projects/linux·blob v5.13 · refs

2315 lines · 51.7 KiB

1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <[email protected]>
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
25MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26MODULE_ALIAS("devname:fuse");
27
28/* Ordinary requests have even IDs, while interrupts IDs are odd */
29#define FUSE_INT_REQ_BIT (1ULL << 0)
30#define FUSE_REQ_ID_STEP (1ULL << 1)
31
32static struct kmem_cache *fuse_req_cachep;
33
34static struct fuse_dev *fuse_get_dev(struct file *file)
35{
36 /*
37 * Lockless access is OK, because file->private data is set
38 * once during mount and is valid until the file is released.
39 */
40 return READ_ONCE(file->private_data);
41}
42
43static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
44{
45 INIT_LIST_HEAD(&req->list);
46 INIT_LIST_HEAD(&req->intr_entry);
47 init_waitqueue_head(&req->waitq);
48 refcount_set(&req->count, 1);
49 __set_bit(FR_PENDING, &req->flags);
50 req->fm = fm;
51}
52
53static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags)
54{
55 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
56 if (req)
57 fuse_request_init(fm, req);
58
59 return req;
60}
61
62static void fuse_request_free(struct fuse_req *req)
63{
64 kmem_cache_free(fuse_req_cachep, req);
65}
66
67static void __fuse_get_request(struct fuse_req *req)
68{
69 refcount_inc(&req->count);
70}
71
72/* Must be called with > 1 refcount */
73static void __fuse_put_request(struct fuse_req *req)
74{
75 refcount_dec(&req->count);
76}
77
78void fuse_set_initialized(struct fuse_conn *fc)
79{
80 /* Make sure stores before this are seen on another CPU */
81 smp_wmb();
82 fc->initialized = 1;
83}
84
85static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
86{
87 return !fc->initialized || (for_background && fc->blocked);
88}
89
90static void fuse_drop_waiting(struct fuse_conn *fc)
91{
92 /*
93 * lockess check of fc->connected is okay, because atomic_dec_and_test()
94 * provides a memory barrier mached with the one in fuse_wait_aborted()
95 * to ensure no wake-up is missed.
96 */
97 if (atomic_dec_and_test(&fc->num_waiting) &&
98 !READ_ONCE(fc->connected)) {
99 /* wake up aborters */
100 wake_up_all(&fc->blocked_waitq);
101 }
102}
103
104static void fuse_put_request(struct fuse_req *req);
105
106static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background)
107{
108 struct fuse_conn *fc = fm->fc;
109 struct fuse_req *req;
110 int err;
111 atomic_inc(&fc->num_waiting);
112
113 if (fuse_block_alloc(fc, for_background)) {
114 err = -EINTR;
115 if (wait_event_killable_exclusive(fc->blocked_waitq,
116 !fuse_block_alloc(fc, for_background)))
117 goto out;
118 }
119 /* Matches smp_wmb() in fuse_set_initialized() */
120 smp_rmb();
121
122 err = -ENOTCONN;
123 if (!fc->connected)
124 goto out;
125
126 err = -ECONNREFUSED;
127 if (fc->conn_error)
128 goto out;
129
130 req = fuse_request_alloc(fm, GFP_KERNEL);
131 err = -ENOMEM;
132 if (!req) {
133 if (for_background)
134 wake_up(&fc->blocked_waitq);
135 goto out;
136 }
137
138 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
139 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
140 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
141
142 __set_bit(FR_WAITING, &req->flags);
143 if (for_background)
144 __set_bit(FR_BACKGROUND, &req->flags);
145
146 if (unlikely(req->in.h.uid == ((uid_t)-1) ||
147 req->in.h.gid == ((gid_t)-1))) {
148 fuse_put_request(req);
149 return ERR_PTR(-EOVERFLOW);
150 }
151 return req;
152
153 out:
154 fuse_drop_waiting(fc);
155 return ERR_PTR(err);
156}
157
158static void fuse_put_request(struct fuse_req *req)
159{
160 struct fuse_conn *fc = req->fm->fc;
161
162 if (refcount_dec_and_test(&req->count)) {
163 if (test_bit(FR_BACKGROUND, &req->flags)) {
164 /*
165 * We get here in the unlikely case that a background
166 * request was allocated but not sent
167 */
168 spin_lock(&fc->bg_lock);
169 if (!fc->blocked)
170 wake_up(&fc->blocked_waitq);
171 spin_unlock(&fc->bg_lock);
172 }
173
174 if (test_bit(FR_WAITING, &req->flags)) {
175 __clear_bit(FR_WAITING, &req->flags);
176 fuse_drop_waiting(fc);
177 }
178
179 fuse_request_free(req);
180 }
181}
182
183unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
184{
185 unsigned nbytes = 0;
186 unsigned i;
187
188 for (i = 0; i < numargs; i++)
189 nbytes += args[i].size;
190
191 return nbytes;
192}
193EXPORT_SYMBOL_GPL(fuse_len_args);
194
195u64 fuse_get_unique(struct fuse_iqueue *fiq)
196{
197 fiq->reqctr += FUSE_REQ_ID_STEP;
198 return fiq->reqctr;
199}
200EXPORT_SYMBOL_GPL(fuse_get_unique);
201
202static unsigned int fuse_req_hash(u64 unique)
203{
204 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
205}
206
207/**
208 * A new request is available, wake fiq->waitq
209 */
210static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
211__releases(fiq->lock)
212{
213 wake_up(&fiq->waitq);
214 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
215 spin_unlock(&fiq->lock);
216}
217
218const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
219 .wake_forget_and_unlock = fuse_dev_wake_and_unlock,
220 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock,
221 .wake_pending_and_unlock = fuse_dev_wake_and_unlock,
222};
223EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
224
225static void queue_request_and_unlock(struct fuse_iqueue *fiq,
226 struct fuse_req *req)
227__releases(fiq->lock)
228{
229 req->in.h.len = sizeof(struct fuse_in_header) +
230 fuse_len_args(req->args->in_numargs,
231 (struct fuse_arg *) req->args->in_args);
232 list_add_tail(&req->list, &fiq->pending);
233 fiq->ops->wake_pending_and_unlock(fiq);
234}
235
236void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
237 u64 nodeid, u64 nlookup)
238{
239 struct fuse_iqueue *fiq = &fc->iq;
240
241 forget->forget_one.nodeid = nodeid;
242 forget->forget_one.nlookup = nlookup;
243
244 spin_lock(&fiq->lock);
245 if (fiq->connected) {
246 fiq->forget_list_tail->next = forget;
247 fiq->forget_list_tail = forget;
248 fiq->ops->wake_forget_and_unlock(fiq);
249 } else {
250 kfree(forget);
251 spin_unlock(&fiq->lock);
252 }
253}
254
255static void flush_bg_queue(struct fuse_conn *fc)
256{
257 struct fuse_iqueue *fiq = &fc->iq;
258
259 while (fc->active_background < fc->max_background &&
260 !list_empty(&fc->bg_queue)) {
261 struct fuse_req *req;
262
263 req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
264 list_del(&req->list);
265 fc->active_background++;
266 spin_lock(&fiq->lock);
267 req->in.h.unique = fuse_get_unique(fiq);
268 queue_request_and_unlock(fiq, req);
269 }
270}
271
272/*
273 * This function is called when a request is finished. Either a reply
274 * has arrived or it was aborted (and not yet sent) or some error
275 * occurred during communication with userspace, or the device file
276 * was closed. The requester thread is woken up (if still waiting),
277 * the 'end' callback is called if given, else the reference to the
278 * request is released
279 */
280void fuse_request_end(struct fuse_req *req)
281{
282 struct fuse_mount *fm = req->fm;
283 struct fuse_conn *fc = fm->fc;
284 struct fuse_iqueue *fiq = &fc->iq;
285
286 if (test_and_set_bit(FR_FINISHED, &req->flags))
287 goto put_request;
288
289 /*
290 * test_and_set_bit() implies smp_mb() between bit
291 * changing and below intr_entry check. Pairs with
292 * smp_mb() from queue_interrupt().
293 */
294 if (!list_empty(&req->intr_entry)) {
295 spin_lock(&fiq->lock);
296 list_del_init(&req->intr_entry);
297 spin_unlock(&fiq->lock);
298 }
299 WARN_ON(test_bit(FR_PENDING, &req->flags));
300 WARN_ON(test_bit(FR_SENT, &req->flags));
301 if (test_bit(FR_BACKGROUND, &req->flags)) {
302 spin_lock(&fc->bg_lock);
303 clear_bit(FR_BACKGROUND, &req->flags);
304 if (fc->num_background == fc->max_background) {
305 fc->blocked = 0;
306 wake_up(&fc->blocked_waitq);
307 } else if (!fc->blocked) {
308 /*
309 * Wake up next waiter, if any. It's okay to use
310 * waitqueue_active(), as we've already synced up
311 * fc->blocked with waiters with the wake_up() call
312 * above.
313 */
314 if (waitqueue_active(&fc->blocked_waitq))
315 wake_up(&fc->blocked_waitq);
316 }
317
318 if (fc->num_background == fc->congestion_threshold && fm->sb) {
319 clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
320 clear_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC);
321 }
322 fc->num_background--;
323 fc->active_background--;
324 flush_bg_queue(fc);
325 spin_unlock(&fc->bg_lock);
326 } else {
327 /* Wake up waiter sleeping in request_wait_answer() */
328 wake_up(&req->waitq);
329 }
330
331 if (test_bit(FR_ASYNC, &req->flags))
332 req->args->end(fm, req->args, req->out.h.error);
333put_request:
334 fuse_put_request(req);
335}
336EXPORT_SYMBOL_GPL(fuse_request_end);
337
338static int queue_interrupt(struct fuse_req *req)
339{
340 struct fuse_iqueue *fiq = &req->fm->fc->iq;
341
342 spin_lock(&fiq->lock);
343 /* Check for we've sent request to interrupt this req */
344 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
345 spin_unlock(&fiq->lock);
346 return -EINVAL;
347 }
348
349 if (list_empty(&req->intr_entry)) {
350 list_add_tail(&req->intr_entry, &fiq->interrupts);
351 /*
352 * Pairs with smp_mb() implied by test_and_set_bit()
353 * from fuse_request_end().
354 */
355 smp_mb();
356 if (test_bit(FR_FINISHED, &req->flags)) {
357 list_del_init(&req->intr_entry);
358 spin_unlock(&fiq->lock);
359 return 0;
360 }
361 fiq->ops->wake_interrupt_and_unlock(fiq);
362 } else {
363 spin_unlock(&fiq->lock);
364 }
365 return 0;
366}
367
368static void request_wait_answer(struct fuse_req *req)
369{
370 struct fuse_conn *fc = req->fm->fc;
371 struct fuse_iqueue *fiq = &fc->iq;
372 int err;
373
374 if (!fc->no_interrupt) {
375 /* Any signal may interrupt this */
376 err = wait_event_interruptible(req->waitq,
377 test_bit(FR_FINISHED, &req->flags));
378 if (!err)
379 return;
380
381 set_bit(FR_INTERRUPTED, &req->flags);
382 /* matches barrier in fuse_dev_do_read() */
383 smp_mb__after_atomic();
384 if (test_bit(FR_SENT, &req->flags))
385 queue_interrupt(req);
386 }
387
388 if (!test_bit(FR_FORCE, &req->flags)) {
389 /* Only fatal signals may interrupt this */
390 err = wait_event_killable(req->waitq,
391 test_bit(FR_FINISHED, &req->flags));
392 if (!err)
393 return;
394
395 spin_lock(&fiq->lock);
396 /* Request is not yet in userspace, bail out */
397 if (test_bit(FR_PENDING, &req->flags)) {
398 list_del(&req->list);
399 spin_unlock(&fiq->lock);
400 __fuse_put_request(req);
401 req->out.h.error = -EINTR;
402 return;
403 }
404 spin_unlock(&fiq->lock);
405 }
406
407 /*
408 * Either request is already in userspace, or it was forced.
409 * Wait it out.
410 */
411 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
412}
413
414static void __fuse_request_send(struct fuse_req *req)
415{
416 struct fuse_iqueue *fiq = &req->fm->fc->iq;
417
418 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
419 spin_lock(&fiq->lock);
420 if (!fiq->connected) {
421 spin_unlock(&fiq->lock);
422 req->out.h.error = -ENOTCONN;
423 } else {
424 req->in.h.unique = fuse_get_unique(fiq);
425 /* acquire extra reference, since request is still needed
426 after fuse_request_end() */
427 __fuse_get_request(req);
428 queue_request_and_unlock(fiq, req);
429
430 request_wait_answer(req);
431 /* Pairs with smp_wmb() in fuse_request_end() */
432 smp_rmb();
433 }
434}
435
436static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
437{
438 if (fc->minor < 4 && args->opcode == FUSE_STATFS)
439 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
440
441 if (fc->minor < 9) {
442 switch (args->opcode) {
443 case FUSE_LOOKUP:
444 case FUSE_CREATE:
445 case FUSE_MKNOD:
446 case FUSE_MKDIR:
447 case FUSE_SYMLINK:
448 case FUSE_LINK:
449 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
450 break;
451 case FUSE_GETATTR:
452 case FUSE_SETATTR:
453 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
454 break;
455 }
456 }
457 if (fc->minor < 12) {
458 switch (args->opcode) {
459 case FUSE_CREATE:
460 args->in_args[0].size = sizeof(struct fuse_open_in);
461 break;
462 case FUSE_MKNOD:
463 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
464 break;
465 }
466 }
467}
468
469static void fuse_force_creds(struct fuse_req *req)
470{
471 struct fuse_conn *fc = req->fm->fc;
472
473 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
474 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
475 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
476}
477
478static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
479{
480 req->in.h.opcode = args->opcode;
481 req->in.h.nodeid = args->nodeid;
482 req->args = args;
483 if (args->end)
484 __set_bit(FR_ASYNC, &req->flags);
485}
486
487ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
488{
489 struct fuse_conn *fc = fm->fc;
490 struct fuse_req *req;
491 ssize_t ret;
492
493 if (args->force) {
494 atomic_inc(&fc->num_waiting);
495 req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL);
496
497 if (!args->nocreds)
498 fuse_force_creds(req);
499
500 __set_bit(FR_WAITING, &req->flags);
501 __set_bit(FR_FORCE, &req->flags);
502 } else {
503 WARN_ON(args->nocreds);
504 req = fuse_get_req(fm, false);
505 if (IS_ERR(req))
506 return PTR_ERR(req);
507 }
508
509 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
510 fuse_adjust_compat(fc, args);
511 fuse_args_to_req(req, args);
512
513 if (!args->noreply)
514 __set_bit(FR_ISREPLY, &req->flags);
515 __fuse_request_send(req);
516 ret = req->out.h.error;
517 if (!ret && args->out_argvar) {
518 BUG_ON(args->out_numargs == 0);
519 ret = args->out_args[args->out_numargs - 1].size;
520 }
521 fuse_put_request(req);
522
523 return ret;
524}
525
526static bool fuse_request_queue_background(struct fuse_req *req)
527{
528 struct fuse_mount *fm = req->fm;
529 struct fuse_conn *fc = fm->fc;
530 bool queued = false;
531
532 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
533 if (!test_bit(FR_WAITING, &req->flags)) {
534 __set_bit(FR_WAITING, &req->flags);
535 atomic_inc(&fc->num_waiting);
536 }
537 __set_bit(FR_ISREPLY, &req->flags);
538 spin_lock(&fc->bg_lock);
539 if (likely(fc->connected)) {
540 fc->num_background++;
541 if (fc->num_background == fc->max_background)
542 fc->blocked = 1;
543 if (fc->num_background == fc->congestion_threshold && fm->sb) {
544 set_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
545 set_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC);
546 }
547 list_add_tail(&req->list, &fc->bg_queue);
548 flush_bg_queue(fc);
549 queued = true;
550 }
551 spin_unlock(&fc->bg_lock);
552
553 return queued;
554}
555
556int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
557 gfp_t gfp_flags)
558{
559 struct fuse_req *req;
560
561 if (args->force) {
562 WARN_ON(!args->nocreds);
563 req = fuse_request_alloc(fm, gfp_flags);
564 if (!req)
565 return -ENOMEM;
566 __set_bit(FR_BACKGROUND, &req->flags);
567 } else {
568 WARN_ON(args->nocreds);
569 req = fuse_get_req(fm, true);
570 if (IS_ERR(req))
571 return PTR_ERR(req);
572 }
573
574 fuse_args_to_req(req, args);
575
576 if (!fuse_request_queue_background(req)) {
577 fuse_put_request(req);
578 return -ENOTCONN;
579 }
580
581 return 0;
582}
583EXPORT_SYMBOL_GPL(fuse_simple_background);
584
585static int fuse_simple_notify_reply(struct fuse_mount *fm,
586 struct fuse_args *args, u64 unique)
587{
588 struct fuse_req *req;
589 struct fuse_iqueue *fiq = &fm->fc->iq;
590 int err = 0;
591
592 req = fuse_get_req(fm, false);
593 if (IS_ERR(req))
594 return PTR_ERR(req);
595
596 __clear_bit(FR_ISREPLY, &req->flags);
597 req->in.h.unique = unique;
598
599 fuse_args_to_req(req, args);
600
601 spin_lock(&fiq->lock);
602 if (fiq->connected) {
603 queue_request_and_unlock(fiq, req);
604 } else {
605 err = -ENODEV;
606 spin_unlock(&fiq->lock);
607 fuse_put_request(req);
608 }
609
610 return err;
611}
612
613/*
614 * Lock the request. Up to the next unlock_request() there mustn't be
615 * anything that could cause a page-fault. If the request was already
616 * aborted bail out.
617 */
618static int lock_request(struct fuse_req *req)
619{
620 int err = 0;
621 if (req) {
622 spin_lock(&req->waitq.lock);
623 if (test_bit(FR_ABORTED, &req->flags))
624 err = -ENOENT;
625 else
626 set_bit(FR_LOCKED, &req->flags);
627 spin_unlock(&req->waitq.lock);
628 }
629 return err;
630}
631
632/*
633 * Unlock request. If it was aborted while locked, caller is responsible
634 * for unlocking and ending the request.
635 */
636static int unlock_request(struct fuse_req *req)
637{
638 int err = 0;
639 if (req) {
640 spin_lock(&req->waitq.lock);
641 if (test_bit(FR_ABORTED, &req->flags))
642 err = -ENOENT;
643 else
644 clear_bit(FR_LOCKED, &req->flags);
645 spin_unlock(&req->waitq.lock);
646 }
647 return err;
648}
649
650struct fuse_copy_state {
651 int write;
652 struct fuse_req *req;
653 struct iov_iter *iter;
654 struct pipe_buffer *pipebufs;
655 struct pipe_buffer *currbuf;
656 struct pipe_inode_info *pipe;
657 unsigned long nr_segs;
658 struct page *pg;
659 unsigned len;
660 unsigned offset;
661 unsigned move_pages:1;
662};
663
664static void fuse_copy_init(struct fuse_copy_state *cs, int write,
665 struct iov_iter *iter)
666{
667 memset(cs, 0, sizeof(*cs));
668 cs->write = write;
669 cs->iter = iter;
670}
671
672/* Unmap and put previous page of userspace buffer */
673static void fuse_copy_finish(struct fuse_copy_state *cs)
674{
675 if (cs->currbuf) {
676 struct pipe_buffer *buf = cs->currbuf;
677
678 if (cs->write)
679 buf->len = PAGE_SIZE - cs->len;
680 cs->currbuf = NULL;
681 } else if (cs->pg) {
682 if (cs->write) {
683 flush_dcache_page(cs->pg);
684 set_page_dirty_lock(cs->pg);
685 }
686 put_page(cs->pg);
687 }
688 cs->pg = NULL;
689}
690
691/*
692 * Get another pagefull of userspace buffer, and map it to kernel
693 * address space, and lock request
694 */
695static int fuse_copy_fill(struct fuse_copy_state *cs)
696{
697 struct page *page;
698 int err;
699
700 err = unlock_request(cs->req);
701 if (err)
702 return err;
703
704 fuse_copy_finish(cs);
705 if (cs->pipebufs) {
706 struct pipe_buffer *buf = cs->pipebufs;
707
708 if (!cs->write) {
709 err = pipe_buf_confirm(cs->pipe, buf);
710 if (err)
711 return err;
712
713 BUG_ON(!cs->nr_segs);
714 cs->currbuf = buf;
715 cs->pg = buf->page;
716 cs->offset = buf->offset;
717 cs->len = buf->len;
718 cs->pipebufs++;
719 cs->nr_segs--;
720 } else {
721 if (cs->nr_segs >= cs->pipe->max_usage)
722 return -EIO;
723
724 page = alloc_page(GFP_HIGHUSER);
725 if (!page)
726 return -ENOMEM;
727
728 buf->page = page;
729 buf->offset = 0;
730 buf->len = 0;
731
732 cs->currbuf = buf;
733 cs->pg = page;
734 cs->offset = 0;
735 cs->len = PAGE_SIZE;
736 cs->pipebufs++;
737 cs->nr_segs++;
738 }
739 } else {
740 size_t off;
741 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
742 if (err < 0)
743 return err;
744 BUG_ON(!err);
745 cs->len = err;
746 cs->offset = off;
747 cs->pg = page;
748 iov_iter_advance(cs->iter, err);
749 }
750
751 return lock_request(cs->req);
752}
753
754/* Do as much copy to/from userspace buffer as we can */
755static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
756{
757 unsigned ncpy = min(*size, cs->len);
758 if (val) {
759 void *pgaddr = kmap_atomic(cs->pg);
760 void *buf = pgaddr + cs->offset;
761
762 if (cs->write)
763 memcpy(buf, *val, ncpy);
764 else
765 memcpy(*val, buf, ncpy);
766
767 kunmap_atomic(pgaddr);
768 *val += ncpy;
769 }
770 *size -= ncpy;
771 cs->len -= ncpy;
772 cs->offset += ncpy;
773 return ncpy;
774}
775
776static int fuse_check_page(struct page *page)
777{
778 if (page_mapcount(page) ||
779 page->mapping != NULL ||
780 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
781 ~(1 << PG_locked |
782 1 << PG_referenced |
783 1 << PG_uptodate |
784 1 << PG_lru |
785 1 << PG_active |
786 1 << PG_reclaim |
787 1 << PG_waiters))) {
788 dump_page(page, "fuse: trying to steal weird page");
789 return 1;
790 }
791 return 0;
792}
793
794static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
795{
796 int err;
797 struct page *oldpage = *pagep;
798 struct page *newpage;
799 struct pipe_buffer *buf = cs->pipebufs;
800
801 get_page(oldpage);
802 err = unlock_request(cs->req);
803 if (err)
804 goto out_put_old;
805
806 fuse_copy_finish(cs);
807
808 err = pipe_buf_confirm(cs->pipe, buf);
809 if (err)
810 goto out_put_old;
811
812 BUG_ON(!cs->nr_segs);
813 cs->currbuf = buf;
814 cs->len = buf->len;
815 cs->pipebufs++;
816 cs->nr_segs--;
817
818 if (cs->len != PAGE_SIZE)
819 goto out_fallback;
820
821 if (!pipe_buf_try_steal(cs->pipe, buf))
822 goto out_fallback;
823
824 newpage = buf->page;
825
826 if (!PageUptodate(newpage))
827 SetPageUptodate(newpage);
828
829 ClearPageMappedToDisk(newpage);
830
831 if (fuse_check_page(newpage) != 0)
832 goto out_fallback_unlock;
833
834 /*
835 * This is a new and locked page, it shouldn't be mapped or
836 * have any special flags on it
837 */
838 if (WARN_ON(page_mapped(oldpage)))
839 goto out_fallback_unlock;
840 if (WARN_ON(page_has_private(oldpage)))
841 goto out_fallback_unlock;
842 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
843 goto out_fallback_unlock;
844 if (WARN_ON(PageMlocked(oldpage)))
845 goto out_fallback_unlock;
846
847 replace_page_cache_page(oldpage, newpage);
848
849 get_page(newpage);
850
851 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
852 lru_cache_add(newpage);
853
854 err = 0;
855 spin_lock(&cs->req->waitq.lock);
856 if (test_bit(FR_ABORTED, &cs->req->flags))
857 err = -ENOENT;
858 else
859 *pagep = newpage;
860 spin_unlock(&cs->req->waitq.lock);
861
862 if (err) {
863 unlock_page(newpage);
864 put_page(newpage);
865 goto out_put_old;
866 }
867
868 unlock_page(oldpage);
869 /* Drop ref for ap->pages[] array */
870 put_page(oldpage);
871 cs->len = 0;
872
873 err = 0;
874out_put_old:
875 /* Drop ref obtained in this function */
876 put_page(oldpage);
877 return err;
878
879out_fallback_unlock:
880 unlock_page(newpage);
881out_fallback:
882 cs->pg = buf->page;
883 cs->offset = buf->offset;
884
885 err = lock_request(cs->req);
886 if (!err)
887 err = 1;
888
889 goto out_put_old;
890}
891
892static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
893 unsigned offset, unsigned count)
894{
895 struct pipe_buffer *buf;
896 int err;
897
898 if (cs->nr_segs >= cs->pipe->max_usage)
899 return -EIO;
900
901 get_page(page);
902 err = unlock_request(cs->req);
903 if (err) {
904 put_page(page);
905 return err;
906 }
907
908 fuse_copy_finish(cs);
909
910 buf = cs->pipebufs;
911 buf->page = page;
912 buf->offset = offset;
913 buf->len = count;
914
915 cs->pipebufs++;
916 cs->nr_segs++;
917 cs->len = 0;
918
919 return 0;
920}
921
922/*
923 * Copy a page in the request to/from the userspace buffer. Must be
924 * done atomically
925 */
926static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
927 unsigned offset, unsigned count, int zeroing)
928{
929 int err;
930 struct page *page = *pagep;
931
932 if (page && zeroing && count < PAGE_SIZE)
933 clear_highpage(page);
934
935 while (count) {
936 if (cs->write && cs->pipebufs && page) {
937 return fuse_ref_page(cs, page, offset, count);
938 } else if (!cs->len) {
939 if (cs->move_pages && page &&
940 offset == 0 && count == PAGE_SIZE) {
941 err = fuse_try_move_page(cs, pagep);
942 if (err <= 0)
943 return err;
944 } else {
945 err = fuse_copy_fill(cs);
946 if (err)
947 return err;
948 }
949 }
950 if (page) {
951 void *mapaddr = kmap_atomic(page);
952 void *buf = mapaddr + offset;
953 offset += fuse_copy_do(cs, &buf, &count);
954 kunmap_atomic(mapaddr);
955 } else
956 offset += fuse_copy_do(cs, NULL, &count);
957 }
958 if (page && !cs->write)
959 flush_dcache_page(page);
960 return 0;
961}
962
963/* Copy pages in the request to/from userspace buffer */
964static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
965 int zeroing)
966{
967 unsigned i;
968 struct fuse_req *req = cs->req;
969 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
970
971
972 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
973 int err;
974 unsigned int offset = ap->descs[i].offset;
975 unsigned int count = min(nbytes, ap->descs[i].length);
976
977 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
978 if (err)
979 return err;
980
981 nbytes -= count;
982 }
983 return 0;
984}
985
986/* Copy a single argument in the request to/from userspace buffer */
987static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
988{
989 while (size) {
990 if (!cs->len) {
991 int err = fuse_copy_fill(cs);
992 if (err)
993 return err;
994 }
995 fuse_copy_do(cs, &val, &size);
996 }
997 return 0;
998}
999
1000/* Copy request arguments to/from userspace buffer */
1001static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1002 unsigned argpages, struct fuse_arg *args,
1003 int zeroing)
1004{
1005 int err = 0;
1006 unsigned i;
1007
1008 for (i = 0; !err && i < numargs; i++) {
1009 struct fuse_arg *arg = &args[i];
1010 if (i == numargs - 1 && argpages)
1011 err = fuse_copy_pages(cs, arg->size, zeroing);
1012 else
1013 err = fuse_copy_one(cs, arg->value, arg->size);
1014 }
1015 return err;
1016}
1017
1018static int forget_pending(struct fuse_iqueue *fiq)
1019{
1020 return fiq->forget_list_head.next != NULL;
1021}
1022
1023static int request_pending(struct fuse_iqueue *fiq)
1024{
1025 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1026 forget_pending(fiq);
1027}
1028
1029/*
1030 * Transfer an interrupt request to userspace
1031 *
1032 * Unlike other requests this is assembled on demand, without a need
1033 * to allocate a separate fuse_req structure.
1034 *
1035 * Called with fiq->lock held, releases it
1036 */
1037static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1038 struct fuse_copy_state *cs,
1039 size_t nbytes, struct fuse_req *req)
1040__releases(fiq->lock)
1041{
1042 struct fuse_in_header ih;
1043 struct fuse_interrupt_in arg;
1044 unsigned reqsize = sizeof(ih) + sizeof(arg);
1045 int err;
1046
1047 list_del_init(&req->intr_entry);
1048 memset(&ih, 0, sizeof(ih));
1049 memset(&arg, 0, sizeof(arg));
1050 ih.len = reqsize;
1051 ih.opcode = FUSE_INTERRUPT;
1052 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1053 arg.unique = req->in.h.unique;
1054
1055 spin_unlock(&fiq->lock);
1056 if (nbytes < reqsize)
1057 return -EINVAL;
1058
1059 err = fuse_copy_one(cs, &ih, sizeof(ih));
1060 if (!err)
1061 err = fuse_copy_one(cs, &arg, sizeof(arg));
1062 fuse_copy_finish(cs);
1063
1064 return err ? err : reqsize;
1065}
1066
1067struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1068 unsigned int max,
1069 unsigned int *countp)
1070{
1071 struct fuse_forget_link *head = fiq->forget_list_head.next;
1072 struct fuse_forget_link **newhead = &head;
1073 unsigned count;
1074
1075 for (count = 0; *newhead != NULL && count < max; count++)
1076 newhead = &(*newhead)->next;
1077
1078 fiq->forget_list_head.next = *newhead;
1079 *newhead = NULL;
1080 if (fiq->forget_list_head.next == NULL)
1081 fiq->forget_list_tail = &fiq->forget_list_head;
1082
1083 if (countp != NULL)
1084 *countp = count;
1085
1086 return head;
1087}
1088EXPORT_SYMBOL(fuse_dequeue_forget);
1089
1090static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1091 struct fuse_copy_state *cs,
1092 size_t nbytes)
1093__releases(fiq->lock)
1094{
1095 int err;
1096 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1097 struct fuse_forget_in arg = {
1098 .nlookup = forget->forget_one.nlookup,
1099 };
1100 struct fuse_in_header ih = {
1101 .opcode = FUSE_FORGET,
1102 .nodeid = forget->forget_one.nodeid,
1103 .unique = fuse_get_unique(fiq),
1104 .len = sizeof(ih) + sizeof(arg),
1105 };
1106
1107 spin_unlock(&fiq->lock);
1108 kfree(forget);
1109 if (nbytes < ih.len)
1110 return -EINVAL;
1111
1112 err = fuse_copy_one(cs, &ih, sizeof(ih));
1113 if (!err)
1114 err = fuse_copy_one(cs, &arg, sizeof(arg));
1115 fuse_copy_finish(cs);
1116
1117 if (err)
1118 return err;
1119
1120 return ih.len;
1121}
1122
1123static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1124 struct fuse_copy_state *cs, size_t nbytes)
1125__releases(fiq->lock)
1126{
1127 int err;
1128 unsigned max_forgets;
1129 unsigned count;
1130 struct fuse_forget_link *head;
1131 struct fuse_batch_forget_in arg = { .count = 0 };
1132 struct fuse_in_header ih = {
1133 .opcode = FUSE_BATCH_FORGET,
1134 .unique = fuse_get_unique(fiq),
1135 .len = sizeof(ih) + sizeof(arg),
1136 };
1137
1138 if (nbytes < ih.len) {
1139 spin_unlock(&fiq->lock);
1140 return -EINVAL;
1141 }
1142
1143 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1144 head = fuse_dequeue_forget(fiq, max_forgets, &count);
1145 spin_unlock(&fiq->lock);
1146
1147 arg.count = count;
1148 ih.len += count * sizeof(struct fuse_forget_one);
1149 err = fuse_copy_one(cs, &ih, sizeof(ih));
1150 if (!err)
1151 err = fuse_copy_one(cs, &arg, sizeof(arg));
1152
1153 while (head) {
1154 struct fuse_forget_link *forget = head;
1155
1156 if (!err) {
1157 err = fuse_copy_one(cs, &forget->forget_one,
1158 sizeof(forget->forget_one));
1159 }
1160 head = forget->next;
1161 kfree(forget);
1162 }
1163
1164 fuse_copy_finish(cs);
1165
1166 if (err)
1167 return err;
1168
1169 return ih.len;
1170}
1171
1172static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1173 struct fuse_copy_state *cs,
1174 size_t nbytes)
1175__releases(fiq->lock)
1176{
1177 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1178 return fuse_read_single_forget(fiq, cs, nbytes);
1179 else
1180 return fuse_read_batch_forget(fiq, cs, nbytes);
1181}
1182
1183/*
1184 * Read a single request into the userspace filesystem's buffer. This
1185 * function waits until a request is available, then removes it from
1186 * the pending list and copies request data to userspace buffer. If
1187 * no reply is needed (FORGET) or request has been aborted or there
1188 * was an error during the copying then it's finished by calling
1189 * fuse_request_end(). Otherwise add it to the processing list, and set
1190 * the 'sent' flag.
1191 */
1192static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1193 struct fuse_copy_state *cs, size_t nbytes)
1194{
1195 ssize_t err;
1196 struct fuse_conn *fc = fud->fc;
1197 struct fuse_iqueue *fiq = &fc->iq;
1198 struct fuse_pqueue *fpq = &fud->pq;
1199 struct fuse_req *req;
1200 struct fuse_args *args;
1201 unsigned reqsize;
1202 unsigned int hash;
1203
1204 /*
1205 * Require sane minimum read buffer - that has capacity for fixed part
1206 * of any request header + negotiated max_write room for data.
1207 *
1208 * Historically libfuse reserves 4K for fixed header room, but e.g.
1209 * GlusterFS reserves only 80 bytes
1210 *
1211 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1212 *
1213 * which is the absolute minimum any sane filesystem should be using
1214 * for header room.
1215 */
1216 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1217 sizeof(struct fuse_in_header) +
1218 sizeof(struct fuse_write_in) +
1219 fc->max_write))
1220 return -EINVAL;
1221
1222 restart:
1223 for (;;) {
1224 spin_lock(&fiq->lock);
1225 if (!fiq->connected || request_pending(fiq))
1226 break;
1227 spin_unlock(&fiq->lock);
1228
1229 if (file->f_flags & O_NONBLOCK)
1230 return -EAGAIN;
1231 err = wait_event_interruptible_exclusive(fiq->waitq,
1232 !fiq->connected || request_pending(fiq));
1233 if (err)
1234 return err;
1235 }
1236
1237 if (!fiq->connected) {
1238 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1239 goto err_unlock;
1240 }
1241
1242 if (!list_empty(&fiq->interrupts)) {
1243 req = list_entry(fiq->interrupts.next, struct fuse_req,
1244 intr_entry);
1245 return fuse_read_interrupt(fiq, cs, nbytes, req);
1246 }
1247
1248 if (forget_pending(fiq)) {
1249 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1250 return fuse_read_forget(fc, fiq, cs, nbytes);
1251
1252 if (fiq->forget_batch <= -8)
1253 fiq->forget_batch = 16;
1254 }
1255
1256 req = list_entry(fiq->pending.next, struct fuse_req, list);
1257 clear_bit(FR_PENDING, &req->flags);
1258 list_del_init(&req->list);
1259 spin_unlock(&fiq->lock);
1260
1261 args = req->args;
1262 reqsize = req->in.h.len;
1263
1264 /* If request is too large, reply with an error and restart the read */
1265 if (nbytes < reqsize) {
1266 req->out.h.error = -EIO;
1267 /* SETXATTR is special, since it may contain too large data */
1268 if (args->opcode == FUSE_SETXATTR)
1269 req->out.h.error = -E2BIG;
1270 fuse_request_end(req);
1271 goto restart;
1272 }
1273 spin_lock(&fpq->lock);
1274 list_add(&req->list, &fpq->io);
1275 spin_unlock(&fpq->lock);
1276 cs->req = req;
1277 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1278 if (!err)
1279 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1280 (struct fuse_arg *) args->in_args, 0);
1281 fuse_copy_finish(cs);
1282 spin_lock(&fpq->lock);
1283 clear_bit(FR_LOCKED, &req->flags);
1284 if (!fpq->connected) {
1285 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1286 goto out_end;
1287 }
1288 if (err) {
1289 req->out.h.error = -EIO;
1290 goto out_end;
1291 }
1292 if (!test_bit(FR_ISREPLY, &req->flags)) {
1293 err = reqsize;
1294 goto out_end;
1295 }
1296 hash = fuse_req_hash(req->in.h.unique);
1297 list_move_tail(&req->list, &fpq->processing[hash]);
1298 __fuse_get_request(req);
1299 set_bit(FR_SENT, &req->flags);
1300 spin_unlock(&fpq->lock);
1301 /* matches barrier in request_wait_answer() */
1302 smp_mb__after_atomic();
1303 if (test_bit(FR_INTERRUPTED, &req->flags))
1304 queue_interrupt(req);
1305 fuse_put_request(req);
1306
1307 return reqsize;
1308
1309out_end:
1310 if (!test_bit(FR_PRIVATE, &req->flags))
1311 list_del_init(&req->list);
1312 spin_unlock(&fpq->lock);
1313 fuse_request_end(req);
1314 return err;
1315
1316 err_unlock:
1317 spin_unlock(&fiq->lock);
1318 return err;
1319}
1320
1321static int fuse_dev_open(struct inode *inode, struct file *file)
1322{
1323 /*
1324 * The fuse device's file's private_data is used to hold
1325 * the fuse_conn(ection) when it is mounted, and is used to
1326 * keep track of whether the file has been mounted already.
1327 */
1328 file->private_data = NULL;
1329 return 0;
1330}
1331
1332static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1333{
1334 struct fuse_copy_state cs;
1335 struct file *file = iocb->ki_filp;
1336 struct fuse_dev *fud = fuse_get_dev(file);
1337
1338 if (!fud)
1339 return -EPERM;
1340
1341 if (!iter_is_iovec(to))
1342 return -EINVAL;
1343
1344 fuse_copy_init(&cs, 1, to);
1345
1346 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1347}
1348
1349static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1350 struct pipe_inode_info *pipe,
1351 size_t len, unsigned int flags)
1352{
1353 int total, ret;
1354 int page_nr = 0;
1355 struct pipe_buffer *bufs;
1356 struct fuse_copy_state cs;
1357 struct fuse_dev *fud = fuse_get_dev(in);
1358
1359 if (!fud)
1360 return -EPERM;
1361
1362 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1363 GFP_KERNEL);
1364 if (!bufs)
1365 return -ENOMEM;
1366
1367 fuse_copy_init(&cs, 1, NULL);
1368 cs.pipebufs = bufs;
1369 cs.pipe = pipe;
1370 ret = fuse_dev_do_read(fud, in, &cs, len);
1371 if (ret < 0)
1372 goto out;
1373
1374 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1375 ret = -EIO;
1376 goto out;
1377 }
1378
1379 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1380 /*
1381 * Need to be careful about this. Having buf->ops in module
1382 * code can Oops if the buffer persists after module unload.
1383 */
1384 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1385 bufs[page_nr].flags = 0;
1386 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1387 if (unlikely(ret < 0))
1388 break;
1389 }
1390 if (total)
1391 ret = total;
1392out:
1393 for (; page_nr < cs.nr_segs; page_nr++)
1394 put_page(bufs[page_nr].page);
1395
1396 kvfree(bufs);
1397 return ret;
1398}
1399
1400static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1401 struct fuse_copy_state *cs)
1402{
1403 struct fuse_notify_poll_wakeup_out outarg;
1404 int err = -EINVAL;
1405
1406 if (size != sizeof(outarg))
1407 goto err;
1408
1409 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1410 if (err)
1411 goto err;
1412
1413 fuse_copy_finish(cs);
1414 return fuse_notify_poll_wakeup(fc, &outarg);
1415
1416err:
1417 fuse_copy_finish(cs);
1418 return err;
1419}
1420
1421static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1422 struct fuse_copy_state *cs)
1423{
1424 struct fuse_notify_inval_inode_out outarg;
1425 int err = -EINVAL;
1426
1427 if (size != sizeof(outarg))
1428 goto err;
1429
1430 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1431 if (err)
1432 goto err;
1433 fuse_copy_finish(cs);
1434
1435 down_read(&fc->killsb);
1436 err = fuse_reverse_inval_inode(fc, outarg.ino,
1437 outarg.off, outarg.len);
1438 up_read(&fc->killsb);
1439 return err;
1440
1441err:
1442 fuse_copy_finish(cs);
1443 return err;
1444}
1445
1446static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1447 struct fuse_copy_state *cs)
1448{
1449 struct fuse_notify_inval_entry_out outarg;
1450 int err = -ENOMEM;
1451 char *buf;
1452 struct qstr name;
1453
1454 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1455 if (!buf)
1456 goto err;
1457
1458 err = -EINVAL;
1459 if (size < sizeof(outarg))
1460 goto err;
1461
1462 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1463 if (err)
1464 goto err;
1465
1466 err = -ENAMETOOLONG;
1467 if (outarg.namelen > FUSE_NAME_MAX)
1468 goto err;
1469
1470 err = -EINVAL;
1471 if (size != sizeof(outarg) + outarg.namelen + 1)
1472 goto err;
1473
1474 name.name = buf;
1475 name.len = outarg.namelen;
1476 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1477 if (err)
1478 goto err;
1479 fuse_copy_finish(cs);
1480 buf[outarg.namelen] = 0;
1481
1482 down_read(&fc->killsb);
1483 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name);
1484 up_read(&fc->killsb);
1485 kfree(buf);
1486 return err;
1487
1488err:
1489 kfree(buf);
1490 fuse_copy_finish(cs);
1491 return err;
1492}
1493
1494static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1495 struct fuse_copy_state *cs)
1496{
1497 struct fuse_notify_delete_out outarg;
1498 int err = -ENOMEM;
1499 char *buf;
1500 struct qstr name;
1501
1502 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1503 if (!buf)
1504 goto err;
1505
1506 err = -EINVAL;
1507 if (size < sizeof(outarg))
1508 goto err;
1509
1510 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1511 if (err)
1512 goto err;
1513
1514 err = -ENAMETOOLONG;
1515 if (outarg.namelen > FUSE_NAME_MAX)
1516 goto err;
1517
1518 err = -EINVAL;
1519 if (size != sizeof(outarg) + outarg.namelen + 1)
1520 goto err;
1521
1522 name.name = buf;
1523 name.len = outarg.namelen;
1524 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1525 if (err)
1526 goto err;
1527 fuse_copy_finish(cs);
1528 buf[outarg.namelen] = 0;
1529
1530 down_read(&fc->killsb);
1531 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name);
1532 up_read(&fc->killsb);
1533 kfree(buf);
1534 return err;
1535
1536err:
1537 kfree(buf);
1538 fuse_copy_finish(cs);
1539 return err;
1540}
1541
1542static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1543 struct fuse_copy_state *cs)
1544{
1545 struct fuse_notify_store_out outarg;
1546 struct inode *inode;
1547 struct address_space *mapping;
1548 u64 nodeid;
1549 int err;
1550 pgoff_t index;
1551 unsigned int offset;
1552 unsigned int num;
1553 loff_t file_size;
1554 loff_t end;
1555
1556 err = -EINVAL;
1557 if (size < sizeof(outarg))
1558 goto out_finish;
1559
1560 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1561 if (err)
1562 goto out_finish;
1563
1564 err = -EINVAL;
1565 if (size - sizeof(outarg) != outarg.size)
1566 goto out_finish;
1567
1568 nodeid = outarg.nodeid;
1569
1570 down_read(&fc->killsb);
1571
1572 err = -ENOENT;
1573 inode = fuse_ilookup(fc, nodeid, NULL);
1574 if (!inode)
1575 goto out_up_killsb;
1576
1577 mapping = inode->i_mapping;
1578 index = outarg.offset >> PAGE_SHIFT;
1579 offset = outarg.offset & ~PAGE_MASK;
1580 file_size = i_size_read(inode);
1581 end = outarg.offset + outarg.size;
1582 if (end > file_size) {
1583 file_size = end;
1584 fuse_write_update_size(inode, file_size);
1585 }
1586
1587 num = outarg.size;
1588 while (num) {
1589 struct page *page;
1590 unsigned int this_num;
1591
1592 err = -ENOMEM;
1593 page = find_or_create_page(mapping, index,
1594 mapping_gfp_mask(mapping));
1595 if (!page)
1596 goto out_iput;
1597
1598 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1599 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1600 if (!err && offset == 0 &&
1601 (this_num == PAGE_SIZE || file_size == end))
1602 SetPageUptodate(page);
1603 unlock_page(page);
1604 put_page(page);
1605
1606 if (err)
1607 goto out_iput;
1608
1609 num -= this_num;
1610 offset = 0;
1611 index++;
1612 }
1613
1614 err = 0;
1615
1616out_iput:
1617 iput(inode);
1618out_up_killsb:
1619 up_read(&fc->killsb);
1620out_finish:
1621 fuse_copy_finish(cs);
1622 return err;
1623}
1624
1625struct fuse_retrieve_args {
1626 struct fuse_args_pages ap;
1627 struct fuse_notify_retrieve_in inarg;
1628};
1629
1630static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1631 int error)
1632{
1633 struct fuse_retrieve_args *ra =
1634 container_of(args, typeof(*ra), ap.args);
1635
1636 release_pages(ra->ap.pages, ra->ap.num_pages);
1637 kfree(ra);
1638}
1639
1640static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1641 struct fuse_notify_retrieve_out *outarg)
1642{
1643 int err;
1644 struct address_space *mapping = inode->i_mapping;
1645 pgoff_t index;
1646 loff_t file_size;
1647 unsigned int num;
1648 unsigned int offset;
1649 size_t total_len = 0;
1650 unsigned int num_pages;
1651 struct fuse_conn *fc = fm->fc;
1652 struct fuse_retrieve_args *ra;
1653 size_t args_size = sizeof(*ra);
1654 struct fuse_args_pages *ap;
1655 struct fuse_args *args;
1656
1657 offset = outarg->offset & ~PAGE_MASK;
1658 file_size = i_size_read(inode);
1659
1660 num = min(outarg->size, fc->max_write);
1661 if (outarg->offset > file_size)
1662 num = 0;
1663 else if (outarg->offset + num > file_size)
1664 num = file_size - outarg->offset;
1665
1666 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1667 num_pages = min(num_pages, fc->max_pages);
1668
1669 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1670
1671 ra = kzalloc(args_size, GFP_KERNEL);
1672 if (!ra)
1673 return -ENOMEM;
1674
1675 ap = &ra->ap;
1676 ap->pages = (void *) (ra + 1);
1677 ap->descs = (void *) (ap->pages + num_pages);
1678
1679 args = &ap->args;
1680 args->nodeid = outarg->nodeid;
1681 args->opcode = FUSE_NOTIFY_REPLY;
1682 args->in_numargs = 2;
1683 args->in_pages = true;
1684 args->end = fuse_retrieve_end;
1685
1686 index = outarg->offset >> PAGE_SHIFT;
1687
1688 while (num && ap->num_pages < num_pages) {
1689 struct page *page;
1690 unsigned int this_num;
1691
1692 page = find_get_page(mapping, index);
1693 if (!page)
1694 break;
1695
1696 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1697 ap->pages[ap->num_pages] = page;
1698 ap->descs[ap->num_pages].offset = offset;
1699 ap->descs[ap->num_pages].length = this_num;
1700 ap->num_pages++;
1701
1702 offset = 0;
1703 num -= this_num;
1704 total_len += this_num;
1705 index++;
1706 }
1707 ra->inarg.offset = outarg->offset;
1708 ra->inarg.size = total_len;
1709 args->in_args[0].size = sizeof(ra->inarg);
1710 args->in_args[0].value = &ra->inarg;
1711 args->in_args[1].size = total_len;
1712
1713 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1714 if (err)
1715 fuse_retrieve_end(fm, args, err);
1716
1717 return err;
1718}
1719
1720static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1721 struct fuse_copy_state *cs)
1722{
1723 struct fuse_notify_retrieve_out outarg;
1724 struct fuse_mount *fm;
1725 struct inode *inode;
1726 u64 nodeid;
1727 int err;
1728
1729 err = -EINVAL;
1730 if (size != sizeof(outarg))
1731 goto copy_finish;
1732
1733 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1734 if (err)
1735 goto copy_finish;
1736
1737 fuse_copy_finish(cs);
1738
1739 down_read(&fc->killsb);
1740 err = -ENOENT;
1741 nodeid = outarg.nodeid;
1742
1743 inode = fuse_ilookup(fc, nodeid, &fm);
1744 if (inode) {
1745 err = fuse_retrieve(fm, inode, &outarg);
1746 iput(inode);
1747 }
1748 up_read(&fc->killsb);
1749
1750 return err;
1751
1752copy_finish:
1753 fuse_copy_finish(cs);
1754 return err;
1755}
1756
1757static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1758 unsigned int size, struct fuse_copy_state *cs)
1759{
1760 /* Don't try to move pages (yet) */
1761 cs->move_pages = 0;
1762
1763 switch (code) {
1764 case FUSE_NOTIFY_POLL:
1765 return fuse_notify_poll(fc, size, cs);
1766
1767 case FUSE_NOTIFY_INVAL_INODE:
1768 return fuse_notify_inval_inode(fc, size, cs);
1769
1770 case FUSE_NOTIFY_INVAL_ENTRY:
1771 return fuse_notify_inval_entry(fc, size, cs);
1772
1773 case FUSE_NOTIFY_STORE:
1774 return fuse_notify_store(fc, size, cs);
1775
1776 case FUSE_NOTIFY_RETRIEVE:
1777 return fuse_notify_retrieve(fc, size, cs);
1778
1779 case FUSE_NOTIFY_DELETE:
1780 return fuse_notify_delete(fc, size, cs);
1781
1782 default:
1783 fuse_copy_finish(cs);
1784 return -EINVAL;
1785 }
1786}
1787
1788/* Look up request on processing list by unique ID */
1789static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1790{
1791 unsigned int hash = fuse_req_hash(unique);
1792 struct fuse_req *req;
1793
1794 list_for_each_entry(req, &fpq->processing[hash], list) {
1795 if (req->in.h.unique == unique)
1796 return req;
1797 }
1798 return NULL;
1799}
1800
1801static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1802 unsigned nbytes)
1803{
1804 unsigned reqsize = sizeof(struct fuse_out_header);
1805
1806 reqsize += fuse_len_args(args->out_numargs, args->out_args);
1807
1808 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1809 return -EINVAL;
1810 else if (reqsize > nbytes) {
1811 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1812 unsigned diffsize = reqsize - nbytes;
1813
1814 if (diffsize > lastarg->size)
1815 return -EINVAL;
1816 lastarg->size -= diffsize;
1817 }
1818 return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1819 args->out_args, args->page_zeroing);
1820}
1821
1822/*
1823 * Write a single reply to a request. First the header is copied from
1824 * the write buffer. The request is then searched on the processing
1825 * list by the unique ID found in the header. If found, then remove
1826 * it from the list and copy the rest of the buffer to the request.
1827 * The request is finished by calling fuse_request_end().
1828 */
1829static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1830 struct fuse_copy_state *cs, size_t nbytes)
1831{
1832 int err;
1833 struct fuse_conn *fc = fud->fc;
1834 struct fuse_pqueue *fpq = &fud->pq;
1835 struct fuse_req *req;
1836 struct fuse_out_header oh;
1837
1838 err = -EINVAL;
1839 if (nbytes < sizeof(struct fuse_out_header))
1840 goto out;
1841
1842 err = fuse_copy_one(cs, &oh, sizeof(oh));
1843 if (err)
1844 goto copy_finish;
1845
1846 err = -EINVAL;
1847 if (oh.len != nbytes)
1848 goto copy_finish;
1849
1850 /*
1851 * Zero oh.unique indicates unsolicited notification message
1852 * and error contains notification code.
1853 */
1854 if (!oh.unique) {
1855 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1856 goto out;
1857 }
1858
1859 err = -EINVAL;
1860 if (oh.error <= -1000 || oh.error > 0)
1861 goto copy_finish;
1862
1863 spin_lock(&fpq->lock);
1864 req = NULL;
1865 if (fpq->connected)
1866 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1867
1868 err = -ENOENT;
1869 if (!req) {
1870 spin_unlock(&fpq->lock);
1871 goto copy_finish;
1872 }
1873
1874 /* Is it an interrupt reply ID? */
1875 if (oh.unique & FUSE_INT_REQ_BIT) {
1876 __fuse_get_request(req);
1877 spin_unlock(&fpq->lock);
1878
1879 err = 0;
1880 if (nbytes != sizeof(struct fuse_out_header))
1881 err = -EINVAL;
1882 else if (oh.error == -ENOSYS)
1883 fc->no_interrupt = 1;
1884 else if (oh.error == -EAGAIN)
1885 err = queue_interrupt(req);
1886
1887 fuse_put_request(req);
1888
1889 goto copy_finish;
1890 }
1891
1892 clear_bit(FR_SENT, &req->flags);
1893 list_move(&req->list, &fpq->io);
1894 req->out.h = oh;
1895 set_bit(FR_LOCKED, &req->flags);
1896 spin_unlock(&fpq->lock);
1897 cs->req = req;
1898 if (!req->args->page_replace)
1899 cs->move_pages = 0;
1900
1901 if (oh.error)
1902 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1903 else
1904 err = copy_out_args(cs, req->args, nbytes);
1905 fuse_copy_finish(cs);
1906
1907 spin_lock(&fpq->lock);
1908 clear_bit(FR_LOCKED, &req->flags);
1909 if (!fpq->connected)
1910 err = -ENOENT;
1911 else if (err)
1912 req->out.h.error = -EIO;
1913 if (!test_bit(FR_PRIVATE, &req->flags))
1914 list_del_init(&req->list);
1915 spin_unlock(&fpq->lock);
1916
1917 fuse_request_end(req);
1918out:
1919 return err ? err : nbytes;
1920
1921copy_finish:
1922 fuse_copy_finish(cs);
1923 goto out;
1924}
1925
1926static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1927{
1928 struct fuse_copy_state cs;
1929 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1930
1931 if (!fud)
1932 return -EPERM;
1933
1934 if (!iter_is_iovec(from))
1935 return -EINVAL;
1936
1937 fuse_copy_init(&cs, 0, from);
1938
1939 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1940}
1941
1942static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1943 struct file *out, loff_t *ppos,
1944 size_t len, unsigned int flags)
1945{
1946 unsigned int head, tail, mask, count;
1947 unsigned nbuf;
1948 unsigned idx;
1949 struct pipe_buffer *bufs;
1950 struct fuse_copy_state cs;
1951 struct fuse_dev *fud;
1952 size_t rem;
1953 ssize_t ret;
1954
1955 fud = fuse_get_dev(out);
1956 if (!fud)
1957 return -EPERM;
1958
1959 pipe_lock(pipe);
1960
1961 head = pipe->head;
1962 tail = pipe->tail;
1963 mask = pipe->ring_size - 1;
1964 count = head - tail;
1965
1966 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1967 if (!bufs) {
1968 pipe_unlock(pipe);
1969 return -ENOMEM;
1970 }
1971
1972 nbuf = 0;
1973 rem = 0;
1974 for (idx = tail; idx != head && rem < len; idx++)
1975 rem += pipe->bufs[idx & mask].len;
1976
1977 ret = -EINVAL;
1978 if (rem < len)
1979 goto out_free;
1980
1981 rem = len;
1982 while (rem) {
1983 struct pipe_buffer *ibuf;
1984 struct pipe_buffer *obuf;
1985
1986 if (WARN_ON(nbuf >= count || tail == head))
1987 goto out_free;
1988
1989 ibuf = &pipe->bufs[tail & mask];
1990 obuf = &bufs[nbuf];
1991
1992 if (rem >= ibuf->len) {
1993 *obuf = *ibuf;
1994 ibuf->ops = NULL;
1995 tail++;
1996 pipe->tail = tail;
1997 } else {
1998 if (!pipe_buf_get(pipe, ibuf))
1999 goto out_free;
2000
2001 *obuf = *ibuf;
2002 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2003 obuf->len = rem;
2004 ibuf->offset += obuf->len;
2005 ibuf->len -= obuf->len;
2006 }
2007 nbuf++;
2008 rem -= obuf->len;
2009 }
2010 pipe_unlock(pipe);
2011
2012 fuse_copy_init(&cs, 0, NULL);
2013 cs.pipebufs = bufs;
2014 cs.nr_segs = nbuf;
2015 cs.pipe = pipe;
2016
2017 if (flags & SPLICE_F_MOVE)
2018 cs.move_pages = 1;
2019
2020 ret = fuse_dev_do_write(fud, &cs, len);
2021
2022 pipe_lock(pipe);
2023out_free:
2024 for (idx = 0; idx < nbuf; idx++)
2025 pipe_buf_release(pipe, &bufs[idx]);
2026 pipe_unlock(pipe);
2027
2028 kvfree(bufs);
2029 return ret;
2030}
2031
2032static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2033{
2034 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2035 struct fuse_iqueue *fiq;
2036 struct fuse_dev *fud = fuse_get_dev(file);
2037
2038 if (!fud)
2039 return EPOLLERR;
2040
2041 fiq = &fud->fc->iq;
2042 poll_wait(file, &fiq->waitq, wait);
2043
2044 spin_lock(&fiq->lock);
2045 if (!fiq->connected)
2046 mask = EPOLLERR;
2047 else if (request_pending(fiq))
2048 mask |= EPOLLIN | EPOLLRDNORM;
2049 spin_unlock(&fiq->lock);
2050
2051 return mask;
2052}
2053
2054/* Abort all requests on the given list (pending or processing) */
2055static void end_requests(struct list_head *head)
2056{
2057 while (!list_empty(head)) {
2058 struct fuse_req *req;
2059 req = list_entry(head->next, struct fuse_req, list);
2060 req->out.h.error = -ECONNABORTED;
2061 clear_bit(FR_SENT, &req->flags);
2062 list_del_init(&req->list);
2063 fuse_request_end(req);
2064 }
2065}
2066
2067static void end_polls(struct fuse_conn *fc)
2068{
2069 struct rb_node *p;
2070
2071 p = rb_first(&fc->polled_files);
2072
2073 while (p) {
2074 struct fuse_file *ff;
2075 ff = rb_entry(p, struct fuse_file, polled_node);
2076 wake_up_interruptible_all(&ff->poll_wait);
2077
2078 p = rb_next(p);
2079 }
2080}
2081
2082/*
2083 * Abort all requests.
2084 *
2085 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2086 * filesystem.
2087 *
2088 * The same effect is usually achievable through killing the filesystem daemon
2089 * and all users of the filesystem. The exception is the combination of an
2090 * asynchronous request and the tricky deadlock (see
2091 * Documentation/filesystems/fuse.rst).
2092 *
2093 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2094 * requests, they should be finished off immediately. Locked requests will be
2095 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2096 * requests. It is possible that some request will finish before we can. This
2097 * is OK, the request will in that case be removed from the list before we touch
2098 * it.
2099 */
2100void fuse_abort_conn(struct fuse_conn *fc)
2101{
2102 struct fuse_iqueue *fiq = &fc->iq;
2103
2104 spin_lock(&fc->lock);
2105 if (fc->connected) {
2106 struct fuse_dev *fud;
2107 struct fuse_req *req, *next;
2108 LIST_HEAD(to_end);
2109 unsigned int i;
2110
2111 /* Background queuing checks fc->connected under bg_lock */
2112 spin_lock(&fc->bg_lock);
2113 fc->connected = 0;
2114 spin_unlock(&fc->bg_lock);
2115
2116 fuse_set_initialized(fc);
2117 list_for_each_entry(fud, &fc->devices, entry) {
2118 struct fuse_pqueue *fpq = &fud->pq;
2119
2120 spin_lock(&fpq->lock);
2121 fpq->connected = 0;
2122 list_for_each_entry_safe(req, next, &fpq->io, list) {
2123 req->out.h.error = -ECONNABORTED;
2124 spin_lock(&req->waitq.lock);
2125 set_bit(FR_ABORTED, &req->flags);
2126 if (!test_bit(FR_LOCKED, &req->flags)) {
2127 set_bit(FR_PRIVATE, &req->flags);
2128 __fuse_get_request(req);
2129 list_move(&req->list, &to_end);
2130 }
2131 spin_unlock(&req->waitq.lock);
2132 }
2133 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2134 list_splice_tail_init(&fpq->processing[i],
2135 &to_end);
2136 spin_unlock(&fpq->lock);
2137 }
2138 spin_lock(&fc->bg_lock);
2139 fc->blocked = 0;
2140 fc->max_background = UINT_MAX;
2141 flush_bg_queue(fc);
2142 spin_unlock(&fc->bg_lock);
2143
2144 spin_lock(&fiq->lock);
2145 fiq->connected = 0;
2146 list_for_each_entry(req, &fiq->pending, list)
2147 clear_bit(FR_PENDING, &req->flags);
2148 list_splice_tail_init(&fiq->pending, &to_end);
2149 while (forget_pending(fiq))
2150 kfree(fuse_dequeue_forget(fiq, 1, NULL));
2151 wake_up_all(&fiq->waitq);
2152 spin_unlock(&fiq->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 end_requests(&to_end);
2159 } else {
2160 spin_unlock(&fc->lock);
2161 }
2162}
2163EXPORT_SYMBOL_GPL(fuse_abort_conn);
2164
2165void fuse_wait_aborted(struct fuse_conn *fc)
2166{
2167 /* matches implicit memory barrier in fuse_drop_waiting() */
2168 smp_mb();
2169 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2170}
2171
2172int fuse_dev_release(struct inode *inode, struct file *file)
2173{
2174 struct fuse_dev *fud = fuse_get_dev(file);
2175
2176 if (fud) {
2177 struct fuse_conn *fc = fud->fc;
2178 struct fuse_pqueue *fpq = &fud->pq;
2179 LIST_HEAD(to_end);
2180 unsigned int i;
2181
2182 spin_lock(&fpq->lock);
2183 WARN_ON(!list_empty(&fpq->io));
2184 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2185 list_splice_init(&fpq->processing[i], &to_end);
2186 spin_unlock(&fpq->lock);
2187
2188 end_requests(&to_end);
2189
2190 /* Are we the last open device? */
2191 if (atomic_dec_and_test(&fc->dev_count)) {
2192 WARN_ON(fc->iq.fasync != NULL);
2193 fuse_abort_conn(fc);
2194 }
2195 fuse_dev_free(fud);
2196 }
2197 return 0;
2198}
2199EXPORT_SYMBOL_GPL(fuse_dev_release);
2200
2201static int fuse_dev_fasync(int fd, struct file *file, int on)
2202{
2203 struct fuse_dev *fud = fuse_get_dev(file);
2204
2205 if (!fud)
2206 return -EPERM;
2207
2208 /* No locking - fasync_helper does its own locking */
2209 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2210}
2211
2212static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2213{
2214 struct fuse_dev *fud;
2215
2216 if (new->private_data)
2217 return -EINVAL;
2218
2219 fud = fuse_dev_alloc_install(fc);
2220 if (!fud)
2221 return -ENOMEM;
2222
2223 new->private_data = fud;
2224 atomic_inc(&fc->dev_count);
2225
2226 return 0;
2227}
2228
2229static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2230 unsigned long arg)
2231{
2232 int res;
2233 int oldfd;
2234 struct fuse_dev *fud = NULL;
2235
2236 switch (cmd) {
2237 case FUSE_DEV_IOC_CLONE:
2238 res = -EFAULT;
2239 if (!get_user(oldfd, (__u32 __user *)arg)) {
2240 struct file *old = fget(oldfd);
2241
2242 res = -EINVAL;
2243 if (old) {
2244 /*
2245 * Check against file->f_op because CUSE
2246 * uses the same ioctl handler.
2247 */
2248 if (old->f_op == file->f_op &&
2249 old->f_cred->user_ns == file->f_cred->user_ns)
2250 fud = fuse_get_dev(old);
2251
2252 if (fud) {
2253 mutex_lock(&fuse_mutex);
2254 res = fuse_device_clone(fud->fc, file);
2255 mutex_unlock(&fuse_mutex);
2256 }
2257 fput(old);
2258 }
2259 }
2260 break;
2261 default:
2262 res = -ENOTTY;
2263 break;
2264 }
2265 return res;
2266}
2267
2268const struct file_operations fuse_dev_operations = {
2269 .owner = THIS_MODULE,
2270 .open = fuse_dev_open,
2271 .llseek = no_llseek,
2272 .read_iter = fuse_dev_read,
2273 .splice_read = fuse_dev_splice_read,
2274 .write_iter = fuse_dev_write,
2275 .splice_write = fuse_dev_splice_write,
2276 .poll = fuse_dev_poll,
2277 .release = fuse_dev_release,
2278 .fasync = fuse_dev_fasync,
2279 .unlocked_ioctl = fuse_dev_ioctl,
2280 .compat_ioctl = compat_ptr_ioctl,
2281};
2282EXPORT_SYMBOL_GPL(fuse_dev_operations);
2283
2284static struct miscdevice fuse_miscdevice = {
2285 .minor = FUSE_MINOR,
2286 .name = "fuse",
2287 .fops = &fuse_dev_operations,
2288};
2289
2290int __init fuse_dev_init(void)
2291{
2292 int err = -ENOMEM;
2293 fuse_req_cachep = kmem_cache_create("fuse_request",
2294 sizeof(struct fuse_req),
2295 0, 0, NULL);
2296 if (!fuse_req_cachep)
2297 goto out;
2298
2299 err = misc_register(&fuse_miscdevice);
2300 if (err)
2301 goto out_cache_clean;
2302
2303 return 0;
2304
2305 out_cache_clean:
2306 kmem_cache_destroy(fuse_req_cachep);
2307 out:
2308 return err;
2309}
2310
2311void fuse_dev_cleanup(void)
2312{
2313 misc_deregister(&fuse_miscdevice);
2314 kmem_cache_destroy(fuse_req_cachep);
2315}