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