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