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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
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 matched 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 FR_INTERRUPTED check. Pairs with
292 * smp_mb() from queue_interrupt().
293 */
294 if (test_bit(FR_INTERRUPTED, &req->flags)) {
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 fc->num_background--;
319 fc->active_background--;
320 flush_bg_queue(fc);
321 spin_unlock(&fc->bg_lock);
322 } else {
323 /* Wake up waiter sleeping in request_wait_answer() */
324 wake_up(&req->waitq);
325 }
326
327 if (test_bit(FR_ASYNC, &req->flags))
328 req->args->end(fm, req->args, req->out.h.error);
329put_request:
330 fuse_put_request(req);
331}
332EXPORT_SYMBOL_GPL(fuse_request_end);
333
334static int queue_interrupt(struct fuse_req *req)
335{
336 struct fuse_iqueue *fiq = &req->fm->fc->iq;
337
338 spin_lock(&fiq->lock);
339 /* Check for we've sent request to interrupt this req */
340 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
341 spin_unlock(&fiq->lock);
342 return -EINVAL;
343 }
344
345 if (list_empty(&req->intr_entry)) {
346 list_add_tail(&req->intr_entry, &fiq->interrupts);
347 /*
348 * Pairs with smp_mb() implied by test_and_set_bit()
349 * from fuse_request_end().
350 */
351 smp_mb();
352 if (test_bit(FR_FINISHED, &req->flags)) {
353 list_del_init(&req->intr_entry);
354 spin_unlock(&fiq->lock);
355 return 0;
356 }
357 fiq->ops->wake_interrupt_and_unlock(fiq);
358 } else {
359 spin_unlock(&fiq->lock);
360 }
361 return 0;
362}
363
364static void request_wait_answer(struct fuse_req *req)
365{
366 struct fuse_conn *fc = req->fm->fc;
367 struct fuse_iqueue *fiq = &fc->iq;
368 int err;
369
370 if (!fc->no_interrupt) {
371 /* Any signal may interrupt this */
372 err = wait_event_interruptible(req->waitq,
373 test_bit(FR_FINISHED, &req->flags));
374 if (!err)
375 return;
376
377 set_bit(FR_INTERRUPTED, &req->flags);
378 /* matches barrier in fuse_dev_do_read() */
379 smp_mb__after_atomic();
380 if (test_bit(FR_SENT, &req->flags))
381 queue_interrupt(req);
382 }
383
384 if (!test_bit(FR_FORCE, &req->flags)) {
385 /* Only fatal signals may interrupt this */
386 err = wait_event_killable(req->waitq,
387 test_bit(FR_FINISHED, &req->flags));
388 if (!err)
389 return;
390
391 spin_lock(&fiq->lock);
392 /* Request is not yet in userspace, bail out */
393 if (test_bit(FR_PENDING, &req->flags)) {
394 list_del(&req->list);
395 spin_unlock(&fiq->lock);
396 __fuse_put_request(req);
397 req->out.h.error = -EINTR;
398 return;
399 }
400 spin_unlock(&fiq->lock);
401 }
402
403 /*
404 * Either request is already in userspace, or it was forced.
405 * Wait it out.
406 */
407 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
408}
409
410static void __fuse_request_send(struct fuse_req *req)
411{
412 struct fuse_iqueue *fiq = &req->fm->fc->iq;
413
414 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
415 spin_lock(&fiq->lock);
416 if (!fiq->connected) {
417 spin_unlock(&fiq->lock);
418 req->out.h.error = -ENOTCONN;
419 } else {
420 req->in.h.unique = fuse_get_unique(fiq);
421 /* acquire extra reference, since request is still needed
422 after fuse_request_end() */
423 __fuse_get_request(req);
424 queue_request_and_unlock(fiq, req);
425
426 request_wait_answer(req);
427 /* Pairs with smp_wmb() in fuse_request_end() */
428 smp_rmb();
429 }
430}
431
432static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
433{
434 if (fc->minor < 4 && args->opcode == FUSE_STATFS)
435 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
436
437 if (fc->minor < 9) {
438 switch (args->opcode) {
439 case FUSE_LOOKUP:
440 case FUSE_CREATE:
441 case FUSE_MKNOD:
442 case FUSE_MKDIR:
443 case FUSE_SYMLINK:
444 case FUSE_LINK:
445 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
446 break;
447 case FUSE_GETATTR:
448 case FUSE_SETATTR:
449 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
450 break;
451 }
452 }
453 if (fc->minor < 12) {
454 switch (args->opcode) {
455 case FUSE_CREATE:
456 args->in_args[0].size = sizeof(struct fuse_open_in);
457 break;
458 case FUSE_MKNOD:
459 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
460 break;
461 }
462 }
463}
464
465static void fuse_force_creds(struct fuse_req *req)
466{
467 struct fuse_conn *fc = req->fm->fc;
468
469 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
470 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
471 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
472}
473
474static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
475{
476 req->in.h.opcode = args->opcode;
477 req->in.h.nodeid = args->nodeid;
478 req->args = args;
479 if (args->end)
480 __set_bit(FR_ASYNC, &req->flags);
481}
482
483ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
484{
485 struct fuse_conn *fc = fm->fc;
486 struct fuse_req *req;
487 ssize_t ret;
488
489 if (args->force) {
490 atomic_inc(&fc->num_waiting);
491 req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL);
492
493 if (!args->nocreds)
494 fuse_force_creds(req);
495
496 __set_bit(FR_WAITING, &req->flags);
497 __set_bit(FR_FORCE, &req->flags);
498 } else {
499 WARN_ON(args->nocreds);
500 req = fuse_get_req(fm, false);
501 if (IS_ERR(req))
502 return PTR_ERR(req);
503 }
504
505 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
506 fuse_adjust_compat(fc, args);
507 fuse_args_to_req(req, args);
508
509 if (!args->noreply)
510 __set_bit(FR_ISREPLY, &req->flags);
511 __fuse_request_send(req);
512 ret = req->out.h.error;
513 if (!ret && args->out_argvar) {
514 BUG_ON(args->out_numargs == 0);
515 ret = args->out_args[args->out_numargs - 1].size;
516 }
517 fuse_put_request(req);
518
519 return ret;
520}
521
522static bool fuse_request_queue_background(struct fuse_req *req)
523{
524 struct fuse_mount *fm = req->fm;
525 struct fuse_conn *fc = fm->fc;
526 bool queued = false;
527
528 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
529 if (!test_bit(FR_WAITING, &req->flags)) {
530 __set_bit(FR_WAITING, &req->flags);
531 atomic_inc(&fc->num_waiting);
532 }
533 __set_bit(FR_ISREPLY, &req->flags);
534 spin_lock(&fc->bg_lock);
535 if (likely(fc->connected)) {
536 fc->num_background++;
537 if (fc->num_background == fc->max_background)
538 fc->blocked = 1;
539 list_add_tail(&req->list, &fc->bg_queue);
540 flush_bg_queue(fc);
541 queued = true;
542 }
543 spin_unlock(&fc->bg_lock);
544
545 return queued;
546}
547
548int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
549 gfp_t gfp_flags)
550{
551 struct fuse_req *req;
552
553 if (args->force) {
554 WARN_ON(!args->nocreds);
555 req = fuse_request_alloc(fm, gfp_flags);
556 if (!req)
557 return -ENOMEM;
558 __set_bit(FR_BACKGROUND, &req->flags);
559 } else {
560 WARN_ON(args->nocreds);
561 req = fuse_get_req(fm, true);
562 if (IS_ERR(req))
563 return PTR_ERR(req);
564 }
565
566 fuse_args_to_req(req, args);
567
568 if (!fuse_request_queue_background(req)) {
569 fuse_put_request(req);
570 return -ENOTCONN;
571 }
572
573 return 0;
574}
575EXPORT_SYMBOL_GPL(fuse_simple_background);
576
577static int fuse_simple_notify_reply(struct fuse_mount *fm,
578 struct fuse_args *args, u64 unique)
579{
580 struct fuse_req *req;
581 struct fuse_iqueue *fiq = &fm->fc->iq;
582 int err = 0;
583
584 req = fuse_get_req(fm, false);
585 if (IS_ERR(req))
586 return PTR_ERR(req);
587
588 __clear_bit(FR_ISREPLY, &req->flags);
589 req->in.h.unique = unique;
590
591 fuse_args_to_req(req, args);
592
593 spin_lock(&fiq->lock);
594 if (fiq->connected) {
595 queue_request_and_unlock(fiq, req);
596 } else {
597 err = -ENODEV;
598 spin_unlock(&fiq->lock);
599 fuse_put_request(req);
600 }
601
602 return err;
603}
604
605/*
606 * Lock the request. Up to the next unlock_request() there mustn't be
607 * anything that could cause a page-fault. If the request was already
608 * aborted bail out.
609 */
610static int lock_request(struct fuse_req *req)
611{
612 int err = 0;
613 if (req) {
614 spin_lock(&req->waitq.lock);
615 if (test_bit(FR_ABORTED, &req->flags))
616 err = -ENOENT;
617 else
618 set_bit(FR_LOCKED, &req->flags);
619 spin_unlock(&req->waitq.lock);
620 }
621 return err;
622}
623
624/*
625 * Unlock request. If it was aborted while locked, caller is responsible
626 * for unlocking and ending the request.
627 */
628static int unlock_request(struct fuse_req *req)
629{
630 int err = 0;
631 if (req) {
632 spin_lock(&req->waitq.lock);
633 if (test_bit(FR_ABORTED, &req->flags))
634 err = -ENOENT;
635 else
636 clear_bit(FR_LOCKED, &req->flags);
637 spin_unlock(&req->waitq.lock);
638 }
639 return err;
640}
641
642struct fuse_copy_state {
643 int write;
644 struct fuse_req *req;
645 struct iov_iter *iter;
646 struct pipe_buffer *pipebufs;
647 struct pipe_buffer *currbuf;
648 struct pipe_inode_info *pipe;
649 unsigned long nr_segs;
650 struct page *pg;
651 unsigned len;
652 unsigned offset;
653 unsigned move_pages:1;
654};
655
656static void fuse_copy_init(struct fuse_copy_state *cs, int write,
657 struct iov_iter *iter)
658{
659 memset(cs, 0, sizeof(*cs));
660 cs->write = write;
661 cs->iter = iter;
662}
663
664/* Unmap and put previous page of userspace buffer */
665static void fuse_copy_finish(struct fuse_copy_state *cs)
666{
667 if (cs->currbuf) {
668 struct pipe_buffer *buf = cs->currbuf;
669
670 if (cs->write)
671 buf->len = PAGE_SIZE - cs->len;
672 cs->currbuf = NULL;
673 } else if (cs->pg) {
674 if (cs->write) {
675 flush_dcache_page(cs->pg);
676 set_page_dirty_lock(cs->pg);
677 }
678 put_page(cs->pg);
679 }
680 cs->pg = NULL;
681}
682
683/*
684 * Get another pagefull of userspace buffer, and map it to kernel
685 * address space, and lock request
686 */
687static int fuse_copy_fill(struct fuse_copy_state *cs)
688{
689 struct page *page;
690 int err;
691
692 err = unlock_request(cs->req);
693 if (err)
694 return err;
695
696 fuse_copy_finish(cs);
697 if (cs->pipebufs) {
698 struct pipe_buffer *buf = cs->pipebufs;
699
700 if (!cs->write) {
701 err = pipe_buf_confirm(cs->pipe, buf);
702 if (err)
703 return err;
704
705 BUG_ON(!cs->nr_segs);
706 cs->currbuf = buf;
707 cs->pg = buf->page;
708 cs->offset = buf->offset;
709 cs->len = buf->len;
710 cs->pipebufs++;
711 cs->nr_segs--;
712 } else {
713 if (cs->nr_segs >= cs->pipe->max_usage)
714 return -EIO;
715
716 page = alloc_page(GFP_HIGHUSER);
717 if (!page)
718 return -ENOMEM;
719
720 buf->page = page;
721 buf->offset = 0;
722 buf->len = 0;
723
724 cs->currbuf = buf;
725 cs->pg = page;
726 cs->offset = 0;
727 cs->len = PAGE_SIZE;
728 cs->pipebufs++;
729 cs->nr_segs++;
730 }
731 } else {
732 size_t off;
733 err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off);
734 if (err < 0)
735 return err;
736 BUG_ON(!err);
737 cs->len = err;
738 cs->offset = off;
739 cs->pg = page;
740 }
741
742 return lock_request(cs->req);
743}
744
745/* Do as much copy to/from userspace buffer as we can */
746static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
747{
748 unsigned ncpy = min(*size, cs->len);
749 if (val) {
750 void *pgaddr = kmap_local_page(cs->pg);
751 void *buf = pgaddr + cs->offset;
752
753 if (cs->write)
754 memcpy(buf, *val, ncpy);
755 else
756 memcpy(*val, buf, ncpy);
757
758 kunmap_local(pgaddr);
759 *val += ncpy;
760 }
761 *size -= ncpy;
762 cs->len -= ncpy;
763 cs->offset += ncpy;
764 return ncpy;
765}
766
767static int fuse_check_folio(struct folio *folio)
768{
769 if (folio_mapped(folio) ||
770 folio->mapping != NULL ||
771 (folio->flags & PAGE_FLAGS_CHECK_AT_PREP &
772 ~(1 << PG_locked |
773 1 << PG_referenced |
774 1 << PG_uptodate |
775 1 << PG_lru |
776 1 << PG_active |
777 1 << PG_workingset |
778 1 << PG_reclaim |
779 1 << PG_waiters |
780 LRU_GEN_MASK | LRU_REFS_MASK))) {
781 dump_page(&folio->page, "fuse: trying to steal weird page");
782 return 1;
783 }
784 return 0;
785}
786
787static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
788{
789 int err;
790 struct folio *oldfolio = page_folio(*pagep);
791 struct folio *newfolio;
792 struct pipe_buffer *buf = cs->pipebufs;
793
794 folio_get(oldfolio);
795 err = unlock_request(cs->req);
796 if (err)
797 goto out_put_old;
798
799 fuse_copy_finish(cs);
800
801 err = pipe_buf_confirm(cs->pipe, buf);
802 if (err)
803 goto out_put_old;
804
805 BUG_ON(!cs->nr_segs);
806 cs->currbuf = buf;
807 cs->len = buf->len;
808 cs->pipebufs++;
809 cs->nr_segs--;
810
811 if (cs->len != PAGE_SIZE)
812 goto out_fallback;
813
814 if (!pipe_buf_try_steal(cs->pipe, buf))
815 goto out_fallback;
816
817 newfolio = page_folio(buf->page);
818
819 if (!folio_test_uptodate(newfolio))
820 folio_mark_uptodate(newfolio);
821
822 folio_clear_mappedtodisk(newfolio);
823
824 if (fuse_check_folio(newfolio) != 0)
825 goto out_fallback_unlock;
826
827 /*
828 * This is a new and locked page, it shouldn't be mapped or
829 * have any special flags on it
830 */
831 if (WARN_ON(folio_mapped(oldfolio)))
832 goto out_fallback_unlock;
833 if (WARN_ON(folio_has_private(oldfolio)))
834 goto out_fallback_unlock;
835 if (WARN_ON(folio_test_dirty(oldfolio) ||
836 folio_test_writeback(oldfolio)))
837 goto out_fallback_unlock;
838 if (WARN_ON(folio_test_mlocked(oldfolio)))
839 goto out_fallback_unlock;
840
841 replace_page_cache_folio(oldfolio, newfolio);
842
843 folio_get(newfolio);
844
845 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
846 folio_add_lru(newfolio);
847
848 /*
849 * Release while we have extra ref on stolen page. Otherwise
850 * anon_pipe_buf_release() might think the page can be reused.
851 */
852 pipe_buf_release(cs->pipe, buf);
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 = &newfolio->page;
860 spin_unlock(&cs->req->waitq.lock);
861
862 if (err) {
863 folio_unlock(newfolio);
864 folio_put(newfolio);
865 goto out_put_old;
866 }
867
868 folio_unlock(oldfolio);
869 /* Drop ref for ap->pages[] array */
870 folio_put(oldfolio);
871 cs->len = 0;
872
873 err = 0;
874out_put_old:
875 /* Drop ref obtained in this function */
876 folio_put(oldfolio);
877 return err;
878
879out_fallback_unlock:
880 folio_unlock(newfolio);
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 /*
938 * Can't control lifetime of pipe buffers, so always
939 * copy user pages.
940 */
941 if (cs->req->args->user_pages) {
942 err = fuse_copy_fill(cs);
943 if (err)
944 return err;
945 } else {
946 return fuse_ref_page(cs, page, offset, count);
947 }
948 } else if (!cs->len) {
949 if (cs->move_pages && page &&
950 offset == 0 && count == PAGE_SIZE) {
951 err = fuse_try_move_page(cs, pagep);
952 if (err <= 0)
953 return err;
954 } else {
955 err = fuse_copy_fill(cs);
956 if (err)
957 return err;
958 }
959 }
960 if (page) {
961 void *mapaddr = kmap_local_page(page);
962 void *buf = mapaddr + offset;
963 offset += fuse_copy_do(cs, &buf, &count);
964 kunmap_local(mapaddr);
965 } else
966 offset += fuse_copy_do(cs, NULL, &count);
967 }
968 if (page && !cs->write)
969 flush_dcache_page(page);
970 return 0;
971}
972
973/* Copy pages in the request to/from userspace buffer */
974static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
975 int zeroing)
976{
977 unsigned i;
978 struct fuse_req *req = cs->req;
979 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
980
981
982 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
983 int err;
984 unsigned int offset = ap->descs[i].offset;
985 unsigned int count = min(nbytes, ap->descs[i].length);
986
987 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
988 if (err)
989 return err;
990
991 nbytes -= count;
992 }
993 return 0;
994}
995
996/* Copy a single argument in the request to/from userspace buffer */
997static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
998{
999 while (size) {
1000 if (!cs->len) {
1001 int err = fuse_copy_fill(cs);
1002 if (err)
1003 return err;
1004 }
1005 fuse_copy_do(cs, &val, &size);
1006 }
1007 return 0;
1008}
1009
1010/* Copy request arguments to/from userspace buffer */
1011static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1012 unsigned argpages, struct fuse_arg *args,
1013 int zeroing)
1014{
1015 int err = 0;
1016 unsigned i;
1017
1018 for (i = 0; !err && i < numargs; i++) {
1019 struct fuse_arg *arg = &args[i];
1020 if (i == numargs - 1 && argpages)
1021 err = fuse_copy_pages(cs, arg->size, zeroing);
1022 else
1023 err = fuse_copy_one(cs, arg->value, arg->size);
1024 }
1025 return err;
1026}
1027
1028static int forget_pending(struct fuse_iqueue *fiq)
1029{
1030 return fiq->forget_list_head.next != NULL;
1031}
1032
1033static int request_pending(struct fuse_iqueue *fiq)
1034{
1035 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1036 forget_pending(fiq);
1037}
1038
1039/*
1040 * Transfer an interrupt request to userspace
1041 *
1042 * Unlike other requests this is assembled on demand, without a need
1043 * to allocate a separate fuse_req structure.
1044 *
1045 * Called with fiq->lock held, releases it
1046 */
1047static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1048 struct fuse_copy_state *cs,
1049 size_t nbytes, struct fuse_req *req)
1050__releases(fiq->lock)
1051{
1052 struct fuse_in_header ih;
1053 struct fuse_interrupt_in arg;
1054 unsigned reqsize = sizeof(ih) + sizeof(arg);
1055 int err;
1056
1057 list_del_init(&req->intr_entry);
1058 memset(&ih, 0, sizeof(ih));
1059 memset(&arg, 0, sizeof(arg));
1060 ih.len = reqsize;
1061 ih.opcode = FUSE_INTERRUPT;
1062 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1063 arg.unique = req->in.h.unique;
1064
1065 spin_unlock(&fiq->lock);
1066 if (nbytes < reqsize)
1067 return -EINVAL;
1068
1069 err = fuse_copy_one(cs, &ih, sizeof(ih));
1070 if (!err)
1071 err = fuse_copy_one(cs, &arg, sizeof(arg));
1072 fuse_copy_finish(cs);
1073
1074 return err ? err : reqsize;
1075}
1076
1077struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1078 unsigned int max,
1079 unsigned int *countp)
1080{
1081 struct fuse_forget_link *head = fiq->forget_list_head.next;
1082 struct fuse_forget_link **newhead = &head;
1083 unsigned count;
1084
1085 for (count = 0; *newhead != NULL && count < max; count++)
1086 newhead = &(*newhead)->next;
1087
1088 fiq->forget_list_head.next = *newhead;
1089 *newhead = NULL;
1090 if (fiq->forget_list_head.next == NULL)
1091 fiq->forget_list_tail = &fiq->forget_list_head;
1092
1093 if (countp != NULL)
1094 *countp = count;
1095
1096 return head;
1097}
1098EXPORT_SYMBOL(fuse_dequeue_forget);
1099
1100static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1101 struct fuse_copy_state *cs,
1102 size_t nbytes)
1103__releases(fiq->lock)
1104{
1105 int err;
1106 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1107 struct fuse_forget_in arg = {
1108 .nlookup = forget->forget_one.nlookup,
1109 };
1110 struct fuse_in_header ih = {
1111 .opcode = FUSE_FORGET,
1112 .nodeid = forget->forget_one.nodeid,
1113 .unique = fuse_get_unique(fiq),
1114 .len = sizeof(ih) + sizeof(arg),
1115 };
1116
1117 spin_unlock(&fiq->lock);
1118 kfree(forget);
1119 if (nbytes < ih.len)
1120 return -EINVAL;
1121
1122 err = fuse_copy_one(cs, &ih, sizeof(ih));
1123 if (!err)
1124 err = fuse_copy_one(cs, &arg, sizeof(arg));
1125 fuse_copy_finish(cs);
1126
1127 if (err)
1128 return err;
1129
1130 return ih.len;
1131}
1132
1133static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1134 struct fuse_copy_state *cs, size_t nbytes)
1135__releases(fiq->lock)
1136{
1137 int err;
1138 unsigned max_forgets;
1139 unsigned count;
1140 struct fuse_forget_link *head;
1141 struct fuse_batch_forget_in arg = { .count = 0 };
1142 struct fuse_in_header ih = {
1143 .opcode = FUSE_BATCH_FORGET,
1144 .unique = fuse_get_unique(fiq),
1145 .len = sizeof(ih) + sizeof(arg),
1146 };
1147
1148 if (nbytes < ih.len) {
1149 spin_unlock(&fiq->lock);
1150 return -EINVAL;
1151 }
1152
1153 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1154 head = fuse_dequeue_forget(fiq, max_forgets, &count);
1155 spin_unlock(&fiq->lock);
1156
1157 arg.count = count;
1158 ih.len += count * sizeof(struct fuse_forget_one);
1159 err = fuse_copy_one(cs, &ih, sizeof(ih));
1160 if (!err)
1161 err = fuse_copy_one(cs, &arg, sizeof(arg));
1162
1163 while (head) {
1164 struct fuse_forget_link *forget = head;
1165
1166 if (!err) {
1167 err = fuse_copy_one(cs, &forget->forget_one,
1168 sizeof(forget->forget_one));
1169 }
1170 head = forget->next;
1171 kfree(forget);
1172 }
1173
1174 fuse_copy_finish(cs);
1175
1176 if (err)
1177 return err;
1178
1179 return ih.len;
1180}
1181
1182static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1183 struct fuse_copy_state *cs,
1184 size_t nbytes)
1185__releases(fiq->lock)
1186{
1187 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1188 return fuse_read_single_forget(fiq, cs, nbytes);
1189 else
1190 return fuse_read_batch_forget(fiq, cs, nbytes);
1191}
1192
1193/*
1194 * Read a single request into the userspace filesystem's buffer. This
1195 * function waits until a request is available, then removes it from
1196 * the pending list and copies request data to userspace buffer. If
1197 * no reply is needed (FORGET) or request has been aborted or there
1198 * was an error during the copying then it's finished by calling
1199 * fuse_request_end(). Otherwise add it to the processing list, and set
1200 * the 'sent' flag.
1201 */
1202static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1203 struct fuse_copy_state *cs, size_t nbytes)
1204{
1205 ssize_t err;
1206 struct fuse_conn *fc = fud->fc;
1207 struct fuse_iqueue *fiq = &fc->iq;
1208 struct fuse_pqueue *fpq = &fud->pq;
1209 struct fuse_req *req;
1210 struct fuse_args *args;
1211 unsigned reqsize;
1212 unsigned int hash;
1213
1214 /*
1215 * Require sane minimum read buffer - that has capacity for fixed part
1216 * of any request header + negotiated max_write room for data.
1217 *
1218 * Historically libfuse reserves 4K for fixed header room, but e.g.
1219 * GlusterFS reserves only 80 bytes
1220 *
1221 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1222 *
1223 * which is the absolute minimum any sane filesystem should be using
1224 * for header room.
1225 */
1226 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1227 sizeof(struct fuse_in_header) +
1228 sizeof(struct fuse_write_in) +
1229 fc->max_write))
1230 return -EINVAL;
1231
1232 restart:
1233 for (;;) {
1234 spin_lock(&fiq->lock);
1235 if (!fiq->connected || request_pending(fiq))
1236 break;
1237 spin_unlock(&fiq->lock);
1238
1239 if (file->f_flags & O_NONBLOCK)
1240 return -EAGAIN;
1241 err = wait_event_interruptible_exclusive(fiq->waitq,
1242 !fiq->connected || request_pending(fiq));
1243 if (err)
1244 return err;
1245 }
1246
1247 if (!fiq->connected) {
1248 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1249 goto err_unlock;
1250 }
1251
1252 if (!list_empty(&fiq->interrupts)) {
1253 req = list_entry(fiq->interrupts.next, struct fuse_req,
1254 intr_entry);
1255 return fuse_read_interrupt(fiq, cs, nbytes, req);
1256 }
1257
1258 if (forget_pending(fiq)) {
1259 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1260 return fuse_read_forget(fc, fiq, cs, nbytes);
1261
1262 if (fiq->forget_batch <= -8)
1263 fiq->forget_batch = 16;
1264 }
1265
1266 req = list_entry(fiq->pending.next, struct fuse_req, list);
1267 clear_bit(FR_PENDING, &req->flags);
1268 list_del_init(&req->list);
1269 spin_unlock(&fiq->lock);
1270
1271 args = req->args;
1272 reqsize = req->in.h.len;
1273
1274 /* If request is too large, reply with an error and restart the read */
1275 if (nbytes < reqsize) {
1276 req->out.h.error = -EIO;
1277 /* SETXATTR is special, since it may contain too large data */
1278 if (args->opcode == FUSE_SETXATTR)
1279 req->out.h.error = -E2BIG;
1280 fuse_request_end(req);
1281 goto restart;
1282 }
1283 spin_lock(&fpq->lock);
1284 /*
1285 * Must not put request on fpq->io queue after having been shut down by
1286 * fuse_abort_conn()
1287 */
1288 if (!fpq->connected) {
1289 req->out.h.error = err = -ECONNABORTED;
1290 goto out_end;
1291
1292 }
1293 list_add(&req->list, &fpq->io);
1294 spin_unlock(&fpq->lock);
1295 cs->req = req;
1296 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1297 if (!err)
1298 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1299 (struct fuse_arg *) args->in_args, 0);
1300 fuse_copy_finish(cs);
1301 spin_lock(&fpq->lock);
1302 clear_bit(FR_LOCKED, &req->flags);
1303 if (!fpq->connected) {
1304 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1305 goto out_end;
1306 }
1307 if (err) {
1308 req->out.h.error = -EIO;
1309 goto out_end;
1310 }
1311 if (!test_bit(FR_ISREPLY, &req->flags)) {
1312 err = reqsize;
1313 goto out_end;
1314 }
1315 hash = fuse_req_hash(req->in.h.unique);
1316 list_move_tail(&req->list, &fpq->processing[hash]);
1317 __fuse_get_request(req);
1318 set_bit(FR_SENT, &req->flags);
1319 spin_unlock(&fpq->lock);
1320 /* matches barrier in request_wait_answer() */
1321 smp_mb__after_atomic();
1322 if (test_bit(FR_INTERRUPTED, &req->flags))
1323 queue_interrupt(req);
1324 fuse_put_request(req);
1325
1326 return reqsize;
1327
1328out_end:
1329 if (!test_bit(FR_PRIVATE, &req->flags))
1330 list_del_init(&req->list);
1331 spin_unlock(&fpq->lock);
1332 fuse_request_end(req);
1333 return err;
1334
1335 err_unlock:
1336 spin_unlock(&fiq->lock);
1337 return err;
1338}
1339
1340static int fuse_dev_open(struct inode *inode, struct file *file)
1341{
1342 /*
1343 * The fuse device's file's private_data is used to hold
1344 * the fuse_conn(ection) when it is mounted, and is used to
1345 * keep track of whether the file has been mounted already.
1346 */
1347 file->private_data = NULL;
1348 return 0;
1349}
1350
1351static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1352{
1353 struct fuse_copy_state cs;
1354 struct file *file = iocb->ki_filp;
1355 struct fuse_dev *fud = fuse_get_dev(file);
1356
1357 if (!fud)
1358 return -EPERM;
1359
1360 if (!user_backed_iter(to))
1361 return -EINVAL;
1362
1363 fuse_copy_init(&cs, 1, to);
1364
1365 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1366}
1367
1368static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1369 struct pipe_inode_info *pipe,
1370 size_t len, unsigned int flags)
1371{
1372 int total, ret;
1373 int page_nr = 0;
1374 struct pipe_buffer *bufs;
1375 struct fuse_copy_state cs;
1376 struct fuse_dev *fud = fuse_get_dev(in);
1377
1378 if (!fud)
1379 return -EPERM;
1380
1381 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1382 GFP_KERNEL);
1383 if (!bufs)
1384 return -ENOMEM;
1385
1386 fuse_copy_init(&cs, 1, NULL);
1387 cs.pipebufs = bufs;
1388 cs.pipe = pipe;
1389 ret = fuse_dev_do_read(fud, in, &cs, len);
1390 if (ret < 0)
1391 goto out;
1392
1393 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1394 ret = -EIO;
1395 goto out;
1396 }
1397
1398 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1399 /*
1400 * Need to be careful about this. Having buf->ops in module
1401 * code can Oops if the buffer persists after module unload.
1402 */
1403 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1404 bufs[page_nr].flags = 0;
1405 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1406 if (unlikely(ret < 0))
1407 break;
1408 }
1409 if (total)
1410 ret = total;
1411out:
1412 for (; page_nr < cs.nr_segs; page_nr++)
1413 put_page(bufs[page_nr].page);
1414
1415 kvfree(bufs);
1416 return ret;
1417}
1418
1419static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1420 struct fuse_copy_state *cs)
1421{
1422 struct fuse_notify_poll_wakeup_out outarg;
1423 int err = -EINVAL;
1424
1425 if (size != sizeof(outarg))
1426 goto err;
1427
1428 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1429 if (err)
1430 goto err;
1431
1432 fuse_copy_finish(cs);
1433 return fuse_notify_poll_wakeup(fc, &outarg);
1434
1435err:
1436 fuse_copy_finish(cs);
1437 return err;
1438}
1439
1440static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1441 struct fuse_copy_state *cs)
1442{
1443 struct fuse_notify_inval_inode_out outarg;
1444 int err = -EINVAL;
1445
1446 if (size != sizeof(outarg))
1447 goto err;
1448
1449 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1450 if (err)
1451 goto err;
1452 fuse_copy_finish(cs);
1453
1454 down_read(&fc->killsb);
1455 err = fuse_reverse_inval_inode(fc, outarg.ino,
1456 outarg.off, outarg.len);
1457 up_read(&fc->killsb);
1458 return err;
1459
1460err:
1461 fuse_copy_finish(cs);
1462 return err;
1463}
1464
1465static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1466 struct fuse_copy_state *cs)
1467{
1468 struct fuse_notify_inval_entry_out outarg;
1469 int err = -ENOMEM;
1470 char *buf;
1471 struct qstr name;
1472
1473 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1474 if (!buf)
1475 goto err;
1476
1477 err = -EINVAL;
1478 if (size < sizeof(outarg))
1479 goto err;
1480
1481 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1482 if (err)
1483 goto err;
1484
1485 err = -ENAMETOOLONG;
1486 if (outarg.namelen > FUSE_NAME_MAX)
1487 goto err;
1488
1489 err = -EINVAL;
1490 if (size != sizeof(outarg) + outarg.namelen + 1)
1491 goto err;
1492
1493 name.name = buf;
1494 name.len = outarg.namelen;
1495 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1496 if (err)
1497 goto err;
1498 fuse_copy_finish(cs);
1499 buf[outarg.namelen] = 0;
1500
1501 down_read(&fc->killsb);
1502 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name, outarg.flags);
1503 up_read(&fc->killsb);
1504 kfree(buf);
1505 return err;
1506
1507err:
1508 kfree(buf);
1509 fuse_copy_finish(cs);
1510 return err;
1511}
1512
1513static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1514 struct fuse_copy_state *cs)
1515{
1516 struct fuse_notify_delete_out outarg;
1517 int err = -ENOMEM;
1518 char *buf;
1519 struct qstr name;
1520
1521 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1522 if (!buf)
1523 goto err;
1524
1525 err = -EINVAL;
1526 if (size < sizeof(outarg))
1527 goto err;
1528
1529 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1530 if (err)
1531 goto err;
1532
1533 err = -ENAMETOOLONG;
1534 if (outarg.namelen > FUSE_NAME_MAX)
1535 goto err;
1536
1537 err = -EINVAL;
1538 if (size != sizeof(outarg) + outarg.namelen + 1)
1539 goto err;
1540
1541 name.name = buf;
1542 name.len = outarg.namelen;
1543 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1544 if (err)
1545 goto err;
1546 fuse_copy_finish(cs);
1547 buf[outarg.namelen] = 0;
1548
1549 down_read(&fc->killsb);
1550 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name, 0);
1551 up_read(&fc->killsb);
1552 kfree(buf);
1553 return err;
1554
1555err:
1556 kfree(buf);
1557 fuse_copy_finish(cs);
1558 return err;
1559}
1560
1561static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1562 struct fuse_copy_state *cs)
1563{
1564 struct fuse_notify_store_out outarg;
1565 struct inode *inode;
1566 struct address_space *mapping;
1567 u64 nodeid;
1568 int err;
1569 pgoff_t index;
1570 unsigned int offset;
1571 unsigned int num;
1572 loff_t file_size;
1573 loff_t end;
1574
1575 err = -EINVAL;
1576 if (size < sizeof(outarg))
1577 goto out_finish;
1578
1579 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1580 if (err)
1581 goto out_finish;
1582
1583 err = -EINVAL;
1584 if (size - sizeof(outarg) != outarg.size)
1585 goto out_finish;
1586
1587 nodeid = outarg.nodeid;
1588
1589 down_read(&fc->killsb);
1590
1591 err = -ENOENT;
1592 inode = fuse_ilookup(fc, nodeid, NULL);
1593 if (!inode)
1594 goto out_up_killsb;
1595
1596 mapping = inode->i_mapping;
1597 index = outarg.offset >> PAGE_SHIFT;
1598 offset = outarg.offset & ~PAGE_MASK;
1599 file_size = i_size_read(inode);
1600 end = outarg.offset + outarg.size;
1601 if (end > file_size) {
1602 file_size = end;
1603 fuse_write_update_attr(inode, file_size, outarg.size);
1604 }
1605
1606 num = outarg.size;
1607 while (num) {
1608 struct page *page;
1609 unsigned int this_num;
1610
1611 err = -ENOMEM;
1612 page = find_or_create_page(mapping, index,
1613 mapping_gfp_mask(mapping));
1614 if (!page)
1615 goto out_iput;
1616
1617 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1618 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1619 if (!err && offset == 0 &&
1620 (this_num == PAGE_SIZE || file_size == end))
1621 SetPageUptodate(page);
1622 unlock_page(page);
1623 put_page(page);
1624
1625 if (err)
1626 goto out_iput;
1627
1628 num -= this_num;
1629 offset = 0;
1630 index++;
1631 }
1632
1633 err = 0;
1634
1635out_iput:
1636 iput(inode);
1637out_up_killsb:
1638 up_read(&fc->killsb);
1639out_finish:
1640 fuse_copy_finish(cs);
1641 return err;
1642}
1643
1644struct fuse_retrieve_args {
1645 struct fuse_args_pages ap;
1646 struct fuse_notify_retrieve_in inarg;
1647};
1648
1649static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1650 int error)
1651{
1652 struct fuse_retrieve_args *ra =
1653 container_of(args, typeof(*ra), ap.args);
1654
1655 release_pages(ra->ap.pages, ra->ap.num_pages);
1656 kfree(ra);
1657}
1658
1659static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1660 struct fuse_notify_retrieve_out *outarg)
1661{
1662 int err;
1663 struct address_space *mapping = inode->i_mapping;
1664 pgoff_t index;
1665 loff_t file_size;
1666 unsigned int num;
1667 unsigned int offset;
1668 size_t total_len = 0;
1669 unsigned int num_pages;
1670 struct fuse_conn *fc = fm->fc;
1671 struct fuse_retrieve_args *ra;
1672 size_t args_size = sizeof(*ra);
1673 struct fuse_args_pages *ap;
1674 struct fuse_args *args;
1675
1676 offset = outarg->offset & ~PAGE_MASK;
1677 file_size = i_size_read(inode);
1678
1679 num = min(outarg->size, fc->max_write);
1680 if (outarg->offset > file_size)
1681 num = 0;
1682 else if (outarg->offset + num > file_size)
1683 num = file_size - outarg->offset;
1684
1685 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1686 num_pages = min(num_pages, fc->max_pages);
1687
1688 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1689
1690 ra = kzalloc(args_size, GFP_KERNEL);
1691 if (!ra)
1692 return -ENOMEM;
1693
1694 ap = &ra->ap;
1695 ap->pages = (void *) (ra + 1);
1696 ap->descs = (void *) (ap->pages + num_pages);
1697
1698 args = &ap->args;
1699 args->nodeid = outarg->nodeid;
1700 args->opcode = FUSE_NOTIFY_REPLY;
1701 args->in_numargs = 2;
1702 args->in_pages = true;
1703 args->end = fuse_retrieve_end;
1704
1705 index = outarg->offset >> PAGE_SHIFT;
1706
1707 while (num && ap->num_pages < num_pages) {
1708 struct page *page;
1709 unsigned int this_num;
1710
1711 page = find_get_page(mapping, index);
1712 if (!page)
1713 break;
1714
1715 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1716 ap->pages[ap->num_pages] = page;
1717 ap->descs[ap->num_pages].offset = offset;
1718 ap->descs[ap->num_pages].length = this_num;
1719 ap->num_pages++;
1720
1721 offset = 0;
1722 num -= this_num;
1723 total_len += this_num;
1724 index++;
1725 }
1726 ra->inarg.offset = outarg->offset;
1727 ra->inarg.size = total_len;
1728 args->in_args[0].size = sizeof(ra->inarg);
1729 args->in_args[0].value = &ra->inarg;
1730 args->in_args[1].size = total_len;
1731
1732 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1733 if (err)
1734 fuse_retrieve_end(fm, args, err);
1735
1736 return err;
1737}
1738
1739static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1740 struct fuse_copy_state *cs)
1741{
1742 struct fuse_notify_retrieve_out outarg;
1743 struct fuse_mount *fm;
1744 struct inode *inode;
1745 u64 nodeid;
1746 int err;
1747
1748 err = -EINVAL;
1749 if (size != sizeof(outarg))
1750 goto copy_finish;
1751
1752 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1753 if (err)
1754 goto copy_finish;
1755
1756 fuse_copy_finish(cs);
1757
1758 down_read(&fc->killsb);
1759 err = -ENOENT;
1760 nodeid = outarg.nodeid;
1761
1762 inode = fuse_ilookup(fc, nodeid, &fm);
1763 if (inode) {
1764 err = fuse_retrieve(fm, inode, &outarg);
1765 iput(inode);
1766 }
1767 up_read(&fc->killsb);
1768
1769 return err;
1770
1771copy_finish:
1772 fuse_copy_finish(cs);
1773 return err;
1774}
1775
1776static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1777 unsigned int size, struct fuse_copy_state *cs)
1778{
1779 /* Don't try to move pages (yet) */
1780 cs->move_pages = 0;
1781
1782 switch (code) {
1783 case FUSE_NOTIFY_POLL:
1784 return fuse_notify_poll(fc, size, cs);
1785
1786 case FUSE_NOTIFY_INVAL_INODE:
1787 return fuse_notify_inval_inode(fc, size, cs);
1788
1789 case FUSE_NOTIFY_INVAL_ENTRY:
1790 return fuse_notify_inval_entry(fc, size, cs);
1791
1792 case FUSE_NOTIFY_STORE:
1793 return fuse_notify_store(fc, size, cs);
1794
1795 case FUSE_NOTIFY_RETRIEVE:
1796 return fuse_notify_retrieve(fc, size, cs);
1797
1798 case FUSE_NOTIFY_DELETE:
1799 return fuse_notify_delete(fc, size, cs);
1800
1801 default:
1802 fuse_copy_finish(cs);
1803 return -EINVAL;
1804 }
1805}
1806
1807/* Look up request on processing list by unique ID */
1808static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1809{
1810 unsigned int hash = fuse_req_hash(unique);
1811 struct fuse_req *req;
1812
1813 list_for_each_entry(req, &fpq->processing[hash], list) {
1814 if (req->in.h.unique == unique)
1815 return req;
1816 }
1817 return NULL;
1818}
1819
1820static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1821 unsigned nbytes)
1822{
1823 unsigned reqsize = sizeof(struct fuse_out_header);
1824
1825 reqsize += fuse_len_args(args->out_numargs, args->out_args);
1826
1827 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1828 return -EINVAL;
1829 else if (reqsize > nbytes) {
1830 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1831 unsigned diffsize = reqsize - nbytes;
1832
1833 if (diffsize > lastarg->size)
1834 return -EINVAL;
1835 lastarg->size -= diffsize;
1836 }
1837 return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1838 args->out_args, args->page_zeroing);
1839}
1840
1841/*
1842 * Write a single reply to a request. First the header is copied from
1843 * the write buffer. The request is then searched on the processing
1844 * list by the unique ID found in the header. If found, then remove
1845 * it from the list and copy the rest of the buffer to the request.
1846 * The request is finished by calling fuse_request_end().
1847 */
1848static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1849 struct fuse_copy_state *cs, size_t nbytes)
1850{
1851 int err;
1852 struct fuse_conn *fc = fud->fc;
1853 struct fuse_pqueue *fpq = &fud->pq;
1854 struct fuse_req *req;
1855 struct fuse_out_header oh;
1856
1857 err = -EINVAL;
1858 if (nbytes < sizeof(struct fuse_out_header))
1859 goto out;
1860
1861 err = fuse_copy_one(cs, &oh, sizeof(oh));
1862 if (err)
1863 goto copy_finish;
1864
1865 err = -EINVAL;
1866 if (oh.len != nbytes)
1867 goto copy_finish;
1868
1869 /*
1870 * Zero oh.unique indicates unsolicited notification message
1871 * and error contains notification code.
1872 */
1873 if (!oh.unique) {
1874 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1875 goto out;
1876 }
1877
1878 err = -EINVAL;
1879 if (oh.error <= -512 || oh.error > 0)
1880 goto copy_finish;
1881
1882 spin_lock(&fpq->lock);
1883 req = NULL;
1884 if (fpq->connected)
1885 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1886
1887 err = -ENOENT;
1888 if (!req) {
1889 spin_unlock(&fpq->lock);
1890 goto copy_finish;
1891 }
1892
1893 /* Is it an interrupt reply ID? */
1894 if (oh.unique & FUSE_INT_REQ_BIT) {
1895 __fuse_get_request(req);
1896 spin_unlock(&fpq->lock);
1897
1898 err = 0;
1899 if (nbytes != sizeof(struct fuse_out_header))
1900 err = -EINVAL;
1901 else if (oh.error == -ENOSYS)
1902 fc->no_interrupt = 1;
1903 else if (oh.error == -EAGAIN)
1904 err = queue_interrupt(req);
1905
1906 fuse_put_request(req);
1907
1908 goto copy_finish;
1909 }
1910
1911 clear_bit(FR_SENT, &req->flags);
1912 list_move(&req->list, &fpq->io);
1913 req->out.h = oh;
1914 set_bit(FR_LOCKED, &req->flags);
1915 spin_unlock(&fpq->lock);
1916 cs->req = req;
1917 if (!req->args->page_replace)
1918 cs->move_pages = 0;
1919
1920 if (oh.error)
1921 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1922 else
1923 err = copy_out_args(cs, req->args, nbytes);
1924 fuse_copy_finish(cs);
1925
1926 spin_lock(&fpq->lock);
1927 clear_bit(FR_LOCKED, &req->flags);
1928 if (!fpq->connected)
1929 err = -ENOENT;
1930 else if (err)
1931 req->out.h.error = -EIO;
1932 if (!test_bit(FR_PRIVATE, &req->flags))
1933 list_del_init(&req->list);
1934 spin_unlock(&fpq->lock);
1935
1936 fuse_request_end(req);
1937out:
1938 return err ? err : nbytes;
1939
1940copy_finish:
1941 fuse_copy_finish(cs);
1942 goto out;
1943}
1944
1945static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1946{
1947 struct fuse_copy_state cs;
1948 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1949
1950 if (!fud)
1951 return -EPERM;
1952
1953 if (!user_backed_iter(from))
1954 return -EINVAL;
1955
1956 fuse_copy_init(&cs, 0, from);
1957
1958 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1959}
1960
1961static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1962 struct file *out, loff_t *ppos,
1963 size_t len, unsigned int flags)
1964{
1965 unsigned int head, tail, mask, count;
1966 unsigned nbuf;
1967 unsigned idx;
1968 struct pipe_buffer *bufs;
1969 struct fuse_copy_state cs;
1970 struct fuse_dev *fud;
1971 size_t rem;
1972 ssize_t ret;
1973
1974 fud = fuse_get_dev(out);
1975 if (!fud)
1976 return -EPERM;
1977
1978 pipe_lock(pipe);
1979
1980 head = pipe->head;
1981 tail = pipe->tail;
1982 mask = pipe->ring_size - 1;
1983 count = head - tail;
1984
1985 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1986 if (!bufs) {
1987 pipe_unlock(pipe);
1988 return -ENOMEM;
1989 }
1990
1991 nbuf = 0;
1992 rem = 0;
1993 for (idx = tail; idx != head && rem < len; idx++)
1994 rem += pipe->bufs[idx & mask].len;
1995
1996 ret = -EINVAL;
1997 if (rem < len)
1998 goto out_free;
1999
2000 rem = len;
2001 while (rem) {
2002 struct pipe_buffer *ibuf;
2003 struct pipe_buffer *obuf;
2004
2005 if (WARN_ON(nbuf >= count || tail == head))
2006 goto out_free;
2007
2008 ibuf = &pipe->bufs[tail & mask];
2009 obuf = &bufs[nbuf];
2010
2011 if (rem >= ibuf->len) {
2012 *obuf = *ibuf;
2013 ibuf->ops = NULL;
2014 tail++;
2015 pipe->tail = tail;
2016 } else {
2017 if (!pipe_buf_get(pipe, ibuf))
2018 goto out_free;
2019
2020 *obuf = *ibuf;
2021 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2022 obuf->len = rem;
2023 ibuf->offset += obuf->len;
2024 ibuf->len -= obuf->len;
2025 }
2026 nbuf++;
2027 rem -= obuf->len;
2028 }
2029 pipe_unlock(pipe);
2030
2031 fuse_copy_init(&cs, 0, NULL);
2032 cs.pipebufs = bufs;
2033 cs.nr_segs = nbuf;
2034 cs.pipe = pipe;
2035
2036 if (flags & SPLICE_F_MOVE)
2037 cs.move_pages = 1;
2038
2039 ret = fuse_dev_do_write(fud, &cs, len);
2040
2041 pipe_lock(pipe);
2042out_free:
2043 for (idx = 0; idx < nbuf; idx++) {
2044 struct pipe_buffer *buf = &bufs[idx];
2045
2046 if (buf->ops)
2047 pipe_buf_release(pipe, buf);
2048 }
2049 pipe_unlock(pipe);
2050
2051 kvfree(bufs);
2052 return ret;
2053}
2054
2055static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2056{
2057 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2058 struct fuse_iqueue *fiq;
2059 struct fuse_dev *fud = fuse_get_dev(file);
2060
2061 if (!fud)
2062 return EPOLLERR;
2063
2064 fiq = &fud->fc->iq;
2065 poll_wait(file, &fiq->waitq, wait);
2066
2067 spin_lock(&fiq->lock);
2068 if (!fiq->connected)
2069 mask = EPOLLERR;
2070 else if (request_pending(fiq))
2071 mask |= EPOLLIN | EPOLLRDNORM;
2072 spin_unlock(&fiq->lock);
2073
2074 return mask;
2075}
2076
2077/* Abort all requests on the given list (pending or processing) */
2078static void end_requests(struct list_head *head)
2079{
2080 while (!list_empty(head)) {
2081 struct fuse_req *req;
2082 req = list_entry(head->next, struct fuse_req, list);
2083 req->out.h.error = -ECONNABORTED;
2084 clear_bit(FR_SENT, &req->flags);
2085 list_del_init(&req->list);
2086 fuse_request_end(req);
2087 }
2088}
2089
2090static void end_polls(struct fuse_conn *fc)
2091{
2092 struct rb_node *p;
2093
2094 p = rb_first(&fc->polled_files);
2095
2096 while (p) {
2097 struct fuse_file *ff;
2098 ff = rb_entry(p, struct fuse_file, polled_node);
2099 wake_up_interruptible_all(&ff->poll_wait);
2100
2101 p = rb_next(p);
2102 }
2103}
2104
2105/*
2106 * Abort all requests.
2107 *
2108 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2109 * filesystem.
2110 *
2111 * The same effect is usually achievable through killing the filesystem daemon
2112 * and all users of the filesystem. The exception is the combination of an
2113 * asynchronous request and the tricky deadlock (see
2114 * Documentation/filesystems/fuse.rst).
2115 *
2116 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2117 * requests, they should be finished off immediately. Locked requests will be
2118 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2119 * requests. It is possible that some request will finish before we can. This
2120 * is OK, the request will in that case be removed from the list before we touch
2121 * it.
2122 */
2123void fuse_abort_conn(struct fuse_conn *fc)
2124{
2125 struct fuse_iqueue *fiq = &fc->iq;
2126
2127 spin_lock(&fc->lock);
2128 if (fc->connected) {
2129 struct fuse_dev *fud;
2130 struct fuse_req *req, *next;
2131 LIST_HEAD(to_end);
2132 unsigned int i;
2133
2134 /* Background queuing checks fc->connected under bg_lock */
2135 spin_lock(&fc->bg_lock);
2136 fc->connected = 0;
2137 spin_unlock(&fc->bg_lock);
2138
2139 fuse_set_initialized(fc);
2140 list_for_each_entry(fud, &fc->devices, entry) {
2141 struct fuse_pqueue *fpq = &fud->pq;
2142
2143 spin_lock(&fpq->lock);
2144 fpq->connected = 0;
2145 list_for_each_entry_safe(req, next, &fpq->io, list) {
2146 req->out.h.error = -ECONNABORTED;
2147 spin_lock(&req->waitq.lock);
2148 set_bit(FR_ABORTED, &req->flags);
2149 if (!test_bit(FR_LOCKED, &req->flags)) {
2150 set_bit(FR_PRIVATE, &req->flags);
2151 __fuse_get_request(req);
2152 list_move(&req->list, &to_end);
2153 }
2154 spin_unlock(&req->waitq.lock);
2155 }
2156 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2157 list_splice_tail_init(&fpq->processing[i],
2158 &to_end);
2159 spin_unlock(&fpq->lock);
2160 }
2161 spin_lock(&fc->bg_lock);
2162 fc->blocked = 0;
2163 fc->max_background = UINT_MAX;
2164 flush_bg_queue(fc);
2165 spin_unlock(&fc->bg_lock);
2166
2167 spin_lock(&fiq->lock);
2168 fiq->connected = 0;
2169 list_for_each_entry(req, &fiq->pending, list)
2170 clear_bit(FR_PENDING, &req->flags);
2171 list_splice_tail_init(&fiq->pending, &to_end);
2172 while (forget_pending(fiq))
2173 kfree(fuse_dequeue_forget(fiq, 1, NULL));
2174 wake_up_all(&fiq->waitq);
2175 spin_unlock(&fiq->lock);
2176 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2177 end_polls(fc);
2178 wake_up_all(&fc->blocked_waitq);
2179 spin_unlock(&fc->lock);
2180
2181 end_requests(&to_end);
2182 } else {
2183 spin_unlock(&fc->lock);
2184 }
2185}
2186EXPORT_SYMBOL_GPL(fuse_abort_conn);
2187
2188void fuse_wait_aborted(struct fuse_conn *fc)
2189{
2190 /* matches implicit memory barrier in fuse_drop_waiting() */
2191 smp_mb();
2192 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2193}
2194
2195int fuse_dev_release(struct inode *inode, struct file *file)
2196{
2197 struct fuse_dev *fud = fuse_get_dev(file);
2198
2199 if (fud) {
2200 struct fuse_conn *fc = fud->fc;
2201 struct fuse_pqueue *fpq = &fud->pq;
2202 LIST_HEAD(to_end);
2203 unsigned int i;
2204
2205 spin_lock(&fpq->lock);
2206 WARN_ON(!list_empty(&fpq->io));
2207 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2208 list_splice_init(&fpq->processing[i], &to_end);
2209 spin_unlock(&fpq->lock);
2210
2211 end_requests(&to_end);
2212
2213 /* Are we the last open device? */
2214 if (atomic_dec_and_test(&fc->dev_count)) {
2215 WARN_ON(fc->iq.fasync != NULL);
2216 fuse_abort_conn(fc);
2217 }
2218 fuse_dev_free(fud);
2219 }
2220 return 0;
2221}
2222EXPORT_SYMBOL_GPL(fuse_dev_release);
2223
2224static int fuse_dev_fasync(int fd, struct file *file, int on)
2225{
2226 struct fuse_dev *fud = fuse_get_dev(file);
2227
2228 if (!fud)
2229 return -EPERM;
2230
2231 /* No locking - fasync_helper does its own locking */
2232 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2233}
2234
2235static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2236{
2237 struct fuse_dev *fud;
2238
2239 if (new->private_data)
2240 return -EINVAL;
2241
2242 fud = fuse_dev_alloc_install(fc);
2243 if (!fud)
2244 return -ENOMEM;
2245
2246 new->private_data = fud;
2247 atomic_inc(&fc->dev_count);
2248
2249 return 0;
2250}
2251
2252static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2253 unsigned long arg)
2254{
2255 int res;
2256 int oldfd;
2257 struct fuse_dev *fud = NULL;
2258
2259 switch (cmd) {
2260 case FUSE_DEV_IOC_CLONE:
2261 res = -EFAULT;
2262 if (!get_user(oldfd, (__u32 __user *)arg)) {
2263 struct file *old = fget(oldfd);
2264
2265 res = -EINVAL;
2266 if (old) {
2267 /*
2268 * Check against file->f_op because CUSE
2269 * uses the same ioctl handler.
2270 */
2271 if (old->f_op == file->f_op)
2272 fud = fuse_get_dev(old);
2273
2274 if (fud) {
2275 mutex_lock(&fuse_mutex);
2276 res = fuse_device_clone(fud->fc, file);
2277 mutex_unlock(&fuse_mutex);
2278 }
2279 fput(old);
2280 }
2281 }
2282 break;
2283 default:
2284 res = -ENOTTY;
2285 break;
2286 }
2287 return res;
2288}
2289
2290const struct file_operations fuse_dev_operations = {
2291 .owner = THIS_MODULE,
2292 .open = fuse_dev_open,
2293 .llseek = no_llseek,
2294 .read_iter = fuse_dev_read,
2295 .splice_read = fuse_dev_splice_read,
2296 .write_iter = fuse_dev_write,
2297 .splice_write = fuse_dev_splice_write,
2298 .poll = fuse_dev_poll,
2299 .release = fuse_dev_release,
2300 .fasync = fuse_dev_fasync,
2301 .unlocked_ioctl = fuse_dev_ioctl,
2302 .compat_ioctl = compat_ptr_ioctl,
2303};
2304EXPORT_SYMBOL_GPL(fuse_dev_operations);
2305
2306static struct miscdevice fuse_miscdevice = {
2307 .minor = FUSE_MINOR,
2308 .name = "fuse",
2309 .fops = &fuse_dev_operations,
2310};
2311
2312int __init fuse_dev_init(void)
2313{
2314 int err = -ENOMEM;
2315 fuse_req_cachep = kmem_cache_create("fuse_request",
2316 sizeof(struct fuse_req),
2317 0, 0, NULL);
2318 if (!fuse_req_cachep)
2319 goto out;
2320
2321 err = misc_register(&fuse_miscdevice);
2322 if (err)
2323 goto out_cache_clean;
2324
2325 return 0;
2326
2327 out_cache_clean:
2328 kmem_cache_destroy(fuse_req_cachep);
2329 out:
2330 return err;
2331}
2332
2333void fuse_dev_cleanup(void)
2334{
2335 misc_deregister(&fuse_miscdevice);
2336 kmem_cache_destroy(fuse_req_cachep);
2337}
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
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 matched 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 FR_INTERRUPTED check. Pairs with
292 * smp_mb() from queue_interrupt().
293 */
294 if (test_bit(FR_INTERRUPTED, &req->flags)) {
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_workingset |
787 1 << PG_reclaim |
788 1 << PG_waiters))) {
789 dump_page(page, "fuse: trying to steal weird page");
790 return 1;
791 }
792 return 0;
793}
794
795static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
796{
797 int err;
798 struct page *oldpage = *pagep;
799 struct page *newpage;
800 struct pipe_buffer *buf = cs->pipebufs;
801
802 get_page(oldpage);
803 err = unlock_request(cs->req);
804 if (err)
805 goto out_put_old;
806
807 fuse_copy_finish(cs);
808
809 err = pipe_buf_confirm(cs->pipe, buf);
810 if (err)
811 goto out_put_old;
812
813 BUG_ON(!cs->nr_segs);
814 cs->currbuf = buf;
815 cs->len = buf->len;
816 cs->pipebufs++;
817 cs->nr_segs--;
818
819 if (cs->len != PAGE_SIZE)
820 goto out_fallback;
821
822 if (!pipe_buf_try_steal(cs->pipe, buf))
823 goto out_fallback;
824
825 newpage = buf->page;
826
827 if (!PageUptodate(newpage))
828 SetPageUptodate(newpage);
829
830 ClearPageMappedToDisk(newpage);
831
832 if (fuse_check_page(newpage) != 0)
833 goto out_fallback_unlock;
834
835 /*
836 * This is a new and locked page, it shouldn't be mapped or
837 * have any special flags on it
838 */
839 if (WARN_ON(page_mapped(oldpage)))
840 goto out_fallback_unlock;
841 if (WARN_ON(page_has_private(oldpage)))
842 goto out_fallback_unlock;
843 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
844 goto out_fallback_unlock;
845 if (WARN_ON(PageMlocked(oldpage)))
846 goto out_fallback_unlock;
847
848 replace_page_cache_page(oldpage, newpage);
849
850 get_page(newpage);
851
852 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
853 lru_cache_add(newpage);
854
855 err = 0;
856 spin_lock(&cs->req->waitq.lock);
857 if (test_bit(FR_ABORTED, &cs->req->flags))
858 err = -ENOENT;
859 else
860 *pagep = newpage;
861 spin_unlock(&cs->req->waitq.lock);
862
863 if (err) {
864 unlock_page(newpage);
865 put_page(newpage);
866 goto out_put_old;
867 }
868
869 unlock_page(oldpage);
870 /* Drop ref for ap->pages[] array */
871 put_page(oldpage);
872 cs->len = 0;
873
874 err = 0;
875out_put_old:
876 /* Drop ref obtained in this function */
877 put_page(oldpage);
878 return err;
879
880out_fallback_unlock:
881 unlock_page(newpage);
882out_fallback:
883 cs->pg = buf->page;
884 cs->offset = buf->offset;
885
886 err = lock_request(cs->req);
887 if (!err)
888 err = 1;
889
890 goto out_put_old;
891}
892
893static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
894 unsigned offset, unsigned count)
895{
896 struct pipe_buffer *buf;
897 int err;
898
899 if (cs->nr_segs >= cs->pipe->max_usage)
900 return -EIO;
901
902 get_page(page);
903 err = unlock_request(cs->req);
904 if (err) {
905 put_page(page);
906 return err;
907 }
908
909 fuse_copy_finish(cs);
910
911 buf = cs->pipebufs;
912 buf->page = page;
913 buf->offset = offset;
914 buf->len = count;
915
916 cs->pipebufs++;
917 cs->nr_segs++;
918 cs->len = 0;
919
920 return 0;
921}
922
923/*
924 * Copy a page in the request to/from the userspace buffer. Must be
925 * done atomically
926 */
927static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
928 unsigned offset, unsigned count, int zeroing)
929{
930 int err;
931 struct page *page = *pagep;
932
933 if (page && zeroing && count < PAGE_SIZE)
934 clear_highpage(page);
935
936 while (count) {
937 if (cs->write && cs->pipebufs && page) {
938 return fuse_ref_page(cs, page, offset, count);
939 } else if (!cs->len) {
940 if (cs->move_pages && page &&
941 offset == 0 && count == PAGE_SIZE) {
942 err = fuse_try_move_page(cs, pagep);
943 if (err <= 0)
944 return err;
945 } else {
946 err = fuse_copy_fill(cs);
947 if (err)
948 return err;
949 }
950 }
951 if (page) {
952 void *mapaddr = kmap_atomic(page);
953 void *buf = mapaddr + offset;
954 offset += fuse_copy_do(cs, &buf, &count);
955 kunmap_atomic(mapaddr);
956 } else
957 offset += fuse_copy_do(cs, NULL, &count);
958 }
959 if (page && !cs->write)
960 flush_dcache_page(page);
961 return 0;
962}
963
964/* Copy pages in the request to/from userspace buffer */
965static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
966 int zeroing)
967{
968 unsigned i;
969 struct fuse_req *req = cs->req;
970 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
971
972
973 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
974 int err;
975 unsigned int offset = ap->descs[i].offset;
976 unsigned int count = min(nbytes, ap->descs[i].length);
977
978 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
979 if (err)
980 return err;
981
982 nbytes -= count;
983 }
984 return 0;
985}
986
987/* Copy a single argument in the request to/from userspace buffer */
988static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
989{
990 while (size) {
991 if (!cs->len) {
992 int err = fuse_copy_fill(cs);
993 if (err)
994 return err;
995 }
996 fuse_copy_do(cs, &val, &size);
997 }
998 return 0;
999}
1000
1001/* Copy request arguments to/from userspace buffer */
1002static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1003 unsigned argpages, struct fuse_arg *args,
1004 int zeroing)
1005{
1006 int err = 0;
1007 unsigned i;
1008
1009 for (i = 0; !err && i < numargs; i++) {
1010 struct fuse_arg *arg = &args[i];
1011 if (i == numargs - 1 && argpages)
1012 err = fuse_copy_pages(cs, arg->size, zeroing);
1013 else
1014 err = fuse_copy_one(cs, arg->value, arg->size);
1015 }
1016 return err;
1017}
1018
1019static int forget_pending(struct fuse_iqueue *fiq)
1020{
1021 return fiq->forget_list_head.next != NULL;
1022}
1023
1024static int request_pending(struct fuse_iqueue *fiq)
1025{
1026 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1027 forget_pending(fiq);
1028}
1029
1030/*
1031 * Transfer an interrupt request to userspace
1032 *
1033 * Unlike other requests this is assembled on demand, without a need
1034 * to allocate a separate fuse_req structure.
1035 *
1036 * Called with fiq->lock held, releases it
1037 */
1038static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1039 struct fuse_copy_state *cs,
1040 size_t nbytes, struct fuse_req *req)
1041__releases(fiq->lock)
1042{
1043 struct fuse_in_header ih;
1044 struct fuse_interrupt_in arg;
1045 unsigned reqsize = sizeof(ih) + sizeof(arg);
1046 int err;
1047
1048 list_del_init(&req->intr_entry);
1049 memset(&ih, 0, sizeof(ih));
1050 memset(&arg, 0, sizeof(arg));
1051 ih.len = reqsize;
1052 ih.opcode = FUSE_INTERRUPT;
1053 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1054 arg.unique = req->in.h.unique;
1055
1056 spin_unlock(&fiq->lock);
1057 if (nbytes < reqsize)
1058 return -EINVAL;
1059
1060 err = fuse_copy_one(cs, &ih, sizeof(ih));
1061 if (!err)
1062 err = fuse_copy_one(cs, &arg, sizeof(arg));
1063 fuse_copy_finish(cs);
1064
1065 return err ? err : reqsize;
1066}
1067
1068struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1069 unsigned int max,
1070 unsigned int *countp)
1071{
1072 struct fuse_forget_link *head = fiq->forget_list_head.next;
1073 struct fuse_forget_link **newhead = &head;
1074 unsigned count;
1075
1076 for (count = 0; *newhead != NULL && count < max; count++)
1077 newhead = &(*newhead)->next;
1078
1079 fiq->forget_list_head.next = *newhead;
1080 *newhead = NULL;
1081 if (fiq->forget_list_head.next == NULL)
1082 fiq->forget_list_tail = &fiq->forget_list_head;
1083
1084 if (countp != NULL)
1085 *countp = count;
1086
1087 return head;
1088}
1089EXPORT_SYMBOL(fuse_dequeue_forget);
1090
1091static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1092 struct fuse_copy_state *cs,
1093 size_t nbytes)
1094__releases(fiq->lock)
1095{
1096 int err;
1097 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1098 struct fuse_forget_in arg = {
1099 .nlookup = forget->forget_one.nlookup,
1100 };
1101 struct fuse_in_header ih = {
1102 .opcode = FUSE_FORGET,
1103 .nodeid = forget->forget_one.nodeid,
1104 .unique = fuse_get_unique(fiq),
1105 .len = sizeof(ih) + sizeof(arg),
1106 };
1107
1108 spin_unlock(&fiq->lock);
1109 kfree(forget);
1110 if (nbytes < ih.len)
1111 return -EINVAL;
1112
1113 err = fuse_copy_one(cs, &ih, sizeof(ih));
1114 if (!err)
1115 err = fuse_copy_one(cs, &arg, sizeof(arg));
1116 fuse_copy_finish(cs);
1117
1118 if (err)
1119 return err;
1120
1121 return ih.len;
1122}
1123
1124static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1125 struct fuse_copy_state *cs, size_t nbytes)
1126__releases(fiq->lock)
1127{
1128 int err;
1129 unsigned max_forgets;
1130 unsigned count;
1131 struct fuse_forget_link *head;
1132 struct fuse_batch_forget_in arg = { .count = 0 };
1133 struct fuse_in_header ih = {
1134 .opcode = FUSE_BATCH_FORGET,
1135 .unique = fuse_get_unique(fiq),
1136 .len = sizeof(ih) + sizeof(arg),
1137 };
1138
1139 if (nbytes < ih.len) {
1140 spin_unlock(&fiq->lock);
1141 return -EINVAL;
1142 }
1143
1144 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1145 head = fuse_dequeue_forget(fiq, max_forgets, &count);
1146 spin_unlock(&fiq->lock);
1147
1148 arg.count = count;
1149 ih.len += count * sizeof(struct fuse_forget_one);
1150 err = fuse_copy_one(cs, &ih, sizeof(ih));
1151 if (!err)
1152 err = fuse_copy_one(cs, &arg, sizeof(arg));
1153
1154 while (head) {
1155 struct fuse_forget_link *forget = head;
1156
1157 if (!err) {
1158 err = fuse_copy_one(cs, &forget->forget_one,
1159 sizeof(forget->forget_one));
1160 }
1161 head = forget->next;
1162 kfree(forget);
1163 }
1164
1165 fuse_copy_finish(cs);
1166
1167 if (err)
1168 return err;
1169
1170 return ih.len;
1171}
1172
1173static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1174 struct fuse_copy_state *cs,
1175 size_t nbytes)
1176__releases(fiq->lock)
1177{
1178 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1179 return fuse_read_single_forget(fiq, cs, nbytes);
1180 else
1181 return fuse_read_batch_forget(fiq, cs, nbytes);
1182}
1183
1184/*
1185 * Read a single request into the userspace filesystem's buffer. This
1186 * function waits until a request is available, then removes it from
1187 * the pending list and copies request data to userspace buffer. If
1188 * no reply is needed (FORGET) or request has been aborted or there
1189 * was an error during the copying then it's finished by calling
1190 * fuse_request_end(). Otherwise add it to the processing list, and set
1191 * the 'sent' flag.
1192 */
1193static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1194 struct fuse_copy_state *cs, size_t nbytes)
1195{
1196 ssize_t err;
1197 struct fuse_conn *fc = fud->fc;
1198 struct fuse_iqueue *fiq = &fc->iq;
1199 struct fuse_pqueue *fpq = &fud->pq;
1200 struct fuse_req *req;
1201 struct fuse_args *args;
1202 unsigned reqsize;
1203 unsigned int hash;
1204
1205 /*
1206 * Require sane minimum read buffer - that has capacity for fixed part
1207 * of any request header + negotiated max_write room for data.
1208 *
1209 * Historically libfuse reserves 4K for fixed header room, but e.g.
1210 * GlusterFS reserves only 80 bytes
1211 *
1212 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1213 *
1214 * which is the absolute minimum any sane filesystem should be using
1215 * for header room.
1216 */
1217 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1218 sizeof(struct fuse_in_header) +
1219 sizeof(struct fuse_write_in) +
1220 fc->max_write))
1221 return -EINVAL;
1222
1223 restart:
1224 for (;;) {
1225 spin_lock(&fiq->lock);
1226 if (!fiq->connected || request_pending(fiq))
1227 break;
1228 spin_unlock(&fiq->lock);
1229
1230 if (file->f_flags & O_NONBLOCK)
1231 return -EAGAIN;
1232 err = wait_event_interruptible_exclusive(fiq->waitq,
1233 !fiq->connected || request_pending(fiq));
1234 if (err)
1235 return err;
1236 }
1237
1238 if (!fiq->connected) {
1239 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1240 goto err_unlock;
1241 }
1242
1243 if (!list_empty(&fiq->interrupts)) {
1244 req = list_entry(fiq->interrupts.next, struct fuse_req,
1245 intr_entry);
1246 return fuse_read_interrupt(fiq, cs, nbytes, req);
1247 }
1248
1249 if (forget_pending(fiq)) {
1250 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1251 return fuse_read_forget(fc, fiq, cs, nbytes);
1252
1253 if (fiq->forget_batch <= -8)
1254 fiq->forget_batch = 16;
1255 }
1256
1257 req = list_entry(fiq->pending.next, struct fuse_req, list);
1258 clear_bit(FR_PENDING, &req->flags);
1259 list_del_init(&req->list);
1260 spin_unlock(&fiq->lock);
1261
1262 args = req->args;
1263 reqsize = req->in.h.len;
1264
1265 /* If request is too large, reply with an error and restart the read */
1266 if (nbytes < reqsize) {
1267 req->out.h.error = -EIO;
1268 /* SETXATTR is special, since it may contain too large data */
1269 if (args->opcode == FUSE_SETXATTR)
1270 req->out.h.error = -E2BIG;
1271 fuse_request_end(req);
1272 goto restart;
1273 }
1274 spin_lock(&fpq->lock);
1275 /*
1276 * Must not put request on fpq->io queue after having been shut down by
1277 * fuse_abort_conn()
1278 */
1279 if (!fpq->connected) {
1280 req->out.h.error = err = -ECONNABORTED;
1281 goto out_end;
1282
1283 }
1284 list_add(&req->list, &fpq->io);
1285 spin_unlock(&fpq->lock);
1286 cs->req = req;
1287 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1288 if (!err)
1289 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1290 (struct fuse_arg *) args->in_args, 0);
1291 fuse_copy_finish(cs);
1292 spin_lock(&fpq->lock);
1293 clear_bit(FR_LOCKED, &req->flags);
1294 if (!fpq->connected) {
1295 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1296 goto out_end;
1297 }
1298 if (err) {
1299 req->out.h.error = -EIO;
1300 goto out_end;
1301 }
1302 if (!test_bit(FR_ISREPLY, &req->flags)) {
1303 err = reqsize;
1304 goto out_end;
1305 }
1306 hash = fuse_req_hash(req->in.h.unique);
1307 list_move_tail(&req->list, &fpq->processing[hash]);
1308 __fuse_get_request(req);
1309 set_bit(FR_SENT, &req->flags);
1310 spin_unlock(&fpq->lock);
1311 /* matches barrier in request_wait_answer() */
1312 smp_mb__after_atomic();
1313 if (test_bit(FR_INTERRUPTED, &req->flags))
1314 queue_interrupt(req);
1315 fuse_put_request(req);
1316
1317 return reqsize;
1318
1319out_end:
1320 if (!test_bit(FR_PRIVATE, &req->flags))
1321 list_del_init(&req->list);
1322 spin_unlock(&fpq->lock);
1323 fuse_request_end(req);
1324 return err;
1325
1326 err_unlock:
1327 spin_unlock(&fiq->lock);
1328 return err;
1329}
1330
1331static int fuse_dev_open(struct inode *inode, struct file *file)
1332{
1333 /*
1334 * The fuse device's file's private_data is used to hold
1335 * the fuse_conn(ection) when it is mounted, and is used to
1336 * keep track of whether the file has been mounted already.
1337 */
1338 file->private_data = NULL;
1339 return 0;
1340}
1341
1342static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1343{
1344 struct fuse_copy_state cs;
1345 struct file *file = iocb->ki_filp;
1346 struct fuse_dev *fud = fuse_get_dev(file);
1347
1348 if (!fud)
1349 return -EPERM;
1350
1351 if (!iter_is_iovec(to))
1352 return -EINVAL;
1353
1354 fuse_copy_init(&cs, 1, to);
1355
1356 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1357}
1358
1359static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1360 struct pipe_inode_info *pipe,
1361 size_t len, unsigned int flags)
1362{
1363 int total, ret;
1364 int page_nr = 0;
1365 struct pipe_buffer *bufs;
1366 struct fuse_copy_state cs;
1367 struct fuse_dev *fud = fuse_get_dev(in);
1368
1369 if (!fud)
1370 return -EPERM;
1371
1372 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1373 GFP_KERNEL);
1374 if (!bufs)
1375 return -ENOMEM;
1376
1377 fuse_copy_init(&cs, 1, NULL);
1378 cs.pipebufs = bufs;
1379 cs.pipe = pipe;
1380 ret = fuse_dev_do_read(fud, in, &cs, len);
1381 if (ret < 0)
1382 goto out;
1383
1384 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1385 ret = -EIO;
1386 goto out;
1387 }
1388
1389 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1390 /*
1391 * Need to be careful about this. Having buf->ops in module
1392 * code can Oops if the buffer persists after module unload.
1393 */
1394 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1395 bufs[page_nr].flags = 0;
1396 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1397 if (unlikely(ret < 0))
1398 break;
1399 }
1400 if (total)
1401 ret = total;
1402out:
1403 for (; page_nr < cs.nr_segs; page_nr++)
1404 put_page(bufs[page_nr].page);
1405
1406 kvfree(bufs);
1407 return ret;
1408}
1409
1410static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1411 struct fuse_copy_state *cs)
1412{
1413 struct fuse_notify_poll_wakeup_out outarg;
1414 int err = -EINVAL;
1415
1416 if (size != sizeof(outarg))
1417 goto err;
1418
1419 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1420 if (err)
1421 goto err;
1422
1423 fuse_copy_finish(cs);
1424 return fuse_notify_poll_wakeup(fc, &outarg);
1425
1426err:
1427 fuse_copy_finish(cs);
1428 return err;
1429}
1430
1431static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1432 struct fuse_copy_state *cs)
1433{
1434 struct fuse_notify_inval_inode_out outarg;
1435 int err = -EINVAL;
1436
1437 if (size != sizeof(outarg))
1438 goto err;
1439
1440 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1441 if (err)
1442 goto err;
1443 fuse_copy_finish(cs);
1444
1445 down_read(&fc->killsb);
1446 err = fuse_reverse_inval_inode(fc, outarg.ino,
1447 outarg.off, outarg.len);
1448 up_read(&fc->killsb);
1449 return err;
1450
1451err:
1452 fuse_copy_finish(cs);
1453 return err;
1454}
1455
1456static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1457 struct fuse_copy_state *cs)
1458{
1459 struct fuse_notify_inval_entry_out outarg;
1460 int err = -ENOMEM;
1461 char *buf;
1462 struct qstr name;
1463
1464 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1465 if (!buf)
1466 goto err;
1467
1468 err = -EINVAL;
1469 if (size < sizeof(outarg))
1470 goto err;
1471
1472 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1473 if (err)
1474 goto err;
1475
1476 err = -ENAMETOOLONG;
1477 if (outarg.namelen > FUSE_NAME_MAX)
1478 goto err;
1479
1480 err = -EINVAL;
1481 if (size != sizeof(outarg) + outarg.namelen + 1)
1482 goto err;
1483
1484 name.name = buf;
1485 name.len = outarg.namelen;
1486 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1487 if (err)
1488 goto err;
1489 fuse_copy_finish(cs);
1490 buf[outarg.namelen] = 0;
1491
1492 down_read(&fc->killsb);
1493 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name);
1494 up_read(&fc->killsb);
1495 kfree(buf);
1496 return err;
1497
1498err:
1499 kfree(buf);
1500 fuse_copy_finish(cs);
1501 return err;
1502}
1503
1504static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1505 struct fuse_copy_state *cs)
1506{
1507 struct fuse_notify_delete_out outarg;
1508 int err = -ENOMEM;
1509 char *buf;
1510 struct qstr name;
1511
1512 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1513 if (!buf)
1514 goto err;
1515
1516 err = -EINVAL;
1517 if (size < sizeof(outarg))
1518 goto err;
1519
1520 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1521 if (err)
1522 goto err;
1523
1524 err = -ENAMETOOLONG;
1525 if (outarg.namelen > FUSE_NAME_MAX)
1526 goto err;
1527
1528 err = -EINVAL;
1529 if (size != sizeof(outarg) + outarg.namelen + 1)
1530 goto err;
1531
1532 name.name = buf;
1533 name.len = outarg.namelen;
1534 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1535 if (err)
1536 goto err;
1537 fuse_copy_finish(cs);
1538 buf[outarg.namelen] = 0;
1539
1540 down_read(&fc->killsb);
1541 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name);
1542 up_read(&fc->killsb);
1543 kfree(buf);
1544 return err;
1545
1546err:
1547 kfree(buf);
1548 fuse_copy_finish(cs);
1549 return err;
1550}
1551
1552static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1553 struct fuse_copy_state *cs)
1554{
1555 struct fuse_notify_store_out outarg;
1556 struct inode *inode;
1557 struct address_space *mapping;
1558 u64 nodeid;
1559 int err;
1560 pgoff_t index;
1561 unsigned int offset;
1562 unsigned int num;
1563 loff_t file_size;
1564 loff_t end;
1565
1566 err = -EINVAL;
1567 if (size < sizeof(outarg))
1568 goto out_finish;
1569
1570 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1571 if (err)
1572 goto out_finish;
1573
1574 err = -EINVAL;
1575 if (size - sizeof(outarg) != outarg.size)
1576 goto out_finish;
1577
1578 nodeid = outarg.nodeid;
1579
1580 down_read(&fc->killsb);
1581
1582 err = -ENOENT;
1583 inode = fuse_ilookup(fc, nodeid, NULL);
1584 if (!inode)
1585 goto out_up_killsb;
1586
1587 mapping = inode->i_mapping;
1588 index = outarg.offset >> PAGE_SHIFT;
1589 offset = outarg.offset & ~PAGE_MASK;
1590 file_size = i_size_read(inode);
1591 end = outarg.offset + outarg.size;
1592 if (end > file_size) {
1593 file_size = end;
1594 fuse_write_update_size(inode, file_size);
1595 }
1596
1597 num = outarg.size;
1598 while (num) {
1599 struct page *page;
1600 unsigned int this_num;
1601
1602 err = -ENOMEM;
1603 page = find_or_create_page(mapping, index,
1604 mapping_gfp_mask(mapping));
1605 if (!page)
1606 goto out_iput;
1607
1608 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1609 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1610 if (!err && offset == 0 &&
1611 (this_num == PAGE_SIZE || file_size == end))
1612 SetPageUptodate(page);
1613 unlock_page(page);
1614 put_page(page);
1615
1616 if (err)
1617 goto out_iput;
1618
1619 num -= this_num;
1620 offset = 0;
1621 index++;
1622 }
1623
1624 err = 0;
1625
1626out_iput:
1627 iput(inode);
1628out_up_killsb:
1629 up_read(&fc->killsb);
1630out_finish:
1631 fuse_copy_finish(cs);
1632 return err;
1633}
1634
1635struct fuse_retrieve_args {
1636 struct fuse_args_pages ap;
1637 struct fuse_notify_retrieve_in inarg;
1638};
1639
1640static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1641 int error)
1642{
1643 struct fuse_retrieve_args *ra =
1644 container_of(args, typeof(*ra), ap.args);
1645
1646 release_pages(ra->ap.pages, ra->ap.num_pages);
1647 kfree(ra);
1648}
1649
1650static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1651 struct fuse_notify_retrieve_out *outarg)
1652{
1653 int err;
1654 struct address_space *mapping = inode->i_mapping;
1655 pgoff_t index;
1656 loff_t file_size;
1657 unsigned int num;
1658 unsigned int offset;
1659 size_t total_len = 0;
1660 unsigned int num_pages;
1661 struct fuse_conn *fc = fm->fc;
1662 struct fuse_retrieve_args *ra;
1663 size_t args_size = sizeof(*ra);
1664 struct fuse_args_pages *ap;
1665 struct fuse_args *args;
1666
1667 offset = outarg->offset & ~PAGE_MASK;
1668 file_size = i_size_read(inode);
1669
1670 num = min(outarg->size, fc->max_write);
1671 if (outarg->offset > file_size)
1672 num = 0;
1673 else if (outarg->offset + num > file_size)
1674 num = file_size - outarg->offset;
1675
1676 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1677 num_pages = min(num_pages, fc->max_pages);
1678
1679 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1680
1681 ra = kzalloc(args_size, GFP_KERNEL);
1682 if (!ra)
1683 return -ENOMEM;
1684
1685 ap = &ra->ap;
1686 ap->pages = (void *) (ra + 1);
1687 ap->descs = (void *) (ap->pages + num_pages);
1688
1689 args = &ap->args;
1690 args->nodeid = outarg->nodeid;
1691 args->opcode = FUSE_NOTIFY_REPLY;
1692 args->in_numargs = 2;
1693 args->in_pages = true;
1694 args->end = fuse_retrieve_end;
1695
1696 index = outarg->offset >> PAGE_SHIFT;
1697
1698 while (num && ap->num_pages < num_pages) {
1699 struct page *page;
1700 unsigned int this_num;
1701
1702 page = find_get_page(mapping, index);
1703 if (!page)
1704 break;
1705
1706 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1707 ap->pages[ap->num_pages] = page;
1708 ap->descs[ap->num_pages].offset = offset;
1709 ap->descs[ap->num_pages].length = this_num;
1710 ap->num_pages++;
1711
1712 offset = 0;
1713 num -= this_num;
1714 total_len += this_num;
1715 index++;
1716 }
1717 ra->inarg.offset = outarg->offset;
1718 ra->inarg.size = total_len;
1719 args->in_args[0].size = sizeof(ra->inarg);
1720 args->in_args[0].value = &ra->inarg;
1721 args->in_args[1].size = total_len;
1722
1723 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1724 if (err)
1725 fuse_retrieve_end(fm, args, err);
1726
1727 return err;
1728}
1729
1730static 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 fuse_mount *fm;
1735 struct inode *inode;
1736 u64 nodeid;
1737 int err;
1738
1739 err = -EINVAL;
1740 if (size != sizeof(outarg))
1741 goto copy_finish;
1742
1743 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1744 if (err)
1745 goto copy_finish;
1746
1747 fuse_copy_finish(cs);
1748
1749 down_read(&fc->killsb);
1750 err = -ENOENT;
1751 nodeid = outarg.nodeid;
1752
1753 inode = fuse_ilookup(fc, nodeid, &fm);
1754 if (inode) {
1755 err = fuse_retrieve(fm, inode, &outarg);
1756 iput(inode);
1757 }
1758 up_read(&fc->killsb);
1759
1760 return err;
1761
1762copy_finish:
1763 fuse_copy_finish(cs);
1764 return err;
1765}
1766
1767static 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 */
1799static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1800{
1801 unsigned int hash = fuse_req_hash(unique);
1802 struct fuse_req *req;
1803
1804 list_for_each_entry(req, &fpq->processing[hash], list) {
1805 if (req->in.h.unique == unique)
1806 return req;
1807 }
1808 return NULL;
1809}
1810
1811static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1812 unsigned nbytes)
1813{
1814 unsigned reqsize = sizeof(struct fuse_out_header);
1815
1816 reqsize += fuse_len_args(args->out_numargs, args->out_args);
1817
1818 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1819 return -EINVAL;
1820 else if (reqsize > nbytes) {
1821 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1822 unsigned diffsize = reqsize - nbytes;
1823
1824 if (diffsize > lastarg->size)
1825 return -EINVAL;
1826 lastarg->size -= diffsize;
1827 }
1828 return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1829 args->out_args, args->page_zeroing);
1830}
1831
1832/*
1833 * Write a single reply to a request. First the header is copied from
1834 * the write buffer. The request is then searched on the processing
1835 * list by the unique ID found in the header. If found, then remove
1836 * it from the list and copy the rest of the buffer to the request.
1837 * The request is finished by calling fuse_request_end().
1838 */
1839static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1840 struct fuse_copy_state *cs, size_t nbytes)
1841{
1842 int err;
1843 struct fuse_conn *fc = fud->fc;
1844 struct fuse_pqueue *fpq = &fud->pq;
1845 struct fuse_req *req;
1846 struct fuse_out_header oh;
1847
1848 err = -EINVAL;
1849 if (nbytes < sizeof(struct fuse_out_header))
1850 goto out;
1851
1852 err = fuse_copy_one(cs, &oh, sizeof(oh));
1853 if (err)
1854 goto copy_finish;
1855
1856 err = -EINVAL;
1857 if (oh.len != nbytes)
1858 goto copy_finish;
1859
1860 /*
1861 * Zero oh.unique indicates unsolicited notification message
1862 * and error contains notification code.
1863 */
1864 if (!oh.unique) {
1865 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1866 goto out;
1867 }
1868
1869 err = -EINVAL;
1870 if (oh.error <= -512 || oh.error > 0)
1871 goto copy_finish;
1872
1873 spin_lock(&fpq->lock);
1874 req = NULL;
1875 if (fpq->connected)
1876 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1877
1878 err = -ENOENT;
1879 if (!req) {
1880 spin_unlock(&fpq->lock);
1881 goto copy_finish;
1882 }
1883
1884 /* Is it an interrupt reply ID? */
1885 if (oh.unique & FUSE_INT_REQ_BIT) {
1886 __fuse_get_request(req);
1887 spin_unlock(&fpq->lock);
1888
1889 err = 0;
1890 if (nbytes != sizeof(struct fuse_out_header))
1891 err = -EINVAL;
1892 else if (oh.error == -ENOSYS)
1893 fc->no_interrupt = 1;
1894 else if (oh.error == -EAGAIN)
1895 err = queue_interrupt(req);
1896
1897 fuse_put_request(req);
1898
1899 goto copy_finish;
1900 }
1901
1902 clear_bit(FR_SENT, &req->flags);
1903 list_move(&req->list, &fpq->io);
1904 req->out.h = oh;
1905 set_bit(FR_LOCKED, &req->flags);
1906 spin_unlock(&fpq->lock);
1907 cs->req = req;
1908 if (!req->args->page_replace)
1909 cs->move_pages = 0;
1910
1911 if (oh.error)
1912 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1913 else
1914 err = copy_out_args(cs, req->args, nbytes);
1915 fuse_copy_finish(cs);
1916
1917 spin_lock(&fpq->lock);
1918 clear_bit(FR_LOCKED, &req->flags);
1919 if (!fpq->connected)
1920 err = -ENOENT;
1921 else if (err)
1922 req->out.h.error = -EIO;
1923 if (!test_bit(FR_PRIVATE, &req->flags))
1924 list_del_init(&req->list);
1925 spin_unlock(&fpq->lock);
1926
1927 fuse_request_end(req);
1928out:
1929 return err ? err : nbytes;
1930
1931copy_finish:
1932 fuse_copy_finish(cs);
1933 goto out;
1934}
1935
1936static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1937{
1938 struct fuse_copy_state cs;
1939 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1940
1941 if (!fud)
1942 return -EPERM;
1943
1944 if (!iter_is_iovec(from))
1945 return -EINVAL;
1946
1947 fuse_copy_init(&cs, 0, from);
1948
1949 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1950}
1951
1952static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1953 struct file *out, loff_t *ppos,
1954 size_t len, unsigned int flags)
1955{
1956 unsigned int head, tail, mask, count;
1957 unsigned nbuf;
1958 unsigned idx;
1959 struct pipe_buffer *bufs;
1960 struct fuse_copy_state cs;
1961 struct fuse_dev *fud;
1962 size_t rem;
1963 ssize_t ret;
1964
1965 fud = fuse_get_dev(out);
1966 if (!fud)
1967 return -EPERM;
1968
1969 pipe_lock(pipe);
1970
1971 head = pipe->head;
1972 tail = pipe->tail;
1973 mask = pipe->ring_size - 1;
1974 count = head - tail;
1975
1976 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1977 if (!bufs) {
1978 pipe_unlock(pipe);
1979 return -ENOMEM;
1980 }
1981
1982 nbuf = 0;
1983 rem = 0;
1984 for (idx = tail; idx != head && rem < len; idx++)
1985 rem += pipe->bufs[idx & mask].len;
1986
1987 ret = -EINVAL;
1988 if (rem < len)
1989 goto out_free;
1990
1991 rem = len;
1992 while (rem) {
1993 struct pipe_buffer *ibuf;
1994 struct pipe_buffer *obuf;
1995
1996 if (WARN_ON(nbuf >= count || tail == head))
1997 goto out_free;
1998
1999 ibuf = &pipe->bufs[tail & mask];
2000 obuf = &bufs[nbuf];
2001
2002 if (rem >= ibuf->len) {
2003 *obuf = *ibuf;
2004 ibuf->ops = NULL;
2005 tail++;
2006 pipe->tail = tail;
2007 } else {
2008 if (!pipe_buf_get(pipe, ibuf))
2009 goto out_free;
2010
2011 *obuf = *ibuf;
2012 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2013 obuf->len = rem;
2014 ibuf->offset += obuf->len;
2015 ibuf->len -= obuf->len;
2016 }
2017 nbuf++;
2018 rem -= obuf->len;
2019 }
2020 pipe_unlock(pipe);
2021
2022 fuse_copy_init(&cs, 0, NULL);
2023 cs.pipebufs = bufs;
2024 cs.nr_segs = nbuf;
2025 cs.pipe = pipe;
2026
2027 if (flags & SPLICE_F_MOVE)
2028 cs.move_pages = 1;
2029
2030 ret = fuse_dev_do_write(fud, &cs, len);
2031
2032 pipe_lock(pipe);
2033out_free:
2034 for (idx = 0; idx < nbuf; idx++)
2035 pipe_buf_release(pipe, &bufs[idx]);
2036 pipe_unlock(pipe);
2037
2038 kvfree(bufs);
2039 return ret;
2040}
2041
2042static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2043{
2044 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2045 struct fuse_iqueue *fiq;
2046 struct fuse_dev *fud = fuse_get_dev(file);
2047
2048 if (!fud)
2049 return EPOLLERR;
2050
2051 fiq = &fud->fc->iq;
2052 poll_wait(file, &fiq->waitq, wait);
2053
2054 spin_lock(&fiq->lock);
2055 if (!fiq->connected)
2056 mask = EPOLLERR;
2057 else if (request_pending(fiq))
2058 mask |= EPOLLIN | EPOLLRDNORM;
2059 spin_unlock(&fiq->lock);
2060
2061 return mask;
2062}
2063
2064/* Abort all requests on the given list (pending or processing) */
2065static void end_requests(struct list_head *head)
2066{
2067 while (!list_empty(head)) {
2068 struct fuse_req *req;
2069 req = list_entry(head->next, struct fuse_req, list);
2070 req->out.h.error = -ECONNABORTED;
2071 clear_bit(FR_SENT, &req->flags);
2072 list_del_init(&req->list);
2073 fuse_request_end(req);
2074 }
2075}
2076
2077static void end_polls(struct fuse_conn *fc)
2078{
2079 struct rb_node *p;
2080
2081 p = rb_first(&fc->polled_files);
2082
2083 while (p) {
2084 struct fuse_file *ff;
2085 ff = rb_entry(p, struct fuse_file, polled_node);
2086 wake_up_interruptible_all(&ff->poll_wait);
2087
2088 p = rb_next(p);
2089 }
2090}
2091
2092/*
2093 * Abort all requests.
2094 *
2095 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2096 * filesystem.
2097 *
2098 * The same effect is usually achievable through killing the filesystem daemon
2099 * and all users of the filesystem. The exception is the combination of an
2100 * asynchronous request and the tricky deadlock (see
2101 * Documentation/filesystems/fuse.rst).
2102 *
2103 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2104 * requests, they should be finished off immediately. Locked requests will be
2105 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2106 * requests. It is possible that some request will finish before we can. This
2107 * is OK, the request will in that case be removed from the list before we touch
2108 * it.
2109 */
2110void fuse_abort_conn(struct fuse_conn *fc)
2111{
2112 struct fuse_iqueue *fiq = &fc->iq;
2113
2114 spin_lock(&fc->lock);
2115 if (fc->connected) {
2116 struct fuse_dev *fud;
2117 struct fuse_req *req, *next;
2118 LIST_HEAD(to_end);
2119 unsigned int i;
2120
2121 /* Background queuing checks fc->connected under bg_lock */
2122 spin_lock(&fc->bg_lock);
2123 fc->connected = 0;
2124 spin_unlock(&fc->bg_lock);
2125
2126 fuse_set_initialized(fc);
2127 list_for_each_entry(fud, &fc->devices, entry) {
2128 struct fuse_pqueue *fpq = &fud->pq;
2129
2130 spin_lock(&fpq->lock);
2131 fpq->connected = 0;
2132 list_for_each_entry_safe(req, next, &fpq->io, list) {
2133 req->out.h.error = -ECONNABORTED;
2134 spin_lock(&req->waitq.lock);
2135 set_bit(FR_ABORTED, &req->flags);
2136 if (!test_bit(FR_LOCKED, &req->flags)) {
2137 set_bit(FR_PRIVATE, &req->flags);
2138 __fuse_get_request(req);
2139 list_move(&req->list, &to_end);
2140 }
2141 spin_unlock(&req->waitq.lock);
2142 }
2143 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2144 list_splice_tail_init(&fpq->processing[i],
2145 &to_end);
2146 spin_unlock(&fpq->lock);
2147 }
2148 spin_lock(&fc->bg_lock);
2149 fc->blocked = 0;
2150 fc->max_background = UINT_MAX;
2151 flush_bg_queue(fc);
2152 spin_unlock(&fc->bg_lock);
2153
2154 spin_lock(&fiq->lock);
2155 fiq->connected = 0;
2156 list_for_each_entry(req, &fiq->pending, list)
2157 clear_bit(FR_PENDING, &req->flags);
2158 list_splice_tail_init(&fiq->pending, &to_end);
2159 while (forget_pending(fiq))
2160 kfree(fuse_dequeue_forget(fiq, 1, NULL));
2161 wake_up_all(&fiq->waitq);
2162 spin_unlock(&fiq->lock);
2163 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2164 end_polls(fc);
2165 wake_up_all(&fc->blocked_waitq);
2166 spin_unlock(&fc->lock);
2167
2168 end_requests(&to_end);
2169 } else {
2170 spin_unlock(&fc->lock);
2171 }
2172}
2173EXPORT_SYMBOL_GPL(fuse_abort_conn);
2174
2175void fuse_wait_aborted(struct fuse_conn *fc)
2176{
2177 /* matches implicit memory barrier in fuse_drop_waiting() */
2178 smp_mb();
2179 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2180}
2181
2182int fuse_dev_release(struct inode *inode, struct file *file)
2183{
2184 struct fuse_dev *fud = fuse_get_dev(file);
2185
2186 if (fud) {
2187 struct fuse_conn *fc = fud->fc;
2188 struct fuse_pqueue *fpq = &fud->pq;
2189 LIST_HEAD(to_end);
2190 unsigned int i;
2191
2192 spin_lock(&fpq->lock);
2193 WARN_ON(!list_empty(&fpq->io));
2194 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2195 list_splice_init(&fpq->processing[i], &to_end);
2196 spin_unlock(&fpq->lock);
2197
2198 end_requests(&to_end);
2199
2200 /* Are we the last open device? */
2201 if (atomic_dec_and_test(&fc->dev_count)) {
2202 WARN_ON(fc->iq.fasync != NULL);
2203 fuse_abort_conn(fc);
2204 }
2205 fuse_dev_free(fud);
2206 }
2207 return 0;
2208}
2209EXPORT_SYMBOL_GPL(fuse_dev_release);
2210
2211static int fuse_dev_fasync(int fd, struct file *file, int on)
2212{
2213 struct fuse_dev *fud = fuse_get_dev(file);
2214
2215 if (!fud)
2216 return -EPERM;
2217
2218 /* No locking - fasync_helper does its own locking */
2219 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2220}
2221
2222static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2223{
2224 struct fuse_dev *fud;
2225
2226 if (new->private_data)
2227 return -EINVAL;
2228
2229 fud = fuse_dev_alloc_install(fc);
2230 if (!fud)
2231 return -ENOMEM;
2232
2233 new->private_data = fud;
2234 atomic_inc(&fc->dev_count);
2235
2236 return 0;
2237}
2238
2239static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2240 unsigned long arg)
2241{
2242 int res;
2243 int oldfd;
2244 struct fuse_dev *fud = NULL;
2245
2246 switch (cmd) {
2247 case FUSE_DEV_IOC_CLONE:
2248 res = -EFAULT;
2249 if (!get_user(oldfd, (__u32 __user *)arg)) {
2250 struct file *old = fget(oldfd);
2251
2252 res = -EINVAL;
2253 if (old) {
2254 /*
2255 * Check against file->f_op because CUSE
2256 * uses the same ioctl handler.
2257 */
2258 if (old->f_op == file->f_op &&
2259 old->f_cred->user_ns == file->f_cred->user_ns)
2260 fud = fuse_get_dev(old);
2261
2262 if (fud) {
2263 mutex_lock(&fuse_mutex);
2264 res = fuse_device_clone(fud->fc, file);
2265 mutex_unlock(&fuse_mutex);
2266 }
2267 fput(old);
2268 }
2269 }
2270 break;
2271 default:
2272 res = -ENOTTY;
2273 break;
2274 }
2275 return res;
2276}
2277
2278const struct file_operations fuse_dev_operations = {
2279 .owner = THIS_MODULE,
2280 .open = fuse_dev_open,
2281 .llseek = no_llseek,
2282 .read_iter = fuse_dev_read,
2283 .splice_read = fuse_dev_splice_read,
2284 .write_iter = fuse_dev_write,
2285 .splice_write = fuse_dev_splice_write,
2286 .poll = fuse_dev_poll,
2287 .release = fuse_dev_release,
2288 .fasync = fuse_dev_fasync,
2289 .unlocked_ioctl = fuse_dev_ioctl,
2290 .compat_ioctl = compat_ptr_ioctl,
2291};
2292EXPORT_SYMBOL_GPL(fuse_dev_operations);
2293
2294static struct miscdevice fuse_miscdevice = {
2295 .minor = FUSE_MINOR,
2296 .name = "fuse",
2297 .fops = &fuse_dev_operations,
2298};
2299
2300int __init fuse_dev_init(void)
2301{
2302 int err = -ENOMEM;
2303 fuse_req_cachep = kmem_cache_create("fuse_request",
2304 sizeof(struct fuse_req),
2305 0, 0, NULL);
2306 if (!fuse_req_cachep)
2307 goto out;
2308
2309 err = misc_register(&fuse_miscdevice);
2310 if (err)
2311 goto out_cache_clean;
2312
2313 return 0;
2314
2315 out_cache_clean:
2316 kmem_cache_destroy(fuse_req_cachep);
2317 out:
2318 return err;
2319}
2320
2321void fuse_dev_cleanup(void)
2322{
2323 misc_deregister(&fuse_miscdevice);
2324 kmem_cache_destroy(fuse_req_cachep);
2325}