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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 | ||
335d3fc5 SD |
267 | ret = ovl_sync_status(ofs); |
268 | /* | |
269 | * We have to always set the err, because the return value isn't | |
270 | * checked in syncfs, and instead indirectly return an error via | |
271 | * the sb's writeback errseq, which VFS inspects after this call. | |
272 | */ | |
273 | if (ret < 0) { | |
274 | errseq_set(&sb->s_wb_err, -EIO); | |
275 | return -EIO; | |
276 | } | |
277 | ||
278 | if (!ret) | |
279 | return ret; | |
e8d4bfe3 CX |
280 | |
281 | /* | |
32b1924b KK |
282 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
283 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
284 | * |
285 | * If this is a syncfs(2) call, then we do need to call | |
286 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
287 | * called with wait == 1. | |
288 | */ | |
289 | if (!wait) | |
e593b2bf AG |
290 | return 0; |
291 | ||
08f4c7c8 | 292 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 293 | |
e593b2bf | 294 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 295 | ret = sync_filesystem(upper_sb); |
e593b2bf | 296 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 297 | |
e593b2bf AG |
298 | return ret; |
299 | } | |
300 | ||
cc259639 AW |
301 | /** |
302 | * ovl_statfs | |
303 | * @sb: The overlayfs super block | |
304 | * @buf: The struct kstatfs to fill in with stats | |
305 | * | |
306 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 307 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
308 | */ |
309 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
310 | { | |
311 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
312 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
313 | struct path path; | |
314 | int err; | |
315 | ||
4ebc5818 | 316 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
317 | |
318 | err = vfs_statfs(&path, buf); | |
319 | if (!err) { | |
6b2d5fe4 | 320 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
321 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
322 | } | |
323 | ||
324 | return err; | |
325 | } | |
326 | ||
02bcd157 | 327 | /* Will this overlay be forced to mount/remount ro? */ |
ad204488 | 328 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
02bcd157 | 329 | { |
08f4c7c8 | 330 | return (!ovl_upper_mnt(ofs) || !ofs->workdir); |
02bcd157 AG |
331 | } |
332 | ||
438c84c2 MS |
333 | static const char *ovl_redirect_mode_def(void) |
334 | { | |
335 | return ovl_redirect_dir_def ? "on" : "off"; | |
336 | } | |
337 | ||
795939a9 AG |
338 | static const char * const ovl_xino_str[] = { |
339 | "off", | |
340 | "auto", | |
341 | "on", | |
342 | }; | |
343 | ||
344 | static inline int ovl_xino_def(void) | |
345 | { | |
346 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; | |
347 | } | |
348 | ||
f45827e8 EZ |
349 | /** |
350 | * ovl_show_options | |
351 | * | |
352 | * Prints the mount options for a given superblock. | |
353 | * Returns zero; does not fail. | |
354 | */ | |
355 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
356 | { | |
357 | struct super_block *sb = dentry->d_sb; | |
ad204488 | 358 | struct ovl_fs *ofs = sb->s_fs_info; |
f45827e8 | 359 | |
ad204488 MS |
360 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
361 | if (ofs->config.upperdir) { | |
362 | seq_show_option(m, "upperdir", ofs->config.upperdir); | |
363 | seq_show_option(m, "workdir", ofs->config.workdir); | |
53a08cb9 | 364 | } |
ad204488 | 365 | if (ofs->config.default_permissions) |
8d3095f4 | 366 | seq_puts(m, ",default_permissions"); |
438c84c2 MS |
367 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
368 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); | |
ad204488 | 369 | if (ofs->config.index != ovl_index_def) |
438c84c2 | 370 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
5830fb6b PT |
371 | if (!ofs->config.uuid) |
372 | seq_puts(m, ",uuid=off"); | |
f168f109 AG |
373 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
374 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? | |
375 | "on" : "off"); | |
0f831ec8 | 376 | if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) |
795939a9 | 377 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); |
d5791044 VG |
378 | if (ofs->config.metacopy != ovl_metacopy_def) |
379 | seq_printf(m, ",metacopy=%s", | |
380 | ofs->config.metacopy ? "on" : "off"); | |
c86243b0 VG |
381 | if (ofs->config.ovl_volatile) |
382 | seq_puts(m, ",volatile"); | |
321b46b9 GS |
383 | if (ofs->config.userxattr) |
384 | seq_puts(m, ",userxattr"); | |
f45827e8 EZ |
385 | return 0; |
386 | } | |
387 | ||
3cdf6fe9 SL |
388 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
389 | { | |
ad204488 | 390 | struct ovl_fs *ofs = sb->s_fs_info; |
399c109d CX |
391 | struct super_block *upper_sb; |
392 | int ret = 0; | |
3cdf6fe9 | 393 | |
1751e8a6 | 394 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
3cdf6fe9 SL |
395 | return -EROFS; |
396 | ||
399c109d | 397 | if (*flags & SB_RDONLY && !sb_rdonly(sb)) { |
08f4c7c8 | 398 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
c86243b0 VG |
399 | if (ovl_should_sync(ofs)) { |
400 | down_read(&upper_sb->s_umount); | |
401 | ret = sync_filesystem(upper_sb); | |
402 | up_read(&upper_sb->s_umount); | |
403 | } | |
399c109d CX |
404 | } |
405 | ||
406 | return ret; | |
3cdf6fe9 SL |
407 | } |
408 | ||
e9be9d5e | 409 | static const struct super_operations ovl_super_operations = { |
13cf199d | 410 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 411 | .free_inode = ovl_free_inode, |
13cf199d AG |
412 | .destroy_inode = ovl_destroy_inode, |
413 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 414 | .put_super = ovl_put_super, |
e593b2bf | 415 | .sync_fs = ovl_sync_fs, |
cc259639 | 416 | .statfs = ovl_statfs, |
f45827e8 | 417 | .show_options = ovl_show_options, |
3cdf6fe9 | 418 | .remount_fs = ovl_remount, |
e9be9d5e MS |
419 | }; |
420 | ||
421 | enum { | |
422 | OPT_LOWERDIR, | |
423 | OPT_UPPERDIR, | |
424 | OPT_WORKDIR, | |
8d3095f4 | 425 | OPT_DEFAULT_PERMISSIONS, |
438c84c2 | 426 | OPT_REDIRECT_DIR, |
02bcd157 AG |
427 | OPT_INDEX_ON, |
428 | OPT_INDEX_OFF, | |
5830fb6b PT |
429 | OPT_UUID_ON, |
430 | OPT_UUID_OFF, | |
f168f109 | 431 | OPT_NFS_EXPORT_ON, |
2d2f2d73 | 432 | OPT_USERXATTR, |
f168f109 | 433 | OPT_NFS_EXPORT_OFF, |
795939a9 AG |
434 | OPT_XINO_ON, |
435 | OPT_XINO_OFF, | |
436 | OPT_XINO_AUTO, | |
d5791044 VG |
437 | OPT_METACOPY_ON, |
438 | OPT_METACOPY_OFF, | |
c86243b0 | 439 | OPT_VOLATILE, |
e9be9d5e MS |
440 | OPT_ERR, |
441 | }; | |
442 | ||
443 | static const match_table_t ovl_tokens = { | |
444 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
445 | {OPT_UPPERDIR, "upperdir=%s"}, | |
446 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 447 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
438c84c2 | 448 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
02bcd157 AG |
449 | {OPT_INDEX_ON, "index=on"}, |
450 | {OPT_INDEX_OFF, "index=off"}, | |
2d2f2d73 | 451 | {OPT_USERXATTR, "userxattr"}, |
5830fb6b PT |
452 | {OPT_UUID_ON, "uuid=on"}, |
453 | {OPT_UUID_OFF, "uuid=off"}, | |
f168f109 AG |
454 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
455 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, | |
795939a9 AG |
456 | {OPT_XINO_ON, "xino=on"}, |
457 | {OPT_XINO_OFF, "xino=off"}, | |
458 | {OPT_XINO_AUTO, "xino=auto"}, | |
d5791044 VG |
459 | {OPT_METACOPY_ON, "metacopy=on"}, |
460 | {OPT_METACOPY_OFF, "metacopy=off"}, | |
c86243b0 | 461 | {OPT_VOLATILE, "volatile"}, |
e9be9d5e MS |
462 | {OPT_ERR, NULL} |
463 | }; | |
464 | ||
91c77947 MS |
465 | static char *ovl_next_opt(char **s) |
466 | { | |
467 | char *sbegin = *s; | |
468 | char *p; | |
469 | ||
470 | if (sbegin == NULL) | |
471 | return NULL; | |
472 | ||
473 | for (p = sbegin; *p; p++) { | |
474 | if (*p == '\\') { | |
475 | p++; | |
476 | if (!*p) | |
477 | break; | |
478 | } else if (*p == ',') { | |
479 | *p = '\0'; | |
480 | *s = p + 1; | |
481 | return sbegin; | |
482 | } | |
483 | } | |
484 | *s = NULL; | |
485 | return sbegin; | |
486 | } | |
487 | ||
438c84c2 MS |
488 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
489 | { | |
490 | if (strcmp(mode, "on") == 0) { | |
491 | config->redirect_dir = true; | |
492 | /* | |
493 | * Does not make sense to have redirect creation without | |
494 | * redirect following. | |
495 | */ | |
496 | config->redirect_follow = true; | |
497 | } else if (strcmp(mode, "follow") == 0) { | |
498 | config->redirect_follow = true; | |
499 | } else if (strcmp(mode, "off") == 0) { | |
500 | if (ovl_redirect_always_follow) | |
501 | config->redirect_follow = true; | |
502 | } else if (strcmp(mode, "nofollow") != 0) { | |
1bd0a3ae | 503 | pr_err("bad mount option \"redirect_dir=%s\"\n", |
438c84c2 MS |
504 | mode); |
505 | return -EINVAL; | |
506 | } | |
507 | ||
508 | return 0; | |
509 | } | |
510 | ||
e9be9d5e MS |
511 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
512 | { | |
513 | char *p; | |
d5791044 | 514 | int err; |
d47748e5 | 515 | bool metacopy_opt = false, redirect_opt = false; |
b0def88d | 516 | bool nfs_export_opt = false, index_opt = false; |
e9be9d5e | 517 | |
438c84c2 MS |
518 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
519 | if (!config->redirect_mode) | |
520 | return -ENOMEM; | |
521 | ||
91c77947 | 522 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
523 | int token; |
524 | substring_t args[MAX_OPT_ARGS]; | |
525 | ||
526 | if (!*p) | |
527 | continue; | |
528 | ||
529 | token = match_token(p, ovl_tokens, args); | |
530 | switch (token) { | |
531 | case OPT_UPPERDIR: | |
532 | kfree(config->upperdir); | |
533 | config->upperdir = match_strdup(&args[0]); | |
534 | if (!config->upperdir) | |
535 | return -ENOMEM; | |
536 | break; | |
537 | ||
538 | case OPT_LOWERDIR: | |
539 | kfree(config->lowerdir); | |
540 | config->lowerdir = match_strdup(&args[0]); | |
541 | if (!config->lowerdir) | |
542 | return -ENOMEM; | |
543 | break; | |
544 | ||
545 | case OPT_WORKDIR: | |
546 | kfree(config->workdir); | |
547 | config->workdir = match_strdup(&args[0]); | |
548 | if (!config->workdir) | |
549 | return -ENOMEM; | |
550 | break; | |
551 | ||
8d3095f4 MS |
552 | case OPT_DEFAULT_PERMISSIONS: |
553 | config->default_permissions = true; | |
554 | break; | |
555 | ||
438c84c2 MS |
556 | case OPT_REDIRECT_DIR: |
557 | kfree(config->redirect_mode); | |
558 | config->redirect_mode = match_strdup(&args[0]); | |
559 | if (!config->redirect_mode) | |
560 | return -ENOMEM; | |
d47748e5 | 561 | redirect_opt = true; |
a6c60655 MS |
562 | break; |
563 | ||
02bcd157 AG |
564 | case OPT_INDEX_ON: |
565 | config->index = true; | |
b0def88d | 566 | index_opt = true; |
02bcd157 AG |
567 | break; |
568 | ||
569 | case OPT_INDEX_OFF: | |
570 | config->index = false; | |
b0def88d | 571 | index_opt = true; |
02bcd157 AG |
572 | break; |
573 | ||
5830fb6b PT |
574 | case OPT_UUID_ON: |
575 | config->uuid = true; | |
576 | break; | |
577 | ||
578 | case OPT_UUID_OFF: | |
579 | config->uuid = false; | |
580 | break; | |
581 | ||
f168f109 AG |
582 | case OPT_NFS_EXPORT_ON: |
583 | config->nfs_export = true; | |
b0def88d | 584 | nfs_export_opt = true; |
f168f109 AG |
585 | break; |
586 | ||
587 | case OPT_NFS_EXPORT_OFF: | |
588 | config->nfs_export = false; | |
b0def88d | 589 | nfs_export_opt = true; |
f168f109 AG |
590 | break; |
591 | ||
795939a9 AG |
592 | case OPT_XINO_ON: |
593 | config->xino = OVL_XINO_ON; | |
594 | break; | |
595 | ||
596 | case OPT_XINO_OFF: | |
597 | config->xino = OVL_XINO_OFF; | |
598 | break; | |
599 | ||
600 | case OPT_XINO_AUTO: | |
601 | config->xino = OVL_XINO_AUTO; | |
602 | break; | |
603 | ||
d5791044 VG |
604 | case OPT_METACOPY_ON: |
605 | config->metacopy = true; | |
d47748e5 | 606 | metacopy_opt = true; |
d5791044 VG |
607 | break; |
608 | ||
609 | case OPT_METACOPY_OFF: | |
610 | config->metacopy = false; | |
b0def88d | 611 | metacopy_opt = true; |
d5791044 VG |
612 | break; |
613 | ||
c86243b0 VG |
614 | case OPT_VOLATILE: |
615 | config->ovl_volatile = true; | |
616 | break; | |
617 | ||
2d2f2d73 MS |
618 | case OPT_USERXATTR: |
619 | config->userxattr = true; | |
620 | break; | |
621 | ||
e9be9d5e | 622 | default: |
1bd0a3ae | 623 | pr_err("unrecognized mount option \"%s\" or missing value\n", |
624 | p); | |
e9be9d5e MS |
625 | return -EINVAL; |
626 | } | |
627 | } | |
71cbad7e | 628 | |
f0e1266e AG |
629 | /* Workdir/index are useless in non-upper mount */ |
630 | if (!config->upperdir) { | |
631 | if (config->workdir) { | |
632 | pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
633 | config->workdir); | |
634 | kfree(config->workdir); | |
635 | config->workdir = NULL; | |
636 | } | |
637 | if (config->index && index_opt) { | |
638 | pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); | |
639 | index_opt = false; | |
640 | } | |
641 | config->index = false; | |
71cbad7e | 642 | } |
643 | ||
c86243b0 VG |
644 | if (!config->upperdir && config->ovl_volatile) { |
645 | pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); | |
646 | config->ovl_volatile = false; | |
647 | } | |
648 | ||
d5791044 VG |
649 | err = ovl_parse_redirect_mode(config, config->redirect_mode); |
650 | if (err) | |
651 | return err; | |
652 | ||
d47748e5 MS |
653 | /* |
654 | * This is to make the logic below simpler. It doesn't make any other | |
655 | * difference, since config->redirect_dir is only used for upper. | |
656 | */ | |
657 | if (!config->upperdir && config->redirect_follow) | |
658 | config->redirect_dir = true; | |
659 | ||
660 | /* Resolve metacopy -> redirect_dir dependency */ | |
661 | if (config->metacopy && !config->redirect_dir) { | |
662 | if (metacopy_opt && redirect_opt) { | |
1bd0a3ae | 663 | pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", |
d47748e5 MS |
664 | config->redirect_mode); |
665 | return -EINVAL; | |
666 | } | |
667 | if (redirect_opt) { | |
668 | /* | |
669 | * There was an explicit redirect_dir=... that resulted | |
670 | * in this conflict. | |
671 | */ | |
1bd0a3ae | 672 | pr_info("disabling metacopy due to redirect_dir=%s\n", |
d47748e5 MS |
673 | config->redirect_mode); |
674 | config->metacopy = false; | |
675 | } else { | |
676 | /* Automatically enable redirect otherwise. */ | |
677 | config->redirect_follow = config->redirect_dir = true; | |
678 | } | |
d5791044 VG |
679 | } |
680 | ||
b0def88d AG |
681 | /* Resolve nfs_export -> index dependency */ |
682 | if (config->nfs_export && !config->index) { | |
f0e1266e AG |
683 | if (!config->upperdir && config->redirect_follow) { |
684 | pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); | |
685 | config->nfs_export = false; | |
686 | } else if (nfs_export_opt && index_opt) { | |
b0def88d AG |
687 | pr_err("conflicting options: nfs_export=on,index=off\n"); |
688 | return -EINVAL; | |
f0e1266e | 689 | } else if (index_opt) { |
b0def88d AG |
690 | /* |
691 | * There was an explicit index=off that resulted | |
692 | * in this conflict. | |
693 | */ | |
694 | pr_info("disabling nfs_export due to index=off\n"); | |
695 | config->nfs_export = false; | |
696 | } else { | |
697 | /* Automatically enable index otherwise. */ | |
698 | config->index = true; | |
699 | } | |
700 | } | |
701 | ||
702 | /* Resolve nfs_export -> !metacopy dependency */ | |
703 | if (config->nfs_export && config->metacopy) { | |
704 | if (nfs_export_opt && metacopy_opt) { | |
705 | pr_err("conflicting options: nfs_export=on,metacopy=on\n"); | |
706 | return -EINVAL; | |
707 | } | |
708 | if (metacopy_opt) { | |
709 | /* | |
710 | * There was an explicit metacopy=on that resulted | |
711 | * in this conflict. | |
712 | */ | |
713 | pr_info("disabling nfs_export due to metacopy=on\n"); | |
714 | config->nfs_export = false; | |
715 | } else { | |
716 | /* | |
717 | * There was an explicit nfs_export=on that resulted | |
718 | * in this conflict. | |
719 | */ | |
720 | pr_info("disabling metacopy due to nfs_export=on\n"); | |
721 | config->metacopy = false; | |
722 | } | |
723 | } | |
724 | ||
2d2f2d73 MS |
725 | |
726 | /* Resolve userxattr -> !redirect && !metacopy dependency */ | |
727 | if (config->userxattr) { | |
728 | if (config->redirect_follow && redirect_opt) { | |
729 | pr_err("conflicting options: userxattr,redirect_dir=%s\n", | |
730 | config->redirect_mode); | |
731 | return -EINVAL; | |
732 | } | |
733 | if (config->metacopy && metacopy_opt) { | |
734 | pr_err("conflicting options: userxattr,metacopy=on\n"); | |
735 | return -EINVAL; | |
736 | } | |
737 | /* | |
738 | * Silently disable default setting of redirect and metacopy. | |
739 | * This shall be the default in the future as well: these | |
740 | * options must be explicitly enabled if used together with | |
741 | * userxattr. | |
742 | */ | |
743 | config->redirect_dir = config->redirect_follow = false; | |
744 | config->metacopy = false; | |
745 | } | |
746 | ||
d5791044 | 747 | return 0; |
e9be9d5e MS |
748 | } |
749 | ||
750 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 751 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 752 | |
ad204488 | 753 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 754 | const char *name, bool persist) |
e9be9d5e | 755 | { |
ad204488 | 756 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 757 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
758 | struct dentry *work; |
759 | int err; | |
760 | bool retried = false; | |
761 | ||
5955102c | 762 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 763 | retry: |
ad204488 | 764 | work = lookup_one_len(name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
765 | |
766 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
767 | struct iattr attr = { |
768 | .ia_valid = ATTR_MODE, | |
32a3d848 | 769 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 770 | }; |
e9be9d5e MS |
771 | |
772 | if (work->d_inode) { | |
773 | err = -EEXIST; | |
774 | if (retried) | |
775 | goto out_dput; | |
776 | ||
6b8aa129 AG |
777 | if (persist) |
778 | goto out_unlock; | |
779 | ||
e9be9d5e | 780 | retried = true; |
235ce9ed | 781 | err = ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e | 782 | dput(work); |
235ce9ed AG |
783 | if (err == -EINVAL) { |
784 | work = ERR_PTR(err); | |
785 | goto out_unlock; | |
786 | } | |
e9be9d5e MS |
787 | goto retry; |
788 | } | |
789 | ||
e1fd40d5 MS |
790 | err = ovl_mkdir_real(dir, &work, attr.ia_mode); |
791 | if (err) | |
792 | goto out_dput; | |
793 | ||
794 | /* Weird filesystem returning with hashed negative (kernfs)? */ | |
795 | err = -EINVAL; | |
796 | if (d_really_is_negative(work)) | |
797 | goto out_dput; | |
c11b9fdd | 798 | |
cb348edb MS |
799 | /* |
800 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
801 | * | |
802 | * a) success (there was a POSIX ACL xattr and was removed) | |
803 | * b) -ENODATA (there was no POSIX ACL xattr) | |
804 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
805 | * | |
806 | * There are various other error values that could effectively | |
807 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
808 | * if the xattr name is too long), but the set of filesystems | |
809 | * allowed as upper are limited to "normal" ones, where checking | |
810 | * for the above two errors is sufficient. | |
811 | */ | |
c7c7a1a1 TA |
812 | err = vfs_removexattr(&init_user_ns, work, |
813 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
e1ff3dd1 | 814 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
815 | goto out_dput; |
816 | ||
c7c7a1a1 TA |
817 | err = vfs_removexattr(&init_user_ns, work, |
818 | XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 819 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
820 | goto out_dput; |
821 | ||
822 | /* Clear any inherited mode bits */ | |
823 | inode_lock(work->d_inode); | |
2f221d6f | 824 | err = notify_change(&init_user_ns, work, &attr, NULL); |
c11b9fdd MS |
825 | inode_unlock(work->d_inode); |
826 | if (err) | |
827 | goto out_dput; | |
6b8aa129 AG |
828 | } else { |
829 | err = PTR_ERR(work); | |
830 | goto out_err; | |
e9be9d5e MS |
831 | } |
832 | out_unlock: | |
2068cf7d | 833 | inode_unlock(dir); |
e9be9d5e MS |
834 | return work; |
835 | ||
836 | out_dput: | |
837 | dput(work); | |
6b8aa129 | 838 | out_err: |
1bd0a3ae | 839 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 840 | ofs->config.workdir, name, -err); |
6b8aa129 | 841 | work = NULL; |
e9be9d5e MS |
842 | goto out_unlock; |
843 | } | |
844 | ||
91c77947 MS |
845 | static void ovl_unescape(char *s) |
846 | { | |
847 | char *d = s; | |
848 | ||
849 | for (;; s++, d++) { | |
850 | if (*s == '\\') | |
851 | s++; | |
852 | *d = *s; | |
853 | if (!*s) | |
854 | break; | |
855 | } | |
856 | } | |
857 | ||
ab508822 MS |
858 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
859 | { | |
a78d9f0d | 860 | int err = -EINVAL; |
ab508822 | 861 | |
a78d9f0d | 862 | if (!*name) { |
1bd0a3ae | 863 | pr_err("empty lowerdir\n"); |
a78d9f0d MS |
864 | goto out; |
865 | } | |
ab508822 MS |
866 | err = kern_path(name, LOOKUP_FOLLOW, path); |
867 | if (err) { | |
1bd0a3ae | 868 | pr_err("failed to resolve '%s': %i\n", name, err); |
ab508822 MS |
869 | goto out; |
870 | } | |
871 | err = -EINVAL; | |
7c03b5d4 | 872 | if (ovl_dentry_weird(path->dentry)) { |
1bd0a3ae | 873 | pr_err("filesystem on '%s' not supported\n", name); |
ab508822 MS |
874 | goto out_put; |
875 | } | |
029a52ad CB |
876 | if (mnt_user_ns(path->mnt) != &init_user_ns) { |
877 | pr_err("idmapped layers are currently not supported\n"); | |
878 | goto out_put; | |
879 | } | |
2b8c30e9 | 880 | if (!d_is_dir(path->dentry)) { |
1bd0a3ae | 881 | pr_err("'%s' not a directory\n", name); |
ab508822 MS |
882 | goto out_put; |
883 | } | |
884 | return 0; | |
885 | ||
886 | out_put: | |
8aafcb59 | 887 | path_put_init(path); |
ab508822 MS |
888 | out: |
889 | return err; | |
890 | } | |
891 | ||
892 | static int ovl_mount_dir(const char *name, struct path *path) | |
893 | { | |
894 | int err = -ENOMEM; | |
895 | char *tmp = kstrdup(name, GFP_KERNEL); | |
896 | ||
897 | if (tmp) { | |
898 | ovl_unescape(tmp); | |
899 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 | 900 | |
73026409 CB |
901 | if (!err && (path->dentry->d_flags & DCACHE_OP_REAL && |
902 | path->dentry->d_sb->s_magic != SHIFTFS_MAGIC)) { | |
7925dad8 MS |
903 | pr_err("filesystem on '%s' not supported as upperdir\n", |
904 | tmp); | |
905 | path_put_init(path); | |
906 | err = -EINVAL; | |
907 | } | |
ab508822 MS |
908 | kfree(tmp); |
909 | } | |
910 | return err; | |
911 | } | |
912 | ||
6b2d5fe4 MS |
913 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
914 | const char *name) | |
ab508822 | 915 | { |
ab508822 | 916 | struct kstatfs statfs; |
6b2d5fe4 MS |
917 | int err = vfs_statfs(path, &statfs); |
918 | ||
919 | if (err) | |
1bd0a3ae | 920 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
921 | else |
922 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
923 | ||
924 | return err; | |
925 | } | |
926 | ||
927 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 928 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 929 | { |
e487d889 | 930 | int fh_type; |
6b2d5fe4 | 931 | int err; |
ab508822 | 932 | |
a78d9f0d | 933 | err = ovl_mount_dir_noesc(name, path); |
ab508822 | 934 | if (err) |
b8e42a65 | 935 | return err; |
ab508822 | 936 | |
6b2d5fe4 MS |
937 | err = ovl_check_namelen(path, ofs, name); |
938 | if (err) | |
b8e42a65 | 939 | return err; |
6b2d5fe4 | 940 | |
ab508822 MS |
941 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
942 | ||
02bcd157 | 943 | /* |
f168f109 AG |
944 | * The inodes index feature and NFS export need to encode and decode |
945 | * file handles, so they require that all layers support them. | |
02bcd157 | 946 | */ |
e487d889 | 947 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 948 | if ((ofs->config.nfs_export || |
e487d889 | 949 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 950 | ofs->config.index = false; |
f168f109 | 951 | ofs->config.nfs_export = false; |
1bd0a3ae | 952 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 953 | name); |
02bcd157 | 954 | } |
b0e0f697 AG |
955 | /* |
956 | * Decoding origin file handle is required for persistent st_ino. | |
957 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
958 | */ | |
959 | if (ofs->config.xino == OVL_XINO_AUTO && | |
960 | ofs->config.upperdir && !fh_type) { | |
961 | ofs->config.xino = OVL_XINO_OFF; | |
962 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", | |
963 | name); | |
964 | } | |
02bcd157 | 965 | |
e487d889 AG |
966 | /* Check if lower fs has 32bit inode numbers */ |
967 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 968 | ofs->xino_mode = -1; |
e487d889 | 969 | |
ab508822 | 970 | return 0; |
ab508822 MS |
971 | } |
972 | ||
e9be9d5e MS |
973 | /* Workdir should not be subdir of upperdir and vice versa */ |
974 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
975 | { | |
976 | bool ok = false; | |
977 | ||
978 | if (workdir != upperdir) { | |
979 | ok = (lock_rename(workdir, upperdir) == NULL); | |
980 | unlock_rename(workdir, upperdir); | |
981 | } | |
982 | return ok; | |
983 | } | |
984 | ||
a78d9f0d MS |
985 | static unsigned int ovl_split_lowerdirs(char *str) |
986 | { | |
987 | unsigned int ctr = 1; | |
988 | char *s, *d; | |
989 | ||
990 | for (s = d = str;; s++, d++) { | |
991 | if (*s == '\\') { | |
992 | s++; | |
993 | } else if (*s == ':') { | |
994 | *d = '\0'; | |
995 | ctr++; | |
996 | continue; | |
997 | } | |
998 | *d = *s; | |
999 | if (!*s) | |
1000 | break; | |
1001 | } | |
1002 | return ctr; | |
1003 | } | |
1004 | ||
0eb45fc3 AG |
1005 | static int __maybe_unused |
1006 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
1007 | struct dentry *dentry, struct inode *inode, | |
1008 | const char *name, void *buffer, size_t size) | |
1009 | { | |
1d88f183 | 1010 | return ovl_xattr_get(dentry, inode, handler->name, buffer, size); |
0eb45fc3 AG |
1011 | } |
1012 | ||
0c97be22 AG |
1013 | static int __maybe_unused |
1014 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
e65ce2a5 | 1015 | struct user_namespace *mnt_userns, |
0c97be22 AG |
1016 | struct dentry *dentry, struct inode *inode, |
1017 | const char *name, const void *value, | |
1018 | size_t size, int flags) | |
d837a49b MS |
1019 | { |
1020 | struct dentry *workdir = ovl_workdir(dentry); | |
09d8b586 | 1021 | struct inode *realinode = ovl_inode_real(inode); |
d837a49b MS |
1022 | struct posix_acl *acl = NULL; |
1023 | int err; | |
1024 | ||
1025 | /* Check that everything is OK before copy-up */ | |
1026 | if (value) { | |
1027 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
1028 | if (IS_ERR(acl)) | |
1029 | return PTR_ERR(acl); | |
1030 | } | |
1031 | err = -EOPNOTSUPP; | |
1032 | if (!IS_POSIXACL(d_inode(workdir))) | |
1033 | goto out_acl_release; | |
1034 | if (!realinode->i_op->set_acl) | |
1035 | goto out_acl_release; | |
1036 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
1037 | err = acl ? -EACCES : 0; | |
1038 | goto out_acl_release; | |
1039 | } | |
1040 | err = -EPERM; | |
21cb47be | 1041 | if (!inode_owner_or_capable(&init_user_ns, inode)) |
d837a49b MS |
1042 | goto out_acl_release; |
1043 | ||
1044 | posix_acl_release(acl); | |
1045 | ||
fd3220d3 MS |
1046 | /* |
1047 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
1048 | * be done with mounter's capabilities and so that won't do it for us). | |
1049 | */ | |
1050 | if (unlikely(inode->i_mode & S_ISGID) && | |
1051 | handler->flags == ACL_TYPE_ACCESS && | |
1052 | !in_group_p(inode->i_gid) && | |
0558c1bf | 1053 | !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) { |
fd3220d3 MS |
1054 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; |
1055 | ||
549c7297 | 1056 | err = ovl_setattr(&init_user_ns, dentry, &iattr); |
fd3220d3 MS |
1057 | if (err) |
1058 | return err; | |
1059 | } | |
1060 | ||
1d88f183 | 1061 | err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); |
ce31513a | 1062 | return err; |
d837a49b MS |
1063 | |
1064 | out_acl_release: | |
1065 | posix_acl_release(acl); | |
1066 | return err; | |
1067 | } | |
1068 | ||
0eb45fc3 AG |
1069 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
1070 | struct dentry *dentry, struct inode *inode, | |
1071 | const char *name, void *buffer, size_t size) | |
1072 | { | |
48fab5d7 | 1073 | return -EOPNOTSUPP; |
0eb45fc3 AG |
1074 | } |
1075 | ||
d837a49b | 1076 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
e65ce2a5 | 1077 | struct user_namespace *mnt_userns, |
d837a49b MS |
1078 | struct dentry *dentry, struct inode *inode, |
1079 | const char *name, const void *value, | |
1080 | size_t size, int flags) | |
1081 | { | |
48fab5d7 | 1082 | return -EOPNOTSUPP; |
d837a49b MS |
1083 | } |
1084 | ||
0eb45fc3 AG |
1085 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
1086 | struct dentry *dentry, struct inode *inode, | |
1087 | const char *name, void *buffer, size_t size) | |
1088 | { | |
1d88f183 | 1089 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
1090 | } |
1091 | ||
0e585ccc | 1092 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
e65ce2a5 | 1093 | struct user_namespace *mnt_userns, |
0e585ccc AG |
1094 | struct dentry *dentry, struct inode *inode, |
1095 | const char *name, const void *value, | |
1096 | size_t size, int flags) | |
1097 | { | |
1d88f183 | 1098 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
1099 | } |
1100 | ||
0c97be22 AG |
1101 | static const struct xattr_handler __maybe_unused |
1102 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
1103 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
1104 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 1105 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
1106 | .set = ovl_posix_acl_xattr_set, |
1107 | }; | |
1108 | ||
0c97be22 AG |
1109 | static const struct xattr_handler __maybe_unused |
1110 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
1111 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
1112 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 1113 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
1114 | .set = ovl_posix_acl_xattr_set, |
1115 | }; | |
1116 | ||
2d2f2d73 MS |
1117 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
1118 | .prefix = OVL_XATTR_TRUSTED_PREFIX, | |
1119 | .get = ovl_own_xattr_get, | |
1120 | .set = ovl_own_xattr_set, | |
1121 | }; | |
1122 | ||
1123 | static const struct xattr_handler ovl_own_user_xattr_handler = { | |
1124 | .prefix = OVL_XATTR_USER_PREFIX, | |
0eb45fc3 | 1125 | .get = ovl_own_xattr_get, |
d837a49b MS |
1126 | .set = ovl_own_xattr_set, |
1127 | }; | |
1128 | ||
1129 | static const struct xattr_handler ovl_other_xattr_handler = { | |
1130 | .prefix = "", /* catch all */ | |
0eb45fc3 | 1131 | .get = ovl_other_xattr_get, |
d837a49b MS |
1132 | .set = ovl_other_xattr_set, |
1133 | }; | |
1134 | ||
2d2f2d73 MS |
1135 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
1136 | #ifdef CONFIG_FS_POSIX_ACL | |
1137 | &ovl_posix_acl_access_xattr_handler, | |
1138 | &ovl_posix_acl_default_xattr_handler, | |
1139 | #endif | |
1140 | &ovl_own_trusted_xattr_handler, | |
1141 | &ovl_other_xattr_handler, | |
1142 | NULL | |
1143 | }; | |
1144 | ||
1145 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { | |
0c97be22 | 1146 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
1147 | &ovl_posix_acl_access_xattr_handler, |
1148 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 1149 | #endif |
2d2f2d73 | 1150 | &ovl_own_user_xattr_handler, |
d837a49b MS |
1151 | &ovl_other_xattr_handler, |
1152 | NULL | |
1153 | }; | |
1154 | ||
146d62e5 AG |
1155 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
1156 | struct inode **ptrap, const char *name) | |
1157 | { | |
1158 | struct inode *trap; | |
1159 | int err; | |
1160 | ||
1161 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
1162 | err = PTR_ERR_OR_ZERO(trap); |
1163 | if (err) { | |
146d62e5 | 1164 | if (err == -ELOOP) |
1bd0a3ae | 1165 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
1166 | return err; |
1167 | } | |
1168 | ||
1169 | *ptrap = trap; | |
1170 | return 0; | |
1171 | } | |
1172 | ||
0be0bfd2 AG |
1173 | /* |
1174 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
1175 | * index feature. This is papering over mount leaks of container runtimes, | |
1176 | * for example, an old overlay mount is leaked and now its upperdir is | |
1177 | * attempted to be used as a lower layer in a new overlay mount. | |
1178 | */ | |
1179 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
1180 | { | |
1181 | if (ofs->config.index) { | |
1bd0a3ae | 1182 | 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 |
1183 | name); |
1184 | return -EBUSY; | |
1185 | } else { | |
1bd0a3ae | 1186 | 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 |
1187 | name); |
1188 | return 0; | |
1189 | } | |
1190 | } | |
1191 | ||
146d62e5 | 1192 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 | 1193 | struct ovl_layer *upper_layer, struct path *upperpath) |
6ee8acf0 | 1194 | { |
5064975e | 1195 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
1196 | int err; |
1197 | ||
ad204488 | 1198 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
6ee8acf0 MS |
1199 | if (err) |
1200 | goto out; | |
1201 | ||
e21a6c57 AG |
1202 | /* Upperdir path should not be r/o */ |
1203 | if (__mnt_is_readonly(upperpath->mnt)) { | |
1bd0a3ae | 1204 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
1205 | err = -EINVAL; |
1206 | goto out; | |
1207 | } | |
1208 | ||
ad204488 | 1209 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
1210 | if (err) |
1211 | goto out; | |
1212 | ||
b8e42a65 | 1213 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
1214 | "upperdir"); |
1215 | if (err) | |
1216 | goto out; | |
1217 | ||
5064975e MS |
1218 | upper_mnt = clone_private_mount(upperpath); |
1219 | err = PTR_ERR(upper_mnt); | |
1220 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 1221 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
1222 | goto out; |
1223 | } | |
1224 | ||
1225 | /* Don't inherit atime flags */ | |
1226 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
1227 | upper_layer->mnt = upper_mnt; |
1228 | upper_layer->idx = 0; | |
1229 | upper_layer->fsid = 0; | |
8c25741a | 1230 | |
654255fa JX |
1231 | /* |
1232 | * Inherit SB_NOSEC flag from upperdir. | |
1233 | * | |
1234 | * This optimization changes behavior when a security related attribute | |
1235 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
1236 | * okay because we don't yet have guarantees in that case, but it will | |
1237 | * need careful treatment once we want to honour changes to underlying | |
1238 | * filesystems. | |
1239 | */ | |
1240 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
1241 | sb->s_flags |= SB_NOSEC; | |
1242 | ||
08f4c7c8 | 1243 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 1244 | ofs->upperdir_locked = true; |
8c25741a | 1245 | } else { |
0be0bfd2 AG |
1246 | err = ovl_report_in_use(ofs, "upperdir"); |
1247 | if (err) | |
1248 | goto out; | |
8c25741a MS |
1249 | } |
1250 | ||
6ee8acf0 MS |
1251 | err = 0; |
1252 | out: | |
1253 | return err; | |
1254 | } | |
1255 | ||
cad218ab AG |
1256 | /* |
1257 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
1258 | * negative values if error is encountered. | |
1259 | */ | |
1260 | static int ovl_check_rename_whiteout(struct dentry *workdir) | |
1261 | { | |
1262 | struct inode *dir = d_inode(workdir); | |
1263 | struct dentry *temp; | |
1264 | struct dentry *dest; | |
1265 | struct dentry *whiteout; | |
1266 | struct name_snapshot name; | |
1267 | int err; | |
1268 | ||
1269 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
1270 | ||
1271 | temp = ovl_create_temp(workdir, OVL_CATTR(S_IFREG | 0)); | |
1272 | err = PTR_ERR(temp); | |
1273 | if (IS_ERR(temp)) | |
1274 | goto out_unlock; | |
1275 | ||
1276 | dest = ovl_lookup_temp(workdir); | |
1277 | err = PTR_ERR(dest); | |
1278 | if (IS_ERR(dest)) { | |
1279 | dput(temp); | |
1280 | goto out_unlock; | |
1281 | } | |
1282 | ||
1283 | /* Name is inline and stable - using snapshot as a copy helper */ | |
1284 | take_dentry_name_snapshot(&name, temp); | |
1285 | err = ovl_do_rename(dir, temp, dir, dest, RENAME_WHITEOUT); | |
1286 | if (err) { | |
1287 | if (err == -EINVAL) | |
1288 | err = 0; | |
1289 | goto cleanup_temp; | |
1290 | } | |
1291 | ||
1292 | whiteout = lookup_one_len(name.name.name, workdir, name.name.len); | |
1293 | err = PTR_ERR(whiteout); | |
1294 | if (IS_ERR(whiteout)) | |
1295 | goto cleanup_temp; | |
1296 | ||
1297 | err = ovl_is_whiteout(whiteout); | |
1298 | ||
1299 | /* Best effort cleanup of whiteout and temp file */ | |
1300 | if (err) | |
1301 | ovl_cleanup(dir, whiteout); | |
1302 | dput(whiteout); | |
1303 | ||
1304 | cleanup_temp: | |
1305 | ovl_cleanup(dir, temp); | |
1306 | release_dentry_name_snapshot(&name); | |
1307 | dput(temp); | |
1308 | dput(dest); | |
1309 | ||
1310 | out_unlock: | |
1311 | inode_unlock(dir); | |
1312 | ||
1313 | return err; | |
1314 | } | |
1315 | ||
c86243b0 VG |
1316 | static struct dentry *ovl_lookup_or_create(struct dentry *parent, |
1317 | const char *name, umode_t mode) | |
1318 | { | |
1319 | size_t len = strlen(name); | |
1320 | struct dentry *child; | |
1321 | ||
1322 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
1323 | child = lookup_one_len(name, parent, len); | |
1324 | if (!IS_ERR(child) && !child->d_inode) | |
1325 | child = ovl_create_real(parent->d_inode, child, | |
1326 | OVL_CATTR(mode)); | |
1327 | inode_unlock(parent->d_inode); | |
1328 | dput(parent); | |
1329 | ||
1330 | return child; | |
1331 | } | |
1332 | ||
1333 | /* | |
1334 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
1335 | * present. | |
1336 | */ | |
1337 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
1338 | { | |
1339 | unsigned int ctr; | |
1340 | struct dentry *d = dget(ofs->workbasedir); | |
1341 | static const char *const volatile_path[] = { | |
1342 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
1343 | }; | |
1344 | const char *const *name = volatile_path; | |
1345 | ||
1346 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
1347 | d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG); | |
1348 | if (IS_ERR(d)) | |
1349 | return PTR_ERR(d); | |
1350 | } | |
1351 | dput(d); | |
1352 | return 0; | |
1353 | } | |
1354 | ||
146d62e5 AG |
1355 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
1356 | struct path *workpath) | |
8ed61dc3 | 1357 | { |
08f4c7c8 | 1358 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 1359 | struct dentry *temp, *workdir; |
d80172c2 AG |
1360 | bool rename_whiteout; |
1361 | bool d_type; | |
e487d889 | 1362 | int fh_type; |
8ed61dc3 MS |
1363 | int err; |
1364 | ||
2ba9d57e AG |
1365 | err = mnt_want_write(mnt); |
1366 | if (err) | |
1367 | return err; | |
1368 | ||
235ce9ed AG |
1369 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
1370 | err = PTR_ERR(workdir); | |
1371 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 1372 | goto out; |
8ed61dc3 | 1373 | |
235ce9ed AG |
1374 | ofs->workdir = workdir; |
1375 | ||
146d62e5 AG |
1376 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
1377 | if (err) | |
1378 | goto out; | |
1379 | ||
8ed61dc3 MS |
1380 | /* |
1381 | * Upper should support d_type, else whiteouts are visible. Given | |
1382 | * workdir and upper are on same fs, we can do iterate_dir() on | |
1383 | * workdir. This check requires successful creation of workdir in | |
1384 | * previous step. | |
1385 | */ | |
1386 | err = ovl_check_d_type_supported(workpath); | |
1387 | if (err < 0) | |
2ba9d57e | 1388 | goto out; |
8ed61dc3 | 1389 | |
d80172c2 AG |
1390 | d_type = err; |
1391 | if (!d_type) | |
1bd0a3ae | 1392 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
1393 | |
1394 | /* Check if upper/work fs supports O_TMPFILE */ | |
ad204488 MS |
1395 | temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); |
1396 | ofs->tmpfile = !IS_ERR(temp); | |
1397 | if (ofs->tmpfile) | |
8ed61dc3 MS |
1398 | dput(temp); |
1399 | else | |
1bd0a3ae | 1400 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 1401 | |
cad218ab AG |
1402 | |
1403 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
1404 | err = ovl_check_rename_whiteout(ofs->workdir); | |
1405 | if (err < 0) | |
1406 | goto out; | |
1407 | ||
d80172c2 AG |
1408 | rename_whiteout = err; |
1409 | if (!rename_whiteout) | |
cad218ab AG |
1410 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
1411 | ||
8ed61dc3 | 1412 | /* |
2d2f2d73 | 1413 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 1414 | */ |
610afc0b | 1415 | err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 1416 | if (err) { |
ad204488 | 1417 | ofs->noxattr = true; |
b0e0f697 AG |
1418 | if (ofs->config.index || ofs->config.metacopy) { |
1419 | ofs->config.index = false; | |
1420 | ofs->config.metacopy = false; | |
1421 | pr_warn("upper fs does not support xattr, falling back to index=off,metacopy=off.\n"); | |
1422 | } | |
1423 | /* | |
1424 | * xattr support is required for persistent st_ino. | |
1425 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
1426 | */ | |
1427 | if (ofs->config.xino == OVL_XINO_AUTO) { | |
1428 | ofs->config.xino = OVL_XINO_OFF; | |
1429 | pr_warn("upper fs does not support xattr, falling back to xino=off.\n"); | |
1430 | } | |
2ba9d57e | 1431 | err = 0; |
8ed61dc3 | 1432 | } else { |
610afc0b | 1433 | ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
1434 | } |
1435 | ||
d80172c2 AG |
1436 | /* |
1437 | * We allowed sub-optimal upper fs configuration and don't want to break | |
1438 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
1439 | * we can enforce strict requirements for remote upper fs. | |
1440 | */ | |
1441 | if (ovl_dentry_remote(ofs->workdir) && | |
1442 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
1443 | pr_err("upper fs missing required features.\n"); | |
1444 | err = -EINVAL; | |
1445 | goto out; | |
1446 | } | |
1447 | ||
c86243b0 VG |
1448 | /* |
1449 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
1450 | * track of it. | |
1451 | */ | |
1452 | if (ofs->config.ovl_volatile) { | |
1453 | err = ovl_create_volatile_dirty(ofs); | |
1454 | if (err < 0) { | |
1455 | pr_err("Failed to create volatile/dirty file.\n"); | |
1456 | goto out; | |
1457 | } | |
1458 | } | |
1459 | ||
8ed61dc3 | 1460 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
1461 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
1462 | if (ofs->config.index && !fh_type) { | |
ad204488 | 1463 | ofs->config.index = false; |
1bd0a3ae | 1464 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 MS |
1465 | } |
1466 | ||
e487d889 AG |
1467 | /* Check if upper fs has 32bit inode numbers */ |
1468 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 1469 | ofs->xino_mode = -1; |
e487d889 | 1470 | |
f168f109 AG |
1471 | /* NFS export of r/w mount depends on index */ |
1472 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 1473 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
1474 | ofs->config.nfs_export = false; |
1475 | } | |
2ba9d57e AG |
1476 | out: |
1477 | mnt_drop_write(mnt); | |
1478 | return err; | |
8ed61dc3 MS |
1479 | } |
1480 | ||
146d62e5 AG |
1481 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
1482 | struct path *upperpath) | |
520d7c86 MS |
1483 | { |
1484 | int err; | |
bca44b52 | 1485 | struct path workpath = { }; |
520d7c86 | 1486 | |
ad204488 | 1487 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
520d7c86 MS |
1488 | if (err) |
1489 | goto out; | |
1490 | ||
1491 | err = -EINVAL; | |
bca44b52 | 1492 | if (upperpath->mnt != workpath.mnt) { |
1bd0a3ae | 1493 | pr_err("workdir and upperdir must reside under the same mount\n"); |
520d7c86 MS |
1494 | goto out; |
1495 | } | |
bca44b52 | 1496 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
1bd0a3ae | 1497 | pr_err("workdir and upperdir must be separate subtrees\n"); |
520d7c86 MS |
1498 | goto out; |
1499 | } | |
1500 | ||
8c25741a MS |
1501 | ofs->workbasedir = dget(workpath.dentry); |
1502 | ||
8c25741a | 1503 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 1504 | ofs->workdir_locked = true; |
520d7c86 | 1505 | } else { |
0be0bfd2 AG |
1506 | err = ovl_report_in_use(ofs, "workdir"); |
1507 | if (err) | |
1508 | goto out; | |
520d7c86 MS |
1509 | } |
1510 | ||
0be0bfd2 AG |
1511 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
1512 | "workdir"); | |
1513 | if (err) | |
1514 | goto out; | |
1515 | ||
146d62e5 | 1516 | err = ovl_make_workdir(sb, ofs, &workpath); |
bca44b52 | 1517 | |
520d7c86 | 1518 | out: |
bca44b52 MS |
1519 | path_put(&workpath); |
1520 | ||
520d7c86 MS |
1521 | return err; |
1522 | } | |
1523 | ||
146d62e5 AG |
1524 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
1525 | struct ovl_entry *oe, struct path *upperpath) | |
f7e3a7d9 | 1526 | { |
08f4c7c8 | 1527 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 1528 | struct dentry *indexdir; |
f7e3a7d9 MS |
1529 | int err; |
1530 | ||
2ba9d57e AG |
1531 | err = mnt_want_write(mnt); |
1532 | if (err) | |
1533 | return err; | |
1534 | ||
f7e3a7d9 | 1535 | /* Verify lower root is upper root origin */ |
610afc0b MS |
1536 | err = ovl_verify_origin(ofs, upperpath->dentry, |
1537 | oe->lowerstack[0].dentry, true); | |
f7e3a7d9 | 1538 | if (err) { |
1bd0a3ae | 1539 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
1540 | goto out; |
1541 | } | |
1542 | ||
470c1563 AG |
1543 | /* index dir will act also as workdir */ |
1544 | iput(ofs->workdir_trap); | |
1545 | ofs->workdir_trap = NULL; | |
1546 | dput(ofs->workdir); | |
1547 | ofs->workdir = NULL; | |
235ce9ed AG |
1548 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
1549 | if (IS_ERR(indexdir)) { | |
1550 | err = PTR_ERR(indexdir); | |
1551 | } else if (indexdir) { | |
1552 | ofs->indexdir = indexdir; | |
1553 | ofs->workdir = dget(indexdir); | |
20396365 | 1554 | |
146d62e5 AG |
1555 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
1556 | "indexdir"); | |
1557 | if (err) | |
1558 | goto out; | |
1559 | ||
ad1d615c AG |
1560 | /* |
1561 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 1562 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
1563 | * xattr. If that xattr exists, verify that it is a match to |
1564 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 1565 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
1566 | * directory entries. |
1567 | */ | |
610afc0b MS |
1568 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
1569 | err = ovl_verify_set_fh(ofs, ofs->indexdir, | |
1570 | OVL_XATTR_ORIGIN, | |
ad1d615c AG |
1571 | upperpath->dentry, true, false); |
1572 | if (err) | |
1bd0a3ae | 1573 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 1574 | } |
610afc0b MS |
1575 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
1576 | true); | |
f7e3a7d9 | 1577 | if (err) |
1bd0a3ae | 1578 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
1579 | |
1580 | /* Cleanup bad/stale/orphan index entries */ | |
1581 | if (!err) | |
1eff1a1d | 1582 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 1583 | } |
ad204488 | 1584 | if (err || !ofs->indexdir) |
1bd0a3ae | 1585 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
1586 | |
1587 | out: | |
2ba9d57e | 1588 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
1589 | return err; |
1590 | } | |
1591 | ||
9df085f3 AG |
1592 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
1593 | { | |
1594 | unsigned int i; | |
1595 | ||
08f4c7c8 | 1596 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
1597 | return true; |
1598 | ||
a888db31 AG |
1599 | /* |
1600 | * We allow using single lower with null uuid for index and nfs_export | |
1601 | * for example to support those features with single lower squashfs. | |
1602 | * To avoid regressions in setups of overlay with re-formatted lower | |
1603 | * squashfs, do not allow decoding origin with lower null uuid unless | |
1604 | * user opted-in to one of the new features that require following the | |
1605 | * lower inode of non-dir upper. | |
1606 | */ | |
ca45275c | 1607 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
a888db31 AG |
1608 | return false; |
1609 | ||
1b81dddd | 1610 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
1611 | /* |
1612 | * We use uuid to associate an overlay lower file handle with a | |
1613 | * lower layer, so we can accept lower fs with null uuid as long | |
1614 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
1615 | * if we detect multiple lower fs with the same uuid, we |
1616 | * disable lower file handle decoding on all of them. | |
9df085f3 | 1617 | */ |
1b81dddd AG |
1618 | if (ofs->fs[i].is_lower && |
1619 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 1620 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 1621 | return false; |
7e63c87f | 1622 | } |
9df085f3 AG |
1623 | } |
1624 | return true; | |
1625 | } | |
1626 | ||
5148626b | 1627 | /* Get a unique fsid for the layer */ |
9df085f3 | 1628 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 1629 | { |
9df085f3 | 1630 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
1631 | unsigned int i; |
1632 | dev_t dev; | |
1633 | int err; | |
7e63c87f | 1634 | bool bad_uuid = false; |
b0e0f697 | 1635 | bool warn = false; |
5148626b | 1636 | |
07f1e596 AG |
1637 | for (i = 0; i < ofs->numfs; i++) { |
1638 | if (ofs->fs[i].sb == sb) | |
1639 | return i; | |
5148626b AG |
1640 | } |
1641 | ||
9df085f3 | 1642 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f | 1643 | bad_uuid = true; |
b0e0f697 AG |
1644 | if (ofs->config.xino == OVL_XINO_AUTO) { |
1645 | ofs->config.xino = OVL_XINO_OFF; | |
1646 | warn = true; | |
1647 | } | |
7e63c87f AG |
1648 | if (ofs->config.index || ofs->config.nfs_export) { |
1649 | ofs->config.index = false; | |
1650 | ofs->config.nfs_export = false; | |
b0e0f697 AG |
1651 | warn = true; |
1652 | } | |
1653 | if (warn) { | |
1654 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", | |
7e63c87f AG |
1655 | uuid_is_null(&sb->s_uuid) ? "null" : |
1656 | "conflicting", | |
b0e0f697 | 1657 | path->dentry, ovl_xino_str[ofs->config.xino]); |
7e63c87f | 1658 | } |
9df085f3 AG |
1659 | } |
1660 | ||
5148626b AG |
1661 | err = get_anon_bdev(&dev); |
1662 | if (err) { | |
1bd0a3ae | 1663 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
1664 | return err; |
1665 | } | |
1666 | ||
07f1e596 AG |
1667 | ofs->fs[ofs->numfs].sb = sb; |
1668 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
1669 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 1670 | |
07f1e596 | 1671 | return ofs->numfs++; |
5148626b AG |
1672 | } |
1673 | ||
94375f9d | 1674 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 MS |
1675 | struct path *stack, unsigned int numlower, |
1676 | struct ovl_layer *layers) | |
520d7c86 MS |
1677 | { |
1678 | int err; | |
1679 | unsigned int i; | |
1680 | ||
1681 | err = -ENOMEM; | |
07f1e596 AG |
1682 | ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); |
1683 | if (ofs->fs == NULL) | |
5148626b AG |
1684 | goto out; |
1685 | ||
07f1e596 AG |
1686 | /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ |
1687 | ofs->numfs++; | |
1688 | ||
07f1e596 | 1689 | /* |
b7bf9908 AG |
1690 | * All lower layers that share the same fs as upper layer, use the same |
1691 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1692 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1693 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1694 | */ |
b7bf9908 AG |
1695 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1696 | if (err) { | |
1697 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
1698 | goto out; | |
1699 | } | |
1700 | ||
08f4c7c8 MS |
1701 | if (ovl_upper_mnt(ofs)) { |
1702 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1703 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1704 | } |
1705 | ||
520d7c86 MS |
1706 | for (i = 0; i < numlower; i++) { |
1707 | struct vfsmount *mnt; | |
146d62e5 | 1708 | struct inode *trap; |
5148626b | 1709 | int fsid; |
520d7c86 | 1710 | |
9df085f3 | 1711 | err = fsid = ovl_get_fsid(ofs, &stack[i]); |
5148626b | 1712 | if (err < 0) |
520d7c86 | 1713 | goto out; |
520d7c86 | 1714 | |
24f14009 | 1715 | /* |
1716 | * Check if lower root conflicts with this overlay layers before | |
1717 | * checking if it is in-use as upperdir/workdir of "another" | |
1718 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1719 | * the upperdir/workdir is in fact in-use by our | |
1720 | * upperdir/workdir. | |
1721 | */ | |
146d62e5 AG |
1722 | err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); |
1723 | if (err) | |
1724 | goto out; | |
1725 | ||
0be0bfd2 AG |
1726 | if (ovl_is_inuse(stack[i].dentry)) { |
1727 | err = ovl_report_in_use(ofs, "lowerdir"); | |
24f14009 | 1728 | if (err) { |
1729 | iput(trap); | |
0be0bfd2 | 1730 | goto out; |
24f14009 | 1731 | } |
0be0bfd2 AG |
1732 | } |
1733 | ||
520d7c86 MS |
1734 | mnt = clone_private_mount(&stack[i]); |
1735 | err = PTR_ERR(mnt); | |
1736 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1737 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1738 | iput(trap); |
520d7c86 MS |
1739 | goto out; |
1740 | } | |
5148626b | 1741 | |
520d7c86 MS |
1742 | /* |
1743 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1744 | * will fail instead of modifying lower fs. | |
1745 | */ | |
1746 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1747 | ||
13464165 MS |
1748 | layers[ofs->numlayer].trap = trap; |
1749 | layers[ofs->numlayer].mnt = mnt; | |
1750 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1751 | layers[ofs->numlayer].fsid = fsid; | |
1752 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
94375f9d | 1753 | ofs->numlayer++; |
1b81dddd | 1754 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1755 | } |
e487d889 | 1756 | |
795939a9 AG |
1757 | /* |
1758 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1759 | * With mount option "xino=<on|auto>", mounter declares that there are |
1760 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1761 | * If overlayfs does encounter underlying inodes using the high xino |
1762 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1763 | * inode number or a non persistent inode number allocated from a |
1764 | * dedicated range. | |
795939a9 | 1765 | */ |
08f4c7c8 | 1766 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1767 | if (ofs->config.xino == OVL_XINO_ON) |
1768 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1769 | ofs->xino_mode = 0; | |
53afcd31 AG |
1770 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1771 | ofs->xino_mode = -1; | |
926e94d7 | 1772 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1773 | /* |
07f1e596 | 1774 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1775 | * fsid, where fsid 0 is reserved for upper fs (even with |
1776 | * lower only overlay) +1 extra bit is reserved for the non | |
1777 | * persistent inode number range that is used for resolving | |
1778 | * xino lower bits overflow. | |
795939a9 | 1779 | */ |
dfe51d47 AG |
1780 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1781 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1782 | } |
1783 | ||
0f831ec8 | 1784 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1785 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1786 | ofs->xino_mode); |
795939a9 | 1787 | } |
e487d889 | 1788 | |
520d7c86 MS |
1789 | err = 0; |
1790 | out: | |
1791 | return err; | |
1792 | } | |
1793 | ||
4155c10a | 1794 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b8e42a65 MS |
1795 | const char *lower, unsigned int numlower, |
1796 | struct ovl_fs *ofs, struct ovl_layer *layers) | |
53dbb0b4 MS |
1797 | { |
1798 | int err; | |
4155c10a | 1799 | struct path *stack = NULL; |
b8e42a65 | 1800 | unsigned int i; |
4155c10a | 1801 | struct ovl_entry *oe; |
53dbb0b4 | 1802 | |
b8e42a65 | 1803 | if (!ofs->config.upperdir && numlower == 1) { |
1bd0a3ae | 1804 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1805 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1806 | } |
1807 | ||
b8e42a65 | 1808 | stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); |
53dbb0b4 | 1809 | if (!stack) |
b8e42a65 | 1810 | return ERR_PTR(-ENOMEM); |
53dbb0b4 MS |
1811 | |
1812 | err = -EINVAL; | |
b8e42a65 MS |
1813 | for (i = 0; i < numlower; i++) { |
1814 | err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); | |
53dbb0b4 | 1815 | if (err) |
4155c10a | 1816 | goto out_err; |
53dbb0b4 MS |
1817 | |
1818 | lower = strchr(lower, '\0') + 1; | |
1819 | } | |
1820 | ||
1821 | err = -EINVAL; | |
1822 | sb->s_stack_depth++; | |
1823 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1824 | pr_err("maximum fs stacking depth exceeded\n"); |
4155c10a | 1825 | goto out_err; |
53dbb0b4 MS |
1826 | } |
1827 | ||
b8e42a65 | 1828 | err = ovl_get_layers(sb, ofs, stack, numlower, layers); |
4155c10a MS |
1829 | if (err) |
1830 | goto out_err; | |
1831 | ||
1832 | err = -ENOMEM; | |
1833 | oe = ovl_alloc_entry(numlower); | |
1834 | if (!oe) | |
1835 | goto out_err; | |
1836 | ||
1837 | for (i = 0; i < numlower; i++) { | |
1838 | oe->lowerstack[i].dentry = dget(stack[i].dentry); | |
94375f9d | 1839 | oe->lowerstack[i].layer = &ofs->layers[i+1]; |
4155c10a | 1840 | } |
53dbb0b4 | 1841 | |
53dbb0b4 | 1842 | out: |
53dbb0b4 MS |
1843 | for (i = 0; i < numlower; i++) |
1844 | path_put(&stack[i]); | |
1845 | kfree(stack); | |
4155c10a MS |
1846 | |
1847 | return oe; | |
1848 | ||
1849 | out_err: | |
1850 | oe = ERR_PTR(err); | |
53dbb0b4 MS |
1851 | goto out; |
1852 | } | |
1853 | ||
146d62e5 AG |
1854 | /* |
1855 | * Check if this layer root is a descendant of: | |
1856 | * - another layer of this overlayfs instance | |
1857 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1858 | */ |
0be0bfd2 | 1859 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
708fa015 MS |
1860 | struct dentry *dentry, const char *name, |
1861 | bool is_lower) | |
146d62e5 | 1862 | { |
9179c21d | 1863 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1864 | int err = 0; |
1865 | ||
9179c21d | 1866 | if (!dentry) |
146d62e5 AG |
1867 | return 0; |
1868 | ||
9179c21d MS |
1869 | parent = dget_parent(next); |
1870 | ||
1871 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1872 | while (!err && parent != next) { | |
708fa015 | 1873 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1874 | err = -ELOOP; |
1bd0a3ae | 1875 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1876 | } else if (ovl_is_inuse(parent)) { |
1877 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1878 | } |
146d62e5 | 1879 | next = parent; |
9179c21d MS |
1880 | parent = dget_parent(next); |
1881 | dput(next); | |
146d62e5 AG |
1882 | } |
1883 | ||
9179c21d | 1884 | dput(parent); |
146d62e5 AG |
1885 | |
1886 | return err; | |
1887 | } | |
1888 | ||
1889 | /* | |
1890 | * Check if any of the layers or work dirs overlap. | |
1891 | */ | |
1892 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1893 | struct ovl_fs *ofs) | |
1894 | { | |
1895 | int i, err; | |
1896 | ||
08f4c7c8 MS |
1897 | if (ovl_upper_mnt(ofs)) { |
1898 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
708fa015 | 1899 | "upperdir", false); |
146d62e5 AG |
1900 | if (err) |
1901 | return err; | |
1902 | ||
1903 | /* | |
1904 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1905 | * this instance and covers overlapping work and index dirs, | |
1906 | * unless work or index dir have been moved since created inside | |
1907 | * workbasedir. In that case, we already have their traps in | |
1908 | * inode cache and we will catch that case on lookup. | |
1909 | */ | |
708fa015 MS |
1910 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
1911 | false); | |
146d62e5 AG |
1912 | if (err) |
1913 | return err; | |
1914 | } | |
1915 | ||
94375f9d | 1916 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1917 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1918 | ofs->layers[i].mnt->mnt_root, |
708fa015 | 1919 | "lowerdir", true); |
146d62e5 AG |
1920 | if (err) |
1921 | return err; | |
1922 | } | |
1923 | ||
1924 | return 0; | |
1925 | } | |
1926 | ||
2effc5c2 AG |
1927 | static struct dentry *ovl_get_root(struct super_block *sb, |
1928 | struct dentry *upperdentry, | |
1929 | struct ovl_entry *oe) | |
1930 | { | |
1931 | struct dentry *root; | |
62c832ed AG |
1932 | struct ovl_path *lowerpath = &oe->lowerstack[0]; |
1933 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; | |
1934 | int fsid = lowerpath->layer->fsid; | |
1935 | struct ovl_inode_params oip = { | |
1936 | .upperdentry = upperdentry, | |
1937 | .lowerpath = lowerpath, | |
1938 | }; | |
2effc5c2 AG |
1939 | |
1940 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1941 | if (!root) | |
1942 | return NULL; | |
1943 | ||
1944 | root->d_fsdata = oe; | |
1945 | ||
1946 | if (upperdentry) { | |
62c832ed AG |
1947 | /* Root inode uses upper st_ino/i_ino */ |
1948 | ino = d_inode(upperdentry)->i_ino; | |
1949 | fsid = 0; | |
2effc5c2 | 1950 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1951 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1952 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1953 | } | |
1954 | ||
1955 | /* Root is always merge -> can have whiteouts */ | |
1956 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1957 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1958 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1959 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
f4288844 | 1960 | ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); |
2effc5c2 AG |
1961 | |
1962 | return root; | |
1963 | } | |
1964 | ||
e9be9d5e MS |
1965 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1966 | { | |
33006cdf | 1967 | struct path upperpath = { }; |
e9be9d5e | 1968 | struct dentry *root_dentry; |
4155c10a | 1969 | struct ovl_entry *oe; |
ad204488 | 1970 | struct ovl_fs *ofs; |
b8e42a65 | 1971 | struct ovl_layer *layers; |
51f8f3c4 | 1972 | struct cred *cred; |
b8e42a65 MS |
1973 | char *splitlower = NULL; |
1974 | unsigned int numlower; | |
e9be9d5e MS |
1975 | int err; |
1976 | ||
9efb069d MS |
1977 | err = -EIO; |
1978 | if (WARN_ON(sb->s_user_ns != current_user_ns())) | |
1979 | goto out; | |
1980 | ||
f4288844 MS |
1981 | sb->s_d_op = &ovl_dentry_operations; |
1982 | ||
f45827e8 | 1983 | err = -ENOMEM; |
ad204488 MS |
1984 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
1985 | if (!ofs) | |
e9be9d5e MS |
1986 | goto out; |
1987 | ||
d7b49b10 | 1988 | err = -ENOMEM; |
ad204488 | 1989 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1990 | if (!cred) |
1991 | goto out_err; | |
1992 | ||
c21c839b CX |
1993 | /* Is there a reason anyone would want not to share whiteouts? */ |
1994 | ofs->share_whiteout = true; | |
1995 | ||
ad204488 | 1996 | ofs->config.index = ovl_index_def; |
5830fb6b | 1997 | ofs->config.uuid = true; |
f168f109 | 1998 | ofs->config.nfs_export = ovl_nfs_export_def; |
795939a9 | 1999 | ofs->config.xino = ovl_xino_def(); |
d5791044 | 2000 | ofs->config.metacopy = ovl_metacopy_def; |
ad204488 | 2001 | err = ovl_parse_opt((char *) data, &ofs->config); |
f45827e8 | 2002 | if (err) |
a9075cdb | 2003 | goto out_err; |
f45827e8 | 2004 | |
e9be9d5e | 2005 | err = -EINVAL; |
ad204488 | 2006 | if (!ofs->config.lowerdir) { |
07f2af7b | 2007 | if (!silent) |
1bd0a3ae | 2008 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 2009 | goto out_err; |
e9be9d5e MS |
2010 | } |
2011 | ||
b8e42a65 MS |
2012 | err = -ENOMEM; |
2013 | splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); | |
2014 | if (!splitlower) | |
2015 | goto out_err; | |
2016 | ||
d7b49b10 | 2017 | err = -EINVAL; |
b8e42a65 MS |
2018 | numlower = ovl_split_lowerdirs(splitlower); |
2019 | if (numlower > OVL_MAX_STACK) { | |
2020 | pr_err("too many lower directories, limit is %d\n", | |
2021 | OVL_MAX_STACK); | |
2022 | goto out_err; | |
2023 | } | |
2024 | ||
d7b49b10 | 2025 | err = -ENOMEM; |
b8e42a65 MS |
2026 | layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
2027 | if (!layers) | |
2028 | goto out_err; | |
2029 | ||
2030 | ofs->layers = layers; | |
2031 | /* Layer 0 is reserved for upper even if there's no upper */ | |
2032 | ofs->numlayer = 1; | |
2033 | ||
53a08cb9 | 2034 | sb->s_stack_depth = 0; |
cf9a6784 | 2035 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 2036 | atomic_long_set(&ofs->last_ino, 1); |
e487d889 | 2037 | /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 2038 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 2039 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
2040 | if (!ofs->xino_mode) { |
2041 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
2042 | ofs->config.xino = OVL_XINO_OFF; | |
2043 | } | |
2044 | } | |
795939a9 | 2045 | |
146d62e5 AG |
2046 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
2047 | sb->s_op = &ovl_super_operations; | |
2048 | ||
ad204488 | 2049 | if (ofs->config.upperdir) { |
335d3fc5 SD |
2050 | struct super_block *upper_sb; |
2051 | ||
d7b49b10 | 2052 | err = -EINVAL; |
ad204488 | 2053 | if (!ofs->config.workdir) { |
1bd0a3ae | 2054 | pr_err("missing 'workdir'\n"); |
a9075cdb | 2055 | goto out_err; |
53a08cb9 | 2056 | } |
e9be9d5e | 2057 | |
b8e42a65 | 2058 | err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); |
53a08cb9 | 2059 | if (err) |
a9075cdb | 2060 | goto out_err; |
2cac0c00 | 2061 | |
335d3fc5 SD |
2062 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
2063 | if (!ovl_should_sync(ofs)) { | |
2064 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); | |
2065 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { | |
2066 | err = -EIO; | |
2067 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); | |
2068 | goto out_err; | |
2069 | } | |
2070 | } | |
2071 | ||
146d62e5 | 2072 | err = ovl_get_workdir(sb, ofs, &upperpath); |
8ed61dc3 | 2073 | if (err) |
a9075cdb | 2074 | goto out_err; |
c6fe6254 | 2075 | |
ad204488 | 2076 | if (!ofs->workdir) |
1751e8a6 | 2077 | sb->s_flags |= SB_RDONLY; |
6e88256e | 2078 | |
335d3fc5 SD |
2079 | sb->s_stack_depth = upper_sb->s_stack_depth; |
2080 | sb->s_time_gran = upper_sb->s_time_gran; | |
e9be9d5e | 2081 | } |
b8e42a65 | 2082 | oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); |
4155c10a MS |
2083 | err = PTR_ERR(oe); |
2084 | if (IS_ERR(oe)) | |
a9075cdb | 2085 | goto out_err; |
e9be9d5e | 2086 | |
71cbad7e | 2087 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 2088 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 2089 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 2090 | |
5830fb6b PT |
2091 | if (!ofs->config.uuid && ofs->numfs > 1) { |
2092 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); | |
2093 | ofs->config.uuid = true; | |
2094 | } | |
2095 | ||
470c1563 | 2096 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
146d62e5 | 2097 | err = ovl_get_indexdir(sb, ofs, oe, &upperpath); |
54fb347e | 2098 | if (err) |
4155c10a | 2099 | goto out_free_oe; |
6e88256e | 2100 | |
972d0093 | 2101 | /* Force r/o mount with no index dir */ |
20396365 | 2102 | if (!ofs->indexdir) |
1751e8a6 | 2103 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
2104 | } |
2105 | ||
146d62e5 AG |
2106 | err = ovl_check_overlapping_layers(sb, ofs); |
2107 | if (err) | |
2108 | goto out_free_oe; | |
2109 | ||
972d0093 | 2110 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 2111 | if (!ofs->indexdir) { |
ad204488 | 2112 | ofs->config.index = false; |
08f4c7c8 | 2113 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 2114 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
2115 | ofs->config.nfs_export = false; |
2116 | } | |
2117 | } | |
02bcd157 | 2118 | |
d5791044 | 2119 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 2120 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
2121 | ofs->config.nfs_export = false; |
2122 | } | |
2123 | ||
8383f174 AG |
2124 | if (ofs->config.nfs_export) |
2125 | sb->s_export_op = &ovl_export_operations; | |
2126 | ||
51f8f3c4 KK |
2127 | /* Never override disk quota limits or use reserved space */ |
2128 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
2129 | ||
655042cc | 2130 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
2d2f2d73 MS |
2131 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
2132 | ovl_trusted_xattr_handlers; | |
ad204488 | 2133 | sb->s_fs_info = ofs; |
de2a4a50 | 2134 | sb->s_flags |= SB_POSIXACL; |
32b1924b | 2135 | sb->s_iflags |= SB_I_SKIP_SYNC; |
655042cc | 2136 | |
c6fe6254 | 2137 | err = -ENOMEM; |
2effc5c2 | 2138 | root_dentry = ovl_get_root(sb, upperpath.dentry, oe); |
e9be9d5e | 2139 | if (!root_dentry) |
4155c10a | 2140 | goto out_free_oe; |
e9be9d5e MS |
2141 | |
2142 | mntput(upperpath.mnt); | |
b8e42a65 | 2143 | kfree(splitlower); |
ed06e069 | 2144 | |
e9be9d5e | 2145 | sb->s_root = root_dentry; |
e9be9d5e MS |
2146 | |
2147 | return 0; | |
2148 | ||
4155c10a MS |
2149 | out_free_oe: |
2150 | ovl_entry_stack_free(oe); | |
b9343632 | 2151 | kfree(oe); |
4155c10a | 2152 | out_err: |
b8e42a65 | 2153 | kfree(splitlower); |
e9be9d5e | 2154 | path_put(&upperpath); |
ad204488 | 2155 | ovl_free_fs(ofs); |
e9be9d5e MS |
2156 | out: |
2157 | return err; | |
2158 | } | |
2159 | ||
2160 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
2161 | const char *dev_name, void *raw_data) | |
2162 | { | |
2163 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
2164 | } | |
2165 | ||
2166 | static struct file_system_type ovl_fs_type = { | |
2167 | .owner = THIS_MODULE, | |
ef94b186 | 2168 | .name = "overlay", |
459c7c56 | 2169 | .fs_flags = FS_USERNS_MOUNT, |
e9be9d5e MS |
2170 | .mount = ovl_mount, |
2171 | .kill_sb = kill_anon_super, | |
2172 | }; | |
ef94b186 | 2173 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 2174 | |
13cf199d AG |
2175 | static void ovl_inode_init_once(void *foo) |
2176 | { | |
2177 | struct ovl_inode *oi = foo; | |
2178 | ||
2179 | inode_init_once(&oi->vfs_inode); | |
2180 | } | |
2181 | ||
e9be9d5e MS |
2182 | static int __init ovl_init(void) |
2183 | { | |
13cf199d AG |
2184 | int err; |
2185 | ||
2186 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
2187 | sizeof(struct ovl_inode), 0, | |
2188 | (SLAB_RECLAIM_ACCOUNT| | |
2189 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
2190 | ovl_inode_init_once); | |
2191 | if (ovl_inode_cachep == NULL) | |
2192 | return -ENOMEM; | |
2193 | ||
2406a307 JX |
2194 | err = ovl_aio_request_cache_init(); |
2195 | if (!err) { | |
2196 | err = register_filesystem(&ovl_fs_type); | |
2197 | if (!err) | |
2198 | return 0; | |
2199 | ||
2200 | ovl_aio_request_cache_destroy(); | |
2201 | } | |
2202 | kmem_cache_destroy(ovl_inode_cachep); | |
13cf199d AG |
2203 | |
2204 | return err; | |
e9be9d5e MS |
2205 | } |
2206 | ||
2207 | static void __exit ovl_exit(void) | |
2208 | { | |
2209 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
2210 | |
2211 | /* | |
2212 | * Make sure all delayed rcu free inodes are flushed before we | |
2213 | * destroy cache. | |
2214 | */ | |
2215 | rcu_barrier(); | |
2216 | kmem_cache_destroy(ovl_inode_cachep); | |
2406a307 | 2217 | ovl_aio_request_cache_destroy(); |
e9be9d5e MS |
2218 | } |
2219 | ||
2220 | module_init(ovl_init); | |
2221 | module_exit(ovl_exit); |