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Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / fs / fuse / dev.c
blob5f3368ab0fa9d44ff8b5121db33d158ef5989da9
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/uio.h>
15 #include <linux/miscdevice.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/slab.h>
19 #include <linux/pipe_fs_i.h>
20 #include <linux/swap.h>
21 #include <linux/splice.h>
22
23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
24 MODULE_ALIAS("devname:fuse");
25
26 static struct kmem_cache *fuse_req_cachep;
27
28 static struct fuse_conn *fuse_get_conn(struct file *file)
29 {
30 /*
31 * Lockless access is OK, because file->private data is set
32 * once during mount and is valid until the file is released.
33 */
34 return file->private_data;
35 }
36
37 static void fuse_request_init(struct fuse_req *req)
38 {
39 memset(req, 0, sizeof(*req));
40 INIT_LIST_HEAD(&req->list);
41 INIT_LIST_HEAD(&req->intr_entry);
42 init_waitqueue_head(&req->waitq);
43 atomic_set(&req->count, 1);
44 }
45
46 struct fuse_req *fuse_request_alloc(void)
47 {
48 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
49 if (req)
50 fuse_request_init(req);
51 return req;
52 }
53 EXPORT_SYMBOL_GPL(fuse_request_alloc);
54
55 struct fuse_req *fuse_request_alloc_nofs(void)
56 {
57 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
58 if (req)
59 fuse_request_init(req);
60 return req;
61 }
62
63 void fuse_request_free(struct fuse_req *req)
64 {
65 kmem_cache_free(fuse_req_cachep, req);
66 }
67
68 static void block_sigs(sigset_t *oldset)
69 {
70 sigset_t mask;
71
72 siginitsetinv(&mask, sigmask(SIGKILL));
73 sigprocmask(SIG_BLOCK, &mask, oldset);
74 }
75
76 static void restore_sigs(sigset_t *oldset)
77 {
78 sigprocmask(SIG_SETMASK, oldset, NULL);
79 }
80
81 static void __fuse_get_request(struct fuse_req *req)
82 {
83 atomic_inc(&req->count);
84 }
85
86 /* Must be called with > 1 refcount */
87 static void __fuse_put_request(struct fuse_req *req)
88 {
89 BUG_ON(atomic_read(&req->count) < 2);
90 atomic_dec(&req->count);
91 }
92
93 static void fuse_req_init_context(struct fuse_req *req)
94 {
95 req->in.h.uid = current_fsuid();
96 req->in.h.gid = current_fsgid();
97 req->in.h.pid = current->pid;
98 }
99
100 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
101 {
102 struct fuse_req *req;
103 sigset_t oldset;
104 int intr;
105 int err;
106
107 atomic_inc(&fc->num_waiting);
108 block_sigs(&oldset);
109 intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
110 restore_sigs(&oldset);
111 err = -EINTR;
112 if (intr)
113 goto out;
114
115 err = -ENOTCONN;
116 if (!fc->connected)
117 goto out;
118
119 req = fuse_request_alloc();
120 err = -ENOMEM;
121 if (!req)
122 goto out;
123
124 fuse_req_init_context(req);
125 req->waiting = 1;
126 return req;
127
128 out:
129 atomic_dec(&fc->num_waiting);
130 return ERR_PTR(err);
131 }
132 EXPORT_SYMBOL_GPL(fuse_get_req);
133
134 /*
135 * Return request in fuse_file->reserved_req. However that may
136 * currently be in use. If that is the case, wait for it to become
137 * available.
138 */
139 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
140 struct file *file)
141 {
142 struct fuse_req *req = NULL;
143 struct fuse_file *ff = file->private_data;
144
145 do {
146 wait_event(fc->reserved_req_waitq, ff->reserved_req);
147 spin_lock(&fc->lock);
148 if (ff->reserved_req) {
149 req = ff->reserved_req;
150 ff->reserved_req = NULL;
151 get_file(file);
152 req->stolen_file = file;
153 }
154 spin_unlock(&fc->lock);
155 } while (!req);
156
157 return req;
158 }
159
160 /*
161 * Put stolen request back into fuse_file->reserved_req
162 */
163 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
164 {
165 struct file *file = req->stolen_file;
166 struct fuse_file *ff = file->private_data;
167
168 spin_lock(&fc->lock);
169 fuse_request_init(req);
170 BUG_ON(ff->reserved_req);
171 ff->reserved_req = req;
172 wake_up_all(&fc->reserved_req_waitq);
173 spin_unlock(&fc->lock);
174 fput(file);
175 }
176
177 /*
178 * Gets a requests for a file operation, always succeeds
179 *
180 * This is used for sending the FLUSH request, which must get to
181 * userspace, due to POSIX locks which may need to be unlocked.
182 *
183 * If allocation fails due to OOM, use the reserved request in
184 * fuse_file.
185 *
186 * This is very unlikely to deadlock accidentally, since the
187 * filesystem should not have it's own file open. If deadlock is
188 * intentional, it can still be broken by "aborting" the filesystem.
189 */
190 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
191 {
192 struct fuse_req *req;
193
194 atomic_inc(&fc->num_waiting);
195 wait_event(fc->blocked_waitq, !fc->blocked);
196 req = fuse_request_alloc();
197 if (!req)
198 req = get_reserved_req(fc, file);
199
200 fuse_req_init_context(req);
201 req->waiting = 1;
202 return req;
203 }
204
205 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
206 {
207 if (atomic_dec_and_test(&req->count)) {
208 if (req->waiting)
209 atomic_dec(&fc->num_waiting);
210
211 if (req->stolen_file)
212 put_reserved_req(fc, req);
213 else
214 fuse_request_free(req);
215 }
216 }
217 EXPORT_SYMBOL_GPL(fuse_put_request);
218
219 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
220 {
221 unsigned nbytes = 0;
222 unsigned i;
223
224 for (i = 0; i < numargs; i++)
225 nbytes += args[i].size;
226
227 return nbytes;
228 }
229
230 static u64 fuse_get_unique(struct fuse_conn *fc)
231 {
232 fc->reqctr++;
233 /* zero is special */
234 if (fc->reqctr == 0)
235 fc->reqctr = 1;
236
237 return fc->reqctr;
238 }
239
240 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
241 {
242 req->in.h.len = sizeof(struct fuse_in_header) +
243 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
244 list_add_tail(&req->list, &fc->pending);
245 req->state = FUSE_REQ_PENDING;
246 if (!req->waiting) {
247 req->waiting = 1;
248 atomic_inc(&fc->num_waiting);
249 }
250 wake_up(&fc->waitq);
251 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
252 }
253
254 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
255 u64 nodeid, u64 nlookup)
256 {
257 forget->forget_one.nodeid = nodeid;
258 forget->forget_one.nlookup = nlookup;
259
260 spin_lock(&fc->lock);
261 if (fc->connected) {
262 fc->forget_list_tail->next = forget;
263 fc->forget_list_tail = forget;
264 wake_up(&fc->waitq);
265 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
266 } else {
267 kfree(forget);
268 }
269 spin_unlock(&fc->lock);
270 }
271
272 static void flush_bg_queue(struct fuse_conn *fc)
273 {
274 while (fc->active_background < fc->max_background &&
275 !list_empty(&fc->bg_queue)) {
276 struct fuse_req *req;
277
278 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
279 list_del(&req->list);
280 fc->active_background++;
281 req->in.h.unique = fuse_get_unique(fc);
282 queue_request(fc, req);
283 }
284 }
285
286 /*
287 * This function is called when a request is finished. Either a reply
288 * has arrived or it was aborted (and not yet sent) or some error
289 * occurred during communication with userspace, or the device file
290 * was closed. The requester thread is woken up (if still waiting),
291 * the 'end' callback is called if given, else the reference to the
292 * request is released
293 *
294 * Called with fc->lock, unlocks it
295 */
296 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
297 __releases(fc->lock)
298 {
299 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
300 req->end = NULL;
301 list_del(&req->list);
302 list_del(&req->intr_entry);
303 req->state = FUSE_REQ_FINISHED;
304 if (req->background) {
305 if (fc->num_background == fc->max_background) {
306 fc->blocked = 0;
307 wake_up_all(&fc->blocked_waitq);
308 }
309 if (fc->num_background == fc->congestion_threshold &&
310 fc->connected && fc->bdi_initialized) {
311 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
312 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
313 }
314 fc->num_background--;
315 fc->active_background--;
316 flush_bg_queue(fc);
317 }
318 spin_unlock(&fc->lock);
319 wake_up(&req->waitq);
320 if (end)
321 end(fc, req);
322 fuse_put_request(fc, req);
323 }
324
325 static void wait_answer_interruptible(struct fuse_conn *fc,
326 struct fuse_req *req)
327 __releases(fc->lock)
328 __acquires(fc->lock)
329 {
330 if (signal_pending(current))
331 return;
332
333 spin_unlock(&fc->lock);
334 wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
335 spin_lock(&fc->lock);
336 }
337
338 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
339 {
340 list_add_tail(&req->intr_entry, &fc->interrupts);
341 wake_up(&fc->waitq);
342 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
343 }
344
345 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
346 __releases(fc->lock)
347 __acquires(fc->lock)
348 {
349 if (!fc->no_interrupt) {
350 /* Any signal may interrupt this */
351 wait_answer_interruptible(fc, req);
352
353 if (req->aborted)
354 goto aborted;
355 if (req->state == FUSE_REQ_FINISHED)
356 return;
357
358 req->interrupted = 1;
359 if (req->state == FUSE_REQ_SENT)
360 queue_interrupt(fc, req);
361 }
362
363 if (!req->force) {
364 sigset_t oldset;
365
366 /* Only fatal signals may interrupt this */
367 block_sigs(&oldset);
368 wait_answer_interruptible(fc, req);
369 restore_sigs(&oldset);
370
371 if (req->aborted)
372 goto aborted;
373 if (req->state == FUSE_REQ_FINISHED)
374 return;
375
376 /* Request is not yet in userspace, bail out */
377 if (req->state == FUSE_REQ_PENDING) {
378 list_del(&req->list);
379 __fuse_put_request(req);
380 req->out.h.error = -EINTR;
381 return;
382 }
383 }
384
385 /*
386 * Either request is already in userspace, or it was forced.
387 * Wait it out.
388 */
389 spin_unlock(&fc->lock);
390 wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
391 spin_lock(&fc->lock);
392
393 if (!req->aborted)
394 return;
395
396 aborted:
397 BUG_ON(req->state != FUSE_REQ_FINISHED);
398 if (req->locked) {
399 /* This is uninterruptible sleep, because data is
400 being copied to/from the buffers of req. During
401 locked state, there mustn't be any filesystem
402 operation (e.g. page fault), since that could lead
403 to deadlock */
404 spin_unlock(&fc->lock);
405 wait_event(req->waitq, !req->locked);
406 spin_lock(&fc->lock);
407 }
408 }
409
410 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
411 {
412 req->isreply = 1;
413 spin_lock(&fc->lock);
414 if (!fc->connected)
415 req->out.h.error = -ENOTCONN;
416 else if (fc->conn_error)
417 req->out.h.error = -ECONNREFUSED;
418 else {
419 req->in.h.unique = fuse_get_unique(fc);
420 queue_request(fc, req);
421 /* acquire extra reference, since request is still needed
422 after request_end() */
423 __fuse_get_request(req);
424
425 request_wait_answer(fc, req);
426 }
427 spin_unlock(&fc->lock);
428 }
429 EXPORT_SYMBOL_GPL(fuse_request_send);
430
431 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
432 struct fuse_req *req)
433 {
434 req->background = 1;
435 fc->num_background++;
436 if (fc->num_background == fc->max_background)
437 fc->blocked = 1;
438 if (fc->num_background == fc->congestion_threshold &&
439 fc->bdi_initialized) {
440 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
441 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
442 }
443 list_add_tail(&req->list, &fc->bg_queue);
444 flush_bg_queue(fc);
445 }
446
447 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
448 {
449 spin_lock(&fc->lock);
450 if (fc->connected) {
451 fuse_request_send_nowait_locked(fc, req);
452 spin_unlock(&fc->lock);
453 } else {
454 req->out.h.error = -ENOTCONN;
455 request_end(fc, req);
456 }
457 }
458
459 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
460 {
461 req->isreply = 1;
462 fuse_request_send_nowait(fc, req);
463 }
464 EXPORT_SYMBOL_GPL(fuse_request_send_background);
465
466 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
467 struct fuse_req *req, u64 unique)
468 {
469 int err = -ENODEV;
470
471 req->isreply = 0;
472 req->in.h.unique = unique;
473 spin_lock(&fc->lock);
474 if (fc->connected) {
475 queue_request(fc, req);
476 err = 0;
477 }
478 spin_unlock(&fc->lock);
479
480 return err;
481 }
482
483 /*
484 * Called under fc->lock
485 *
486 * fc->connected must have been checked previously
487 */
488 void fuse_request_send_background_locked(struct fuse_conn *fc,
489 struct fuse_req *req)
490 {
491 req->isreply = 1;
492 fuse_request_send_nowait_locked(fc, req);
493 }
494
495 /*
496 * Lock the request. Up to the next unlock_request() there mustn't be
497 * anything that could cause a page-fault. If the request was already
498 * aborted bail out.
499 */
500 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
501 {
502 int err = 0;
503 if (req) {
504 spin_lock(&fc->lock);
505 if (req->aborted)
506 err = -ENOENT;
507 else
508 req->locked = 1;
509 spin_unlock(&fc->lock);
510 }
511 return err;
512 }
513
514 /*
515 * Unlock request. If it was aborted during being locked, the
516 * requester thread is currently waiting for it to be unlocked, so
517 * wake it up.
518 */
519 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
520 {
521 if (req) {
522 spin_lock(&fc->lock);
523 req->locked = 0;
524 if (req->aborted)
525 wake_up(&req->waitq);
526 spin_unlock(&fc->lock);
527 }
528 }
529
530 struct fuse_copy_state {
531 struct fuse_conn *fc;
532 int write;
533 struct fuse_req *req;
534 const struct iovec *iov;
535 struct pipe_buffer *pipebufs;
536 struct pipe_buffer *currbuf;
537 struct pipe_inode_info *pipe;
538 unsigned long nr_segs;
539 unsigned long seglen;
540 unsigned long addr;
541 struct page *pg;
542 void *mapaddr;
543 void *buf;
544 unsigned len;
545 unsigned move_pages:1;
546 };
547
548 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
549 int write,
550 const struct iovec *iov, unsigned long nr_segs)
551 {
552 memset(cs, 0, sizeof(*cs));
553 cs->fc = fc;
554 cs->write = write;
555 cs->iov = iov;
556 cs->nr_segs = nr_segs;
557 }
558
559 /* Unmap and put previous page of userspace buffer */
560 static void fuse_copy_finish(struct fuse_copy_state *cs)
561 {
562 if (cs->currbuf) {
563 struct pipe_buffer *buf = cs->currbuf;
564
565 if (!cs->write) {
566 buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
567 } else {
568 kunmap(buf->page);
569 buf->len = PAGE_SIZE - cs->len;
570 }
571 cs->currbuf = NULL;
572 cs->mapaddr = NULL;
573 } else if (cs->mapaddr) {
574 kunmap(cs->pg);
575 if (cs->write) {
576 flush_dcache_page(cs->pg);
577 set_page_dirty_lock(cs->pg);
578 }
579 put_page(cs->pg);
580 cs->mapaddr = NULL;
581 }
582 }
583
584 /*
585 * Get another pagefull of userspace buffer, and map it to kernel
586 * address space, and lock request
587 */
588 static int fuse_copy_fill(struct fuse_copy_state *cs)
589 {
590 unsigned long offset;
591 int err;
592
593 unlock_request(cs->fc, cs->req);
594 fuse_copy_finish(cs);
595 if (cs->pipebufs) {
596 struct pipe_buffer *buf = cs->pipebufs;
597
598 if (!cs->write) {
599 err = buf->ops->confirm(cs->pipe, buf);
600 if (err)
601 return err;
602
603 BUG_ON(!cs->nr_segs);
604 cs->currbuf = buf;
605 cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
606 cs->len = buf->len;
607 cs->buf = cs->mapaddr + buf->offset;
608 cs->pipebufs++;
609 cs->nr_segs--;
610 } else {
611 struct page *page;
612
613 if (cs->nr_segs == cs->pipe->buffers)
614 return -EIO;
615
616 page = alloc_page(GFP_HIGHUSER);
617 if (!page)
618 return -ENOMEM;
619
620 buf->page = page;
621 buf->offset = 0;
622 buf->len = 0;
623
624 cs->currbuf = buf;
625 cs->mapaddr = kmap(page);
626 cs->buf = cs->mapaddr;
627 cs->len = PAGE_SIZE;
628 cs->pipebufs++;
629 cs->nr_segs++;
630 }
631 } else {
632 if (!cs->seglen) {
633 BUG_ON(!cs->nr_segs);
634 cs->seglen = cs->iov[0].iov_len;
635 cs->addr = (unsigned long) cs->iov[0].iov_base;
636 cs->iov++;
637 cs->nr_segs--;
638 }
639 err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
640 if (err < 0)
641 return err;
642 BUG_ON(err != 1);
643 offset = cs->addr % PAGE_SIZE;
644 cs->mapaddr = kmap(cs->pg);
645 cs->buf = cs->mapaddr + offset;
646 cs->len = min(PAGE_SIZE - offset, cs->seglen);
647 cs->seglen -= cs->len;
648 cs->addr += cs->len;
649 }
650
651 return lock_request(cs->fc, cs->req);
652 }
653
654 /* Do as much copy to/from userspace buffer as we can */
655 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
656 {
657 unsigned ncpy = min(*size, cs->len);
658 if (val) {
659 if (cs->write)
660 memcpy(cs->buf, *val, ncpy);
661 else
662 memcpy(*val, cs->buf, ncpy);
663 *val += ncpy;
664 }
665 *size -= ncpy;
666 cs->len -= ncpy;
667 cs->buf += ncpy;
668 return ncpy;
669 }
670
671 static int fuse_check_page(struct page *page)
672 {
673 if (page_mapcount(page) ||
674 page->mapping != NULL ||
675 page_count(page) != 1 ||
676 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
677 ~(1 << PG_locked |
678 1 << PG_referenced |
679 1 << PG_uptodate |
680 1 << PG_lru |
681 1 << PG_active |
682 1 << PG_reclaim))) {
683 printk(KERN_WARNING "fuse: trying to steal weird page\n");
684 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);
685 return 1;
686 }
687 return 0;
688 }
689
690 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
691 {
692 int err;
693 struct page *oldpage = *pagep;
694 struct page *newpage;
695 struct pipe_buffer *buf = cs->pipebufs;
696 struct address_space *mapping;
697 pgoff_t index;
698
699 unlock_request(cs->fc, cs->req);
700 fuse_copy_finish(cs);
701
702 err = buf->ops->confirm(cs->pipe, buf);
703 if (err)
704 return err;
705
706 BUG_ON(!cs->nr_segs);
707 cs->currbuf = buf;
708 cs->len = buf->len;
709 cs->pipebufs++;
710 cs->nr_segs--;
711
712 if (cs->len != PAGE_SIZE)
713 goto out_fallback;
714
715 if (buf->ops->steal(cs->pipe, buf) != 0)
716 goto out_fallback;
717
718 newpage = buf->page;
719
720 if (WARN_ON(!PageUptodate(newpage)))
721 return -EIO;
722
723 ClearPageMappedToDisk(newpage);
724
725 if (fuse_check_page(newpage) != 0)
726 goto out_fallback_unlock;
727
728 mapping = oldpage->mapping;
729 index = oldpage->index;
730
731 /*
732 * This is a new and locked page, it shouldn't be mapped or
733 * have any special flags on it
734 */
735 if (WARN_ON(page_mapped(oldpage)))
736 goto out_fallback_unlock;
737 if (WARN_ON(page_has_private(oldpage)))
738 goto out_fallback_unlock;
739 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
740 goto out_fallback_unlock;
741 if (WARN_ON(PageMlocked(oldpage)))
742 goto out_fallback_unlock;
743
744 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
745 if (err) {
746 unlock_page(newpage);
747 return err;
748 }
749
750 page_cache_get(newpage);
751
752 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
753 lru_cache_add_file(newpage);
754
755 err = 0;
756 spin_lock(&cs->fc->lock);
757 if (cs->req->aborted)
758 err = -ENOENT;
759 else
760 *pagep = newpage;
761 spin_unlock(&cs->fc->lock);
762
763 if (err) {
764 unlock_page(newpage);
765 page_cache_release(newpage);
766 return err;
767 }
768
769 unlock_page(oldpage);
770 page_cache_release(oldpage);
771 cs->len = 0;
772
773 return 0;
774
775 out_fallback_unlock:
776 unlock_page(newpage);
777 out_fallback:
778 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
779 cs->buf = cs->mapaddr + buf->offset;
780
781 err = lock_request(cs->fc, cs->req);
782 if (err)
783 return err;
784
785 return 1;
786 }
787
788 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
789 unsigned offset, unsigned count)
790 {
791 struct pipe_buffer *buf;
792
793 if (cs->nr_segs == cs->pipe->buffers)
794 return -EIO;
795
796 unlock_request(cs->fc, cs->req);
797 fuse_copy_finish(cs);
798
799 buf = cs->pipebufs;
800 page_cache_get(page);
801 buf->page = page;
802 buf->offset = offset;
803 buf->len = count;
804
805 cs->pipebufs++;
806 cs->nr_segs++;
807 cs->len = 0;
808
809 return 0;
810 }
811
812 /*
813 * Copy a page in the request to/from the userspace buffer. Must be
814 * done atomically
815 */
816 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
817 unsigned offset, unsigned count, int zeroing)
818 {
819 int err;
820 struct page *page = *pagep;
821
822 if (page && zeroing && count < PAGE_SIZE)
823 clear_highpage(page);
824
825 while (count) {
826 if (cs->write && cs->pipebufs && page) {
827 return fuse_ref_page(cs, page, offset, count);
828 } else if (!cs->len) {
829 if (cs->move_pages && page &&
830 offset == 0 && count == PAGE_SIZE) {
831 err = fuse_try_move_page(cs, pagep);
832 if (err <= 0)
833 return err;
834 } else {
835 err = fuse_copy_fill(cs);
836 if (err)
837 return err;
838 }
839 }
840 if (page) {
841 void *mapaddr = kmap_atomic(page, KM_USER0);
842 void *buf = mapaddr + offset;
843 offset += fuse_copy_do(cs, &buf, &count);
844 kunmap_atomic(mapaddr, KM_USER0);
845 } else
846 offset += fuse_copy_do(cs, NULL, &count);
847 }
848 if (page && !cs->write)
849 flush_dcache_page(page);
850 return 0;
851 }
852
853 /* Copy pages in the request to/from userspace buffer */
854 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
855 int zeroing)
856 {
857 unsigned i;
858 struct fuse_req *req = cs->req;
859 unsigned offset = req->page_offset;
860 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
861
862 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
863 int err;
864
865 err = fuse_copy_page(cs, &req->pages[i], offset, count,
866 zeroing);
867 if (err)
868 return err;
869
870 nbytes -= count;
871 count = min(nbytes, (unsigned) PAGE_SIZE);
872 offset = 0;
873 }
874 return 0;
875 }
876
877 /* Copy a single argument in the request to/from userspace buffer */
878 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
879 {
880 while (size) {
881 if (!cs->len) {
882 int err = fuse_copy_fill(cs);
883 if (err)
884 return err;
885 }
886 fuse_copy_do(cs, &val, &size);
887 }
888 return 0;
889 }
890
891 /* Copy request arguments to/from userspace buffer */
892 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
893 unsigned argpages, struct fuse_arg *args,
894 int zeroing)
895 {
896 int err = 0;
897 unsigned i;
898
899 for (i = 0; !err && i < numargs; i++) {
900 struct fuse_arg *arg = &args[i];
901 if (i == numargs - 1 && argpages)
902 err = fuse_copy_pages(cs, arg->size, zeroing);
903 else
904 err = fuse_copy_one(cs, arg->value, arg->size);
905 }
906 return err;
907 }
908
909 static int forget_pending(struct fuse_conn *fc)
910 {
911 return fc->forget_list_head.next != NULL;
912 }
913
914 static int request_pending(struct fuse_conn *fc)
915 {
916 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
917 forget_pending(fc);
918 }
919
920 /* Wait until a request is available on the pending list */
921 static void request_wait(struct fuse_conn *fc)
922 __releases(fc->lock)
923 __acquires(fc->lock)
924 {
925 DECLARE_WAITQUEUE(wait, current);
926
927 add_wait_queue_exclusive(&fc->waitq, &wait);
928 while (fc->connected && !request_pending(fc)) {
929 set_current_state(TASK_INTERRUPTIBLE);
930 if (signal_pending(current))
931 break;
932
933 spin_unlock(&fc->lock);
934 schedule();
935 spin_lock(&fc->lock);
936 }
937 set_current_state(TASK_RUNNING);
938 remove_wait_queue(&fc->waitq, &wait);
939 }
940
941 /*
942 * Transfer an interrupt request to userspace
943 *
944 * Unlike other requests this is assembled on demand, without a need
945 * to allocate a separate fuse_req structure.
946 *
947 * Called with fc->lock held, releases it
948 */
949 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
950 size_t nbytes, struct fuse_req *req)
951 __releases(fc->lock)
952 {
953 struct fuse_in_header ih;
954 struct fuse_interrupt_in arg;
955 unsigned reqsize = sizeof(ih) + sizeof(arg);
956 int err;
957
958 list_del_init(&req->intr_entry);
959 req->intr_unique = fuse_get_unique(fc);
960 memset(&ih, 0, sizeof(ih));
961 memset(&arg, 0, sizeof(arg));
962 ih.len = reqsize;
963 ih.opcode = FUSE_INTERRUPT;
964 ih.unique = req->intr_unique;
965 arg.unique = req->in.h.unique;
966
967 spin_unlock(&fc->lock);
968 if (nbytes < reqsize)
969 return -EINVAL;
970
971 err = fuse_copy_one(cs, &ih, sizeof(ih));
972 if (!err)
973 err = fuse_copy_one(cs, &arg, sizeof(arg));
974 fuse_copy_finish(cs);
975
976 return err ? err : reqsize;
977 }
978
979 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
980 unsigned max,
981 unsigned *countp)
982 {
983 struct fuse_forget_link *head = fc->forget_list_head.next;
984 struct fuse_forget_link **newhead = &head;
985 unsigned count;
986
987 for (count = 0; *newhead != NULL && count < max; count++)
988 newhead = &(*newhead)->next;
989
990 fc->forget_list_head.next = *newhead;
991 *newhead = NULL;
992 if (fc->forget_list_head.next == NULL)
993 fc->forget_list_tail = &fc->forget_list_head;
994
995 if (countp != NULL)
996 *countp = count;
997
998 return head;
999 }
1000
1001 static int fuse_read_single_forget(struct fuse_conn *fc,
1002 struct fuse_copy_state *cs,
1003 size_t nbytes)
1004 __releases(fc->lock)
1005 {
1006 int err;
1007 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1008 struct fuse_forget_in arg = {
1009 .nlookup = forget->forget_one.nlookup,
1010 };
1011 struct fuse_in_header ih = {
1012 .opcode = FUSE_FORGET,
1013 .nodeid = forget->forget_one.nodeid,
1014 .unique = fuse_get_unique(fc),
1015 .len = sizeof(ih) + sizeof(arg),
1016 };
1017
1018 spin_unlock(&fc->lock);
1019 kfree(forget);
1020 if (nbytes < ih.len)
1021 return -EINVAL;
1022
1023 err = fuse_copy_one(cs, &ih, sizeof(ih));
1024 if (!err)
1025 err = fuse_copy_one(cs, &arg, sizeof(arg));
1026 fuse_copy_finish(cs);
1027
1028 if (err)
1029 return err;
1030
1031 return ih.len;
1032 }
1033
1034 static int fuse_read_batch_forget(struct fuse_conn *fc,
1035 struct fuse_copy_state *cs, size_t nbytes)
1036 __releases(fc->lock)
1037 {
1038 int err;
1039 unsigned max_forgets;
1040 unsigned count;
1041 struct fuse_forget_link *head;
1042 struct fuse_batch_forget_in arg = { .count = 0 };
1043 struct fuse_in_header ih = {
1044 .opcode = FUSE_BATCH_FORGET,
1045 .unique = fuse_get_unique(fc),
1046 .len = sizeof(ih) + sizeof(arg),
1047 };
1048
1049 if (nbytes < ih.len) {
1050 spin_unlock(&fc->lock);
1051 return -EINVAL;
1052 }
1053
1054 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1055 head = dequeue_forget(fc, max_forgets, &count);
1056 spin_unlock(&fc->lock);
1057
1058 arg.count = count;
1059 ih.len += count * sizeof(struct fuse_forget_one);
1060 err = fuse_copy_one(cs, &ih, sizeof(ih));
1061 if (!err)
1062 err = fuse_copy_one(cs, &arg, sizeof(arg));
1063
1064 while (head) {
1065 struct fuse_forget_link *forget = head;
1066
1067 if (!err) {
1068 err = fuse_copy_one(cs, &forget->forget_one,
1069 sizeof(forget->forget_one));
1070 }
1071 head = forget->next;
1072 kfree(forget);
1073 }
1074
1075 fuse_copy_finish(cs);
1076
1077 if (err)
1078 return err;
1079
1080 return ih.len;
1081 }
1082
1083 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1084 size_t nbytes)
1085 __releases(fc->lock)
1086 {
1087 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1088 return fuse_read_single_forget(fc, cs, nbytes);
1089 else
1090 return fuse_read_batch_forget(fc, cs, nbytes);
1091 }
1092
1093 /*
1094 * Read a single request into the userspace filesystem's buffer. This
1095 * function waits until a request is available, then removes it from
1096 * the pending list and copies request data to userspace buffer. If
1097 * no reply is needed (FORGET) or request has been aborted or there
1098 * was an error during the copying then it's finished by calling
1099 * request_end(). Otherwise add it to the processing list, and set
1100 * the 'sent' flag.
1101 */
1102 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1103 struct fuse_copy_state *cs, size_t nbytes)
1104 {
1105 int err;
1106 struct fuse_req *req;
1107 struct fuse_in *in;
1108 unsigned reqsize;
1109
1110 restart:
1111 spin_lock(&fc->lock);
1112 err = -EAGAIN;
1113 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1114 !request_pending(fc))
1115 goto err_unlock;
1116
1117 request_wait(fc);
1118 err = -ENODEV;
1119 if (!fc->connected)
1120 goto err_unlock;
1121 err = -ERESTARTSYS;
1122 if (!request_pending(fc))
1123 goto err_unlock;
1124
1125 if (!list_empty(&fc->interrupts)) {
1126 req = list_entry(fc->interrupts.next, struct fuse_req,
1127 intr_entry);
1128 return fuse_read_interrupt(fc, cs, nbytes, req);
1129 }
1130
1131 if (forget_pending(fc)) {
1132 if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1133 return fuse_read_forget(fc, cs, nbytes);
1134
1135 if (fc->forget_batch <= -8)
1136 fc->forget_batch = 16;
1137 }
1138
1139 req = list_entry(fc->pending.next, struct fuse_req, list);
1140 req->state = FUSE_REQ_READING;
1141 list_move(&req->list, &fc->io);
1142
1143 in = &req->in;
1144 reqsize = in->h.len;
1145 /* If request is too large, reply with an error and restart the read */
1146 if (nbytes < reqsize) {
1147 req->out.h.error = -EIO;
1148 /* SETXATTR is special, since it may contain too large data */
1149 if (in->h.opcode == FUSE_SETXATTR)
1150 req->out.h.error = -E2BIG;
1151 request_end(fc, req);
1152 goto restart;
1153 }
1154 spin_unlock(&fc->lock);
1155 cs->req = req;
1156 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1157 if (!err)
1158 err = fuse_copy_args(cs, in->numargs, in->argpages,
1159 (struct fuse_arg *) in->args, 0);
1160 fuse_copy_finish(cs);
1161 spin_lock(&fc->lock);
1162 req->locked = 0;
1163 if (req->aborted) {
1164 request_end(fc, req);
1165 return -ENODEV;
1166 }
1167 if (err) {
1168 req->out.h.error = -EIO;
1169 request_end(fc, req);
1170 return err;
1171 }
1172 if (!req->isreply)
1173 request_end(fc, req);
1174 else {
1175 req->state = FUSE_REQ_SENT;
1176 list_move_tail(&req->list, &fc->processing);
1177 if (req->interrupted)
1178 queue_interrupt(fc, req);
1179 spin_unlock(&fc->lock);
1180 }
1181 return reqsize;
1182
1183 err_unlock:
1184 spin_unlock(&fc->lock);
1185 return err;
1186 }
1187
1188 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1189 unsigned long nr_segs, loff_t pos)
1190 {
1191 struct fuse_copy_state cs;
1192 struct file *file = iocb->ki_filp;
1193 struct fuse_conn *fc = fuse_get_conn(file);
1194 if (!fc)
1195 return -EPERM;
1196
1197 fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1198
1199 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1200 }
1201
1202 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1203 struct pipe_buffer *buf)
1204 {
1205 return 1;
1206 }
1207
1208 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1209 .can_merge = 0,
1210 .map = generic_pipe_buf_map,
1211 .unmap = generic_pipe_buf_unmap,
1212 .confirm = generic_pipe_buf_confirm,
1213 .release = generic_pipe_buf_release,
1214 .steal = fuse_dev_pipe_buf_steal,
1215 .get = generic_pipe_buf_get,
1216 };
1217
1218 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1219 struct pipe_inode_info *pipe,
1220 size_t len, unsigned int flags)
1221 {
1222 int ret;
1223 int page_nr = 0;
1224 int do_wakeup = 0;
1225 struct pipe_buffer *bufs;
1226 struct fuse_copy_state cs;
1227 struct fuse_conn *fc = fuse_get_conn(in);
1228 if (!fc)
1229 return -EPERM;
1230
1231 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1232 if (!bufs)
1233 return -ENOMEM;
1234
1235 fuse_copy_init(&cs, fc, 1, NULL, 0);
1236 cs.pipebufs = bufs;
1237 cs.pipe = pipe;
1238 ret = fuse_dev_do_read(fc, in, &cs, len);
1239 if (ret < 0)
1240 goto out;
1241
1242 ret = 0;
1243 pipe_lock(pipe);
1244
1245 if (!pipe->readers) {
1246 send_sig(SIGPIPE, current, 0);
1247 if (!ret)
1248 ret = -EPIPE;
1249 goto out_unlock;
1250 }
1251
1252 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1253 ret = -EIO;
1254 goto out_unlock;
1255 }
1256
1257 while (page_nr < cs.nr_segs) {
1258 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1259 struct pipe_buffer *buf = pipe->bufs + newbuf;
1260
1261 buf->page = bufs[page_nr].page;
1262 buf->offset = bufs[page_nr].offset;
1263 buf->len = bufs[page_nr].len;
1264 buf->ops = &fuse_dev_pipe_buf_ops;
1265
1266 pipe->nrbufs++;
1267 page_nr++;
1268 ret += buf->len;
1269
1270 if (pipe->inode)
1271 do_wakeup = 1;
1272 }
1273
1274 out_unlock:
1275 pipe_unlock(pipe);
1276
1277 if (do_wakeup) {
1278 smp_mb();
1279 if (waitqueue_active(&pipe->wait))
1280 wake_up_interruptible(&pipe->wait);
1281 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1282 }
1283
1284 out:
1285 for (; page_nr < cs.nr_segs; page_nr++)
1286 page_cache_release(bufs[page_nr].page);
1287
1288 kfree(bufs);
1289 return ret;
1290 }
1291
1292 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1293 struct fuse_copy_state *cs)
1294 {
1295 struct fuse_notify_poll_wakeup_out outarg;
1296 int err = -EINVAL;
1297
1298 if (size != sizeof(outarg))
1299 goto err;
1300
1301 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1302 if (err)
1303 goto err;
1304
1305 fuse_copy_finish(cs);
1306 return fuse_notify_poll_wakeup(fc, &outarg);
1307
1308 err:
1309 fuse_copy_finish(cs);
1310 return err;
1311 }
1312
1313 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1314 struct fuse_copy_state *cs)
1315 {
1316 struct fuse_notify_inval_inode_out outarg;
1317 int err = -EINVAL;
1318
1319 if (size != sizeof(outarg))
1320 goto err;
1321
1322 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1323 if (err)
1324 goto err;
1325 fuse_copy_finish(cs);
1326
1327 down_read(&fc->killsb);
1328 err = -ENOENT;
1329 if (fc->sb) {
1330 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1331 outarg.off, outarg.len);
1332 }
1333 up_read(&fc->killsb);
1334 return err;
1335
1336 err:
1337 fuse_copy_finish(cs);
1338 return err;
1339 }
1340
1341 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1342 struct fuse_copy_state *cs)
1343 {
1344 struct fuse_notify_inval_entry_out outarg;
1345 int err = -ENOMEM;
1346 char *buf;
1347 struct qstr name;
1348
1349 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1350 if (!buf)
1351 goto err;
1352
1353 err = -EINVAL;
1354 if (size < sizeof(outarg))
1355 goto err;
1356
1357 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1358 if (err)
1359 goto err;
1360
1361 err = -ENAMETOOLONG;
1362 if (outarg.namelen > FUSE_NAME_MAX)
1363 goto err;
1364
1365 err = -EINVAL;
1366 if (size != sizeof(outarg) + outarg.namelen + 1)
1367 goto err;
1368
1369 name.name = buf;
1370 name.len = outarg.namelen;
1371 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1372 if (err)
1373 goto err;
1374 fuse_copy_finish(cs);
1375 buf[outarg.namelen] = 0;
1376 name.hash = full_name_hash(name.name, name.len);
1377
1378 down_read(&fc->killsb);
1379 err = -ENOENT;
1380 if (fc->sb)
1381 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1382 up_read(&fc->killsb);
1383 kfree(buf);
1384 return err;
1385
1386 err:
1387 kfree(buf);
1388 fuse_copy_finish(cs);
1389 return err;
1390 }
1391
1392 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1393 struct fuse_copy_state *cs)
1394 {
1395 struct fuse_notify_delete_out outarg;
1396 int err = -ENOMEM;
1397 char *buf;
1398 struct qstr name;
1399
1400 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1401 if (!buf)
1402 goto err;
1403
1404 err = -EINVAL;
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 err = -ENAMETOOLONG;
1413 if (outarg.namelen > FUSE_NAME_MAX)
1414 goto err;
1415
1416 err = -EINVAL;
1417 if (size != sizeof(outarg) + outarg.namelen + 1)
1418 goto err;
1419
1420 name.name = buf;
1421 name.len = outarg.namelen;
1422 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1423 if (err)
1424 goto err;
1425 fuse_copy_finish(cs);
1426 buf[outarg.namelen] = 0;
1427 name.hash = full_name_hash(name.name, name.len);
1428
1429 down_read(&fc->killsb);
1430 err = -ENOENT;
1431 if (fc->sb)
1432 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1433 outarg.child, &name);
1434 up_read(&fc->killsb);
1435 kfree(buf);
1436 return err;
1437
1438 err:
1439 kfree(buf);
1440 fuse_copy_finish(cs);
1441 return err;
1442 }
1443
1444 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1445 struct fuse_copy_state *cs)
1446 {
1447 struct fuse_notify_store_out outarg;
1448 struct inode *inode;
1449 struct address_space *mapping;
1450 u64 nodeid;
1451 int err;
1452 pgoff_t index;
1453 unsigned int offset;
1454 unsigned int num;
1455 loff_t file_size;
1456 loff_t end;
1457
1458 err = -EINVAL;
1459 if (size < sizeof(outarg))
1460 goto out_finish;
1461
1462 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1463 if (err)
1464 goto out_finish;
1465
1466 err = -EINVAL;
1467 if (size - sizeof(outarg) != outarg.size)
1468 goto out_finish;
1469
1470 nodeid = outarg.nodeid;
1471
1472 down_read(&fc->killsb);
1473
1474 err = -ENOENT;
1475 if (!fc->sb)
1476 goto out_up_killsb;
1477
1478 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1479 if (!inode)
1480 goto out_up_killsb;
1481
1482 mapping = inode->i_mapping;
1483 index = outarg.offset >> PAGE_CACHE_SHIFT;
1484 offset = outarg.offset & ~PAGE_CACHE_MASK;
1485 file_size = i_size_read(inode);
1486 end = outarg.offset + outarg.size;
1487 if (end > file_size) {
1488 file_size = end;
1489 fuse_write_update_size(inode, file_size);
1490 }
1491
1492 num = outarg.size;
1493 while (num) {
1494 struct page *page;
1495 unsigned int this_num;
1496
1497 err = -ENOMEM;
1498 page = find_or_create_page(mapping, index,
1499 mapping_gfp_mask(mapping));
1500 if (!page)
1501 goto out_iput;
1502
1503 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1504 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1505 if (!err && offset == 0 && (num != 0 || file_size == end))
1506 SetPageUptodate(page);
1507 unlock_page(page);
1508 page_cache_release(page);
1509
1510 if (err)
1511 goto out_iput;
1512
1513 num -= this_num;
1514 offset = 0;
1515 index++;
1516 }
1517
1518 err = 0;
1519
1520 out_iput:
1521 iput(inode);
1522 out_up_killsb:
1523 up_read(&fc->killsb);
1524 out_finish:
1525 fuse_copy_finish(cs);
1526 return err;
1527 }
1528
1529 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1530 {
1531 release_pages(req->pages, req->num_pages, 0);
1532 }
1533
1534 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1535 struct fuse_notify_retrieve_out *outarg)
1536 {
1537 int err;
1538 struct address_space *mapping = inode->i_mapping;
1539 struct fuse_req *req;
1540 pgoff_t index;
1541 loff_t file_size;
1542 unsigned int num;
1543 unsigned int offset;
1544 size_t total_len = 0;
1545
1546 req = fuse_get_req(fc);
1547 if (IS_ERR(req))
1548 return PTR_ERR(req);
1549
1550 offset = outarg->offset & ~PAGE_CACHE_MASK;
1551
1552 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1553 req->in.h.nodeid = outarg->nodeid;
1554 req->in.numargs = 2;
1555 req->in.argpages = 1;
1556 req->page_offset = offset;
1557 req->end = fuse_retrieve_end;
1558
1559 index = outarg->offset >> PAGE_CACHE_SHIFT;
1560 file_size = i_size_read(inode);
1561 num = outarg->size;
1562 if (outarg->offset > file_size)
1563 num = 0;
1564 else if (outarg->offset + num > file_size)
1565 num = file_size - outarg->offset;
1566
1567 while (num && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
1568 struct page *page;
1569 unsigned int this_num;
1570
1571 page = find_get_page(mapping, index);
1572 if (!page)
1573 break;
1574
1575 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1576 req->pages[req->num_pages] = page;
1577 req->num_pages++;
1578
1579 num -= this_num;
1580 total_len += this_num;
1581 index++;
1582 }
1583 req->misc.retrieve_in.offset = outarg->offset;
1584 req->misc.retrieve_in.size = total_len;
1585 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1586 req->in.args[0].value = &req->misc.retrieve_in;
1587 req->in.args[1].size = total_len;
1588
1589 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1590 if (err)
1591 fuse_retrieve_end(fc, req);
1592
1593 return err;
1594 }
1595
1596 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1597 struct fuse_copy_state *cs)
1598 {
1599 struct fuse_notify_retrieve_out outarg;
1600 struct inode *inode;
1601 int err;
1602
1603 err = -EINVAL;
1604 if (size != sizeof(outarg))
1605 goto copy_finish;
1606
1607 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1608 if (err)
1609 goto copy_finish;
1610
1611 fuse_copy_finish(cs);
1612
1613 down_read(&fc->killsb);
1614 err = -ENOENT;
1615 if (fc->sb) {
1616 u64 nodeid = outarg.nodeid;
1617
1618 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1619 if (inode) {
1620 err = fuse_retrieve(fc, inode, &outarg);
1621 iput(inode);
1622 }
1623 }
1624 up_read(&fc->killsb);
1625
1626 return err;
1627
1628 copy_finish:
1629 fuse_copy_finish(cs);
1630 return err;
1631 }
1632
1633 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1634 unsigned int size, struct fuse_copy_state *cs)
1635 {
1636 switch (code) {
1637 case FUSE_NOTIFY_POLL:
1638 return fuse_notify_poll(fc, size, cs);
1639
1640 case FUSE_NOTIFY_INVAL_INODE:
1641 return fuse_notify_inval_inode(fc, size, cs);
1642
1643 case FUSE_NOTIFY_INVAL_ENTRY:
1644 return fuse_notify_inval_entry(fc, size, cs);
1645
1646 case FUSE_NOTIFY_STORE:
1647 return fuse_notify_store(fc, size, cs);
1648
1649 case FUSE_NOTIFY_RETRIEVE:
1650 return fuse_notify_retrieve(fc, size, cs);
1651
1652 case FUSE_NOTIFY_DELETE:
1653 return fuse_notify_delete(fc, size, cs);
1654
1655 default:
1656 fuse_copy_finish(cs);
1657 return -EINVAL;
1658 }
1659 }
1660
1661 /* Look up request on processing list by unique ID */
1662 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1663 {
1664 struct list_head *entry;
1665
1666 list_for_each(entry, &fc->processing) {
1667 struct fuse_req *req;
1668 req = list_entry(entry, struct fuse_req, list);
1669 if (req->in.h.unique == unique || req->intr_unique == unique)
1670 return req;
1671 }
1672 return NULL;
1673 }
1674
1675 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1676 unsigned nbytes)
1677 {
1678 unsigned reqsize = sizeof(struct fuse_out_header);
1679
1680 if (out->h.error)
1681 return nbytes != reqsize ? -EINVAL : 0;
1682
1683 reqsize += len_args(out->numargs, out->args);
1684
1685 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1686 return -EINVAL;
1687 else if (reqsize > nbytes) {
1688 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1689 unsigned diffsize = reqsize - nbytes;
1690 if (diffsize > lastarg->size)
1691 return -EINVAL;
1692 lastarg->size -= diffsize;
1693 }
1694 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1695 out->page_zeroing);
1696 }
1697
1698 /*
1699 * Write a single reply to a request. First the header is copied from
1700 * the write buffer. The request is then searched on the processing
1701 * list by the unique ID found in the header. If found, then remove
1702 * it from the list and copy the rest of the buffer to the request.
1703 * The request is finished by calling request_end()
1704 */
1705 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1706 struct fuse_copy_state *cs, size_t nbytes)
1707 {
1708 int err;
1709 struct fuse_req *req;
1710 struct fuse_out_header oh;
1711
1712 if (nbytes < sizeof(struct fuse_out_header))
1713 return -EINVAL;
1714
1715 err = fuse_copy_one(cs, &oh, sizeof(oh));
1716 if (err)
1717 goto err_finish;
1718
1719 err = -EINVAL;
1720 if (oh.len != nbytes)
1721 goto err_finish;
1722
1723 /*
1724 * Zero oh.unique indicates unsolicited notification message
1725 * and error contains notification code.
1726 */
1727 if (!oh.unique) {
1728 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1729 return err ? err : nbytes;
1730 }
1731
1732 err = -EINVAL;
1733 if (oh.error <= -1000 || oh.error > 0)
1734 goto err_finish;
1735
1736 spin_lock(&fc->lock);
1737 err = -ENOENT;
1738 if (!fc->connected)
1739 goto err_unlock;
1740
1741 req = request_find(fc, oh.unique);
1742 if (!req)
1743 goto err_unlock;
1744
1745 if (req->aborted) {
1746 spin_unlock(&fc->lock);
1747 fuse_copy_finish(cs);
1748 spin_lock(&fc->lock);
1749 request_end(fc, req);
1750 return -ENOENT;
1751 }
1752 /* Is it an interrupt reply? */
1753 if (req->intr_unique == oh.unique) {
1754 err = -EINVAL;
1755 if (nbytes != sizeof(struct fuse_out_header))
1756 goto err_unlock;
1757
1758 if (oh.error == -ENOSYS)
1759 fc->no_interrupt = 1;
1760 else if (oh.error == -EAGAIN)
1761 queue_interrupt(fc, req);
1762
1763 spin_unlock(&fc->lock);
1764 fuse_copy_finish(cs);
1765 return nbytes;
1766 }
1767
1768 req->state = FUSE_REQ_WRITING;
1769 list_move(&req->list, &fc->io);
1770 req->out.h = oh;
1771 req->locked = 1;
1772 cs->req = req;
1773 if (!req->out.page_replace)
1774 cs->move_pages = 0;
1775 spin_unlock(&fc->lock);
1776
1777 err = copy_out_args(cs, &req->out, nbytes);
1778 fuse_copy_finish(cs);
1779
1780 spin_lock(&fc->lock);
1781 req->locked = 0;
1782 if (!err) {
1783 if (req->aborted)
1784 err = -ENOENT;
1785 } else if (!req->aborted)
1786 req->out.h.error = -EIO;
1787 request_end(fc, req);
1788
1789 return err ? err : nbytes;
1790
1791 err_unlock:
1792 spin_unlock(&fc->lock);
1793 err_finish:
1794 fuse_copy_finish(cs);
1795 return err;
1796 }
1797
1798 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1799 unsigned long nr_segs, loff_t pos)
1800 {
1801 struct fuse_copy_state cs;
1802 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1803 if (!fc)
1804 return -EPERM;
1805
1806 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1807
1808 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1809 }
1810
1811 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1812 struct file *out, loff_t *ppos,
1813 size_t len, unsigned int flags)
1814 {
1815 unsigned nbuf;
1816 unsigned idx;
1817 struct pipe_buffer *bufs;
1818 struct fuse_copy_state cs;
1819 struct fuse_conn *fc;
1820 size_t rem;
1821 ssize_t ret;
1822
1823 fc = fuse_get_conn(out);
1824 if (!fc)
1825 return -EPERM;
1826
1827 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1828 if (!bufs)
1829 return -ENOMEM;
1830
1831 pipe_lock(pipe);
1832 nbuf = 0;
1833 rem = 0;
1834 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1835 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1836
1837 ret = -EINVAL;
1838 if (rem < len) {
1839 pipe_unlock(pipe);
1840 goto out;
1841 }
1842
1843 rem = len;
1844 while (rem) {
1845 struct pipe_buffer *ibuf;
1846 struct pipe_buffer *obuf;
1847
1848 BUG_ON(nbuf >= pipe->buffers);
1849 BUG_ON(!pipe->nrbufs);
1850 ibuf = &pipe->bufs[pipe->curbuf];
1851 obuf = &bufs[nbuf];
1852
1853 if (rem >= ibuf->len) {
1854 *obuf = *ibuf;
1855 ibuf->ops = NULL;
1856 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1857 pipe->nrbufs--;
1858 } else {
1859 ibuf->ops->get(pipe, ibuf);
1860 *obuf = *ibuf;
1861 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1862 obuf->len = rem;
1863 ibuf->offset += obuf->len;
1864 ibuf->len -= obuf->len;
1865 }
1866 nbuf++;
1867 rem -= obuf->len;
1868 }
1869 pipe_unlock(pipe);
1870
1871 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1872 cs.pipebufs = bufs;
1873 cs.pipe = pipe;
1874
1875 if (flags & SPLICE_F_MOVE)
1876 cs.move_pages = 1;
1877
1878 ret = fuse_dev_do_write(fc, &cs, len);
1879
1880 for (idx = 0; idx < nbuf; idx++) {
1881 struct pipe_buffer *buf = &bufs[idx];
1882 buf->ops->release(pipe, buf);
1883 }
1884 out:
1885 kfree(bufs);
1886 return ret;
1887 }
1888
1889 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1890 {
1891 unsigned mask = POLLOUT | POLLWRNORM;
1892 struct fuse_conn *fc = fuse_get_conn(file);
1893 if (!fc)
1894 return POLLERR;
1895
1896 poll_wait(file, &fc->waitq, wait);
1897
1898 spin_lock(&fc->lock);
1899 if (!fc->connected)
1900 mask = POLLERR;
1901 else if (request_pending(fc))
1902 mask |= POLLIN | POLLRDNORM;
1903 spin_unlock(&fc->lock);
1904
1905 return mask;
1906 }
1907
1908 /*
1909 * Abort all requests on the given list (pending or processing)
1910 *
1911 * This function releases and reacquires fc->lock
1912 */
1913 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1914 __releases(fc->lock)
1915 __acquires(fc->lock)
1916 {
1917 while (!list_empty(head)) {
1918 struct fuse_req *req;
1919 req = list_entry(head->next, struct fuse_req, list);
1920 req->out.h.error = -ECONNABORTED;
1921 request_end(fc, req);
1922 spin_lock(&fc->lock);
1923 }
1924 }
1925
1926 /*
1927 * Abort requests under I/O
1928 *
1929 * The requests are set to aborted and finished, and the request
1930 * waiter is woken up. This will make request_wait_answer() wait
1931 * until the request is unlocked and then return.
1932 *
1933 * If the request is asynchronous, then the end function needs to be
1934 * called after waiting for the request to be unlocked (if it was
1935 * locked).
1936 */
1937 static void end_io_requests(struct fuse_conn *fc)
1938 __releases(fc->lock)
1939 __acquires(fc->lock)
1940 {
1941 while (!list_empty(&fc->io)) {
1942 struct fuse_req *req =
1943 list_entry(fc->io.next, struct fuse_req, list);
1944 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1945
1946 req->aborted = 1;
1947 req->out.h.error = -ECONNABORTED;
1948 req->state = FUSE_REQ_FINISHED;
1949 list_del_init(&req->list);
1950 wake_up(&req->waitq);
1951 if (end) {
1952 req->end = NULL;
1953 __fuse_get_request(req);
1954 spin_unlock(&fc->lock);
1955 wait_event(req->waitq, !req->locked);
1956 end(fc, req);
1957 fuse_put_request(fc, req);
1958 spin_lock(&fc->lock);
1959 }
1960 }
1961 }
1962
1963 static void end_queued_requests(struct fuse_conn *fc)
1964 __releases(fc->lock)
1965 __acquires(fc->lock)
1966 {
1967 fc->max_background = UINT_MAX;
1968 flush_bg_queue(fc);
1969 end_requests(fc, &fc->pending);
1970 end_requests(fc, &fc->processing);
1971 while (forget_pending(fc))
1972 kfree(dequeue_forget(fc, 1, NULL));
1973 }
1974
1975 static void end_polls(struct fuse_conn *fc)
1976 {
1977 struct rb_node *p;
1978
1979 p = rb_first(&fc->polled_files);
1980
1981 while (p) {
1982 struct fuse_file *ff;
1983 ff = rb_entry(p, struct fuse_file, polled_node);
1984 wake_up_interruptible_all(&ff->poll_wait);
1985
1986 p = rb_next(p);
1987 }
1988 }
1989
1990 /*
1991 * Abort all requests.
1992 *
1993 * Emergency exit in case of a malicious or accidental deadlock, or
1994 * just a hung filesystem.
1995 *
1996 * The same effect is usually achievable through killing the
1997 * filesystem daemon and all users of the filesystem. The exception
1998 * is the combination of an asynchronous request and the tricky
1999 * deadlock (see Documentation/filesystems/fuse.txt).
2000 *
2001 * During the aborting, progression of requests from the pending and
2002 * processing lists onto the io list, and progression of new requests
2003 * onto the pending list is prevented by req->connected being false.
2004 *
2005 * Progression of requests under I/O to the processing list is
2006 * prevented by the req->aborted flag being true for these requests.
2007 * For this reason requests on the io list must be aborted first.
2008 */
2009 void fuse_abort_conn(struct fuse_conn *fc)
2010 {
2011 spin_lock(&fc->lock);
2012 if (fc->connected) {
2013 fc->connected = 0;
2014 fc->blocked = 0;
2015 end_io_requests(fc);
2016 end_queued_requests(fc);
2017 end_polls(fc);
2018 wake_up_all(&fc->waitq);
2019 wake_up_all(&fc->blocked_waitq);
2020 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
2021 }
2022 spin_unlock(&fc->lock);
2023 }
2024 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2025
2026 int fuse_dev_release(struct inode *inode, struct file *file)
2027 {
2028 struct fuse_conn *fc = fuse_get_conn(file);
2029 if (fc) {
2030 spin_lock(&fc->lock);
2031 fc->connected = 0;
2032 fc->blocked = 0;
2033 end_queued_requests(fc);
2034 end_polls(fc);
2035 wake_up_all(&fc->blocked_waitq);
2036 spin_unlock(&fc->lock);
2037 fuse_conn_put(fc);
2038 }
2039
2040 return 0;
2041 }
2042 EXPORT_SYMBOL_GPL(fuse_dev_release);
2043
2044 static int fuse_dev_fasync(int fd, struct file *file, int on)
2045 {
2046 struct fuse_conn *fc = fuse_get_conn(file);
2047 if (!fc)
2048 return -EPERM;
2049
2050 /* No locking - fasync_helper does its own locking */
2051 return fasync_helper(fd, file, on, &fc->fasync);
2052 }
2053
2054 const struct file_operations fuse_dev_operations = {
2055 .owner = THIS_MODULE,
2056 .llseek = no_llseek,
2057 .read = do_sync_read,
2058 .aio_read = fuse_dev_read,
2059 .splice_read = fuse_dev_splice_read,
2060 .write = do_sync_write,
2061 .aio_write = fuse_dev_write,
2062 .splice_write = fuse_dev_splice_write,
2063 .poll = fuse_dev_poll,
2064 .release = fuse_dev_release,
2065 .fasync = fuse_dev_fasync,
2066 };
2067 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2068
2069 static struct miscdevice fuse_miscdevice = {
2070 .minor = FUSE_MINOR,
2071 .name = "fuse",
2072 .fops = &fuse_dev_operations,
2073 };
2074
2075 int __init fuse_dev_init(void)
2076 {
2077 int err = -ENOMEM;
2078 fuse_req_cachep = kmem_cache_create("fuse_request",
2079 sizeof(struct fuse_req),
2080 0, 0, NULL);
2081 if (!fuse_req_cachep)
2082 goto out;
2083
2084 err = misc_register(&fuse_miscdevice);
2085 if (err)
2086 goto out_cache_clean;
2087
2088 return 0;
2089
2090 out_cache_clean:
2091 kmem_cache_destroy(fuse_req_cachep);
2092 out:
2093 return err;
2094 }
2095
2096 void fuse_dev_cleanup(void)
2097 {
2098 misc_deregister(&fuse_miscdevice);
2099 kmem_cache_destroy(fuse_req_cachep);
2100 }