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[mirror_ubuntu-zesty-kernel.git] / fs / fuse / dir.c
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 #include <linux/xattr.h>
17 #include <linux/posix_acl.h>
18
19 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
20 {
21 struct fuse_conn *fc = get_fuse_conn(dir);
22 struct fuse_inode *fi = get_fuse_inode(dir);
23
24 if (!fc->do_readdirplus)
25 return false;
26 if (!fc->readdirplus_auto)
27 return true;
28 if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
29 return true;
30 if (ctx->pos == 0)
31 return true;
32 return false;
33 }
34
35 static void fuse_advise_use_readdirplus(struct inode *dir)
36 {
37 struct fuse_inode *fi = get_fuse_inode(dir);
38
39 set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
40 }
41
42 union fuse_dentry {
43 u64 time;
44 struct rcu_head rcu;
45 };
46
47 static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
48 {
49 ((union fuse_dentry *) entry->d_fsdata)->time = time;
50 }
51
52 static inline u64 fuse_dentry_time(struct dentry *entry)
53 {
54 return ((union fuse_dentry *) entry->d_fsdata)->time;
55 }
56
57 /*
58 * FUSE caches dentries and attributes with separate timeout. The
59 * time in jiffies until the dentry/attributes are valid is stored in
60 * dentry->d_fsdata and fuse_inode->i_time respectively.
61 */
62
63 /*
64 * Calculate the time in jiffies until a dentry/attributes are valid
65 */
66 static u64 time_to_jiffies(u64 sec, u32 nsec)
67 {
68 if (sec || nsec) {
69 struct timespec64 ts = {
70 sec,
71 min_t(u32, nsec, NSEC_PER_SEC - 1)
72 };
73
74 return get_jiffies_64() + timespec64_to_jiffies(&ts);
75 } else
76 return 0;
77 }
78
79 /*
80 * Set dentry and possibly attribute timeouts from the lookup/mk*
81 * replies
82 */
83 static void fuse_change_entry_timeout(struct dentry *entry,
84 struct fuse_entry_out *o)
85 {
86 fuse_dentry_settime(entry,
87 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
88 }
89
90 static u64 attr_timeout(struct fuse_attr_out *o)
91 {
92 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
93 }
94
95 static u64 entry_attr_timeout(struct fuse_entry_out *o)
96 {
97 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
98 }
99
100 /*
101 * Mark the attributes as stale, so that at the next call to
102 * ->getattr() they will be fetched from userspace
103 */
104 void fuse_invalidate_attr(struct inode *inode)
105 {
106 get_fuse_inode(inode)->i_time = 0;
107 }
108
109 /**
110 * Mark the attributes as stale due to an atime change. Avoid the invalidate if
111 * atime is not used.
112 */
113 void fuse_invalidate_atime(struct inode *inode)
114 {
115 if (!IS_RDONLY(inode))
116 fuse_invalidate_attr(inode);
117 }
118
119 /*
120 * Just mark the entry as stale, so that a next attempt to look it up
121 * will result in a new lookup call to userspace
122 *
123 * This is called when a dentry is about to become negative and the
124 * timeout is unknown (unlink, rmdir, rename and in some cases
125 * lookup)
126 */
127 void fuse_invalidate_entry_cache(struct dentry *entry)
128 {
129 fuse_dentry_settime(entry, 0);
130 }
131
132 /*
133 * Same as fuse_invalidate_entry_cache(), but also try to remove the
134 * dentry from the hash
135 */
136 static void fuse_invalidate_entry(struct dentry *entry)
137 {
138 d_invalidate(entry);
139 fuse_invalidate_entry_cache(entry);
140 }
141
142 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
143 u64 nodeid, const struct qstr *name,
144 struct fuse_entry_out *outarg)
145 {
146 memset(outarg, 0, sizeof(struct fuse_entry_out));
147 args->in.h.opcode = FUSE_LOOKUP;
148 args->in.h.nodeid = nodeid;
149 args->in.numargs = 1;
150 args->in.args[0].size = name->len + 1;
151 args->in.args[0].value = name->name;
152 args->out.numargs = 1;
153 args->out.args[0].size = sizeof(struct fuse_entry_out);
154 args->out.args[0].value = outarg;
155 }
156
157 u64 fuse_get_attr_version(struct fuse_conn *fc)
158 {
159 u64 curr_version;
160
161 /*
162 * The spin lock isn't actually needed on 64bit archs, but we
163 * don't yet care too much about such optimizations.
164 */
165 spin_lock(&fc->lock);
166 curr_version = fc->attr_version;
167 spin_unlock(&fc->lock);
168
169 return curr_version;
170 }
171
172 /*
173 * Check whether the dentry is still valid
174 *
175 * If the entry validity timeout has expired and the dentry is
176 * positive, try to redo the lookup. If the lookup results in a
177 * different inode, then let the VFS invalidate the dentry and redo
178 * the lookup once more. If the lookup results in the same inode,
179 * then refresh the attributes, timeouts and mark the dentry valid.
180 */
181 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
182 {
183 struct inode *inode;
184 struct dentry *parent;
185 struct fuse_conn *fc;
186 struct fuse_inode *fi;
187 int ret;
188
189 inode = d_inode_rcu(entry);
190 if (inode && is_bad_inode(inode))
191 goto invalid;
192 else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
193 (flags & LOOKUP_REVAL)) {
194 struct fuse_entry_out outarg;
195 FUSE_ARGS(args);
196 struct fuse_forget_link *forget;
197 u64 attr_version;
198
199 /* For negative dentries, always do a fresh lookup */
200 if (!inode)
201 goto invalid;
202
203 ret = -ECHILD;
204 if (flags & LOOKUP_RCU)
205 goto out;
206
207 fc = get_fuse_conn(inode);
208
209 forget = fuse_alloc_forget();
210 ret = -ENOMEM;
211 if (!forget)
212 goto out;
213
214 attr_version = fuse_get_attr_version(fc);
215
216 parent = dget_parent(entry);
217 fuse_lookup_init(fc, &args, get_node_id(d_inode(parent)),
218 &entry->d_name, &outarg);
219 ret = fuse_simple_request(fc, &args);
220 dput(parent);
221 /* Zero nodeid is same as -ENOENT */
222 if (!ret && !outarg.nodeid)
223 ret = -ENOENT;
224 if (!ret) {
225 fi = get_fuse_inode(inode);
226 if (outarg.nodeid != get_node_id(inode)) {
227 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
228 goto invalid;
229 }
230 spin_lock(&fc->lock);
231 fi->nlookup++;
232 spin_unlock(&fc->lock);
233 }
234 kfree(forget);
235 if (ret == -ENOMEM)
236 goto out;
237 if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
238 goto invalid;
239
240 forget_all_cached_acls(inode);
241 fuse_change_attributes(inode, &outarg.attr,
242 entry_attr_timeout(&outarg),
243 attr_version);
244 fuse_change_entry_timeout(entry, &outarg);
245 } else if (inode) {
246 fi = get_fuse_inode(inode);
247 if (flags & LOOKUP_RCU) {
248 if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
249 return -ECHILD;
250 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
251 parent = dget_parent(entry);
252 fuse_advise_use_readdirplus(d_inode(parent));
253 dput(parent);
254 }
255 }
256 ret = 1;
257 out:
258 return ret;
259
260 invalid:
261 ret = 0;
262 goto out;
263 }
264
265 static int invalid_nodeid(u64 nodeid)
266 {
267 return !nodeid || nodeid == FUSE_ROOT_ID;
268 }
269
270 static int fuse_dentry_init(struct dentry *dentry)
271 {
272 dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry), GFP_KERNEL);
273
274 return dentry->d_fsdata ? 0 : -ENOMEM;
275 }
276 static void fuse_dentry_release(struct dentry *dentry)
277 {
278 union fuse_dentry *fd = dentry->d_fsdata;
279
280 kfree_rcu(fd, rcu);
281 }
282
283 const struct dentry_operations fuse_dentry_operations = {
284 .d_revalidate = fuse_dentry_revalidate,
285 .d_init = fuse_dentry_init,
286 .d_release = fuse_dentry_release,
287 };
288
289 const struct dentry_operations fuse_root_dentry_operations = {
290 .d_init = fuse_dentry_init,
291 .d_release = fuse_dentry_release,
292 };
293
294 int fuse_valid_type(int m)
295 {
296 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
297 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
298 }
299
300 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
301 struct fuse_entry_out *outarg, struct inode **inode)
302 {
303 struct fuse_conn *fc = get_fuse_conn_super(sb);
304 FUSE_ARGS(args);
305 struct fuse_forget_link *forget;
306 u64 attr_version;
307 int err;
308
309 *inode = NULL;
310 err = -ENAMETOOLONG;
311 if (name->len > FUSE_NAME_MAX)
312 goto out;
313
314
315 forget = fuse_alloc_forget();
316 err = -ENOMEM;
317 if (!forget)
318 goto out;
319
320 attr_version = fuse_get_attr_version(fc);
321
322 fuse_lookup_init(fc, &args, nodeid, name, outarg);
323 err = fuse_simple_request(fc, &args);
324 /* Zero nodeid is same as -ENOENT, but with valid timeout */
325 if (err || !outarg->nodeid)
326 goto out_put_forget;
327
328 err = -EIO;
329 if (!outarg->nodeid)
330 goto out_put_forget;
331 if (!fuse_valid_type(outarg->attr.mode))
332 goto out_put_forget;
333
334 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
335 &outarg->attr, entry_attr_timeout(outarg),
336 attr_version);
337 err = -ENOMEM;
338 if (!*inode) {
339 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
340 goto out;
341 }
342 err = 0;
343
344 out_put_forget:
345 kfree(forget);
346 out:
347 return err;
348 }
349
350 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
351 unsigned int flags)
352 {
353 int err;
354 struct fuse_entry_out outarg;
355 struct inode *inode;
356 struct dentry *newent;
357 bool outarg_valid = true;
358
359 fuse_lock_inode(dir);
360 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
361 &outarg, &inode);
362 fuse_unlock_inode(dir);
363 if (err == -ENOENT) {
364 outarg_valid = false;
365 err = 0;
366 }
367 if (err)
368 goto out_err;
369
370 err = -EIO;
371 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
372 goto out_iput;
373
374 newent = d_splice_alias(inode, entry);
375 err = PTR_ERR(newent);
376 if (IS_ERR(newent))
377 goto out_err;
378
379 entry = newent ? newent : entry;
380 if (outarg_valid)
381 fuse_change_entry_timeout(entry, &outarg);
382 else
383 fuse_invalidate_entry_cache(entry);
384
385 fuse_advise_use_readdirplus(dir);
386 return newent;
387
388 out_iput:
389 iput(inode);
390 out_err:
391 return ERR_PTR(err);
392 }
393
394 /*
395 * Atomic create+open operation
396 *
397 * If the filesystem doesn't support this, then fall back to separate
398 * 'mknod' + 'open' requests.
399 */
400 static int fuse_create_open(struct inode *dir, struct dentry *entry,
401 struct file *file, unsigned flags,
402 umode_t mode, int *opened)
403 {
404 int err;
405 struct inode *inode;
406 struct fuse_conn *fc = get_fuse_conn(dir);
407 FUSE_ARGS(args);
408 struct fuse_forget_link *forget;
409 struct fuse_create_in inarg;
410 struct fuse_open_out outopen;
411 struct fuse_entry_out outentry;
412 struct fuse_file *ff;
413
414 /* Userspace expects S_IFREG in create mode */
415 BUG_ON((mode & S_IFMT) != S_IFREG);
416
417 forget = fuse_alloc_forget();
418 err = -ENOMEM;
419 if (!forget)
420 goto out_err;
421
422 err = -ENOMEM;
423 ff = fuse_file_alloc(fc);
424 if (!ff)
425 goto out_put_forget_req;
426
427 if (!fc->dont_mask)
428 mode &= ~current_umask();
429
430 flags &= ~O_NOCTTY;
431 memset(&inarg, 0, sizeof(inarg));
432 memset(&outentry, 0, sizeof(outentry));
433 inarg.flags = flags;
434 inarg.mode = mode;
435 inarg.umask = current_umask();
436 args.in.h.opcode = FUSE_CREATE;
437 args.in.h.nodeid = get_node_id(dir);
438 args.in.numargs = 2;
439 args.in.args[0].size = sizeof(inarg);
440 args.in.args[0].value = &inarg;
441 args.in.args[1].size = entry->d_name.len + 1;
442 args.in.args[1].value = entry->d_name.name;
443 args.out.numargs = 2;
444 args.out.args[0].size = sizeof(outentry);
445 args.out.args[0].value = &outentry;
446 args.out.args[1].size = sizeof(outopen);
447 args.out.args[1].value = &outopen;
448 err = fuse_simple_request(fc, &args);
449 if (err)
450 goto out_free_ff;
451
452 err = -EIO;
453 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
454 goto out_free_ff;
455
456 ff->fh = outopen.fh;
457 ff->nodeid = outentry.nodeid;
458 ff->open_flags = outopen.open_flags;
459 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
460 &outentry.attr, entry_attr_timeout(&outentry), 0);
461 if (!inode) {
462 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
463 fuse_sync_release(ff, flags);
464 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
465 err = -ENOMEM;
466 goto out_err;
467 }
468 kfree(forget);
469 d_instantiate(entry, inode);
470 fuse_change_entry_timeout(entry, &outentry);
471 fuse_invalidate_attr(dir);
472 err = finish_open(file, entry, generic_file_open, opened);
473 if (err) {
474 fuse_sync_release(ff, flags);
475 } else {
476 file->private_data = fuse_file_get(ff);
477 fuse_finish_open(inode, file);
478 }
479 return err;
480
481 out_free_ff:
482 fuse_file_free(ff);
483 out_put_forget_req:
484 kfree(forget);
485 out_err:
486 return err;
487 }
488
489 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);
490 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
491 struct file *file, unsigned flags,
492 umode_t mode, int *opened)
493 {
494 int err;
495 struct fuse_conn *fc = get_fuse_conn(dir);
496 struct dentry *res = NULL;
497
498 if (d_in_lookup(entry)) {
499 res = fuse_lookup(dir, entry, 0);
500 if (IS_ERR(res))
501 return PTR_ERR(res);
502
503 if (res)
504 entry = res;
505 }
506
507 if (!(flags & O_CREAT) || d_really_is_positive(entry))
508 goto no_open;
509
510 /* Only creates */
511 *opened |= FILE_CREATED;
512
513 if (fc->no_create)
514 goto mknod;
515
516 err = fuse_create_open(dir, entry, file, flags, mode, opened);
517 if (err == -ENOSYS) {
518 fc->no_create = 1;
519 goto mknod;
520 }
521 out_dput:
522 dput(res);
523 return err;
524
525 mknod:
526 err = fuse_mknod(dir, entry, mode, 0);
527 if (err)
528 goto out_dput;
529 no_open:
530 return finish_no_open(file, res);
531 }
532
533 /*
534 * Code shared between mknod, mkdir, symlink and link
535 */
536 static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
537 struct inode *dir, struct dentry *entry,
538 umode_t mode)
539 {
540 struct fuse_entry_out outarg;
541 struct inode *inode;
542 int err;
543 struct fuse_forget_link *forget;
544
545 forget = fuse_alloc_forget();
546 if (!forget)
547 return -ENOMEM;
548
549 memset(&outarg, 0, sizeof(outarg));
550 args->in.h.nodeid = get_node_id(dir);
551 args->out.numargs = 1;
552 args->out.args[0].size = sizeof(outarg);
553 args->out.args[0].value = &outarg;
554 err = fuse_simple_request(fc, args);
555 if (err)
556 goto out_put_forget_req;
557
558 err = -EIO;
559 if (invalid_nodeid(outarg.nodeid))
560 goto out_put_forget_req;
561
562 if ((outarg.attr.mode ^ mode) & S_IFMT)
563 goto out_put_forget_req;
564
565 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
566 &outarg.attr, entry_attr_timeout(&outarg), 0);
567 if (!inode) {
568 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
569 return -ENOMEM;
570 }
571 kfree(forget);
572
573 err = d_instantiate_no_diralias(entry, inode);
574 if (err)
575 return err;
576
577 fuse_change_entry_timeout(entry, &outarg);
578 fuse_invalidate_attr(dir);
579 return 0;
580
581 out_put_forget_req:
582 kfree(forget);
583 return err;
584 }
585
586 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
587 dev_t rdev)
588 {
589 struct fuse_mknod_in inarg;
590 struct fuse_conn *fc = get_fuse_conn(dir);
591 FUSE_ARGS(args);
592
593 if (!fc->dont_mask)
594 mode &= ~current_umask();
595
596 memset(&inarg, 0, sizeof(inarg));
597 inarg.mode = mode;
598 inarg.rdev = new_encode_dev(rdev);
599 inarg.umask = current_umask();
600 args.in.h.opcode = FUSE_MKNOD;
601 args.in.numargs = 2;
602 args.in.args[0].size = sizeof(inarg);
603 args.in.args[0].value = &inarg;
604 args.in.args[1].size = entry->d_name.len + 1;
605 args.in.args[1].value = entry->d_name.name;
606 return create_new_entry(fc, &args, dir, entry, mode);
607 }
608
609 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
610 bool excl)
611 {
612 return fuse_mknod(dir, entry, mode, 0);
613 }
614
615 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
616 {
617 struct fuse_mkdir_in inarg;
618 struct fuse_conn *fc = get_fuse_conn(dir);
619 FUSE_ARGS(args);
620
621 if (!fc->dont_mask)
622 mode &= ~current_umask();
623
624 memset(&inarg, 0, sizeof(inarg));
625 inarg.mode = mode;
626 inarg.umask = current_umask();
627 args.in.h.opcode = FUSE_MKDIR;
628 args.in.numargs = 2;
629 args.in.args[0].size = sizeof(inarg);
630 args.in.args[0].value = &inarg;
631 args.in.args[1].size = entry->d_name.len + 1;
632 args.in.args[1].value = entry->d_name.name;
633 return create_new_entry(fc, &args, dir, entry, S_IFDIR);
634 }
635
636 static int fuse_symlink(struct inode *dir, struct dentry *entry,
637 const char *link)
638 {
639 struct fuse_conn *fc = get_fuse_conn(dir);
640 unsigned len = strlen(link) + 1;
641 FUSE_ARGS(args);
642
643 args.in.h.opcode = FUSE_SYMLINK;
644 args.in.numargs = 2;
645 args.in.args[0].size = entry->d_name.len + 1;
646 args.in.args[0].value = entry->d_name.name;
647 args.in.args[1].size = len;
648 args.in.args[1].value = link;
649 return create_new_entry(fc, &args, dir, entry, S_IFLNK);
650 }
651
652 void fuse_update_ctime(struct inode *inode)
653 {
654 if (!IS_NOCMTIME(inode)) {
655 inode->i_ctime = current_time(inode);
656 mark_inode_dirty_sync(inode);
657 }
658 }
659
660 static int fuse_unlink(struct inode *dir, struct dentry *entry)
661 {
662 int err;
663 struct fuse_conn *fc = get_fuse_conn(dir);
664 FUSE_ARGS(args);
665
666 args.in.h.opcode = FUSE_UNLINK;
667 args.in.h.nodeid = get_node_id(dir);
668 args.in.numargs = 1;
669 args.in.args[0].size = entry->d_name.len + 1;
670 args.in.args[0].value = entry->d_name.name;
671 err = fuse_simple_request(fc, &args);
672 if (!err) {
673 struct inode *inode = d_inode(entry);
674 struct fuse_inode *fi = get_fuse_inode(inode);
675
676 spin_lock(&fc->lock);
677 fi->attr_version = ++fc->attr_version;
678 /*
679 * If i_nlink == 0 then unlink doesn't make sense, yet this can
680 * happen if userspace filesystem is careless. It would be
681 * difficult to enforce correct nlink usage so just ignore this
682 * condition here
683 */
684 if (inode->i_nlink > 0)
685 drop_nlink(inode);
686 spin_unlock(&fc->lock);
687 fuse_invalidate_attr(inode);
688 fuse_invalidate_attr(dir);
689 fuse_invalidate_entry_cache(entry);
690 fuse_update_ctime(inode);
691 } else if (err == -EINTR)
692 fuse_invalidate_entry(entry);
693 return err;
694 }
695
696 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
697 {
698 int err;
699 struct fuse_conn *fc = get_fuse_conn(dir);
700 FUSE_ARGS(args);
701
702 args.in.h.opcode = FUSE_RMDIR;
703 args.in.h.nodeid = get_node_id(dir);
704 args.in.numargs = 1;
705 args.in.args[0].size = entry->d_name.len + 1;
706 args.in.args[0].value = entry->d_name.name;
707 err = fuse_simple_request(fc, &args);
708 if (!err) {
709 clear_nlink(d_inode(entry));
710 fuse_invalidate_attr(dir);
711 fuse_invalidate_entry_cache(entry);
712 } else if (err == -EINTR)
713 fuse_invalidate_entry(entry);
714 return err;
715 }
716
717 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
718 struct inode *newdir, struct dentry *newent,
719 unsigned int flags, int opcode, size_t argsize)
720 {
721 int err;
722 struct fuse_rename2_in inarg;
723 struct fuse_conn *fc = get_fuse_conn(olddir);
724 FUSE_ARGS(args);
725
726 memset(&inarg, 0, argsize);
727 inarg.newdir = get_node_id(newdir);
728 inarg.flags = flags;
729 args.in.h.opcode = opcode;
730 args.in.h.nodeid = get_node_id(olddir);
731 args.in.numargs = 3;
732 args.in.args[0].size = argsize;
733 args.in.args[0].value = &inarg;
734 args.in.args[1].size = oldent->d_name.len + 1;
735 args.in.args[1].value = oldent->d_name.name;
736 args.in.args[2].size = newent->d_name.len + 1;
737 args.in.args[2].value = newent->d_name.name;
738 err = fuse_simple_request(fc, &args);
739 if (!err) {
740 /* ctime changes */
741 fuse_invalidate_attr(d_inode(oldent));
742 fuse_update_ctime(d_inode(oldent));
743
744 if (flags & RENAME_EXCHANGE) {
745 fuse_invalidate_attr(d_inode(newent));
746 fuse_update_ctime(d_inode(newent));
747 }
748
749 fuse_invalidate_attr(olddir);
750 if (olddir != newdir)
751 fuse_invalidate_attr(newdir);
752
753 /* newent will end up negative */
754 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) {
755 fuse_invalidate_attr(d_inode(newent));
756 fuse_invalidate_entry_cache(newent);
757 fuse_update_ctime(d_inode(newent));
758 }
759 } else if (err == -EINTR) {
760 /* If request was interrupted, DEITY only knows if the
761 rename actually took place. If the invalidation
762 fails (e.g. some process has CWD under the renamed
763 directory), then there can be inconsistency between
764 the dcache and the real filesystem. Tough luck. */
765 fuse_invalidate_entry(oldent);
766 if (d_really_is_positive(newent))
767 fuse_invalidate_entry(newent);
768 }
769
770 return err;
771 }
772
773 static int fuse_rename2(struct inode *olddir, struct dentry *oldent,
774 struct inode *newdir, struct dentry *newent,
775 unsigned int flags)
776 {
777 struct fuse_conn *fc = get_fuse_conn(olddir);
778 int err;
779
780 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
781 return -EINVAL;
782
783 if (flags) {
784 if (fc->no_rename2 || fc->minor < 23)
785 return -EINVAL;
786
787 err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
788 FUSE_RENAME2,
789 sizeof(struct fuse_rename2_in));
790 if (err == -ENOSYS) {
791 fc->no_rename2 = 1;
792 err = -EINVAL;
793 }
794 } else {
795 err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
796 FUSE_RENAME,
797 sizeof(struct fuse_rename_in));
798 }
799
800 return err;
801 }
802
803 static int fuse_link(struct dentry *entry, struct inode *newdir,
804 struct dentry *newent)
805 {
806 int err;
807 struct fuse_link_in inarg;
808 struct inode *inode = d_inode(entry);
809 struct fuse_conn *fc = get_fuse_conn(inode);
810 FUSE_ARGS(args);
811
812 memset(&inarg, 0, sizeof(inarg));
813 inarg.oldnodeid = get_node_id(inode);
814 args.in.h.opcode = FUSE_LINK;
815 args.in.numargs = 2;
816 args.in.args[0].size = sizeof(inarg);
817 args.in.args[0].value = &inarg;
818 args.in.args[1].size = newent->d_name.len + 1;
819 args.in.args[1].value = newent->d_name.name;
820 err = create_new_entry(fc, &args, newdir, newent, inode->i_mode);
821 /* Contrary to "normal" filesystems it can happen that link
822 makes two "logical" inodes point to the same "physical"
823 inode. We invalidate the attributes of the old one, so it
824 will reflect changes in the backing inode (link count,
825 etc.)
826 */
827 if (!err) {
828 struct fuse_inode *fi = get_fuse_inode(inode);
829
830 spin_lock(&fc->lock);
831 fi->attr_version = ++fc->attr_version;
832 inc_nlink(inode);
833 spin_unlock(&fc->lock);
834 fuse_invalidate_attr(inode);
835 fuse_update_ctime(inode);
836 } else if (err == -EINTR) {
837 fuse_invalidate_attr(inode);
838 }
839 return err;
840 }
841
842 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
843 struct kstat *stat)
844 {
845 unsigned int blkbits;
846 struct fuse_conn *fc = get_fuse_conn(inode);
847
848 /* see the comment in fuse_change_attributes() */
849 if (fc->writeback_cache && S_ISREG(inode->i_mode)) {
850 attr->size = i_size_read(inode);
851 attr->mtime = inode->i_mtime.tv_sec;
852 attr->mtimensec = inode->i_mtime.tv_nsec;
853 attr->ctime = inode->i_ctime.tv_sec;
854 attr->ctimensec = inode->i_ctime.tv_nsec;
855 }
856
857 stat->dev = inode->i_sb->s_dev;
858 stat->ino = attr->ino;
859 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
860 stat->nlink = attr->nlink;
861 stat->uid = make_kuid(fc->user_ns, attr->uid);
862 stat->gid = make_kgid(fc->user_ns, attr->gid);
863 stat->rdev = inode->i_rdev;
864 stat->atime.tv_sec = attr->atime;
865 stat->atime.tv_nsec = attr->atimensec;
866 stat->mtime.tv_sec = attr->mtime;
867 stat->mtime.tv_nsec = attr->mtimensec;
868 stat->ctime.tv_sec = attr->ctime;
869 stat->ctime.tv_nsec = attr->ctimensec;
870 stat->size = attr->size;
871 stat->blocks = attr->blocks;
872
873 if (attr->blksize != 0)
874 blkbits = ilog2(attr->blksize);
875 else
876 blkbits = inode->i_sb->s_blocksize_bits;
877
878 stat->blksize = 1 << blkbits;
879 }
880
881 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
882 struct file *file)
883 {
884 int err;
885 struct fuse_getattr_in inarg;
886 struct fuse_attr_out outarg;
887 struct fuse_conn *fc = get_fuse_conn(inode);
888 FUSE_ARGS(args);
889 u64 attr_version;
890
891 attr_version = fuse_get_attr_version(fc);
892
893 memset(&inarg, 0, sizeof(inarg));
894 memset(&outarg, 0, sizeof(outarg));
895 /* Directories have separate file-handle space */
896 if (file && S_ISREG(inode->i_mode)) {
897 struct fuse_file *ff = file->private_data;
898
899 inarg.getattr_flags |= FUSE_GETATTR_FH;
900 inarg.fh = ff->fh;
901 }
902 args.in.h.opcode = FUSE_GETATTR;
903 args.in.h.nodeid = get_node_id(inode);
904 args.in.numargs = 1;
905 args.in.args[0].size = sizeof(inarg);
906 args.in.args[0].value = &inarg;
907 args.out.numargs = 1;
908 args.out.args[0].size = sizeof(outarg);
909 args.out.args[0].value = &outarg;
910 err = fuse_simple_request(fc, &args);
911 if (!err) {
912 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
913 make_bad_inode(inode);
914 err = -EIO;
915 } else {
916 fuse_change_attributes(inode, &outarg.attr,
917 attr_timeout(&outarg),
918 attr_version);
919 if (stat)
920 fuse_fillattr(inode, &outarg.attr, stat);
921 }
922 }
923 return err;
924 }
925
926 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
927 struct file *file, bool *refreshed)
928 {
929 struct fuse_inode *fi = get_fuse_inode(inode);
930 int err;
931 bool r;
932
933 if (time_before64(fi->i_time, get_jiffies_64())) {
934 r = true;
935 forget_all_cached_acls(inode);
936 err = fuse_do_getattr(inode, stat, file);
937 } else {
938 r = false;
939 err = 0;
940 if (stat) {
941 generic_fillattr(inode, stat);
942 stat->mode = fi->orig_i_mode;
943 stat->ino = fi->orig_ino;
944 }
945 }
946
947 if (refreshed != NULL)
948 *refreshed = r;
949
950 return err;
951 }
952
953 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
954 u64 child_nodeid, struct qstr *name)
955 {
956 int err = -ENOTDIR;
957 struct inode *parent;
958 struct dentry *dir;
959 struct dentry *entry;
960
961 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
962 if (!parent)
963 return -ENOENT;
964
965 inode_lock(parent);
966 if (!S_ISDIR(parent->i_mode))
967 goto unlock;
968
969 err = -ENOENT;
970 dir = d_find_alias(parent);
971 if (!dir)
972 goto unlock;
973
974 name->hash = full_name_hash(dir, name->name, name->len);
975 entry = d_lookup(dir, name);
976 dput(dir);
977 if (!entry)
978 goto unlock;
979
980 fuse_invalidate_attr(parent);
981 fuse_invalidate_entry(entry);
982
983 if (child_nodeid != 0 && d_really_is_positive(entry)) {
984 inode_lock(d_inode(entry));
985 if (get_node_id(d_inode(entry)) != child_nodeid) {
986 err = -ENOENT;
987 goto badentry;
988 }
989 if (d_mountpoint(entry)) {
990 err = -EBUSY;
991 goto badentry;
992 }
993 if (d_is_dir(entry)) {
994 shrink_dcache_parent(entry);
995 if (!simple_empty(entry)) {
996 err = -ENOTEMPTY;
997 goto badentry;
998 }
999 d_inode(entry)->i_flags |= S_DEAD;
1000 }
1001 dont_mount(entry);
1002 clear_nlink(d_inode(entry));
1003 err = 0;
1004 badentry:
1005 inode_unlock(d_inode(entry));
1006 if (!err)
1007 d_delete(entry);
1008 } else {
1009 err = 0;
1010 }
1011 dput(entry);
1012
1013 unlock:
1014 inode_unlock(parent);
1015 iput(parent);
1016 return err;
1017 }
1018
1019 /*
1020 * Calling into a user-controlled filesystem gives the filesystem
1021 * daemon ptrace-like capabilities over the current process. This
1022 * means, that the filesystem daemon is able to record the exact
1023 * filesystem operations performed, and can also control the behavior
1024 * of the requester process in otherwise impossible ways. For example
1025 * it can delay the operation for arbitrary length of time allowing
1026 * DoS against the requester.
1027 *
1028 * For this reason only those processes can call into the filesystem,
1029 * for which the owner of the mount has ptrace privilege. This
1030 * excludes processes started by other users, suid or sgid processes.
1031 */
1032 int fuse_allow_current_process(struct fuse_conn *fc)
1033 {
1034 const struct cred *cred;
1035
1036 if (fc->allow_other)
1037 return 1;
1038
1039 cred = current_cred();
1040 if (uid_eq(cred->euid, fc->user_id) &&
1041 uid_eq(cred->suid, fc->user_id) &&
1042 uid_eq(cred->uid, fc->user_id) &&
1043 gid_eq(cred->egid, fc->group_id) &&
1044 gid_eq(cred->sgid, fc->group_id) &&
1045 gid_eq(cred->gid, fc->group_id))
1046 return 1;
1047
1048 return 0;
1049 }
1050
1051 static int fuse_access(struct inode *inode, int mask)
1052 {
1053 struct fuse_conn *fc = get_fuse_conn(inode);
1054 FUSE_ARGS(args);
1055 struct fuse_access_in inarg;
1056 int err;
1057
1058 BUG_ON(mask & MAY_NOT_BLOCK);
1059
1060 if (fc->no_access)
1061 return 0;
1062
1063 memset(&inarg, 0, sizeof(inarg));
1064 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1065 args.in.h.opcode = FUSE_ACCESS;
1066 args.in.h.nodeid = get_node_id(inode);
1067 args.in.numargs = 1;
1068 args.in.args[0].size = sizeof(inarg);
1069 args.in.args[0].value = &inarg;
1070 err = fuse_simple_request(fc, &args);
1071 if (err == -ENOSYS) {
1072 fc->no_access = 1;
1073 err = 0;
1074 }
1075 return err;
1076 }
1077
1078 static int fuse_perm_getattr(struct inode *inode, int mask)
1079 {
1080 if (mask & MAY_NOT_BLOCK)
1081 return -ECHILD;
1082
1083 forget_all_cached_acls(inode);
1084 return fuse_do_getattr(inode, NULL, NULL);
1085 }
1086
1087 /*
1088 * Check permission. The two basic access models of FUSE are:
1089 *
1090 * 1) Local access checking ('default_permissions' mount option) based
1091 * on file mode. This is the plain old disk filesystem permission
1092 * modell.
1093 *
1094 * 2) "Remote" access checking, where server is responsible for
1095 * checking permission in each inode operation. An exception to this
1096 * is if ->permission() was invoked from sys_access() in which case an
1097 * access request is sent. Execute permission is still checked
1098 * locally based on file mode.
1099 */
1100 static int fuse_permission(struct inode *inode, int mask)
1101 {
1102 struct fuse_conn *fc = get_fuse_conn(inode);
1103 bool refreshed = false;
1104 int err = 0;
1105
1106 if (!fuse_allow_current_process(fc))
1107 return -EACCES;
1108
1109 /*
1110 * If attributes are needed, refresh them before proceeding
1111 */
1112 if (fc->default_permissions ||
1113 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1114 struct fuse_inode *fi = get_fuse_inode(inode);
1115
1116 if (time_before64(fi->i_time, get_jiffies_64())) {
1117 refreshed = true;
1118
1119 err = fuse_perm_getattr(inode, mask);
1120 if (err)
1121 return err;
1122 }
1123 }
1124
1125 if (fc->default_permissions) {
1126 err = generic_permission(inode, mask);
1127
1128 /* If permission is denied, try to refresh file
1129 attributes. This is also needed, because the root
1130 node will at first have no permissions */
1131 if (err == -EACCES && !refreshed) {
1132 err = fuse_perm_getattr(inode, mask);
1133 if (!err)
1134 err = generic_permission(inode, mask);
1135 }
1136
1137 /* Note: the opposite of the above test does not
1138 exist. So if permissions are revoked this won't be
1139 noticed immediately, only after the attribute
1140 timeout has expired */
1141 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1142 err = fuse_access(inode, mask);
1143 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1144 if (!(inode->i_mode & S_IXUGO)) {
1145 if (refreshed)
1146 return -EACCES;
1147
1148 err = fuse_perm_getattr(inode, mask);
1149 if (!err && !(inode->i_mode & S_IXUGO))
1150 return -EACCES;
1151 }
1152 }
1153 return err;
1154 }
1155
1156 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1157 struct dir_context *ctx)
1158 {
1159 while (nbytes >= FUSE_NAME_OFFSET) {
1160 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1161 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1162 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1163 return -EIO;
1164 if (reclen > nbytes)
1165 break;
1166 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1167 return -EIO;
1168
1169 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1170 dirent->ino, dirent->type))
1171 break;
1172
1173 buf += reclen;
1174 nbytes -= reclen;
1175 ctx->pos = dirent->off;
1176 }
1177
1178 return 0;
1179 }
1180
1181 static int fuse_direntplus_link(struct file *file,
1182 struct fuse_direntplus *direntplus,
1183 u64 attr_version)
1184 {
1185 struct fuse_entry_out *o = &direntplus->entry_out;
1186 struct fuse_dirent *dirent = &direntplus->dirent;
1187 struct dentry *parent = file->f_path.dentry;
1188 struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1189 struct dentry *dentry;
1190 struct dentry *alias;
1191 struct inode *dir = d_inode(parent);
1192 struct fuse_conn *fc;
1193 struct inode *inode;
1194 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1195
1196 if (!o->nodeid) {
1197 /*
1198 * Unlike in the case of fuse_lookup, zero nodeid does not mean
1199 * ENOENT. Instead, it only means the userspace filesystem did
1200 * not want to return attributes/handle for this entry.
1201 *
1202 * So do nothing.
1203 */
1204 return 0;
1205 }
1206
1207 if (name.name[0] == '.') {
1208 /*
1209 * We could potentially refresh the attributes of the directory
1210 * and its parent?
1211 */
1212 if (name.len == 1)
1213 return 0;
1214 if (name.name[1] == '.' && name.len == 2)
1215 return 0;
1216 }
1217
1218 if (invalid_nodeid(o->nodeid))
1219 return -EIO;
1220 if (!fuse_valid_type(o->attr.mode))
1221 return -EIO;
1222
1223 fc = get_fuse_conn(dir);
1224
1225 name.hash = full_name_hash(parent, name.name, name.len);
1226 dentry = d_lookup(parent, &name);
1227 if (!dentry) {
1228 retry:
1229 dentry = d_alloc_parallel(parent, &name, &wq);
1230 if (IS_ERR(dentry))
1231 return PTR_ERR(dentry);
1232 }
1233 if (!d_in_lookup(dentry)) {
1234 struct fuse_inode *fi;
1235 inode = d_inode(dentry);
1236 if (!inode ||
1237 get_node_id(inode) != o->nodeid ||
1238 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1239 d_invalidate(dentry);
1240 dput(dentry);
1241 goto retry;
1242 }
1243 if (is_bad_inode(inode)) {
1244 dput(dentry);
1245 return -EIO;
1246 }
1247
1248 fi = get_fuse_inode(inode);
1249 spin_lock(&fc->lock);
1250 fi->nlookup++;
1251 spin_unlock(&fc->lock);
1252
1253 forget_all_cached_acls(inode);
1254 fuse_change_attributes(inode, &o->attr,
1255 entry_attr_timeout(o),
1256 attr_version);
1257 /*
1258 * The other branch comes via fuse_iget()
1259 * which bumps nlookup inside
1260 */
1261 } else {
1262 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1263 &o->attr, entry_attr_timeout(o),
1264 attr_version);
1265 if (!inode)
1266 inode = ERR_PTR(-ENOMEM);
1267
1268 alias = d_splice_alias(inode, dentry);
1269 d_lookup_done(dentry);
1270 if (alias) {
1271 dput(dentry);
1272 dentry = alias;
1273 }
1274 if (IS_ERR(dentry))
1275 return PTR_ERR(dentry);
1276 }
1277 if (fc->readdirplus_auto)
1278 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1279 fuse_change_entry_timeout(dentry, o);
1280
1281 dput(dentry);
1282 return 0;
1283 }
1284
1285 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1286 struct dir_context *ctx, u64 attr_version)
1287 {
1288 struct fuse_direntplus *direntplus;
1289 struct fuse_dirent *dirent;
1290 size_t reclen;
1291 int over = 0;
1292 int ret;
1293
1294 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1295 direntplus = (struct fuse_direntplus *) buf;
1296 dirent = &direntplus->dirent;
1297 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1298
1299 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1300 return -EIO;
1301 if (reclen > nbytes)
1302 break;
1303 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1304 return -EIO;
1305
1306 if (!over) {
1307 /* We fill entries into dstbuf only as much as
1308 it can hold. But we still continue iterating
1309 over remaining entries to link them. If not,
1310 we need to send a FORGET for each of those
1311 which we did not link.
1312 */
1313 over = !dir_emit(ctx, dirent->name, dirent->namelen,
1314 dirent->ino, dirent->type);
1315 ctx->pos = dirent->off;
1316 }
1317
1318 buf += reclen;
1319 nbytes -= reclen;
1320
1321 ret = fuse_direntplus_link(file, direntplus, attr_version);
1322 if (ret)
1323 fuse_force_forget(file, direntplus->entry_out.nodeid);
1324 }
1325
1326 return 0;
1327 }
1328
1329 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1330 {
1331 int plus, err;
1332 size_t nbytes;
1333 struct page *page;
1334 struct inode *inode = file_inode(file);
1335 struct fuse_conn *fc = get_fuse_conn(inode);
1336 struct fuse_req *req;
1337 u64 attr_version = 0;
1338
1339 if (is_bad_inode(inode))
1340 return -EIO;
1341
1342 req = fuse_get_req(fc, 1);
1343 if (IS_ERR(req))
1344 return PTR_ERR(req);
1345
1346 page = alloc_page(GFP_KERNEL);
1347 if (!page) {
1348 fuse_put_request(fc, req);
1349 return -ENOMEM;
1350 }
1351
1352 plus = fuse_use_readdirplus(inode, ctx);
1353 req->out.argpages = 1;
1354 req->num_pages = 1;
1355 req->pages[0] = page;
1356 req->page_descs[0].length = PAGE_SIZE;
1357 if (plus) {
1358 attr_version = fuse_get_attr_version(fc);
1359 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1360 FUSE_READDIRPLUS);
1361 } else {
1362 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1363 FUSE_READDIR);
1364 }
1365 fuse_lock_inode(inode);
1366 fuse_request_send(fc, req);
1367 fuse_unlock_inode(inode);
1368 nbytes = req->out.args[0].size;
1369 err = req->out.h.error;
1370 fuse_put_request(fc, req);
1371 if (!err) {
1372 if (plus) {
1373 err = parse_dirplusfile(page_address(page), nbytes,
1374 file, ctx,
1375 attr_version);
1376 } else {
1377 err = parse_dirfile(page_address(page), nbytes, file,
1378 ctx);
1379 }
1380 }
1381
1382 __free_page(page);
1383 fuse_invalidate_atime(inode);
1384 return err;
1385 }
1386
1387 static const char *fuse_get_link(struct dentry *dentry,
1388 struct inode *inode,
1389 struct delayed_call *done)
1390 {
1391 struct fuse_conn *fc = get_fuse_conn(inode);
1392 FUSE_ARGS(args);
1393 char *link;
1394 ssize_t ret;
1395
1396 if (!dentry)
1397 return ERR_PTR(-ECHILD);
1398
1399 link = kmalloc(PAGE_SIZE, GFP_KERNEL);
1400 if (!link)
1401 return ERR_PTR(-ENOMEM);
1402
1403 args.in.h.opcode = FUSE_READLINK;
1404 args.in.h.nodeid = get_node_id(inode);
1405 args.out.argvar = 1;
1406 args.out.numargs = 1;
1407 args.out.args[0].size = PAGE_SIZE - 1;
1408 args.out.args[0].value = link;
1409 ret = fuse_simple_request(fc, &args);
1410 if (ret < 0) {
1411 kfree(link);
1412 link = ERR_PTR(ret);
1413 } else {
1414 link[ret] = '\0';
1415 set_delayed_call(done, kfree_link, link);
1416 }
1417 fuse_invalidate_atime(inode);
1418 return link;
1419 }
1420
1421 static int fuse_dir_open(struct inode *inode, struct file *file)
1422 {
1423 return fuse_open_common(inode, file, true);
1424 }
1425
1426 static int fuse_dir_release(struct inode *inode, struct file *file)
1427 {
1428 fuse_release_common(file, FUSE_RELEASEDIR);
1429
1430 return 0;
1431 }
1432
1433 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1434 int datasync)
1435 {
1436 return fuse_fsync_common(file, start, end, datasync, 1);
1437 }
1438
1439 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1440 unsigned long arg)
1441 {
1442 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1443
1444 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1445 if (fc->minor < 18)
1446 return -ENOTTY;
1447
1448 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1449 }
1450
1451 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1452 unsigned long arg)
1453 {
1454 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1455
1456 if (fc->minor < 18)
1457 return -ENOTTY;
1458
1459 return fuse_ioctl_common(file, cmd, arg,
1460 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1461 }
1462
1463 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1464 {
1465 /* Always update if mtime is explicitly set */
1466 if (ivalid & ATTR_MTIME_SET)
1467 return true;
1468
1469 /* Or if kernel i_mtime is the official one */
1470 if (trust_local_mtime)
1471 return true;
1472
1473 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1474 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1475 return false;
1476
1477 /* In all other cases update */
1478 return true;
1479 }
1480
1481 static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
1482 struct fuse_setattr_in *arg, bool trust_local_cmtime)
1483 {
1484 unsigned ivalid = iattr->ia_valid;
1485
1486 if (ivalid & ATTR_MODE)
1487 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1488 if (ivalid & ATTR_UID)
1489 arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
1490 if (ivalid & ATTR_GID)
1491 arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
1492 if (ivalid & ATTR_SIZE)
1493 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1494 if (ivalid & ATTR_ATIME) {
1495 arg->valid |= FATTR_ATIME;
1496 arg->atime = iattr->ia_atime.tv_sec;
1497 arg->atimensec = iattr->ia_atime.tv_nsec;
1498 if (!(ivalid & ATTR_ATIME_SET))
1499 arg->valid |= FATTR_ATIME_NOW;
1500 }
1501 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1502 arg->valid |= FATTR_MTIME;
1503 arg->mtime = iattr->ia_mtime.tv_sec;
1504 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1505 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1506 arg->valid |= FATTR_MTIME_NOW;
1507 }
1508 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1509 arg->valid |= FATTR_CTIME;
1510 arg->ctime = iattr->ia_ctime.tv_sec;
1511 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1512 }
1513 }
1514
1515 /*
1516 * Prevent concurrent writepages on inode
1517 *
1518 * This is done by adding a negative bias to the inode write counter
1519 * and waiting for all pending writes to finish.
1520 */
1521 void fuse_set_nowrite(struct inode *inode)
1522 {
1523 struct fuse_conn *fc = get_fuse_conn(inode);
1524 struct fuse_inode *fi = get_fuse_inode(inode);
1525
1526 BUG_ON(!inode_is_locked(inode));
1527
1528 spin_lock(&fc->lock);
1529 BUG_ON(fi->writectr < 0);
1530 fi->writectr += FUSE_NOWRITE;
1531 spin_unlock(&fc->lock);
1532 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1533 }
1534
1535 /*
1536 * Allow writepages on inode
1537 *
1538 * Remove the bias from the writecounter and send any queued
1539 * writepages.
1540 */
1541 static void __fuse_release_nowrite(struct inode *inode)
1542 {
1543 struct fuse_inode *fi = get_fuse_inode(inode);
1544
1545 BUG_ON(fi->writectr != FUSE_NOWRITE);
1546 fi->writectr = 0;
1547 fuse_flush_writepages(inode);
1548 }
1549
1550 void fuse_release_nowrite(struct inode *inode)
1551 {
1552 struct fuse_conn *fc = get_fuse_conn(inode);
1553
1554 spin_lock(&fc->lock);
1555 __fuse_release_nowrite(inode);
1556 spin_unlock(&fc->lock);
1557 }
1558
1559 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1560 struct inode *inode,
1561 struct fuse_setattr_in *inarg_p,
1562 struct fuse_attr_out *outarg_p)
1563 {
1564 args->in.h.opcode = FUSE_SETATTR;
1565 args->in.h.nodeid = get_node_id(inode);
1566 args->in.numargs = 1;
1567 args->in.args[0].size = sizeof(*inarg_p);
1568 args->in.args[0].value = inarg_p;
1569 args->out.numargs = 1;
1570 args->out.args[0].size = sizeof(*outarg_p);
1571 args->out.args[0].value = outarg_p;
1572 }
1573
1574 /*
1575 * Flush inode->i_mtime to the server
1576 */
1577 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1578 {
1579 struct fuse_conn *fc = get_fuse_conn(inode);
1580 FUSE_ARGS(args);
1581 struct fuse_setattr_in inarg;
1582 struct fuse_attr_out outarg;
1583
1584 memset(&inarg, 0, sizeof(inarg));
1585 memset(&outarg, 0, sizeof(outarg));
1586
1587 inarg.valid = FATTR_MTIME;
1588 inarg.mtime = inode->i_mtime.tv_sec;
1589 inarg.mtimensec = inode->i_mtime.tv_nsec;
1590 if (fc->minor >= 23) {
1591 inarg.valid |= FATTR_CTIME;
1592 inarg.ctime = inode->i_ctime.tv_sec;
1593 inarg.ctimensec = inode->i_ctime.tv_nsec;
1594 }
1595 if (ff) {
1596 inarg.valid |= FATTR_FH;
1597 inarg.fh = ff->fh;
1598 }
1599 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1600
1601 return fuse_simple_request(fc, &args);
1602 }
1603
1604 /*
1605 * Set attributes, and at the same time refresh them.
1606 *
1607 * Truncation is slightly complicated, because the 'truncate' request
1608 * may fail, in which case we don't want to touch the mapping.
1609 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1610 * and the actual truncation by hand.
1611 */
1612 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1613 struct file *file)
1614 {
1615 struct inode *inode = d_inode(dentry);
1616 struct fuse_conn *fc = get_fuse_conn(inode);
1617 struct fuse_inode *fi = get_fuse_inode(inode);
1618 FUSE_ARGS(args);
1619 struct fuse_setattr_in inarg;
1620 struct fuse_attr_out outarg;
1621 bool is_truncate = false;
1622 bool is_wb = fc->writeback_cache;
1623 loff_t oldsize;
1624 int err;
1625 bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1626
1627 if (!fc->default_permissions)
1628 attr->ia_valid |= ATTR_FORCE;
1629
1630 err = setattr_prepare(dentry, attr);
1631 if (err)
1632 return err;
1633
1634 if (attr->ia_valid & ATTR_OPEN) {
1635 if (fc->atomic_o_trunc)
1636 return 0;
1637 file = NULL;
1638 }
1639
1640 if (attr->ia_valid & ATTR_SIZE)
1641 is_truncate = true;
1642
1643 if (is_truncate) {
1644 fuse_set_nowrite(inode);
1645 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1646 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1647 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1648 }
1649
1650 memset(&inarg, 0, sizeof(inarg));
1651 memset(&outarg, 0, sizeof(outarg));
1652 iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
1653 if (file) {
1654 struct fuse_file *ff = file->private_data;
1655 inarg.valid |= FATTR_FH;
1656 inarg.fh = ff->fh;
1657 }
1658 if (attr->ia_valid & ATTR_SIZE) {
1659 /* For mandatory locking in truncate */
1660 inarg.valid |= FATTR_LOCKOWNER;
1661 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1662 }
1663 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1664 err = fuse_simple_request(fc, &args);
1665 if (err) {
1666 if (err == -EINTR)
1667 fuse_invalidate_attr(inode);
1668 goto error;
1669 }
1670
1671 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1672 make_bad_inode(inode);
1673 err = -EIO;
1674 goto error;
1675 }
1676
1677 spin_lock(&fc->lock);
1678 /* the kernel maintains i_mtime locally */
1679 if (trust_local_cmtime) {
1680 if (attr->ia_valid & ATTR_MTIME)
1681 inode->i_mtime = attr->ia_mtime;
1682 if (attr->ia_valid & ATTR_CTIME)
1683 inode->i_ctime = attr->ia_ctime;
1684 /* FIXME: clear I_DIRTY_SYNC? */
1685 }
1686
1687 fuse_change_attributes_common(inode, &outarg.attr,
1688 attr_timeout(&outarg));
1689 oldsize = inode->i_size;
1690 /* see the comment in fuse_change_attributes() */
1691 if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1692 i_size_write(inode, outarg.attr.size);
1693
1694 if (is_truncate) {
1695 /* NOTE: this may release/reacquire fc->lock */
1696 __fuse_release_nowrite(inode);
1697 }
1698 spin_unlock(&fc->lock);
1699
1700 /*
1701 * Only call invalidate_inode_pages2() after removing
1702 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1703 */
1704 if ((is_truncate || !is_wb) &&
1705 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1706 truncate_pagecache(inode, outarg.attr.size);
1707 invalidate_inode_pages2(inode->i_mapping);
1708 }
1709
1710 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1711 return 0;
1712
1713 error:
1714 if (is_truncate)
1715 fuse_release_nowrite(inode);
1716
1717 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1718 return err;
1719 }
1720
1721 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1722 {
1723 struct inode *inode = d_inode(entry);
1724 struct fuse_conn *fc = get_fuse_conn(inode);
1725 struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
1726 int ret;
1727
1728 if (!fuse_allow_current_process(get_fuse_conn(inode)))
1729 return -EACCES;
1730
1731 if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
1732 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
1733 ATTR_MODE);
1734
1735 /*
1736 * The only sane way to reliably kill suid/sgid is to do it in
1737 * the userspace filesystem
1738 *
1739 * This should be done on write(), truncate() and chown().
1740 */
1741 if (!fc->handle_killpriv) {
1742 /*
1743 * ia_mode calculation may have used stale i_mode.
1744 * Refresh and recalculate.
1745 */
1746 ret = fuse_do_getattr(inode, NULL, file);
1747 if (ret)
1748 return ret;
1749
1750 attr->ia_mode = inode->i_mode;
1751 if (inode->i_mode & S_ISUID) {
1752 attr->ia_valid |= ATTR_MODE;
1753 attr->ia_mode &= ~S_ISUID;
1754 }
1755 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1756 attr->ia_valid |= ATTR_MODE;
1757 attr->ia_mode &= ~S_ISGID;
1758 }
1759 }
1760 }
1761 if (!attr->ia_valid)
1762 return 0;
1763
1764 ret = fuse_do_setattr(entry, attr, file);
1765 if (!ret) {
1766 /*
1767 * If filesystem supports acls it may have updated acl xattrs in
1768 * the filesystem, so forget cached acls for the inode.
1769 */
1770 if (fc->posix_acl)
1771 forget_all_cached_acls(inode);
1772
1773 /* Directory mode changed, may need to revalidate access */
1774 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
1775 fuse_invalidate_entry_cache(entry);
1776 }
1777 return ret;
1778 }
1779
1780 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1781 struct kstat *stat)
1782 {
1783 struct inode *inode = d_inode(entry);
1784 struct fuse_conn *fc = get_fuse_conn(inode);
1785
1786 if (!fuse_allow_current_process(fc))
1787 return -EACCES;
1788
1789 return fuse_update_attributes(inode, stat, NULL, NULL);
1790 }
1791
1792 static const struct inode_operations fuse_dir_inode_operations = {
1793 .lookup = fuse_lookup,
1794 .mkdir = fuse_mkdir,
1795 .symlink = fuse_symlink,
1796 .unlink = fuse_unlink,
1797 .rmdir = fuse_rmdir,
1798 .rename = fuse_rename2,
1799 .link = fuse_link,
1800 .setattr = fuse_setattr,
1801 .create = fuse_create,
1802 .atomic_open = fuse_atomic_open,
1803 .mknod = fuse_mknod,
1804 .permission = fuse_permission,
1805 .getattr = fuse_getattr,
1806 .listxattr = fuse_listxattr,
1807 .get_acl = fuse_get_acl,
1808 .set_acl = fuse_set_acl,
1809 };
1810
1811 static const struct file_operations fuse_dir_operations = {
1812 .llseek = generic_file_llseek,
1813 .read = generic_read_dir,
1814 .iterate_shared = fuse_readdir,
1815 .open = fuse_dir_open,
1816 .release = fuse_dir_release,
1817 .fsync = fuse_dir_fsync,
1818 .unlocked_ioctl = fuse_dir_ioctl,
1819 .compat_ioctl = fuse_dir_compat_ioctl,
1820 };
1821
1822 static const struct inode_operations fuse_common_inode_operations = {
1823 .setattr = fuse_setattr,
1824 .permission = fuse_permission,
1825 .getattr = fuse_getattr,
1826 .listxattr = fuse_listxattr,
1827 .get_acl = fuse_get_acl,
1828 .set_acl = fuse_set_acl,
1829 };
1830
1831 static const struct inode_operations fuse_symlink_inode_operations = {
1832 .setattr = fuse_setattr,
1833 .get_link = fuse_get_link,
1834 .getattr = fuse_getattr,
1835 .listxattr = fuse_listxattr,
1836 };
1837
1838 void fuse_init_common(struct inode *inode)
1839 {
1840 inode->i_op = &fuse_common_inode_operations;
1841 }
1842
1843 void fuse_init_dir(struct inode *inode)
1844 {
1845 inode->i_op = &fuse_dir_inode_operations;
1846 inode->i_fop = &fuse_dir_operations;
1847 }
1848
1849 void fuse_init_symlink(struct inode *inode)
1850 {
1851 inode->i_op = &fuse_symlink_inode_operations;
1852 }
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