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i2c: fsi: Add I2C master locking
[linux/fpc-iii.git] / fs / fuse / dev.c
blobc6b88fa85e2e5d048ea49b268c402843d53c2c0e
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/sched/signal.h>
15 #include <linux/uio.h>
16 #include <linux/miscdevice.h>
17 #include <linux/pagemap.h>
18 #include <linux/file.h>
19 #include <linux/slab.h>
20 #include <linux/pipe_fs_i.h>
21 #include <linux/swap.h>
22 #include <linux/splice.h>
23 #include <linux/sched.h>
24
25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26 MODULE_ALIAS("devname:fuse");
27
28 static struct kmem_cache *fuse_req_cachep;
29
30 static struct fuse_dev *fuse_get_dev(struct file *file)
31 {
32 /*
33 * Lockless access is OK, because file->private data is set
34 * once during mount and is valid until the file is released.
35 */
36 return READ_ONCE(file->private_data);
37 }
38
39 static void fuse_request_init(struct fuse_req *req, struct page **pages,
40 struct fuse_page_desc *page_descs,
41 unsigned npages)
42 {
43 memset(req, 0, sizeof(*req));
44 memset(pages, 0, sizeof(*pages) * npages);
45 memset(page_descs, 0, sizeof(*page_descs) * npages);
46 INIT_LIST_HEAD(&req->list);
47 INIT_LIST_HEAD(&req->intr_entry);
48 init_waitqueue_head(&req->waitq);
49 refcount_set(&req->count, 1);
50 req->pages = pages;
51 req->page_descs = page_descs;
52 req->max_pages = npages;
53 __set_bit(FR_PENDING, &req->flags);
54 }
55
56 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
57 {
58 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
59 if (req) {
60 struct page **pages;
61 struct fuse_page_desc *page_descs;
62
63 if (npages <= FUSE_REQ_INLINE_PAGES) {
64 pages = req->inline_pages;
65 page_descs = req->inline_page_descs;
66 } else {
67 pages = kmalloc_array(npages, sizeof(struct page *),
68 flags);
69 page_descs =
70 kmalloc_array(npages,
71 sizeof(struct fuse_page_desc),
72 flags);
73 }
74
75 if (!pages || !page_descs) {
76 kfree(pages);
77 kfree(page_descs);
78 kmem_cache_free(fuse_req_cachep, req);
79 return NULL;
80 }
81
82 fuse_request_init(req, pages, page_descs, npages);
83 }
84 return req;
85 }
86
87 struct fuse_req *fuse_request_alloc(unsigned npages)
88 {
89 return __fuse_request_alloc(npages, GFP_KERNEL);
90 }
91 EXPORT_SYMBOL_GPL(fuse_request_alloc);
92
93 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
94 {
95 return __fuse_request_alloc(npages, GFP_NOFS);
96 }
97
98 void fuse_request_free(struct fuse_req *req)
99 {
100 if (req->pages != req->inline_pages) {
101 kfree(req->pages);
102 kfree(req->page_descs);
103 }
104 kmem_cache_free(fuse_req_cachep, req);
105 }
106
107 void __fuse_get_request(struct fuse_req *req)
108 {
109 refcount_inc(&req->count);
110 }
111
112 /* Must be called with > 1 refcount */
113 static void __fuse_put_request(struct fuse_req *req)
114 {
115 refcount_dec(&req->count);
116 }
117
118 void fuse_set_initialized(struct fuse_conn *fc)
119 {
120 /* Make sure stores before this are seen on another CPU */
121 smp_wmb();
122 fc->initialized = 1;
123 }
124
125 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
126 {
127 return !fc->initialized || (for_background && fc->blocked);
128 }
129
130 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
131 bool for_background)
132 {
133 struct fuse_req *req;
134 int err;
135 atomic_inc(&fc->num_waiting);
136
137 if (fuse_block_alloc(fc, for_background)) {
138 err = -EINTR;
139 if (wait_event_killable_exclusive(fc->blocked_waitq,
140 !fuse_block_alloc(fc, for_background)))
141 goto out;
142 }
143 /* Matches smp_wmb() in fuse_set_initialized() */
144 smp_rmb();
145
146 err = -ENOTCONN;
147 if (!fc->connected)
148 goto out;
149
150 err = -ECONNREFUSED;
151 if (fc->conn_error)
152 goto out;
153
154 req = fuse_request_alloc(npages);
155 err = -ENOMEM;
156 if (!req) {
157 if (for_background)
158 wake_up(&fc->blocked_waitq);
159 goto out;
160 }
161
162 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
163 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
164 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
165
166 __set_bit(FR_WAITING, &req->flags);
167 if (for_background)
168 __set_bit(FR_BACKGROUND, &req->flags);
169
170 if (unlikely(req->in.h.uid == ((uid_t)-1) ||
171 req->in.h.gid == ((gid_t)-1))) {
172 fuse_put_request(fc, req);
173 return ERR_PTR(-EOVERFLOW);
174 }
175 return req;
176
177 out:
178 atomic_dec(&fc->num_waiting);
179 return ERR_PTR(err);
180 }
181
182 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
183 {
184 return __fuse_get_req(fc, npages, false);
185 }
186 EXPORT_SYMBOL_GPL(fuse_get_req);
187
188 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
189 unsigned npages)
190 {
191 return __fuse_get_req(fc, npages, true);
192 }
193 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
194
195 /*
196 * Return request in fuse_file->reserved_req. However that may
197 * currently be in use. If that is the case, wait for it to become
198 * available.
199 */
200 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
201 struct file *file)
202 {
203 struct fuse_req *req = NULL;
204 struct fuse_file *ff = file->private_data;
205
206 do {
207 wait_event(fc->reserved_req_waitq, ff->reserved_req);
208 spin_lock(&fc->lock);
209 if (ff->reserved_req) {
210 req = ff->reserved_req;
211 ff->reserved_req = NULL;
212 req->stolen_file = get_file(file);
213 }
214 spin_unlock(&fc->lock);
215 } while (!req);
216
217 return req;
218 }
219
220 /*
221 * Put stolen request back into fuse_file->reserved_req
222 */
223 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
224 {
225 struct file *file = req->stolen_file;
226 struct fuse_file *ff = file->private_data;
227
228 spin_lock(&fc->lock);
229 fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
230 BUG_ON(ff->reserved_req);
231 ff->reserved_req = req;
232 wake_up_all(&fc->reserved_req_waitq);
233 spin_unlock(&fc->lock);
234 fput(file);
235 }
236
237 /*
238 * Gets a requests for a file operation, always succeeds
239 *
240 * This is used for sending the FLUSH request, which must get to
241 * userspace, due to POSIX locks which may need to be unlocked.
242 *
243 * If allocation fails due to OOM, use the reserved request in
244 * fuse_file.
245 *
246 * This is very unlikely to deadlock accidentally, since the
247 * filesystem should not have it's own file open. If deadlock is
248 * intentional, it can still be broken by "aborting" the filesystem.
249 */
250 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
251 struct file *file)
252 {
253 struct fuse_req *req;
254
255 atomic_inc(&fc->num_waiting);
256 wait_event(fc->blocked_waitq, fc->initialized);
257 /* Matches smp_wmb() in fuse_set_initialized() */
258 smp_rmb();
259 req = fuse_request_alloc(0);
260 if (!req)
261 req = get_reserved_req(fc, file);
262
263 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
264 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
265 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
266
267 __set_bit(FR_WAITING, &req->flags);
268 __clear_bit(FR_BACKGROUND, &req->flags);
269 return req;
270 }
271
272 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
273 {
274 if (refcount_dec_and_test(&req->count)) {
275 if (test_bit(FR_BACKGROUND, &req->flags)) {
276 /*
277 * We get here in the unlikely case that a background
278 * request was allocated but not sent
279 */
280 spin_lock(&fc->lock);
281 if (!fc->blocked)
282 wake_up(&fc->blocked_waitq);
283 spin_unlock(&fc->lock);
284 }
285
286 if (test_bit(FR_WAITING, &req->flags)) {
287 __clear_bit(FR_WAITING, &req->flags);
288 atomic_dec(&fc->num_waiting);
289 }
290
291 if (req->stolen_file)
292 put_reserved_req(fc, req);
293 else
294 fuse_request_free(req);
295 }
296 }
297 EXPORT_SYMBOL_GPL(fuse_put_request);
298
299 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
300 {
301 unsigned nbytes = 0;
302 unsigned i;
303
304 for (i = 0; i < numargs; i++)
305 nbytes += args[i].size;
306
307 return nbytes;
308 }
309
310 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
311 {
312 return ++fiq->reqctr;
313 }
314
315 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
316 {
317 req->in.h.len = sizeof(struct fuse_in_header) +
318 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
319 list_add_tail(&req->list, &fiq->pending);
320 wake_up_locked(&fiq->waitq);
321 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
322 }
323
324 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
325 u64 nodeid, u64 nlookup)
326 {
327 struct fuse_iqueue *fiq = &fc->iq;
328
329 forget->forget_one.nodeid = nodeid;
330 forget->forget_one.nlookup = nlookup;
331
332 spin_lock(&fiq->waitq.lock);
333 if (fiq->connected) {
334 fiq->forget_list_tail->next = forget;
335 fiq->forget_list_tail = forget;
336 wake_up_locked(&fiq->waitq);
337 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
338 } else {
339 kfree(forget);
340 }
341 spin_unlock(&fiq->waitq.lock);
342 }
343
344 static void flush_bg_queue(struct fuse_conn *fc)
345 {
346 while (fc->active_background < fc->max_background &&
347 !list_empty(&fc->bg_queue)) {
348 struct fuse_req *req;
349 struct fuse_iqueue *fiq = &fc->iq;
350
351 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
352 list_del(&req->list);
353 fc->active_background++;
354 spin_lock(&fiq->waitq.lock);
355 req->in.h.unique = fuse_get_unique(fiq);
356 queue_request(fiq, req);
357 spin_unlock(&fiq->waitq.lock);
358 }
359 }
360
361 /*
362 * This function is called when a request is finished. Either a reply
363 * has arrived or it was aborted (and not yet sent) or some error
364 * occurred during communication with userspace, or the device file
365 * was closed. The requester thread is woken up (if still waiting),
366 * the 'end' callback is called if given, else the reference to the
367 * request is released
368 */
369 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
370 {
371 struct fuse_iqueue *fiq = &fc->iq;
372
373 if (test_and_set_bit(FR_FINISHED, &req->flags))
374 return;
375
376 spin_lock(&fiq->waitq.lock);
377 list_del_init(&req->intr_entry);
378 spin_unlock(&fiq->waitq.lock);
379 WARN_ON(test_bit(FR_PENDING, &req->flags));
380 WARN_ON(test_bit(FR_SENT, &req->flags));
381 if (test_bit(FR_BACKGROUND, &req->flags)) {
382 spin_lock(&fc->lock);
383 clear_bit(FR_BACKGROUND, &req->flags);
384 if (fc->num_background == fc->max_background)
385 fc->blocked = 0;
386
387 /* Wake up next waiter, if any */
388 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
389 wake_up(&fc->blocked_waitq);
390
391 if (fc->num_background == fc->congestion_threshold && fc->sb) {
392 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
393 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
394 }
395 fc->num_background--;
396 fc->active_background--;
397 flush_bg_queue(fc);
398 spin_unlock(&fc->lock);
399 }
400 wake_up(&req->waitq);
401 if (req->end)
402 req->end(fc, req);
403 fuse_put_request(fc, req);
404 }
405
406 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
407 {
408 spin_lock(&fiq->waitq.lock);
409 if (test_bit(FR_FINISHED, &req->flags)) {
410 spin_unlock(&fiq->waitq.lock);
411 return;
412 }
413 if (list_empty(&req->intr_entry)) {
414 list_add_tail(&req->intr_entry, &fiq->interrupts);
415 wake_up_locked(&fiq->waitq);
416 }
417 spin_unlock(&fiq->waitq.lock);
418 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
419 }
420
421 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
422 {
423 struct fuse_iqueue *fiq = &fc->iq;
424 int err;
425
426 if (!fc->no_interrupt) {
427 /* Any signal may interrupt this */
428 err = wait_event_interruptible(req->waitq,
429 test_bit(FR_FINISHED, &req->flags));
430 if (!err)
431 return;
432
433 set_bit(FR_INTERRUPTED, &req->flags);
434 /* matches barrier in fuse_dev_do_read() */
435 smp_mb__after_atomic();
436 if (test_bit(FR_SENT, &req->flags))
437 queue_interrupt(fiq, req);
438 }
439
440 if (!test_bit(FR_FORCE, &req->flags)) {
441 /* Only fatal signals may interrupt this */
442 err = wait_event_killable(req->waitq,
443 test_bit(FR_FINISHED, &req->flags));
444 if (!err)
445 return;
446
447 spin_lock(&fiq->waitq.lock);
448 /* Request is not yet in userspace, bail out */
449 if (test_bit(FR_PENDING, &req->flags)) {
450 list_del(&req->list);
451 spin_unlock(&fiq->waitq.lock);
452 __fuse_put_request(req);
453 req->out.h.error = -EINTR;
454 return;
455 }
456 spin_unlock(&fiq->waitq.lock);
457 }
458
459 /*
460 * Either request is already in userspace, or it was forced.
461 * Wait it out.
462 */
463 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
464 }
465
466 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
467 {
468 struct fuse_iqueue *fiq = &fc->iq;
469
470 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
471 spin_lock(&fiq->waitq.lock);
472 if (!fiq->connected) {
473 spin_unlock(&fiq->waitq.lock);
474 req->out.h.error = -ENOTCONN;
475 } else {
476 req->in.h.unique = fuse_get_unique(fiq);
477 queue_request(fiq, req);
478 /* acquire extra reference, since request is still needed
479 after request_end() */
480 __fuse_get_request(req);
481 spin_unlock(&fiq->waitq.lock);
482
483 request_wait_answer(fc, req);
484 /* Pairs with smp_wmb() in request_end() */
485 smp_rmb();
486 }
487 }
488
489 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
490 {
491 __set_bit(FR_ISREPLY, &req->flags);
492 if (!test_bit(FR_WAITING, &req->flags)) {
493 __set_bit(FR_WAITING, &req->flags);
494 atomic_inc(&fc->num_waiting);
495 }
496 __fuse_request_send(fc, req);
497 }
498 EXPORT_SYMBOL_GPL(fuse_request_send);
499
500 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
501 {
502 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
503 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
504
505 if (fc->minor < 9) {
506 switch (args->in.h.opcode) {
507 case FUSE_LOOKUP:
508 case FUSE_CREATE:
509 case FUSE_MKNOD:
510 case FUSE_MKDIR:
511 case FUSE_SYMLINK:
512 case FUSE_LINK:
513 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
514 break;
515 case FUSE_GETATTR:
516 case FUSE_SETATTR:
517 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
518 break;
519 }
520 }
521 if (fc->minor < 12) {
522 switch (args->in.h.opcode) {
523 case FUSE_CREATE:
524 args->in.args[0].size = sizeof(struct fuse_open_in);
525 break;
526 case FUSE_MKNOD:
527 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
528 break;
529 }
530 }
531 }
532
533 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
534 {
535 struct fuse_req *req;
536 ssize_t ret;
537
538 req = fuse_get_req(fc, 0);
539 if (IS_ERR(req))
540 return PTR_ERR(req);
541
542 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
543 fuse_adjust_compat(fc, args);
544
545 req->in.h.opcode = args->in.h.opcode;
546 req->in.h.nodeid = args->in.h.nodeid;
547 req->in.numargs = args->in.numargs;
548 memcpy(req->in.args, args->in.args,
549 args->in.numargs * sizeof(struct fuse_in_arg));
550 req->out.argvar = args->out.argvar;
551 req->out.numargs = args->out.numargs;
552 memcpy(req->out.args, args->out.args,
553 args->out.numargs * sizeof(struct fuse_arg));
554 fuse_request_send(fc, req);
555 ret = req->out.h.error;
556 if (!ret && args->out.argvar) {
557 BUG_ON(args->out.numargs != 1);
558 ret = req->out.args[0].size;
559 }
560 fuse_put_request(fc, req);
561
562 return ret;
563 }
564
565 /*
566 * Called under fc->lock
567 *
568 * fc->connected must have been checked previously
569 */
570 void fuse_request_send_background_locked(struct fuse_conn *fc,
571 struct fuse_req *req)
572 {
573 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
574 if (!test_bit(FR_WAITING, &req->flags)) {
575 __set_bit(FR_WAITING, &req->flags);
576 atomic_inc(&fc->num_waiting);
577 }
578 __set_bit(FR_ISREPLY, &req->flags);
579 fc->num_background++;
580 if (fc->num_background == fc->max_background)
581 fc->blocked = 1;
582 if (fc->num_background == fc->congestion_threshold && fc->sb) {
583 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
584 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
585 }
586 list_add_tail(&req->list, &fc->bg_queue);
587 flush_bg_queue(fc);
588 }
589
590 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
591 {
592 BUG_ON(!req->end);
593 spin_lock(&fc->lock);
594 if (fc->connected) {
595 fuse_request_send_background_locked(fc, req);
596 spin_unlock(&fc->lock);
597 } else {
598 spin_unlock(&fc->lock);
599 req->out.h.error = -ENOTCONN;
600 req->end(fc, req);
601 fuse_put_request(fc, req);
602 }
603 }
604 EXPORT_SYMBOL_GPL(fuse_request_send_background);
605
606 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
607 struct fuse_req *req, u64 unique)
608 {
609 int err = -ENODEV;
610 struct fuse_iqueue *fiq = &fc->iq;
611
612 __clear_bit(FR_ISREPLY, &req->flags);
613 req->in.h.unique = unique;
614 spin_lock(&fiq->waitq.lock);
615 if (fiq->connected) {
616 queue_request(fiq, req);
617 err = 0;
618 }
619 spin_unlock(&fiq->waitq.lock);
620
621 return err;
622 }
623
624 void fuse_force_forget(struct file *file, u64 nodeid)
625 {
626 struct inode *inode = file_inode(file);
627 struct fuse_conn *fc = get_fuse_conn(inode);
628 struct fuse_req *req;
629 struct fuse_forget_in inarg;
630
631 memset(&inarg, 0, sizeof(inarg));
632 inarg.nlookup = 1;
633 req = fuse_get_req_nofail_nopages(fc, file);
634 req->in.h.opcode = FUSE_FORGET;
635 req->in.h.nodeid = nodeid;
636 req->in.numargs = 1;
637 req->in.args[0].size = sizeof(inarg);
638 req->in.args[0].value = &inarg;
639 __clear_bit(FR_ISREPLY, &req->flags);
640 __fuse_request_send(fc, req);
641 /* ignore errors */
642 fuse_put_request(fc, req);
643 }
644
645 /*
646 * Lock the request. Up to the next unlock_request() there mustn't be
647 * anything that could cause a page-fault. If the request was already
648 * aborted bail out.
649 */
650 static int lock_request(struct fuse_req *req)
651 {
652 int err = 0;
653 if (req) {
654 spin_lock(&req->waitq.lock);
655 if (test_bit(FR_ABORTED, &req->flags))
656 err = -ENOENT;
657 else
658 set_bit(FR_LOCKED, &req->flags);
659 spin_unlock(&req->waitq.lock);
660 }
661 return err;
662 }
663
664 /*
665 * Unlock request. If it was aborted while locked, caller is responsible
666 * for unlocking and ending the request.
667 */
668 static int unlock_request(struct fuse_req *req)
669 {
670 int err = 0;
671 if (req) {
672 spin_lock(&req->waitq.lock);
673 if (test_bit(FR_ABORTED, &req->flags))
674 err = -ENOENT;
675 else
676 clear_bit(FR_LOCKED, &req->flags);
677 spin_unlock(&req->waitq.lock);
678 }
679 return err;
680 }
681
682 struct fuse_copy_state {
683 int write;
684 struct fuse_req *req;
685 struct iov_iter *iter;
686 struct pipe_buffer *pipebufs;
687 struct pipe_buffer *currbuf;
688 struct pipe_inode_info *pipe;
689 unsigned long nr_segs;
690 struct page *pg;
691 unsigned len;
692 unsigned offset;
693 unsigned move_pages:1;
694 };
695
696 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
697 struct iov_iter *iter)
698 {
699 memset(cs, 0, sizeof(*cs));
700 cs->write = write;
701 cs->iter = iter;
702 }
703
704 /* Unmap and put previous page of userspace buffer */
705 static void fuse_copy_finish(struct fuse_copy_state *cs)
706 {
707 if (cs->currbuf) {
708 struct pipe_buffer *buf = cs->currbuf;
709
710 if (cs->write)
711 buf->len = PAGE_SIZE - cs->len;
712 cs->currbuf = NULL;
713 } else if (cs->pg) {
714 if (cs->write) {
715 flush_dcache_page(cs->pg);
716 set_page_dirty_lock(cs->pg);
717 }
718 put_page(cs->pg);
719 }
720 cs->pg = NULL;
721 }
722
723 /*
724 * Get another pagefull of userspace buffer, and map it to kernel
725 * address space, and lock request
726 */
727 static int fuse_copy_fill(struct fuse_copy_state *cs)
728 {
729 struct page *page;
730 int err;
731
732 err = unlock_request(cs->req);
733 if (err)
734 return err;
735
736 fuse_copy_finish(cs);
737 if (cs->pipebufs) {
738 struct pipe_buffer *buf = cs->pipebufs;
739
740 if (!cs->write) {
741 err = pipe_buf_confirm(cs->pipe, buf);
742 if (err)
743 return err;
744
745 BUG_ON(!cs->nr_segs);
746 cs->currbuf = buf;
747 cs->pg = buf->page;
748 cs->offset = buf->offset;
749 cs->len = buf->len;
750 cs->pipebufs++;
751 cs->nr_segs--;
752 } else {
753 if (cs->nr_segs == cs->pipe->buffers)
754 return -EIO;
755
756 page = alloc_page(GFP_HIGHUSER);
757 if (!page)
758 return -ENOMEM;
759
760 buf->page = page;
761 buf->offset = 0;
762 buf->len = 0;
763
764 cs->currbuf = buf;
765 cs->pg = page;
766 cs->offset = 0;
767 cs->len = PAGE_SIZE;
768 cs->pipebufs++;
769 cs->nr_segs++;
770 }
771 } else {
772 size_t off;
773 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
774 if (err < 0)
775 return err;
776 BUG_ON(!err);
777 cs->len = err;
778 cs->offset = off;
779 cs->pg = page;
780 iov_iter_advance(cs->iter, err);
781 }
782
783 return lock_request(cs->req);
784 }
785
786 /* Do as much copy to/from userspace buffer as we can */
787 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
788 {
789 unsigned ncpy = min(*size, cs->len);
790 if (val) {
791 void *pgaddr = kmap_atomic(cs->pg);
792 void *buf = pgaddr + cs->offset;
793
794 if (cs->write)
795 memcpy(buf, *val, ncpy);
796 else
797 memcpy(*val, buf, ncpy);
798
799 kunmap_atomic(pgaddr);
800 *val += ncpy;
801 }
802 *size -= ncpy;
803 cs->len -= ncpy;
804 cs->offset += ncpy;
805 return ncpy;
806 }
807
808 static int fuse_check_page(struct page *page)
809 {
810 if (page_mapcount(page) ||
811 page->mapping != NULL ||
812 page_count(page) != 1 ||
813 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
814 ~(1 << PG_locked |
815 1 << PG_referenced |
816 1 << PG_uptodate |
817 1 << PG_lru |
818 1 << PG_active |
819 1 << PG_reclaim))) {
820 printk(KERN_WARNING "fuse: trying to steal weird page\n");
821 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);
822 return 1;
823 }
824 return 0;
825 }
826
827 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
828 {
829 int err;
830 struct page *oldpage = *pagep;
831 struct page *newpage;
832 struct pipe_buffer *buf = cs->pipebufs;
833
834 err = unlock_request(cs->req);
835 if (err)
836 return err;
837
838 fuse_copy_finish(cs);
839
840 err = pipe_buf_confirm(cs->pipe, buf);
841 if (err)
842 return err;
843
844 BUG_ON(!cs->nr_segs);
845 cs->currbuf = buf;
846 cs->len = buf->len;
847 cs->pipebufs++;
848 cs->nr_segs--;
849
850 if (cs->len != PAGE_SIZE)
851 goto out_fallback;
852
853 if (pipe_buf_steal(cs->pipe, buf) != 0)
854 goto out_fallback;
855
856 newpage = buf->page;
857
858 if (!PageUptodate(newpage))
859 SetPageUptodate(newpage);
860
861 ClearPageMappedToDisk(newpage);
862
863 if (fuse_check_page(newpage) != 0)
864 goto out_fallback_unlock;
865
866 /*
867 * This is a new and locked page, it shouldn't be mapped or
868 * have any special flags on it
869 */
870 if (WARN_ON(page_mapped(oldpage)))
871 goto out_fallback_unlock;
872 if (WARN_ON(page_has_private(oldpage)))
873 goto out_fallback_unlock;
874 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
875 goto out_fallback_unlock;
876 if (WARN_ON(PageMlocked(oldpage)))
877 goto out_fallback_unlock;
878
879 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
880 if (err) {
881 unlock_page(newpage);
882 return err;
883 }
884
885 get_page(newpage);
886
887 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
888 lru_cache_add_file(newpage);
889
890 err = 0;
891 spin_lock(&cs->req->waitq.lock);
892 if (test_bit(FR_ABORTED, &cs->req->flags))
893 err = -ENOENT;
894 else
895 *pagep = newpage;
896 spin_unlock(&cs->req->waitq.lock);
897
898 if (err) {
899 unlock_page(newpage);
900 put_page(newpage);
901 return err;
902 }
903
904 unlock_page(oldpage);
905 put_page(oldpage);
906 cs->len = 0;
907
908 return 0;
909
910 out_fallback_unlock:
911 unlock_page(newpage);
912 out_fallback:
913 cs->pg = buf->page;
914 cs->offset = buf->offset;
915
916 err = lock_request(cs->req);
917 if (err)
918 return err;
919
920 return 1;
921 }
922
923 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
924 unsigned offset, unsigned count)
925 {
926 struct pipe_buffer *buf;
927 int err;
928
929 if (cs->nr_segs == cs->pipe->buffers)
930 return -EIO;
931
932 err = unlock_request(cs->req);
933 if (err)
934 return err;
935
936 fuse_copy_finish(cs);
937
938 buf = cs->pipebufs;
939 get_page(page);
940 buf->page = page;
941 buf->offset = offset;
942 buf->len = count;
943
944 cs->pipebufs++;
945 cs->nr_segs++;
946 cs->len = 0;
947
948 return 0;
949 }
950
951 /*
952 * Copy a page in the request to/from the userspace buffer. Must be
953 * done atomically
954 */
955 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
956 unsigned offset, unsigned count, int zeroing)
957 {
958 int err;
959 struct page *page = *pagep;
960
961 if (page && zeroing && count < PAGE_SIZE)
962 clear_highpage(page);
963
964 while (count) {
965 if (cs->write && cs->pipebufs && page) {
966 return fuse_ref_page(cs, page, offset, count);
967 } else if (!cs->len) {
968 if (cs->move_pages && page &&
969 offset == 0 && count == PAGE_SIZE) {
970 err = fuse_try_move_page(cs, pagep);
971 if (err <= 0)
972 return err;
973 } else {
974 err = fuse_copy_fill(cs);
975 if (err)
976 return err;
977 }
978 }
979 if (page) {
980 void *mapaddr = kmap_atomic(page);
981 void *buf = mapaddr + offset;
982 offset += fuse_copy_do(cs, &buf, &count);
983 kunmap_atomic(mapaddr);
984 } else
985 offset += fuse_copy_do(cs, NULL, &count);
986 }
987 if (page && !cs->write)
988 flush_dcache_page(page);
989 return 0;
990 }
991
992 /* Copy pages in the request to/from userspace buffer */
993 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
994 int zeroing)
995 {
996 unsigned i;
997 struct fuse_req *req = cs->req;
998
999 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1000 int err;
1001 unsigned offset = req->page_descs[i].offset;
1002 unsigned count = min(nbytes, req->page_descs[i].length);
1003
1004 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1005 zeroing);
1006 if (err)
1007 return err;
1008
1009 nbytes -= count;
1010 }
1011 return 0;
1012 }
1013
1014 /* Copy a single argument in the request to/from userspace buffer */
1015 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1016 {
1017 while (size) {
1018 if (!cs->len) {
1019 int err = fuse_copy_fill(cs);
1020 if (err)
1021 return err;
1022 }
1023 fuse_copy_do(cs, &val, &size);
1024 }
1025 return 0;
1026 }
1027
1028 /* Copy request arguments to/from userspace buffer */
1029 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1030 unsigned argpages, struct fuse_arg *args,
1031 int zeroing)
1032 {
1033 int err = 0;
1034 unsigned i;
1035
1036 for (i = 0; !err && i < numargs; i++) {
1037 struct fuse_arg *arg = &args[i];
1038 if (i == numargs - 1 && argpages)
1039 err = fuse_copy_pages(cs, arg->size, zeroing);
1040 else
1041 err = fuse_copy_one(cs, arg->value, arg->size);
1042 }
1043 return err;
1044 }
1045
1046 static int forget_pending(struct fuse_iqueue *fiq)
1047 {
1048 return fiq->forget_list_head.next != NULL;
1049 }
1050
1051 static int request_pending(struct fuse_iqueue *fiq)
1052 {
1053 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1054 forget_pending(fiq);
1055 }
1056
1057 /*
1058 * Transfer an interrupt request to userspace
1059 *
1060 * Unlike other requests this is assembled on demand, without a need
1061 * to allocate a separate fuse_req structure.
1062 *
1063 * Called with fiq->waitq.lock held, releases it
1064 */
1065 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1066 struct fuse_copy_state *cs,
1067 size_t nbytes, struct fuse_req *req)
1068 __releases(fiq->waitq.lock)
1069 {
1070 struct fuse_in_header ih;
1071 struct fuse_interrupt_in arg;
1072 unsigned reqsize = sizeof(ih) + sizeof(arg);
1073 int err;
1074
1075 list_del_init(&req->intr_entry);
1076 req->intr_unique = fuse_get_unique(fiq);
1077 memset(&ih, 0, sizeof(ih));
1078 memset(&arg, 0, sizeof(arg));
1079 ih.len = reqsize;
1080 ih.opcode = FUSE_INTERRUPT;
1081 ih.unique = req->intr_unique;
1082 arg.unique = req->in.h.unique;
1083
1084 spin_unlock(&fiq->waitq.lock);
1085 if (nbytes < reqsize)
1086 return -EINVAL;
1087
1088 err = fuse_copy_one(cs, &ih, sizeof(ih));
1089 if (!err)
1090 err = fuse_copy_one(cs, &arg, sizeof(arg));
1091 fuse_copy_finish(cs);
1092
1093 return err ? err : reqsize;
1094 }
1095
1096 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1097 unsigned max,
1098 unsigned *countp)
1099 {
1100 struct fuse_forget_link *head = fiq->forget_list_head.next;
1101 struct fuse_forget_link **newhead = &head;
1102 unsigned count;
1103
1104 for (count = 0; *newhead != NULL && count < max; count++)
1105 newhead = &(*newhead)->next;
1106
1107 fiq->forget_list_head.next = *newhead;
1108 *newhead = NULL;
1109 if (fiq->forget_list_head.next == NULL)
1110 fiq->forget_list_tail = &fiq->forget_list_head;
1111
1112 if (countp != NULL)
1113 *countp = count;
1114
1115 return head;
1116 }
1117
1118 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1119 struct fuse_copy_state *cs,
1120 size_t nbytes)
1121 __releases(fiq->waitq.lock)
1122 {
1123 int err;
1124 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1125 struct fuse_forget_in arg = {
1126 .nlookup = forget->forget_one.nlookup,
1127 };
1128 struct fuse_in_header ih = {
1129 .opcode = FUSE_FORGET,
1130 .nodeid = forget->forget_one.nodeid,
1131 .unique = fuse_get_unique(fiq),
1132 .len = sizeof(ih) + sizeof(arg),
1133 };
1134
1135 spin_unlock(&fiq->waitq.lock);
1136 kfree(forget);
1137 if (nbytes < ih.len)
1138 return -EINVAL;
1139
1140 err = fuse_copy_one(cs, &ih, sizeof(ih));
1141 if (!err)
1142 err = fuse_copy_one(cs, &arg, sizeof(arg));
1143 fuse_copy_finish(cs);
1144
1145 if (err)
1146 return err;
1147
1148 return ih.len;
1149 }
1150
1151 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1152 struct fuse_copy_state *cs, size_t nbytes)
1153 __releases(fiq->waitq.lock)
1154 {
1155 int err;
1156 unsigned max_forgets;
1157 unsigned count;
1158 struct fuse_forget_link *head;
1159 struct fuse_batch_forget_in arg = { .count = 0 };
1160 struct fuse_in_header ih = {
1161 .opcode = FUSE_BATCH_FORGET,
1162 .unique = fuse_get_unique(fiq),
1163 .len = sizeof(ih) + sizeof(arg),
1164 };
1165
1166 if (nbytes < ih.len) {
1167 spin_unlock(&fiq->waitq.lock);
1168 return -EINVAL;
1169 }
1170
1171 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1172 head = dequeue_forget(fiq, max_forgets, &count);
1173 spin_unlock(&fiq->waitq.lock);
1174
1175 arg.count = count;
1176 ih.len += count * sizeof(struct fuse_forget_one);
1177 err = fuse_copy_one(cs, &ih, sizeof(ih));
1178 if (!err)
1179 err = fuse_copy_one(cs, &arg, sizeof(arg));
1180
1181 while (head) {
1182 struct fuse_forget_link *forget = head;
1183
1184 if (!err) {
1185 err = fuse_copy_one(cs, &forget->forget_one,
1186 sizeof(forget->forget_one));
1187 }
1188 head = forget->next;
1189 kfree(forget);
1190 }
1191
1192 fuse_copy_finish(cs);
1193
1194 if (err)
1195 return err;
1196
1197 return ih.len;
1198 }
1199
1200 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1201 struct fuse_copy_state *cs,
1202 size_t nbytes)
1203 __releases(fiq->waitq.lock)
1204 {
1205 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1206 return fuse_read_single_forget(fiq, cs, nbytes);
1207 else
1208 return fuse_read_batch_forget(fiq, cs, nbytes);
1209 }
1210
1211 /*
1212 * Read a single request into the userspace filesystem's buffer. This
1213 * function waits until a request is available, then removes it from
1214 * the pending list and copies request data to userspace buffer. If
1215 * no reply is needed (FORGET) or request has been aborted or there
1216 * was an error during the copying then it's finished by calling
1217 * request_end(). Otherwise add it to the processing list, and set
1218 * the 'sent' flag.
1219 */
1220 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1221 struct fuse_copy_state *cs, size_t nbytes)
1222 {
1223 ssize_t err;
1224 struct fuse_conn *fc = fud->fc;
1225 struct fuse_iqueue *fiq = &fc->iq;
1226 struct fuse_pqueue *fpq = &fud->pq;
1227 struct fuse_req *req;
1228 struct fuse_in *in;
1229 unsigned reqsize;
1230
1231 restart:
1232 spin_lock(&fiq->waitq.lock);
1233 err = -EAGAIN;
1234 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1235 !request_pending(fiq))
1236 goto err_unlock;
1237
1238 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1239 !fiq->connected || request_pending(fiq));
1240 if (err)
1241 goto err_unlock;
1242
1243 if (!fiq->connected) {
1244 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1245 goto err_unlock;
1246 }
1247
1248 if (!list_empty(&fiq->interrupts)) {
1249 req = list_entry(fiq->interrupts.next, struct fuse_req,
1250 intr_entry);
1251 return fuse_read_interrupt(fiq, cs, nbytes, req);
1252 }
1253
1254 if (forget_pending(fiq)) {
1255 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1256 return fuse_read_forget(fc, fiq, cs, nbytes);
1257
1258 if (fiq->forget_batch <= -8)
1259 fiq->forget_batch = 16;
1260 }
1261
1262 req = list_entry(fiq->pending.next, struct fuse_req, list);
1263 clear_bit(FR_PENDING, &req->flags);
1264 list_del_init(&req->list);
1265 spin_unlock(&fiq->waitq.lock);
1266
1267 in = &req->in;
1268 reqsize = in->h.len;
1269
1270 /* If request is too large, reply with an error and restart the read */
1271 if (nbytes < reqsize) {
1272 req->out.h.error = -EIO;
1273 /* SETXATTR is special, since it may contain too large data */
1274 if (in->h.opcode == FUSE_SETXATTR)
1275 req->out.h.error = -E2BIG;
1276 request_end(fc, req);
1277 goto restart;
1278 }
1279 spin_lock(&fpq->lock);
1280 list_add(&req->list, &fpq->io);
1281 spin_unlock(&fpq->lock);
1282 cs->req = req;
1283 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1284 if (!err)
1285 err = fuse_copy_args(cs, in->numargs, in->argpages,
1286 (struct fuse_arg *) in->args, 0);
1287 fuse_copy_finish(cs);
1288 spin_lock(&fpq->lock);
1289 clear_bit(FR_LOCKED, &req->flags);
1290 if (!fpq->connected) {
1291 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1292 goto out_end;
1293 }
1294 if (err) {
1295 req->out.h.error = -EIO;
1296 goto out_end;
1297 }
1298 if (!test_bit(FR_ISREPLY, &req->flags)) {
1299 err = reqsize;
1300 goto out_end;
1301 }
1302 list_move_tail(&req->list, &fpq->processing);
1303 spin_unlock(&fpq->lock);
1304 set_bit(FR_SENT, &req->flags);
1305 /* matches barrier in request_wait_answer() */
1306 smp_mb__after_atomic();
1307 if (test_bit(FR_INTERRUPTED, &req->flags))
1308 queue_interrupt(fiq, req);
1309
1310 return reqsize;
1311
1312 out_end:
1313 if (!test_bit(FR_PRIVATE, &req->flags))
1314 list_del_init(&req->list);
1315 spin_unlock(&fpq->lock);
1316 request_end(fc, req);
1317 return err;
1318
1319 err_unlock:
1320 spin_unlock(&fiq->waitq.lock);
1321 return err;
1322 }
1323
1324 static int fuse_dev_open(struct inode *inode, struct file *file)
1325 {
1326 /*
1327 * The fuse device's file's private_data is used to hold
1328 * the fuse_conn(ection) when it is mounted, and is used to
1329 * keep track of whether the file has been mounted already.
1330 */
1331 file->private_data = NULL;
1332 return 0;
1333 }
1334
1335 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1336 {
1337 struct fuse_copy_state cs;
1338 struct file *file = iocb->ki_filp;
1339 struct fuse_dev *fud = fuse_get_dev(file);
1340
1341 if (!fud)
1342 return -EPERM;
1343
1344 if (!iter_is_iovec(to))
1345 return -EINVAL;
1346
1347 fuse_copy_init(&cs, 1, to);
1348
1349 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1350 }
1351
1352 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1353 struct pipe_inode_info *pipe,
1354 size_t len, unsigned int flags)
1355 {
1356 int total, ret;
1357 int page_nr = 0;
1358 struct pipe_buffer *bufs;
1359 struct fuse_copy_state cs;
1360 struct fuse_dev *fud = fuse_get_dev(in);
1361
1362 if (!fud)
1363 return -EPERM;
1364
1365 bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1366 GFP_KERNEL);
1367 if (!bufs)
1368 return -ENOMEM;
1369
1370 fuse_copy_init(&cs, 1, NULL);
1371 cs.pipebufs = bufs;
1372 cs.pipe = pipe;
1373 ret = fuse_dev_do_read(fud, in, &cs, len);
1374 if (ret < 0)
1375 goto out;
1376
1377 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1378 ret = -EIO;
1379 goto out;
1380 }
1381
1382 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1383 /*
1384 * Need to be careful about this. Having buf->ops in module
1385 * code can Oops if the buffer persists after module unload.
1386 */
1387 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1388 bufs[page_nr].flags = 0;
1389 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1390 if (unlikely(ret < 0))
1391 break;
1392 }
1393 if (total)
1394 ret = total;
1395 out:
1396 for (; page_nr < cs.nr_segs; page_nr++)
1397 put_page(bufs[page_nr].page);
1398
1399 kfree(bufs);
1400 return ret;
1401 }
1402
1403 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1404 struct fuse_copy_state *cs)
1405 {
1406 struct fuse_notify_poll_wakeup_out outarg;
1407 int err = -EINVAL;
1408
1409 if (size != sizeof(outarg))
1410 goto err;
1411
1412 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1413 if (err)
1414 goto err;
1415
1416 fuse_copy_finish(cs);
1417 return fuse_notify_poll_wakeup(fc, &outarg);
1418
1419 err:
1420 fuse_copy_finish(cs);
1421 return err;
1422 }
1423
1424 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1425 struct fuse_copy_state *cs)
1426 {
1427 struct fuse_notify_inval_inode_out outarg;
1428 int err = -EINVAL;
1429
1430 if (size != sizeof(outarg))
1431 goto err;
1432
1433 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1434 if (err)
1435 goto err;
1436 fuse_copy_finish(cs);
1437
1438 down_read(&fc->killsb);
1439 err = -ENOENT;
1440 if (fc->sb) {
1441 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1442 outarg.off, outarg.len);
1443 }
1444 up_read(&fc->killsb);
1445 return err;
1446
1447 err:
1448 fuse_copy_finish(cs);
1449 return err;
1450 }
1451
1452 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1453 struct fuse_copy_state *cs)
1454 {
1455 struct fuse_notify_inval_entry_out outarg;
1456 int err = -ENOMEM;
1457 char *buf;
1458 struct qstr name;
1459
1460 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1461 if (!buf)
1462 goto err;
1463
1464 err = -EINVAL;
1465 if (size < sizeof(outarg))
1466 goto err;
1467
1468 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1469 if (err)
1470 goto err;
1471
1472 err = -ENAMETOOLONG;
1473 if (outarg.namelen > FUSE_NAME_MAX)
1474 goto err;
1475
1476 err = -EINVAL;
1477 if (size != sizeof(outarg) + outarg.namelen + 1)
1478 goto err;
1479
1480 name.name = buf;
1481 name.len = outarg.namelen;
1482 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1483 if (err)
1484 goto err;
1485 fuse_copy_finish(cs);
1486 buf[outarg.namelen] = 0;
1487
1488 down_read(&fc->killsb);
1489 err = -ENOENT;
1490 if (fc->sb)
1491 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1492 up_read(&fc->killsb);
1493 kfree(buf);
1494 return err;
1495
1496 err:
1497 kfree(buf);
1498 fuse_copy_finish(cs);
1499 return err;
1500 }
1501
1502 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1503 struct fuse_copy_state *cs)
1504 {
1505 struct fuse_notify_delete_out outarg;
1506 int err = -ENOMEM;
1507 char *buf;
1508 struct qstr name;
1509
1510 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1511 if (!buf)
1512 goto err;
1513
1514 err = -EINVAL;
1515 if (size < sizeof(outarg))
1516 goto err;
1517
1518 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1519 if (err)
1520 goto err;
1521
1522 err = -ENAMETOOLONG;
1523 if (outarg.namelen > FUSE_NAME_MAX)
1524 goto err;
1525
1526 err = -EINVAL;
1527 if (size != sizeof(outarg) + outarg.namelen + 1)
1528 goto err;
1529
1530 name.name = buf;
1531 name.len = outarg.namelen;
1532 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1533 if (err)
1534 goto err;
1535 fuse_copy_finish(cs);
1536 buf[outarg.namelen] = 0;
1537
1538 down_read(&fc->killsb);
1539 err = -ENOENT;
1540 if (fc->sb)
1541 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1542 outarg.child, &name);
1543 up_read(&fc->killsb);
1544 kfree(buf);
1545 return err;
1546
1547 err:
1548 kfree(buf);
1549 fuse_copy_finish(cs);
1550 return err;
1551 }
1552
1553 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1554 struct fuse_copy_state *cs)
1555 {
1556 struct fuse_notify_store_out outarg;
1557 struct inode *inode;
1558 struct address_space *mapping;
1559 u64 nodeid;
1560 int err;
1561 pgoff_t index;
1562 unsigned int offset;
1563 unsigned int num;
1564 loff_t file_size;
1565 loff_t end;
1566
1567 err = -EINVAL;
1568 if (size < sizeof(outarg))
1569 goto out_finish;
1570
1571 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1572 if (err)
1573 goto out_finish;
1574
1575 err = -EINVAL;
1576 if (size - sizeof(outarg) != outarg.size)
1577 goto out_finish;
1578
1579 nodeid = outarg.nodeid;
1580
1581 down_read(&fc->killsb);
1582
1583 err = -ENOENT;
1584 if (!fc->sb)
1585 goto out_up_killsb;
1586
1587 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1588 if (!inode)
1589 goto out_up_killsb;
1590
1591 mapping = inode->i_mapping;
1592 index = outarg.offset >> PAGE_SHIFT;
1593 offset = outarg.offset & ~PAGE_MASK;
1594 file_size = i_size_read(inode);
1595 end = outarg.offset + outarg.size;
1596 if (end > file_size) {
1597 file_size = end;
1598 fuse_write_update_size(inode, file_size);
1599 }
1600
1601 num = outarg.size;
1602 while (num) {
1603 struct page *page;
1604 unsigned int this_num;
1605
1606 err = -ENOMEM;
1607 page = find_or_create_page(mapping, index,
1608 mapping_gfp_mask(mapping));
1609 if (!page)
1610 goto out_iput;
1611
1612 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1613 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1614 if (!err && offset == 0 &&
1615 (this_num == PAGE_SIZE || file_size == end))
1616 SetPageUptodate(page);
1617 unlock_page(page);
1618 put_page(page);
1619
1620 if (err)
1621 goto out_iput;
1622
1623 num -= this_num;
1624 offset = 0;
1625 index++;
1626 }
1627
1628 err = 0;
1629
1630 out_iput:
1631 iput(inode);
1632 out_up_killsb:
1633 up_read(&fc->killsb);
1634 out_finish:
1635 fuse_copy_finish(cs);
1636 return err;
1637 }
1638
1639 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1640 {
1641 release_pages(req->pages, req->num_pages);
1642 }
1643
1644 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1645 struct fuse_notify_retrieve_out *outarg)
1646 {
1647 int err;
1648 struct address_space *mapping = inode->i_mapping;
1649 struct fuse_req *req;
1650 pgoff_t index;
1651 loff_t file_size;
1652 unsigned int num;
1653 unsigned int offset;
1654 size_t total_len = 0;
1655 int num_pages;
1656
1657 offset = outarg->offset & ~PAGE_MASK;
1658 file_size = i_size_read(inode);
1659
1660 num = outarg->size;
1661 if (outarg->offset > file_size)
1662 num = 0;
1663 else if (outarg->offset + num > file_size)
1664 num = file_size - outarg->offset;
1665
1666 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1667 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1668
1669 req = fuse_get_req(fc, num_pages);
1670 if (IS_ERR(req))
1671 return PTR_ERR(req);
1672
1673 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1674 req->in.h.nodeid = outarg->nodeid;
1675 req->in.numargs = 2;
1676 req->in.argpages = 1;
1677 req->page_descs[0].offset = offset;
1678 req->end = fuse_retrieve_end;
1679
1680 index = outarg->offset >> PAGE_SHIFT;
1681
1682 while (num && req->num_pages < num_pages) {
1683 struct page *page;
1684 unsigned int this_num;
1685
1686 page = find_get_page(mapping, index);
1687 if (!page)
1688 break;
1689
1690 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1691 req->pages[req->num_pages] = page;
1692 req->page_descs[req->num_pages].length = this_num;
1693 req->num_pages++;
1694
1695 offset = 0;
1696 num -= this_num;
1697 total_len += this_num;
1698 index++;
1699 }
1700 req->misc.retrieve_in.offset = outarg->offset;
1701 req->misc.retrieve_in.size = total_len;
1702 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1703 req->in.args[0].value = &req->misc.retrieve_in;
1704 req->in.args[1].size = total_len;
1705
1706 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1707 if (err)
1708 fuse_retrieve_end(fc, req);
1709
1710 return err;
1711 }
1712
1713 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1714 struct fuse_copy_state *cs)
1715 {
1716 struct fuse_notify_retrieve_out outarg;
1717 struct inode *inode;
1718 int err;
1719
1720 err = -EINVAL;
1721 if (size != sizeof(outarg))
1722 goto copy_finish;
1723
1724 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1725 if (err)
1726 goto copy_finish;
1727
1728 fuse_copy_finish(cs);
1729
1730 down_read(&fc->killsb);
1731 err = -ENOENT;
1732 if (fc->sb) {
1733 u64 nodeid = outarg.nodeid;
1734
1735 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1736 if (inode) {
1737 err = fuse_retrieve(fc, inode, &outarg);
1738 iput(inode);
1739 }
1740 }
1741 up_read(&fc->killsb);
1742
1743 return err;
1744
1745 copy_finish:
1746 fuse_copy_finish(cs);
1747 return err;
1748 }
1749
1750 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1751 unsigned int size, struct fuse_copy_state *cs)
1752 {
1753 /* Don't try to move pages (yet) */
1754 cs->move_pages = 0;
1755
1756 switch (code) {
1757 case FUSE_NOTIFY_POLL:
1758 return fuse_notify_poll(fc, size, cs);
1759
1760 case FUSE_NOTIFY_INVAL_INODE:
1761 return fuse_notify_inval_inode(fc, size, cs);
1762
1763 case FUSE_NOTIFY_INVAL_ENTRY:
1764 return fuse_notify_inval_entry(fc, size, cs);
1765
1766 case FUSE_NOTIFY_STORE:
1767 return fuse_notify_store(fc, size, cs);
1768
1769 case FUSE_NOTIFY_RETRIEVE:
1770 return fuse_notify_retrieve(fc, size, cs);
1771
1772 case FUSE_NOTIFY_DELETE:
1773 return fuse_notify_delete(fc, size, cs);
1774
1775 default:
1776 fuse_copy_finish(cs);
1777 return -EINVAL;
1778 }
1779 }
1780
1781 /* Look up request on processing list by unique ID */
1782 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1783 {
1784 struct fuse_req *req;
1785
1786 list_for_each_entry(req, &fpq->processing, list) {
1787 if (req->in.h.unique == unique || req->intr_unique == unique)
1788 return req;
1789 }
1790 return NULL;
1791 }
1792
1793 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1794 unsigned nbytes)
1795 {
1796 unsigned reqsize = sizeof(struct fuse_out_header);
1797
1798 if (out->h.error)
1799 return nbytes != reqsize ? -EINVAL : 0;
1800
1801 reqsize += len_args(out->numargs, out->args);
1802
1803 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1804 return -EINVAL;
1805 else if (reqsize > nbytes) {
1806 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1807 unsigned diffsize = reqsize - nbytes;
1808 if (diffsize > lastarg->size)
1809 return -EINVAL;
1810 lastarg->size -= diffsize;
1811 }
1812 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1813 out->page_zeroing);
1814 }
1815
1816 /*
1817 * Write a single reply to a request. First the header is copied from
1818 * the write buffer. The request is then searched on the processing
1819 * list by the unique ID found in the header. If found, then remove
1820 * it from the list and copy the rest of the buffer to the request.
1821 * The request is finished by calling request_end()
1822 */
1823 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1824 struct fuse_copy_state *cs, size_t nbytes)
1825 {
1826 int err;
1827 struct fuse_conn *fc = fud->fc;
1828 struct fuse_pqueue *fpq = &fud->pq;
1829 struct fuse_req *req;
1830 struct fuse_out_header oh;
1831
1832 if (nbytes < sizeof(struct fuse_out_header))
1833 return -EINVAL;
1834
1835 err = fuse_copy_one(cs, &oh, sizeof(oh));
1836 if (err)
1837 goto err_finish;
1838
1839 err = -EINVAL;
1840 if (oh.len != nbytes)
1841 goto err_finish;
1842
1843 /*
1844 * Zero oh.unique indicates unsolicited notification message
1845 * and error contains notification code.
1846 */
1847 if (!oh.unique) {
1848 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1849 return err ? err : nbytes;
1850 }
1851
1852 err = -EINVAL;
1853 if (oh.error <= -1000 || oh.error > 0)
1854 goto err_finish;
1855
1856 spin_lock(&fpq->lock);
1857 err = -ENOENT;
1858 if (!fpq->connected)
1859 goto err_unlock_pq;
1860
1861 req = request_find(fpq, oh.unique);
1862 if (!req)
1863 goto err_unlock_pq;
1864
1865 /* Is it an interrupt reply? */
1866 if (req->intr_unique == oh.unique) {
1867 spin_unlock(&fpq->lock);
1868
1869 err = -EINVAL;
1870 if (nbytes != sizeof(struct fuse_out_header))
1871 goto err_finish;
1872
1873 if (oh.error == -ENOSYS)
1874 fc->no_interrupt = 1;
1875 else if (oh.error == -EAGAIN)
1876 queue_interrupt(&fc->iq, req);
1877
1878 fuse_copy_finish(cs);
1879 return nbytes;
1880 }
1881
1882 clear_bit(FR_SENT, &req->flags);
1883 list_move(&req->list, &fpq->io);
1884 req->out.h = oh;
1885 set_bit(FR_LOCKED, &req->flags);
1886 spin_unlock(&fpq->lock);
1887 cs->req = req;
1888 if (!req->out.page_replace)
1889 cs->move_pages = 0;
1890
1891 err = copy_out_args(cs, &req->out, nbytes);
1892 fuse_copy_finish(cs);
1893
1894 spin_lock(&fpq->lock);
1895 clear_bit(FR_LOCKED, &req->flags);
1896 if (!fpq->connected)
1897 err = -ENOENT;
1898 else if (err)
1899 req->out.h.error = -EIO;
1900 if (!test_bit(FR_PRIVATE, &req->flags))
1901 list_del_init(&req->list);
1902 spin_unlock(&fpq->lock);
1903
1904 request_end(fc, req);
1905
1906 return err ? err : nbytes;
1907
1908 err_unlock_pq:
1909 spin_unlock(&fpq->lock);
1910 err_finish:
1911 fuse_copy_finish(cs);
1912 return err;
1913 }
1914
1915 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1916 {
1917 struct fuse_copy_state cs;
1918 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1919
1920 if (!fud)
1921 return -EPERM;
1922
1923 if (!iter_is_iovec(from))
1924 return -EINVAL;
1925
1926 fuse_copy_init(&cs, 0, from);
1927
1928 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1929 }
1930
1931 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1932 struct file *out, loff_t *ppos,
1933 size_t len, unsigned int flags)
1934 {
1935 unsigned nbuf;
1936 unsigned idx;
1937 struct pipe_buffer *bufs;
1938 struct fuse_copy_state cs;
1939 struct fuse_dev *fud;
1940 size_t rem;
1941 ssize_t ret;
1942
1943 fud = fuse_get_dev(out);
1944 if (!fud)
1945 return -EPERM;
1946
1947 bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1948 GFP_KERNEL);
1949 if (!bufs)
1950 return -ENOMEM;
1951
1952 pipe_lock(pipe);
1953 nbuf = 0;
1954 rem = 0;
1955 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1956 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1957
1958 ret = -EINVAL;
1959 if (rem < len) {
1960 pipe_unlock(pipe);
1961 goto out;
1962 }
1963
1964 rem = len;
1965 while (rem) {
1966 struct pipe_buffer *ibuf;
1967 struct pipe_buffer *obuf;
1968
1969 BUG_ON(nbuf >= pipe->buffers);
1970 BUG_ON(!pipe->nrbufs);
1971 ibuf = &pipe->bufs[pipe->curbuf];
1972 obuf = &bufs[nbuf];
1973
1974 if (rem >= ibuf->len) {
1975 *obuf = *ibuf;
1976 ibuf->ops = NULL;
1977 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1978 pipe->nrbufs--;
1979 } else {
1980 pipe_buf_get(pipe, ibuf);
1981 *obuf = *ibuf;
1982 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1983 obuf->len = rem;
1984 ibuf->offset += obuf->len;
1985 ibuf->len -= obuf->len;
1986 }
1987 nbuf++;
1988 rem -= obuf->len;
1989 }
1990 pipe_unlock(pipe);
1991
1992 fuse_copy_init(&cs, 0, NULL);
1993 cs.pipebufs = bufs;
1994 cs.nr_segs = nbuf;
1995 cs.pipe = pipe;
1996
1997 if (flags & SPLICE_F_MOVE)
1998 cs.move_pages = 1;
1999
2000 ret = fuse_dev_do_write(fud, &cs, len);
2001
2002 for (idx = 0; idx < nbuf; idx++)
2003 pipe_buf_release(pipe, &bufs[idx]);
2004
2005 out:
2006 kfree(bufs);
2007 return ret;
2008 }
2009
2010 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2011 {
2012 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2013 struct fuse_iqueue *fiq;
2014 struct fuse_dev *fud = fuse_get_dev(file);
2015
2016 if (!fud)
2017 return EPOLLERR;
2018
2019 fiq = &fud->fc->iq;
2020 poll_wait(file, &fiq->waitq, wait);
2021
2022 spin_lock(&fiq->waitq.lock);
2023 if (!fiq->connected)
2024 mask = EPOLLERR;
2025 else if (request_pending(fiq))
2026 mask |= EPOLLIN | EPOLLRDNORM;
2027 spin_unlock(&fiq->waitq.lock);
2028
2029 return mask;
2030 }
2031
2032 /*
2033 * Abort all requests on the given list (pending or processing)
2034 *
2035 * This function releases and reacquires fc->lock
2036 */
2037 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2038 {
2039 while (!list_empty(head)) {
2040 struct fuse_req *req;
2041 req = list_entry(head->next, struct fuse_req, list);
2042 req->out.h.error = -ECONNABORTED;
2043 clear_bit(FR_SENT, &req->flags);
2044 list_del_init(&req->list);
2045 request_end(fc, req);
2046 }
2047 }
2048
2049 static void end_polls(struct fuse_conn *fc)
2050 {
2051 struct rb_node *p;
2052
2053 p = rb_first(&fc->polled_files);
2054
2055 while (p) {
2056 struct fuse_file *ff;
2057 ff = rb_entry(p, struct fuse_file, polled_node);
2058 wake_up_interruptible_all(&ff->poll_wait);
2059
2060 p = rb_next(p);
2061 }
2062 }
2063
2064 /*
2065 * Abort all requests.
2066 *
2067 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2068 * filesystem.
2069 *
2070 * The same effect is usually achievable through killing the filesystem daemon
2071 * and all users of the filesystem. The exception is the combination of an
2072 * asynchronous request and the tricky deadlock (see
2073 * Documentation/filesystems/fuse.txt).
2074 *
2075 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2076 * requests, they should be finished off immediately. Locked requests will be
2077 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2078 * requests. It is possible that some request will finish before we can. This
2079 * is OK, the request will in that case be removed from the list before we touch
2080 * it.
2081 */
2082 void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
2083 {
2084 struct fuse_iqueue *fiq = &fc->iq;
2085
2086 spin_lock(&fc->lock);
2087 if (fc->connected) {
2088 struct fuse_dev *fud;
2089 struct fuse_req *req, *next;
2090 LIST_HEAD(to_end1);
2091 LIST_HEAD(to_end2);
2092
2093 fc->connected = 0;
2094 fc->blocked = 0;
2095 fc->aborted = is_abort;
2096 fuse_set_initialized(fc);
2097 list_for_each_entry(fud, &fc->devices, entry) {
2098 struct fuse_pqueue *fpq = &fud->pq;
2099
2100 spin_lock(&fpq->lock);
2101 fpq->connected = 0;
2102 list_for_each_entry_safe(req, next, &fpq->io, list) {
2103 req->out.h.error = -ECONNABORTED;
2104 spin_lock(&req->waitq.lock);
2105 set_bit(FR_ABORTED, &req->flags);
2106 if (!test_bit(FR_LOCKED, &req->flags)) {
2107 set_bit(FR_PRIVATE, &req->flags);
2108 list_move(&req->list, &to_end1);
2109 }
2110 spin_unlock(&req->waitq.lock);
2111 }
2112 list_splice_init(&fpq->processing, &to_end2);
2113 spin_unlock(&fpq->lock);
2114 }
2115 fc->max_background = UINT_MAX;
2116 flush_bg_queue(fc);
2117
2118 spin_lock(&fiq->waitq.lock);
2119 fiq->connected = 0;
2120 list_splice_init(&fiq->pending, &to_end2);
2121 list_for_each_entry(req, &to_end2, list)
2122 clear_bit(FR_PENDING, &req->flags);
2123 while (forget_pending(fiq))
2124 kfree(dequeue_forget(fiq, 1, NULL));
2125 wake_up_all_locked(&fiq->waitq);
2126 spin_unlock(&fiq->waitq.lock);
2127 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2128 end_polls(fc);
2129 wake_up_all(&fc->blocked_waitq);
2130 spin_unlock(&fc->lock);
2131
2132 while (!list_empty(&to_end1)) {
2133 req = list_first_entry(&to_end1, struct fuse_req, list);
2134 __fuse_get_request(req);
2135 list_del_init(&req->list);
2136 request_end(fc, req);
2137 }
2138 end_requests(fc, &to_end2);
2139 } else {
2140 spin_unlock(&fc->lock);
2141 }
2142 }
2143 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2144
2145 int fuse_dev_release(struct inode *inode, struct file *file)
2146 {
2147 struct fuse_dev *fud = fuse_get_dev(file);
2148
2149 if (fud) {
2150 struct fuse_conn *fc = fud->fc;
2151 struct fuse_pqueue *fpq = &fud->pq;
2152
2153 WARN_ON(!list_empty(&fpq->io));
2154 end_requests(fc, &fpq->processing);
2155 /* Are we the last open device? */
2156 if (atomic_dec_and_test(&fc->dev_count)) {
2157 WARN_ON(fc->iq.fasync != NULL);
2158 fuse_abort_conn(fc, false);
2159 }
2160 fuse_dev_free(fud);
2161 }
2162 return 0;
2163 }
2164 EXPORT_SYMBOL_GPL(fuse_dev_release);
2165
2166 static int fuse_dev_fasync(int fd, struct file *file, int on)
2167 {
2168 struct fuse_dev *fud = fuse_get_dev(file);
2169
2170 if (!fud)
2171 return -EPERM;
2172
2173 /* No locking - fasync_helper does its own locking */
2174 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2175 }
2176
2177 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2178 {
2179 struct fuse_dev *fud;
2180
2181 if (new->private_data)
2182 return -EINVAL;
2183
2184 fud = fuse_dev_alloc(fc);
2185 if (!fud)
2186 return -ENOMEM;
2187
2188 new->private_data = fud;
2189 atomic_inc(&fc->dev_count);
2190
2191 return 0;
2192 }
2193
2194 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2195 unsigned long arg)
2196 {
2197 int err = -ENOTTY;
2198
2199 if (cmd == FUSE_DEV_IOC_CLONE) {
2200 int oldfd;
2201
2202 err = -EFAULT;
2203 if (!get_user(oldfd, (__u32 __user *) arg)) {
2204 struct file *old = fget(oldfd);
2205
2206 err = -EINVAL;
2207 if (old) {
2208 struct fuse_dev *fud = NULL;
2209
2210 /*
2211 * Check against file->f_op because CUSE
2212 * uses the same ioctl handler.
2213 */
2214 if (old->f_op == file->f_op &&
2215 old->f_cred->user_ns == file->f_cred->user_ns)
2216 fud = fuse_get_dev(old);
2217
2218 if (fud) {
2219 mutex_lock(&fuse_mutex);
2220 err = fuse_device_clone(fud->fc, file);
2221 mutex_unlock(&fuse_mutex);
2222 }
2223 fput(old);
2224 }
2225 }
2226 }
2227 return err;
2228 }
2229
2230 const struct file_operations fuse_dev_operations = {
2231 .owner = THIS_MODULE,
2232 .open = fuse_dev_open,
2233 .llseek = no_llseek,
2234 .read_iter = fuse_dev_read,
2235 .splice_read = fuse_dev_splice_read,
2236 .write_iter = fuse_dev_write,
2237 .splice_write = fuse_dev_splice_write,
2238 .poll = fuse_dev_poll,
2239 .release = fuse_dev_release,
2240 .fasync = fuse_dev_fasync,
2241 .unlocked_ioctl = fuse_dev_ioctl,
2242 .compat_ioctl = fuse_dev_ioctl,
2243 };
2244 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2245
2246 static struct miscdevice fuse_miscdevice = {
2247 .minor = FUSE_MINOR,
2248 .name = "fuse",
2249 .fops = &fuse_dev_operations,
2250 };
2251
2252 int __init fuse_dev_init(void)
2253 {
2254 int err = -ENOMEM;
2255 fuse_req_cachep = kmem_cache_create("fuse_request",
2256 sizeof(struct fuse_req),
2257 0, 0, NULL);
2258 if (!fuse_req_cachep)
2259 goto out;
2260
2261 err = misc_register(&fuse_miscdevice);
2262 if (err)
2263 goto out_cache_clean;
2264
2265 return 0;
2266
2267 out_cache_clean:
2268 kmem_cache_destroy(fuse_req_cachep);
2269 out:
2270 return err;
2271 }
2272
2273 void fuse_dev_cleanup(void)
2274 {
2275 misc_deregister(&fuse_miscdevice);
2276 kmem_cache_destroy(fuse_req_cachep);
2277 }
Linux with added FPC-III support