Merge tag 'fuse-update-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mszered...
[sfrench/cifs-2.6.git] / fs / fuse / dev.c
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
4
5   This program can be distributed under the terms of the GNU GPL.
6   See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/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(sizeof(struct page *) * npages, flags);
68                         page_descs = kmalloc(sizeof(struct fuse_page_desc) *
69                                              npages, flags);
70                 }
71
72                 if (!pages || !page_descs) {
73                         kfree(pages);
74                         kfree(page_descs);
75                         kmem_cache_free(fuse_req_cachep, req);
76                         return NULL;
77                 }
78
79                 fuse_request_init(req, pages, page_descs, npages);
80         }
81         return req;
82 }
83
84 struct fuse_req *fuse_request_alloc(unsigned npages)
85 {
86         return __fuse_request_alloc(npages, GFP_KERNEL);
87 }
88 EXPORT_SYMBOL_GPL(fuse_request_alloc);
89
90 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
91 {
92         return __fuse_request_alloc(npages, GFP_NOFS);
93 }
94
95 void fuse_request_free(struct fuse_req *req)
96 {
97         if (req->pages != req->inline_pages) {
98                 kfree(req->pages);
99                 kfree(req->page_descs);
100         }
101         kmem_cache_free(fuse_req_cachep, req);
102 }
103
104 void __fuse_get_request(struct fuse_req *req)
105 {
106         refcount_inc(&req->count);
107 }
108
109 /* Must be called with > 1 refcount */
110 static void __fuse_put_request(struct fuse_req *req)
111 {
112         refcount_dec(&req->count);
113 }
114
115 void fuse_set_initialized(struct fuse_conn *fc)
116 {
117         /* Make sure stores before this are seen on another CPU */
118         smp_wmb();
119         fc->initialized = 1;
120 }
121
122 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
123 {
124         return !fc->initialized || (for_background && fc->blocked);
125 }
126
127 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
128                                        bool for_background)
129 {
130         struct fuse_req *req;
131         int err;
132         atomic_inc(&fc->num_waiting);
133
134         if (fuse_block_alloc(fc, for_background)) {
135                 err = -EINTR;
136                 if (wait_event_killable_exclusive(fc->blocked_waitq,
137                                 !fuse_block_alloc(fc, for_background)))
138                         goto out;
139         }
140         /* Matches smp_wmb() in fuse_set_initialized() */
141         smp_rmb();
142
143         err = -ENOTCONN;
144         if (!fc->connected)
145                 goto out;
146
147         err = -ECONNREFUSED;
148         if (fc->conn_error)
149                 goto out;
150
151         req = fuse_request_alloc(npages);
152         err = -ENOMEM;
153         if (!req) {
154                 if (for_background)
155                         wake_up(&fc->blocked_waitq);
156                 goto out;
157         }
158
159         req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
160         req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
161         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
162
163         __set_bit(FR_WAITING, &req->flags);
164         if (for_background)
165                 __set_bit(FR_BACKGROUND, &req->flags);
166
167         if (unlikely(req->in.h.uid == ((uid_t)-1) ||
168                      req->in.h.gid == ((gid_t)-1))) {
169                 fuse_put_request(fc, req);
170                 return ERR_PTR(-EOVERFLOW);
171         }
172         return req;
173
174  out:
175         atomic_dec(&fc->num_waiting);
176         return ERR_PTR(err);
177 }
178
179 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
180 {
181         return __fuse_get_req(fc, npages, false);
182 }
183 EXPORT_SYMBOL_GPL(fuse_get_req);
184
185 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
186                                              unsigned npages)
187 {
188         return __fuse_get_req(fc, npages, true);
189 }
190 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
191
192 /*
193  * Return request in fuse_file->reserved_req.  However that may
194  * currently be in use.  If that is the case, wait for it to become
195  * available.
196  */
197 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
198                                          struct file *file)
199 {
200         struct fuse_req *req = NULL;
201         struct fuse_file *ff = file->private_data;
202
203         do {
204                 wait_event(fc->reserved_req_waitq, ff->reserved_req);
205                 spin_lock(&fc->lock);
206                 if (ff->reserved_req) {
207                         req = ff->reserved_req;
208                         ff->reserved_req = NULL;
209                         req->stolen_file = get_file(file);
210                 }
211                 spin_unlock(&fc->lock);
212         } while (!req);
213
214         return req;
215 }
216
217 /*
218  * Put stolen request back into fuse_file->reserved_req
219  */
220 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
221 {
222         struct file *file = req->stolen_file;
223         struct fuse_file *ff = file->private_data;
224
225         spin_lock(&fc->lock);
226         fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
227         BUG_ON(ff->reserved_req);
228         ff->reserved_req = req;
229         wake_up_all(&fc->reserved_req_waitq);
230         spin_unlock(&fc->lock);
231         fput(file);
232 }
233
234 /*
235  * Gets a requests for a file operation, always succeeds
236  *
237  * This is used for sending the FLUSH request, which must get to
238  * userspace, due to POSIX locks which may need to be unlocked.
239  *
240  * If allocation fails due to OOM, use the reserved request in
241  * fuse_file.
242  *
243  * This is very unlikely to deadlock accidentally, since the
244  * filesystem should not have it's own file open.  If deadlock is
245  * intentional, it can still be broken by "aborting" the filesystem.
246  */
247 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
248                                              struct file *file)
249 {
250         struct fuse_req *req;
251
252         atomic_inc(&fc->num_waiting);
253         wait_event(fc->blocked_waitq, fc->initialized);
254         /* Matches smp_wmb() in fuse_set_initialized() */
255         smp_rmb();
256         req = fuse_request_alloc(0);
257         if (!req)
258                 req = get_reserved_req(fc, file);
259
260         req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
261         req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
262         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
263
264         __set_bit(FR_WAITING, &req->flags);
265         __clear_bit(FR_BACKGROUND, &req->flags);
266         return req;
267 }
268
269 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
270 {
271         if (refcount_dec_and_test(&req->count)) {
272                 if (test_bit(FR_BACKGROUND, &req->flags)) {
273                         /*
274                          * We get here in the unlikely case that a background
275                          * request was allocated but not sent
276                          */
277                         spin_lock(&fc->lock);
278                         if (!fc->blocked)
279                                 wake_up(&fc->blocked_waitq);
280                         spin_unlock(&fc->lock);
281                 }
282
283                 if (test_bit(FR_WAITING, &req->flags)) {
284                         __clear_bit(FR_WAITING, &req->flags);
285                         atomic_dec(&fc->num_waiting);
286                 }
287
288                 if (req->stolen_file)
289                         put_reserved_req(fc, req);
290                 else
291                         fuse_request_free(req);
292         }
293 }
294 EXPORT_SYMBOL_GPL(fuse_put_request);
295
296 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
297 {
298         unsigned nbytes = 0;
299         unsigned i;
300
301         for (i = 0; i < numargs; i++)
302                 nbytes += args[i].size;
303
304         return nbytes;
305 }
306
307 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
308 {
309         return ++fiq->reqctr;
310 }
311
312 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
313 {
314         req->in.h.len = sizeof(struct fuse_in_header) +
315                 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
316         list_add_tail(&req->list, &fiq->pending);
317         wake_up_locked(&fiq->waitq);
318         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
319 }
320
321 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
322                        u64 nodeid, u64 nlookup)
323 {
324         struct fuse_iqueue *fiq = &fc->iq;
325
326         forget->forget_one.nodeid = nodeid;
327         forget->forget_one.nlookup = nlookup;
328
329         spin_lock(&fiq->waitq.lock);
330         if (fiq->connected) {
331                 fiq->forget_list_tail->next = forget;
332                 fiq->forget_list_tail = forget;
333                 wake_up_locked(&fiq->waitq);
334                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
335         } else {
336                 kfree(forget);
337         }
338         spin_unlock(&fiq->waitq.lock);
339 }
340
341 static void flush_bg_queue(struct fuse_conn *fc)
342 {
343         while (fc->active_background < fc->max_background &&
344                !list_empty(&fc->bg_queue)) {
345                 struct fuse_req *req;
346                 struct fuse_iqueue *fiq = &fc->iq;
347
348                 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
349                 list_del(&req->list);
350                 fc->active_background++;
351                 spin_lock(&fiq->waitq.lock);
352                 req->in.h.unique = fuse_get_unique(fiq);
353                 queue_request(fiq, req);
354                 spin_unlock(&fiq->waitq.lock);
355         }
356 }
357
358 /*
359  * This function is called when a request is finished.  Either a reply
360  * has arrived or it was aborted (and not yet sent) or some error
361  * occurred during communication with userspace, or the device file
362  * was closed.  The requester thread is woken up (if still waiting),
363  * the 'end' callback is called if given, else the reference to the
364  * request is released
365  */
366 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
367 {
368         struct fuse_iqueue *fiq = &fc->iq;
369
370         if (test_and_set_bit(FR_FINISHED, &req->flags))
371                 return;
372
373         spin_lock(&fiq->waitq.lock);
374         list_del_init(&req->intr_entry);
375         spin_unlock(&fiq->waitq.lock);
376         WARN_ON(test_bit(FR_PENDING, &req->flags));
377         WARN_ON(test_bit(FR_SENT, &req->flags));
378         if (test_bit(FR_BACKGROUND, &req->flags)) {
379                 spin_lock(&fc->lock);
380                 clear_bit(FR_BACKGROUND, &req->flags);
381                 if (fc->num_background == fc->max_background)
382                         fc->blocked = 0;
383
384                 /* Wake up next waiter, if any */
385                 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
386                         wake_up(&fc->blocked_waitq);
387
388                 if (fc->num_background == fc->congestion_threshold && fc->sb) {
389                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
390                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
391                 }
392                 fc->num_background--;
393                 fc->active_background--;
394                 flush_bg_queue(fc);
395                 spin_unlock(&fc->lock);
396         }
397         wake_up(&req->waitq);
398         if (req->end)
399                 req->end(fc, req);
400         fuse_put_request(fc, req);
401 }
402
403 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
404 {
405         spin_lock(&fiq->waitq.lock);
406         if (test_bit(FR_FINISHED, &req->flags)) {
407                 spin_unlock(&fiq->waitq.lock);
408                 return;
409         }
410         if (list_empty(&req->intr_entry)) {
411                 list_add_tail(&req->intr_entry, &fiq->interrupts);
412                 wake_up_locked(&fiq->waitq);
413         }
414         spin_unlock(&fiq->waitq.lock);
415         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
416 }
417
418 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
419 {
420         struct fuse_iqueue *fiq = &fc->iq;
421         int err;
422
423         if (!fc->no_interrupt) {
424                 /* Any signal may interrupt this */
425                 err = wait_event_interruptible(req->waitq,
426                                         test_bit(FR_FINISHED, &req->flags));
427                 if (!err)
428                         return;
429
430                 set_bit(FR_INTERRUPTED, &req->flags);
431                 /* matches barrier in fuse_dev_do_read() */
432                 smp_mb__after_atomic();
433                 if (test_bit(FR_SENT, &req->flags))
434                         queue_interrupt(fiq, req);
435         }
436
437         if (!test_bit(FR_FORCE, &req->flags)) {
438                 /* Only fatal signals may interrupt this */
439                 err = wait_event_killable(req->waitq,
440                                         test_bit(FR_FINISHED, &req->flags));
441                 if (!err)
442                         return;
443
444                 spin_lock(&fiq->waitq.lock);
445                 /* Request is not yet in userspace, bail out */
446                 if (test_bit(FR_PENDING, &req->flags)) {
447                         list_del(&req->list);
448                         spin_unlock(&fiq->waitq.lock);
449                         __fuse_put_request(req);
450                         req->out.h.error = -EINTR;
451                         return;
452                 }
453                 spin_unlock(&fiq->waitq.lock);
454         }
455
456         /*
457          * Either request is already in userspace, or it was forced.
458          * Wait it out.
459          */
460         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
461 }
462
463 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
464 {
465         struct fuse_iqueue *fiq = &fc->iq;
466
467         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
468         spin_lock(&fiq->waitq.lock);
469         if (!fiq->connected) {
470                 spin_unlock(&fiq->waitq.lock);
471                 req->out.h.error = -ENOTCONN;
472         } else {
473                 req->in.h.unique = fuse_get_unique(fiq);
474                 queue_request(fiq, req);
475                 /* acquire extra reference, since request is still needed
476                    after request_end() */
477                 __fuse_get_request(req);
478                 spin_unlock(&fiq->waitq.lock);
479
480                 request_wait_answer(fc, req);
481                 /* Pairs with smp_wmb() in request_end() */
482                 smp_rmb();
483         }
484 }
485
486 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
487 {
488         __set_bit(FR_ISREPLY, &req->flags);
489         if (!test_bit(FR_WAITING, &req->flags)) {
490                 __set_bit(FR_WAITING, &req->flags);
491                 atomic_inc(&fc->num_waiting);
492         }
493         __fuse_request_send(fc, req);
494 }
495 EXPORT_SYMBOL_GPL(fuse_request_send);
496
497 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
498 {
499         if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
500                 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
501
502         if (fc->minor < 9) {
503                 switch (args->in.h.opcode) {
504                 case FUSE_LOOKUP:
505                 case FUSE_CREATE:
506                 case FUSE_MKNOD:
507                 case FUSE_MKDIR:
508                 case FUSE_SYMLINK:
509                 case FUSE_LINK:
510                         args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
511                         break;
512                 case FUSE_GETATTR:
513                 case FUSE_SETATTR:
514                         args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
515                         break;
516                 }
517         }
518         if (fc->minor < 12) {
519                 switch (args->in.h.opcode) {
520                 case FUSE_CREATE:
521                         args->in.args[0].size = sizeof(struct fuse_open_in);
522                         break;
523                 case FUSE_MKNOD:
524                         args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
525                         break;
526                 }
527         }
528 }
529
530 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
531 {
532         struct fuse_req *req;
533         ssize_t ret;
534
535         req = fuse_get_req(fc, 0);
536         if (IS_ERR(req))
537                 return PTR_ERR(req);
538
539         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
540         fuse_adjust_compat(fc, args);
541
542         req->in.h.opcode = args->in.h.opcode;
543         req->in.h.nodeid = args->in.h.nodeid;
544         req->in.numargs = args->in.numargs;
545         memcpy(req->in.args, args->in.args,
546                args->in.numargs * sizeof(struct fuse_in_arg));
547         req->out.argvar = args->out.argvar;
548         req->out.numargs = args->out.numargs;
549         memcpy(req->out.args, args->out.args,
550                args->out.numargs * sizeof(struct fuse_arg));
551         fuse_request_send(fc, req);
552         ret = req->out.h.error;
553         if (!ret && args->out.argvar) {
554                 BUG_ON(args->out.numargs != 1);
555                 ret = req->out.args[0].size;
556         }
557         fuse_put_request(fc, req);
558
559         return ret;
560 }
561
562 /*
563  * Called under fc->lock
564  *
565  * fc->connected must have been checked previously
566  */
567 void fuse_request_send_background_locked(struct fuse_conn *fc,
568                                          struct fuse_req *req)
569 {
570         BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
571         if (!test_bit(FR_WAITING, &req->flags)) {
572                 __set_bit(FR_WAITING, &req->flags);
573                 atomic_inc(&fc->num_waiting);
574         }
575         __set_bit(FR_ISREPLY, &req->flags);
576         fc->num_background++;
577         if (fc->num_background == fc->max_background)
578                 fc->blocked = 1;
579         if (fc->num_background == fc->congestion_threshold && fc->sb) {
580                 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
581                 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
582         }
583         list_add_tail(&req->list, &fc->bg_queue);
584         flush_bg_queue(fc);
585 }
586
587 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
588 {
589         BUG_ON(!req->end);
590         spin_lock(&fc->lock);
591         if (fc->connected) {
592                 fuse_request_send_background_locked(fc, req);
593                 spin_unlock(&fc->lock);
594         } else {
595                 spin_unlock(&fc->lock);
596                 req->out.h.error = -ENOTCONN;
597                 req->end(fc, req);
598                 fuse_put_request(fc, req);
599         }
600 }
601 EXPORT_SYMBOL_GPL(fuse_request_send_background);
602
603 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
604                                           struct fuse_req *req, u64 unique)
605 {
606         int err = -ENODEV;
607         struct fuse_iqueue *fiq = &fc->iq;
608
609         __clear_bit(FR_ISREPLY, &req->flags);
610         req->in.h.unique = unique;
611         spin_lock(&fiq->waitq.lock);
612         if (fiq->connected) {
613                 queue_request(fiq, req);
614                 err = 0;
615         }
616         spin_unlock(&fiq->waitq.lock);
617
618         return err;
619 }
620
621 void fuse_force_forget(struct file *file, u64 nodeid)
622 {
623         struct inode *inode = file_inode(file);
624         struct fuse_conn *fc = get_fuse_conn(inode);
625         struct fuse_req *req;
626         struct fuse_forget_in inarg;
627
628         memset(&inarg, 0, sizeof(inarg));
629         inarg.nlookup = 1;
630         req = fuse_get_req_nofail_nopages(fc, file);
631         req->in.h.opcode = FUSE_FORGET;
632         req->in.h.nodeid = nodeid;
633         req->in.numargs = 1;
634         req->in.args[0].size = sizeof(inarg);
635         req->in.args[0].value = &inarg;
636         __clear_bit(FR_ISREPLY, &req->flags);
637         __fuse_request_send(fc, req);
638         /* ignore errors */
639         fuse_put_request(fc, req);
640 }
641
642 /*
643  * Lock the request.  Up to the next unlock_request() there mustn't be
644  * anything that could cause a page-fault.  If the request was already
645  * aborted bail out.
646  */
647 static int lock_request(struct fuse_req *req)
648 {
649         int err = 0;
650         if (req) {
651                 spin_lock(&req->waitq.lock);
652                 if (test_bit(FR_ABORTED, &req->flags))
653                         err = -ENOENT;
654                 else
655                         set_bit(FR_LOCKED, &req->flags);
656                 spin_unlock(&req->waitq.lock);
657         }
658         return err;
659 }
660
661 /*
662  * Unlock request.  If it was aborted while locked, caller is responsible
663  * for unlocking and ending the request.
664  */
665 static int unlock_request(struct fuse_req *req)
666 {
667         int err = 0;
668         if (req) {
669                 spin_lock(&req->waitq.lock);
670                 if (test_bit(FR_ABORTED, &req->flags))
671                         err = -ENOENT;
672                 else
673                         clear_bit(FR_LOCKED, &req->flags);
674                 spin_unlock(&req->waitq.lock);
675         }
676         return err;
677 }
678
679 struct fuse_copy_state {
680         int write;
681         struct fuse_req *req;
682         struct iov_iter *iter;
683         struct pipe_buffer *pipebufs;
684         struct pipe_buffer *currbuf;
685         struct pipe_inode_info *pipe;
686         unsigned long nr_segs;
687         struct page *pg;
688         unsigned len;
689         unsigned offset;
690         unsigned move_pages:1;
691 };
692
693 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
694                            struct iov_iter *iter)
695 {
696         memset(cs, 0, sizeof(*cs));
697         cs->write = write;
698         cs->iter = iter;
699 }
700
701 /* Unmap and put previous page of userspace buffer */
702 static void fuse_copy_finish(struct fuse_copy_state *cs)
703 {
704         if (cs->currbuf) {
705                 struct pipe_buffer *buf = cs->currbuf;
706
707                 if (cs->write)
708                         buf->len = PAGE_SIZE - cs->len;
709                 cs->currbuf = NULL;
710         } else if (cs->pg) {
711                 if (cs->write) {
712                         flush_dcache_page(cs->pg);
713                         set_page_dirty_lock(cs->pg);
714                 }
715                 put_page(cs->pg);
716         }
717         cs->pg = NULL;
718 }
719
720 /*
721  * Get another pagefull of userspace buffer, and map it to kernel
722  * address space, and lock request
723  */
724 static int fuse_copy_fill(struct fuse_copy_state *cs)
725 {
726         struct page *page;
727         int err;
728
729         err = unlock_request(cs->req);
730         if (err)
731                 return err;
732
733         fuse_copy_finish(cs);
734         if (cs->pipebufs) {
735                 struct pipe_buffer *buf = cs->pipebufs;
736
737                 if (!cs->write) {
738                         err = pipe_buf_confirm(cs->pipe, buf);
739                         if (err)
740                                 return err;
741
742                         BUG_ON(!cs->nr_segs);
743                         cs->currbuf = buf;
744                         cs->pg = buf->page;
745                         cs->offset = buf->offset;
746                         cs->len = buf->len;
747                         cs->pipebufs++;
748                         cs->nr_segs--;
749                 } else {
750                         if (cs->nr_segs == cs->pipe->buffers)
751                                 return -EIO;
752
753                         page = alloc_page(GFP_HIGHUSER);
754                         if (!page)
755                                 return -ENOMEM;
756
757                         buf->page = page;
758                         buf->offset = 0;
759                         buf->len = 0;
760
761                         cs->currbuf = buf;
762                         cs->pg = page;
763                         cs->offset = 0;
764                         cs->len = PAGE_SIZE;
765                         cs->pipebufs++;
766                         cs->nr_segs++;
767                 }
768         } else {
769                 size_t off;
770                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
771                 if (err < 0)
772                         return err;
773                 BUG_ON(!err);
774                 cs->len = err;
775                 cs->offset = off;
776                 cs->pg = page;
777                 iov_iter_advance(cs->iter, err);
778         }
779
780         return lock_request(cs->req);
781 }
782
783 /* Do as much copy to/from userspace buffer as we can */
784 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
785 {
786         unsigned ncpy = min(*size, cs->len);
787         if (val) {
788                 void *pgaddr = kmap_atomic(cs->pg);
789                 void *buf = pgaddr + cs->offset;
790
791                 if (cs->write)
792                         memcpy(buf, *val, ncpy);
793                 else
794                         memcpy(*val, buf, ncpy);
795
796                 kunmap_atomic(pgaddr);
797                 *val += ncpy;
798         }
799         *size -= ncpy;
800         cs->len -= ncpy;
801         cs->offset += ncpy;
802         return ncpy;
803 }
804
805 static int fuse_check_page(struct page *page)
806 {
807         if (page_mapcount(page) ||
808             page->mapping != NULL ||
809             page_count(page) != 1 ||
810             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
811              ~(1 << PG_locked |
812                1 << PG_referenced |
813                1 << PG_uptodate |
814                1 << PG_lru |
815                1 << PG_active |
816                1 << PG_reclaim))) {
817                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
818                 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);
819                 return 1;
820         }
821         return 0;
822 }
823
824 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
825 {
826         int err;
827         struct page *oldpage = *pagep;
828         struct page *newpage;
829         struct pipe_buffer *buf = cs->pipebufs;
830
831         err = unlock_request(cs->req);
832         if (err)
833                 return err;
834
835         fuse_copy_finish(cs);
836
837         err = pipe_buf_confirm(cs->pipe, buf);
838         if (err)
839                 return err;
840
841         BUG_ON(!cs->nr_segs);
842         cs->currbuf = buf;
843         cs->len = buf->len;
844         cs->pipebufs++;
845         cs->nr_segs--;
846
847         if (cs->len != PAGE_SIZE)
848                 goto out_fallback;
849
850         if (pipe_buf_steal(cs->pipe, buf) != 0)
851                 goto out_fallback;
852
853         newpage = buf->page;
854
855         if (!PageUptodate(newpage))
856                 SetPageUptodate(newpage);
857
858         ClearPageMappedToDisk(newpage);
859
860         if (fuse_check_page(newpage) != 0)
861                 goto out_fallback_unlock;
862
863         /*
864          * This is a new and locked page, it shouldn't be mapped or
865          * have any special flags on it
866          */
867         if (WARN_ON(page_mapped(oldpage)))
868                 goto out_fallback_unlock;
869         if (WARN_ON(page_has_private(oldpage)))
870                 goto out_fallback_unlock;
871         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
872                 goto out_fallback_unlock;
873         if (WARN_ON(PageMlocked(oldpage)))
874                 goto out_fallback_unlock;
875
876         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
877         if (err) {
878                 unlock_page(newpage);
879                 return err;
880         }
881
882         get_page(newpage);
883
884         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
885                 lru_cache_add_file(newpage);
886
887         err = 0;
888         spin_lock(&cs->req->waitq.lock);
889         if (test_bit(FR_ABORTED, &cs->req->flags))
890                 err = -ENOENT;
891         else
892                 *pagep = newpage;
893         spin_unlock(&cs->req->waitq.lock);
894
895         if (err) {
896                 unlock_page(newpage);
897                 put_page(newpage);
898                 return err;
899         }
900
901         unlock_page(oldpage);
902         put_page(oldpage);
903         cs->len = 0;
904
905         return 0;
906
907 out_fallback_unlock:
908         unlock_page(newpage);
909 out_fallback:
910         cs->pg = buf->page;
911         cs->offset = buf->offset;
912
913         err = lock_request(cs->req);
914         if (err)
915                 return err;
916
917         return 1;
918 }
919
920 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
921                          unsigned offset, unsigned count)
922 {
923         struct pipe_buffer *buf;
924         int err;
925
926         if (cs->nr_segs == cs->pipe->buffers)
927                 return -EIO;
928
929         err = unlock_request(cs->req);
930         if (err)
931                 return err;
932
933         fuse_copy_finish(cs);
934
935         buf = cs->pipebufs;
936         get_page(page);
937         buf->page = page;
938         buf->offset = offset;
939         buf->len = count;
940
941         cs->pipebufs++;
942         cs->nr_segs++;
943         cs->len = 0;
944
945         return 0;
946 }
947
948 /*
949  * Copy a page in the request to/from the userspace buffer.  Must be
950  * done atomically
951  */
952 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
953                           unsigned offset, unsigned count, int zeroing)
954 {
955         int err;
956         struct page *page = *pagep;
957
958         if (page && zeroing && count < PAGE_SIZE)
959                 clear_highpage(page);
960
961         while (count) {
962                 if (cs->write && cs->pipebufs && page) {
963                         return fuse_ref_page(cs, page, offset, count);
964                 } else if (!cs->len) {
965                         if (cs->move_pages && page &&
966                             offset == 0 && count == PAGE_SIZE) {
967                                 err = fuse_try_move_page(cs, pagep);
968                                 if (err <= 0)
969                                         return err;
970                         } else {
971                                 err = fuse_copy_fill(cs);
972                                 if (err)
973                                         return err;
974                         }
975                 }
976                 if (page) {
977                         void *mapaddr = kmap_atomic(page);
978                         void *buf = mapaddr + offset;
979                         offset += fuse_copy_do(cs, &buf, &count);
980                         kunmap_atomic(mapaddr);
981                 } else
982                         offset += fuse_copy_do(cs, NULL, &count);
983         }
984         if (page && !cs->write)
985                 flush_dcache_page(page);
986         return 0;
987 }
988
989 /* Copy pages in the request to/from userspace buffer */
990 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
991                            int zeroing)
992 {
993         unsigned i;
994         struct fuse_req *req = cs->req;
995
996         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
997                 int err;
998                 unsigned offset = req->page_descs[i].offset;
999                 unsigned count = min(nbytes, req->page_descs[i].length);
1000
1001                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1002                                      zeroing);
1003                 if (err)
1004                         return err;
1005
1006                 nbytes -= count;
1007         }
1008         return 0;
1009 }
1010
1011 /* Copy a single argument in the request to/from userspace buffer */
1012 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1013 {
1014         while (size) {
1015                 if (!cs->len) {
1016                         int err = fuse_copy_fill(cs);
1017                         if (err)
1018                                 return err;
1019                 }
1020                 fuse_copy_do(cs, &val, &size);
1021         }
1022         return 0;
1023 }
1024
1025 /* Copy request arguments to/from userspace buffer */
1026 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1027                           unsigned argpages, struct fuse_arg *args,
1028                           int zeroing)
1029 {
1030         int err = 0;
1031         unsigned i;
1032
1033         for (i = 0; !err && i < numargs; i++)  {
1034                 struct fuse_arg *arg = &args[i];
1035                 if (i == numargs - 1 && argpages)
1036                         err = fuse_copy_pages(cs, arg->size, zeroing);
1037                 else
1038                         err = fuse_copy_one(cs, arg->value, arg->size);
1039         }
1040         return err;
1041 }
1042
1043 static int forget_pending(struct fuse_iqueue *fiq)
1044 {
1045         return fiq->forget_list_head.next != NULL;
1046 }
1047
1048 static int request_pending(struct fuse_iqueue *fiq)
1049 {
1050         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1051                 forget_pending(fiq);
1052 }
1053
1054 /*
1055  * Transfer an interrupt request to userspace
1056  *
1057  * Unlike other requests this is assembled on demand, without a need
1058  * to allocate a separate fuse_req structure.
1059  *
1060  * Called with fiq->waitq.lock held, releases it
1061  */
1062 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1063                                struct fuse_copy_state *cs,
1064                                size_t nbytes, struct fuse_req *req)
1065 __releases(fiq->waitq.lock)
1066 {
1067         struct fuse_in_header ih;
1068         struct fuse_interrupt_in arg;
1069         unsigned reqsize = sizeof(ih) + sizeof(arg);
1070         int err;
1071
1072         list_del_init(&req->intr_entry);
1073         req->intr_unique = fuse_get_unique(fiq);
1074         memset(&ih, 0, sizeof(ih));
1075         memset(&arg, 0, sizeof(arg));
1076         ih.len = reqsize;
1077         ih.opcode = FUSE_INTERRUPT;
1078         ih.unique = req->intr_unique;
1079         arg.unique = req->in.h.unique;
1080
1081         spin_unlock(&fiq->waitq.lock);
1082         if (nbytes < reqsize)
1083                 return -EINVAL;
1084
1085         err = fuse_copy_one(cs, &ih, sizeof(ih));
1086         if (!err)
1087                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1088         fuse_copy_finish(cs);
1089
1090         return err ? err : reqsize;
1091 }
1092
1093 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1094                                                unsigned max,
1095                                                unsigned *countp)
1096 {
1097         struct fuse_forget_link *head = fiq->forget_list_head.next;
1098         struct fuse_forget_link **newhead = &head;
1099         unsigned count;
1100
1101         for (count = 0; *newhead != NULL && count < max; count++)
1102                 newhead = &(*newhead)->next;
1103
1104         fiq->forget_list_head.next = *newhead;
1105         *newhead = NULL;
1106         if (fiq->forget_list_head.next == NULL)
1107                 fiq->forget_list_tail = &fiq->forget_list_head;
1108
1109         if (countp != NULL)
1110                 *countp = count;
1111
1112         return head;
1113 }
1114
1115 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1116                                    struct fuse_copy_state *cs,
1117                                    size_t nbytes)
1118 __releases(fiq->waitq.lock)
1119 {
1120         int err;
1121         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1122         struct fuse_forget_in arg = {
1123                 .nlookup = forget->forget_one.nlookup,
1124         };
1125         struct fuse_in_header ih = {
1126                 .opcode = FUSE_FORGET,
1127                 .nodeid = forget->forget_one.nodeid,
1128                 .unique = fuse_get_unique(fiq),
1129                 .len = sizeof(ih) + sizeof(arg),
1130         };
1131
1132         spin_unlock(&fiq->waitq.lock);
1133         kfree(forget);
1134         if (nbytes < ih.len)
1135                 return -EINVAL;
1136
1137         err = fuse_copy_one(cs, &ih, sizeof(ih));
1138         if (!err)
1139                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1140         fuse_copy_finish(cs);
1141
1142         if (err)
1143                 return err;
1144
1145         return ih.len;
1146 }
1147
1148 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1149                                    struct fuse_copy_state *cs, size_t nbytes)
1150 __releases(fiq->waitq.lock)
1151 {
1152         int err;
1153         unsigned max_forgets;
1154         unsigned count;
1155         struct fuse_forget_link *head;
1156         struct fuse_batch_forget_in arg = { .count = 0 };
1157         struct fuse_in_header ih = {
1158                 .opcode = FUSE_BATCH_FORGET,
1159                 .unique = fuse_get_unique(fiq),
1160                 .len = sizeof(ih) + sizeof(arg),
1161         };
1162
1163         if (nbytes < ih.len) {
1164                 spin_unlock(&fiq->waitq.lock);
1165                 return -EINVAL;
1166         }
1167
1168         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1169         head = dequeue_forget(fiq, max_forgets, &count);
1170         spin_unlock(&fiq->waitq.lock);
1171
1172         arg.count = count;
1173         ih.len += count * sizeof(struct fuse_forget_one);
1174         err = fuse_copy_one(cs, &ih, sizeof(ih));
1175         if (!err)
1176                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1177
1178         while (head) {
1179                 struct fuse_forget_link *forget = head;
1180
1181                 if (!err) {
1182                         err = fuse_copy_one(cs, &forget->forget_one,
1183                                             sizeof(forget->forget_one));
1184                 }
1185                 head = forget->next;
1186                 kfree(forget);
1187         }
1188
1189         fuse_copy_finish(cs);
1190
1191         if (err)
1192                 return err;
1193
1194         return ih.len;
1195 }
1196
1197 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1198                             struct fuse_copy_state *cs,
1199                             size_t nbytes)
1200 __releases(fiq->waitq.lock)
1201 {
1202         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1203                 return fuse_read_single_forget(fiq, cs, nbytes);
1204         else
1205                 return fuse_read_batch_forget(fiq, cs, nbytes);
1206 }
1207
1208 /*
1209  * Read a single request into the userspace filesystem's buffer.  This
1210  * function waits until a request is available, then removes it from
1211  * the pending list and copies request data to userspace buffer.  If
1212  * no reply is needed (FORGET) or request has been aborted or there
1213  * was an error during the copying then it's finished by calling
1214  * request_end().  Otherwise add it to the processing list, and set
1215  * the 'sent' flag.
1216  */
1217 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1218                                 struct fuse_copy_state *cs, size_t nbytes)
1219 {
1220         ssize_t err;
1221         struct fuse_conn *fc = fud->fc;
1222         struct fuse_iqueue *fiq = &fc->iq;
1223         struct fuse_pqueue *fpq = &fud->pq;
1224         struct fuse_req *req;
1225         struct fuse_in *in;
1226         unsigned reqsize;
1227
1228  restart:
1229         spin_lock(&fiq->waitq.lock);
1230         err = -EAGAIN;
1231         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1232             !request_pending(fiq))
1233                 goto err_unlock;
1234
1235         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1236                                 !fiq->connected || request_pending(fiq));
1237         if (err)
1238                 goto err_unlock;
1239
1240         if (!fiq->connected) {
1241                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1242                 goto err_unlock;
1243         }
1244
1245         if (!list_empty(&fiq->interrupts)) {
1246                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1247                                  intr_entry);
1248                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1249         }
1250
1251         if (forget_pending(fiq)) {
1252                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1253                         return fuse_read_forget(fc, fiq, cs, nbytes);
1254
1255                 if (fiq->forget_batch <= -8)
1256                         fiq->forget_batch = 16;
1257         }
1258
1259         req = list_entry(fiq->pending.next, struct fuse_req, list);
1260         clear_bit(FR_PENDING, &req->flags);
1261         list_del_init(&req->list);
1262         spin_unlock(&fiq->waitq.lock);
1263
1264         in = &req->in;
1265         reqsize = in->h.len;
1266
1267         /* If request is too large, reply with an error and restart the read */
1268         if (nbytes < reqsize) {
1269                 req->out.h.error = -EIO;
1270                 /* SETXATTR is special, since it may contain too large data */
1271                 if (in->h.opcode == FUSE_SETXATTR)
1272                         req->out.h.error = -E2BIG;
1273                 request_end(fc, req);
1274                 goto restart;
1275         }
1276         spin_lock(&fpq->lock);
1277         list_add(&req->list, &fpq->io);
1278         spin_unlock(&fpq->lock);
1279         cs->req = req;
1280         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1281         if (!err)
1282                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1283                                      (struct fuse_arg *) in->args, 0);
1284         fuse_copy_finish(cs);
1285         spin_lock(&fpq->lock);
1286         clear_bit(FR_LOCKED, &req->flags);
1287         if (!fpq->connected) {
1288                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1289                 goto out_end;
1290         }
1291         if (err) {
1292                 req->out.h.error = -EIO;
1293                 goto out_end;
1294         }
1295         if (!test_bit(FR_ISREPLY, &req->flags)) {
1296                 err = reqsize;
1297                 goto out_end;
1298         }
1299         list_move_tail(&req->list, &fpq->processing);
1300         spin_unlock(&fpq->lock);
1301         set_bit(FR_SENT, &req->flags);
1302         /* matches barrier in request_wait_answer() */
1303         smp_mb__after_atomic();
1304         if (test_bit(FR_INTERRUPTED, &req->flags))
1305                 queue_interrupt(fiq, req);
1306
1307         return reqsize;
1308
1309 out_end:
1310         if (!test_bit(FR_PRIVATE, &req->flags))
1311                 list_del_init(&req->list);
1312         spin_unlock(&fpq->lock);
1313         request_end(fc, req);
1314         return err;
1315
1316  err_unlock:
1317         spin_unlock(&fiq->waitq.lock);
1318         return err;
1319 }
1320
1321 static int fuse_dev_open(struct inode *inode, struct file *file)
1322 {
1323         /*
1324          * The fuse device's file's private_data is used to hold
1325          * the fuse_conn(ection) when it is mounted, and is used to
1326          * keep track of whether the file has been mounted already.
1327          */
1328         file->private_data = NULL;
1329         return 0;
1330 }
1331
1332 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1333 {
1334         struct fuse_copy_state cs;
1335         struct file *file = iocb->ki_filp;
1336         struct fuse_dev *fud = fuse_get_dev(file);
1337
1338         if (!fud)
1339                 return -EPERM;
1340
1341         if (!iter_is_iovec(to))
1342                 return -EINVAL;
1343
1344         fuse_copy_init(&cs, 1, to);
1345
1346         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1347 }
1348
1349 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1350                                     struct pipe_inode_info *pipe,
1351                                     size_t len, unsigned int flags)
1352 {
1353         int total, ret;
1354         int page_nr = 0;
1355         struct pipe_buffer *bufs;
1356         struct fuse_copy_state cs;
1357         struct fuse_dev *fud = fuse_get_dev(in);
1358
1359         if (!fud)
1360                 return -EPERM;
1361
1362         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1363         if (!bufs)
1364                 return -ENOMEM;
1365
1366         fuse_copy_init(&cs, 1, NULL);
1367         cs.pipebufs = bufs;
1368         cs.pipe = pipe;
1369         ret = fuse_dev_do_read(fud, in, &cs, len);
1370         if (ret < 0)
1371                 goto out;
1372
1373         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1374                 ret = -EIO;
1375                 goto out;
1376         }
1377
1378         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1379                 /*
1380                  * Need to be careful about this.  Having buf->ops in module
1381                  * code can Oops if the buffer persists after module unload.
1382                  */
1383                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1384                 bufs[page_nr].flags = 0;
1385                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1386                 if (unlikely(ret < 0))
1387                         break;
1388         }
1389         if (total)
1390                 ret = total;
1391 out:
1392         for (; page_nr < cs.nr_segs; page_nr++)
1393                 put_page(bufs[page_nr].page);
1394
1395         kfree(bufs);
1396         return ret;
1397 }
1398
1399 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1400                             struct fuse_copy_state *cs)
1401 {
1402         struct fuse_notify_poll_wakeup_out outarg;
1403         int err = -EINVAL;
1404
1405         if (size != sizeof(outarg))
1406                 goto err;
1407
1408         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1409         if (err)
1410                 goto err;
1411
1412         fuse_copy_finish(cs);
1413         return fuse_notify_poll_wakeup(fc, &outarg);
1414
1415 err:
1416         fuse_copy_finish(cs);
1417         return err;
1418 }
1419
1420 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1421                                    struct fuse_copy_state *cs)
1422 {
1423         struct fuse_notify_inval_inode_out outarg;
1424         int err = -EINVAL;
1425
1426         if (size != sizeof(outarg))
1427                 goto err;
1428
1429         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1430         if (err)
1431                 goto err;
1432         fuse_copy_finish(cs);
1433
1434         down_read(&fc->killsb);
1435         err = -ENOENT;
1436         if (fc->sb) {
1437                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1438                                                outarg.off, outarg.len);
1439         }
1440         up_read(&fc->killsb);
1441         return err;
1442
1443 err:
1444         fuse_copy_finish(cs);
1445         return err;
1446 }
1447
1448 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1449                                    struct fuse_copy_state *cs)
1450 {
1451         struct fuse_notify_inval_entry_out outarg;
1452         int err = -ENOMEM;
1453         char *buf;
1454         struct qstr name;
1455
1456         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1457         if (!buf)
1458                 goto err;
1459
1460         err = -EINVAL;
1461         if (size < sizeof(outarg))
1462                 goto err;
1463
1464         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1465         if (err)
1466                 goto err;
1467
1468         err = -ENAMETOOLONG;
1469         if (outarg.namelen > FUSE_NAME_MAX)
1470                 goto err;
1471
1472         err = -EINVAL;
1473         if (size != sizeof(outarg) + outarg.namelen + 1)
1474                 goto err;
1475
1476         name.name = buf;
1477         name.len = outarg.namelen;
1478         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1479         if (err)
1480                 goto err;
1481         fuse_copy_finish(cs);
1482         buf[outarg.namelen] = 0;
1483
1484         down_read(&fc->killsb);
1485         err = -ENOENT;
1486         if (fc->sb)
1487                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1488         up_read(&fc->killsb);
1489         kfree(buf);
1490         return err;
1491
1492 err:
1493         kfree(buf);
1494         fuse_copy_finish(cs);
1495         return err;
1496 }
1497
1498 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1499                               struct fuse_copy_state *cs)
1500 {
1501         struct fuse_notify_delete_out outarg;
1502         int err = -ENOMEM;
1503         char *buf;
1504         struct qstr name;
1505
1506         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1507         if (!buf)
1508                 goto err;
1509
1510         err = -EINVAL;
1511         if (size < sizeof(outarg))
1512                 goto err;
1513
1514         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1515         if (err)
1516                 goto err;
1517
1518         err = -ENAMETOOLONG;
1519         if (outarg.namelen > FUSE_NAME_MAX)
1520                 goto err;
1521
1522         err = -EINVAL;
1523         if (size != sizeof(outarg) + outarg.namelen + 1)
1524                 goto err;
1525
1526         name.name = buf;
1527         name.len = outarg.namelen;
1528         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1529         if (err)
1530                 goto err;
1531         fuse_copy_finish(cs);
1532         buf[outarg.namelen] = 0;
1533
1534         down_read(&fc->killsb);
1535         err = -ENOENT;
1536         if (fc->sb)
1537                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1538                                                outarg.child, &name);
1539         up_read(&fc->killsb);
1540         kfree(buf);
1541         return err;
1542
1543 err:
1544         kfree(buf);
1545         fuse_copy_finish(cs);
1546         return err;
1547 }
1548
1549 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1550                              struct fuse_copy_state *cs)
1551 {
1552         struct fuse_notify_store_out outarg;
1553         struct inode *inode;
1554         struct address_space *mapping;
1555         u64 nodeid;
1556         int err;
1557         pgoff_t index;
1558         unsigned int offset;
1559         unsigned int num;
1560         loff_t file_size;
1561         loff_t end;
1562
1563         err = -EINVAL;
1564         if (size < sizeof(outarg))
1565                 goto out_finish;
1566
1567         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1568         if (err)
1569                 goto out_finish;
1570
1571         err = -EINVAL;
1572         if (size - sizeof(outarg) != outarg.size)
1573                 goto out_finish;
1574
1575         nodeid = outarg.nodeid;
1576
1577         down_read(&fc->killsb);
1578
1579         err = -ENOENT;
1580         if (!fc->sb)
1581                 goto out_up_killsb;
1582
1583         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1584         if (!inode)
1585                 goto out_up_killsb;
1586
1587         mapping = inode->i_mapping;
1588         index = outarg.offset >> PAGE_SHIFT;
1589         offset = outarg.offset & ~PAGE_MASK;
1590         file_size = i_size_read(inode);
1591         end = outarg.offset + outarg.size;
1592         if (end > file_size) {
1593                 file_size = end;
1594                 fuse_write_update_size(inode, file_size);
1595         }
1596
1597         num = outarg.size;
1598         while (num) {
1599                 struct page *page;
1600                 unsigned int this_num;
1601
1602                 err = -ENOMEM;
1603                 page = find_or_create_page(mapping, index,
1604                                            mapping_gfp_mask(mapping));
1605                 if (!page)
1606                         goto out_iput;
1607
1608                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1609                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1610                 if (!err && offset == 0 &&
1611                     (this_num == PAGE_SIZE || file_size == end))
1612                         SetPageUptodate(page);
1613                 unlock_page(page);
1614                 put_page(page);
1615
1616                 if (err)
1617                         goto out_iput;
1618
1619                 num -= this_num;
1620                 offset = 0;
1621                 index++;
1622         }
1623
1624         err = 0;
1625
1626 out_iput:
1627         iput(inode);
1628 out_up_killsb:
1629         up_read(&fc->killsb);
1630 out_finish:
1631         fuse_copy_finish(cs);
1632         return err;
1633 }
1634
1635 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1636 {
1637         release_pages(req->pages, req->num_pages);
1638 }
1639
1640 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1641                          struct fuse_notify_retrieve_out *outarg)
1642 {
1643         int err;
1644         struct address_space *mapping = inode->i_mapping;
1645         struct fuse_req *req;
1646         pgoff_t index;
1647         loff_t file_size;
1648         unsigned int num;
1649         unsigned int offset;
1650         size_t total_len = 0;
1651         int num_pages;
1652
1653         offset = outarg->offset & ~PAGE_MASK;
1654         file_size = i_size_read(inode);
1655
1656         num = outarg->size;
1657         if (outarg->offset > file_size)
1658                 num = 0;
1659         else if (outarg->offset + num > file_size)
1660                 num = file_size - outarg->offset;
1661
1662         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1663         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1664
1665         req = fuse_get_req(fc, num_pages);
1666         if (IS_ERR(req))
1667                 return PTR_ERR(req);
1668
1669         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1670         req->in.h.nodeid = outarg->nodeid;
1671         req->in.numargs = 2;
1672         req->in.argpages = 1;
1673         req->page_descs[0].offset = offset;
1674         req->end = fuse_retrieve_end;
1675
1676         index = outarg->offset >> PAGE_SHIFT;
1677
1678         while (num && req->num_pages < num_pages) {
1679                 struct page *page;
1680                 unsigned int this_num;
1681
1682                 page = find_get_page(mapping, index);
1683                 if (!page)
1684                         break;
1685
1686                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1687                 req->pages[req->num_pages] = page;
1688                 req->page_descs[req->num_pages].length = this_num;
1689                 req->num_pages++;
1690
1691                 offset = 0;
1692                 num -= this_num;
1693                 total_len += this_num;
1694                 index++;
1695         }
1696         req->misc.retrieve_in.offset = outarg->offset;
1697         req->misc.retrieve_in.size = total_len;
1698         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1699         req->in.args[0].value = &req->misc.retrieve_in;
1700         req->in.args[1].size = total_len;
1701
1702         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1703         if (err)
1704                 fuse_retrieve_end(fc, req);
1705
1706         return err;
1707 }
1708
1709 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1710                                 struct fuse_copy_state *cs)
1711 {
1712         struct fuse_notify_retrieve_out outarg;
1713         struct inode *inode;
1714         int err;
1715
1716         err = -EINVAL;
1717         if (size != sizeof(outarg))
1718                 goto copy_finish;
1719
1720         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1721         if (err)
1722                 goto copy_finish;
1723
1724         fuse_copy_finish(cs);
1725
1726         down_read(&fc->killsb);
1727         err = -ENOENT;
1728         if (fc->sb) {
1729                 u64 nodeid = outarg.nodeid;
1730
1731                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1732                 if (inode) {
1733                         err = fuse_retrieve(fc, inode, &outarg);
1734                         iput(inode);
1735                 }
1736         }
1737         up_read(&fc->killsb);
1738
1739         return err;
1740
1741 copy_finish:
1742         fuse_copy_finish(cs);
1743         return err;
1744 }
1745
1746 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1747                        unsigned int size, struct fuse_copy_state *cs)
1748 {
1749         /* Don't try to move pages (yet) */
1750         cs->move_pages = 0;
1751
1752         switch (code) {
1753         case FUSE_NOTIFY_POLL:
1754                 return fuse_notify_poll(fc, size, cs);
1755
1756         case FUSE_NOTIFY_INVAL_INODE:
1757                 return fuse_notify_inval_inode(fc, size, cs);
1758
1759         case FUSE_NOTIFY_INVAL_ENTRY:
1760                 return fuse_notify_inval_entry(fc, size, cs);
1761
1762         case FUSE_NOTIFY_STORE:
1763                 return fuse_notify_store(fc, size, cs);
1764
1765         case FUSE_NOTIFY_RETRIEVE:
1766                 return fuse_notify_retrieve(fc, size, cs);
1767
1768         case FUSE_NOTIFY_DELETE:
1769                 return fuse_notify_delete(fc, size, cs);
1770
1771         default:
1772                 fuse_copy_finish(cs);
1773                 return -EINVAL;
1774         }
1775 }
1776
1777 /* Look up request on processing list by unique ID */
1778 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1779 {
1780         struct fuse_req *req;
1781
1782         list_for_each_entry(req, &fpq->processing, list) {
1783                 if (req->in.h.unique == unique || req->intr_unique == unique)
1784                         return req;
1785         }
1786         return NULL;
1787 }
1788
1789 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1790                          unsigned nbytes)
1791 {
1792         unsigned reqsize = sizeof(struct fuse_out_header);
1793
1794         if (out->h.error)
1795                 return nbytes != reqsize ? -EINVAL : 0;
1796
1797         reqsize += len_args(out->numargs, out->args);
1798
1799         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1800                 return -EINVAL;
1801         else if (reqsize > nbytes) {
1802                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1803                 unsigned diffsize = reqsize - nbytes;
1804                 if (diffsize > lastarg->size)
1805                         return -EINVAL;
1806                 lastarg->size -= diffsize;
1807         }
1808         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1809                               out->page_zeroing);
1810 }
1811
1812 /*
1813  * Write a single reply to a request.  First the header is copied from
1814  * the write buffer.  The request is then searched on the processing
1815  * list by the unique ID found in the header.  If found, then remove
1816  * it from the list and copy the rest of the buffer to the request.
1817  * The request is finished by calling request_end()
1818  */
1819 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1820                                  struct fuse_copy_state *cs, size_t nbytes)
1821 {
1822         int err;
1823         struct fuse_conn *fc = fud->fc;
1824         struct fuse_pqueue *fpq = &fud->pq;
1825         struct fuse_req *req;
1826         struct fuse_out_header oh;
1827
1828         if (nbytes < sizeof(struct fuse_out_header))
1829                 return -EINVAL;
1830
1831         err = fuse_copy_one(cs, &oh, sizeof(oh));
1832         if (err)
1833                 goto err_finish;
1834
1835         err = -EINVAL;
1836         if (oh.len != nbytes)
1837                 goto err_finish;
1838
1839         /*
1840          * Zero oh.unique indicates unsolicited notification message
1841          * and error contains notification code.
1842          */
1843         if (!oh.unique) {
1844                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1845                 return err ? err : nbytes;
1846         }
1847
1848         err = -EINVAL;
1849         if (oh.error <= -1000 || oh.error > 0)
1850                 goto err_finish;
1851
1852         spin_lock(&fpq->lock);
1853         err = -ENOENT;
1854         if (!fpq->connected)
1855                 goto err_unlock_pq;
1856
1857         req = request_find(fpq, oh.unique);
1858         if (!req)
1859                 goto err_unlock_pq;
1860
1861         /* Is it an interrupt reply? */
1862         if (req->intr_unique == oh.unique) {
1863                 spin_unlock(&fpq->lock);
1864
1865                 err = -EINVAL;
1866                 if (nbytes != sizeof(struct fuse_out_header))
1867                         goto err_finish;
1868
1869                 if (oh.error == -ENOSYS)
1870                         fc->no_interrupt = 1;
1871                 else if (oh.error == -EAGAIN)
1872                         queue_interrupt(&fc->iq, req);
1873
1874                 fuse_copy_finish(cs);
1875                 return nbytes;
1876         }
1877
1878         clear_bit(FR_SENT, &req->flags);
1879         list_move(&req->list, &fpq->io);
1880         req->out.h = oh;
1881         set_bit(FR_LOCKED, &req->flags);
1882         spin_unlock(&fpq->lock);
1883         cs->req = req;
1884         if (!req->out.page_replace)
1885                 cs->move_pages = 0;
1886
1887         err = copy_out_args(cs, &req->out, nbytes);
1888         fuse_copy_finish(cs);
1889
1890         spin_lock(&fpq->lock);
1891         clear_bit(FR_LOCKED, &req->flags);
1892         if (!fpq->connected)
1893                 err = -ENOENT;
1894         else if (err)
1895                 req->out.h.error = -EIO;
1896         if (!test_bit(FR_PRIVATE, &req->flags))
1897                 list_del_init(&req->list);
1898         spin_unlock(&fpq->lock);
1899
1900         request_end(fc, req);
1901
1902         return err ? err : nbytes;
1903
1904  err_unlock_pq:
1905         spin_unlock(&fpq->lock);
1906  err_finish:
1907         fuse_copy_finish(cs);
1908         return err;
1909 }
1910
1911 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1912 {
1913         struct fuse_copy_state cs;
1914         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1915
1916         if (!fud)
1917                 return -EPERM;
1918
1919         if (!iter_is_iovec(from))
1920                 return -EINVAL;
1921
1922         fuse_copy_init(&cs, 0, from);
1923
1924         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1925 }
1926
1927 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1928                                      struct file *out, loff_t *ppos,
1929                                      size_t len, unsigned int flags)
1930 {
1931         unsigned nbuf;
1932         unsigned idx;
1933         struct pipe_buffer *bufs;
1934         struct fuse_copy_state cs;
1935         struct fuse_dev *fud;
1936         size_t rem;
1937         ssize_t ret;
1938
1939         fud = fuse_get_dev(out);
1940         if (!fud)
1941                 return -EPERM;
1942
1943         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1944         if (!bufs)
1945                 return -ENOMEM;
1946
1947         pipe_lock(pipe);
1948         nbuf = 0;
1949         rem = 0;
1950         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1951                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1952
1953         ret = -EINVAL;
1954         if (rem < len) {
1955                 pipe_unlock(pipe);
1956                 goto out;
1957         }
1958
1959         rem = len;
1960         while (rem) {
1961                 struct pipe_buffer *ibuf;
1962                 struct pipe_buffer *obuf;
1963
1964                 BUG_ON(nbuf >= pipe->buffers);
1965                 BUG_ON(!pipe->nrbufs);
1966                 ibuf = &pipe->bufs[pipe->curbuf];
1967                 obuf = &bufs[nbuf];
1968
1969                 if (rem >= ibuf->len) {
1970                         *obuf = *ibuf;
1971                         ibuf->ops = NULL;
1972                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1973                         pipe->nrbufs--;
1974                 } else {
1975                         pipe_buf_get(pipe, ibuf);
1976                         *obuf = *ibuf;
1977                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1978                         obuf->len = rem;
1979                         ibuf->offset += obuf->len;
1980                         ibuf->len -= obuf->len;
1981                 }
1982                 nbuf++;
1983                 rem -= obuf->len;
1984         }
1985         pipe_unlock(pipe);
1986
1987         fuse_copy_init(&cs, 0, NULL);
1988         cs.pipebufs = bufs;
1989         cs.nr_segs = nbuf;
1990         cs.pipe = pipe;
1991
1992         if (flags & SPLICE_F_MOVE)
1993                 cs.move_pages = 1;
1994
1995         ret = fuse_dev_do_write(fud, &cs, len);
1996
1997         for (idx = 0; idx < nbuf; idx++)
1998                 pipe_buf_release(pipe, &bufs[idx]);
1999
2000 out:
2001         kfree(bufs);
2002         return ret;
2003 }
2004
2005 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2006 {
2007         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2008         struct fuse_iqueue *fiq;
2009         struct fuse_dev *fud = fuse_get_dev(file);
2010
2011         if (!fud)
2012                 return EPOLLERR;
2013
2014         fiq = &fud->fc->iq;
2015         poll_wait(file, &fiq->waitq, wait);
2016
2017         spin_lock(&fiq->waitq.lock);
2018         if (!fiq->connected)
2019                 mask = EPOLLERR;
2020         else if (request_pending(fiq))
2021                 mask |= EPOLLIN | EPOLLRDNORM;
2022         spin_unlock(&fiq->waitq.lock);
2023
2024         return mask;
2025 }
2026
2027 /*
2028  * Abort all requests on the given list (pending or processing)
2029  *
2030  * This function releases and reacquires fc->lock
2031  */
2032 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2033 {
2034         while (!list_empty(head)) {
2035                 struct fuse_req *req;
2036                 req = list_entry(head->next, struct fuse_req, list);
2037                 req->out.h.error = -ECONNABORTED;
2038                 clear_bit(FR_SENT, &req->flags);
2039                 list_del_init(&req->list);
2040                 request_end(fc, req);
2041         }
2042 }
2043
2044 static void end_polls(struct fuse_conn *fc)
2045 {
2046         struct rb_node *p;
2047
2048         p = rb_first(&fc->polled_files);
2049
2050         while (p) {
2051                 struct fuse_file *ff;
2052                 ff = rb_entry(p, struct fuse_file, polled_node);
2053                 wake_up_interruptible_all(&ff->poll_wait);
2054
2055                 p = rb_next(p);
2056         }
2057 }
2058
2059 /*
2060  * Abort all requests.
2061  *
2062  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2063  * filesystem.
2064  *
2065  * The same effect is usually achievable through killing the filesystem daemon
2066  * and all users of the filesystem.  The exception is the combination of an
2067  * asynchronous request and the tricky deadlock (see
2068  * Documentation/filesystems/fuse.txt).
2069  *
2070  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2071  * requests, they should be finished off immediately.  Locked requests will be
2072  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2073  * requests.  It is possible that some request will finish before we can.  This
2074  * is OK, the request will in that case be removed from the list before we touch
2075  * it.
2076  */
2077 void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
2078 {
2079         struct fuse_iqueue *fiq = &fc->iq;
2080
2081         spin_lock(&fc->lock);
2082         if (fc->connected) {
2083                 struct fuse_dev *fud;
2084                 struct fuse_req *req, *next;
2085                 LIST_HEAD(to_end1);
2086                 LIST_HEAD(to_end2);
2087
2088                 fc->connected = 0;
2089                 fc->blocked = 0;
2090                 fc->aborted = is_abort;
2091                 fuse_set_initialized(fc);
2092                 list_for_each_entry(fud, &fc->devices, entry) {
2093                         struct fuse_pqueue *fpq = &fud->pq;
2094
2095                         spin_lock(&fpq->lock);
2096                         fpq->connected = 0;
2097                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2098                                 req->out.h.error = -ECONNABORTED;
2099                                 spin_lock(&req->waitq.lock);
2100                                 set_bit(FR_ABORTED, &req->flags);
2101                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2102                                         set_bit(FR_PRIVATE, &req->flags);
2103                                         list_move(&req->list, &to_end1);
2104                                 }
2105                                 spin_unlock(&req->waitq.lock);
2106                         }
2107                         list_splice_init(&fpq->processing, &to_end2);
2108                         spin_unlock(&fpq->lock);
2109                 }
2110                 fc->max_background = UINT_MAX;
2111                 flush_bg_queue(fc);
2112
2113                 spin_lock(&fiq->waitq.lock);
2114                 fiq->connected = 0;
2115                 list_splice_init(&fiq->pending, &to_end2);
2116                 list_for_each_entry(req, &to_end2, list)
2117                         clear_bit(FR_PENDING, &req->flags);
2118                 while (forget_pending(fiq))
2119                         kfree(dequeue_forget(fiq, 1, NULL));
2120                 wake_up_all_locked(&fiq->waitq);
2121                 spin_unlock(&fiq->waitq.lock);
2122                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2123                 end_polls(fc);
2124                 wake_up_all(&fc->blocked_waitq);
2125                 spin_unlock(&fc->lock);
2126
2127                 while (!list_empty(&to_end1)) {
2128                         req = list_first_entry(&to_end1, struct fuse_req, list);
2129                         __fuse_get_request(req);
2130                         list_del_init(&req->list);
2131                         request_end(fc, req);
2132                 }
2133                 end_requests(fc, &to_end2);
2134         } else {
2135                 spin_unlock(&fc->lock);
2136         }
2137 }
2138 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2139
2140 int fuse_dev_release(struct inode *inode, struct file *file)
2141 {
2142         struct fuse_dev *fud = fuse_get_dev(file);
2143
2144         if (fud) {
2145                 struct fuse_conn *fc = fud->fc;
2146                 struct fuse_pqueue *fpq = &fud->pq;
2147
2148                 WARN_ON(!list_empty(&fpq->io));
2149                 end_requests(fc, &fpq->processing);
2150                 /* Are we the last open device? */
2151                 if (atomic_dec_and_test(&fc->dev_count)) {
2152                         WARN_ON(fc->iq.fasync != NULL);
2153                         fuse_abort_conn(fc, false);
2154                 }
2155                 fuse_dev_free(fud);
2156         }
2157         return 0;
2158 }
2159 EXPORT_SYMBOL_GPL(fuse_dev_release);
2160
2161 static int fuse_dev_fasync(int fd, struct file *file, int on)
2162 {
2163         struct fuse_dev *fud = fuse_get_dev(file);
2164
2165         if (!fud)
2166                 return -EPERM;
2167
2168         /* No locking - fasync_helper does its own locking */
2169         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2170 }
2171
2172 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2173 {
2174         struct fuse_dev *fud;
2175
2176         if (new->private_data)
2177                 return -EINVAL;
2178
2179         fud = fuse_dev_alloc(fc);
2180         if (!fud)
2181                 return -ENOMEM;
2182
2183         new->private_data = fud;
2184         atomic_inc(&fc->dev_count);
2185
2186         return 0;
2187 }
2188
2189 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2190                            unsigned long arg)
2191 {
2192         int err = -ENOTTY;
2193
2194         if (cmd == FUSE_DEV_IOC_CLONE) {
2195                 int oldfd;
2196
2197                 err = -EFAULT;
2198                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2199                         struct file *old = fget(oldfd);
2200
2201                         err = -EINVAL;
2202                         if (old) {
2203                                 struct fuse_dev *fud = NULL;
2204
2205                                 /*
2206                                  * Check against file->f_op because CUSE
2207                                  * uses the same ioctl handler.
2208                                  */
2209                                 if (old->f_op == file->f_op &&
2210                                     old->f_cred->user_ns == file->f_cred->user_ns)
2211                                         fud = fuse_get_dev(old);
2212
2213                                 if (fud) {
2214                                         mutex_lock(&fuse_mutex);
2215                                         err = fuse_device_clone(fud->fc, file);
2216                                         mutex_unlock(&fuse_mutex);
2217                                 }
2218                                 fput(old);
2219                         }
2220                 }
2221         }
2222         return err;
2223 }
2224
2225 const struct file_operations fuse_dev_operations = {
2226         .owner          = THIS_MODULE,
2227         .open           = fuse_dev_open,
2228         .llseek         = no_llseek,
2229         .read_iter      = fuse_dev_read,
2230         .splice_read    = fuse_dev_splice_read,
2231         .write_iter     = fuse_dev_write,
2232         .splice_write   = fuse_dev_splice_write,
2233         .poll           = fuse_dev_poll,
2234         .release        = fuse_dev_release,
2235         .fasync         = fuse_dev_fasync,
2236         .unlocked_ioctl = fuse_dev_ioctl,
2237         .compat_ioctl   = fuse_dev_ioctl,
2238 };
2239 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2240
2241 static struct miscdevice fuse_miscdevice = {
2242         .minor = FUSE_MINOR,
2243         .name  = "fuse",
2244         .fops = &fuse_dev_operations,
2245 };
2246
2247 int __init fuse_dev_init(void)
2248 {
2249         int err = -ENOMEM;
2250         fuse_req_cachep = kmem_cache_create("fuse_request",
2251                                             sizeof(struct fuse_req),
2252                                             0, 0, NULL);
2253         if (!fuse_req_cachep)
2254                 goto out;
2255
2256         err = misc_register(&fuse_miscdevice);
2257         if (err)
2258                 goto out_cache_clean;
2259
2260         return 0;
2261
2262  out_cache_clean:
2263         kmem_cache_destroy(fuse_req_cachep);
2264  out:
2265         return err;
2266 }
2267
2268 void fuse_dev_cleanup(void)
2269 {
2270         misc_deregister(&fuse_miscdevice);
2271         kmem_cache_destroy(fuse_req_cachep);
2272 }