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 MS |
24 | #include "overlayfs.h" |
25 | ||
26 | #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) | |
27 | ||
fb5bb2c3 DH |
28 | static bool __read_mostly ovl_check_copy_up; |
29 | module_param_named(check_copy_up, ovl_check_copy_up, bool, | |
30 | S_IWUSR | S_IRUGO); | |
31 | MODULE_PARM_DESC(ovl_check_copy_up, | |
32 | "Warn on copy-up when causing process also has a R/O fd open"); | |
33 | ||
34 | static int ovl_check_fd(const void *data, struct file *f, unsigned int fd) | |
35 | { | |
36 | const struct dentry *dentry = data; | |
37 | ||
45063097 | 38 | if (file_inode(f) == d_inode(dentry)) |
fb5bb2c3 DH |
39 | 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", |
40 | f, fd, current->pid, current->comm); | |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* | |
45 | * Check the fds open by this process and warn if something like the following | |
46 | * scenario is about to occur: | |
47 | * | |
48 | * fd1 = open("foo", O_RDONLY); | |
49 | * fd2 = open("foo", O_RDWR); | |
50 | */ | |
51 | static void ovl_do_check_copy_up(struct dentry *dentry) | |
52 | { | |
53 | if (ovl_check_copy_up) | |
54 | iterate_fd(current->files, 0, ovl_check_fd, dentry); | |
55 | } | |
56 | ||
e9be9d5e MS |
57 | int ovl_copy_xattr(struct dentry *old, struct dentry *new) |
58 | { | |
e4ad29fa VC |
59 | ssize_t list_size, size, value_size = 0; |
60 | char *buf, *name, *value = NULL; | |
61 | int uninitialized_var(error); | |
8b326c61 | 62 | size_t slen; |
e9be9d5e | 63 | |
5d6c3191 AG |
64 | if (!(old->d_inode->i_opflags & IOP_XATTR) || |
65 | !(new->d_inode->i_opflags & IOP_XATTR)) | |
e9be9d5e MS |
66 | return 0; |
67 | ||
68 | list_size = vfs_listxattr(old, NULL, 0); | |
69 | if (list_size <= 0) { | |
70 | if (list_size == -EOPNOTSUPP) | |
71 | return 0; | |
72 | return list_size; | |
73 | } | |
74 | ||
75 | buf = kzalloc(list_size, GFP_KERNEL); | |
76 | if (!buf) | |
77 | return -ENOMEM; | |
78 | ||
e9be9d5e MS |
79 | list_size = vfs_listxattr(old, buf, list_size); |
80 | if (list_size <= 0) { | |
81 | error = list_size; | |
e4ad29fa | 82 | goto out; |
e9be9d5e MS |
83 | } |
84 | ||
8b326c61 MS |
85 | for (name = buf; list_size; name += slen) { |
86 | slen = strnlen(name, list_size) + 1; | |
87 | ||
88 | /* underlying fs providing us with an broken xattr list? */ | |
89 | if (WARN_ON(slen > list_size)) { | |
90 | error = -EIO; | |
91 | break; | |
92 | } | |
93 | list_size -= slen; | |
94 | ||
0956254a MS |
95 | if (ovl_is_private_xattr(name)) |
96 | continue; | |
e4ad29fa VC |
97 | retry: |
98 | size = vfs_getxattr(old, name, value, value_size); | |
99 | if (size == -ERANGE) | |
100 | size = vfs_getxattr(old, name, NULL, 0); | |
101 | ||
97daf8b9 | 102 | if (size < 0) { |
e9be9d5e | 103 | error = size; |
e4ad29fa | 104 | break; |
e9be9d5e | 105 | } |
e4ad29fa VC |
106 | |
107 | if (size > value_size) { | |
108 | void *new; | |
109 | ||
110 | new = krealloc(value, size, GFP_KERNEL); | |
111 | if (!new) { | |
112 | error = -ENOMEM; | |
113 | break; | |
114 | } | |
115 | value = new; | |
116 | value_size = size; | |
117 | goto retry; | |
118 | } | |
119 | ||
121ab822 VG |
120 | error = security_inode_copy_up_xattr(name); |
121 | if (error < 0 && error != -EOPNOTSUPP) | |
122 | break; | |
123 | if (error == 1) { | |
124 | error = 0; | |
125 | continue; /* Discard */ | |
126 | } | |
e9be9d5e MS |
127 | error = vfs_setxattr(new, name, value, size, 0); |
128 | if (error) | |
e4ad29fa | 129 | break; |
e9be9d5e | 130 | } |
e9be9d5e MS |
131 | kfree(value); |
132 | out: | |
133 | kfree(buf); | |
134 | return error; | |
135 | } | |
136 | ||
137 | static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) | |
138 | { | |
139 | struct file *old_file; | |
140 | struct file *new_file; | |
141 | loff_t old_pos = 0; | |
142 | loff_t new_pos = 0; | |
143 | int error = 0; | |
144 | ||
145 | if (len == 0) | |
146 | return 0; | |
147 | ||
0480334f | 148 | old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); |
e9be9d5e MS |
149 | if (IS_ERR(old_file)) |
150 | return PTR_ERR(old_file); | |
151 | ||
0480334f | 152 | new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); |
e9be9d5e MS |
153 | if (IS_ERR(new_file)) { |
154 | error = PTR_ERR(new_file); | |
155 | goto out_fput; | |
156 | } | |
157 | ||
2ea98466 AG |
158 | /* Try to use clone_file_range to clone up within the same fs */ |
159 | error = vfs_clone_file_range(old_file, 0, new_file, 0, len); | |
160 | if (!error) | |
161 | goto out; | |
162 | /* Couldn't clone, so now we try to copy the data */ | |
163 | error = 0; | |
164 | ||
e9be9d5e MS |
165 | /* FIXME: copy up sparse files efficiently */ |
166 | while (len) { | |
167 | size_t this_len = OVL_COPY_UP_CHUNK_SIZE; | |
168 | long bytes; | |
169 | ||
170 | if (len < this_len) | |
171 | this_len = len; | |
172 | ||
173 | if (signal_pending_state(TASK_KILLABLE, current)) { | |
174 | error = -EINTR; | |
175 | break; | |
176 | } | |
177 | ||
178 | bytes = do_splice_direct(old_file, &old_pos, | |
179 | new_file, &new_pos, | |
180 | this_len, SPLICE_F_MOVE); | |
181 | if (bytes <= 0) { | |
182 | error = bytes; | |
183 | break; | |
184 | } | |
185 | WARN_ON(old_pos != new_pos); | |
186 | ||
187 | len -= bytes; | |
188 | } | |
2ea98466 | 189 | out: |
641089c1 MS |
190 | if (!error) |
191 | error = vfs_fsync(new_file, 0); | |
e9be9d5e MS |
192 | fput(new_file); |
193 | out_fput: | |
194 | fput(old_file); | |
195 | return error; | |
196 | } | |
197 | ||
e9be9d5e MS |
198 | static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) |
199 | { | |
200 | struct iattr attr = { | |
201 | .ia_valid = | |
202 | ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, | |
203 | .ia_atime = stat->atime, | |
204 | .ia_mtime = stat->mtime, | |
205 | }; | |
206 | ||
207 | return notify_change(upperdentry, &attr, NULL); | |
208 | } | |
209 | ||
210 | int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) | |
211 | { | |
212 | int err = 0; | |
213 | ||
214 | if (!S_ISLNK(stat->mode)) { | |
215 | struct iattr attr = { | |
216 | .ia_valid = ATTR_MODE, | |
217 | .ia_mode = stat->mode, | |
218 | }; | |
219 | err = notify_change(upperdentry, &attr, NULL); | |
220 | } | |
221 | if (!err) { | |
222 | struct iattr attr = { | |
223 | .ia_valid = ATTR_UID | ATTR_GID, | |
224 | .ia_uid = stat->uid, | |
225 | .ia_gid = stat->gid, | |
226 | }; | |
227 | err = notify_change(upperdentry, &attr, NULL); | |
228 | } | |
229 | if (!err) | |
230 | ovl_set_timestamps(upperdentry, stat); | |
231 | ||
232 | return err; | |
e9be9d5e MS |
233 | } |
234 | ||
54fb347e | 235 | struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper) |
3a1e819b AG |
236 | { |
237 | struct ovl_fh *fh; | |
238 | int fh_type, fh_len, dwords; | |
239 | void *buf; | |
240 | int buflen = MAX_HANDLE_SZ; | |
02bcd157 | 241 | uuid_t *uuid = &lower->d_sb->s_uuid; |
3a1e819b | 242 | |
0ee931c4 | 243 | buf = kmalloc(buflen, GFP_KERNEL); |
3a1e819b AG |
244 | if (!buf) |
245 | return ERR_PTR(-ENOMEM); | |
246 | ||
247 | /* | |
248 | * We encode a non-connectable file handle for non-dir, because we | |
249 | * only need to find the lower inode number and we don't want to pay | |
250 | * the price or reconnecting the dentry. | |
251 | */ | |
252 | dwords = buflen >> 2; | |
253 | fh_type = exportfs_encode_fh(lower, buf, &dwords, 0); | |
254 | buflen = (dwords << 2); | |
255 | ||
256 | fh = ERR_PTR(-EIO); | |
257 | if (WARN_ON(fh_type < 0) || | |
258 | WARN_ON(buflen > MAX_HANDLE_SZ) || | |
259 | WARN_ON(fh_type == FILEID_INVALID)) | |
260 | goto out; | |
261 | ||
262 | BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255); | |
263 | fh_len = offsetof(struct ovl_fh, fid) + buflen; | |
264 | fh = kmalloc(fh_len, GFP_KERNEL); | |
265 | if (!fh) { | |
266 | fh = ERR_PTR(-ENOMEM); | |
267 | goto out; | |
268 | } | |
269 | ||
270 | fh->version = OVL_FH_VERSION; | |
271 | fh->magic = OVL_FH_MAGIC; | |
272 | fh->type = fh_type; | |
273 | fh->flags = OVL_FH_FLAG_CPU_ENDIAN; | |
54fb347e AG |
274 | /* |
275 | * When we will want to decode an overlay dentry from this handle | |
276 | * and all layers are on the same fs, if we get a disconncted real | |
277 | * dentry when we decode fid, the only way to tell if we should assign | |
278 | * it to upperdentry or to lowerstack is by checking this flag. | |
279 | */ | |
280 | if (is_upper) | |
281 | fh->flags |= OVL_FH_FLAG_PATH_UPPER; | |
3a1e819b AG |
282 | fh->len = fh_len; |
283 | fh->uuid = *uuid; | |
284 | memcpy(fh->fid, buf, buflen); | |
285 | ||
286 | out: | |
287 | kfree(buf); | |
288 | return fh; | |
289 | } | |
290 | ||
9678e630 AG |
291 | int ovl_set_origin(struct dentry *dentry, struct dentry *lower, |
292 | struct dentry *upper) | |
3a1e819b | 293 | { |
3a1e819b AG |
294 | const struct ovl_fh *fh = NULL; |
295 | int err; | |
296 | ||
297 | /* | |
298 | * When lower layer doesn't support export operations store a 'null' fh, | |
299 | * so we can use the overlay.origin xattr to distignuish between a copy | |
300 | * up and a pure upper inode. | |
301 | */ | |
02bcd157 | 302 | if (ovl_can_decode_fh(lower->d_sb)) { |
54fb347e | 303 | fh = ovl_encode_fh(lower, false); |
3a1e819b AG |
304 | if (IS_ERR(fh)) |
305 | return PTR_ERR(fh); | |
306 | } | |
307 | ||
6266d465 MS |
308 | /* |
309 | * Do not fail when upper doesn't support xattrs. | |
310 | */ | |
311 | err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh, | |
312 | fh ? fh->len : 0, 0); | |
3a1e819b AG |
313 | kfree(fh); |
314 | ||
315 | return err; | |
316 | } | |
317 | ||
f4439de1 AG |
318 | struct ovl_copy_up_ctx { |
319 | struct dentry *parent; | |
320 | struct dentry *dentry; | |
321 | struct path lowerpath; | |
322 | struct kstat stat; | |
323 | struct kstat pstat; | |
324 | const char *link; | |
325 | struct dentry *destdir; | |
326 | struct qstr destname; | |
327 | struct dentry *workdir; | |
328 | bool tmpfile; | |
329 | bool origin; | |
330 | }; | |
331 | ||
332 | static int ovl_link_up(struct ovl_copy_up_ctx *c) | |
59be0971 AG |
333 | { |
334 | int err; | |
335 | struct dentry *upper; | |
f4439de1 | 336 | struct dentry *upperdir = ovl_dentry_upper(c->parent); |
59be0971 AG |
337 | struct inode *udir = d_inode(upperdir); |
338 | ||
f4439de1 AG |
339 | /* Mark parent "impure" because it may now contain non-pure upper */ |
340 | err = ovl_set_impure(c->parent, upperdir); | |
341 | if (err) | |
342 | return err; | |
343 | ||
344 | err = ovl_set_nlink_lower(c->dentry); | |
5f8415d6 AG |
345 | if (err) |
346 | return err; | |
347 | ||
59be0971 | 348 | inode_lock_nested(udir, I_MUTEX_PARENT); |
f4439de1 AG |
349 | upper = lookup_one_len(c->dentry->d_name.name, upperdir, |
350 | c->dentry->d_name.len); | |
59be0971 AG |
351 | err = PTR_ERR(upper); |
352 | if (!IS_ERR(upper)) { | |
f4439de1 AG |
353 | err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper, |
354 | true); | |
59be0971 AG |
355 | dput(upper); |
356 | ||
f4439de1 AG |
357 | if (!err) { |
358 | /* Restore timestamps on parent (best effort) */ | |
359 | ovl_set_timestamps(upperdir, &c->pstat); | |
360 | ovl_dentry_set_upper_alias(c->dentry); | |
361 | } | |
59be0971 AG |
362 | } |
363 | inode_unlock(udir); | |
f4439de1 | 364 | ovl_set_nlink_upper(c->dentry); |
59be0971 AG |
365 | |
366 | return err; | |
367 | } | |
368 | ||
23f0ab13 MS |
369 | static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp, |
370 | struct dentry **newdentry) | |
15932c41 AG |
371 | { |
372 | int err; | |
373 | struct dentry *upper; | |
59be0971 | 374 | struct inode *udir = d_inode(c->destdir); |
15932c41 | 375 | |
59be0971 | 376 | upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len); |
15932c41 AG |
377 | if (IS_ERR(upper)) |
378 | return PTR_ERR(upper); | |
379 | ||
23f0ab13 | 380 | if (c->tmpfile) |
15932c41 AG |
381 | err = ovl_do_link(temp, udir, upper, true); |
382 | else | |
23f0ab13 | 383 | err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0); |
15932c41 | 384 | |
59be0971 | 385 | if (!err) |
23f0ab13 | 386 | *newdentry = dget(c->tmpfile ? upper : temp); |
15932c41 AG |
387 | dput(upper); |
388 | ||
389 | return err; | |
390 | } | |
391 | ||
23f0ab13 | 392 | static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp) |
e9be9d5e | 393 | { |
e9be9d5e | 394 | int err; |
7d90b853 | 395 | struct dentry *temp; |
d8ad8b49 VG |
396 | const struct cred *old_creds = NULL; |
397 | struct cred *new_creds = NULL; | |
32a3d848 AV |
398 | struct cattr cattr = { |
399 | /* Can't properly set mode on creation because of the umask */ | |
23f0ab13 MS |
400 | .mode = c->stat.mode & S_IFMT, |
401 | .rdev = c->stat.rdev, | |
402 | .link = c->link | |
32a3d848 | 403 | }; |
e9be9d5e | 404 | |
23f0ab13 | 405 | err = security_inode_copy_up(c->dentry, &new_creds); |
d8ad8b49 | 406 | if (err < 0) |
e85f82ff | 407 | goto out; |
d8ad8b49 VG |
408 | |
409 | if (new_creds) | |
410 | old_creds = override_creds(new_creds); | |
411 | ||
23f0ab13 MS |
412 | if (c->tmpfile) { |
413 | temp = ovl_do_tmpfile(c->workdir, c->stat.mode); | |
7d90b853 MS |
414 | if (IS_ERR(temp)) |
415 | goto temp_err; | |
416 | } else { | |
23f0ab13 | 417 | temp = ovl_lookup_temp(c->workdir); |
7d90b853 MS |
418 | if (IS_ERR(temp)) |
419 | goto temp_err; | |
420 | ||
23f0ab13 | 421 | err = ovl_create_real(d_inode(c->workdir), temp, &cattr, |
7d90b853 MS |
422 | NULL, true); |
423 | if (err) { | |
424 | dput(temp); | |
425 | goto out; | |
426 | } | |
8137ae26 | 427 | } |
7d90b853 MS |
428 | err = 0; |
429 | *tempp = temp; | |
430 | out: | |
d8ad8b49 VG |
431 | if (new_creds) { |
432 | revert_creds(old_creds); | |
433 | put_cred(new_creds); | |
434 | } | |
435 | ||
7d90b853 MS |
436 | return err; |
437 | ||
438 | temp_err: | |
439 | err = PTR_ERR(temp); | |
440 | goto out; | |
441 | } | |
442 | ||
23f0ab13 | 443 | static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) |
7d90b853 | 444 | { |
7d90b853 MS |
445 | int err; |
446 | ||
23f0ab13 | 447 | if (S_ISREG(c->stat.mode)) { |
e9be9d5e | 448 | struct path upperpath; |
f134f244 | 449 | |
23f0ab13 | 450 | ovl_path_upper(c->dentry, &upperpath); |
e9be9d5e | 451 | BUG_ON(upperpath.dentry != NULL); |
42f269b9 | 452 | upperpath.dentry = temp; |
e9be9d5e | 453 | |
23f0ab13 | 454 | err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size); |
e9be9d5e | 455 | if (err) |
02209d10 | 456 | return err; |
e9be9d5e MS |
457 | } |
458 | ||
23f0ab13 | 459 | err = ovl_copy_xattr(c->lowerpath.dentry, temp); |
e9be9d5e | 460 | if (err) |
02209d10 | 461 | return err; |
e9be9d5e | 462 | |
42f269b9 | 463 | inode_lock(temp->d_inode); |
23f0ab13 | 464 | err = ovl_set_attr(temp, &c->stat); |
42f269b9 | 465 | inode_unlock(temp->d_inode); |
e9be9d5e | 466 | if (err) |
02209d10 | 467 | return err; |
e9be9d5e | 468 | |
3a1e819b AG |
469 | /* |
470 | * Store identifier of lower inode in upper inode xattr to | |
471 | * allow lookup of the copy up origin inode. | |
fbaf94ee MS |
472 | * |
473 | * Don't set origin when we are breaking the association with a lower | |
474 | * hard link. | |
3a1e819b | 475 | */ |
59be0971 | 476 | if (c->origin) { |
23f0ab13 | 477 | err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp); |
fbaf94ee | 478 | if (err) |
02209d10 | 479 | return err; |
fbaf94ee | 480 | } |
3a1e819b | 481 | |
02209d10 AG |
482 | return 0; |
483 | } | |
484 | ||
23f0ab13 | 485 | static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c) |
02209d10 | 486 | { |
59be0971 | 487 | struct inode *udir = c->destdir->d_inode; |
b79e05aa | 488 | struct inode *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 | ||
b79e05aa AG |
511 | inode = d_inode(c->dentry); |
512 | ovl_inode_update(inode, newdentry); | |
513 | if (S_ISDIR(inode->i_mode)) | |
514 | ovl_set_flag(OVL_WHITEOUTS, inode); | |
515 | ||
e85f82ff | 516 | out: |
42f269b9 | 517 | dput(temp); |
e9be9d5e MS |
518 | return err; |
519 | ||
520 | out_cleanup: | |
23f0ab13 MS |
521 | if (!c->tmpfile) |
522 | ovl_cleanup(d_inode(c->workdir), temp); | |
e85f82ff | 523 | goto out; |
e9be9d5e MS |
524 | } |
525 | ||
526 | /* | |
527 | * Copy up a single dentry | |
528 | * | |
a6c60655 MS |
529 | * All renames start with copy up of source if necessary. The actual |
530 | * rename will only proceed once the copy up was successful. Copy up uses | |
531 | * upper parent i_mutex for exclusion. Since rename can change d_parent it | |
532 | * is possible that the copy up will lock the old parent. At that point | |
533 | * the file will have already been copied up anyway. | |
e9be9d5e | 534 | */ |
a6fb235a | 535 | static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) |
e9be9d5e | 536 | { |
e9be9d5e | 537 | int err; |
23f0ab13 | 538 | struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; |
59be0971 | 539 | bool indexed = false; |
e9be9d5e | 540 | |
59be0971 AG |
541 | if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) && |
542 | c->stat.nlink > 1) | |
543 | indexed = true; | |
544 | ||
545 | if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed) | |
546 | c->origin = true; | |
547 | ||
548 | if (indexed) { | |
549 | c->destdir = ovl_indexdir(c->dentry->d_sb); | |
550 | err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); | |
551 | if (err) | |
552 | return err; | |
553 | } else { | |
554 | /* | |
555 | * Mark parent "impure" because it may now contain non-pure | |
556 | * upper | |
557 | */ | |
558 | err = ovl_set_impure(c->parent, c->destdir); | |
559 | if (err) | |
560 | return err; | |
561 | } | |
e9be9d5e | 562 | |
01ad3eb8 | 563 | /* Should we copyup with O_TMPFILE or with workdir? */ |
23f0ab13 | 564 | if (S_ISREG(c->stat.mode) && ofs->tmpfile) { |
23f0ab13 | 565 | c->tmpfile = true; |
59be0971 AG |
566 | err = ovl_copy_up_locked(c); |
567 | } else { | |
5820dc08 AG |
568 | err = ovl_lock_rename_workdir(c->workdir, c->destdir); |
569 | if (!err) { | |
59be0971 AG |
570 | err = ovl_copy_up_locked(c); |
571 | unlock_rename(c->workdir, c->destdir); | |
572 | } | |
01ad3eb8 AG |
573 | } |
574 | ||
59be0971 AG |
575 | if (indexed) { |
576 | if (!err) | |
577 | ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); | |
578 | kfree(c->destname.name); | |
579 | } else if (!err) { | |
580 | struct inode *udir = d_inode(c->destdir); | |
581 | ||
582 | /* Restore timestamps on parent (best effort) */ | |
583 | inode_lock(udir); | |
584 | ovl_set_timestamps(c->destdir, &c->pstat); | |
585 | inode_unlock(udir); | |
586 | ||
587 | ovl_dentry_set_upper_alias(c->dentry); | |
e9be9d5e MS |
588 | } |
589 | ||
a6fb235a MS |
590 | return err; |
591 | } | |
592 | ||
593 | static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, | |
594 | int flags) | |
595 | { | |
596 | int err; | |
597 | DEFINE_DELAYED_CALL(done); | |
598 | struct path parentpath; | |
599 | struct ovl_copy_up_ctx ctx = { | |
600 | .parent = parent, | |
601 | .dentry = dentry, | |
602 | .workdir = ovl_workdir(dentry), | |
603 | }; | |
604 | ||
605 | if (WARN_ON(!ctx.workdir)) | |
606 | return -EROFS; | |
607 | ||
608 | ovl_path_lower(dentry, &ctx.lowerpath); | |
609 | err = vfs_getattr(&ctx.lowerpath, &ctx.stat, | |
610 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
611 | if (err) | |
612 | return err; | |
613 | ||
614 | ovl_path_upper(parent, &parentpath); | |
59be0971 AG |
615 | ctx.destdir = parentpath.dentry; |
616 | ctx.destname = dentry->d_name; | |
a6fb235a MS |
617 | |
618 | err = vfs_getattr(&parentpath, &ctx.pstat, | |
619 | STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); | |
620 | if (err) | |
621 | return err; | |
622 | ||
623 | /* maybe truncate regular file. this has no effect on dirs */ | |
624 | if (flags & O_TRUNC) | |
625 | ctx.stat.size = 0; | |
626 | ||
627 | if (S_ISLNK(ctx.stat.mode)) { | |
628 | ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); | |
629 | if (IS_ERR(ctx.link)) | |
630 | return PTR_ERR(ctx.link); | |
631 | } | |
632 | ovl_do_check_copy_up(ctx.lowerpath.dentry); | |
633 | ||
fd210b7d MS |
634 | err = ovl_copy_up_start(dentry); |
635 | /* err < 0: interrupted, err > 0: raced with another copy-up */ | |
636 | if (unlikely(err)) { | |
637 | if (err > 0) | |
638 | err = 0; | |
639 | } else { | |
59be0971 AG |
640 | if (!ovl_dentry_upper(dentry)) |
641 | err = ovl_do_copy_up(&ctx); | |
642 | if (!err && !ovl_dentry_has_upper_alias(dentry)) | |
f4439de1 | 643 | err = ovl_link_up(&ctx); |
fd210b7d MS |
644 | ovl_copy_up_end(dentry); |
645 | } | |
7764235b | 646 | do_delayed_call(&done); |
e9be9d5e MS |
647 | |
648 | return err; | |
649 | } | |
650 | ||
9aba6521 | 651 | int ovl_copy_up_flags(struct dentry *dentry, int flags) |
e9be9d5e | 652 | { |
8eac98b8 VG |
653 | int err = 0; |
654 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); | |
e9be9d5e | 655 | |
e9be9d5e MS |
656 | while (!err) { |
657 | struct dentry *next; | |
658 | struct dentry *parent; | |
e9be9d5e | 659 | |
59be0971 AG |
660 | /* |
661 | * Check if copy-up has happened as well as for upper alias (in | |
662 | * case of hard links) is there. | |
663 | * | |
664 | * Both checks are lockless: | |
665 | * - false negatives: will recheck under oi->lock | |
666 | * - false positives: | |
667 | * + ovl_dentry_upper() uses memory barriers to ensure the | |
668 | * upper dentry is up-to-date | |
669 | * + ovl_dentry_has_upper_alias() relies on locking of | |
670 | * upper parent i_rwsem to prevent reordering copy-up | |
671 | * with rename. | |
672 | */ | |
673 | if (ovl_dentry_upper(dentry) && | |
674 | ovl_dentry_has_upper_alias(dentry)) | |
e9be9d5e MS |
675 | break; |
676 | ||
677 | next = dget(dentry); | |
678 | /* find the topmost dentry not yet copied up */ | |
679 | for (;;) { | |
680 | parent = dget_parent(next); | |
681 | ||
59be0971 | 682 | if (ovl_dentry_upper(parent)) |
e9be9d5e MS |
683 | break; |
684 | ||
685 | dput(next); | |
686 | next = parent; | |
687 | } | |
688 | ||
a6fb235a | 689 | err = ovl_copy_up_one(parent, next, flags); |
e9be9d5e MS |
690 | |
691 | dput(parent); | |
692 | dput(next); | |
693 | } | |
8eac98b8 | 694 | revert_creds(old_cred); |
e9be9d5e MS |
695 | |
696 | return err; | |
697 | } | |
9aba6521 AG |
698 | |
699 | int ovl_copy_up(struct dentry *dentry) | |
700 | { | |
701 | return ovl_copy_up_flags(dentry, 0); | |
702 | } |