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Linux 3.11-rc3
[linux-2.6.git] / fs / fuse / dir.c
blob72a5d5b04494ded2468bc4a2f5f30e30c9ca12f7
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 * Just mark the entry as stale, so that a next attempt to look it up
117 * will result in a new lookup call to userspace
118 *
119 * This is called when a dentry is about to become negative and the
120 * timeout is unknown (unlink, rmdir, rename and in some cases
121 * lookup)
122 */
123 void fuse_invalidate_entry_cache(struct dentry *entry)
124 {
125 fuse_dentry_settime(entry, 0);
126 }
127
128 /*
129 * Same as fuse_invalidate_entry_cache(), but also try to remove the
130 * dentry from the hash
131 */
132 static void fuse_invalidate_entry(struct dentry *entry)
133 {
134 d_invalidate(entry);
135 fuse_invalidate_entry_cache(entry);
136 }
137
138 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
139 u64 nodeid, struct qstr *name,
140 struct fuse_entry_out *outarg)
141 {
142 memset(outarg, 0, sizeof(struct fuse_entry_out));
143 req->in.h.opcode = FUSE_LOOKUP;
144 req->in.h.nodeid = nodeid;
145 req->in.numargs = 1;
146 req->in.args[0].size = name->len + 1;
147 req->in.args[0].value = name->name;
148 req->out.numargs = 1;
149 if (fc->minor < 9)
150 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
151 else
152 req->out.args[0].size = sizeof(struct fuse_entry_out);
153 req->out.args[0].value = outarg;
154 }
155
156 u64 fuse_get_attr_version(struct fuse_conn *fc)
157 {
158 u64 curr_version;
159
160 /*
161 * The spin lock isn't actually needed on 64bit archs, but we
162 * don't yet care too much about such optimizations.
163 */
164 spin_lock(&fc->lock);
165 curr_version = fc->attr_version;
166 spin_unlock(&fc->lock);
167
168 return curr_version;
169 }
170
171 /*
172 * Check whether the dentry is still valid
173 *
174 * If the entry validity timeout has expired and the dentry is
175 * positive, try to redo the lookup. If the lookup results in a
176 * different inode, then let the VFS invalidate the dentry and redo
177 * the lookup once more. If the lookup results in the same inode,
178 * then refresh the attributes, timeouts and mark the dentry valid.
179 */
180 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
181 {
182 struct inode *inode;
183 struct dentry *parent;
184 struct fuse_conn *fc;
185
186 inode = ACCESS_ONCE(entry->d_inode);
187 if (inode && is_bad_inode(inode))
188 return 0;
189 else if (fuse_dentry_time(entry) < get_jiffies_64()) {
190 int err;
191 struct fuse_entry_out outarg;
192 struct fuse_req *req;
193 struct fuse_forget_link *forget;
194 u64 attr_version;
195
196 /* For negative dentries, always do a fresh lookup */
197 if (!inode)
198 return 0;
199
200 if (flags & LOOKUP_RCU)
201 return -ECHILD;
202
203 fc = get_fuse_conn(inode);
204 req = fuse_get_req_nopages(fc);
205 if (IS_ERR(req))
206 return 0;
207
208 forget = fuse_alloc_forget();
209 if (!forget) {
210 fuse_put_request(fc, req);
211 return 0;
212 }
213
214 attr_version = fuse_get_attr_version(fc);
215
216 parent = dget_parent(entry);
217 fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
218 &entry->d_name, &outarg);
219 fuse_request_send(fc, req);
220 dput(parent);
221 err = req->out.h.error;
222 fuse_put_request(fc, req);
223 /* Zero nodeid is same as -ENOENT */
224 if (!err && !outarg.nodeid)
225 err = -ENOENT;
226 if (!err) {
227 struct fuse_inode *fi = get_fuse_inode(inode);
228 if (outarg.nodeid != get_node_id(inode)) {
229 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
230 return 0;
231 }
232 spin_lock(&fc->lock);
233 fi->nlookup++;
234 spin_unlock(&fc->lock);
235 }
236 kfree(forget);
237 if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
238 return 0;
239
240 fuse_change_attributes(inode, &outarg.attr,
241 entry_attr_timeout(&outarg),
242 attr_version);
243 fuse_change_entry_timeout(entry, &outarg);
244 } else if (inode) {
245 fc = get_fuse_conn(inode);
246 if (fc->readdirplus_auto) {
247 parent = dget_parent(entry);
248 fuse_advise_use_readdirplus(parent->d_inode);
249 dput(parent);
250 }
251 }
252 return 1;
253 }
254
255 static int invalid_nodeid(u64 nodeid)
256 {
257 return !nodeid || nodeid == FUSE_ROOT_ID;
258 }
259
260 const struct dentry_operations fuse_dentry_operations = {
261 .d_revalidate = fuse_dentry_revalidate,
262 };
263
264 int fuse_valid_type(int m)
265 {
266 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
267 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
268 }
269
270 /*
271 * Add a directory inode to a dentry, ensuring that no other dentry
272 * refers to this inode. Called with fc->inst_mutex.
273 */
274 static struct dentry *fuse_d_add_directory(struct dentry *entry,
275 struct inode *inode)
276 {
277 struct dentry *alias = d_find_alias(inode);
278 if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
279 /* This tries to shrink the subtree below alias */
280 fuse_invalidate_entry(alias);
281 dput(alias);
282 if (!hlist_empty(&inode->i_dentry))
283 return ERR_PTR(-EBUSY);
284 } else {
285 dput(alias);
286 }
287 return d_splice_alias(inode, entry);
288 }
289
290 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
291 struct fuse_entry_out *outarg, struct inode **inode)
292 {
293 struct fuse_conn *fc = get_fuse_conn_super(sb);
294 struct fuse_req *req;
295 struct fuse_forget_link *forget;
296 u64 attr_version;
297 int err;
298
299 *inode = NULL;
300 err = -ENAMETOOLONG;
301 if (name->len > FUSE_NAME_MAX)
302 goto out;
303
304 req = fuse_get_req_nopages(fc);
305 err = PTR_ERR(req);
306 if (IS_ERR(req))
307 goto out;
308
309 forget = fuse_alloc_forget();
310 err = -ENOMEM;
311 if (!forget) {
312 fuse_put_request(fc, req);
313 goto out;
314 }
315
316 attr_version = fuse_get_attr_version(fc);
317
318 fuse_lookup_init(fc, req, nodeid, name, outarg);
319 fuse_request_send(fc, req);
320 err = req->out.h.error;
321 fuse_put_request(fc, req);
322 /* Zero nodeid is same as -ENOENT, but with valid timeout */
323 if (err || !outarg->nodeid)
324 goto out_put_forget;
325
326 err = -EIO;
327 if (!outarg->nodeid)
328 goto out_put_forget;
329 if (!fuse_valid_type(outarg->attr.mode))
330 goto out_put_forget;
331
332 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
333 &outarg->attr, entry_attr_timeout(outarg),
334 attr_version);
335 err = -ENOMEM;
336 if (!*inode) {
337 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
338 goto out;
339 }
340 err = 0;
341
342 out_put_forget:
343 kfree(forget);
344 out:
345 return err;
346 }
347
348 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
349 unsigned int flags)
350 {
351 int err;
352 struct fuse_entry_out outarg;
353 struct inode *inode;
354 struct dentry *newent;
355 struct fuse_conn *fc = get_fuse_conn(dir);
356 bool outarg_valid = true;
357
358 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
359 &outarg, &inode);
360 if (err == -ENOENT) {
361 outarg_valid = false;
362 err = 0;
363 }
364 if (err)
365 goto out_err;
366
367 err = -EIO;
368 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
369 goto out_iput;
370
371 if (inode && S_ISDIR(inode->i_mode)) {
372 mutex_lock(&fc->inst_mutex);
373 newent = fuse_d_add_directory(entry, inode);
374 mutex_unlock(&fc->inst_mutex);
375 err = PTR_ERR(newent);
376 if (IS_ERR(newent))
377 goto out_iput;
378 } else {
379 newent = d_splice_alias(inode, entry);
380 }
381
382 entry = newent ? newent : entry;
383 if (outarg_valid)
384 fuse_change_entry_timeout(entry, &outarg);
385 else
386 fuse_invalidate_entry_cache(entry);
387
388 fuse_advise_use_readdirplus(dir);
389 return newent;
390
391 out_iput:
392 iput(inode);
393 out_err:
394 return ERR_PTR(err);
395 }
396
397 /*
398 * Atomic create+open operation
399 *
400 * If the filesystem doesn't support this, then fall back to separate
401 * 'mknod' + 'open' requests.
402 */
403 static int fuse_create_open(struct inode *dir, struct dentry *entry,
404 struct file *file, unsigned flags,
405 umode_t mode, int *opened)
406 {
407 int err;
408 struct inode *inode;
409 struct fuse_conn *fc = get_fuse_conn(dir);
410 struct fuse_req *req;
411 struct fuse_forget_link *forget;
412 struct fuse_create_in inarg;
413 struct fuse_open_out outopen;
414 struct fuse_entry_out outentry;
415 struct fuse_file *ff;
416
417 /* Userspace expects S_IFREG in create mode */
418 BUG_ON((mode & S_IFMT) != S_IFREG);
419
420 forget = fuse_alloc_forget();
421 err = -ENOMEM;
422 if (!forget)
423 goto out_err;
424
425 req = fuse_get_req_nopages(fc);
426 err = PTR_ERR(req);
427 if (IS_ERR(req))
428 goto out_put_forget_req;
429
430 err = -ENOMEM;
431 ff = fuse_file_alloc(fc);
432 if (!ff)
433 goto out_put_request;
434
435 if (!fc->dont_mask)
436 mode &= ~current_umask();
437
438 flags &= ~O_NOCTTY;
439 memset(&inarg, 0, sizeof(inarg));
440 memset(&outentry, 0, sizeof(outentry));
441 inarg.flags = flags;
442 inarg.mode = mode;
443 inarg.umask = current_umask();
444 req->in.h.opcode = FUSE_CREATE;
445 req->in.h.nodeid = get_node_id(dir);
446 req->in.numargs = 2;
447 req->in.args[0].size = fc->minor < 12 ? sizeof(struct fuse_open_in) :
448 sizeof(inarg);
449 req->in.args[0].value = &inarg;
450 req->in.args[1].size = entry->d_name.len + 1;
451 req->in.args[1].value = entry->d_name.name;
452 req->out.numargs = 2;
453 if (fc->minor < 9)
454 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
455 else
456 req->out.args[0].size = sizeof(outentry);
457 req->out.args[0].value = &outentry;
458 req->out.args[1].size = sizeof(outopen);
459 req->out.args[1].value = &outopen;
460 fuse_request_send(fc, req);
461 err = req->out.h.error;
462 if (err)
463 goto out_free_ff;
464
465 err = -EIO;
466 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
467 goto out_free_ff;
468
469 fuse_put_request(fc, req);
470 ff->fh = outopen.fh;
471 ff->nodeid = outentry.nodeid;
472 ff->open_flags = outopen.open_flags;
473 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
474 &outentry.attr, entry_attr_timeout(&outentry), 0);
475 if (!inode) {
476 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
477 fuse_sync_release(ff, flags);
478 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
479 err = -ENOMEM;
480 goto out_err;
481 }
482 kfree(forget);
483 d_instantiate(entry, inode);
484 fuse_change_entry_timeout(entry, &outentry);
485 fuse_invalidate_attr(dir);
486 err = finish_open(file, entry, generic_file_open, opened);
487 if (err) {
488 fuse_sync_release(ff, flags);
489 } else {
490 file->private_data = fuse_file_get(ff);
491 fuse_finish_open(inode, file);
492 }
493 return err;
494
495 out_free_ff:
496 fuse_file_free(ff);
497 out_put_request:
498 fuse_put_request(fc, req);
499 out_put_forget_req:
500 kfree(forget);
501 out_err:
502 return err;
503 }
504
505 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);
506 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
507 struct file *file, unsigned flags,
508 umode_t mode, int *opened)
509 {
510 int err;
511 struct fuse_conn *fc = get_fuse_conn(dir);
512 struct dentry *res = NULL;
513
514 if (d_unhashed(entry)) {
515 res = fuse_lookup(dir, entry, 0);
516 if (IS_ERR(res))
517 return PTR_ERR(res);
518
519 if (res)
520 entry = res;
521 }
522
523 if (!(flags & O_CREAT) || entry->d_inode)
524 goto no_open;
525
526 /* Only creates */
527 *opened |= FILE_CREATED;
528
529 if (fc->no_create)
530 goto mknod;
531
532 err = fuse_create_open(dir, entry, file, flags, mode, opened);
533 if (err == -ENOSYS) {
534 fc->no_create = 1;
535 goto mknod;
536 }
537 out_dput:
538 dput(res);
539 return err;
540
541 mknod:
542 err = fuse_mknod(dir, entry, mode, 0);
543 if (err)
544 goto out_dput;
545 no_open:
546 return finish_no_open(file, res);
547 }
548
549 /*
550 * Code shared between mknod, mkdir, symlink and link
551 */
552 static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
553 struct inode *dir, struct dentry *entry,
554 umode_t mode)
555 {
556 struct fuse_entry_out outarg;
557 struct inode *inode;
558 int err;
559 struct fuse_forget_link *forget;
560
561 forget = fuse_alloc_forget();
562 if (!forget) {
563 fuse_put_request(fc, req);
564 return -ENOMEM;
565 }
566
567 memset(&outarg, 0, sizeof(outarg));
568 req->in.h.nodeid = get_node_id(dir);
569 req->out.numargs = 1;
570 if (fc->minor < 9)
571 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
572 else
573 req->out.args[0].size = sizeof(outarg);
574 req->out.args[0].value = &outarg;
575 fuse_request_send(fc, req);
576 err = req->out.h.error;
577 fuse_put_request(fc, req);
578 if (err)
579 goto out_put_forget_req;
580
581 err = -EIO;
582 if (invalid_nodeid(outarg.nodeid))
583 goto out_put_forget_req;
584
585 if ((outarg.attr.mode ^ mode) & S_IFMT)
586 goto out_put_forget_req;
587
588 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
589 &outarg.attr, entry_attr_timeout(&outarg), 0);
590 if (!inode) {
591 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
592 return -ENOMEM;
593 }
594 kfree(forget);
595
596 if (S_ISDIR(inode->i_mode)) {
597 struct dentry *alias;
598 mutex_lock(&fc->inst_mutex);
599 alias = d_find_alias(inode);
600 if (alias) {
601 /* New directory must have moved since mkdir */
602 mutex_unlock(&fc->inst_mutex);
603 dput(alias);
604 iput(inode);
605 return -EBUSY;
606 }
607 d_instantiate(entry, inode);
608 mutex_unlock(&fc->inst_mutex);
609 } else
610 d_instantiate(entry, inode);
611
612 fuse_change_entry_timeout(entry, &outarg);
613 fuse_invalidate_attr(dir);
614 return 0;
615
616 out_put_forget_req:
617 kfree(forget);
618 return err;
619 }
620
621 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
622 dev_t rdev)
623 {
624 struct fuse_mknod_in inarg;
625 struct fuse_conn *fc = get_fuse_conn(dir);
626 struct fuse_req *req = fuse_get_req_nopages(fc);
627 if (IS_ERR(req))
628 return PTR_ERR(req);
629
630 if (!fc->dont_mask)
631 mode &= ~current_umask();
632
633 memset(&inarg, 0, sizeof(inarg));
634 inarg.mode = mode;
635 inarg.rdev = new_encode_dev(rdev);
636 inarg.umask = current_umask();
637 req->in.h.opcode = FUSE_MKNOD;
638 req->in.numargs = 2;
639 req->in.args[0].size = fc->minor < 12 ? FUSE_COMPAT_MKNOD_IN_SIZE :
640 sizeof(inarg);
641 req->in.args[0].value = &inarg;
642 req->in.args[1].size = entry->d_name.len + 1;
643 req->in.args[1].value = entry->d_name.name;
644 return create_new_entry(fc, req, dir, entry, mode);
645 }
646
647 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
648 bool excl)
649 {
650 return fuse_mknod(dir, entry, mode, 0);
651 }
652
653 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
654 {
655 struct fuse_mkdir_in inarg;
656 struct fuse_conn *fc = get_fuse_conn(dir);
657 struct fuse_req *req = fuse_get_req_nopages(fc);
658 if (IS_ERR(req))
659 return PTR_ERR(req);
660
661 if (!fc->dont_mask)
662 mode &= ~current_umask();
663
664 memset(&inarg, 0, sizeof(inarg));
665 inarg.mode = mode;
666 inarg.umask = current_umask();
667 req->in.h.opcode = FUSE_MKDIR;
668 req->in.numargs = 2;
669 req->in.args[0].size = sizeof(inarg);
670 req->in.args[0].value = &inarg;
671 req->in.args[1].size = entry->d_name.len + 1;
672 req->in.args[1].value = entry->d_name.name;
673 return create_new_entry(fc, req, dir, entry, S_IFDIR);
674 }
675
676 static int fuse_symlink(struct inode *dir, struct dentry *entry,
677 const char *link)
678 {
679 struct fuse_conn *fc = get_fuse_conn(dir);
680 unsigned len = strlen(link) + 1;
681 struct fuse_req *req = fuse_get_req_nopages(fc);
682 if (IS_ERR(req))
683 return PTR_ERR(req);
684
685 req->in.h.opcode = FUSE_SYMLINK;
686 req->in.numargs = 2;
687 req->in.args[0].size = entry->d_name.len + 1;
688 req->in.args[0].value = entry->d_name.name;
689 req->in.args[1].size = len;
690 req->in.args[1].value = link;
691 return create_new_entry(fc, req, dir, entry, S_IFLNK);
692 }
693
694 static int fuse_unlink(struct inode *dir, struct dentry *entry)
695 {
696 int err;
697 struct fuse_conn *fc = get_fuse_conn(dir);
698 struct fuse_req *req = fuse_get_req_nopages(fc);
699 if (IS_ERR(req))
700 return PTR_ERR(req);
701
702 req->in.h.opcode = FUSE_UNLINK;
703 req->in.h.nodeid = get_node_id(dir);
704 req->in.numargs = 1;
705 req->in.args[0].size = entry->d_name.len + 1;
706 req->in.args[0].value = entry->d_name.name;
707 fuse_request_send(fc, req);
708 err = req->out.h.error;
709 fuse_put_request(fc, req);
710 if (!err) {
711 struct inode *inode = entry->d_inode;
712 struct fuse_inode *fi = get_fuse_inode(inode);
713
714 spin_lock(&fc->lock);
715 fi->attr_version = ++fc->attr_version;
716 /*
717 * If i_nlink == 0 then unlink doesn't make sense, yet this can
718 * happen if userspace filesystem is careless. It would be
719 * difficult to enforce correct nlink usage so just ignore this
720 * condition here
721 */
722 if (inode->i_nlink > 0)
723 drop_nlink(inode);
724 spin_unlock(&fc->lock);
725 fuse_invalidate_attr(inode);
726 fuse_invalidate_attr(dir);
727 fuse_invalidate_entry_cache(entry);
728 } else if (err == -EINTR)
729 fuse_invalidate_entry(entry);
730 return err;
731 }
732
733 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
734 {
735 int err;
736 struct fuse_conn *fc = get_fuse_conn(dir);
737 struct fuse_req *req = fuse_get_req_nopages(fc);
738 if (IS_ERR(req))
739 return PTR_ERR(req);
740
741 req->in.h.opcode = FUSE_RMDIR;
742 req->in.h.nodeid = get_node_id(dir);
743 req->in.numargs = 1;
744 req->in.args[0].size = entry->d_name.len + 1;
745 req->in.args[0].value = entry->d_name.name;
746 fuse_request_send(fc, req);
747 err = req->out.h.error;
748 fuse_put_request(fc, req);
749 if (!err) {
750 clear_nlink(entry->d_inode);
751 fuse_invalidate_attr(dir);
752 fuse_invalidate_entry_cache(entry);
753 } else if (err == -EINTR)
754 fuse_invalidate_entry(entry);
755 return err;
756 }
757
758 static int fuse_rename(struct inode *olddir, struct dentry *oldent,
759 struct inode *newdir, struct dentry *newent)
760 {
761 int err;
762 struct fuse_rename_in inarg;
763 struct fuse_conn *fc = get_fuse_conn(olddir);
764 struct fuse_req *req = fuse_get_req_nopages(fc);
765
766 if (IS_ERR(req))
767 return PTR_ERR(req);
768
769 memset(&inarg, 0, sizeof(inarg));
770 inarg.newdir = get_node_id(newdir);
771 req->in.h.opcode = FUSE_RENAME;
772 req->in.h.nodeid = get_node_id(olddir);
773 req->in.numargs = 3;
774 req->in.args[0].size = sizeof(inarg);
775 req->in.args[0].value = &inarg;
776 req->in.args[1].size = oldent->d_name.len + 1;
777 req->in.args[1].value = oldent->d_name.name;
778 req->in.args[2].size = newent->d_name.len + 1;
779 req->in.args[2].value = newent->d_name.name;
780 fuse_request_send(fc, req);
781 err = req->out.h.error;
782 fuse_put_request(fc, req);
783 if (!err) {
784 /* ctime changes */
785 fuse_invalidate_attr(oldent->d_inode);
786
787 fuse_invalidate_attr(olddir);
788 if (olddir != newdir)
789 fuse_invalidate_attr(newdir);
790
791 /* newent will end up negative */
792 if (newent->d_inode) {
793 fuse_invalidate_attr(newent->d_inode);
794 fuse_invalidate_entry_cache(newent);
795 }
796 } else if (err == -EINTR) {
797 /* If request was interrupted, DEITY only knows if the
798 rename actually took place. If the invalidation
799 fails (e.g. some process has CWD under the renamed
800 directory), then there can be inconsistency between
801 the dcache and the real filesystem. Tough luck. */
802 fuse_invalidate_entry(oldent);
803 if (newent->d_inode)
804 fuse_invalidate_entry(newent);
805 }
806
807 return err;
808 }
809
810 static int fuse_link(struct dentry *entry, struct inode *newdir,
811 struct dentry *newent)
812 {
813 int err;
814 struct fuse_link_in inarg;
815 struct inode *inode = entry->d_inode;
816 struct fuse_conn *fc = get_fuse_conn(inode);
817 struct fuse_req *req = fuse_get_req_nopages(fc);
818 if (IS_ERR(req))
819 return PTR_ERR(req);
820
821 memset(&inarg, 0, sizeof(inarg));
822 inarg.oldnodeid = get_node_id(inode);
823 req->in.h.opcode = FUSE_LINK;
824 req->in.numargs = 2;
825 req->in.args[0].size = sizeof(inarg);
826 req->in.args[0].value = &inarg;
827 req->in.args[1].size = newent->d_name.len + 1;
828 req->in.args[1].value = newent->d_name.name;
829 err = create_new_entry(fc, req, newdir, newent, inode->i_mode);
830 /* Contrary to "normal" filesystems it can happen that link
831 makes two "logical" inodes point to the same "physical"
832 inode. We invalidate the attributes of the old one, so it
833 will reflect changes in the backing inode (link count,
834 etc.)
835 */
836 if (!err) {
837 struct fuse_inode *fi = get_fuse_inode(inode);
838
839 spin_lock(&fc->lock);
840 fi->attr_version = ++fc->attr_version;
841 inc_nlink(inode);
842 spin_unlock(&fc->lock);
843 fuse_invalidate_attr(inode);
844 } else if (err == -EINTR) {
845 fuse_invalidate_attr(inode);
846 }
847 return err;
848 }
849
850 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
851 struct kstat *stat)
852 {
853 unsigned int blkbits;
854
855 stat->dev = inode->i_sb->s_dev;
856 stat->ino = attr->ino;
857 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
858 stat->nlink = attr->nlink;
859 stat->uid = make_kuid(&init_user_ns, attr->uid);
860 stat->gid = make_kgid(&init_user_ns, attr->gid);
861 stat->rdev = inode->i_rdev;
862 stat->atime.tv_sec = attr->atime;
863 stat->atime.tv_nsec = attr->atimensec;
864 stat->mtime.tv_sec = attr->mtime;
865 stat->mtime.tv_nsec = attr->mtimensec;
866 stat->ctime.tv_sec = attr->ctime;
867 stat->ctime.tv_nsec = attr->ctimensec;
868 stat->size = attr->size;
869 stat->blocks = attr->blocks;
870
871 if (attr->blksize != 0)
872 blkbits = ilog2(attr->blksize);
873 else
874 blkbits = inode->i_sb->s_blocksize_bits;
875
876 stat->blksize = 1 << blkbits;
877 }
878
879 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
880 struct file *file)
881 {
882 int err;
883 struct fuse_getattr_in inarg;
884 struct fuse_attr_out outarg;
885 struct fuse_conn *fc = get_fuse_conn(inode);
886 struct fuse_req *req;
887 u64 attr_version;
888
889 req = fuse_get_req_nopages(fc);
890 if (IS_ERR(req))
891 return PTR_ERR(req);
892
893 attr_version = fuse_get_attr_version(fc);
894
895 memset(&inarg, 0, sizeof(inarg));
896 memset(&outarg, 0, sizeof(outarg));
897 /* Directories have separate file-handle space */
898 if (file && S_ISREG(inode->i_mode)) {
899 struct fuse_file *ff = file->private_data;
900
901 inarg.getattr_flags |= FUSE_GETATTR_FH;
902 inarg.fh = ff->fh;
903 }
904 req->in.h.opcode = FUSE_GETATTR;
905 req->in.h.nodeid = get_node_id(inode);
906 req->in.numargs = 1;
907 req->in.args[0].size = sizeof(inarg);
908 req->in.args[0].value = &inarg;
909 req->out.numargs = 1;
910 if (fc->minor < 9)
911 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
912 else
913 req->out.args[0].size = sizeof(outarg);
914 req->out.args[0].value = &outarg;
915 fuse_request_send(fc, req);
916 err = req->out.h.error;
917 fuse_put_request(fc, req);
918 if (!err) {
919 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
920 make_bad_inode(inode);
921 err = -EIO;
922 } else {
923 fuse_change_attributes(inode, &outarg.attr,
924 attr_timeout(&outarg),
925 attr_version);
926 if (stat)
927 fuse_fillattr(inode, &outarg.attr, stat);
928 }
929 }
930 return err;
931 }
932
933 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
934 struct file *file, bool *refreshed)
935 {
936 struct fuse_inode *fi = get_fuse_inode(inode);
937 int err;
938 bool r;
939
940 if (fi->i_time < get_jiffies_64()) {
941 r = true;
942 err = fuse_do_getattr(inode, stat, file);
943 } else {
944 r = false;
945 err = 0;
946 if (stat) {
947 generic_fillattr(inode, stat);
948 stat->mode = fi->orig_i_mode;
949 stat->ino = fi->orig_ino;
950 }
951 }
952
953 if (refreshed != NULL)
954 *refreshed = r;
955
956 return err;
957 }
958
959 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
960 u64 child_nodeid, struct qstr *name)
961 {
962 int err = -ENOTDIR;
963 struct inode *parent;
964 struct dentry *dir;
965 struct dentry *entry;
966
967 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
968 if (!parent)
969 return -ENOENT;
970
971 mutex_lock(&parent->i_mutex);
972 if (!S_ISDIR(parent->i_mode))
973 goto unlock;
974
975 err = -ENOENT;
976 dir = d_find_alias(parent);
977 if (!dir)
978 goto unlock;
979
980 entry = d_lookup(dir, name);
981 dput(dir);
982 if (!entry)
983 goto unlock;
984
985 fuse_invalidate_attr(parent);
986 fuse_invalidate_entry(entry);
987
988 if (child_nodeid != 0 && entry->d_inode) {
989 mutex_lock(&entry->d_inode->i_mutex);
990 if (get_node_id(entry->d_inode) != child_nodeid) {
991 err = -ENOENT;
992 goto badentry;
993 }
994 if (d_mountpoint(entry)) {
995 err = -EBUSY;
996 goto badentry;
997 }
998 if (S_ISDIR(entry->d_inode->i_mode)) {
999 shrink_dcache_parent(entry);
1000 if (!simple_empty(entry)) {
1001 err = -ENOTEMPTY;
1002 goto badentry;
1003 }
1004 entry->d_inode->i_flags |= S_DEAD;
1005 }
1006 dont_mount(entry);
1007 clear_nlink(entry->d_inode);
1008 err = 0;
1009 badentry:
1010 mutex_unlock(&entry->d_inode->i_mutex);
1011 if (!err)
1012 d_delete(entry);
1013 } else {
1014 err = 0;
1015 }
1016 dput(entry);
1017
1018 unlock:
1019 mutex_unlock(&parent->i_mutex);
1020 iput(parent);
1021 return err;
1022 }
1023
1024 /*
1025 * Calling into a user-controlled filesystem gives the filesystem
1026 * daemon ptrace-like capabilities over the current process. This
1027 * means, that the filesystem daemon is able to record the exact
1028 * filesystem operations performed, and can also control the behavior
1029 * of the requester process in otherwise impossible ways. For example
1030 * it can delay the operation for arbitrary length of time allowing
1031 * DoS against the requester.
1032 *
1033 * For this reason only those processes can call into the filesystem,
1034 * for which the owner of the mount has ptrace privilege. This
1035 * excludes processes started by other users, suid or sgid processes.
1036 */
1037 int fuse_allow_current_process(struct fuse_conn *fc)
1038 {
1039 const struct cred *cred;
1040
1041 if (fc->flags & FUSE_ALLOW_OTHER)
1042 return 1;
1043
1044 cred = current_cred();
1045 if (uid_eq(cred->euid, fc->user_id) &&
1046 uid_eq(cred->suid, fc->user_id) &&
1047 uid_eq(cred->uid, fc->user_id) &&
1048 gid_eq(cred->egid, fc->group_id) &&
1049 gid_eq(cred->sgid, fc->group_id) &&
1050 gid_eq(cred->gid, fc->group_id))
1051 return 1;
1052
1053 return 0;
1054 }
1055
1056 static int fuse_access(struct inode *inode, int mask)
1057 {
1058 struct fuse_conn *fc = get_fuse_conn(inode);
1059 struct fuse_req *req;
1060 struct fuse_access_in inarg;
1061 int err;
1062
1063 if (fc->no_access)
1064 return 0;
1065
1066 req = fuse_get_req_nopages(fc);
1067 if (IS_ERR(req))
1068 return PTR_ERR(req);
1069
1070 memset(&inarg, 0, sizeof(inarg));
1071 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1072 req->in.h.opcode = FUSE_ACCESS;
1073 req->in.h.nodeid = get_node_id(inode);
1074 req->in.numargs = 1;
1075 req->in.args[0].size = sizeof(inarg);
1076 req->in.args[0].value = &inarg;
1077 fuse_request_send(fc, req);
1078 err = req->out.h.error;
1079 fuse_put_request(fc, req);
1080 if (err == -ENOSYS) {
1081 fc->no_access = 1;
1082 err = 0;
1083 }
1084 return err;
1085 }
1086
1087 static int fuse_perm_getattr(struct inode *inode, int mask)
1088 {
1089 if (mask & MAY_NOT_BLOCK)
1090 return -ECHILD;
1091
1092 return fuse_do_getattr(inode, NULL, NULL);
1093 }
1094
1095 /*
1096 * Check permission. The two basic access models of FUSE are:
1097 *
1098 * 1) Local access checking ('default_permissions' mount option) based
1099 * on file mode. This is the plain old disk filesystem permission
1100 * modell.
1101 *
1102 * 2) "Remote" access checking, where server is responsible for
1103 * checking permission in each inode operation. An exception to this
1104 * is if ->permission() was invoked from sys_access() in which case an
1105 * access request is sent. Execute permission is still checked
1106 * locally based on file mode.
1107 */
1108 static int fuse_permission(struct inode *inode, int mask)
1109 {
1110 struct fuse_conn *fc = get_fuse_conn(inode);
1111 bool refreshed = false;
1112 int err = 0;
1113
1114 if (!fuse_allow_current_process(fc))
1115 return -EACCES;
1116
1117 /*
1118 * If attributes are needed, refresh them before proceeding
1119 */
1120 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1121 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1122 struct fuse_inode *fi = get_fuse_inode(inode);
1123
1124 if (fi->i_time < get_jiffies_64()) {
1125 refreshed = true;
1126
1127 err = fuse_perm_getattr(inode, mask);
1128 if (err)
1129 return err;
1130 }
1131 }
1132
1133 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1134 err = generic_permission(inode, mask);
1135
1136 /* If permission is denied, try to refresh file
1137 attributes. This is also needed, because the root
1138 node will at first have no permissions */
1139 if (err == -EACCES && !refreshed) {
1140 err = fuse_perm_getattr(inode, mask);
1141 if (!err)
1142 err = generic_permission(inode, mask);
1143 }
1144
1145 /* Note: the opposite of the above test does not
1146 exist. So if permissions are revoked this won't be
1147 noticed immediately, only after the attribute
1148 timeout has expired */
1149 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1150 if (mask & MAY_NOT_BLOCK)
1151 return -ECHILD;
1152
1153 err = fuse_access(inode, mask);
1154 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1155 if (!(inode->i_mode & S_IXUGO)) {
1156 if (refreshed)
1157 return -EACCES;
1158
1159 err = fuse_perm_getattr(inode, mask);
1160 if (!err && !(inode->i_mode & S_IXUGO))
1161 return -EACCES;
1162 }
1163 }
1164 return err;
1165 }
1166
1167 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1168 struct dir_context *ctx)
1169 {
1170 while (nbytes >= FUSE_NAME_OFFSET) {
1171 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1172 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1173 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1174 return -EIO;
1175 if (reclen > nbytes)
1176 break;
1177
1178 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1179 dirent->ino, dirent->type))
1180 break;
1181
1182 buf += reclen;
1183 nbytes -= reclen;
1184 ctx->pos = dirent->off;
1185 }
1186
1187 return 0;
1188 }
1189
1190 static int fuse_direntplus_link(struct file *file,
1191 struct fuse_direntplus *direntplus,
1192 u64 attr_version)
1193 {
1194 int err;
1195 struct fuse_entry_out *o = &direntplus->entry_out;
1196 struct fuse_dirent *dirent = &direntplus->dirent;
1197 struct dentry *parent = file->f_path.dentry;
1198 struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1199 struct dentry *dentry;
1200 struct dentry *alias;
1201 struct inode *dir = parent->d_inode;
1202 struct fuse_conn *fc;
1203 struct inode *inode;
1204
1205 if (!o->nodeid) {
1206 /*
1207 * Unlike in the case of fuse_lookup, zero nodeid does not mean
1208 * ENOENT. Instead, it only means the userspace filesystem did
1209 * not want to return attributes/handle for this entry.
1210 *
1211 * So do nothing.
1212 */
1213 return 0;
1214 }
1215
1216 if (name.name[0] == '.') {
1217 /*
1218 * We could potentially refresh the attributes of the directory
1219 * and its parent?
1220 */
1221 if (name.len == 1)
1222 return 0;
1223 if (name.name[1] == '.' && name.len == 2)
1224 return 0;
1225 }
1226
1227 if (invalid_nodeid(o->nodeid))
1228 return -EIO;
1229 if (!fuse_valid_type(o->attr.mode))
1230 return -EIO;
1231
1232 fc = get_fuse_conn(dir);
1233
1234 name.hash = full_name_hash(name.name, name.len);
1235 dentry = d_lookup(parent, &name);
1236 if (dentry) {
1237 inode = dentry->d_inode;
1238 if (!inode) {
1239 d_drop(dentry);
1240 } else if (get_node_id(inode) != o->nodeid ||
1241 ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1242 err = d_invalidate(dentry);
1243 if (err)
1244 goto out;
1245 } else if (is_bad_inode(inode)) {
1246 err = -EIO;
1247 goto out;
1248 } else {
1249 struct fuse_inode *fi;
1250 fi = get_fuse_inode(inode);
1251 spin_lock(&fc->lock);
1252 fi->nlookup++;
1253 spin_unlock(&fc->lock);
1254
1255 fuse_change_attributes(inode, &o->attr,
1256 entry_attr_timeout(o),
1257 attr_version);
1258
1259 /*
1260 * The other branch to 'found' comes via fuse_iget()
1261 * which bumps nlookup inside
1262 */
1263 goto found;
1264 }
1265 dput(dentry);
1266 }
1267
1268 dentry = d_alloc(parent, &name);
1269 err = -ENOMEM;
1270 if (!dentry)
1271 goto out;
1272
1273 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1274 &o->attr, entry_attr_timeout(o), attr_version);
1275 if (!inode)
1276 goto out;
1277
1278 if (S_ISDIR(inode->i_mode)) {
1279 mutex_lock(&fc->inst_mutex);
1280 alias = fuse_d_add_directory(dentry, inode);
1281 mutex_unlock(&fc->inst_mutex);
1282 err = PTR_ERR(alias);
1283 if (IS_ERR(alias)) {
1284 iput(inode);
1285 goto out;
1286 }
1287 } else {
1288 alias = d_splice_alias(inode, dentry);
1289 }
1290
1291 if (alias) {
1292 dput(dentry);
1293 dentry = alias;
1294 }
1295
1296 found:
1297 fuse_change_entry_timeout(dentry, o);
1298
1299 err = 0;
1300 out:
1301 dput(dentry);
1302 return err;
1303 }
1304
1305 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1306 struct dir_context *ctx, u64 attr_version)
1307 {
1308 struct fuse_direntplus *direntplus;
1309 struct fuse_dirent *dirent;
1310 size_t reclen;
1311 int over = 0;
1312 int ret;
1313
1314 while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1315 direntplus = (struct fuse_direntplus *) buf;
1316 dirent = &direntplus->dirent;
1317 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1318
1319 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1320 return -EIO;
1321 if (reclen > nbytes)
1322 break;
1323
1324 if (!over) {
1325 /* We fill entries into dstbuf only as much as
1326 it can hold. But we still continue iterating
1327 over remaining entries to link them. If not,
1328 we need to send a FORGET for each of those
1329 which we did not link.
1330 */
1331 over = !dir_emit(ctx, dirent->name, dirent->namelen,
1332 dirent->ino, dirent->type);
1333 ctx->pos = dirent->off;
1334 }
1335
1336 buf += reclen;
1337 nbytes -= reclen;
1338
1339 ret = fuse_direntplus_link(file, direntplus, attr_version);
1340 if (ret)
1341 fuse_force_forget(file, direntplus->entry_out.nodeid);
1342 }
1343
1344 return 0;
1345 }
1346
1347 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1348 {
1349 int plus, err;
1350 size_t nbytes;
1351 struct page *page;
1352 struct inode *inode = file_inode(file);
1353 struct fuse_conn *fc = get_fuse_conn(inode);
1354 struct fuse_req *req;
1355 u64 attr_version = 0;
1356
1357 if (is_bad_inode(inode))
1358 return -EIO;
1359
1360 req = fuse_get_req(fc, 1);
1361 if (IS_ERR(req))
1362 return PTR_ERR(req);
1363
1364 page = alloc_page(GFP_KERNEL);
1365 if (!page) {
1366 fuse_put_request(fc, req);
1367 return -ENOMEM;
1368 }
1369
1370 plus = fuse_use_readdirplus(inode, ctx);
1371 req->out.argpages = 1;
1372 req->num_pages = 1;
1373 req->pages[0] = page;
1374 req->page_descs[0].length = PAGE_SIZE;
1375 if (plus) {
1376 attr_version = fuse_get_attr_version(fc);
1377 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1378 FUSE_READDIRPLUS);
1379 } else {
1380 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1381 FUSE_READDIR);
1382 }
1383 fuse_request_send(fc, req);
1384 nbytes = req->out.args[0].size;
1385 err = req->out.h.error;
1386 fuse_put_request(fc, req);
1387 if (!err) {
1388 if (plus) {
1389 err = parse_dirplusfile(page_address(page), nbytes,
1390 file, ctx,
1391 attr_version);
1392 } else {
1393 err = parse_dirfile(page_address(page), nbytes, file,
1394 ctx);
1395 }
1396 }
1397
1398 __free_page(page);
1399 fuse_invalidate_attr(inode); /* atime changed */
1400 return err;
1401 }
1402
1403 static char *read_link(struct dentry *dentry)
1404 {
1405 struct inode *inode = dentry->d_inode;
1406 struct fuse_conn *fc = get_fuse_conn(inode);
1407 struct fuse_req *req = fuse_get_req_nopages(fc);
1408 char *link;
1409
1410 if (IS_ERR(req))
1411 return ERR_CAST(req);
1412
1413 link = (char *) __get_free_page(GFP_KERNEL);
1414 if (!link) {
1415 link = ERR_PTR(-ENOMEM);
1416 goto out;
1417 }
1418 req->in.h.opcode = FUSE_READLINK;
1419 req->in.h.nodeid = get_node_id(inode);
1420 req->out.argvar = 1;
1421 req->out.numargs = 1;
1422 req->out.args[0].size = PAGE_SIZE - 1;
1423 req->out.args[0].value = link;
1424 fuse_request_send(fc, req);
1425 if (req->out.h.error) {
1426 free_page((unsigned long) link);
1427 link = ERR_PTR(req->out.h.error);
1428 } else
1429 link[req->out.args[0].size] = '\0';
1430 out:
1431 fuse_put_request(fc, req);
1432 fuse_invalidate_attr(inode); /* atime changed */
1433 return link;
1434 }
1435
1436 static void free_link(char *link)
1437 {
1438 if (!IS_ERR(link))
1439 free_page((unsigned long) link);
1440 }
1441
1442 static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
1443 {
1444 nd_set_link(nd, read_link(dentry));
1445 return NULL;
1446 }
1447
1448 static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
1449 {
1450 free_link(nd_get_link(nd));
1451 }
1452
1453 static int fuse_dir_open(struct inode *inode, struct file *file)
1454 {
1455 return fuse_open_common(inode, file, true);
1456 }
1457
1458 static int fuse_dir_release(struct inode *inode, struct file *file)
1459 {
1460 fuse_release_common(file, FUSE_RELEASEDIR);
1461
1462 return 0;
1463 }
1464
1465 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1466 int datasync)
1467 {
1468 return fuse_fsync_common(file, start, end, datasync, 1);
1469 }
1470
1471 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1472 unsigned long arg)
1473 {
1474 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1475
1476 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1477 if (fc->minor < 18)
1478 return -ENOTTY;
1479
1480 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1481 }
1482
1483 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1484 unsigned long arg)
1485 {
1486 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1487
1488 if (fc->minor < 18)
1489 return -ENOTTY;
1490
1491 return fuse_ioctl_common(file, cmd, arg,
1492 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1493 }
1494
1495 static bool update_mtime(unsigned ivalid)
1496 {
1497 /* Always update if mtime is explicitly set */
1498 if (ivalid & ATTR_MTIME_SET)
1499 return true;
1500
1501 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1502 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1503 return false;
1504
1505 /* In all other cases update */
1506 return true;
1507 }
1508
1509 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
1510 {
1511 unsigned ivalid = iattr->ia_valid;
1512
1513 if (ivalid & ATTR_MODE)
1514 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1515 if (ivalid & ATTR_UID)
1516 arg->valid |= FATTR_UID, arg->uid = from_kuid(&init_user_ns, iattr->ia_uid);
1517 if (ivalid & ATTR_GID)
1518 arg->valid |= FATTR_GID, arg->gid = from_kgid(&init_user_ns, iattr->ia_gid);
1519 if (ivalid & ATTR_SIZE)
1520 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1521 if (ivalid & ATTR_ATIME) {
1522 arg->valid |= FATTR_ATIME;
1523 arg->atime = iattr->ia_atime.tv_sec;
1524 arg->atimensec = iattr->ia_atime.tv_nsec;
1525 if (!(ivalid & ATTR_ATIME_SET))
1526 arg->valid |= FATTR_ATIME_NOW;
1527 }
1528 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid)) {
1529 arg->valid |= FATTR_MTIME;
1530 arg->mtime = iattr->ia_mtime.tv_sec;
1531 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1532 if (!(ivalid & ATTR_MTIME_SET))
1533 arg->valid |= FATTR_MTIME_NOW;
1534 }
1535 }
1536
1537 /*
1538 * Prevent concurrent writepages on inode
1539 *
1540 * This is done by adding a negative bias to the inode write counter
1541 * and waiting for all pending writes to finish.
1542 */
1543 void fuse_set_nowrite(struct inode *inode)
1544 {
1545 struct fuse_conn *fc = get_fuse_conn(inode);
1546 struct fuse_inode *fi = get_fuse_inode(inode);
1547
1548 BUG_ON(!mutex_is_locked(&inode->i_mutex));
1549
1550 spin_lock(&fc->lock);
1551 BUG_ON(fi->writectr < 0);
1552 fi->writectr += FUSE_NOWRITE;
1553 spin_unlock(&fc->lock);
1554 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1555 }
1556
1557 /*
1558 * Allow writepages on inode
1559 *
1560 * Remove the bias from the writecounter and send any queued
1561 * writepages.
1562 */
1563 static void __fuse_release_nowrite(struct inode *inode)
1564 {
1565 struct fuse_inode *fi = get_fuse_inode(inode);
1566
1567 BUG_ON(fi->writectr != FUSE_NOWRITE);
1568 fi->writectr = 0;
1569 fuse_flush_writepages(inode);
1570 }
1571
1572 void fuse_release_nowrite(struct inode *inode)
1573 {
1574 struct fuse_conn *fc = get_fuse_conn(inode);
1575
1576 spin_lock(&fc->lock);
1577 __fuse_release_nowrite(inode);
1578 spin_unlock(&fc->lock);
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_req *req;
1594 struct fuse_setattr_in inarg;
1595 struct fuse_attr_out outarg;
1596 bool is_truncate = false;
1597 loff_t oldsize;
1598 int err;
1599
1600 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1601 attr->ia_valid |= ATTR_FORCE;
1602
1603 err = inode_change_ok(inode, attr);
1604 if (err)
1605 return err;
1606
1607 if (attr->ia_valid & ATTR_OPEN) {
1608 if (fc->atomic_o_trunc)
1609 return 0;
1610 file = NULL;
1611 }
1612
1613 if (attr->ia_valid & ATTR_SIZE)
1614 is_truncate = true;
1615
1616 req = fuse_get_req_nopages(fc);
1617 if (IS_ERR(req))
1618 return PTR_ERR(req);
1619
1620 if (is_truncate)
1621 fuse_set_nowrite(inode);
1622
1623 memset(&inarg, 0, sizeof(inarg));
1624 memset(&outarg, 0, sizeof(outarg));
1625 iattr_to_fattr(attr, &inarg);
1626 if (file) {
1627 struct fuse_file *ff = file->private_data;
1628 inarg.valid |= FATTR_FH;
1629 inarg.fh = ff->fh;
1630 }
1631 if (attr->ia_valid & ATTR_SIZE) {
1632 /* For mandatory locking in truncate */
1633 inarg.valid |= FATTR_LOCKOWNER;
1634 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1635 }
1636 req->in.h.opcode = FUSE_SETATTR;
1637 req->in.h.nodeid = get_node_id(inode);
1638 req->in.numargs = 1;
1639 req->in.args[0].size = sizeof(inarg);
1640 req->in.args[0].value = &inarg;
1641 req->out.numargs = 1;
1642 if (fc->minor < 9)
1643 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
1644 else
1645 req->out.args[0].size = sizeof(outarg);
1646 req->out.args[0].value = &outarg;
1647 fuse_request_send(fc, req);
1648 err = req->out.h.error;
1649 fuse_put_request(fc, req);
1650 if (err) {
1651 if (err == -EINTR)
1652 fuse_invalidate_attr(inode);
1653 goto error;
1654 }
1655
1656 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1657 make_bad_inode(inode);
1658 err = -EIO;
1659 goto error;
1660 }
1661
1662 spin_lock(&fc->lock);
1663 fuse_change_attributes_common(inode, &outarg.attr,
1664 attr_timeout(&outarg));
1665 oldsize = inode->i_size;
1666 i_size_write(inode, outarg.attr.size);
1667
1668 if (is_truncate) {
1669 /* NOTE: this may release/reacquire fc->lock */
1670 __fuse_release_nowrite(inode);
1671 }
1672 spin_unlock(&fc->lock);
1673
1674 /*
1675 * Only call invalidate_inode_pages2() after removing
1676 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1677 */
1678 if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1679 truncate_pagecache(inode, oldsize, outarg.attr.size);
1680 invalidate_inode_pages2(inode->i_mapping);
1681 }
1682
1683 return 0;
1684
1685 error:
1686 if (is_truncate)
1687 fuse_release_nowrite(inode);
1688
1689 return err;
1690 }
1691
1692 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1693 {
1694 struct inode *inode = entry->d_inode;
1695
1696 if (!fuse_allow_current_process(get_fuse_conn(inode)))
1697 return -EACCES;
1698
1699 if (attr->ia_valid & ATTR_FILE)
1700 return fuse_do_setattr(inode, attr, attr->ia_file);
1701 else
1702 return fuse_do_setattr(inode, attr, NULL);
1703 }
1704
1705 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1706 struct kstat *stat)
1707 {
1708 struct inode *inode = entry->d_inode;
1709 struct fuse_conn *fc = get_fuse_conn(inode);
1710
1711 if (!fuse_allow_current_process(fc))
1712 return -EACCES;
1713
1714 return fuse_update_attributes(inode, stat, NULL, NULL);
1715 }
1716
1717 static int fuse_setxattr(struct dentry *entry, const char *name,
1718 const void *value, size_t size, int flags)
1719 {
1720 struct inode *inode = entry->d_inode;
1721 struct fuse_conn *fc = get_fuse_conn(inode);
1722 struct fuse_req *req;
1723 struct fuse_setxattr_in inarg;
1724 int err;
1725
1726 if (fc->no_setxattr)
1727 return -EOPNOTSUPP;
1728
1729 req = fuse_get_req_nopages(fc);
1730 if (IS_ERR(req))
1731 return PTR_ERR(req);
1732
1733 memset(&inarg, 0, sizeof(inarg));
1734 inarg.size = size;
1735 inarg.flags = flags;
1736 req->in.h.opcode = FUSE_SETXATTR;
1737 req->in.h.nodeid = get_node_id(inode);
1738 req->in.numargs = 3;
1739 req->in.args[0].size = sizeof(inarg);
1740 req->in.args[0].value = &inarg;
1741 req->in.args[1].size = strlen(name) + 1;
1742 req->in.args[1].value = name;
1743 req->in.args[2].size = size;
1744 req->in.args[2].value = value;
1745 fuse_request_send(fc, req);
1746 err = req->out.h.error;
1747 fuse_put_request(fc, req);
1748 if (err == -ENOSYS) {
1749 fc->no_setxattr = 1;
1750 err = -EOPNOTSUPP;
1751 }
1752 return err;
1753 }
1754
1755 static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
1756 void *value, size_t size)
1757 {
1758 struct inode *inode = entry->d_inode;
1759 struct fuse_conn *fc = get_fuse_conn(inode);
1760 struct fuse_req *req;
1761 struct fuse_getxattr_in inarg;
1762 struct fuse_getxattr_out outarg;
1763 ssize_t ret;
1764
1765 if (fc->no_getxattr)
1766 return -EOPNOTSUPP;
1767
1768 req = fuse_get_req_nopages(fc);
1769 if (IS_ERR(req))
1770 return PTR_ERR(req);
1771
1772 memset(&inarg, 0, sizeof(inarg));
1773 inarg.size = size;
1774 req->in.h.opcode = FUSE_GETXATTR;
1775 req->in.h.nodeid = get_node_id(inode);
1776 req->in.numargs = 2;
1777 req->in.args[0].size = sizeof(inarg);
1778 req->in.args[0].value = &inarg;
1779 req->in.args[1].size = strlen(name) + 1;
1780 req->in.args[1].value = name;
1781 /* This is really two different operations rolled into one */
1782 req->out.numargs = 1;
1783 if (size) {
1784 req->out.argvar = 1;
1785 req->out.args[0].size = size;
1786 req->out.args[0].value = value;
1787 } else {
1788 req->out.args[0].size = sizeof(outarg);
1789 req->out.args[0].value = &outarg;
1790 }
1791 fuse_request_send(fc, req);
1792 ret = req->out.h.error;
1793 if (!ret)
1794 ret = size ? req->out.args[0].size : outarg.size;
1795 else {
1796 if (ret == -ENOSYS) {
1797 fc->no_getxattr = 1;
1798 ret = -EOPNOTSUPP;
1799 }
1800 }
1801 fuse_put_request(fc, req);
1802 return ret;
1803 }
1804
1805 static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
1806 {
1807 struct inode *inode = entry->d_inode;
1808 struct fuse_conn *fc = get_fuse_conn(inode);
1809 struct fuse_req *req;
1810 struct fuse_getxattr_in inarg;
1811 struct fuse_getxattr_out outarg;
1812 ssize_t ret;
1813
1814 if (!fuse_allow_current_process(fc))
1815 return -EACCES;
1816
1817 if (fc->no_listxattr)
1818 return -EOPNOTSUPP;
1819
1820 req = fuse_get_req_nopages(fc);
1821 if (IS_ERR(req))
1822 return PTR_ERR(req);
1823
1824 memset(&inarg, 0, sizeof(inarg));
1825 inarg.size = size;
1826 req->in.h.opcode = FUSE_LISTXATTR;
1827 req->in.h.nodeid = get_node_id(inode);
1828 req->in.numargs = 1;
1829 req->in.args[0].size = sizeof(inarg);
1830 req->in.args[0].value = &inarg;
1831 /* This is really two different operations rolled into one */
1832 req->out.numargs = 1;
1833 if (size) {
1834 req->out.argvar = 1;
1835 req->out.args[0].size = size;
1836 req->out.args[0].value = list;
1837 } else {
1838 req->out.args[0].size = sizeof(outarg);
1839 req->out.args[0].value = &outarg;
1840 }
1841 fuse_request_send(fc, req);
1842 ret = req->out.h.error;
1843 if (!ret)
1844 ret = size ? req->out.args[0].size : outarg.size;
1845 else {
1846 if (ret == -ENOSYS) {
1847 fc->no_listxattr = 1;
1848 ret = -EOPNOTSUPP;
1849 }
1850 }
1851 fuse_put_request(fc, req);
1852 return ret;
1853 }
1854
1855 static int fuse_removexattr(struct dentry *entry, const char *name)
1856 {
1857 struct inode *inode = entry->d_inode;
1858 struct fuse_conn *fc = get_fuse_conn(inode);
1859 struct fuse_req *req;
1860 int err;
1861
1862 if (fc->no_removexattr)
1863 return -EOPNOTSUPP;
1864
1865 req = fuse_get_req_nopages(fc);
1866 if (IS_ERR(req))
1867 return PTR_ERR(req);
1868
1869 req->in.h.opcode = FUSE_REMOVEXATTR;
1870 req->in.h.nodeid = get_node_id(inode);
1871 req->in.numargs = 1;
1872 req->in.args[0].size = strlen(name) + 1;
1873 req->in.args[0].value = name;
1874 fuse_request_send(fc, req);
1875 err = req->out.h.error;
1876 fuse_put_request(fc, req);
1877 if (err == -ENOSYS) {
1878 fc->no_removexattr = 1;
1879 err = -EOPNOTSUPP;
1880 }
1881 return err;
1882 }
1883
1884 static const struct inode_operations fuse_dir_inode_operations = {
1885 .lookup = fuse_lookup,
1886 .mkdir = fuse_mkdir,
1887 .symlink = fuse_symlink,
1888 .unlink = fuse_unlink,
1889 .rmdir = fuse_rmdir,
1890 .rename = fuse_rename,
1891 .link = fuse_link,
1892 .setattr = fuse_setattr,
1893 .create = fuse_create,
1894 .atomic_open = fuse_atomic_open,
1895 .mknod = fuse_mknod,
1896 .permission = fuse_permission,
1897 .getattr = fuse_getattr,
1898 .setxattr = fuse_setxattr,
1899 .getxattr = fuse_getxattr,
1900 .listxattr = fuse_listxattr,
1901 .removexattr = fuse_removexattr,
1902 };
1903
1904 static const struct file_operations fuse_dir_operations = {
1905 .llseek = generic_file_llseek,
1906 .read = generic_read_dir,
1907 .iterate = fuse_readdir,
1908 .open = fuse_dir_open,
1909 .release = fuse_dir_release,
1910 .fsync = fuse_dir_fsync,
1911 .unlocked_ioctl = fuse_dir_ioctl,
1912 .compat_ioctl = fuse_dir_compat_ioctl,
1913 };
1914
1915 static const struct inode_operations fuse_common_inode_operations = {
1916 .setattr = fuse_setattr,
1917 .permission = fuse_permission,
1918 .getattr = fuse_getattr,
1919 .setxattr = fuse_setxattr,
1920 .getxattr = fuse_getxattr,
1921 .listxattr = fuse_listxattr,
1922 .removexattr = fuse_removexattr,
1923 };
1924
1925 static const struct inode_operations fuse_symlink_inode_operations = {
1926 .setattr = fuse_setattr,
1927 .follow_link = fuse_follow_link,
1928 .put_link = fuse_put_link,
1929 .readlink = generic_readlink,
1930 .getattr = fuse_getattr,
1931 .setxattr = fuse_setxattr,
1932 .getxattr = fuse_getxattr,
1933 .listxattr = fuse_listxattr,
1934 .removexattr = fuse_removexattr,
1935 };
1936
1937 void fuse_init_common(struct inode *inode)
1938 {
1939 inode->i_op = &fuse_common_inode_operations;
1940 }
1941
1942 void fuse_init_dir(struct inode *inode)
1943 {
1944 inode->i_op = &fuse_dir_inode_operations;
1945 inode->i_fop = &fuse_dir_operations;
1946 }
1947
1948 void fuse_init_symlink(struct inode *inode)
1949 {
1950 inode->i_op = &fuse_symlink_inode_operations;
1951 }
Linus' kernel tree