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fuse: move list_del_init() from request_end() into callers
[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 * Called with fc->lock, unlocks it
381 */
382 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
383 __releases(fc->lock)
384 {
385 struct fuse_iqueue *fiq = &fc->iq;
386 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
387 req->end = NULL;
388 spin_lock(&fiq->waitq.lock);
389 list_del_init(&req->intr_entry);
390 spin_unlock(&fiq->waitq.lock);
391 WARN_ON(test_bit(FR_PENDING, &req->flags));
392 WARN_ON(test_bit(FR_SENT, &req->flags));
393 smp_wmb();
394 set_bit(FR_FINISHED, &req->flags);
395 if (test_bit(FR_BACKGROUND, &req->flags)) {
396 clear_bit(FR_BACKGROUND, &req->flags);
397 if (fc->num_background == fc->max_background)
398 fc->blocked = 0;
399
400 /* Wake up next waiter, if any */
401 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
402 wake_up(&fc->blocked_waitq);
403
404 if (fc->num_background == fc->congestion_threshold &&
405 fc->connected && fc->bdi_initialized) {
406 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
407 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
408 }
409 fc->num_background--;
410 fc->active_background--;
411 flush_bg_queue(fc);
412 }
413 spin_unlock(&fc->lock);
414 wake_up(&req->waitq);
415 if (end)
416 end(fc, req);
417 fuse_put_request(fc, req);
418 }
419
420 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
421 {
422 spin_lock(&fiq->waitq.lock);
423 if (list_empty(&req->intr_entry)) {
424 list_add_tail(&req->intr_entry, &fiq->interrupts);
425 wake_up_locked(&fiq->waitq);
426 }
427 spin_unlock(&fiq->waitq.lock);
428 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
429 }
430
431 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
432 {
433 struct fuse_iqueue *fiq = &fc->iq;
434 int err;
435
436 if (!fc->no_interrupt) {
437 /* Any signal may interrupt this */
438 err = wait_event_interruptible(req->waitq,
439 test_bit(FR_FINISHED, &req->flags));
440 if (!err)
441 return;
442
443 set_bit(FR_INTERRUPTED, &req->flags);
444 /* matches barrier in fuse_dev_do_read() */
445 smp_mb__after_atomic();
446 if (test_bit(FR_SENT, &req->flags))
447 queue_interrupt(fiq, req);
448 }
449
450 if (!test_bit(FR_FORCE, &req->flags)) {
451 sigset_t oldset;
452
453 /* Only fatal signals may interrupt this */
454 block_sigs(&oldset);
455 err = wait_event_interruptible(req->waitq,
456 test_bit(FR_FINISHED, &req->flags));
457 restore_sigs(&oldset);
458
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 &&
598 fc->bdi_initialized) {
599 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
600 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
601 }
602 list_add_tail(&req->list, &fc->bg_queue);
603 flush_bg_queue(fc);
604 }
605
606 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
607 {
608 BUG_ON(!req->end);
609 spin_lock(&fc->lock);
610 if (fc->connected) {
611 fuse_request_send_background_locked(fc, req);
612 spin_unlock(&fc->lock);
613 } else {
614 spin_unlock(&fc->lock);
615 req->out.h.error = -ENOTCONN;
616 req->end(fc, req);
617 fuse_put_request(fc, req);
618 }
619 }
620 EXPORT_SYMBOL_GPL(fuse_request_send_background);
621
622 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
623 struct fuse_req *req, u64 unique)
624 {
625 int err = -ENODEV;
626 struct fuse_iqueue *fiq = &fc->iq;
627
628 __clear_bit(FR_ISREPLY, &req->flags);
629 req->in.h.unique = unique;
630 spin_lock(&fiq->waitq.lock);
631 if (fiq->connected) {
632 queue_request(fiq, req);
633 err = 0;
634 }
635 spin_unlock(&fiq->waitq.lock);
636
637 return err;
638 }
639
640 void fuse_force_forget(struct file *file, u64 nodeid)
641 {
642 struct inode *inode = file_inode(file);
643 struct fuse_conn *fc = get_fuse_conn(inode);
644 struct fuse_req *req;
645 struct fuse_forget_in inarg;
646
647 memset(&inarg, 0, sizeof(inarg));
648 inarg.nlookup = 1;
649 req = fuse_get_req_nofail_nopages(fc, file);
650 req->in.h.opcode = FUSE_FORGET;
651 req->in.h.nodeid = nodeid;
652 req->in.numargs = 1;
653 req->in.args[0].size = sizeof(inarg);
654 req->in.args[0].value = &inarg;
655 __clear_bit(FR_ISREPLY, &req->flags);
656 __fuse_request_send(fc, req);
657 /* ignore errors */
658 fuse_put_request(fc, req);
659 }
660
661 /*
662 * Lock the request. Up to the next unlock_request() there mustn't be
663 * anything that could cause a page-fault. If the request was already
664 * aborted bail out.
665 */
666 static int lock_request(struct fuse_req *req)
667 {
668 int err = 0;
669 if (req) {
670 spin_lock(&req->waitq.lock);
671 if (test_bit(FR_ABORTED, &req->flags))
672 err = -ENOENT;
673 else
674 set_bit(FR_LOCKED, &req->flags);
675 spin_unlock(&req->waitq.lock);
676 }
677 return err;
678 }
679
680 /*
681 * Unlock request. If it was aborted while locked, caller is responsible
682 * for unlocking and ending the request.
683 */
684 static int unlock_request(struct fuse_req *req)
685 {
686 int err = 0;
687 if (req) {
688 spin_lock(&req->waitq.lock);
689 if (test_bit(FR_ABORTED, &req->flags))
690 err = -ENOENT;
691 else
692 clear_bit(FR_LOCKED, &req->flags);
693 spin_unlock(&req->waitq.lock);
694 }
695 return err;
696 }
697
698 struct fuse_copy_state {
699 int write;
700 struct fuse_req *req;
701 struct iov_iter *iter;
702 struct pipe_buffer *pipebufs;
703 struct pipe_buffer *currbuf;
704 struct pipe_inode_info *pipe;
705 unsigned long nr_segs;
706 struct page *pg;
707 unsigned len;
708 unsigned offset;
709 unsigned move_pages:1;
710 };
711
712 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
713 struct iov_iter *iter)
714 {
715 memset(cs, 0, sizeof(*cs));
716 cs->write = write;
717 cs->iter = iter;
718 }
719
720 /* Unmap and put previous page of userspace buffer */
721 static void fuse_copy_finish(struct fuse_copy_state *cs)
722 {
723 if (cs->currbuf) {
724 struct pipe_buffer *buf = cs->currbuf;
725
726 if (cs->write)
727 buf->len = PAGE_SIZE - cs->len;
728 cs->currbuf = NULL;
729 } else if (cs->pg) {
730 if (cs->write) {
731 flush_dcache_page(cs->pg);
732 set_page_dirty_lock(cs->pg);
733 }
734 put_page(cs->pg);
735 }
736 cs->pg = NULL;
737 }
738
739 /*
740 * Get another pagefull of userspace buffer, and map it to kernel
741 * address space, and lock request
742 */
743 static int fuse_copy_fill(struct fuse_copy_state *cs)
744 {
745 struct page *page;
746 int err;
747
748 err = unlock_request(cs->req);
749 if (err)
750 return err;
751
752 fuse_copy_finish(cs);
753 if (cs->pipebufs) {
754 struct pipe_buffer *buf = cs->pipebufs;
755
756 if (!cs->write) {
757 err = buf->ops->confirm(cs->pipe, buf);
758 if (err)
759 return err;
760
761 BUG_ON(!cs->nr_segs);
762 cs->currbuf = buf;
763 cs->pg = buf->page;
764 cs->offset = buf->offset;
765 cs->len = buf->len;
766 cs->pipebufs++;
767 cs->nr_segs--;
768 } else {
769 if (cs->nr_segs == cs->pipe->buffers)
770 return -EIO;
771
772 page = alloc_page(GFP_HIGHUSER);
773 if (!page)
774 return -ENOMEM;
775
776 buf->page = page;
777 buf->offset = 0;
778 buf->len = 0;
779
780 cs->currbuf = buf;
781 cs->pg = page;
782 cs->offset = 0;
783 cs->len = PAGE_SIZE;
784 cs->pipebufs++;
785 cs->nr_segs++;
786 }
787 } else {
788 size_t off;
789 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
790 if (err < 0)
791 return err;
792 BUG_ON(!err);
793 cs->len = err;
794 cs->offset = off;
795 cs->pg = page;
796 cs->offset = off;
797 iov_iter_advance(cs->iter, err);
798 }
799
800 return lock_request(cs->req);
801 }
802
803 /* Do as much copy to/from userspace buffer as we can */
804 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
805 {
806 unsigned ncpy = min(*size, cs->len);
807 if (val) {
808 void *pgaddr = kmap_atomic(cs->pg);
809 void *buf = pgaddr + cs->offset;
810
811 if (cs->write)
812 memcpy(buf, *val, ncpy);
813 else
814 memcpy(*val, buf, ncpy);
815
816 kunmap_atomic(pgaddr);
817 *val += ncpy;
818 }
819 *size -= ncpy;
820 cs->len -= ncpy;
821 cs->offset += ncpy;
822 return ncpy;
823 }
824
825 static int fuse_check_page(struct page *page)
826 {
827 if (page_mapcount(page) ||
828 page->mapping != NULL ||
829 page_count(page) != 1 ||
830 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
831 ~(1 << PG_locked |
832 1 << PG_referenced |
833 1 << PG_uptodate |
834 1 << PG_lru |
835 1 << PG_active |
836 1 << PG_reclaim))) {
837 printk(KERN_WARNING "fuse: trying to steal weird page\n");
838 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);
839 return 1;
840 }
841 return 0;
842 }
843
844 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
845 {
846 int err;
847 struct page *oldpage = *pagep;
848 struct page *newpage;
849 struct pipe_buffer *buf = cs->pipebufs;
850
851 err = unlock_request(cs->req);
852 if (err)
853 return err;
854
855 fuse_copy_finish(cs);
856
857 err = buf->ops->confirm(cs->pipe, buf);
858 if (err)
859 return err;
860
861 BUG_ON(!cs->nr_segs);
862 cs->currbuf = buf;
863 cs->len = buf->len;
864 cs->pipebufs++;
865 cs->nr_segs--;
866
867 if (cs->len != PAGE_SIZE)
868 goto out_fallback;
869
870 if (buf->ops->steal(cs->pipe, buf) != 0)
871 goto out_fallback;
872
873 newpage = buf->page;
874
875 if (!PageUptodate(newpage))
876 SetPageUptodate(newpage);
877
878 ClearPageMappedToDisk(newpage);
879
880 if (fuse_check_page(newpage) != 0)
881 goto out_fallback_unlock;
882
883 /*
884 * This is a new and locked page, it shouldn't be mapped or
885 * have any special flags on it
886 */
887 if (WARN_ON(page_mapped(oldpage)))
888 goto out_fallback_unlock;
889 if (WARN_ON(page_has_private(oldpage)))
890 goto out_fallback_unlock;
891 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
892 goto out_fallback_unlock;
893 if (WARN_ON(PageMlocked(oldpage)))
894 goto out_fallback_unlock;
895
896 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
897 if (err) {
898 unlock_page(newpage);
899 return err;
900 }
901
902 page_cache_get(newpage);
903
904 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
905 lru_cache_add_file(newpage);
906
907 err = 0;
908 spin_lock(&cs->req->waitq.lock);
909 if (test_bit(FR_ABORTED, &cs->req->flags))
910 err = -ENOENT;
911 else
912 *pagep = newpage;
913 spin_unlock(&cs->req->waitq.lock);
914
915 if (err) {
916 unlock_page(newpage);
917 page_cache_release(newpage);
918 return err;
919 }
920
921 unlock_page(oldpage);
922 page_cache_release(oldpage);
923 cs->len = 0;
924
925 return 0;
926
927 out_fallback_unlock:
928 unlock_page(newpage);
929 out_fallback:
930 cs->pg = buf->page;
931 cs->offset = buf->offset;
932
933 err = lock_request(cs->req);
934 if (err)
935 return err;
936
937 return 1;
938 }
939
940 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
941 unsigned offset, unsigned count)
942 {
943 struct pipe_buffer *buf;
944 int err;
945
946 if (cs->nr_segs == cs->pipe->buffers)
947 return -EIO;
948
949 err = unlock_request(cs->req);
950 if (err)
951 return err;
952
953 fuse_copy_finish(cs);
954
955 buf = cs->pipebufs;
956 page_cache_get(page);
957 buf->page = page;
958 buf->offset = offset;
959 buf->len = count;
960
961 cs->pipebufs++;
962 cs->nr_segs++;
963 cs->len = 0;
964
965 return 0;
966 }
967
968 /*
969 * Copy a page in the request to/from the userspace buffer. Must be
970 * done atomically
971 */
972 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
973 unsigned offset, unsigned count, int zeroing)
974 {
975 int err;
976 struct page *page = *pagep;
977
978 if (page && zeroing && count < PAGE_SIZE)
979 clear_highpage(page);
980
981 while (count) {
982 if (cs->write && cs->pipebufs && page) {
983 return fuse_ref_page(cs, page, offset, count);
984 } else if (!cs->len) {
985 if (cs->move_pages && page &&
986 offset == 0 && count == PAGE_SIZE) {
987 err = fuse_try_move_page(cs, pagep);
988 if (err <= 0)
989 return err;
990 } else {
991 err = fuse_copy_fill(cs);
992 if (err)
993 return err;
994 }
995 }
996 if (page) {
997 void *mapaddr = kmap_atomic(page);
998 void *buf = mapaddr + offset;
999 offset += fuse_copy_do(cs, &buf, &count);
1000 kunmap_atomic(mapaddr);
1001 } else
1002 offset += fuse_copy_do(cs, NULL, &count);
1003 }
1004 if (page && !cs->write)
1005 flush_dcache_page(page);
1006 return 0;
1007 }
1008
1009 /* Copy pages in the request to/from userspace buffer */
1010 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1011 int zeroing)
1012 {
1013 unsigned i;
1014 struct fuse_req *req = cs->req;
1015
1016 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1017 int err;
1018 unsigned offset = req->page_descs[i].offset;
1019 unsigned count = min(nbytes, req->page_descs[i].length);
1020
1021 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1022 zeroing);
1023 if (err)
1024 return err;
1025
1026 nbytes -= count;
1027 }
1028 return 0;
1029 }
1030
1031 /* Copy a single argument in the request to/from userspace buffer */
1032 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1033 {
1034 while (size) {
1035 if (!cs->len) {
1036 int err = fuse_copy_fill(cs);
1037 if (err)
1038 return err;
1039 }
1040 fuse_copy_do(cs, &val, &size);
1041 }
1042 return 0;
1043 }
1044
1045 /* Copy request arguments to/from userspace buffer */
1046 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1047 unsigned argpages, struct fuse_arg *args,
1048 int zeroing)
1049 {
1050 int err = 0;
1051 unsigned i;
1052
1053 for (i = 0; !err && i < numargs; i++) {
1054 struct fuse_arg *arg = &args[i];
1055 if (i == numargs - 1 && argpages)
1056 err = fuse_copy_pages(cs, arg->size, zeroing);
1057 else
1058 err = fuse_copy_one(cs, arg->value, arg->size);
1059 }
1060 return err;
1061 }
1062
1063 static int forget_pending(struct fuse_iqueue *fiq)
1064 {
1065 return fiq->forget_list_head.next != NULL;
1066 }
1067
1068 static int request_pending(struct fuse_iqueue *fiq)
1069 {
1070 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1071 forget_pending(fiq);
1072 }
1073
1074 /*
1075 * Transfer an interrupt request to userspace
1076 *
1077 * Unlike other requests this is assembled on demand, without a need
1078 * to allocate a separate fuse_req structure.
1079 *
1080 * Called with fiq->waitq.lock held, releases it
1081 */
1082 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1083 struct fuse_copy_state *cs,
1084 size_t nbytes, struct fuse_req *req)
1085 __releases(fiq->waitq.lock)
1086 {
1087 struct fuse_in_header ih;
1088 struct fuse_interrupt_in arg;
1089 unsigned reqsize = sizeof(ih) + sizeof(arg);
1090 int err;
1091
1092 list_del_init(&req->intr_entry);
1093 req->intr_unique = fuse_get_unique(fiq);
1094 memset(&ih, 0, sizeof(ih));
1095 memset(&arg, 0, sizeof(arg));
1096 ih.len = reqsize;
1097 ih.opcode = FUSE_INTERRUPT;
1098 ih.unique = req->intr_unique;
1099 arg.unique = req->in.h.unique;
1100
1101 spin_unlock(&fiq->waitq.lock);
1102 if (nbytes < reqsize)
1103 return -EINVAL;
1104
1105 err = fuse_copy_one(cs, &ih, sizeof(ih));
1106 if (!err)
1107 err = fuse_copy_one(cs, &arg, sizeof(arg));
1108 fuse_copy_finish(cs);
1109
1110 return err ? err : reqsize;
1111 }
1112
1113 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1114 unsigned max,
1115 unsigned *countp)
1116 {
1117 struct fuse_forget_link *head = fiq->forget_list_head.next;
1118 struct fuse_forget_link **newhead = &head;
1119 unsigned count;
1120
1121 for (count = 0; *newhead != NULL && count < max; count++)
1122 newhead = &(*newhead)->next;
1123
1124 fiq->forget_list_head.next = *newhead;
1125 *newhead = NULL;
1126 if (fiq->forget_list_head.next == NULL)
1127 fiq->forget_list_tail = &fiq->forget_list_head;
1128
1129 if (countp != NULL)
1130 *countp = count;
1131
1132 return head;
1133 }
1134
1135 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1136 struct fuse_copy_state *cs,
1137 size_t nbytes)
1138 __releases(fiq->waitq.lock)
1139 {
1140 int err;
1141 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1142 struct fuse_forget_in arg = {
1143 .nlookup = forget->forget_one.nlookup,
1144 };
1145 struct fuse_in_header ih = {
1146 .opcode = FUSE_FORGET,
1147 .nodeid = forget->forget_one.nodeid,
1148 .unique = fuse_get_unique(fiq),
1149 .len = sizeof(ih) + sizeof(arg),
1150 };
1151
1152 spin_unlock(&fiq->waitq.lock);
1153 kfree(forget);
1154 if (nbytes < ih.len)
1155 return -EINVAL;
1156
1157 err = fuse_copy_one(cs, &ih, sizeof(ih));
1158 if (!err)
1159 err = fuse_copy_one(cs, &arg, sizeof(arg));
1160 fuse_copy_finish(cs);
1161
1162 if (err)
1163 return err;
1164
1165 return ih.len;
1166 }
1167
1168 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1169 struct fuse_copy_state *cs, size_t nbytes)
1170 __releases(fiq->waitq.lock)
1171 {
1172 int err;
1173 unsigned max_forgets;
1174 unsigned count;
1175 struct fuse_forget_link *head;
1176 struct fuse_batch_forget_in arg = { .count = 0 };
1177 struct fuse_in_header ih = {
1178 .opcode = FUSE_BATCH_FORGET,
1179 .unique = fuse_get_unique(fiq),
1180 .len = sizeof(ih) + sizeof(arg),
1181 };
1182
1183 if (nbytes < ih.len) {
1184 spin_unlock(&fiq->waitq.lock);
1185 return -EINVAL;
1186 }
1187
1188 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1189 head = dequeue_forget(fiq, max_forgets, &count);
1190 spin_unlock(&fiq->waitq.lock);
1191
1192 arg.count = count;
1193 ih.len += count * sizeof(struct fuse_forget_one);
1194 err = fuse_copy_one(cs, &ih, sizeof(ih));
1195 if (!err)
1196 err = fuse_copy_one(cs, &arg, sizeof(arg));
1197
1198 while (head) {
1199 struct fuse_forget_link *forget = head;
1200
1201 if (!err) {
1202 err = fuse_copy_one(cs, &forget->forget_one,
1203 sizeof(forget->forget_one));
1204 }
1205 head = forget->next;
1206 kfree(forget);
1207 }
1208
1209 fuse_copy_finish(cs);
1210
1211 if (err)
1212 return err;
1213
1214 return ih.len;
1215 }
1216
1217 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1218 struct fuse_copy_state *cs,
1219 size_t nbytes)
1220 __releases(fiq->waitq.lock)
1221 {
1222 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1223 return fuse_read_single_forget(fiq, cs, nbytes);
1224 else
1225 return fuse_read_batch_forget(fiq, cs, nbytes);
1226 }
1227
1228 /*
1229 * Read a single request into the userspace filesystem's buffer. This
1230 * function waits until a request is available, then removes it from
1231 * the pending list and copies request data to userspace buffer. If
1232 * no reply is needed (FORGET) or request has been aborted or there
1233 * was an error during the copying then it's finished by calling
1234 * request_end(). Otherwise add it to the processing list, and set
1235 * the 'sent' flag.
1236 */
1237 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1238 struct fuse_copy_state *cs, size_t nbytes)
1239 {
1240 int err;
1241 struct fuse_iqueue *fiq = &fc->iq;
1242 struct fuse_pqueue *fpq = &fc->pq;
1243 struct fuse_req *req;
1244 struct fuse_in *in;
1245 unsigned reqsize;
1246
1247 restart:
1248 spin_lock(&fiq->waitq.lock);
1249 err = -EAGAIN;
1250 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1251 !request_pending(fiq))
1252 goto err_unlock;
1253
1254 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1255 !fiq->connected || request_pending(fiq));
1256 if (err)
1257 goto err_unlock;
1258
1259 err = -ENODEV;
1260 if (!fiq->connected)
1261 goto err_unlock;
1262
1263 if (!list_empty(&fiq->interrupts)) {
1264 req = list_entry(fiq->interrupts.next, struct fuse_req,
1265 intr_entry);
1266 return fuse_read_interrupt(fiq, cs, nbytes, req);
1267 }
1268
1269 if (forget_pending(fiq)) {
1270 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1271 return fuse_read_forget(fc, fiq, cs, nbytes);
1272
1273 if (fiq->forget_batch <= -8)
1274 fiq->forget_batch = 16;
1275 }
1276
1277 req = list_entry(fiq->pending.next, struct fuse_req, list);
1278 clear_bit(FR_PENDING, &req->flags);
1279 list_del_init(&req->list);
1280 spin_unlock(&fiq->waitq.lock);
1281
1282 spin_lock(&fc->lock);
1283 list_add(&req->list, &fpq->io);
1284
1285 in = &req->in;
1286 reqsize = in->h.len;
1287 /* If request is too large, reply with an error and restart the read */
1288 if (nbytes < reqsize) {
1289 req->out.h.error = -EIO;
1290 /* SETXATTR is special, since it may contain too large data */
1291 if (in->h.opcode == FUSE_SETXATTR)
1292 req->out.h.error = -E2BIG;
1293 list_del_init(&req->list);
1294 request_end(fc, req);
1295 goto restart;
1296 }
1297 spin_unlock(&fc->lock);
1298 cs->req = req;
1299 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1300 if (!err)
1301 err = fuse_copy_args(cs, in->numargs, in->argpages,
1302 (struct fuse_arg *) in->args, 0);
1303 fuse_copy_finish(cs);
1304 spin_lock(&fc->lock);
1305 clear_bit(FR_LOCKED, &req->flags);
1306 if (!fpq->connected) {
1307 list_del_init(&req->list);
1308 request_end(fc, req);
1309 return -ENODEV;
1310 }
1311 if (err) {
1312 req->out.h.error = -EIO;
1313 list_del_init(&req->list);
1314 request_end(fc, req);
1315 return err;
1316 }
1317 if (!test_bit(FR_ISREPLY, &req->flags)) {
1318 list_del_init(&req->list);
1319 request_end(fc, req);
1320 } else {
1321 list_move_tail(&req->list, &fpq->processing);
1322 set_bit(FR_SENT, &req->flags);
1323 /* matches barrier in request_wait_answer() */
1324 smp_mb__after_atomic();
1325 if (test_bit(FR_INTERRUPTED, &req->flags))
1326 queue_interrupt(fiq, req);
1327 spin_unlock(&fc->lock);
1328 }
1329 return reqsize;
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(&fc->lock);
1896 err = -ENOENT;
1897 if (!fpq->connected)
1898 goto err_unlock;
1899
1900 req = request_find(fpq, oh.unique);
1901 if (!req)
1902 goto err_unlock;
1903
1904 /* Is it an interrupt reply? */
1905 if (req->intr_unique == oh.unique) {
1906 err = -EINVAL;
1907 if (nbytes != sizeof(struct fuse_out_header))
1908 goto err_unlock;
1909
1910 if (oh.error == -ENOSYS)
1911 fc->no_interrupt = 1;
1912 else if (oh.error == -EAGAIN)
1913 queue_interrupt(&fc->iq, req);
1914
1915 spin_unlock(&fc->lock);
1916 fuse_copy_finish(cs);
1917 return nbytes;
1918 }
1919
1920 clear_bit(FR_SENT, &req->flags);
1921 list_move(&req->list, &fpq->io);
1922 req->out.h = oh;
1923 set_bit(FR_LOCKED, &req->flags);
1924 cs->req = req;
1925 if (!req->out.page_replace)
1926 cs->move_pages = 0;
1927 spin_unlock(&fc->lock);
1928
1929 err = copy_out_args(cs, &req->out, nbytes);
1930 fuse_copy_finish(cs);
1931
1932 spin_lock(&fc->lock);
1933 clear_bit(FR_LOCKED, &req->flags);
1934 if (!fpq->connected)
1935 err = -ENOENT;
1936 else if (err)
1937 req->out.h.error = -EIO;
1938 list_del_init(&req->list);
1939 request_end(fc, req);
1940
1941 return err ? err : nbytes;
1942
1943 err_unlock:
1944 spin_unlock(&fc->lock);
1945 err_finish:
1946 fuse_copy_finish(cs);
1947 return err;
1948 }
1949
1950 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1951 {
1952 struct fuse_copy_state cs;
1953 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1954 if (!fc)
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(fc, &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_conn *fc;
1974 size_t rem;
1975 ssize_t ret;
1976
1977 fc = fuse_get_conn(out);
1978 if (!fc)
1979 return -EPERM;
1980
1981 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1982 if (!bufs)
1983 return -ENOMEM;
1984
1985 pipe_lock(pipe);
1986 nbuf = 0;
1987 rem = 0;
1988 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1989 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1990
1991 ret = -EINVAL;
1992 if (rem < len) {
1993 pipe_unlock(pipe);
1994 goto out;
1995 }
1996
1997 rem = len;
1998 while (rem) {
1999 struct pipe_buffer *ibuf;
2000 struct pipe_buffer *obuf;
2001
2002 BUG_ON(nbuf >= pipe->buffers);
2003 BUG_ON(!pipe->nrbufs);
2004 ibuf = &pipe->bufs[pipe->curbuf];
2005 obuf = &bufs[nbuf];
2006
2007 if (rem >= ibuf->len) {
2008 *obuf = *ibuf;
2009 ibuf->ops = NULL;
2010 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2011 pipe->nrbufs--;
2012 } else {
2013 ibuf->ops->get(pipe, ibuf);
2014 *obuf = *ibuf;
2015 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2016 obuf->len = rem;
2017 ibuf->offset += obuf->len;
2018 ibuf->len -= obuf->len;
2019 }
2020 nbuf++;
2021 rem -= obuf->len;
2022 }
2023 pipe_unlock(pipe);
2024
2025 fuse_copy_init(&cs, 0, NULL);
2026 cs.pipebufs = bufs;
2027 cs.nr_segs = nbuf;
2028 cs.pipe = pipe;
2029
2030 if (flags & SPLICE_F_MOVE)
2031 cs.move_pages = 1;
2032
2033 ret = fuse_dev_do_write(fc, &cs, len);
2034
2035 for (idx = 0; idx < nbuf; idx++) {
2036 struct pipe_buffer *buf = &bufs[idx];
2037 buf->ops->release(pipe, buf);
2038 }
2039 out:
2040 kfree(bufs);
2041 return ret;
2042 }
2043
2044 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2045 {
2046 unsigned mask = POLLOUT | POLLWRNORM;
2047 struct fuse_iqueue *fiq;
2048 struct fuse_conn *fc = fuse_get_conn(file);
2049 if (!fc)
2050 return POLLERR;
2051
2052 fiq = &fc->iq;
2053 poll_wait(file, &fiq->waitq, wait);
2054
2055 spin_lock(&fiq->waitq.lock);
2056 if (!fiq->connected)
2057 mask = POLLERR;
2058 else if (request_pending(fiq))
2059 mask |= POLLIN | POLLRDNORM;
2060 spin_unlock(&fiq->waitq.lock);
2061
2062 return mask;
2063 }
2064
2065 /*
2066 * Abort all requests on the given list (pending or processing)
2067 *
2068 * This function releases and reacquires fc->lock
2069 */
2070 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2071 __releases(fc->lock)
2072 __acquires(fc->lock)
2073 {
2074 while (!list_empty(head)) {
2075 struct fuse_req *req;
2076 req = list_entry(head->next, struct fuse_req, list);
2077 req->out.h.error = -ECONNABORTED;
2078 clear_bit(FR_PENDING, &req->flags);
2079 clear_bit(FR_SENT, &req->flags);
2080 list_del_init(&req->list);
2081 request_end(fc, req);
2082 spin_lock(&fc->lock);
2083 }
2084 }
2085
2086 static void end_polls(struct fuse_conn *fc)
2087 {
2088 struct rb_node *p;
2089
2090 p = rb_first(&fc->polled_files);
2091
2092 while (p) {
2093 struct fuse_file *ff;
2094 ff = rb_entry(p, struct fuse_file, polled_node);
2095 wake_up_interruptible_all(&ff->poll_wait);
2096
2097 p = rb_next(p);
2098 }
2099 }
2100
2101 /*
2102 * Abort all requests.
2103 *
2104 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2105 * filesystem.
2106 *
2107 * The same effect is usually achievable through killing the filesystem daemon
2108 * and all users of the filesystem. The exception is the combination of an
2109 * asynchronous request and the tricky deadlock (see
2110 * Documentation/filesystems/fuse.txt).
2111 *
2112 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2113 * requests, they should be finished off immediately. Locked requests will be
2114 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2115 * requests. It is possible that some request will finish before we can. This
2116 * is OK, the request will in that case be removed from the list before we touch
2117 * it.
2118 */
2119 void fuse_abort_conn(struct fuse_conn *fc)
2120 {
2121 struct fuse_iqueue *fiq = &fc->iq;
2122 struct fuse_pqueue *fpq = &fc->pq;
2123
2124 spin_lock(&fc->lock);
2125 if (fc->connected) {
2126 struct fuse_req *req, *next;
2127 LIST_HEAD(to_end1);
2128 LIST_HEAD(to_end2);
2129
2130 fc->connected = 0;
2131 fc->blocked = 0;
2132 fuse_set_initialized(fc);
2133 fpq->connected = 0;
2134 list_for_each_entry_safe(req, next, &fpq->io, list) {
2135 req->out.h.error = -ECONNABORTED;
2136 spin_lock(&req->waitq.lock);
2137 set_bit(FR_ABORTED, &req->flags);
2138 if (!test_bit(FR_LOCKED, &req->flags))
2139 list_move(&req->list, &to_end1);
2140 spin_unlock(&req->waitq.lock);
2141 }
2142 fc->max_background = UINT_MAX;
2143 flush_bg_queue(fc);
2144
2145 spin_lock(&fiq->waitq.lock);
2146 fiq->connected = 0;
2147 list_splice_init(&fiq->pending, &to_end2);
2148 while (forget_pending(fiq))
2149 kfree(dequeue_forget(fiq, 1, NULL));
2150 wake_up_all_locked(&fiq->waitq);
2151 spin_unlock(&fiq->waitq.lock);
2152 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2153
2154 list_splice_init(&fpq->processing, &to_end2);
2155 while (!list_empty(&to_end1)) {
2156 req = list_first_entry(&to_end1, struct fuse_req, list);
2157 __fuse_get_request(req);
2158 list_del_init(&req->list);
2159 request_end(fc, req);
2160 spin_lock(&fc->lock);
2161 }
2162 end_requests(fc, &to_end2);
2163 end_polls(fc);
2164 wake_up_all(&fc->blocked_waitq);
2165 }
2166 spin_unlock(&fc->lock);
2167 }
2168 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2169
2170 int fuse_dev_release(struct inode *inode, struct file *file)
2171 {
2172 struct fuse_conn *fc = fuse_get_conn(file);
2173 if (fc) {
2174 WARN_ON(!list_empty(&fc->pq.io));
2175 WARN_ON(fc->iq.fasync != NULL);
2176 fuse_abort_conn(fc);
2177 fuse_conn_put(fc);
2178 }
2179
2180 return 0;
2181 }
2182 EXPORT_SYMBOL_GPL(fuse_dev_release);
2183
2184 static int fuse_dev_fasync(int fd, struct file *file, int on)
2185 {
2186 struct fuse_conn *fc = fuse_get_conn(file);
2187 if (!fc)
2188 return -EPERM;
2189
2190 /* No locking - fasync_helper does its own locking */
2191 return fasync_helper(fd, file, on, &fc->iq.fasync);
2192 }
2193
2194 const struct file_operations fuse_dev_operations = {
2195 .owner = THIS_MODULE,
2196 .open = fuse_dev_open,
2197 .llseek = no_llseek,
2198 .read_iter = fuse_dev_read,
2199 .splice_read = fuse_dev_splice_read,
2200 .write_iter = fuse_dev_write,
2201 .splice_write = fuse_dev_splice_write,
2202 .poll = fuse_dev_poll,
2203 .release = fuse_dev_release,
2204 .fasync = fuse_dev_fasync,
2205 };
2206 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2207
2208 static struct miscdevice fuse_miscdevice = {
2209 .minor = FUSE_MINOR,
2210 .name = "fuse",
2211 .fops = &fuse_dev_operations,
2212 };
2213
2214 int __init fuse_dev_init(void)
2215 {
2216 int err = -ENOMEM;
2217 fuse_req_cachep = kmem_cache_create("fuse_request",
2218 sizeof(struct fuse_req),
2219 0, 0, NULL);
2220 if (!fuse_req_cachep)
2221 goto out;
2222
2223 err = misc_register(&fuse_miscdevice);
2224 if (err)
2225 goto out_cache_clean;
2226
2227 return 0;
2228
2229 out_cache_clean:
2230 kmem_cache_destroy(fuse_req_cachep);
2231 out:
2232 return err;
2233 }
2234
2235 void fuse_dev_cleanup(void)
2236 {
2237 misc_deregister(&fuse_miscdevice);
2238 kmem_cache_destroy(fuse_req_cachep);
2239 }
Linux kernel - Deliverables
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