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[mirror_ubuntu-zesty-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 #include <linux/sched.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_conn *fc, 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 = pid_nr_ns(task_pid(current), fc->pid_ns);
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(fc, 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(fc, 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 if (task_active_pid_ns(current) != fc->pid_ns)
1227 return -EIO;
1228
1229 restart:
1230 spin_lock(&fiq->waitq.lock);
1231 err = -EAGAIN;
1232 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1233 !request_pending(fiq))
1234 goto err_unlock;
1235
1236 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1237 !fiq->connected || request_pending(fiq));
1238 if (err)
1239 goto err_unlock;
1240
1241 err = -ENODEV;
1242 if (!fiq->connected)
1243 goto err_unlock;
1244
1245 if (!list_empty(&fiq->interrupts)) {
1246 req = list_entry(fiq->interrupts.next, struct fuse_req,
1247 intr_entry);
1248 return fuse_read_interrupt(fiq, cs, nbytes, req);
1249 }
1250
1251 if (forget_pending(fiq)) {
1252 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1253 return fuse_read_forget(fc, fiq, cs, nbytes);
1254
1255 if (fiq->forget_batch <= -8)
1256 fiq->forget_batch = 16;
1257 }
1258
1259 req = list_entry(fiq->pending.next, struct fuse_req, list);
1260 clear_bit(FR_PENDING, &req->flags);
1261 list_del_init(&req->list);
1262 spin_unlock(&fiq->waitq.lock);
1263
1264 in = &req->in;
1265 reqsize = in->h.len;
1266 /* If request is too large, reply with an error and restart the read */
1267 if (nbytes < reqsize) {
1268 req->out.h.error = -EIO;
1269 /* SETXATTR is special, since it may contain too large data */
1270 if (in->h.opcode == FUSE_SETXATTR)
1271 req->out.h.error = -E2BIG;
1272 request_end(fc, req);
1273 goto restart;
1274 }
1275 spin_lock(&fpq->lock);
1276 list_add(&req->list, &fpq->io);
1277 spin_unlock(&fpq->lock);
1278 cs->req = req;
1279 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1280 if (!err)
1281 err = fuse_copy_args(cs, in->numargs, in->argpages,
1282 (struct fuse_arg *) in->args, 0);
1283 fuse_copy_finish(cs);
1284 spin_lock(&fpq->lock);
1285 clear_bit(FR_LOCKED, &req->flags);
1286 if (!fpq->connected) {
1287 err = -ENODEV;
1288 goto out_end;
1289 }
1290 if (err) {
1291 req->out.h.error = -EIO;
1292 goto out_end;
1293 }
1294 if (!test_bit(FR_ISREPLY, &req->flags)) {
1295 err = reqsize;
1296 goto out_end;
1297 }
1298 list_move_tail(&req->list, &fpq->processing);
1299 spin_unlock(&fpq->lock);
1300 set_bit(FR_SENT, &req->flags);
1301 /* matches barrier in request_wait_answer() */
1302 smp_mb__after_atomic();
1303 if (test_bit(FR_INTERRUPTED, &req->flags))
1304 queue_interrupt(fiq, req);
1305
1306 return reqsize;
1307
1308 out_end:
1309 if (!test_bit(FR_PRIVATE, &req->flags))
1310 list_del_init(&req->list);
1311 spin_unlock(&fpq->lock);
1312 request_end(fc, req);
1313 return err;
1314
1315 err_unlock:
1316 spin_unlock(&fiq->waitq.lock);
1317 return err;
1318 }
1319
1320 static int fuse_dev_open(struct inode *inode, struct file *file)
1321 {
1322 /*
1323 * The fuse device's file's private_data is used to hold
1324 * the fuse_conn(ection) when it is mounted, and is used to
1325 * keep track of whether the file has been mounted already.
1326 */
1327 file->private_data = NULL;
1328 return 0;
1329 }
1330
1331 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1332 {
1333 struct fuse_copy_state cs;
1334 struct file *file = iocb->ki_filp;
1335 struct fuse_dev *fud = fuse_get_dev(file);
1336
1337 if (!fud)
1338 return -EPERM;
1339
1340 if (!iter_is_iovec(to))
1341 return -EINVAL;
1342
1343 fuse_copy_init(&cs, 1, to);
1344
1345 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1346 }
1347
1348 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1349 struct pipe_inode_info *pipe,
1350 size_t len, unsigned int flags)
1351 {
1352 int total, ret;
1353 int page_nr = 0;
1354 struct pipe_buffer *bufs;
1355 struct fuse_copy_state cs;
1356 struct fuse_dev *fud = fuse_get_dev(in);
1357
1358 if (!fud)
1359 return -EPERM;
1360
1361 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1362 if (!bufs)
1363 return -ENOMEM;
1364
1365 fuse_copy_init(&cs, 1, NULL);
1366 cs.pipebufs = bufs;
1367 cs.pipe = pipe;
1368 ret = fuse_dev_do_read(fud, in, &cs, len);
1369 if (ret < 0)
1370 goto out;
1371
1372 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1373 ret = -EIO;
1374 goto out;
1375 }
1376
1377 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1378 /*
1379 * Need to be careful about this. Having buf->ops in module
1380 * code can Oops if the buffer persists after module unload.
1381 */
1382 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1383 bufs[page_nr].flags = 0;
1384 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1385 if (unlikely(ret < 0))
1386 break;
1387 }
1388 if (total)
1389 ret = total;
1390 out:
1391 for (; page_nr < cs.nr_segs; page_nr++)
1392 put_page(bufs[page_nr].page);
1393
1394 kfree(bufs);
1395 return ret;
1396 }
1397
1398 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1399 struct fuse_copy_state *cs)
1400 {
1401 struct fuse_notify_poll_wakeup_out outarg;
1402 int err = -EINVAL;
1403
1404 if (size != sizeof(outarg))
1405 goto err;
1406
1407 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1408 if (err)
1409 goto err;
1410
1411 fuse_copy_finish(cs);
1412 return fuse_notify_poll_wakeup(fc, &outarg);
1413
1414 err:
1415 fuse_copy_finish(cs);
1416 return err;
1417 }
1418
1419 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1420 struct fuse_copy_state *cs)
1421 {
1422 struct fuse_notify_inval_inode_out outarg;
1423 int err = -EINVAL;
1424
1425 if (size != sizeof(outarg))
1426 goto err;
1427
1428 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1429 if (err)
1430 goto err;
1431 fuse_copy_finish(cs);
1432
1433 down_read(&fc->killsb);
1434 err = -ENOENT;
1435 if (fc->sb) {
1436 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1437 outarg.off, outarg.len);
1438 }
1439 up_read(&fc->killsb);
1440 return err;
1441
1442 err:
1443 fuse_copy_finish(cs);
1444 return err;
1445 }
1446
1447 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1448 struct fuse_copy_state *cs)
1449 {
1450 struct fuse_notify_inval_entry_out outarg;
1451 int err = -ENOMEM;
1452 char *buf;
1453 struct qstr name;
1454
1455 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1456 if (!buf)
1457 goto err;
1458
1459 err = -EINVAL;
1460 if (size < sizeof(outarg))
1461 goto err;
1462
1463 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1464 if (err)
1465 goto err;
1466
1467 err = -ENAMETOOLONG;
1468 if (outarg.namelen > FUSE_NAME_MAX)
1469 goto err;
1470
1471 err = -EINVAL;
1472 if (size != sizeof(outarg) + outarg.namelen + 1)
1473 goto err;
1474
1475 name.name = buf;
1476 name.len = outarg.namelen;
1477 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1478 if (err)
1479 goto err;
1480 fuse_copy_finish(cs);
1481 buf[outarg.namelen] = 0;
1482
1483 down_read(&fc->killsb);
1484 err = -ENOENT;
1485 if (fc->sb)
1486 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1487 up_read(&fc->killsb);
1488 kfree(buf);
1489 return err;
1490
1491 err:
1492 kfree(buf);
1493 fuse_copy_finish(cs);
1494 return err;
1495 }
1496
1497 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1498 struct fuse_copy_state *cs)
1499 {
1500 struct fuse_notify_delete_out outarg;
1501 int err = -ENOMEM;
1502 char *buf;
1503 struct qstr name;
1504
1505 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1506 if (!buf)
1507 goto err;
1508
1509 err = -EINVAL;
1510 if (size < sizeof(outarg))
1511 goto err;
1512
1513 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1514 if (err)
1515 goto err;
1516
1517 err = -ENAMETOOLONG;
1518 if (outarg.namelen > FUSE_NAME_MAX)
1519 goto err;
1520
1521 err = -EINVAL;
1522 if (size != sizeof(outarg) + outarg.namelen + 1)
1523 goto err;
1524
1525 name.name = buf;
1526 name.len = outarg.namelen;
1527 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1528 if (err)
1529 goto err;
1530 fuse_copy_finish(cs);
1531 buf[outarg.namelen] = 0;
1532
1533 down_read(&fc->killsb);
1534 err = -ENOENT;
1535 if (fc->sb)
1536 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1537 outarg.child, &name);
1538 up_read(&fc->killsb);
1539 kfree(buf);
1540 return err;
1541
1542 err:
1543 kfree(buf);
1544 fuse_copy_finish(cs);
1545 return err;
1546 }
1547
1548 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1549 struct fuse_copy_state *cs)
1550 {
1551 struct fuse_notify_store_out outarg;
1552 struct inode *inode;
1553 struct address_space *mapping;
1554 u64 nodeid;
1555 int err;
1556 pgoff_t index;
1557 unsigned int offset;
1558 unsigned int num;
1559 loff_t file_size;
1560 loff_t end;
1561
1562 err = -EINVAL;
1563 if (size < sizeof(outarg))
1564 goto out_finish;
1565
1566 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1567 if (err)
1568 goto out_finish;
1569
1570 err = -EINVAL;
1571 if (size - sizeof(outarg) != outarg.size)
1572 goto out_finish;
1573
1574 nodeid = outarg.nodeid;
1575
1576 down_read(&fc->killsb);
1577
1578 err = -ENOENT;
1579 if (!fc->sb)
1580 goto out_up_killsb;
1581
1582 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1583 if (!inode)
1584 goto out_up_killsb;
1585
1586 mapping = inode->i_mapping;
1587 index = outarg.offset >> PAGE_SHIFT;
1588 offset = outarg.offset & ~PAGE_MASK;
1589 file_size = i_size_read(inode);
1590 end = outarg.offset + outarg.size;
1591 if (end > file_size) {
1592 file_size = end;
1593 fuse_write_update_size(inode, file_size);
1594 }
1595
1596 num = outarg.size;
1597 while (num) {
1598 struct page *page;
1599 unsigned int this_num;
1600
1601 err = -ENOMEM;
1602 page = find_or_create_page(mapping, index,
1603 mapping_gfp_mask(mapping));
1604 if (!page)
1605 goto out_iput;
1606
1607 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1608 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1609 if (!err && offset == 0 &&
1610 (this_num == PAGE_SIZE || file_size == end))
1611 SetPageUptodate(page);
1612 unlock_page(page);
1613 put_page(page);
1614
1615 if (err)
1616 goto out_iput;
1617
1618 num -= this_num;
1619 offset = 0;
1620 index++;
1621 }
1622
1623 err = 0;
1624
1625 out_iput:
1626 iput(inode);
1627 out_up_killsb:
1628 up_read(&fc->killsb);
1629 out_finish:
1630 fuse_copy_finish(cs);
1631 return err;
1632 }
1633
1634 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1635 {
1636 release_pages(req->pages, req->num_pages, false);
1637 }
1638
1639 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1640 struct fuse_notify_retrieve_out *outarg)
1641 {
1642 int err;
1643 struct address_space *mapping = inode->i_mapping;
1644 struct fuse_req *req;
1645 pgoff_t index;
1646 loff_t file_size;
1647 unsigned int num;
1648 unsigned int offset;
1649 size_t total_len = 0;
1650 int num_pages;
1651
1652 offset = outarg->offset & ~PAGE_MASK;
1653 file_size = i_size_read(inode);
1654
1655 num = outarg->size;
1656 if (outarg->offset > file_size)
1657 num = 0;
1658 else if (outarg->offset + num > file_size)
1659 num = file_size - outarg->offset;
1660
1661 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1662 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1663
1664 req = fuse_get_req(fc, num_pages);
1665 if (IS_ERR(req))
1666 return PTR_ERR(req);
1667
1668 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1669 req->in.h.nodeid = outarg->nodeid;
1670 req->in.numargs = 2;
1671 req->in.argpages = 1;
1672 req->page_descs[0].offset = offset;
1673 req->end = fuse_retrieve_end;
1674
1675 index = outarg->offset >> PAGE_SHIFT;
1676
1677 while (num && req->num_pages < num_pages) {
1678 struct page *page;
1679 unsigned int this_num;
1680
1681 page = find_get_page(mapping, index);
1682 if (!page)
1683 break;
1684
1685 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1686 req->pages[req->num_pages] = page;
1687 req->page_descs[req->num_pages].length = this_num;
1688 req->num_pages++;
1689
1690 offset = 0;
1691 num -= this_num;
1692 total_len += this_num;
1693 index++;
1694 }
1695 req->misc.retrieve_in.offset = outarg->offset;
1696 req->misc.retrieve_in.size = total_len;
1697 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1698 req->in.args[0].value = &req->misc.retrieve_in;
1699 req->in.args[1].size = total_len;
1700
1701 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1702 if (err)
1703 fuse_retrieve_end(fc, req);
1704
1705 return err;
1706 }
1707
1708 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1709 struct fuse_copy_state *cs)
1710 {
1711 struct fuse_notify_retrieve_out outarg;
1712 struct inode *inode;
1713 int err;
1714
1715 err = -EINVAL;
1716 if (size != sizeof(outarg))
1717 goto copy_finish;
1718
1719 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1720 if (err)
1721 goto copy_finish;
1722
1723 fuse_copy_finish(cs);
1724
1725 down_read(&fc->killsb);
1726 err = -ENOENT;
1727 if (fc->sb) {
1728 u64 nodeid = outarg.nodeid;
1729
1730 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1731 if (inode) {
1732 err = fuse_retrieve(fc, inode, &outarg);
1733 iput(inode);
1734 }
1735 }
1736 up_read(&fc->killsb);
1737
1738 return err;
1739
1740 copy_finish:
1741 fuse_copy_finish(cs);
1742 return err;
1743 }
1744
1745 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1746 unsigned int size, struct fuse_copy_state *cs)
1747 {
1748 /* Don't try to move pages (yet) */
1749 cs->move_pages = 0;
1750
1751 switch (code) {
1752 case FUSE_NOTIFY_POLL:
1753 return fuse_notify_poll(fc, size, cs);
1754
1755 case FUSE_NOTIFY_INVAL_INODE:
1756 return fuse_notify_inval_inode(fc, size, cs);
1757
1758 case FUSE_NOTIFY_INVAL_ENTRY:
1759 return fuse_notify_inval_entry(fc, size, cs);
1760
1761 case FUSE_NOTIFY_STORE:
1762 return fuse_notify_store(fc, size, cs);
1763
1764 case FUSE_NOTIFY_RETRIEVE:
1765 return fuse_notify_retrieve(fc, size, cs);
1766
1767 case FUSE_NOTIFY_DELETE:
1768 return fuse_notify_delete(fc, size, cs);
1769
1770 default:
1771 fuse_copy_finish(cs);
1772 return -EINVAL;
1773 }
1774 }
1775
1776 /* Look up request on processing list by unique ID */
1777 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1778 {
1779 struct fuse_req *req;
1780
1781 list_for_each_entry(req, &fpq->processing, list) {
1782 if (req->in.h.unique == unique || req->intr_unique == unique)
1783 return req;
1784 }
1785 return NULL;
1786 }
1787
1788 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1789 unsigned nbytes)
1790 {
1791 unsigned reqsize = sizeof(struct fuse_out_header);
1792
1793 if (out->h.error)
1794 return nbytes != reqsize ? -EINVAL : 0;
1795
1796 reqsize += len_args(out->numargs, out->args);
1797
1798 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1799 return -EINVAL;
1800 else if (reqsize > nbytes) {
1801 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1802 unsigned diffsize = reqsize - nbytes;
1803 if (diffsize > lastarg->size)
1804 return -EINVAL;
1805 lastarg->size -= diffsize;
1806 }
1807 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1808 out->page_zeroing);
1809 }
1810
1811 /*
1812 * Write a single reply to a request. First the header is copied from
1813 * the write buffer. The request is then searched on the processing
1814 * list by the unique ID found in the header. If found, then remove
1815 * it from the list and copy the rest of the buffer to the request.
1816 * The request is finished by calling request_end()
1817 */
1818 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1819 struct fuse_copy_state *cs, size_t nbytes)
1820 {
1821 int err;
1822 struct fuse_conn *fc = fud->fc;
1823 struct fuse_pqueue *fpq = &fud->pq;
1824 struct fuse_req *req;
1825 struct fuse_out_header oh;
1826
1827 if (task_active_pid_ns(current) != fc->pid_ns)
1828 return -EIO;
1829
1830 if (nbytes < sizeof(struct fuse_out_header))
1831 return -EINVAL;
1832
1833 err = fuse_copy_one(cs, &oh, sizeof(oh));
1834 if (err)
1835 goto err_finish;
1836
1837 err = -EINVAL;
1838 if (oh.len != nbytes)
1839 goto err_finish;
1840
1841 /*
1842 * Zero oh.unique indicates unsolicited notification message
1843 * and error contains notification code.
1844 */
1845 if (!oh.unique) {
1846 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1847 return err ? err : nbytes;
1848 }
1849
1850 err = -EINVAL;
1851 if (oh.error <= -1000 || oh.error > 0)
1852 goto err_finish;
1853
1854 spin_lock(&fpq->lock);
1855 err = -ENOENT;
1856 if (!fpq->connected)
1857 goto err_unlock_pq;
1858
1859 req = request_find(fpq, oh.unique);
1860 if (!req)
1861 goto err_unlock_pq;
1862
1863 /* Is it an interrupt reply? */
1864 if (req->intr_unique == oh.unique) {
1865 spin_unlock(&fpq->lock);
1866
1867 err = -EINVAL;
1868 if (nbytes != sizeof(struct fuse_out_header))
1869 goto err_finish;
1870
1871 if (oh.error == -ENOSYS)
1872 fc->no_interrupt = 1;
1873 else if (oh.error == -EAGAIN)
1874 queue_interrupt(&fc->iq, req);
1875
1876 fuse_copy_finish(cs);
1877 return nbytes;
1878 }
1879
1880 clear_bit(FR_SENT, &req->flags);
1881 list_move(&req->list, &fpq->io);
1882 req->out.h = oh;
1883 set_bit(FR_LOCKED, &req->flags);
1884 spin_unlock(&fpq->lock);
1885 cs->req = req;
1886 if (!req->out.page_replace)
1887 cs->move_pages = 0;
1888
1889 err = copy_out_args(cs, &req->out, nbytes);
1890 fuse_copy_finish(cs);
1891
1892 spin_lock(&fpq->lock);
1893 clear_bit(FR_LOCKED, &req->flags);
1894 if (!fpq->connected)
1895 err = -ENOENT;
1896 else if (err)
1897 req->out.h.error = -EIO;
1898 if (!test_bit(FR_PRIVATE, &req->flags))
1899 list_del_init(&req->list);
1900 spin_unlock(&fpq->lock);
1901
1902 request_end(fc, req);
1903
1904 return err ? err : nbytes;
1905
1906 err_unlock_pq:
1907 spin_unlock(&fpq->lock);
1908 err_finish:
1909 fuse_copy_finish(cs);
1910 return err;
1911 }
1912
1913 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1914 {
1915 struct fuse_copy_state cs;
1916 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1917
1918 if (!fud)
1919 return -EPERM;
1920
1921 if (!iter_is_iovec(from))
1922 return -EINVAL;
1923
1924 fuse_copy_init(&cs, 0, from);
1925
1926 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1927 }
1928
1929 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1930 struct file *out, loff_t *ppos,
1931 size_t len, unsigned int flags)
1932 {
1933 unsigned nbuf;
1934 unsigned idx;
1935 struct pipe_buffer *bufs;
1936 struct fuse_copy_state cs;
1937 struct fuse_dev *fud;
1938 size_t rem;
1939 ssize_t ret;
1940
1941 fud = fuse_get_dev(out);
1942 if (!fud)
1943 return -EPERM;
1944
1945 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1946 if (!bufs)
1947 return -ENOMEM;
1948
1949 pipe_lock(pipe);
1950 nbuf = 0;
1951 rem = 0;
1952 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1953 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1954
1955 ret = -EINVAL;
1956 if (rem < len) {
1957 pipe_unlock(pipe);
1958 goto out;
1959 }
1960
1961 rem = len;
1962 while (rem) {
1963 struct pipe_buffer *ibuf;
1964 struct pipe_buffer *obuf;
1965
1966 BUG_ON(nbuf >= pipe->buffers);
1967 BUG_ON(!pipe->nrbufs);
1968 ibuf = &pipe->bufs[pipe->curbuf];
1969 obuf = &bufs[nbuf];
1970
1971 if (rem >= ibuf->len) {
1972 *obuf = *ibuf;
1973 ibuf->ops = NULL;
1974 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1975 pipe->nrbufs--;
1976 } else {
1977 pipe_buf_get(pipe, ibuf);
1978 *obuf = *ibuf;
1979 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1980 obuf->len = rem;
1981 ibuf->offset += obuf->len;
1982 ibuf->len -= obuf->len;
1983 }
1984 nbuf++;
1985 rem -= obuf->len;
1986 }
1987 pipe_unlock(pipe);
1988
1989 fuse_copy_init(&cs, 0, NULL);
1990 cs.pipebufs = bufs;
1991 cs.nr_segs = nbuf;
1992 cs.pipe = pipe;
1993
1994 if (flags & SPLICE_F_MOVE)
1995 cs.move_pages = 1;
1996
1997 ret = fuse_dev_do_write(fud, &cs, len);
1998
1999 for (idx = 0; idx < nbuf; idx++)
2000 pipe_buf_release(pipe, &bufs[idx]);
2001
2002 out:
2003 kfree(bufs);
2004 return ret;
2005 }
2006
2007 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2008 {
2009 unsigned mask = POLLOUT | POLLWRNORM;
2010 struct fuse_iqueue *fiq;
2011 struct fuse_dev *fud = fuse_get_dev(file);
2012
2013 if (!fud)
2014 return POLLERR;
2015
2016 fiq = &fud->fc->iq;
2017 poll_wait(file, &fiq->waitq, wait);
2018
2019 spin_lock(&fiq->waitq.lock);
2020 if (!fiq->connected)
2021 mask = POLLERR;
2022 else if (request_pending(fiq))
2023 mask |= POLLIN | POLLRDNORM;
2024 spin_unlock(&fiq->waitq.lock);
2025
2026 return mask;
2027 }
2028
2029 /*
2030 * Abort all requests on the given list (pending or processing)
2031 *
2032 * This function releases and reacquires fc->lock
2033 */
2034 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2035 {
2036 while (!list_empty(head)) {
2037 struct fuse_req *req;
2038 req = list_entry(head->next, struct fuse_req, list);
2039 req->out.h.error = -ECONNABORTED;
2040 clear_bit(FR_SENT, &req->flags);
2041 list_del_init(&req->list);
2042 request_end(fc, req);
2043 }
2044 }
2045
2046 static void end_polls(struct fuse_conn *fc)
2047 {
2048 struct rb_node *p;
2049
2050 p = rb_first(&fc->polled_files);
2051
2052 while (p) {
2053 struct fuse_file *ff;
2054 ff = rb_entry(p, struct fuse_file, polled_node);
2055 wake_up_interruptible_all(&ff->poll_wait);
2056
2057 p = rb_next(p);
2058 }
2059 }
2060
2061 /*
2062 * Abort all requests.
2063 *
2064 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2065 * filesystem.
2066 *
2067 * The same effect is usually achievable through killing the filesystem daemon
2068 * and all users of the filesystem. The exception is the combination of an
2069 * asynchronous request and the tricky deadlock (see
2070 * Documentation/filesystems/fuse.txt).
2071 *
2072 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2073 * requests, they should be finished off immediately. Locked requests will be
2074 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2075 * requests. It is possible that some request will finish before we can. This
2076 * is OK, the request will in that case be removed from the list before we touch
2077 * it.
2078 */
2079 void fuse_abort_conn(struct fuse_conn *fc)
2080 {
2081 struct fuse_iqueue *fiq = &fc->iq;
2082
2083 spin_lock(&fc->lock);
2084 if (fc->connected) {
2085 struct fuse_dev *fud;
2086 struct fuse_req *req, *next;
2087 LIST_HEAD(to_end1);
2088 LIST_HEAD(to_end2);
2089
2090 fc->connected = 0;
2091 fc->blocked = 0;
2092 fuse_set_initialized(fc);
2093 list_for_each_entry(fud, &fc->devices, entry) {
2094 struct fuse_pqueue *fpq = &fud->pq;
2095
2096 spin_lock(&fpq->lock);
2097 fpq->connected = 0;
2098 list_for_each_entry_safe(req, next, &fpq->io, list) {
2099 req->out.h.error = -ECONNABORTED;
2100 spin_lock(&req->waitq.lock);
2101 set_bit(FR_ABORTED, &req->flags);
2102 if (!test_bit(FR_LOCKED, &req->flags)) {
2103 set_bit(FR_PRIVATE, &req->flags);
2104 list_move(&req->list, &to_end1);
2105 }
2106 spin_unlock(&req->waitq.lock);
2107 }
2108 list_splice_init(&fpq->processing, &to_end2);
2109 spin_unlock(&fpq->lock);
2110 }
2111 fc->max_background = UINT_MAX;
2112 flush_bg_queue(fc);
2113
2114 spin_lock(&fiq->waitq.lock);
2115 fiq->connected = 0;
2116 list_splice_init(&fiq->pending, &to_end2);
2117 list_for_each_entry(req, &to_end2, list)
2118 clear_bit(FR_PENDING, &req->flags);
2119 while (forget_pending(fiq))
2120 kfree(dequeue_forget(fiq, 1, NULL));
2121 wake_up_all_locked(&fiq->waitq);
2122 spin_unlock(&fiq->waitq.lock);
2123 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2124 end_polls(fc);
2125 wake_up_all(&fc->blocked_waitq);
2126 spin_unlock(&fc->lock);
2127
2128 while (!list_empty(&to_end1)) {
2129 req = list_first_entry(&to_end1, struct fuse_req, list);
2130 __fuse_get_request(req);
2131 list_del_init(&req->list);
2132 request_end(fc, req);
2133 }
2134 end_requests(fc, &to_end2);
2135 } else {
2136 spin_unlock(&fc->lock);
2137 }
2138 }
2139 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2140
2141 int fuse_dev_release(struct inode *inode, struct file *file)
2142 {
2143 struct fuse_dev *fud = fuse_get_dev(file);
2144
2145 if (fud) {
2146 struct fuse_conn *fc = fud->fc;
2147 struct fuse_pqueue *fpq = &fud->pq;
2148
2149 WARN_ON(!list_empty(&fpq->io));
2150 end_requests(fc, &fpq->processing);
2151 /* Are we the last open device? */
2152 if (atomic_dec_and_test(&fc->dev_count)) {
2153 WARN_ON(fc->iq.fasync != NULL);
2154 fuse_abort_conn(fc);
2155 }
2156 fuse_dev_free(fud);
2157 }
2158 return 0;
2159 }
2160 EXPORT_SYMBOL_GPL(fuse_dev_release);
2161
2162 static int fuse_dev_fasync(int fd, struct file *file, int on)
2163 {
2164 struct fuse_dev *fud = fuse_get_dev(file);
2165
2166 if (!fud)
2167 return -EPERM;
2168
2169 /* No locking - fasync_helper does its own locking */
2170 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2171 }
2172
2173 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2174 {
2175 struct fuse_dev *fud;
2176
2177 if (new->private_data)
2178 return -EINVAL;
2179
2180 fud = fuse_dev_alloc(fc);
2181 if (!fud)
2182 return -ENOMEM;
2183
2184 new->private_data = fud;
2185 atomic_inc(&fc->dev_count);
2186
2187 return 0;
2188 }
2189
2190 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2191 unsigned long arg)
2192 {
2193 int err = -ENOTTY;
2194
2195 if (cmd == FUSE_DEV_IOC_CLONE) {
2196 int oldfd;
2197
2198 err = -EFAULT;
2199 if (!get_user(oldfd, (__u32 __user *) arg)) {
2200 struct file *old = fget(oldfd);
2201
2202 err = -EINVAL;
2203 if (old) {
2204 struct fuse_dev *fud = NULL;
2205
2206 /*
2207 * Check against file->f_op because CUSE
2208 * uses the same ioctl handler.
2209 */
2210 if (old->f_op == file->f_op &&
2211 old->f_cred->user_ns == file->f_cred->user_ns)
2212 fud = fuse_get_dev(old);
2213
2214 if (fud) {
2215 mutex_lock(&fuse_mutex);
2216 err = fuse_device_clone(fud->fc, file);
2217 mutex_unlock(&fuse_mutex);
2218 }
2219 fput(old);
2220 }
2221 }
2222 }
2223 return err;
2224 }
2225
2226 const struct file_operations fuse_dev_operations = {
2227 .owner = THIS_MODULE,
2228 .open = fuse_dev_open,
2229 .llseek = no_llseek,
2230 .read_iter = fuse_dev_read,
2231 .splice_read = fuse_dev_splice_read,
2232 .write_iter = fuse_dev_write,
2233 .splice_write = fuse_dev_splice_write,
2234 .poll = fuse_dev_poll,
2235 .release = fuse_dev_release,
2236 .fasync = fuse_dev_fasync,
2237 .unlocked_ioctl = fuse_dev_ioctl,
2238 .compat_ioctl = fuse_dev_ioctl,
2239 };
2240 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2241
2242 static struct miscdevice fuse_miscdevice = {
2243 .minor = FUSE_MINOR,
2244 .name = "fuse",
2245 .fops = &fuse_dev_operations,
2246 };
2247
2248 int __init fuse_dev_init(void)
2249 {
2250 int err = -ENOMEM;
2251 fuse_req_cachep = kmem_cache_create("fuse_request",
2252 sizeof(struct fuse_req),
2253 0, 0, NULL);
2254 if (!fuse_req_cachep)
2255 goto out;
2256
2257 err = misc_register(&fuse_miscdevice);
2258 if (err)
2259 goto out_cache_clean;
2260
2261 return 0;
2262
2263 out_cache_clean:
2264 kmem_cache_destroy(fuse_req_cachep);
2265 out:
2266 return err;
2267 }
2268
2269 void fuse_dev_cleanup(void)
2270 {
2271 misc_deregister(&fuse_miscdevice);
2272 kmem_cache_destroy(fuse_req_cachep);
2273 }
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