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Merge 4.14.42 into android-4.14
[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / fs / fuse / dev.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/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/sched/signal.h>
15 #include <linux/uio.h>
16 #include <linux/miscdevice.h>
17 #include <linux/namei.h>
18 #include <linux/pagemap.h>
19 #include <linux/file.h>
20 #include <linux/slab.h>
21 #include <linux/pipe_fs_i.h>
22 #include <linux/swap.h>
23 #include <linux/splice.h>
24 #include <linux/sched.h>
25 #include <linux/freezer.h>
26
27 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
28 MODULE_ALIAS("devname:fuse");
29
30 static struct kmem_cache *fuse_req_cachep;
31
32 static struct fuse_dev *fuse_get_dev(struct file *file)
33 {
34 /*
35 * Lockless access is OK, because file->private data is set
36 * once during mount and is valid until the file is released.
37 */
38 return ACCESS_ONCE(file->private_data);
39 }
40
41 static void fuse_request_init(struct fuse_req *req, struct page **pages,
42 struct fuse_page_desc *page_descs,
43 unsigned npages)
44 {
45 memset(req, 0, sizeof(*req));
46 memset(pages, 0, sizeof(*pages) * npages);
47 memset(page_descs, 0, sizeof(*page_descs) * npages);
48 INIT_LIST_HEAD(&req->list);
49 INIT_LIST_HEAD(&req->intr_entry);
50 init_waitqueue_head(&req->waitq);
51 refcount_set(&req->count, 1);
52 req->pages = pages;
53 req->page_descs = page_descs;
54 req->max_pages = npages;
55 __set_bit(FR_PENDING, &req->flags);
56 }
57
58 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
59 {
60 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
61 if (req) {
62 struct page **pages;
63 struct fuse_page_desc *page_descs;
64
65 if (npages <= FUSE_REQ_INLINE_PAGES) {
66 pages = req->inline_pages;
67 page_descs = req->inline_page_descs;
68 } else {
69 pages = kmalloc(sizeof(struct page *) * npages, flags);
70 page_descs = kmalloc(sizeof(struct fuse_page_desc) *
71 npages, flags);
72 }
73
74 if (!pages || !page_descs) {
75 kfree(pages);
76 kfree(page_descs);
77 kmem_cache_free(fuse_req_cachep, req);
78 return NULL;
79 }
80
81 fuse_request_init(req, pages, page_descs, npages);
82 }
83 return req;
84 }
85
86 struct fuse_req *fuse_request_alloc(unsigned npages)
87 {
88 return __fuse_request_alloc(npages, GFP_KERNEL);
89 }
90 EXPORT_SYMBOL_GPL(fuse_request_alloc);
91
92 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
93 {
94 return __fuse_request_alloc(npages, GFP_NOFS);
95 }
96
97 void fuse_request_free(struct fuse_req *req)
98 {
99 if (req->pages != req->inline_pages) {
100 kfree(req->pages);
101 kfree(req->page_descs);
102 }
103 kmem_cache_free(fuse_req_cachep, req);
104 }
105
106 void __fuse_get_request(struct fuse_req *req)
107 {
108 refcount_inc(&req->count);
109 }
110
111 /* Must be called with > 1 refcount */
112 static void __fuse_put_request(struct fuse_req *req)
113 {
114 refcount_dec(&req->count);
115 }
116
117 static void fuse_req_init_context(struct fuse_conn *fc, struct fuse_req *req)
118 {
119 req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
120 req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
121 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
122 }
123
124 void fuse_set_initialized(struct fuse_conn *fc)
125 {
126 /* Make sure stores before this are seen on another CPU */
127 smp_wmb();
128 fc->initialized = 1;
129 }
130
131 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
132 {
133 return !fc->initialized || (for_background && fc->blocked);
134 }
135
136 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
137 bool for_background)
138 {
139 struct fuse_req *req;
140 int err;
141 atomic_inc(&fc->num_waiting);
142
143 if (fuse_block_alloc(fc, for_background)) {
144 err = -EINTR;
145 if (wait_event_killable_exclusive(fc->blocked_waitq,
146 !fuse_block_alloc(fc, for_background)))
147 goto out;
148 }
149 /* Matches smp_wmb() in fuse_set_initialized() */
150 smp_rmb();
151
152 err = -ENOTCONN;
153 if (!fc->connected)
154 goto out;
155
156 err = -ECONNREFUSED;
157 if (fc->conn_error)
158 goto out;
159
160 req = fuse_request_alloc(npages);
161 err = -ENOMEM;
162 if (!req) {
163 if (for_background)
164 wake_up(&fc->blocked_waitq);
165 goto out;
166 }
167
168 fuse_req_init_context(fc, req);
169 __set_bit(FR_WAITING, &req->flags);
170 if (for_background)
171 __set_bit(FR_BACKGROUND, &req->flags);
172
173 return req;
174
175 out:
176 atomic_dec(&fc->num_waiting);
177 return ERR_PTR(err);
178 }
179
180 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
181 {
182 return __fuse_get_req(fc, npages, false);
183 }
184 EXPORT_SYMBOL_GPL(fuse_get_req);
185
186 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
187 unsigned npages)
188 {
189 return __fuse_get_req(fc, npages, true);
190 }
191 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
192
193 /*
194 * Return request in fuse_file->reserved_req. However that may
195 * currently be in use. If that is the case, wait for it to become
196 * available.
197 */
198 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
199 struct file *file)
200 {
201 struct fuse_req *req = NULL;
202 struct fuse_file *ff = file->private_data;
203
204 do {
205 wait_event(fc->reserved_req_waitq, ff->reserved_req);
206 spin_lock(&fc->lock);
207 if (ff->reserved_req) {
208 req = ff->reserved_req;
209 ff->reserved_req = NULL;
210 req->stolen_file = get_file(file);
211 }
212 spin_unlock(&fc->lock);
213 } while (!req);
214
215 return req;
216 }
217
218 /*
219 * Put stolen request back into fuse_file->reserved_req
220 */
221 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
222 {
223 struct file *file = req->stolen_file;
224 struct fuse_file *ff = file->private_data;
225
226 spin_lock(&fc->lock);
227 fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
228 BUG_ON(ff->reserved_req);
229 ff->reserved_req = req;
230 wake_up_all(&fc->reserved_req_waitq);
231 spin_unlock(&fc->lock);
232 fput(file);
233 }
234
235 /*
236 * Gets a requests for a file operation, always succeeds
237 *
238 * This is used for sending the FLUSH request, which must get to
239 * userspace, due to POSIX locks which may need to be unlocked.
240 *
241 * If allocation fails due to OOM, use the reserved request in
242 * fuse_file.
243 *
244 * This is very unlikely to deadlock accidentally, since the
245 * filesystem should not have it's own file open. If deadlock is
246 * intentional, it can still be broken by "aborting" the filesystem.
247 */
248 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
249 struct file *file)
250 {
251 struct fuse_req *req;
252
253 atomic_inc(&fc->num_waiting);
254 wait_event(fc->blocked_waitq, fc->initialized);
255 /* Matches smp_wmb() in fuse_set_initialized() */
256 smp_rmb();
257 req = fuse_request_alloc(0);
258 if (!req)
259 req = get_reserved_req(fc, file);
260
261 fuse_req_init_context(fc, req);
262 __set_bit(FR_WAITING, &req->flags);
263 __clear_bit(FR_BACKGROUND, &req->flags);
264 return req;
265 }
266
267 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
268 {
269 if (refcount_dec_and_test(&req->count)) {
270 if (test_bit(FR_BACKGROUND, &req->flags)) {
271 /*
272 * We get here in the unlikely case that a background
273 * request was allocated but not sent
274 */
275 spin_lock(&fc->lock);
276 if (!fc->blocked)
277 wake_up(&fc->blocked_waitq);
278 spin_unlock(&fc->lock);
279 }
280
281 if (test_bit(FR_WAITING, &req->flags)) {
282 __clear_bit(FR_WAITING, &req->flags);
283 atomic_dec(&fc->num_waiting);
284 }
285
286 if (req->stolen_file)
287 put_reserved_req(fc, req);
288 else
289 fuse_request_free(req);
290 }
291 }
292 EXPORT_SYMBOL_GPL(fuse_put_request);
293
294 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
295 {
296 unsigned nbytes = 0;
297 unsigned i;
298
299 for (i = 0; i < numargs; i++)
300 nbytes += args[i].size;
301
302 return nbytes;
303 }
304
305 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
306 {
307 return ++fiq->reqctr;
308 }
309
310 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
311 {
312 req->in.h.len = sizeof(struct fuse_in_header) +
313 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
314 list_add_tail(&req->list, &fiq->pending);
315 wake_up_locked(&fiq->waitq);
316 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
317 }
318
319 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
320 u64 nodeid, u64 nlookup)
321 {
322 struct fuse_iqueue *fiq = &fc->iq;
323
324 forget->forget_one.nodeid = nodeid;
325 forget->forget_one.nlookup = nlookup;
326
327 spin_lock(&fiq->waitq.lock);
328 if (fiq->connected) {
329 fiq->forget_list_tail->next = forget;
330 fiq->forget_list_tail = forget;
331 wake_up_locked(&fiq->waitq);
332 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
333 } else {
334 kfree(forget);
335 }
336 spin_unlock(&fiq->waitq.lock);
337 }
338
339 static void flush_bg_queue(struct fuse_conn *fc)
340 {
341 while (fc->active_background < fc->max_background &&
342 !list_empty(&fc->bg_queue)) {
343 struct fuse_req *req;
344 struct fuse_iqueue *fiq = &fc->iq;
345
346 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
347 list_del(&req->list);
348 fc->active_background++;
349 spin_lock(&fiq->waitq.lock);
350 req->in.h.unique = fuse_get_unique(fiq);
351 queue_request(fiq, req);
352 spin_unlock(&fiq->waitq.lock);
353 }
354 }
355
356 /*
357 * This function is called when a request is finished. Either a reply
358 * has arrived or it was aborted (and not yet sent) or some error
359 * occurred during communication with userspace, or the device file
360 * was closed. The requester thread is woken up (if still waiting),
361 * the 'end' callback is called if given, else the reference to the
362 * request is released
363 */
364 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
365 {
366 struct fuse_iqueue *fiq = &fc->iq;
367
368 if (test_and_set_bit(FR_FINISHED, &req->flags))
369 return;
370
371 spin_lock(&fiq->waitq.lock);
372 list_del_init(&req->intr_entry);
373 spin_unlock(&fiq->waitq.lock);
374 WARN_ON(test_bit(FR_PENDING, &req->flags));
375 WARN_ON(test_bit(FR_SENT, &req->flags));
376 if (test_bit(FR_BACKGROUND, &req->flags)) {
377 spin_lock(&fc->lock);
378 clear_bit(FR_BACKGROUND, &req->flags);
379 if (fc->num_background == fc->max_background)
380 fc->blocked = 0;
381
382 /* Wake up next waiter, if any */
383 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
384 wake_up(&fc->blocked_waitq);
385
386 if (fc->num_background == fc->congestion_threshold &&
387 fc->connected && fc->sb) {
388 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
389 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
390 }
391 fc->num_background--;
392 fc->active_background--;
393 flush_bg_queue(fc);
394 spin_unlock(&fc->lock);
395 }
396 wake_up(&req->waitq);
397 if (req->end)
398 req->end(fc, req);
399 fuse_put_request(fc, req);
400 }
401
402 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
403 {
404 spin_lock(&fiq->waitq.lock);
405 if (test_bit(FR_FINISHED, &req->flags)) {
406 spin_unlock(&fiq->waitq.lock);
407 return;
408 }
409 if (list_empty(&req->intr_entry)) {
410 list_add_tail(&req->intr_entry, &fiq->interrupts);
411 wake_up_locked(&fiq->waitq);
412 }
413 spin_unlock(&fiq->waitq.lock);
414 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
415 }
416
417 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
418 {
419 struct fuse_iqueue *fiq = &fc->iq;
420 int err;
421
422 if (!fc->no_interrupt) {
423 /* Any signal may interrupt this */
424 err = wait_event_interruptible(req->waitq,
425 test_bit(FR_FINISHED, &req->flags));
426 if (!err)
427 return;
428
429 set_bit(FR_INTERRUPTED, &req->flags);
430 /* matches barrier in fuse_dev_do_read() */
431 smp_mb__after_atomic();
432 if (test_bit(FR_SENT, &req->flags))
433 queue_interrupt(fiq, req);
434 }
435
436 if (!test_bit(FR_FORCE, &req->flags)) {
437 /* Only fatal signals may interrupt this */
438 err = wait_event_killable(req->waitq,
439 test_bit(FR_FINISHED, &req->flags));
440 if (!err)
441 return;
442
443 spin_lock(&fiq->waitq.lock);
444 /* Request is not yet in userspace, bail out */
445 if (test_bit(FR_PENDING, &req->flags)) {
446 list_del(&req->list);
447 spin_unlock(&fiq->waitq.lock);
448 __fuse_put_request(req);
449 req->out.h.error = -EINTR;
450 return;
451 }
452 spin_unlock(&fiq->waitq.lock);
453 }
454
455 /*
456 * Either request is already in userspace, or it was forced.
457 * Wait it out.
458 */
459 while (!test_bit(FR_FINISHED, &req->flags))
460 wait_event_freezable(req->waitq,
461 test_bit(FR_FINISHED, &req->flags));
462 }
463
464 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
465 {
466 struct fuse_iqueue *fiq = &fc->iq;
467
468 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
469 spin_lock(&fiq->waitq.lock);
470 if (!fiq->connected) {
471 spin_unlock(&fiq->waitq.lock);
472 req->out.h.error = -ENOTCONN;
473 } else {
474 req->in.h.unique = fuse_get_unique(fiq);
475 queue_request(fiq, req);
476 /* acquire extra reference, since request is still needed
477 after request_end() */
478 __fuse_get_request(req);
479 spin_unlock(&fiq->waitq.lock);
480
481 request_wait_answer(fc, req);
482 /* Pairs with smp_wmb() in request_end() */
483 smp_rmb();
484 }
485 }
486
487 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
488 {
489 __set_bit(FR_ISREPLY, &req->flags);
490 if (!test_bit(FR_WAITING, &req->flags)) {
491 __set_bit(FR_WAITING, &req->flags);
492 atomic_inc(&fc->num_waiting);
493 }
494 __fuse_request_send(fc, req);
495 }
496 EXPORT_SYMBOL_GPL(fuse_request_send);
497
498 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
499 {
500 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
501 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
502
503 if (fc->minor < 9) {
504 switch (args->in.h.opcode) {
505 case FUSE_LOOKUP:
506 case FUSE_CREATE:
507 case FUSE_MKNOD:
508 case FUSE_MKDIR:
509 case FUSE_SYMLINK:
510 case FUSE_LINK:
511 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
512 break;
513 case FUSE_GETATTR:
514 case FUSE_SETATTR:
515 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
516 break;
517 }
518 }
519 if (fc->minor < 12) {
520 switch (args->in.h.opcode) {
521 case FUSE_CREATE:
522 args->in.args[0].size = sizeof(struct fuse_open_in);
523 break;
524 case FUSE_MKNOD:
525 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
526 break;
527 }
528 }
529 }
530
531 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
532 {
533 struct fuse_req *req;
534 ssize_t ret;
535
536 req = fuse_get_req(fc, 0);
537 if (IS_ERR(req))
538 return PTR_ERR(req);
539
540 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
541 fuse_adjust_compat(fc, args);
542
543 req->in.h.opcode = args->in.h.opcode;
544 req->in.h.nodeid = args->in.h.nodeid;
545 req->in.numargs = args->in.numargs;
546 memcpy(req->in.args, args->in.args,
547 args->in.numargs * sizeof(struct fuse_in_arg));
548 req->out.argvar = args->out.argvar;
549 req->out.numargs = args->out.numargs;
550 memcpy(req->out.args, args->out.args,
551 args->out.numargs * sizeof(struct fuse_arg));
552 fuse_request_send(fc, req);
553 ret = req->out.h.error;
554 if (!ret && args->out.argvar) {
555 BUG_ON(args->out.numargs != 1);
556 ret = req->out.args[0].size;
557 }
558 fuse_put_request(fc, req);
559
560 return ret;
561 }
562
563 /*
564 * Called under fc->lock
565 *
566 * fc->connected must have been checked previously
567 */
568 void fuse_request_send_background_locked(struct fuse_conn *fc,
569 struct fuse_req *req)
570 {
571 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
572 if (!test_bit(FR_WAITING, &req->flags)) {
573 __set_bit(FR_WAITING, &req->flags);
574 atomic_inc(&fc->num_waiting);
575 }
576 __set_bit(FR_ISREPLY, &req->flags);
577 fc->num_background++;
578 if (fc->num_background == fc->max_background)
579 fc->blocked = 1;
580 if (fc->num_background == fc->congestion_threshold && fc->sb) {
581 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
582 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
583 }
584 list_add_tail(&req->list, &fc->bg_queue);
585 flush_bg_queue(fc);
586 }
587
588 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
589 {
590 BUG_ON(!req->end);
591 spin_lock(&fc->lock);
592 if (fc->connected) {
593 fuse_request_send_background_locked(fc, req);
594 spin_unlock(&fc->lock);
595 } else {
596 spin_unlock(&fc->lock);
597 req->out.h.error = -ENOTCONN;
598 req->end(fc, req);
599 fuse_put_request(fc, req);
600 }
601 }
602 EXPORT_SYMBOL_GPL(fuse_request_send_background);
603
604 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
605 struct fuse_req *req, u64 unique)
606 {
607 int err = -ENODEV;
608 struct fuse_iqueue *fiq = &fc->iq;
609
610 __clear_bit(FR_ISREPLY, &req->flags);
611 req->in.h.unique = unique;
612 spin_lock(&fiq->waitq.lock);
613 if (fiq->connected) {
614 queue_request(fiq, req);
615 err = 0;
616 }
617 spin_unlock(&fiq->waitq.lock);
618
619 return err;
620 }
621
622 void fuse_force_forget(struct file *file, u64 nodeid)
623 {
624 struct inode *inode = file_inode(file);
625 struct fuse_conn *fc = get_fuse_conn(inode);
626 struct fuse_req *req;
627 struct fuse_forget_in inarg;
628
629 memset(&inarg, 0, sizeof(inarg));
630 inarg.nlookup = 1;
631 req = fuse_get_req_nofail_nopages(fc, file);
632 req->in.h.opcode = FUSE_FORGET;
633 req->in.h.nodeid = nodeid;
634 req->in.numargs = 1;
635 req->in.args[0].size = sizeof(inarg);
636 req->in.args[0].value = &inarg;
637 __clear_bit(FR_ISREPLY, &req->flags);
638 __fuse_request_send(fc, req);
639 /* ignore errors */
640 fuse_put_request(fc, req);
641 }
642
643 /*
644 * Lock the request. Up to the next unlock_request() there mustn't be
645 * anything that could cause a page-fault. If the request was already
646 * aborted bail out.
647 */
648 static int lock_request(struct fuse_req *req)
649 {
650 int err = 0;
651 if (req) {
652 spin_lock(&req->waitq.lock);
653 if (test_bit(FR_ABORTED, &req->flags))
654 err = -ENOENT;
655 else
656 set_bit(FR_LOCKED, &req->flags);
657 spin_unlock(&req->waitq.lock);
658 }
659 return err;
660 }
661
662 /*
663 * Unlock request. If it was aborted while locked, caller is responsible
664 * for unlocking and ending the request.
665 */
666 static int unlock_request(struct fuse_req *req)
667 {
668 int err = 0;
669 if (req) {
670 spin_lock(&req->waitq.lock);
671 if (test_bit(FR_ABORTED, &req->flags))
672 err = -ENOENT;
673 else
674 clear_bit(FR_LOCKED, &req->flags);
675 spin_unlock(&req->waitq.lock);
676 }
677 return err;
678 }
679
680 struct fuse_copy_state {
681 int write;
682 struct fuse_req *req;
683 struct iov_iter *iter;
684 struct pipe_buffer *pipebufs;
685 struct pipe_buffer *currbuf;
686 struct pipe_inode_info *pipe;
687 unsigned long nr_segs;
688 struct page *pg;
689 unsigned len;
690 unsigned offset;
691 unsigned move_pages:1;
692 };
693
694 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
695 struct iov_iter *iter)
696 {
697 memset(cs, 0, sizeof(*cs));
698 cs->write = write;
699 cs->iter = iter;
700 }
701
702 /* Unmap and put previous page of userspace buffer */
703 static void fuse_copy_finish(struct fuse_copy_state *cs)
704 {
705 if (cs->currbuf) {
706 struct pipe_buffer *buf = cs->currbuf;
707
708 if (cs->write)
709 buf->len = PAGE_SIZE - cs->len;
710 cs->currbuf = NULL;
711 } else if (cs->pg) {
712 if (cs->write) {
713 flush_dcache_page(cs->pg);
714 set_page_dirty_lock(cs->pg);
715 }
716 put_page(cs->pg);
717 }
718 cs->pg = NULL;
719 }
720
721 /*
722 * Get another pagefull of userspace buffer, and map it to kernel
723 * address space, and lock request
724 */
725 static int fuse_copy_fill(struct fuse_copy_state *cs)
726 {
727 struct page *page;
728 int err;
729
730 err = unlock_request(cs->req);
731 if (err)
732 return err;
733
734 fuse_copy_finish(cs);
735 if (cs->pipebufs) {
736 struct pipe_buffer *buf = cs->pipebufs;
737
738 if (!cs->write) {
739 err = pipe_buf_confirm(cs->pipe, buf);
740 if (err)
741 return err;
742
743 BUG_ON(!cs->nr_segs);
744 cs->currbuf = buf;
745 cs->pg = buf->page;
746 cs->offset = buf->offset;
747 cs->len = buf->len;
748 cs->pipebufs++;
749 cs->nr_segs--;
750 } else {
751 if (cs->nr_segs == cs->pipe->buffers)
752 return -EIO;
753
754 page = alloc_page(GFP_HIGHUSER);
755 if (!page)
756 return -ENOMEM;
757
758 buf->page = page;
759 buf->offset = 0;
760 buf->len = 0;
761
762 cs->currbuf = buf;
763 cs->pg = page;
764 cs->offset = 0;
765 cs->len = PAGE_SIZE;
766 cs->pipebufs++;
767 cs->nr_segs++;
768 }
769 } else {
770 size_t off;
771 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
772 if (err < 0)
773 return err;
774 BUG_ON(!err);
775 cs->len = err;
776 cs->offset = off;
777 cs->pg = page;
778 iov_iter_advance(cs->iter, err);
779 }
780
781 return lock_request(cs->req);
782 }
783
784 /* Do as much copy to/from userspace buffer as we can */
785 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
786 {
787 unsigned ncpy = min(*size, cs->len);
788 if (val) {
789 void *pgaddr = kmap_atomic(cs->pg);
790 void *buf = pgaddr + cs->offset;
791
792 if (cs->write)
793 memcpy(buf, *val, ncpy);
794 else
795 memcpy(*val, buf, ncpy);
796
797 kunmap_atomic(pgaddr);
798 *val += ncpy;
799 }
800 *size -= ncpy;
801 cs->len -= ncpy;
802 cs->offset += ncpy;
803 return ncpy;
804 }
805
806 static int fuse_check_page(struct page *page)
807 {
808 if (page_mapcount(page) ||
809 page->mapping != NULL ||
810 page_count(page) != 1 ||
811 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
812 ~(1 << PG_locked |
813 1 << PG_referenced |
814 1 << PG_uptodate |
815 1 << PG_lru |
816 1 << PG_active |
817 1 << PG_reclaim))) {
818 printk(KERN_WARNING "fuse: trying to steal weird page\n");
819 printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
820 return 1;
821 }
822 return 0;
823 }
824
825 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
826 {
827 int err;
828 struct page *oldpage = *pagep;
829 struct page *newpage;
830 struct pipe_buffer *buf = cs->pipebufs;
831
832 err = unlock_request(cs->req);
833 if (err)
834 return err;
835
836 fuse_copy_finish(cs);
837
838 err = pipe_buf_confirm(cs->pipe, buf);
839 if (err)
840 return err;
841
842 BUG_ON(!cs->nr_segs);
843 cs->currbuf = buf;
844 cs->len = buf->len;
845 cs->pipebufs++;
846 cs->nr_segs--;
847
848 if (cs->len != PAGE_SIZE)
849 goto out_fallback;
850
851 if (pipe_buf_steal(cs->pipe, buf) != 0)
852 goto out_fallback;
853
854 newpage = buf->page;
855
856 if (!PageUptodate(newpage))
857 SetPageUptodate(newpage);
858
859 ClearPageMappedToDisk(newpage);
860
861 if (fuse_check_page(newpage) != 0)
862 goto out_fallback_unlock;
863
864 /*
865 * This is a new and locked page, it shouldn't be mapped or
866 * have any special flags on it
867 */
868 if (WARN_ON(page_mapped(oldpage)))
869 goto out_fallback_unlock;
870 if (WARN_ON(page_has_private(oldpage)))
871 goto out_fallback_unlock;
872 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
873 goto out_fallback_unlock;
874 if (WARN_ON(PageMlocked(oldpage)))
875 goto out_fallback_unlock;
876
877 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
878 if (err) {
879 unlock_page(newpage);
880 return err;
881 }
882
883 get_page(newpage);
884
885 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
886 lru_cache_add_file(newpage);
887
888 err = 0;
889 spin_lock(&cs->req->waitq.lock);
890 if (test_bit(FR_ABORTED, &cs->req->flags))
891 err = -ENOENT;
892 else
893 *pagep = newpage;
894 spin_unlock(&cs->req->waitq.lock);
895
896 if (err) {
897 unlock_page(newpage);
898 put_page(newpage);
899 return err;
900 }
901
902 unlock_page(oldpage);
903 put_page(oldpage);
904 cs->len = 0;
905
906 return 0;
907
908 out_fallback_unlock:
909 unlock_page(newpage);
910 out_fallback:
911 cs->pg = buf->page;
912 cs->offset = buf->offset;
913
914 err = lock_request(cs->req);
915 if (err)
916 return err;
917
918 return 1;
919 }
920
921 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
922 unsigned offset, unsigned count)
923 {
924 struct pipe_buffer *buf;
925 int err;
926
927 if (cs->nr_segs == cs->pipe->buffers)
928 return -EIO;
929
930 err = unlock_request(cs->req);
931 if (err)
932 return err;
933
934 fuse_copy_finish(cs);
935
936 buf = cs->pipebufs;
937 get_page(page);
938 buf->page = page;
939 buf->offset = offset;
940 buf->len = count;
941
942 cs->pipebufs++;
943 cs->nr_segs++;
944 cs->len = 0;
945
946 return 0;
947 }
948
949 /*
950 * Copy a page in the request to/from the userspace buffer. Must be
951 * done atomically
952 */
953 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
954 unsigned offset, unsigned count, int zeroing)
955 {
956 int err;
957 struct page *page = *pagep;
958
959 if (page && zeroing && count < PAGE_SIZE)
960 clear_highpage(page);
961
962 while (count) {
963 if (cs->write && cs->pipebufs && page) {
964 return fuse_ref_page(cs, page, offset, count);
965 } else if (!cs->len) {
966 if (cs->move_pages && page &&
967 offset == 0 && count == PAGE_SIZE) {
968 err = fuse_try_move_page(cs, pagep);
969 if (err <= 0)
970 return err;
971 } else {
972 err = fuse_copy_fill(cs);
973 if (err)
974 return err;
975 }
976 }
977 if (page) {
978 void *mapaddr = kmap_atomic(page);
979 void *buf = mapaddr + offset;
980 offset += fuse_copy_do(cs, &buf, &count);
981 kunmap_atomic(mapaddr);
982 } else
983 offset += fuse_copy_do(cs, NULL, &count);
984 }
985 if (page && !cs->write)
986 flush_dcache_page(page);
987 return 0;
988 }
989
990 /* Copy pages in the request to/from userspace buffer */
991 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
992 int zeroing)
993 {
994 unsigned i;
995 struct fuse_req *req = cs->req;
996
997 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
998 int err;
999 unsigned offset = req->page_descs[i].offset;
1000 unsigned count = min(nbytes, req->page_descs[i].length);
1001
1002 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1003 zeroing);
1004 if (err)
1005 return err;
1006
1007 nbytes -= count;
1008 }
1009 return 0;
1010 }
1011
1012 /* Copy a single argument in the request to/from userspace buffer */
1013 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1014 {
1015 while (size) {
1016 if (!cs->len) {
1017 int err = fuse_copy_fill(cs);
1018 if (err)
1019 return err;
1020 }
1021 fuse_copy_do(cs, &val, &size);
1022 }
1023 return 0;
1024 }
1025
1026 /* Copy request arguments to/from userspace buffer */
1027 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1028 unsigned argpages, struct fuse_arg *args,
1029 int zeroing)
1030 {
1031 int err = 0;
1032 unsigned i;
1033
1034 for (i = 0; !err && i < numargs; i++) {
1035 struct fuse_arg *arg = &args[i];
1036 if (i == numargs - 1 && argpages)
1037 err = fuse_copy_pages(cs, arg->size, zeroing);
1038 else
1039 err = fuse_copy_one(cs, arg->value, arg->size);
1040 }
1041 return err;
1042 }
1043
1044 static int forget_pending(struct fuse_iqueue *fiq)
1045 {
1046 return fiq->forget_list_head.next != NULL;
1047 }
1048
1049 static int request_pending(struct fuse_iqueue *fiq)
1050 {
1051 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1052 forget_pending(fiq);
1053 }
1054
1055 /*
1056 * Transfer an interrupt request to userspace
1057 *
1058 * Unlike other requests this is assembled on demand, without a need
1059 * to allocate a separate fuse_req structure.
1060 *
1061 * Called with fiq->waitq.lock held, releases it
1062 */
1063 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1064 struct fuse_copy_state *cs,
1065 size_t nbytes, struct fuse_req *req)
1066 __releases(fiq->waitq.lock)
1067 {
1068 struct fuse_in_header ih;
1069 struct fuse_interrupt_in arg;
1070 unsigned reqsize = sizeof(ih) + sizeof(arg);
1071 int err;
1072
1073 list_del_init(&req->intr_entry);
1074 req->intr_unique = fuse_get_unique(fiq);
1075 memset(&ih, 0, sizeof(ih));
1076 memset(&arg, 0, sizeof(arg));
1077 ih.len = reqsize;
1078 ih.opcode = FUSE_INTERRUPT;
1079 ih.unique = req->intr_unique;
1080 arg.unique = req->in.h.unique;
1081
1082 spin_unlock(&fiq->waitq.lock);
1083 if (nbytes < reqsize)
1084 return -EINVAL;
1085
1086 err = fuse_copy_one(cs, &ih, sizeof(ih));
1087 if (!err)
1088 err = fuse_copy_one(cs, &arg, sizeof(arg));
1089 fuse_copy_finish(cs);
1090
1091 return err ? err : reqsize;
1092 }
1093
1094 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1095 unsigned max,
1096 unsigned *countp)
1097 {
1098 struct fuse_forget_link *head = fiq->forget_list_head.next;
1099 struct fuse_forget_link **newhead = &head;
1100 unsigned count;
1101
1102 for (count = 0; *newhead != NULL && count < max; count++)
1103 newhead = &(*newhead)->next;
1104
1105 fiq->forget_list_head.next = *newhead;
1106 *newhead = NULL;
1107 if (fiq->forget_list_head.next == NULL)
1108 fiq->forget_list_tail = &fiq->forget_list_head;
1109
1110 if (countp != NULL)
1111 *countp = count;
1112
1113 return head;
1114 }
1115
1116 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1117 struct fuse_copy_state *cs,
1118 size_t nbytes)
1119 __releases(fiq->waitq.lock)
1120 {
1121 int err;
1122 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1123 struct fuse_forget_in arg = {
1124 .nlookup = forget->forget_one.nlookup,
1125 };
1126 struct fuse_in_header ih = {
1127 .opcode = FUSE_FORGET,
1128 .nodeid = forget->forget_one.nodeid,
1129 .unique = fuse_get_unique(fiq),
1130 .len = sizeof(ih) + sizeof(arg),
1131 };
1132
1133 spin_unlock(&fiq->waitq.lock);
1134 kfree(forget);
1135 if (nbytes < ih.len)
1136 return -EINVAL;
1137
1138 err = fuse_copy_one(cs, &ih, sizeof(ih));
1139 if (!err)
1140 err = fuse_copy_one(cs, &arg, sizeof(arg));
1141 fuse_copy_finish(cs);
1142
1143 if (err)
1144 return err;
1145
1146 return ih.len;
1147 }
1148
1149 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1150 struct fuse_copy_state *cs, size_t nbytes)
1151 __releases(fiq->waitq.lock)
1152 {
1153 int err;
1154 unsigned max_forgets;
1155 unsigned count;
1156 struct fuse_forget_link *head;
1157 struct fuse_batch_forget_in arg = { .count = 0 };
1158 struct fuse_in_header ih = {
1159 .opcode = FUSE_BATCH_FORGET,
1160 .unique = fuse_get_unique(fiq),
1161 .len = sizeof(ih) + sizeof(arg),
1162 };
1163
1164 if (nbytes < ih.len) {
1165 spin_unlock(&fiq->waitq.lock);
1166 return -EINVAL;
1167 }
1168
1169 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1170 head = dequeue_forget(fiq, max_forgets, &count);
1171 spin_unlock(&fiq->waitq.lock);
1172
1173 arg.count = count;
1174 ih.len += count * sizeof(struct fuse_forget_one);
1175 err = fuse_copy_one(cs, &ih, sizeof(ih));
1176 if (!err)
1177 err = fuse_copy_one(cs, &arg, sizeof(arg));
1178
1179 while (head) {
1180 struct fuse_forget_link *forget = head;
1181
1182 if (!err) {
1183 err = fuse_copy_one(cs, &forget->forget_one,
1184 sizeof(forget->forget_one));
1185 }
1186 head = forget->next;
1187 kfree(forget);
1188 }
1189
1190 fuse_copy_finish(cs);
1191
1192 if (err)
1193 return err;
1194
1195 return ih.len;
1196 }
1197
1198 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1199 struct fuse_copy_state *cs,
1200 size_t nbytes)
1201 __releases(fiq->waitq.lock)
1202 {
1203 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1204 return fuse_read_single_forget(fiq, cs, nbytes);
1205 else
1206 return fuse_read_batch_forget(fiq, cs, nbytes);
1207 }
1208
1209 /*
1210 * Read a single request into the userspace filesystem's buffer. This
1211 * function waits until a request is available, then removes it from
1212 * the pending list and copies request data to userspace buffer. If
1213 * no reply is needed (FORGET) or request has been aborted or there
1214 * was an error during the copying then it's finished by calling
1215 * request_end(). Otherwise add it to the processing list, and set
1216 * the 'sent' flag.
1217 */
1218 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1219 struct fuse_copy_state *cs, size_t nbytes)
1220 {
1221 ssize_t err;
1222 struct fuse_conn *fc = fud->fc;
1223 struct fuse_iqueue *fiq = &fc->iq;
1224 struct fuse_pqueue *fpq = &fud->pq;
1225 struct fuse_req *req;
1226 struct fuse_in *in;
1227 unsigned reqsize;
1228
1229 restart:
1230 spin_lock(&fiq->waitq.lock);
1231 err = -EAGAIN;
1232 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1233 !request_pending(fiq))
1234 goto err_unlock;
1235
1236 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1237 !fiq->connected || request_pending(fiq));
1238 if (err)
1239 goto err_unlock;
1240
1241 err = -ENODEV;
1242 if (!fiq->connected)
1243 goto err_unlock;
1244
1245 if (!list_empty(&fiq->interrupts)) {
1246 req = list_entry(fiq->interrupts.next, struct fuse_req,
1247 intr_entry);
1248 return fuse_read_interrupt(fiq, cs, nbytes, req);
1249 }
1250
1251 if (forget_pending(fiq)) {
1252 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1253 return fuse_read_forget(fc, fiq, cs, nbytes);
1254
1255 if (fiq->forget_batch <= -8)
1256 fiq->forget_batch = 16;
1257 }
1258
1259 req = list_entry(fiq->pending.next, struct fuse_req, list);
1260 clear_bit(FR_PENDING, &req->flags);
1261 list_del_init(&req->list);
1262 spin_unlock(&fiq->waitq.lock);
1263
1264 in = &req->in;
1265 reqsize = in->h.len;
1266
1267 if (task_active_pid_ns(current) != fc->pid_ns) {
1268 rcu_read_lock();
1269 in->h.pid = pid_vnr(find_pid_ns(in->h.pid, fc->pid_ns));
1270 rcu_read_unlock();
1271 }
1272
1273 /* If request is too large, reply with an error and restart the read */
1274 if (nbytes < reqsize) {
1275 req->out.h.error = -EIO;
1276 /* SETXATTR is special, since it may contain too large data */
1277 if (in->h.opcode == FUSE_SETXATTR)
1278 req->out.h.error = -E2BIG;
1279 request_end(fc, req);
1280 goto restart;
1281 }
1282 spin_lock(&fpq->lock);
1283 list_add(&req->list, &fpq->io);
1284 spin_unlock(&fpq->lock);
1285 cs->req = req;
1286 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1287 if (!err)
1288 err = fuse_copy_args(cs, in->numargs, in->argpages,
1289 (struct fuse_arg *) in->args, 0);
1290 fuse_copy_finish(cs);
1291 spin_lock(&fpq->lock);
1292 clear_bit(FR_LOCKED, &req->flags);
1293 if (!fpq->connected) {
1294 err = -ENODEV;
1295 goto out_end;
1296 }
1297 if (err) {
1298 req->out.h.error = -EIO;
1299 goto out_end;
1300 }
1301 if (!test_bit(FR_ISREPLY, &req->flags)) {
1302 err = reqsize;
1303 goto out_end;
1304 }
1305 list_move_tail(&req->list, &fpq->processing);
1306 spin_unlock(&fpq->lock);
1307 set_bit(FR_SENT, &req->flags);
1308 /* matches barrier in request_wait_answer() */
1309 smp_mb__after_atomic();
1310 if (test_bit(FR_INTERRUPTED, &req->flags))
1311 queue_interrupt(fiq, req);
1312
1313 return reqsize;
1314
1315 out_end:
1316 if (!test_bit(FR_PRIVATE, &req->flags))
1317 list_del_init(&req->list);
1318 spin_unlock(&fpq->lock);
1319 request_end(fc, req);
1320 return err;
1321
1322 err_unlock:
1323 spin_unlock(&fiq->waitq.lock);
1324 return err;
1325 }
1326
1327 static int fuse_dev_open(struct inode *inode, struct file *file)
1328 {
1329 /*
1330 * The fuse device's file's private_data is used to hold
1331 * the fuse_conn(ection) when it is mounted, and is used to
1332 * keep track of whether the file has been mounted already.
1333 */
1334 file->private_data = NULL;
1335 return 0;
1336 }
1337
1338 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1339 {
1340 struct fuse_copy_state cs;
1341 struct file *file = iocb->ki_filp;
1342 struct fuse_dev *fud = fuse_get_dev(file);
1343
1344 if (!fud)
1345 return -EPERM;
1346
1347 if (!iter_is_iovec(to))
1348 return -EINVAL;
1349
1350 fuse_copy_init(&cs, 1, to);
1351
1352 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1353 }
1354
1355 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1356 struct pipe_inode_info *pipe,
1357 size_t len, unsigned int flags)
1358 {
1359 int total, ret;
1360 int page_nr = 0;
1361 struct pipe_buffer *bufs;
1362 struct fuse_copy_state cs;
1363 struct fuse_dev *fud = fuse_get_dev(in);
1364
1365 if (!fud)
1366 return -EPERM;
1367
1368 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1369 if (!bufs)
1370 return -ENOMEM;
1371
1372 fuse_copy_init(&cs, 1, NULL);
1373 cs.pipebufs = bufs;
1374 cs.pipe = pipe;
1375 ret = fuse_dev_do_read(fud, in, &cs, len);
1376 if (ret < 0)
1377 goto out;
1378
1379 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1380 ret = -EIO;
1381 goto out;
1382 }
1383
1384 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1385 /*
1386 * Need to be careful about this. Having buf->ops in module
1387 * code can Oops if the buffer persists after module unload.
1388 */
1389 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1390 bufs[page_nr].flags = 0;
1391 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1392 if (unlikely(ret < 0))
1393 break;
1394 }
1395 if (total)
1396 ret = total;
1397 out:
1398 for (; page_nr < cs.nr_segs; page_nr++)
1399 put_page(bufs[page_nr].page);
1400
1401 kfree(bufs);
1402 return ret;
1403 }
1404
1405 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1406 struct fuse_copy_state *cs)
1407 {
1408 struct fuse_notify_poll_wakeup_out outarg;
1409 int err = -EINVAL;
1410
1411 if (size != sizeof(outarg))
1412 goto err;
1413
1414 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1415 if (err)
1416 goto err;
1417
1418 fuse_copy_finish(cs);
1419 return fuse_notify_poll_wakeup(fc, &outarg);
1420
1421 err:
1422 fuse_copy_finish(cs);
1423 return err;
1424 }
1425
1426 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1427 struct fuse_copy_state *cs)
1428 {
1429 struct fuse_notify_inval_inode_out outarg;
1430 int err = -EINVAL;
1431
1432 if (size != sizeof(outarg))
1433 goto err;
1434
1435 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1436 if (err)
1437 goto err;
1438 fuse_copy_finish(cs);
1439
1440 down_read(&fc->killsb);
1441 err = -ENOENT;
1442 if (fc->sb) {
1443 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1444 outarg.off, outarg.len);
1445 }
1446 up_read(&fc->killsb);
1447 return err;
1448
1449 err:
1450 fuse_copy_finish(cs);
1451 return err;
1452 }
1453
1454 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1455 struct fuse_copy_state *cs)
1456 {
1457 struct fuse_notify_inval_entry_out outarg;
1458 int err = -ENOMEM;
1459 char *buf;
1460 struct qstr name;
1461
1462 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1463 if (!buf)
1464 goto err;
1465
1466 err = -EINVAL;
1467 if (size < sizeof(outarg))
1468 goto err;
1469
1470 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1471 if (err)
1472 goto err;
1473
1474 err = -ENAMETOOLONG;
1475 if (outarg.namelen > FUSE_NAME_MAX)
1476 goto err;
1477
1478 err = -EINVAL;
1479 if (size != sizeof(outarg) + outarg.namelen + 1)
1480 goto err;
1481
1482 name.name = buf;
1483 name.len = outarg.namelen;
1484 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1485 if (err)
1486 goto err;
1487 fuse_copy_finish(cs);
1488 buf[outarg.namelen] = 0;
1489
1490 down_read(&fc->killsb);
1491 err = -ENOENT;
1492 if (fc->sb)
1493 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1494 up_read(&fc->killsb);
1495 kfree(buf);
1496 return err;
1497
1498 err:
1499 kfree(buf);
1500 fuse_copy_finish(cs);
1501 return err;
1502 }
1503
1504 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1505 struct fuse_copy_state *cs)
1506 {
1507 struct fuse_notify_delete_out outarg;
1508 int err = -ENOMEM;
1509 char *buf;
1510 struct qstr name;
1511
1512 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1513 if (!buf)
1514 goto err;
1515
1516 err = -EINVAL;
1517 if (size < sizeof(outarg))
1518 goto err;
1519
1520 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1521 if (err)
1522 goto err;
1523
1524 err = -ENAMETOOLONG;
1525 if (outarg.namelen > FUSE_NAME_MAX)
1526 goto err;
1527
1528 err = -EINVAL;
1529 if (size != sizeof(outarg) + outarg.namelen + 1)
1530 goto err;
1531
1532 name.name = buf;
1533 name.len = outarg.namelen;
1534 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1535 if (err)
1536 goto err;
1537 fuse_copy_finish(cs);
1538 buf[outarg.namelen] = 0;
1539
1540 down_read(&fc->killsb);
1541 err = -ENOENT;
1542 if (fc->sb)
1543 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1544 outarg.child, &name);
1545 up_read(&fc->killsb);
1546 kfree(buf);
1547 return err;
1548
1549 err:
1550 kfree(buf);
1551 fuse_copy_finish(cs);
1552 return err;
1553 }
1554
1555 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1556 struct fuse_copy_state *cs)
1557 {
1558 struct fuse_notify_store_out outarg;
1559 struct inode *inode;
1560 struct address_space *mapping;
1561 u64 nodeid;
1562 int err;
1563 pgoff_t index;
1564 unsigned int offset;
1565 unsigned int num;
1566 loff_t file_size;
1567 loff_t end;
1568
1569 err = -EINVAL;
1570 if (size < sizeof(outarg))
1571 goto out_finish;
1572
1573 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1574 if (err)
1575 goto out_finish;
1576
1577 err = -EINVAL;
1578 if (size - sizeof(outarg) != outarg.size)
1579 goto out_finish;
1580
1581 nodeid = outarg.nodeid;
1582
1583 down_read(&fc->killsb);
1584
1585 err = -ENOENT;
1586 if (!fc->sb)
1587 goto out_up_killsb;
1588
1589 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1590 if (!inode)
1591 goto out_up_killsb;
1592
1593 mapping = inode->i_mapping;
1594 index = outarg.offset >> PAGE_SHIFT;
1595 offset = outarg.offset & ~PAGE_MASK;
1596 file_size = i_size_read(inode);
1597 end = outarg.offset + outarg.size;
1598 if (end > file_size) {
1599 file_size = end;
1600 fuse_write_update_size(inode, file_size);
1601 }
1602
1603 num = outarg.size;
1604 while (num) {
1605 struct page *page;
1606 unsigned int this_num;
1607
1608 err = -ENOMEM;
1609 page = find_or_create_page(mapping, index,
1610 mapping_gfp_mask(mapping));
1611 if (!page)
1612 goto out_iput;
1613
1614 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1615 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1616 if (!err && offset == 0 &&
1617 (this_num == PAGE_SIZE || file_size == end))
1618 SetPageUptodate(page);
1619 unlock_page(page);
1620 put_page(page);
1621
1622 if (err)
1623 goto out_iput;
1624
1625 num -= this_num;
1626 offset = 0;
1627 index++;
1628 }
1629
1630 err = 0;
1631
1632 out_iput:
1633 iput(inode);
1634 out_up_killsb:
1635 up_read(&fc->killsb);
1636 out_finish:
1637 fuse_copy_finish(cs);
1638 return err;
1639 }
1640
1641 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1642 {
1643 release_pages(req->pages, req->num_pages, false);
1644 }
1645
1646 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1647 struct fuse_notify_retrieve_out *outarg)
1648 {
1649 int err;
1650 struct address_space *mapping = inode->i_mapping;
1651 struct fuse_req *req;
1652 pgoff_t index;
1653 loff_t file_size;
1654 unsigned int num;
1655 unsigned int offset;
1656 size_t total_len = 0;
1657 int num_pages;
1658
1659 offset = outarg->offset & ~PAGE_MASK;
1660 file_size = i_size_read(inode);
1661
1662 num = outarg->size;
1663 if (outarg->offset > file_size)
1664 num = 0;
1665 else if (outarg->offset + num > file_size)
1666 num = file_size - outarg->offset;
1667
1668 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1669 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1670
1671 req = fuse_get_req(fc, num_pages);
1672 if (IS_ERR(req))
1673 return PTR_ERR(req);
1674
1675 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1676 req->in.h.nodeid = outarg->nodeid;
1677 req->in.numargs = 2;
1678 req->in.argpages = 1;
1679 req->page_descs[0].offset = offset;
1680 req->end = fuse_retrieve_end;
1681
1682 index = outarg->offset >> PAGE_SHIFT;
1683
1684 while (num && req->num_pages < num_pages) {
1685 struct page *page;
1686 unsigned int this_num;
1687
1688 page = find_get_page(mapping, index);
1689 if (!page)
1690 break;
1691
1692 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1693 req->pages[req->num_pages] = page;
1694 req->page_descs[req->num_pages].length = this_num;
1695 req->num_pages++;
1696
1697 offset = 0;
1698 num -= this_num;
1699 total_len += this_num;
1700 index++;
1701 }
1702 req->misc.retrieve_in.offset = outarg->offset;
1703 req->misc.retrieve_in.size = total_len;
1704 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1705 req->in.args[0].value = &req->misc.retrieve_in;
1706 req->in.args[1].size = total_len;
1707
1708 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1709 if (err)
1710 fuse_retrieve_end(fc, req);
1711
1712 return err;
1713 }
1714
1715 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1716 struct fuse_copy_state *cs)
1717 {
1718 struct fuse_notify_retrieve_out outarg;
1719 struct inode *inode;
1720 int err;
1721
1722 err = -EINVAL;
1723 if (size != sizeof(outarg))
1724 goto copy_finish;
1725
1726 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1727 if (err)
1728 goto copy_finish;
1729
1730 fuse_copy_finish(cs);
1731
1732 down_read(&fc->killsb);
1733 err = -ENOENT;
1734 if (fc->sb) {
1735 u64 nodeid = outarg.nodeid;
1736
1737 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1738 if (inode) {
1739 err = fuse_retrieve(fc, inode, &outarg);
1740 iput(inode);
1741 }
1742 }
1743 up_read(&fc->killsb);
1744
1745 return err;
1746
1747 copy_finish:
1748 fuse_copy_finish(cs);
1749 return err;
1750 }
1751
1752 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1753 unsigned int size, struct fuse_copy_state *cs)
1754 {
1755 /* Don't try to move pages (yet) */
1756 cs->move_pages = 0;
1757
1758 switch (code) {
1759 case FUSE_NOTIFY_POLL:
1760 return fuse_notify_poll(fc, size, cs);
1761
1762 case FUSE_NOTIFY_INVAL_INODE:
1763 return fuse_notify_inval_inode(fc, size, cs);
1764
1765 case FUSE_NOTIFY_INVAL_ENTRY:
1766 return fuse_notify_inval_entry(fc, size, cs);
1767
1768 case FUSE_NOTIFY_STORE:
1769 return fuse_notify_store(fc, size, cs);
1770
1771 case FUSE_NOTIFY_RETRIEVE:
1772 return fuse_notify_retrieve(fc, size, cs);
1773
1774 case FUSE_NOTIFY_DELETE:
1775 return fuse_notify_delete(fc, size, cs);
1776
1777 default:
1778 fuse_copy_finish(cs);
1779 return -EINVAL;
1780 }
1781 }
1782
1783 /* Look up request on processing list by unique ID */
1784 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1785 {
1786 struct fuse_req *req;
1787
1788 list_for_each_entry(req, &fpq->processing, list) {
1789 if (req->in.h.unique == unique || req->intr_unique == unique)
1790 return req;
1791 }
1792 return NULL;
1793 }
1794
1795 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1796 unsigned nbytes)
1797 {
1798 unsigned reqsize = sizeof(struct fuse_out_header);
1799
1800 if (out->h.error)
1801 return nbytes != reqsize ? -EINVAL : 0;
1802
1803 reqsize += len_args(out->numargs, out->args);
1804
1805 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1806 return -EINVAL;
1807 else if (reqsize > nbytes) {
1808 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1809 unsigned diffsize = reqsize - nbytes;
1810 if (diffsize > lastarg->size)
1811 return -EINVAL;
1812 lastarg->size -= diffsize;
1813 }
1814 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1815 out->page_zeroing);
1816 }
1817
1818 /*
1819 * Write a single reply to a request. First the header is copied from
1820 * the write buffer. The request is then searched on the processing
1821 * list by the unique ID found in the header. If found, then remove
1822 * it from the list and copy the rest of the buffer to the request.
1823 * The request is finished by calling request_end()
1824 */
1825 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1826 struct fuse_copy_state *cs, size_t nbytes)
1827 {
1828 int err;
1829 struct fuse_conn *fc = fud->fc;
1830 struct fuse_pqueue *fpq = &fud->pq;
1831 struct fuse_req *req;
1832 struct fuse_out_header oh;
1833
1834 if (nbytes < sizeof(struct fuse_out_header))
1835 return -EINVAL;
1836
1837 err = fuse_copy_one(cs, &oh, sizeof(oh));
1838 if (err)
1839 goto err_finish;
1840
1841 err = -EINVAL;
1842 if (oh.len != nbytes)
1843 goto err_finish;
1844
1845 /*
1846 * Zero oh.unique indicates unsolicited notification message
1847 * and error contains notification code.
1848 */
1849 if (!oh.unique) {
1850 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1851 return err ? err : nbytes;
1852 }
1853
1854 err = -EINVAL;
1855 if (oh.error <= -1000 || oh.error > 0)
1856 goto err_finish;
1857
1858 spin_lock(&fpq->lock);
1859 err = -ENOENT;
1860 if (!fpq->connected)
1861 goto err_unlock_pq;
1862
1863 req = request_find(fpq, oh.unique);
1864 if (!req)
1865 goto err_unlock_pq;
1866
1867 /* Is it an interrupt reply? */
1868 if (req->intr_unique == oh.unique) {
1869 spin_unlock(&fpq->lock);
1870
1871 err = -EINVAL;
1872 if (nbytes != sizeof(struct fuse_out_header))
1873 goto err_finish;
1874
1875 if (oh.error == -ENOSYS)
1876 fc->no_interrupt = 1;
1877 else if (oh.error == -EAGAIN)
1878 queue_interrupt(&fc->iq, req);
1879
1880 fuse_copy_finish(cs);
1881 return nbytes;
1882 }
1883
1884 clear_bit(FR_SENT, &req->flags);
1885 list_move(&req->list, &fpq->io);
1886 req->out.h = oh;
1887 set_bit(FR_LOCKED, &req->flags);
1888 spin_unlock(&fpq->lock);
1889 cs->req = req;
1890 if (!req->out.page_replace)
1891 cs->move_pages = 0;
1892
1893 err = copy_out_args(cs, &req->out, nbytes);
1894 if (req->in.h.opcode == FUSE_CANONICAL_PATH) {
1895 char *path = (char *)req->out.args[0].value;
1896
1897 path[req->out.args[0].size - 1] = 0;
1898 req->out.h.error = kern_path(path, 0, req->canonical_path);
1899 }
1900 fuse_copy_finish(cs);
1901
1902 spin_lock(&fpq->lock);
1903 clear_bit(FR_LOCKED, &req->flags);
1904 if (!fpq->connected)
1905 err = -ENOENT;
1906 else if (err)
1907 req->out.h.error = -EIO;
1908 if (!test_bit(FR_PRIVATE, &req->flags))
1909 list_del_init(&req->list);
1910 spin_unlock(&fpq->lock);
1911
1912 request_end(fc, req);
1913
1914 return err ? err : nbytes;
1915
1916 err_unlock_pq:
1917 spin_unlock(&fpq->lock);
1918 err_finish:
1919 fuse_copy_finish(cs);
1920 return err;
1921 }
1922
1923 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1924 {
1925 struct fuse_copy_state cs;
1926 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1927
1928 if (!fud)
1929 return -EPERM;
1930
1931 if (!iter_is_iovec(from))
1932 return -EINVAL;
1933
1934 fuse_copy_init(&cs, 0, from);
1935
1936 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1937 }
1938
1939 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1940 struct file *out, loff_t *ppos,
1941 size_t len, unsigned int flags)
1942 {
1943 unsigned nbuf;
1944 unsigned idx;
1945 struct pipe_buffer *bufs;
1946 struct fuse_copy_state cs;
1947 struct fuse_dev *fud;
1948 size_t rem;
1949 ssize_t ret;
1950
1951 fud = fuse_get_dev(out);
1952 if (!fud)
1953 return -EPERM;
1954
1955 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1956 if (!bufs)
1957 return -ENOMEM;
1958
1959 pipe_lock(pipe);
1960 nbuf = 0;
1961 rem = 0;
1962 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1963 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1964
1965 ret = -EINVAL;
1966 if (rem < len) {
1967 pipe_unlock(pipe);
1968 goto out;
1969 }
1970
1971 rem = len;
1972 while (rem) {
1973 struct pipe_buffer *ibuf;
1974 struct pipe_buffer *obuf;
1975
1976 BUG_ON(nbuf >= pipe->buffers);
1977 BUG_ON(!pipe->nrbufs);
1978 ibuf = &pipe->bufs[pipe->curbuf];
1979 obuf = &bufs[nbuf];
1980
1981 if (rem >= ibuf->len) {
1982 *obuf = *ibuf;
1983 ibuf->ops = NULL;
1984 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1985 pipe->nrbufs--;
1986 } else {
1987 pipe_buf_get(pipe, ibuf);
1988 *obuf = *ibuf;
1989 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1990 obuf->len = rem;
1991 ibuf->offset += obuf->len;
1992 ibuf->len -= obuf->len;
1993 }
1994 nbuf++;
1995 rem -= obuf->len;
1996 }
1997 pipe_unlock(pipe);
1998
1999 fuse_copy_init(&cs, 0, NULL);
2000 cs.pipebufs = bufs;
2001 cs.nr_segs = nbuf;
2002 cs.pipe = pipe;
2003
2004 if (flags & SPLICE_F_MOVE)
2005 cs.move_pages = 1;
2006
2007 ret = fuse_dev_do_write(fud, &cs, len);
2008
2009 for (idx = 0; idx < nbuf; idx++)
2010 pipe_buf_release(pipe, &bufs[idx]);
2011
2012 out:
2013 kfree(bufs);
2014 return ret;
2015 }
2016
2017 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2018 {
2019 unsigned mask = POLLOUT | POLLWRNORM;
2020 struct fuse_iqueue *fiq;
2021 struct fuse_dev *fud = fuse_get_dev(file);
2022
2023 if (!fud)
2024 return POLLERR;
2025
2026 fiq = &fud->fc->iq;
2027 poll_wait(file, &fiq->waitq, wait);
2028
2029 spin_lock(&fiq->waitq.lock);
2030 if (!fiq->connected)
2031 mask = POLLERR;
2032 else if (request_pending(fiq))
2033 mask |= POLLIN | POLLRDNORM;
2034 spin_unlock(&fiq->waitq.lock);
2035
2036 return mask;
2037 }
2038
2039 /*
2040 * Abort all requests on the given list (pending or processing)
2041 *
2042 * This function releases and reacquires fc->lock
2043 */
2044 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2045 {
2046 while (!list_empty(head)) {
2047 struct fuse_req *req;
2048 req = list_entry(head->next, struct fuse_req, list);
2049 req->out.h.error = -ECONNABORTED;
2050 clear_bit(FR_SENT, &req->flags);
2051 list_del_init(&req->list);
2052 request_end(fc, req);
2053 }
2054 }
2055
2056 static void end_polls(struct fuse_conn *fc)
2057 {
2058 struct rb_node *p;
2059
2060 p = rb_first(&fc->polled_files);
2061
2062 while (p) {
2063 struct fuse_file *ff;
2064 ff = rb_entry(p, struct fuse_file, polled_node);
2065 wake_up_interruptible_all(&ff->poll_wait);
2066
2067 p = rb_next(p);
2068 }
2069 }
2070
2071 /*
2072 * Abort all requests.
2073 *
2074 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2075 * filesystem.
2076 *
2077 * The same effect is usually achievable through killing the filesystem daemon
2078 * and all users of the filesystem. The exception is the combination of an
2079 * asynchronous request and the tricky deadlock (see
2080 * Documentation/filesystems/fuse.txt).
2081 *
2082 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2083 * requests, they should be finished off immediately. Locked requests will be
2084 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2085 * requests. It is possible that some request will finish before we can. This
2086 * is OK, the request will in that case be removed from the list before we touch
2087 * it.
2088 */
2089 void fuse_abort_conn(struct fuse_conn *fc)
2090 {
2091 struct fuse_iqueue *fiq = &fc->iq;
2092
2093 spin_lock(&fc->lock);
2094 if (fc->connected) {
2095 struct fuse_dev *fud;
2096 struct fuse_req *req, *next;
2097 LIST_HEAD(to_end1);
2098 LIST_HEAD(to_end2);
2099
2100 fc->connected = 0;
2101 fc->blocked = 0;
2102 fuse_set_initialized(fc);
2103 list_for_each_entry(fud, &fc->devices, entry) {
2104 struct fuse_pqueue *fpq = &fud->pq;
2105
2106 spin_lock(&fpq->lock);
2107 fpq->connected = 0;
2108 list_for_each_entry_safe(req, next, &fpq->io, list) {
2109 req->out.h.error = -ECONNABORTED;
2110 spin_lock(&req->waitq.lock);
2111 set_bit(FR_ABORTED, &req->flags);
2112 if (!test_bit(FR_LOCKED, &req->flags)) {
2113 set_bit(FR_PRIVATE, &req->flags);
2114 list_move(&req->list, &to_end1);
2115 }
2116 spin_unlock(&req->waitq.lock);
2117 }
2118 list_splice_init(&fpq->processing, &to_end2);
2119 spin_unlock(&fpq->lock);
2120 }
2121 fc->max_background = UINT_MAX;
2122 flush_bg_queue(fc);
2123
2124 spin_lock(&fiq->waitq.lock);
2125 fiq->connected = 0;
2126 list_splice_init(&fiq->pending, &to_end2);
2127 list_for_each_entry(req, &to_end2, list)
2128 clear_bit(FR_PENDING, &req->flags);
2129 while (forget_pending(fiq))
2130 kfree(dequeue_forget(fiq, 1, NULL));
2131 wake_up_all_locked(&fiq->waitq);
2132 spin_unlock(&fiq->waitq.lock);
2133 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2134 end_polls(fc);
2135 wake_up_all(&fc->blocked_waitq);
2136 spin_unlock(&fc->lock);
2137
2138 while (!list_empty(&to_end1)) {
2139 req = list_first_entry(&to_end1, struct fuse_req, list);
2140 __fuse_get_request(req);
2141 list_del_init(&req->list);
2142 request_end(fc, req);
2143 }
2144 end_requests(fc, &to_end2);
2145 } else {
2146 spin_unlock(&fc->lock);
2147 }
2148 }
2149 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2150
2151 int fuse_dev_release(struct inode *inode, struct file *file)
2152 {
2153 struct fuse_dev *fud = fuse_get_dev(file);
2154
2155 if (fud) {
2156 struct fuse_conn *fc = fud->fc;
2157 struct fuse_pqueue *fpq = &fud->pq;
2158
2159 WARN_ON(!list_empty(&fpq->io));
2160 end_requests(fc, &fpq->processing);
2161 /* Are we the last open device? */
2162 if (atomic_dec_and_test(&fc->dev_count)) {
2163 WARN_ON(fc->iq.fasync != NULL);
2164 fuse_abort_conn(fc);
2165 }
2166 fuse_dev_free(fud);
2167 }
2168 return 0;
2169 }
2170 EXPORT_SYMBOL_GPL(fuse_dev_release);
2171
2172 static int fuse_dev_fasync(int fd, struct file *file, int on)
2173 {
2174 struct fuse_dev *fud = fuse_get_dev(file);
2175
2176 if (!fud)
2177 return -EPERM;
2178
2179 /* No locking - fasync_helper does its own locking */
2180 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2181 }
2182
2183 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2184 {
2185 struct fuse_dev *fud;
2186
2187 if (new->private_data)
2188 return -EINVAL;
2189
2190 fud = fuse_dev_alloc(fc);
2191 if (!fud)
2192 return -ENOMEM;
2193
2194 new->private_data = fud;
2195 atomic_inc(&fc->dev_count);
2196
2197 return 0;
2198 }
2199
2200 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2201 unsigned long arg)
2202 {
2203 int err = -ENOTTY;
2204
2205 if (cmd == FUSE_DEV_IOC_CLONE) {
2206 int oldfd;
2207
2208 err = -EFAULT;
2209 if (!get_user(oldfd, (__u32 __user *) arg)) {
2210 struct file *old = fget(oldfd);
2211
2212 err = -EINVAL;
2213 if (old) {
2214 struct fuse_dev *fud = NULL;
2215
2216 /*
2217 * Check against file->f_op because CUSE
2218 * uses the same ioctl handler.
2219 */
2220 if (old->f_op == file->f_op &&
2221 old->f_cred->user_ns == file->f_cred->user_ns)
2222 fud = fuse_get_dev(old);
2223
2224 if (fud) {
2225 mutex_lock(&fuse_mutex);
2226 err = fuse_device_clone(fud->fc, file);
2227 mutex_unlock(&fuse_mutex);
2228 }
2229 fput(old);
2230 }
2231 }
2232 }
2233 return err;
2234 }
2235
2236 const struct file_operations fuse_dev_operations = {
2237 .owner = THIS_MODULE,
2238 .open = fuse_dev_open,
2239 .llseek = no_llseek,
2240 .read_iter = fuse_dev_read,
2241 .splice_read = fuse_dev_splice_read,
2242 .write_iter = fuse_dev_write,
2243 .splice_write = fuse_dev_splice_write,
2244 .poll = fuse_dev_poll,
2245 .release = fuse_dev_release,
2246 .fasync = fuse_dev_fasync,
2247 .unlocked_ioctl = fuse_dev_ioctl,
2248 .compat_ioctl = fuse_dev_ioctl,
2249 };
2250 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2251
2252 static struct miscdevice fuse_miscdevice = {
2253 .minor = FUSE_MINOR,
2254 .name = "fuse",
2255 .fops = &fuse_dev_operations,
2256 };
2257
2258 int __init fuse_dev_init(void)
2259 {
2260 int err = -ENOMEM;
2261 fuse_req_cachep = kmem_cache_create("fuse_request",
2262 sizeof(struct fuse_req),
2263 0, 0, NULL);
2264 if (!fuse_req_cachep)
2265 goto out;
2266
2267 err = misc_register(&fuse_miscdevice);
2268 if (err)
2269 goto out_cache_clean;
2270
2271 return 0;
2272
2273 out_cache_clean:
2274 kmem_cache_destroy(fuse_req_cachep);
2275 out:
2276 return err;
2277 }
2278
2279 void fuse_dev_cleanup(void)
2280 {
2281 misc_deregister(&fuse_miscdevice);
2282 kmem_cache_destroy(fuse_req_cachep);
2283 }