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Commit | Line | Data |
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bbb1e54d MS |
1 | /* |
2 | * Copyright (C) 2011 Novell Inc. | |
3 | * Copyright (C) 2016 Red Hat, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/fs.h> | |
11 | #include <linux/mount.h> | |
12 | #include <linux/slab.h> | |
5b825c3a | 13 | #include <linux/cred.h> |
bbb1e54d | 14 | #include <linux/xattr.h> |
02bcd157 AG |
15 | #include <linux/exportfs.h> |
16 | #include <linux/uuid.h> | |
caf70cb2 AG |
17 | #include <linux/namei.h> |
18 | #include <linux/ratelimit.h> | |
bbb1e54d | 19 | #include "overlayfs.h" |
bbb1e54d MS |
20 | |
21 | int ovl_want_write(struct dentry *dentry) | |
22 | { | |
23 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
24 | return mnt_want_write(ofs->upper_mnt); | |
25 | } | |
26 | ||
27 | void ovl_drop_write(struct dentry *dentry) | |
28 | { | |
29 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
30 | mnt_drop_write(ofs->upper_mnt); | |
31 | } | |
32 | ||
33 | struct dentry *ovl_workdir(struct dentry *dentry) | |
34 | { | |
35 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
36 | return ofs->workdir; | |
37 | } | |
38 | ||
39 | const struct cred *ovl_override_creds(struct super_block *sb) | |
40 | { | |
41 | struct ovl_fs *ofs = sb->s_fs_info; | |
42 | ||
43 | return override_creds(ofs->creator_cred); | |
44 | } | |
45 | ||
7bcd74b9 AG |
46 | struct super_block *ovl_same_sb(struct super_block *sb) |
47 | { | |
48 | struct ovl_fs *ofs = sb->s_fs_info; | |
49 | ||
5148626b AG |
50 | if (!ofs->numlowerfs) |
51 | return ofs->upper_mnt->mnt_sb; | |
52 | else if (ofs->numlowerfs == 1 && !ofs->upper_mnt) | |
53 | return ofs->lower_fs[0].sb; | |
54 | else | |
55 | return NULL; | |
7bcd74b9 AG |
56 | } |
57 | ||
e487d889 AG |
58 | /* |
59 | * Check if underlying fs supports file handles and try to determine encoding | |
60 | * type, in order to deduce maximum inode number used by fs. | |
61 | * | |
62 | * Return 0 if file handles are not supported. | |
63 | * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding. | |
64 | * Return -1 if fs uses a non default encoding with unknown inode size. | |
65 | */ | |
66 | int ovl_can_decode_fh(struct super_block *sb) | |
02bcd157 | 67 | { |
e487d889 AG |
68 | if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry || |
69 | uuid_is_null(&sb->s_uuid)) | |
70 | return 0; | |
71 | ||
72 | return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; | |
02bcd157 AG |
73 | } |
74 | ||
75 | struct dentry *ovl_indexdir(struct super_block *sb) | |
76 | { | |
77 | struct ovl_fs *ofs = sb->s_fs_info; | |
78 | ||
79 | return ofs->indexdir; | |
80 | } | |
81 | ||
f168f109 AG |
82 | /* Index all files on copy up. For now only enabled for NFS export */ |
83 | bool ovl_index_all(struct super_block *sb) | |
84 | { | |
85 | struct ovl_fs *ofs = sb->s_fs_info; | |
86 | ||
87 | return ofs->config.nfs_export && ofs->config.index; | |
88 | } | |
89 | ||
90 | /* Verify lower origin on lookup. For now only enabled for NFS export */ | |
91 | bool ovl_verify_lower(struct super_block *sb) | |
92 | { | |
93 | struct ovl_fs *ofs = sb->s_fs_info; | |
94 | ||
95 | return ofs->config.nfs_export && ofs->config.index; | |
96 | } | |
97 | ||
bbb1e54d MS |
98 | struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
99 | { | |
100 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); | |
101 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
102 | ||
103 | if (oe) | |
104 | oe->numlower = numlower; | |
105 | ||
106 | return oe; | |
107 | } | |
108 | ||
109 | bool ovl_dentry_remote(struct dentry *dentry) | |
110 | { | |
111 | return dentry->d_flags & | |
112 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | | |
113 | DCACHE_OP_REAL); | |
114 | } | |
115 | ||
116 | bool ovl_dentry_weird(struct dentry *dentry) | |
117 | { | |
118 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
119 | DCACHE_MANAGE_TRANSIT | | |
120 | DCACHE_OP_HASH | | |
121 | DCACHE_OP_COMPARE); | |
122 | } | |
123 | ||
124 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
125 | { | |
126 | struct ovl_entry *oe = dentry->d_fsdata; | |
127 | enum ovl_path_type type = 0; | |
128 | ||
09d8b586 | 129 | if (ovl_dentry_upper(dentry)) { |
bbb1e54d MS |
130 | type = __OVL_PATH_UPPER; |
131 | ||
132 | /* | |
59548503 | 133 | * Non-dir dentry can hold lower dentry of its copy up origin. |
bbb1e54d | 134 | */ |
59548503 AG |
135 | if (oe->numlower) { |
136 | type |= __OVL_PATH_ORIGIN; | |
137 | if (d_is_dir(dentry)) | |
138 | type |= __OVL_PATH_MERGE; | |
139 | } | |
bbb1e54d MS |
140 | } else { |
141 | if (oe->numlower > 1) | |
142 | type |= __OVL_PATH_MERGE; | |
143 | } | |
144 | return type; | |
145 | } | |
146 | ||
147 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
148 | { | |
149 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
bbb1e54d MS |
150 | |
151 | path->mnt = ofs->upper_mnt; | |
09d8b586 | 152 | path->dentry = ovl_dentry_upper(dentry); |
bbb1e54d MS |
153 | } |
154 | ||
155 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
156 | { | |
157 | struct ovl_entry *oe = dentry->d_fsdata; | |
158 | ||
b9343632 CR |
159 | if (oe->numlower) { |
160 | path->mnt = oe->lowerstack[0].layer->mnt; | |
161 | path->dentry = oe->lowerstack[0].dentry; | |
162 | } else { | |
163 | *path = (struct path) { }; | |
164 | } | |
bbb1e54d MS |
165 | } |
166 | ||
167 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
168 | { | |
169 | enum ovl_path_type type = ovl_path_type(dentry); | |
170 | ||
171 | if (!OVL_TYPE_UPPER(type)) | |
172 | ovl_path_lower(dentry, path); | |
173 | else | |
174 | ovl_path_upper(dentry, path); | |
175 | ||
176 | return type; | |
177 | } | |
178 | ||
179 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
180 | { | |
09d8b586 | 181 | return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); |
bbb1e54d MS |
182 | } |
183 | ||
184 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
185 | { | |
186 | struct ovl_entry *oe = dentry->d_fsdata; | |
187 | ||
09d8b586 | 188 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; |
bbb1e54d MS |
189 | } |
190 | ||
da309e8c AG |
191 | struct ovl_layer *ovl_layer_lower(struct dentry *dentry) |
192 | { | |
193 | struct ovl_entry *oe = dentry->d_fsdata; | |
194 | ||
195 | return oe->numlower ? oe->lowerstack[0].layer : NULL; | |
196 | } | |
197 | ||
bbb1e54d MS |
198 | struct dentry *ovl_dentry_real(struct dentry *dentry) |
199 | { | |
09d8b586 | 200 | return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); |
bbb1e54d MS |
201 | } |
202 | ||
1d88f183 MS |
203 | struct dentry *ovl_i_dentry_upper(struct inode *inode) |
204 | { | |
205 | return ovl_upperdentry_dereference(OVL_I(inode)); | |
206 | } | |
207 | ||
09d8b586 | 208 | struct inode *ovl_inode_upper(struct inode *inode) |
25b7713a | 209 | { |
1d88f183 | 210 | struct dentry *upperdentry = ovl_i_dentry_upper(inode); |
25b7713a | 211 | |
09d8b586 MS |
212 | return upperdentry ? d_inode(upperdentry) : NULL; |
213 | } | |
25b7713a | 214 | |
09d8b586 MS |
215 | struct inode *ovl_inode_lower(struct inode *inode) |
216 | { | |
217 | return OVL_I(inode)->lower; | |
218 | } | |
25b7713a | 219 | |
09d8b586 MS |
220 | struct inode *ovl_inode_real(struct inode *inode) |
221 | { | |
222 | return ovl_inode_upper(inode) ?: ovl_inode_lower(inode); | |
25b7713a MS |
223 | } |
224 | ||
09d8b586 | 225 | |
4edb83bb | 226 | struct ovl_dir_cache *ovl_dir_cache(struct inode *inode) |
bbb1e54d | 227 | { |
4edb83bb | 228 | return OVL_I(inode)->cache; |
bbb1e54d MS |
229 | } |
230 | ||
4edb83bb | 231 | void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) |
bbb1e54d | 232 | { |
4edb83bb | 233 | OVL_I(inode)->cache = cache; |
bbb1e54d MS |
234 | } |
235 | ||
c62520a8 AG |
236 | void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry) |
237 | { | |
238 | set_bit(flag, &OVL_E(dentry)->flags); | |
239 | } | |
240 | ||
241 | void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry) | |
242 | { | |
243 | clear_bit(flag, &OVL_E(dentry)->flags); | |
244 | } | |
245 | ||
246 | bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry) | |
247 | { | |
248 | return test_bit(flag, &OVL_E(dentry)->flags); | |
249 | } | |
250 | ||
bbb1e54d MS |
251 | bool ovl_dentry_is_opaque(struct dentry *dentry) |
252 | { | |
c62520a8 | 253 | return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry); |
bbb1e54d MS |
254 | } |
255 | ||
256 | bool ovl_dentry_is_whiteout(struct dentry *dentry) | |
257 | { | |
258 | return !dentry->d_inode && ovl_dentry_is_opaque(dentry); | |
259 | } | |
260 | ||
5cf5b477 | 261 | void ovl_dentry_set_opaque(struct dentry *dentry) |
bbb1e54d | 262 | { |
c62520a8 | 263 | ovl_dentry_set_flag(OVL_E_OPAQUE, dentry); |
bbb1e54d MS |
264 | } |
265 | ||
55acc661 | 266 | /* |
aa3ff3c1 AG |
267 | * For hard links and decoded file handles, it's possible for ovl_dentry_upper() |
268 | * to return positive, while there's no actual upper alias for the inode. | |
269 | * Copy up code needs to know about the existence of the upper alias, so it | |
270 | * can't use ovl_dentry_upper(). | |
55acc661 MS |
271 | */ |
272 | bool ovl_dentry_has_upper_alias(struct dentry *dentry) | |
273 | { | |
c62520a8 | 274 | return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry); |
55acc661 MS |
275 | } |
276 | ||
277 | void ovl_dentry_set_upper_alias(struct dentry *dentry) | |
278 | { | |
c62520a8 | 279 | ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry); |
55acc661 MS |
280 | } |
281 | ||
0c288874 VG |
282 | static bool ovl_should_check_upperdata(struct inode *inode) |
283 | { | |
284 | if (!S_ISREG(inode->i_mode)) | |
285 | return false; | |
286 | ||
287 | if (!ovl_inode_lower(inode)) | |
288 | return false; | |
289 | ||
290 | return true; | |
291 | } | |
292 | ||
293 | bool ovl_has_upperdata(struct inode *inode) | |
294 | { | |
295 | if (!ovl_should_check_upperdata(inode)) | |
296 | return true; | |
297 | ||
298 | if (!ovl_test_flag(OVL_UPPERDATA, inode)) | |
299 | return false; | |
300 | /* | |
301 | * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of | |
302 | * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure | |
303 | * if setting of OVL_UPPERDATA is visible, then effects of writes | |
304 | * before that are visible too. | |
305 | */ | |
306 | smp_rmb(); | |
307 | return true; | |
308 | } | |
309 | ||
310 | void ovl_set_upperdata(struct inode *inode) | |
311 | { | |
312 | /* | |
313 | * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure | |
314 | * if OVL_UPPERDATA flag is visible, then effects of write operations | |
315 | * before it are visible as well. | |
316 | */ | |
317 | smp_wmb(); | |
318 | ovl_set_flag(OVL_UPPERDATA, inode); | |
319 | } | |
320 | ||
321 | /* Caller should hold ovl_inode->lock */ | |
322 | bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags) | |
323 | { | |
324 | if (!ovl_open_flags_need_copy_up(flags)) | |
325 | return false; | |
326 | ||
327 | return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry)); | |
328 | } | |
329 | ||
330 | bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) | |
331 | { | |
332 | if (!ovl_open_flags_need_copy_up(flags)) | |
333 | return false; | |
334 | ||
335 | return !ovl_has_upperdata(d_inode(dentry)); | |
336 | } | |
337 | ||
a6c60655 MS |
338 | bool ovl_redirect_dir(struct super_block *sb) |
339 | { | |
340 | struct ovl_fs *ofs = sb->s_fs_info; | |
341 | ||
21a22878 | 342 | return ofs->config.redirect_dir && !ofs->noxattr; |
a6c60655 MS |
343 | } |
344 | ||
345 | const char *ovl_dentry_get_redirect(struct dentry *dentry) | |
346 | { | |
cf31c463 | 347 | return OVL_I(d_inode(dentry))->redirect; |
a6c60655 MS |
348 | } |
349 | ||
350 | void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) | |
351 | { | |
cf31c463 | 352 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); |
a6c60655 | 353 | |
cf31c463 MS |
354 | kfree(oi->redirect); |
355 | oi->redirect = redirect; | |
a6c60655 MS |
356 | } |
357 | ||
09d8b586 MS |
358 | void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, |
359 | struct dentry *lowerdentry) | |
bbb1e54d | 360 | { |
695b46e7 AG |
361 | struct inode *realinode = d_inode(upperdentry ?: lowerdentry); |
362 | ||
09d8b586 MS |
363 | if (upperdentry) |
364 | OVL_I(inode)->__upperdentry = upperdentry; | |
365 | if (lowerdentry) | |
31747eda | 366 | OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); |
bbb1e54d | 367 | |
695b46e7 | 368 | ovl_copyattr(realinode, inode); |
4f357295 | 369 | ovl_copyflags(realinode, inode); |
695b46e7 AG |
370 | if (!inode->i_ino) |
371 | inode->i_ino = realinode->i_ino; | |
bbb1e54d MS |
372 | } |
373 | ||
09d8b586 | 374 | void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) |
bbb1e54d | 375 | { |
09d8b586 | 376 | struct inode *upperinode = d_inode(upperdentry); |
e6d2ebdd | 377 | |
09d8b586 MS |
378 | WARN_ON(OVL_I(inode)->__upperdentry); |
379 | ||
25b7713a | 380 | /* |
09d8b586 | 381 | * Make sure upperdentry is consistent before making it visible |
25b7713a MS |
382 | */ |
383 | smp_wmb(); | |
09d8b586 | 384 | OVL_I(inode)->__upperdentry = upperdentry; |
31747eda | 385 | if (inode_unhashed(inode)) { |
695b46e7 AG |
386 | if (!inode->i_ino) |
387 | inode->i_ino = upperinode->i_ino; | |
25b7713a | 388 | inode->i_private = upperinode; |
bbb1e54d | 389 | __insert_inode_hash(inode, (unsigned long) upperinode); |
25b7713a | 390 | } |
bbb1e54d MS |
391 | } |
392 | ||
d9854c87 | 393 | static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) |
bbb1e54d | 394 | { |
04a01ac7 | 395 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 396 | |
04a01ac7 | 397 | WARN_ON(!inode_is_locked(inode)); |
4edb83bb MS |
398 | /* |
399 | * Version is used by readdir code to keep cache consistent. For merge | |
400 | * dirs all changes need to be noted. For non-merge dirs, cache only | |
401 | * contains impure (ones which have been copied up and have origins) | |
402 | * entries, so only need to note changes to impure entries. | |
403 | */ | |
404 | if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) | |
405 | OVL_I(inode)->version++; | |
bbb1e54d MS |
406 | } |
407 | ||
d9854c87 MS |
408 | void ovl_dir_modified(struct dentry *dentry, bool impurity) |
409 | { | |
410 | /* Copy mtime/ctime */ | |
411 | ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); | |
412 | ||
413 | ovl_dentry_version_inc(dentry, impurity); | |
414 | } | |
415 | ||
bbb1e54d MS |
416 | u64 ovl_dentry_version_get(struct dentry *dentry) |
417 | { | |
04a01ac7 | 418 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 419 | |
04a01ac7 MS |
420 | WARN_ON(!inode_is_locked(inode)); |
421 | return OVL_I(inode)->version; | |
bbb1e54d MS |
422 | } |
423 | ||
424 | bool ovl_is_whiteout(struct dentry *dentry) | |
425 | { | |
426 | struct inode *inode = dentry->d_inode; | |
427 | ||
428 | return inode && IS_WHITEOUT(inode); | |
429 | } | |
430 | ||
431 | struct file *ovl_path_open(struct path *path, int flags) | |
432 | { | |
433 | return dentry_open(path, flags | O_NOATIME, current_cred()); | |
434 | } | |
39d3d60a | 435 | |
0c288874 VG |
436 | /* Caller should hold ovl_inode->lock */ |
437 | static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags) | |
438 | { | |
439 | bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; | |
440 | ||
441 | if (ovl_dentry_upper(dentry) && | |
442 | (ovl_dentry_has_upper_alias(dentry) || disconnected) && | |
443 | !ovl_dentry_needs_data_copy_up_locked(dentry, flags)) | |
444 | return true; | |
445 | ||
446 | return false; | |
447 | } | |
448 | ||
449 | bool ovl_already_copied_up(struct dentry *dentry, int flags) | |
2002df85 VG |
450 | { |
451 | bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; | |
452 | ||
453 | /* | |
454 | * Check if copy-up has happened as well as for upper alias (in | |
455 | * case of hard links) is there. | |
456 | * | |
457 | * Both checks are lockless: | |
458 | * - false negatives: will recheck under oi->lock | |
459 | * - false positives: | |
460 | * + ovl_dentry_upper() uses memory barriers to ensure the | |
461 | * upper dentry is up-to-date | |
462 | * + ovl_dentry_has_upper_alias() relies on locking of | |
463 | * upper parent i_rwsem to prevent reordering copy-up | |
464 | * with rename. | |
465 | */ | |
466 | if (ovl_dentry_upper(dentry) && | |
0c288874 VG |
467 | (ovl_dentry_has_upper_alias(dentry) || disconnected) && |
468 | !ovl_dentry_needs_data_copy_up(dentry, flags)) | |
2002df85 VG |
469 | return true; |
470 | ||
471 | return false; | |
472 | } | |
473 | ||
0c288874 | 474 | int ovl_copy_up_start(struct dentry *dentry, int flags) |
39d3d60a | 475 | { |
a015dafc | 476 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); |
39d3d60a AG |
477 | int err; |
478 | ||
a015dafc | 479 | err = mutex_lock_interruptible(&oi->lock); |
0c288874 | 480 | if (!err && ovl_already_copied_up_locked(dentry, flags)) { |
a015dafc AG |
481 | err = 1; /* Already copied up */ |
482 | mutex_unlock(&oi->lock); | |
39d3d60a | 483 | } |
39d3d60a AG |
484 | |
485 | return err; | |
486 | } | |
487 | ||
488 | void ovl_copy_up_end(struct dentry *dentry) | |
489 | { | |
a015dafc | 490 | mutex_unlock(&OVL_I(d_inode(dentry))->lock); |
39d3d60a | 491 | } |
82b749b2 | 492 | |
b79e05aa AG |
493 | bool ovl_check_origin_xattr(struct dentry *dentry) |
494 | { | |
495 | int res; | |
496 | ||
497 | res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); | |
498 | ||
499 | /* Zero size value means "copied up but origin unknown" */ | |
500 | if (res >= 0) | |
501 | return true; | |
502 | ||
503 | return false; | |
504 | } | |
505 | ||
f3a15685 AG |
506 | bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) |
507 | { | |
508 | int res; | |
509 | char val; | |
510 | ||
511 | if (!d_is_dir(dentry)) | |
512 | return false; | |
513 | ||
514 | res = vfs_getxattr(dentry, name, &val, 1); | |
515 | if (res == 1 && val == 'y') | |
516 | return true; | |
517 | ||
518 | return false; | |
519 | } | |
520 | ||
82b749b2 AG |
521 | int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, |
522 | const char *name, const void *value, size_t size, | |
523 | int xerr) | |
524 | { | |
525 | int err; | |
526 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
527 | ||
528 | if (ofs->noxattr) | |
529 | return xerr; | |
530 | ||
531 | err = ovl_do_setxattr(upperdentry, name, value, size, 0); | |
532 | ||
533 | if (err == -EOPNOTSUPP) { | |
534 | pr_warn("overlayfs: cannot set %s xattr on upper\n", name); | |
535 | ofs->noxattr = true; | |
536 | return xerr; | |
537 | } | |
538 | ||
539 | return err; | |
540 | } | |
f3a15685 AG |
541 | |
542 | int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) | |
543 | { | |
544 | int err; | |
f3a15685 | 545 | |
13c72075 | 546 | if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) |
f3a15685 AG |
547 | return 0; |
548 | ||
549 | /* | |
550 | * Do not fail when upper doesn't support xattrs. | |
551 | * Upper inodes won't have origin nor redirect xattr anyway. | |
552 | */ | |
553 | err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, | |
554 | "y", 1, 0); | |
555 | if (!err) | |
13c72075 | 556 | ovl_set_flag(OVL_IMPURE, d_inode(dentry)); |
f3a15685 AG |
557 | |
558 | return err; | |
559 | } | |
13c72075 MS |
560 | |
561 | void ovl_set_flag(unsigned long flag, struct inode *inode) | |
562 | { | |
563 | set_bit(flag, &OVL_I(inode)->flags); | |
564 | } | |
565 | ||
4edb83bb MS |
566 | void ovl_clear_flag(unsigned long flag, struct inode *inode) |
567 | { | |
568 | clear_bit(flag, &OVL_I(inode)->flags); | |
569 | } | |
570 | ||
13c72075 MS |
571 | bool ovl_test_flag(unsigned long flag, struct inode *inode) |
572 | { | |
573 | return test_bit(flag, &OVL_I(inode)->flags); | |
574 | } | |
ad0af710 AG |
575 | |
576 | /** | |
577 | * Caller must hold a reference to inode to prevent it from being freed while | |
578 | * it is marked inuse. | |
579 | */ | |
580 | bool ovl_inuse_trylock(struct dentry *dentry) | |
581 | { | |
582 | struct inode *inode = d_inode(dentry); | |
583 | bool locked = false; | |
584 | ||
585 | spin_lock(&inode->i_lock); | |
586 | if (!(inode->i_state & I_OVL_INUSE)) { | |
587 | inode->i_state |= I_OVL_INUSE; | |
588 | locked = true; | |
589 | } | |
590 | spin_unlock(&inode->i_lock); | |
591 | ||
592 | return locked; | |
593 | } | |
594 | ||
595 | void ovl_inuse_unlock(struct dentry *dentry) | |
596 | { | |
597 | if (dentry) { | |
598 | struct inode *inode = d_inode(dentry); | |
599 | ||
600 | spin_lock(&inode->i_lock); | |
601 | WARN_ON(!(inode->i_state & I_OVL_INUSE)); | |
602 | inode->i_state &= ~I_OVL_INUSE; | |
603 | spin_unlock(&inode->i_lock); | |
604 | } | |
605 | } | |
5f8415d6 | 606 | |
24b33ee1 AG |
607 | /* |
608 | * Does this overlay dentry need to be indexed on copy up? | |
609 | */ | |
610 | bool ovl_need_index(struct dentry *dentry) | |
611 | { | |
612 | struct dentry *lower = ovl_dentry_lower(dentry); | |
613 | ||
614 | if (!lower || !ovl_indexdir(dentry->d_sb)) | |
615 | return false; | |
616 | ||
fbd2d207 | 617 | /* Index all files for NFS export and consistency verification */ |
016b720f | 618 | if (ovl_index_all(dentry->d_sb)) |
fbd2d207 AG |
619 | return true; |
620 | ||
24b33ee1 AG |
621 | /* Index only lower hardlinks on copy up */ |
622 | if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1) | |
623 | return true; | |
624 | ||
625 | return false; | |
626 | } | |
627 | ||
9f4ec904 | 628 | /* Caller must hold OVL_I(inode)->lock */ |
caf70cb2 AG |
629 | static void ovl_cleanup_index(struct dentry *dentry) |
630 | { | |
e7dd0e71 AG |
631 | struct dentry *indexdir = ovl_indexdir(dentry->d_sb); |
632 | struct inode *dir = indexdir->d_inode; | |
caf70cb2 AG |
633 | struct dentry *lowerdentry = ovl_dentry_lower(dentry); |
634 | struct dentry *upperdentry = ovl_dentry_upper(dentry); | |
635 | struct dentry *index = NULL; | |
636 | struct inode *inode; | |
637 | struct qstr name; | |
638 | int err; | |
639 | ||
640 | err = ovl_get_index_name(lowerdentry, &name); | |
641 | if (err) | |
642 | goto fail; | |
643 | ||
644 | inode = d_inode(upperdentry); | |
89a17556 | 645 | if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { |
caf70cb2 AG |
646 | pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", |
647 | upperdentry, inode->i_ino, inode->i_nlink); | |
648 | /* | |
649 | * We either have a bug with persistent union nlink or a lower | |
650 | * hardlink was added while overlay is mounted. Adding a lower | |
651 | * hardlink and then unlinking all overlay hardlinks would drop | |
652 | * overlay nlink to zero before all upper inodes are unlinked. | |
653 | * As a safety measure, when that situation is detected, set | |
654 | * the overlay nlink to the index inode nlink minus one for the | |
655 | * index entry itself. | |
656 | */ | |
657 | set_nlink(d_inode(dentry), inode->i_nlink - 1); | |
658 | ovl_set_nlink_upper(dentry); | |
659 | goto out; | |
660 | } | |
661 | ||
662 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
e7dd0e71 | 663 | index = lookup_one_len(name.name, indexdir, name.len); |
caf70cb2 | 664 | err = PTR_ERR(index); |
e7dd0e71 | 665 | if (IS_ERR(index)) { |
9f4ec904 | 666 | index = NULL; |
e7dd0e71 AG |
667 | } else if (ovl_index_all(dentry->d_sb)) { |
668 | /* Whiteout orphan index to block future open by handle */ | |
669 | err = ovl_cleanup_and_whiteout(indexdir, dir, index); | |
670 | } else { | |
671 | /* Cleanup orphan index entries */ | |
672 | err = ovl_cleanup(dir, index); | |
673 | } | |
9f4ec904 | 674 | |
caf70cb2 AG |
675 | inode_unlock(dir); |
676 | if (err) | |
677 | goto fail; | |
678 | ||
679 | out: | |
680 | dput(index); | |
681 | return; | |
682 | ||
683 | fail: | |
684 | pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err); | |
685 | goto out; | |
686 | } | |
687 | ||
5f8415d6 AG |
688 | /* |
689 | * Operations that change overlay inode and upper inode nlink need to be | |
690 | * synchronized with copy up for persistent nlink accounting. | |
691 | */ | |
692 | int ovl_nlink_start(struct dentry *dentry, bool *locked) | |
693 | { | |
694 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); | |
695 | const struct cred *old_cred; | |
696 | int err; | |
697 | ||
89a17556 | 698 | if (!d_inode(dentry)) |
5f8415d6 AG |
699 | return 0; |
700 | ||
701 | /* | |
702 | * With inodes index is enabled, we store the union overlay nlink | |
24b33ee1 | 703 | * in an xattr on the index inode. When whiting out an indexed lower, |
5f8415d6 AG |
704 | * we need to decrement the overlay persistent nlink, but before the |
705 | * first copy up, we have no upper index inode to store the xattr. | |
706 | * | |
24b33ee1 | 707 | * As a workaround, before whiteout/rename over an indexed lower, |
5f8415d6 AG |
708 | * copy up to create the upper index. Creating the upper index will |
709 | * initialize the overlay nlink, so it could be dropped if unlink | |
710 | * or rename succeeds. | |
711 | * | |
712 | * TODO: implement metadata only index copy up when called with | |
713 | * ovl_copy_up_flags(dentry, O_PATH). | |
714 | */ | |
24b33ee1 | 715 | if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) { |
5f8415d6 AG |
716 | err = ovl_copy_up(dentry); |
717 | if (err) | |
718 | return err; | |
719 | } | |
720 | ||
721 | err = mutex_lock_interruptible(&oi->lock); | |
722 | if (err) | |
723 | return err; | |
724 | ||
89a17556 | 725 | if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry))) |
5f8415d6 AG |
726 | goto out; |
727 | ||
728 | old_cred = ovl_override_creds(dentry->d_sb); | |
729 | /* | |
730 | * The overlay inode nlink should be incremented/decremented IFF the | |
731 | * upper operation succeeds, along with nlink change of upper inode. | |
732 | * Therefore, before link/unlink/rename, we store the union nlink | |
733 | * value relative to the upper inode nlink in an upper inode xattr. | |
734 | */ | |
735 | err = ovl_set_nlink_upper(dentry); | |
736 | revert_creds(old_cred); | |
737 | ||
738 | out: | |
739 | if (err) | |
740 | mutex_unlock(&oi->lock); | |
741 | else | |
742 | *locked = true; | |
743 | ||
744 | return err; | |
745 | } | |
746 | ||
747 | void ovl_nlink_end(struct dentry *dentry, bool locked) | |
748 | { | |
caf70cb2 AG |
749 | if (locked) { |
750 | if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) && | |
751 | d_inode(dentry)->i_nlink == 0) { | |
752 | const struct cred *old_cred; | |
753 | ||
754 | old_cred = ovl_override_creds(dentry->d_sb); | |
755 | ovl_cleanup_index(dentry); | |
756 | revert_creds(old_cred); | |
757 | } | |
758 | ||
5f8415d6 | 759 | mutex_unlock(&OVL_I(d_inode(dentry))->lock); |
caf70cb2 | 760 | } |
5f8415d6 | 761 | } |
5820dc08 AG |
762 | |
763 | int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) | |
764 | { | |
765 | /* Workdir should not be the same as upperdir */ | |
766 | if (workdir == upperdir) | |
767 | goto err; | |
768 | ||
769 | /* Workdir should not be subdir of upperdir and vice versa */ | |
770 | if (lock_rename(workdir, upperdir) != NULL) | |
771 | goto err_unlock; | |
772 | ||
773 | return 0; | |
774 | ||
775 | err_unlock: | |
776 | unlock_rename(workdir, upperdir); | |
777 | err: | |
778 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
779 | return -EIO; | |
780 | } |