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1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7*/
8
9#include "fuse_i.h"
10
11#include <linux/pagemap.h>
12#include <linux/file.h>
13#include <linux/sched.h>
14#include <linux/namei.h>
15#include <linux/slab.h>
16
17#if BITS_PER_LONG >= 64
18static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
19{
20 entry->d_time = time;
21}
22
23static inline u64 fuse_dentry_time(struct dentry *entry)
24{
25 return entry->d_time;
26}
27#else
28/*
29 * On 32 bit archs store the high 32 bits of time in d_fsdata
30 */
31static void fuse_dentry_settime(struct dentry *entry, u64 time)
32{
33 entry->d_time = time;
34 entry->d_fsdata = (void *) (unsigned long) (time >> 32);
35}
36
37static u64 fuse_dentry_time(struct dentry *entry)
38{
39 return (u64) entry->d_time +
40 ((u64) (unsigned long) entry->d_fsdata << 32);
41}
42#endif
43
44/*
45 * FUSE caches dentries and attributes with separate timeout. The
46 * time in jiffies until the dentry/attributes are valid is stored in
47 * dentry->d_time and fuse_inode->i_time respectively.
48 */
49
50/*
51 * Calculate the time in jiffies until a dentry/attributes are valid
52 */
53static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)
54{
55 if (sec || nsec) {
56 struct timespec ts = {sec, nsec};
57 return get_jiffies_64() + timespec_to_jiffies(&ts);
58 } else
59 return 0;
60}
61
62/*
63 * Set dentry and possibly attribute timeouts from the lookup/mk*
64 * replies
65 */
66static void fuse_change_entry_timeout(struct dentry *entry,
67 struct fuse_entry_out *o)
68{
69 fuse_dentry_settime(entry,
70 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
71}
72
73static u64 attr_timeout(struct fuse_attr_out *o)
74{
75 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
76}
77
78static u64 entry_attr_timeout(struct fuse_entry_out *o)
79{
80 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
81}
82
83/*
84 * Mark the attributes as stale, so that at the next call to
85 * ->getattr() they will be fetched from userspace
86 */
87void fuse_invalidate_attr(struct inode *inode)
88{
89 get_fuse_inode(inode)->i_time = 0;
90}
91
92/*
93 * Just mark the entry as stale, so that a next attempt to look it up
94 * will result in a new lookup call to userspace
95 *
96 * This is called when a dentry is about to become negative and the
97 * timeout is unknown (unlink, rmdir, rename and in some cases
98 * lookup)
99 */
100void fuse_invalidate_entry_cache(struct dentry *entry)
101{
102 fuse_dentry_settime(entry, 0);
103}
104
105/*
106 * Same as fuse_invalidate_entry_cache(), but also try to remove the
107 * dentry from the hash
108 */
109static void fuse_invalidate_entry(struct dentry *entry)
110{
111 d_invalidate(entry);
112 fuse_invalidate_entry_cache(entry);
113}
114
115static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
116 u64 nodeid, struct qstr *name,
117 struct fuse_entry_out *outarg)
118{
119 memset(outarg, 0, sizeof(struct fuse_entry_out));
120 req->in.h.opcode = FUSE_LOOKUP;
121 req->in.h.nodeid = nodeid;
122 req->in.numargs = 1;
123 req->in.args[0].size = name->len + 1;
124 req->in.args[0].value = name->name;
125 req->out.numargs = 1;
126 if (fc->minor < 9)
127 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
128 else
129 req->out.args[0].size = sizeof(struct fuse_entry_out);
130 req->out.args[0].value = outarg;
131}
132
133u64 fuse_get_attr_version(struct fuse_conn *fc)
134{
135 u64 curr_version;
136
137 /*
138 * The spin lock isn't actually needed on 64bit archs, but we
139 * don't yet care too much about such optimizations.
140 */
141 spin_lock(&fc->lock);
142 curr_version = fc->attr_version;
143 spin_unlock(&fc->lock);
144
145 return curr_version;
146}
147
148/*
149 * Check whether the dentry is still valid
150 *
151 * If the entry validity timeout has expired and the dentry is
152 * positive, try to redo the lookup. If the lookup results in a
153 * different inode, then let the VFS invalidate the dentry and redo
154 * the lookup once more. If the lookup results in the same inode,
155 * then refresh the attributes, timeouts and mark the dentry valid.
156 */
157static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
158{
159 struct inode *inode;
160
161 inode = ACCESS_ONCE(entry->d_inode);
162 if (inode && is_bad_inode(inode))
163 return 0;
164 else if (fuse_dentry_time(entry) < get_jiffies_64()) {
165 int err;
166 struct fuse_entry_out outarg;
167 struct fuse_conn *fc;
168 struct fuse_req *req;
169 struct fuse_forget_link *forget;
170 struct dentry *parent;
171 u64 attr_version;
172
173 /* For negative dentries, always do a fresh lookup */
174 if (!inode)
175 return 0;
176
177 if (nd && (nd->flags & LOOKUP_RCU))
178 return -ECHILD;
179
180 fc = get_fuse_conn(inode);
181 req = fuse_get_req(fc);
182 if (IS_ERR(req))
183 return 0;
184
185 forget = fuse_alloc_forget();
186 if (!forget) {
187 fuse_put_request(fc, req);
188 return 0;
189 }
190
191 attr_version = fuse_get_attr_version(fc);
192
193 parent = dget_parent(entry);
194 fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
195 &entry->d_name, &outarg);
196 fuse_request_send(fc, req);
197 dput(parent);
198 err = req->out.h.error;
199 fuse_put_request(fc, req);
200 /* Zero nodeid is same as -ENOENT */
201 if (!err && !outarg.nodeid)
202 err = -ENOENT;
203 if (!err) {
204 struct fuse_inode *fi = get_fuse_inode(inode);
205 if (outarg.nodeid != get_node_id(inode)) {
206 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
207 return 0;
208 }
209 spin_lock(&fc->lock);
210 fi->nlookup++;
211 spin_unlock(&fc->lock);
212 }
213 kfree(forget);
214 if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
215 return 0;
216
217 fuse_change_attributes(inode, &outarg.attr,
218 entry_attr_timeout(&outarg),
219 attr_version);
220 fuse_change_entry_timeout(entry, &outarg);
221 }
222 return 1;
223}
224
225static int invalid_nodeid(u64 nodeid)
226{
227 return !nodeid || nodeid == FUSE_ROOT_ID;
228}
229
230const struct dentry_operations fuse_dentry_operations = {
231 .d_revalidate = fuse_dentry_revalidate,
232};
233
234int fuse_valid_type(int m)
235{
236 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
237 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
238}
239
240/*
241 * Add a directory inode to a dentry, ensuring that no other dentry
242 * refers to this inode. Called with fc->inst_mutex.
243 */
244static struct dentry *fuse_d_add_directory(struct dentry *entry,
245 struct inode *inode)
246{
247 struct dentry *alias = d_find_alias(inode);
248 if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
249 /* This tries to shrink the subtree below alias */
250 fuse_invalidate_entry(alias);
251 dput(alias);
252 if (!list_empty(&inode->i_dentry))
253 return ERR_PTR(-EBUSY);
254 } else {
255 dput(alias);
256 }
257 return d_splice_alias(inode, entry);
258}
259
260int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
261 struct fuse_entry_out *outarg, struct inode **inode)
262{
263 struct fuse_conn *fc = get_fuse_conn_super(sb);
264 struct fuse_req *req;
265 struct fuse_forget_link *forget;
266 u64 attr_version;
267 int err;
268
269 *inode = NULL;
270 err = -ENAMETOOLONG;
271 if (name->len > FUSE_NAME_MAX)
272 goto out;
273
274 req = fuse_get_req(fc);
275 err = PTR_ERR(req);
276 if (IS_ERR(req))
277 goto out;
278
279 forget = fuse_alloc_forget();
280 err = -ENOMEM;
281 if (!forget) {
282 fuse_put_request(fc, req);
283 goto out;
284 }
285
286 attr_version = fuse_get_attr_version(fc);
287
288 fuse_lookup_init(fc, req, nodeid, name, outarg);
289 fuse_request_send(fc, req);
290 err = req->out.h.error;
291 fuse_put_request(fc, req);
292 /* Zero nodeid is same as -ENOENT, but with valid timeout */
293 if (err || !outarg->nodeid)
294 goto out_put_forget;
295
296 err = -EIO;
297 if (!outarg->nodeid)
298 goto out_put_forget;
299 if (!fuse_valid_type(outarg->attr.mode))
300 goto out_put_forget;
301
302 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
303 &outarg->attr, entry_attr_timeout(outarg),
304 attr_version);
305 err = -ENOMEM;
306 if (!*inode) {
307 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
308 goto out;
309 }
310 err = 0;
311
312 out_put_forget:
313 kfree(forget);
314 out:
315 return err;
316}
317
318static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
319 struct nameidata *nd)
320{
321 int err;
322 struct fuse_entry_out outarg;
323 struct inode *inode;
324 struct dentry *newent;
325 struct fuse_conn *fc = get_fuse_conn(dir);
326 bool outarg_valid = true;
327
328 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
329 &outarg, &inode);
330 if (err == -ENOENT) {
331 outarg_valid = false;
332 err = 0;
333 }
334 if (err)
335 goto out_err;
336
337 err = -EIO;
338 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
339 goto out_iput;
340
341 if (inode && S_ISDIR(inode->i_mode)) {
342 mutex_lock(&fc->inst_mutex);
343 newent = fuse_d_add_directory(entry, inode);
344 mutex_unlock(&fc->inst_mutex);
345 err = PTR_ERR(newent);
346 if (IS_ERR(newent))
347 goto out_iput;
348 } else {
349 newent = d_splice_alias(inode, entry);
350 }
351
352 entry = newent ? newent : entry;
353 if (outarg_valid)
354 fuse_change_entry_timeout(entry, &outarg);
355 else
356 fuse_invalidate_entry_cache(entry);
357
358 return newent;
359
360 out_iput:
361 iput(inode);
362 out_err:
363 return ERR_PTR(err);
364}
365
366/*
367 * Atomic create+open operation
368 *
369 * If the filesystem doesn't support this, then fall back to separate
370 * 'mknod' + 'open' requests.
371 */
372static int fuse_create_open(struct inode *dir, struct dentry *entry,
373 umode_t mode, struct nameidata *nd)
374{
375 int err;
376 struct inode *inode;
377 struct fuse_conn *fc = get_fuse_conn(dir);
378 struct fuse_req *req;
379 struct fuse_forget_link *forget;
380 struct fuse_create_in inarg;
381 struct fuse_open_out outopen;
382 struct fuse_entry_out outentry;
383 struct fuse_file *ff;
384 struct file *file;
385 int flags = nd->intent.open.flags;
386
387 if (fc->no_create)
388 return -ENOSYS;
389
390 forget = fuse_alloc_forget();
391 if (!forget)
392 return -ENOMEM;
393
394 req = fuse_get_req(fc);
395 err = PTR_ERR(req);
396 if (IS_ERR(req))
397 goto out_put_forget_req;
398
399 err = -ENOMEM;
400 ff = fuse_file_alloc(fc);
401 if (!ff)
402 goto out_put_request;
403
404 if (!fc->dont_mask)
405 mode &= ~current_umask();
406
407 flags &= ~O_NOCTTY;
408 memset(&inarg, 0, sizeof(inarg));
409 memset(&outentry, 0, sizeof(outentry));
410 inarg.flags = flags;
411 inarg.mode = mode;
412 inarg.umask = current_umask();
413 req->in.h.opcode = FUSE_CREATE;
414 req->in.h.nodeid = get_node_id(dir);
415 req->in.numargs = 2;
416 req->in.args[0].size = fc->minor < 12 ? sizeof(struct fuse_open_in) :
417 sizeof(inarg);
418 req->in.args[0].value = &inarg;
419 req->in.args[1].size = entry->d_name.len + 1;
420 req->in.args[1].value = entry->d_name.name;
421 req->out.numargs = 2;
422 if (fc->minor < 9)
423 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
424 else
425 req->out.args[0].size = sizeof(outentry);
426 req->out.args[0].value = &outentry;
427 req->out.args[1].size = sizeof(outopen);
428 req->out.args[1].value = &outopen;
429 fuse_request_send(fc, req);
430 err = req->out.h.error;
431 if (err) {
432 if (err == -ENOSYS)
433 fc->no_create = 1;
434 goto out_free_ff;
435 }
436
437 err = -EIO;
438 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
439 goto out_free_ff;
440
441 fuse_put_request(fc, req);
442 ff->fh = outopen.fh;
443 ff->nodeid = outentry.nodeid;
444 ff->open_flags = outopen.open_flags;
445 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
446 &outentry.attr, entry_attr_timeout(&outentry), 0);
447 if (!inode) {
448 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
449 fuse_sync_release(ff, flags);
450 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
451 return -ENOMEM;
452 }
453 kfree(forget);
454 d_instantiate(entry, inode);
455 fuse_change_entry_timeout(entry, &outentry);
456 fuse_invalidate_attr(dir);
457 file = lookup_instantiate_filp(nd, entry, generic_file_open);
458 if (IS_ERR(file)) {
459 fuse_sync_release(ff, flags);
460 return PTR_ERR(file);
461 }
462 file->private_data = fuse_file_get(ff);
463 fuse_finish_open(inode, file);
464 return 0;
465
466 out_free_ff:
467 fuse_file_free(ff);
468 out_put_request:
469 fuse_put_request(fc, req);
470 out_put_forget_req:
471 kfree(forget);
472 return err;
473}
474
475/*
476 * Code shared between mknod, mkdir, symlink and link
477 */
478static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
479 struct inode *dir, struct dentry *entry,
480 umode_t mode)
481{
482 struct fuse_entry_out outarg;
483 struct inode *inode;
484 int err;
485 struct fuse_forget_link *forget;
486
487 forget = fuse_alloc_forget();
488 if (!forget) {
489 fuse_put_request(fc, req);
490 return -ENOMEM;
491 }
492
493 memset(&outarg, 0, sizeof(outarg));
494 req->in.h.nodeid = get_node_id(dir);
495 req->out.numargs = 1;
496 if (fc->minor < 9)
497 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
498 else
499 req->out.args[0].size = sizeof(outarg);
500 req->out.args[0].value = &outarg;
501 fuse_request_send(fc, req);
502 err = req->out.h.error;
503 fuse_put_request(fc, req);
504 if (err)
505 goto out_put_forget_req;
506
507 err = -EIO;
508 if (invalid_nodeid(outarg.nodeid))
509 goto out_put_forget_req;
510
511 if ((outarg.attr.mode ^ mode) & S_IFMT)
512 goto out_put_forget_req;
513
514 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
515 &outarg.attr, entry_attr_timeout(&outarg), 0);
516 if (!inode) {
517 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
518 return -ENOMEM;
519 }
520 kfree(forget);
521
522 if (S_ISDIR(inode->i_mode)) {
523 struct dentry *alias;
524 mutex_lock(&fc->inst_mutex);
525 alias = d_find_alias(inode);
526 if (alias) {
527 /* New directory must have moved since mkdir */
528 mutex_unlock(&fc->inst_mutex);
529 dput(alias);
530 iput(inode);
531 return -EBUSY;
532 }
533 d_instantiate(entry, inode);
534 mutex_unlock(&fc->inst_mutex);
535 } else
536 d_instantiate(entry, inode);
537
538 fuse_change_entry_timeout(entry, &outarg);
539 fuse_invalidate_attr(dir);
540 return 0;
541
542 out_put_forget_req:
543 kfree(forget);
544 return err;
545}
546
547static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
548 dev_t rdev)
549{
550 struct fuse_mknod_in inarg;
551 struct fuse_conn *fc = get_fuse_conn(dir);
552 struct fuse_req *req = fuse_get_req(fc);
553 if (IS_ERR(req))
554 return PTR_ERR(req);
555
556 if (!fc->dont_mask)
557 mode &= ~current_umask();
558
559 memset(&inarg, 0, sizeof(inarg));
560 inarg.mode = mode;
561 inarg.rdev = new_encode_dev(rdev);
562 inarg.umask = current_umask();
563 req->in.h.opcode = FUSE_MKNOD;
564 req->in.numargs = 2;
565 req->in.args[0].size = fc->minor < 12 ? FUSE_COMPAT_MKNOD_IN_SIZE :
566 sizeof(inarg);
567 req->in.args[0].value = &inarg;
568 req->in.args[1].size = entry->d_name.len + 1;
569 req->in.args[1].value = entry->d_name.name;
570 return create_new_entry(fc, req, dir, entry, mode);
571}
572
573static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
574 struct nameidata *nd)
575{
576 if (nd) {
577 int err = fuse_create_open(dir, entry, mode, nd);
578 if (err != -ENOSYS)
579 return err;
580 /* Fall back on mknod */
581 }
582 return fuse_mknod(dir, entry, mode, 0);
583}
584
585static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
586{
587 struct fuse_mkdir_in inarg;
588 struct fuse_conn *fc = get_fuse_conn(dir);
589 struct fuse_req *req = fuse_get_req(fc);
590 if (IS_ERR(req))
591 return PTR_ERR(req);
592
593 if (!fc->dont_mask)
594 mode &= ~current_umask();
595
596 memset(&inarg, 0, sizeof(inarg));
597 inarg.mode = mode;
598 inarg.umask = current_umask();
599 req->in.h.opcode = FUSE_MKDIR;
600 req->in.numargs = 2;
601 req->in.args[0].size = sizeof(inarg);
602 req->in.args[0].value = &inarg;
603 req->in.args[1].size = entry->d_name.len + 1;
604 req->in.args[1].value = entry->d_name.name;
605 return create_new_entry(fc, req, dir, entry, S_IFDIR);
606}
607
608static int fuse_symlink(struct inode *dir, struct dentry *entry,
609 const char *link)
610{
611 struct fuse_conn *fc = get_fuse_conn(dir);
612 unsigned len = strlen(link) + 1;
613 struct fuse_req *req = fuse_get_req(fc);
614 if (IS_ERR(req))
615 return PTR_ERR(req);
616
617 req->in.h.opcode = FUSE_SYMLINK;
618 req->in.numargs = 2;
619 req->in.args[0].size = entry->d_name.len + 1;
620 req->in.args[0].value = entry->d_name.name;
621 req->in.args[1].size = len;
622 req->in.args[1].value = link;
623 return create_new_entry(fc, req, dir, entry, S_IFLNK);
624}
625
626static int fuse_unlink(struct inode *dir, struct dentry *entry)
627{
628 int err;
629 struct fuse_conn *fc = get_fuse_conn(dir);
630 struct fuse_req *req = fuse_get_req(fc);
631 if (IS_ERR(req))
632 return PTR_ERR(req);
633
634 req->in.h.opcode = FUSE_UNLINK;
635 req->in.h.nodeid = get_node_id(dir);
636 req->in.numargs = 1;
637 req->in.args[0].size = entry->d_name.len + 1;
638 req->in.args[0].value = entry->d_name.name;
639 fuse_request_send(fc, req);
640 err = req->out.h.error;
641 fuse_put_request(fc, req);
642 if (!err) {
643 struct inode *inode = entry->d_inode;
644 struct fuse_inode *fi = get_fuse_inode(inode);
645
646 spin_lock(&fc->lock);
647 fi->attr_version = ++fc->attr_version;
648 drop_nlink(inode);
649 spin_unlock(&fc->lock);
650 fuse_invalidate_attr(inode);
651 fuse_invalidate_attr(dir);
652 fuse_invalidate_entry_cache(entry);
653 } else if (err == -EINTR)
654 fuse_invalidate_entry(entry);
655 return err;
656}
657
658static int fuse_rmdir(struct inode *dir, struct dentry *entry)
659{
660 int err;
661 struct fuse_conn *fc = get_fuse_conn(dir);
662 struct fuse_req *req = fuse_get_req(fc);
663 if (IS_ERR(req))
664 return PTR_ERR(req);
665
666 req->in.h.opcode = FUSE_RMDIR;
667 req->in.h.nodeid = get_node_id(dir);
668 req->in.numargs = 1;
669 req->in.args[0].size = entry->d_name.len + 1;
670 req->in.args[0].value = entry->d_name.name;
671 fuse_request_send(fc, req);
672 err = req->out.h.error;
673 fuse_put_request(fc, req);
674 if (!err) {
675 clear_nlink(entry->d_inode);
676 fuse_invalidate_attr(dir);
677 fuse_invalidate_entry_cache(entry);
678 } else if (err == -EINTR)
679 fuse_invalidate_entry(entry);
680 return err;
681}
682
683static int fuse_rename(struct inode *olddir, struct dentry *oldent,
684 struct inode *newdir, struct dentry *newent)
685{
686 int err;
687 struct fuse_rename_in inarg;
688 struct fuse_conn *fc = get_fuse_conn(olddir);
689 struct fuse_req *req = fuse_get_req(fc);
690
691 if (IS_ERR(req))
692 return PTR_ERR(req);
693
694 memset(&inarg, 0, sizeof(inarg));
695 inarg.newdir = get_node_id(newdir);
696 req->in.h.opcode = FUSE_RENAME;
697 req->in.h.nodeid = get_node_id(olddir);
698 req->in.numargs = 3;
699 req->in.args[0].size = sizeof(inarg);
700 req->in.args[0].value = &inarg;
701 req->in.args[1].size = oldent->d_name.len + 1;
702 req->in.args[1].value = oldent->d_name.name;
703 req->in.args[2].size = newent->d_name.len + 1;
704 req->in.args[2].value = newent->d_name.name;
705 fuse_request_send(fc, req);
706 err = req->out.h.error;
707 fuse_put_request(fc, req);
708 if (!err) {
709 /* ctime changes */
710 fuse_invalidate_attr(oldent->d_inode);
711
712 fuse_invalidate_attr(olddir);
713 if (olddir != newdir)
714 fuse_invalidate_attr(newdir);
715
716 /* newent will end up negative */
717 if (newent->d_inode) {
718 fuse_invalidate_attr(newent->d_inode);
719 fuse_invalidate_entry_cache(newent);
720 }
721 } else if (err == -EINTR) {
722 /* If request was interrupted, DEITY only knows if the
723 rename actually took place. If the invalidation
724 fails (e.g. some process has CWD under the renamed
725 directory), then there can be inconsistency between
726 the dcache and the real filesystem. Tough luck. */
727 fuse_invalidate_entry(oldent);
728 if (newent->d_inode)
729 fuse_invalidate_entry(newent);
730 }
731
732 return err;
733}
734
735static int fuse_link(struct dentry *entry, struct inode *newdir,
736 struct dentry *newent)
737{
738 int err;
739 struct fuse_link_in inarg;
740 struct inode *inode = entry->d_inode;
741 struct fuse_conn *fc = get_fuse_conn(inode);
742 struct fuse_req *req = fuse_get_req(fc);
743 if (IS_ERR(req))
744 return PTR_ERR(req);
745
746 memset(&inarg, 0, sizeof(inarg));
747 inarg.oldnodeid = get_node_id(inode);
748 req->in.h.opcode = FUSE_LINK;
749 req->in.numargs = 2;
750 req->in.args[0].size = sizeof(inarg);
751 req->in.args[0].value = &inarg;
752 req->in.args[1].size = newent->d_name.len + 1;
753 req->in.args[1].value = newent->d_name.name;
754 err = create_new_entry(fc, req, newdir, newent, inode->i_mode);
755 /* Contrary to "normal" filesystems it can happen that link
756 makes two "logical" inodes point to the same "physical"
757 inode. We invalidate the attributes of the old one, so it
758 will reflect changes in the backing inode (link count,
759 etc.)
760 */
761 if (!err) {
762 struct fuse_inode *fi = get_fuse_inode(inode);
763
764 spin_lock(&fc->lock);
765 fi->attr_version = ++fc->attr_version;
766 inc_nlink(inode);
767 spin_unlock(&fc->lock);
768 fuse_invalidate_attr(inode);
769 } else if (err == -EINTR) {
770 fuse_invalidate_attr(inode);
771 }
772 return err;
773}
774
775static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
776 struct kstat *stat)
777{
778 unsigned int blkbits;
779
780 stat->dev = inode->i_sb->s_dev;
781 stat->ino = attr->ino;
782 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
783 stat->nlink = attr->nlink;
784 stat->uid = attr->uid;
785 stat->gid = attr->gid;
786 stat->rdev = inode->i_rdev;
787 stat->atime.tv_sec = attr->atime;
788 stat->atime.tv_nsec = attr->atimensec;
789 stat->mtime.tv_sec = attr->mtime;
790 stat->mtime.tv_nsec = attr->mtimensec;
791 stat->ctime.tv_sec = attr->ctime;
792 stat->ctime.tv_nsec = attr->ctimensec;
793 stat->size = attr->size;
794 stat->blocks = attr->blocks;
795
796 if (attr->blksize != 0)
797 blkbits = ilog2(attr->blksize);
798 else
799 blkbits = inode->i_sb->s_blocksize_bits;
800
801 stat->blksize = 1 << blkbits;
802}
803
804static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
805 struct file *file)
806{
807 int err;
808 struct fuse_getattr_in inarg;
809 struct fuse_attr_out outarg;
810 struct fuse_conn *fc = get_fuse_conn(inode);
811 struct fuse_req *req;
812 u64 attr_version;
813
814 req = fuse_get_req(fc);
815 if (IS_ERR(req))
816 return PTR_ERR(req);
817
818 attr_version = fuse_get_attr_version(fc);
819
820 memset(&inarg, 0, sizeof(inarg));
821 memset(&outarg, 0, sizeof(outarg));
822 /* Directories have separate file-handle space */
823 if (file && S_ISREG(inode->i_mode)) {
824 struct fuse_file *ff = file->private_data;
825
826 inarg.getattr_flags |= FUSE_GETATTR_FH;
827 inarg.fh = ff->fh;
828 }
829 req->in.h.opcode = FUSE_GETATTR;
830 req->in.h.nodeid = get_node_id(inode);
831 req->in.numargs = 1;
832 req->in.args[0].size = sizeof(inarg);
833 req->in.args[0].value = &inarg;
834 req->out.numargs = 1;
835 if (fc->minor < 9)
836 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
837 else
838 req->out.args[0].size = sizeof(outarg);
839 req->out.args[0].value = &outarg;
840 fuse_request_send(fc, req);
841 err = req->out.h.error;
842 fuse_put_request(fc, req);
843 if (!err) {
844 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
845 make_bad_inode(inode);
846 err = -EIO;
847 } else {
848 fuse_change_attributes(inode, &outarg.attr,
849 attr_timeout(&outarg),
850 attr_version);
851 if (stat)
852 fuse_fillattr(inode, &outarg.attr, stat);
853 }
854 }
855 return err;
856}
857
858int fuse_update_attributes(struct inode *inode, struct kstat *stat,
859 struct file *file, bool *refreshed)
860{
861 struct fuse_inode *fi = get_fuse_inode(inode);
862 int err;
863 bool r;
864
865 if (fi->i_time < get_jiffies_64()) {
866 r = true;
867 err = fuse_do_getattr(inode, stat, file);
868 } else {
869 r = false;
870 err = 0;
871 if (stat) {
872 generic_fillattr(inode, stat);
873 stat->mode = fi->orig_i_mode;
874 stat->ino = fi->orig_ino;
875 }
876 }
877
878 if (refreshed != NULL)
879 *refreshed = r;
880
881 return err;
882}
883
884int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
885 u64 child_nodeid, struct qstr *name)
886{
887 int err = -ENOTDIR;
888 struct inode *parent;
889 struct dentry *dir;
890 struct dentry *entry;
891
892 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
893 if (!parent)
894 return -ENOENT;
895
896 mutex_lock(&parent->i_mutex);
897 if (!S_ISDIR(parent->i_mode))
898 goto unlock;
899
900 err = -ENOENT;
901 dir = d_find_alias(parent);
902 if (!dir)
903 goto unlock;
904
905 entry = d_lookup(dir, name);
906 dput(dir);
907 if (!entry)
908 goto unlock;
909
910 fuse_invalidate_attr(parent);
911 fuse_invalidate_entry(entry);
912
913 if (child_nodeid != 0 && entry->d_inode) {
914 mutex_lock(&entry->d_inode->i_mutex);
915 if (get_node_id(entry->d_inode) != child_nodeid) {
916 err = -ENOENT;
917 goto badentry;
918 }
919 if (d_mountpoint(entry)) {
920 err = -EBUSY;
921 goto badentry;
922 }
923 if (S_ISDIR(entry->d_inode->i_mode)) {
924 shrink_dcache_parent(entry);
925 if (!simple_empty(entry)) {
926 err = -ENOTEMPTY;
927 goto badentry;
928 }
929 entry->d_inode->i_flags |= S_DEAD;
930 }
931 dont_mount(entry);
932 clear_nlink(entry->d_inode);
933 err = 0;
934 badentry:
935 mutex_unlock(&entry->d_inode->i_mutex);
936 if (!err)
937 d_delete(entry);
938 } else {
939 err = 0;
940 }
941 dput(entry);
942
943 unlock:
944 mutex_unlock(&parent->i_mutex);
945 iput(parent);
946 return err;
947}
948
949/*
950 * Calling into a user-controlled filesystem gives the filesystem
951 * daemon ptrace-like capabilities over the requester process. This
952 * means, that the filesystem daemon is able to record the exact
953 * filesystem operations performed, and can also control the behavior
954 * of the requester process in otherwise impossible ways. For example
955 * it can delay the operation for arbitrary length of time allowing
956 * DoS against the requester.
957 *
958 * For this reason only those processes can call into the filesystem,
959 * for which the owner of the mount has ptrace privilege. This
960 * excludes processes started by other users, suid or sgid processes.
961 */
962int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task)
963{
964 const struct cred *cred;
965 int ret;
966
967 if (fc->flags & FUSE_ALLOW_OTHER)
968 return 1;
969
970 rcu_read_lock();
971 ret = 0;
972 cred = __task_cred(task);
973 if (cred->euid == fc->user_id &&
974 cred->suid == fc->user_id &&
975 cred->uid == fc->user_id &&
976 cred->egid == fc->group_id &&
977 cred->sgid == fc->group_id &&
978 cred->gid == fc->group_id)
979 ret = 1;
980 rcu_read_unlock();
981
982 return ret;
983}
984
985static int fuse_access(struct inode *inode, int mask)
986{
987 struct fuse_conn *fc = get_fuse_conn(inode);
988 struct fuse_req *req;
989 struct fuse_access_in inarg;
990 int err;
991
992 if (fc->no_access)
993 return 0;
994
995 req = fuse_get_req(fc);
996 if (IS_ERR(req))
997 return PTR_ERR(req);
998
999 memset(&inarg, 0, sizeof(inarg));
1000 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1001 req->in.h.opcode = FUSE_ACCESS;
1002 req->in.h.nodeid = get_node_id(inode);
1003 req->in.numargs = 1;
1004 req->in.args[0].size = sizeof(inarg);
1005 req->in.args[0].value = &inarg;
1006 fuse_request_send(fc, req);
1007 err = req->out.h.error;
1008 fuse_put_request(fc, req);
1009 if (err == -ENOSYS) {
1010 fc->no_access = 1;
1011 err = 0;
1012 }
1013 return err;
1014}
1015
1016static int fuse_perm_getattr(struct inode *inode, int mask)
1017{
1018 if (mask & MAY_NOT_BLOCK)
1019 return -ECHILD;
1020
1021 return fuse_do_getattr(inode, NULL, NULL);
1022}
1023
1024/*
1025 * Check permission. The two basic access models of FUSE are:
1026 *
1027 * 1) Local access checking ('default_permissions' mount option) based
1028 * on file mode. This is the plain old disk filesystem permission
1029 * modell.
1030 *
1031 * 2) "Remote" access checking, where server is responsible for
1032 * checking permission in each inode operation. An exception to this
1033 * is if ->permission() was invoked from sys_access() in which case an
1034 * access request is sent. Execute permission is still checked
1035 * locally based on file mode.
1036 */
1037static int fuse_permission(struct inode *inode, int mask)
1038{
1039 struct fuse_conn *fc = get_fuse_conn(inode);
1040 bool refreshed = false;
1041 int err = 0;
1042
1043 if (!fuse_allow_task(fc, current))
1044 return -EACCES;
1045
1046 /*
1047 * If attributes are needed, refresh them before proceeding
1048 */
1049 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1050 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1051 struct fuse_inode *fi = get_fuse_inode(inode);
1052
1053 if (fi->i_time < get_jiffies_64()) {
1054 refreshed = true;
1055
1056 err = fuse_perm_getattr(inode, mask);
1057 if (err)
1058 return err;
1059 }
1060 }
1061
1062 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1063 err = generic_permission(inode, mask);
1064
1065 /* If permission is denied, try to refresh file
1066 attributes. This is also needed, because the root
1067 node will at first have no permissions */
1068 if (err == -EACCES && !refreshed) {
1069 err = fuse_perm_getattr(inode, mask);
1070 if (!err)
1071 err = generic_permission(inode, mask);
1072 }
1073
1074 /* Note: the opposite of the above test does not
1075 exist. So if permissions are revoked this won't be
1076 noticed immediately, only after the attribute
1077 timeout has expired */
1078 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1079 if (mask & MAY_NOT_BLOCK)
1080 return -ECHILD;
1081
1082 err = fuse_access(inode, mask);
1083 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1084 if (!(inode->i_mode & S_IXUGO)) {
1085 if (refreshed)
1086 return -EACCES;
1087
1088 err = fuse_perm_getattr(inode, mask);
1089 if (!err && !(inode->i_mode & S_IXUGO))
1090 return -EACCES;
1091 }
1092 }
1093 return err;
1094}
1095
1096static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1097 void *dstbuf, filldir_t filldir)
1098{
1099 while (nbytes >= FUSE_NAME_OFFSET) {
1100 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1101 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1102 int over;
1103 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1104 return -EIO;
1105 if (reclen > nbytes)
1106 break;
1107
1108 over = filldir(dstbuf, dirent->name, dirent->namelen,
1109 file->f_pos, dirent->ino, dirent->type);
1110 if (over)
1111 break;
1112
1113 buf += reclen;
1114 nbytes -= reclen;
1115 file->f_pos = dirent->off;
1116 }
1117
1118 return 0;
1119}
1120
1121static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
1122{
1123 int err;
1124 size_t nbytes;
1125 struct page *page;
1126 struct inode *inode = file->f_path.dentry->d_inode;
1127 struct fuse_conn *fc = get_fuse_conn(inode);
1128 struct fuse_req *req;
1129
1130 if (is_bad_inode(inode))
1131 return -EIO;
1132
1133 req = fuse_get_req(fc);
1134 if (IS_ERR(req))
1135 return PTR_ERR(req);
1136
1137 page = alloc_page(GFP_KERNEL);
1138 if (!page) {
1139 fuse_put_request(fc, req);
1140 return -ENOMEM;
1141 }
1142 req->out.argpages = 1;
1143 req->num_pages = 1;
1144 req->pages[0] = page;
1145 fuse_read_fill(req, file, file->f_pos, PAGE_SIZE, FUSE_READDIR);
1146 fuse_request_send(fc, req);
1147 nbytes = req->out.args[0].size;
1148 err = req->out.h.error;
1149 fuse_put_request(fc, req);
1150 if (!err)
1151 err = parse_dirfile(page_address(page), nbytes, file, dstbuf,
1152 filldir);
1153
1154 __free_page(page);
1155 fuse_invalidate_attr(inode); /* atime changed */
1156 return err;
1157}
1158
1159static char *read_link(struct dentry *dentry)
1160{
1161 struct inode *inode = dentry->d_inode;
1162 struct fuse_conn *fc = get_fuse_conn(inode);
1163 struct fuse_req *req = fuse_get_req(fc);
1164 char *link;
1165
1166 if (IS_ERR(req))
1167 return ERR_CAST(req);
1168
1169 link = (char *) __get_free_page(GFP_KERNEL);
1170 if (!link) {
1171 link = ERR_PTR(-ENOMEM);
1172 goto out;
1173 }
1174 req->in.h.opcode = FUSE_READLINK;
1175 req->in.h.nodeid = get_node_id(inode);
1176 req->out.argvar = 1;
1177 req->out.numargs = 1;
1178 req->out.args[0].size = PAGE_SIZE - 1;
1179 req->out.args[0].value = link;
1180 fuse_request_send(fc, req);
1181 if (req->out.h.error) {
1182 free_page((unsigned long) link);
1183 link = ERR_PTR(req->out.h.error);
1184 } else
1185 link[req->out.args[0].size] = '\0';
1186 out:
1187 fuse_put_request(fc, req);
1188 fuse_invalidate_attr(inode); /* atime changed */
1189 return link;
1190}
1191
1192static void free_link(char *link)
1193{
1194 if (!IS_ERR(link))
1195 free_page((unsigned long) link);
1196}
1197
1198static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
1199{
1200 nd_set_link(nd, read_link(dentry));
1201 return NULL;
1202}
1203
1204static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
1205{
1206 free_link(nd_get_link(nd));
1207}
1208
1209static int fuse_dir_open(struct inode *inode, struct file *file)
1210{
1211 return fuse_open_common(inode, file, true);
1212}
1213
1214static int fuse_dir_release(struct inode *inode, struct file *file)
1215{
1216 fuse_release_common(file, FUSE_RELEASEDIR);
1217
1218 return 0;
1219}
1220
1221static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1222 int datasync)
1223{
1224 return fuse_fsync_common(file, start, end, datasync, 1);
1225}
1226
1227static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1228 unsigned long arg)
1229{
1230 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1231
1232 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1233 if (fc->minor < 18)
1234 return -ENOTTY;
1235
1236 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1237}
1238
1239static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1240 unsigned long arg)
1241{
1242 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1243
1244 if (fc->minor < 18)
1245 return -ENOTTY;
1246
1247 return fuse_ioctl_common(file, cmd, arg,
1248 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1249}
1250
1251static bool update_mtime(unsigned ivalid)
1252{
1253 /* Always update if mtime is explicitly set */
1254 if (ivalid & ATTR_MTIME_SET)
1255 return true;
1256
1257 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1258 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1259 return false;
1260
1261 /* In all other cases update */
1262 return true;
1263}
1264
1265static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
1266{
1267 unsigned ivalid = iattr->ia_valid;
1268
1269 if (ivalid & ATTR_MODE)
1270 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1271 if (ivalid & ATTR_UID)
1272 arg->valid |= FATTR_UID, arg->uid = iattr->ia_uid;
1273 if (ivalid & ATTR_GID)
1274 arg->valid |= FATTR_GID, arg->gid = iattr->ia_gid;
1275 if (ivalid & ATTR_SIZE)
1276 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1277 if (ivalid & ATTR_ATIME) {
1278 arg->valid |= FATTR_ATIME;
1279 arg->atime = iattr->ia_atime.tv_sec;
1280 arg->atimensec = iattr->ia_atime.tv_nsec;
1281 if (!(ivalid & ATTR_ATIME_SET))
1282 arg->valid |= FATTR_ATIME_NOW;
1283 }
1284 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid)) {
1285 arg->valid |= FATTR_MTIME;
1286 arg->mtime = iattr->ia_mtime.tv_sec;
1287 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1288 if (!(ivalid & ATTR_MTIME_SET))
1289 arg->valid |= FATTR_MTIME_NOW;
1290 }
1291}
1292
1293/*
1294 * Prevent concurrent writepages on inode
1295 *
1296 * This is done by adding a negative bias to the inode write counter
1297 * and waiting for all pending writes to finish.
1298 */
1299void fuse_set_nowrite(struct inode *inode)
1300{
1301 struct fuse_conn *fc = get_fuse_conn(inode);
1302 struct fuse_inode *fi = get_fuse_inode(inode);
1303
1304 BUG_ON(!mutex_is_locked(&inode->i_mutex));
1305
1306 spin_lock(&fc->lock);
1307 BUG_ON(fi->writectr < 0);
1308 fi->writectr += FUSE_NOWRITE;
1309 spin_unlock(&fc->lock);
1310 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1311}
1312
1313/*
1314 * Allow writepages on inode
1315 *
1316 * Remove the bias from the writecounter and send any queued
1317 * writepages.
1318 */
1319static void __fuse_release_nowrite(struct inode *inode)
1320{
1321 struct fuse_inode *fi = get_fuse_inode(inode);
1322
1323 BUG_ON(fi->writectr != FUSE_NOWRITE);
1324 fi->writectr = 0;
1325 fuse_flush_writepages(inode);
1326}
1327
1328void fuse_release_nowrite(struct inode *inode)
1329{
1330 struct fuse_conn *fc = get_fuse_conn(inode);
1331
1332 spin_lock(&fc->lock);
1333 __fuse_release_nowrite(inode);
1334 spin_unlock(&fc->lock);
1335}
1336
1337/*
1338 * Set attributes, and at the same time refresh them.
1339 *
1340 * Truncation is slightly complicated, because the 'truncate' request
1341 * may fail, in which case we don't want to touch the mapping.
1342 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1343 * and the actual truncation by hand.
1344 */
1345static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
1346 struct file *file)
1347{
1348 struct inode *inode = entry->d_inode;
1349 struct fuse_conn *fc = get_fuse_conn(inode);
1350 struct fuse_req *req;
1351 struct fuse_setattr_in inarg;
1352 struct fuse_attr_out outarg;
1353 bool is_truncate = false;
1354 loff_t oldsize;
1355 int err;
1356
1357 if (!fuse_allow_task(fc, current))
1358 return -EACCES;
1359
1360 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1361 attr->ia_valid |= ATTR_FORCE;
1362
1363 err = inode_change_ok(inode, attr);
1364 if (err)
1365 return err;
1366
1367 if (attr->ia_valid & ATTR_OPEN) {
1368 if (fc->atomic_o_trunc)
1369 return 0;
1370 file = NULL;
1371 }
1372
1373 if (attr->ia_valid & ATTR_SIZE)
1374 is_truncate = true;
1375
1376 req = fuse_get_req(fc);
1377 if (IS_ERR(req))
1378 return PTR_ERR(req);
1379
1380 if (is_truncate)
1381 fuse_set_nowrite(inode);
1382
1383 memset(&inarg, 0, sizeof(inarg));
1384 memset(&outarg, 0, sizeof(outarg));
1385 iattr_to_fattr(attr, &inarg);
1386 if (file) {
1387 struct fuse_file *ff = file->private_data;
1388 inarg.valid |= FATTR_FH;
1389 inarg.fh = ff->fh;
1390 }
1391 if (attr->ia_valid & ATTR_SIZE) {
1392 /* For mandatory locking in truncate */
1393 inarg.valid |= FATTR_LOCKOWNER;
1394 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1395 }
1396 req->in.h.opcode = FUSE_SETATTR;
1397 req->in.h.nodeid = get_node_id(inode);
1398 req->in.numargs = 1;
1399 req->in.args[0].size = sizeof(inarg);
1400 req->in.args[0].value = &inarg;
1401 req->out.numargs = 1;
1402 if (fc->minor < 9)
1403 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
1404 else
1405 req->out.args[0].size = sizeof(outarg);
1406 req->out.args[0].value = &outarg;
1407 fuse_request_send(fc, req);
1408 err = req->out.h.error;
1409 fuse_put_request(fc, req);
1410 if (err) {
1411 if (err == -EINTR)
1412 fuse_invalidate_attr(inode);
1413 goto error;
1414 }
1415
1416 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1417 make_bad_inode(inode);
1418 err = -EIO;
1419 goto error;
1420 }
1421
1422 spin_lock(&fc->lock);
1423 fuse_change_attributes_common(inode, &outarg.attr,
1424 attr_timeout(&outarg));
1425 oldsize = inode->i_size;
1426 i_size_write(inode, outarg.attr.size);
1427
1428 if (is_truncate) {
1429 /* NOTE: this may release/reacquire fc->lock */
1430 __fuse_release_nowrite(inode);
1431 }
1432 spin_unlock(&fc->lock);
1433
1434 /*
1435 * Only call invalidate_inode_pages2() after removing
1436 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1437 */
1438 if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1439 truncate_pagecache(inode, oldsize, outarg.attr.size);
1440 invalidate_inode_pages2(inode->i_mapping);
1441 }
1442
1443 return 0;
1444
1445error:
1446 if (is_truncate)
1447 fuse_release_nowrite(inode);
1448
1449 return err;
1450}
1451
1452static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1453{
1454 if (attr->ia_valid & ATTR_FILE)
1455 return fuse_do_setattr(entry, attr, attr->ia_file);
1456 else
1457 return fuse_do_setattr(entry, attr, NULL);
1458}
1459
1460static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1461 struct kstat *stat)
1462{
1463 struct inode *inode = entry->d_inode;
1464 struct fuse_conn *fc = get_fuse_conn(inode);
1465
1466 if (!fuse_allow_task(fc, current))
1467 return -EACCES;
1468
1469 return fuse_update_attributes(inode, stat, NULL, NULL);
1470}
1471
1472static int fuse_setxattr(struct dentry *entry, const char *name,
1473 const void *value, size_t size, int flags)
1474{
1475 struct inode *inode = entry->d_inode;
1476 struct fuse_conn *fc = get_fuse_conn(inode);
1477 struct fuse_req *req;
1478 struct fuse_setxattr_in inarg;
1479 int err;
1480
1481 if (fc->no_setxattr)
1482 return -EOPNOTSUPP;
1483
1484 req = fuse_get_req(fc);
1485 if (IS_ERR(req))
1486 return PTR_ERR(req);
1487
1488 memset(&inarg, 0, sizeof(inarg));
1489 inarg.size = size;
1490 inarg.flags = flags;
1491 req->in.h.opcode = FUSE_SETXATTR;
1492 req->in.h.nodeid = get_node_id(inode);
1493 req->in.numargs = 3;
1494 req->in.args[0].size = sizeof(inarg);
1495 req->in.args[0].value = &inarg;
1496 req->in.args[1].size = strlen(name) + 1;
1497 req->in.args[1].value = name;
1498 req->in.args[2].size = size;
1499 req->in.args[2].value = value;
1500 fuse_request_send(fc, req);
1501 err = req->out.h.error;
1502 fuse_put_request(fc, req);
1503 if (err == -ENOSYS) {
1504 fc->no_setxattr = 1;
1505 err = -EOPNOTSUPP;
1506 }
1507 return err;
1508}
1509
1510static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
1511 void *value, size_t size)
1512{
1513 struct inode *inode = entry->d_inode;
1514 struct fuse_conn *fc = get_fuse_conn(inode);
1515 struct fuse_req *req;
1516 struct fuse_getxattr_in inarg;
1517 struct fuse_getxattr_out outarg;
1518 ssize_t ret;
1519
1520 if (fc->no_getxattr)
1521 return -EOPNOTSUPP;
1522
1523 req = fuse_get_req(fc);
1524 if (IS_ERR(req))
1525 return PTR_ERR(req);
1526
1527 memset(&inarg, 0, sizeof(inarg));
1528 inarg.size = size;
1529 req->in.h.opcode = FUSE_GETXATTR;
1530 req->in.h.nodeid = get_node_id(inode);
1531 req->in.numargs = 2;
1532 req->in.args[0].size = sizeof(inarg);
1533 req->in.args[0].value = &inarg;
1534 req->in.args[1].size = strlen(name) + 1;
1535 req->in.args[1].value = name;
1536 /* This is really two different operations rolled into one */
1537 req->out.numargs = 1;
1538 if (size) {
1539 req->out.argvar = 1;
1540 req->out.args[0].size = size;
1541 req->out.args[0].value = value;
1542 } else {
1543 req->out.args[0].size = sizeof(outarg);
1544 req->out.args[0].value = &outarg;
1545 }
1546 fuse_request_send(fc, req);
1547 ret = req->out.h.error;
1548 if (!ret)
1549 ret = size ? req->out.args[0].size : outarg.size;
1550 else {
1551 if (ret == -ENOSYS) {
1552 fc->no_getxattr = 1;
1553 ret = -EOPNOTSUPP;
1554 }
1555 }
1556 fuse_put_request(fc, req);
1557 return ret;
1558}
1559
1560static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
1561{
1562 struct inode *inode = entry->d_inode;
1563 struct fuse_conn *fc = get_fuse_conn(inode);
1564 struct fuse_req *req;
1565 struct fuse_getxattr_in inarg;
1566 struct fuse_getxattr_out outarg;
1567 ssize_t ret;
1568
1569 if (!fuse_allow_task(fc, current))
1570 return -EACCES;
1571
1572 if (fc->no_listxattr)
1573 return -EOPNOTSUPP;
1574
1575 req = fuse_get_req(fc);
1576 if (IS_ERR(req))
1577 return PTR_ERR(req);
1578
1579 memset(&inarg, 0, sizeof(inarg));
1580 inarg.size = size;
1581 req->in.h.opcode = FUSE_LISTXATTR;
1582 req->in.h.nodeid = get_node_id(inode);
1583 req->in.numargs = 1;
1584 req->in.args[0].size = sizeof(inarg);
1585 req->in.args[0].value = &inarg;
1586 /* This is really two different operations rolled into one */
1587 req->out.numargs = 1;
1588 if (size) {
1589 req->out.argvar = 1;
1590 req->out.args[0].size = size;
1591 req->out.args[0].value = list;
1592 } else {
1593 req->out.args[0].size = sizeof(outarg);
1594 req->out.args[0].value = &outarg;
1595 }
1596 fuse_request_send(fc, req);
1597 ret = req->out.h.error;
1598 if (!ret)
1599 ret = size ? req->out.args[0].size : outarg.size;
1600 else {
1601 if (ret == -ENOSYS) {
1602 fc->no_listxattr = 1;
1603 ret = -EOPNOTSUPP;
1604 }
1605 }
1606 fuse_put_request(fc, req);
1607 return ret;
1608}
1609
1610static int fuse_removexattr(struct dentry *entry, const char *name)
1611{
1612 struct inode *inode = entry->d_inode;
1613 struct fuse_conn *fc = get_fuse_conn(inode);
1614 struct fuse_req *req;
1615 int err;
1616
1617 if (fc->no_removexattr)
1618 return -EOPNOTSUPP;
1619
1620 req = fuse_get_req(fc);
1621 if (IS_ERR(req))
1622 return PTR_ERR(req);
1623
1624 req->in.h.opcode = FUSE_REMOVEXATTR;
1625 req->in.h.nodeid = get_node_id(inode);
1626 req->in.numargs = 1;
1627 req->in.args[0].size = strlen(name) + 1;
1628 req->in.args[0].value = name;
1629 fuse_request_send(fc, req);
1630 err = req->out.h.error;
1631 fuse_put_request(fc, req);
1632 if (err == -ENOSYS) {
1633 fc->no_removexattr = 1;
1634 err = -EOPNOTSUPP;
1635 }
1636 return err;
1637}
1638
1639static const struct inode_operations fuse_dir_inode_operations = {
1640 .lookup = fuse_lookup,
1641 .mkdir = fuse_mkdir,
1642 .symlink = fuse_symlink,
1643 .unlink = fuse_unlink,
1644 .rmdir = fuse_rmdir,
1645 .rename = fuse_rename,
1646 .link = fuse_link,
1647 .setattr = fuse_setattr,
1648 .create = fuse_create,
1649 .mknod = fuse_mknod,
1650 .permission = fuse_permission,
1651 .getattr = fuse_getattr,
1652 .setxattr = fuse_setxattr,
1653 .getxattr = fuse_getxattr,
1654 .listxattr = fuse_listxattr,
1655 .removexattr = fuse_removexattr,
1656};
1657
1658static const struct file_operations fuse_dir_operations = {
1659 .llseek = generic_file_llseek,
1660 .read = generic_read_dir,
1661 .readdir = fuse_readdir,
1662 .open = fuse_dir_open,
1663 .release = fuse_dir_release,
1664 .fsync = fuse_dir_fsync,
1665 .unlocked_ioctl = fuse_dir_ioctl,
1666 .compat_ioctl = fuse_dir_compat_ioctl,
1667};
1668
1669static const struct inode_operations fuse_common_inode_operations = {
1670 .setattr = fuse_setattr,
1671 .permission = fuse_permission,
1672 .getattr = fuse_getattr,
1673 .setxattr = fuse_setxattr,
1674 .getxattr = fuse_getxattr,
1675 .listxattr = fuse_listxattr,
1676 .removexattr = fuse_removexattr,
1677};
1678
1679static const struct inode_operations fuse_symlink_inode_operations = {
1680 .setattr = fuse_setattr,
1681 .follow_link = fuse_follow_link,
1682 .put_link = fuse_put_link,
1683 .readlink = generic_readlink,
1684 .getattr = fuse_getattr,
1685 .setxattr = fuse_setxattr,
1686 .getxattr = fuse_getxattr,
1687 .listxattr = fuse_listxattr,
1688 .removexattr = fuse_removexattr,
1689};
1690
1691void fuse_init_common(struct inode *inode)
1692{
1693 inode->i_op = &fuse_common_inode_operations;
1694}
1695
1696void fuse_init_dir(struct inode *inode)
1697{
1698 inode->i_op = &fuse_dir_inode_operations;
1699 inode->i_fop = &fuse_dir_operations;
1700}
1701
1702void fuse_init_symlink(struct inode *inode)
1703{
1704 inode->i_op = &fuse_symlink_inode_operations;
1705}
1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7*/
8
9#include "fuse_i.h"
10
11#include <linux/pagemap.h>
12#include <linux/file.h>
13#include <linux/fs_context.h>
14#include <linux/moduleparam.h>
15#include <linux/sched.h>
16#include <linux/namei.h>
17#include <linux/slab.h>
18#include <linux/xattr.h>
19#include <linux/iversion.h>
20#include <linux/posix_acl.h>
21#include <linux/security.h>
22#include <linux/types.h>
23#include <linux/kernel.h>
24
25static bool __read_mostly allow_sys_admin_access;
26module_param(allow_sys_admin_access, bool, 0644);
27MODULE_PARM_DESC(allow_sys_admin_access,
28 "Allow users with CAP_SYS_ADMIN in initial userns to bypass allow_other access check");
29
30static void fuse_advise_use_readdirplus(struct inode *dir)
31{
32 struct fuse_inode *fi = get_fuse_inode(dir);
33
34 set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
35}
36
37#if BITS_PER_LONG >= 64
38static inline void __fuse_dentry_settime(struct dentry *entry, u64 time)
39{
40 entry->d_fsdata = (void *) time;
41}
42
43static inline u64 fuse_dentry_time(const struct dentry *entry)
44{
45 return (u64)entry->d_fsdata;
46}
47
48#else
49union fuse_dentry {
50 u64 time;
51 struct rcu_head rcu;
52};
53
54static inline void __fuse_dentry_settime(struct dentry *dentry, u64 time)
55{
56 ((union fuse_dentry *) dentry->d_fsdata)->time = time;
57}
58
59static inline u64 fuse_dentry_time(const struct dentry *entry)
60{
61 return ((union fuse_dentry *) entry->d_fsdata)->time;
62}
63#endif
64
65static void fuse_dentry_settime(struct dentry *dentry, u64 time)
66{
67 struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
68 bool delete = !time && fc->delete_stale;
69 /*
70 * Mess with DCACHE_OP_DELETE because dput() will be faster without it.
71 * Don't care about races, either way it's just an optimization
72 */
73 if ((!delete && (dentry->d_flags & DCACHE_OP_DELETE)) ||
74 (delete && !(dentry->d_flags & DCACHE_OP_DELETE))) {
75 spin_lock(&dentry->d_lock);
76 if (!delete)
77 dentry->d_flags &= ~DCACHE_OP_DELETE;
78 else
79 dentry->d_flags |= DCACHE_OP_DELETE;
80 spin_unlock(&dentry->d_lock);
81 }
82
83 __fuse_dentry_settime(dentry, time);
84}
85
86/*
87 * FUSE caches dentries and attributes with separate timeout. The
88 * time in jiffies until the dentry/attributes are valid is stored in
89 * dentry->d_fsdata and fuse_inode->i_time respectively.
90 */
91
92/*
93 * Calculate the time in jiffies until a dentry/attributes are valid
94 */
95u64 fuse_time_to_jiffies(u64 sec, u32 nsec)
96{
97 if (sec || nsec) {
98 struct timespec64 ts = {
99 sec,
100 min_t(u32, nsec, NSEC_PER_SEC - 1)
101 };
102
103 return get_jiffies_64() + timespec64_to_jiffies(&ts);
104 } else
105 return 0;
106}
107
108/*
109 * Set dentry and possibly attribute timeouts from the lookup/mk*
110 * replies
111 */
112void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o)
113{
114 fuse_dentry_settime(entry,
115 fuse_time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
116}
117
118void fuse_invalidate_attr_mask(struct inode *inode, u32 mask)
119{
120 set_mask_bits(&get_fuse_inode(inode)->inval_mask, 0, mask);
121}
122
123/*
124 * Mark the attributes as stale, so that at the next call to
125 * ->getattr() they will be fetched from userspace
126 */
127void fuse_invalidate_attr(struct inode *inode)
128{
129 fuse_invalidate_attr_mask(inode, STATX_BASIC_STATS);
130}
131
132static void fuse_dir_changed(struct inode *dir)
133{
134 fuse_invalidate_attr(dir);
135 inode_maybe_inc_iversion(dir, false);
136}
137
138/*
139 * Mark the attributes as stale due to an atime change. Avoid the invalidate if
140 * atime is not used.
141 */
142void fuse_invalidate_atime(struct inode *inode)
143{
144 if (!IS_RDONLY(inode))
145 fuse_invalidate_attr_mask(inode, STATX_ATIME);
146}
147
148/*
149 * Just mark the entry as stale, so that a next attempt to look it up
150 * will result in a new lookup call to userspace
151 *
152 * This is called when a dentry is about to become negative and the
153 * timeout is unknown (unlink, rmdir, rename and in some cases
154 * lookup)
155 */
156void fuse_invalidate_entry_cache(struct dentry *entry)
157{
158 fuse_dentry_settime(entry, 0);
159}
160
161/*
162 * Same as fuse_invalidate_entry_cache(), but also try to remove the
163 * dentry from the hash
164 */
165static void fuse_invalidate_entry(struct dentry *entry)
166{
167 d_invalidate(entry);
168 fuse_invalidate_entry_cache(entry);
169}
170
171static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
172 u64 nodeid, const struct qstr *name,
173 struct fuse_entry_out *outarg)
174{
175 memset(outarg, 0, sizeof(struct fuse_entry_out));
176 args->opcode = FUSE_LOOKUP;
177 args->nodeid = nodeid;
178 args->in_numargs = 1;
179 args->in_args[0].size = name->len + 1;
180 args->in_args[0].value = name->name;
181 args->out_numargs = 1;
182 args->out_args[0].size = sizeof(struct fuse_entry_out);
183 args->out_args[0].value = outarg;
184}
185
186/*
187 * Check whether the dentry is still valid
188 *
189 * If the entry validity timeout has expired and the dentry is
190 * positive, try to redo the lookup. If the lookup results in a
191 * different inode, then let the VFS invalidate the dentry and redo
192 * the lookup once more. If the lookup results in the same inode,
193 * then refresh the attributes, timeouts and mark the dentry valid.
194 */
195static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
196{
197 struct inode *inode;
198 struct dentry *parent;
199 struct fuse_mount *fm;
200 struct fuse_inode *fi;
201 int ret;
202
203 inode = d_inode_rcu(entry);
204 if (inode && fuse_is_bad(inode))
205 goto invalid;
206 else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
207 (flags & (LOOKUP_EXCL | LOOKUP_REVAL | LOOKUP_RENAME_TARGET))) {
208 struct fuse_entry_out outarg;
209 FUSE_ARGS(args);
210 struct fuse_forget_link *forget;
211 u64 attr_version;
212
213 /* For negative dentries, always do a fresh lookup */
214 if (!inode)
215 goto invalid;
216
217 ret = -ECHILD;
218 if (flags & LOOKUP_RCU)
219 goto out;
220
221 fm = get_fuse_mount(inode);
222
223 forget = fuse_alloc_forget();
224 ret = -ENOMEM;
225 if (!forget)
226 goto out;
227
228 attr_version = fuse_get_attr_version(fm->fc);
229
230 parent = dget_parent(entry);
231 fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
232 &entry->d_name, &outarg);
233 ret = fuse_simple_request(fm, &args);
234 dput(parent);
235 /* Zero nodeid is same as -ENOENT */
236 if (!ret && !outarg.nodeid)
237 ret = -ENOENT;
238 if (!ret) {
239 fi = get_fuse_inode(inode);
240 if (outarg.nodeid != get_node_id(inode) ||
241 (bool) IS_AUTOMOUNT(inode) != (bool) (outarg.attr.flags & FUSE_ATTR_SUBMOUNT)) {
242 fuse_queue_forget(fm->fc, forget,
243 outarg.nodeid, 1);
244 goto invalid;
245 }
246 spin_lock(&fi->lock);
247 fi->nlookup++;
248 spin_unlock(&fi->lock);
249 }
250 kfree(forget);
251 if (ret == -ENOMEM || ret == -EINTR)
252 goto out;
253 if (ret || fuse_invalid_attr(&outarg.attr) ||
254 fuse_stale_inode(inode, outarg.generation, &outarg.attr))
255 goto invalid;
256
257 forget_all_cached_acls(inode);
258 fuse_change_attributes(inode, &outarg.attr, NULL,
259 ATTR_TIMEOUT(&outarg),
260 attr_version);
261 fuse_change_entry_timeout(entry, &outarg);
262 } else if (inode) {
263 fi = get_fuse_inode(inode);
264 if (flags & LOOKUP_RCU) {
265 if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
266 return -ECHILD;
267 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
268 parent = dget_parent(entry);
269 fuse_advise_use_readdirplus(d_inode(parent));
270 dput(parent);
271 }
272 }
273 ret = 1;
274out:
275 return ret;
276
277invalid:
278 ret = 0;
279 goto out;
280}
281
282#if BITS_PER_LONG < 64
283static int fuse_dentry_init(struct dentry *dentry)
284{
285 dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry),
286 GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
287
288 return dentry->d_fsdata ? 0 : -ENOMEM;
289}
290static void fuse_dentry_release(struct dentry *dentry)
291{
292 union fuse_dentry *fd = dentry->d_fsdata;
293
294 kfree_rcu(fd, rcu);
295}
296#endif
297
298static int fuse_dentry_delete(const struct dentry *dentry)
299{
300 return time_before64(fuse_dentry_time(dentry), get_jiffies_64());
301}
302
303/*
304 * Create a fuse_mount object with a new superblock (with path->dentry
305 * as the root), and return that mount so it can be auto-mounted on
306 * @path.
307 */
308static struct vfsmount *fuse_dentry_automount(struct path *path)
309{
310 struct fs_context *fsc;
311 struct vfsmount *mnt;
312 struct fuse_inode *mp_fi = get_fuse_inode(d_inode(path->dentry));
313
314 fsc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry);
315 if (IS_ERR(fsc))
316 return ERR_CAST(fsc);
317
318 /* Pass the FUSE inode of the mount for fuse_get_tree_submount() */
319 fsc->fs_private = mp_fi;
320
321 /* Create the submount */
322 mnt = fc_mount(fsc);
323 if (!IS_ERR(mnt))
324 mntget(mnt);
325
326 put_fs_context(fsc);
327 return mnt;
328}
329
330const struct dentry_operations fuse_dentry_operations = {
331 .d_revalidate = fuse_dentry_revalidate,
332 .d_delete = fuse_dentry_delete,
333#if BITS_PER_LONG < 64
334 .d_init = fuse_dentry_init,
335 .d_release = fuse_dentry_release,
336#endif
337 .d_automount = fuse_dentry_automount,
338};
339
340const struct dentry_operations fuse_root_dentry_operations = {
341#if BITS_PER_LONG < 64
342 .d_init = fuse_dentry_init,
343 .d_release = fuse_dentry_release,
344#endif
345};
346
347int fuse_valid_type(int m)
348{
349 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
350 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
351}
352
353static bool fuse_valid_size(u64 size)
354{
355 return size <= LLONG_MAX;
356}
357
358bool fuse_invalid_attr(struct fuse_attr *attr)
359{
360 return !fuse_valid_type(attr->mode) || !fuse_valid_size(attr->size);
361}
362
363int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
364 struct fuse_entry_out *outarg, struct inode **inode)
365{
366 struct fuse_mount *fm = get_fuse_mount_super(sb);
367 FUSE_ARGS(args);
368 struct fuse_forget_link *forget;
369 u64 attr_version;
370 int err;
371
372 *inode = NULL;
373 err = -ENAMETOOLONG;
374 if (name->len > FUSE_NAME_MAX)
375 goto out;
376
377
378 forget = fuse_alloc_forget();
379 err = -ENOMEM;
380 if (!forget)
381 goto out;
382
383 attr_version = fuse_get_attr_version(fm->fc);
384
385 fuse_lookup_init(fm->fc, &args, nodeid, name, outarg);
386 err = fuse_simple_request(fm, &args);
387 /* Zero nodeid is same as -ENOENT, but with valid timeout */
388 if (err || !outarg->nodeid)
389 goto out_put_forget;
390
391 err = -EIO;
392 if (fuse_invalid_attr(&outarg->attr))
393 goto out_put_forget;
394 if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) {
395 pr_warn_once("root generation should be zero\n");
396 outarg->generation = 0;
397 }
398
399 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
400 &outarg->attr, ATTR_TIMEOUT(outarg),
401 attr_version);
402 err = -ENOMEM;
403 if (!*inode) {
404 fuse_queue_forget(fm->fc, forget, outarg->nodeid, 1);
405 goto out;
406 }
407 err = 0;
408
409 out_put_forget:
410 kfree(forget);
411 out:
412 return err;
413}
414
415static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
416 unsigned int flags)
417{
418 int err;
419 struct fuse_entry_out outarg;
420 struct inode *inode;
421 struct dentry *newent;
422 bool outarg_valid = true;
423 bool locked;
424
425 if (fuse_is_bad(dir))
426 return ERR_PTR(-EIO);
427
428 locked = fuse_lock_inode(dir);
429 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
430 &outarg, &inode);
431 fuse_unlock_inode(dir, locked);
432 if (err == -ENOENT) {
433 outarg_valid = false;
434 err = 0;
435 }
436 if (err)
437 goto out_err;
438
439 err = -EIO;
440 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
441 goto out_iput;
442
443 newent = d_splice_alias(inode, entry);
444 err = PTR_ERR(newent);
445 if (IS_ERR(newent))
446 goto out_err;
447
448 entry = newent ? newent : entry;
449 if (outarg_valid)
450 fuse_change_entry_timeout(entry, &outarg);
451 else
452 fuse_invalidate_entry_cache(entry);
453
454 if (inode)
455 fuse_advise_use_readdirplus(dir);
456 return newent;
457
458 out_iput:
459 iput(inode);
460 out_err:
461 return ERR_PTR(err);
462}
463
464static int get_security_context(struct dentry *entry, umode_t mode,
465 struct fuse_in_arg *ext)
466{
467 struct fuse_secctx *fctx;
468 struct fuse_secctx_header *header;
469 void *ctx = NULL, *ptr;
470 u32 ctxlen, total_len = sizeof(*header);
471 int err, nr_ctx = 0;
472 const char *name;
473 size_t namelen;
474
475 err = security_dentry_init_security(entry, mode, &entry->d_name,
476 &name, &ctx, &ctxlen);
477 if (err) {
478 if (err != -EOPNOTSUPP)
479 goto out_err;
480 /* No LSM is supporting this security hook. Ignore error */
481 ctxlen = 0;
482 ctx = NULL;
483 }
484
485 if (ctxlen) {
486 nr_ctx = 1;
487 namelen = strlen(name) + 1;
488 err = -EIO;
489 if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
490 goto out_err;
491 total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
492 }
493
494 err = -ENOMEM;
495 header = ptr = kzalloc(total_len, GFP_KERNEL);
496 if (!ptr)
497 goto out_err;
498
499 header->nr_secctx = nr_ctx;
500 header->size = total_len;
501 ptr += sizeof(*header);
502 if (nr_ctx) {
503 fctx = ptr;
504 fctx->size = ctxlen;
505 ptr += sizeof(*fctx);
506
507 strcpy(ptr, name);
508 ptr += namelen;
509
510 memcpy(ptr, ctx, ctxlen);
511 }
512 ext->size = total_len;
513 ext->value = header;
514 err = 0;
515out_err:
516 kfree(ctx);
517 return err;
518}
519
520static void *extend_arg(struct fuse_in_arg *buf, u32 bytes)
521{
522 void *p;
523 u32 newlen = buf->size + bytes;
524
525 p = krealloc(buf->value, newlen, GFP_KERNEL);
526 if (!p) {
527 kfree(buf->value);
528 buf->size = 0;
529 buf->value = NULL;
530 return NULL;
531 }
532
533 memset(p + buf->size, 0, bytes);
534 buf->value = p;
535 buf->size = newlen;
536
537 return p + newlen - bytes;
538}
539
540static u32 fuse_ext_size(size_t size)
541{
542 return FUSE_REC_ALIGN(sizeof(struct fuse_ext_header) + size);
543}
544
545/*
546 * This adds just a single supplementary group that matches the parent's group.
547 */
548static int get_create_supp_group(struct inode *dir, struct fuse_in_arg *ext)
549{
550 struct fuse_conn *fc = get_fuse_conn(dir);
551 struct fuse_ext_header *xh;
552 struct fuse_supp_groups *sg;
553 kgid_t kgid = dir->i_gid;
554 gid_t parent_gid = from_kgid(fc->user_ns, kgid);
555 u32 sg_len = fuse_ext_size(sizeof(*sg) + sizeof(sg->groups[0]));
556
557 if (parent_gid == (gid_t) -1 || gid_eq(kgid, current_fsgid()) ||
558 !in_group_p(kgid))
559 return 0;
560
561 xh = extend_arg(ext, sg_len);
562 if (!xh)
563 return -ENOMEM;
564
565 xh->size = sg_len;
566 xh->type = FUSE_EXT_GROUPS;
567
568 sg = (struct fuse_supp_groups *) &xh[1];
569 sg->nr_groups = 1;
570 sg->groups[0] = parent_gid;
571
572 return 0;
573}
574
575static int get_create_ext(struct fuse_args *args,
576 struct inode *dir, struct dentry *dentry,
577 umode_t mode)
578{
579 struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
580 struct fuse_in_arg ext = { .size = 0, .value = NULL };
581 int err = 0;
582
583 if (fc->init_security)
584 err = get_security_context(dentry, mode, &ext);
585 if (!err && fc->create_supp_group)
586 err = get_create_supp_group(dir, &ext);
587
588 if (!err && ext.size) {
589 WARN_ON(args->in_numargs >= ARRAY_SIZE(args->in_args));
590 args->is_ext = true;
591 args->ext_idx = args->in_numargs++;
592 args->in_args[args->ext_idx] = ext;
593 } else {
594 kfree(ext.value);
595 }
596
597 return err;
598}
599
600static void free_ext_value(struct fuse_args *args)
601{
602 if (args->is_ext)
603 kfree(args->in_args[args->ext_idx].value);
604}
605
606/*
607 * Atomic create+open operation
608 *
609 * If the filesystem doesn't support this, then fall back to separate
610 * 'mknod' + 'open' requests.
611 */
612static int fuse_create_open(struct inode *dir, struct dentry *entry,
613 struct file *file, unsigned int flags,
614 umode_t mode, u32 opcode)
615{
616 int err;
617 struct inode *inode;
618 struct fuse_mount *fm = get_fuse_mount(dir);
619 FUSE_ARGS(args);
620 struct fuse_forget_link *forget;
621 struct fuse_create_in inarg;
622 struct fuse_open_out *outopenp;
623 struct fuse_entry_out outentry;
624 struct fuse_inode *fi;
625 struct fuse_file *ff;
626 bool trunc = flags & O_TRUNC;
627
628 /* Userspace expects S_IFREG in create mode */
629 BUG_ON((mode & S_IFMT) != S_IFREG);
630
631 forget = fuse_alloc_forget();
632 err = -ENOMEM;
633 if (!forget)
634 goto out_err;
635
636 err = -ENOMEM;
637 ff = fuse_file_alloc(fm, true);
638 if (!ff)
639 goto out_put_forget_req;
640
641 if (!fm->fc->dont_mask)
642 mode &= ~current_umask();
643
644 flags &= ~O_NOCTTY;
645 memset(&inarg, 0, sizeof(inarg));
646 memset(&outentry, 0, sizeof(outentry));
647 inarg.flags = flags;
648 inarg.mode = mode;
649 inarg.umask = current_umask();
650
651 if (fm->fc->handle_killpriv_v2 && trunc &&
652 !(flags & O_EXCL) && !capable(CAP_FSETID)) {
653 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
654 }
655
656 args.opcode = opcode;
657 args.nodeid = get_node_id(dir);
658 args.in_numargs = 2;
659 args.in_args[0].size = sizeof(inarg);
660 args.in_args[0].value = &inarg;
661 args.in_args[1].size = entry->d_name.len + 1;
662 args.in_args[1].value = entry->d_name.name;
663 args.out_numargs = 2;
664 args.out_args[0].size = sizeof(outentry);
665 args.out_args[0].value = &outentry;
666 /* Store outarg for fuse_finish_open() */
667 outopenp = &ff->args->open_outarg;
668 args.out_args[1].size = sizeof(*outopenp);
669 args.out_args[1].value = outopenp;
670
671 err = get_create_ext(&args, dir, entry, mode);
672 if (err)
673 goto out_put_forget_req;
674
675 err = fuse_simple_request(fm, &args);
676 free_ext_value(&args);
677 if (err)
678 goto out_free_ff;
679
680 err = -EIO;
681 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
682 fuse_invalid_attr(&outentry.attr))
683 goto out_free_ff;
684
685 ff->fh = outopenp->fh;
686 ff->nodeid = outentry.nodeid;
687 ff->open_flags = outopenp->open_flags;
688 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
689 &outentry.attr, ATTR_TIMEOUT(&outentry), 0);
690 if (!inode) {
691 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
692 fuse_sync_release(NULL, ff, flags);
693 fuse_queue_forget(fm->fc, forget, outentry.nodeid, 1);
694 err = -ENOMEM;
695 goto out_err;
696 }
697 kfree(forget);
698 d_instantiate(entry, inode);
699 fuse_change_entry_timeout(entry, &outentry);
700 fuse_dir_changed(dir);
701 err = generic_file_open(inode, file);
702 if (!err) {
703 file->private_data = ff;
704 err = finish_open(file, entry, fuse_finish_open);
705 }
706 if (err) {
707 fi = get_fuse_inode(inode);
708 fuse_sync_release(fi, ff, flags);
709 } else {
710 if (fm->fc->atomic_o_trunc && trunc)
711 truncate_pagecache(inode, 0);
712 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
713 invalidate_inode_pages2(inode->i_mapping);
714 }
715 return err;
716
717out_free_ff:
718 fuse_file_free(ff);
719out_put_forget_req:
720 kfree(forget);
721out_err:
722 return err;
723}
724
725static int fuse_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
726 umode_t, dev_t);
727static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
728 struct file *file, unsigned flags,
729 umode_t mode)
730{
731 int err;
732 struct fuse_conn *fc = get_fuse_conn(dir);
733 struct dentry *res = NULL;
734
735 if (fuse_is_bad(dir))
736 return -EIO;
737
738 if (d_in_lookup(entry)) {
739 res = fuse_lookup(dir, entry, 0);
740 if (IS_ERR(res))
741 return PTR_ERR(res);
742
743 if (res)
744 entry = res;
745 }
746
747 if (!(flags & O_CREAT) || d_really_is_positive(entry))
748 goto no_open;
749
750 /* Only creates */
751 file->f_mode |= FMODE_CREATED;
752
753 if (fc->no_create)
754 goto mknod;
755
756 err = fuse_create_open(dir, entry, file, flags, mode, FUSE_CREATE);
757 if (err == -ENOSYS) {
758 fc->no_create = 1;
759 goto mknod;
760 } else if (err == -EEXIST)
761 fuse_invalidate_entry(entry);
762out_dput:
763 dput(res);
764 return err;
765
766mknod:
767 err = fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
768 if (err)
769 goto out_dput;
770no_open:
771 return finish_no_open(file, res);
772}
773
774/*
775 * Code shared between mknod, mkdir, symlink and link
776 */
777static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
778 struct inode *dir, struct dentry *entry,
779 umode_t mode)
780{
781 struct fuse_entry_out outarg;
782 struct inode *inode;
783 struct dentry *d;
784 int err;
785 struct fuse_forget_link *forget;
786
787 if (fuse_is_bad(dir))
788 return -EIO;
789
790 forget = fuse_alloc_forget();
791 if (!forget)
792 return -ENOMEM;
793
794 memset(&outarg, 0, sizeof(outarg));
795 args->nodeid = get_node_id(dir);
796 args->out_numargs = 1;
797 args->out_args[0].size = sizeof(outarg);
798 args->out_args[0].value = &outarg;
799
800 if (args->opcode != FUSE_LINK) {
801 err = get_create_ext(args, dir, entry, mode);
802 if (err)
803 goto out_put_forget_req;
804 }
805
806 err = fuse_simple_request(fm, args);
807 free_ext_value(args);
808 if (err)
809 goto out_put_forget_req;
810
811 err = -EIO;
812 if (invalid_nodeid(outarg.nodeid) || fuse_invalid_attr(&outarg.attr))
813 goto out_put_forget_req;
814
815 if ((outarg.attr.mode ^ mode) & S_IFMT)
816 goto out_put_forget_req;
817
818 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
819 &outarg.attr, ATTR_TIMEOUT(&outarg), 0);
820 if (!inode) {
821 fuse_queue_forget(fm->fc, forget, outarg.nodeid, 1);
822 return -ENOMEM;
823 }
824 kfree(forget);
825
826 d_drop(entry);
827 d = d_splice_alias(inode, entry);
828 if (IS_ERR(d))
829 return PTR_ERR(d);
830
831 if (d) {
832 fuse_change_entry_timeout(d, &outarg);
833 dput(d);
834 } else {
835 fuse_change_entry_timeout(entry, &outarg);
836 }
837 fuse_dir_changed(dir);
838 return 0;
839
840 out_put_forget_req:
841 if (err == -EEXIST)
842 fuse_invalidate_entry(entry);
843 kfree(forget);
844 return err;
845}
846
847static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
848 struct dentry *entry, umode_t mode, dev_t rdev)
849{
850 struct fuse_mknod_in inarg;
851 struct fuse_mount *fm = get_fuse_mount(dir);
852 FUSE_ARGS(args);
853
854 if (!fm->fc->dont_mask)
855 mode &= ~current_umask();
856
857 memset(&inarg, 0, sizeof(inarg));
858 inarg.mode = mode;
859 inarg.rdev = new_encode_dev(rdev);
860 inarg.umask = current_umask();
861 args.opcode = FUSE_MKNOD;
862 args.in_numargs = 2;
863 args.in_args[0].size = sizeof(inarg);
864 args.in_args[0].value = &inarg;
865 args.in_args[1].size = entry->d_name.len + 1;
866 args.in_args[1].value = entry->d_name.name;
867 return create_new_entry(fm, &args, dir, entry, mode);
868}
869
870static int fuse_create(struct mnt_idmap *idmap, struct inode *dir,
871 struct dentry *entry, umode_t mode, bool excl)
872{
873 return fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
874}
875
876static int fuse_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
877 struct file *file, umode_t mode)
878{
879 struct fuse_conn *fc = get_fuse_conn(dir);
880 int err;
881
882 if (fc->no_tmpfile)
883 return -EOPNOTSUPP;
884
885 err = fuse_create_open(dir, file->f_path.dentry, file, file->f_flags, mode, FUSE_TMPFILE);
886 if (err == -ENOSYS) {
887 fc->no_tmpfile = 1;
888 err = -EOPNOTSUPP;
889 }
890 return err;
891}
892
893static int fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
894 struct dentry *entry, umode_t mode)
895{
896 struct fuse_mkdir_in inarg;
897 struct fuse_mount *fm = get_fuse_mount(dir);
898 FUSE_ARGS(args);
899
900 if (!fm->fc->dont_mask)
901 mode &= ~current_umask();
902
903 memset(&inarg, 0, sizeof(inarg));
904 inarg.mode = mode;
905 inarg.umask = current_umask();
906 args.opcode = FUSE_MKDIR;
907 args.in_numargs = 2;
908 args.in_args[0].size = sizeof(inarg);
909 args.in_args[0].value = &inarg;
910 args.in_args[1].size = entry->d_name.len + 1;
911 args.in_args[1].value = entry->d_name.name;
912 return create_new_entry(fm, &args, dir, entry, S_IFDIR);
913}
914
915static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
916 struct dentry *entry, const char *link)
917{
918 struct fuse_mount *fm = get_fuse_mount(dir);
919 unsigned len = strlen(link) + 1;
920 FUSE_ARGS(args);
921
922 args.opcode = FUSE_SYMLINK;
923 args.in_numargs = 2;
924 args.in_args[0].size = entry->d_name.len + 1;
925 args.in_args[0].value = entry->d_name.name;
926 args.in_args[1].size = len;
927 args.in_args[1].value = link;
928 return create_new_entry(fm, &args, dir, entry, S_IFLNK);
929}
930
931void fuse_flush_time_update(struct inode *inode)
932{
933 int err = sync_inode_metadata(inode, 1);
934
935 mapping_set_error(inode->i_mapping, err);
936}
937
938static void fuse_update_ctime_in_cache(struct inode *inode)
939{
940 if (!IS_NOCMTIME(inode)) {
941 inode_set_ctime_current(inode);
942 mark_inode_dirty_sync(inode);
943 fuse_flush_time_update(inode);
944 }
945}
946
947void fuse_update_ctime(struct inode *inode)
948{
949 fuse_invalidate_attr_mask(inode, STATX_CTIME);
950 fuse_update_ctime_in_cache(inode);
951}
952
953static void fuse_entry_unlinked(struct dentry *entry)
954{
955 struct inode *inode = d_inode(entry);
956 struct fuse_conn *fc = get_fuse_conn(inode);
957 struct fuse_inode *fi = get_fuse_inode(inode);
958
959 spin_lock(&fi->lock);
960 fi->attr_version = atomic64_inc_return(&fc->attr_version);
961 /*
962 * If i_nlink == 0 then unlink doesn't make sense, yet this can
963 * happen if userspace filesystem is careless. It would be
964 * difficult to enforce correct nlink usage so just ignore this
965 * condition here
966 */
967 if (S_ISDIR(inode->i_mode))
968 clear_nlink(inode);
969 else if (inode->i_nlink > 0)
970 drop_nlink(inode);
971 spin_unlock(&fi->lock);
972 fuse_invalidate_entry_cache(entry);
973 fuse_update_ctime(inode);
974}
975
976static int fuse_unlink(struct inode *dir, struct dentry *entry)
977{
978 int err;
979 struct fuse_mount *fm = get_fuse_mount(dir);
980 FUSE_ARGS(args);
981
982 if (fuse_is_bad(dir))
983 return -EIO;
984
985 args.opcode = FUSE_UNLINK;
986 args.nodeid = get_node_id(dir);
987 args.in_numargs = 1;
988 args.in_args[0].size = entry->d_name.len + 1;
989 args.in_args[0].value = entry->d_name.name;
990 err = fuse_simple_request(fm, &args);
991 if (!err) {
992 fuse_dir_changed(dir);
993 fuse_entry_unlinked(entry);
994 } else if (err == -EINTR || err == -ENOENT)
995 fuse_invalidate_entry(entry);
996 return err;
997}
998
999static int fuse_rmdir(struct inode *dir, struct dentry *entry)
1000{
1001 int err;
1002 struct fuse_mount *fm = get_fuse_mount(dir);
1003 FUSE_ARGS(args);
1004
1005 if (fuse_is_bad(dir))
1006 return -EIO;
1007
1008 args.opcode = FUSE_RMDIR;
1009 args.nodeid = get_node_id(dir);
1010 args.in_numargs = 1;
1011 args.in_args[0].size = entry->d_name.len + 1;
1012 args.in_args[0].value = entry->d_name.name;
1013 err = fuse_simple_request(fm, &args);
1014 if (!err) {
1015 fuse_dir_changed(dir);
1016 fuse_entry_unlinked(entry);
1017 } else if (err == -EINTR || err == -ENOENT)
1018 fuse_invalidate_entry(entry);
1019 return err;
1020}
1021
1022static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
1023 struct inode *newdir, struct dentry *newent,
1024 unsigned int flags, int opcode, size_t argsize)
1025{
1026 int err;
1027 struct fuse_rename2_in inarg;
1028 struct fuse_mount *fm = get_fuse_mount(olddir);
1029 FUSE_ARGS(args);
1030
1031 memset(&inarg, 0, argsize);
1032 inarg.newdir = get_node_id(newdir);
1033 inarg.flags = flags;
1034 args.opcode = opcode;
1035 args.nodeid = get_node_id(olddir);
1036 args.in_numargs = 3;
1037 args.in_args[0].size = argsize;
1038 args.in_args[0].value = &inarg;
1039 args.in_args[1].size = oldent->d_name.len + 1;
1040 args.in_args[1].value = oldent->d_name.name;
1041 args.in_args[2].size = newent->d_name.len + 1;
1042 args.in_args[2].value = newent->d_name.name;
1043 err = fuse_simple_request(fm, &args);
1044 if (!err) {
1045 /* ctime changes */
1046 fuse_update_ctime(d_inode(oldent));
1047
1048 if (flags & RENAME_EXCHANGE)
1049 fuse_update_ctime(d_inode(newent));
1050
1051 fuse_dir_changed(olddir);
1052 if (olddir != newdir)
1053 fuse_dir_changed(newdir);
1054
1055 /* newent will end up negative */
1056 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent))
1057 fuse_entry_unlinked(newent);
1058 } else if (err == -EINTR || err == -ENOENT) {
1059 /* If request was interrupted, DEITY only knows if the
1060 rename actually took place. If the invalidation
1061 fails (e.g. some process has CWD under the renamed
1062 directory), then there can be inconsistency between
1063 the dcache and the real filesystem. Tough luck. */
1064 fuse_invalidate_entry(oldent);
1065 if (d_really_is_positive(newent))
1066 fuse_invalidate_entry(newent);
1067 }
1068
1069 return err;
1070}
1071
1072static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
1073 struct dentry *oldent, struct inode *newdir,
1074 struct dentry *newent, unsigned int flags)
1075{
1076 struct fuse_conn *fc = get_fuse_conn(olddir);
1077 int err;
1078
1079 if (fuse_is_bad(olddir))
1080 return -EIO;
1081
1082 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
1083 return -EINVAL;
1084
1085 if (flags) {
1086 if (fc->no_rename2 || fc->minor < 23)
1087 return -EINVAL;
1088
1089 err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
1090 FUSE_RENAME2,
1091 sizeof(struct fuse_rename2_in));
1092 if (err == -ENOSYS) {
1093 fc->no_rename2 = 1;
1094 err = -EINVAL;
1095 }
1096 } else {
1097 err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
1098 FUSE_RENAME,
1099 sizeof(struct fuse_rename_in));
1100 }
1101
1102 return err;
1103}
1104
1105static int fuse_link(struct dentry *entry, struct inode *newdir,
1106 struct dentry *newent)
1107{
1108 int err;
1109 struct fuse_link_in inarg;
1110 struct inode *inode = d_inode(entry);
1111 struct fuse_mount *fm = get_fuse_mount(inode);
1112 FUSE_ARGS(args);
1113
1114 memset(&inarg, 0, sizeof(inarg));
1115 inarg.oldnodeid = get_node_id(inode);
1116 args.opcode = FUSE_LINK;
1117 args.in_numargs = 2;
1118 args.in_args[0].size = sizeof(inarg);
1119 args.in_args[0].value = &inarg;
1120 args.in_args[1].size = newent->d_name.len + 1;
1121 args.in_args[1].value = newent->d_name.name;
1122 err = create_new_entry(fm, &args, newdir, newent, inode->i_mode);
1123 if (!err)
1124 fuse_update_ctime_in_cache(inode);
1125 else if (err == -EINTR)
1126 fuse_invalidate_attr(inode);
1127
1128 return err;
1129}
1130
1131static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
1132 struct kstat *stat)
1133{
1134 unsigned int blkbits;
1135 struct fuse_conn *fc = get_fuse_conn(inode);
1136
1137 stat->dev = inode->i_sb->s_dev;
1138 stat->ino = attr->ino;
1139 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
1140 stat->nlink = attr->nlink;
1141 stat->uid = make_kuid(fc->user_ns, attr->uid);
1142 stat->gid = make_kgid(fc->user_ns, attr->gid);
1143 stat->rdev = inode->i_rdev;
1144 stat->atime.tv_sec = attr->atime;
1145 stat->atime.tv_nsec = attr->atimensec;
1146 stat->mtime.tv_sec = attr->mtime;
1147 stat->mtime.tv_nsec = attr->mtimensec;
1148 stat->ctime.tv_sec = attr->ctime;
1149 stat->ctime.tv_nsec = attr->ctimensec;
1150 stat->size = attr->size;
1151 stat->blocks = attr->blocks;
1152
1153 if (attr->blksize != 0)
1154 blkbits = ilog2(attr->blksize);
1155 else
1156 blkbits = inode->i_sb->s_blocksize_bits;
1157
1158 stat->blksize = 1 << blkbits;
1159}
1160
1161static void fuse_statx_to_attr(struct fuse_statx *sx, struct fuse_attr *attr)
1162{
1163 memset(attr, 0, sizeof(*attr));
1164 attr->ino = sx->ino;
1165 attr->size = sx->size;
1166 attr->blocks = sx->blocks;
1167 attr->atime = sx->atime.tv_sec;
1168 attr->mtime = sx->mtime.tv_sec;
1169 attr->ctime = sx->ctime.tv_sec;
1170 attr->atimensec = sx->atime.tv_nsec;
1171 attr->mtimensec = sx->mtime.tv_nsec;
1172 attr->ctimensec = sx->ctime.tv_nsec;
1173 attr->mode = sx->mode;
1174 attr->nlink = sx->nlink;
1175 attr->uid = sx->uid;
1176 attr->gid = sx->gid;
1177 attr->rdev = new_encode_dev(MKDEV(sx->rdev_major, sx->rdev_minor));
1178 attr->blksize = sx->blksize;
1179}
1180
1181static int fuse_do_statx(struct inode *inode, struct file *file,
1182 struct kstat *stat)
1183{
1184 int err;
1185 struct fuse_attr attr;
1186 struct fuse_statx *sx;
1187 struct fuse_statx_in inarg;
1188 struct fuse_statx_out outarg;
1189 struct fuse_mount *fm = get_fuse_mount(inode);
1190 u64 attr_version = fuse_get_attr_version(fm->fc);
1191 FUSE_ARGS(args);
1192
1193 memset(&inarg, 0, sizeof(inarg));
1194 memset(&outarg, 0, sizeof(outarg));
1195 /* Directories have separate file-handle space */
1196 if (file && S_ISREG(inode->i_mode)) {
1197 struct fuse_file *ff = file->private_data;
1198
1199 inarg.getattr_flags |= FUSE_GETATTR_FH;
1200 inarg.fh = ff->fh;
1201 }
1202 /* For now leave sync hints as the default, request all stats. */
1203 inarg.sx_flags = 0;
1204 inarg.sx_mask = STATX_BASIC_STATS | STATX_BTIME;
1205 args.opcode = FUSE_STATX;
1206 args.nodeid = get_node_id(inode);
1207 args.in_numargs = 1;
1208 args.in_args[0].size = sizeof(inarg);
1209 args.in_args[0].value = &inarg;
1210 args.out_numargs = 1;
1211 args.out_args[0].size = sizeof(outarg);
1212 args.out_args[0].value = &outarg;
1213 err = fuse_simple_request(fm, &args);
1214 if (err)
1215 return err;
1216
1217 sx = &outarg.stat;
1218 if (((sx->mask & STATX_SIZE) && !fuse_valid_size(sx->size)) ||
1219 ((sx->mask & STATX_TYPE) && (!fuse_valid_type(sx->mode) ||
1220 inode_wrong_type(inode, sx->mode)))) {
1221 fuse_make_bad(inode);
1222 return -EIO;
1223 }
1224
1225 fuse_statx_to_attr(&outarg.stat, &attr);
1226 if ((sx->mask & STATX_BASIC_STATS) == STATX_BASIC_STATS) {
1227 fuse_change_attributes(inode, &attr, &outarg.stat,
1228 ATTR_TIMEOUT(&outarg), attr_version);
1229 }
1230
1231 if (stat) {
1232 stat->result_mask = sx->mask & (STATX_BASIC_STATS | STATX_BTIME);
1233 stat->btime.tv_sec = sx->btime.tv_sec;
1234 stat->btime.tv_nsec = min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
1235 fuse_fillattr(inode, &attr, stat);
1236 stat->result_mask |= STATX_TYPE;
1237 }
1238
1239 return 0;
1240}
1241
1242static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
1243 struct file *file)
1244{
1245 int err;
1246 struct fuse_getattr_in inarg;
1247 struct fuse_attr_out outarg;
1248 struct fuse_mount *fm = get_fuse_mount(inode);
1249 FUSE_ARGS(args);
1250 u64 attr_version;
1251
1252 attr_version = fuse_get_attr_version(fm->fc);
1253
1254 memset(&inarg, 0, sizeof(inarg));
1255 memset(&outarg, 0, sizeof(outarg));
1256 /* Directories have separate file-handle space */
1257 if (file && S_ISREG(inode->i_mode)) {
1258 struct fuse_file *ff = file->private_data;
1259
1260 inarg.getattr_flags |= FUSE_GETATTR_FH;
1261 inarg.fh = ff->fh;
1262 }
1263 args.opcode = FUSE_GETATTR;
1264 args.nodeid = get_node_id(inode);
1265 args.in_numargs = 1;
1266 args.in_args[0].size = sizeof(inarg);
1267 args.in_args[0].value = &inarg;
1268 args.out_numargs = 1;
1269 args.out_args[0].size = sizeof(outarg);
1270 args.out_args[0].value = &outarg;
1271 err = fuse_simple_request(fm, &args);
1272 if (!err) {
1273 if (fuse_invalid_attr(&outarg.attr) ||
1274 inode_wrong_type(inode, outarg.attr.mode)) {
1275 fuse_make_bad(inode);
1276 err = -EIO;
1277 } else {
1278 fuse_change_attributes(inode, &outarg.attr, NULL,
1279 ATTR_TIMEOUT(&outarg),
1280 attr_version);
1281 if (stat)
1282 fuse_fillattr(inode, &outarg.attr, stat);
1283 }
1284 }
1285 return err;
1286}
1287
1288static int fuse_update_get_attr(struct inode *inode, struct file *file,
1289 struct kstat *stat, u32 request_mask,
1290 unsigned int flags)
1291{
1292 struct fuse_inode *fi = get_fuse_inode(inode);
1293 struct fuse_conn *fc = get_fuse_conn(inode);
1294 int err = 0;
1295 bool sync;
1296 u32 inval_mask = READ_ONCE(fi->inval_mask);
1297 u32 cache_mask = fuse_get_cache_mask(inode);
1298
1299
1300 /* FUSE only supports basic stats and possibly btime */
1301 request_mask &= STATX_BASIC_STATS | STATX_BTIME;
1302retry:
1303 if (fc->no_statx)
1304 request_mask &= STATX_BASIC_STATS;
1305
1306 if (!request_mask)
1307 sync = false;
1308 else if (flags & AT_STATX_FORCE_SYNC)
1309 sync = true;
1310 else if (flags & AT_STATX_DONT_SYNC)
1311 sync = false;
1312 else if (request_mask & inval_mask & ~cache_mask)
1313 sync = true;
1314 else
1315 sync = time_before64(fi->i_time, get_jiffies_64());
1316
1317 if (sync) {
1318 forget_all_cached_acls(inode);
1319 /* Try statx if BTIME is requested */
1320 if (!fc->no_statx && (request_mask & ~STATX_BASIC_STATS)) {
1321 err = fuse_do_statx(inode, file, stat);
1322 if (err == -ENOSYS) {
1323 fc->no_statx = 1;
1324 err = 0;
1325 goto retry;
1326 }
1327 } else {
1328 err = fuse_do_getattr(inode, stat, file);
1329 }
1330 } else if (stat) {
1331 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1332 stat->mode = fi->orig_i_mode;
1333 stat->ino = fi->orig_ino;
1334 if (test_bit(FUSE_I_BTIME, &fi->state)) {
1335 stat->btime = fi->i_btime;
1336 stat->result_mask |= STATX_BTIME;
1337 }
1338 }
1339
1340 return err;
1341}
1342
1343int fuse_update_attributes(struct inode *inode, struct file *file, u32 mask)
1344{
1345 return fuse_update_get_attr(inode, file, NULL, mask, 0);
1346}
1347
1348int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
1349 u64 child_nodeid, struct qstr *name, u32 flags)
1350{
1351 int err = -ENOTDIR;
1352 struct inode *parent;
1353 struct dentry *dir;
1354 struct dentry *entry;
1355
1356 parent = fuse_ilookup(fc, parent_nodeid, NULL);
1357 if (!parent)
1358 return -ENOENT;
1359
1360 inode_lock_nested(parent, I_MUTEX_PARENT);
1361 if (!S_ISDIR(parent->i_mode))
1362 goto unlock;
1363
1364 err = -ENOENT;
1365 dir = d_find_alias(parent);
1366 if (!dir)
1367 goto unlock;
1368
1369 name->hash = full_name_hash(dir, name->name, name->len);
1370 entry = d_lookup(dir, name);
1371 dput(dir);
1372 if (!entry)
1373 goto unlock;
1374
1375 fuse_dir_changed(parent);
1376 if (!(flags & FUSE_EXPIRE_ONLY))
1377 d_invalidate(entry);
1378 fuse_invalidate_entry_cache(entry);
1379
1380 if (child_nodeid != 0 && d_really_is_positive(entry)) {
1381 inode_lock(d_inode(entry));
1382 if (get_node_id(d_inode(entry)) != child_nodeid) {
1383 err = -ENOENT;
1384 goto badentry;
1385 }
1386 if (d_mountpoint(entry)) {
1387 err = -EBUSY;
1388 goto badentry;
1389 }
1390 if (d_is_dir(entry)) {
1391 shrink_dcache_parent(entry);
1392 if (!simple_empty(entry)) {
1393 err = -ENOTEMPTY;
1394 goto badentry;
1395 }
1396 d_inode(entry)->i_flags |= S_DEAD;
1397 }
1398 dont_mount(entry);
1399 clear_nlink(d_inode(entry));
1400 err = 0;
1401 badentry:
1402 inode_unlock(d_inode(entry));
1403 if (!err)
1404 d_delete(entry);
1405 } else {
1406 err = 0;
1407 }
1408 dput(entry);
1409
1410 unlock:
1411 inode_unlock(parent);
1412 iput(parent);
1413 return err;
1414}
1415
1416static inline bool fuse_permissible_uidgid(struct fuse_conn *fc)
1417{
1418 const struct cred *cred = current_cred();
1419
1420 return (uid_eq(cred->euid, fc->user_id) &&
1421 uid_eq(cred->suid, fc->user_id) &&
1422 uid_eq(cred->uid, fc->user_id) &&
1423 gid_eq(cred->egid, fc->group_id) &&
1424 gid_eq(cred->sgid, fc->group_id) &&
1425 gid_eq(cred->gid, fc->group_id));
1426}
1427
1428/*
1429 * Calling into a user-controlled filesystem gives the filesystem
1430 * daemon ptrace-like capabilities over the current process. This
1431 * means, that the filesystem daemon is able to record the exact
1432 * filesystem operations performed, and can also control the behavior
1433 * of the requester process in otherwise impossible ways. For example
1434 * it can delay the operation for arbitrary length of time allowing
1435 * DoS against the requester.
1436 *
1437 * For this reason only those processes can call into the filesystem,
1438 * for which the owner of the mount has ptrace privilege. This
1439 * excludes processes started by other users, suid or sgid processes.
1440 */
1441bool fuse_allow_current_process(struct fuse_conn *fc)
1442{
1443 bool allow;
1444
1445 if (fc->allow_other)
1446 allow = current_in_userns(fc->user_ns);
1447 else
1448 allow = fuse_permissible_uidgid(fc);
1449
1450 if (!allow && allow_sys_admin_access && capable(CAP_SYS_ADMIN))
1451 allow = true;
1452
1453 return allow;
1454}
1455
1456static int fuse_access(struct inode *inode, int mask)
1457{
1458 struct fuse_mount *fm = get_fuse_mount(inode);
1459 FUSE_ARGS(args);
1460 struct fuse_access_in inarg;
1461 int err;
1462
1463 BUG_ON(mask & MAY_NOT_BLOCK);
1464
1465 if (fm->fc->no_access)
1466 return 0;
1467
1468 memset(&inarg, 0, sizeof(inarg));
1469 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1470 args.opcode = FUSE_ACCESS;
1471 args.nodeid = get_node_id(inode);
1472 args.in_numargs = 1;
1473 args.in_args[0].size = sizeof(inarg);
1474 args.in_args[0].value = &inarg;
1475 err = fuse_simple_request(fm, &args);
1476 if (err == -ENOSYS) {
1477 fm->fc->no_access = 1;
1478 err = 0;
1479 }
1480 return err;
1481}
1482
1483static int fuse_perm_getattr(struct inode *inode, int mask)
1484{
1485 if (mask & MAY_NOT_BLOCK)
1486 return -ECHILD;
1487
1488 forget_all_cached_acls(inode);
1489 return fuse_do_getattr(inode, NULL, NULL);
1490}
1491
1492/*
1493 * Check permission. The two basic access models of FUSE are:
1494 *
1495 * 1) Local access checking ('default_permissions' mount option) based
1496 * on file mode. This is the plain old disk filesystem permission
1497 * model.
1498 *
1499 * 2) "Remote" access checking, where server is responsible for
1500 * checking permission in each inode operation. An exception to this
1501 * is if ->permission() was invoked from sys_access() in which case an
1502 * access request is sent. Execute permission is still checked
1503 * locally based on file mode.
1504 */
1505static int fuse_permission(struct mnt_idmap *idmap,
1506 struct inode *inode, int mask)
1507{
1508 struct fuse_conn *fc = get_fuse_conn(inode);
1509 bool refreshed = false;
1510 int err = 0;
1511
1512 if (fuse_is_bad(inode))
1513 return -EIO;
1514
1515 if (!fuse_allow_current_process(fc))
1516 return -EACCES;
1517
1518 /*
1519 * If attributes are needed, refresh them before proceeding
1520 */
1521 if (fc->default_permissions ||
1522 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1523 struct fuse_inode *fi = get_fuse_inode(inode);
1524 u32 perm_mask = STATX_MODE | STATX_UID | STATX_GID;
1525
1526 if (perm_mask & READ_ONCE(fi->inval_mask) ||
1527 time_before64(fi->i_time, get_jiffies_64())) {
1528 refreshed = true;
1529
1530 err = fuse_perm_getattr(inode, mask);
1531 if (err)
1532 return err;
1533 }
1534 }
1535
1536 if (fc->default_permissions) {
1537 err = generic_permission(&nop_mnt_idmap, inode, mask);
1538
1539 /* If permission is denied, try to refresh file
1540 attributes. This is also needed, because the root
1541 node will at first have no permissions */
1542 if (err == -EACCES && !refreshed) {
1543 err = fuse_perm_getattr(inode, mask);
1544 if (!err)
1545 err = generic_permission(&nop_mnt_idmap,
1546 inode, mask);
1547 }
1548
1549 /* Note: the opposite of the above test does not
1550 exist. So if permissions are revoked this won't be
1551 noticed immediately, only after the attribute
1552 timeout has expired */
1553 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1554 err = fuse_access(inode, mask);
1555 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1556 if (!(inode->i_mode & S_IXUGO)) {
1557 if (refreshed)
1558 return -EACCES;
1559
1560 err = fuse_perm_getattr(inode, mask);
1561 if (!err && !(inode->i_mode & S_IXUGO))
1562 return -EACCES;
1563 }
1564 }
1565 return err;
1566}
1567
1568static int fuse_readlink_page(struct inode *inode, struct page *page)
1569{
1570 struct fuse_mount *fm = get_fuse_mount(inode);
1571 struct fuse_page_desc desc = { .length = PAGE_SIZE - 1 };
1572 struct fuse_args_pages ap = {
1573 .num_pages = 1,
1574 .pages = &page,
1575 .descs = &desc,
1576 };
1577 char *link;
1578 ssize_t res;
1579
1580 ap.args.opcode = FUSE_READLINK;
1581 ap.args.nodeid = get_node_id(inode);
1582 ap.args.out_pages = true;
1583 ap.args.out_argvar = true;
1584 ap.args.page_zeroing = true;
1585 ap.args.out_numargs = 1;
1586 ap.args.out_args[0].size = desc.length;
1587 res = fuse_simple_request(fm, &ap.args);
1588
1589 fuse_invalidate_atime(inode);
1590
1591 if (res < 0)
1592 return res;
1593
1594 if (WARN_ON(res >= PAGE_SIZE))
1595 return -EIO;
1596
1597 link = page_address(page);
1598 link[res] = '\0';
1599
1600 return 0;
1601}
1602
1603static const char *fuse_get_link(struct dentry *dentry, struct inode *inode,
1604 struct delayed_call *callback)
1605{
1606 struct fuse_conn *fc = get_fuse_conn(inode);
1607 struct page *page;
1608 int err;
1609
1610 err = -EIO;
1611 if (fuse_is_bad(inode))
1612 goto out_err;
1613
1614 if (fc->cache_symlinks)
1615 return page_get_link(dentry, inode, callback);
1616
1617 err = -ECHILD;
1618 if (!dentry)
1619 goto out_err;
1620
1621 page = alloc_page(GFP_KERNEL);
1622 err = -ENOMEM;
1623 if (!page)
1624 goto out_err;
1625
1626 err = fuse_readlink_page(inode, page);
1627 if (err) {
1628 __free_page(page);
1629 goto out_err;
1630 }
1631
1632 set_delayed_call(callback, page_put_link, page);
1633
1634 return page_address(page);
1635
1636out_err:
1637 return ERR_PTR(err);
1638}
1639
1640static int fuse_dir_open(struct inode *inode, struct file *file)
1641{
1642 struct fuse_mount *fm = get_fuse_mount(inode);
1643 int err;
1644
1645 if (fuse_is_bad(inode))
1646 return -EIO;
1647
1648 err = generic_file_open(inode, file);
1649 if (err)
1650 return err;
1651
1652 err = fuse_do_open(fm, get_node_id(inode), file, true);
1653 if (!err) {
1654 struct fuse_file *ff = file->private_data;
1655
1656 /*
1657 * Keep handling FOPEN_STREAM and FOPEN_NONSEEKABLE for
1658 * directories for backward compatibility, though it's unlikely
1659 * to be useful.
1660 */
1661 if (ff->open_flags & (FOPEN_STREAM | FOPEN_NONSEEKABLE))
1662 nonseekable_open(inode, file);
1663 }
1664
1665 return err;
1666}
1667
1668static int fuse_dir_release(struct inode *inode, struct file *file)
1669{
1670 fuse_release_common(file, true);
1671
1672 return 0;
1673}
1674
1675static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1676 int datasync)
1677{
1678 struct inode *inode = file->f_mapping->host;
1679 struct fuse_conn *fc = get_fuse_conn(inode);
1680 int err;
1681
1682 if (fuse_is_bad(inode))
1683 return -EIO;
1684
1685 if (fc->no_fsyncdir)
1686 return 0;
1687
1688 inode_lock(inode);
1689 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNCDIR);
1690 if (err == -ENOSYS) {
1691 fc->no_fsyncdir = 1;
1692 err = 0;
1693 }
1694 inode_unlock(inode);
1695
1696 return err;
1697}
1698
1699static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1700 unsigned long arg)
1701{
1702 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1703
1704 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1705 if (fc->minor < 18)
1706 return -ENOTTY;
1707
1708 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1709}
1710
1711static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1712 unsigned long arg)
1713{
1714 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1715
1716 if (fc->minor < 18)
1717 return -ENOTTY;
1718
1719 return fuse_ioctl_common(file, cmd, arg,
1720 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1721}
1722
1723static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1724{
1725 /* Always update if mtime is explicitly set */
1726 if (ivalid & ATTR_MTIME_SET)
1727 return true;
1728
1729 /* Or if kernel i_mtime is the official one */
1730 if (trust_local_mtime)
1731 return true;
1732
1733 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1734 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1735 return false;
1736
1737 /* In all other cases update */
1738 return true;
1739}
1740
1741static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
1742 struct fuse_setattr_in *arg, bool trust_local_cmtime)
1743{
1744 unsigned ivalid = iattr->ia_valid;
1745
1746 if (ivalid & ATTR_MODE)
1747 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1748 if (ivalid & ATTR_UID)
1749 arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
1750 if (ivalid & ATTR_GID)
1751 arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
1752 if (ivalid & ATTR_SIZE)
1753 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1754 if (ivalid & ATTR_ATIME) {
1755 arg->valid |= FATTR_ATIME;
1756 arg->atime = iattr->ia_atime.tv_sec;
1757 arg->atimensec = iattr->ia_atime.tv_nsec;
1758 if (!(ivalid & ATTR_ATIME_SET))
1759 arg->valid |= FATTR_ATIME_NOW;
1760 }
1761 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1762 arg->valid |= FATTR_MTIME;
1763 arg->mtime = iattr->ia_mtime.tv_sec;
1764 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1765 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1766 arg->valid |= FATTR_MTIME_NOW;
1767 }
1768 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1769 arg->valid |= FATTR_CTIME;
1770 arg->ctime = iattr->ia_ctime.tv_sec;
1771 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1772 }
1773}
1774
1775/*
1776 * Prevent concurrent writepages on inode
1777 *
1778 * This is done by adding a negative bias to the inode write counter
1779 * and waiting for all pending writes to finish.
1780 */
1781void fuse_set_nowrite(struct inode *inode)
1782{
1783 struct fuse_inode *fi = get_fuse_inode(inode);
1784
1785 BUG_ON(!inode_is_locked(inode));
1786
1787 spin_lock(&fi->lock);
1788 BUG_ON(fi->writectr < 0);
1789 fi->writectr += FUSE_NOWRITE;
1790 spin_unlock(&fi->lock);
1791 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1792}
1793
1794/*
1795 * Allow writepages on inode
1796 *
1797 * Remove the bias from the writecounter and send any queued
1798 * writepages.
1799 */
1800static void __fuse_release_nowrite(struct inode *inode)
1801{
1802 struct fuse_inode *fi = get_fuse_inode(inode);
1803
1804 BUG_ON(fi->writectr != FUSE_NOWRITE);
1805 fi->writectr = 0;
1806 fuse_flush_writepages(inode);
1807}
1808
1809void fuse_release_nowrite(struct inode *inode)
1810{
1811 struct fuse_inode *fi = get_fuse_inode(inode);
1812
1813 spin_lock(&fi->lock);
1814 __fuse_release_nowrite(inode);
1815 spin_unlock(&fi->lock);
1816}
1817
1818static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1819 struct inode *inode,
1820 struct fuse_setattr_in *inarg_p,
1821 struct fuse_attr_out *outarg_p)
1822{
1823 args->opcode = FUSE_SETATTR;
1824 args->nodeid = get_node_id(inode);
1825 args->in_numargs = 1;
1826 args->in_args[0].size = sizeof(*inarg_p);
1827 args->in_args[0].value = inarg_p;
1828 args->out_numargs = 1;
1829 args->out_args[0].size = sizeof(*outarg_p);
1830 args->out_args[0].value = outarg_p;
1831}
1832
1833/*
1834 * Flush inode->i_mtime to the server
1835 */
1836int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1837{
1838 struct fuse_mount *fm = get_fuse_mount(inode);
1839 FUSE_ARGS(args);
1840 struct fuse_setattr_in inarg;
1841 struct fuse_attr_out outarg;
1842
1843 memset(&inarg, 0, sizeof(inarg));
1844 memset(&outarg, 0, sizeof(outarg));
1845
1846 inarg.valid = FATTR_MTIME;
1847 inarg.mtime = inode_get_mtime_sec(inode);
1848 inarg.mtimensec = inode_get_mtime_nsec(inode);
1849 if (fm->fc->minor >= 23) {
1850 inarg.valid |= FATTR_CTIME;
1851 inarg.ctime = inode_get_ctime_sec(inode);
1852 inarg.ctimensec = inode_get_ctime_nsec(inode);
1853 }
1854 if (ff) {
1855 inarg.valid |= FATTR_FH;
1856 inarg.fh = ff->fh;
1857 }
1858 fuse_setattr_fill(fm->fc, &args, inode, &inarg, &outarg);
1859
1860 return fuse_simple_request(fm, &args);
1861}
1862
1863/*
1864 * Set attributes, and at the same time refresh them.
1865 *
1866 * Truncation is slightly complicated, because the 'truncate' request
1867 * may fail, in which case we don't want to touch the mapping.
1868 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1869 * and the actual truncation by hand.
1870 */
1871int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1872 struct file *file)
1873{
1874 struct inode *inode = d_inode(dentry);
1875 struct fuse_mount *fm = get_fuse_mount(inode);
1876 struct fuse_conn *fc = fm->fc;
1877 struct fuse_inode *fi = get_fuse_inode(inode);
1878 struct address_space *mapping = inode->i_mapping;
1879 FUSE_ARGS(args);
1880 struct fuse_setattr_in inarg;
1881 struct fuse_attr_out outarg;
1882 bool is_truncate = false;
1883 bool is_wb = fc->writeback_cache && S_ISREG(inode->i_mode);
1884 loff_t oldsize;
1885 int err;
1886 bool trust_local_cmtime = is_wb;
1887 bool fault_blocked = false;
1888
1889 if (!fc->default_permissions)
1890 attr->ia_valid |= ATTR_FORCE;
1891
1892 err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
1893 if (err)
1894 return err;
1895
1896 if (attr->ia_valid & ATTR_SIZE) {
1897 if (WARN_ON(!S_ISREG(inode->i_mode)))
1898 return -EIO;
1899 is_truncate = true;
1900 }
1901
1902 if (FUSE_IS_DAX(inode) && is_truncate) {
1903 filemap_invalidate_lock(mapping);
1904 fault_blocked = true;
1905 err = fuse_dax_break_layouts(inode, 0, 0);
1906 if (err) {
1907 filemap_invalidate_unlock(mapping);
1908 return err;
1909 }
1910 }
1911
1912 if (attr->ia_valid & ATTR_OPEN) {
1913 /* This is coming from open(..., ... | O_TRUNC); */
1914 WARN_ON(!(attr->ia_valid & ATTR_SIZE));
1915 WARN_ON(attr->ia_size != 0);
1916 if (fc->atomic_o_trunc) {
1917 /*
1918 * No need to send request to userspace, since actual
1919 * truncation has already been done by OPEN. But still
1920 * need to truncate page cache.
1921 */
1922 i_size_write(inode, 0);
1923 truncate_pagecache(inode, 0);
1924 goto out;
1925 }
1926 file = NULL;
1927 }
1928
1929 /* Flush dirty data/metadata before non-truncate SETATTR */
1930 if (is_wb &&
1931 attr->ia_valid &
1932 (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_MTIME_SET |
1933 ATTR_TIMES_SET)) {
1934 err = write_inode_now(inode, true);
1935 if (err)
1936 return err;
1937
1938 fuse_set_nowrite(inode);
1939 fuse_release_nowrite(inode);
1940 }
1941
1942 if (is_truncate) {
1943 fuse_set_nowrite(inode);
1944 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1945 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1946 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1947 }
1948
1949 memset(&inarg, 0, sizeof(inarg));
1950 memset(&outarg, 0, sizeof(outarg));
1951 iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
1952 if (file) {
1953 struct fuse_file *ff = file->private_data;
1954 inarg.valid |= FATTR_FH;
1955 inarg.fh = ff->fh;
1956 }
1957
1958 /* Kill suid/sgid for non-directory chown unconditionally */
1959 if (fc->handle_killpriv_v2 && !S_ISDIR(inode->i_mode) &&
1960 attr->ia_valid & (ATTR_UID | ATTR_GID))
1961 inarg.valid |= FATTR_KILL_SUIDGID;
1962
1963 if (attr->ia_valid & ATTR_SIZE) {
1964 /* For mandatory locking in truncate */
1965 inarg.valid |= FATTR_LOCKOWNER;
1966 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1967
1968 /* Kill suid/sgid for truncate only if no CAP_FSETID */
1969 if (fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1970 inarg.valid |= FATTR_KILL_SUIDGID;
1971 }
1972 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1973 err = fuse_simple_request(fm, &args);
1974 if (err) {
1975 if (err == -EINTR)
1976 fuse_invalidate_attr(inode);
1977 goto error;
1978 }
1979
1980 if (fuse_invalid_attr(&outarg.attr) ||
1981 inode_wrong_type(inode, outarg.attr.mode)) {
1982 fuse_make_bad(inode);
1983 err = -EIO;
1984 goto error;
1985 }
1986
1987 spin_lock(&fi->lock);
1988 /* the kernel maintains i_mtime locally */
1989 if (trust_local_cmtime) {
1990 if (attr->ia_valid & ATTR_MTIME)
1991 inode_set_mtime_to_ts(inode, attr->ia_mtime);
1992 if (attr->ia_valid & ATTR_CTIME)
1993 inode_set_ctime_to_ts(inode, attr->ia_ctime);
1994 /* FIXME: clear I_DIRTY_SYNC? */
1995 }
1996
1997 fuse_change_attributes_common(inode, &outarg.attr, NULL,
1998 ATTR_TIMEOUT(&outarg),
1999 fuse_get_cache_mask(inode));
2000 oldsize = inode->i_size;
2001 /* see the comment in fuse_change_attributes() */
2002 if (!is_wb || is_truncate)
2003 i_size_write(inode, outarg.attr.size);
2004
2005 if (is_truncate) {
2006 /* NOTE: this may release/reacquire fi->lock */
2007 __fuse_release_nowrite(inode);
2008 }
2009 spin_unlock(&fi->lock);
2010
2011 /*
2012 * Only call invalidate_inode_pages2() after removing
2013 * FUSE_NOWRITE, otherwise fuse_launder_folio() would deadlock.
2014 */
2015 if ((is_truncate || !is_wb) &&
2016 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
2017 truncate_pagecache(inode, outarg.attr.size);
2018 invalidate_inode_pages2(mapping);
2019 }
2020
2021 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2022out:
2023 if (fault_blocked)
2024 filemap_invalidate_unlock(mapping);
2025
2026 return 0;
2027
2028error:
2029 if (is_truncate)
2030 fuse_release_nowrite(inode);
2031
2032 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2033
2034 if (fault_blocked)
2035 filemap_invalidate_unlock(mapping);
2036 return err;
2037}
2038
2039static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
2040 struct iattr *attr)
2041{
2042 struct inode *inode = d_inode(entry);
2043 struct fuse_conn *fc = get_fuse_conn(inode);
2044 struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
2045 int ret;
2046
2047 if (fuse_is_bad(inode))
2048 return -EIO;
2049
2050 if (!fuse_allow_current_process(get_fuse_conn(inode)))
2051 return -EACCES;
2052
2053 if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
2054 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
2055 ATTR_MODE);
2056
2057 /*
2058 * The only sane way to reliably kill suid/sgid is to do it in
2059 * the userspace filesystem
2060 *
2061 * This should be done on write(), truncate() and chown().
2062 */
2063 if (!fc->handle_killpriv && !fc->handle_killpriv_v2) {
2064 /*
2065 * ia_mode calculation may have used stale i_mode.
2066 * Refresh and recalculate.
2067 */
2068 ret = fuse_do_getattr(inode, NULL, file);
2069 if (ret)
2070 return ret;
2071
2072 attr->ia_mode = inode->i_mode;
2073 if (inode->i_mode & S_ISUID) {
2074 attr->ia_valid |= ATTR_MODE;
2075 attr->ia_mode &= ~S_ISUID;
2076 }
2077 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
2078 attr->ia_valid |= ATTR_MODE;
2079 attr->ia_mode &= ~S_ISGID;
2080 }
2081 }
2082 }
2083 if (!attr->ia_valid)
2084 return 0;
2085
2086 ret = fuse_do_setattr(entry, attr, file);
2087 if (!ret) {
2088 /*
2089 * If filesystem supports acls it may have updated acl xattrs in
2090 * the filesystem, so forget cached acls for the inode.
2091 */
2092 if (fc->posix_acl)
2093 forget_all_cached_acls(inode);
2094
2095 /* Directory mode changed, may need to revalidate access */
2096 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
2097 fuse_invalidate_entry_cache(entry);
2098 }
2099 return ret;
2100}
2101
2102static int fuse_getattr(struct mnt_idmap *idmap,
2103 const struct path *path, struct kstat *stat,
2104 u32 request_mask, unsigned int flags)
2105{
2106 struct inode *inode = d_inode(path->dentry);
2107 struct fuse_conn *fc = get_fuse_conn(inode);
2108
2109 if (fuse_is_bad(inode))
2110 return -EIO;
2111
2112 if (!fuse_allow_current_process(fc)) {
2113 if (!request_mask) {
2114 /*
2115 * If user explicitly requested *nothing* then don't
2116 * error out, but return st_dev only.
2117 */
2118 stat->result_mask = 0;
2119 stat->dev = inode->i_sb->s_dev;
2120 return 0;
2121 }
2122 return -EACCES;
2123 }
2124
2125 return fuse_update_get_attr(inode, NULL, stat, request_mask, flags);
2126}
2127
2128static const struct inode_operations fuse_dir_inode_operations = {
2129 .lookup = fuse_lookup,
2130 .mkdir = fuse_mkdir,
2131 .symlink = fuse_symlink,
2132 .unlink = fuse_unlink,
2133 .rmdir = fuse_rmdir,
2134 .rename = fuse_rename2,
2135 .link = fuse_link,
2136 .setattr = fuse_setattr,
2137 .create = fuse_create,
2138 .atomic_open = fuse_atomic_open,
2139 .tmpfile = fuse_tmpfile,
2140 .mknod = fuse_mknod,
2141 .permission = fuse_permission,
2142 .getattr = fuse_getattr,
2143 .listxattr = fuse_listxattr,
2144 .get_inode_acl = fuse_get_inode_acl,
2145 .get_acl = fuse_get_acl,
2146 .set_acl = fuse_set_acl,
2147 .fileattr_get = fuse_fileattr_get,
2148 .fileattr_set = fuse_fileattr_set,
2149};
2150
2151static const struct file_operations fuse_dir_operations = {
2152 .llseek = generic_file_llseek,
2153 .read = generic_read_dir,
2154 .iterate_shared = fuse_readdir,
2155 .open = fuse_dir_open,
2156 .release = fuse_dir_release,
2157 .fsync = fuse_dir_fsync,
2158 .unlocked_ioctl = fuse_dir_ioctl,
2159 .compat_ioctl = fuse_dir_compat_ioctl,
2160};
2161
2162static const struct inode_operations fuse_common_inode_operations = {
2163 .setattr = fuse_setattr,
2164 .permission = fuse_permission,
2165 .getattr = fuse_getattr,
2166 .listxattr = fuse_listxattr,
2167 .get_inode_acl = fuse_get_inode_acl,
2168 .get_acl = fuse_get_acl,
2169 .set_acl = fuse_set_acl,
2170 .fileattr_get = fuse_fileattr_get,
2171 .fileattr_set = fuse_fileattr_set,
2172};
2173
2174static const struct inode_operations fuse_symlink_inode_operations = {
2175 .setattr = fuse_setattr,
2176 .get_link = fuse_get_link,
2177 .getattr = fuse_getattr,
2178 .listxattr = fuse_listxattr,
2179};
2180
2181void fuse_init_common(struct inode *inode)
2182{
2183 inode->i_op = &fuse_common_inode_operations;
2184}
2185
2186void fuse_init_dir(struct inode *inode)
2187{
2188 struct fuse_inode *fi = get_fuse_inode(inode);
2189
2190 inode->i_op = &fuse_dir_inode_operations;
2191 inode->i_fop = &fuse_dir_operations;
2192
2193 spin_lock_init(&fi->rdc.lock);
2194 fi->rdc.cached = false;
2195 fi->rdc.size = 0;
2196 fi->rdc.pos = 0;
2197 fi->rdc.version = 0;
2198}
2199
2200static int fuse_symlink_read_folio(struct file *null, struct folio *folio)
2201{
2202 int err = fuse_readlink_page(folio->mapping->host, &folio->page);
2203
2204 if (!err)
2205 folio_mark_uptodate(folio);
2206
2207 folio_unlock(folio);
2208
2209 return err;
2210}
2211
2212static const struct address_space_operations fuse_symlink_aops = {
2213 .read_folio = fuse_symlink_read_folio,
2214};
2215
2216void fuse_init_symlink(struct inode *inode)
2217{
2218 inode->i_op = &fuse_symlink_inode_operations;
2219 inode->i_data.a_ops = &fuse_symlink_aops;
2220 inode_nohighmem(inode);
2221}