Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
bbb1e54d MS |
2 | /* |
3 | * Copyright (C) 2011 Novell Inc. | |
4 | * Copyright (C) 2016 Red Hat, Inc. | |
bbb1e54d MS |
5 | */ |
6 | ||
7 | #include <linux/fs.h> | |
8 | #include <linux/mount.h> | |
9 | #include <linux/slab.h> | |
5b825c3a | 10 | #include <linux/cred.h> |
bbb1e54d | 11 | #include <linux/xattr.h> |
02bcd157 AG |
12 | #include <linux/exportfs.h> |
13 | #include <linux/uuid.h> | |
caf70cb2 AG |
14 | #include <linux/namei.h> |
15 | #include <linux/ratelimit.h> | |
bbb1e54d | 16 | #include "overlayfs.h" |
bbb1e54d MS |
17 | |
18 | int ovl_want_write(struct dentry *dentry) | |
19 | { | |
20 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
08f4c7c8 | 21 | return mnt_want_write(ovl_upper_mnt(ofs)); |
bbb1e54d MS |
22 | } |
23 | ||
24 | void ovl_drop_write(struct dentry *dentry) | |
25 | { | |
26 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
08f4c7c8 | 27 | mnt_drop_write(ovl_upper_mnt(ofs)); |
bbb1e54d MS |
28 | } |
29 | ||
30 | struct dentry *ovl_workdir(struct dentry *dentry) | |
31 | { | |
32 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
33 | return ofs->workdir; | |
34 | } | |
35 | ||
36 | const struct cred *ovl_override_creds(struct super_block *sb) | |
37 | { | |
38 | struct ovl_fs *ofs = sb->s_fs_info; | |
39 | ||
40 | return override_creds(ofs->creator_cred); | |
41 | } | |
42 | ||
e487d889 AG |
43 | /* |
44 | * Check if underlying fs supports file handles and try to determine encoding | |
45 | * type, in order to deduce maximum inode number used by fs. | |
46 | * | |
47 | * Return 0 if file handles are not supported. | |
48 | * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding. | |
49 | * Return -1 if fs uses a non default encoding with unknown inode size. | |
50 | */ | |
51 | int ovl_can_decode_fh(struct super_block *sb) | |
02bcd157 | 52 | { |
c846af05 MS |
53 | if (!capable(CAP_DAC_READ_SEARCH)) |
54 | return 0; | |
55 | ||
9df085f3 | 56 | if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry) |
e487d889 AG |
57 | return 0; |
58 | ||
59 | return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; | |
02bcd157 AG |
60 | } |
61 | ||
62 | struct dentry *ovl_indexdir(struct super_block *sb) | |
63 | { | |
64 | struct ovl_fs *ofs = sb->s_fs_info; | |
65 | ||
66 | return ofs->indexdir; | |
67 | } | |
68 | ||
f168f109 AG |
69 | /* Index all files on copy up. For now only enabled for NFS export */ |
70 | bool ovl_index_all(struct super_block *sb) | |
71 | { | |
72 | struct ovl_fs *ofs = sb->s_fs_info; | |
73 | ||
74 | return ofs->config.nfs_export && ofs->config.index; | |
75 | } | |
76 | ||
77 | /* Verify lower origin on lookup. For now only enabled for NFS export */ | |
78 | bool ovl_verify_lower(struct super_block *sb) | |
79 | { | |
80 | struct ovl_fs *ofs = sb->s_fs_info; | |
81 | ||
82 | return ofs->config.nfs_export && ofs->config.index; | |
83 | } | |
84 | ||
bbb1e54d MS |
85 | struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
86 | { | |
87 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); | |
88 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
89 | ||
90 | if (oe) | |
91 | oe->numlower = numlower; | |
92 | ||
93 | return oe; | |
94 | } | |
95 | ||
96 | bool ovl_dentry_remote(struct dentry *dentry) | |
97 | { | |
98 | return dentry->d_flags & | |
7925dad8 | 99 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); |
bbb1e54d MS |
100 | } |
101 | ||
f4288844 MS |
102 | void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, |
103 | unsigned int mask) | |
104 | { | |
105 | struct ovl_entry *oe = OVL_E(dentry); | |
106 | unsigned int i, flags = 0; | |
107 | ||
bccece1e MS |
108 | if (upperdentry) |
109 | flags |= upperdentry->d_flags; | |
f4288844 MS |
110 | for (i = 0; i < oe->numlower; i++) |
111 | flags |= oe->lowerstack[i].dentry->d_flags; | |
112 | ||
113 | spin_lock(&dentry->d_lock); | |
114 | dentry->d_flags &= ~mask; | |
115 | dentry->d_flags |= flags & mask; | |
116 | spin_unlock(&dentry->d_lock); | |
117 | } | |
118 | ||
bbb1e54d MS |
119 | bool ovl_dentry_weird(struct dentry *dentry) |
120 | { | |
121 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
122 | DCACHE_MANAGE_TRANSIT | | |
123 | DCACHE_OP_HASH | | |
124 | DCACHE_OP_COMPARE); | |
125 | } | |
126 | ||
127 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
128 | { | |
129 | struct ovl_entry *oe = dentry->d_fsdata; | |
130 | enum ovl_path_type type = 0; | |
131 | ||
09d8b586 | 132 | if (ovl_dentry_upper(dentry)) { |
bbb1e54d MS |
133 | type = __OVL_PATH_UPPER; |
134 | ||
135 | /* | |
59548503 | 136 | * Non-dir dentry can hold lower dentry of its copy up origin. |
bbb1e54d | 137 | */ |
59548503 | 138 | if (oe->numlower) { |
60124877 VG |
139 | if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry))) |
140 | type |= __OVL_PATH_ORIGIN; | |
0b17c28a VG |
141 | if (d_is_dir(dentry) || |
142 | !ovl_has_upperdata(d_inode(dentry))) | |
59548503 AG |
143 | type |= __OVL_PATH_MERGE; |
144 | } | |
bbb1e54d MS |
145 | } else { |
146 | if (oe->numlower > 1) | |
147 | type |= __OVL_PATH_MERGE; | |
148 | } | |
149 | return type; | |
150 | } | |
151 | ||
152 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
153 | { | |
154 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
bbb1e54d | 155 | |
08f4c7c8 | 156 | path->mnt = ovl_upper_mnt(ofs); |
09d8b586 | 157 | path->dentry = ovl_dentry_upper(dentry); |
bbb1e54d MS |
158 | } |
159 | ||
160 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
161 | { | |
162 | struct ovl_entry *oe = dentry->d_fsdata; | |
163 | ||
b9343632 CR |
164 | if (oe->numlower) { |
165 | path->mnt = oe->lowerstack[0].layer->mnt; | |
166 | path->dentry = oe->lowerstack[0].dentry; | |
167 | } else { | |
168 | *path = (struct path) { }; | |
169 | } | |
bbb1e54d MS |
170 | } |
171 | ||
4f93b426 VG |
172 | void ovl_path_lowerdata(struct dentry *dentry, struct path *path) |
173 | { | |
174 | struct ovl_entry *oe = dentry->d_fsdata; | |
175 | ||
176 | if (oe->numlower) { | |
177 | path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt; | |
178 | path->dentry = oe->lowerstack[oe->numlower - 1].dentry; | |
179 | } else { | |
180 | *path = (struct path) { }; | |
181 | } | |
182 | } | |
183 | ||
bbb1e54d MS |
184 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) |
185 | { | |
186 | enum ovl_path_type type = ovl_path_type(dentry); | |
187 | ||
188 | if (!OVL_TYPE_UPPER(type)) | |
189 | ovl_path_lower(dentry, path); | |
190 | else | |
191 | ovl_path_upper(dentry, path); | |
192 | ||
193 | return type; | |
194 | } | |
195 | ||
196 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
197 | { | |
09d8b586 | 198 | return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); |
bbb1e54d MS |
199 | } |
200 | ||
201 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
202 | { | |
203 | struct ovl_entry *oe = dentry->d_fsdata; | |
204 | ||
09d8b586 | 205 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; |
bbb1e54d MS |
206 | } |
207 | ||
13464165 | 208 | const struct ovl_layer *ovl_layer_lower(struct dentry *dentry) |
da309e8c AG |
209 | { |
210 | struct ovl_entry *oe = dentry->d_fsdata; | |
211 | ||
212 | return oe->numlower ? oe->lowerstack[0].layer : NULL; | |
213 | } | |
214 | ||
647d253f VG |
215 | /* |
216 | * ovl_dentry_lower() could return either a data dentry or metacopy dentry | |
217 | * dependig on what is stored in lowerstack[0]. At times we need to find | |
218 | * lower dentry which has data (and not metacopy dentry). This helper | |
219 | * returns the lower data dentry. | |
220 | */ | |
221 | struct dentry *ovl_dentry_lowerdata(struct dentry *dentry) | |
222 | { | |
223 | struct ovl_entry *oe = dentry->d_fsdata; | |
224 | ||
225 | return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL; | |
226 | } | |
227 | ||
bbb1e54d MS |
228 | struct dentry *ovl_dentry_real(struct dentry *dentry) |
229 | { | |
09d8b586 | 230 | return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); |
bbb1e54d MS |
231 | } |
232 | ||
1d88f183 MS |
233 | struct dentry *ovl_i_dentry_upper(struct inode *inode) |
234 | { | |
235 | return ovl_upperdentry_dereference(OVL_I(inode)); | |
236 | } | |
237 | ||
09d8b586 | 238 | struct inode *ovl_inode_upper(struct inode *inode) |
25b7713a | 239 | { |
1d88f183 | 240 | struct dentry *upperdentry = ovl_i_dentry_upper(inode); |
25b7713a | 241 | |
09d8b586 MS |
242 | return upperdentry ? d_inode(upperdentry) : NULL; |
243 | } | |
25b7713a | 244 | |
09d8b586 MS |
245 | struct inode *ovl_inode_lower(struct inode *inode) |
246 | { | |
247 | return OVL_I(inode)->lower; | |
248 | } | |
25b7713a | 249 | |
09d8b586 MS |
250 | struct inode *ovl_inode_real(struct inode *inode) |
251 | { | |
252 | return ovl_inode_upper(inode) ?: ovl_inode_lower(inode); | |
25b7713a MS |
253 | } |
254 | ||
2664bd08 VG |
255 | /* Return inode which contains lower data. Do not return metacopy */ |
256 | struct inode *ovl_inode_lowerdata(struct inode *inode) | |
257 | { | |
258 | if (WARN_ON(!S_ISREG(inode->i_mode))) | |
259 | return NULL; | |
260 | ||
261 | return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode); | |
262 | } | |
09d8b586 | 263 | |
4823d49c VG |
264 | /* Return real inode which contains data. Does not return metacopy inode */ |
265 | struct inode *ovl_inode_realdata(struct inode *inode) | |
266 | { | |
267 | struct inode *upperinode; | |
268 | ||
269 | upperinode = ovl_inode_upper(inode); | |
270 | if (upperinode && ovl_has_upperdata(inode)) | |
271 | return upperinode; | |
272 | ||
273 | return ovl_inode_lowerdata(inode); | |
274 | } | |
275 | ||
4edb83bb | 276 | struct ovl_dir_cache *ovl_dir_cache(struct inode *inode) |
bbb1e54d | 277 | { |
4edb83bb | 278 | return OVL_I(inode)->cache; |
bbb1e54d MS |
279 | } |
280 | ||
4edb83bb | 281 | void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) |
bbb1e54d | 282 | { |
4edb83bb | 283 | OVL_I(inode)->cache = cache; |
bbb1e54d MS |
284 | } |
285 | ||
c62520a8 AG |
286 | void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry) |
287 | { | |
288 | set_bit(flag, &OVL_E(dentry)->flags); | |
289 | } | |
290 | ||
291 | void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry) | |
292 | { | |
293 | clear_bit(flag, &OVL_E(dentry)->flags); | |
294 | } | |
295 | ||
296 | bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry) | |
297 | { | |
298 | return test_bit(flag, &OVL_E(dentry)->flags); | |
299 | } | |
300 | ||
bbb1e54d MS |
301 | bool ovl_dentry_is_opaque(struct dentry *dentry) |
302 | { | |
c62520a8 | 303 | return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry); |
bbb1e54d MS |
304 | } |
305 | ||
306 | bool ovl_dentry_is_whiteout(struct dentry *dentry) | |
307 | { | |
308 | return !dentry->d_inode && ovl_dentry_is_opaque(dentry); | |
309 | } | |
310 | ||
5cf5b477 | 311 | void ovl_dentry_set_opaque(struct dentry *dentry) |
bbb1e54d | 312 | { |
c62520a8 | 313 | ovl_dentry_set_flag(OVL_E_OPAQUE, dentry); |
bbb1e54d MS |
314 | } |
315 | ||
55acc661 | 316 | /* |
aa3ff3c1 AG |
317 | * For hard links and decoded file handles, it's possible for ovl_dentry_upper() |
318 | * to return positive, while there's no actual upper alias for the inode. | |
319 | * Copy up code needs to know about the existence of the upper alias, so it | |
320 | * can't use ovl_dentry_upper(). | |
55acc661 MS |
321 | */ |
322 | bool ovl_dentry_has_upper_alias(struct dentry *dentry) | |
323 | { | |
c62520a8 | 324 | return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry); |
55acc661 MS |
325 | } |
326 | ||
327 | void ovl_dentry_set_upper_alias(struct dentry *dentry) | |
328 | { | |
c62520a8 | 329 | ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry); |
55acc661 MS |
330 | } |
331 | ||
0c288874 VG |
332 | static bool ovl_should_check_upperdata(struct inode *inode) |
333 | { | |
334 | if (!S_ISREG(inode->i_mode)) | |
335 | return false; | |
336 | ||
337 | if (!ovl_inode_lower(inode)) | |
338 | return false; | |
339 | ||
340 | return true; | |
341 | } | |
342 | ||
343 | bool ovl_has_upperdata(struct inode *inode) | |
344 | { | |
345 | if (!ovl_should_check_upperdata(inode)) | |
346 | return true; | |
347 | ||
348 | if (!ovl_test_flag(OVL_UPPERDATA, inode)) | |
349 | return false; | |
350 | /* | |
351 | * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of | |
352 | * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure | |
353 | * if setting of OVL_UPPERDATA is visible, then effects of writes | |
354 | * before that are visible too. | |
355 | */ | |
356 | smp_rmb(); | |
357 | return true; | |
358 | } | |
359 | ||
360 | void ovl_set_upperdata(struct inode *inode) | |
361 | { | |
362 | /* | |
363 | * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure | |
364 | * if OVL_UPPERDATA flag is visible, then effects of write operations | |
365 | * before it are visible as well. | |
366 | */ | |
367 | smp_wmb(); | |
368 | ovl_set_flag(OVL_UPPERDATA, inode); | |
369 | } | |
370 | ||
371 | /* Caller should hold ovl_inode->lock */ | |
372 | bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags) | |
373 | { | |
374 | if (!ovl_open_flags_need_copy_up(flags)) | |
375 | return false; | |
376 | ||
377 | return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry)); | |
378 | } | |
379 | ||
380 | bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) | |
381 | { | |
382 | if (!ovl_open_flags_need_copy_up(flags)) | |
383 | return false; | |
384 | ||
385 | return !ovl_has_upperdata(d_inode(dentry)); | |
386 | } | |
387 | ||
a6c60655 MS |
388 | bool ovl_redirect_dir(struct super_block *sb) |
389 | { | |
390 | struct ovl_fs *ofs = sb->s_fs_info; | |
391 | ||
21a22878 | 392 | return ofs->config.redirect_dir && !ofs->noxattr; |
a6c60655 MS |
393 | } |
394 | ||
395 | const char *ovl_dentry_get_redirect(struct dentry *dentry) | |
396 | { | |
cf31c463 | 397 | return OVL_I(d_inode(dentry))->redirect; |
a6c60655 MS |
398 | } |
399 | ||
400 | void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) | |
401 | { | |
cf31c463 | 402 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); |
a6c60655 | 403 | |
cf31c463 MS |
404 | kfree(oi->redirect); |
405 | oi->redirect = redirect; | |
a6c60655 MS |
406 | } |
407 | ||
09d8b586 | 408 | void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) |
bbb1e54d | 409 | { |
09d8b586 | 410 | struct inode *upperinode = d_inode(upperdentry); |
e6d2ebdd | 411 | |
09d8b586 MS |
412 | WARN_ON(OVL_I(inode)->__upperdentry); |
413 | ||
25b7713a | 414 | /* |
09d8b586 | 415 | * Make sure upperdentry is consistent before making it visible |
25b7713a MS |
416 | */ |
417 | smp_wmb(); | |
09d8b586 | 418 | OVL_I(inode)->__upperdentry = upperdentry; |
31747eda | 419 | if (inode_unhashed(inode)) { |
25b7713a | 420 | inode->i_private = upperinode; |
bbb1e54d | 421 | __insert_inode_hash(inode, (unsigned long) upperinode); |
25b7713a | 422 | } |
bbb1e54d MS |
423 | } |
424 | ||
d9854c87 | 425 | static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) |
bbb1e54d | 426 | { |
04a01ac7 | 427 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 428 | |
04a01ac7 | 429 | WARN_ON(!inode_is_locked(inode)); |
4edb83bb MS |
430 | /* |
431 | * Version is used by readdir code to keep cache consistent. For merge | |
432 | * dirs all changes need to be noted. For non-merge dirs, cache only | |
433 | * contains impure (ones which have been copied up and have origins) | |
434 | * entries, so only need to note changes to impure entries. | |
435 | */ | |
436 | if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) | |
437 | OVL_I(inode)->version++; | |
bbb1e54d MS |
438 | } |
439 | ||
d9854c87 MS |
440 | void ovl_dir_modified(struct dentry *dentry, bool impurity) |
441 | { | |
442 | /* Copy mtime/ctime */ | |
443 | ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); | |
444 | ||
445 | ovl_dentry_version_inc(dentry, impurity); | |
446 | } | |
447 | ||
bbb1e54d MS |
448 | u64 ovl_dentry_version_get(struct dentry *dentry) |
449 | { | |
04a01ac7 | 450 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 451 | |
04a01ac7 MS |
452 | WARN_ON(!inode_is_locked(inode)); |
453 | return OVL_I(inode)->version; | |
bbb1e54d MS |
454 | } |
455 | ||
456 | bool ovl_is_whiteout(struct dentry *dentry) | |
457 | { | |
458 | struct inode *inode = dentry->d_inode; | |
459 | ||
460 | return inode && IS_WHITEOUT(inode); | |
461 | } | |
462 | ||
463 | struct file *ovl_path_open(struct path *path, int flags) | |
464 | { | |
56230d95 MS |
465 | struct inode *inode = d_inode(path->dentry); |
466 | int err, acc_mode; | |
467 | ||
468 | if (flags & ~(O_ACCMODE | O_LARGEFILE)) | |
469 | BUG(); | |
470 | ||
471 | switch (flags & O_ACCMODE) { | |
472 | case O_RDONLY: | |
473 | acc_mode = MAY_READ; | |
474 | break; | |
475 | case O_WRONLY: | |
476 | acc_mode = MAY_WRITE; | |
477 | break; | |
478 | default: | |
479 | BUG(); | |
480 | } | |
481 | ||
47291baa | 482 | err = inode_permission(&init_user_ns, inode, acc_mode | MAY_OPEN); |
56230d95 MS |
483 | if (err) |
484 | return ERR_PTR(err); | |
485 | ||
486 | /* O_NOATIME is an optimization, don't fail if not permitted */ | |
21cb47be | 487 | if (inode_owner_or_capable(&init_user_ns, inode)) |
56230d95 MS |
488 | flags |= O_NOATIME; |
489 | ||
490 | return dentry_open(path, flags, current_cred()); | |
bbb1e54d | 491 | } |
39d3d60a | 492 | |
0c288874 VG |
493 | /* Caller should hold ovl_inode->lock */ |
494 | static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags) | |
495 | { | |
496 | bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; | |
497 | ||
498 | if (ovl_dentry_upper(dentry) && | |
499 | (ovl_dentry_has_upper_alias(dentry) || disconnected) && | |
500 | !ovl_dentry_needs_data_copy_up_locked(dentry, flags)) | |
501 | return true; | |
502 | ||
503 | return false; | |
504 | } | |
505 | ||
506 | bool ovl_already_copied_up(struct dentry *dentry, int flags) | |
2002df85 VG |
507 | { |
508 | bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; | |
509 | ||
510 | /* | |
511 | * Check if copy-up has happened as well as for upper alias (in | |
512 | * case of hard links) is there. | |
513 | * | |
514 | * Both checks are lockless: | |
515 | * - false negatives: will recheck under oi->lock | |
516 | * - false positives: | |
517 | * + ovl_dentry_upper() uses memory barriers to ensure the | |
518 | * upper dentry is up-to-date | |
519 | * + ovl_dentry_has_upper_alias() relies on locking of | |
520 | * upper parent i_rwsem to prevent reordering copy-up | |
521 | * with rename. | |
522 | */ | |
523 | if (ovl_dentry_upper(dentry) && | |
0c288874 VG |
524 | (ovl_dentry_has_upper_alias(dentry) || disconnected) && |
525 | !ovl_dentry_needs_data_copy_up(dentry, flags)) | |
2002df85 VG |
526 | return true; |
527 | ||
528 | return false; | |
529 | } | |
530 | ||
0c288874 | 531 | int ovl_copy_up_start(struct dentry *dentry, int flags) |
39d3d60a | 532 | { |
1e92e307 | 533 | struct inode *inode = d_inode(dentry); |
39d3d60a AG |
534 | int err; |
535 | ||
531d3040 | 536 | err = ovl_inode_lock_interruptible(inode); |
0c288874 | 537 | if (!err && ovl_already_copied_up_locked(dentry, flags)) { |
a015dafc | 538 | err = 1; /* Already copied up */ |
1e92e307 | 539 | ovl_inode_unlock(inode); |
39d3d60a | 540 | } |
39d3d60a AG |
541 | |
542 | return err; | |
543 | } | |
544 | ||
545 | void ovl_copy_up_end(struct dentry *dentry) | |
546 | { | |
1e92e307 | 547 | ovl_inode_unlock(d_inode(dentry)); |
39d3d60a | 548 | } |
82b749b2 | 549 | |
610afc0b | 550 | bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry) |
b79e05aa AG |
551 | { |
552 | int res; | |
553 | ||
610afc0b | 554 | res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0); |
b79e05aa AG |
555 | |
556 | /* Zero size value means "copied up but origin unknown" */ | |
557 | if (res >= 0) | |
558 | return true; | |
559 | ||
560 | return false; | |
561 | } | |
562 | ||
610afc0b | 563 | bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, |
43d193f8 | 564 | enum ovl_xattr ox) |
f3a15685 AG |
565 | { |
566 | int res; | |
567 | char val; | |
568 | ||
569 | if (!d_is_dir(dentry)) | |
570 | return false; | |
571 | ||
43d193f8 | 572 | res = ovl_do_getxattr(OVL_FS(sb), dentry, ox, &val, 1); |
f3a15685 AG |
573 | if (res == 1 && val == 'y') |
574 | return true; | |
575 | ||
576 | return false; | |
577 | } | |
578 | ||
43d193f8 MS |
579 | #define OVL_XATTR_OPAQUE_POSTFIX "opaque" |
580 | #define OVL_XATTR_REDIRECT_POSTFIX "redirect" | |
581 | #define OVL_XATTR_ORIGIN_POSTFIX "origin" | |
582 | #define OVL_XATTR_IMPURE_POSTFIX "impure" | |
583 | #define OVL_XATTR_NLINK_POSTFIX "nlink" | |
584 | #define OVL_XATTR_UPPER_POSTFIX "upper" | |
585 | #define OVL_XATTR_METACOPY_POSTFIX "metacopy" | |
586 | ||
587 | #define OVL_XATTR_TAB_ENTRY(x) \ | |
2d2f2d73 MS |
588 | [x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \ |
589 | [true] = OVL_XATTR_USER_PREFIX x ## _POSTFIX } | |
43d193f8 | 590 | |
2d2f2d73 | 591 | const char *const ovl_xattr_table[][2] = { |
43d193f8 MS |
592 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE), |
593 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT), | |
594 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN), | |
595 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE), | |
596 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK), | |
597 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER), | |
598 | OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY), | |
599 | }; | |
600 | ||
82b749b2 | 601 | int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, |
43d193f8 | 602 | enum ovl_xattr ox, const void *value, size_t size, |
82b749b2 AG |
603 | int xerr) |
604 | { | |
605 | int err; | |
606 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
607 | ||
608 | if (ofs->noxattr) | |
609 | return xerr; | |
610 | ||
43d193f8 | 611 | err = ovl_do_setxattr(ofs, upperdentry, ox, value, size); |
82b749b2 AG |
612 | |
613 | if (err == -EOPNOTSUPP) { | |
43d193f8 | 614 | pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox)); |
82b749b2 AG |
615 | ofs->noxattr = true; |
616 | return xerr; | |
617 | } | |
618 | ||
619 | return err; | |
620 | } | |
f3a15685 AG |
621 | |
622 | int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) | |
623 | { | |
624 | int err; | |
f3a15685 | 625 | |
13c72075 | 626 | if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) |
f3a15685 AG |
627 | return 0; |
628 | ||
629 | /* | |
630 | * Do not fail when upper doesn't support xattrs. | |
631 | * Upper inodes won't have origin nor redirect xattr anyway. | |
632 | */ | |
633 | err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, | |
634 | "y", 1, 0); | |
635 | if (!err) | |
13c72075 | 636 | ovl_set_flag(OVL_IMPURE, d_inode(dentry)); |
f3a15685 AG |
637 | |
638 | return err; | |
639 | } | |
13c72075 MS |
640 | |
641 | void ovl_set_flag(unsigned long flag, struct inode *inode) | |
642 | { | |
643 | set_bit(flag, &OVL_I(inode)->flags); | |
644 | } | |
645 | ||
4edb83bb MS |
646 | void ovl_clear_flag(unsigned long flag, struct inode *inode) |
647 | { | |
648 | clear_bit(flag, &OVL_I(inode)->flags); | |
649 | } | |
650 | ||
13c72075 MS |
651 | bool ovl_test_flag(unsigned long flag, struct inode *inode) |
652 | { | |
653 | return test_bit(flag, &OVL_I(inode)->flags); | |
654 | } | |
ad0af710 AG |
655 | |
656 | /** | |
657 | * Caller must hold a reference to inode to prevent it from being freed while | |
658 | * it is marked inuse. | |
659 | */ | |
660 | bool ovl_inuse_trylock(struct dentry *dentry) | |
661 | { | |
662 | struct inode *inode = d_inode(dentry); | |
663 | bool locked = false; | |
664 | ||
665 | spin_lock(&inode->i_lock); | |
666 | if (!(inode->i_state & I_OVL_INUSE)) { | |
667 | inode->i_state |= I_OVL_INUSE; | |
668 | locked = true; | |
669 | } | |
670 | spin_unlock(&inode->i_lock); | |
671 | ||
672 | return locked; | |
673 | } | |
674 | ||
675 | void ovl_inuse_unlock(struct dentry *dentry) | |
676 | { | |
677 | if (dentry) { | |
678 | struct inode *inode = d_inode(dentry); | |
679 | ||
680 | spin_lock(&inode->i_lock); | |
681 | WARN_ON(!(inode->i_state & I_OVL_INUSE)); | |
682 | inode->i_state &= ~I_OVL_INUSE; | |
683 | spin_unlock(&inode->i_lock); | |
684 | } | |
685 | } | |
5f8415d6 | 686 | |
146d62e5 AG |
687 | bool ovl_is_inuse(struct dentry *dentry) |
688 | { | |
689 | struct inode *inode = d_inode(dentry); | |
690 | bool inuse; | |
691 | ||
692 | spin_lock(&inode->i_lock); | |
693 | inuse = (inode->i_state & I_OVL_INUSE); | |
694 | spin_unlock(&inode->i_lock); | |
695 | ||
696 | return inuse; | |
697 | } | |
698 | ||
24b33ee1 AG |
699 | /* |
700 | * Does this overlay dentry need to be indexed on copy up? | |
701 | */ | |
702 | bool ovl_need_index(struct dentry *dentry) | |
703 | { | |
704 | struct dentry *lower = ovl_dentry_lower(dentry); | |
705 | ||
706 | if (!lower || !ovl_indexdir(dentry->d_sb)) | |
707 | return false; | |
708 | ||
fbd2d207 | 709 | /* Index all files for NFS export and consistency verification */ |
016b720f | 710 | if (ovl_index_all(dentry->d_sb)) |
fbd2d207 AG |
711 | return true; |
712 | ||
24b33ee1 AG |
713 | /* Index only lower hardlinks on copy up */ |
714 | if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1) | |
715 | return true; | |
716 | ||
717 | return false; | |
718 | } | |
719 | ||
9f4ec904 | 720 | /* Caller must hold OVL_I(inode)->lock */ |
caf70cb2 AG |
721 | static void ovl_cleanup_index(struct dentry *dentry) |
722 | { | |
1cdb0cb6 | 723 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
e7dd0e71 AG |
724 | struct dentry *indexdir = ovl_indexdir(dentry->d_sb); |
725 | struct inode *dir = indexdir->d_inode; | |
caf70cb2 AG |
726 | struct dentry *lowerdentry = ovl_dentry_lower(dentry); |
727 | struct dentry *upperdentry = ovl_dentry_upper(dentry); | |
728 | struct dentry *index = NULL; | |
729 | struct inode *inode; | |
63e13252 | 730 | struct qstr name = { }; |
caf70cb2 AG |
731 | int err; |
732 | ||
1cdb0cb6 | 733 | err = ovl_get_index_name(ofs, lowerdentry, &name); |
caf70cb2 AG |
734 | if (err) |
735 | goto fail; | |
736 | ||
737 | inode = d_inode(upperdentry); | |
89a17556 | 738 | if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { |
1bd0a3ae | 739 | pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", |
caf70cb2 AG |
740 | upperdentry, inode->i_ino, inode->i_nlink); |
741 | /* | |
742 | * We either have a bug with persistent union nlink or a lower | |
743 | * hardlink was added while overlay is mounted. Adding a lower | |
744 | * hardlink and then unlinking all overlay hardlinks would drop | |
745 | * overlay nlink to zero before all upper inodes are unlinked. | |
746 | * As a safety measure, when that situation is detected, set | |
747 | * the overlay nlink to the index inode nlink minus one for the | |
748 | * index entry itself. | |
749 | */ | |
750 | set_nlink(d_inode(dentry), inode->i_nlink - 1); | |
751 | ovl_set_nlink_upper(dentry); | |
752 | goto out; | |
753 | } | |
754 | ||
755 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
e7dd0e71 | 756 | index = lookup_one_len(name.name, indexdir, name.len); |
caf70cb2 | 757 | err = PTR_ERR(index); |
e7dd0e71 | 758 | if (IS_ERR(index)) { |
9f4ec904 | 759 | index = NULL; |
e7dd0e71 AG |
760 | } else if (ovl_index_all(dentry->d_sb)) { |
761 | /* Whiteout orphan index to block future open by handle */ | |
c21c839b CX |
762 | err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb), |
763 | dir, index); | |
e7dd0e71 AG |
764 | } else { |
765 | /* Cleanup orphan index entries */ | |
766 | err = ovl_cleanup(dir, index); | |
767 | } | |
9f4ec904 | 768 | |
caf70cb2 AG |
769 | inode_unlock(dir); |
770 | if (err) | |
771 | goto fail; | |
772 | ||
773 | out: | |
63e13252 | 774 | kfree(name.name); |
caf70cb2 AG |
775 | dput(index); |
776 | return; | |
777 | ||
778 | fail: | |
1bd0a3ae | 779 | pr_err("cleanup index of '%pd2' failed (%i)\n", dentry, err); |
caf70cb2 AG |
780 | goto out; |
781 | } | |
782 | ||
5f8415d6 AG |
783 | /* |
784 | * Operations that change overlay inode and upper inode nlink need to be | |
785 | * synchronized with copy up for persistent nlink accounting. | |
786 | */ | |
0e32992f | 787 | int ovl_nlink_start(struct dentry *dentry) |
5f8415d6 | 788 | { |
1e92e307 | 789 | struct inode *inode = d_inode(dentry); |
5f8415d6 AG |
790 | const struct cred *old_cred; |
791 | int err; | |
792 | ||
1e92e307 | 793 | if (WARN_ON(!inode)) |
0e32992f | 794 | return -ENOENT; |
5f8415d6 AG |
795 | |
796 | /* | |
797 | * With inodes index is enabled, we store the union overlay nlink | |
24b33ee1 | 798 | * in an xattr on the index inode. When whiting out an indexed lower, |
5f8415d6 AG |
799 | * we need to decrement the overlay persistent nlink, but before the |
800 | * first copy up, we have no upper index inode to store the xattr. | |
801 | * | |
24b33ee1 | 802 | * As a workaround, before whiteout/rename over an indexed lower, |
5f8415d6 AG |
803 | * copy up to create the upper index. Creating the upper index will |
804 | * initialize the overlay nlink, so it could be dropped if unlink | |
805 | * or rename succeeds. | |
806 | * | |
807 | * TODO: implement metadata only index copy up when called with | |
808 | * ovl_copy_up_flags(dentry, O_PATH). | |
809 | */ | |
24b33ee1 | 810 | if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) { |
5f8415d6 AG |
811 | err = ovl_copy_up(dentry); |
812 | if (err) | |
813 | return err; | |
814 | } | |
815 | ||
531d3040 | 816 | err = ovl_inode_lock_interruptible(inode); |
5f8415d6 AG |
817 | if (err) |
818 | return err; | |
819 | ||
1e92e307 | 820 | if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode)) |
5f8415d6 AG |
821 | goto out; |
822 | ||
823 | old_cred = ovl_override_creds(dentry->d_sb); | |
824 | /* | |
825 | * The overlay inode nlink should be incremented/decremented IFF the | |
826 | * upper operation succeeds, along with nlink change of upper inode. | |
827 | * Therefore, before link/unlink/rename, we store the union nlink | |
828 | * value relative to the upper inode nlink in an upper inode xattr. | |
829 | */ | |
830 | err = ovl_set_nlink_upper(dentry); | |
831 | revert_creds(old_cred); | |
832 | ||
833 | out: | |
834 | if (err) | |
1e92e307 | 835 | ovl_inode_unlock(inode); |
5f8415d6 AG |
836 | |
837 | return err; | |
838 | } | |
839 | ||
0e32992f | 840 | void ovl_nlink_end(struct dentry *dentry) |
5f8415d6 | 841 | { |
1e92e307 AG |
842 | struct inode *inode = d_inode(dentry); |
843 | ||
844 | if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) { | |
0e32992f | 845 | const struct cred *old_cred; |
caf70cb2 | 846 | |
0e32992f AG |
847 | old_cred = ovl_override_creds(dentry->d_sb); |
848 | ovl_cleanup_index(dentry); | |
849 | revert_creds(old_cred); | |
caf70cb2 | 850 | } |
0e32992f | 851 | |
1e92e307 | 852 | ovl_inode_unlock(inode); |
5f8415d6 | 853 | } |
5820dc08 AG |
854 | |
855 | int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) | |
856 | { | |
857 | /* Workdir should not be the same as upperdir */ | |
858 | if (workdir == upperdir) | |
859 | goto err; | |
860 | ||
861 | /* Workdir should not be subdir of upperdir and vice versa */ | |
862 | if (lock_rename(workdir, upperdir) != NULL) | |
863 | goto err_unlock; | |
864 | ||
865 | return 0; | |
866 | ||
867 | err_unlock: | |
868 | unlock_rename(workdir, upperdir); | |
869 | err: | |
1bd0a3ae | 870 | pr_err("failed to lock workdir+upperdir\n"); |
5820dc08 AG |
871 | return -EIO; |
872 | } | |
9d3dfea3 VG |
873 | |
874 | /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ | |
610afc0b | 875 | int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry) |
9d3dfea3 VG |
876 | { |
877 | int res; | |
878 | ||
879 | /* Only regular files can have metacopy xattr */ | |
880 | if (!S_ISREG(d_inode(dentry)->i_mode)) | |
881 | return 0; | |
882 | ||
610afc0b | 883 | res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0); |
9d3dfea3 VG |
884 | if (res < 0) { |
885 | if (res == -ENODATA || res == -EOPNOTSUPP) | |
886 | return 0; | |
87b2c60c MS |
887 | /* |
888 | * getxattr on user.* may fail with EACCES in case there's no | |
889 | * read permission on the inode. Not much we can do, other than | |
890 | * tell the caller that this is not a metacopy inode. | |
891 | */ | |
892 | if (ofs->config.userxattr && res == -EACCES) | |
893 | return 0; | |
9d3dfea3 VG |
894 | goto out; |
895 | } | |
896 | ||
897 | return 1; | |
898 | out: | |
1bd0a3ae | 899 | pr_warn_ratelimited("failed to get metacopy (%i)\n", res); |
9d3dfea3 VG |
900 | return res; |
901 | } | |
67d756c2 VG |
902 | |
903 | bool ovl_is_metacopy_dentry(struct dentry *dentry) | |
904 | { | |
905 | struct ovl_entry *oe = dentry->d_fsdata; | |
906 | ||
907 | if (!d_is_reg(dentry)) | |
908 | return false; | |
909 | ||
910 | if (ovl_dentry_upper(dentry)) { | |
911 | if (!ovl_has_upperdata(d_inode(dentry))) | |
912 | return true; | |
913 | return false; | |
914 | } | |
915 | ||
916 | return (oe->numlower > 1); | |
917 | } | |
0a2d0d3f | 918 | |
610afc0b MS |
919 | char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, |
920 | int padding) | |
993a0b2a VG |
921 | { |
922 | int res; | |
923 | char *s, *next, *buf = NULL; | |
924 | ||
610afc0b | 925 | res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0); |
92f0d6c9 | 926 | if (res == -ENODATA || res == -EOPNOTSUPP) |
993a0b2a | 927 | return NULL; |
0a2d0d3f | 928 | if (res < 0) |
92f0d6c9 MS |
929 | goto fail; |
930 | if (res == 0) | |
931 | goto invalid; | |
932 | ||
933 | buf = kzalloc(res + padding + 1, GFP_KERNEL); | |
934 | if (!buf) | |
935 | return ERR_PTR(-ENOMEM); | |
936 | ||
610afc0b | 937 | res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res); |
92f0d6c9 MS |
938 | if (res < 0) |
939 | goto fail; | |
0a2d0d3f VG |
940 | if (res == 0) |
941 | goto invalid; | |
942 | ||
943 | if (buf[0] == '/') { | |
944 | for (s = buf; *s++ == '/'; s = next) { | |
945 | next = strchrnul(s, '/'); | |
946 | if (s == next) | |
947 | goto invalid; | |
948 | } | |
949 | } else { | |
950 | if (strchr(buf, '/') != NULL) | |
951 | goto invalid; | |
952 | } | |
953 | ||
954 | return buf; | |
0a2d0d3f | 955 | invalid: |
1bd0a3ae | 956 | pr_warn_ratelimited("invalid redirect (%s)\n", buf); |
0a2d0d3f | 957 | res = -EINVAL; |
92f0d6c9 MS |
958 | goto err_free; |
959 | fail: | |
960 | pr_warn_ratelimited("failed to get redirect (%i)\n", res); | |
961 | err_free: | |
993a0b2a VG |
962 | kfree(buf); |
963 | return ERR_PTR(res); | |
0a2d0d3f | 964 | } |
335d3fc5 SD |
965 | |
966 | /* | |
967 | * ovl_sync_status() - Check fs sync status for volatile mounts | |
968 | * | |
969 | * Returns 1 if this is not a volatile mount and a real sync is required. | |
970 | * | |
971 | * Returns 0 if syncing can be skipped because mount is volatile, and no errors | |
972 | * have occurred on the upperdir since the mount. | |
973 | * | |
974 | * Returns -errno if it is a volatile mount, and the error that occurred since | |
975 | * the last mount. If the error code changes, it'll return the latest error | |
976 | * code. | |
977 | */ | |
978 | ||
979 | int ovl_sync_status(struct ovl_fs *ofs) | |
980 | { | |
981 | struct vfsmount *mnt; | |
982 | ||
983 | if (ovl_should_sync(ofs)) | |
984 | return 1; | |
985 | ||
986 | mnt = ovl_upper_mnt(ofs); | |
987 | if (!mnt) | |
988 | return 0; | |
989 | ||
990 | return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq); | |
991 | } |