Commit | Line | Data |
---|---|---|
e9be9d5e MS |
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 | ||
fb5bb2c3 | 10 | #include <linux/module.h> |
e9be9d5e MS |
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> | |
174cd4b1 | 18 | #include <linux/sched/signal.h> |
5b825c3a | 19 | #include <linux/cred.h> |
e9be9d5e | 20 | #include <linux/namei.h> |
fb5bb2c3 DH |
21 | #include <linux/fdtable.h> |
22 | #include <linux/ratelimit.h> | |
3a1e819b | 23 | #include <linux/exportfs.h> |
e9be9d5e | 24 | #include "overlayfs.h" |
d8514d8e | 25 | #include "ovl_entry.h" |
e9be9d5e MS |
26 | |
27 | #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) | |
28 | ||
fb5bb2c3 DH |
29 | static bool __read_mostly ovl_check_copy_up; |
30 | module_param_named(check_copy_up, ovl_check_copy_up, bool, | |
31 | S_IWUSR | S_IRUGO); | |
32 | MODULE_PARM_DESC(ovl_check_copy_up, | |
33 | "Warn on copy-up when causing process also has a R/O fd open"); | |
34 | ||
35 | static int ovl_check_fd(const void *data, struct file *f, unsigned int fd) | |
36 | { | |
37 | const struct dentry *dentry = data; | |
38 | ||
45063097 | 39 | if (file_inode(f) == d_inode(dentry)) |
fb5bb2c3 DH |
40 | pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n", |
41 | f, fd, current->pid, current->comm); | |
42 | return 0; | |
43 | } | |
44 | ||
45 | /* | |
46 | * Check the fds open by this process and warn if something like the following | |
47 | * scenario is about to occur: | |
48 | * | |
49 | * fd1 = open("foo", O_RDONLY); | |
50 | * fd2 = open("foo", O_RDWR); | |
51 | */ | |
52 | static void ovl_do_check_copy_up(struct dentry *dentry) | |
53 | { | |
54 | if (ovl_check_copy_up) | |
55 | iterate_fd(current->files, 0, ovl_check_fd, dentry); | |
56 | } | |
57 | ||
e9be9d5e MS |
58 | int ovl_copy_xattr(struct dentry *old, struct dentry *new) |
59 | { | |
e4ad29fa VC |
60 | ssize_t list_size, size, value_size = 0; |
61 | char *buf, *name, *value = NULL; | |
62 | int uninitialized_var(error); | |
8b326c61 | 63 | size_t slen; |
e9be9d5e | 64 | |
5d6c3191 AG |
65 | if (!(old->d_inode->i_opflags & IOP_XATTR) || |
66 | !(new->d_inode->i_opflags & IOP_XATTR)) | |
e9be9d5e MS |
67 | return 0; |
68 | ||
69 | list_size = vfs_listxattr(old, NULL, 0); | |
70 | if (list_size <= 0) { | |
71 | if (list_size == -EOPNOTSUPP) | |
72 | return 0; | |
73 | return list_size; | |
74 | } | |
75 | ||
76 | buf = kzalloc(list_size, GFP_KERNEL); | |
77 | if (!buf) | |
78 | return -ENOMEM; | |
79 | ||
e9be9d5e MS |
80 | list_size = vfs_listxattr(old, buf, list_size); |
81 | if (list_size <= 0) { | |
82 | error = list_size; | |
e4ad29fa | 83 | goto out; |
e9be9d5e MS |
84 | } |
85 | ||
8b326c61 MS |
86 | for (name = buf; list_size; name += slen) { |
87 | slen = strnlen(name, list_size) + 1; | |
88 | ||
89 | /* underlying fs providing us with an broken xattr list? */ | |
90 | if (WARN_ON(slen > list_size)) { | |
91 | error = -EIO; | |
92 | break; | |
93 | } | |
94 | list_size -= slen; | |
95 | ||
0956254a MS |
96 | if (ovl_is_private_xattr(name)) |
97 | continue; | |
e4ad29fa VC |
98 | retry: |
99 | size = vfs_getxattr(old, name, value, value_size); | |
100 | if (size == -ERANGE) | |
101 | size = vfs_getxattr(old, name, NULL, 0); | |
102 | ||
97daf8b9 | 103 | if (size < 0) { |
e9be9d5e | 104 | error = size; |
e4ad29fa | 105 | break; |
e9be9d5e | 106 | } |
e4ad29fa VC |
107 | |
108 | if (size > value_size) { | |
109 | void *new; | |
110 | ||
111 | new = krealloc(value, size, GFP_KERNEL); | |
112 | if (!new) { | |
113 | error = -ENOMEM; | |
114 | break; | |
115 | } | |
116 | value = new; | |
117 | value_size = size; | |
118 | goto retry; | |
119 | } | |
120 | ||
121ab822 VG |
121 | error = security_inode_copy_up_xattr(name); |
122 | if (error < 0 && error != -EOPNOTSUPP) | |
123 | break; | |
124 | if (error == 1) { | |
125 | error = 0; | |
126 | continue; /* Discard */ | |
127 | } | |
e9be9d5e MS |
128 | error = vfs_setxattr(new, name, value, size, 0); |
129 | if (error) | |
e4ad29fa | 130 | break; |
e9be9d5e | 131 | } |
e9be9d5e MS |
132 | kfree(value); |
133 | out: | |
134 | kfree(buf); | |
135 | return error; | |
136 | } | |
137 | ||
138 | static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) | |
139 | { | |
140 | struct file *old_file; | |
141 | struct file *new_file; | |
142 | loff_t old_pos = 0; | |
143 | loff_t new_pos = 0; | |
144 | int error = 0; | |
145 | ||
146 | if (len == 0) | |
147 | return 0; | |
148 | ||
0480334f | 149 | old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); |
e9be9d5e MS |
150 | if (IS_ERR(old_file)) |
151 | return PTR_ERR(old_file); | |
152 | ||
0480334f | 153 | new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); |
e9be9d5e MS |
154 | if (IS_ERR(new_file)) { |
155 | error = PTR_ERR(new_file); | |
156 | goto out_fput; | |
157 | } | |
158 | ||
2ea98466 AG |
159 | /* Try to use clone_file_range to clone up within the same fs */ |
160 | error = vfs_clone_file_range(old_file, 0, new_file, 0, len); | |
161 | if (!error) | |
162 | goto out; | |
163 | /* Couldn't clone, so now we try to copy the data */ | |
164 | error = 0; | |
165 | ||
e9be9d5e MS |
166 | /* FIXME: copy up sparse files efficiently */ |
167 | while (len) { | |
168 | size_t this_len = OVL_COPY_UP_CHUNK_SIZE; | |
169 | long bytes; | |
170 | ||
171 | if (len < this_len) | |
172 | this_len = len; | |
173 | ||
174 | if (signal_pending_state(TASK_KILLABLE, current)) { | |
175 | error = -EINTR; | |
176 | break; | |
177 | } | |
178 | ||
179 | bytes = do_splice_direct(old_file, &old_pos, | |
180 | new_file, &new_pos, | |
181 | this_len, SPLICE_F_MOVE); | |
182 | if (bytes <= 0) { | |
183 | error = bytes; | |
184 | break; | |
185 | } | |
186 | WARN_ON(old_pos != new_pos); | |
187 | ||
188 | len -= bytes; | |
189 | } | |
2ea98466 | 190 | out: |
641089c1 MS |
191 | if (!error) |
192 | error = vfs_fsync(new_file, 0); | |
e9be9d5e MS |
193 | fput(new_file); |
194 | out_fput: | |
195 | fput(old_file); | |
196 | return error; | |
197 | } | |
198 | ||
e9be9d5e MS |
199 | static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) |
200 | { | |
201 | struct iattr attr = { | |
202 | .ia_valid = | |
203 | ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, | |
204 | .ia_atime = stat->atime, | |
205 | .ia_mtime = stat->mtime, | |
206 | }; | |
207 | ||
208 | return notify_change(upperdentry, &attr, NULL); | |
209 | } | |
210 | ||
211 | int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) | |
212 | { | |
213 | int err = 0; | |
214 | ||
215 | if (!S_ISLNK(stat->mode)) { | |
216 | struct iattr attr = { | |
217 | .ia_valid = ATTR_MODE, | |
218 | .ia_mode = stat->mode, | |
219 | }; | |
220 | err = notify_change(upperdentry, &attr, NULL); | |
221 | } | |
222 | if (!err) { | |
223 | struct iattr attr = { | |
224 | .ia_valid = ATTR_UID | ATTR_GID, | |
225 | .ia_uid = stat->uid, | |
226 | .ia_gid = stat->gid, | |
227 | }; | |
228 | err = notify_change(upperdentry, &attr, NULL); | |
229 | } | |
230 | if (!err) | |
231 | ovl_set_timestamps(upperdentry, stat); | |
232 | ||
233 | return err; | |
e9be9d5e MS |
234 | } |
235 | ||
54fb347e | 236 | struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper) |
3a1e819b AG |
237 | { |
238 | struct ovl_fh *fh; | |
239 | int fh_type, fh_len, dwords; | |
240 | void *buf; | |
241 | int buflen = MAX_HANDLE_SZ; | |
02bcd157 | 242 | uuid_t *uuid = &lower->d_sb->s_uuid; |
3a1e819b AG |
243 | |
244 | buf = kmalloc(buflen, GFP_TEMPORARY); | |
245 | if (!buf) | |
246 | return ERR_PTR(-ENOMEM); | |
247 | ||
248 | /* | |
249 | * We encode a non-connectable file handle for non-dir, because we | |
250 | * only need to find the lower inode number and we don't want to pay | |
251 | * the price or reconnecting the dentry. | |
252 | */ | |
253 | dwords = buflen >> 2; | |
254 | fh_type = exportfs_encode_fh(lower, buf, &dwords, 0); | |
255 | buflen = (dwords << 2); | |
256 | ||
257 | fh = ERR_PTR(-EIO); | |
258 | if (WARN_ON(fh_type < 0) || | |
259 | WARN_ON(buflen > MAX_HANDLE_SZ) || | |
260 | WARN_ON(fh_type == FILEID_INVALID)) | |
261 | goto out; | |
262 | ||
263 | BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255); | |
264 | fh_len = offsetof(struct ovl_fh, fid) + buflen; | |
265 | fh = kmalloc(fh_len, GFP_KERNEL); | |
266 | if (!fh) { | |
267 | fh = ERR_PTR(-ENOMEM); | |
268 | goto out; | |
269 | } | |
270 | ||
271 | fh->version = OVL_FH_VERSION; | |
272 | fh->magic = OVL_FH_MAGIC; | |
273 | fh->type = fh_type; | |
274 | fh->flags = OVL_FH_FLAG_CPU_ENDIAN; | |
54fb347e AG |
275 | /* |
276 | * When we will want to decode an overlay dentry from this handle | |
277 | * and all layers are on the same fs, if we get a disconncted real | |
278 | * dentry when we decode fid, the only way to tell if we should assign | |
279 | * it to upperdentry or to lowerstack is by checking this flag. | |
280 | */ | |
281 | if (is_upper) | |
282 | fh->flags |= OVL_FH_FLAG_PATH_UPPER; | |
3a1e819b AG |
283 | fh->len = fh_len; |
284 | fh->uuid = *uuid; | |
285 | memcpy(fh->fid, buf, buflen); | |
286 | ||
287 | out: | |
288 | kfree(buf); | |
289 | return fh; | |
290 | } | |
291 | ||
292 | static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, | |
293 | struct dentry *upper) | |
294 | { | |
3a1e819b AG |
295 | const struct ovl_fh *fh = NULL; |
296 | int err; | |
297 | ||
298 | /* | |
299 | * When lower layer doesn't support export operations store a 'null' fh, | |
300 | * so we can use the overlay.origin xattr to distignuish between a copy | |
301 | * up and a pure upper inode. | |
302 | */ | |
02bcd157 | 303 | if (ovl_can_decode_fh(lower->d_sb)) { |
54fb347e | 304 | fh = ovl_encode_fh(lower, false); |
3a1e819b AG |
305 | if (IS_ERR(fh)) |
306 | return PTR_ERR(fh); | |
307 | } | |
308 | ||
6266d465 MS |
309 | /* |
310 | * Do not fail when upper doesn't support xattrs. | |
311 | */ | |
312 | err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh, | |
313 | fh ? fh->len : 0, 0); | |
3a1e819b AG |
314 | kfree(fh); |
315 | ||
316 | return err; | |
317 | } | |
318 | ||
f4439de1 AG |
319 | struct ovl_copy_up_ctx { |
320 | struct dentry *parent; | |
321 | struct dentry *dentry; | |
322 | struct path lowerpath; | |
323 | struct kstat stat; | |
324 | struct kstat pstat; | |
325 | const char *link; | |
326 | struct dentry *destdir; | |
327 | struct qstr destname; | |
328 | struct dentry *workdir; | |
329 | bool tmpfile; | |
330 | bool origin; | |
331 | }; | |
332 | ||
333 | static int ovl_link_up(struct ovl_copy_up_ctx *c) | |
59be0971 AG |
334 | { |
335 | int err; | |
336 | struct dentry *upper; | |
f4439de1 | 337 | struct dentry *upperdir = ovl_dentry_upper(c->parent); |
59be0971 AG |
338 | struct inode *udir = d_inode(upperdir); |
339 | ||
f4439de1 AG |
340 | /* Mark parent "impure" because it may now contain non-pure upper */ |
341 | err = ovl_set_impure(c->parent, upperdir); | |
342 | if (err) | |
343 | return err; | |
344 | ||
345 | err = ovl_set_nlink_lower(c->dentry); | |
5f8415d6 AG |
346 | if (err) |
347 | return err; | |
348 | ||
59be0971 | 349 | inode_lock_nested(udir, I_MUTEX_PARENT); |
f4439de1 AG |
350 | upper = lookup_one_len(c->dentry->d_name.name, upperdir, |
351 | c->dentry->d_name.len); | |
59be0971 AG |
352 | err = PTR_ERR(upper); |
353 | if (!IS_ERR(upper)) { | |
f4439de1 AG |
354 | err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper, |
355 | true); | |
59be0971 AG |
356 | dput(upper); |
357 | ||
f4439de1 AG |
358 | if (!err) { |
359 | /* Restore timestamps on parent (best effort) */ | |
360 | ovl_set_timestamps(upperdir, &c->pstat); | |
361 | ovl_dentry_set_upper_alias(c->dentry); | |
362 | } | |
59be0971 AG |
363 | } |
364 | inode_unlock(udir); | |
f4439de1 | 365 | ovl_set_nlink_upper(c->dentry); |
59be0971 AG |
366 | |
367 | return err; | |
368 | } | |
369 | ||
23f0ab13 MS |
370 | static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp, |
371 | struct dentry **newdentry) | |
15932c41 AG |
372 | { |
373 | int err; | |
374 | struct dentry *upper; | |
59be0971 | 375 | struct inode *udir = d_inode(c->destdir); |
15932c41 | 376 | |
59be0971 | 377 | upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len); |
15932c41 AG |
378 | if (IS_ERR(upper)) |
379 | return PTR_ERR(upper); | |
380 | ||
23f0ab13 | 381 | if (c->tmpfile) |
15932c41 AG |
382 | err = ovl_do_link(temp, udir, upper, true); |
383 | else | |
23f0ab13 | 384 | err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0); |
15932c41 | 385 | |
59be0971 | 386 | if (!err) |
23f0ab13 | 387 | *newdentry = dget(c->tmpfile ? upper : temp); |
15932c41 AG |
388 | dput(upper); |
389 | ||
390 | return err; | |
391 | } | |
392 | ||
23f0ab13 | 393 | static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp) |
e9be9d5e | 394 | { |
e9be9d5e | 395 | int err; |
7d90b853 | 396 | struct dentry *temp; |
d8ad8b49 VG |
397 | const struct cred *old_creds = NULL; |
398 | struct cred *new_creds = NULL; | |
32a3d848 AV |
399 | struct cattr cattr = { |
400 | /* Can't properly set mode on creation because of the umask */ | |
23f0ab13 MS |
401 | .mode = c->stat.mode & S_IFMT, |
402 | .rdev = c->stat.rdev, | |
403 | .link = c->link | |
32a3d848 | 404 | }; |
e9be9d5e | 405 | |
23f0ab13 | 406 | err = security_inode_copy_up(c->dentry, &new_creds); |
d8ad8b49 | 407 | if (err < 0) |
e85f82ff | 408 | goto out; |
d8ad8b49 VG |
409 | |
410 | if (new_creds) | |
411 | old_creds = override_creds(new_creds); | |
412 | ||
23f0ab13 MS |
413 | if (c->tmpfile) { |
414 | temp = ovl_do_tmpfile(c->workdir, c->stat.mode); | |
7d90b853 MS |
415 | if (IS_ERR(temp)) |
416 | goto temp_err; | |
417 | } else { | |
23f0ab13 | 418 | temp = ovl_lookup_temp(c->workdir); |
7d90b853 MS |
419 | if (IS_ERR(temp)) |
420 | goto temp_err; | |
421 | ||
23f0ab13 | 422 | err = ovl_create_real(d_inode(c->workdir), temp, &cattr, |
7d90b853 MS |
423 | NULL, true); |
424 | if (err) { | |
425 | dput(temp); | |
426 | goto out; | |
427 | } | |
8137ae26 | 428 | } |
7d90b853 MS |
429 | err = 0; |
430 | *tempp = temp; | |
431 | out: | |
d8ad8b49 VG |
432 | if (new_creds) { |
433 | revert_creds(old_creds); | |
434 | put_cred(new_creds); | |
435 | } | |
436 | ||
7d90b853 MS |
437 | return err; |
438 | ||
439 | temp_err: | |
440 | err = PTR_ERR(temp); | |
441 | goto out; | |
442 | } | |
443 | ||
23f0ab13 | 444 | static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) |
7d90b853 | 445 | { |
7d90b853 MS |
446 | int err; |
447 | ||
23f0ab13 | 448 | if (S_ISREG(c->stat.mode)) { |
e9be9d5e | 449 | struct path upperpath; |
f134f244 | 450 | |
23f0ab13 | 451 | ovl_path_upper(c->dentry, &upperpath); |
e9be9d5e | 452 | BUG_ON(upperpath.dentry != NULL); |
42f269b9 | 453 | upperpath.dentry = temp; |
e9be9d5e | 454 | |
23f0ab13 | 455 | err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size); |
e9be9d5e | 456 | if (err) |
02209d10 | 457 | return err; |
e9be9d5e MS |
458 | } |
459 | ||
23f0ab13 | 460 | err = ovl_copy_xattr(c->lowerpath.dentry, temp); |
e9be9d5e | 461 | if (err) |
02209d10 | 462 | return err; |
e9be9d5e | 463 | |
42f269b9 | 464 | inode_lock(temp->d_inode); |
23f0ab13 | 465 | err = ovl_set_attr(temp, &c->stat); |
42f269b9 | 466 | inode_unlock(temp->d_inode); |
e9be9d5e | 467 | if (err) |
02209d10 | 468 | return err; |
e9be9d5e | 469 | |
3a1e819b AG |
470 | /* |
471 | * Store identifier of lower inode in upper inode xattr to | |
472 | * allow lookup of the copy up origin inode. | |
fbaf94ee MS |
473 | * |
474 | * Don't set origin when we are breaking the association with a lower | |
475 | * hard link. | |
3a1e819b | 476 | */ |
59be0971 | 477 | if (c->origin) { |
23f0ab13 | 478 | err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp); |
fbaf94ee | 479 | if (err) |
02209d10 | 480 | return err; |
fbaf94ee | 481 | } |
3a1e819b | 482 | |
02209d10 AG |
483 | return 0; |
484 | } | |
485 | ||
23f0ab13 | 486 | static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c) |
02209d10 | 487 | { |
59be0971 | 488 | struct inode *udir = c->destdir->d_inode; |
02209d10 AG |
489 | struct dentry *newdentry = NULL; |
490 | struct dentry *temp = NULL; | |
491 | int err; | |
492 | ||
23f0ab13 | 493 | err = ovl_get_tmpfile(c, &temp); |
02209d10 AG |
494 | if (err) |
495 | goto out; | |
496 | ||
23f0ab13 | 497 | err = ovl_copy_up_inode(c, temp); |
02209d10 AG |
498 | if (err) |
499 | goto out_cleanup; | |
500 | ||
23f0ab13 | 501 | if (c->tmpfile) { |
15932c41 | 502 | inode_lock_nested(udir, I_MUTEX_PARENT); |
23f0ab13 | 503 | err = ovl_install_temp(c, temp, &newdentry); |
15932c41 AG |
504 | inode_unlock(udir); |
505 | } else { | |
23f0ab13 | 506 | err = ovl_install_temp(c, temp, &newdentry); |
e85f82ff | 507 | } |
e9be9d5e MS |
508 | if (err) |
509 | goto out_cleanup; | |
510 | ||
23f0ab13 | 511 | ovl_inode_update(d_inode(c->dentry), newdentry); |
e85f82ff | 512 | out: |
42f269b9 | 513 | dput(temp); |
e9be9d5e MS |
514 | return err; |
515 | ||
516 | out_cleanup: | |
23f0ab13 MS |
517 | if (!c->tmpfile) |
518 | ovl_cleanup(d_inode(c->workdir), temp); | |
e85f82ff | 519 | goto out; |
e9be9d5e MS |
520 | } |
521 | ||
522 | /* | |
523 | * Copy up a single dentry | |
524 | * | |
a6c60655 MS |
525 | * All renames start with copy up of source if necessary. The actual |
526 | * rename will only proceed once the copy up was successful. Copy up uses | |
527 | * upper parent i_mutex for exclusion. Since rename can change d_parent it | |
528 | * is possible that the copy up will lock the old parent. At that point | |
529 | * the file will have already been copied up anyway. | |
e9be9d5e | 530 | */ |
a6fb235a | 531 | static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) |
e9be9d5e | 532 | { |
e9be9d5e | 533 | int err; |
23f0ab13 | 534 | struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; |
59be0971 | 535 | bool indexed = false; |
e9be9d5e | 536 | |
59be0971 AG |
537 | if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) && |
538 | c->stat.nlink > 1) | |
539 | indexed = true; | |
540 | ||
541 | if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed) | |
542 | c->origin = true; | |
543 | ||
544 | if (indexed) { | |
545 | c->destdir = ovl_indexdir(c->dentry->d_sb); | |
546 | err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); | |
547 | if (err) | |
548 | return err; | |
549 | } else { | |
550 | /* | |
551 | * Mark parent "impure" because it may now contain non-pure | |
552 | * upper | |
553 | */ | |
554 | err = ovl_set_impure(c->parent, c->destdir); | |
555 | if (err) | |
556 | return err; | |
557 | } | |
e9be9d5e | 558 | |
01ad3eb8 | 559 | /* Should we copyup with O_TMPFILE or with workdir? */ |
23f0ab13 | 560 | if (S_ISREG(c->stat.mode) && ofs->tmpfile) { |
23f0ab13 | 561 | c->tmpfile = true; |
59be0971 AG |
562 | err = ovl_copy_up_locked(c); |
563 | } else { | |
564 | err = -EIO; | |
565 | if (lock_rename(c->workdir, c->destdir) != NULL) { | |
566 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
567 | } else { | |
568 | err = ovl_copy_up_locked(c); | |
569 | unlock_rename(c->workdir, c->destdir); | |
570 | } | |
01ad3eb8 AG |
571 | } |
572 | ||
59be0971 AG |
573 | if (indexed) { |
574 | if (!err) | |
575 | ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); | |
576 | kfree(c->destname.name); | |
577 | } else if (!err) { | |
578 | struct inode *udir = d_inode(c->destdir); | |
579 | ||
580 | /* Restore timestamps on parent (best effort) */ | |
581 | inode_lock(udir); | |
582 | ovl_set_timestamps(c->destdir, &c->pstat); | |
583 | inode_unlock(udir); | |
584 | ||
585 | ovl_dentry_set_upper_alias(c->dentry); | |
e9be9d5e MS |
586 | } |
587 | ||
a6fb235a MS |
588 | return err; |
589 | } | |
590 | ||
591 | static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, | |
592 | int flags) | |
593 | { | |
594 | int err; | |
595 | DEFINE_DELAYED_CALL(done); | |
596 | struct path parentpath; | |
597 | struct ovl_copy_up_ctx ctx = { | |
598 | .parent = parent, | |
599 | .dentry = dentry, | |
600 | .workdir = ovl_workdir(dentry), | |
601 | }; | |
602 | ||
603 | if (WARN_ON(!ctx.workdir)) | |
604 | return -EROFS; | |
605 | ||
606 | ovl_path_lower(dentry, &ctx.lowerpath); | |
607 | err = vfs_getattr(&ctx.lowerpath, &ctx.stat, | |
608 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
609 | if (err) | |
610 | return err; | |
611 | ||
612 | ovl_path_upper(parent, &parentpath); | |
59be0971 AG |
613 | ctx.destdir = parentpath.dentry; |
614 | ctx.destname = dentry->d_name; | |
a6fb235a MS |
615 | |
616 | err = vfs_getattr(&parentpath, &ctx.pstat, | |
617 | STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); | |
618 | if (err) | |
619 | return err; | |
620 | ||
621 | /* maybe truncate regular file. this has no effect on dirs */ | |
622 | if (flags & O_TRUNC) | |
623 | ctx.stat.size = 0; | |
624 | ||
625 | if (S_ISLNK(ctx.stat.mode)) { | |
626 | ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); | |
627 | if (IS_ERR(ctx.link)) | |
628 | return PTR_ERR(ctx.link); | |
629 | } | |
630 | ovl_do_check_copy_up(ctx.lowerpath.dentry); | |
631 | ||
fd210b7d MS |
632 | err = ovl_copy_up_start(dentry); |
633 | /* err < 0: interrupted, err > 0: raced with another copy-up */ | |
634 | if (unlikely(err)) { | |
635 | if (err > 0) | |
636 | err = 0; | |
637 | } else { | |
59be0971 AG |
638 | if (!ovl_dentry_upper(dentry)) |
639 | err = ovl_do_copy_up(&ctx); | |
640 | if (!err && !ovl_dentry_has_upper_alias(dentry)) | |
f4439de1 | 641 | err = ovl_link_up(&ctx); |
fd210b7d MS |
642 | ovl_copy_up_end(dentry); |
643 | } | |
7764235b | 644 | do_delayed_call(&done); |
e9be9d5e MS |
645 | |
646 | return err; | |
647 | } | |
648 | ||
9aba6521 | 649 | int ovl_copy_up_flags(struct dentry *dentry, int flags) |
e9be9d5e | 650 | { |
8eac98b8 VG |
651 | int err = 0; |
652 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); | |
e9be9d5e | 653 | |
e9be9d5e MS |
654 | while (!err) { |
655 | struct dentry *next; | |
656 | struct dentry *parent; | |
e9be9d5e | 657 | |
59be0971 AG |
658 | /* |
659 | * Check if copy-up has happened as well as for upper alias (in | |
660 | * case of hard links) is there. | |
661 | * | |
662 | * Both checks are lockless: | |
663 | * - false negatives: will recheck under oi->lock | |
664 | * - false positives: | |
665 | * + ovl_dentry_upper() uses memory barriers to ensure the | |
666 | * upper dentry is up-to-date | |
667 | * + ovl_dentry_has_upper_alias() relies on locking of | |
668 | * upper parent i_rwsem to prevent reordering copy-up | |
669 | * with rename. | |
670 | */ | |
671 | if (ovl_dentry_upper(dentry) && | |
672 | ovl_dentry_has_upper_alias(dentry)) | |
e9be9d5e MS |
673 | break; |
674 | ||
675 | next = dget(dentry); | |
676 | /* find the topmost dentry not yet copied up */ | |
677 | for (;;) { | |
678 | parent = dget_parent(next); | |
679 | ||
59be0971 | 680 | if (ovl_dentry_upper(parent)) |
e9be9d5e MS |
681 | break; |
682 | ||
683 | dput(next); | |
684 | next = parent; | |
685 | } | |
686 | ||
a6fb235a | 687 | err = ovl_copy_up_one(parent, next, flags); |
e9be9d5e MS |
688 | |
689 | dput(parent); | |
690 | dput(next); | |
691 | } | |
8eac98b8 | 692 | revert_creds(old_cred); |
e9be9d5e MS |
693 | |
694 | return err; | |
695 | } | |
9aba6521 AG |
696 | |
697 | int ovl_copy_up(struct dentry *dentry) | |
698 | { | |
699 | return ovl_copy_up_flags(dentry, 0); | |
700 | } |