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Linux 4.14.215
[linux/fpc-iii.git] / fs / fuse / dev.c
blobcfc19140f2a074b59d2d3bf2879f9c47aa08de07
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/sched/signal.h>
15 #include <linux/uio.h>
16 #include <linux/miscdevice.h>
17 #include <linux/pagemap.h>
18 #include <linux/file.h>
19 #include <linux/slab.h>
20 #include <linux/pipe_fs_i.h>
21 #include <linux/swap.h>
22 #include <linux/splice.h>
23 #include <linux/sched.h>
24
25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26 MODULE_ALIAS("devname:fuse");
27
28 static struct kmem_cache *fuse_req_cachep;
29
30 static struct fuse_dev *fuse_get_dev(struct file *file)
31 {
32 /*
33 * Lockless access is OK, because file->private data is set
34 * once during mount and is valid until the file is released.
35 */
36 return ACCESS_ONCE(file->private_data);
37 }
38
39 static void fuse_request_init(struct fuse_req *req, struct page **pages,
40 struct fuse_page_desc *page_descs,
41 unsigned npages)
42 {
43 memset(req, 0, sizeof(*req));
44 memset(pages, 0, sizeof(*pages) * npages);
45 memset(page_descs, 0, sizeof(*page_descs) * npages);
46 INIT_LIST_HEAD(&req->list);
47 INIT_LIST_HEAD(&req->intr_entry);
48 init_waitqueue_head(&req->waitq);
49 refcount_set(&req->count, 1);
50 req->pages = pages;
51 req->page_descs = page_descs;
52 req->max_pages = npages;
53 __set_bit(FR_PENDING, &req->flags);
54 }
55
56 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
57 {
58 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
59 if (req) {
60 struct page **pages;
61 struct fuse_page_desc *page_descs;
62
63 if (npages <= FUSE_REQ_INLINE_PAGES) {
64 pages = req->inline_pages;
65 page_descs = req->inline_page_descs;
66 } else {
67 pages = kmalloc(sizeof(struct page *) * npages, flags);
68 page_descs = kmalloc(sizeof(struct fuse_page_desc) *
69 npages, flags);
70 }
71
72 if (!pages || !page_descs) {
73 kfree(pages);
74 kfree(page_descs);
75 kmem_cache_free(fuse_req_cachep, req);
76 return NULL;
77 }
78
79 fuse_request_init(req, pages, page_descs, npages);
80 }
81 return req;
82 }
83
84 struct fuse_req *fuse_request_alloc(unsigned npages)
85 {
86 return __fuse_request_alloc(npages, GFP_KERNEL);
87 }
88 EXPORT_SYMBOL_GPL(fuse_request_alloc);
89
90 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
91 {
92 return __fuse_request_alloc(npages, GFP_NOFS);
93 }
94
95 void fuse_request_free(struct fuse_req *req)
96 {
97 if (req->pages != req->inline_pages) {
98 kfree(req->pages);
99 kfree(req->page_descs);
100 }
101 kmem_cache_free(fuse_req_cachep, req);
102 }
103
104 void __fuse_get_request(struct fuse_req *req)
105 {
106 refcount_inc(&req->count);
107 }
108
109 /* Must be called with > 1 refcount */
110 static void __fuse_put_request(struct fuse_req *req)
111 {
112 refcount_dec(&req->count);
113 }
114
115 static void fuse_req_init_context(struct fuse_conn *fc, struct fuse_req *req)
116 {
117 req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
118 req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
119 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
120 }
121
122 void fuse_set_initialized(struct fuse_conn *fc)
123 {
124 /* Make sure stores before this are seen on another CPU */
125 smp_wmb();
126 fc->initialized = 1;
127 }
128
129 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
130 {
131 return !fc->initialized || (for_background && fc->blocked);
132 }
133
134 static void fuse_drop_waiting(struct fuse_conn *fc)
135 {
136 /*
137 * lockess check of fc->connected is okay, because atomic_dec_and_test()
138 * provides a memory barrier mached with the one in fuse_wait_aborted()
139 * to ensure no wake-up is missed.
140 */
141 if (atomic_dec_and_test(&fc->num_waiting) &&
142 !READ_ONCE(fc->connected)) {
143 /* wake up aborters */
144 wake_up_all(&fc->blocked_waitq);
145 }
146 }
147
148 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
149 bool for_background)
150 {
151 struct fuse_req *req;
152 int err;
153 atomic_inc(&fc->num_waiting);
154
155 if (fuse_block_alloc(fc, for_background)) {
156 err = -EINTR;
157 if (wait_event_killable_exclusive(fc->blocked_waitq,
158 !fuse_block_alloc(fc, for_background)))
159 goto out;
160 }
161 /* Matches smp_wmb() in fuse_set_initialized() */
162 smp_rmb();
163
164 err = -ENOTCONN;
165 if (!fc->connected)
166 goto out;
167
168 err = -ECONNREFUSED;
169 if (fc->conn_error)
170 goto out;
171
172 req = fuse_request_alloc(npages);
173 err = -ENOMEM;
174 if (!req) {
175 if (for_background)
176 wake_up(&fc->blocked_waitq);
177 goto out;
178 }
179
180 fuse_req_init_context(fc, req);
181 __set_bit(FR_WAITING, &req->flags);
182 if (for_background)
183 __set_bit(FR_BACKGROUND, &req->flags);
184
185 return req;
186
187 out:
188 fuse_drop_waiting(fc);
189 return ERR_PTR(err);
190 }
191
192 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
193 {
194 return __fuse_get_req(fc, npages, false);
195 }
196 EXPORT_SYMBOL_GPL(fuse_get_req);
197
198 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
199 unsigned npages)
200 {
201 return __fuse_get_req(fc, npages, true);
202 }
203 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
204
205 /*
206 * Return request in fuse_file->reserved_req. However that may
207 * currently be in use. If that is the case, wait for it to become
208 * available.
209 */
210 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
211 struct file *file)
212 {
213 struct fuse_req *req = NULL;
214 struct fuse_file *ff = file->private_data;
215
216 do {
217 wait_event(fc->reserved_req_waitq, ff->reserved_req);
218 spin_lock(&fc->lock);
219 if (ff->reserved_req) {
220 req = ff->reserved_req;
221 ff->reserved_req = NULL;
222 req->stolen_file = get_file(file);
223 }
224 spin_unlock(&fc->lock);
225 } while (!req);
226
227 return req;
228 }
229
230 /*
231 * Put stolen request back into fuse_file->reserved_req
232 */
233 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
234 {
235 struct file *file = req->stolen_file;
236 struct fuse_file *ff = file->private_data;
237
238 spin_lock(&fc->lock);
239 fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
240 BUG_ON(ff->reserved_req);
241 ff->reserved_req = req;
242 wake_up_all(&fc->reserved_req_waitq);
243 spin_unlock(&fc->lock);
244 fput(file);
245 }
246
247 /*
248 * Gets a requests for a file operation, always succeeds
249 *
250 * This is used for sending the FLUSH request, which must get to
251 * userspace, due to POSIX locks which may need to be unlocked.
252 *
253 * If allocation fails due to OOM, use the reserved request in
254 * fuse_file.
255 *
256 * This is very unlikely to deadlock accidentally, since the
257 * filesystem should not have it's own file open. If deadlock is
258 * intentional, it can still be broken by "aborting" the filesystem.
259 */
260 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
261 struct file *file)
262 {
263 struct fuse_req *req;
264
265 atomic_inc(&fc->num_waiting);
266 wait_event(fc->blocked_waitq, fc->initialized);
267 /* Matches smp_wmb() in fuse_set_initialized() */
268 smp_rmb();
269 req = fuse_request_alloc(0);
270 if (!req)
271 req = get_reserved_req(fc, file);
272
273 fuse_req_init_context(fc, req);
274 __set_bit(FR_WAITING, &req->flags);
275 __clear_bit(FR_BACKGROUND, &req->flags);
276 return req;
277 }
278
279 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
280 {
281 if (refcount_dec_and_test(&req->count)) {
282 if (test_bit(FR_BACKGROUND, &req->flags)) {
283 /*
284 * We get here in the unlikely case that a background
285 * request was allocated but not sent
286 */
287 spin_lock(&fc->lock);
288 if (!fc->blocked)
289 wake_up(&fc->blocked_waitq);
290 spin_unlock(&fc->lock);
291 }
292
293 if (test_bit(FR_WAITING, &req->flags)) {
294 __clear_bit(FR_WAITING, &req->flags);
295 fuse_drop_waiting(fc);
296 }
297
298 if (req->stolen_file)
299 put_reserved_req(fc, req);
300 else
301 fuse_request_free(req);
302 }
303 }
304 EXPORT_SYMBOL_GPL(fuse_put_request);
305
306 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
307 {
308 unsigned nbytes = 0;
309 unsigned i;
310
311 for (i = 0; i < numargs; i++)
312 nbytes += args[i].size;
313
314 return nbytes;
315 }
316
317 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
318 {
319 return ++fiq->reqctr;
320 }
321
322 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
323 {
324 req->in.h.len = sizeof(struct fuse_in_header) +
325 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
326 list_add_tail(&req->list, &fiq->pending);
327 wake_up_locked(&fiq->waitq);
328 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
329 }
330
331 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
332 u64 nodeid, u64 nlookup)
333 {
334 struct fuse_iqueue *fiq = &fc->iq;
335
336 forget->forget_one.nodeid = nodeid;
337 forget->forget_one.nlookup = nlookup;
338
339 spin_lock(&fiq->waitq.lock);
340 if (fiq->connected) {
341 fiq->forget_list_tail->next = forget;
342 fiq->forget_list_tail = forget;
343 wake_up_locked(&fiq->waitq);
344 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
345 } else {
346 kfree(forget);
347 }
348 spin_unlock(&fiq->waitq.lock);
349 }
350
351 static void flush_bg_queue(struct fuse_conn *fc)
352 {
353 while (fc->active_background < fc->max_background &&
354 !list_empty(&fc->bg_queue)) {
355 struct fuse_req *req;
356 struct fuse_iqueue *fiq = &fc->iq;
357
358 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
359 list_del(&req->list);
360 fc->active_background++;
361 spin_lock(&fiq->waitq.lock);
362 req->in.h.unique = fuse_get_unique(fiq);
363 queue_request(fiq, req);
364 spin_unlock(&fiq->waitq.lock);
365 }
366 }
367
368 /*
369 * This function is called when a request is finished. Either a reply
370 * has arrived or it was aborted (and not yet sent) or some error
371 * occurred during communication with userspace, or the device file
372 * was closed. The requester thread is woken up (if still waiting),
373 * the 'end' callback is called if given, else the reference to the
374 * request is released
375 */
376 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
377 {
378 struct fuse_iqueue *fiq = &fc->iq;
379
380 if (test_and_set_bit(FR_FINISHED, &req->flags))
381 goto put_request;
382
383 spin_lock(&fiq->waitq.lock);
384 list_del_init(&req->intr_entry);
385 spin_unlock(&fiq->waitq.lock);
386 WARN_ON(test_bit(FR_PENDING, &req->flags));
387 WARN_ON(test_bit(FR_SENT, &req->flags));
388 if (test_bit(FR_BACKGROUND, &req->flags)) {
389 spin_lock(&fc->lock);
390 clear_bit(FR_BACKGROUND, &req->flags);
391 if (fc->num_background == fc->max_background) {
392 fc->blocked = 0;
393 wake_up(&fc->blocked_waitq);
394 } else if (!fc->blocked) {
395 /*
396 * Wake up next waiter, if any. It's okay to use
397 * waitqueue_active(), as we've already synced up
398 * fc->blocked with waiters with the wake_up() call
399 * above.
400 */
401 if (waitqueue_active(&fc->blocked_waitq))
402 wake_up(&fc->blocked_waitq);
403 }
404
405 if (fc->num_background == fc->congestion_threshold && fc->sb) {
406 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
407 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
408 }
409 fc->num_background--;
410 fc->active_background--;
411 flush_bg_queue(fc);
412 spin_unlock(&fc->lock);
413 }
414 wake_up(&req->waitq);
415 if (req->end)
416 req->end(fc, req);
417 put_request:
418 fuse_put_request(fc, req);
419 }
420
421 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
422 {
423 spin_lock(&fiq->waitq.lock);
424 if (test_bit(FR_FINISHED, &req->flags)) {
425 spin_unlock(&fiq->waitq.lock);
426 return;
427 }
428 if (list_empty(&req->intr_entry)) {
429 list_add_tail(&req->intr_entry, &fiq->interrupts);
430 wake_up_locked(&fiq->waitq);
431 }
432 spin_unlock(&fiq->waitq.lock);
433 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
434 }
435
436 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
437 {
438 struct fuse_iqueue *fiq = &fc->iq;
439 int err;
440
441 if (!fc->no_interrupt) {
442 /* Any signal may interrupt this */
443 err = wait_event_interruptible(req->waitq,
444 test_bit(FR_FINISHED, &req->flags));
445 if (!err)
446 return;
447
448 set_bit(FR_INTERRUPTED, &req->flags);
449 /* matches barrier in fuse_dev_do_read() */
450 smp_mb__after_atomic();
451 if (test_bit(FR_SENT, &req->flags))
452 queue_interrupt(fiq, req);
453 }
454
455 if (!test_bit(FR_FORCE, &req->flags)) {
456 /* Only fatal signals may interrupt this */
457 err = wait_event_killable(req->waitq,
458 test_bit(FR_FINISHED, &req->flags));
459 if (!err)
460 return;
461
462 spin_lock(&fiq->waitq.lock);
463 /* Request is not yet in userspace, bail out */
464 if (test_bit(FR_PENDING, &req->flags)) {
465 list_del(&req->list);
466 spin_unlock(&fiq->waitq.lock);
467 __fuse_put_request(req);
468 req->out.h.error = -EINTR;
469 return;
470 }
471 spin_unlock(&fiq->waitq.lock);
472 }
473
474 /*
475 * Either request is already in userspace, or it was forced.
476 * Wait it out.
477 */
478 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
479 }
480
481 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
482 {
483 struct fuse_iqueue *fiq = &fc->iq;
484
485 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
486 spin_lock(&fiq->waitq.lock);
487 if (!fiq->connected) {
488 spin_unlock(&fiq->waitq.lock);
489 req->out.h.error = -ENOTCONN;
490 } else {
491 req->in.h.unique = fuse_get_unique(fiq);
492 queue_request(fiq, req);
493 /* acquire extra reference, since request is still needed
494 after request_end() */
495 __fuse_get_request(req);
496 spin_unlock(&fiq->waitq.lock);
497
498 request_wait_answer(fc, req);
499 /* Pairs with smp_wmb() in request_end() */
500 smp_rmb();
501 }
502 }
503
504 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
505 {
506 __set_bit(FR_ISREPLY, &req->flags);
507 if (!test_bit(FR_WAITING, &req->flags)) {
508 __set_bit(FR_WAITING, &req->flags);
509 atomic_inc(&fc->num_waiting);
510 }
511 __fuse_request_send(fc, req);
512 }
513 EXPORT_SYMBOL_GPL(fuse_request_send);
514
515 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
516 {
517 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
518 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
519
520 if (fc->minor < 9) {
521 switch (args->in.h.opcode) {
522 case FUSE_LOOKUP:
523 case FUSE_CREATE:
524 case FUSE_MKNOD:
525 case FUSE_MKDIR:
526 case FUSE_SYMLINK:
527 case FUSE_LINK:
528 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
529 break;
530 case FUSE_GETATTR:
531 case FUSE_SETATTR:
532 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
533 break;
534 }
535 }
536 if (fc->minor < 12) {
537 switch (args->in.h.opcode) {
538 case FUSE_CREATE:
539 args->in.args[0].size = sizeof(struct fuse_open_in);
540 break;
541 case FUSE_MKNOD:
542 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
543 break;
544 }
545 }
546 }
547
548 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
549 {
550 struct fuse_req *req;
551 ssize_t ret;
552
553 req = fuse_get_req(fc, 0);
554 if (IS_ERR(req))
555 return PTR_ERR(req);
556
557 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
558 fuse_adjust_compat(fc, args);
559
560 req->in.h.opcode = args->in.h.opcode;
561 req->in.h.nodeid = args->in.h.nodeid;
562 req->in.numargs = args->in.numargs;
563 memcpy(req->in.args, args->in.args,
564 args->in.numargs * sizeof(struct fuse_in_arg));
565 req->out.argvar = args->out.argvar;
566 req->out.numargs = args->out.numargs;
567 memcpy(req->out.args, args->out.args,
568 args->out.numargs * sizeof(struct fuse_arg));
569 fuse_request_send(fc, req);
570 ret = req->out.h.error;
571 if (!ret && args->out.argvar) {
572 BUG_ON(args->out.numargs != 1);
573 ret = req->out.args[0].size;
574 }
575 fuse_put_request(fc, req);
576
577 return ret;
578 }
579
580 /*
581 * Called under fc->lock
582 *
583 * fc->connected must have been checked previously
584 */
585 void fuse_request_send_background_locked(struct fuse_conn *fc,
586 struct fuse_req *req)
587 {
588 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
589 if (!test_bit(FR_WAITING, &req->flags)) {
590 __set_bit(FR_WAITING, &req->flags);
591 atomic_inc(&fc->num_waiting);
592 }
593 __set_bit(FR_ISREPLY, &req->flags);
594 fc->num_background++;
595 if (fc->num_background == fc->max_background)
596 fc->blocked = 1;
597 if (fc->num_background == fc->congestion_threshold && fc->sb) {
598 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
599 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
600 }
601 list_add_tail(&req->list, &fc->bg_queue);
602 flush_bg_queue(fc);
603 }
604
605 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
606 {
607 BUG_ON(!req->end);
608 spin_lock(&fc->lock);
609 if (fc->connected) {
610 fuse_request_send_background_locked(fc, req);
611 spin_unlock(&fc->lock);
612 } else {
613 spin_unlock(&fc->lock);
614 req->out.h.error = -ENOTCONN;
615 req->end(fc, req);
616 fuse_put_request(fc, req);
617 }
618 }
619 EXPORT_SYMBOL_GPL(fuse_request_send_background);
620
621 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
622 struct fuse_req *req, u64 unique)
623 {
624 int err = -ENODEV;
625 struct fuse_iqueue *fiq = &fc->iq;
626
627 __clear_bit(FR_ISREPLY, &req->flags);
628 req->in.h.unique = unique;
629 spin_lock(&fiq->waitq.lock);
630 if (fiq->connected) {
631 queue_request(fiq, req);
632 err = 0;
633 }
634 spin_unlock(&fiq->waitq.lock);
635
636 return err;
637 }
638
639 void fuse_force_forget(struct file *file, u64 nodeid)
640 {
641 struct inode *inode = file_inode(file);
642 struct fuse_conn *fc = get_fuse_conn(inode);
643 struct fuse_req *req;
644 struct fuse_forget_in inarg;
645
646 memset(&inarg, 0, sizeof(inarg));
647 inarg.nlookup = 1;
648 req = fuse_get_req_nofail_nopages(fc, file);
649 req->in.h.opcode = FUSE_FORGET;
650 req->in.h.nodeid = nodeid;
651 req->in.numargs = 1;
652 req->in.args[0].size = sizeof(inarg);
653 req->in.args[0].value = &inarg;
654 __clear_bit(FR_ISREPLY, &req->flags);
655 __fuse_request_send(fc, req);
656 /* ignore errors */
657 fuse_put_request(fc, req);
658 }
659
660 /*
661 * Lock the request. Up to the next unlock_request() there mustn't be
662 * anything that could cause a page-fault. If the request was already
663 * aborted bail out.
664 */
665 static int lock_request(struct fuse_req *req)
666 {
667 int err = 0;
668 if (req) {
669 spin_lock(&req->waitq.lock);
670 if (test_bit(FR_ABORTED, &req->flags))
671 err = -ENOENT;
672 else
673 set_bit(FR_LOCKED, &req->flags);
674 spin_unlock(&req->waitq.lock);
675 }
676 return err;
677 }
678
679 /*
680 * Unlock request. If it was aborted while locked, caller is responsible
681 * for unlocking and ending the request.
682 */
683 static int unlock_request(struct fuse_req *req)
684 {
685 int err = 0;
686 if (req) {
687 spin_lock(&req->waitq.lock);
688 if (test_bit(FR_ABORTED, &req->flags))
689 err = -ENOENT;
690 else
691 clear_bit(FR_LOCKED, &req->flags);
692 spin_unlock(&req->waitq.lock);
693 }
694 return err;
695 }
696
697 struct fuse_copy_state {
698 int write;
699 struct fuse_req *req;
700 struct iov_iter *iter;
701 struct pipe_buffer *pipebufs;
702 struct pipe_buffer *currbuf;
703 struct pipe_inode_info *pipe;
704 unsigned long nr_segs;
705 struct page *pg;
706 unsigned len;
707 unsigned offset;
708 unsigned move_pages:1;
709 };
710
711 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
712 struct iov_iter *iter)
713 {
714 memset(cs, 0, sizeof(*cs));
715 cs->write = write;
716 cs->iter = iter;
717 }
718
719 /* Unmap and put previous page of userspace buffer */
720 static void fuse_copy_finish(struct fuse_copy_state *cs)
721 {
722 if (cs->currbuf) {
723 struct pipe_buffer *buf = cs->currbuf;
724
725 if (cs->write)
726 buf->len = PAGE_SIZE - cs->len;
727 cs->currbuf = NULL;
728 } else if (cs->pg) {
729 if (cs->write) {
730 flush_dcache_page(cs->pg);
731 set_page_dirty_lock(cs->pg);
732 }
733 put_page(cs->pg);
734 }
735 cs->pg = NULL;
736 }
737
738 /*
739 * Get another pagefull of userspace buffer, and map it to kernel
740 * address space, and lock request
741 */
742 static int fuse_copy_fill(struct fuse_copy_state *cs)
743 {
744 struct page *page;
745 int err;
746
747 err = unlock_request(cs->req);
748 if (err)
749 return err;
750
751 fuse_copy_finish(cs);
752 if (cs->pipebufs) {
753 struct pipe_buffer *buf = cs->pipebufs;
754
755 if (!cs->write) {
756 err = pipe_buf_confirm(cs->pipe, buf);
757 if (err)
758 return err;
759
760 BUG_ON(!cs->nr_segs);
761 cs->currbuf = buf;
762 cs->pg = buf->page;
763 cs->offset = buf->offset;
764 cs->len = buf->len;
765 cs->pipebufs++;
766 cs->nr_segs--;
767 } else {
768 if (cs->nr_segs == cs->pipe->buffers)
769 return -EIO;
770
771 page = alloc_page(GFP_HIGHUSER);
772 if (!page)
773 return -ENOMEM;
774
775 buf->page = page;
776 buf->offset = 0;
777 buf->len = 0;
778
779 cs->currbuf = buf;
780 cs->pg = page;
781 cs->offset = 0;
782 cs->len = PAGE_SIZE;
783 cs->pipebufs++;
784 cs->nr_segs++;
785 }
786 } else {
787 size_t off;
788 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
789 if (err < 0)
790 return err;
791 BUG_ON(!err);
792 cs->len = err;
793 cs->offset = off;
794 cs->pg = page;
795 iov_iter_advance(cs->iter, err);
796 }
797
798 return lock_request(cs->req);
799 }
800
801 /* Do as much copy to/from userspace buffer as we can */
802 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
803 {
804 unsigned ncpy = min(*size, cs->len);
805 if (val) {
806 void *pgaddr = kmap_atomic(cs->pg);
807 void *buf = pgaddr + cs->offset;
808
809 if (cs->write)
810 memcpy(buf, *val, ncpy);
811 else
812 memcpy(*val, buf, ncpy);
813
814 kunmap_atomic(pgaddr);
815 *val += ncpy;
816 }
817 *size -= ncpy;
818 cs->len -= ncpy;
819 cs->offset += ncpy;
820 return ncpy;
821 }
822
823 static int fuse_check_page(struct page *page)
824 {
825 if (page_mapcount(page) ||
826 page->mapping != NULL ||
827 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
828 ~(1 << PG_locked |
829 1 << PG_referenced |
830 1 << PG_uptodate |
831 1 << PG_lru |
832 1 << PG_active |
833 1 << PG_reclaim))) {
834 printk(KERN_WARNING "fuse: trying to steal weird page\n");
835 printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
836 return 1;
837 }
838 return 0;
839 }
840
841 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
842 {
843 int err;
844 struct page *oldpage = *pagep;
845 struct page *newpage;
846 struct pipe_buffer *buf = cs->pipebufs;
847
848 get_page(oldpage);
849 err = unlock_request(cs->req);
850 if (err)
851 goto out_put_old;
852
853 fuse_copy_finish(cs);
854
855 err = pipe_buf_confirm(cs->pipe, buf);
856 if (err)
857 goto out_put_old;
858
859 BUG_ON(!cs->nr_segs);
860 cs->currbuf = buf;
861 cs->len = buf->len;
862 cs->pipebufs++;
863 cs->nr_segs--;
864
865 if (cs->len != PAGE_SIZE)
866 goto out_fallback;
867
868 if (pipe_buf_steal(cs->pipe, buf) != 0)
869 goto out_fallback;
870
871 newpage = buf->page;
872
873 if (!PageUptodate(newpage))
874 SetPageUptodate(newpage);
875
876 ClearPageMappedToDisk(newpage);
877
878 if (fuse_check_page(newpage) != 0)
879 goto out_fallback_unlock;
880
881 /*
882 * This is a new and locked page, it shouldn't be mapped or
883 * have any special flags on it
884 */
885 if (WARN_ON(page_mapped(oldpage)))
886 goto out_fallback_unlock;
887 if (WARN_ON(page_has_private(oldpage)))
888 goto out_fallback_unlock;
889 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
890 goto out_fallback_unlock;
891 if (WARN_ON(PageMlocked(oldpage)))
892 goto out_fallback_unlock;
893
894 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
895 if (err) {
896 unlock_page(newpage);
897 goto out_put_old;
898 }
899
900 get_page(newpage);
901
902 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
903 lru_cache_add_file(newpage);
904
905 err = 0;
906 spin_lock(&cs->req->waitq.lock);
907 if (test_bit(FR_ABORTED, &cs->req->flags))
908 err = -ENOENT;
909 else
910 *pagep = newpage;
911 spin_unlock(&cs->req->waitq.lock);
912
913 if (err) {
914 unlock_page(newpage);
915 put_page(newpage);
916 goto out_put_old;
917 }
918
919 unlock_page(oldpage);
920 /* Drop ref for ap->pages[] array */
921 put_page(oldpage);
922 cs->len = 0;
923
924 err = 0;
925 out_put_old:
926 /* Drop ref obtained in this function */
927 put_page(oldpage);
928 return err;
929
930 out_fallback_unlock:
931 unlock_page(newpage);
932 out_fallback:
933 cs->pg = buf->page;
934 cs->offset = buf->offset;
935
936 err = lock_request(cs->req);
937 if (!err)
938 err = 1;
939
940 goto out_put_old;
941 }
942
943 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
944 unsigned offset, unsigned count)
945 {
946 struct pipe_buffer *buf;
947 int err;
948
949 if (cs->nr_segs == cs->pipe->buffers)
950 return -EIO;
951
952 get_page(page);
953 err = unlock_request(cs->req);
954 if (err) {
955 put_page(page);
956 return err;
957 }
958
959 fuse_copy_finish(cs);
960
961 buf = cs->pipebufs;
962 buf->page = page;
963 buf->offset = offset;
964 buf->len = count;
965
966 cs->pipebufs++;
967 cs->nr_segs++;
968 cs->len = 0;
969
970 return 0;
971 }
972
973 /*
974 * Copy a page in the request to/from the userspace buffer. Must be
975 * done atomically
976 */
977 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
978 unsigned offset, unsigned count, int zeroing)
979 {
980 int err;
981 struct page *page = *pagep;
982
983 if (page && zeroing && count < PAGE_SIZE)
984 clear_highpage(page);
985
986 while (count) {
987 if (cs->write && cs->pipebufs && page) {
988 return fuse_ref_page(cs, page, offset, count);
989 } else if (!cs->len) {
990 if (cs->move_pages && page &&
991 offset == 0 && count == PAGE_SIZE) {
992 err = fuse_try_move_page(cs, pagep);
993 if (err <= 0)
994 return err;
995 } else {
996 err = fuse_copy_fill(cs);
997 if (err)
998 return err;
999 }
1000 }
1001 if (page) {
1002 void *mapaddr = kmap_atomic(page);
1003 void *buf = mapaddr + offset;
1004 offset += fuse_copy_do(cs, &buf, &count);
1005 kunmap_atomic(mapaddr);
1006 } else
1007 offset += fuse_copy_do(cs, NULL, &count);
1008 }
1009 if (page && !cs->write)
1010 flush_dcache_page(page);
1011 return 0;
1012 }
1013
1014 /* Copy pages in the request to/from userspace buffer */
1015 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1016 int zeroing)
1017 {
1018 unsigned i;
1019 struct fuse_req *req = cs->req;
1020
1021 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1022 int err;
1023 unsigned offset = req->page_descs[i].offset;
1024 unsigned count = min(nbytes, req->page_descs[i].length);
1025
1026 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1027 zeroing);
1028 if (err)
1029 return err;
1030
1031 nbytes -= count;
1032 }
1033 return 0;
1034 }
1035
1036 /* Copy a single argument in the request to/from userspace buffer */
1037 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1038 {
1039 while (size) {
1040 if (!cs->len) {
1041 int err = fuse_copy_fill(cs);
1042 if (err)
1043 return err;
1044 }
1045 fuse_copy_do(cs, &val, &size);
1046 }
1047 return 0;
1048 }
1049
1050 /* Copy request arguments to/from userspace buffer */
1051 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1052 unsigned argpages, struct fuse_arg *args,
1053 int zeroing)
1054 {
1055 int err = 0;
1056 unsigned i;
1057
1058 for (i = 0; !err && i < numargs; i++) {
1059 struct fuse_arg *arg = &args[i];
1060 if (i == numargs - 1 && argpages)
1061 err = fuse_copy_pages(cs, arg->size, zeroing);
1062 else
1063 err = fuse_copy_one(cs, arg->value, arg->size);
1064 }
1065 return err;
1066 }
1067
1068 static int forget_pending(struct fuse_iqueue *fiq)
1069 {
1070 return fiq->forget_list_head.next != NULL;
1071 }
1072
1073 static int request_pending(struct fuse_iqueue *fiq)
1074 {
1075 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1076 forget_pending(fiq);
1077 }
1078
1079 /*
1080 * Transfer an interrupt request to userspace
1081 *
1082 * Unlike other requests this is assembled on demand, without a need
1083 * to allocate a separate fuse_req structure.
1084 *
1085 * Called with fiq->waitq.lock held, releases it
1086 */
1087 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1088 struct fuse_copy_state *cs,
1089 size_t nbytes, struct fuse_req *req)
1090 __releases(fiq->waitq.lock)
1091 {
1092 struct fuse_in_header ih;
1093 struct fuse_interrupt_in arg;
1094 unsigned reqsize = sizeof(ih) + sizeof(arg);
1095 int err;
1096
1097 list_del_init(&req->intr_entry);
1098 req->intr_unique = fuse_get_unique(fiq);
1099 memset(&ih, 0, sizeof(ih));
1100 memset(&arg, 0, sizeof(arg));
1101 ih.len = reqsize;
1102 ih.opcode = FUSE_INTERRUPT;
1103 ih.unique = req->intr_unique;
1104 arg.unique = req->in.h.unique;
1105
1106 spin_unlock(&fiq->waitq.lock);
1107 if (nbytes < reqsize)
1108 return -EINVAL;
1109
1110 err = fuse_copy_one(cs, &ih, sizeof(ih));
1111 if (!err)
1112 err = fuse_copy_one(cs, &arg, sizeof(arg));
1113 fuse_copy_finish(cs);
1114
1115 return err ? err : reqsize;
1116 }
1117
1118 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1119 unsigned max,
1120 unsigned *countp)
1121 {
1122 struct fuse_forget_link *head = fiq->forget_list_head.next;
1123 struct fuse_forget_link **newhead = &head;
1124 unsigned count;
1125
1126 for (count = 0; *newhead != NULL && count < max; count++)
1127 newhead = &(*newhead)->next;
1128
1129 fiq->forget_list_head.next = *newhead;
1130 *newhead = NULL;
1131 if (fiq->forget_list_head.next == NULL)
1132 fiq->forget_list_tail = &fiq->forget_list_head;
1133
1134 if (countp != NULL)
1135 *countp = count;
1136
1137 return head;
1138 }
1139
1140 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1141 struct fuse_copy_state *cs,
1142 size_t nbytes)
1143 __releases(fiq->waitq.lock)
1144 {
1145 int err;
1146 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1147 struct fuse_forget_in arg = {
1148 .nlookup = forget->forget_one.nlookup,
1149 };
1150 struct fuse_in_header ih = {
1151 .opcode = FUSE_FORGET,
1152 .nodeid = forget->forget_one.nodeid,
1153 .unique = fuse_get_unique(fiq),
1154 .len = sizeof(ih) + sizeof(arg),
1155 };
1156
1157 spin_unlock(&fiq->waitq.lock);
1158 kfree(forget);
1159 if (nbytes < ih.len)
1160 return -EINVAL;
1161
1162 err = fuse_copy_one(cs, &ih, sizeof(ih));
1163 if (!err)
1164 err = fuse_copy_one(cs, &arg, sizeof(arg));
1165 fuse_copy_finish(cs);
1166
1167 if (err)
1168 return err;
1169
1170 return ih.len;
1171 }
1172
1173 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1174 struct fuse_copy_state *cs, size_t nbytes)
1175 __releases(fiq->waitq.lock)
1176 {
1177 int err;
1178 unsigned max_forgets;
1179 unsigned count;
1180 struct fuse_forget_link *head;
1181 struct fuse_batch_forget_in arg = { .count = 0 };
1182 struct fuse_in_header ih = {
1183 .opcode = FUSE_BATCH_FORGET,
1184 .unique = fuse_get_unique(fiq),
1185 .len = sizeof(ih) + sizeof(arg),
1186 };
1187
1188 if (nbytes < ih.len) {
1189 spin_unlock(&fiq->waitq.lock);
1190 return -EINVAL;
1191 }
1192
1193 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1194 head = dequeue_forget(fiq, max_forgets, &count);
1195 spin_unlock(&fiq->waitq.lock);
1196
1197 arg.count = count;
1198 ih.len += count * sizeof(struct fuse_forget_one);
1199 err = fuse_copy_one(cs, &ih, sizeof(ih));
1200 if (!err)
1201 err = fuse_copy_one(cs, &arg, sizeof(arg));
1202
1203 while (head) {
1204 struct fuse_forget_link *forget = head;
1205
1206 if (!err) {
1207 err = fuse_copy_one(cs, &forget->forget_one,
1208 sizeof(forget->forget_one));
1209 }
1210 head = forget->next;
1211 kfree(forget);
1212 }
1213
1214 fuse_copy_finish(cs);
1215
1216 if (err)
1217 return err;
1218
1219 return ih.len;
1220 }
1221
1222 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1223 struct fuse_copy_state *cs,
1224 size_t nbytes)
1225 __releases(fiq->waitq.lock)
1226 {
1227 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1228 return fuse_read_single_forget(fiq, cs, nbytes);
1229 else
1230 return fuse_read_batch_forget(fiq, cs, nbytes);
1231 }
1232
1233 /*
1234 * Read a single request into the userspace filesystem's buffer. This
1235 * function waits until a request is available, then removes it from
1236 * the pending list and copies request data to userspace buffer. If
1237 * no reply is needed (FORGET) or request has been aborted or there
1238 * was an error during the copying then it's finished by calling
1239 * request_end(). Otherwise add it to the processing list, and set
1240 * the 'sent' flag.
1241 */
1242 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1243 struct fuse_copy_state *cs, size_t nbytes)
1244 {
1245 ssize_t err;
1246 struct fuse_conn *fc = fud->fc;
1247 struct fuse_iqueue *fiq = &fc->iq;
1248 struct fuse_pqueue *fpq = &fud->pq;
1249 struct fuse_req *req;
1250 struct fuse_in *in;
1251 unsigned reqsize;
1252
1253 restart:
1254 spin_lock(&fiq->waitq.lock);
1255 err = -EAGAIN;
1256 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1257 !request_pending(fiq))
1258 goto err_unlock;
1259
1260 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1261 !fiq->connected || request_pending(fiq));
1262 if (err)
1263 goto err_unlock;
1264
1265 err = -ENODEV;
1266 if (!fiq->connected)
1267 goto err_unlock;
1268
1269 if (!list_empty(&fiq->interrupts)) {
1270 req = list_entry(fiq->interrupts.next, struct fuse_req,
1271 intr_entry);
1272 return fuse_read_interrupt(fiq, cs, nbytes, req);
1273 }
1274
1275 if (forget_pending(fiq)) {
1276 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1277 return fuse_read_forget(fc, fiq, cs, nbytes);
1278
1279 if (fiq->forget_batch <= -8)
1280 fiq->forget_batch = 16;
1281 }
1282
1283 req = list_entry(fiq->pending.next, struct fuse_req, list);
1284 clear_bit(FR_PENDING, &req->flags);
1285 list_del_init(&req->list);
1286 spin_unlock(&fiq->waitq.lock);
1287
1288 in = &req->in;
1289 reqsize = in->h.len;
1290
1291 if (task_active_pid_ns(current) != fc->pid_ns) {
1292 rcu_read_lock();
1293 in->h.pid = pid_vnr(find_pid_ns(in->h.pid, fc->pid_ns));
1294 rcu_read_unlock();
1295 }
1296
1297 /* If request is too large, reply with an error and restart the read */
1298 if (nbytes < reqsize) {
1299 req->out.h.error = -EIO;
1300 /* SETXATTR is special, since it may contain too large data */
1301 if (in->h.opcode == FUSE_SETXATTR)
1302 req->out.h.error = -E2BIG;
1303 request_end(fc, req);
1304 goto restart;
1305 }
1306 spin_lock(&fpq->lock);
1307 list_add(&req->list, &fpq->io);
1308 spin_unlock(&fpq->lock);
1309 cs->req = req;
1310 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1311 if (!err)
1312 err = fuse_copy_args(cs, in->numargs, in->argpages,
1313 (struct fuse_arg *) in->args, 0);
1314 fuse_copy_finish(cs);
1315 spin_lock(&fpq->lock);
1316 clear_bit(FR_LOCKED, &req->flags);
1317 if (!fpq->connected) {
1318 err = -ENODEV;
1319 goto out_end;
1320 }
1321 if (err) {
1322 req->out.h.error = -EIO;
1323 goto out_end;
1324 }
1325 if (!test_bit(FR_ISREPLY, &req->flags)) {
1326 err = reqsize;
1327 goto out_end;
1328 }
1329 list_move_tail(&req->list, &fpq->processing);
1330 __fuse_get_request(req);
1331 set_bit(FR_SENT, &req->flags);
1332 spin_unlock(&fpq->lock);
1333 /* matches barrier in request_wait_answer() */
1334 smp_mb__after_atomic();
1335 if (test_bit(FR_INTERRUPTED, &req->flags))
1336 queue_interrupt(fiq, req);
1337 fuse_put_request(fc, req);
1338
1339 return reqsize;
1340
1341 out_end:
1342 if (!test_bit(FR_PRIVATE, &req->flags))
1343 list_del_init(&req->list);
1344 spin_unlock(&fpq->lock);
1345 request_end(fc, req);
1346 return err;
1347
1348 err_unlock:
1349 spin_unlock(&fiq->waitq.lock);
1350 return err;
1351 }
1352
1353 static int fuse_dev_open(struct inode *inode, struct file *file)
1354 {
1355 /*
1356 * The fuse device's file's private_data is used to hold
1357 * the fuse_conn(ection) when it is mounted, and is used to
1358 * keep track of whether the file has been mounted already.
1359 */
1360 file->private_data = NULL;
1361 return 0;
1362 }
1363
1364 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1365 {
1366 struct fuse_copy_state cs;
1367 struct file *file = iocb->ki_filp;
1368 struct fuse_dev *fud = fuse_get_dev(file);
1369
1370 if (!fud)
1371 return -EPERM;
1372
1373 if (!iter_is_iovec(to))
1374 return -EINVAL;
1375
1376 fuse_copy_init(&cs, 1, to);
1377
1378 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1379 }
1380
1381 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1382 struct pipe_inode_info *pipe,
1383 size_t len, unsigned int flags)
1384 {
1385 int total, ret;
1386 int page_nr = 0;
1387 struct pipe_buffer *bufs;
1388 struct fuse_copy_state cs;
1389 struct fuse_dev *fud = fuse_get_dev(in);
1390
1391 if (!fud)
1392 return -EPERM;
1393
1394 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1395 if (!bufs)
1396 return -ENOMEM;
1397
1398 fuse_copy_init(&cs, 1, NULL);
1399 cs.pipebufs = bufs;
1400 cs.pipe = pipe;
1401 ret = fuse_dev_do_read(fud, in, &cs, len);
1402 if (ret < 0)
1403 goto out;
1404
1405 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1406 ret = -EIO;
1407 goto out;
1408 }
1409
1410 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1411 /*
1412 * Need to be careful about this. Having buf->ops in module
1413 * code can Oops if the buffer persists after module unload.
1414 */
1415 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1416 bufs[page_nr].flags = 0;
1417 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1418 if (unlikely(ret < 0))
1419 break;
1420 }
1421 if (total)
1422 ret = total;
1423 out:
1424 for (; page_nr < cs.nr_segs; page_nr++)
1425 put_page(bufs[page_nr].page);
1426
1427 kfree(bufs);
1428 return ret;
1429 }
1430
1431 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1432 struct fuse_copy_state *cs)
1433 {
1434 struct fuse_notify_poll_wakeup_out outarg;
1435 int err = -EINVAL;
1436
1437 if (size != sizeof(outarg))
1438 goto err;
1439
1440 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1441 if (err)
1442 goto err;
1443
1444 fuse_copy_finish(cs);
1445 return fuse_notify_poll_wakeup(fc, &outarg);
1446
1447 err:
1448 fuse_copy_finish(cs);
1449 return err;
1450 }
1451
1452 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1453 struct fuse_copy_state *cs)
1454 {
1455 struct fuse_notify_inval_inode_out outarg;
1456 int err = -EINVAL;
1457
1458 if (size != sizeof(outarg))
1459 goto err;
1460
1461 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1462 if (err)
1463 goto err;
1464 fuse_copy_finish(cs);
1465
1466 down_read(&fc->killsb);
1467 err = -ENOENT;
1468 if (fc->sb) {
1469 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1470 outarg.off, outarg.len);
1471 }
1472 up_read(&fc->killsb);
1473 return err;
1474
1475 err:
1476 fuse_copy_finish(cs);
1477 return err;
1478 }
1479
1480 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1481 struct fuse_copy_state *cs)
1482 {
1483 struct fuse_notify_inval_entry_out outarg;
1484 int err = -ENOMEM;
1485 char *buf;
1486 struct qstr name;
1487
1488 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1489 if (!buf)
1490 goto err;
1491
1492 err = -EINVAL;
1493 if (size < sizeof(outarg))
1494 goto err;
1495
1496 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1497 if (err)
1498 goto err;
1499
1500 err = -ENAMETOOLONG;
1501 if (outarg.namelen > FUSE_NAME_MAX)
1502 goto err;
1503
1504 err = -EINVAL;
1505 if (size != sizeof(outarg) + outarg.namelen + 1)
1506 goto err;
1507
1508 name.name = buf;
1509 name.len = outarg.namelen;
1510 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1511 if (err)
1512 goto err;
1513 fuse_copy_finish(cs);
1514 buf[outarg.namelen] = 0;
1515
1516 down_read(&fc->killsb);
1517 err = -ENOENT;
1518 if (fc->sb)
1519 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1520 up_read(&fc->killsb);
1521 kfree(buf);
1522 return err;
1523
1524 err:
1525 kfree(buf);
1526 fuse_copy_finish(cs);
1527 return err;
1528 }
1529
1530 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1531 struct fuse_copy_state *cs)
1532 {
1533 struct fuse_notify_delete_out outarg;
1534 int err = -ENOMEM;
1535 char *buf;
1536 struct qstr name;
1537
1538 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1539 if (!buf)
1540 goto err;
1541
1542 err = -EINVAL;
1543 if (size < sizeof(outarg))
1544 goto err;
1545
1546 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1547 if (err)
1548 goto err;
1549
1550 err = -ENAMETOOLONG;
1551 if (outarg.namelen > FUSE_NAME_MAX)
1552 goto err;
1553
1554 err = -EINVAL;
1555 if (size != sizeof(outarg) + outarg.namelen + 1)
1556 goto err;
1557
1558 name.name = buf;
1559 name.len = outarg.namelen;
1560 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1561 if (err)
1562 goto err;
1563 fuse_copy_finish(cs);
1564 buf[outarg.namelen] = 0;
1565
1566 down_read(&fc->killsb);
1567 err = -ENOENT;
1568 if (fc->sb)
1569 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1570 outarg.child, &name);
1571 up_read(&fc->killsb);
1572 kfree(buf);
1573 return err;
1574
1575 err:
1576 kfree(buf);
1577 fuse_copy_finish(cs);
1578 return err;
1579 }
1580
1581 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1582 struct fuse_copy_state *cs)
1583 {
1584 struct fuse_notify_store_out outarg;
1585 struct inode *inode;
1586 struct address_space *mapping;
1587 u64 nodeid;
1588 int err;
1589 pgoff_t index;
1590 unsigned int offset;
1591 unsigned int num;
1592 loff_t file_size;
1593 loff_t end;
1594
1595 err = -EINVAL;
1596 if (size < sizeof(outarg))
1597 goto out_finish;
1598
1599 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1600 if (err)
1601 goto out_finish;
1602
1603 err = -EINVAL;
1604 if (size - sizeof(outarg) != outarg.size)
1605 goto out_finish;
1606
1607 nodeid = outarg.nodeid;
1608
1609 down_read(&fc->killsb);
1610
1611 err = -ENOENT;
1612 if (!fc->sb)
1613 goto out_up_killsb;
1614
1615 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1616 if (!inode)
1617 goto out_up_killsb;
1618
1619 mapping = inode->i_mapping;
1620 index = outarg.offset >> PAGE_SHIFT;
1621 offset = outarg.offset & ~PAGE_MASK;
1622 file_size = i_size_read(inode);
1623 end = outarg.offset + outarg.size;
1624 if (end > file_size) {
1625 file_size = end;
1626 fuse_write_update_size(inode, file_size);
1627 }
1628
1629 num = outarg.size;
1630 while (num) {
1631 struct page *page;
1632 unsigned int this_num;
1633
1634 err = -ENOMEM;
1635 page = find_or_create_page(mapping, index,
1636 mapping_gfp_mask(mapping));
1637 if (!page)
1638 goto out_iput;
1639
1640 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1641 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1642 if (!err && offset == 0 &&
1643 (this_num == PAGE_SIZE || file_size == end))
1644 SetPageUptodate(page);
1645 unlock_page(page);
1646 put_page(page);
1647
1648 if (err)
1649 goto out_iput;
1650
1651 num -= this_num;
1652 offset = 0;
1653 index++;
1654 }
1655
1656 err = 0;
1657
1658 out_iput:
1659 iput(inode);
1660 out_up_killsb:
1661 up_read(&fc->killsb);
1662 out_finish:
1663 fuse_copy_finish(cs);
1664 return err;
1665 }
1666
1667 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1668 {
1669 release_pages(req->pages, req->num_pages, false);
1670 }
1671
1672 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1673 struct fuse_notify_retrieve_out *outarg)
1674 {
1675 int err;
1676 struct address_space *mapping = inode->i_mapping;
1677 struct fuse_req *req;
1678 pgoff_t index;
1679 loff_t file_size;
1680 unsigned int num;
1681 unsigned int offset;
1682 size_t total_len = 0;
1683 int num_pages;
1684
1685 offset = outarg->offset & ~PAGE_MASK;
1686 file_size = i_size_read(inode);
1687
1688 num = min(outarg->size, fc->max_write);
1689 if (outarg->offset > file_size)
1690 num = 0;
1691 else if (outarg->offset + num > file_size)
1692 num = file_size - outarg->offset;
1693
1694 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1695 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1696
1697 req = fuse_get_req(fc, num_pages);
1698 if (IS_ERR(req))
1699 return PTR_ERR(req);
1700
1701 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1702 req->in.h.nodeid = outarg->nodeid;
1703 req->in.numargs = 2;
1704 req->in.argpages = 1;
1705 req->end = fuse_retrieve_end;
1706
1707 index = outarg->offset >> PAGE_SHIFT;
1708
1709 while (num && req->num_pages < num_pages) {
1710 struct page *page;
1711 unsigned int this_num;
1712
1713 page = find_get_page(mapping, index);
1714 if (!page)
1715 break;
1716
1717 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1718 req->pages[req->num_pages] = page;
1719 req->page_descs[req->num_pages].offset = offset;
1720 req->page_descs[req->num_pages].length = this_num;
1721 req->num_pages++;
1722
1723 offset = 0;
1724 num -= this_num;
1725 total_len += this_num;
1726 index++;
1727 }
1728 req->misc.retrieve_in.offset = outarg->offset;
1729 req->misc.retrieve_in.size = total_len;
1730 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1731 req->in.args[0].value = &req->misc.retrieve_in;
1732 req->in.args[1].size = total_len;
1733
1734 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1735 if (err) {
1736 fuse_retrieve_end(fc, req);
1737 fuse_put_request(fc, req);
1738 }
1739
1740 return err;
1741 }
1742
1743 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1744 struct fuse_copy_state *cs)
1745 {
1746 struct fuse_notify_retrieve_out outarg;
1747 struct inode *inode;
1748 int err;
1749
1750 err = -EINVAL;
1751 if (size != sizeof(outarg))
1752 goto copy_finish;
1753
1754 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1755 if (err)
1756 goto copy_finish;
1757
1758 fuse_copy_finish(cs);
1759
1760 down_read(&fc->killsb);
1761 err = -ENOENT;
1762 if (fc->sb) {
1763 u64 nodeid = outarg.nodeid;
1764
1765 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1766 if (inode) {
1767 err = fuse_retrieve(fc, inode, &outarg);
1768 iput(inode);
1769 }
1770 }
1771 up_read(&fc->killsb);
1772
1773 return err;
1774
1775 copy_finish:
1776 fuse_copy_finish(cs);
1777 return err;
1778 }
1779
1780 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1781 unsigned int size, struct fuse_copy_state *cs)
1782 {
1783 /* Don't try to move pages (yet) */
1784 cs->move_pages = 0;
1785
1786 switch (code) {
1787 case FUSE_NOTIFY_POLL:
1788 return fuse_notify_poll(fc, size, cs);
1789
1790 case FUSE_NOTIFY_INVAL_INODE:
1791 return fuse_notify_inval_inode(fc, size, cs);
1792
1793 case FUSE_NOTIFY_INVAL_ENTRY:
1794 return fuse_notify_inval_entry(fc, size, cs);
1795
1796 case FUSE_NOTIFY_STORE:
1797 return fuse_notify_store(fc, size, cs);
1798
1799 case FUSE_NOTIFY_RETRIEVE:
1800 return fuse_notify_retrieve(fc, size, cs);
1801
1802 case FUSE_NOTIFY_DELETE:
1803 return fuse_notify_delete(fc, size, cs);
1804
1805 default:
1806 fuse_copy_finish(cs);
1807 return -EINVAL;
1808 }
1809 }
1810
1811 /* Look up request on processing list by unique ID */
1812 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1813 {
1814 struct fuse_req *req;
1815
1816 list_for_each_entry(req, &fpq->processing, list) {
1817 if (req->in.h.unique == unique || req->intr_unique == unique)
1818 return req;
1819 }
1820 return NULL;
1821 }
1822
1823 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1824 unsigned nbytes)
1825 {
1826 unsigned reqsize = sizeof(struct fuse_out_header);
1827
1828 if (out->h.error)
1829 return nbytes != reqsize ? -EINVAL : 0;
1830
1831 reqsize += len_args(out->numargs, out->args);
1832
1833 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1834 return -EINVAL;
1835 else if (reqsize > nbytes) {
1836 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1837 unsigned diffsize = reqsize - nbytes;
1838 if (diffsize > lastarg->size)
1839 return -EINVAL;
1840 lastarg->size -= diffsize;
1841 }
1842 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1843 out->page_zeroing);
1844 }
1845
1846 /*
1847 * Write a single reply to a request. First the header is copied from
1848 * the write buffer. The request is then searched on the processing
1849 * list by the unique ID found in the header. If found, then remove
1850 * it from the list and copy the rest of the buffer to the request.
1851 * The request is finished by calling request_end()
1852 */
1853 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1854 struct fuse_copy_state *cs, size_t nbytes)
1855 {
1856 int err;
1857 struct fuse_conn *fc = fud->fc;
1858 struct fuse_pqueue *fpq = &fud->pq;
1859 struct fuse_req *req;
1860 struct fuse_out_header oh;
1861
1862 if (nbytes < sizeof(struct fuse_out_header))
1863 return -EINVAL;
1864
1865 err = fuse_copy_one(cs, &oh, sizeof(oh));
1866 if (err)
1867 goto err_finish;
1868
1869 err = -EINVAL;
1870 if (oh.len != nbytes)
1871 goto err_finish;
1872
1873 /*
1874 * Zero oh.unique indicates unsolicited notification message
1875 * and error contains notification code.
1876 */
1877 if (!oh.unique) {
1878 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1879 return err ? err : nbytes;
1880 }
1881
1882 err = -EINVAL;
1883 if (oh.error <= -1000 || oh.error > 0)
1884 goto err_finish;
1885
1886 spin_lock(&fpq->lock);
1887 err = -ENOENT;
1888 if (!fpq->connected)
1889 goto err_unlock_pq;
1890
1891 req = request_find(fpq, oh.unique);
1892 if (!req)
1893 goto err_unlock_pq;
1894
1895 /* Is it an interrupt reply? */
1896 if (req->intr_unique == oh.unique) {
1897 __fuse_get_request(req);
1898 spin_unlock(&fpq->lock);
1899
1900 err = -EINVAL;
1901 if (nbytes != sizeof(struct fuse_out_header)) {
1902 fuse_put_request(fc, req);
1903 goto err_finish;
1904 }
1905
1906 if (oh.error == -ENOSYS)
1907 fc->no_interrupt = 1;
1908 else if (oh.error == -EAGAIN)
1909 queue_interrupt(&fc->iq, req);
1910 fuse_put_request(fc, req);
1911
1912 fuse_copy_finish(cs);
1913 return nbytes;
1914 }
1915
1916 clear_bit(FR_SENT, &req->flags);
1917 list_move(&req->list, &fpq->io);
1918 req->out.h = oh;
1919 set_bit(FR_LOCKED, &req->flags);
1920 spin_unlock(&fpq->lock);
1921 cs->req = req;
1922 if (!req->out.page_replace)
1923 cs->move_pages = 0;
1924
1925 err = copy_out_args(cs, &req->out, nbytes);
1926 fuse_copy_finish(cs);
1927
1928 spin_lock(&fpq->lock);
1929 clear_bit(FR_LOCKED, &req->flags);
1930 if (!fpq->connected)
1931 err = -ENOENT;
1932 else if (err)
1933 req->out.h.error = -EIO;
1934 if (!test_bit(FR_PRIVATE, &req->flags))
1935 list_del_init(&req->list);
1936 spin_unlock(&fpq->lock);
1937
1938 request_end(fc, req);
1939
1940 return err ? err : nbytes;
1941
1942 err_unlock_pq:
1943 spin_unlock(&fpq->lock);
1944 err_finish:
1945 fuse_copy_finish(cs);
1946 return err;
1947 }
1948
1949 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1950 {
1951 struct fuse_copy_state cs;
1952 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1953
1954 if (!fud)
1955 return -EPERM;
1956
1957 if (!iter_is_iovec(from))
1958 return -EINVAL;
1959
1960 fuse_copy_init(&cs, 0, from);
1961
1962 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1963 }
1964
1965 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1966 struct file *out, loff_t *ppos,
1967 size_t len, unsigned int flags)
1968 {
1969 unsigned nbuf;
1970 unsigned idx;
1971 struct pipe_buffer *bufs;
1972 struct fuse_copy_state cs;
1973 struct fuse_dev *fud;
1974 size_t rem;
1975 ssize_t ret;
1976
1977 fud = fuse_get_dev(out);
1978 if (!fud)
1979 return -EPERM;
1980
1981 pipe_lock(pipe);
1982
1983 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1984 if (!bufs) {
1985 pipe_unlock(pipe);
1986 return -ENOMEM;
1987 }
1988
1989 nbuf = 0;
1990 rem = 0;
1991 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1992 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1993
1994 ret = -EINVAL;
1995 if (rem < len)
1996 goto out_free;
1997
1998 rem = len;
1999 while (rem) {
2000 struct pipe_buffer *ibuf;
2001 struct pipe_buffer *obuf;
2002
2003 BUG_ON(nbuf >= pipe->buffers);
2004 BUG_ON(!pipe->nrbufs);
2005 ibuf = &pipe->bufs[pipe->curbuf];
2006 obuf = &bufs[nbuf];
2007
2008 if (rem >= ibuf->len) {
2009 *obuf = *ibuf;
2010 ibuf->ops = NULL;
2011 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2012 pipe->nrbufs--;
2013 } else {
2014 if (!pipe_buf_get(pipe, ibuf))
2015 goto out_free;
2016
2017 *obuf = *ibuf;
2018 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2019 obuf->len = rem;
2020 ibuf->offset += obuf->len;
2021 ibuf->len -= obuf->len;
2022 }
2023 nbuf++;
2024 rem -= obuf->len;
2025 }
2026 pipe_unlock(pipe);
2027
2028 fuse_copy_init(&cs, 0, NULL);
2029 cs.pipebufs = bufs;
2030 cs.nr_segs = nbuf;
2031 cs.pipe = pipe;
2032
2033 if (flags & SPLICE_F_MOVE)
2034 cs.move_pages = 1;
2035
2036 ret = fuse_dev_do_write(fud, &cs, len);
2037
2038 pipe_lock(pipe);
2039 out_free:
2040 for (idx = 0; idx < nbuf; idx++)
2041 pipe_buf_release(pipe, &bufs[idx]);
2042 pipe_unlock(pipe);
2043
2044 kfree(bufs);
2045 return ret;
2046 }
2047
2048 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2049 {
2050 unsigned mask = POLLOUT | POLLWRNORM;
2051 struct fuse_iqueue *fiq;
2052 struct fuse_dev *fud = fuse_get_dev(file);
2053
2054 if (!fud)
2055 return POLLERR;
2056
2057 fiq = &fud->fc->iq;
2058 poll_wait(file, &fiq->waitq, wait);
2059
2060 spin_lock(&fiq->waitq.lock);
2061 if (!fiq->connected)
2062 mask = POLLERR;
2063 else if (request_pending(fiq))
2064 mask |= POLLIN | POLLRDNORM;
2065 spin_unlock(&fiq->waitq.lock);
2066
2067 return mask;
2068 }
2069
2070 /*
2071 * Abort all requests on the given list (pending or processing)
2072 *
2073 * This function releases and reacquires fc->lock
2074 */
2075 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2076 {
2077 while (!list_empty(head)) {
2078 struct fuse_req *req;
2079 req = list_entry(head->next, struct fuse_req, list);
2080 req->out.h.error = -ECONNABORTED;
2081 clear_bit(FR_SENT, &req->flags);
2082 list_del_init(&req->list);
2083 request_end(fc, req);
2084 }
2085 }
2086
2087 static void end_polls(struct fuse_conn *fc)
2088 {
2089 struct rb_node *p;
2090
2091 p = rb_first(&fc->polled_files);
2092
2093 while (p) {
2094 struct fuse_file *ff;
2095 ff = rb_entry(p, struct fuse_file, polled_node);
2096 wake_up_interruptible_all(&ff->poll_wait);
2097
2098 p = rb_next(p);
2099 }
2100 }
2101
2102 /*
2103 * Abort all requests.
2104 *
2105 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2106 * filesystem.
2107 *
2108 * The same effect is usually achievable through killing the filesystem daemon
2109 * and all users of the filesystem. The exception is the combination of an
2110 * asynchronous request and the tricky deadlock (see
2111 * Documentation/filesystems/fuse.txt).
2112 *
2113 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2114 * requests, they should be finished off immediately. Locked requests will be
2115 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2116 * requests. It is possible that some request will finish before we can. This
2117 * is OK, the request will in that case be removed from the list before we touch
2118 * it.
2119 */
2120 void fuse_abort_conn(struct fuse_conn *fc)
2121 {
2122 struct fuse_iqueue *fiq = &fc->iq;
2123
2124 spin_lock(&fc->lock);
2125 if (fc->connected) {
2126 struct fuse_dev *fud;
2127 struct fuse_req *req, *next;
2128 LIST_HEAD(to_end1);
2129 LIST_HEAD(to_end2);
2130
2131 fc->connected = 0;
2132 fc->blocked = 0;
2133 fuse_set_initialized(fc);
2134 list_for_each_entry(fud, &fc->devices, entry) {
2135 struct fuse_pqueue *fpq = &fud->pq;
2136
2137 spin_lock(&fpq->lock);
2138 fpq->connected = 0;
2139 list_for_each_entry_safe(req, next, &fpq->io, list) {
2140 req->out.h.error = -ECONNABORTED;
2141 spin_lock(&req->waitq.lock);
2142 set_bit(FR_ABORTED, &req->flags);
2143 if (!test_bit(FR_LOCKED, &req->flags)) {
2144 set_bit(FR_PRIVATE, &req->flags);
2145 __fuse_get_request(req);
2146 list_move(&req->list, &to_end1);
2147 }
2148 spin_unlock(&req->waitq.lock);
2149 }
2150 list_splice_init(&fpq->processing, &to_end2);
2151 spin_unlock(&fpq->lock);
2152 }
2153 fc->max_background = UINT_MAX;
2154 flush_bg_queue(fc);
2155
2156 spin_lock(&fiq->waitq.lock);
2157 fiq->connected = 0;
2158 list_splice_init(&fiq->pending, &to_end2);
2159 list_for_each_entry(req, &to_end2, list)
2160 clear_bit(FR_PENDING, &req->flags);
2161 while (forget_pending(fiq))
2162 kfree(dequeue_forget(fiq, 1, NULL));
2163 wake_up_all_locked(&fiq->waitq);
2164 spin_unlock(&fiq->waitq.lock);
2165 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2166 end_polls(fc);
2167 wake_up_all(&fc->blocked_waitq);
2168 spin_unlock(&fc->lock);
2169
2170 while (!list_empty(&to_end1)) {
2171 req = list_first_entry(&to_end1, struct fuse_req, list);
2172 list_del_init(&req->list);
2173 request_end(fc, req);
2174 }
2175 end_requests(fc, &to_end2);
2176 } else {
2177 spin_unlock(&fc->lock);
2178 }
2179 }
2180 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2181
2182 void fuse_wait_aborted(struct fuse_conn *fc)
2183 {
2184 /* matches implicit memory barrier in fuse_drop_waiting() */
2185 smp_mb();
2186 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2187 }
2188
2189 int fuse_dev_release(struct inode *inode, struct file *file)
2190 {
2191 struct fuse_dev *fud = fuse_get_dev(file);
2192
2193 if (fud) {
2194 struct fuse_conn *fc = fud->fc;
2195 struct fuse_pqueue *fpq = &fud->pq;
2196 LIST_HEAD(to_end);
2197
2198 spin_lock(&fpq->lock);
2199 WARN_ON(!list_empty(&fpq->io));
2200 list_splice_init(&fpq->processing, &to_end);
2201 spin_unlock(&fpq->lock);
2202
2203 end_requests(fc, &to_end);
2204
2205 /* Are we the last open device? */
2206 if (atomic_dec_and_test(&fc->dev_count)) {
2207 WARN_ON(fc->iq.fasync != NULL);
2208 fuse_abort_conn(fc);
2209 }
2210 fuse_dev_free(fud);
2211 }
2212 return 0;
2213 }
2214 EXPORT_SYMBOL_GPL(fuse_dev_release);
2215
2216 static int fuse_dev_fasync(int fd, struct file *file, int on)
2217 {
2218 struct fuse_dev *fud = fuse_get_dev(file);
2219
2220 if (!fud)
2221 return -EPERM;
2222
2223 /* No locking - fasync_helper does its own locking */
2224 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2225 }
2226
2227 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2228 {
2229 struct fuse_dev *fud;
2230
2231 if (new->private_data)
2232 return -EINVAL;
2233
2234 fud = fuse_dev_alloc(fc);
2235 if (!fud)
2236 return -ENOMEM;
2237
2238 new->private_data = fud;
2239 atomic_inc(&fc->dev_count);
2240
2241 return 0;
2242 }
2243
2244 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2245 unsigned long arg)
2246 {
2247 int err = -ENOTTY;
2248
2249 if (cmd == FUSE_DEV_IOC_CLONE) {
2250 int oldfd;
2251
2252 err = -EFAULT;
2253 if (!get_user(oldfd, (__u32 __user *) arg)) {
2254 struct file *old = fget(oldfd);
2255
2256 err = -EINVAL;
2257 if (old) {
2258 struct fuse_dev *fud = NULL;
2259
2260 /*
2261 * Check against file->f_op because CUSE
2262 * uses the same ioctl handler.
2263 */
2264 if (old->f_op == file->f_op &&
2265 old->f_cred->user_ns == file->f_cred->user_ns)
2266 fud = fuse_get_dev(old);
2267
2268 if (fud) {
2269 mutex_lock(&fuse_mutex);
2270 err = fuse_device_clone(fud->fc, file);
2271 mutex_unlock(&fuse_mutex);
2272 }
2273 fput(old);
2274 }
2275 }
2276 }
2277 return err;
2278 }
2279
2280 const struct file_operations fuse_dev_operations = {
2281 .owner = THIS_MODULE,
2282 .open = fuse_dev_open,
2283 .llseek = no_llseek,
2284 .read_iter = fuse_dev_read,
2285 .splice_read = fuse_dev_splice_read,
2286 .write_iter = fuse_dev_write,
2287 .splice_write = fuse_dev_splice_write,
2288 .poll = fuse_dev_poll,
2289 .release = fuse_dev_release,
2290 .fasync = fuse_dev_fasync,
2291 .unlocked_ioctl = fuse_dev_ioctl,
2292 .compat_ioctl = fuse_dev_ioctl,
2293 };
2294 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2295
2296 static struct miscdevice fuse_miscdevice = {
2297 .minor = FUSE_MINOR,
2298 .name = "fuse",
2299 .fops = &fuse_dev_operations,
2300 };
2301
2302 int __init fuse_dev_init(void)
2303 {
2304 int err = -ENOMEM;
2305 fuse_req_cachep = kmem_cache_create("fuse_request",
2306 sizeof(struct fuse_req),
2307 0, 0, NULL);
2308 if (!fuse_req_cachep)
2309 goto out;
2310
2311 err = misc_register(&fuse_miscdevice);
2312 if (err)
2313 goto out_cache_clean;
2314
2315 return 0;
2316
2317 out_cache_clean:
2318 kmem_cache_destroy(fuse_req_cachep);
2319 out:
2320 return err;
2321 }
2322
2323 void fuse_dev_cleanup(void)
2324 {
2325 misc_deregister(&fuse_miscdevice);
2326 kmem_cache_destroy(fuse_req_cachep);
2327 }
Linux with added FPC-III support