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