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Merge tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
[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_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 }
51
52 static struct fuse_req *fuse_request_alloc(gfp_t flags)
53 {
54 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
55 if (req)
56 fuse_request_init(req);
57
58 return req;
59 }
60
61 static void fuse_request_free(struct fuse_req *req)
62 {
63 kmem_cache_free(fuse_req_cachep, req);
64 }
65
66 static void __fuse_get_request(struct fuse_req *req)
67 {
68 refcount_inc(&req->count);
69 }
70
71 /* Must be called with > 1 refcount */
72 static void __fuse_put_request(struct fuse_req *req)
73 {
74 refcount_dec(&req->count);
75 }
76
77 void fuse_set_initialized(struct fuse_conn *fc)
78 {
79 /* Make sure stores before this are seen on another CPU */
80 smp_wmb();
81 fc->initialized = 1;
82 }
83
84 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
85 {
86 return !fc->initialized || (for_background && fc->blocked);
87 }
88
89 static void fuse_drop_waiting(struct fuse_conn *fc)
90 {
91 /*
92 * lockess check of fc->connected is okay, because atomic_dec_and_test()
93 * provides a memory barrier mached with the one in fuse_wait_aborted()
94 * to ensure no wake-up is missed.
95 */
96 if (atomic_dec_and_test(&fc->num_waiting) &&
97 !READ_ONCE(fc->connected)) {
98 /* wake up aborters */
99 wake_up_all(&fc->blocked_waitq);
100 }
101 }
102
103 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
104
105 static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background)
106 {
107 struct fuse_req *req;
108 int err;
109 atomic_inc(&fc->num_waiting);
110
111 if (fuse_block_alloc(fc, for_background)) {
112 err = -EINTR;
113 if (wait_event_killable_exclusive(fc->blocked_waitq,
114 !fuse_block_alloc(fc, for_background)))
115 goto out;
116 }
117 /* Matches smp_wmb() in fuse_set_initialized() */
118 smp_rmb();
119
120 err = -ENOTCONN;
121 if (!fc->connected)
122 goto out;
123
124 err = -ECONNREFUSED;
125 if (fc->conn_error)
126 goto out;
127
128 req = fuse_request_alloc(GFP_KERNEL);
129 err = -ENOMEM;
130 if (!req) {
131 if (for_background)
132 wake_up(&fc->blocked_waitq);
133 goto out;
134 }
135
136 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
137 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
138 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
139
140 __set_bit(FR_WAITING, &req->flags);
141 if (for_background)
142 __set_bit(FR_BACKGROUND, &req->flags);
143
144 if (unlikely(req->in.h.uid == ((uid_t)-1) ||
145 req->in.h.gid == ((gid_t)-1))) {
146 fuse_put_request(fc, req);
147 return ERR_PTR(-EOVERFLOW);
148 }
149 return req;
150
151 out:
152 fuse_drop_waiting(fc);
153 return ERR_PTR(err);
154 }
155
156 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
157 {
158 if (refcount_dec_and_test(&req->count)) {
159 if (test_bit(FR_BACKGROUND, &req->flags)) {
160 /*
161 * We get here in the unlikely case that a background
162 * request was allocated but not sent
163 */
164 spin_lock(&fc->bg_lock);
165 if (!fc->blocked)
166 wake_up(&fc->blocked_waitq);
167 spin_unlock(&fc->bg_lock);
168 }
169
170 if (test_bit(FR_WAITING, &req->flags)) {
171 __clear_bit(FR_WAITING, &req->flags);
172 fuse_drop_waiting(fc);
173 }
174
175 fuse_request_free(req);
176 }
177 }
178
179 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
180 {
181 unsigned nbytes = 0;
182 unsigned i;
183
184 for (i = 0; i < numargs; i++)
185 nbytes += args[i].size;
186
187 return nbytes;
188 }
189 EXPORT_SYMBOL_GPL(fuse_len_args);
190
191 u64 fuse_get_unique(struct fuse_iqueue *fiq)
192 {
193 fiq->reqctr += FUSE_REQ_ID_STEP;
194 return fiq->reqctr;
195 }
196 EXPORT_SYMBOL_GPL(fuse_get_unique);
197
198 static unsigned int fuse_req_hash(u64 unique)
199 {
200 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
201 }
202
203 /**
204 * A new request is available, wake fiq->waitq
205 */
206 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
207 __releases(fiq->lock)
208 {
209 wake_up(&fiq->waitq);
210 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
211 spin_unlock(&fiq->lock);
212 }
213
214 const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
215 .wake_forget_and_unlock = fuse_dev_wake_and_unlock,
216 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock,
217 .wake_pending_and_unlock = fuse_dev_wake_and_unlock,
218 };
219 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
220
221 static void queue_request_and_unlock(struct fuse_iqueue *fiq,
222 struct fuse_req *req)
223 __releases(fiq->lock)
224 {
225 req->in.h.len = sizeof(struct fuse_in_header) +
226 fuse_len_args(req->args->in_numargs,
227 (struct fuse_arg *) req->args->in_args);
228 list_add_tail(&req->list, &fiq->pending);
229 fiq->ops->wake_pending_and_unlock(fiq);
230 }
231
232 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
233 u64 nodeid, u64 nlookup)
234 {
235 struct fuse_iqueue *fiq = &fc->iq;
236
237 forget->forget_one.nodeid = nodeid;
238 forget->forget_one.nlookup = nlookup;
239
240 spin_lock(&fiq->lock);
241 if (fiq->connected) {
242 fiq->forget_list_tail->next = forget;
243 fiq->forget_list_tail = forget;
244 fiq->ops->wake_forget_and_unlock(fiq);
245 } else {
246 kfree(forget);
247 spin_unlock(&fiq->lock);
248 }
249 }
250
251 static void flush_bg_queue(struct fuse_conn *fc)
252 {
253 struct fuse_iqueue *fiq = &fc->iq;
254
255 while (fc->active_background < fc->max_background &&
256 !list_empty(&fc->bg_queue)) {
257 struct fuse_req *req;
258
259 req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
260 list_del(&req->list);
261 fc->active_background++;
262 spin_lock(&fiq->lock);
263 req->in.h.unique = fuse_get_unique(fiq);
264 queue_request_and_unlock(fiq, req);
265 }
266 }
267
268 /*
269 * This function is called when a request is finished. Either a reply
270 * has arrived or it was aborted (and not yet sent) or some error
271 * occurred during communication with userspace, or the device file
272 * was closed. The requester thread is woken up (if still waiting),
273 * the 'end' callback is called if given, else the reference to the
274 * request is released
275 */
276 void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req)
277 {
278 struct fuse_iqueue *fiq = &fc->iq;
279
280 if (test_and_set_bit(FR_FINISHED, &req->flags))
281 goto put_request;
282
283 /*
284 * test_and_set_bit() implies smp_mb() between bit
285 * changing and below intr_entry check. Pairs with
286 * smp_mb() from queue_interrupt().
287 */
288 if (!list_empty(&req->intr_entry)) {
289 spin_lock(&fiq->lock);
290 list_del_init(&req->intr_entry);
291 spin_unlock(&fiq->lock);
292 }
293 WARN_ON(test_bit(FR_PENDING, &req->flags));
294 WARN_ON(test_bit(FR_SENT, &req->flags));
295 if (test_bit(FR_BACKGROUND, &req->flags)) {
296 spin_lock(&fc->bg_lock);
297 clear_bit(FR_BACKGROUND, &req->flags);
298 if (fc->num_background == fc->max_background) {
299 fc->blocked = 0;
300 wake_up(&fc->blocked_waitq);
301 } else if (!fc->blocked) {
302 /*
303 * Wake up next waiter, if any. It's okay to use
304 * waitqueue_active(), as we've already synced up
305 * fc->blocked with waiters with the wake_up() call
306 * above.
307 */
308 if (waitqueue_active(&fc->blocked_waitq))
309 wake_up(&fc->blocked_waitq);
310 }
311
312 if (fc->num_background == fc->congestion_threshold && fc->sb) {
313 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
314 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
315 }
316 fc->num_background--;
317 fc->active_background--;
318 flush_bg_queue(fc);
319 spin_unlock(&fc->bg_lock);
320 } else {
321 /* Wake up waiter sleeping in request_wait_answer() */
322 wake_up(&req->waitq);
323 }
324
325 if (test_bit(FR_ASYNC, &req->flags))
326 req->args->end(fc, req->args, req->out.h.error);
327 put_request:
328 fuse_put_request(fc, req);
329 }
330 EXPORT_SYMBOL_GPL(fuse_request_end);
331
332 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
333 {
334 spin_lock(&fiq->lock);
335 /* Check for we've sent request to interrupt this req */
336 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
337 spin_unlock(&fiq->lock);
338 return -EINVAL;
339 }
340
341 if (list_empty(&req->intr_entry)) {
342 list_add_tail(&req->intr_entry, &fiq->interrupts);
343 /*
344 * Pairs with smp_mb() implied by test_and_set_bit()
345 * from request_end().
346 */
347 smp_mb();
348 if (test_bit(FR_FINISHED, &req->flags)) {
349 list_del_init(&req->intr_entry);
350 spin_unlock(&fiq->lock);
351 return 0;
352 }
353 fiq->ops->wake_interrupt_and_unlock(fiq);
354 } else {
355 spin_unlock(&fiq->lock);
356 }
357 return 0;
358 }
359
360 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
361 {
362 struct fuse_iqueue *fiq = &fc->iq;
363 int err;
364
365 if (!fc->no_interrupt) {
366 /* Any signal may interrupt this */
367 err = wait_event_interruptible(req->waitq,
368 test_bit(FR_FINISHED, &req->flags));
369 if (!err)
370 return;
371
372 set_bit(FR_INTERRUPTED, &req->flags);
373 /* matches barrier in fuse_dev_do_read() */
374 smp_mb__after_atomic();
375 if (test_bit(FR_SENT, &req->flags))
376 queue_interrupt(fiq, req);
377 }
378
379 if (!test_bit(FR_FORCE, &req->flags)) {
380 /* Only fatal signals may interrupt this */
381 err = wait_event_killable(req->waitq,
382 test_bit(FR_FINISHED, &req->flags));
383 if (!err)
384 return;
385
386 spin_lock(&fiq->lock);
387 /* Request is not yet in userspace, bail out */
388 if (test_bit(FR_PENDING, &req->flags)) {
389 list_del(&req->list);
390 spin_unlock(&fiq->lock);
391 __fuse_put_request(req);
392 req->out.h.error = -EINTR;
393 return;
394 }
395 spin_unlock(&fiq->lock);
396 }
397
398 /*
399 * Either request is already in userspace, or it was forced.
400 * Wait it out.
401 */
402 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
403 }
404
405 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
406 {
407 struct fuse_iqueue *fiq = &fc->iq;
408
409 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
410 spin_lock(&fiq->lock);
411 if (!fiq->connected) {
412 spin_unlock(&fiq->lock);
413 req->out.h.error = -ENOTCONN;
414 } else {
415 req->in.h.unique = fuse_get_unique(fiq);
416 /* acquire extra reference, since request is still needed
417 after fuse_request_end() */
418 __fuse_get_request(req);
419 queue_request_and_unlock(fiq, req);
420
421 request_wait_answer(fc, req);
422 /* Pairs with smp_wmb() in fuse_request_end() */
423 smp_rmb();
424 }
425 }
426
427 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
428 {
429 if (fc->minor < 4 && args->opcode == FUSE_STATFS)
430 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
431
432 if (fc->minor < 9) {
433 switch (args->opcode) {
434 case FUSE_LOOKUP:
435 case FUSE_CREATE:
436 case FUSE_MKNOD:
437 case FUSE_MKDIR:
438 case FUSE_SYMLINK:
439 case FUSE_LINK:
440 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
441 break;
442 case FUSE_GETATTR:
443 case FUSE_SETATTR:
444 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
445 break;
446 }
447 }
448 if (fc->minor < 12) {
449 switch (args->opcode) {
450 case FUSE_CREATE:
451 args->in_args[0].size = sizeof(struct fuse_open_in);
452 break;
453 case FUSE_MKNOD:
454 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
455 break;
456 }
457 }
458 }
459
460 static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
461 {
462 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
463 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
464 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
465 }
466
467 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
468 {
469 req->in.h.opcode = args->opcode;
470 req->in.h.nodeid = args->nodeid;
471 req->args = args;
472 if (args->end)
473 __set_bit(FR_ASYNC, &req->flags);
474 }
475
476 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
477 {
478 struct fuse_req *req;
479 ssize_t ret;
480
481 if (args->force) {
482 atomic_inc(&fc->num_waiting);
483 req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL);
484
485 if (!args->nocreds)
486 fuse_force_creds(fc, req);
487
488 __set_bit(FR_WAITING, &req->flags);
489 __set_bit(FR_FORCE, &req->flags);
490 } else {
491 WARN_ON(args->nocreds);
492 req = fuse_get_req(fc, false);
493 if (IS_ERR(req))
494 return PTR_ERR(req);
495 }
496
497 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
498 fuse_adjust_compat(fc, args);
499 fuse_args_to_req(req, args);
500
501 if (!args->noreply)
502 __set_bit(FR_ISREPLY, &req->flags);
503 __fuse_request_send(fc, req);
504 ret = req->out.h.error;
505 if (!ret && args->out_argvar) {
506 BUG_ON(args->out_numargs == 0);
507 ret = args->out_args[args->out_numargs - 1].size;
508 }
509 fuse_put_request(fc, req);
510
511 return ret;
512 }
513
514 static bool fuse_request_queue_background(struct fuse_conn *fc,
515 struct fuse_req *req)
516 {
517 bool queued = false;
518
519 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
520 if (!test_bit(FR_WAITING, &req->flags)) {
521 __set_bit(FR_WAITING, &req->flags);
522 atomic_inc(&fc->num_waiting);
523 }
524 __set_bit(FR_ISREPLY, &req->flags);
525 spin_lock(&fc->bg_lock);
526 if (likely(fc->connected)) {
527 fc->num_background++;
528 if (fc->num_background == fc->max_background)
529 fc->blocked = 1;
530 if (fc->num_background == fc->congestion_threshold && fc->sb) {
531 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
532 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
533 }
534 list_add_tail(&req->list, &fc->bg_queue);
535 flush_bg_queue(fc);
536 queued = true;
537 }
538 spin_unlock(&fc->bg_lock);
539
540 return queued;
541 }
542
543 int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
544 gfp_t gfp_flags)
545 {
546 struct fuse_req *req;
547
548 if (args->force) {
549 WARN_ON(!args->nocreds);
550 req = fuse_request_alloc(gfp_flags);
551 if (!req)
552 return -ENOMEM;
553 __set_bit(FR_BACKGROUND, &req->flags);
554 } else {
555 WARN_ON(args->nocreds);
556 req = fuse_get_req(fc, true);
557 if (IS_ERR(req))
558 return PTR_ERR(req);
559 }
560
561 fuse_args_to_req(req, args);
562
563 if (!fuse_request_queue_background(fc, req)) {
564 fuse_put_request(fc, req);
565 return -ENOTCONN;
566 }
567
568 return 0;
569 }
570 EXPORT_SYMBOL_GPL(fuse_simple_background);
571
572 static int fuse_simple_notify_reply(struct fuse_conn *fc,
573 struct fuse_args *args, u64 unique)
574 {
575 struct fuse_req *req;
576 struct fuse_iqueue *fiq = &fc->iq;
577 int err = 0;
578
579 req = fuse_get_req(fc, false);
580 if (IS_ERR(req))
581 return PTR_ERR(req);
582
583 __clear_bit(FR_ISREPLY, &req->flags);
584 req->in.h.unique = unique;
585
586 fuse_args_to_req(req, args);
587
588 spin_lock(&fiq->lock);
589 if (fiq->connected) {
590 queue_request_and_unlock(fiq, req);
591 } else {
592 err = -ENODEV;
593 spin_unlock(&fiq->lock);
594 fuse_put_request(fc, req);
595 }
596
597 return err;
598 }
599
600 /*
601 * Lock the request. Up to the next unlock_request() there mustn't be
602 * anything that could cause a page-fault. If the request was already
603 * aborted bail out.
604 */
605 static int lock_request(struct fuse_req *req)
606 {
607 int err = 0;
608 if (req) {
609 spin_lock(&req->waitq.lock);
610 if (test_bit(FR_ABORTED, &req->flags))
611 err = -ENOENT;
612 else
613 set_bit(FR_LOCKED, &req->flags);
614 spin_unlock(&req->waitq.lock);
615 }
616 return err;
617 }
618
619 /*
620 * Unlock request. If it was aborted while locked, caller is responsible
621 * for unlocking and ending the request.
622 */
623 static int unlock_request(struct fuse_req *req)
624 {
625 int err = 0;
626 if (req) {
627 spin_lock(&req->waitq.lock);
628 if (test_bit(FR_ABORTED, &req->flags))
629 err = -ENOENT;
630 else
631 clear_bit(FR_LOCKED, &req->flags);
632 spin_unlock(&req->waitq.lock);
633 }
634 return err;
635 }
636
637 struct fuse_copy_state {
638 int write;
639 struct fuse_req *req;
640 struct iov_iter *iter;
641 struct pipe_buffer *pipebufs;
642 struct pipe_buffer *currbuf;
643 struct pipe_inode_info *pipe;
644 unsigned long nr_segs;
645 struct page *pg;
646 unsigned len;
647 unsigned offset;
648 unsigned move_pages:1;
649 };
650
651 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
652 struct iov_iter *iter)
653 {
654 memset(cs, 0, sizeof(*cs));
655 cs->write = write;
656 cs->iter = iter;
657 }
658
659 /* Unmap and put previous page of userspace buffer */
660 static void fuse_copy_finish(struct fuse_copy_state *cs)
661 {
662 if (cs->currbuf) {
663 struct pipe_buffer *buf = cs->currbuf;
664
665 if (cs->write)
666 buf->len = PAGE_SIZE - cs->len;
667 cs->currbuf = NULL;
668 } else if (cs->pg) {
669 if (cs->write) {
670 flush_dcache_page(cs->pg);
671 set_page_dirty_lock(cs->pg);
672 }
673 put_page(cs->pg);
674 }
675 cs->pg = NULL;
676 }
677
678 /*
679 * Get another pagefull of userspace buffer, and map it to kernel
680 * address space, and lock request
681 */
682 static int fuse_copy_fill(struct fuse_copy_state *cs)
683 {
684 struct page *page;
685 int err;
686
687 err = unlock_request(cs->req);
688 if (err)
689 return err;
690
691 fuse_copy_finish(cs);
692 if (cs->pipebufs) {
693 struct pipe_buffer *buf = cs->pipebufs;
694
695 if (!cs->write) {
696 err = pipe_buf_confirm(cs->pipe, buf);
697 if (err)
698 return err;
699
700 BUG_ON(!cs->nr_segs);
701 cs->currbuf = buf;
702 cs->pg = buf->page;
703 cs->offset = buf->offset;
704 cs->len = buf->len;
705 cs->pipebufs++;
706 cs->nr_segs--;
707 } else {
708 if (cs->nr_segs >= cs->pipe->max_usage)
709 return -EIO;
710
711 page = alloc_page(GFP_HIGHUSER);
712 if (!page)
713 return -ENOMEM;
714
715 buf->page = page;
716 buf->offset = 0;
717 buf->len = 0;
718
719 cs->currbuf = buf;
720 cs->pg = page;
721 cs->offset = 0;
722 cs->len = PAGE_SIZE;
723 cs->pipebufs++;
724 cs->nr_segs++;
725 }
726 } else {
727 size_t off;
728 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
729 if (err < 0)
730 return err;
731 BUG_ON(!err);
732 cs->len = err;
733 cs->offset = off;
734 cs->pg = page;
735 iov_iter_advance(cs->iter, err);
736 }
737
738 return lock_request(cs->req);
739 }
740
741 /* Do as much copy to/from userspace buffer as we can */
742 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
743 {
744 unsigned ncpy = min(*size, cs->len);
745 if (val) {
746 void *pgaddr = kmap_atomic(cs->pg);
747 void *buf = pgaddr + cs->offset;
748
749 if (cs->write)
750 memcpy(buf, *val, ncpy);
751 else
752 memcpy(*val, buf, ncpy);
753
754 kunmap_atomic(pgaddr);
755 *val += ncpy;
756 }
757 *size -= ncpy;
758 cs->len -= ncpy;
759 cs->offset += ncpy;
760 return ncpy;
761 }
762
763 static int fuse_check_page(struct page *page)
764 {
765 if (page_mapcount(page) ||
766 page->mapping != NULL ||
767 page_count(page) != 1 ||
768 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
769 ~(1 << PG_locked |
770 1 << PG_referenced |
771 1 << PG_uptodate |
772 1 << PG_lru |
773 1 << PG_active |
774 1 << PG_reclaim))) {
775 pr_warn("trying to steal weird page\n");
776 pr_warn(" page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
777 return 1;
778 }
779 return 0;
780 }
781
782 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
783 {
784 int err;
785 struct page *oldpage = *pagep;
786 struct page *newpage;
787 struct pipe_buffer *buf = cs->pipebufs;
788
789 err = unlock_request(cs->req);
790 if (err)
791 return err;
792
793 fuse_copy_finish(cs);
794
795 err = pipe_buf_confirm(cs->pipe, buf);
796 if (err)
797 return err;
798
799 BUG_ON(!cs->nr_segs);
800 cs->currbuf = buf;
801 cs->len = buf->len;
802 cs->pipebufs++;
803 cs->nr_segs--;
804
805 if (cs->len != PAGE_SIZE)
806 goto out_fallback;
807
808 if (!pipe_buf_try_steal(cs->pipe, buf))
809 goto out_fallback;
810
811 newpage = buf->page;
812
813 if (!PageUptodate(newpage))
814 SetPageUptodate(newpage);
815
816 ClearPageMappedToDisk(newpage);
817
818 if (fuse_check_page(newpage) != 0)
819 goto out_fallback_unlock;
820
821 /*
822 * This is a new and locked page, it shouldn't be mapped or
823 * have any special flags on it
824 */
825 if (WARN_ON(page_mapped(oldpage)))
826 goto out_fallback_unlock;
827 if (WARN_ON(page_has_private(oldpage)))
828 goto out_fallback_unlock;
829 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
830 goto out_fallback_unlock;
831 if (WARN_ON(PageMlocked(oldpage)))
832 goto out_fallback_unlock;
833
834 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
835 if (err) {
836 unlock_page(newpage);
837 return err;
838 }
839
840 get_page(newpage);
841
842 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
843 lru_cache_add(newpage);
844
845 err = 0;
846 spin_lock(&cs->req->waitq.lock);
847 if (test_bit(FR_ABORTED, &cs->req->flags))
848 err = -ENOENT;
849 else
850 *pagep = newpage;
851 spin_unlock(&cs->req->waitq.lock);
852
853 if (err) {
854 unlock_page(newpage);
855 put_page(newpage);
856 return err;
857 }
858
859 unlock_page(oldpage);
860 put_page(oldpage);
861 cs->len = 0;
862
863 return 0;
864
865 out_fallback_unlock:
866 unlock_page(newpage);
867 out_fallback:
868 cs->pg = buf->page;
869 cs->offset = buf->offset;
870
871 err = lock_request(cs->req);
872 if (err)
873 return err;
874
875 return 1;
876 }
877
878 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
879 unsigned offset, unsigned count)
880 {
881 struct pipe_buffer *buf;
882 int err;
883
884 if (cs->nr_segs >= cs->pipe->max_usage)
885 return -EIO;
886
887 err = unlock_request(cs->req);
888 if (err)
889 return err;
890
891 fuse_copy_finish(cs);
892
893 buf = cs->pipebufs;
894 get_page(page);
895 buf->page = page;
896 buf->offset = offset;
897 buf->len = count;
898
899 cs->pipebufs++;
900 cs->nr_segs++;
901 cs->len = 0;
902
903 return 0;
904 }
905
906 /*
907 * Copy a page in the request to/from the userspace buffer. Must be
908 * done atomically
909 */
910 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
911 unsigned offset, unsigned count, int zeroing)
912 {
913 int err;
914 struct page *page = *pagep;
915
916 if (page && zeroing && count < PAGE_SIZE)
917 clear_highpage(page);
918
919 while (count) {
920 if (cs->write && cs->pipebufs && page) {
921 return fuse_ref_page(cs, page, offset, count);
922 } else if (!cs->len) {
923 if (cs->move_pages && page &&
924 offset == 0 && count == PAGE_SIZE) {
925 err = fuse_try_move_page(cs, pagep);
926 if (err <= 0)
927 return err;
928 } else {
929 err = fuse_copy_fill(cs);
930 if (err)
931 return err;
932 }
933 }
934 if (page) {
935 void *mapaddr = kmap_atomic(page);
936 void *buf = mapaddr + offset;
937 offset += fuse_copy_do(cs, &buf, &count);
938 kunmap_atomic(mapaddr);
939 } else
940 offset += fuse_copy_do(cs, NULL, &count);
941 }
942 if (page && !cs->write)
943 flush_dcache_page(page);
944 return 0;
945 }
946
947 /* Copy pages in the request to/from userspace buffer */
948 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
949 int zeroing)
950 {
951 unsigned i;
952 struct fuse_req *req = cs->req;
953 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
954
955
956 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
957 int err;
958 unsigned int offset = ap->descs[i].offset;
959 unsigned int count = min(nbytes, ap->descs[i].length);
960
961 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
962 if (err)
963 return err;
964
965 nbytes -= count;
966 }
967 return 0;
968 }
969
970 /* Copy a single argument in the request to/from userspace buffer */
971 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
972 {
973 while (size) {
974 if (!cs->len) {
975 int err = fuse_copy_fill(cs);
976 if (err)
977 return err;
978 }
979 fuse_copy_do(cs, &val, &size);
980 }
981 return 0;
982 }
983
984 /* Copy request arguments to/from userspace buffer */
985 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
986 unsigned argpages, struct fuse_arg *args,
987 int zeroing)
988 {
989 int err = 0;
990 unsigned i;
991
992 for (i = 0; !err && i < numargs; i++) {
993 struct fuse_arg *arg = &args[i];
994 if (i == numargs - 1 && argpages)
995 err = fuse_copy_pages(cs, arg->size, zeroing);
996 else
997 err = fuse_copy_one(cs, arg->value, arg->size);
998 }
999 return err;
1000 }
1001
1002 static int forget_pending(struct fuse_iqueue *fiq)
1003 {
1004 return fiq->forget_list_head.next != NULL;
1005 }
1006
1007 static int request_pending(struct fuse_iqueue *fiq)
1008 {
1009 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1010 forget_pending(fiq);
1011 }
1012
1013 /*
1014 * Transfer an interrupt request to userspace
1015 *
1016 * Unlike other requests this is assembled on demand, without a need
1017 * to allocate a separate fuse_req structure.
1018 *
1019 * Called with fiq->lock held, releases it
1020 */
1021 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1022 struct fuse_copy_state *cs,
1023 size_t nbytes, struct fuse_req *req)
1024 __releases(fiq->lock)
1025 {
1026 struct fuse_in_header ih;
1027 struct fuse_interrupt_in arg;
1028 unsigned reqsize = sizeof(ih) + sizeof(arg);
1029 int err;
1030
1031 list_del_init(&req->intr_entry);
1032 memset(&ih, 0, sizeof(ih));
1033 memset(&arg, 0, sizeof(arg));
1034 ih.len = reqsize;
1035 ih.opcode = FUSE_INTERRUPT;
1036 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1037 arg.unique = req->in.h.unique;
1038
1039 spin_unlock(&fiq->lock);
1040 if (nbytes < reqsize)
1041 return -EINVAL;
1042
1043 err = fuse_copy_one(cs, &ih, sizeof(ih));
1044 if (!err)
1045 err = fuse_copy_one(cs, &arg, sizeof(arg));
1046 fuse_copy_finish(cs);
1047
1048 return err ? err : reqsize;
1049 }
1050
1051 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1052 unsigned int max,
1053 unsigned int *countp)
1054 {
1055 struct fuse_forget_link *head = fiq->forget_list_head.next;
1056 struct fuse_forget_link **newhead = &head;
1057 unsigned count;
1058
1059 for (count = 0; *newhead != NULL && count < max; count++)
1060 newhead = &(*newhead)->next;
1061
1062 fiq->forget_list_head.next = *newhead;
1063 *newhead = NULL;
1064 if (fiq->forget_list_head.next == NULL)
1065 fiq->forget_list_tail = &fiq->forget_list_head;
1066
1067 if (countp != NULL)
1068 *countp = count;
1069
1070 return head;
1071 }
1072 EXPORT_SYMBOL(fuse_dequeue_forget);
1073
1074 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1075 struct fuse_copy_state *cs,
1076 size_t nbytes)
1077 __releases(fiq->lock)
1078 {
1079 int err;
1080 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1081 struct fuse_forget_in arg = {
1082 .nlookup = forget->forget_one.nlookup,
1083 };
1084 struct fuse_in_header ih = {
1085 .opcode = FUSE_FORGET,
1086 .nodeid = forget->forget_one.nodeid,
1087 .unique = fuse_get_unique(fiq),
1088 .len = sizeof(ih) + sizeof(arg),
1089 };
1090
1091 spin_unlock(&fiq->lock);
1092 kfree(forget);
1093 if (nbytes < ih.len)
1094 return -EINVAL;
1095
1096 err = fuse_copy_one(cs, &ih, sizeof(ih));
1097 if (!err)
1098 err = fuse_copy_one(cs, &arg, sizeof(arg));
1099 fuse_copy_finish(cs);
1100
1101 if (err)
1102 return err;
1103
1104 return ih.len;
1105 }
1106
1107 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1108 struct fuse_copy_state *cs, size_t nbytes)
1109 __releases(fiq->lock)
1110 {
1111 int err;
1112 unsigned max_forgets;
1113 unsigned count;
1114 struct fuse_forget_link *head;
1115 struct fuse_batch_forget_in arg = { .count = 0 };
1116 struct fuse_in_header ih = {
1117 .opcode = FUSE_BATCH_FORGET,
1118 .unique = fuse_get_unique(fiq),
1119 .len = sizeof(ih) + sizeof(arg),
1120 };
1121
1122 if (nbytes < ih.len) {
1123 spin_unlock(&fiq->lock);
1124 return -EINVAL;
1125 }
1126
1127 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1128 head = fuse_dequeue_forget(fiq, max_forgets, &count);
1129 spin_unlock(&fiq->lock);
1130
1131 arg.count = count;
1132 ih.len += count * sizeof(struct fuse_forget_one);
1133 err = fuse_copy_one(cs, &ih, sizeof(ih));
1134 if (!err)
1135 err = fuse_copy_one(cs, &arg, sizeof(arg));
1136
1137 while (head) {
1138 struct fuse_forget_link *forget = head;
1139
1140 if (!err) {
1141 err = fuse_copy_one(cs, &forget->forget_one,
1142 sizeof(forget->forget_one));
1143 }
1144 head = forget->next;
1145 kfree(forget);
1146 }
1147
1148 fuse_copy_finish(cs);
1149
1150 if (err)
1151 return err;
1152
1153 return ih.len;
1154 }
1155
1156 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1157 struct fuse_copy_state *cs,
1158 size_t nbytes)
1159 __releases(fiq->lock)
1160 {
1161 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1162 return fuse_read_single_forget(fiq, cs, nbytes);
1163 else
1164 return fuse_read_batch_forget(fiq, cs, nbytes);
1165 }
1166
1167 /*
1168 * Read a single request into the userspace filesystem's buffer. This
1169 * function waits until a request is available, then removes it from
1170 * the pending list and copies request data to userspace buffer. If
1171 * no reply is needed (FORGET) or request has been aborted or there
1172 * was an error during the copying then it's finished by calling
1173 * fuse_request_end(). Otherwise add it to the processing list, and set
1174 * the 'sent' flag.
1175 */
1176 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1177 struct fuse_copy_state *cs, size_t nbytes)
1178 {
1179 ssize_t err;
1180 struct fuse_conn *fc = fud->fc;
1181 struct fuse_iqueue *fiq = &fc->iq;
1182 struct fuse_pqueue *fpq = &fud->pq;
1183 struct fuse_req *req;
1184 struct fuse_args *args;
1185 unsigned reqsize;
1186 unsigned int hash;
1187
1188 /*
1189 * Require sane minimum read buffer - that has capacity for fixed part
1190 * of any request header + negotiated max_write room for data.
1191 *
1192 * Historically libfuse reserves 4K for fixed header room, but e.g.
1193 * GlusterFS reserves only 80 bytes
1194 *
1195 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1196 *
1197 * which is the absolute minimum any sane filesystem should be using
1198 * for header room.
1199 */
1200 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1201 sizeof(struct fuse_in_header) +
1202 sizeof(struct fuse_write_in) +
1203 fc->max_write))
1204 return -EINVAL;
1205
1206 restart:
1207 for (;;) {
1208 spin_lock(&fiq->lock);
1209 if (!fiq->connected || request_pending(fiq))
1210 break;
1211 spin_unlock(&fiq->lock);
1212
1213 if (file->f_flags & O_NONBLOCK)
1214 return -EAGAIN;
1215 err = wait_event_interruptible_exclusive(fiq->waitq,
1216 !fiq->connected || request_pending(fiq));
1217 if (err)
1218 return err;
1219 }
1220
1221 if (!fiq->connected) {
1222 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1223 goto err_unlock;
1224 }
1225
1226 if (!list_empty(&fiq->interrupts)) {
1227 req = list_entry(fiq->interrupts.next, struct fuse_req,
1228 intr_entry);
1229 return fuse_read_interrupt(fiq, cs, nbytes, req);
1230 }
1231
1232 if (forget_pending(fiq)) {
1233 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1234 return fuse_read_forget(fc, fiq, cs, nbytes);
1235
1236 if (fiq->forget_batch <= -8)
1237 fiq->forget_batch = 16;
1238 }
1239
1240 req = list_entry(fiq->pending.next, struct fuse_req, list);
1241 clear_bit(FR_PENDING, &req->flags);
1242 list_del_init(&req->list);
1243 spin_unlock(&fiq->lock);
1244
1245 args = req->args;
1246 reqsize = req->in.h.len;
1247
1248 /* If request is too large, reply with an error and restart the read */
1249 if (nbytes < reqsize) {
1250 req->out.h.error = -EIO;
1251 /* SETXATTR is special, since it may contain too large data */
1252 if (args->opcode == FUSE_SETXATTR)
1253 req->out.h.error = -E2BIG;
1254 fuse_request_end(fc, req);
1255 goto restart;
1256 }
1257 spin_lock(&fpq->lock);
1258 list_add(&req->list, &fpq->io);
1259 spin_unlock(&fpq->lock);
1260 cs->req = req;
1261 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1262 if (!err)
1263 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1264 (struct fuse_arg *) args->in_args, 0);
1265 fuse_copy_finish(cs);
1266 spin_lock(&fpq->lock);
1267 clear_bit(FR_LOCKED, &req->flags);
1268 if (!fpq->connected) {
1269 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1270 goto out_end;
1271 }
1272 if (err) {
1273 req->out.h.error = -EIO;
1274 goto out_end;
1275 }
1276 if (!test_bit(FR_ISREPLY, &req->flags)) {
1277 err = reqsize;
1278 goto out_end;
1279 }
1280 hash = fuse_req_hash(req->in.h.unique);
1281 list_move_tail(&req->list, &fpq->processing[hash]);
1282 __fuse_get_request(req);
1283 set_bit(FR_SENT, &req->flags);
1284 spin_unlock(&fpq->lock);
1285 /* matches barrier in request_wait_answer() */
1286 smp_mb__after_atomic();
1287 if (test_bit(FR_INTERRUPTED, &req->flags))
1288 queue_interrupt(fiq, req);
1289 fuse_put_request(fc, req);
1290
1291 return reqsize;
1292
1293 out_end:
1294 if (!test_bit(FR_PRIVATE, &req->flags))
1295 list_del_init(&req->list);
1296 spin_unlock(&fpq->lock);
1297 fuse_request_end(fc, req);
1298 return err;
1299
1300 err_unlock:
1301 spin_unlock(&fiq->lock);
1302 return err;
1303 }
1304
1305 static int fuse_dev_open(struct inode *inode, struct file *file)
1306 {
1307 /*
1308 * The fuse device's file's private_data is used to hold
1309 * the fuse_conn(ection) when it is mounted, and is used to
1310 * keep track of whether the file has been mounted already.
1311 */
1312 file->private_data = NULL;
1313 return 0;
1314 }
1315
1316 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1317 {
1318 struct fuse_copy_state cs;
1319 struct file *file = iocb->ki_filp;
1320 struct fuse_dev *fud = fuse_get_dev(file);
1321
1322 if (!fud)
1323 return -EPERM;
1324
1325 if (!iter_is_iovec(to))
1326 return -EINVAL;
1327
1328 fuse_copy_init(&cs, 1, to);
1329
1330 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1331 }
1332
1333 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1334 struct pipe_inode_info *pipe,
1335 size_t len, unsigned int flags)
1336 {
1337 int total, ret;
1338 int page_nr = 0;
1339 struct pipe_buffer *bufs;
1340 struct fuse_copy_state cs;
1341 struct fuse_dev *fud = fuse_get_dev(in);
1342
1343 if (!fud)
1344 return -EPERM;
1345
1346 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1347 GFP_KERNEL);
1348 if (!bufs)
1349 return -ENOMEM;
1350
1351 fuse_copy_init(&cs, 1, NULL);
1352 cs.pipebufs = bufs;
1353 cs.pipe = pipe;
1354 ret = fuse_dev_do_read(fud, in, &cs, len);
1355 if (ret < 0)
1356 goto out;
1357
1358 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1359 ret = -EIO;
1360 goto out;
1361 }
1362
1363 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1364 /*
1365 * Need to be careful about this. Having buf->ops in module
1366 * code can Oops if the buffer persists after module unload.
1367 */
1368 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1369 bufs[page_nr].flags = 0;
1370 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1371 if (unlikely(ret < 0))
1372 break;
1373 }
1374 if (total)
1375 ret = total;
1376 out:
1377 for (; page_nr < cs.nr_segs; page_nr++)
1378 put_page(bufs[page_nr].page);
1379
1380 kvfree(bufs);
1381 return ret;
1382 }
1383
1384 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1385 struct fuse_copy_state *cs)
1386 {
1387 struct fuse_notify_poll_wakeup_out outarg;
1388 int err = -EINVAL;
1389
1390 if (size != sizeof(outarg))
1391 goto err;
1392
1393 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1394 if (err)
1395 goto err;
1396
1397 fuse_copy_finish(cs);
1398 return fuse_notify_poll_wakeup(fc, &outarg);
1399
1400 err:
1401 fuse_copy_finish(cs);
1402 return err;
1403 }
1404
1405 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1406 struct fuse_copy_state *cs)
1407 {
1408 struct fuse_notify_inval_inode_out outarg;
1409 int err = -EINVAL;
1410
1411 if (size != sizeof(outarg))
1412 goto err;
1413
1414 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1415 if (err)
1416 goto err;
1417 fuse_copy_finish(cs);
1418
1419 down_read(&fc->killsb);
1420 err = -ENOENT;
1421 if (fc->sb) {
1422 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1423 outarg.off, outarg.len);
1424 }
1425 up_read(&fc->killsb);
1426 return err;
1427
1428 err:
1429 fuse_copy_finish(cs);
1430 return err;
1431 }
1432
1433 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1434 struct fuse_copy_state *cs)
1435 {
1436 struct fuse_notify_inval_entry_out outarg;
1437 int err = -ENOMEM;
1438 char *buf;
1439 struct qstr name;
1440
1441 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1442 if (!buf)
1443 goto err;
1444
1445 err = -EINVAL;
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
1453 err = -ENAMETOOLONG;
1454 if (outarg.namelen > FUSE_NAME_MAX)
1455 goto err;
1456
1457 err = -EINVAL;
1458 if (size != sizeof(outarg) + outarg.namelen + 1)
1459 goto err;
1460
1461 name.name = buf;
1462 name.len = outarg.namelen;
1463 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1464 if (err)
1465 goto err;
1466 fuse_copy_finish(cs);
1467 buf[outarg.namelen] = 0;
1468
1469 down_read(&fc->killsb);
1470 err = -ENOENT;
1471 if (fc->sb)
1472 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1473 up_read(&fc->killsb);
1474 kfree(buf);
1475 return err;
1476
1477 err:
1478 kfree(buf);
1479 fuse_copy_finish(cs);
1480 return err;
1481 }
1482
1483 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1484 struct fuse_copy_state *cs)
1485 {
1486 struct fuse_notify_delete_out outarg;
1487 int err = -ENOMEM;
1488 char *buf;
1489 struct qstr name;
1490
1491 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1492 if (!buf)
1493 goto err;
1494
1495 err = -EINVAL;
1496 if (size < sizeof(outarg))
1497 goto err;
1498
1499 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1500 if (err)
1501 goto err;
1502
1503 err = -ENAMETOOLONG;
1504 if (outarg.namelen > FUSE_NAME_MAX)
1505 goto err;
1506
1507 err = -EINVAL;
1508 if (size != sizeof(outarg) + outarg.namelen + 1)
1509 goto err;
1510
1511 name.name = buf;
1512 name.len = outarg.namelen;
1513 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1514 if (err)
1515 goto err;
1516 fuse_copy_finish(cs);
1517 buf[outarg.namelen] = 0;
1518
1519 down_read(&fc->killsb);
1520 err = -ENOENT;
1521 if (fc->sb)
1522 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1523 outarg.child, &name);
1524 up_read(&fc->killsb);
1525 kfree(buf);
1526 return err;
1527
1528 err:
1529 kfree(buf);
1530 fuse_copy_finish(cs);
1531 return err;
1532 }
1533
1534 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1535 struct fuse_copy_state *cs)
1536 {
1537 struct fuse_notify_store_out outarg;
1538 struct inode *inode;
1539 struct address_space *mapping;
1540 u64 nodeid;
1541 int err;
1542 pgoff_t index;
1543 unsigned int offset;
1544 unsigned int num;
1545 loff_t file_size;
1546 loff_t end;
1547
1548 err = -EINVAL;
1549 if (size < sizeof(outarg))
1550 goto out_finish;
1551
1552 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1553 if (err)
1554 goto out_finish;
1555
1556 err = -EINVAL;
1557 if (size - sizeof(outarg) != outarg.size)
1558 goto out_finish;
1559
1560 nodeid = outarg.nodeid;
1561
1562 down_read(&fc->killsb);
1563
1564 err = -ENOENT;
1565 if (!fc->sb)
1566 goto out_up_killsb;
1567
1568 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1569 if (!inode)
1570 goto out_up_killsb;
1571
1572 mapping = inode->i_mapping;
1573 index = outarg.offset >> PAGE_SHIFT;
1574 offset = outarg.offset & ~PAGE_MASK;
1575 file_size = i_size_read(inode);
1576 end = outarg.offset + outarg.size;
1577 if (end > file_size) {
1578 file_size = end;
1579 fuse_write_update_size(inode, file_size);
1580 }
1581
1582 num = outarg.size;
1583 while (num) {
1584 struct page *page;
1585 unsigned int this_num;
1586
1587 err = -ENOMEM;
1588 page = find_or_create_page(mapping, index,
1589 mapping_gfp_mask(mapping));
1590 if (!page)
1591 goto out_iput;
1592
1593 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1594 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1595 if (!err && offset == 0 &&
1596 (this_num == PAGE_SIZE || file_size == end))
1597 SetPageUptodate(page);
1598 unlock_page(page);
1599 put_page(page);
1600
1601 if (err)
1602 goto out_iput;
1603
1604 num -= this_num;
1605 offset = 0;
1606 index++;
1607 }
1608
1609 err = 0;
1610
1611 out_iput:
1612 iput(inode);
1613 out_up_killsb:
1614 up_read(&fc->killsb);
1615 out_finish:
1616 fuse_copy_finish(cs);
1617 return err;
1618 }
1619
1620 struct fuse_retrieve_args {
1621 struct fuse_args_pages ap;
1622 struct fuse_notify_retrieve_in inarg;
1623 };
1624
1625 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args,
1626 int error)
1627 {
1628 struct fuse_retrieve_args *ra =
1629 container_of(args, typeof(*ra), ap.args);
1630
1631 release_pages(ra->ap.pages, ra->ap.num_pages);
1632 kfree(ra);
1633 }
1634
1635 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1636 struct fuse_notify_retrieve_out *outarg)
1637 {
1638 int err;
1639 struct address_space *mapping = inode->i_mapping;
1640 pgoff_t index;
1641 loff_t file_size;
1642 unsigned int num;
1643 unsigned int offset;
1644 size_t total_len = 0;
1645 unsigned int num_pages;
1646 struct fuse_retrieve_args *ra;
1647 size_t args_size = sizeof(*ra);
1648 struct fuse_args_pages *ap;
1649 struct fuse_args *args;
1650
1651 offset = outarg->offset & ~PAGE_MASK;
1652 file_size = i_size_read(inode);
1653
1654 num = min(outarg->size, fc->max_write);
1655 if (outarg->offset > file_size)
1656 num = 0;
1657 else if (outarg->offset + num > file_size)
1658 num = file_size - outarg->offset;
1659
1660 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1661 num_pages = min(num_pages, fc->max_pages);
1662
1663 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1664
1665 ra = kzalloc(args_size, GFP_KERNEL);
1666 if (!ra)
1667 return -ENOMEM;
1668
1669 ap = &ra->ap;
1670 ap->pages = (void *) (ra + 1);
1671 ap->descs = (void *) (ap->pages + num_pages);
1672
1673 args = &ap->args;
1674 args->nodeid = outarg->nodeid;
1675 args->opcode = FUSE_NOTIFY_REPLY;
1676 args->in_numargs = 2;
1677 args->in_pages = true;
1678 args->end = fuse_retrieve_end;
1679
1680 index = outarg->offset >> PAGE_SHIFT;
1681
1682 while (num && ap->num_pages < num_pages) {
1683 struct page *page;
1684 unsigned int this_num;
1685
1686 page = find_get_page(mapping, index);
1687 if (!page)
1688 break;
1689
1690 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1691 ap->pages[ap->num_pages] = page;
1692 ap->descs[ap->num_pages].offset = offset;
1693 ap->descs[ap->num_pages].length = this_num;
1694 ap->num_pages++;
1695
1696 offset = 0;
1697 num -= this_num;
1698 total_len += this_num;
1699 index++;
1700 }
1701 ra->inarg.offset = outarg->offset;
1702 ra->inarg.size = total_len;
1703 args->in_args[0].size = sizeof(ra->inarg);
1704 args->in_args[0].value = &ra->inarg;
1705 args->in_args[1].size = total_len;
1706
1707 err = fuse_simple_notify_reply(fc, args, outarg->notify_unique);
1708 if (err)
1709 fuse_retrieve_end(fc, args, err);
1710
1711 return err;
1712 }
1713
1714 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1715 struct fuse_copy_state *cs)
1716 {
1717 struct fuse_notify_retrieve_out outarg;
1718 struct inode *inode;
1719 int err;
1720
1721 err = -EINVAL;
1722 if (size != sizeof(outarg))
1723 goto copy_finish;
1724
1725 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1726 if (err)
1727 goto copy_finish;
1728
1729 fuse_copy_finish(cs);
1730
1731 down_read(&fc->killsb);
1732 err = -ENOENT;
1733 if (fc->sb) {
1734 u64 nodeid = outarg.nodeid;
1735
1736 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1737 if (inode) {
1738 err = fuse_retrieve(fc, inode, &outarg);
1739 iput(inode);
1740 }
1741 }
1742 up_read(&fc->killsb);
1743
1744 return err;
1745
1746 copy_finish:
1747 fuse_copy_finish(cs);
1748 return err;
1749 }
1750
1751 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1752 unsigned int size, struct fuse_copy_state *cs)
1753 {
1754 /* Don't try to move pages (yet) */
1755 cs->move_pages = 0;
1756
1757 switch (code) {
1758 case FUSE_NOTIFY_POLL:
1759 return fuse_notify_poll(fc, size, cs);
1760
1761 case FUSE_NOTIFY_INVAL_INODE:
1762 return fuse_notify_inval_inode(fc, size, cs);
1763
1764 case FUSE_NOTIFY_INVAL_ENTRY:
1765 return fuse_notify_inval_entry(fc, size, cs);
1766
1767 case FUSE_NOTIFY_STORE:
1768 return fuse_notify_store(fc, size, cs);
1769
1770 case FUSE_NOTIFY_RETRIEVE:
1771 return fuse_notify_retrieve(fc, size, cs);
1772
1773 case FUSE_NOTIFY_DELETE:
1774 return fuse_notify_delete(fc, size, cs);
1775
1776 default:
1777 fuse_copy_finish(cs);
1778 return -EINVAL;
1779 }
1780 }
1781
1782 /* Look up request on processing list by unique ID */
1783 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1784 {
1785 unsigned int hash = fuse_req_hash(unique);
1786 struct fuse_req *req;
1787
1788 list_for_each_entry(req, &fpq->processing[hash], list) {
1789 if (req->in.h.unique == unique)
1790 return req;
1791 }
1792 return NULL;
1793 }
1794
1795 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1796 unsigned nbytes)
1797 {
1798 unsigned reqsize = sizeof(struct fuse_out_header);
1799
1800 reqsize += fuse_len_args(args->out_numargs, args->out_args);
1801
1802 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1803 return -EINVAL;
1804 else if (reqsize > nbytes) {
1805 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1806 unsigned diffsize = reqsize - nbytes;
1807
1808 if (diffsize > lastarg->size)
1809 return -EINVAL;
1810 lastarg->size -= diffsize;
1811 }
1812 return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1813 args->out_args, args->page_zeroing);
1814 }
1815
1816 /*
1817 * Write a single reply to a request. First the header is copied from
1818 * the write buffer. The request is then searched on the processing
1819 * list by the unique ID found in the header. If found, then remove
1820 * it from the list and copy the rest of the buffer to the request.
1821 * The request is finished by calling fuse_request_end().
1822 */
1823 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1824 struct fuse_copy_state *cs, size_t nbytes)
1825 {
1826 int err;
1827 struct fuse_conn *fc = fud->fc;
1828 struct fuse_pqueue *fpq = &fud->pq;
1829 struct fuse_req *req;
1830 struct fuse_out_header oh;
1831
1832 err = -EINVAL;
1833 if (nbytes < sizeof(struct fuse_out_header))
1834 goto out;
1835
1836 err = fuse_copy_one(cs, &oh, sizeof(oh));
1837 if (err)
1838 goto copy_finish;
1839
1840 err = -EINVAL;
1841 if (oh.len != nbytes)
1842 goto copy_finish;
1843
1844 /*
1845 * Zero oh.unique indicates unsolicited notification message
1846 * and error contains notification code.
1847 */
1848 if (!oh.unique) {
1849 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1850 goto out;
1851 }
1852
1853 err = -EINVAL;
1854 if (oh.error <= -1000 || oh.error > 0)
1855 goto copy_finish;
1856
1857 spin_lock(&fpq->lock);
1858 req = NULL;
1859 if (fpq->connected)
1860 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1861
1862 err = -ENOENT;
1863 if (!req) {
1864 spin_unlock(&fpq->lock);
1865 goto copy_finish;
1866 }
1867
1868 /* Is it an interrupt reply ID? */
1869 if (oh.unique & FUSE_INT_REQ_BIT) {
1870 __fuse_get_request(req);
1871 spin_unlock(&fpq->lock);
1872
1873 err = 0;
1874 if (nbytes != sizeof(struct fuse_out_header))
1875 err = -EINVAL;
1876 else if (oh.error == -ENOSYS)
1877 fc->no_interrupt = 1;
1878 else if (oh.error == -EAGAIN)
1879 err = queue_interrupt(&fc->iq, req);
1880
1881 fuse_put_request(fc, req);
1882
1883 goto copy_finish;
1884 }
1885
1886 clear_bit(FR_SENT, &req->flags);
1887 list_move(&req->list, &fpq->io);
1888 req->out.h = oh;
1889 set_bit(FR_LOCKED, &req->flags);
1890 spin_unlock(&fpq->lock);
1891 cs->req = req;
1892 if (!req->args->page_replace)
1893 cs->move_pages = 0;
1894
1895 if (oh.error)
1896 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1897 else
1898 err = copy_out_args(cs, req->args, nbytes);
1899 fuse_copy_finish(cs);
1900
1901 spin_lock(&fpq->lock);
1902 clear_bit(FR_LOCKED, &req->flags);
1903 if (!fpq->connected)
1904 err = -ENOENT;
1905 else if (err)
1906 req->out.h.error = -EIO;
1907 if (!test_bit(FR_PRIVATE, &req->flags))
1908 list_del_init(&req->list);
1909 spin_unlock(&fpq->lock);
1910
1911 fuse_request_end(fc, req);
1912 out:
1913 return err ? err : nbytes;
1914
1915 copy_finish:
1916 fuse_copy_finish(cs);
1917 goto out;
1918 }
1919
1920 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1921 {
1922 struct fuse_copy_state cs;
1923 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1924
1925 if (!fud)
1926 return -EPERM;
1927
1928 if (!iter_is_iovec(from))
1929 return -EINVAL;
1930
1931 fuse_copy_init(&cs, 0, from);
1932
1933 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1934 }
1935
1936 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1937 struct file *out, loff_t *ppos,
1938 size_t len, unsigned int flags)
1939 {
1940 unsigned int head, tail, mask, count;
1941 unsigned nbuf;
1942 unsigned idx;
1943 struct pipe_buffer *bufs;
1944 struct fuse_copy_state cs;
1945 struct fuse_dev *fud;
1946 size_t rem;
1947 ssize_t ret;
1948
1949 fud = fuse_get_dev(out);
1950 if (!fud)
1951 return -EPERM;
1952
1953 pipe_lock(pipe);
1954
1955 head = pipe->head;
1956 tail = pipe->tail;
1957 mask = pipe->ring_size - 1;
1958 count = head - tail;
1959
1960 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1961 if (!bufs) {
1962 pipe_unlock(pipe);
1963 return -ENOMEM;
1964 }
1965
1966 nbuf = 0;
1967 rem = 0;
1968 for (idx = tail; idx != head && rem < len; idx++)
1969 rem += pipe->bufs[idx & mask].len;
1970
1971 ret = -EINVAL;
1972 if (rem < len)
1973 goto out_free;
1974
1975 rem = len;
1976 while (rem) {
1977 struct pipe_buffer *ibuf;
1978 struct pipe_buffer *obuf;
1979
1980 BUG_ON(nbuf >= pipe->ring_size);
1981 BUG_ON(tail == head);
1982 ibuf = &pipe->bufs[tail & mask];
1983 obuf = &bufs[nbuf];
1984
1985 if (rem >= ibuf->len) {
1986 *obuf = *ibuf;
1987 ibuf->ops = NULL;
1988 tail++;
1989 pipe->tail = tail;
1990 } else {
1991 if (!pipe_buf_get(pipe, ibuf))
1992 goto out_free;
1993
1994 *obuf = *ibuf;
1995 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1996 obuf->len = rem;
1997 ibuf->offset += obuf->len;
1998 ibuf->len -= obuf->len;
1999 }
2000 nbuf++;
2001 rem -= obuf->len;
2002 }
2003 pipe_unlock(pipe);
2004
2005 fuse_copy_init(&cs, 0, NULL);
2006 cs.pipebufs = bufs;
2007 cs.nr_segs = nbuf;
2008 cs.pipe = pipe;
2009
2010 if (flags & SPLICE_F_MOVE)
2011 cs.move_pages = 1;
2012
2013 ret = fuse_dev_do_write(fud, &cs, len);
2014
2015 pipe_lock(pipe);
2016 out_free:
2017 for (idx = 0; idx < nbuf; idx++)
2018 pipe_buf_release(pipe, &bufs[idx]);
2019 pipe_unlock(pipe);
2020
2021 kvfree(bufs);
2022 return ret;
2023 }
2024
2025 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2026 {
2027 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2028 struct fuse_iqueue *fiq;
2029 struct fuse_dev *fud = fuse_get_dev(file);
2030
2031 if (!fud)
2032 return EPOLLERR;
2033
2034 fiq = &fud->fc->iq;
2035 poll_wait(file, &fiq->waitq, wait);
2036
2037 spin_lock(&fiq->lock);
2038 if (!fiq->connected)
2039 mask = EPOLLERR;
2040 else if (request_pending(fiq))
2041 mask |= EPOLLIN | EPOLLRDNORM;
2042 spin_unlock(&fiq->lock);
2043
2044 return mask;
2045 }
2046
2047 /* Abort all requests on the given list (pending or processing) */
2048 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2049 {
2050 while (!list_empty(head)) {
2051 struct fuse_req *req;
2052 req = list_entry(head->next, struct fuse_req, list);
2053 req->out.h.error = -ECONNABORTED;
2054 clear_bit(FR_SENT, &req->flags);
2055 list_del_init(&req->list);
2056 fuse_request_end(fc, req);
2057 }
2058 }
2059
2060 static void end_polls(struct fuse_conn *fc)
2061 {
2062 struct rb_node *p;
2063
2064 p = rb_first(&fc->polled_files);
2065
2066 while (p) {
2067 struct fuse_file *ff;
2068 ff = rb_entry(p, struct fuse_file, polled_node);
2069 wake_up_interruptible_all(&ff->poll_wait);
2070
2071 p = rb_next(p);
2072 }
2073 }
2074
2075 /*
2076 * Abort all requests.
2077 *
2078 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2079 * filesystem.
2080 *
2081 * The same effect is usually achievable through killing the filesystem daemon
2082 * and all users of the filesystem. The exception is the combination of an
2083 * asynchronous request and the tricky deadlock (see
2084 * Documentation/filesystems/fuse.rst).
2085 *
2086 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2087 * requests, they should be finished off immediately. Locked requests will be
2088 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2089 * requests. It is possible that some request will finish before we can. This
2090 * is OK, the request will in that case be removed from the list before we touch
2091 * it.
2092 */
2093 void fuse_abort_conn(struct fuse_conn *fc)
2094 {
2095 struct fuse_iqueue *fiq = &fc->iq;
2096
2097 spin_lock(&fc->lock);
2098 if (fc->connected) {
2099 struct fuse_dev *fud;
2100 struct fuse_req *req, *next;
2101 LIST_HEAD(to_end);
2102 unsigned int i;
2103
2104 /* Background queuing checks fc->connected under bg_lock */
2105 spin_lock(&fc->bg_lock);
2106 fc->connected = 0;
2107 spin_unlock(&fc->bg_lock);
2108
2109 fuse_set_initialized(fc);
2110 list_for_each_entry(fud, &fc->devices, entry) {
2111 struct fuse_pqueue *fpq = &fud->pq;
2112
2113 spin_lock(&fpq->lock);
2114 fpq->connected = 0;
2115 list_for_each_entry_safe(req, next, &fpq->io, list) {
2116 req->out.h.error = -ECONNABORTED;
2117 spin_lock(&req->waitq.lock);
2118 set_bit(FR_ABORTED, &req->flags);
2119 if (!test_bit(FR_LOCKED, &req->flags)) {
2120 set_bit(FR_PRIVATE, &req->flags);
2121 __fuse_get_request(req);
2122 list_move(&req->list, &to_end);
2123 }
2124 spin_unlock(&req->waitq.lock);
2125 }
2126 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2127 list_splice_tail_init(&fpq->processing[i],
2128 &to_end);
2129 spin_unlock(&fpq->lock);
2130 }
2131 spin_lock(&fc->bg_lock);
2132 fc->blocked = 0;
2133 fc->max_background = UINT_MAX;
2134 flush_bg_queue(fc);
2135 spin_unlock(&fc->bg_lock);
2136
2137 spin_lock(&fiq->lock);
2138 fiq->connected = 0;
2139 list_for_each_entry(req, &fiq->pending, list)
2140 clear_bit(FR_PENDING, &req->flags);
2141 list_splice_tail_init(&fiq->pending, &to_end);
2142 while (forget_pending(fiq))
2143 kfree(fuse_dequeue_forget(fiq, 1, NULL));
2144 wake_up_all(&fiq->waitq);
2145 spin_unlock(&fiq->lock);
2146 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2147 end_polls(fc);
2148 wake_up_all(&fc->blocked_waitq);
2149 spin_unlock(&fc->lock);
2150
2151 end_requests(fc, &to_end);
2152 } else {
2153 spin_unlock(&fc->lock);
2154 }
2155 }
2156 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2157
2158 void fuse_wait_aborted(struct fuse_conn *fc)
2159 {
2160 /* matches implicit memory barrier in fuse_drop_waiting() */
2161 smp_mb();
2162 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2163 }
2164
2165 int fuse_dev_release(struct inode *inode, struct file *file)
2166 {
2167 struct fuse_dev *fud = fuse_get_dev(file);
2168
2169 if (fud) {
2170 struct fuse_conn *fc = fud->fc;
2171 struct fuse_pqueue *fpq = &fud->pq;
2172 LIST_HEAD(to_end);
2173 unsigned int i;
2174
2175 spin_lock(&fpq->lock);
2176 WARN_ON(!list_empty(&fpq->io));
2177 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2178 list_splice_init(&fpq->processing[i], &to_end);
2179 spin_unlock(&fpq->lock);
2180
2181 end_requests(fc, &to_end);
2182
2183 /* Are we the last open device? */
2184 if (atomic_dec_and_test(&fc->dev_count)) {
2185 WARN_ON(fc->iq.fasync != NULL);
2186 fuse_abort_conn(fc);
2187 }
2188 fuse_dev_free(fud);
2189 }
2190 return 0;
2191 }
2192 EXPORT_SYMBOL_GPL(fuse_dev_release);
2193
2194 static int fuse_dev_fasync(int fd, struct file *file, int on)
2195 {
2196 struct fuse_dev *fud = fuse_get_dev(file);
2197
2198 if (!fud)
2199 return -EPERM;
2200
2201 /* No locking - fasync_helper does its own locking */
2202 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2203 }
2204
2205 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2206 {
2207 struct fuse_dev *fud;
2208
2209 if (new->private_data)
2210 return -EINVAL;
2211
2212 fud = fuse_dev_alloc_install(fc);
2213 if (!fud)
2214 return -ENOMEM;
2215
2216 new->private_data = fud;
2217 atomic_inc(&fc->dev_count);
2218
2219 return 0;
2220 }
2221
2222 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2223 unsigned long arg)
2224 {
2225 int err = -ENOTTY;
2226
2227 if (cmd == FUSE_DEV_IOC_CLONE) {
2228 int oldfd;
2229
2230 err = -EFAULT;
2231 if (!get_user(oldfd, (__u32 __user *) arg)) {
2232 struct file *old = fget(oldfd);
2233
2234 err = -EINVAL;
2235 if (old) {
2236 struct fuse_dev *fud = NULL;
2237
2238 /*
2239 * Check against file->f_op because CUSE
2240 * uses the same ioctl handler.
2241 */
2242 if (old->f_op == file->f_op &&
2243 old->f_cred->user_ns == file->f_cred->user_ns)
2244 fud = fuse_get_dev(old);
2245
2246 if (fud) {
2247 mutex_lock(&fuse_mutex);
2248 err = fuse_device_clone(fud->fc, file);
2249 mutex_unlock(&fuse_mutex);
2250 }
2251 fput(old);
2252 }
2253 }
2254 }
2255 return err;
2256 }
2257
2258 const struct file_operations fuse_dev_operations = {
2259 .owner = THIS_MODULE,
2260 .open = fuse_dev_open,
2261 .llseek = no_llseek,
2262 .read_iter = fuse_dev_read,
2263 .splice_read = fuse_dev_splice_read,
2264 .write_iter = fuse_dev_write,
2265 .splice_write = fuse_dev_splice_write,
2266 .poll = fuse_dev_poll,
2267 .release = fuse_dev_release,
2268 .fasync = fuse_dev_fasync,
2269 .unlocked_ioctl = fuse_dev_ioctl,
2270 .compat_ioctl = compat_ptr_ioctl,
2271 };
2272 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2273
2274 static struct miscdevice fuse_miscdevice = {
2275 .minor = FUSE_MINOR,
2276 .name = "fuse",
2277 .fops = &fuse_dev_operations,
2278 };
2279
2280 int __init fuse_dev_init(void)
2281 {
2282 int err = -ENOMEM;
2283 fuse_req_cachep = kmem_cache_create("fuse_request",
2284 sizeof(struct fuse_req),
2285 0, 0, NULL);
2286 if (!fuse_req_cachep)
2287 goto out;
2288
2289 err = misc_register(&fuse_miscdevice);
2290 if (err)
2291 goto out_cache_clean;
2292
2293 return 0;
2294
2295 out_cache_clean:
2296 kmem_cache_destroy(fuse_req_cachep);
2297 out:
2298 return err;
2299 }
2300
2301 void fuse_dev_cleanup(void)
2302 {
2303 misc_deregister(&fuse_miscdevice);
2304 kmem_cache_destroy(fuse_req_cachep);
2305 }
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