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[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
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 mutex_lock(&parent->i_mutex);
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 entry = d_lookup(dir, name);
957 dput(dir);
958 if (!entry)
959 goto unlock;
960
961 fuse_invalidate_attr(parent);
962 fuse_invalidate_entry(entry);
963
964 if (child_nodeid != 0 && d_really_is_positive(entry)) {
965 mutex_lock(&d_inode(entry)->i_mutex);
966 if (get_node_id(d_inode(entry)) != child_nodeid) {
967 err = -ENOENT;
968 goto badentry;
969 }
970 if (d_mountpoint(entry)) {
971 err = -EBUSY;
972 goto badentry;
973 }
974 if (d_is_dir(entry)) {
975 shrink_dcache_parent(entry);
976 if (!simple_empty(entry)) {
977 err = -ENOTEMPTY;
978 goto badentry;
979 }
980 d_inode(entry)->i_flags |= S_DEAD;
981 }
982 dont_mount(entry);
983 clear_nlink(d_inode(entry));
984 err = 0;
985 badentry:
986 mutex_unlock(&d_inode(entry)->i_mutex);
987 if (!err)
988 d_delete(entry);
989 } else {
990 err = 0;
991 }
992 dput(entry);
993
994 unlock:
995 mutex_unlock(&parent->i_mutex);
996 iput(parent);
997 return err;
998 }
999
1000 /*
1001 * Calling into a user-controlled filesystem gives the filesystem
1002 * daemon ptrace-like capabilities over the current process. This
1003 * means, that the filesystem daemon is able to record the exact
1004 * filesystem operations performed, and can also control the behavior
1005 * of the requester process in otherwise impossible ways. For example
1006 * it can delay the operation for arbitrary length of time allowing
1007 * DoS against the requester.
1008 *
1009 * For this reason only those processes can call into the filesystem,
1010 * for which the owner of the mount has ptrace privilege. This
1011 * excludes processes started by other users, suid or sgid processes.
1012 */
1013 int fuse_allow_current_process(struct fuse_conn *fc)
1014 {
1015 const struct cred *cred;
1016
1017 if (fc->flags & FUSE_ALLOW_OTHER)
1018 return 1;
1019
1020 cred = current_cred();
1021 if (uid_eq(cred->euid, fc->user_id) &&
1022 uid_eq(cred->suid, fc->user_id) &&
1023 uid_eq(cred->uid, fc->user_id) &&
1024 gid_eq(cred->egid, fc->group_id) &&
1025 gid_eq(cred->sgid, fc->group_id) &&
1026 gid_eq(cred->gid, fc->group_id))
1027 return 1;
1028
1029 return 0;
1030 }
1031
1032 static int fuse_access(struct inode *inode, int mask)
1033 {
1034 struct fuse_conn *fc = get_fuse_conn(inode);
1035 FUSE_ARGS(args);
1036 struct fuse_access_in inarg;
1037 int err;
1038
1039 BUG_ON(mask & MAY_NOT_BLOCK);
1040
1041 if (fc->no_access)
1042 return 0;
1043
1044 memset(&inarg, 0, sizeof(inarg));
1045 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1046 args.in.h.opcode = FUSE_ACCESS;
1047 args.in.h.nodeid = get_node_id(inode);
1048 args.in.numargs = 1;
1049 args.in.args[0].size = sizeof(inarg);
1050 args.in.args[0].value = &inarg;
1051 err = fuse_simple_request(fc, &args);
1052 if (err == -ENOSYS) {
1053 fc->no_access = 1;
1054 err = 0;
1055 }
1056 return err;
1057 }
1058
1059 static int fuse_perm_getattr(struct inode *inode, int mask)
1060 {
1061 if (mask & MAY_NOT_BLOCK)
1062 return -ECHILD;
1063
1064 return fuse_do_getattr(inode, NULL, NULL);
1065 }
1066
1067 /*
1068 * Check permission. The two basic access models of FUSE are:
1069 *
1070 * 1) Local access checking ('default_permissions' mount option) based
1071 * on file mode. This is the plain old disk filesystem permission
1072 * modell.
1073 *
1074 * 2) "Remote" access checking, where server is responsible for
1075 * checking permission in each inode operation. An exception to this
1076 * is if ->permission() was invoked from sys_access() in which case an
1077 * access request is sent. Execute permission is still checked
1078 * locally based on file mode.
1079 */
1080 static int fuse_permission(struct inode *inode, int mask)
1081 {
1082 struct fuse_conn *fc = get_fuse_conn(inode);
1083 bool refreshed = false;
1084 int err = 0;
1085
1086 if (!fuse_allow_current_process(fc))
1087 return -EACCES;
1088
1089 /*
1090 * If attributes are needed, refresh them before proceeding
1091 */
1092 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1093 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1094 struct fuse_inode *fi = get_fuse_inode(inode);
1095
1096 if (time_before64(fi->i_time, get_jiffies_64())) {
1097 refreshed = true;
1098
1099 err = fuse_perm_getattr(inode, mask);
1100 if (err)
1101 return err;
1102 }
1103 }
1104
1105 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1106 err = generic_permission(inode, mask);
1107
1108 /* If permission is denied, try to refresh file
1109 attributes. This is also needed, because the root
1110 node will at first have no permissions */
1111 if (err == -EACCES && !refreshed) {
1112 err = fuse_perm_getattr(inode, mask);
1113 if (!err)
1114 err = generic_permission(inode, mask);
1115 }
1116
1117 /* Note: the opposite of the above test does not
1118 exist. So if permissions are revoked this won't be
1119 noticed immediately, only after the attribute
1120 timeout has expired */
1121 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1122 err = fuse_access(inode, mask);
1123 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1124 if (!(inode->i_mode & S_IXUGO)) {
1125 if (refreshed)
1126 return -EACCES;
1127
1128 err = fuse_perm_getattr(inode, mask);
1129 if (!err && !(inode->i_mode & S_IXUGO))
1130 return -EACCES;
1131 }
1132 }
1133 return err;
1134 }
1135
1136 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1137 struct dir_context *ctx)
1138 {
1139 while (nbytes >= FUSE_NAME_OFFSET) {
1140 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1141 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1142 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1143 return -EIO;
1144 if (reclen > nbytes)
1145 break;
1146 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1147 return -EIO;
1148
1149 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1150 dirent->ino, dirent->type))
1151 break;
1152
1153 buf += reclen;
1154 nbytes -= reclen;
1155 ctx->pos = dirent->off;
1156 }
1157
1158 return 0;
1159 }
1160
1161 static int fuse_direntplus_link(struct file *file,
1162 struct fuse_direntplus *direntplus,
1163 u64 attr_version)
1164 {
1165 int err;
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
1176 if (!o->nodeid) {
1177 /*
1178 * Unlike in the case of fuse_lookup, zero nodeid does not mean
1179 * ENOENT. Instead, it only means the userspace filesystem did
1180 * not want to return attributes/handle for this entry.
1181 *
1182 * So do nothing.
1183 */
1184 return 0;
1185 }
1186
1187 if (name.name[0] == '.') {
1188 /*
1189 * We could potentially refresh the attributes of the directory
1190 * and its parent?
1191 */
1192 if (name.len == 1)
1193 return 0;
1194 if (name.name[1] == '.' && name.len == 2)
1195 return 0;
1196 }
1197
1198 if (invalid_nodeid(o->nodeid))
1199 return -EIO;
1200 if (!fuse_valid_type(o->attr.mode))
1201 return -EIO;
1202
1203 fc = get_fuse_conn(dir);
1204
1205 name.hash = full_name_hash(name.name, name.len);
1206 dentry = d_lookup(parent, &name);
1207 if (dentry) {
1208 inode = d_inode(dentry);
1209 if (!inode) {
1210 d_drop(dentry);
1211 } else if (get_node_id(inode) != o->nodeid ||
1212 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1213 d_invalidate(dentry);
1214 } else if (is_bad_inode(inode)) {
1215 err = -EIO;
1216 goto out;
1217 } else {
1218 struct fuse_inode *fi;
1219 fi = get_fuse_inode(inode);
1220 spin_lock(&fc->lock);
1221 fi->nlookup++;
1222 spin_unlock(&fc->lock);
1223
1224 fuse_change_attributes(inode, &o->attr,
1225 entry_attr_timeout(o),
1226 attr_version);
1227
1228 /*
1229 * The other branch to 'found' comes via fuse_iget()
1230 * which bumps nlookup inside
1231 */
1232 goto found;
1233 }
1234 dput(dentry);
1235 }
1236
1237 dentry = d_alloc(parent, &name);
1238 err = -ENOMEM;
1239 if (!dentry)
1240 goto out;
1241
1242 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1243 &o->attr, entry_attr_timeout(o), attr_version);
1244 if (!inode)
1245 goto out;
1246
1247 alias = d_splice_alias(inode, dentry);
1248 err = PTR_ERR(alias);
1249 if (IS_ERR(alias))
1250 goto out;
1251
1252 if (alias) {
1253 dput(dentry);
1254 dentry = alias;
1255 }
1256
1257 found:
1258 if (fc->readdirplus_auto)
1259 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1260 fuse_change_entry_timeout(dentry, o);
1261
1262 err = 0;
1263 out:
1264 dput(dentry);
1265 return err;
1266 }
1267
1268 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1269 struct dir_context *ctx, u64 attr_version)
1270 {
1271 struct fuse_direntplus *direntplus;
1272 struct fuse_dirent *dirent;
1273 size_t reclen;
1274 int over = 0;
1275 int ret;
1276
1277 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1278 direntplus = (struct fuse_direntplus *) buf;
1279 dirent = &direntplus->dirent;
1280 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1281
1282 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1283 return -EIO;
1284 if (reclen > nbytes)
1285 break;
1286 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1287 return -EIO;
1288
1289 if (!over) {
1290 /* We fill entries into dstbuf only as much as
1291 it can hold. But we still continue iterating
1292 over remaining entries to link them. If not,
1293 we need to send a FORGET for each of those
1294 which we did not link.
1295 */
1296 over = !dir_emit(ctx, dirent->name, dirent->namelen,
1297 dirent->ino, dirent->type);
1298 ctx->pos = dirent->off;
1299 }
1300
1301 buf += reclen;
1302 nbytes -= reclen;
1303
1304 ret = fuse_direntplus_link(file, direntplus, attr_version);
1305 if (ret)
1306 fuse_force_forget(file, direntplus->entry_out.nodeid);
1307 }
1308
1309 return 0;
1310 }
1311
1312 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1313 {
1314 int plus, err;
1315 size_t nbytes;
1316 struct page *page;
1317 struct inode *inode = file_inode(file);
1318 struct fuse_conn *fc = get_fuse_conn(inode);
1319 struct fuse_req *req;
1320 u64 attr_version = 0;
1321
1322 if (is_bad_inode(inode))
1323 return -EIO;
1324
1325 req = fuse_get_req(fc, 1);
1326 if (IS_ERR(req))
1327 return PTR_ERR(req);
1328
1329 page = alloc_page(GFP_KERNEL);
1330 if (!page) {
1331 fuse_put_request(fc, req);
1332 return -ENOMEM;
1333 }
1334
1335 plus = fuse_use_readdirplus(inode, ctx);
1336 req->out.argpages = 1;
1337 req->num_pages = 1;
1338 req->pages[0] = page;
1339 req->page_descs[0].length = PAGE_SIZE;
1340 if (plus) {
1341 attr_version = fuse_get_attr_version(fc);
1342 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1343 FUSE_READDIRPLUS);
1344 } else {
1345 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1346 FUSE_READDIR);
1347 }
1348 fuse_request_send(fc, req);
1349 nbytes = req->out.args[0].size;
1350 err = req->out.h.error;
1351 fuse_put_request(fc, req);
1352 if (!err) {
1353 if (plus) {
1354 err = parse_dirplusfile(page_address(page), nbytes,
1355 file, ctx,
1356 attr_version);
1357 } else {
1358 err = parse_dirfile(page_address(page), nbytes, file,
1359 ctx);
1360 }
1361 }
1362
1363 __free_page(page);
1364 fuse_invalidate_atime(inode);
1365 return err;
1366 }
1367
1368 static const char *fuse_follow_link(struct dentry *dentry, void **cookie)
1369 {
1370 struct inode *inode = d_inode(dentry);
1371 struct fuse_conn *fc = get_fuse_conn(inode);
1372 FUSE_ARGS(args);
1373 char *link;
1374 ssize_t ret;
1375
1376 link = (char *) __get_free_page(GFP_KERNEL);
1377 if (!link)
1378 return ERR_PTR(-ENOMEM);
1379
1380 args.in.h.opcode = FUSE_READLINK;
1381 args.in.h.nodeid = get_node_id(inode);
1382 args.out.argvar = 1;
1383 args.out.numargs = 1;
1384 args.out.args[0].size = PAGE_SIZE - 1;
1385 args.out.args[0].value = link;
1386 ret = fuse_simple_request(fc, &args);
1387 if (ret < 0) {
1388 free_page((unsigned long) link);
1389 link = ERR_PTR(ret);
1390 } else {
1391 link[ret] = '\0';
1392 *cookie = link;
1393 }
1394 fuse_invalidate_atime(inode);
1395 return link;
1396 }
1397
1398 static int fuse_dir_open(struct inode *inode, struct file *file)
1399 {
1400 return fuse_open_common(inode, file, true);
1401 }
1402
1403 static int fuse_dir_release(struct inode *inode, struct file *file)
1404 {
1405 fuse_release_common(file, FUSE_RELEASEDIR);
1406
1407 return 0;
1408 }
1409
1410 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1411 int datasync)
1412 {
1413 return fuse_fsync_common(file, start, end, datasync, 1);
1414 }
1415
1416 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1417 unsigned long arg)
1418 {
1419 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1420
1421 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1422 if (fc->minor < 18)
1423 return -ENOTTY;
1424
1425 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1426 }
1427
1428 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1429 unsigned long arg)
1430 {
1431 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1432
1433 if (fc->minor < 18)
1434 return -ENOTTY;
1435
1436 return fuse_ioctl_common(file, cmd, arg,
1437 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1438 }
1439
1440 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1441 {
1442 /* Always update if mtime is explicitly set */
1443 if (ivalid & ATTR_MTIME_SET)
1444 return true;
1445
1446 /* Or if kernel i_mtime is the official one */
1447 if (trust_local_mtime)
1448 return true;
1449
1450 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1451 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1452 return false;
1453
1454 /* In all other cases update */
1455 return true;
1456 }
1457
1458 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg,
1459 bool trust_local_cmtime)
1460 {
1461 unsigned ivalid = iattr->ia_valid;
1462
1463 if (ivalid & ATTR_MODE)
1464 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1465 if (ivalid & ATTR_UID)
1466 arg->valid |= FATTR_UID, arg->uid = from_kuid(&init_user_ns, iattr->ia_uid);
1467 if (ivalid & ATTR_GID)
1468 arg->valid |= FATTR_GID, arg->gid = from_kgid(&init_user_ns, iattr->ia_gid);
1469 if (ivalid & ATTR_SIZE)
1470 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1471 if (ivalid & ATTR_ATIME) {
1472 arg->valid |= FATTR_ATIME;
1473 arg->atime = iattr->ia_atime.tv_sec;
1474 arg->atimensec = iattr->ia_atime.tv_nsec;
1475 if (!(ivalid & ATTR_ATIME_SET))
1476 arg->valid |= FATTR_ATIME_NOW;
1477 }
1478 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1479 arg->valid |= FATTR_MTIME;
1480 arg->mtime = iattr->ia_mtime.tv_sec;
1481 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1482 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1483 arg->valid |= FATTR_MTIME_NOW;
1484 }
1485 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1486 arg->valid |= FATTR_CTIME;
1487 arg->ctime = iattr->ia_ctime.tv_sec;
1488 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1489 }
1490 }
1491
1492 /*
1493 * Prevent concurrent writepages on inode
1494 *
1495 * This is done by adding a negative bias to the inode write counter
1496 * and waiting for all pending writes to finish.
1497 */
1498 void fuse_set_nowrite(struct inode *inode)
1499 {
1500 struct fuse_conn *fc = get_fuse_conn(inode);
1501 struct fuse_inode *fi = get_fuse_inode(inode);
1502
1503 BUG_ON(!mutex_is_locked(&inode->i_mutex));
1504
1505 spin_lock(&fc->lock);
1506 BUG_ON(fi->writectr < 0);
1507 fi->writectr += FUSE_NOWRITE;
1508 spin_unlock(&fc->lock);
1509 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1510 }
1511
1512 /*
1513 * Allow writepages on inode
1514 *
1515 * Remove the bias from the writecounter and send any queued
1516 * writepages.
1517 */
1518 static void __fuse_release_nowrite(struct inode *inode)
1519 {
1520 struct fuse_inode *fi = get_fuse_inode(inode);
1521
1522 BUG_ON(fi->writectr != FUSE_NOWRITE);
1523 fi->writectr = 0;
1524 fuse_flush_writepages(inode);
1525 }
1526
1527 void fuse_release_nowrite(struct inode *inode)
1528 {
1529 struct fuse_conn *fc = get_fuse_conn(inode);
1530
1531 spin_lock(&fc->lock);
1532 __fuse_release_nowrite(inode);
1533 spin_unlock(&fc->lock);
1534 }
1535
1536 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1537 struct inode *inode,
1538 struct fuse_setattr_in *inarg_p,
1539 struct fuse_attr_out *outarg_p)
1540 {
1541 args->in.h.opcode = FUSE_SETATTR;
1542 args->in.h.nodeid = get_node_id(inode);
1543 args->in.numargs = 1;
1544 args->in.args[0].size = sizeof(*inarg_p);
1545 args->in.args[0].value = inarg_p;
1546 args->out.numargs = 1;
1547 args->out.args[0].size = sizeof(*outarg_p);
1548 args->out.args[0].value = outarg_p;
1549 }
1550
1551 /*
1552 * Flush inode->i_mtime to the server
1553 */
1554 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1555 {
1556 struct fuse_conn *fc = get_fuse_conn(inode);
1557 FUSE_ARGS(args);
1558 struct fuse_setattr_in inarg;
1559 struct fuse_attr_out outarg;
1560
1561 memset(&inarg, 0, sizeof(inarg));
1562 memset(&outarg, 0, sizeof(outarg));
1563
1564 inarg.valid = FATTR_MTIME;
1565 inarg.mtime = inode->i_mtime.tv_sec;
1566 inarg.mtimensec = inode->i_mtime.tv_nsec;
1567 if (fc->minor >= 23) {
1568 inarg.valid |= FATTR_CTIME;
1569 inarg.ctime = inode->i_ctime.tv_sec;
1570 inarg.ctimensec = inode->i_ctime.tv_nsec;
1571 }
1572 if (ff) {
1573 inarg.valid |= FATTR_FH;
1574 inarg.fh = ff->fh;
1575 }
1576 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1577
1578 return fuse_simple_request(fc, &args);
1579 }
1580
1581 /*
1582 * Set attributes, and at the same time refresh them.
1583 *
1584 * Truncation is slightly complicated, because the 'truncate' request
1585 * may fail, in which case we don't want to touch the mapping.
1586 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1587 * and the actual truncation by hand.
1588 */
1589 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
1590 struct file *file)
1591 {
1592 struct fuse_conn *fc = get_fuse_conn(inode);
1593 struct fuse_inode *fi = get_fuse_inode(inode);
1594 FUSE_ARGS(args);
1595 struct fuse_setattr_in inarg;
1596 struct fuse_attr_out outarg;
1597 bool is_truncate = false;
1598 bool is_wb = fc->writeback_cache;
1599 loff_t oldsize;
1600 int err;
1601 bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1602
1603 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1604 attr->ia_valid |= ATTR_FORCE;
1605
1606 err = inode_change_ok(inode, attr);
1607 if (err)
1608 return err;
1609
1610 if (attr->ia_valid & ATTR_OPEN) {
1611 if (fc->atomic_o_trunc)
1612 return 0;
1613 file = NULL;
1614 }
1615
1616 if (attr->ia_valid & ATTR_SIZE)
1617 is_truncate = true;
1618
1619 if (is_truncate) {
1620 fuse_set_nowrite(inode);
1621 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1622 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1623 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1624 }
1625
1626 memset(&inarg, 0, sizeof(inarg));
1627 memset(&outarg, 0, sizeof(outarg));
1628 iattr_to_fattr(attr, &inarg, trust_local_cmtime);
1629 if (file) {
1630 struct fuse_file *ff = file->private_data;
1631 inarg.valid |= FATTR_FH;
1632 inarg.fh = ff->fh;
1633 }
1634 if (attr->ia_valid & ATTR_SIZE) {
1635 /* For mandatory locking in truncate */
1636 inarg.valid |= FATTR_LOCKOWNER;
1637 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1638 }
1639 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1640 err = fuse_simple_request(fc, &args);
1641 if (err) {
1642 if (err == -EINTR)
1643 fuse_invalidate_attr(inode);
1644 goto error;
1645 }
1646
1647 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1648 make_bad_inode(inode);
1649 err = -EIO;
1650 goto error;
1651 }
1652
1653 spin_lock(&fc->lock);
1654 /* the kernel maintains i_mtime locally */
1655 if (trust_local_cmtime) {
1656 if (attr->ia_valid & ATTR_MTIME)
1657 inode->i_mtime = attr->ia_mtime;
1658 if (attr->ia_valid & ATTR_CTIME)
1659 inode->i_ctime = attr->ia_ctime;
1660 /* FIXME: clear I_DIRTY_SYNC? */
1661 }
1662
1663 fuse_change_attributes_common(inode, &outarg.attr,
1664 attr_timeout(&outarg));
1665 oldsize = inode->i_size;
1666 /* see the comment in fuse_change_attributes() */
1667 if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1668 i_size_write(inode, outarg.attr.size);
1669
1670 if (is_truncate) {
1671 /* NOTE: this may release/reacquire fc->lock */
1672 __fuse_release_nowrite(inode);
1673 }
1674 spin_unlock(&fc->lock);
1675
1676 /*
1677 * Only call invalidate_inode_pages2() after removing
1678 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1679 */
1680 if ((is_truncate || !is_wb) &&
1681 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1682 truncate_pagecache(inode, outarg.attr.size);
1683 invalidate_inode_pages2(inode->i_mapping);
1684 }
1685
1686 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1687 return 0;
1688
1689 error:
1690 if (is_truncate)
1691 fuse_release_nowrite(inode);
1692
1693 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1694 return err;
1695 }
1696
1697 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1698 {
1699 struct inode *inode = d_inode(entry);
1700
1701 if (!fuse_allow_current_process(get_fuse_conn(inode)))
1702 return -EACCES;
1703
1704 if (attr->ia_valid & ATTR_FILE)
1705 return fuse_do_setattr(inode, attr, attr->ia_file);
1706 else
1707 return fuse_do_setattr(inode, attr, NULL);
1708 }
1709
1710 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1711 struct kstat *stat)
1712 {
1713 struct inode *inode = d_inode(entry);
1714 struct fuse_conn *fc = get_fuse_conn(inode);
1715
1716 if (!fuse_allow_current_process(fc))
1717 return -EACCES;
1718
1719 return fuse_update_attributes(inode, stat, NULL, NULL);
1720 }
1721
1722 static int fuse_setxattr(struct dentry *entry, const char *name,
1723 const void *value, size_t size, int flags)
1724 {
1725 struct inode *inode = d_inode(entry);
1726 struct fuse_conn *fc = get_fuse_conn(inode);
1727 FUSE_ARGS(args);
1728 struct fuse_setxattr_in inarg;
1729 int err;
1730
1731 if (fc->no_setxattr)
1732 return -EOPNOTSUPP;
1733
1734 memset(&inarg, 0, sizeof(inarg));
1735 inarg.size = size;
1736 inarg.flags = flags;
1737 args.in.h.opcode = FUSE_SETXATTR;
1738 args.in.h.nodeid = get_node_id(inode);
1739 args.in.numargs = 3;
1740 args.in.args[0].size = sizeof(inarg);
1741 args.in.args[0].value = &inarg;
1742 args.in.args[1].size = strlen(name) + 1;
1743 args.in.args[1].value = name;
1744 args.in.args[2].size = size;
1745 args.in.args[2].value = value;
1746 err = fuse_simple_request(fc, &args);
1747 if (err == -ENOSYS) {
1748 fc->no_setxattr = 1;
1749 err = -EOPNOTSUPP;
1750 }
1751 if (!err) {
1752 fuse_invalidate_attr(inode);
1753 fuse_update_ctime(inode);
1754 }
1755 return err;
1756 }
1757
1758 static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
1759 void *value, size_t size)
1760 {
1761 struct inode *inode = d_inode(entry);
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 = 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 .follow_link = fuse_follow_link,
1913 .put_link = free_page_put_link,
1914 .readlink = generic_readlink,
1915 .getattr = fuse_getattr,
1916 .setxattr = fuse_setxattr,
1917 .getxattr = fuse_getxattr,
1918 .listxattr = fuse_listxattr,
1919 .removexattr = fuse_removexattr,
1920 };
1921
1922 void fuse_init_common(struct inode *inode)
1923 {
1924 inode->i_op = &fuse_common_inode_operations;
1925 }
1926
1927 void fuse_init_dir(struct inode *inode)
1928 {
1929 inode->i_op = &fuse_dir_inode_operations;
1930 inode->i_fop = &fuse_dir_operations;
1931 }
1932
1933 void fuse_init_symlink(struct inode *inode)
1934 {
1935 inode->i_op = &fuse_symlink_inode_operations;
1936 }
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