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[mirror_ubuntu-bionic-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 #include <linux/sched.h>
24
25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26 MODULE_ALIAS("devname:fuse");
27
28 static struct kmem_cache *fuse_req_cachep;
29
30 static struct fuse_dev *fuse_get_dev(struct file *file)
31 {
32 /*
33 * Lockless access is OK, because file->private data is set
34 * once during mount and is valid until the file is released.
35 */
36 return READ_ONCE(file->private_data);
37 }
38
39 static void fuse_request_init(struct fuse_req *req, struct page **pages,
40 struct fuse_page_desc *page_descs,
41 unsigned npages)
42 {
43 memset(req, 0, sizeof(*req));
44 memset(pages, 0, sizeof(*pages) * npages);
45 memset(page_descs, 0, sizeof(*page_descs) * npages);
46 INIT_LIST_HEAD(&req->list);
47 INIT_LIST_HEAD(&req->intr_entry);
48 init_waitqueue_head(&req->waitq);
49 refcount_set(&req->count, 1);
50 req->pages = pages;
51 req->page_descs = page_descs;
52 req->max_pages = npages;
53 __set_bit(FR_PENDING, &req->flags);
54 }
55
56 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
57 {
58 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
59 if (req) {
60 struct page **pages;
61 struct fuse_page_desc *page_descs;
62
63 if (npages <= FUSE_REQ_INLINE_PAGES) {
64 pages = req->inline_pages;
65 page_descs = req->inline_page_descs;
66 } else {
67 pages = kmalloc(sizeof(struct page *) * npages, flags);
68 page_descs = kmalloc(sizeof(struct fuse_page_desc) *
69 npages, flags);
70 }
71
72 if (!pages || !page_descs) {
73 kfree(pages);
74 kfree(page_descs);
75 kmem_cache_free(fuse_req_cachep, req);
76 return NULL;
77 }
78
79 fuse_request_init(req, pages, page_descs, npages);
80 }
81 return req;
82 }
83
84 struct fuse_req *fuse_request_alloc(unsigned npages)
85 {
86 return __fuse_request_alloc(npages, GFP_KERNEL);
87 }
88 EXPORT_SYMBOL_GPL(fuse_request_alloc);
89
90 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
91 {
92 return __fuse_request_alloc(npages, GFP_NOFS);
93 }
94
95 void fuse_request_free(struct fuse_req *req)
96 {
97 if (req->pages != req->inline_pages) {
98 kfree(req->pages);
99 kfree(req->page_descs);
100 }
101 kmem_cache_free(fuse_req_cachep, req);
102 }
103
104 void __fuse_get_request(struct fuse_req *req)
105 {
106 refcount_inc(&req->count);
107 }
108
109 /* Must be called with > 1 refcount */
110 static void __fuse_put_request(struct fuse_req *req)
111 {
112 refcount_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(fc->user_ns, current_fsuid());
118 req->in.h.gid = from_kgid(fc->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 void fuse_drop_waiting(struct fuse_conn *fc)
135 {
136 if (fc->connected) {
137 atomic_dec(&fc->num_waiting);
138 } else if (atomic_dec_and_test(&fc->num_waiting)) {
139 /* wake up aborters */
140 wake_up_all(&fc->blocked_waitq);
141 }
142 }
143
144 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
145 bool for_background)
146 {
147 struct fuse_req *req;
148 int err;
149 atomic_inc(&fc->num_waiting);
150
151 if (fuse_block_alloc(fc, for_background)) {
152 err = -EINTR;
153 if (wait_event_killable_exclusive(fc->blocked_waitq,
154 !fuse_block_alloc(fc, for_background)))
155 goto out;
156 }
157 /* Matches smp_wmb() in fuse_set_initialized() */
158 smp_rmb();
159
160 err = -ENOTCONN;
161 if (!fc->connected)
162 goto out;
163
164 err = -ECONNREFUSED;
165 if (fc->conn_error)
166 goto out;
167
168 req = fuse_request_alloc(npages);
169 err = -ENOMEM;
170 if (!req) {
171 if (for_background)
172 wake_up(&fc->blocked_waitq);
173 goto out;
174 }
175
176 fuse_req_init_context(fc, req);
177 __set_bit(FR_WAITING, &req->flags);
178 if (for_background)
179 __set_bit(FR_BACKGROUND, &req->flags);
180 if (req->in.h.uid == (uid_t)-1 || req->in.h.gid == (gid_t)-1) {
181 fuse_put_request(fc, req);
182 return ERR_PTR(-EOVERFLOW);
183 }
184
185 return req;
186
187 out:
188 fuse_drop_waiting(fc);
189 return ERR_PTR(err);
190 }
191
192 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
193 {
194 return __fuse_get_req(fc, npages, false);
195 }
196 EXPORT_SYMBOL_GPL(fuse_get_req);
197
198 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
199 unsigned npages)
200 {
201 return __fuse_get_req(fc, npages, true);
202 }
203 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
204
205 /*
206 * Return request in fuse_file->reserved_req. However that may
207 * currently be in use. If that is the case, wait for it to become
208 * available.
209 */
210 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
211 struct file *file)
212 {
213 struct fuse_req *req = NULL;
214 struct fuse_file *ff = file->private_data;
215
216 do {
217 wait_event(fc->reserved_req_waitq, ff->reserved_req);
218 spin_lock(&fc->lock);
219 if (ff->reserved_req) {
220 req = ff->reserved_req;
221 ff->reserved_req = NULL;
222 req->stolen_file = get_file(file);
223 }
224 spin_unlock(&fc->lock);
225 } while (!req);
226
227 return req;
228 }
229
230 /*
231 * Put stolen request back into fuse_file->reserved_req
232 */
233 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
234 {
235 struct file *file = req->stolen_file;
236 struct fuse_file *ff = file->private_data;
237
238 spin_lock(&fc->lock);
239 fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
240 BUG_ON(ff->reserved_req);
241 ff->reserved_req = req;
242 wake_up_all(&fc->reserved_req_waitq);
243 spin_unlock(&fc->lock);
244 fput(file);
245 }
246
247 /*
248 * Gets a requests for a file operation, always succeeds
249 *
250 * This is used for sending the FLUSH request, which must get to
251 * userspace, due to POSIX locks which may need to be unlocked.
252 *
253 * If allocation fails due to OOM, use the reserved request in
254 * fuse_file.
255 *
256 * This is very unlikely to deadlock accidentally, since the
257 * filesystem should not have it's own file open. If deadlock is
258 * intentional, it can still be broken by "aborting" the filesystem.
259 */
260 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
261 struct file *file)
262 {
263 struct fuse_req *req;
264
265 atomic_inc(&fc->num_waiting);
266 wait_event(fc->blocked_waitq, fc->initialized);
267 /* Matches smp_wmb() in fuse_set_initialized() */
268 smp_rmb();
269 req = fuse_request_alloc(0);
270 if (!req)
271 req = get_reserved_req(fc, file);
272
273 fuse_req_init_context(fc, req);
274 __set_bit(FR_WAITING, &req->flags);
275 __clear_bit(FR_BACKGROUND, &req->flags);
276 return req;
277 }
278
279 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
280 {
281 if (refcount_dec_and_test(&req->count)) {
282 if (test_bit(FR_BACKGROUND, &req->flags)) {
283 /*
284 * We get here in the unlikely case that a background
285 * request was allocated but not sent
286 */
287 spin_lock(&fc->lock);
288 if (!fc->blocked)
289 wake_up(&fc->blocked_waitq);
290 spin_unlock(&fc->lock);
291 }
292
293 if (test_bit(FR_WAITING, &req->flags)) {
294 __clear_bit(FR_WAITING, &req->flags);
295 fuse_drop_waiting(fc);
296 }
297
298 if (req->stolen_file)
299 put_reserved_req(fc, req);
300 else
301 fuse_request_free(req);
302 }
303 }
304 EXPORT_SYMBOL_GPL(fuse_put_request);
305
306 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
307 {
308 unsigned nbytes = 0;
309 unsigned i;
310
311 for (i = 0; i < numargs; i++)
312 nbytes += args[i].size;
313
314 return nbytes;
315 }
316
317 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
318 {
319 return ++fiq->reqctr;
320 }
321
322 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
323 {
324 req->in.h.len = sizeof(struct fuse_in_header) +
325 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
326 list_add_tail(&req->list, &fiq->pending);
327 wake_up_locked(&fiq->waitq);
328 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
329 }
330
331 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
332 u64 nodeid, u64 nlookup)
333 {
334 struct fuse_iqueue *fiq = &fc->iq;
335
336 forget->forget_one.nodeid = nodeid;
337 forget->forget_one.nlookup = nlookup;
338
339 spin_lock(&fiq->waitq.lock);
340 if (fiq->connected) {
341 fiq->forget_list_tail->next = forget;
342 fiq->forget_list_tail = forget;
343 wake_up_locked(&fiq->waitq);
344 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
345 } else {
346 kfree(forget);
347 }
348 spin_unlock(&fiq->waitq.lock);
349 }
350
351 static void flush_bg_queue(struct fuse_conn *fc)
352 {
353 while (fc->active_background < fc->max_background &&
354 !list_empty(&fc->bg_queue)) {
355 struct fuse_req *req;
356 struct fuse_iqueue *fiq = &fc->iq;
357
358 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
359 list_del(&req->list);
360 fc->active_background++;
361 spin_lock(&fiq->waitq.lock);
362 req->in.h.unique = fuse_get_unique(fiq);
363 queue_request(fiq, req);
364 spin_unlock(&fiq->waitq.lock);
365 }
366 }
367
368 /*
369 * This function is called when a request is finished. Either a reply
370 * has arrived or it was aborted (and not yet sent) or some error
371 * occurred during communication with userspace, or the device file
372 * was closed. The requester thread is woken up (if still waiting),
373 * the 'end' callback is called if given, else the reference to the
374 * request is released
375 */
376 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
377 {
378 struct fuse_iqueue *fiq = &fc->iq;
379
380 if (test_and_set_bit(FR_FINISHED, &req->flags))
381 goto put_request;
382
383 spin_lock(&fiq->waitq.lock);
384 list_del_init(&req->intr_entry);
385 spin_unlock(&fiq->waitq.lock);
386 WARN_ON(test_bit(FR_PENDING, &req->flags));
387 WARN_ON(test_bit(FR_SENT, &req->flags));
388 if (test_bit(FR_BACKGROUND, &req->flags)) {
389 spin_lock(&fc->lock);
390 clear_bit(FR_BACKGROUND, &req->flags);
391 if (fc->num_background == fc->max_background)
392 fc->blocked = 0;
393
394 /* Wake up next waiter, if any */
395 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
396 wake_up(&fc->blocked_waitq);
397
398 if (fc->num_background == fc->congestion_threshold && fc->sb) {
399 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
400 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
401 }
402 fc->num_background--;
403 fc->active_background--;
404 flush_bg_queue(fc);
405 spin_unlock(&fc->lock);
406 }
407 wake_up(&req->waitq);
408 if (req->end)
409 req->end(fc, req);
410 put_request:
411 fuse_put_request(fc, req);
412 }
413
414 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
415 {
416 spin_lock(&fiq->waitq.lock);
417 if (test_bit(FR_FINISHED, &req->flags)) {
418 spin_unlock(&fiq->waitq.lock);
419 return;
420 }
421 if (list_empty(&req->intr_entry)) {
422 list_add_tail(&req->intr_entry, &fiq->interrupts);
423 wake_up_locked(&fiq->waitq);
424 }
425 spin_unlock(&fiq->waitq.lock);
426 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
427 }
428
429 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
430 {
431 struct fuse_iqueue *fiq = &fc->iq;
432 int err;
433
434 if (!fc->no_interrupt) {
435 /* Any signal may interrupt this */
436 err = wait_event_interruptible(req->waitq,
437 test_bit(FR_FINISHED, &req->flags));
438 if (!err)
439 return;
440
441 set_bit(FR_INTERRUPTED, &req->flags);
442 /* matches barrier in fuse_dev_do_read() */
443 smp_mb__after_atomic();
444 if (test_bit(FR_SENT, &req->flags))
445 queue_interrupt(fiq, req);
446 }
447
448 if (!test_bit(FR_FORCE, &req->flags)) {
449 /* Only fatal signals may interrupt this */
450 err = wait_event_killable(req->waitq,
451 test_bit(FR_FINISHED, &req->flags));
452 if (!err)
453 return;
454
455 spin_lock(&fiq->waitq.lock);
456 /* Request is not yet in userspace, bail out */
457 if (test_bit(FR_PENDING, &req->flags)) {
458 list_del(&req->list);
459 spin_unlock(&fiq->waitq.lock);
460 __fuse_put_request(req);
461 req->out.h.error = -EINTR;
462 return;
463 }
464 spin_unlock(&fiq->waitq.lock);
465 }
466
467 /*
468 * Either request is already in userspace, or it was forced.
469 * Wait it out.
470 */
471 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
472 }
473
474 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
475 {
476 struct fuse_iqueue *fiq = &fc->iq;
477
478 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
479 spin_lock(&fiq->waitq.lock);
480 if (!fiq->connected) {
481 spin_unlock(&fiq->waitq.lock);
482 req->out.h.error = -ENOTCONN;
483 } else {
484 req->in.h.unique = fuse_get_unique(fiq);
485 queue_request(fiq, req);
486 /* acquire extra reference, since request is still needed
487 after request_end() */
488 __fuse_get_request(req);
489 spin_unlock(&fiq->waitq.lock);
490
491 request_wait_answer(fc, req);
492 /* Pairs with smp_wmb() in request_end() */
493 smp_rmb();
494 }
495 }
496
497 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
498 {
499 __set_bit(FR_ISREPLY, &req->flags);
500 if (!test_bit(FR_WAITING, &req->flags)) {
501 __set_bit(FR_WAITING, &req->flags);
502 atomic_inc(&fc->num_waiting);
503 }
504 __fuse_request_send(fc, req);
505 }
506 EXPORT_SYMBOL_GPL(fuse_request_send);
507
508 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
509 {
510 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
511 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
512
513 if (fc->minor < 9) {
514 switch (args->in.h.opcode) {
515 case FUSE_LOOKUP:
516 case FUSE_CREATE:
517 case FUSE_MKNOD:
518 case FUSE_MKDIR:
519 case FUSE_SYMLINK:
520 case FUSE_LINK:
521 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
522 break;
523 case FUSE_GETATTR:
524 case FUSE_SETATTR:
525 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
526 break;
527 }
528 }
529 if (fc->minor < 12) {
530 switch (args->in.h.opcode) {
531 case FUSE_CREATE:
532 args->in.args[0].size = sizeof(struct fuse_open_in);
533 break;
534 case FUSE_MKNOD:
535 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
536 break;
537 }
538 }
539 }
540
541 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
542 {
543 struct fuse_req *req;
544 ssize_t ret;
545
546 req = fuse_get_req(fc, 0);
547 if (IS_ERR(req))
548 return PTR_ERR(req);
549
550 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
551 fuse_adjust_compat(fc, args);
552
553 req->in.h.opcode = args->in.h.opcode;
554 req->in.h.nodeid = args->in.h.nodeid;
555 req->in.numargs = args->in.numargs;
556 memcpy(req->in.args, args->in.args,
557 args->in.numargs * sizeof(struct fuse_in_arg));
558 req->out.argvar = args->out.argvar;
559 req->out.numargs = args->out.numargs;
560 memcpy(req->out.args, args->out.args,
561 args->out.numargs * sizeof(struct fuse_arg));
562 fuse_request_send(fc, req);
563 ret = req->out.h.error;
564 if (!ret && args->out.argvar) {
565 BUG_ON(args->out.numargs != 1);
566 ret = req->out.args[0].size;
567 }
568 fuse_put_request(fc, req);
569
570 return ret;
571 }
572
573 /*
574 * Called under fc->lock
575 *
576 * fc->connected must have been checked previously
577 */
578 void fuse_request_send_background_locked(struct fuse_conn *fc,
579 struct fuse_req *req)
580 {
581 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
582 if (!test_bit(FR_WAITING, &req->flags)) {
583 __set_bit(FR_WAITING, &req->flags);
584 atomic_inc(&fc->num_waiting);
585 }
586 __set_bit(FR_ISREPLY, &req->flags);
587 fc->num_background++;
588 if (fc->num_background == fc->max_background)
589 fc->blocked = 1;
590 if (fc->num_background == fc->congestion_threshold && fc->sb) {
591 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
592 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
593 }
594 list_add_tail(&req->list, &fc->bg_queue);
595 flush_bg_queue(fc);
596 }
597
598 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
599 {
600 BUG_ON(!req->end);
601 spin_lock(&fc->lock);
602 if (fc->connected) {
603 fuse_request_send_background_locked(fc, req);
604 spin_unlock(&fc->lock);
605 } else {
606 spin_unlock(&fc->lock);
607 req->out.h.error = -ENOTCONN;
608 req->end(fc, req);
609 fuse_put_request(fc, req);
610 }
611 }
612 EXPORT_SYMBOL_GPL(fuse_request_send_background);
613
614 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
615 struct fuse_req *req, u64 unique)
616 {
617 int err = -ENODEV;
618 struct fuse_iqueue *fiq = &fc->iq;
619
620 __clear_bit(FR_ISREPLY, &req->flags);
621 req->in.h.unique = unique;
622 spin_lock(&fiq->waitq.lock);
623 if (fiq->connected) {
624 queue_request(fiq, req);
625 err = 0;
626 }
627 spin_unlock(&fiq->waitq.lock);
628
629 return err;
630 }
631
632 void fuse_force_forget(struct file *file, u64 nodeid)
633 {
634 struct inode *inode = file_inode(file);
635 struct fuse_conn *fc = get_fuse_conn(inode);
636 struct fuse_req *req;
637 struct fuse_forget_in inarg;
638
639 memset(&inarg, 0, sizeof(inarg));
640 inarg.nlookup = 1;
641 req = fuse_get_req_nofail_nopages(fc, file);
642 req->in.h.opcode = FUSE_FORGET;
643 req->in.h.nodeid = nodeid;
644 req->in.numargs = 1;
645 req->in.args[0].size = sizeof(inarg);
646 req->in.args[0].value = &inarg;
647 __clear_bit(FR_ISREPLY, &req->flags);
648 __fuse_request_send(fc, req);
649 /* ignore errors */
650 fuse_put_request(fc, req);
651 }
652
653 /*
654 * Lock the request. Up to the next unlock_request() there mustn't be
655 * anything that could cause a page-fault. If the request was already
656 * aborted bail out.
657 */
658 static int lock_request(struct fuse_req *req)
659 {
660 int err = 0;
661 if (req) {
662 spin_lock(&req->waitq.lock);
663 if (test_bit(FR_ABORTED, &req->flags))
664 err = -ENOENT;
665 else
666 set_bit(FR_LOCKED, &req->flags);
667 spin_unlock(&req->waitq.lock);
668 }
669 return err;
670 }
671
672 /*
673 * Unlock request. If it was aborted while locked, caller is responsible
674 * for unlocking and ending the request.
675 */
676 static int unlock_request(struct fuse_req *req)
677 {
678 int err = 0;
679 if (req) {
680 spin_lock(&req->waitq.lock);
681 if (test_bit(FR_ABORTED, &req->flags))
682 err = -ENOENT;
683 else
684 clear_bit(FR_LOCKED, &req->flags);
685 spin_unlock(&req->waitq.lock);
686 }
687 return err;
688 }
689
690 struct fuse_copy_state {
691 int write;
692 struct fuse_req *req;
693 struct iov_iter *iter;
694 struct pipe_buffer *pipebufs;
695 struct pipe_buffer *currbuf;
696 struct pipe_inode_info *pipe;
697 unsigned long nr_segs;
698 struct page *pg;
699 unsigned len;
700 unsigned offset;
701 unsigned move_pages:1;
702 };
703
704 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
705 struct iov_iter *iter)
706 {
707 memset(cs, 0, sizeof(*cs));
708 cs->write = write;
709 cs->iter = iter;
710 }
711
712 /* Unmap and put previous page of userspace buffer */
713 static void fuse_copy_finish(struct fuse_copy_state *cs)
714 {
715 if (cs->currbuf) {
716 struct pipe_buffer *buf = cs->currbuf;
717
718 if (cs->write)
719 buf->len = PAGE_SIZE - cs->len;
720 cs->currbuf = NULL;
721 } else if (cs->pg) {
722 if (cs->write) {
723 flush_dcache_page(cs->pg);
724 set_page_dirty_lock(cs->pg);
725 }
726 put_page(cs->pg);
727 }
728 cs->pg = NULL;
729 }
730
731 /*
732 * Get another pagefull of userspace buffer, and map it to kernel
733 * address space, and lock request
734 */
735 static int fuse_copy_fill(struct fuse_copy_state *cs)
736 {
737 struct page *page;
738 int err;
739
740 err = unlock_request(cs->req);
741 if (err)
742 return err;
743
744 fuse_copy_finish(cs);
745 if (cs->pipebufs) {
746 struct pipe_buffer *buf = cs->pipebufs;
747
748 if (!cs->write) {
749 err = pipe_buf_confirm(cs->pipe, buf);
750 if (err)
751 return err;
752
753 BUG_ON(!cs->nr_segs);
754 cs->currbuf = buf;
755 cs->pg = buf->page;
756 cs->offset = buf->offset;
757 cs->len = buf->len;
758 cs->pipebufs++;
759 cs->nr_segs--;
760 } else {
761 if (cs->nr_segs == cs->pipe->buffers)
762 return -EIO;
763
764 page = alloc_page(GFP_HIGHUSER);
765 if (!page)
766 return -ENOMEM;
767
768 buf->page = page;
769 buf->offset = 0;
770 buf->len = 0;
771
772 cs->currbuf = buf;
773 cs->pg = page;
774 cs->offset = 0;
775 cs->len = PAGE_SIZE;
776 cs->pipebufs++;
777 cs->nr_segs++;
778 }
779 } else {
780 size_t off;
781 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
782 if (err < 0)
783 return err;
784 BUG_ON(!err);
785 cs->len = err;
786 cs->offset = off;
787 cs->pg = page;
788 iov_iter_advance(cs->iter, err);
789 }
790
791 return lock_request(cs->req);
792 }
793
794 /* Do as much copy to/from userspace buffer as we can */
795 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
796 {
797 unsigned ncpy = min(*size, cs->len);
798 if (val) {
799 void *pgaddr = kmap_atomic(cs->pg);
800 void *buf = pgaddr + cs->offset;
801
802 if (cs->write)
803 memcpy(buf, *val, ncpy);
804 else
805 memcpy(*val, buf, ncpy);
806
807 kunmap_atomic(pgaddr);
808 *val += ncpy;
809 }
810 *size -= ncpy;
811 cs->len -= ncpy;
812 cs->offset += ncpy;
813 return ncpy;
814 }
815
816 static int fuse_check_page(struct page *page)
817 {
818 if (page_mapcount(page) ||
819 page->mapping != NULL ||
820 page_count(page) != 1 ||
821 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
822 ~(1 << PG_locked |
823 1 << PG_referenced |
824 1 << PG_uptodate |
825 1 << PG_lru |
826 1 << PG_active |
827 1 << PG_reclaim))) {
828 printk(KERN_WARNING "fuse: trying to steal weird page\n");
829 printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
830 return 1;
831 }
832 return 0;
833 }
834
835 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
836 {
837 int err;
838 struct page *oldpage = *pagep;
839 struct page *newpage;
840 struct pipe_buffer *buf = cs->pipebufs;
841
842 err = unlock_request(cs->req);
843 if (err)
844 return err;
845
846 fuse_copy_finish(cs);
847
848 err = pipe_buf_confirm(cs->pipe, buf);
849 if (err)
850 return err;
851
852 BUG_ON(!cs->nr_segs);
853 cs->currbuf = buf;
854 cs->len = buf->len;
855 cs->pipebufs++;
856 cs->nr_segs--;
857
858 if (cs->len != PAGE_SIZE)
859 goto out_fallback;
860
861 if (pipe_buf_steal(cs->pipe, buf) != 0)
862 goto out_fallback;
863
864 newpage = buf->page;
865
866 if (!PageUptodate(newpage))
867 SetPageUptodate(newpage);
868
869 ClearPageMappedToDisk(newpage);
870
871 if (fuse_check_page(newpage) != 0)
872 goto out_fallback_unlock;
873
874 /*
875 * This is a new and locked page, it shouldn't be mapped or
876 * have any special flags on it
877 */
878 if (WARN_ON(page_mapped(oldpage)))
879 goto out_fallback_unlock;
880 if (WARN_ON(page_has_private(oldpage)))
881 goto out_fallback_unlock;
882 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
883 goto out_fallback_unlock;
884 if (WARN_ON(PageMlocked(oldpage)))
885 goto out_fallback_unlock;
886
887 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
888 if (err) {
889 unlock_page(newpage);
890 return err;
891 }
892
893 get_page(newpage);
894
895 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
896 lru_cache_add_file(newpage);
897
898 err = 0;
899 spin_lock(&cs->req->waitq.lock);
900 if (test_bit(FR_ABORTED, &cs->req->flags))
901 err = -ENOENT;
902 else
903 *pagep = newpage;
904 spin_unlock(&cs->req->waitq.lock);
905
906 if (err) {
907 unlock_page(newpage);
908 put_page(newpage);
909 return err;
910 }
911
912 unlock_page(oldpage);
913 put_page(oldpage);
914 cs->len = 0;
915
916 return 0;
917
918 out_fallback_unlock:
919 unlock_page(newpage);
920 out_fallback:
921 cs->pg = buf->page;
922 cs->offset = buf->offset;
923
924 err = lock_request(cs->req);
925 if (err)
926 return err;
927
928 return 1;
929 }
930
931 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
932 unsigned offset, unsigned count)
933 {
934 struct pipe_buffer *buf;
935 int err;
936
937 if (cs->nr_segs == cs->pipe->buffers)
938 return -EIO;
939
940 err = unlock_request(cs->req);
941 if (err)
942 return err;
943
944 fuse_copy_finish(cs);
945
946 buf = cs->pipebufs;
947 get_page(page);
948 buf->page = page;
949 buf->offset = offset;
950 buf->len = count;
951
952 cs->pipebufs++;
953 cs->nr_segs++;
954 cs->len = 0;
955
956 return 0;
957 }
958
959 /*
960 * Copy a page in the request to/from the userspace buffer. Must be
961 * done atomically
962 */
963 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
964 unsigned offset, unsigned count, int zeroing)
965 {
966 int err;
967 struct page *page = *pagep;
968
969 if (page && zeroing && count < PAGE_SIZE)
970 clear_highpage(page);
971
972 while (count) {
973 if (cs->write && cs->pipebufs && page) {
974 return fuse_ref_page(cs, page, offset, count);
975 } else if (!cs->len) {
976 if (cs->move_pages && page &&
977 offset == 0 && count == PAGE_SIZE) {
978 err = fuse_try_move_page(cs, pagep);
979 if (err <= 0)
980 return err;
981 } else {
982 err = fuse_copy_fill(cs);
983 if (err)
984 return err;
985 }
986 }
987 if (page) {
988 void *mapaddr = kmap_atomic(page);
989 void *buf = mapaddr + offset;
990 offset += fuse_copy_do(cs, &buf, &count);
991 kunmap_atomic(mapaddr);
992 } else
993 offset += fuse_copy_do(cs, NULL, &count);
994 }
995 if (page && !cs->write)
996 flush_dcache_page(page);
997 return 0;
998 }
999
1000 /* Copy pages in the request to/from userspace buffer */
1001 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1002 int zeroing)
1003 {
1004 unsigned i;
1005 struct fuse_req *req = cs->req;
1006
1007 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1008 int err;
1009 unsigned offset = req->page_descs[i].offset;
1010 unsigned count = min(nbytes, req->page_descs[i].length);
1011
1012 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1013 zeroing);
1014 if (err)
1015 return err;
1016
1017 nbytes -= count;
1018 }
1019 return 0;
1020 }
1021
1022 /* Copy a single argument in the request to/from userspace buffer */
1023 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1024 {
1025 while (size) {
1026 if (!cs->len) {
1027 int err = fuse_copy_fill(cs);
1028 if (err)
1029 return err;
1030 }
1031 fuse_copy_do(cs, &val, &size);
1032 }
1033 return 0;
1034 }
1035
1036 /* Copy request arguments to/from userspace buffer */
1037 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1038 unsigned argpages, struct fuse_arg *args,
1039 int zeroing)
1040 {
1041 int err = 0;
1042 unsigned i;
1043
1044 for (i = 0; !err && i < numargs; i++) {
1045 struct fuse_arg *arg = &args[i];
1046 if (i == numargs - 1 && argpages)
1047 err = fuse_copy_pages(cs, arg->size, zeroing);
1048 else
1049 err = fuse_copy_one(cs, arg->value, arg->size);
1050 }
1051 return err;
1052 }
1053
1054 static int forget_pending(struct fuse_iqueue *fiq)
1055 {
1056 return fiq->forget_list_head.next != NULL;
1057 }
1058
1059 static int request_pending(struct fuse_iqueue *fiq)
1060 {
1061 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1062 forget_pending(fiq);
1063 }
1064
1065 /*
1066 * Transfer an interrupt request to userspace
1067 *
1068 * Unlike other requests this is assembled on demand, without a need
1069 * to allocate a separate fuse_req structure.
1070 *
1071 * Called with fiq->waitq.lock held, releases it
1072 */
1073 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1074 struct fuse_copy_state *cs,
1075 size_t nbytes, struct fuse_req *req)
1076 __releases(fiq->waitq.lock)
1077 {
1078 struct fuse_in_header ih;
1079 struct fuse_interrupt_in arg;
1080 unsigned reqsize = sizeof(ih) + sizeof(arg);
1081 int err;
1082
1083 list_del_init(&req->intr_entry);
1084 req->intr_unique = fuse_get_unique(fiq);
1085 memset(&ih, 0, sizeof(ih));
1086 memset(&arg, 0, sizeof(arg));
1087 ih.len = reqsize;
1088 ih.opcode = FUSE_INTERRUPT;
1089 ih.unique = req->intr_unique;
1090 arg.unique = req->in.h.unique;
1091
1092 spin_unlock(&fiq->waitq.lock);
1093 if (nbytes < reqsize)
1094 return -EINVAL;
1095
1096 err = fuse_copy_one(cs, &ih, sizeof(ih));
1097 if (!err)
1098 err = fuse_copy_one(cs, &arg, sizeof(arg));
1099 fuse_copy_finish(cs);
1100
1101 return err ? err : reqsize;
1102 }
1103
1104 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1105 unsigned max,
1106 unsigned *countp)
1107 {
1108 struct fuse_forget_link *head = fiq->forget_list_head.next;
1109 struct fuse_forget_link **newhead = &head;
1110 unsigned count;
1111
1112 for (count = 0; *newhead != NULL && count < max; count++)
1113 newhead = &(*newhead)->next;
1114
1115 fiq->forget_list_head.next = *newhead;
1116 *newhead = NULL;
1117 if (fiq->forget_list_head.next == NULL)
1118 fiq->forget_list_tail = &fiq->forget_list_head;
1119
1120 if (countp != NULL)
1121 *countp = count;
1122
1123 return head;
1124 }
1125
1126 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1127 struct fuse_copy_state *cs,
1128 size_t nbytes)
1129 __releases(fiq->waitq.lock)
1130 {
1131 int err;
1132 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1133 struct fuse_forget_in arg = {
1134 .nlookup = forget->forget_one.nlookup,
1135 };
1136 struct fuse_in_header ih = {
1137 .opcode = FUSE_FORGET,
1138 .nodeid = forget->forget_one.nodeid,
1139 .unique = fuse_get_unique(fiq),
1140 .len = sizeof(ih) + sizeof(arg),
1141 };
1142
1143 spin_unlock(&fiq->waitq.lock);
1144 kfree(forget);
1145 if (nbytes < ih.len)
1146 return -EINVAL;
1147
1148 err = fuse_copy_one(cs, &ih, sizeof(ih));
1149 if (!err)
1150 err = fuse_copy_one(cs, &arg, sizeof(arg));
1151 fuse_copy_finish(cs);
1152
1153 if (err)
1154 return err;
1155
1156 return ih.len;
1157 }
1158
1159 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1160 struct fuse_copy_state *cs, size_t nbytes)
1161 __releases(fiq->waitq.lock)
1162 {
1163 int err;
1164 unsigned max_forgets;
1165 unsigned count;
1166 struct fuse_forget_link *head;
1167 struct fuse_batch_forget_in arg = { .count = 0 };
1168 struct fuse_in_header ih = {
1169 .opcode = FUSE_BATCH_FORGET,
1170 .unique = fuse_get_unique(fiq),
1171 .len = sizeof(ih) + sizeof(arg),
1172 };
1173
1174 if (nbytes < ih.len) {
1175 spin_unlock(&fiq->waitq.lock);
1176 return -EINVAL;
1177 }
1178
1179 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1180 head = dequeue_forget(fiq, max_forgets, &count);
1181 spin_unlock(&fiq->waitq.lock);
1182
1183 arg.count = count;
1184 ih.len += count * sizeof(struct fuse_forget_one);
1185 err = fuse_copy_one(cs, &ih, sizeof(ih));
1186 if (!err)
1187 err = fuse_copy_one(cs, &arg, sizeof(arg));
1188
1189 while (head) {
1190 struct fuse_forget_link *forget = head;
1191
1192 if (!err) {
1193 err = fuse_copy_one(cs, &forget->forget_one,
1194 sizeof(forget->forget_one));
1195 }
1196 head = forget->next;
1197 kfree(forget);
1198 }
1199
1200 fuse_copy_finish(cs);
1201
1202 if (err)
1203 return err;
1204
1205 return ih.len;
1206 }
1207
1208 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1209 struct fuse_copy_state *cs,
1210 size_t nbytes)
1211 __releases(fiq->waitq.lock)
1212 {
1213 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1214 return fuse_read_single_forget(fiq, cs, nbytes);
1215 else
1216 return fuse_read_batch_forget(fiq, cs, nbytes);
1217 }
1218
1219 /*
1220 * Read a single request into the userspace filesystem's buffer. This
1221 * function waits until a request is available, then removes it from
1222 * the pending list and copies request data to userspace buffer. If
1223 * no reply is needed (FORGET) or request has been aborted or there
1224 * was an error during the copying then it's finished by calling
1225 * request_end(). Otherwise add it to the processing list, and set
1226 * the 'sent' flag.
1227 */
1228 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1229 struct fuse_copy_state *cs, size_t nbytes)
1230 {
1231 ssize_t err;
1232 struct fuse_conn *fc = fud->fc;
1233 struct fuse_iqueue *fiq = &fc->iq;
1234 struct fuse_pqueue *fpq = &fud->pq;
1235 struct fuse_req *req;
1236 struct fuse_in *in;
1237 unsigned reqsize;
1238
1239 if (current_user_ns() != fc->user_ns)
1240 return -EIO;
1241
1242 restart:
1243 spin_lock(&fiq->waitq.lock);
1244 err = -EAGAIN;
1245 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1246 !request_pending(fiq))
1247 goto err_unlock;
1248
1249 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1250 !fiq->connected || request_pending(fiq));
1251 if (err)
1252 goto err_unlock;
1253
1254 err = -ENODEV;
1255 if (!fiq->connected)
1256 goto err_unlock;
1257
1258 if (!list_empty(&fiq->interrupts)) {
1259 req = list_entry(fiq->interrupts.next, struct fuse_req,
1260 intr_entry);
1261 return fuse_read_interrupt(fiq, cs, nbytes, req);
1262 }
1263
1264 if (forget_pending(fiq)) {
1265 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1266 return fuse_read_forget(fc, fiq, cs, nbytes);
1267
1268 if (fiq->forget_batch <= -8)
1269 fiq->forget_batch = 16;
1270 }
1271
1272 req = list_entry(fiq->pending.next, struct fuse_req, list);
1273 clear_bit(FR_PENDING, &req->flags);
1274 list_del_init(&req->list);
1275 spin_unlock(&fiq->waitq.lock);
1276
1277 in = &req->in;
1278 reqsize = in->h.len;
1279
1280 if (task_active_pid_ns(current) != fc->pid_ns) {
1281 rcu_read_lock();
1282 in->h.pid = pid_vnr(find_pid_ns(in->h.pid, fc->pid_ns));
1283 rcu_read_unlock();
1284 }
1285
1286 /* If request is too large, reply with an error and restart the read */
1287 if (nbytes < reqsize) {
1288 req->out.h.error = -EIO;
1289 /* SETXATTR is special, since it may contain too large data */
1290 if (in->h.opcode == FUSE_SETXATTR)
1291 req->out.h.error = -E2BIG;
1292 request_end(fc, req);
1293 goto restart;
1294 }
1295 spin_lock(&fpq->lock);
1296 list_add(&req->list, &fpq->io);
1297 spin_unlock(&fpq->lock);
1298 cs->req = req;
1299 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1300 if (!err)
1301 err = fuse_copy_args(cs, in->numargs, in->argpages,
1302 (struct fuse_arg *) in->args, 0);
1303 fuse_copy_finish(cs);
1304 spin_lock(&fpq->lock);
1305 clear_bit(FR_LOCKED, &req->flags);
1306 if (!fpq->connected) {
1307 err = -ENODEV;
1308 goto out_end;
1309 }
1310 if (err) {
1311 req->out.h.error = -EIO;
1312 goto out_end;
1313 }
1314 if (!test_bit(FR_ISREPLY, &req->flags)) {
1315 err = reqsize;
1316 goto out_end;
1317 }
1318 list_move_tail(&req->list, &fpq->processing);
1319 __fuse_get_request(req);
1320 spin_unlock(&fpq->lock);
1321 set_bit(FR_SENT, &req->flags);
1322 /* matches barrier in request_wait_answer() */
1323 smp_mb__after_atomic();
1324 if (test_bit(FR_INTERRUPTED, &req->flags))
1325 queue_interrupt(fiq, req);
1326 fuse_put_request(fc, req);
1327
1328 return reqsize;
1329
1330 out_end:
1331 if (!test_bit(FR_PRIVATE, &req->flags))
1332 list_del_init(&req->list);
1333 spin_unlock(&fpq->lock);
1334 request_end(fc, req);
1335 return err;
1336
1337 err_unlock:
1338 spin_unlock(&fiq->waitq.lock);
1339 return err;
1340 }
1341
1342 static int fuse_dev_open(struct inode *inode, struct file *file)
1343 {
1344 /*
1345 * The fuse device's file's private_data is used to hold
1346 * the fuse_conn(ection) when it is mounted, and is used to
1347 * keep track of whether the file has been mounted already.
1348 */
1349 file->private_data = NULL;
1350 return 0;
1351 }
1352
1353 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1354 {
1355 struct fuse_copy_state cs;
1356 struct file *file = iocb->ki_filp;
1357 struct fuse_dev *fud = fuse_get_dev(file);
1358
1359 if (!fud)
1360 return -EPERM;
1361
1362 if (!iter_is_iovec(to))
1363 return -EINVAL;
1364
1365 fuse_copy_init(&cs, 1, to);
1366
1367 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1368 }
1369
1370 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1371 struct pipe_inode_info *pipe,
1372 size_t len, unsigned int flags)
1373 {
1374 int total, ret;
1375 int page_nr = 0;
1376 struct pipe_buffer *bufs;
1377 struct fuse_copy_state cs;
1378 struct fuse_dev *fud = fuse_get_dev(in);
1379
1380 if (!fud)
1381 return -EPERM;
1382
1383 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1384 if (!bufs)
1385 return -ENOMEM;
1386
1387 fuse_copy_init(&cs, 1, NULL);
1388 cs.pipebufs = bufs;
1389 cs.pipe = pipe;
1390 ret = fuse_dev_do_read(fud, in, &cs, len);
1391 if (ret < 0)
1392 goto out;
1393
1394 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1395 ret = -EIO;
1396 goto out;
1397 }
1398
1399 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1400 /*
1401 * Need to be careful about this. Having buf->ops in module
1402 * code can Oops if the buffer persists after module unload.
1403 */
1404 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1405 bufs[page_nr].flags = 0;
1406 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1407 if (unlikely(ret < 0))
1408 break;
1409 }
1410 if (total)
1411 ret = total;
1412 out:
1413 for (; page_nr < cs.nr_segs; page_nr++)
1414 put_page(bufs[page_nr].page);
1415
1416 kfree(bufs);
1417 return ret;
1418 }
1419
1420 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1421 struct fuse_copy_state *cs)
1422 {
1423 struct fuse_notify_poll_wakeup_out outarg;
1424 int err = -EINVAL;
1425
1426 if (size != sizeof(outarg))
1427 goto err;
1428
1429 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1430 if (err)
1431 goto err;
1432
1433 fuse_copy_finish(cs);
1434 return fuse_notify_poll_wakeup(fc, &outarg);
1435
1436 err:
1437 fuse_copy_finish(cs);
1438 return err;
1439 }
1440
1441 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1442 struct fuse_copy_state *cs)
1443 {
1444 struct fuse_notify_inval_inode_out outarg;
1445 int err = -EINVAL;
1446
1447 if (size != sizeof(outarg))
1448 goto err;
1449
1450 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1451 if (err)
1452 goto err;
1453 fuse_copy_finish(cs);
1454
1455 down_read(&fc->killsb);
1456 err = -ENOENT;
1457 if (fc->sb) {
1458 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1459 outarg.off, outarg.len);
1460 }
1461 up_read(&fc->killsb);
1462 return err;
1463
1464 err:
1465 fuse_copy_finish(cs);
1466 return err;
1467 }
1468
1469 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1470 struct fuse_copy_state *cs)
1471 {
1472 struct fuse_notify_inval_entry_out outarg;
1473 int err = -ENOMEM;
1474 char *buf;
1475 struct qstr name;
1476
1477 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1478 if (!buf)
1479 goto err;
1480
1481 err = -EINVAL;
1482 if (size < sizeof(outarg))
1483 goto err;
1484
1485 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1486 if (err)
1487 goto err;
1488
1489 err = -ENAMETOOLONG;
1490 if (outarg.namelen > FUSE_NAME_MAX)
1491 goto err;
1492
1493 err = -EINVAL;
1494 if (size != sizeof(outarg) + outarg.namelen + 1)
1495 goto err;
1496
1497 name.name = buf;
1498 name.len = outarg.namelen;
1499 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1500 if (err)
1501 goto err;
1502 fuse_copy_finish(cs);
1503 buf[outarg.namelen] = 0;
1504
1505 down_read(&fc->killsb);
1506 err = -ENOENT;
1507 if (fc->sb)
1508 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1509 up_read(&fc->killsb);
1510 kfree(buf);
1511 return err;
1512
1513 err:
1514 kfree(buf);
1515 fuse_copy_finish(cs);
1516 return err;
1517 }
1518
1519 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1520 struct fuse_copy_state *cs)
1521 {
1522 struct fuse_notify_delete_out outarg;
1523 int err = -ENOMEM;
1524 char *buf;
1525 struct qstr name;
1526
1527 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1528 if (!buf)
1529 goto err;
1530
1531 err = -EINVAL;
1532 if (size < sizeof(outarg))
1533 goto err;
1534
1535 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1536 if (err)
1537 goto err;
1538
1539 err = -ENAMETOOLONG;
1540 if (outarg.namelen > FUSE_NAME_MAX)
1541 goto err;
1542
1543 err = -EINVAL;
1544 if (size != sizeof(outarg) + outarg.namelen + 1)
1545 goto err;
1546
1547 name.name = buf;
1548 name.len = outarg.namelen;
1549 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1550 if (err)
1551 goto err;
1552 fuse_copy_finish(cs);
1553 buf[outarg.namelen] = 0;
1554
1555 down_read(&fc->killsb);
1556 err = -ENOENT;
1557 if (fc->sb)
1558 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1559 outarg.child, &name);
1560 up_read(&fc->killsb);
1561 kfree(buf);
1562 return err;
1563
1564 err:
1565 kfree(buf);
1566 fuse_copy_finish(cs);
1567 return err;
1568 }
1569
1570 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1571 struct fuse_copy_state *cs)
1572 {
1573 struct fuse_notify_store_out outarg;
1574 struct inode *inode;
1575 struct address_space *mapping;
1576 u64 nodeid;
1577 int err;
1578 pgoff_t index;
1579 unsigned int offset;
1580 unsigned int num;
1581 loff_t file_size;
1582 loff_t end;
1583
1584 err = -EINVAL;
1585 if (size < sizeof(outarg))
1586 goto out_finish;
1587
1588 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1589 if (err)
1590 goto out_finish;
1591
1592 err = -EINVAL;
1593 if (size - sizeof(outarg) != outarg.size)
1594 goto out_finish;
1595
1596 nodeid = outarg.nodeid;
1597
1598 down_read(&fc->killsb);
1599
1600 err = -ENOENT;
1601 if (!fc->sb)
1602 goto out_up_killsb;
1603
1604 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1605 if (!inode)
1606 goto out_up_killsb;
1607
1608 mapping = inode->i_mapping;
1609 index = outarg.offset >> PAGE_SHIFT;
1610 offset = outarg.offset & ~PAGE_MASK;
1611 file_size = i_size_read(inode);
1612 end = outarg.offset + outarg.size;
1613 if (end > file_size) {
1614 file_size = end;
1615 fuse_write_update_size(inode, file_size);
1616 }
1617
1618 num = outarg.size;
1619 while (num) {
1620 struct page *page;
1621 unsigned int this_num;
1622
1623 err = -ENOMEM;
1624 page = find_or_create_page(mapping, index,
1625 mapping_gfp_mask(mapping));
1626 if (!page)
1627 goto out_iput;
1628
1629 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1630 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1631 if (!err && offset == 0 &&
1632 (this_num == PAGE_SIZE || file_size == end))
1633 SetPageUptodate(page);
1634 unlock_page(page);
1635 put_page(page);
1636
1637 if (err)
1638 goto out_iput;
1639
1640 num -= this_num;
1641 offset = 0;
1642 index++;
1643 }
1644
1645 err = 0;
1646
1647 out_iput:
1648 iput(inode);
1649 out_up_killsb:
1650 up_read(&fc->killsb);
1651 out_finish:
1652 fuse_copy_finish(cs);
1653 return err;
1654 }
1655
1656 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1657 {
1658 release_pages(req->pages, req->num_pages);
1659 }
1660
1661 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1662 struct fuse_notify_retrieve_out *outarg)
1663 {
1664 int err;
1665 struct address_space *mapping = inode->i_mapping;
1666 struct fuse_req *req;
1667 pgoff_t index;
1668 loff_t file_size;
1669 unsigned int num;
1670 unsigned int offset;
1671 size_t total_len = 0;
1672 int num_pages;
1673
1674 offset = outarg->offset & ~PAGE_MASK;
1675 file_size = i_size_read(inode);
1676
1677 num = outarg->size;
1678 if (outarg->offset > file_size)
1679 num = 0;
1680 else if (outarg->offset + num > file_size)
1681 num = file_size - outarg->offset;
1682
1683 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1684 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1685
1686 req = fuse_get_req(fc, num_pages);
1687 if (IS_ERR(req))
1688 return PTR_ERR(req);
1689
1690 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1691 req->in.h.nodeid = outarg->nodeid;
1692 req->in.numargs = 2;
1693 req->in.argpages = 1;
1694 req->page_descs[0].offset = offset;
1695 req->end = fuse_retrieve_end;
1696
1697 index = outarg->offset >> PAGE_SHIFT;
1698
1699 while (num && req->num_pages < num_pages) {
1700 struct page *page;
1701 unsigned int this_num;
1702
1703 page = find_get_page(mapping, index);
1704 if (!page)
1705 break;
1706
1707 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1708 req->pages[req->num_pages] = page;
1709 req->page_descs[req->num_pages].length = this_num;
1710 req->num_pages++;
1711
1712 offset = 0;
1713 num -= this_num;
1714 total_len += this_num;
1715 index++;
1716 }
1717 req->misc.retrieve_in.offset = outarg->offset;
1718 req->misc.retrieve_in.size = total_len;
1719 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1720 req->in.args[0].value = &req->misc.retrieve_in;
1721 req->in.args[1].size = total_len;
1722
1723 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1724 if (err)
1725 fuse_retrieve_end(fc, req);
1726
1727 return err;
1728 }
1729
1730 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1731 struct fuse_copy_state *cs)
1732 {
1733 struct fuse_notify_retrieve_out outarg;
1734 struct inode *inode;
1735 int err;
1736
1737 err = -EINVAL;
1738 if (size != sizeof(outarg))
1739 goto copy_finish;
1740
1741 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1742 if (err)
1743 goto copy_finish;
1744
1745 fuse_copy_finish(cs);
1746
1747 down_read(&fc->killsb);
1748 err = -ENOENT;
1749 if (fc->sb) {
1750 u64 nodeid = outarg.nodeid;
1751
1752 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1753 if (inode) {
1754 err = fuse_retrieve(fc, inode, &outarg);
1755 iput(inode);
1756 }
1757 }
1758 up_read(&fc->killsb);
1759
1760 return err;
1761
1762 copy_finish:
1763 fuse_copy_finish(cs);
1764 return err;
1765 }
1766
1767 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1768 unsigned int size, struct fuse_copy_state *cs)
1769 {
1770 /* Don't try to move pages (yet) */
1771 cs->move_pages = 0;
1772
1773 switch (code) {
1774 case FUSE_NOTIFY_POLL:
1775 return fuse_notify_poll(fc, size, cs);
1776
1777 case FUSE_NOTIFY_INVAL_INODE:
1778 return fuse_notify_inval_inode(fc, size, cs);
1779
1780 case FUSE_NOTIFY_INVAL_ENTRY:
1781 return fuse_notify_inval_entry(fc, size, cs);
1782
1783 case FUSE_NOTIFY_STORE:
1784 return fuse_notify_store(fc, size, cs);
1785
1786 case FUSE_NOTIFY_RETRIEVE:
1787 return fuse_notify_retrieve(fc, size, cs);
1788
1789 case FUSE_NOTIFY_DELETE:
1790 return fuse_notify_delete(fc, size, cs);
1791
1792 default:
1793 fuse_copy_finish(cs);
1794 return -EINVAL;
1795 }
1796 }
1797
1798 /* Look up request on processing list by unique ID */
1799 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1800 {
1801 struct fuse_req *req;
1802
1803 list_for_each_entry(req, &fpq->processing, list) {
1804 if (req->in.h.unique == unique || req->intr_unique == unique)
1805 return req;
1806 }
1807 return NULL;
1808 }
1809
1810 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1811 unsigned nbytes)
1812 {
1813 unsigned reqsize = sizeof(struct fuse_out_header);
1814
1815 if (out->h.error)
1816 return nbytes != reqsize ? -EINVAL : 0;
1817
1818 reqsize += len_args(out->numargs, out->args);
1819
1820 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1821 return -EINVAL;
1822 else if (reqsize > nbytes) {
1823 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1824 unsigned diffsize = reqsize - nbytes;
1825 if (diffsize > lastarg->size)
1826 return -EINVAL;
1827 lastarg->size -= diffsize;
1828 }
1829 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1830 out->page_zeroing);
1831 }
1832
1833 /*
1834 * Write a single reply to a request. First the header is copied from
1835 * the write buffer. The request is then searched on the processing
1836 * list by the unique ID found in the header. If found, then remove
1837 * it from the list and copy the rest of the buffer to the request.
1838 * The request is finished by calling request_end()
1839 */
1840 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1841 struct fuse_copy_state *cs, size_t nbytes)
1842 {
1843 int err;
1844 struct fuse_conn *fc = fud->fc;
1845 struct fuse_pqueue *fpq = &fud->pq;
1846 struct fuse_req *req;
1847 struct fuse_out_header oh;
1848
1849 if (current_user_ns() != fc->user_ns)
1850 return -EIO;
1851
1852 if (nbytes < sizeof(struct fuse_out_header))
1853 return -EINVAL;
1854
1855 err = fuse_copy_one(cs, &oh, sizeof(oh));
1856 if (err)
1857 goto err_finish;
1858
1859 err = -EINVAL;
1860 if (oh.len != nbytes)
1861 goto err_finish;
1862
1863 /*
1864 * Zero oh.unique indicates unsolicited notification message
1865 * and error contains notification code.
1866 */
1867 if (!oh.unique) {
1868 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1869 return err ? err : nbytes;
1870 }
1871
1872 err = -EINVAL;
1873 if (oh.error <= -1000 || oh.error > 0)
1874 goto err_finish;
1875
1876 spin_lock(&fpq->lock);
1877 err = -ENOENT;
1878 if (!fpq->connected)
1879 goto err_unlock_pq;
1880
1881 req = request_find(fpq, oh.unique);
1882 if (!req)
1883 goto err_unlock_pq;
1884
1885 /* Is it an interrupt reply? */
1886 if (req->intr_unique == oh.unique) {
1887 __fuse_get_request(req);
1888 spin_unlock(&fpq->lock);
1889
1890 err = -EINVAL;
1891 if (nbytes != sizeof(struct fuse_out_header)) {
1892 fuse_put_request(fc, req);
1893 goto err_finish;
1894 }
1895
1896 if (oh.error == -ENOSYS)
1897 fc->no_interrupt = 1;
1898 else if (oh.error == -EAGAIN)
1899 queue_interrupt(&fc->iq, req);
1900 fuse_put_request(fc, req);
1901
1902 fuse_copy_finish(cs);
1903 return nbytes;
1904 }
1905
1906 clear_bit(FR_SENT, &req->flags);
1907 list_move(&req->list, &fpq->io);
1908 req->out.h = oh;
1909 set_bit(FR_LOCKED, &req->flags);
1910 spin_unlock(&fpq->lock);
1911 cs->req = req;
1912 if (!req->out.page_replace)
1913 cs->move_pages = 0;
1914
1915 err = copy_out_args(cs, &req->out, nbytes);
1916 fuse_copy_finish(cs);
1917
1918 spin_lock(&fpq->lock);
1919 clear_bit(FR_LOCKED, &req->flags);
1920 if (!fpq->connected)
1921 err = -ENOENT;
1922 else if (err)
1923 req->out.h.error = -EIO;
1924 if (!test_bit(FR_PRIVATE, &req->flags))
1925 list_del_init(&req->list);
1926 spin_unlock(&fpq->lock);
1927
1928 request_end(fc, req);
1929
1930 return err ? err : nbytes;
1931
1932 err_unlock_pq:
1933 spin_unlock(&fpq->lock);
1934 err_finish:
1935 fuse_copy_finish(cs);
1936 return err;
1937 }
1938
1939 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1940 {
1941 struct fuse_copy_state cs;
1942 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1943
1944 if (!fud)
1945 return -EPERM;
1946
1947 if (!iter_is_iovec(from))
1948 return -EINVAL;
1949
1950 fuse_copy_init(&cs, 0, from);
1951
1952 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1953 }
1954
1955 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1956 struct file *out, loff_t *ppos,
1957 size_t len, unsigned int flags)
1958 {
1959 unsigned nbuf;
1960 unsigned idx;
1961 struct pipe_buffer *bufs;
1962 struct fuse_copy_state cs;
1963 struct fuse_dev *fud;
1964 size_t rem;
1965 ssize_t ret;
1966
1967 fud = fuse_get_dev(out);
1968 if (!fud)
1969 return -EPERM;
1970
1971 pipe_lock(pipe);
1972
1973 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1974 if (!bufs) {
1975 pipe_unlock(pipe);
1976 return -ENOMEM;
1977 }
1978
1979 nbuf = 0;
1980 rem = 0;
1981 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1982 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1983
1984 ret = -EINVAL;
1985 if (rem < len) {
1986 pipe_unlock(pipe);
1987 goto out;
1988 }
1989
1990 rem = len;
1991 while (rem) {
1992 struct pipe_buffer *ibuf;
1993 struct pipe_buffer *obuf;
1994
1995 BUG_ON(nbuf >= pipe->buffers);
1996 BUG_ON(!pipe->nrbufs);
1997 ibuf = &pipe->bufs[pipe->curbuf];
1998 obuf = &bufs[nbuf];
1999
2000 if (rem >= ibuf->len) {
2001 *obuf = *ibuf;
2002 ibuf->ops = NULL;
2003 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2004 pipe->nrbufs--;
2005 } else {
2006 pipe_buf_get(pipe, ibuf);
2007 *obuf = *ibuf;
2008 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2009 obuf->len = rem;
2010 ibuf->offset += obuf->len;
2011 ibuf->len -= obuf->len;
2012 }
2013 nbuf++;
2014 rem -= obuf->len;
2015 }
2016 pipe_unlock(pipe);
2017
2018 fuse_copy_init(&cs, 0, NULL);
2019 cs.pipebufs = bufs;
2020 cs.nr_segs = nbuf;
2021 cs.pipe = pipe;
2022
2023 if (flags & SPLICE_F_MOVE)
2024 cs.move_pages = 1;
2025
2026 ret = fuse_dev_do_write(fud, &cs, len);
2027
2028 for (idx = 0; idx < nbuf; idx++)
2029 pipe_buf_release(pipe, &bufs[idx]);
2030
2031 out:
2032 kfree(bufs);
2033 return ret;
2034 }
2035
2036 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2037 {
2038 unsigned mask = POLLOUT | POLLWRNORM;
2039 struct fuse_iqueue *fiq;
2040 struct fuse_dev *fud = fuse_get_dev(file);
2041
2042 if (!fud)
2043 return POLLERR;
2044
2045 fiq = &fud->fc->iq;
2046 poll_wait(file, &fiq->waitq, wait);
2047
2048 spin_lock(&fiq->waitq.lock);
2049 if (!fiq->connected)
2050 mask = POLLERR;
2051 else if (request_pending(fiq))
2052 mask |= POLLIN | POLLRDNORM;
2053 spin_unlock(&fiq->waitq.lock);
2054
2055 return mask;
2056 }
2057
2058 /*
2059 * Abort all requests on the given list (pending or processing)
2060 *
2061 * This function releases and reacquires fc->lock
2062 */
2063 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2064 {
2065 while (!list_empty(head)) {
2066 struct fuse_req *req;
2067 req = list_entry(head->next, struct fuse_req, list);
2068 req->out.h.error = -ECONNABORTED;
2069 clear_bit(FR_SENT, &req->flags);
2070 list_del_init(&req->list);
2071 request_end(fc, req);
2072 }
2073 }
2074
2075 static void end_polls(struct fuse_conn *fc)
2076 {
2077 struct rb_node *p;
2078
2079 p = rb_first(&fc->polled_files);
2080
2081 while (p) {
2082 struct fuse_file *ff;
2083 ff = rb_entry(p, struct fuse_file, polled_node);
2084 wake_up_interruptible_all(&ff->poll_wait);
2085
2086 p = rb_next(p);
2087 }
2088 }
2089
2090 /*
2091 * Abort all requests.
2092 *
2093 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2094 * filesystem.
2095 *
2096 * The same effect is usually achievable through killing the filesystem daemon
2097 * and all users of the filesystem. The exception is the combination of an
2098 * asynchronous request and the tricky deadlock (see
2099 * Documentation/filesystems/fuse.txt).
2100 *
2101 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2102 * requests, they should be finished off immediately. Locked requests will be
2103 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2104 * requests. It is possible that some request will finish before we can. This
2105 * is OK, the request will in that case be removed from the list before we touch
2106 * it.
2107 */
2108 void fuse_abort_conn(struct fuse_conn *fc)
2109 {
2110 struct fuse_iqueue *fiq = &fc->iq;
2111
2112 spin_lock(&fc->lock);
2113 if (fc->connected) {
2114 struct fuse_dev *fud;
2115 struct fuse_req *req, *next;
2116 LIST_HEAD(to_end1);
2117 LIST_HEAD(to_end2);
2118
2119 fc->connected = 0;
2120 fc->blocked = 0;
2121 fuse_set_initialized(fc);
2122 list_for_each_entry(fud, &fc->devices, entry) {
2123 struct fuse_pqueue *fpq = &fud->pq;
2124
2125 spin_lock(&fpq->lock);
2126 fpq->connected = 0;
2127 list_for_each_entry_safe(req, next, &fpq->io, list) {
2128 req->out.h.error = -ECONNABORTED;
2129 spin_lock(&req->waitq.lock);
2130 set_bit(FR_ABORTED, &req->flags);
2131 if (!test_bit(FR_LOCKED, &req->flags)) {
2132 set_bit(FR_PRIVATE, &req->flags);
2133 __fuse_get_request(req);
2134 list_move(&req->list, &to_end1);
2135 }
2136 spin_unlock(&req->waitq.lock);
2137 }
2138 list_splice_init(&fpq->processing, &to_end2);
2139 spin_unlock(&fpq->lock);
2140 }
2141 fc->max_background = UINT_MAX;
2142 flush_bg_queue(fc);
2143
2144 spin_lock(&fiq->waitq.lock);
2145 fiq->connected = 0;
2146 list_splice_init(&fiq->pending, &to_end2);
2147 list_for_each_entry(req, &to_end2, list)
2148 clear_bit(FR_PENDING, &req->flags);
2149 while (forget_pending(fiq))
2150 kfree(dequeue_forget(fiq, 1, NULL));
2151 wake_up_all_locked(&fiq->waitq);
2152 spin_unlock(&fiq->waitq.lock);
2153 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2154 end_polls(fc);
2155 wake_up_all(&fc->blocked_waitq);
2156 spin_unlock(&fc->lock);
2157
2158 while (!list_empty(&to_end1)) {
2159 req = list_first_entry(&to_end1, struct fuse_req, list);
2160 list_del_init(&req->list);
2161 request_end(fc, req);
2162 }
2163 end_requests(fc, &to_end2);
2164 } else {
2165 spin_unlock(&fc->lock);
2166 }
2167 }
2168 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2169
2170 void fuse_wait_aborted(struct fuse_conn *fc)
2171 {
2172 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2173 }
2174
2175 int fuse_dev_release(struct inode *inode, struct file *file)
2176 {
2177 struct fuse_dev *fud = fuse_get_dev(file);
2178
2179 if (fud) {
2180 struct fuse_conn *fc = fud->fc;
2181 struct fuse_pqueue *fpq = &fud->pq;
2182 LIST_HEAD(to_end);
2183
2184 spin_lock(&fpq->lock);
2185 WARN_ON(!list_empty(&fpq->io));
2186 list_splice_init(&fpq->processing, &to_end);
2187 spin_unlock(&fpq->lock);
2188
2189 end_requests(fc, &to_end);
2190
2191 /* Are we the last open device? */
2192 if (atomic_dec_and_test(&fc->dev_count)) {
2193 WARN_ON(fc->iq.fasync != NULL);
2194 fuse_abort_conn(fc);
2195 }
2196 fuse_dev_free(fud);
2197 }
2198 return 0;
2199 }
2200 EXPORT_SYMBOL_GPL(fuse_dev_release);
2201
2202 static int fuse_dev_fasync(int fd, struct file *file, int on)
2203 {
2204 struct fuse_dev *fud = fuse_get_dev(file);
2205
2206 if (!fud)
2207 return -EPERM;
2208
2209 /* No locking - fasync_helper does its own locking */
2210 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2211 }
2212
2213 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2214 {
2215 struct fuse_dev *fud;
2216
2217 if (new->private_data)
2218 return -EINVAL;
2219
2220 fud = fuse_dev_alloc(fc);
2221 if (!fud)
2222 return -ENOMEM;
2223
2224 new->private_data = fud;
2225 atomic_inc(&fc->dev_count);
2226
2227 return 0;
2228 }
2229
2230 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2231 unsigned long arg)
2232 {
2233 int err = -ENOTTY;
2234
2235 if (cmd == FUSE_DEV_IOC_CLONE) {
2236 int oldfd;
2237
2238 err = -EFAULT;
2239 if (!get_user(oldfd, (__u32 __user *) arg)) {
2240 struct file *old = fget(oldfd);
2241
2242 err = -EINVAL;
2243 if (old) {
2244 struct fuse_dev *fud = NULL;
2245
2246 /*
2247 * Check against file->f_op because CUSE
2248 * uses the same ioctl handler.
2249 */
2250 if (old->f_op == file->f_op &&
2251 old->f_cred->user_ns == file->f_cred->user_ns)
2252 fud = fuse_get_dev(old);
2253
2254 if (fud) {
2255 mutex_lock(&fuse_mutex);
2256 err = fuse_device_clone(fud->fc, file);
2257 mutex_unlock(&fuse_mutex);
2258 }
2259 fput(old);
2260 }
2261 }
2262 }
2263 return err;
2264 }
2265
2266 const struct file_operations fuse_dev_operations = {
2267 .owner = THIS_MODULE,
2268 .open = fuse_dev_open,
2269 .llseek = no_llseek,
2270 .read_iter = fuse_dev_read,
2271 .splice_read = fuse_dev_splice_read,
2272 .write_iter = fuse_dev_write,
2273 .splice_write = fuse_dev_splice_write,
2274 .poll = fuse_dev_poll,
2275 .release = fuse_dev_release,
2276 .fasync = fuse_dev_fasync,
2277 .unlocked_ioctl = fuse_dev_ioctl,
2278 .compat_ioctl = fuse_dev_ioctl,
2279 };
2280 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2281
2282 static struct miscdevice fuse_miscdevice = {
2283 .minor = FUSE_MINOR,
2284 .name = "fuse",
2285 .fops = &fuse_dev_operations,
2286 };
2287
2288 int __init fuse_dev_init(void)
2289 {
2290 int err = -ENOMEM;
2291 fuse_req_cachep = kmem_cache_create("fuse_request",
2292 sizeof(struct fuse_req),
2293 0, 0, NULL);
2294 if (!fuse_req_cachep)
2295 goto out;
2296
2297 err = misc_register(&fuse_miscdevice);
2298 if (err)
2299 goto out_cache_clean;
2300
2301 return 0;
2302
2303 out_cache_clean:
2304 kmem_cache_destroy(fuse_req_cachep);
2305 out:
2306 return err;
2307 }
2308
2309 void fuse_dev_cleanup(void)
2310 {
2311 misc_deregister(&fuse_miscdevice);
2312 kmem_cache_destroy(fuse_req_cachep);
2313 }
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