |
ad204488 | 2090 | ovl_free_fs(ofs); |
e9be9d5e MS |
2091 | out: |
2092 | return err; | |
2093 | } | |
2094 | ||
2095 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
2096 | const char *dev_name, void *raw_data) | |
2097 | { | |
2098 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
2099 | } | |
2100 | ||
2101 | static struct file_system_type ovl_fs_type = { | |
2102 | .owner = THIS_MODULE, | |
ef94b186 | 2103 | .name = "overlay", |
459c7c56 | 2104 | .fs_flags = FS_USERNS_MOUNT, |
e9be9d5e MS |
2105 | .mount = ovl_mount, |
2106 | .kill_sb = kill_anon_super, | |
2107 | }; | |
ef94b186 | 2108 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 2109 | |
13cf199d AG |
2110 | static void ovl_inode_init_once(void *foo) |
2111 | { | |
2112 | struct ovl_inode *oi = foo; | |
2113 | ||
2114 | inode_init_once(&oi->vfs_inode); | |
2115 | } | |
2116 | ||
e9be9d5e MS |
2117 | static int __init ovl_init(void) |
2118 | { | |
13cf199d AG |
2119 | int err; |
2120 | ||
2121 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
2122 | sizeof(struct ovl_inode), 0, | |
2123 | (SLAB_RECLAIM_ACCOUNT| | |
2124 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
2125 | ovl_inode_init_once); | |
2126 | if (ovl_inode_cachep == NULL) | |
2127 | return -ENOMEM; | |
2128 | ||
2406a307 JX |
2129 | err = ovl_aio_request_cache_init(); |
2130 | if (!err) { | |
2131 | err = register_filesystem(&ovl_fs_type); | |
2132 | if (!err) | |
2133 | return 0; | |
2134 | ||
2135 | ovl_aio_request_cache_destroy(); | |
2136 | } | |
2137 | kmem_cache_destroy(ovl_inode_cachep); | |
13cf199d AG |
2138 | |
2139 | return err; | |
e9be9d5e MS |
2140 | } |
2141 | ||
2142 | static void __exit ovl_exit(void) | |
2143 | { | |
2144 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
2145 | |
2146 | /* | |
2147 | * Make sure all delayed rcu free inodes are flushed before we | |
2148 | * destroy cache. | |
2149 | */ | |
2150 | rcu_barrier(); | |
2151 | kmem_cache_destroy(ovl_inode_cachep); | |
2406a307 | 2152 | ovl_aio_request_cache_destroy(); |
e9be9d5e MS |
2153 | } |
2154 | ||
2155 | module_init(ovl_init); | |
2156 | module_exit(ovl_exit); |