projects/linux·blob v3.2 · refs

2045 lines · 45.2 KiB

1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <[email protected]>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7*/
8
9#include "fuse_i.h"
10
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/poll.h>
14#include <linux/uio.h>
15#include <linux/miscdevice.h>
16#include <linux/pagemap.h>
17#include <linux/file.h>
18#include <linux/slab.h>
19#include <linux/pipe_fs_i.h>
20#include <linux/swap.h>
21#include <linux/splice.h>
22
23MODULE_ALIAS_MISCDEV(FUSE_MINOR);
24MODULE_ALIAS("devname:fuse");
25
26static struct kmem_cache *fuse_req_cachep;
27
28static struct fuse_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
37static 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
46struct 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}
53EXPORT_SYMBOL_GPL(fuse_request_alloc);
54
55struct 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
63void fuse_request_free(struct fuse_req *req)
64{
65 kmem_cache_free(fuse_req_cachep, req);
66}
67
68static 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
76static void restore_sigs(sigset_t *oldset)
77{
78 sigprocmask(SIG_SETMASK, oldset, NULL);
79}
80
81static void __fuse_get_request(struct fuse_req *req)
82{
83 atomic_inc(&req->count);
84}
85
86/* Must be called with > 1 refcount */
87static void __fuse_put_request(struct fuse_req *req)
88{
89 BUG_ON(atomic_read(&req->count) < 2);
90 atomic_dec(&req->count);
91}
92
93static 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
100struct 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}
132EXPORT_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 */
139static 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 */
163static 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 */
190struct 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
205void 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}
217EXPORT_SYMBOL_GPL(fuse_put_request);
218
219static 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
230static 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
240static 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
254void 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
272static 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 */
296static 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
325static 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
338static 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
345static 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
410void 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}
429EXPORT_SYMBOL_GPL(fuse_request_send);
430
431static 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
447static 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
459void 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}
464EXPORT_SYMBOL_GPL(fuse_request_send_background);
465
466static 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 */
488void 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 */
500static 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 */
519static 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
530struct 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
548static 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 */
560static 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 */
588static 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 */
655static 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
671static 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
690static 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
775out_fallback_unlock:
776 unlock_page(newpage);
777out_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
788static 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 */
816static 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 */
854static 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 */
878static 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 */
892static 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
909static int forget_pending(struct fuse_conn *fc)
910{
911 return fc->forget_list_head.next != NULL;
912}
913
914static 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 */
921static 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 */
949static 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
979static 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
1001static 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
1034static 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
1083static 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 */
1102static 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
1188static 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
1202static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1203 struct pipe_buffer *buf)
1204{
1205 return 1;
1206}
1207
1208static 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
1218static 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
1274out_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
1284out:
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
1292static 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
1308err:
1309 fuse_copy_finish(cs);
1310 return err;
1311}
1312
1313static 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
1336err:
1337 fuse_copy_finish(cs);
1338 return err;
1339}
1340
1341static 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, &name);
1382 up_read(&fc->killsb);
1383 kfree(buf);
1384 return err;
1385
1386err:
1387 kfree(buf);
1388 fuse_copy_finish(cs);
1389 return err;
1390}
1391
1392static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1393 struct fuse_copy_state *cs)
1394{
1395 struct fuse_notify_store_out outarg;
1396 struct inode *inode;
1397 struct address_space *mapping;
1398 u64 nodeid;
1399 int err;
1400 pgoff_t index;
1401 unsigned int offset;
1402 unsigned int num;
1403 loff_t file_size;
1404 loff_t end;
1405
1406 err = -EINVAL;
1407 if (size < sizeof(outarg))
1408 goto out_finish;
1409
1410 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1411 if (err)
1412 goto out_finish;
1413
1414 err = -EINVAL;
1415 if (size - sizeof(outarg) != outarg.size)
1416 goto out_finish;
1417
1418 nodeid = outarg.nodeid;
1419
1420 down_read(&fc->killsb);
1421
1422 err = -ENOENT;
1423 if (!fc->sb)
1424 goto out_up_killsb;
1425
1426 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1427 if (!inode)
1428 goto out_up_killsb;
1429
1430 mapping = inode->i_mapping;
1431 index = outarg.offset >> PAGE_CACHE_SHIFT;
1432 offset = outarg.offset & ~PAGE_CACHE_MASK;
1433 file_size = i_size_read(inode);
1434 end = outarg.offset + outarg.size;
1435 if (end > file_size) {
1436 file_size = end;
1437 fuse_write_update_size(inode, file_size);
1438 }
1439
1440 num = outarg.size;
1441 while (num) {
1442 struct page *page;
1443 unsigned int this_num;
1444
1445 err = -ENOMEM;
1446 page = find_or_create_page(mapping, index,
1447 mapping_gfp_mask(mapping));
1448 if (!page)
1449 goto out_iput;
1450
1451 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1452 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1453 if (!err && offset == 0 && (num != 0 || file_size == end))
1454 SetPageUptodate(page);
1455 unlock_page(page);
1456 page_cache_release(page);
1457
1458 if (err)
1459 goto out_iput;
1460
1461 num -= this_num;
1462 offset = 0;
1463 index++;
1464 }
1465
1466 err = 0;
1467
1468out_iput:
1469 iput(inode);
1470out_up_killsb:
1471 up_read(&fc->killsb);
1472out_finish:
1473 fuse_copy_finish(cs);
1474 return err;
1475}
1476
1477static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1478{
1479 release_pages(req->pages, req->num_pages, 0);
1480}
1481
1482static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1483 struct fuse_notify_retrieve_out *outarg)
1484{
1485 int err;
1486 struct address_space *mapping = inode->i_mapping;
1487 struct fuse_req *req;
1488 pgoff_t index;
1489 loff_t file_size;
1490 unsigned int num;
1491 unsigned int offset;
1492 size_t total_len = 0;
1493
1494 req = fuse_get_req(fc);
1495 if (IS_ERR(req))
1496 return PTR_ERR(req);
1497
1498 offset = outarg->offset & ~PAGE_CACHE_MASK;
1499
1500 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1501 req->in.h.nodeid = outarg->nodeid;
1502 req->in.numargs = 2;
1503 req->in.argpages = 1;
1504 req->page_offset = offset;
1505 req->end = fuse_retrieve_end;
1506
1507 index = outarg->offset >> PAGE_CACHE_SHIFT;
1508 file_size = i_size_read(inode);
1509 num = outarg->size;
1510 if (outarg->offset > file_size)
1511 num = 0;
1512 else if (outarg->offset + num > file_size)
1513 num = file_size - outarg->offset;
1514
1515 while (num && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
1516 struct page *page;
1517 unsigned int this_num;
1518
1519 page = find_get_page(mapping, index);
1520 if (!page)
1521 break;
1522
1523 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1524 req->pages[req->num_pages] = page;
1525 req->num_pages++;
1526
1527 num -= this_num;
1528 total_len += this_num;
1529 index++;
1530 }
1531 req->misc.retrieve_in.offset = outarg->offset;
1532 req->misc.retrieve_in.size = total_len;
1533 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1534 req->in.args[0].value = &req->misc.retrieve_in;
1535 req->in.args[1].size = total_len;
1536
1537 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1538 if (err)
1539 fuse_retrieve_end(fc, req);
1540
1541 return err;
1542}
1543
1544static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1545 struct fuse_copy_state *cs)
1546{
1547 struct fuse_notify_retrieve_out outarg;
1548 struct inode *inode;
1549 int err;
1550
1551 err = -EINVAL;
1552 if (size != sizeof(outarg))
1553 goto copy_finish;
1554
1555 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1556 if (err)
1557 goto copy_finish;
1558
1559 fuse_copy_finish(cs);
1560
1561 down_read(&fc->killsb);
1562 err = -ENOENT;
1563 if (fc->sb) {
1564 u64 nodeid = outarg.nodeid;
1565
1566 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1567 if (inode) {
1568 err = fuse_retrieve(fc, inode, &outarg);
1569 iput(inode);
1570 }
1571 }
1572 up_read(&fc->killsb);
1573
1574 return err;
1575
1576copy_finish:
1577 fuse_copy_finish(cs);
1578 return err;
1579}
1580
1581static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1582 unsigned int size, struct fuse_copy_state *cs)
1583{
1584 switch (code) {
1585 case FUSE_NOTIFY_POLL:
1586 return fuse_notify_poll(fc, size, cs);
1587
1588 case FUSE_NOTIFY_INVAL_INODE:
1589 return fuse_notify_inval_inode(fc, size, cs);
1590
1591 case FUSE_NOTIFY_INVAL_ENTRY:
1592 return fuse_notify_inval_entry(fc, size, cs);
1593
1594 case FUSE_NOTIFY_STORE:
1595 return fuse_notify_store(fc, size, cs);
1596
1597 case FUSE_NOTIFY_RETRIEVE:
1598 return fuse_notify_retrieve(fc, size, cs);
1599
1600 default:
1601 fuse_copy_finish(cs);
1602 return -EINVAL;
1603 }
1604}
1605
1606/* Look up request on processing list by unique ID */
1607static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1608{
1609 struct list_head *entry;
1610
1611 list_for_each(entry, &fc->processing) {
1612 struct fuse_req *req;
1613 req = list_entry(entry, struct fuse_req, list);
1614 if (req->in.h.unique == unique || req->intr_unique == unique)
1615 return req;
1616 }
1617 return NULL;
1618}
1619
1620static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1621 unsigned nbytes)
1622{
1623 unsigned reqsize = sizeof(struct fuse_out_header);
1624
1625 if (out->h.error)
1626 return nbytes != reqsize ? -EINVAL : 0;
1627
1628 reqsize += len_args(out->numargs, out->args);
1629
1630 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1631 return -EINVAL;
1632 else if (reqsize > nbytes) {
1633 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1634 unsigned diffsize = reqsize - nbytes;
1635 if (diffsize > lastarg->size)
1636 return -EINVAL;
1637 lastarg->size -= diffsize;
1638 }
1639 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1640 out->page_zeroing);
1641}
1642
1643/*
1644 * Write a single reply to a request. First the header is copied from
1645 * the write buffer. The request is then searched on the processing
1646 * list by the unique ID found in the header. If found, then remove
1647 * it from the list and copy the rest of the buffer to the request.
1648 * The request is finished by calling request_end()
1649 */
1650static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1651 struct fuse_copy_state *cs, size_t nbytes)
1652{
1653 int err;
1654 struct fuse_req *req;
1655 struct fuse_out_header oh;
1656
1657 if (nbytes < sizeof(struct fuse_out_header))
1658 return -EINVAL;
1659
1660 err = fuse_copy_one(cs, &oh, sizeof(oh));
1661 if (err)
1662 goto err_finish;
1663
1664 err = -EINVAL;
1665 if (oh.len != nbytes)
1666 goto err_finish;
1667
1668 /*
1669 * Zero oh.unique indicates unsolicited notification message
1670 * and error contains notification code.
1671 */
1672 if (!oh.unique) {
1673 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1674 return err ? err : nbytes;
1675 }
1676
1677 err = -EINVAL;
1678 if (oh.error <= -1000 || oh.error > 0)
1679 goto err_finish;
1680
1681 spin_lock(&fc->lock);
1682 err = -ENOENT;
1683 if (!fc->connected)
1684 goto err_unlock;
1685
1686 req = request_find(fc, oh.unique);
1687 if (!req)
1688 goto err_unlock;
1689
1690 if (req->aborted) {
1691 spin_unlock(&fc->lock);
1692 fuse_copy_finish(cs);
1693 spin_lock(&fc->lock);
1694 request_end(fc, req);
1695 return -ENOENT;
1696 }
1697 /* Is it an interrupt reply? */
1698 if (req->intr_unique == oh.unique) {
1699 err = -EINVAL;
1700 if (nbytes != sizeof(struct fuse_out_header))
1701 goto err_unlock;
1702
1703 if (oh.error == -ENOSYS)
1704 fc->no_interrupt = 1;
1705 else if (oh.error == -EAGAIN)
1706 queue_interrupt(fc, req);
1707
1708 spin_unlock(&fc->lock);
1709 fuse_copy_finish(cs);
1710 return nbytes;
1711 }
1712
1713 req->state = FUSE_REQ_WRITING;
1714 list_move(&req->list, &fc->io);
1715 req->out.h = oh;
1716 req->locked = 1;
1717 cs->req = req;
1718 if (!req->out.page_replace)
1719 cs->move_pages = 0;
1720 spin_unlock(&fc->lock);
1721
1722 err = copy_out_args(cs, &req->out, nbytes);
1723 fuse_copy_finish(cs);
1724
1725 spin_lock(&fc->lock);
1726 req->locked = 0;
1727 if (!err) {
1728 if (req->aborted)
1729 err = -ENOENT;
1730 } else if (!req->aborted)
1731 req->out.h.error = -EIO;
1732 request_end(fc, req);
1733
1734 return err ? err : nbytes;
1735
1736 err_unlock:
1737 spin_unlock(&fc->lock);
1738 err_finish:
1739 fuse_copy_finish(cs);
1740 return err;
1741}
1742
1743static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1744 unsigned long nr_segs, loff_t pos)
1745{
1746 struct fuse_copy_state cs;
1747 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1748 if (!fc)
1749 return -EPERM;
1750
1751 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1752
1753 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1754}
1755
1756static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1757 struct file *out, loff_t *ppos,
1758 size_t len, unsigned int flags)
1759{
1760 unsigned nbuf;
1761 unsigned idx;
1762 struct pipe_buffer *bufs;
1763 struct fuse_copy_state cs;
1764 struct fuse_conn *fc;
1765 size_t rem;
1766 ssize_t ret;
1767
1768 fc = fuse_get_conn(out);
1769 if (!fc)
1770 return -EPERM;
1771
1772 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1773 if (!bufs)
1774 return -ENOMEM;
1775
1776 pipe_lock(pipe);
1777 nbuf = 0;
1778 rem = 0;
1779 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1780 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1781
1782 ret = -EINVAL;
1783 if (rem < len) {
1784 pipe_unlock(pipe);
1785 goto out;
1786 }
1787
1788 rem = len;
1789 while (rem) {
1790 struct pipe_buffer *ibuf;
1791 struct pipe_buffer *obuf;
1792
1793 BUG_ON(nbuf >= pipe->buffers);
1794 BUG_ON(!pipe->nrbufs);
1795 ibuf = &pipe->bufs[pipe->curbuf];
1796 obuf = &bufs[nbuf];
1797
1798 if (rem >= ibuf->len) {
1799 *obuf = *ibuf;
1800 ibuf->ops = NULL;
1801 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1802 pipe->nrbufs--;
1803 } else {
1804 ibuf->ops->get(pipe, ibuf);
1805 *obuf = *ibuf;
1806 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1807 obuf->len = rem;
1808 ibuf->offset += obuf->len;
1809 ibuf->len -= obuf->len;
1810 }
1811 nbuf++;
1812 rem -= obuf->len;
1813 }
1814 pipe_unlock(pipe);
1815
1816 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1817 cs.pipebufs = bufs;
1818 cs.pipe = pipe;
1819
1820 if (flags & SPLICE_F_MOVE)
1821 cs.move_pages = 1;
1822
1823 ret = fuse_dev_do_write(fc, &cs, len);
1824
1825 for (idx = 0; idx < nbuf; idx++) {
1826 struct pipe_buffer *buf = &bufs[idx];
1827 buf->ops->release(pipe, buf);
1828 }
1829out:
1830 kfree(bufs);
1831 return ret;
1832}
1833
1834static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1835{
1836 unsigned mask = POLLOUT | POLLWRNORM;
1837 struct fuse_conn *fc = fuse_get_conn(file);
1838 if (!fc)
1839 return POLLERR;
1840
1841 poll_wait(file, &fc->waitq, wait);
1842
1843 spin_lock(&fc->lock);
1844 if (!fc->connected)
1845 mask = POLLERR;
1846 else if (request_pending(fc))
1847 mask |= POLLIN | POLLRDNORM;
1848 spin_unlock(&fc->lock);
1849
1850 return mask;
1851}
1852
1853/*
1854 * Abort all requests on the given list (pending or processing)
1855 *
1856 * This function releases and reacquires fc->lock
1857 */
1858static void end_requests(struct fuse_conn *fc, struct list_head *head)
1859__releases(fc->lock)
1860__acquires(fc->lock)
1861{
1862 while (!list_empty(head)) {
1863 struct fuse_req *req;
1864 req = list_entry(head->next, struct fuse_req, list);
1865 req->out.h.error = -ECONNABORTED;
1866 request_end(fc, req);
1867 spin_lock(&fc->lock);
1868 }
1869}
1870
1871/*
1872 * Abort requests under I/O
1873 *
1874 * The requests are set to aborted and finished, and the request
1875 * waiter is woken up. This will make request_wait_answer() wait
1876 * until the request is unlocked and then return.
1877 *
1878 * If the request is asynchronous, then the end function needs to be
1879 * called after waiting for the request to be unlocked (if it was
1880 * locked).
1881 */
1882static void end_io_requests(struct fuse_conn *fc)
1883__releases(fc->lock)
1884__acquires(fc->lock)
1885{
1886 while (!list_empty(&fc->io)) {
1887 struct fuse_req *req =
1888 list_entry(fc->io.next, struct fuse_req, list);
1889 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1890
1891 req->aborted = 1;
1892 req->out.h.error = -ECONNABORTED;
1893 req->state = FUSE_REQ_FINISHED;
1894 list_del_init(&req->list);
1895 wake_up(&req->waitq);
1896 if (end) {
1897 req->end = NULL;
1898 __fuse_get_request(req);
1899 spin_unlock(&fc->lock);
1900 wait_event(req->waitq, !req->locked);
1901 end(fc, req);
1902 fuse_put_request(fc, req);
1903 spin_lock(&fc->lock);
1904 }
1905 }
1906}
1907
1908static void end_queued_requests(struct fuse_conn *fc)
1909__releases(fc->lock)
1910__acquires(fc->lock)
1911{
1912 fc->max_background = UINT_MAX;
1913 flush_bg_queue(fc);
1914 end_requests(fc, &fc->pending);
1915 end_requests(fc, &fc->processing);
1916 while (forget_pending(fc))
1917 kfree(dequeue_forget(fc, 1, NULL));
1918}
1919
1920static void end_polls(struct fuse_conn *fc)
1921{
1922 struct rb_node *p;
1923
1924 p = rb_first(&fc->polled_files);
1925
1926 while (p) {
1927 struct fuse_file *ff;
1928 ff = rb_entry(p, struct fuse_file, polled_node);
1929 wake_up_interruptible_all(&ff->poll_wait);
1930
1931 p = rb_next(p);
1932 }
1933}
1934
1935/*
1936 * Abort all requests.
1937 *
1938 * Emergency exit in case of a malicious or accidental deadlock, or
1939 * just a hung filesystem.
1940 *
1941 * The same effect is usually achievable through killing the
1942 * filesystem daemon and all users of the filesystem. The exception
1943 * is the combination of an asynchronous request and the tricky
1944 * deadlock (see Documentation/filesystems/fuse.txt).
1945 *
1946 * During the aborting, progression of requests from the pending and
1947 * processing lists onto the io list, and progression of new requests
1948 * onto the pending list is prevented by req->connected being false.
1949 *
1950 * Progression of requests under I/O to the processing list is
1951 * prevented by the req->aborted flag being true for these requests.
1952 * For this reason requests on the io list must be aborted first.
1953 */
1954void fuse_abort_conn(struct fuse_conn *fc)
1955{
1956 spin_lock(&fc->lock);
1957 if (fc->connected) {
1958 fc->connected = 0;
1959 fc->blocked = 0;
1960 end_io_requests(fc);
1961 end_queued_requests(fc);
1962 end_polls(fc);
1963 wake_up_all(&fc->waitq);
1964 wake_up_all(&fc->blocked_waitq);
1965 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1966 }
1967 spin_unlock(&fc->lock);
1968}
1969EXPORT_SYMBOL_GPL(fuse_abort_conn);
1970
1971int fuse_dev_release(struct inode *inode, struct file *file)
1972{
1973 struct fuse_conn *fc = fuse_get_conn(file);
1974 if (fc) {
1975 spin_lock(&fc->lock);
1976 fc->connected = 0;
1977 fc->blocked = 0;
1978 end_queued_requests(fc);
1979 end_polls(fc);
1980 wake_up_all(&fc->blocked_waitq);
1981 spin_unlock(&fc->lock);
1982 fuse_conn_put(fc);
1983 }
1984
1985 return 0;
1986}
1987EXPORT_SYMBOL_GPL(fuse_dev_release);
1988
1989static int fuse_dev_fasync(int fd, struct file *file, int on)
1990{
1991 struct fuse_conn *fc = fuse_get_conn(file);
1992 if (!fc)
1993 return -EPERM;
1994
1995 /* No locking - fasync_helper does its own locking */
1996 return fasync_helper(fd, file, on, &fc->fasync);
1997}
1998
1999const struct file_operations fuse_dev_operations = {
2000 .owner = THIS_MODULE,
2001 .llseek = no_llseek,
2002 .read = do_sync_read,
2003 .aio_read = fuse_dev_read,
2004 .splice_read = fuse_dev_splice_read,
2005 .write = do_sync_write,
2006 .aio_write = fuse_dev_write,
2007 .splice_write = fuse_dev_splice_write,
2008 .poll = fuse_dev_poll,
2009 .release = fuse_dev_release,
2010 .fasync = fuse_dev_fasync,
2011};
2012EXPORT_SYMBOL_GPL(fuse_dev_operations);
2013
2014static struct miscdevice fuse_miscdevice = {
2015 .minor = FUSE_MINOR,
2016 .name = "fuse",
2017 .fops = &fuse_dev_operations,
2018};
2019
2020int __init fuse_dev_init(void)
2021{
2022 int err = -ENOMEM;
2023 fuse_req_cachep = kmem_cache_create("fuse_request",
2024 sizeof(struct fuse_req),
2025 0, 0, NULL);
2026 if (!fuse_req_cachep)
2027 goto out;
2028
2029 err = misc_register(&fuse_miscdevice);
2030 if (err)
2031 goto out_cache_clean;
2032
2033 return 0;
2034
2035 out_cache_clean:
2036 kmem_cache_destroy(fuse_req_cachep);
2037 out:
2038 return err;
2039}
2040
2041void fuse_dev_cleanup(void)
2042{
2043 misc_deregister(&fuse_miscdevice);
2044 kmem_cache_destroy(fuse_req_cachep);
2045}