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1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/file.h>
13 #include <linux/sched.h>
14 #include <linux/namei.h>
15 #include <linux/slab.h>
16
17 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
18 {
19 struct fuse_conn *fc = get_fuse_conn(dir);
20 struct fuse_inode *fi = get_fuse_inode(dir);
21
22 if (!fc->do_readdirplus)
23 return false;
24 if (!fc->readdirplus_auto)
25 return true;
26 if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
27 return true;
28 if (ctx->pos == 0)
29 return true;
30 return false;
31 }
32
33 static void fuse_advise_use_readdirplus(struct inode *dir)
34 {
35 struct fuse_inode *fi = get_fuse_inode(dir);
36
37 set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
38 }
39
40 #if BITS_PER_LONG >= 64
41 static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
42 {
43 entry->d_time = time;
44 }
45
46 static inline u64 fuse_dentry_time(struct dentry *entry)
47 {
48 return entry->d_time;
49 }
50 #else
51 /*
52 * On 32 bit archs store the high 32 bits of time in d_fsdata
53 */
54 static void fuse_dentry_settime(struct dentry *entry, u64 time)
55 {
56 entry->d_time = time;
57 entry->d_fsdata = (void *) (unsigned long) (time >> 32);
58 }
59
60 static u64 fuse_dentry_time(struct dentry *entry)
61 {
62 return (u64) entry->d_time +
63 ((u64) (unsigned long) entry->d_fsdata << 32);
64 }
65 #endif
66
67 /*
68 * FUSE caches dentries and attributes with separate timeout. The
69 * time in jiffies until the dentry/attributes are valid is stored in
70 * dentry->d_time and fuse_inode->i_time respectively.
71 */
72
73 /*
74 * Calculate the time in jiffies until a dentry/attributes are valid
75 */
76 static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)
77 {
78 if (sec || nsec) {
79 struct timespec ts = {sec, nsec};
80 return get_jiffies_64() + timespec_to_jiffies(&ts);
81 } else
82 return 0;
83 }
84
85 /*
86 * Set dentry and possibly attribute timeouts from the lookup/mk*
87 * replies
88 */
89 static void fuse_change_entry_timeout(struct dentry *entry,
90 struct fuse_entry_out *o)
91 {
92 fuse_dentry_settime(entry,
93 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
94 }
95
96 static u64 attr_timeout(struct fuse_attr_out *o)
97 {
98 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
99 }
100
101 static u64 entry_attr_timeout(struct fuse_entry_out *o)
102 {
103 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
104 }
105
106 /*
107 * Mark the attributes as stale, so that at the next call to
108 * ->getattr() they will be fetched from userspace
109 */
110 void fuse_invalidate_attr(struct inode *inode)
111 {
112 get_fuse_inode(inode)->i_time = 0;
113 }
114
115 /**
116 * Mark the attributes as stale due to an atime change. Avoid the invalidate if
117 * atime is not used.
118 */
119 void fuse_invalidate_atime(struct inode *inode)
120 {
121 if (!IS_RDONLY(inode))
122 fuse_invalidate_attr(inode);
123 }
124
125 /*
126 * Just mark the entry as stale, so that a next attempt to look it up
127 * will result in a new lookup call to userspace
128 *
129 * This is called when a dentry is about to become negative and the
130 * timeout is unknown (unlink, rmdir, rename and in some cases
131 * lookup)
132 */
133 void fuse_invalidate_entry_cache(struct dentry *entry)
134 {
135 fuse_dentry_settime(entry, 0);
136 }
137
138 /*
139 * Same as fuse_invalidate_entry_cache(), but also try to remove the
140 * dentry from the hash
141 */
142 static void fuse_invalidate_entry(struct dentry *entry)
143 {
144 d_invalidate(entry);
145 fuse_invalidate_entry_cache(entry);
146 }
147
148 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
149 u64 nodeid, struct qstr *name,
150 struct fuse_entry_out *outarg)
151 {
152 memset(outarg, 0, sizeof(struct fuse_entry_out));
153 args->in.h.opcode = FUSE_LOOKUP;
154 args->in.h.nodeid = nodeid;
155 args->in.numargs = 1;
156 args->in.args[0].size = name->len + 1;
157 args->in.args[0].value = name->name;
158 args->out.numargs = 1;
159 args->out.args[0].size = sizeof(struct fuse_entry_out);
160 args->out.args[0].value = outarg;
161 }
162
163 u64 fuse_get_attr_version(struct fuse_conn *fc)
164 {
165 u64 curr_version;
166
167 /*
168 * The spin lock isn't actually needed on 64bit archs, but we
169 * don't yet care too much about such optimizations.
170 */
171 spin_lock(&fc->lock);
172 curr_version = fc->attr_version;
173 spin_unlock(&fc->lock);
174
175 return curr_version;
176 }
177
178 /*
179 * Check whether the dentry is still valid
180 *
181 * If the entry validity timeout has expired and the dentry is
182 * positive, try to redo the lookup. If the lookup results in a
183 * different inode, then let the VFS invalidate the dentry and redo
184 * the lookup once more. If the lookup results in the same inode,
185 * then refresh the attributes, timeouts and mark the dentry valid.
186 */
187 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
188 {
189 struct inode *inode;
190 struct dentry *parent;
191 struct fuse_conn *fc;
192 struct fuse_inode *fi;
193 int ret;
194
195 inode = d_inode_rcu(entry);
196 if (inode && is_bad_inode(inode))
197 goto invalid;
198 else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
199 (flags & LOOKUP_REVAL)) {
200 struct fuse_entry_out outarg;
201 FUSE_ARGS(args);
202 struct fuse_forget_link *forget;
203 u64 attr_version;
204
205 /* For negative dentries, always do a fresh lookup */
206 if (!inode)
207 goto invalid;
208
209 ret = -ECHILD;
210 if (flags & LOOKUP_RCU)
211 goto out;
212
213 fc = get_fuse_conn(inode);
214
215 forget = fuse_alloc_forget();
216 ret = -ENOMEM;
217 if (!forget)
218 goto out;
219
220 attr_version = fuse_get_attr_version(fc);
221
222 parent = dget_parent(entry);
223 fuse_lookup_init(fc, &args, get_node_id(d_inode(parent)),
224 &entry->d_name, &outarg);
225 ret = fuse_simple_request(fc, &args);
226 dput(parent);
227 /* Zero nodeid is same as -ENOENT */
228 if (!ret && !outarg.nodeid)
229 ret = -ENOENT;
230 if (!ret) {
231 fi = get_fuse_inode(inode);
232 if (outarg.nodeid != get_node_id(inode)) {
233 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
234 goto invalid;
235 }
236 spin_lock(&fc->lock);
237 fi->nlookup++;
238 spin_unlock(&fc->lock);
239 }
240 kfree(forget);
241 if (ret == -ENOMEM)
242 goto out;
243 if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
244 goto invalid;
245
246 fuse_change_attributes(inode, &outarg.attr,
247 entry_attr_timeout(&outarg),
248 attr_version);
249 fuse_change_entry_timeout(entry, &outarg);
250 } else if (inode) {
251 fi = get_fuse_inode(inode);
252 if (flags & LOOKUP_RCU) {
253 if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
254 return -ECHILD;
255 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
256 parent = dget_parent(entry);
257 fuse_advise_use_readdirplus(d_inode(parent));
258 dput(parent);
259 }
260 }
261 ret = 1;
262 out:
263 return ret;
264
265 invalid:
266 ret = 0;
267 goto out;
268 }
269
270 static int invalid_nodeid(u64 nodeid)
271 {
272 return !nodeid || nodeid == FUSE_ROOT_ID;
273 }
274
275 const struct dentry_operations fuse_dentry_operations = {
276 .d_revalidate = fuse_dentry_revalidate,
277 };
278
279 int fuse_valid_type(int m)
280 {
281 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
282 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
283 }
284
285 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
286 struct fuse_entry_out *outarg, struct inode **inode)
287 {
288 struct fuse_conn *fc = get_fuse_conn_super(sb);
289 FUSE_ARGS(args);
290 struct fuse_forget_link *forget;
291 u64 attr_version;
292 int err;
293
294 *inode = NULL;
295 err = -ENAMETOOLONG;
296 if (name->len > FUSE_NAME_MAX)
297 goto out;
298
299
300 forget = fuse_alloc_forget();
301 err = -ENOMEM;
302 if (!forget)
303 goto out;
304
305 attr_version = fuse_get_attr_version(fc);
306
307 fuse_lookup_init(fc, &args, nodeid, name, outarg);
308 err = fuse_simple_request(fc, &args);
309 /* Zero nodeid is same as -ENOENT, but with valid timeout */
310 if (err || !outarg->nodeid)
311 goto out_put_forget;
312
313 err = -EIO;
314 if (!outarg->nodeid)
315 goto out_put_forget;
316 if (!fuse_valid_type(outarg->attr.mode))
317 goto out_put_forget;
318
319 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
320 &outarg->attr, entry_attr_timeout(outarg),
321 attr_version);
322 err = -ENOMEM;
323 if (!*inode) {
324 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
325 goto out;
326 }
327 err = 0;
328
329 out_put_forget:
330 kfree(forget);
331 out:
332 return err;
333 }
334
335 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
336 unsigned int flags)
337 {
338 int err;
339 struct fuse_entry_out outarg;
340 struct inode *inode;
341 struct dentry *newent;
342 bool outarg_valid = true;
343
344 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
345 &outarg, &inode);
346 if (err == -ENOENT) {
347 outarg_valid = false;
348 err = 0;
349 }
350 if (err)
351 goto out_err;
352
353 err = -EIO;
354 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
355 goto out_iput;
356
357 newent = d_splice_alias(inode, entry);
358 err = PTR_ERR(newent);
359 if (IS_ERR(newent))
360 goto out_err;
361
362 entry = newent ? newent : entry;
363 if (outarg_valid)
364 fuse_change_entry_timeout(entry, &outarg);
365 else
366 fuse_invalidate_entry_cache(entry);
367
368 fuse_advise_use_readdirplus(dir);
369 return newent;
370
371 out_iput:
372 iput(inode);
373 out_err:
374 return ERR_PTR(err);
375 }
376
377 /*
378 * Atomic create+open operation
379 *
380 * If the filesystem doesn't support this, then fall back to separate
381 * 'mknod' + 'open' requests.
382 */
383 static int fuse_create_open(struct inode *dir, struct dentry *entry,
384 struct file *file, unsigned flags,
385 umode_t mode, int *opened)
386 {
387 int err;
388 struct inode *inode;
389 struct fuse_conn *fc = get_fuse_conn(dir);
390 FUSE_ARGS(args);
391 struct fuse_forget_link *forget;
392 struct fuse_create_in inarg;
393 struct fuse_open_out outopen;
394 struct fuse_entry_out outentry;
395 struct fuse_file *ff;
396
397 /* Userspace expects S_IFREG in create mode */
398 BUG_ON((mode & S_IFMT) != S_IFREG);
399
400 forget = fuse_alloc_forget();
401 err = -ENOMEM;
402 if (!forget)
403 goto out_err;
404
405 err = -ENOMEM;
406 ff = fuse_file_alloc(fc);
407 if (!ff)
408 goto out_put_forget_req;
409
410 if (!fc->dont_mask)
411 mode &= ~current_umask();
412
413 flags &= ~O_NOCTTY;
414 memset(&inarg, 0, sizeof(inarg));
415 memset(&outentry, 0, sizeof(outentry));
416 inarg.flags = flags;
417 inarg.mode = mode;
418 inarg.umask = current_umask();
419 args.in.h.opcode = FUSE_CREATE;
420 args.in.h.nodeid = get_node_id(dir);
421 args.in.numargs = 2;
422 args.in.args[0].size = sizeof(inarg);
423 args.in.args[0].value = &inarg;
424 args.in.args[1].size = entry->d_name.len + 1;
425 args.in.args[1].value = entry->d_name.name;
426 args.out.numargs = 2;
427 args.out.args[0].size = sizeof(outentry);
428 args.out.args[0].value = &outentry;
429 args.out.args[1].size = sizeof(outopen);
430 args.out.args[1].value = &outopen;
431 err = fuse_simple_request(fc, &args);
432 if (err)
433 goto out_free_ff;
434
435 err = -EIO;
436 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
437 goto out_free_ff;
438
439 ff->fh = outopen.fh;
440 ff->nodeid = outentry.nodeid;
441 ff->open_flags = outopen.open_flags;
442 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
443 &outentry.attr, entry_attr_timeout(&outentry), 0);
444 if (!inode) {
445 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
446 fuse_sync_release(ff, flags);
447 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
448 err = -ENOMEM;
449 goto out_err;
450 }
451 kfree(forget);
452 d_instantiate(entry, inode);
453 fuse_change_entry_timeout(entry, &outentry);
454 fuse_invalidate_attr(dir);
455 err = finish_open(file, entry, generic_file_open, opened);
456 if (err) {
457 fuse_sync_release(ff, flags);
458 } else {
459 file->private_data = fuse_file_get(ff);
460 fuse_finish_open(inode, file);
461 }
462 return err;
463
464 out_free_ff:
465 fuse_file_free(ff);
466 out_put_forget_req:
467 kfree(forget);
468 out_err:
469 return err;
470 }
471
472 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);
473 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
474 struct file *file, unsigned flags,
475 umode_t mode, int *opened)
476 {
477 int err;
478 struct fuse_conn *fc = get_fuse_conn(dir);
479 struct dentry *res = NULL;
480
481 if (d_unhashed(entry)) {
482 res = fuse_lookup(dir, entry, 0);
483 if (IS_ERR(res))
484 return PTR_ERR(res);
485
486 if (res)
487 entry = res;
488 }
489
490 if (!(flags & O_CREAT) || d_really_is_positive(entry))
491 goto no_open;
492
493 /* Only creates */
494 *opened |= FILE_CREATED;
495
496 if (fc->no_create)
497 goto mknod;
498
499 err = fuse_create_open(dir, entry, file, flags, mode, opened);
500 if (err == -ENOSYS) {
501 fc->no_create = 1;
502 goto mknod;
503 }
504 out_dput:
505 dput(res);
506 return err;
507
508 mknod:
509 err = fuse_mknod(dir, entry, mode, 0);
510 if (err)
511 goto out_dput;
512 no_open:
513 return finish_no_open(file, res);
514 }
515
516 /*
517 * Code shared between mknod, mkdir, symlink and link
518 */
519 static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
520 struct inode *dir, struct dentry *entry,
521 umode_t mode)
522 {
523 struct fuse_entry_out outarg;
524 struct inode *inode;
525 int err;
526 struct fuse_forget_link *forget;
527
528 forget = fuse_alloc_forget();
529 if (!forget)
530 return -ENOMEM;
531
532 memset(&outarg, 0, sizeof(outarg));
533 args->in.h.nodeid = get_node_id(dir);
534 args->out.numargs = 1;
535 args->out.args[0].size = sizeof(outarg);
536 args->out.args[0].value = &outarg;
537 err = fuse_simple_request(fc, args);
538 if (err)
539 goto out_put_forget_req;
540
541 err = -EIO;
542 if (invalid_nodeid(outarg.nodeid))
543 goto out_put_forget_req;
544
545 if ((outarg.attr.mode ^ mode) & S_IFMT)
546 goto out_put_forget_req;
547
548 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
549 &outarg.attr, entry_attr_timeout(&outarg), 0);
550 if (!inode) {
551 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
552 return -ENOMEM;
553 }
554 kfree(forget);
555
556 err = d_instantiate_no_diralias(entry, inode);
557 if (err)
558 return err;
559
560 fuse_change_entry_timeout(entry, &outarg);
561 fuse_invalidate_attr(dir);
562 return 0;
563
564 out_put_forget_req:
565 kfree(forget);
566 return err;
567 }
568
569 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
570 dev_t rdev)
571 {
572 struct fuse_mknod_in inarg;
573 struct fuse_conn *fc = get_fuse_conn(dir);
574 FUSE_ARGS(args);
575
576 if (!fc->dont_mask)
577 mode &= ~current_umask();
578
579 memset(&inarg, 0, sizeof(inarg));
580 inarg.mode = mode;
581 inarg.rdev = new_encode_dev(rdev);
582 inarg.umask = current_umask();
583 args.in.h.opcode = FUSE_MKNOD;
584 args.in.numargs = 2;
585 args.in.args[0].size = sizeof(inarg);
586 args.in.args[0].value = &inarg;
587 args.in.args[1].size = entry->d_name.len + 1;
588 args.in.args[1].value = entry->d_name.name;
589 return create_new_entry(fc, &args, dir, entry, mode);
590 }
591
592 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
593 bool excl)
594 {
595 return fuse_mknod(dir, entry, mode, 0);
596 }
597
598 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
599 {
600 struct fuse_mkdir_in inarg;
601 struct fuse_conn *fc = get_fuse_conn(dir);
602 FUSE_ARGS(args);
603
604 if (!fc->dont_mask)
605 mode &= ~current_umask();
606
607 memset(&inarg, 0, sizeof(inarg));
608 inarg.mode = mode;
609 inarg.umask = current_umask();
610 args.in.h.opcode = FUSE_MKDIR;
611 args.in.numargs = 2;
612 args.in.args[0].size = sizeof(inarg);
613 args.in.args[0].value = &inarg;
614 args.in.args[1].size = entry->d_name.len + 1;
615 args.in.args[1].value = entry->d_name.name;
616 return create_new_entry(fc, &args, dir, entry, S_IFDIR);
617 }
618
619 static int fuse_symlink(struct inode *dir, struct dentry *entry,
620 const char *link)
621 {
622 struct fuse_conn *fc = get_fuse_conn(dir);
623 unsigned len = strlen(link) + 1;
624 FUSE_ARGS(args);
625
626 args.in.h.opcode = FUSE_SYMLINK;
627 args.in.numargs = 2;
628 args.in.args[0].size = entry->d_name.len + 1;
629 args.in.args[0].value = entry->d_name.name;
630 args.in.args[1].size = len;
631 args.in.args[1].value = link;
632 return create_new_entry(fc, &args, dir, entry, S_IFLNK);
633 }
634
635 static inline void fuse_update_ctime(struct inode *inode)
636 {
637 if (!IS_NOCMTIME(inode)) {
638 inode->i_ctime = current_fs_time(inode->i_sb);
639 mark_inode_dirty_sync(inode);
640 }
641 }
642
643 static int fuse_unlink(struct inode *dir, struct dentry *entry)
644 {
645 int err;
646 struct fuse_conn *fc = get_fuse_conn(dir);
647 FUSE_ARGS(args);
648
649 args.in.h.opcode = FUSE_UNLINK;
650 args.in.h.nodeid = get_node_id(dir);
651 args.in.numargs = 1;
652 args.in.args[0].size = entry->d_name.len + 1;
653 args.in.args[0].value = entry->d_name.name;
654 err = fuse_simple_request(fc, &args);
655 if (!err) {
656 struct inode *inode = d_inode(entry);
657 struct fuse_inode *fi = get_fuse_inode(inode);
658
659 spin_lock(&fc->lock);
660 fi->attr_version = ++fc->attr_version;
661 /*
662 * If i_nlink == 0 then unlink doesn't make sense, yet this can
663 * happen if userspace filesystem is careless. It would be
664 * difficult to enforce correct nlink usage so just ignore this
665 * condition here
666 */
667 if (inode->i_nlink > 0)
668 drop_nlink(inode);
669 spin_unlock(&fc->lock);
670 fuse_invalidate_attr(inode);
671 fuse_invalidate_attr(dir);
672 fuse_invalidate_entry_cache(entry);
673 fuse_update_ctime(inode);
674 } else if (err == -EINTR)
675 fuse_invalidate_entry(entry);
676 return err;
677 }
678
679 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
680 {
681 int err;
682 struct fuse_conn *fc = get_fuse_conn(dir);
683 FUSE_ARGS(args);
684
685 args.in.h.opcode = FUSE_RMDIR;
686 args.in.h.nodeid = get_node_id(dir);
687 args.in.numargs = 1;
688 args.in.args[0].size = entry->d_name.len + 1;
689 args.in.args[0].value = entry->d_name.name;
690 err = fuse_simple_request(fc, &args);
691 if (!err) {
692 clear_nlink(d_inode(entry));
693 fuse_invalidate_attr(dir);
694 fuse_invalidate_entry_cache(entry);
695 } else if (err == -EINTR)
696 fuse_invalidate_entry(entry);
697 return err;
698 }
699
700 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
701 struct inode *newdir, struct dentry *newent,
702 unsigned int flags, int opcode, size_t argsize)
703 {
704 int err;
705 struct fuse_rename2_in inarg;
706 struct fuse_conn *fc = get_fuse_conn(olddir);
707 FUSE_ARGS(args);
708
709 memset(&inarg, 0, argsize);
710 inarg.newdir = get_node_id(newdir);
711 inarg.flags = flags;
712 args.in.h.opcode = opcode;
713 args.in.h.nodeid = get_node_id(olddir);
714 args.in.numargs = 3;
715 args.in.args[0].size = argsize;
716 args.in.args[0].value = &inarg;
717 args.in.args[1].size = oldent->d_name.len + 1;
718 args.in.args[1].value = oldent->d_name.name;
719 args.in.args[2].size = newent->d_name.len + 1;
720 args.in.args[2].value = newent->d_name.name;
721 err = fuse_simple_request(fc, &args);
722 if (!err) {
723 /* ctime changes */
724 fuse_invalidate_attr(d_inode(oldent));
725 fuse_update_ctime(d_inode(oldent));
726
727 if (flags & RENAME_EXCHANGE) {
728 fuse_invalidate_attr(d_inode(newent));
729 fuse_update_ctime(d_inode(newent));
730 }
731
732 fuse_invalidate_attr(olddir);
733 if (olddir != newdir)
734 fuse_invalidate_attr(newdir);
735
736 /* newent will end up negative */
737 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) {
738 fuse_invalidate_attr(d_inode(newent));
739 fuse_invalidate_entry_cache(newent);
740 fuse_update_ctime(d_inode(newent));
741 }
742 } else if (err == -EINTR) {
743 /* If request was interrupted, DEITY only knows if the
744 rename actually took place. If the invalidation
745 fails (e.g. some process has CWD under the renamed
746 directory), then there can be inconsistency between
747 the dcache and the real filesystem. Tough luck. */
748 fuse_invalidate_entry(oldent);
749 if (d_really_is_positive(newent))
750 fuse_invalidate_entry(newent);
751 }
752
753 return err;
754 }
755
756 static int fuse_rename2(struct inode *olddir, struct dentry *oldent,
757 struct inode *newdir, struct dentry *newent,
758 unsigned int flags)
759 {
760 struct fuse_conn *fc = get_fuse_conn(olddir);
761 int err;
762
763 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
764 return -EINVAL;
765
766 if (flags) {
767 if (fc->no_rename2 || fc->minor < 23)
768 return -EINVAL;
769
770 err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
771 FUSE_RENAME2,
772 sizeof(struct fuse_rename2_in));
773 if (err == -ENOSYS) {
774 fc->no_rename2 = 1;
775 err = -EINVAL;
776 }
777 } else {
778 err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
779 FUSE_RENAME,
780 sizeof(struct fuse_rename_in));
781 }
782
783 return err;
784 }
785
786 static int fuse_link(struct dentry *entry, struct inode *newdir,
787 struct dentry *newent)
788 {
789 int err;
790 struct fuse_link_in inarg;
791 struct inode *inode = d_inode(entry);
792 struct fuse_conn *fc = get_fuse_conn(inode);
793 FUSE_ARGS(args);
794
795 memset(&inarg, 0, sizeof(inarg));
796 inarg.oldnodeid = get_node_id(inode);
797 args.in.h.opcode = FUSE_LINK;
798 args.in.numargs = 2;
799 args.in.args[0].size = sizeof(inarg);
800 args.in.args[0].value = &inarg;
801 args.in.args[1].size = newent->d_name.len + 1;
802 args.in.args[1].value = newent->d_name.name;
803 err = create_new_entry(fc, &args, newdir, newent, inode->i_mode);
804 /* Contrary to "normal" filesystems it can happen that link
805 makes two "logical" inodes point to the same "physical"
806 inode. We invalidate the attributes of the old one, so it
807 will reflect changes in the backing inode (link count,
808 etc.)
809 */
810 if (!err) {
811 struct fuse_inode *fi = get_fuse_inode(inode);
812
813 spin_lock(&fc->lock);
814 fi->attr_version = ++fc->attr_version;
815 inc_nlink(inode);
816 spin_unlock(&fc->lock);
817 fuse_invalidate_attr(inode);
818 fuse_update_ctime(inode);
819 } else if (err == -EINTR) {
820 fuse_invalidate_attr(inode);
821 }
822 return err;
823 }
824
825 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
826 struct kstat *stat)
827 {
828 unsigned int blkbits;
829 struct fuse_conn *fc = get_fuse_conn(inode);
830
831 /* see the comment in fuse_change_attributes() */
832 if (fc->writeback_cache && S_ISREG(inode->i_mode)) {
833 attr->size = i_size_read(inode);
834 attr->mtime = inode->i_mtime.tv_sec;
835 attr->mtimensec = inode->i_mtime.tv_nsec;
836 attr->ctime = inode->i_ctime.tv_sec;
837 attr->ctimensec = inode->i_ctime.tv_nsec;
838 }
839
840 stat->dev = inode->i_sb->s_dev;
841 stat->ino = attr->ino;
842 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
843 stat->nlink = attr->nlink;
844 stat->uid = make_kuid(&init_user_ns, attr->uid);
845 stat->gid = make_kgid(&init_user_ns, attr->gid);
846 stat->rdev = inode->i_rdev;
847 stat->atime.tv_sec = attr->atime;
848 stat->atime.tv_nsec = attr->atimensec;
849 stat->mtime.tv_sec = attr->mtime;
850 stat->mtime.tv_nsec = attr->mtimensec;
851 stat->ctime.tv_sec = attr->ctime;
852 stat->ctime.tv_nsec = attr->ctimensec;
853 stat->size = attr->size;
854 stat->blocks = attr->blocks;
855
856 if (attr->blksize != 0)
857 blkbits = ilog2(attr->blksize);
858 else
859 blkbits = inode->i_sb->s_blocksize_bits;
860
861 stat->blksize = 1 << blkbits;
862 }
863
864 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
865 struct file *file)
866 {
867 int err;
868 struct fuse_getattr_in inarg;
869 struct fuse_attr_out outarg;
870 struct fuse_conn *fc = get_fuse_conn(inode);
871 FUSE_ARGS(args);
872 u64 attr_version;
873
874 attr_version = fuse_get_attr_version(fc);
875
876 memset(&inarg, 0, sizeof(inarg));
877 memset(&outarg, 0, sizeof(outarg));
878 /* Directories have separate file-handle space */
879 if (file && S_ISREG(inode->i_mode)) {
880 struct fuse_file *ff = file->private_data;
881
882 inarg.getattr_flags |= FUSE_GETATTR_FH;
883 inarg.fh = ff->fh;
884 }
885 args.in.h.opcode = FUSE_GETATTR;
886 args.in.h.nodeid = get_node_id(inode);
887 args.in.numargs = 1;
888 args.in.args[0].size = sizeof(inarg);
889 args.in.args[0].value = &inarg;
890 args.out.numargs = 1;
891 args.out.args[0].size = sizeof(outarg);
892 args.out.args[0].value = &outarg;
893 err = fuse_simple_request(fc, &args);
894 if (!err) {
895 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
896 make_bad_inode(inode);
897 err = -EIO;
898 } else {
899 fuse_change_attributes(inode, &outarg.attr,
900 attr_timeout(&outarg),
901 attr_version);
902 if (stat)
903 fuse_fillattr(inode, &outarg.attr, stat);
904 }
905 }
906 return err;
907 }
908
909 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
910 struct file *file, bool *refreshed)
911 {
912 struct fuse_inode *fi = get_fuse_inode(inode);
913 int err;
914 bool r;
915
916 if (time_before64(fi->i_time, get_jiffies_64())) {
917 r = true;
918 err = fuse_do_getattr(inode, stat, file);
919 } else {
920 r = false;
921 err = 0;
922 if (stat) {
923 generic_fillattr(inode, stat);
924 stat->mode = fi->orig_i_mode;
925 stat->ino = fi->orig_ino;
926 }
927 }
928
929 if (refreshed != NULL)
930 *refreshed = r;
931
932 return err;
933 }
934
935 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
936 u64 child_nodeid, struct qstr *name)
937 {
938 int err = -ENOTDIR;
939 struct inode *parent;
940 struct dentry *dir;
941 struct dentry *entry;
942
943 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
944 if (!parent)
945 return -ENOENT;
946
947 inode_lock(parent);
948 if (!S_ISDIR(parent->i_mode))
949 goto unlock;
950
951 err = -ENOENT;
952 dir = d_find_alias(parent);
953 if (!dir)
954 goto unlock;
955
956 name->hash = full_name_hash(dir, name->name, name->len);
957 entry = d_lookup(dir, name);
958 dput(dir);
959 if (!entry)
960 goto unlock;
961
962 fuse_invalidate_attr(parent);
963 fuse_invalidate_entry(entry);
964
965 if (child_nodeid != 0 && d_really_is_positive(entry)) {
966 inode_lock(d_inode(entry));
967 if (get_node_id(d_inode(entry)) != child_nodeid) {
968 err = -ENOENT;
969 goto badentry;
970 }
971 if (d_mountpoint(entry)) {
972 err = -EBUSY;
973 goto badentry;
974 }
975 if (d_is_dir(entry)) {
976 shrink_dcache_parent(entry);
977 if (!simple_empty(entry)) {
978 err = -ENOTEMPTY;
979 goto badentry;
980 }
981 d_inode(entry)->i_flags |= S_DEAD;
982 }
983 dont_mount(entry);
984 clear_nlink(d_inode(entry));
985 err = 0;
986 badentry:
987 inode_unlock(d_inode(entry));
988 if (!err)
989 d_delete(entry);
990 } else {
991 err = 0;
992 }
993 dput(entry);
994
995 unlock:
996 inode_unlock(parent);
997 iput(parent);
998 return err;
999 }
1000
1001 /*
1002 * Calling into a user-controlled filesystem gives the filesystem
1003 * daemon ptrace-like capabilities over the current process. This
1004 * means, that the filesystem daemon is able to record the exact
1005 * filesystem operations performed, and can also control the behavior
1006 * of the requester process in otherwise impossible ways. For example
1007 * it can delay the operation for arbitrary length of time allowing
1008 * DoS against the requester.
1009 *
1010 * For this reason only those processes can call into the filesystem,
1011 * for which the owner of the mount has ptrace privilege. This
1012 * excludes processes started by other users, suid or sgid processes.
1013 */
1014 int fuse_allow_current_process(struct fuse_conn *fc)
1015 {
1016 const struct cred *cred;
1017
1018 if (fc->flags & FUSE_ALLOW_OTHER)
1019 return 1;
1020
1021 cred = current_cred();
1022 if (uid_eq(cred->euid, fc->user_id) &&
1023 uid_eq(cred->suid, fc->user_id) &&
1024 uid_eq(cred->uid, fc->user_id) &&
1025 gid_eq(cred->egid, fc->group_id) &&
1026 gid_eq(cred->sgid, fc->group_id) &&
1027 gid_eq(cred->gid, fc->group_id))
1028 return 1;
1029
1030 return 0;
1031 }
1032
1033 static int fuse_access(struct inode *inode, int mask)
1034 {
1035 struct fuse_conn *fc = get_fuse_conn(inode);
1036 FUSE_ARGS(args);
1037 struct fuse_access_in inarg;
1038 int err;
1039
1040 BUG_ON(mask & MAY_NOT_BLOCK);
1041
1042 if (fc->no_access)
1043 return 0;
1044
1045 memset(&inarg, 0, sizeof(inarg));
1046 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1047 args.in.h.opcode = FUSE_ACCESS;
1048 args.in.h.nodeid = get_node_id(inode);
1049 args.in.numargs = 1;
1050 args.in.args[0].size = sizeof(inarg);
1051 args.in.args[0].value = &inarg;
1052 err = fuse_simple_request(fc, &args);
1053 if (err == -ENOSYS) {
1054 fc->no_access = 1;
1055 err = 0;
1056 }
1057 return err;
1058 }
1059
1060 static int fuse_perm_getattr(struct inode *inode, int mask)
1061 {
1062 if (mask & MAY_NOT_BLOCK)
1063 return -ECHILD;
1064
1065 return fuse_do_getattr(inode, NULL, NULL);
1066 }
1067
1068 /*
1069 * Check permission. The two basic access models of FUSE are:
1070 *
1071 * 1) Local access checking ('default_permissions' mount option) based
1072 * on file mode. This is the plain old disk filesystem permission
1073 * modell.
1074 *
1075 * 2) "Remote" access checking, where server is responsible for
1076 * checking permission in each inode operation. An exception to this
1077 * is if ->permission() was invoked from sys_access() in which case an
1078 * access request is sent. Execute permission is still checked
1079 * locally based on file mode.
1080 */
1081 static int fuse_permission(struct inode *inode, int mask)
1082 {
1083 struct fuse_conn *fc = get_fuse_conn(inode);
1084 bool refreshed = false;
1085 int err = 0;
1086
1087 if (!fuse_allow_current_process(fc))
1088 return -EACCES;
1089
1090 /*
1091 * If attributes are needed, refresh them before proceeding
1092 */
1093 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1094 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1095 struct fuse_inode *fi = get_fuse_inode(inode);
1096
1097 if (time_before64(fi->i_time, get_jiffies_64())) {
1098 refreshed = true;
1099
1100 err = fuse_perm_getattr(inode, mask);
1101 if (err)
1102 return err;
1103 }
1104 }
1105
1106 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1107 err = generic_permission(inode, mask);
1108
1109 /* If permission is denied, try to refresh file
1110 attributes. This is also needed, because the root
1111 node will at first have no permissions */
1112 if (err == -EACCES && !refreshed) {
1113 err = fuse_perm_getattr(inode, mask);
1114 if (!err)
1115 err = generic_permission(inode, mask);
1116 }
1117
1118 /* Note: the opposite of the above test does not
1119 exist. So if permissions are revoked this won't be
1120 noticed immediately, only after the attribute
1121 timeout has expired */
1122 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1123 err = fuse_access(inode, mask);
1124 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1125 if (!(inode->i_mode & S_IXUGO)) {
1126 if (refreshed)
1127 return -EACCES;
1128
1129 err = fuse_perm_getattr(inode, mask);
1130 if (!err && !(inode->i_mode & S_IXUGO))
1131 return -EACCES;
1132 }
1133 }
1134 return err;
1135 }
1136
1137 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1138 struct dir_context *ctx)
1139 {
1140 while (nbytes >= FUSE_NAME_OFFSET) {
1141 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1142 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1143 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1144 return -EIO;
1145 if (reclen > nbytes)
1146 break;
1147 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1148 return -EIO;
1149
1150 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1151 dirent->ino, dirent->type))
1152 break;
1153
1154 buf += reclen;
1155 nbytes -= reclen;
1156 ctx->pos = dirent->off;
1157 }
1158
1159 return 0;
1160 }
1161
1162 static int fuse_direntplus_link(struct file *file,
1163 struct fuse_direntplus *direntplus,
1164 u64 attr_version)
1165 {
1166 struct fuse_entry_out *o = &direntplus->entry_out;
1167 struct fuse_dirent *dirent = &direntplus->dirent;
1168 struct dentry *parent = file->f_path.dentry;
1169 struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1170 struct dentry *dentry;
1171 struct dentry *alias;
1172 struct inode *dir = d_inode(parent);
1173 struct fuse_conn *fc;
1174 struct inode *inode;
1175 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1176
1177 if (!o->nodeid) {
1178 /*
1179 * Unlike in the case of fuse_lookup, zero nodeid does not mean
1180 * ENOENT. Instead, it only means the userspace filesystem did
1181 * not want to return attributes/handle for this entry.
1182 *
1183 * So do nothing.
1184 */
1185 return 0;
1186 }
1187
1188 if (name.name[0] == '.') {
1189 /*
1190 * We could potentially refresh the attributes of the directory
1191 * and its parent?
1192 */
1193 if (name.len == 1)
1194 return 0;
1195 if (name.name[1] == '.' && name.len == 2)
1196 return 0;
1197 }
1198
1199 if (invalid_nodeid(o->nodeid))
1200 return -EIO;
1201 if (!fuse_valid_type(o->attr.mode))
1202 return -EIO;
1203
1204 fc = get_fuse_conn(dir);
1205
1206 name.hash = full_name_hash(parent, name.name, name.len);
1207 dentry = d_lookup(parent, &name);
1208 if (!dentry) {
1209 retry:
1210 dentry = d_alloc_parallel(parent, &name, &wq);
1211 if (IS_ERR(dentry))
1212 return PTR_ERR(dentry);
1213 }
1214 if (!d_in_lookup(dentry)) {
1215 struct fuse_inode *fi;
1216 inode = d_inode(dentry);
1217 if (!inode ||
1218 get_node_id(inode) != o->nodeid ||
1219 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1220 d_invalidate(dentry);
1221 dput(dentry);
1222 goto retry;
1223 }
1224 if (is_bad_inode(inode)) {
1225 dput(dentry);
1226 return -EIO;
1227 }
1228
1229 fi = get_fuse_inode(inode);
1230 spin_lock(&fc->lock);
1231 fi->nlookup++;
1232 spin_unlock(&fc->lock);
1233
1234 fuse_change_attributes(inode, &o->attr,
1235 entry_attr_timeout(o),
1236 attr_version);
1237 /*
1238 * The other branch comes via fuse_iget()
1239 * which bumps nlookup inside
1240 */
1241 } else {
1242 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1243 &o->attr, entry_attr_timeout(o),
1244 attr_version);
1245 if (!inode)
1246 inode = ERR_PTR(-ENOMEM);
1247
1248 alias = d_splice_alias(inode, dentry);
1249 d_lookup_done(dentry);
1250 if (alias) {
1251 dput(dentry);
1252 dentry = alias;
1253 }
1254 if (IS_ERR(dentry))
1255 return PTR_ERR(dentry);
1256 }
1257 if (fc->readdirplus_auto)
1258 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1259 fuse_change_entry_timeout(dentry, o);
1260
1261 dput(dentry);
1262 return 0;
1263 }
1264
1265 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1266 struct dir_context *ctx, u64 attr_version)
1267 {
1268 struct fuse_direntplus *direntplus;
1269 struct fuse_dirent *dirent;
1270 size_t reclen;
1271 int over = 0;
1272 int ret;
1273
1274 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1275 direntplus = (struct fuse_direntplus *) buf;
1276 dirent = &direntplus->dirent;
1277 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1278
1279 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1280 return -EIO;
1281 if (reclen > nbytes)
1282 break;
1283 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1284 return -EIO;
1285
1286 if (!over) {
1287 /* We fill entries into dstbuf only as much as
1288 it can hold. But we still continue iterating
1289 over remaining entries to link them. If not,
1290 we need to send a FORGET for each of those
1291 which we did not link.
1292 */
1293 over = !dir_emit(ctx, dirent->name, dirent->namelen,
1294 dirent->ino, dirent->type);
1295 ctx->pos = dirent->off;
1296 }
1297
1298 buf += reclen;
1299 nbytes -= reclen;
1300
1301 ret = fuse_direntplus_link(file, direntplus, attr_version);
1302 if (ret)
1303 fuse_force_forget(file, direntplus->entry_out.nodeid);
1304 }
1305
1306 return 0;
1307 }
1308
1309 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1310 {
1311 int plus, err;
1312 size_t nbytes;
1313 struct page *page;
1314 struct inode *inode = file_inode(file);
1315 struct fuse_conn *fc = get_fuse_conn(inode);
1316 struct fuse_req *req;
1317 u64 attr_version = 0;
1318
1319 if (is_bad_inode(inode))
1320 return -EIO;
1321
1322 req = fuse_get_req(fc, 1);
1323 if (IS_ERR(req))
1324 return PTR_ERR(req);
1325
1326 page = alloc_page(GFP_KERNEL);
1327 if (!page) {
1328 fuse_put_request(fc, req);
1329 return -ENOMEM;
1330 }
1331
1332 plus = fuse_use_readdirplus(inode, ctx);
1333 req->out.argpages = 1;
1334 req->num_pages = 1;
1335 req->pages[0] = page;
1336 req->page_descs[0].length = PAGE_SIZE;
1337 if (plus) {
1338 attr_version = fuse_get_attr_version(fc);
1339 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1340 FUSE_READDIRPLUS);
1341 } else {
1342 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1343 FUSE_READDIR);
1344 }
1345 fuse_request_send(fc, req);
1346 nbytes = req->out.args[0].size;
1347 err = req->out.h.error;
1348 fuse_put_request(fc, req);
1349 if (!err) {
1350 if (plus) {
1351 err = parse_dirplusfile(page_address(page), nbytes,
1352 file, ctx,
1353 attr_version);
1354 } else {
1355 err = parse_dirfile(page_address(page), nbytes, file,
1356 ctx);
1357 }
1358 }
1359
1360 __free_page(page);
1361 fuse_invalidate_atime(inode);
1362 return err;
1363 }
1364
1365 static const char *fuse_get_link(struct dentry *dentry,
1366 struct inode *inode,
1367 struct delayed_call *done)
1368 {
1369 struct fuse_conn *fc = get_fuse_conn(inode);
1370 FUSE_ARGS(args);
1371 char *link;
1372 ssize_t ret;
1373
1374 if (!dentry)
1375 return ERR_PTR(-ECHILD);
1376
1377 link = kmalloc(PAGE_SIZE, GFP_KERNEL);
1378 if (!link)
1379 return ERR_PTR(-ENOMEM);
1380
1381 args.in.h.opcode = FUSE_READLINK;
1382 args.in.h.nodeid = get_node_id(inode);
1383 args.out.argvar = 1;
1384 args.out.numargs = 1;
1385 args.out.args[0].size = PAGE_SIZE - 1;
1386 args.out.args[0].value = link;
1387 ret = fuse_simple_request(fc, &args);
1388 if (ret < 0) {
1389 kfree(link);
1390 link = ERR_PTR(ret);
1391 } else {
1392 link[ret] = '\0';
1393 set_delayed_call(done, kfree_link, link);
1394 }
1395 fuse_invalidate_atime(inode);
1396 return link;
1397 }
1398
1399 static int fuse_dir_open(struct inode *inode, struct file *file)
1400 {
1401 return fuse_open_common(inode, file, true);
1402 }
1403
1404 static int fuse_dir_release(struct inode *inode, struct file *file)
1405 {
1406 fuse_release_common(file, FUSE_RELEASEDIR);
1407
1408 return 0;
1409 }
1410
1411 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1412 int datasync)
1413 {
1414 return fuse_fsync_common(file, start, end, datasync, 1);
1415 }
1416
1417 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1418 unsigned long arg)
1419 {
1420 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1421
1422 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1423 if (fc->minor < 18)
1424 return -ENOTTY;
1425
1426 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1427 }
1428
1429 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1430 unsigned long arg)
1431 {
1432 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1433
1434 if (fc->minor < 18)
1435 return -ENOTTY;
1436
1437 return fuse_ioctl_common(file, cmd, arg,
1438 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1439 }
1440
1441 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1442 {
1443 /* Always update if mtime is explicitly set */
1444 if (ivalid & ATTR_MTIME_SET)
1445 return true;
1446
1447 /* Or if kernel i_mtime is the official one */
1448 if (trust_local_mtime)
1449 return true;
1450
1451 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1452 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1453 return false;
1454
1455 /* In all other cases update */
1456 return true;
1457 }
1458
1459 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg,
1460 bool trust_local_cmtime)
1461 {
1462 unsigned ivalid = iattr->ia_valid;
1463
1464 if (ivalid & ATTR_MODE)
1465 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1466 if (ivalid & ATTR_UID)
1467 arg->valid |= FATTR_UID, arg->uid = from_kuid(&init_user_ns, iattr->ia_uid);
1468 if (ivalid & ATTR_GID)
1469 arg->valid |= FATTR_GID, arg->gid = from_kgid(&init_user_ns, iattr->ia_gid);
1470 if (ivalid & ATTR_SIZE)
1471 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1472 if (ivalid & ATTR_ATIME) {
1473 arg->valid |= FATTR_ATIME;
1474 arg->atime = iattr->ia_atime.tv_sec;
1475 arg->atimensec = iattr->ia_atime.tv_nsec;
1476 if (!(ivalid & ATTR_ATIME_SET))
1477 arg->valid |= FATTR_ATIME_NOW;
1478 }
1479 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1480 arg->valid |= FATTR_MTIME;
1481 arg->mtime = iattr->ia_mtime.tv_sec;
1482 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1483 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1484 arg->valid |= FATTR_MTIME_NOW;
1485 }
1486 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1487 arg->valid |= FATTR_CTIME;
1488 arg->ctime = iattr->ia_ctime.tv_sec;
1489 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1490 }
1491 }
1492
1493 /*
1494 * Prevent concurrent writepages on inode
1495 *
1496 * This is done by adding a negative bias to the inode write counter
1497 * and waiting for all pending writes to finish.
1498 */
1499 void fuse_set_nowrite(struct inode *inode)
1500 {
1501 struct fuse_conn *fc = get_fuse_conn(inode);
1502 struct fuse_inode *fi = get_fuse_inode(inode);
1503
1504 BUG_ON(!inode_is_locked(inode));
1505
1506 spin_lock(&fc->lock);
1507 BUG_ON(fi->writectr < 0);
1508 fi->writectr += FUSE_NOWRITE;
1509 spin_unlock(&fc->lock);
1510 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1511 }
1512
1513 /*
1514 * Allow writepages on inode
1515 *
1516 * Remove the bias from the writecounter and send any queued
1517 * writepages.
1518 */
1519 static void __fuse_release_nowrite(struct inode *inode)
1520 {
1521 struct fuse_inode *fi = get_fuse_inode(inode);
1522
1523 BUG_ON(fi->writectr != FUSE_NOWRITE);
1524 fi->writectr = 0;
1525 fuse_flush_writepages(inode);
1526 }
1527
1528 void fuse_release_nowrite(struct inode *inode)
1529 {
1530 struct fuse_conn *fc = get_fuse_conn(inode);
1531
1532 spin_lock(&fc->lock);
1533 __fuse_release_nowrite(inode);
1534 spin_unlock(&fc->lock);
1535 }
1536
1537 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1538 struct inode *inode,
1539 struct fuse_setattr_in *inarg_p,
1540 struct fuse_attr_out *outarg_p)
1541 {
1542 args->in.h.opcode = FUSE_SETATTR;
1543 args->in.h.nodeid = get_node_id(inode);
1544 args->in.numargs = 1;
1545 args->in.args[0].size = sizeof(*inarg_p);
1546 args->in.args[0].value = inarg_p;
1547 args->out.numargs = 1;
1548 args->out.args[0].size = sizeof(*outarg_p);
1549 args->out.args[0].value = outarg_p;
1550 }
1551
1552 /*
1553 * Flush inode->i_mtime to the server
1554 */
1555 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1556 {
1557 struct fuse_conn *fc = get_fuse_conn(inode);
1558 FUSE_ARGS(args);
1559 struct fuse_setattr_in inarg;
1560 struct fuse_attr_out outarg;
1561
1562 memset(&inarg, 0, sizeof(inarg));
1563 memset(&outarg, 0, sizeof(outarg));
1564
1565 inarg.valid = FATTR_MTIME;
1566 inarg.mtime = inode->i_mtime.tv_sec;
1567 inarg.mtimensec = inode->i_mtime.tv_nsec;
1568 if (fc->minor >= 23) {
1569 inarg.valid |= FATTR_CTIME;
1570 inarg.ctime = inode->i_ctime.tv_sec;
1571 inarg.ctimensec = inode->i_ctime.tv_nsec;
1572 }
1573 if (ff) {
1574 inarg.valid |= FATTR_FH;
1575 inarg.fh = ff->fh;
1576 }
1577 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1578
1579 return fuse_simple_request(fc, &args);
1580 }
1581
1582 /*
1583 * Set attributes, and at the same time refresh them.
1584 *
1585 * Truncation is slightly complicated, because the 'truncate' request
1586 * may fail, in which case we don't want to touch the mapping.
1587 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1588 * and the actual truncation by hand.
1589 */
1590 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
1591 struct file *file)
1592 {
1593 struct fuse_conn *fc = get_fuse_conn(inode);
1594 struct fuse_inode *fi = get_fuse_inode(inode);
1595 FUSE_ARGS(args);
1596 struct fuse_setattr_in inarg;
1597 struct fuse_attr_out outarg;
1598 bool is_truncate = false;
1599 bool is_wb = fc->writeback_cache;
1600 loff_t oldsize;
1601 int err;
1602 bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1603
1604 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1605 attr->ia_valid |= ATTR_FORCE;
1606
1607 err = inode_change_ok(inode, attr);
1608 if (err)
1609 return err;
1610
1611 if (attr->ia_valid & ATTR_OPEN) {
1612 if (fc->atomic_o_trunc)
1613 return 0;
1614 file = NULL;
1615 }
1616
1617 if (attr->ia_valid & ATTR_SIZE)
1618 is_truncate = true;
1619
1620 if (is_truncate) {
1621 fuse_set_nowrite(inode);
1622 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1623 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1624 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1625 }
1626
1627 memset(&inarg, 0, sizeof(inarg));
1628 memset(&outarg, 0, sizeof(outarg));
1629 iattr_to_fattr(attr, &inarg, trust_local_cmtime);
1630 if (file) {
1631 struct fuse_file *ff = file->private_data;
1632 inarg.valid |= FATTR_FH;
1633 inarg.fh = ff->fh;
1634 }
1635 if (attr->ia_valid & ATTR_SIZE) {
1636 /* For mandatory locking in truncate */
1637 inarg.valid |= FATTR_LOCKOWNER;
1638 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1639 }
1640 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1641 err = fuse_simple_request(fc, &args);
1642 if (err) {
1643 if (err == -EINTR)
1644 fuse_invalidate_attr(inode);
1645 goto error;
1646 }
1647
1648 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1649 make_bad_inode(inode);
1650 err = -EIO;
1651 goto error;
1652 }
1653
1654 spin_lock(&fc->lock);
1655 /* the kernel maintains i_mtime locally */
1656 if (trust_local_cmtime) {
1657 if (attr->ia_valid & ATTR_MTIME)
1658 inode->i_mtime = attr->ia_mtime;
1659 if (attr->ia_valid & ATTR_CTIME)
1660 inode->i_ctime = attr->ia_ctime;
1661 /* FIXME: clear I_DIRTY_SYNC? */
1662 }
1663
1664 fuse_change_attributes_common(inode, &outarg.attr,
1665 attr_timeout(&outarg));
1666 oldsize = inode->i_size;
1667 /* see the comment in fuse_change_attributes() */
1668 if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1669 i_size_write(inode, outarg.attr.size);
1670
1671 if (is_truncate) {
1672 /* NOTE: this may release/reacquire fc->lock */
1673 __fuse_release_nowrite(inode);
1674 }
1675 spin_unlock(&fc->lock);
1676
1677 /*
1678 * Only call invalidate_inode_pages2() after removing
1679 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1680 */
1681 if ((is_truncate || !is_wb) &&
1682 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1683 truncate_pagecache(inode, outarg.attr.size);
1684 invalidate_inode_pages2(inode->i_mapping);
1685 }
1686
1687 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1688 return 0;
1689
1690 error:
1691 if (is_truncate)
1692 fuse_release_nowrite(inode);
1693
1694 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1695 return err;
1696 }
1697
1698 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1699 {
1700 struct inode *inode = d_inode(entry);
1701
1702 if (!fuse_allow_current_process(get_fuse_conn(inode)))
1703 return -EACCES;
1704
1705 if (attr->ia_valid & ATTR_FILE)
1706 return fuse_do_setattr(inode, attr, attr->ia_file);
1707 else
1708 return fuse_do_setattr(inode, attr, NULL);
1709 }
1710
1711 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1712 struct kstat *stat)
1713 {
1714 struct inode *inode = d_inode(entry);
1715 struct fuse_conn *fc = get_fuse_conn(inode);
1716
1717 if (!fuse_allow_current_process(fc))
1718 return -EACCES;
1719
1720 return fuse_update_attributes(inode, stat, NULL, NULL);
1721 }
1722
1723 static int fuse_setxattr(struct dentry *unused, struct inode *inode,
1724 const char *name, const void *value,
1725 size_t size, int flags)
1726 {
1727 struct fuse_conn *fc = get_fuse_conn(inode);
1728 FUSE_ARGS(args);
1729 struct fuse_setxattr_in inarg;
1730 int err;
1731
1732 if (fc->no_setxattr)
1733 return -EOPNOTSUPP;
1734
1735 memset(&inarg, 0, sizeof(inarg));
1736 inarg.size = size;
1737 inarg.flags = flags;
1738 args.in.h.opcode = FUSE_SETXATTR;
1739 args.in.h.nodeid = get_node_id(inode);
1740 args.in.numargs = 3;
1741 args.in.args[0].size = sizeof(inarg);
1742 args.in.args[0].value = &inarg;
1743 args.in.args[1].size = strlen(name) + 1;
1744 args.in.args[1].value = name;
1745 args.in.args[2].size = size;
1746 args.in.args[2].value = value;
1747 err = fuse_simple_request(fc, &args);
1748 if (err == -ENOSYS) {
1749 fc->no_setxattr = 1;
1750 err = -EOPNOTSUPP;
1751 }
1752 if (!err) {
1753 fuse_invalidate_attr(inode);
1754 fuse_update_ctime(inode);
1755 }
1756 return err;
1757 }
1758
1759 static ssize_t fuse_getxattr(struct dentry *entry, struct inode *inode,
1760 const char *name, void *value, size_t size)
1761 {
1762 struct fuse_conn *fc = get_fuse_conn(inode);
1763 FUSE_ARGS(args);
1764 struct fuse_getxattr_in inarg;
1765 struct fuse_getxattr_out outarg;
1766 ssize_t ret;
1767
1768 if (fc->no_getxattr)
1769 return -EOPNOTSUPP;
1770
1771 memset(&inarg, 0, sizeof(inarg));
1772 inarg.size = size;
1773 args.in.h.opcode = FUSE_GETXATTR;
1774 args.in.h.nodeid = get_node_id(inode);
1775 args.in.numargs = 2;
1776 args.in.args[0].size = sizeof(inarg);
1777 args.in.args[0].value = &inarg;
1778 args.in.args[1].size = strlen(name) + 1;
1779 args.in.args[1].value = name;
1780 /* This is really two different operations rolled into one */
1781 args.out.numargs = 1;
1782 if (size) {
1783 args.out.argvar = 1;
1784 args.out.args[0].size = size;
1785 args.out.args[0].value = value;
1786 } else {
1787 args.out.args[0].size = sizeof(outarg);
1788 args.out.args[0].value = &outarg;
1789 }
1790 ret = fuse_simple_request(fc, &args);
1791 if (!ret && !size)
1792 ret = outarg.size;
1793 if (ret == -ENOSYS) {
1794 fc->no_getxattr = 1;
1795 ret = -EOPNOTSUPP;
1796 }
1797 return ret;
1798 }
1799
1800 static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
1801 {
1802 struct inode *inode = d_inode(entry);
1803 struct fuse_conn *fc = get_fuse_conn(inode);
1804 FUSE_ARGS(args);
1805 struct fuse_getxattr_in inarg;
1806 struct fuse_getxattr_out outarg;
1807 ssize_t ret;
1808
1809 if (!fuse_allow_current_process(fc))
1810 return -EACCES;
1811
1812 if (fc->no_listxattr)
1813 return -EOPNOTSUPP;
1814
1815 memset(&inarg, 0, sizeof(inarg));
1816 inarg.size = size;
1817 args.in.h.opcode = FUSE_LISTXATTR;
1818 args.in.h.nodeid = get_node_id(inode);
1819 args.in.numargs = 1;
1820 args.in.args[0].size = sizeof(inarg);
1821 args.in.args[0].value = &inarg;
1822 /* This is really two different operations rolled into one */
1823 args.out.numargs = 1;
1824 if (size) {
1825 args.out.argvar = 1;
1826 args.out.args[0].size = size;
1827 args.out.args[0].value = list;
1828 } else {
1829 args.out.args[0].size = sizeof(outarg);
1830 args.out.args[0].value = &outarg;
1831 }
1832 ret = fuse_simple_request(fc, &args);
1833 if (!ret && !size)
1834 ret = outarg.size;
1835 if (ret == -ENOSYS) {
1836 fc->no_listxattr = 1;
1837 ret = -EOPNOTSUPP;
1838 }
1839 return ret;
1840 }
1841
1842 static int fuse_removexattr(struct dentry *entry, const char *name)
1843 {
1844 struct inode *inode = d_inode(entry);
1845 struct fuse_conn *fc = get_fuse_conn(inode);
1846 FUSE_ARGS(args);
1847 int err;
1848
1849 if (fc->no_removexattr)
1850 return -EOPNOTSUPP;
1851
1852 args.in.h.opcode = FUSE_REMOVEXATTR;
1853 args.in.h.nodeid = get_node_id(inode);
1854 args.in.numargs = 1;
1855 args.in.args[0].size = strlen(name) + 1;
1856 args.in.args[0].value = name;
1857 err = fuse_simple_request(fc, &args);
1858 if (err == -ENOSYS) {
1859 fc->no_removexattr = 1;
1860 err = -EOPNOTSUPP;
1861 }
1862 if (!err) {
1863 fuse_invalidate_attr(inode);
1864 fuse_update_ctime(inode);
1865 }
1866 return err;
1867 }
1868
1869 static const struct inode_operations fuse_dir_inode_operations = {
1870 .lookup = fuse_lookup,
1871 .mkdir = fuse_mkdir,
1872 .symlink = fuse_symlink,
1873 .unlink = fuse_unlink,
1874 .rmdir = fuse_rmdir,
1875 .rename2 = fuse_rename2,
1876 .link = fuse_link,
1877 .setattr = fuse_setattr,
1878 .create = fuse_create,
1879 .atomic_open = fuse_atomic_open,
1880 .mknod = fuse_mknod,
1881 .permission = fuse_permission,
1882 .getattr = fuse_getattr,
1883 .setxattr = fuse_setxattr,
1884 .getxattr = fuse_getxattr,
1885 .listxattr = fuse_listxattr,
1886 .removexattr = fuse_removexattr,
1887 };
1888
1889 static const struct file_operations fuse_dir_operations = {
1890 .llseek = generic_file_llseek,
1891 .read = generic_read_dir,
1892 .iterate_shared = fuse_readdir,
1893 .open = fuse_dir_open,
1894 .release = fuse_dir_release,
1895 .fsync = fuse_dir_fsync,
1896 .unlocked_ioctl = fuse_dir_ioctl,
1897 .compat_ioctl = fuse_dir_compat_ioctl,
1898 };
1899
1900 static const struct inode_operations fuse_common_inode_operations = {
1901 .setattr = fuse_setattr,
1902 .permission = fuse_permission,
1903 .getattr = fuse_getattr,
1904 .setxattr = fuse_setxattr,
1905 .getxattr = fuse_getxattr,
1906 .listxattr = fuse_listxattr,
1907 .removexattr = fuse_removexattr,
1908 };
1909
1910 static const struct inode_operations fuse_symlink_inode_operations = {
1911 .setattr = fuse_setattr,
1912 .get_link = fuse_get_link,
1913 .readlink = generic_readlink,
1914 .getattr = fuse_getattr,
1915 .setxattr = fuse_setxattr,
1916 .getxattr = fuse_getxattr,
1917 .listxattr = fuse_listxattr,
1918 .removexattr = fuse_removexattr,
1919 };
1920
1921 void fuse_init_common(struct inode *inode)
1922 {
1923 inode->i_op = &fuse_common_inode_operations;
1924 }
1925
1926 void fuse_init_dir(struct inode *inode)
1927 {
1928 inode->i_op = &fuse_dir_inode_operations;
1929 inode->i_fop = &fuse_dir_operations;
1930 }
1931
1932 void fuse_init_symlink(struct inode *inode)
1933 {
1934 inode->i_op = &fuse_symlink_inode_operations;
1935 }
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