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Merge tag 'rtc-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
[mirror_ubuntu-jammy-kernel.git] / fs / fuse / dev.c
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/sched/signal.h>
15 #include <linux/uio.h>
16 #include <linux/miscdevice.h>
17 #include <linux/pagemap.h>
18 #include <linux/file.h>
19 #include <linux/slab.h>
20 #include <linux/pipe_fs_i.h>
21 #include <linux/swap.h>
22 #include <linux/splice.h>
23 #include <linux/sched.h>
24
25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26 MODULE_ALIAS("devname:fuse");
27
28 /* 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
32 static struct kmem_cache *fuse_req_cachep;
33
34 static 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
43 static 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
53 static 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
62 static void fuse_request_free(struct fuse_req *req)
63 {
64 kmem_cache_free(fuse_req_cachep, req);
65 }
66
67 static void __fuse_get_request(struct fuse_req *req)
68 {
69 refcount_inc(&req->count);
70 }
71
72 /* Must be called with > 1 refcount */
73 static void __fuse_put_request(struct fuse_req *req)
74 {
75 refcount_dec(&req->count);
76 }
77
78 void 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
85 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
86 {
87 return !fc->initialized || (for_background && fc->blocked);
88 }
89
90 static void fuse_drop_waiting(struct fuse_conn *fc)
91 {
92 /*
93 * lockess check of fc->connected is okay, because atomic_dec_and_test()
94 * provides a memory barrier mached with the one in fuse_wait_aborted()
95 * to ensure no wake-up is missed.
96 */
97 if (atomic_dec_and_test(&fc->num_waiting) &&
98 !READ_ONCE(fc->connected)) {
99 /* wake up aborters */
100 wake_up_all(&fc->blocked_waitq);
101 }
102 }
103
104 static void fuse_put_request(struct fuse_req *req);
105
106 static 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
158 static 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
183 unsigned 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 }
193 EXPORT_SYMBOL_GPL(fuse_len_args);
194
195 u64 fuse_get_unique(struct fuse_iqueue *fiq)
196 {
197 fiq->reqctr += FUSE_REQ_ID_STEP;
198 return fiq->reqctr;
199 }
200 EXPORT_SYMBOL_GPL(fuse_get_unique);
201
202 static 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 */
210 static 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
218 const 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 };
223 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
224
225 static 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
236 void 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
255 static 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 */
280 void fuse_request_end(struct fuse_req *req)
281 {
282 struct fuse_mount *fm = req->fm;
283 struct fuse_conn *fc = fm->fc;
284 struct fuse_iqueue *fiq = &fc->iq;
285
286 if (test_and_set_bit(FR_FINISHED, &req->flags))
287 goto put_request;
288
289 /*
290 * test_and_set_bit() implies smp_mb() between bit
291 * changing and below intr_entry check. Pairs with
292 * smp_mb() from queue_interrupt().
293 */
294 if (!list_empty(&req->intr_entry)) {
295 spin_lock(&fiq->lock);
296 list_del_init(&req->intr_entry);
297 spin_unlock(&fiq->lock);
298 }
299 WARN_ON(test_bit(FR_PENDING, &req->flags));
300 WARN_ON(test_bit(FR_SENT, &req->flags));
301 if (test_bit(FR_BACKGROUND, &req->flags)) {
302 spin_lock(&fc->bg_lock);
303 clear_bit(FR_BACKGROUND, &req->flags);
304 if (fc->num_background == fc->max_background) {
305 fc->blocked = 0;
306 wake_up(&fc->blocked_waitq);
307 } else if (!fc->blocked) {
308 /*
309 * Wake up next waiter, if any. It's okay to use
310 * waitqueue_active(), as we've already synced up
311 * fc->blocked with waiters with the wake_up() call
312 * above.
313 */
314 if (waitqueue_active(&fc->blocked_waitq))
315 wake_up(&fc->blocked_waitq);
316 }
317
318 if (fc->num_background == fc->congestion_threshold && fm->sb) {
319 clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
320 clear_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC);
321 }
322 fc->num_background--;
323 fc->active_background--;
324 flush_bg_queue(fc);
325 spin_unlock(&fc->bg_lock);
326 } else {
327 /* Wake up waiter sleeping in request_wait_answer() */
328 wake_up(&req->waitq);
329 }
330
331 if (test_bit(FR_ASYNC, &req->flags))
332 req->args->end(fm, req->args, req->out.h.error);
333 put_request:
334 fuse_put_request(req);
335 }
336 EXPORT_SYMBOL_GPL(fuse_request_end);
337
338 static 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
368 static 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
414 static 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
436 static 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
469 static 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
478 static 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
487 ssize_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
526 static 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
556 int 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 }
583 EXPORT_SYMBOL_GPL(fuse_simple_background);
584
585 static 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 */
618 static 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 */
636 static 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
650 struct 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
664 static 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 */
673 static 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 */
695 static 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 */
755 static 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
776 static int fuse_check_page(struct page *page)
777 {
778 if (page_mapcount(page) ||
779 page->mapping != NULL ||
780 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
781 ~(1 << PG_locked |
782 1 << PG_referenced |
783 1 << PG_uptodate |
784 1 << PG_lru |
785 1 << PG_active |
786 1 << PG_reclaim |
787 1 << PG_waiters))) {
788 dump_page(page, "fuse: trying to steal weird page");
789 return 1;
790 }
791 return 0;
792 }
793
794 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
795 {
796 int err;
797 struct page *oldpage = *pagep;
798 struct page *newpage;
799 struct pipe_buffer *buf = cs->pipebufs;
800
801 get_page(oldpage);
802 err = unlock_request(cs->req);
803 if (err)
804 goto out_put_old;
805
806 fuse_copy_finish(cs);
807
808 err = pipe_buf_confirm(cs->pipe, buf);
809 if (err)
810 goto out_put_old;
811
812 BUG_ON(!cs->nr_segs);
813 cs->currbuf = buf;
814 cs->len = buf->len;
815 cs->pipebufs++;
816 cs->nr_segs--;
817
818 if (cs->len != PAGE_SIZE)
819 goto out_fallback;
820
821 if (!pipe_buf_try_steal(cs->pipe, buf))
822 goto out_fallback;
823
824 newpage = buf->page;
825
826 if (!PageUptodate(newpage))
827 SetPageUptodate(newpage);
828
829 ClearPageMappedToDisk(newpage);
830
831 if (fuse_check_page(newpage) != 0)
832 goto out_fallback_unlock;
833
834 /*
835 * This is a new and locked page, it shouldn't be mapped or
836 * have any special flags on it
837 */
838 if (WARN_ON(page_mapped(oldpage)))
839 goto out_fallback_unlock;
840 if (WARN_ON(page_has_private(oldpage)))
841 goto out_fallback_unlock;
842 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
843 goto out_fallback_unlock;
844 if (WARN_ON(PageMlocked(oldpage)))
845 goto out_fallback_unlock;
846
847 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
848 if (err) {
849 unlock_page(newpage);
850 goto out_put_old;
851 }
852
853 get_page(newpage);
854
855 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
856 lru_cache_add(newpage);
857
858 err = 0;
859 spin_lock(&cs->req->waitq.lock);
860 if (test_bit(FR_ABORTED, &cs->req->flags))
861 err = -ENOENT;
862 else
863 *pagep = newpage;
864 spin_unlock(&cs->req->waitq.lock);
865
866 if (err) {
867 unlock_page(newpage);
868 put_page(newpage);
869 goto out_put_old;
870 }
871
872 unlock_page(oldpage);
873 /* Drop ref for ap->pages[] array */
874 put_page(oldpage);
875 cs->len = 0;
876
877 err = 0;
878 out_put_old:
879 /* Drop ref obtained in this function */
880 put_page(oldpage);
881 return err;
882
883 out_fallback_unlock:
884 unlock_page(newpage);
885 out_fallback:
886 cs->pg = buf->page;
887 cs->offset = buf->offset;
888
889 err = lock_request(cs->req);
890 if (!err)
891 err = 1;
892
893 goto out_put_old;
894 }
895
896 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
897 unsigned offset, unsigned count)
898 {
899 struct pipe_buffer *buf;
900 int err;
901
902 if (cs->nr_segs >= cs->pipe->max_usage)
903 return -EIO;
904
905 get_page(page);
906 err = unlock_request(cs->req);
907 if (err) {
908 put_page(page);
909 return err;
910 }
911
912 fuse_copy_finish(cs);
913
914 buf = cs->pipebufs;
915 buf->page = page;
916 buf->offset = offset;
917 buf->len = count;
918
919 cs->pipebufs++;
920 cs->nr_segs++;
921 cs->len = 0;
922
923 return 0;
924 }
925
926 /*
927 * Copy a page in the request to/from the userspace buffer. Must be
928 * done atomically
929 */
930 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
931 unsigned offset, unsigned count, int zeroing)
932 {
933 int err;
934 struct page *page = *pagep;
935
936 if (page && zeroing && count < PAGE_SIZE)
937 clear_highpage(page);
938
939 while (count) {
940 if (cs->write && cs->pipebufs && page) {
941 return fuse_ref_page(cs, page, offset, count);
942 } else if (!cs->len) {
943 if (cs->move_pages && page &&
944 offset == 0 && count == PAGE_SIZE) {
945 err = fuse_try_move_page(cs, pagep);
946 if (err <= 0)
947 return err;
948 } else {
949 err = fuse_copy_fill(cs);
950 if (err)
951 return err;
952 }
953 }
954 if (page) {
955 void *mapaddr = kmap_atomic(page);
956 void *buf = mapaddr + offset;
957 offset += fuse_copy_do(cs, &buf, &count);
958 kunmap_atomic(mapaddr);
959 } else
960 offset += fuse_copy_do(cs, NULL, &count);
961 }
962 if (page && !cs->write)
963 flush_dcache_page(page);
964 return 0;
965 }
966
967 /* Copy pages in the request to/from userspace buffer */
968 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
969 int zeroing)
970 {
971 unsigned i;
972 struct fuse_req *req = cs->req;
973 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
974
975
976 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
977 int err;
978 unsigned int offset = ap->descs[i].offset;
979 unsigned int count = min(nbytes, ap->descs[i].length);
980
981 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
982 if (err)
983 return err;
984
985 nbytes -= count;
986 }
987 return 0;
988 }
989
990 /* Copy a single argument in the request to/from userspace buffer */
991 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
992 {
993 while (size) {
994 if (!cs->len) {
995 int err = fuse_copy_fill(cs);
996 if (err)
997 return err;
998 }
999 fuse_copy_do(cs, &val, &size);
1000 }
1001 return 0;
1002 }
1003
1004 /* Copy request arguments to/from userspace buffer */
1005 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1006 unsigned argpages, struct fuse_arg *args,
1007 int zeroing)
1008 {
1009 int err = 0;
1010 unsigned i;
1011
1012 for (i = 0; !err && i < numargs; i++) {
1013 struct fuse_arg *arg = &args[i];
1014 if (i == numargs - 1 && argpages)
1015 err = fuse_copy_pages(cs, arg->size, zeroing);
1016 else
1017 err = fuse_copy_one(cs, arg->value, arg->size);
1018 }
1019 return err;
1020 }
1021
1022 static int forget_pending(struct fuse_iqueue *fiq)
1023 {
1024 return fiq->forget_list_head.next != NULL;
1025 }
1026
1027 static int request_pending(struct fuse_iqueue *fiq)
1028 {
1029 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1030 forget_pending(fiq);
1031 }
1032
1033 /*
1034 * Transfer an interrupt request to userspace
1035 *
1036 * Unlike other requests this is assembled on demand, without a need
1037 * to allocate a separate fuse_req structure.
1038 *
1039 * Called with fiq->lock held, releases it
1040 */
1041 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1042 struct fuse_copy_state *cs,
1043 size_t nbytes, struct fuse_req *req)
1044 __releases(fiq->lock)
1045 {
1046 struct fuse_in_header ih;
1047 struct fuse_interrupt_in arg;
1048 unsigned reqsize = sizeof(ih) + sizeof(arg);
1049 int err;
1050
1051 list_del_init(&req->intr_entry);
1052 memset(&ih, 0, sizeof(ih));
1053 memset(&arg, 0, sizeof(arg));
1054 ih.len = reqsize;
1055 ih.opcode = FUSE_INTERRUPT;
1056 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1057 arg.unique = req->in.h.unique;
1058
1059 spin_unlock(&fiq->lock);
1060 if (nbytes < reqsize)
1061 return -EINVAL;
1062
1063 err = fuse_copy_one(cs, &ih, sizeof(ih));
1064 if (!err)
1065 err = fuse_copy_one(cs, &arg, sizeof(arg));
1066 fuse_copy_finish(cs);
1067
1068 return err ? err : reqsize;
1069 }
1070
1071 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1072 unsigned int max,
1073 unsigned int *countp)
1074 {
1075 struct fuse_forget_link *head = fiq->forget_list_head.next;
1076 struct fuse_forget_link **newhead = &head;
1077 unsigned count;
1078
1079 for (count = 0; *newhead != NULL && count < max; count++)
1080 newhead = &(*newhead)->next;
1081
1082 fiq->forget_list_head.next = *newhead;
1083 *newhead = NULL;
1084 if (fiq->forget_list_head.next == NULL)
1085 fiq->forget_list_tail = &fiq->forget_list_head;
1086
1087 if (countp != NULL)
1088 *countp = count;
1089
1090 return head;
1091 }
1092 EXPORT_SYMBOL(fuse_dequeue_forget);
1093
1094 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1095 struct fuse_copy_state *cs,
1096 size_t nbytes)
1097 __releases(fiq->lock)
1098 {
1099 int err;
1100 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1101 struct fuse_forget_in arg = {
1102 .nlookup = forget->forget_one.nlookup,
1103 };
1104 struct fuse_in_header ih = {
1105 .opcode = FUSE_FORGET,
1106 .nodeid = forget->forget_one.nodeid,
1107 .unique = fuse_get_unique(fiq),
1108 .len = sizeof(ih) + sizeof(arg),
1109 };
1110
1111 spin_unlock(&fiq->lock);
1112 kfree(forget);
1113 if (nbytes < ih.len)
1114 return -EINVAL;
1115
1116 err = fuse_copy_one(cs, &ih, sizeof(ih));
1117 if (!err)
1118 err = fuse_copy_one(cs, &arg, sizeof(arg));
1119 fuse_copy_finish(cs);
1120
1121 if (err)
1122 return err;
1123
1124 return ih.len;
1125 }
1126
1127 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1128 struct fuse_copy_state *cs, size_t nbytes)
1129 __releases(fiq->lock)
1130 {
1131 int err;
1132 unsigned max_forgets;
1133 unsigned count;
1134 struct fuse_forget_link *head;
1135 struct fuse_batch_forget_in arg = { .count = 0 };
1136 struct fuse_in_header ih = {
1137 .opcode = FUSE_BATCH_FORGET,
1138 .unique = fuse_get_unique(fiq),
1139 .len = sizeof(ih) + sizeof(arg),
1140 };
1141
1142 if (nbytes < ih.len) {
1143 spin_unlock(&fiq->lock);
1144 return -EINVAL;
1145 }
1146
1147 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1148 head = fuse_dequeue_forget(fiq, max_forgets, &count);
1149 spin_unlock(&fiq->lock);
1150
1151 arg.count = count;
1152 ih.len += count * sizeof(struct fuse_forget_one);
1153 err = fuse_copy_one(cs, &ih, sizeof(ih));
1154 if (!err)
1155 err = fuse_copy_one(cs, &arg, sizeof(arg));
1156
1157 while (head) {
1158 struct fuse_forget_link *forget = head;
1159
1160 if (!err) {
1161 err = fuse_copy_one(cs, &forget->forget_one,
1162 sizeof(forget->forget_one));
1163 }
1164 head = forget->next;
1165 kfree(forget);
1166 }
1167
1168 fuse_copy_finish(cs);
1169
1170 if (err)
1171 return err;
1172
1173 return ih.len;
1174 }
1175
1176 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1177 struct fuse_copy_state *cs,
1178 size_t nbytes)
1179 __releases(fiq->lock)
1180 {
1181 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1182 return fuse_read_single_forget(fiq, cs, nbytes);
1183 else
1184 return fuse_read_batch_forget(fiq, cs, nbytes);
1185 }
1186
1187 /*
1188 * Read a single request into the userspace filesystem's buffer. This
1189 * function waits until a request is available, then removes it from
1190 * the pending list and copies request data to userspace buffer. If
1191 * no reply is needed (FORGET) or request has been aborted or there
1192 * was an error during the copying then it's finished by calling
1193 * fuse_request_end(). Otherwise add it to the processing list, and set
1194 * the 'sent' flag.
1195 */
1196 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1197 struct fuse_copy_state *cs, size_t nbytes)
1198 {
1199 ssize_t err;
1200 struct fuse_conn *fc = fud->fc;
1201 struct fuse_iqueue *fiq = &fc->iq;
1202 struct fuse_pqueue *fpq = &fud->pq;
1203 struct fuse_req *req;
1204 struct fuse_args *args;
1205 unsigned reqsize;
1206 unsigned int hash;
1207
1208 /*
1209 * Require sane minimum read buffer - that has capacity for fixed part
1210 * of any request header + negotiated max_write room for data.
1211 *
1212 * Historically libfuse reserves 4K for fixed header room, but e.g.
1213 * GlusterFS reserves only 80 bytes
1214 *
1215 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1216 *
1217 * which is the absolute minimum any sane filesystem should be using
1218 * for header room.
1219 */
1220 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1221 sizeof(struct fuse_in_header) +
1222 sizeof(struct fuse_write_in) +
1223 fc->max_write))
1224 return -EINVAL;
1225
1226 restart:
1227 for (;;) {
1228 spin_lock(&fiq->lock);
1229 if (!fiq->connected || request_pending(fiq))
1230 break;
1231 spin_unlock(&fiq->lock);
1232
1233 if (file->f_flags & O_NONBLOCK)
1234 return -EAGAIN;
1235 err = wait_event_interruptible_exclusive(fiq->waitq,
1236 !fiq->connected || request_pending(fiq));
1237 if (err)
1238 return err;
1239 }
1240
1241 if (!fiq->connected) {
1242 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1243 goto err_unlock;
1244 }
1245
1246 if (!list_empty(&fiq->interrupts)) {
1247 req = list_entry(fiq->interrupts.next, struct fuse_req,
1248 intr_entry);
1249 return fuse_read_interrupt(fiq, cs, nbytes, req);
1250 }
1251
1252 if (forget_pending(fiq)) {
1253 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1254 return fuse_read_forget(fc, fiq, cs, nbytes);
1255
1256 if (fiq->forget_batch <= -8)
1257 fiq->forget_batch = 16;
1258 }
1259
1260 req = list_entry(fiq->pending.next, struct fuse_req, list);
1261 clear_bit(FR_PENDING, &req->flags);
1262 list_del_init(&req->list);
1263 spin_unlock(&fiq->lock);
1264
1265 args = req->args;
1266 reqsize = req->in.h.len;
1267
1268 /* If request is too large, reply with an error and restart the read */
1269 if (nbytes < reqsize) {
1270 req->out.h.error = -EIO;
1271 /* SETXATTR is special, since it may contain too large data */
1272 if (args->opcode == FUSE_SETXATTR)
1273 req->out.h.error = -E2BIG;
1274 fuse_request_end(req);
1275 goto restart;
1276 }
1277 spin_lock(&fpq->lock);
1278 list_add(&req->list, &fpq->io);
1279 spin_unlock(&fpq->lock);
1280 cs->req = req;
1281 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1282 if (!err)
1283 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1284 (struct fuse_arg *) args->in_args, 0);
1285 fuse_copy_finish(cs);
1286 spin_lock(&fpq->lock);
1287 clear_bit(FR_LOCKED, &req->flags);
1288 if (!fpq->connected) {
1289 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1290 goto out_end;
1291 }
1292 if (err) {
1293 req->out.h.error = -EIO;
1294 goto out_end;
1295 }
1296 if (!test_bit(FR_ISREPLY, &req->flags)) {
1297 err = reqsize;
1298 goto out_end;
1299 }
1300 hash = fuse_req_hash(req->in.h.unique);
1301 list_move_tail(&req->list, &fpq->processing[hash]);
1302 __fuse_get_request(req);
1303 set_bit(FR_SENT, &req->flags);
1304 spin_unlock(&fpq->lock);
1305 /* matches barrier in request_wait_answer() */
1306 smp_mb__after_atomic();
1307 if (test_bit(FR_INTERRUPTED, &req->flags))
1308 queue_interrupt(req);
1309 fuse_put_request(req);
1310
1311 return reqsize;
1312
1313 out_end:
1314 if (!test_bit(FR_PRIVATE, &req->flags))
1315 list_del_init(&req->list);
1316 spin_unlock(&fpq->lock);
1317 fuse_request_end(req);
1318 return err;
1319
1320 err_unlock:
1321 spin_unlock(&fiq->lock);
1322 return err;
1323 }
1324
1325 static int fuse_dev_open(struct inode *inode, struct file *file)
1326 {
1327 /*
1328 * The fuse device's file's private_data is used to hold
1329 * the fuse_conn(ection) when it is mounted, and is used to
1330 * keep track of whether the file has been mounted already.
1331 */
1332 file->private_data = NULL;
1333 return 0;
1334 }
1335
1336 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1337 {
1338 struct fuse_copy_state cs;
1339 struct file *file = iocb->ki_filp;
1340 struct fuse_dev *fud = fuse_get_dev(file);
1341
1342 if (!fud)
1343 return -EPERM;
1344
1345 if (!iter_is_iovec(to))
1346 return -EINVAL;
1347
1348 fuse_copy_init(&cs, 1, to);
1349
1350 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1351 }
1352
1353 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1354 struct pipe_inode_info *pipe,
1355 size_t len, unsigned int flags)
1356 {
1357 int total, ret;
1358 int page_nr = 0;
1359 struct pipe_buffer *bufs;
1360 struct fuse_copy_state cs;
1361 struct fuse_dev *fud = fuse_get_dev(in);
1362
1363 if (!fud)
1364 return -EPERM;
1365
1366 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1367 GFP_KERNEL);
1368 if (!bufs)
1369 return -ENOMEM;
1370
1371 fuse_copy_init(&cs, 1, NULL);
1372 cs.pipebufs = bufs;
1373 cs.pipe = pipe;
1374 ret = fuse_dev_do_read(fud, in, &cs, len);
1375 if (ret < 0)
1376 goto out;
1377
1378 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1379 ret = -EIO;
1380 goto out;
1381 }
1382
1383 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1384 /*
1385 * Need to be careful about this. Having buf->ops in module
1386 * code can Oops if the buffer persists after module unload.
1387 */
1388 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1389 bufs[page_nr].flags = 0;
1390 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1391 if (unlikely(ret < 0))
1392 break;
1393 }
1394 if (total)
1395 ret = total;
1396 out:
1397 for (; page_nr < cs.nr_segs; page_nr++)
1398 put_page(bufs[page_nr].page);
1399
1400 kvfree(bufs);
1401 return ret;
1402 }
1403
1404 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1405 struct fuse_copy_state *cs)
1406 {
1407 struct fuse_notify_poll_wakeup_out outarg;
1408 int err = -EINVAL;
1409
1410 if (size != sizeof(outarg))
1411 goto err;
1412
1413 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1414 if (err)
1415 goto err;
1416
1417 fuse_copy_finish(cs);
1418 return fuse_notify_poll_wakeup(fc, &outarg);
1419
1420 err:
1421 fuse_copy_finish(cs);
1422 return err;
1423 }
1424
1425 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1426 struct fuse_copy_state *cs)
1427 {
1428 struct fuse_notify_inval_inode_out outarg;
1429 int err = -EINVAL;
1430
1431 if (size != sizeof(outarg))
1432 goto err;
1433
1434 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1435 if (err)
1436 goto err;
1437 fuse_copy_finish(cs);
1438
1439 down_read(&fc->killsb);
1440 err = fuse_reverse_inval_inode(fc, outarg.ino,
1441 outarg.off, outarg.len);
1442 up_read(&fc->killsb);
1443 return err;
1444
1445 err:
1446 fuse_copy_finish(cs);
1447 return err;
1448 }
1449
1450 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1451 struct fuse_copy_state *cs)
1452 {
1453 struct fuse_notify_inval_entry_out outarg;
1454 int err = -ENOMEM;
1455 char *buf;
1456 struct qstr name;
1457
1458 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1459 if (!buf)
1460 goto err;
1461
1462 err = -EINVAL;
1463 if (size < sizeof(outarg))
1464 goto err;
1465
1466 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1467 if (err)
1468 goto err;
1469
1470 err = -ENAMETOOLONG;
1471 if (outarg.namelen > FUSE_NAME_MAX)
1472 goto err;
1473
1474 err = -EINVAL;
1475 if (size != sizeof(outarg) + outarg.namelen + 1)
1476 goto err;
1477
1478 name.name = buf;
1479 name.len = outarg.namelen;
1480 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1481 if (err)
1482 goto err;
1483 fuse_copy_finish(cs);
1484 buf[outarg.namelen] = 0;
1485
1486 down_read(&fc->killsb);
1487 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name);
1488 up_read(&fc->killsb);
1489 kfree(buf);
1490 return err;
1491
1492 err:
1493 kfree(buf);
1494 fuse_copy_finish(cs);
1495 return err;
1496 }
1497
1498 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1499 struct fuse_copy_state *cs)
1500 {
1501 struct fuse_notify_delete_out outarg;
1502 int err = -ENOMEM;
1503 char *buf;
1504 struct qstr name;
1505
1506 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1507 if (!buf)
1508 goto err;
1509
1510 err = -EINVAL;
1511 if (size < sizeof(outarg))
1512 goto err;
1513
1514 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1515 if (err)
1516 goto err;
1517
1518 err = -ENAMETOOLONG;
1519 if (outarg.namelen > FUSE_NAME_MAX)
1520 goto err;
1521
1522 err = -EINVAL;
1523 if (size != sizeof(outarg) + outarg.namelen + 1)
1524 goto err;
1525
1526 name.name = buf;
1527 name.len = outarg.namelen;
1528 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1529 if (err)
1530 goto err;
1531 fuse_copy_finish(cs);
1532 buf[outarg.namelen] = 0;
1533
1534 down_read(&fc->killsb);
1535 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name);
1536 up_read(&fc->killsb);
1537 kfree(buf);
1538 return err;
1539
1540 err:
1541 kfree(buf);
1542 fuse_copy_finish(cs);
1543 return err;
1544 }
1545
1546 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1547 struct fuse_copy_state *cs)
1548 {
1549 struct fuse_notify_store_out outarg;
1550 struct inode *inode;
1551 struct address_space *mapping;
1552 u64 nodeid;
1553 int err;
1554 pgoff_t index;
1555 unsigned int offset;
1556 unsigned int num;
1557 loff_t file_size;
1558 loff_t end;
1559
1560 err = -EINVAL;
1561 if (size < sizeof(outarg))
1562 goto out_finish;
1563
1564 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1565 if (err)
1566 goto out_finish;
1567
1568 err = -EINVAL;
1569 if (size - sizeof(outarg) != outarg.size)
1570 goto out_finish;
1571
1572 nodeid = outarg.nodeid;
1573
1574 down_read(&fc->killsb);
1575
1576 err = -ENOENT;
1577 inode = fuse_ilookup(fc, nodeid, NULL);
1578 if (!inode)
1579 goto out_up_killsb;
1580
1581 mapping = inode->i_mapping;
1582 index = outarg.offset >> PAGE_SHIFT;
1583 offset = outarg.offset & ~PAGE_MASK;
1584 file_size = i_size_read(inode);
1585 end = outarg.offset + outarg.size;
1586 if (end > file_size) {
1587 file_size = end;
1588 fuse_write_update_size(inode, file_size);
1589 }
1590
1591 num = outarg.size;
1592 while (num) {
1593 struct page *page;
1594 unsigned int this_num;
1595
1596 err = -ENOMEM;
1597 page = find_or_create_page(mapping, index,
1598 mapping_gfp_mask(mapping));
1599 if (!page)
1600 goto out_iput;
1601
1602 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1603 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1604 if (!err && offset == 0 &&
1605 (this_num == PAGE_SIZE || file_size == end))
1606 SetPageUptodate(page);
1607 unlock_page(page);
1608 put_page(page);
1609
1610 if (err)
1611 goto out_iput;
1612
1613 num -= this_num;
1614 offset = 0;
1615 index++;
1616 }
1617
1618 err = 0;
1619
1620 out_iput:
1621 iput(inode);
1622 out_up_killsb:
1623 up_read(&fc->killsb);
1624 out_finish:
1625 fuse_copy_finish(cs);
1626 return err;
1627 }
1628
1629 struct fuse_retrieve_args {
1630 struct fuse_args_pages ap;
1631 struct fuse_notify_retrieve_in inarg;
1632 };
1633
1634 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1635 int error)
1636 {
1637 struct fuse_retrieve_args *ra =
1638 container_of(args, typeof(*ra), ap.args);
1639
1640 release_pages(ra->ap.pages, ra->ap.num_pages);
1641 kfree(ra);
1642 }
1643
1644 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1645 struct fuse_notify_retrieve_out *outarg)
1646 {
1647 int err;
1648 struct address_space *mapping = inode->i_mapping;
1649 pgoff_t index;
1650 loff_t file_size;
1651 unsigned int num;
1652 unsigned int offset;
1653 size_t total_len = 0;
1654 unsigned int num_pages;
1655 struct fuse_conn *fc = fm->fc;
1656 struct fuse_retrieve_args *ra;
1657 size_t args_size = sizeof(*ra);
1658 struct fuse_args_pages *ap;
1659 struct fuse_args *args;
1660
1661 offset = outarg->offset & ~PAGE_MASK;
1662 file_size = i_size_read(inode);
1663
1664 num = min(outarg->size, fc->max_write);
1665 if (outarg->offset > file_size)
1666 num = 0;
1667 else if (outarg->offset + num > file_size)
1668 num = file_size - outarg->offset;
1669
1670 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1671 num_pages = min(num_pages, fc->max_pages);
1672
1673 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1674
1675 ra = kzalloc(args_size, GFP_KERNEL);
1676 if (!ra)
1677 return -ENOMEM;
1678
1679 ap = &ra->ap;
1680 ap->pages = (void *) (ra + 1);
1681 ap->descs = (void *) (ap->pages + num_pages);
1682
1683 args = &ap->args;
1684 args->nodeid = outarg->nodeid;
1685 args->opcode = FUSE_NOTIFY_REPLY;
1686 args->in_numargs = 2;
1687 args->in_pages = true;
1688 args->end = fuse_retrieve_end;
1689
1690 index = outarg->offset >> PAGE_SHIFT;
1691
1692 while (num && ap->num_pages < num_pages) {
1693 struct page *page;
1694 unsigned int this_num;
1695
1696 page = find_get_page(mapping, index);
1697 if (!page)
1698 break;
1699
1700 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1701 ap->pages[ap->num_pages] = page;
1702 ap->descs[ap->num_pages].offset = offset;
1703 ap->descs[ap->num_pages].length = this_num;
1704 ap->num_pages++;
1705
1706 offset = 0;
1707 num -= this_num;
1708 total_len += this_num;
1709 index++;
1710 }
1711 ra->inarg.offset = outarg->offset;
1712 ra->inarg.size = total_len;
1713 args->in_args[0].size = sizeof(ra->inarg);
1714 args->in_args[0].value = &ra->inarg;
1715 args->in_args[1].size = total_len;
1716
1717 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1718 if (err)
1719 fuse_retrieve_end(fm, args, err);
1720
1721 return err;
1722 }
1723
1724 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1725 struct fuse_copy_state *cs)
1726 {
1727 struct fuse_notify_retrieve_out outarg;
1728 struct fuse_mount *fm;
1729 struct inode *inode;
1730 u64 nodeid;
1731 int err;
1732
1733 err = -EINVAL;
1734 if (size != sizeof(outarg))
1735 goto copy_finish;
1736
1737 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1738 if (err)
1739 goto copy_finish;
1740
1741 fuse_copy_finish(cs);
1742
1743 down_read(&fc->killsb);
1744 err = -ENOENT;
1745 nodeid = outarg.nodeid;
1746
1747 inode = fuse_ilookup(fc, nodeid, &fm);
1748 if (inode) {
1749 err = fuse_retrieve(fm, inode, &outarg);
1750 iput(inode);
1751 }
1752 up_read(&fc->killsb);
1753
1754 return err;
1755
1756 copy_finish:
1757 fuse_copy_finish(cs);
1758 return err;
1759 }
1760
1761 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1762 unsigned int size, struct fuse_copy_state *cs)
1763 {
1764 /* Don't try to move pages (yet) */
1765 cs->move_pages = 0;
1766
1767 switch (code) {
1768 case FUSE_NOTIFY_POLL:
1769 return fuse_notify_poll(fc, size, cs);
1770
1771 case FUSE_NOTIFY_INVAL_INODE:
1772 return fuse_notify_inval_inode(fc, size, cs);
1773
1774 case FUSE_NOTIFY_INVAL_ENTRY:
1775 return fuse_notify_inval_entry(fc, size, cs);
1776
1777 case FUSE_NOTIFY_STORE:
1778 return fuse_notify_store(fc, size, cs);
1779
1780 case FUSE_NOTIFY_RETRIEVE:
1781 return fuse_notify_retrieve(fc, size, cs);
1782
1783 case FUSE_NOTIFY_DELETE:
1784 return fuse_notify_delete(fc, size, cs);
1785
1786 default:
1787 fuse_copy_finish(cs);
1788 return -EINVAL;
1789 }
1790 }
1791
1792 /* Look up request on processing list by unique ID */
1793 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1794 {
1795 unsigned int hash = fuse_req_hash(unique);
1796 struct fuse_req *req;
1797
1798 list_for_each_entry(req, &fpq->processing[hash], list) {
1799 if (req->in.h.unique == unique)
1800 return req;
1801 }
1802 return NULL;
1803 }
1804
1805 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1806 unsigned nbytes)
1807 {
1808 unsigned reqsize = sizeof(struct fuse_out_header);
1809
1810 reqsize += fuse_len_args(args->out_numargs, args->out_args);
1811
1812 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1813 return -EINVAL;
1814 else if (reqsize > nbytes) {
1815 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1816 unsigned diffsize = reqsize - nbytes;
1817
1818 if (diffsize > lastarg->size)
1819 return -EINVAL;
1820 lastarg->size -= diffsize;
1821 }
1822 return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1823 args->out_args, args->page_zeroing);
1824 }
1825
1826 /*
1827 * Write a single reply to a request. First the header is copied from
1828 * the write buffer. The request is then searched on the processing
1829 * list by the unique ID found in the header. If found, then remove
1830 * it from the list and copy the rest of the buffer to the request.
1831 * The request is finished by calling fuse_request_end().
1832 */
1833 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1834 struct fuse_copy_state *cs, size_t nbytes)
1835 {
1836 int err;
1837 struct fuse_conn *fc = fud->fc;
1838 struct fuse_pqueue *fpq = &fud->pq;
1839 struct fuse_req *req;
1840 struct fuse_out_header oh;
1841
1842 err = -EINVAL;
1843 if (nbytes < sizeof(struct fuse_out_header))
1844 goto out;
1845
1846 err = fuse_copy_one(cs, &oh, sizeof(oh));
1847 if (err)
1848 goto copy_finish;
1849
1850 err = -EINVAL;
1851 if (oh.len != nbytes)
1852 goto copy_finish;
1853
1854 /*
1855 * Zero oh.unique indicates unsolicited notification message
1856 * and error contains notification code.
1857 */
1858 if (!oh.unique) {
1859 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1860 goto out;
1861 }
1862
1863 err = -EINVAL;
1864 if (oh.error <= -1000 || oh.error > 0)
1865 goto copy_finish;
1866
1867 spin_lock(&fpq->lock);
1868 req = NULL;
1869 if (fpq->connected)
1870 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1871
1872 err = -ENOENT;
1873 if (!req) {
1874 spin_unlock(&fpq->lock);
1875 goto copy_finish;
1876 }
1877
1878 /* Is it an interrupt reply ID? */
1879 if (oh.unique & FUSE_INT_REQ_BIT) {
1880 __fuse_get_request(req);
1881 spin_unlock(&fpq->lock);
1882
1883 err = 0;
1884 if (nbytes != sizeof(struct fuse_out_header))
1885 err = -EINVAL;
1886 else if (oh.error == -ENOSYS)
1887 fc->no_interrupt = 1;
1888 else if (oh.error == -EAGAIN)
1889 err = queue_interrupt(req);
1890
1891 fuse_put_request(req);
1892
1893 goto copy_finish;
1894 }
1895
1896 clear_bit(FR_SENT, &req->flags);
1897 list_move(&req->list, &fpq->io);
1898 req->out.h = oh;
1899 set_bit(FR_LOCKED, &req->flags);
1900 spin_unlock(&fpq->lock);
1901 cs->req = req;
1902 if (!req->args->page_replace)
1903 cs->move_pages = 0;
1904
1905 if (oh.error)
1906 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1907 else
1908 err = copy_out_args(cs, req->args, nbytes);
1909 fuse_copy_finish(cs);
1910
1911 spin_lock(&fpq->lock);
1912 clear_bit(FR_LOCKED, &req->flags);
1913 if (!fpq->connected)
1914 err = -ENOENT;
1915 else if (err)
1916 req->out.h.error = -EIO;
1917 if (!test_bit(FR_PRIVATE, &req->flags))
1918 list_del_init(&req->list);
1919 spin_unlock(&fpq->lock);
1920
1921 fuse_request_end(req);
1922 out:
1923 return err ? err : nbytes;
1924
1925 copy_finish:
1926 fuse_copy_finish(cs);
1927 goto out;
1928 }
1929
1930 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1931 {
1932 struct fuse_copy_state cs;
1933 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1934
1935 if (!fud)
1936 return -EPERM;
1937
1938 if (!iter_is_iovec(from))
1939 return -EINVAL;
1940
1941 fuse_copy_init(&cs, 0, from);
1942
1943 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1944 }
1945
1946 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1947 struct file *out, loff_t *ppos,
1948 size_t len, unsigned int flags)
1949 {
1950 unsigned int head, tail, mask, count;
1951 unsigned nbuf;
1952 unsigned idx;
1953 struct pipe_buffer *bufs;
1954 struct fuse_copy_state cs;
1955 struct fuse_dev *fud;
1956 size_t rem;
1957 ssize_t ret;
1958
1959 fud = fuse_get_dev(out);
1960 if (!fud)
1961 return -EPERM;
1962
1963 pipe_lock(pipe);
1964
1965 head = pipe->head;
1966 tail = pipe->tail;
1967 mask = pipe->ring_size - 1;
1968 count = head - tail;
1969
1970 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1971 if (!bufs) {
1972 pipe_unlock(pipe);
1973 return -ENOMEM;
1974 }
1975
1976 nbuf = 0;
1977 rem = 0;
1978 for (idx = tail; idx != head && rem < len; idx++)
1979 rem += pipe->bufs[idx & mask].len;
1980
1981 ret = -EINVAL;
1982 if (rem < len)
1983 goto out_free;
1984
1985 rem = len;
1986 while (rem) {
1987 struct pipe_buffer *ibuf;
1988 struct pipe_buffer *obuf;
1989
1990 if (WARN_ON(nbuf >= count || tail == head))
1991 goto out_free;
1992
1993 ibuf = &pipe->bufs[tail & mask];
1994 obuf = &bufs[nbuf];
1995
1996 if (rem >= ibuf->len) {
1997 *obuf = *ibuf;
1998 ibuf->ops = NULL;
1999 tail++;
2000 pipe->tail = tail;
2001 } else {
2002 if (!pipe_buf_get(pipe, ibuf))
2003 goto out_free;
2004
2005 *obuf = *ibuf;
2006 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2007 obuf->len = rem;
2008 ibuf->offset += obuf->len;
2009 ibuf->len -= obuf->len;
2010 }
2011 nbuf++;
2012 rem -= obuf->len;
2013 }
2014 pipe_unlock(pipe);
2015
2016 fuse_copy_init(&cs, 0, NULL);
2017 cs.pipebufs = bufs;
2018 cs.nr_segs = nbuf;
2019 cs.pipe = pipe;
2020
2021 if (flags & SPLICE_F_MOVE)
2022 cs.move_pages = 1;
2023
2024 ret = fuse_dev_do_write(fud, &cs, len);
2025
2026 pipe_lock(pipe);
2027 out_free:
2028 for (idx = 0; idx < nbuf; idx++)
2029 pipe_buf_release(pipe, &bufs[idx]);
2030 pipe_unlock(pipe);
2031
2032 kvfree(bufs);
2033 return ret;
2034 }
2035
2036 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2037 {
2038 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2039 struct fuse_iqueue *fiq;
2040 struct fuse_dev *fud = fuse_get_dev(file);
2041
2042 if (!fud)
2043 return EPOLLERR;
2044
2045 fiq = &fud->fc->iq;
2046 poll_wait(file, &fiq->waitq, wait);
2047
2048 spin_lock(&fiq->lock);
2049 if (!fiq->connected)
2050 mask = EPOLLERR;
2051 else if (request_pending(fiq))
2052 mask |= EPOLLIN | EPOLLRDNORM;
2053 spin_unlock(&fiq->lock);
2054
2055 return mask;
2056 }
2057
2058 /* Abort all requests on the given list (pending or processing) */
2059 static void end_requests(struct list_head *head)
2060 {
2061 while (!list_empty(head)) {
2062 struct fuse_req *req;
2063 req = list_entry(head->next, struct fuse_req, list);
2064 req->out.h.error = -ECONNABORTED;
2065 clear_bit(FR_SENT, &req->flags);
2066 list_del_init(&req->list);
2067 fuse_request_end(req);
2068 }
2069 }
2070
2071 static void end_polls(struct fuse_conn *fc)
2072 {
2073 struct rb_node *p;
2074
2075 p = rb_first(&fc->polled_files);
2076
2077 while (p) {
2078 struct fuse_file *ff;
2079 ff = rb_entry(p, struct fuse_file, polled_node);
2080 wake_up_interruptible_all(&ff->poll_wait);
2081
2082 p = rb_next(p);
2083 }
2084 }
2085
2086 /*
2087 * Abort all requests.
2088 *
2089 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2090 * filesystem.
2091 *
2092 * The same effect is usually achievable through killing the filesystem daemon
2093 * and all users of the filesystem. The exception is the combination of an
2094 * asynchronous request and the tricky deadlock (see
2095 * Documentation/filesystems/fuse.rst).
2096 *
2097 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2098 * requests, they should be finished off immediately. Locked requests will be
2099 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2100 * requests. It is possible that some request will finish before we can. This
2101 * is OK, the request will in that case be removed from the list before we touch
2102 * it.
2103 */
2104 void fuse_abort_conn(struct fuse_conn *fc)
2105 {
2106 struct fuse_iqueue *fiq = &fc->iq;
2107
2108 spin_lock(&fc->lock);
2109 if (fc->connected) {
2110 struct fuse_dev *fud;
2111 struct fuse_req *req, *next;
2112 LIST_HEAD(to_end);
2113 unsigned int i;
2114
2115 /* Background queuing checks fc->connected under bg_lock */
2116 spin_lock(&fc->bg_lock);
2117 fc->connected = 0;
2118 spin_unlock(&fc->bg_lock);
2119
2120 fuse_set_initialized(fc);
2121 list_for_each_entry(fud, &fc->devices, entry) {
2122 struct fuse_pqueue *fpq = &fud->pq;
2123
2124 spin_lock(&fpq->lock);
2125 fpq->connected = 0;
2126 list_for_each_entry_safe(req, next, &fpq->io, list) {
2127 req->out.h.error = -ECONNABORTED;
2128 spin_lock(&req->waitq.lock);
2129 set_bit(FR_ABORTED, &req->flags);
2130 if (!test_bit(FR_LOCKED, &req->flags)) {
2131 set_bit(FR_PRIVATE, &req->flags);
2132 __fuse_get_request(req);
2133 list_move(&req->list, &to_end);
2134 }
2135 spin_unlock(&req->waitq.lock);
2136 }
2137 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2138 list_splice_tail_init(&fpq->processing[i],
2139 &to_end);
2140 spin_unlock(&fpq->lock);
2141 }
2142 spin_lock(&fc->bg_lock);
2143 fc->blocked = 0;
2144 fc->max_background = UINT_MAX;
2145 flush_bg_queue(fc);
2146 spin_unlock(&fc->bg_lock);
2147
2148 spin_lock(&fiq->lock);
2149 fiq->connected = 0;
2150 list_for_each_entry(req, &fiq->pending, list)
2151 clear_bit(FR_PENDING, &req->flags);
2152 list_splice_tail_init(&fiq->pending, &to_end);
2153 while (forget_pending(fiq))
2154 kfree(fuse_dequeue_forget(fiq, 1, NULL));
2155 wake_up_all(&fiq->waitq);
2156 spin_unlock(&fiq->lock);
2157 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2158 end_polls(fc);
2159 wake_up_all(&fc->blocked_waitq);
2160 spin_unlock(&fc->lock);
2161
2162 end_requests(&to_end);
2163 } else {
2164 spin_unlock(&fc->lock);
2165 }
2166 }
2167 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2168
2169 void fuse_wait_aborted(struct fuse_conn *fc)
2170 {
2171 /* matches implicit memory barrier in fuse_drop_waiting() */
2172 smp_mb();
2173 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2174 }
2175
2176 int fuse_dev_release(struct inode *inode, struct file *file)
2177 {
2178 struct fuse_dev *fud = fuse_get_dev(file);
2179
2180 if (fud) {
2181 struct fuse_conn *fc = fud->fc;
2182 struct fuse_pqueue *fpq = &fud->pq;
2183 LIST_HEAD(to_end);
2184 unsigned int i;
2185
2186 spin_lock(&fpq->lock);
2187 WARN_ON(!list_empty(&fpq->io));
2188 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2189 list_splice_init(&fpq->processing[i], &to_end);
2190 spin_unlock(&fpq->lock);
2191
2192 end_requests(&to_end);
2193
2194 /* Are we the last open device? */
2195 if (atomic_dec_and_test(&fc->dev_count)) {
2196 WARN_ON(fc->iq.fasync != NULL);
2197 fuse_abort_conn(fc);
2198 }
2199 fuse_dev_free(fud);
2200 }
2201 return 0;
2202 }
2203 EXPORT_SYMBOL_GPL(fuse_dev_release);
2204
2205 static int fuse_dev_fasync(int fd, struct file *file, int on)
2206 {
2207 struct fuse_dev *fud = fuse_get_dev(file);
2208
2209 if (!fud)
2210 return -EPERM;
2211
2212 /* No locking - fasync_helper does its own locking */
2213 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2214 }
2215
2216 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2217 {
2218 struct fuse_dev *fud;
2219
2220 if (new->private_data)
2221 return -EINVAL;
2222
2223 fud = fuse_dev_alloc_install(fc);
2224 if (!fud)
2225 return -ENOMEM;
2226
2227 new->private_data = fud;
2228 atomic_inc(&fc->dev_count);
2229
2230 return 0;
2231 }
2232
2233 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2234 unsigned long arg)
2235 {
2236 int err = -ENOTTY;
2237
2238 if (cmd == FUSE_DEV_IOC_CLONE) {
2239 int oldfd;
2240
2241 err = -EFAULT;
2242 if (!get_user(oldfd, (__u32 __user *) arg)) {
2243 struct file *old = fget(oldfd);
2244
2245 err = -EINVAL;
2246 if (old) {
2247 struct fuse_dev *fud = NULL;
2248
2249 /*
2250 * Check against file->f_op because CUSE
2251 * uses the same ioctl handler.
2252 */
2253 if (old->f_op == file->f_op &&
2254 old->f_cred->user_ns == file->f_cred->user_ns)
2255 fud = fuse_get_dev(old);
2256
2257 if (fud) {
2258 mutex_lock(&fuse_mutex);
2259 err = fuse_device_clone(fud->fc, file);
2260 mutex_unlock(&fuse_mutex);
2261 }
2262 fput(old);
2263 }
2264 }
2265 }
2266 return err;
2267 }
2268
2269 const struct file_operations fuse_dev_operations = {
2270 .owner = THIS_MODULE,
2271 .open = fuse_dev_open,
2272 .llseek = no_llseek,
2273 .read_iter = fuse_dev_read,
2274 .splice_read = fuse_dev_splice_read,
2275 .write_iter = fuse_dev_write,
2276 .splice_write = fuse_dev_splice_write,
2277 .poll = fuse_dev_poll,
2278 .release = fuse_dev_release,
2279 .fasync = fuse_dev_fasync,
2280 .unlocked_ioctl = fuse_dev_ioctl,
2281 .compat_ioctl = compat_ptr_ioctl,
2282 };
2283 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2284
2285 static struct miscdevice fuse_miscdevice = {
2286 .minor = FUSE_MINOR,
2287 .name = "fuse",
2288 .fops = &fuse_dev_operations,
2289 };
2290
2291 int __init fuse_dev_init(void)
2292 {
2293 int err = -ENOMEM;
2294 fuse_req_cachep = kmem_cache_create("fuse_request",
2295 sizeof(struct fuse_req),
2296 0, 0, NULL);
2297 if (!fuse_req_cachep)
2298 goto out;
2299
2300 err = misc_register(&fuse_miscdevice);
2301 if (err)
2302 goto out_cache_clean;
2303
2304 return 0;
2305
2306 out_cache_clean:
2307 kmem_cache_destroy(fuse_req_cachep);
2308 out:
2309 return err;
2310 }
2311
2312 void fuse_dev_cleanup(void)
2313 {
2314 misc_deregister(&fuse_miscdevice);
2315 kmem_cache_destroy(fuse_req_cachep);
2316 }
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