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Linux/fs/fuse/dev.c

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  1 /*
  2   FUSE: Filesystem in Userspace
  3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
  4 
  5   This program can be distributed under the terms of the GNU GPL.
  6   See the file COPYING.
  7 */
  8 
  9 #include "fuse_i.h"
 10 
 11 #include <linux/init.h>
 12 #include <linux/module.h>
 13 #include <linux/poll.h>
 14 #include <linux/uio.h>
 15 #include <linux/miscdevice.h>
 16 #include <linux/pagemap.h>
 17 #include <linux/file.h>
 18 #include <linux/slab.h>
 19 #include <linux/pipe_fs_i.h>
 20 #include <linux/swap.h>
 21 #include <linux/splice.h>
 22 
 23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
 24 MODULE_ALIAS("devname:fuse");
 25 
 26 static struct kmem_cache *fuse_req_cachep;
 27 
 28 static struct fuse_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 
 37 static void fuse_request_init(struct fuse_req *req, struct page **pages,
 38                               struct fuse_page_desc *page_descs,
 39                               unsigned npages)
 40 {
 41         memset(req, 0, sizeof(*req));
 42         memset(pages, 0, sizeof(*pages) * npages);
 43         memset(page_descs, 0, sizeof(*page_descs) * npages);
 44         INIT_LIST_HEAD(&req->list);
 45         INIT_LIST_HEAD(&req->intr_entry);
 46         init_waitqueue_head(&req->waitq);
 47         atomic_set(&req->count, 1);
 48         req->pages = pages;
 49         req->page_descs = page_descs;
 50         req->max_pages = npages;
 51         __set_bit(FR_PENDING, &req->flags);
 52 }
 53 
 54 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
 55 {
 56         struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
 57         if (req) {
 58                 struct page **pages;
 59                 struct fuse_page_desc *page_descs;
 60 
 61                 if (npages <= FUSE_REQ_INLINE_PAGES) {
 62                         pages = req->inline_pages;
 63                         page_descs = req->inline_page_descs;
 64                 } else {
 65                         pages = kmalloc(sizeof(struct page *) * npages, flags);
 66                         page_descs = kmalloc(sizeof(struct fuse_page_desc) *
 67                                              npages, flags);
 68                 }
 69 
 70                 if (!pages || !page_descs) {
 71                         kfree(pages);
 72                         kfree(page_descs);
 73                         kmem_cache_free(fuse_req_cachep, req);
 74                         return NULL;
 75                 }
 76 
 77                 fuse_request_init(req, pages, page_descs, npages);
 78         }
 79         return req;
 80 }
 81 
 82 struct fuse_req *fuse_request_alloc(unsigned npages)
 83 {
 84         return __fuse_request_alloc(npages, GFP_KERNEL);
 85 }
 86 EXPORT_SYMBOL_GPL(fuse_request_alloc);
 87 
 88 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
 89 {
 90         return __fuse_request_alloc(npages, GFP_NOFS);
 91 }
 92 
 93 void fuse_request_free(struct fuse_req *req)
 94 {
 95         if (req->pages != req->inline_pages) {
 96                 kfree(req->pages);
 97                 kfree(req->page_descs);
 98         }
 99         kmem_cache_free(fuse_req_cachep, req);
100 }
101 
102 static void block_sigs(sigset_t *oldset)
103 {
104         sigset_t mask;
105 
106         siginitsetinv(&mask, sigmask(SIGKILL));
107         sigprocmask(SIG_BLOCK, &mask, oldset);
108 }
109 
110 static void restore_sigs(sigset_t *oldset)
111 {
112         sigprocmask(SIG_SETMASK, oldset, NULL);
113 }
114 
115 void __fuse_get_request(struct fuse_req *req)
116 {
117         atomic_inc(&req->count);
118 }
119 
120 /* Must be called with > 1 refcount */
121 static void __fuse_put_request(struct fuse_req *req)
122 {
123         BUG_ON(atomic_read(&req->count) < 2);
124         atomic_dec(&req->count);
125 }
126 
127 static void fuse_req_init_context(struct fuse_req *req)
128 {
129         req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
130         req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
131         req->in.h.pid = current->pid;
132 }
133 
134 void fuse_set_initialized(struct fuse_conn *fc)
135 {
136         /* Make sure stores before this are seen on another CPU */
137         smp_wmb();
138         fc->initialized = 1;
139 }
140 
141 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
142 {
143         return !fc->initialized || (for_background && fc->blocked);
144 }
145 
146 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
147                                        bool for_background)
148 {
149         struct fuse_req *req;
150         int err;
151         atomic_inc(&fc->num_waiting);
152 
153         if (fuse_block_alloc(fc, for_background)) {
154                 sigset_t oldset;
155                 int intr;
156 
157                 block_sigs(&oldset);
158                 intr = wait_event_interruptible_exclusive(fc->blocked_waitq,
159                                 !fuse_block_alloc(fc, for_background));
160                 restore_sigs(&oldset);
161                 err = -EINTR;
162                 if (intr)
163                         goto out;
164         }
165         /* Matches smp_wmb() in fuse_set_initialized() */
166         smp_rmb();
167 
168         err = -ENOTCONN;
169         if (!fc->connected)
170                 goto out;
171 
172         err = -ECONNREFUSED;
173         if (fc->conn_error)
174                 goto out;
175 
176         req = fuse_request_alloc(npages);
177         err = -ENOMEM;
178         if (!req) {
179                 if (for_background)
180                         wake_up(&fc->blocked_waitq);
181                 goto out;
182         }
183 
184         fuse_req_init_context(req);
185         __set_bit(FR_WAITING, &req->flags);
186         if (for_background)
187                 __set_bit(FR_BACKGROUND, &req->flags);
188 
189         return req;
190 
191  out:
192         atomic_dec(&fc->num_waiting);
193         return ERR_PTR(err);
194 }
195 
196 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
197 {
198         return __fuse_get_req(fc, npages, false);
199 }
200 EXPORT_SYMBOL_GPL(fuse_get_req);
201 
202 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
203                                              unsigned npages)
204 {
205         return __fuse_get_req(fc, npages, true);
206 }
207 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
208 
209 /*
210  * Return request in fuse_file->reserved_req.  However that may
211  * currently be in use.  If that is the case, wait for it to become
212  * available.
213  */
214 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
215                                          struct file *file)
216 {
217         struct fuse_req *req = NULL;
218         struct fuse_file *ff = file->private_data;
219 
220         do {
221                 wait_event(fc->reserved_req_waitq, ff->reserved_req);
222                 spin_lock(&fc->lock);
223                 if (ff->reserved_req) {
224                         req = ff->reserved_req;
225                         ff->reserved_req = NULL;
226                         req->stolen_file = get_file(file);
227                 }
228                 spin_unlock(&fc->lock);
229         } while (!req);
230 
231         return req;
232 }
233 
234 /*
235  * Put stolen request back into fuse_file->reserved_req
236  */
237 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
238 {
239         struct file *file = req->stolen_file;
240         struct fuse_file *ff = file->private_data;
241 
242         spin_lock(&fc->lock);
243         fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
244         BUG_ON(ff->reserved_req);
245         ff->reserved_req = req;
246         wake_up_all(&fc->reserved_req_waitq);
247         spin_unlock(&fc->lock);
248         fput(file);
249 }
250 
251 /*
252  * Gets a requests for a file operation, always succeeds
253  *
254  * This is used for sending the FLUSH request, which must get to
255  * userspace, due to POSIX locks which may need to be unlocked.
256  *
257  * If allocation fails due to OOM, use the reserved request in
258  * fuse_file.
259  *
260  * This is very unlikely to deadlock accidentally, since the
261  * filesystem should not have it's own file open.  If deadlock is
262  * intentional, it can still be broken by "aborting" the filesystem.
263  */
264 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
265                                              struct file *file)
266 {
267         struct fuse_req *req;
268 
269         atomic_inc(&fc->num_waiting);
270         wait_event(fc->blocked_waitq, fc->initialized);
271         /* Matches smp_wmb() in fuse_set_initialized() */
272         smp_rmb();
273         req = fuse_request_alloc(0);
274         if (!req)
275                 req = get_reserved_req(fc, file);
276 
277         fuse_req_init_context(req);
278         __set_bit(FR_WAITING, &req->flags);
279         __clear_bit(FR_BACKGROUND, &req->flags);
280         return req;
281 }
282 
283 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
284 {
285         if (atomic_dec_and_test(&req->count)) {
286                 if (test_bit(FR_BACKGROUND, &req->flags)) {
287                         /*
288                          * We get here in the unlikely case that a background
289                          * request was allocated but not sent
290                          */
291                         spin_lock(&fc->lock);
292                         if (!fc->blocked)
293                                 wake_up(&fc->blocked_waitq);
294                         spin_unlock(&fc->lock);
295                 }
296 
297                 if (test_bit(FR_WAITING, &req->flags)) {
298                         __clear_bit(FR_WAITING, &req->flags);
299                         atomic_dec(&fc->num_waiting);
300                 }
301 
302                 if (req->stolen_file)
303                         put_reserved_req(fc, req);
304                 else
305                         fuse_request_free(req);
306         }
307 }
308 EXPORT_SYMBOL_GPL(fuse_put_request);
309 
310 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
311 {
312         unsigned nbytes = 0;
313         unsigned i;
314 
315         for (i = 0; i < numargs; i++)
316                 nbytes += args[i].size;
317 
318         return nbytes;
319 }
320 
321 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
322 {
323         return ++fiq->reqctr;
324 }
325 
326 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
327 {
328         req->in.h.len = sizeof(struct fuse_in_header) +
329                 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
330         list_add_tail(&req->list, &fiq->pending);
331         wake_up_locked(&fiq->waitq);
332         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
333 }
334 
335 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
336                        u64 nodeid, u64 nlookup)
337 {
338         struct fuse_iqueue *fiq = &fc->iq;
339 
340         forget->forget_one.nodeid = nodeid;
341         forget->forget_one.nlookup = nlookup;
342 
343         spin_lock(&fiq->waitq.lock);
344         if (fiq->connected) {
345                 fiq->forget_list_tail->next = forget;
346                 fiq->forget_list_tail = forget;
347                 wake_up_locked(&fiq->waitq);
348                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
349         } else {
350                 kfree(forget);
351         }
352         spin_unlock(&fiq->waitq.lock);
353 }
354 
355 static void flush_bg_queue(struct fuse_conn *fc)
356 {
357         while (fc->active_background < fc->max_background &&
358                !list_empty(&fc->bg_queue)) {
359                 struct fuse_req *req;
360                 struct fuse_iqueue *fiq = &fc->iq;
361 
362                 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
363                 list_del(&req->list);
364                 fc->active_background++;
365                 spin_lock(&fiq->waitq.lock);
366                 req->in.h.unique = fuse_get_unique(fiq);
367                 queue_request(fiq, req);
368                 spin_unlock(&fiq->waitq.lock);
369         }
370 }
371 
372 /*
373  * This function is called when a request is finished.  Either a reply
374  * has arrived or it was aborted (and not yet sent) or some error
375  * occurred during communication with userspace, or the device file
376  * was closed.  The requester thread is woken up (if still waiting),
377  * the 'end' callback is called if given, else the reference to the
378  * request is released
379  */
380 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
381 {
382         struct fuse_iqueue *fiq = &fc->iq;
383 
384         if (test_and_set_bit(FR_FINISHED, &req->flags))
385                 return;
386 
387         spin_lock(&fiq->waitq.lock);
388         list_del_init(&req->intr_entry);
389         spin_unlock(&fiq->waitq.lock);
390         WARN_ON(test_bit(FR_PENDING, &req->flags));
391         WARN_ON(test_bit(FR_SENT, &req->flags));
392         if (test_bit(FR_BACKGROUND, &req->flags)) {
393                 spin_lock(&fc->lock);
394                 clear_bit(FR_BACKGROUND, &req->flags);
395                 if (fc->num_background == fc->max_background)
396                         fc->blocked = 0;
397 
398                 /* Wake up next waiter, if any */
399                 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
400                         wake_up(&fc->blocked_waitq);
401 
402                 if (fc->num_background == fc->congestion_threshold &&
403                     fc->connected && fc->bdi_initialized) {
404                         clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
405                         clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
406                 }
407                 fc->num_background--;
408                 fc->active_background--;
409                 flush_bg_queue(fc);
410                 spin_unlock(&fc->lock);
411         }
412         wake_up(&req->waitq);
413         if (req->end)
414                 req->end(fc, req);
415         fuse_put_request(fc, req);
416 }
417 
418 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
419 {
420         spin_lock(&fiq->waitq.lock);
421         if (list_empty(&req->intr_entry)) {
422                 list_add_tail(&req->intr_entry, &fiq->interrupts);
423                 wake_up_locked(&fiq->waitq);
424         }
425         spin_unlock(&fiq->waitq.lock);
426         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
427 }
428 
429 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
430 {
431         struct fuse_iqueue *fiq = &fc->iq;
432         int err;
433 
434         if (!fc->no_interrupt) {
435                 /* Any signal may interrupt this */
436                 err = wait_event_interruptible(req->waitq,
437                                         test_bit(FR_FINISHED, &req->flags));
438                 if (!err)
439                         return;
440 
441                 set_bit(FR_INTERRUPTED, &req->flags);
442                 /* matches barrier in fuse_dev_do_read() */
443                 smp_mb__after_atomic();
444                 if (test_bit(FR_SENT, &req->flags))
445                         queue_interrupt(fiq, req);
446         }
447 
448         if (!test_bit(FR_FORCE, &req->flags)) {
449                 sigset_t oldset;
450 
451                 /* Only fatal signals may interrupt this */
452                 block_sigs(&oldset);
453                 err = wait_event_interruptible(req->waitq,
454                                         test_bit(FR_FINISHED, &req->flags));
455                 restore_sigs(&oldset);
456 
457                 if (!err)
458                         return;
459 
460                 spin_lock(&fiq->waitq.lock);
461                 /* Request is not yet in userspace, bail out */
462                 if (test_bit(FR_PENDING, &req->flags)) {
463                         list_del(&req->list);
464                         spin_unlock(&fiq->waitq.lock);
465                         __fuse_put_request(req);
466                         req->out.h.error = -EINTR;
467                         return;
468                 }
469                 spin_unlock(&fiq->waitq.lock);
470         }
471 
472         /*
473          * Either request is already in userspace, or it was forced.
474          * Wait it out.
475          */
476         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
477 }
478 
479 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
480 {
481         struct fuse_iqueue *fiq = &fc->iq;
482 
483         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
484         spin_lock(&fiq->waitq.lock);
485         if (!fiq->connected) {
486                 spin_unlock(&fiq->waitq.lock);
487                 req->out.h.error = -ENOTCONN;
488         } else {
489                 req->in.h.unique = fuse_get_unique(fiq);
490                 queue_request(fiq, req);
491                 /* acquire extra reference, since request is still needed
492                    after request_end() */
493                 __fuse_get_request(req);
494                 spin_unlock(&fiq->waitq.lock);
495 
496                 request_wait_answer(fc, req);
497                 /* Pairs with smp_wmb() in request_end() */
498                 smp_rmb();
499         }
500 }
501 
502 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
503 {
504         __set_bit(FR_ISREPLY, &req->flags);
505         if (!test_bit(FR_WAITING, &req->flags)) {
506                 __set_bit(FR_WAITING, &req->flags);
507                 atomic_inc(&fc->num_waiting);
508         }
509         __fuse_request_send(fc, req);
510 }
511 EXPORT_SYMBOL_GPL(fuse_request_send);
512 
513 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
514 {
515         if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
516                 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
517 
518         if (fc->minor < 9) {
519                 switch (args->in.h.opcode) {
520                 case FUSE_LOOKUP:
521                 case FUSE_CREATE:
522                 case FUSE_MKNOD:
523                 case FUSE_MKDIR:
524                 case FUSE_SYMLINK:
525                 case FUSE_LINK:
526                         args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
527                         break;
528                 case FUSE_GETATTR:
529                 case FUSE_SETATTR:
530                         args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
531                         break;
532                 }
533         }
534         if (fc->minor < 12) {
535                 switch (args->in.h.opcode) {
536                 case FUSE_CREATE:
537                         args->in.args[0].size = sizeof(struct fuse_open_in);
538                         break;
539                 case FUSE_MKNOD:
540                         args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
541                         break;
542                 }
543         }
544 }
545 
546 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
547 {
548         struct fuse_req *req;
549         ssize_t ret;
550 
551         req = fuse_get_req(fc, 0);
552         if (IS_ERR(req))
553                 return PTR_ERR(req);
554 
555         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
556         fuse_adjust_compat(fc, args);
557 
558         req->in.h.opcode = args->in.h.opcode;
559         req->in.h.nodeid = args->in.h.nodeid;
560         req->in.numargs = args->in.numargs;
561         memcpy(req->in.args, args->in.args,
562                args->in.numargs * sizeof(struct fuse_in_arg));
563         req->out.argvar = args->out.argvar;
564         req->out.numargs = args->out.numargs;
565         memcpy(req->out.args, args->out.args,
566                args->out.numargs * sizeof(struct fuse_arg));
567         fuse_request_send(fc, req);
568         ret = req->out.h.error;
569         if (!ret && args->out.argvar) {
570                 BUG_ON(args->out.numargs != 1);
571                 ret = req->out.args[0].size;
572         }
573         fuse_put_request(fc, req);
574 
575         return ret;
576 }
577 
578 /*
579  * Called under fc->lock
580  *
581  * fc->connected must have been checked previously
582  */
583 void fuse_request_send_background_locked(struct fuse_conn *fc,
584                                          struct fuse_req *req)
585 {
586         BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
587         if (!test_bit(FR_WAITING, &req->flags)) {
588                 __set_bit(FR_WAITING, &req->flags);
589                 atomic_inc(&fc->num_waiting);
590         }
591         __set_bit(FR_ISREPLY, &req->flags);
592         fc->num_background++;
593         if (fc->num_background == fc->max_background)
594                 fc->blocked = 1;
595         if (fc->num_background == fc->congestion_threshold &&
596             fc->bdi_initialized) {
597                 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
598                 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
599         }
600         list_add_tail(&req->list, &fc->bg_queue);
601         flush_bg_queue(fc);
602 }
603 
604 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
605 {
606         BUG_ON(!req->end);
607         spin_lock(&fc->lock);
608         if (fc->connected) {
609                 fuse_request_send_background_locked(fc, req);
610                 spin_unlock(&fc->lock);
611         } else {
612                 spin_unlock(&fc->lock);
613                 req->out.h.error = -ENOTCONN;
614                 req->end(fc, req);
615                 fuse_put_request(fc, req);
616         }
617 }
618 EXPORT_SYMBOL_GPL(fuse_request_send_background);
619 
620 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
621                                           struct fuse_req *req, u64 unique)
622 {
623         int err = -ENODEV;
624         struct fuse_iqueue *fiq = &fc->iq;
625 
626         __clear_bit(FR_ISREPLY, &req->flags);
627         req->in.h.unique = unique;
628         spin_lock(&fiq->waitq.lock);
629         if (fiq->connected) {
630                 queue_request(fiq, req);
631                 err = 0;
632         }
633         spin_unlock(&fiq->waitq.lock);
634 
635         return err;
636 }
637 
638 void fuse_force_forget(struct file *file, u64 nodeid)
639 {
640         struct inode *inode = file_inode(file);
641         struct fuse_conn *fc = get_fuse_conn(inode);
642         struct fuse_req *req;
643         struct fuse_forget_in inarg;
644 
645         memset(&inarg, 0, sizeof(inarg));
646         inarg.nlookup = 1;
647         req = fuse_get_req_nofail_nopages(fc, file);
648         req->in.h.opcode = FUSE_FORGET;
649         req->in.h.nodeid = nodeid;
650         req->in.numargs = 1;
651         req->in.args[0].size = sizeof(inarg);
652         req->in.args[0].value = &inarg;
653         __clear_bit(FR_ISREPLY, &req->flags);
654         __fuse_request_send(fc, req);
655         /* ignore errors */
656         fuse_put_request(fc, req);
657 }
658 
659 /*
660  * Lock the request.  Up to the next unlock_request() there mustn't be
661  * anything that could cause a page-fault.  If the request was already
662  * aborted bail out.
663  */
664 static int lock_request(struct fuse_req *req)
665 {
666         int err = 0;
667         if (req) {
668                 spin_lock(&req->waitq.lock);
669                 if (test_bit(FR_ABORTED, &req->flags))
670                         err = -ENOENT;
671                 else
672                         set_bit(FR_LOCKED, &req->flags);
673                 spin_unlock(&req->waitq.lock);
674         }
675         return err;
676 }
677 
678 /*
679  * Unlock request.  If it was aborted while locked, caller is responsible
680  * for unlocking and ending the request.
681  */
682 static int unlock_request(struct fuse_req *req)
683 {
684         int err = 0;
685         if (req) {
686                 spin_lock(&req->waitq.lock);
687                 if (test_bit(FR_ABORTED, &req->flags))
688                         err = -ENOENT;
689                 else
690                         clear_bit(FR_LOCKED, &req->flags);
691                 spin_unlock(&req->waitq.lock);
692         }
693         return err;
694 }
695 
696 struct fuse_copy_state {
697         int write;
698         struct fuse_req *req;
699         struct iov_iter *iter;
700         struct pipe_buffer *pipebufs;
701         struct pipe_buffer *currbuf;
702         struct pipe_inode_info *pipe;
703         unsigned long nr_segs;
704         struct page *pg;
705         unsigned len;
706         unsigned offset;
707         unsigned move_pages:1;
708 };
709 
710 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
711                            struct iov_iter *iter)
712 {
713         memset(cs, 0, sizeof(*cs));
714         cs->write = write;
715         cs->iter = iter;
716 }
717 
718 /* Unmap and put previous page of userspace buffer */
719 static void fuse_copy_finish(struct fuse_copy_state *cs)
720 {
721         if (cs->currbuf) {
722                 struct pipe_buffer *buf = cs->currbuf;
723 
724                 if (cs->write)
725                         buf->len = PAGE_SIZE - cs->len;
726                 cs->currbuf = NULL;
727         } else if (cs->pg) {
728                 if (cs->write) {
729                         flush_dcache_page(cs->pg);
730                         set_page_dirty_lock(cs->pg);
731                 }
732                 put_page(cs->pg);
733         }
734         cs->pg = NULL;
735 }
736 
737 /*
738  * Get another pagefull of userspace buffer, and map it to kernel
739  * address space, and lock request
740  */
741 static int fuse_copy_fill(struct fuse_copy_state *cs)
742 {
743         struct page *page;
744         int err;
745 
746         err = unlock_request(cs->req);
747         if (err)
748                 return err;
749 
750         fuse_copy_finish(cs);
751         if (cs->pipebufs) {
752                 struct pipe_buffer *buf = cs->pipebufs;
753 
754                 if (!cs->write) {
755                         err = buf->ops->confirm(cs->pipe, buf);
756                         if (err)
757                                 return err;
758 
759                         BUG_ON(!cs->nr_segs);
760                         cs->currbuf = buf;
761                         cs->pg = buf->page;
762                         cs->offset = buf->offset;
763                         cs->len = buf->len;
764                         cs->pipebufs++;
765                         cs->nr_segs--;
766                 } else {
767                         if (cs->nr_segs == cs->pipe->buffers)
768                                 return -EIO;
769 
770                         page = alloc_page(GFP_HIGHUSER);
771                         if (!page)
772                                 return -ENOMEM;
773 
774                         buf->page = page;
775                         buf->offset = 0;
776                         buf->len = 0;
777 
778                         cs->currbuf = buf;
779                         cs->pg = page;
780                         cs->offset = 0;
781                         cs->len = PAGE_SIZE;
782                         cs->pipebufs++;
783                         cs->nr_segs++;
784                 }
785         } else {
786                 size_t off;
787                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
788                 if (err < 0)
789                         return err;
790                 BUG_ON(!err);
791                 cs->len = err;
792                 cs->offset = off;
793                 cs->pg = page;
794                 cs->offset = off;
795                 iov_iter_advance(cs->iter, err);
796         }
797 
798         return lock_request(cs->req);
799 }
800 
801 /* Do as much copy to/from userspace buffer as we can */
802 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
803 {
804         unsigned ncpy = min(*size, cs->len);
805         if (val) {
806                 void *pgaddr = kmap_atomic(cs->pg);
807                 void *buf = pgaddr + cs->offset;
808 
809                 if (cs->write)
810                         memcpy(buf, *val, ncpy);
811                 else
812                         memcpy(*val, buf, ncpy);
813 
814                 kunmap_atomic(pgaddr);
815                 *val += ncpy;
816         }
817         *size -= ncpy;
818         cs->len -= ncpy;
819         cs->offset += ncpy;
820         return ncpy;
821 }
822 
823 static int fuse_check_page(struct page *page)
824 {
825         if (page_mapcount(page) ||
826             page->mapping != NULL ||
827             page_count(page) != 1 ||
828             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
829              ~(1 << PG_locked |
830                1 << PG_referenced |
831                1 << PG_uptodate |
832                1 << PG_lru |
833                1 << PG_active |
834                1 << PG_reclaim))) {
835                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
836                 printk(KERN_WARNING "  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
837                 return 1;
838         }
839         return 0;
840 }
841 
842 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
843 {
844         int err;
845         struct page *oldpage = *pagep;
846         struct page *newpage;
847         struct pipe_buffer *buf = cs->pipebufs;
848 
849         err = unlock_request(cs->req);
850         if (err)
851                 return err;
852 
853         fuse_copy_finish(cs);
854 
855         err = buf->ops->confirm(cs->pipe, buf);
856         if (err)
857                 return err;
858 
859         BUG_ON(!cs->nr_segs);
860         cs->currbuf = buf;
861         cs->len = buf->len;
862         cs->pipebufs++;
863         cs->nr_segs--;
864 
865         if (cs->len != PAGE_SIZE)
866                 goto out_fallback;
867 
868         if (buf->ops->steal(cs->pipe, buf) != 0)
869                 goto out_fallback;
870 
871         newpage = buf->page;
872 
873         if (!PageUptodate(newpage))
874                 SetPageUptodate(newpage);
875 
876         ClearPageMappedToDisk(newpage);
877 
878         if (fuse_check_page(newpage) != 0)
879                 goto out_fallback_unlock;
880 
881         /*
882          * This is a new and locked page, it shouldn't be mapped or
883          * have any special flags on it
884          */
885         if (WARN_ON(page_mapped(oldpage)))
886                 goto out_fallback_unlock;
887         if (WARN_ON(page_has_private(oldpage)))
888                 goto out_fallback_unlock;
889         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
890                 goto out_fallback_unlock;
891         if (WARN_ON(PageMlocked(oldpage)))
892                 goto out_fallback_unlock;
893 
894         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
895         if (err) {
896                 unlock_page(newpage);
897                 return err;
898         }
899 
900         get_page(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                 put_page(newpage);
916                 return err;
917         }
918 
919         unlock_page(oldpage);
920         put_page(oldpage);
921         cs->len = 0;
922 
923         return 0;
924 
925 out_fallback_unlock:
926         unlock_page(newpage);
927 out_fallback:
928         cs->pg = buf->page;
929         cs->offset = buf->offset;
930 
931         err = lock_request(cs->req);
932         if (err)
933                 return err;
934 
935         return 1;
936 }
937 
938 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
939                          unsigned offset, unsigned count)
940 {
941         struct pipe_buffer *buf;
942         int err;
943 
944         if (cs->nr_segs == cs->pipe->buffers)
945                 return -EIO;
946 
947         err = unlock_request(cs->req);
948         if (err)
949                 return err;
950 
951         fuse_copy_finish(cs);
952 
953         buf = cs->pipebufs;
954         get_page(page);
955         buf->page = page;
956         buf->offset = offset;
957         buf->len = count;
958 
959         cs->pipebufs++;
960         cs->nr_segs++;
961         cs->len = 0;
962 
963         return 0;
964 }
965 
966 /*
967  * Copy a page in the request to/from the userspace buffer.  Must be
968  * done atomically
969  */
970 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
971                           unsigned offset, unsigned count, int zeroing)
972 {
973         int err;
974         struct page *page = *pagep;
975 
976         if (page && zeroing && count < PAGE_SIZE)
977                 clear_highpage(page);
978 
979         while (count) {
980                 if (cs->write && cs->pipebufs && page) {
981                         return fuse_ref_page(cs, page, offset, count);
982                 } else if (!cs->len) {
983                         if (cs->move_pages && page &&
984                             offset == 0 && count == PAGE_SIZE) {
985                                 err = fuse_try_move_page(cs, pagep);
986                                 if (err <= 0)
987                                         return err;
988                         } else {
989                                 err = fuse_copy_fill(cs);
990                                 if (err)
991                                         return err;
992                         }
993                 }
994                 if (page) {
995                         void *mapaddr = kmap_atomic(page);
996                         void *buf = mapaddr + offset;
997                         offset += fuse_copy_do(cs, &buf, &count);
998                         kunmap_atomic(mapaddr);
999                 } else
1000                         offset += fuse_copy_do(cs, NULL, &count);
1001         }
1002         if (page && !cs->write)
1003                 flush_dcache_page(page);
1004         return 0;
1005 }
1006 
1007 /* Copy pages in the request to/from userspace buffer */
1008 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1009                            int zeroing)
1010 {
1011         unsigned i;
1012         struct fuse_req *req = cs->req;
1013 
1014         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1015                 int err;
1016                 unsigned offset = req->page_descs[i].offset;
1017                 unsigned count = min(nbytes, req->page_descs[i].length);
1018 
1019                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1020                                      zeroing);
1021                 if (err)
1022                         return err;
1023 
1024                 nbytes -= count;
1025         }
1026         return 0;
1027 }
1028 
1029 /* Copy a single argument in the request to/from userspace buffer */
1030 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1031 {
1032         while (size) {
1033                 if (!cs->len) {
1034                         int err = fuse_copy_fill(cs);
1035                         if (err)
1036                                 return err;
1037                 }
1038                 fuse_copy_do(cs, &val, &size);
1039         }
1040         return 0;
1041 }
1042 
1043 /* Copy request arguments to/from userspace buffer */
1044 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1045                           unsigned argpages, struct fuse_arg *args,
1046                           int zeroing)
1047 {
1048         int err = 0;
1049         unsigned i;
1050 
1051         for (i = 0; !err && i < numargs; i++)  {
1052                 struct fuse_arg *arg = &args[i];
1053                 if (i == numargs - 1 && argpages)
1054                         err = fuse_copy_pages(cs, arg->size, zeroing);
1055                 else
1056                         err = fuse_copy_one(cs, arg->value, arg->size);
1057         }
1058         return err;
1059 }
1060 
1061 static int forget_pending(struct fuse_iqueue *fiq)
1062 {
1063         return fiq->forget_list_head.next != NULL;
1064 }
1065 
1066 static int request_pending(struct fuse_iqueue *fiq)
1067 {
1068         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1069                 forget_pending(fiq);
1070 }
1071 
1072 /*
1073  * Transfer an interrupt request to userspace
1074  *
1075  * Unlike other requests this is assembled on demand, without a need
1076  * to allocate a separate fuse_req structure.
1077  *
1078  * Called with fiq->waitq.lock held, releases it
1079  */
1080 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1081                                struct fuse_copy_state *cs,
1082                                size_t nbytes, struct fuse_req *req)
1083 __releases(fiq->waitq.lock)
1084 {
1085         struct fuse_in_header ih;
1086         struct fuse_interrupt_in arg;
1087         unsigned reqsize = sizeof(ih) + sizeof(arg);
1088         int err;
1089 
1090         list_del_init(&req->intr_entry);
1091         req->intr_unique = fuse_get_unique(fiq);
1092         memset(&ih, 0, sizeof(ih));
1093         memset(&arg, 0, sizeof(arg));
1094         ih.len = reqsize;
1095         ih.opcode = FUSE_INTERRUPT;
1096         ih.unique = req->intr_unique;
1097         arg.unique = req->in.h.unique;
1098 
1099         spin_unlock(&fiq->waitq.lock);
1100         if (nbytes < reqsize)
1101                 return -EINVAL;
1102 
1103         err = fuse_copy_one(cs, &ih, sizeof(ih));
1104         if (!err)
1105                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1106         fuse_copy_finish(cs);
1107 
1108         return err ? err : reqsize;
1109 }
1110 
1111 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1112                                                unsigned max,
1113                                                unsigned *countp)
1114 {
1115         struct fuse_forget_link *head = fiq->forget_list_head.next;
1116         struct fuse_forget_link **newhead = &head;
1117         unsigned count;
1118 
1119         for (count = 0; *newhead != NULL && count < max; count++)
1120                 newhead = &(*newhead)->next;
1121 
1122         fiq->forget_list_head.next = *newhead;
1123         *newhead = NULL;
1124         if (fiq->forget_list_head.next == NULL)
1125                 fiq->forget_list_tail = &fiq->forget_list_head;
1126 
1127         if (countp != NULL)
1128                 *countp = count;
1129 
1130         return head;
1131 }
1132 
1133 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1134                                    struct fuse_copy_state *cs,
1135                                    size_t nbytes)
1136 __releases(fiq->waitq.lock)
1137 {
1138         int err;
1139         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1140         struct fuse_forget_in arg = {
1141                 .nlookup = forget->forget_one.nlookup,
1142         };
1143         struct fuse_in_header ih = {
1144                 .opcode = FUSE_FORGET,
1145                 .nodeid = forget->forget_one.nodeid,
1146                 .unique = fuse_get_unique(fiq),
1147                 .len = sizeof(ih) + sizeof(arg),
1148         };
1149 
1150         spin_unlock(&fiq->waitq.lock);
1151         kfree(forget);
1152         if (nbytes < ih.len)
1153                 return -EINVAL;
1154 
1155         err = fuse_copy_one(cs, &ih, sizeof(ih));
1156         if (!err)
1157                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1158         fuse_copy_finish(cs);
1159 
1160         if (err)
1161                 return err;
1162 
1163         return ih.len;
1164 }
1165 
1166 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1167                                    struct fuse_copy_state *cs, size_t nbytes)
1168 __releases(fiq->waitq.lock)
1169 {
1170         int err;
1171         unsigned max_forgets;
1172         unsigned count;
1173         struct fuse_forget_link *head;
1174         struct fuse_batch_forget_in arg = { .count = 0 };
1175         struct fuse_in_header ih = {
1176                 .opcode = FUSE_BATCH_FORGET,
1177                 .unique = fuse_get_unique(fiq),
1178                 .len = sizeof(ih) + sizeof(arg),
1179         };
1180 
1181         if (nbytes < ih.len) {
1182                 spin_unlock(&fiq->waitq.lock);
1183                 return -EINVAL;
1184         }
1185 
1186         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1187         head = dequeue_forget(fiq, max_forgets, &count);
1188         spin_unlock(&fiq->waitq.lock);
1189 
1190         arg.count = count;
1191         ih.len += count * sizeof(struct fuse_forget_one);
1192         err = fuse_copy_one(cs, &ih, sizeof(ih));
1193         if (!err)
1194                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1195 
1196         while (head) {
1197                 struct fuse_forget_link *forget = head;
1198 
1199                 if (!err) {
1200                         err = fuse_copy_one(cs, &forget->forget_one,
1201                                             sizeof(forget->forget_one));
1202                 }
1203                 head = forget->next;
1204                 kfree(forget);
1205         }
1206 
1207         fuse_copy_finish(cs);
1208 
1209         if (err)
1210                 return err;
1211 
1212         return ih.len;
1213 }
1214 
1215 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1216                             struct fuse_copy_state *cs,
1217                             size_t nbytes)
1218 __releases(fiq->waitq.lock)
1219 {
1220         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1221                 return fuse_read_single_forget(fiq, cs, nbytes);
1222         else
1223                 return fuse_read_batch_forget(fiq, cs, nbytes);
1224 }
1225 
1226 /*
1227  * Read a single request into the userspace filesystem's buffer.  This
1228  * function waits until a request is available, then removes it from
1229  * the pending list and copies request data to userspace buffer.  If
1230  * no reply is needed (FORGET) or request has been aborted or there
1231  * was an error during the copying then it's finished by calling
1232  * request_end().  Otherwise add it to the processing list, and set
1233  * the 'sent' flag.
1234  */
1235 static ssize_t fuse_dev_do_read(struct fuse_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 
1325 out_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 
1337 static 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 
1348 static 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 
1365 static 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 
1426 out_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 
1436 out:
1437         for (; page_nr < cs.nr_segs; page_nr++)
1438                 put_page(bufs[page_nr].page);
1439 
1440         kfree(bufs);
1441         return ret;
1442 }
1443 
1444 static 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 
1460 err:
1461         fuse_copy_finish(cs);
1462         return err;
1463 }
1464 
1465 static 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 
1488 err:
1489         fuse_copy_finish(cs);
1490         return err;
1491 }
1492 
1493 static 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 
1538 err:
1539         kfree(buf);
1540         fuse_copy_finish(cs);
1541         return err;
1542 }
1543 
1544 static 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 
1590 err:
1591         kfree(buf);
1592         fuse_copy_finish(cs);
1593         return err;
1594 }
1595 
1596 static 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_SHIFT;
1636         offset = outarg.offset & ~PAGE_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_SIZE - offset);
1656                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1657                 if (!err && offset == 0 &&
1658                     (this_num == PAGE_SIZE || file_size == end))
1659                         SetPageUptodate(page);
1660                 unlock_page(page);
1661                 put_page(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 
1673 out_iput:
1674         iput(inode);
1675 out_up_killsb:
1676         up_read(&fc->killsb);
1677 out_finish:
1678         fuse_copy_finish(cs);
1679         return err;
1680 }
1681 
1682 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1683 {
1684         release_pages(req->pages, req->num_pages, false);
1685 }
1686 
1687 static 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_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_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_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 
1756 static 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 
1788 copy_finish:
1789         fuse_copy_finish(cs);
1790         return err;
1791 }
1792 
1793 static 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 */
1825 static 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 
1836 static 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  */
1866 static 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 
1958 static 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 
1974 static 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         }
2048 out:
2049         kfree(bufs);
2050         return ret;
2051 }
2052 
2053 static 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  */
2080 static 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 
2093 static 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  */
2126 void 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 }
2184 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2185 
2186 int 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 }
2205 EXPORT_SYMBOL_GPL(fuse_dev_release);
2206 
2207 static 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 
2218 static 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 
2235 static 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 
2271 const 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 };
2285 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2286 
2287 static struct miscdevice fuse_miscdevice = {
2288         .minor = FUSE_MINOR,
2289         .name  = "fuse",
2290         .fops = &fuse_dev_operations,
2291 };
2292 
2293 int __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 
2314 void fuse_dev_cleanup(void)
2315 {
2316         misc_deregister(&fuse_miscdevice);
2317         kmem_cache_destroy(fuse_req_cachep);
2318 }
2319 

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