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1 | /* | |
2 | * | |
3 | * Copyright (C) 2011 Novell Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/file.h> | |
14 | #include <linux/splice.h> | |
15 | #include <linux/xattr.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/uaccess.h> | |
18 | #include <linux/sched/signal.h> | |
19 | #include <linux/cred.h> | |
20 | #include <linux/namei.h> | |
21 | #include <linux/fdtable.h> | |
22 | #include <linux/ratelimit.h> | |
23 | #include <linux/exportfs.h> | |
24 | #include "overlayfs.h" | |
25 | ||
26 | #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) | |
27 | ||
28 | static int ovl_ccup_set(const char *buf, const struct kernel_param *param) | |
29 | { | |
30 | pr_warn("overlayfs: \"check_copy_up\" module option is obsolete\n"); | |
31 | return 0; | |
32 | } | |
33 | ||
34 | static int ovl_ccup_get(char *buf, const struct kernel_param *param) | |
35 | { | |
36 | return sprintf(buf, "N\n"); | |
37 | } | |
38 | ||
39 | module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644); | |
40 | MODULE_PARM_DESC(ovl_check_copy_up, "Obsolete; does nothing"); | |
41 | ||
42 | int ovl_copy_xattr(struct dentry *old, struct dentry *new) | |
43 | { | |
44 | ssize_t list_size, size, value_size = 0; | |
45 | char *buf, *name, *value = NULL; | |
46 | int uninitialized_var(error); | |
47 | size_t slen; | |
48 | ||
49 | if (!(old->d_inode->i_opflags & IOP_XATTR) || | |
50 | !(new->d_inode->i_opflags & IOP_XATTR)) | |
51 | return 0; | |
52 | ||
53 | list_size = vfs_listxattr(old, NULL, 0); | |
54 | if (list_size <= 0) { | |
55 | if (list_size == -EOPNOTSUPP) | |
56 | return 0; | |
57 | return list_size; | |
58 | } | |
59 | ||
60 | buf = kzalloc(list_size, GFP_KERNEL); | |
61 | if (!buf) | |
62 | return -ENOMEM; | |
63 | ||
64 | list_size = vfs_listxattr(old, buf, list_size); | |
65 | if (list_size <= 0) { | |
66 | error = list_size; | |
67 | goto out; | |
68 | } | |
69 | ||
70 | for (name = buf; list_size; name += slen) { | |
71 | slen = strnlen(name, list_size) + 1; | |
72 | ||
73 | /* underlying fs providing us with an broken xattr list? */ | |
74 | if (WARN_ON(slen > list_size)) { | |
75 | error = -EIO; | |
76 | break; | |
77 | } | |
78 | list_size -= slen; | |
79 | ||
80 | if (ovl_is_private_xattr(name)) | |
81 | continue; | |
82 | retry: | |
83 | size = vfs_getxattr(old, name, value, value_size); | |
84 | if (size == -ERANGE) | |
85 | size = vfs_getxattr(old, name, NULL, 0); | |
86 | ||
87 | if (size < 0) { | |
88 | error = size; | |
89 | break; | |
90 | } | |
91 | ||
92 | if (size > value_size) { | |
93 | void *new; | |
94 | ||
95 | new = krealloc(value, size, GFP_KERNEL); | |
96 | if (!new) { | |
97 | error = -ENOMEM; | |
98 | break; | |
99 | } | |
100 | value = new; | |
101 | value_size = size; | |
102 | goto retry; | |
103 | } | |
104 | ||
105 | error = security_inode_copy_up_xattr(name); | |
106 | if (error < 0 && error != -EOPNOTSUPP) | |
107 | break; | |
108 | if (error == 1) { | |
109 | error = 0; | |
110 | continue; /* Discard */ | |
111 | } | |
112 | error = vfs_setxattr(new, name, value, size, 0); | |
113 | if (error) | |
114 | break; | |
115 | } | |
116 | kfree(value); | |
117 | out: | |
118 | kfree(buf); | |
119 | return error; | |
120 | } | |
121 | ||
122 | static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) | |
123 | { | |
124 | struct file *old_file; | |
125 | struct file *new_file; | |
126 | loff_t old_pos = 0; | |
127 | loff_t new_pos = 0; | |
128 | int error = 0; | |
129 | ||
130 | if (len == 0) | |
131 | return 0; | |
132 | ||
133 | old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); | |
134 | if (IS_ERR(old_file)) | |
135 | return PTR_ERR(old_file); | |
136 | ||
137 | new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); | |
138 | if (IS_ERR(new_file)) { | |
139 | error = PTR_ERR(new_file); | |
140 | goto out_fput; | |
141 | } | |
142 | ||
143 | /* Try to use clone_file_range to clone up within the same fs */ | |
144 | error = vfs_clone_file_range(old_file, 0, new_file, 0, len); | |
145 | if (!error) | |
146 | goto out; | |
147 | /* Couldn't clone, so now we try to copy the data */ | |
148 | error = 0; | |
149 | ||
150 | /* FIXME: copy up sparse files efficiently */ | |
151 | while (len) { | |
152 | size_t this_len = OVL_COPY_UP_CHUNK_SIZE; | |
153 | long bytes; | |
154 | ||
155 | if (len < this_len) | |
156 | this_len = len; | |
157 | ||
158 | if (signal_pending_state(TASK_KILLABLE, current)) { | |
159 | error = -EINTR; | |
160 | break; | |
161 | } | |
162 | ||
163 | bytes = do_splice_direct(old_file, &old_pos, | |
164 | new_file, &new_pos, | |
165 | this_len, SPLICE_F_MOVE); | |
166 | if (bytes <= 0) { | |
167 | error = bytes; | |
168 | break; | |
169 | } | |
170 | WARN_ON(old_pos != new_pos); | |
171 | ||
172 | len -= bytes; | |
173 | } | |
174 | out: | |
175 | if (!error) | |
176 | error = vfs_fsync(new_file, 0); | |
177 | fput(new_file); | |
178 | out_fput: | |
179 | fput(old_file); | |
180 | return error; | |
181 | } | |
182 | ||
183 | static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat) | |
184 | { | |
185 | struct iattr attr = { | |
186 | .ia_valid = ATTR_SIZE, | |
187 | .ia_size = stat->size, | |
188 | }; | |
189 | ||
190 | return notify_change(upperdentry, &attr, NULL); | |
191 | } | |
192 | ||
193 | static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) | |
194 | { | |
195 | struct iattr attr = { | |
196 | .ia_valid = | |
197 | ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, | |
198 | .ia_atime = stat->atime, | |
199 | .ia_mtime = stat->mtime, | |
200 | }; | |
201 | ||
202 | return notify_change(upperdentry, &attr, NULL); | |
203 | } | |
204 | ||
205 | int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) | |
206 | { | |
207 | int err = 0; | |
208 | ||
209 | if (!S_ISLNK(stat->mode)) { | |
210 | struct iattr attr = { | |
211 | .ia_valid = ATTR_MODE, | |
212 | .ia_mode = stat->mode, | |
213 | }; | |
214 | err = notify_change(upperdentry, &attr, NULL); | |
215 | } | |
216 | if (!err) { | |
217 | struct iattr attr = { | |
218 | .ia_valid = ATTR_UID | ATTR_GID, | |
219 | .ia_uid = stat->uid, | |
220 | .ia_gid = stat->gid, | |
221 | }; | |
222 | err = notify_change(upperdentry, &attr, NULL); | |
223 | } | |
224 | if (!err) | |
225 | ovl_set_timestamps(upperdentry, stat); | |
226 | ||
227 | return err; | |
228 | } | |
229 | ||
230 | struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper) | |
231 | { | |
232 | struct ovl_fh *fh; | |
233 | int fh_type, fh_len, dwords; | |
234 | void *buf; | |
235 | int buflen = MAX_HANDLE_SZ; | |
236 | uuid_t *uuid = &real->d_sb->s_uuid; | |
237 | ||
238 | buf = kmalloc(buflen, GFP_KERNEL); | |
239 | if (!buf) | |
240 | return ERR_PTR(-ENOMEM); | |
241 | ||
242 | /* | |
243 | * We encode a non-connectable file handle for non-dir, because we | |
244 | * only need to find the lower inode number and we don't want to pay | |
245 | * the price or reconnecting the dentry. | |
246 | */ | |
247 | dwords = buflen >> 2; | |
248 | fh_type = exportfs_encode_fh(real, buf, &dwords, 0); | |
249 | buflen = (dwords << 2); | |
250 | ||
251 | fh = ERR_PTR(-EIO); | |
252 | if (WARN_ON(fh_type < 0) || | |
253 | WARN_ON(buflen > MAX_HANDLE_SZ) || | |
254 | WARN_ON(fh_type == FILEID_INVALID)) | |
255 | goto out; | |
256 | ||
257 | BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255); | |
258 | fh_len = offsetof(struct ovl_fh, fid) + buflen; | |
259 | fh = kmalloc(fh_len, GFP_KERNEL); | |
260 | if (!fh) { | |
261 | fh = ERR_PTR(-ENOMEM); | |
262 | goto out; | |
263 | } | |
264 | ||
265 | fh->version = OVL_FH_VERSION; | |
266 | fh->magic = OVL_FH_MAGIC; | |
267 | fh->type = fh_type; | |
268 | fh->flags = OVL_FH_FLAG_CPU_ENDIAN; | |
269 | /* | |
270 | * When we will want to decode an overlay dentry from this handle | |
271 | * and all layers are on the same fs, if we get a disconncted real | |
272 | * dentry when we decode fid, the only way to tell if we should assign | |
273 | * it to upperdentry or to lowerstack is by checking this flag. | |
274 | */ | |
275 | if (is_upper) | |
276 | fh->flags |= OVL_FH_FLAG_PATH_UPPER; | |
277 | fh->len = fh_len; | |
278 | fh->uuid = *uuid; | |
279 | memcpy(fh->fid, buf, buflen); | |
280 | ||
281 | out: | |
282 | kfree(buf); | |
283 | return fh; | |
284 | } | |
285 | ||
286 | int ovl_set_origin(struct dentry *dentry, struct dentry *lower, | |
287 | struct dentry *upper) | |
288 | { | |
289 | const struct ovl_fh *fh = NULL; | |
290 | int err; | |
291 | ||
292 | /* | |
293 | * When lower layer doesn't support export operations store a 'null' fh, | |
294 | * so we can use the overlay.origin xattr to distignuish between a copy | |
295 | * up and a pure upper inode. | |
296 | */ | |
297 | if (ovl_can_decode_fh(lower->d_sb)) { | |
298 | fh = ovl_encode_real_fh(lower, false); | |
299 | if (IS_ERR(fh)) | |
300 | return PTR_ERR(fh); | |
301 | } | |
302 | ||
303 | /* | |
304 | * Do not fail when upper doesn't support xattrs. | |
305 | */ | |
306 | err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh, | |
307 | fh ? fh->len : 0, 0); | |
308 | kfree(fh); | |
309 | ||
310 | return err; | |
311 | } | |
312 | ||
313 | /* Store file handle of @upper dir in @index dir entry */ | |
314 | static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index) | |
315 | { | |
316 | const struct ovl_fh *fh; | |
317 | int err; | |
318 | ||
319 | fh = ovl_encode_real_fh(upper, true); | |
320 | if (IS_ERR(fh)) | |
321 | return PTR_ERR(fh); | |
322 | ||
323 | err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh, fh->len, 0); | |
324 | ||
325 | kfree(fh); | |
326 | return err; | |
327 | } | |
328 | ||
329 | /* | |
330 | * Create and install index entry. | |
331 | * | |
332 | * Caller must hold i_mutex on indexdir. | |
333 | */ | |
334 | static int ovl_create_index(struct dentry *dentry, struct dentry *origin, | |
335 | struct dentry *upper) | |
336 | { | |
337 | struct dentry *indexdir = ovl_indexdir(dentry->d_sb); | |
338 | struct inode *dir = d_inode(indexdir); | |
339 | struct dentry *index = NULL; | |
340 | struct dentry *temp = NULL; | |
341 | struct qstr name = { }; | |
342 | int err; | |
343 | ||
344 | /* | |
345 | * For now this is only used for creating index entry for directories, | |
346 | * because non-dir are copied up directly to index and then hardlinked | |
347 | * to upper dir. | |
348 | * | |
349 | * TODO: implement create index for non-dir, so we can call it when | |
350 | * encoding file handle for non-dir in case index does not exist. | |
351 | */ | |
352 | if (WARN_ON(!d_is_dir(dentry))) | |
353 | return -EIO; | |
354 | ||
355 | /* Directory not expected to be indexed before copy up */ | |
356 | if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) | |
357 | return -EIO; | |
358 | ||
359 | err = ovl_get_index_name(origin, &name); | |
360 | if (err) | |
361 | return err; | |
362 | ||
363 | temp = ovl_create_temp(indexdir, OVL_CATTR(S_IFDIR | 0)); | |
364 | err = PTR_ERR(temp); | |
365 | if (IS_ERR(temp)) | |
366 | goto free_name; | |
367 | ||
368 | err = ovl_set_upper_fh(upper, temp); | |
369 | if (err) | |
370 | goto out; | |
371 | ||
372 | index = lookup_one_len(name.name, indexdir, name.len); | |
373 | if (IS_ERR(index)) { | |
374 | err = PTR_ERR(index); | |
375 | } else { | |
376 | err = ovl_do_rename(dir, temp, dir, index, 0); | |
377 | dput(index); | |
378 | } | |
379 | out: | |
380 | if (err) | |
381 | ovl_cleanup(dir, temp); | |
382 | dput(temp); | |
383 | free_name: | |
384 | kfree(name.name); | |
385 | return err; | |
386 | } | |
387 | ||
388 | struct ovl_copy_up_ctx { | |
389 | struct dentry *parent; | |
390 | struct dentry *dentry; | |
391 | struct path lowerpath; | |
392 | struct kstat stat; | |
393 | struct kstat pstat; | |
394 | const char *link; | |
395 | struct dentry *destdir; | |
396 | struct qstr destname; | |
397 | struct dentry *workdir; | |
398 | bool tmpfile; | |
399 | bool origin; | |
400 | bool indexed; | |
401 | bool metacopy; | |
402 | }; | |
403 | ||
404 | static int ovl_link_up(struct ovl_copy_up_ctx *c) | |
405 | { | |
406 | int err; | |
407 | struct dentry *upper; | |
408 | struct dentry *upperdir = ovl_dentry_upper(c->parent); | |
409 | struct inode *udir = d_inode(upperdir); | |
410 | ||
411 | /* Mark parent "impure" because it may now contain non-pure upper */ | |
412 | err = ovl_set_impure(c->parent, upperdir); | |
413 | if (err) | |
414 | return err; | |
415 | ||
416 | err = ovl_set_nlink_lower(c->dentry); | |
417 | if (err) | |
418 | return err; | |
419 | ||
420 | inode_lock_nested(udir, I_MUTEX_PARENT); | |
421 | upper = lookup_one_len(c->dentry->d_name.name, upperdir, | |
422 | c->dentry->d_name.len); | |
423 | err = PTR_ERR(upper); | |
424 | if (!IS_ERR(upper)) { | |
425 | err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper); | |
426 | dput(upper); | |
427 | ||
428 | if (!err) { | |
429 | /* Restore timestamps on parent (best effort) */ | |
430 | ovl_set_timestamps(upperdir, &c->pstat); | |
431 | ovl_dentry_set_upper_alias(c->dentry); | |
432 | } | |
433 | } | |
434 | inode_unlock(udir); | |
435 | if (err) | |
436 | return err; | |
437 | ||
438 | err = ovl_set_nlink_upper(c->dentry); | |
439 | ||
440 | return err; | |
441 | } | |
442 | ||
443 | static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp, | |
444 | struct dentry **newdentry) | |
445 | { | |
446 | int err; | |
447 | struct dentry *upper; | |
448 | struct inode *udir = d_inode(c->destdir); | |
449 | ||
450 | upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len); | |
451 | if (IS_ERR(upper)) | |
452 | return PTR_ERR(upper); | |
453 | ||
454 | if (c->tmpfile) | |
455 | err = ovl_do_link(temp, udir, upper); | |
456 | else | |
457 | err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0); | |
458 | ||
459 | if (!err) | |
460 | *newdentry = dget(c->tmpfile ? upper : temp); | |
461 | dput(upper); | |
462 | ||
463 | return err; | |
464 | } | |
465 | ||
466 | static struct dentry *ovl_get_tmpfile(struct ovl_copy_up_ctx *c) | |
467 | { | |
468 | int err; | |
469 | struct dentry *temp; | |
470 | const struct cred *old_creds = NULL; | |
471 | struct cred *new_creds = NULL; | |
472 | struct ovl_cattr cattr = { | |
473 | /* Can't properly set mode on creation because of the umask */ | |
474 | .mode = c->stat.mode & S_IFMT, | |
475 | .rdev = c->stat.rdev, | |
476 | .link = c->link | |
477 | }; | |
478 | ||
479 | err = security_inode_copy_up(c->dentry, &new_creds); | |
480 | temp = ERR_PTR(err); | |
481 | if (err < 0) | |
482 | goto out; | |
483 | ||
484 | if (new_creds) | |
485 | old_creds = override_creds(new_creds); | |
486 | ||
487 | if (c->tmpfile) | |
488 | temp = ovl_do_tmpfile(c->workdir, c->stat.mode); | |
489 | else | |
490 | temp = ovl_create_temp(c->workdir, &cattr); | |
491 | out: | |
492 | if (new_creds) { | |
493 | revert_creds(old_creds); | |
494 | put_cred(new_creds); | |
495 | } | |
496 | ||
497 | return temp; | |
498 | } | |
499 | ||
500 | static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) | |
501 | { | |
502 | int err; | |
503 | ||
504 | err = ovl_copy_xattr(c->lowerpath.dentry, temp); | |
505 | if (err) | |
506 | return err; | |
507 | ||
508 | /* | |
509 | * Store identifier of lower inode in upper inode xattr to | |
510 | * allow lookup of the copy up origin inode. | |
511 | * | |
512 | * Don't set origin when we are breaking the association with a lower | |
513 | * hard link. | |
514 | */ | |
515 | if (c->origin) { | |
516 | err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp); | |
517 | if (err) | |
518 | return err; | |
519 | } | |
520 | ||
521 | if (S_ISREG(c->stat.mode) && !c->metacopy) { | |
522 | struct path upperpath, datapath; | |
523 | ||
524 | ovl_path_upper(c->dentry, &upperpath); | |
525 | BUG_ON(upperpath.dentry != NULL); | |
526 | upperpath.dentry = temp; | |
527 | ||
528 | ovl_path_lowerdata(c->dentry, &datapath); | |
529 | err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size); | |
530 | if (err) | |
531 | return err; | |
532 | } | |
533 | ||
534 | if (c->metacopy) { | |
535 | err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY, | |
536 | NULL, 0, -EOPNOTSUPP); | |
537 | if (err) | |
538 | return err; | |
539 | } | |
540 | ||
541 | inode_lock(temp->d_inode); | |
542 | if (c->metacopy) | |
543 | err = ovl_set_size(temp, &c->stat); | |
544 | if (!err) | |
545 | err = ovl_set_attr(temp, &c->stat); | |
546 | inode_unlock(temp->d_inode); | |
547 | ||
548 | return err; | |
549 | } | |
550 | ||
551 | static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c) | |
552 | { | |
553 | struct inode *udir = c->destdir->d_inode; | |
554 | struct inode *inode; | |
555 | struct dentry *newdentry = NULL; | |
556 | struct dentry *temp; | |
557 | int err; | |
558 | ||
559 | temp = ovl_get_tmpfile(c); | |
560 | if (IS_ERR(temp)) | |
561 | return PTR_ERR(temp); | |
562 | ||
563 | err = ovl_copy_up_inode(c, temp); | |
564 | if (err) | |
565 | goto out; | |
566 | ||
567 | if (S_ISDIR(c->stat.mode) && c->indexed) { | |
568 | err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp); | |
569 | if (err) | |
570 | goto out; | |
571 | } | |
572 | ||
573 | if (c->tmpfile) { | |
574 | inode_lock_nested(udir, I_MUTEX_PARENT); | |
575 | err = ovl_install_temp(c, temp, &newdentry); | |
576 | inode_unlock(udir); | |
577 | } else { | |
578 | err = ovl_install_temp(c, temp, &newdentry); | |
579 | } | |
580 | if (err) | |
581 | goto out; | |
582 | ||
583 | if (!c->metacopy) | |
584 | ovl_set_upperdata(d_inode(c->dentry)); | |
585 | inode = d_inode(c->dentry); | |
586 | ovl_inode_update(inode, newdentry); | |
587 | if (S_ISDIR(inode->i_mode)) | |
588 | ovl_set_flag(OVL_WHITEOUTS, inode); | |
589 | ||
590 | out: | |
591 | if (err && !c->tmpfile) | |
592 | ovl_cleanup(d_inode(c->workdir), temp); | |
593 | dput(temp); | |
594 | return err; | |
595 | ||
596 | } | |
597 | ||
598 | /* | |
599 | * Copy up a single dentry | |
600 | * | |
601 | * All renames start with copy up of source if necessary. The actual | |
602 | * rename will only proceed once the copy up was successful. Copy up uses | |
603 | * upper parent i_mutex for exclusion. Since rename can change d_parent it | |
604 | * is possible that the copy up will lock the old parent. At that point | |
605 | * the file will have already been copied up anyway. | |
606 | */ | |
607 | static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) | |
608 | { | |
609 | int err; | |
610 | struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; | |
611 | bool to_index = false; | |
612 | ||
613 | /* | |
614 | * Indexed non-dir is copied up directly to the index entry and then | |
615 | * hardlinked to upper dir. Indexed dir is copied up to indexdir, | |
616 | * then index entry is created and then copied up dir installed. | |
617 | * Copying dir up to indexdir instead of workdir simplifies locking. | |
618 | */ | |
619 | if (ovl_need_index(c->dentry)) { | |
620 | c->indexed = true; | |
621 | if (S_ISDIR(c->stat.mode)) | |
622 | c->workdir = ovl_indexdir(c->dentry->d_sb); | |
623 | else | |
624 | to_index = true; | |
625 | } | |
626 | ||
627 | if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) | |
628 | c->origin = true; | |
629 | ||
630 | if (to_index) { | |
631 | c->destdir = ovl_indexdir(c->dentry->d_sb); | |
632 | err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); | |
633 | if (err) | |
634 | return err; | |
635 | } else if (WARN_ON(!c->parent)) { | |
636 | /* Disconnected dentry must be copied up to index dir */ | |
637 | return -EIO; | |
638 | } else { | |
639 | /* | |
640 | * Mark parent "impure" because it may now contain non-pure | |
641 | * upper | |
642 | */ | |
643 | err = ovl_set_impure(c->parent, c->destdir); | |
644 | if (err) | |
645 | return err; | |
646 | } | |
647 | ||
648 | /* Should we copyup with O_TMPFILE or with workdir? */ | |
649 | if (S_ISREG(c->stat.mode) && ofs->tmpfile) { | |
650 | c->tmpfile = true; | |
651 | err = ovl_copy_up_locked(c); | |
652 | } else { | |
653 | err = ovl_lock_rename_workdir(c->workdir, c->destdir); | |
654 | if (!err) { | |
655 | err = ovl_copy_up_locked(c); | |
656 | unlock_rename(c->workdir, c->destdir); | |
657 | } | |
658 | } | |
659 | ||
660 | ||
661 | if (err) | |
662 | goto out; | |
663 | ||
664 | if (c->indexed) | |
665 | ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); | |
666 | ||
667 | if (to_index) { | |
668 | /* Initialize nlink for copy up of disconnected dentry */ | |
669 | err = ovl_set_nlink_upper(c->dentry); | |
670 | } else { | |
671 | struct inode *udir = d_inode(c->destdir); | |
672 | ||
673 | /* Restore timestamps on parent (best effort) */ | |
674 | inode_lock(udir); | |
675 | ovl_set_timestamps(c->destdir, &c->pstat); | |
676 | inode_unlock(udir); | |
677 | ||
678 | ovl_dentry_set_upper_alias(c->dentry); | |
679 | } | |
680 | ||
681 | out: | |
682 | if (to_index) | |
683 | kfree(c->destname.name); | |
684 | return err; | |
685 | } | |
686 | ||
687 | static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode, | |
688 | int flags) | |
689 | { | |
690 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
691 | ||
692 | /* TODO: Will enable metacopy in last patch of series */ | |
693 | return false; | |
694 | ||
695 | if (!ofs->config.metacopy) | |
696 | return false; | |
697 | ||
698 | if (!S_ISREG(mode)) | |
699 | return false; | |
700 | ||
701 | if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC))) | |
702 | return false; | |
703 | ||
704 | return true; | |
705 | } | |
706 | ||
707 | /* Copy up data of an inode which was copied up metadata only in the past. */ | |
708 | static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) | |
709 | { | |
710 | struct path upperpath, datapath; | |
711 | int err; | |
712 | ||
713 | ovl_path_upper(c->dentry, &upperpath); | |
714 | if (WARN_ON(upperpath.dentry == NULL)) | |
715 | return -EIO; | |
716 | ||
717 | ovl_path_lowerdata(c->dentry, &datapath); | |
718 | if (WARN_ON(datapath.dentry == NULL)) | |
719 | return -EIO; | |
720 | ||
721 | err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size); | |
722 | if (err) | |
723 | return err; | |
724 | ||
725 | err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY); | |
726 | if (err) | |
727 | return err; | |
728 | ||
729 | ovl_set_upperdata(d_inode(c->dentry)); | |
730 | return err; | |
731 | } | |
732 | ||
733 | static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, | |
734 | int flags) | |
735 | { | |
736 | int err; | |
737 | DEFINE_DELAYED_CALL(done); | |
738 | struct path parentpath; | |
739 | struct ovl_copy_up_ctx ctx = { | |
740 | .parent = parent, | |
741 | .dentry = dentry, | |
742 | .workdir = ovl_workdir(dentry), | |
743 | }; | |
744 | ||
745 | if (WARN_ON(!ctx.workdir)) | |
746 | return -EROFS; | |
747 | ||
748 | ovl_path_lower(dentry, &ctx.lowerpath); | |
749 | err = vfs_getattr(&ctx.lowerpath, &ctx.stat, | |
750 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
751 | if (err) | |
752 | return err; | |
753 | ||
754 | ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags); | |
755 | ||
756 | if (parent) { | |
757 | ovl_path_upper(parent, &parentpath); | |
758 | ctx.destdir = parentpath.dentry; | |
759 | ctx.destname = dentry->d_name; | |
760 | ||
761 | err = vfs_getattr(&parentpath, &ctx.pstat, | |
762 | STATX_ATIME | STATX_MTIME, | |
763 | AT_STATX_SYNC_AS_STAT); | |
764 | if (err) | |
765 | return err; | |
766 | } | |
767 | ||
768 | /* maybe truncate regular file. this has no effect on dirs */ | |
769 | if (flags & O_TRUNC) | |
770 | ctx.stat.size = 0; | |
771 | ||
772 | if (S_ISLNK(ctx.stat.mode)) { | |
773 | ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); | |
774 | if (IS_ERR(ctx.link)) | |
775 | return PTR_ERR(ctx.link); | |
776 | } | |
777 | ||
778 | err = ovl_copy_up_start(dentry, flags); | |
779 | /* err < 0: interrupted, err > 0: raced with another copy-up */ | |
780 | if (unlikely(err)) { | |
781 | if (err > 0) | |
782 | err = 0; | |
783 | } else { | |
784 | if (!ovl_dentry_upper(dentry)) | |
785 | err = ovl_do_copy_up(&ctx); | |
786 | if (!err && parent && !ovl_dentry_has_upper_alias(dentry)) | |
787 | err = ovl_link_up(&ctx); | |
788 | if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags)) | |
789 | err = ovl_copy_up_meta_inode_data(&ctx); | |
790 | ovl_copy_up_end(dentry); | |
791 | } | |
792 | do_delayed_call(&done); | |
793 | ||
794 | return err; | |
795 | } | |
796 | ||
797 | int ovl_copy_up_flags(struct dentry *dentry, int flags) | |
798 | { | |
799 | int err = 0; | |
800 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); | |
801 | bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED); | |
802 | ||
803 | /* | |
804 | * With NFS export, copy up can get called for a disconnected non-dir. | |
805 | * In this case, we will copy up lower inode to index dir without | |
806 | * linking it to upper dir. | |
807 | */ | |
808 | if (WARN_ON(disconnected && d_is_dir(dentry))) | |
809 | return -EIO; | |
810 | ||
811 | while (!err) { | |
812 | struct dentry *next; | |
813 | struct dentry *parent = NULL; | |
814 | ||
815 | if (ovl_already_copied_up(dentry, flags)) | |
816 | break; | |
817 | ||
818 | next = dget(dentry); | |
819 | /* find the topmost dentry not yet copied up */ | |
820 | for (; !disconnected;) { | |
821 | parent = dget_parent(next); | |
822 | ||
823 | if (ovl_dentry_upper(parent)) | |
824 | break; | |
825 | ||
826 | dput(next); | |
827 | next = parent; | |
828 | } | |
829 | ||
830 | err = ovl_copy_up_one(parent, next, flags); | |
831 | ||
832 | dput(parent); | |
833 | dput(next); | |
834 | } | |
835 | revert_creds(old_cred); | |
836 | ||
837 | return err; | |
838 | } | |
839 | ||
840 | static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) | |
841 | { | |
842 | /* Copy up of disconnected dentry does not set upper alias */ | |
843 | if (ovl_already_copied_up(dentry, flags)) | |
844 | return false; | |
845 | ||
846 | if (special_file(d_inode(dentry)->i_mode)) | |
847 | return false; | |
848 | ||
849 | if (!ovl_open_flags_need_copy_up(flags)) | |
850 | return false; | |
851 | ||
852 | return true; | |
853 | } | |
854 | ||
855 | int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) | |
856 | { | |
857 | int err = 0; | |
858 | ||
859 | if (ovl_open_need_copy_up(dentry, file_flags)) { | |
860 | err = ovl_want_write(dentry); | |
861 | if (!err) { | |
862 | err = ovl_copy_up_flags(dentry, file_flags); | |
863 | ovl_drop_write(dentry); | |
864 | } | |
865 | } | |
866 | ||
867 | return err; | |
868 | } | |
869 | ||
870 | int ovl_copy_up(struct dentry *dentry) | |
871 | { | |
872 | return ovl_copy_up_flags(dentry, 0); | |
873 | } |