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