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fuse: atomic_o_trunc should truncate pagecache
[mirror_ubuntu-bionic-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 = 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 static int fuse_update_get_attr(struct inode *inode, struct file *file,
927 struct kstat *stat)
928 {
929 struct fuse_inode *fi = get_fuse_inode(inode);
930 int err = 0;
931
932 if (time_before64(fi->i_time, get_jiffies_64())) {
933 forget_all_cached_acls(inode);
934 err = fuse_do_getattr(inode, stat, file);
935 } else if (stat) {
936 generic_fillattr(inode, stat);
937 stat->mode = fi->orig_i_mode;
938 stat->ino = fi->orig_ino;
939 }
940
941 return err;
942 }
943
944 int fuse_update_attributes(struct inode *inode, struct file *file)
945 {
946 return fuse_update_get_attr(inode, file, NULL);
947 }
948
949 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
950 u64 child_nodeid, struct qstr *name)
951 {
952 int err = -ENOTDIR;
953 struct inode *parent;
954 struct dentry *dir;
955 struct dentry *entry;
956
957 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
958 if (!parent)
959 return -ENOENT;
960
961 inode_lock(parent);
962 if (!S_ISDIR(parent->i_mode))
963 goto unlock;
964
965 err = -ENOENT;
966 dir = d_find_alias(parent);
967 if (!dir)
968 goto unlock;
969
970 name->hash = full_name_hash(dir, name->name, name->len);
971 entry = d_lookup(dir, name);
972 dput(dir);
973 if (!entry)
974 goto unlock;
975
976 fuse_invalidate_attr(parent);
977 fuse_invalidate_entry(entry);
978
979 if (child_nodeid != 0 && d_really_is_positive(entry)) {
980 inode_lock(d_inode(entry));
981 if (get_node_id(d_inode(entry)) != child_nodeid) {
982 err = -ENOENT;
983 goto badentry;
984 }
985 if (d_mountpoint(entry)) {
986 err = -EBUSY;
987 goto badentry;
988 }
989 if (d_is_dir(entry)) {
990 shrink_dcache_parent(entry);
991 if (!simple_empty(entry)) {
992 err = -ENOTEMPTY;
993 goto badentry;
994 }
995 d_inode(entry)->i_flags |= S_DEAD;
996 }
997 dont_mount(entry);
998 clear_nlink(d_inode(entry));
999 err = 0;
1000 badentry:
1001 inode_unlock(d_inode(entry));
1002 if (!err)
1003 d_delete(entry);
1004 } else {
1005 err = 0;
1006 }
1007 dput(entry);
1008
1009 unlock:
1010 inode_unlock(parent);
1011 iput(parent);
1012 return err;
1013 }
1014
1015 /*
1016 * Calling into a user-controlled filesystem gives the filesystem
1017 * daemon ptrace-like capabilities over the current process. This
1018 * means, that the filesystem daemon is able to record the exact
1019 * filesystem operations performed, and can also control the behavior
1020 * of the requester process in otherwise impossible ways. For example
1021 * it can delay the operation for arbitrary length of time allowing
1022 * DoS against the requester.
1023 *
1024 * For this reason only those processes can call into the filesystem,
1025 * for which the owner of the mount has ptrace privilege. This
1026 * excludes processes started by other users, suid or sgid processes.
1027 */
1028 int fuse_allow_current_process(struct fuse_conn *fc)
1029 {
1030 const struct cred *cred;
1031
1032 if (fc->allow_other)
1033 return current_in_userns(fc->user_ns);
1034
1035 cred = current_cred();
1036 if (uid_eq(cred->euid, fc->user_id) &&
1037 uid_eq(cred->suid, fc->user_id) &&
1038 uid_eq(cred->uid, fc->user_id) &&
1039 gid_eq(cred->egid, fc->group_id) &&
1040 gid_eq(cred->sgid, fc->group_id) &&
1041 gid_eq(cred->gid, fc->group_id))
1042 return 1;
1043
1044 return 0;
1045 }
1046
1047 static int fuse_access(struct inode *inode, int mask)
1048 {
1049 struct fuse_conn *fc = get_fuse_conn(inode);
1050 FUSE_ARGS(args);
1051 struct fuse_access_in inarg;
1052 int err;
1053
1054 BUG_ON(mask & MAY_NOT_BLOCK);
1055
1056 if (fc->no_access)
1057 return 0;
1058
1059 memset(&inarg, 0, sizeof(inarg));
1060 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1061 args.in.h.opcode = FUSE_ACCESS;
1062 args.in.h.nodeid = get_node_id(inode);
1063 args.in.numargs = 1;
1064 args.in.args[0].size = sizeof(inarg);
1065 args.in.args[0].value = &inarg;
1066 err = fuse_simple_request(fc, &args);
1067 if (err == -ENOSYS) {
1068 fc->no_access = 1;
1069 err = 0;
1070 }
1071 return err;
1072 }
1073
1074 static int fuse_perm_getattr(struct inode *inode, int mask)
1075 {
1076 if (mask & MAY_NOT_BLOCK)
1077 return -ECHILD;
1078
1079 forget_all_cached_acls(inode);
1080 return fuse_do_getattr(inode, NULL, NULL);
1081 }
1082
1083 /*
1084 * Check permission. The two basic access models of FUSE are:
1085 *
1086 * 1) Local access checking ('default_permissions' mount option) based
1087 * on file mode. This is the plain old disk filesystem permission
1088 * modell.
1089 *
1090 * 2) "Remote" access checking, where server is responsible for
1091 * checking permission in each inode operation. An exception to this
1092 * is if ->permission() was invoked from sys_access() in which case an
1093 * access request is sent. Execute permission is still checked
1094 * locally based on file mode.
1095 */
1096 static int fuse_permission(struct inode *inode, int mask)
1097 {
1098 struct fuse_conn *fc = get_fuse_conn(inode);
1099 bool refreshed = false;
1100 int err = 0;
1101
1102 if (!fuse_allow_current_process(fc))
1103 return -EACCES;
1104
1105 /*
1106 * If attributes are needed, refresh them before proceeding
1107 */
1108 if (fc->default_permissions ||
1109 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1110 struct fuse_inode *fi = get_fuse_inode(inode);
1111
1112 if (time_before64(fi->i_time, get_jiffies_64())) {
1113 refreshed = true;
1114
1115 err = fuse_perm_getattr(inode, mask);
1116 if (err)
1117 return err;
1118 }
1119 }
1120
1121 if (fc->default_permissions) {
1122 err = generic_permission(inode, mask);
1123
1124 /* If permission is denied, try to refresh file
1125 attributes. This is also needed, because the root
1126 node will at first have no permissions */
1127 if (err == -EACCES && !refreshed) {
1128 err = fuse_perm_getattr(inode, mask);
1129 if (!err)
1130 err = generic_permission(inode, mask);
1131 }
1132
1133 /* Note: the opposite of the above test does not
1134 exist. So if permissions are revoked this won't be
1135 noticed immediately, only after the attribute
1136 timeout has expired */
1137 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1138 err = fuse_access(inode, mask);
1139 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1140 if (!(inode->i_mode & S_IXUGO)) {
1141 if (refreshed)
1142 return -EACCES;
1143
1144 err = fuse_perm_getattr(inode, mask);
1145 if (!err && !(inode->i_mode & S_IXUGO))
1146 return -EACCES;
1147 }
1148 }
1149 return err;
1150 }
1151
1152 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1153 struct dir_context *ctx)
1154 {
1155 while (nbytes >= FUSE_NAME_OFFSET) {
1156 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1157 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1158 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1159 return -EIO;
1160 if (reclen > nbytes)
1161 break;
1162 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1163 return -EIO;
1164
1165 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1166 dirent->ino, dirent->type))
1167 break;
1168
1169 buf += reclen;
1170 nbytes -= reclen;
1171 ctx->pos = dirent->off;
1172 }
1173
1174 return 0;
1175 }
1176
1177 static int fuse_direntplus_link(struct file *file,
1178 struct fuse_direntplus *direntplus,
1179 u64 attr_version)
1180 {
1181 struct fuse_entry_out *o = &direntplus->entry_out;
1182 struct fuse_dirent *dirent = &direntplus->dirent;
1183 struct dentry *parent = file->f_path.dentry;
1184 struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1185 struct dentry *dentry;
1186 struct dentry *alias;
1187 struct inode *dir = d_inode(parent);
1188 struct fuse_conn *fc;
1189 struct inode *inode;
1190 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1191
1192 if (!o->nodeid) {
1193 /*
1194 * Unlike in the case of fuse_lookup, zero nodeid does not mean
1195 * ENOENT. Instead, it only means the userspace filesystem did
1196 * not want to return attributes/handle for this entry.
1197 *
1198 * So do nothing.
1199 */
1200 return 0;
1201 }
1202
1203 if (name.name[0] == '.') {
1204 /*
1205 * We could potentially refresh the attributes of the directory
1206 * and its parent?
1207 */
1208 if (name.len == 1)
1209 return 0;
1210 if (name.name[1] == '.' && name.len == 2)
1211 return 0;
1212 }
1213
1214 if (invalid_nodeid(o->nodeid))
1215 return -EIO;
1216 if (!fuse_valid_type(o->attr.mode))
1217 return -EIO;
1218
1219 fc = get_fuse_conn(dir);
1220
1221 name.hash = full_name_hash(parent, name.name, name.len);
1222 dentry = d_lookup(parent, &name);
1223 if (!dentry) {
1224 retry:
1225 dentry = d_alloc_parallel(parent, &name, &wq);
1226 if (IS_ERR(dentry))
1227 return PTR_ERR(dentry);
1228 }
1229 if (!d_in_lookup(dentry)) {
1230 struct fuse_inode *fi;
1231 inode = d_inode(dentry);
1232 if (!inode ||
1233 get_node_id(inode) != o->nodeid ||
1234 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1235 d_invalidate(dentry);
1236 dput(dentry);
1237 goto retry;
1238 }
1239 if (is_bad_inode(inode)) {
1240 dput(dentry);
1241 return -EIO;
1242 }
1243
1244 fi = get_fuse_inode(inode);
1245 spin_lock(&fc->lock);
1246 fi->nlookup++;
1247 spin_unlock(&fc->lock);
1248
1249 forget_all_cached_acls(inode);
1250 fuse_change_attributes(inode, &o->attr,
1251 entry_attr_timeout(o),
1252 attr_version);
1253 /*
1254 * The other branch comes via fuse_iget()
1255 * which bumps nlookup inside
1256 */
1257 } else {
1258 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1259 &o->attr, entry_attr_timeout(o),
1260 attr_version);
1261 if (!inode)
1262 inode = ERR_PTR(-ENOMEM);
1263
1264 alias = d_splice_alias(inode, dentry);
1265 d_lookup_done(dentry);
1266 if (alias) {
1267 dput(dentry);
1268 dentry = alias;
1269 }
1270 if (IS_ERR(dentry))
1271 return PTR_ERR(dentry);
1272 }
1273 if (fc->readdirplus_auto)
1274 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1275 fuse_change_entry_timeout(dentry, o);
1276
1277 dput(dentry);
1278 return 0;
1279 }
1280
1281 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1282 struct dir_context *ctx, u64 attr_version)
1283 {
1284 struct fuse_direntplus *direntplus;
1285 struct fuse_dirent *dirent;
1286 size_t reclen;
1287 int over = 0;
1288 int ret;
1289
1290 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1291 direntplus = (struct fuse_direntplus *) buf;
1292 dirent = &direntplus->dirent;
1293 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1294
1295 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1296 return -EIO;
1297 if (reclen > nbytes)
1298 break;
1299 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1300 return -EIO;
1301
1302 if (!over) {
1303 /* We fill entries into dstbuf only as much as
1304 it can hold. But we still continue iterating
1305 over remaining entries to link them. If not,
1306 we need to send a FORGET for each of those
1307 which we did not link.
1308 */
1309 over = !dir_emit(ctx, dirent->name, dirent->namelen,
1310 dirent->ino, dirent->type);
1311 if (!over)
1312 ctx->pos = dirent->off;
1313 }
1314
1315 buf += reclen;
1316 nbytes -= reclen;
1317
1318 ret = fuse_direntplus_link(file, direntplus, attr_version);
1319 if (ret)
1320 fuse_force_forget(file, direntplus->entry_out.nodeid);
1321 }
1322
1323 return 0;
1324 }
1325
1326 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1327 {
1328 int plus, err;
1329 size_t nbytes;
1330 struct page *page;
1331 struct inode *inode = file_inode(file);
1332 struct fuse_conn *fc = get_fuse_conn(inode);
1333 struct fuse_req *req;
1334 u64 attr_version = 0;
1335
1336 if (is_bad_inode(inode))
1337 return -EIO;
1338
1339 req = fuse_get_req(fc, 1);
1340 if (IS_ERR(req))
1341 return PTR_ERR(req);
1342
1343 page = alloc_page(GFP_KERNEL);
1344 if (!page) {
1345 fuse_put_request(fc, req);
1346 return -ENOMEM;
1347 }
1348
1349 plus = fuse_use_readdirplus(inode, ctx);
1350 req->out.argpages = 1;
1351 req->num_pages = 1;
1352 req->pages[0] = page;
1353 req->page_descs[0].length = PAGE_SIZE;
1354 if (plus) {
1355 attr_version = fuse_get_attr_version(fc);
1356 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1357 FUSE_READDIRPLUS);
1358 } else {
1359 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1360 FUSE_READDIR);
1361 }
1362 fuse_lock_inode(inode);
1363 fuse_request_send(fc, req);
1364 fuse_unlock_inode(inode);
1365 nbytes = req->out.args[0].size;
1366 err = req->out.h.error;
1367 fuse_put_request(fc, req);
1368 if (!err) {
1369 if (plus) {
1370 err = parse_dirplusfile(page_address(page), nbytes,
1371 file, ctx,
1372 attr_version);
1373 } else {
1374 err = parse_dirfile(page_address(page), nbytes, file,
1375 ctx);
1376 }
1377 }
1378
1379 __free_page(page);
1380 fuse_invalidate_atime(inode);
1381 return err;
1382 }
1383
1384 static const char *fuse_get_link(struct dentry *dentry,
1385 struct inode *inode,
1386 struct delayed_call *done)
1387 {
1388 struct fuse_conn *fc = get_fuse_conn(inode);
1389 FUSE_ARGS(args);
1390 char *link;
1391 ssize_t ret;
1392
1393 if (!dentry)
1394 return ERR_PTR(-ECHILD);
1395
1396 link = kmalloc(PAGE_SIZE, GFP_KERNEL);
1397 if (!link)
1398 return ERR_PTR(-ENOMEM);
1399
1400 args.in.h.opcode = FUSE_READLINK;
1401 args.in.h.nodeid = get_node_id(inode);
1402 args.out.argvar = 1;
1403 args.out.numargs = 1;
1404 args.out.args[0].size = PAGE_SIZE - 1;
1405 args.out.args[0].value = link;
1406 ret = fuse_simple_request(fc, &args);
1407 if (ret < 0) {
1408 kfree(link);
1409 link = ERR_PTR(ret);
1410 } else {
1411 link[ret] = '\0';
1412 set_delayed_call(done, kfree_link, link);
1413 }
1414 fuse_invalidate_atime(inode);
1415 return link;
1416 }
1417
1418 static int fuse_dir_open(struct inode *inode, struct file *file)
1419 {
1420 return fuse_open_common(inode, file, true);
1421 }
1422
1423 static int fuse_dir_release(struct inode *inode, struct file *file)
1424 {
1425 fuse_release_common(file, FUSE_RELEASEDIR);
1426
1427 return 0;
1428 }
1429
1430 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1431 int datasync)
1432 {
1433 return fuse_fsync_common(file, start, end, datasync, 1);
1434 }
1435
1436 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1437 unsigned long arg)
1438 {
1439 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1440
1441 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1442 if (fc->minor < 18)
1443 return -ENOTTY;
1444
1445 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1446 }
1447
1448 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1449 unsigned long arg)
1450 {
1451 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1452
1453 if (fc->minor < 18)
1454 return -ENOTTY;
1455
1456 return fuse_ioctl_common(file, cmd, arg,
1457 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1458 }
1459
1460 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1461 {
1462 /* Always update if mtime is explicitly set */
1463 if (ivalid & ATTR_MTIME_SET)
1464 return true;
1465
1466 /* Or if kernel i_mtime is the official one */
1467 if (trust_local_mtime)
1468 return true;
1469
1470 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1471 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1472 return false;
1473
1474 /* In all other cases update */
1475 return true;
1476 }
1477
1478 static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
1479 struct fuse_setattr_in *arg, bool trust_local_cmtime)
1480 {
1481 unsigned ivalid = iattr->ia_valid;
1482
1483 if (ivalid & ATTR_MODE)
1484 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1485 if (ivalid & ATTR_UID)
1486 arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
1487 if (ivalid & ATTR_GID)
1488 arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
1489 if (ivalid & ATTR_SIZE)
1490 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1491 if (ivalid & ATTR_ATIME) {
1492 arg->valid |= FATTR_ATIME;
1493 arg->atime = iattr->ia_atime.tv_sec;
1494 arg->atimensec = iattr->ia_atime.tv_nsec;
1495 if (!(ivalid & ATTR_ATIME_SET))
1496 arg->valid |= FATTR_ATIME_NOW;
1497 }
1498 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1499 arg->valid |= FATTR_MTIME;
1500 arg->mtime = iattr->ia_mtime.tv_sec;
1501 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1502 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1503 arg->valid |= FATTR_MTIME_NOW;
1504 }
1505 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1506 arg->valid |= FATTR_CTIME;
1507 arg->ctime = iattr->ia_ctime.tv_sec;
1508 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1509 }
1510 }
1511
1512 /*
1513 * Prevent concurrent writepages on inode
1514 *
1515 * This is done by adding a negative bias to the inode write counter
1516 * and waiting for all pending writes to finish.
1517 */
1518 void fuse_set_nowrite(struct inode *inode)
1519 {
1520 struct fuse_conn *fc = get_fuse_conn(inode);
1521 struct fuse_inode *fi = get_fuse_inode(inode);
1522
1523 BUG_ON(!inode_is_locked(inode));
1524
1525 spin_lock(&fc->lock);
1526 BUG_ON(fi->writectr < 0);
1527 fi->writectr += FUSE_NOWRITE;
1528 spin_unlock(&fc->lock);
1529 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1530 }
1531
1532 /*
1533 * Allow writepages on inode
1534 *
1535 * Remove the bias from the writecounter and send any queued
1536 * writepages.
1537 */
1538 static void __fuse_release_nowrite(struct inode *inode)
1539 {
1540 struct fuse_inode *fi = get_fuse_inode(inode);
1541
1542 BUG_ON(fi->writectr != FUSE_NOWRITE);
1543 fi->writectr = 0;
1544 fuse_flush_writepages(inode);
1545 }
1546
1547 void fuse_release_nowrite(struct inode *inode)
1548 {
1549 struct fuse_conn *fc = get_fuse_conn(inode);
1550
1551 spin_lock(&fc->lock);
1552 __fuse_release_nowrite(inode);
1553 spin_unlock(&fc->lock);
1554 }
1555
1556 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1557 struct inode *inode,
1558 struct fuse_setattr_in *inarg_p,
1559 struct fuse_attr_out *outarg_p)
1560 {
1561 args->in.h.opcode = FUSE_SETATTR;
1562 args->in.h.nodeid = get_node_id(inode);
1563 args->in.numargs = 1;
1564 args->in.args[0].size = sizeof(*inarg_p);
1565 args->in.args[0].value = inarg_p;
1566 args->out.numargs = 1;
1567 args->out.args[0].size = sizeof(*outarg_p);
1568 args->out.args[0].value = outarg_p;
1569 }
1570
1571 /*
1572 * Flush inode->i_mtime to the server
1573 */
1574 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1575 {
1576 struct fuse_conn *fc = get_fuse_conn(inode);
1577 FUSE_ARGS(args);
1578 struct fuse_setattr_in inarg;
1579 struct fuse_attr_out outarg;
1580
1581 memset(&inarg, 0, sizeof(inarg));
1582 memset(&outarg, 0, sizeof(outarg));
1583
1584 inarg.valid = FATTR_MTIME;
1585 inarg.mtime = inode->i_mtime.tv_sec;
1586 inarg.mtimensec = inode->i_mtime.tv_nsec;
1587 if (fc->minor >= 23) {
1588 inarg.valid |= FATTR_CTIME;
1589 inarg.ctime = inode->i_ctime.tv_sec;
1590 inarg.ctimensec = inode->i_ctime.tv_nsec;
1591 }
1592 if (ff) {
1593 inarg.valid |= FATTR_FH;
1594 inarg.fh = ff->fh;
1595 }
1596 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1597
1598 return fuse_simple_request(fc, &args);
1599 }
1600
1601 /*
1602 * Set attributes, and at the same time refresh them.
1603 *
1604 * Truncation is slightly complicated, because the 'truncate' request
1605 * may fail, in which case we don't want to touch the mapping.
1606 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1607 * and the actual truncation by hand.
1608 */
1609 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1610 struct file *file)
1611 {
1612 struct inode *inode = d_inode(dentry);
1613 struct fuse_conn *fc = get_fuse_conn(inode);
1614 struct fuse_inode *fi = get_fuse_inode(inode);
1615 FUSE_ARGS(args);
1616 struct fuse_setattr_in inarg;
1617 struct fuse_attr_out outarg;
1618 bool is_truncate = false;
1619 bool is_wb = fc->writeback_cache;
1620 loff_t oldsize;
1621 int err;
1622 bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1623
1624 if (!fc->default_permissions)
1625 attr->ia_valid |= ATTR_FORCE;
1626
1627 err = setattr_prepare(dentry, attr);
1628 if (err)
1629 return err;
1630
1631 if (attr->ia_valid & ATTR_OPEN) {
1632 /* This is coming from open(..., ... | O_TRUNC); */
1633 WARN_ON(!(attr->ia_valid & ATTR_SIZE));
1634 WARN_ON(attr->ia_size != 0);
1635 if (fc->atomic_o_trunc) {
1636 /*
1637 * No need to send request to userspace, since actual
1638 * truncation has already been done by OPEN. But still
1639 * need to truncate page cache.
1640 */
1641 i_size_write(inode, 0);
1642 truncate_pagecache(inode, 0);
1643 return 0;
1644 }
1645 file = NULL;
1646 }
1647
1648 if (attr->ia_valid & ATTR_SIZE)
1649 is_truncate = true;
1650
1651 if (is_truncate) {
1652 fuse_set_nowrite(inode);
1653 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1654 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1655 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1656 }
1657
1658 memset(&inarg, 0, sizeof(inarg));
1659 memset(&outarg, 0, sizeof(outarg));
1660 iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
1661 if (file) {
1662 struct fuse_file *ff = file->private_data;
1663 inarg.valid |= FATTR_FH;
1664 inarg.fh = ff->fh;
1665 }
1666 if (attr->ia_valid & ATTR_SIZE) {
1667 /* For mandatory locking in truncate */
1668 inarg.valid |= FATTR_LOCKOWNER;
1669 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1670 }
1671 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1672 err = fuse_simple_request(fc, &args);
1673 if (err) {
1674 if (err == -EINTR)
1675 fuse_invalidate_attr(inode);
1676 goto error;
1677 }
1678
1679 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1680 make_bad_inode(inode);
1681 err = -EIO;
1682 goto error;
1683 }
1684
1685 spin_lock(&fc->lock);
1686 /* the kernel maintains i_mtime locally */
1687 if (trust_local_cmtime) {
1688 if (attr->ia_valid & ATTR_MTIME)
1689 inode->i_mtime = attr->ia_mtime;
1690 if (attr->ia_valid & ATTR_CTIME)
1691 inode->i_ctime = attr->ia_ctime;
1692 /* FIXME: clear I_DIRTY_SYNC? */
1693 }
1694
1695 fuse_change_attributes_common(inode, &outarg.attr,
1696 attr_timeout(&outarg));
1697 oldsize = inode->i_size;
1698 /* see the comment in fuse_change_attributes() */
1699 if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1700 i_size_write(inode, outarg.attr.size);
1701
1702 if (is_truncate) {
1703 /* NOTE: this may release/reacquire fc->lock */
1704 __fuse_release_nowrite(inode);
1705 }
1706 spin_unlock(&fc->lock);
1707
1708 /*
1709 * Only call invalidate_inode_pages2() after removing
1710 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1711 */
1712 if ((is_truncate || !is_wb) &&
1713 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1714 truncate_pagecache(inode, outarg.attr.size);
1715 invalidate_inode_pages2(inode->i_mapping);
1716 }
1717
1718 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1719 return 0;
1720
1721 error:
1722 if (is_truncate)
1723 fuse_release_nowrite(inode);
1724
1725 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1726 return err;
1727 }
1728
1729 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1730 {
1731 struct inode *inode = d_inode(entry);
1732 struct fuse_conn *fc = get_fuse_conn(inode);
1733 struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
1734 int ret;
1735
1736 if (!fuse_allow_current_process(get_fuse_conn(inode)))
1737 return -EACCES;
1738
1739 if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
1740 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
1741 ATTR_MODE);
1742
1743 /*
1744 * The only sane way to reliably kill suid/sgid is to do it in
1745 * the userspace filesystem
1746 *
1747 * This should be done on write(), truncate() and chown().
1748 */
1749 if (!fc->handle_killpriv) {
1750 /*
1751 * ia_mode calculation may have used stale i_mode.
1752 * Refresh and recalculate.
1753 */
1754 ret = fuse_do_getattr(inode, NULL, file);
1755 if (ret)
1756 return ret;
1757
1758 attr->ia_mode = inode->i_mode;
1759 if (inode->i_mode & S_ISUID) {
1760 attr->ia_valid |= ATTR_MODE;
1761 attr->ia_mode &= ~S_ISUID;
1762 }
1763 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1764 attr->ia_valid |= ATTR_MODE;
1765 attr->ia_mode &= ~S_ISGID;
1766 }
1767 }
1768 }
1769 if (!attr->ia_valid)
1770 return 0;
1771
1772 ret = fuse_do_setattr(entry, attr, file);
1773 if (!ret) {
1774 /*
1775 * If filesystem supports acls it may have updated acl xattrs in
1776 * the filesystem, so forget cached acls for the inode.
1777 */
1778 if (fc->posix_acl)
1779 forget_all_cached_acls(inode);
1780
1781 /* Directory mode changed, may need to revalidate access */
1782 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
1783 fuse_invalidate_entry_cache(entry);
1784 }
1785 return ret;
1786 }
1787
1788 static int fuse_getattr(const struct path *path, struct kstat *stat,
1789 u32 request_mask, unsigned int flags)
1790 {
1791 struct inode *inode = d_inode(path->dentry);
1792 struct fuse_conn *fc = get_fuse_conn(inode);
1793
1794 if (!fuse_allow_current_process(fc))
1795 return -EACCES;
1796
1797 return fuse_update_get_attr(inode, NULL, stat);
1798 }
1799
1800 static const struct inode_operations fuse_dir_inode_operations = {
1801 .lookup = fuse_lookup,
1802 .mkdir = fuse_mkdir,
1803 .symlink = fuse_symlink,
1804 .unlink = fuse_unlink,
1805 .rmdir = fuse_rmdir,
1806 .rename = fuse_rename2,
1807 .link = fuse_link,
1808 .setattr = fuse_setattr,
1809 .create = fuse_create,
1810 .atomic_open = fuse_atomic_open,
1811 .mknod = fuse_mknod,
1812 .permission = fuse_permission,
1813 .getattr = fuse_getattr,
1814 .listxattr = fuse_listxattr,
1815 .get_acl = fuse_get_acl,
1816 .set_acl = fuse_set_acl,
1817 };
1818
1819 static const struct file_operations fuse_dir_operations = {
1820 .llseek = generic_file_llseek,
1821 .read = generic_read_dir,
1822 .iterate_shared = fuse_readdir,
1823 .open = fuse_dir_open,
1824 .release = fuse_dir_release,
1825 .fsync = fuse_dir_fsync,
1826 .unlocked_ioctl = fuse_dir_ioctl,
1827 .compat_ioctl = fuse_dir_compat_ioctl,
1828 };
1829
1830 static const struct inode_operations fuse_common_inode_operations = {
1831 .setattr = fuse_setattr,
1832 .permission = fuse_permission,
1833 .getattr = fuse_getattr,
1834 .listxattr = fuse_listxattr,
1835 .get_acl = fuse_get_acl,
1836 .set_acl = fuse_set_acl,
1837 };
1838
1839 static const struct inode_operations fuse_symlink_inode_operations = {
1840 .setattr = fuse_setattr,
1841 .get_link = fuse_get_link,
1842 .getattr = fuse_getattr,
1843 .listxattr = fuse_listxattr,
1844 };
1845
1846 void fuse_init_common(struct inode *inode)
1847 {
1848 inode->i_op = &fuse_common_inode_operations;
1849 }
1850
1851 void fuse_init_dir(struct inode *inode)
1852 {
1853 inode->i_op = &fuse_dir_inode_operations;
1854 inode->i_fop = &fuse_dir_operations;
1855 }
1856
1857 void fuse_init_symlink(struct inode *inode)
1858 {
1859 inode->i_op = &fuse_symlink_inode_operations;
1860 }
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