projects/linux·blob v4.2 · refs

2318 lines · 52.1 KiB

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