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