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The discovered bit in PGCCSR register indicates if the device has been
[linux-2.6/next.git] / fs / fuse / dev.c
blob168a80f7f12b856e795eb916bf79f5e2348e06f6
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/uio.h>
15 #include <linux/miscdevice.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/slab.h>
19 #include <linux/pipe_fs_i.h>
20 #include <linux/swap.h>
21 #include <linux/splice.h>
22
23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
24 MODULE_ALIAS("devname:fuse");
25
26 static struct kmem_cache *fuse_req_cachep;
27
28 static struct fuse_conn *fuse_get_conn(struct file *file)
29 {
30 /*
31 * Lockless access is OK, because file->private data is set
32 * once during mount and is valid until the file is released.
33 */
34 return file->private_data;
35 }
36
37 static void fuse_request_init(struct fuse_req *req)
38 {
39 memset(req, 0, sizeof(*req));
40 INIT_LIST_HEAD(&req->list);
41 INIT_LIST_HEAD(&req->intr_entry);
42 init_waitqueue_head(&req->waitq);
43 atomic_set(&req->count, 1);
44 }
45
46 struct fuse_req *fuse_request_alloc(void)
47 {
48 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
49 if (req)
50 fuse_request_init(req);
51 return req;
52 }
53 EXPORT_SYMBOL_GPL(fuse_request_alloc);
54
55 struct fuse_req *fuse_request_alloc_nofs(void)
56 {
57 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
58 if (req)
59 fuse_request_init(req);
60 return req;
61 }
62
63 void fuse_request_free(struct fuse_req *req)
64 {
65 kmem_cache_free(fuse_req_cachep, req);
66 }
67
68 static void block_sigs(sigset_t *oldset)
69 {
70 sigset_t mask;
71
72 siginitsetinv(&mask, sigmask(SIGKILL));
73 sigprocmask(SIG_BLOCK, &mask, oldset);
74 }
75
76 static void restore_sigs(sigset_t *oldset)
77 {
78 sigprocmask(SIG_SETMASK, oldset, NULL);
79 }
80
81 static void __fuse_get_request(struct fuse_req *req)
82 {
83 atomic_inc(&req->count);
84 }
85
86 /* Must be called with > 1 refcount */
87 static void __fuse_put_request(struct fuse_req *req)
88 {
89 BUG_ON(atomic_read(&req->count) < 2);
90 atomic_dec(&req->count);
91 }
92
93 static void fuse_req_init_context(struct fuse_req *req)
94 {
95 req->in.h.uid = current_fsuid();
96 req->in.h.gid = current_fsgid();
97 req->in.h.pid = current->pid;
98 }
99
100 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
101 {
102 struct fuse_req *req;
103 sigset_t oldset;
104 int intr;
105 int err;
106
107 atomic_inc(&fc->num_waiting);
108 block_sigs(&oldset);
109 intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
110 restore_sigs(&oldset);
111 err = -EINTR;
112 if (intr)
113 goto out;
114
115 err = -ENOTCONN;
116 if (!fc->connected)
117 goto out;
118
119 req = fuse_request_alloc();
120 err = -ENOMEM;
121 if (!req)
122 goto out;
123
124 fuse_req_init_context(req);
125 req->waiting = 1;
126 return req;
127
128 out:
129 atomic_dec(&fc->num_waiting);
130 return ERR_PTR(err);
131 }
132 EXPORT_SYMBOL_GPL(fuse_get_req);
133
134 /*
135 * Return request in fuse_file->reserved_req. However that may
136 * currently be in use. If that is the case, wait for it to become
137 * available.
138 */
139 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
140 struct file *file)
141 {
142 struct fuse_req *req = NULL;
143 struct fuse_file *ff = file->private_data;
144
145 do {
146 wait_event(fc->reserved_req_waitq, ff->reserved_req);
147 spin_lock(&fc->lock);
148 if (ff->reserved_req) {
149 req = ff->reserved_req;
150 ff->reserved_req = NULL;
151 get_file(file);
152 req->stolen_file = file;
153 }
154 spin_unlock(&fc->lock);
155 } while (!req);
156
157 return req;
158 }
159
160 /*
161 * Put stolen request back into fuse_file->reserved_req
162 */
163 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
164 {
165 struct file *file = req->stolen_file;
166 struct fuse_file *ff = file->private_data;
167
168 spin_lock(&fc->lock);
169 fuse_request_init(req);
170 BUG_ON(ff->reserved_req);
171 ff->reserved_req = req;
172 wake_up_all(&fc->reserved_req_waitq);
173 spin_unlock(&fc->lock);
174 fput(file);
175 }
176
177 /*
178 * Gets a requests for a file operation, always succeeds
179 *
180 * This is used for sending the FLUSH request, which must get to
181 * userspace, due to POSIX locks which may need to be unlocked.
182 *
183 * If allocation fails due to OOM, use the reserved request in
184 * fuse_file.
185 *
186 * This is very unlikely to deadlock accidentally, since the
187 * filesystem should not have it's own file open. If deadlock is
188 * intentional, it can still be broken by "aborting" the filesystem.
189 */
190 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
191 {
192 struct fuse_req *req;
193
194 atomic_inc(&fc->num_waiting);
195 wait_event(fc->blocked_waitq, !fc->blocked);
196 req = fuse_request_alloc();
197 if (!req)
198 req = get_reserved_req(fc, file);
199
200 fuse_req_init_context(req);
201 req->waiting = 1;
202 return req;
203 }
204
205 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
206 {
207 if (atomic_dec_and_test(&req->count)) {
208 if (req->waiting)
209 atomic_dec(&fc->num_waiting);
210
211 if (req->stolen_file)
212 put_reserved_req(fc, req);
213 else
214 fuse_request_free(req);
215 }
216 }
217 EXPORT_SYMBOL_GPL(fuse_put_request);
218
219 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
220 {
221 unsigned nbytes = 0;
222 unsigned i;
223
224 for (i = 0; i < numargs; i++)
225 nbytes += args[i].size;
226
227 return nbytes;
228 }
229
230 static u64 fuse_get_unique(struct fuse_conn *fc)
231 {
232 fc->reqctr++;
233 /* zero is special */
234 if (fc->reqctr == 0)
235 fc->reqctr = 1;
236
237 return fc->reqctr;
238 }
239
240 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
241 {
242 req->in.h.len = sizeof(struct fuse_in_header) +
243 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
244 list_add_tail(&req->list, &fc->pending);
245 req->state = FUSE_REQ_PENDING;
246 if (!req->waiting) {
247 req->waiting = 1;
248 atomic_inc(&fc->num_waiting);
249 }
250 wake_up(&fc->waitq);
251 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
252 }
253
254 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
255 u64 nodeid, u64 nlookup)
256 {
257 forget->forget_one.nodeid = nodeid;
258 forget->forget_one.nlookup = nlookup;
259
260 spin_lock(&fc->lock);
261 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 spin_unlock(&fc->lock);
266 }
267
268 static void flush_bg_queue(struct fuse_conn *fc)
269 {
270 while (fc->active_background < fc->max_background &&
271 !list_empty(&fc->bg_queue)) {
272 struct fuse_req *req;
273
274 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
275 list_del(&req->list);
276 fc->active_background++;
277 req->in.h.unique = fuse_get_unique(fc);
278 queue_request(fc, req);
279 }
280 }
281
282 /*
283 * This function is called when a request is finished. Either a reply
284 * has arrived or it was aborted (and not yet sent) or some error
285 * occurred during communication with userspace, or the device file
286 * was closed. The requester thread is woken up (if still waiting),
287 * the 'end' callback is called if given, else the reference to the
288 * request is released
289 *
290 * Called with fc->lock, unlocks it
291 */
292 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
293 __releases(fc->lock)
294 {
295 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
296 req->end = NULL;
297 list_del(&req->list);
298 list_del(&req->intr_entry);
299 req->state = FUSE_REQ_FINISHED;
300 if (req->background) {
301 if (fc->num_background == fc->max_background) {
302 fc->blocked = 0;
303 wake_up_all(&fc->blocked_waitq);
304 }
305 if (fc->num_background == fc->congestion_threshold &&
306 fc->connected && fc->bdi_initialized) {
307 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
308 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
309 }
310 fc->num_background--;
311 fc->active_background--;
312 flush_bg_queue(fc);
313 }
314 spin_unlock(&fc->lock);
315 wake_up(&req->waitq);
316 if (end)
317 end(fc, req);
318 fuse_put_request(fc, req);
319 }
320
321 static void wait_answer_interruptible(struct fuse_conn *fc,
322 struct fuse_req *req)
323 __releases(fc->lock)
324 __acquires(fc->lock)
325 {
326 if (signal_pending(current))
327 return;
328
329 spin_unlock(&fc->lock);
330 wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
331 spin_lock(&fc->lock);
332 }
333
334 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
335 {
336 list_add_tail(&req->intr_entry, &fc->interrupts);
337 wake_up(&fc->waitq);
338 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
339 }
340
341 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
342 __releases(fc->lock)
343 __acquires(fc->lock)
344 {
345 if (!fc->no_interrupt) {
346 /* Any signal may interrupt this */
347 wait_answer_interruptible(fc, req);
348
349 if (req->aborted)
350 goto aborted;
351 if (req->state == FUSE_REQ_FINISHED)
352 return;
353
354 req->interrupted = 1;
355 if (req->state == FUSE_REQ_SENT)
356 queue_interrupt(fc, req);
357 }
358
359 if (!req->force) {
360 sigset_t oldset;
361
362 /* Only fatal signals may interrupt this */
363 block_sigs(&oldset);
364 wait_answer_interruptible(fc, req);
365 restore_sigs(&oldset);
366
367 if (req->aborted)
368 goto aborted;
369 if (req->state == FUSE_REQ_FINISHED)
370 return;
371
372 /* Request is not yet in userspace, bail out */
373 if (req->state == FUSE_REQ_PENDING) {
374 list_del(&req->list);
375 __fuse_put_request(req);
376 req->out.h.error = -EINTR;
377 return;
378 }
379 }
380
381 /*
382 * Either request is already in userspace, or it was forced.
383 * Wait it out.
384 */
385 spin_unlock(&fc->lock);
386 wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
387 spin_lock(&fc->lock);
388
389 if (!req->aborted)
390 return;
391
392 aborted:
393 BUG_ON(req->state != FUSE_REQ_FINISHED);
394 if (req->locked) {
395 /* This is uninterruptible sleep, because data is
396 being copied to/from the buffers of req. During
397 locked state, there mustn't be any filesystem
398 operation (e.g. page fault), since that could lead
399 to deadlock */
400 spin_unlock(&fc->lock);
401 wait_event(req->waitq, !req->locked);
402 spin_lock(&fc->lock);
403 }
404 }
405
406 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
407 {
408 req->isreply = 1;
409 spin_lock(&fc->lock);
410 if (!fc->connected)
411 req->out.h.error = -ENOTCONN;
412 else if (fc->conn_error)
413 req->out.h.error = -ECONNREFUSED;
414 else {
415 req->in.h.unique = fuse_get_unique(fc);
416 queue_request(fc, req);
417 /* acquire extra reference, since request is still needed
418 after request_end() */
419 __fuse_get_request(req);
420
421 request_wait_answer(fc, req);
422 }
423 spin_unlock(&fc->lock);
424 }
425 EXPORT_SYMBOL_GPL(fuse_request_send);
426
427 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
428 struct fuse_req *req)
429 {
430 req->background = 1;
431 fc->num_background++;
432 if (fc->num_background == fc->max_background)
433 fc->blocked = 1;
434 if (fc->num_background == fc->congestion_threshold &&
435 fc->bdi_initialized) {
436 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
437 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
438 }
439 list_add_tail(&req->list, &fc->bg_queue);
440 flush_bg_queue(fc);
441 }
442
443 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
444 {
445 spin_lock(&fc->lock);
446 if (fc->connected) {
447 fuse_request_send_nowait_locked(fc, req);
448 spin_unlock(&fc->lock);
449 } else {
450 req->out.h.error = -ENOTCONN;
451 request_end(fc, req);
452 }
453 }
454
455 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
456 {
457 req->isreply = 1;
458 fuse_request_send_nowait(fc, req);
459 }
460 EXPORT_SYMBOL_GPL(fuse_request_send_background);
461
462 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
463 struct fuse_req *req, u64 unique)
464 {
465 int err = -ENODEV;
466
467 req->isreply = 0;
468 req->in.h.unique = unique;
469 spin_lock(&fc->lock);
470 if (fc->connected) {
471 queue_request(fc, req);
472 err = 0;
473 }
474 spin_unlock(&fc->lock);
475
476 return err;
477 }
478
479 /*
480 * Called under fc->lock
481 *
482 * fc->connected must have been checked previously
483 */
484 void fuse_request_send_background_locked(struct fuse_conn *fc,
485 struct fuse_req *req)
486 {
487 req->isreply = 1;
488 fuse_request_send_nowait_locked(fc, req);
489 }
490
491 /*
492 * Lock the request. Up to the next unlock_request() there mustn't be
493 * anything that could cause a page-fault. If the request was already
494 * aborted bail out.
495 */
496 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
497 {
498 int err = 0;
499 if (req) {
500 spin_lock(&fc->lock);
501 if (req->aborted)
502 err = -ENOENT;
503 else
504 req->locked = 1;
505 spin_unlock(&fc->lock);
506 }
507 return err;
508 }
509
510 /*
511 * Unlock request. If it was aborted during being locked, the
512 * requester thread is currently waiting for it to be unlocked, so
513 * wake it up.
514 */
515 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
516 {
517 if (req) {
518 spin_lock(&fc->lock);
519 req->locked = 0;
520 if (req->aborted)
521 wake_up(&req->waitq);
522 spin_unlock(&fc->lock);
523 }
524 }
525
526 struct fuse_copy_state {
527 struct fuse_conn *fc;
528 int write;
529 struct fuse_req *req;
530 const struct iovec *iov;
531 struct pipe_buffer *pipebufs;
532 struct pipe_buffer *currbuf;
533 struct pipe_inode_info *pipe;
534 unsigned long nr_segs;
535 unsigned long seglen;
536 unsigned long addr;
537 struct page *pg;
538 void *mapaddr;
539 void *buf;
540 unsigned len;
541 unsigned move_pages:1;
542 };
543
544 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
545 int write,
546 const struct iovec *iov, unsigned long nr_segs)
547 {
548 memset(cs, 0, sizeof(*cs));
549 cs->fc = fc;
550 cs->write = write;
551 cs->iov = iov;
552 cs->nr_segs = nr_segs;
553 }
554
555 /* Unmap and put previous page of userspace buffer */
556 static void fuse_copy_finish(struct fuse_copy_state *cs)
557 {
558 if (cs->currbuf) {
559 struct pipe_buffer *buf = cs->currbuf;
560
561 if (!cs->write) {
562 buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
563 } else {
564 kunmap(buf->page);
565 buf->len = PAGE_SIZE - cs->len;
566 }
567 cs->currbuf = NULL;
568 cs->mapaddr = NULL;
569 } else if (cs->mapaddr) {
570 kunmap(cs->pg);
571 if (cs->write) {
572 flush_dcache_page(cs->pg);
573 set_page_dirty_lock(cs->pg);
574 }
575 put_page(cs->pg);
576 cs->mapaddr = NULL;
577 }
578 }
579
580 /*
581 * Get another pagefull of userspace buffer, and map it to kernel
582 * address space, and lock request
583 */
584 static int fuse_copy_fill(struct fuse_copy_state *cs)
585 {
586 unsigned long offset;
587 int err;
588
589 unlock_request(cs->fc, cs->req);
590 fuse_copy_finish(cs);
591 if (cs->pipebufs) {
592 struct pipe_buffer *buf = cs->pipebufs;
593
594 if (!cs->write) {
595 err = buf->ops->confirm(cs->pipe, buf);
596 if (err)
597 return err;
598
599 BUG_ON(!cs->nr_segs);
600 cs->currbuf = buf;
601 cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
602 cs->len = buf->len;
603 cs->buf = cs->mapaddr + buf->offset;
604 cs->pipebufs++;
605 cs->nr_segs--;
606 } else {
607 struct page *page;
608
609 if (cs->nr_segs == cs->pipe->buffers)
610 return -EIO;
611
612 page = alloc_page(GFP_HIGHUSER);
613 if (!page)
614 return -ENOMEM;
615
616 buf->page = page;
617 buf->offset = 0;
618 buf->len = 0;
619
620 cs->currbuf = buf;
621 cs->mapaddr = kmap(page);
622 cs->buf = cs->mapaddr;
623 cs->len = PAGE_SIZE;
624 cs->pipebufs++;
625 cs->nr_segs++;
626 }
627 } else {
628 if (!cs->seglen) {
629 BUG_ON(!cs->nr_segs);
630 cs->seglen = cs->iov[0].iov_len;
631 cs->addr = (unsigned long) cs->iov[0].iov_base;
632 cs->iov++;
633 cs->nr_segs--;
634 }
635 err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
636 if (err < 0)
637 return err;
638 BUG_ON(err != 1);
639 offset = cs->addr % PAGE_SIZE;
640 cs->mapaddr = kmap(cs->pg);
641 cs->buf = cs->mapaddr + offset;
642 cs->len = min(PAGE_SIZE - offset, cs->seglen);
643 cs->seglen -= cs->len;
644 cs->addr += cs->len;
645 }
646
647 return lock_request(cs->fc, cs->req);
648 }
649
650 /* Do as much copy to/from userspace buffer as we can */
651 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
652 {
653 unsigned ncpy = min(*size, cs->len);
654 if (val) {
655 if (cs->write)
656 memcpy(cs->buf, *val, ncpy);
657 else
658 memcpy(*val, cs->buf, ncpy);
659 *val += ncpy;
660 }
661 *size -= ncpy;
662 cs->len -= ncpy;
663 cs->buf += ncpy;
664 return ncpy;
665 }
666
667 static int fuse_check_page(struct page *page)
668 {
669 if (page_mapcount(page) ||
670 page->mapping != NULL ||
671 page_count(page) != 1 ||
672 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
673 ~(1 << PG_locked |
674 1 << PG_referenced |
675 1 << PG_uptodate |
676 1 << PG_lru |
677 1 << PG_active |
678 1 << PG_reclaim))) {
679 printk(KERN_WARNING "fuse: trying to steal weird page\n");
680 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);
681 return 1;
682 }
683 return 0;
684 }
685
686 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
687 {
688 int err;
689 struct page *oldpage = *pagep;
690 struct page *newpage;
691 struct pipe_buffer *buf = cs->pipebufs;
692 struct address_space *mapping;
693 pgoff_t index;
694
695 unlock_request(cs->fc, cs->req);
696 fuse_copy_finish(cs);
697
698 err = buf->ops->confirm(cs->pipe, buf);
699 if (err)
700 return err;
701
702 BUG_ON(!cs->nr_segs);
703 cs->currbuf = buf;
704 cs->len = buf->len;
705 cs->pipebufs++;
706 cs->nr_segs--;
707
708 if (cs->len != PAGE_SIZE)
709 goto out_fallback;
710
711 if (buf->ops->steal(cs->pipe, buf) != 0)
712 goto out_fallback;
713
714 newpage = buf->page;
715
716 if (WARN_ON(!PageUptodate(newpage)))
717 return -EIO;
718
719 ClearPageMappedToDisk(newpage);
720
721 if (fuse_check_page(newpage) != 0)
722 goto out_fallback_unlock;
723
724 mapping = oldpage->mapping;
725 index = oldpage->index;
726
727 /*
728 * This is a new and locked page, it shouldn't be mapped or
729 * have any special flags on it
730 */
731 if (WARN_ON(page_mapped(oldpage)))
732 goto out_fallback_unlock;
733 if (WARN_ON(page_has_private(oldpage)))
734 goto out_fallback_unlock;
735 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
736 goto out_fallback_unlock;
737 if (WARN_ON(PageMlocked(oldpage)))
738 goto out_fallback_unlock;
739
740 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
741 if (err) {
742 unlock_page(newpage);
743 return err;
744 }
745
746 page_cache_get(newpage);
747
748 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
749 lru_cache_add_file(newpage);
750
751 err = 0;
752 spin_lock(&cs->fc->lock);
753 if (cs->req->aborted)
754 err = -ENOENT;
755 else
756 *pagep = newpage;
757 spin_unlock(&cs->fc->lock);
758
759 if (err) {
760 unlock_page(newpage);
761 page_cache_release(newpage);
762 return err;
763 }
764
765 unlock_page(oldpage);
766 page_cache_release(oldpage);
767 cs->len = 0;
768
769 return 0;
770
771 out_fallback_unlock:
772 unlock_page(newpage);
773 out_fallback:
774 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
775 cs->buf = cs->mapaddr + buf->offset;
776
777 err = lock_request(cs->fc, cs->req);
778 if (err)
779 return err;
780
781 return 1;
782 }
783
784 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
785 unsigned offset, unsigned count)
786 {
787 struct pipe_buffer *buf;
788
789 if (cs->nr_segs == cs->pipe->buffers)
790 return -EIO;
791
792 unlock_request(cs->fc, cs->req);
793 fuse_copy_finish(cs);
794
795 buf = cs->pipebufs;
796 page_cache_get(page);
797 buf->page = page;
798 buf->offset = offset;
799 buf->len = count;
800
801 cs->pipebufs++;
802 cs->nr_segs++;
803 cs->len = 0;
804
805 return 0;
806 }
807
808 /*
809 * Copy a page in the request to/from the userspace buffer. Must be
810 * done atomically
811 */
812 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
813 unsigned offset, unsigned count, int zeroing)
814 {
815 int err;
816 struct page *page = *pagep;
817
818 if (page && zeroing && count < PAGE_SIZE)
819 clear_highpage(page);
820
821 while (count) {
822 if (cs->write && cs->pipebufs && page) {
823 return fuse_ref_page(cs, page, offset, count);
824 } else if (!cs->len) {
825 if (cs->move_pages && page &&
826 offset == 0 && count == PAGE_SIZE) {
827 err = fuse_try_move_page(cs, pagep);
828 if (err <= 0)
829 return err;
830 } else {
831 err = fuse_copy_fill(cs);
832 if (err)
833 return err;
834 }
835 }
836 if (page) {
837 void *mapaddr = kmap_atomic(page, KM_USER0);
838 void *buf = mapaddr + offset;
839 offset += fuse_copy_do(cs, &buf, &count);
840 kunmap_atomic(mapaddr, KM_USER0);
841 } else
842 offset += fuse_copy_do(cs, NULL, &count);
843 }
844 if (page && !cs->write)
845 flush_dcache_page(page);
846 return 0;
847 }
848
849 /* Copy pages in the request to/from userspace buffer */
850 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
851 int zeroing)
852 {
853 unsigned i;
854 struct fuse_req *req = cs->req;
855 unsigned offset = req->page_offset;
856 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
857
858 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
859 int err;
860
861 err = fuse_copy_page(cs, &req->pages[i], offset, count,
862 zeroing);
863 if (err)
864 return err;
865
866 nbytes -= count;
867 count = min(nbytes, (unsigned) PAGE_SIZE);
868 offset = 0;
869 }
870 return 0;
871 }
872
873 /* Copy a single argument in the request to/from userspace buffer */
874 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
875 {
876 while (size) {
877 if (!cs->len) {
878 int err = fuse_copy_fill(cs);
879 if (err)
880 return err;
881 }
882 fuse_copy_do(cs, &val, &size);
883 }
884 return 0;
885 }
886
887 /* Copy request arguments to/from userspace buffer */
888 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
889 unsigned argpages, struct fuse_arg *args,
890 int zeroing)
891 {
892 int err = 0;
893 unsigned i;
894
895 for (i = 0; !err && i < numargs; i++) {
896 struct fuse_arg *arg = &args[i];
897 if (i == numargs - 1 && argpages)
898 err = fuse_copy_pages(cs, arg->size, zeroing);
899 else
900 err = fuse_copy_one(cs, arg->value, arg->size);
901 }
902 return err;
903 }
904
905 static int forget_pending(struct fuse_conn *fc)
906 {
907 return fc->forget_list_head.next != NULL;
908 }
909
910 static int request_pending(struct fuse_conn *fc)
911 {
912 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
913 forget_pending(fc);
914 }
915
916 /* Wait until a request is available on the pending list */
917 static void request_wait(struct fuse_conn *fc)
918 __releases(fc->lock)
919 __acquires(fc->lock)
920 {
921 DECLARE_WAITQUEUE(wait, current);
922
923 add_wait_queue_exclusive(&fc->waitq, &wait);
924 while (fc->connected && !request_pending(fc)) {
925 set_current_state(TASK_INTERRUPTIBLE);
926 if (signal_pending(current))
927 break;
928
929 spin_unlock(&fc->lock);
930 schedule();
931 spin_lock(&fc->lock);
932 }
933 set_current_state(TASK_RUNNING);
934 remove_wait_queue(&fc->waitq, &wait);
935 }
936
937 /*
938 * Transfer an interrupt request to userspace
939 *
940 * Unlike other requests this is assembled on demand, without a need
941 * to allocate a separate fuse_req structure.
942 *
943 * Called with fc->lock held, releases it
944 */
945 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
946 size_t nbytes, struct fuse_req *req)
947 __releases(fc->lock)
948 {
949 struct fuse_in_header ih;
950 struct fuse_interrupt_in arg;
951 unsigned reqsize = sizeof(ih) + sizeof(arg);
952 int err;
953
954 list_del_init(&req->intr_entry);
955 req->intr_unique = fuse_get_unique(fc);
956 memset(&ih, 0, sizeof(ih));
957 memset(&arg, 0, sizeof(arg));
958 ih.len = reqsize;
959 ih.opcode = FUSE_INTERRUPT;
960 ih.unique = req->intr_unique;
961 arg.unique = req->in.h.unique;
962
963 spin_unlock(&fc->lock);
964 if (nbytes < reqsize)
965 return -EINVAL;
966
967 err = fuse_copy_one(cs, &ih, sizeof(ih));
968 if (!err)
969 err = fuse_copy_one(cs, &arg, sizeof(arg));
970 fuse_copy_finish(cs);
971
972 return err ? err : reqsize;
973 }
974
975 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
976 unsigned max,
977 unsigned *countp)
978 {
979 struct fuse_forget_link *head = fc->forget_list_head.next;
980 struct fuse_forget_link **newhead = &head;
981 unsigned count;
982
983 for (count = 0; *newhead != NULL && count < max; count++)
984 newhead = &(*newhead)->next;
985
986 fc->forget_list_head.next = *newhead;
987 *newhead = NULL;
988 if (fc->forget_list_head.next == NULL)
989 fc->forget_list_tail = &fc->forget_list_head;
990
991 if (countp != NULL)
992 *countp = count;
993
994 return head;
995 }
996
997 static int fuse_read_single_forget(struct fuse_conn *fc,
998 struct fuse_copy_state *cs,
999 size_t nbytes)
1000 __releases(fc->lock)
1001 {
1002 int err;
1003 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1004 struct fuse_forget_in arg = {
1005 .nlookup = forget->forget_one.nlookup,
1006 };
1007 struct fuse_in_header ih = {
1008 .opcode = FUSE_FORGET,
1009 .nodeid = forget->forget_one.nodeid,
1010 .unique = fuse_get_unique(fc),
1011 .len = sizeof(ih) + sizeof(arg),
1012 };
1013
1014 spin_unlock(&fc->lock);
1015 kfree(forget);
1016 if (nbytes < ih.len)
1017 return -EINVAL;
1018
1019 err = fuse_copy_one(cs, &ih, sizeof(ih));
1020 if (!err)
1021 err = fuse_copy_one(cs, &arg, sizeof(arg));
1022 fuse_copy_finish(cs);
1023
1024 if (err)
1025 return err;
1026
1027 return ih.len;
1028 }
1029
1030 static int fuse_read_batch_forget(struct fuse_conn *fc,
1031 struct fuse_copy_state *cs, size_t nbytes)
1032 __releases(fc->lock)
1033 {
1034 int err;
1035 unsigned max_forgets;
1036 unsigned count;
1037 struct fuse_forget_link *head;
1038 struct fuse_batch_forget_in arg = { .count = 0 };
1039 struct fuse_in_header ih = {
1040 .opcode = FUSE_BATCH_FORGET,
1041 .unique = fuse_get_unique(fc),
1042 .len = sizeof(ih) + sizeof(arg),
1043 };
1044
1045 if (nbytes < ih.len) {
1046 spin_unlock(&fc->lock);
1047 return -EINVAL;
1048 }
1049
1050 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1051 head = dequeue_forget(fc, max_forgets, &count);
1052 spin_unlock(&fc->lock);
1053
1054 arg.count = count;
1055 ih.len += count * sizeof(struct fuse_forget_one);
1056 err = fuse_copy_one(cs, &ih, sizeof(ih));
1057 if (!err)
1058 err = fuse_copy_one(cs, &arg, sizeof(arg));
1059
1060 while (head) {
1061 struct fuse_forget_link *forget = head;
1062
1063 if (!err) {
1064 err = fuse_copy_one(cs, &forget->forget_one,
1065 sizeof(forget->forget_one));
1066 }
1067 head = forget->next;
1068 kfree(forget);
1069 }
1070
1071 fuse_copy_finish(cs);
1072
1073 if (err)
1074 return err;
1075
1076 return ih.len;
1077 }
1078
1079 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1080 size_t nbytes)
1081 __releases(fc->lock)
1082 {
1083 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1084 return fuse_read_single_forget(fc, cs, nbytes);
1085 else
1086 return fuse_read_batch_forget(fc, cs, nbytes);
1087 }
1088
1089 /*
1090 * Read a single request into the userspace filesystem's buffer. This
1091 * function waits until a request is available, then removes it from
1092 * the pending list and copies request data to userspace buffer. If
1093 * no reply is needed (FORGET) or request has been aborted or there
1094 * was an error during the copying then it's finished by calling
1095 * request_end(). Otherwise add it to the processing list, and set
1096 * the 'sent' flag.
1097 */
1098 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1099 struct fuse_copy_state *cs, size_t nbytes)
1100 {
1101 int err;
1102 struct fuse_req *req;
1103 struct fuse_in *in;
1104 unsigned reqsize;
1105
1106 restart:
1107 spin_lock(&fc->lock);
1108 err = -EAGAIN;
1109 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1110 !request_pending(fc))
1111 goto err_unlock;
1112
1113 request_wait(fc);
1114 err = -ENODEV;
1115 if (!fc->connected)
1116 goto err_unlock;
1117 err = -ERESTARTSYS;
1118 if (!request_pending(fc))
1119 goto err_unlock;
1120
1121 if (!list_empty(&fc->interrupts)) {
1122 req = list_entry(fc->interrupts.next, struct fuse_req,
1123 intr_entry);
1124 return fuse_read_interrupt(fc, cs, nbytes, req);
1125 }
1126
1127 if (forget_pending(fc)) {
1128 if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1129 return fuse_read_forget(fc, cs, nbytes);
1130
1131 if (fc->forget_batch <= -8)
1132 fc->forget_batch = 16;
1133 }
1134
1135 req = list_entry(fc->pending.next, struct fuse_req, list);
1136 req->state = FUSE_REQ_READING;
1137 list_move(&req->list, &fc->io);
1138
1139 in = &req->in;
1140 reqsize = in->h.len;
1141 /* If request is too large, reply with an error and restart the read */
1142 if (nbytes < reqsize) {
1143 req->out.h.error = -EIO;
1144 /* SETXATTR is special, since it may contain too large data */
1145 if (in->h.opcode == FUSE_SETXATTR)
1146 req->out.h.error = -E2BIG;
1147 request_end(fc, req);
1148 goto restart;
1149 }
1150 spin_unlock(&fc->lock);
1151 cs->req = req;
1152 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1153 if (!err)
1154 err = fuse_copy_args(cs, in->numargs, in->argpages,
1155 (struct fuse_arg *) in->args, 0);
1156 fuse_copy_finish(cs);
1157 spin_lock(&fc->lock);
1158 req->locked = 0;
1159 if (req->aborted) {
1160 request_end(fc, req);
1161 return -ENODEV;
1162 }
1163 if (err) {
1164 req->out.h.error = -EIO;
1165 request_end(fc, req);
1166 return err;
1167 }
1168 if (!req->isreply)
1169 request_end(fc, req);
1170 else {
1171 req->state = FUSE_REQ_SENT;
1172 list_move_tail(&req->list, &fc->processing);
1173 if (req->interrupted)
1174 queue_interrupt(fc, req);
1175 spin_unlock(&fc->lock);
1176 }
1177 return reqsize;
1178
1179 err_unlock:
1180 spin_unlock(&fc->lock);
1181 return err;
1182 }
1183
1184 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1185 unsigned long nr_segs, loff_t pos)
1186 {
1187 struct fuse_copy_state cs;
1188 struct file *file = iocb->ki_filp;
1189 struct fuse_conn *fc = fuse_get_conn(file);
1190 if (!fc)
1191 return -EPERM;
1192
1193 fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1194
1195 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1196 }
1197
1198 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1199 struct pipe_buffer *buf)
1200 {
1201 return 1;
1202 }
1203
1204 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1205 .can_merge = 0,
1206 .map = generic_pipe_buf_map,
1207 .unmap = generic_pipe_buf_unmap,
1208 .confirm = generic_pipe_buf_confirm,
1209 .release = generic_pipe_buf_release,
1210 .steal = fuse_dev_pipe_buf_steal,
1211 .get = generic_pipe_buf_get,
1212 };
1213
1214 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1215 struct pipe_inode_info *pipe,
1216 size_t len, unsigned int flags)
1217 {
1218 int ret;
1219 int page_nr = 0;
1220 int do_wakeup = 0;
1221 struct pipe_buffer *bufs;
1222 struct fuse_copy_state cs;
1223 struct fuse_conn *fc = fuse_get_conn(in);
1224 if (!fc)
1225 return -EPERM;
1226
1227 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1228 if (!bufs)
1229 return -ENOMEM;
1230
1231 fuse_copy_init(&cs, fc, 1, NULL, 0);
1232 cs.pipebufs = bufs;
1233 cs.pipe = pipe;
1234 ret = fuse_dev_do_read(fc, in, &cs, len);
1235 if (ret < 0)
1236 goto out;
1237
1238 ret = 0;
1239 pipe_lock(pipe);
1240
1241 if (!pipe->readers) {
1242 send_sig(SIGPIPE, current, 0);
1243 if (!ret)
1244 ret = -EPIPE;
1245 goto out_unlock;
1246 }
1247
1248 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1249 ret = -EIO;
1250 goto out_unlock;
1251 }
1252
1253 while (page_nr < cs.nr_segs) {
1254 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1255 struct pipe_buffer *buf = pipe->bufs + newbuf;
1256
1257 buf->page = bufs[page_nr].page;
1258 buf->offset = bufs[page_nr].offset;
1259 buf->len = bufs[page_nr].len;
1260 buf->ops = &fuse_dev_pipe_buf_ops;
1261
1262 pipe->nrbufs++;
1263 page_nr++;
1264 ret += buf->len;
1265
1266 if (pipe->inode)
1267 do_wakeup = 1;
1268 }
1269
1270 out_unlock:
1271 pipe_unlock(pipe);
1272
1273 if (do_wakeup) {
1274 smp_mb();
1275 if (waitqueue_active(&pipe->wait))
1276 wake_up_interruptible(&pipe->wait);
1277 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1278 }
1279
1280 out:
1281 for (; page_nr < cs.nr_segs; page_nr++)
1282 page_cache_release(bufs[page_nr].page);
1283
1284 kfree(bufs);
1285 return ret;
1286 }
1287
1288 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1289 struct fuse_copy_state *cs)
1290 {
1291 struct fuse_notify_poll_wakeup_out outarg;
1292 int err = -EINVAL;
1293
1294 if (size != sizeof(outarg))
1295 goto err;
1296
1297 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1298 if (err)
1299 goto err;
1300
1301 fuse_copy_finish(cs);
1302 return fuse_notify_poll_wakeup(fc, &outarg);
1303
1304 err:
1305 fuse_copy_finish(cs);
1306 return err;
1307 }
1308
1309 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1310 struct fuse_copy_state *cs)
1311 {
1312 struct fuse_notify_inval_inode_out outarg;
1313 int err = -EINVAL;
1314
1315 if (size != sizeof(outarg))
1316 goto err;
1317
1318 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1319 if (err)
1320 goto err;
1321 fuse_copy_finish(cs);
1322
1323 down_read(&fc->killsb);
1324 err = -ENOENT;
1325 if (fc->sb) {
1326 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1327 outarg.off, outarg.len);
1328 }
1329 up_read(&fc->killsb);
1330 return err;
1331
1332 err:
1333 fuse_copy_finish(cs);
1334 return err;
1335 }
1336
1337 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1338 struct fuse_copy_state *cs)
1339 {
1340 struct fuse_notify_inval_entry_out outarg;
1341 int err = -ENOMEM;
1342 char *buf;
1343 struct qstr name;
1344
1345 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1346 if (!buf)
1347 goto err;
1348
1349 err = -EINVAL;
1350 if (size < sizeof(outarg))
1351 goto err;
1352
1353 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1354 if (err)
1355 goto err;
1356
1357 err = -ENAMETOOLONG;
1358 if (outarg.namelen > FUSE_NAME_MAX)
1359 goto err;
1360
1361 err = -EINVAL;
1362 if (size != sizeof(outarg) + outarg.namelen + 1)
1363 goto err;
1364
1365 name.name = buf;
1366 name.len = outarg.namelen;
1367 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1368 if (err)
1369 goto err;
1370 fuse_copy_finish(cs);
1371 buf[outarg.namelen] = 0;
1372 name.hash = full_name_hash(name.name, name.len);
1373
1374 down_read(&fc->killsb);
1375 err = -ENOENT;
1376 if (fc->sb)
1377 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name);
1378 up_read(&fc->killsb);
1379 kfree(buf);
1380 return err;
1381
1382 err:
1383 kfree(buf);
1384 fuse_copy_finish(cs);
1385 return err;
1386 }
1387
1388 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1389 struct fuse_copy_state *cs)
1390 {
1391 struct fuse_notify_store_out outarg;
1392 struct inode *inode;
1393 struct address_space *mapping;
1394 u64 nodeid;
1395 int err;
1396 pgoff_t index;
1397 unsigned int offset;
1398 unsigned int num;
1399 loff_t file_size;
1400 loff_t end;
1401
1402 err = -EINVAL;
1403 if (size < sizeof(outarg))
1404 goto out_finish;
1405
1406 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1407 if (err)
1408 goto out_finish;
1409
1410 err = -EINVAL;
1411 if (size - sizeof(outarg) != outarg.size)
1412 goto out_finish;
1413
1414 nodeid = outarg.nodeid;
1415
1416 down_read(&fc->killsb);
1417
1418 err = -ENOENT;
1419 if (!fc->sb)
1420 goto out_up_killsb;
1421
1422 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1423 if (!inode)
1424 goto out_up_killsb;
1425
1426 mapping = inode->i_mapping;
1427 index = outarg.offset >> PAGE_CACHE_SHIFT;
1428 offset = outarg.offset & ~PAGE_CACHE_MASK;
1429 file_size = i_size_read(inode);
1430 end = outarg.offset + outarg.size;
1431 if (end > file_size) {
1432 file_size = end;
1433 fuse_write_update_size(inode, file_size);
1434 }
1435
1436 num = outarg.size;
1437 while (num) {
1438 struct page *page;
1439 unsigned int this_num;
1440
1441 err = -ENOMEM;
1442 page = find_or_create_page(mapping, index,
1443 mapping_gfp_mask(mapping));
1444 if (!page)
1445 goto out_iput;
1446
1447 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1448 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1449 if (!err && offset == 0 && (num != 0 || file_size == end))
1450 SetPageUptodate(page);
1451 unlock_page(page);
1452 page_cache_release(page);
1453
1454 if (err)
1455 goto out_iput;
1456
1457 num -= this_num;
1458 offset = 0;
1459 index++;
1460 }
1461
1462 err = 0;
1463
1464 out_iput:
1465 iput(inode);
1466 out_up_killsb:
1467 up_read(&fc->killsb);
1468 out_finish:
1469 fuse_copy_finish(cs);
1470 return err;
1471 }
1472
1473 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1474 {
1475 release_pages(req->pages, req->num_pages, 0);
1476 }
1477
1478 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1479 struct fuse_notify_retrieve_out *outarg)
1480 {
1481 int err;
1482 struct address_space *mapping = inode->i_mapping;
1483 struct fuse_req *req;
1484 pgoff_t index;
1485 loff_t file_size;
1486 unsigned int num;
1487 unsigned int offset;
1488 size_t total_len = 0;
1489
1490 req = fuse_get_req(fc);
1491 if (IS_ERR(req))
1492 return PTR_ERR(req);
1493
1494 offset = outarg->offset & ~PAGE_CACHE_MASK;
1495
1496 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1497 req->in.h.nodeid = outarg->nodeid;
1498 req->in.numargs = 2;
1499 req->in.argpages = 1;
1500 req->page_offset = offset;
1501 req->end = fuse_retrieve_end;
1502
1503 index = outarg->offset >> PAGE_CACHE_SHIFT;
1504 file_size = i_size_read(inode);
1505 num = outarg->size;
1506 if (outarg->offset > file_size)
1507 num = 0;
1508 else if (outarg->offset + num > file_size)
1509 num = file_size - outarg->offset;
1510
1511 while (num) {
1512 struct page *page;
1513 unsigned int this_num;
1514
1515 page = find_get_page(mapping, index);
1516 if (!page)
1517 break;
1518
1519 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1520 req->pages[req->num_pages] = page;
1521 req->num_pages++;
1522
1523 num -= this_num;
1524 total_len += this_num;
1525 }
1526 req->misc.retrieve_in.offset = outarg->offset;
1527 req->misc.retrieve_in.size = total_len;
1528 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1529 req->in.args[0].value = &req->misc.retrieve_in;
1530 req->in.args[1].size = total_len;
1531
1532 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1533 if (err)
1534 fuse_retrieve_end(fc, req);
1535
1536 return err;
1537 }
1538
1539 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1540 struct fuse_copy_state *cs)
1541 {
1542 struct fuse_notify_retrieve_out outarg;
1543 struct inode *inode;
1544 int err;
1545
1546 err = -EINVAL;
1547 if (size != sizeof(outarg))
1548 goto copy_finish;
1549
1550 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1551 if (err)
1552 goto copy_finish;
1553
1554 fuse_copy_finish(cs);
1555
1556 down_read(&fc->killsb);
1557 err = -ENOENT;
1558 if (fc->sb) {
1559 u64 nodeid = outarg.nodeid;
1560
1561 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1562 if (inode) {
1563 err = fuse_retrieve(fc, inode, &outarg);
1564 iput(inode);
1565 }
1566 }
1567 up_read(&fc->killsb);
1568
1569 return err;
1570
1571 copy_finish:
1572 fuse_copy_finish(cs);
1573 return err;
1574 }
1575
1576 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1577 unsigned int size, struct fuse_copy_state *cs)
1578 {
1579 switch (code) {
1580 case FUSE_NOTIFY_POLL:
1581 return fuse_notify_poll(fc, size, cs);
1582
1583 case FUSE_NOTIFY_INVAL_INODE:
1584 return fuse_notify_inval_inode(fc, size, cs);
1585
1586 case FUSE_NOTIFY_INVAL_ENTRY:
1587 return fuse_notify_inval_entry(fc, size, cs);
1588
1589 case FUSE_NOTIFY_STORE:
1590 return fuse_notify_store(fc, size, cs);
1591
1592 case FUSE_NOTIFY_RETRIEVE:
1593 return fuse_notify_retrieve(fc, size, cs);
1594
1595 default:
1596 fuse_copy_finish(cs);
1597 return -EINVAL;
1598 }
1599 }
1600
1601 /* Look up request on processing list by unique ID */
1602 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1603 {
1604 struct list_head *entry;
1605
1606 list_for_each(entry, &fc->processing) {
1607 struct fuse_req *req;
1608 req = list_entry(entry, struct fuse_req, list);
1609 if (req->in.h.unique == unique || req->intr_unique == unique)
1610 return req;
1611 }
1612 return NULL;
1613 }
1614
1615 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1616 unsigned nbytes)
1617 {
1618 unsigned reqsize = sizeof(struct fuse_out_header);
1619
1620 if (out->h.error)
1621 return nbytes != reqsize ? -EINVAL : 0;
1622
1623 reqsize += len_args(out->numargs, out->args);
1624
1625 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1626 return -EINVAL;
1627 else if (reqsize > nbytes) {
1628 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1629 unsigned diffsize = reqsize - nbytes;
1630 if (diffsize > lastarg->size)
1631 return -EINVAL;
1632 lastarg->size -= diffsize;
1633 }
1634 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1635 out->page_zeroing);
1636 }
1637
1638 /*
1639 * Write a single reply to a request. First the header is copied from
1640 * the write buffer. The request is then searched on the processing
1641 * list by the unique ID found in the header. If found, then remove
1642 * it from the list and copy the rest of the buffer to the request.
1643 * The request is finished by calling request_end()
1644 */
1645 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1646 struct fuse_copy_state *cs, size_t nbytes)
1647 {
1648 int err;
1649 struct fuse_req *req;
1650 struct fuse_out_header oh;
1651
1652 if (nbytes < sizeof(struct fuse_out_header))
1653 return -EINVAL;
1654
1655 err = fuse_copy_one(cs, &oh, sizeof(oh));
1656 if (err)
1657 goto err_finish;
1658
1659 err = -EINVAL;
1660 if (oh.len != nbytes)
1661 goto err_finish;
1662
1663 /*
1664 * Zero oh.unique indicates unsolicited notification message
1665 * and error contains notification code.
1666 */
1667 if (!oh.unique) {
1668 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1669 return err ? err : nbytes;
1670 }
1671
1672 err = -EINVAL;
1673 if (oh.error <= -1000 || oh.error > 0)
1674 goto err_finish;
1675
1676 spin_lock(&fc->lock);
1677 err = -ENOENT;
1678 if (!fc->connected)
1679 goto err_unlock;
1680
1681 req = request_find(fc, oh.unique);
1682 if (!req)
1683 goto err_unlock;
1684
1685 if (req->aborted) {
1686 spin_unlock(&fc->lock);
1687 fuse_copy_finish(cs);
1688 spin_lock(&fc->lock);
1689 request_end(fc, req);
1690 return -ENOENT;
1691 }
1692 /* Is it an interrupt reply? */
1693 if (req->intr_unique == oh.unique) {
1694 err = -EINVAL;
1695 if (nbytes != sizeof(struct fuse_out_header))
1696 goto err_unlock;
1697
1698 if (oh.error == -ENOSYS)
1699 fc->no_interrupt = 1;
1700 else if (oh.error == -EAGAIN)
1701 queue_interrupt(fc, req);
1702
1703 spin_unlock(&fc->lock);
1704 fuse_copy_finish(cs);
1705 return nbytes;
1706 }
1707
1708 req->state = FUSE_REQ_WRITING;
1709 list_move(&req->list, &fc->io);
1710 req->out.h = oh;
1711 req->locked = 1;
1712 cs->req = req;
1713 if (!req->out.page_replace)
1714 cs->move_pages = 0;
1715 spin_unlock(&fc->lock);
1716
1717 err = copy_out_args(cs, &req->out, nbytes);
1718 fuse_copy_finish(cs);
1719
1720 spin_lock(&fc->lock);
1721 req->locked = 0;
1722 if (!err) {
1723 if (req->aborted)
1724 err = -ENOENT;
1725 } else if (!req->aborted)
1726 req->out.h.error = -EIO;
1727 request_end(fc, req);
1728
1729 return err ? err : nbytes;
1730
1731 err_unlock:
1732 spin_unlock(&fc->lock);
1733 err_finish:
1734 fuse_copy_finish(cs);
1735 return err;
1736 }
1737
1738 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1739 unsigned long nr_segs, loff_t pos)
1740 {
1741 struct fuse_copy_state cs;
1742 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1743 if (!fc)
1744 return -EPERM;
1745
1746 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1747
1748 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1749 }
1750
1751 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1752 struct file *out, loff_t *ppos,
1753 size_t len, unsigned int flags)
1754 {
1755 unsigned nbuf;
1756 unsigned idx;
1757 struct pipe_buffer *bufs;
1758 struct fuse_copy_state cs;
1759 struct fuse_conn *fc;
1760 size_t rem;
1761 ssize_t ret;
1762
1763 fc = fuse_get_conn(out);
1764 if (!fc)
1765 return -EPERM;
1766
1767 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1768 if (!bufs)
1769 return -ENOMEM;
1770
1771 pipe_lock(pipe);
1772 nbuf = 0;
1773 rem = 0;
1774 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1775 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1776
1777 ret = -EINVAL;
1778 if (rem < len) {
1779 pipe_unlock(pipe);
1780 goto out;
1781 }
1782
1783 rem = len;
1784 while (rem) {
1785 struct pipe_buffer *ibuf;
1786 struct pipe_buffer *obuf;
1787
1788 BUG_ON(nbuf >= pipe->buffers);
1789 BUG_ON(!pipe->nrbufs);
1790 ibuf = &pipe->bufs[pipe->curbuf];
1791 obuf = &bufs[nbuf];
1792
1793 if (rem >= ibuf->len) {
1794 *obuf = *ibuf;
1795 ibuf->ops = NULL;
1796 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1797 pipe->nrbufs--;
1798 } else {
1799 ibuf->ops->get(pipe, ibuf);
1800 *obuf = *ibuf;
1801 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1802 obuf->len = rem;
1803 ibuf->offset += obuf->len;
1804 ibuf->len -= obuf->len;
1805 }
1806 nbuf++;
1807 rem -= obuf->len;
1808 }
1809 pipe_unlock(pipe);
1810
1811 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1812 cs.pipebufs = bufs;
1813 cs.pipe = pipe;
1814
1815 if (flags & SPLICE_F_MOVE)
1816 cs.move_pages = 1;
1817
1818 ret = fuse_dev_do_write(fc, &cs, len);
1819
1820 for (idx = 0; idx < nbuf; idx++) {
1821 struct pipe_buffer *buf = &bufs[idx];
1822 buf->ops->release(pipe, buf);
1823 }
1824 out:
1825 kfree(bufs);
1826 return ret;
1827 }
1828
1829 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1830 {
1831 unsigned mask = POLLOUT | POLLWRNORM;
1832 struct fuse_conn *fc = fuse_get_conn(file);
1833 if (!fc)
1834 return POLLERR;
1835
1836 poll_wait(file, &fc->waitq, wait);
1837
1838 spin_lock(&fc->lock);
1839 if (!fc->connected)
1840 mask = POLLERR;
1841 else if (request_pending(fc))
1842 mask |= POLLIN | POLLRDNORM;
1843 spin_unlock(&fc->lock);
1844
1845 return mask;
1846 }
1847
1848 /*
1849 * Abort all requests on the given list (pending or processing)
1850 *
1851 * This function releases and reacquires fc->lock
1852 */
1853 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1854 __releases(fc->lock)
1855 __acquires(fc->lock)
1856 {
1857 while (!list_empty(head)) {
1858 struct fuse_req *req;
1859 req = list_entry(head->next, struct fuse_req, list);
1860 req->out.h.error = -ECONNABORTED;
1861 request_end(fc, req);
1862 spin_lock(&fc->lock);
1863 }
1864 }
1865
1866 /*
1867 * Abort requests under I/O
1868 *
1869 * The requests are set to aborted and finished, and the request
1870 * waiter is woken up. This will make request_wait_answer() wait
1871 * until the request is unlocked and then return.
1872 *
1873 * If the request is asynchronous, then the end function needs to be
1874 * called after waiting for the request to be unlocked (if it was
1875 * locked).
1876 */
1877 static void end_io_requests(struct fuse_conn *fc)
1878 __releases(fc->lock)
1879 __acquires(fc->lock)
1880 {
1881 while (!list_empty(&fc->io)) {
1882 struct fuse_req *req =
1883 list_entry(fc->io.next, struct fuse_req, list);
1884 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1885
1886 req->aborted = 1;
1887 req->out.h.error = -ECONNABORTED;
1888 req->state = FUSE_REQ_FINISHED;
1889 list_del_init(&req->list);
1890 wake_up(&req->waitq);
1891 if (end) {
1892 req->end = NULL;
1893 __fuse_get_request(req);
1894 spin_unlock(&fc->lock);
1895 wait_event(req->waitq, !req->locked);
1896 end(fc, req);
1897 fuse_put_request(fc, req);
1898 spin_lock(&fc->lock);
1899 }
1900 }
1901 }
1902
1903 static void end_queued_requests(struct fuse_conn *fc)
1904 __releases(fc->lock)
1905 __acquires(fc->lock)
1906 {
1907 fc->max_background = UINT_MAX;
1908 flush_bg_queue(fc);
1909 end_requests(fc, &fc->pending);
1910 end_requests(fc, &fc->processing);
1911 while (forget_pending(fc))
1912 kfree(dequeue_forget(fc, 1, NULL));
1913 }
1914
1915 static void end_polls(struct fuse_conn *fc)
1916 {
1917 struct rb_node *p;
1918
1919 p = rb_first(&fc->polled_files);
1920
1921 while (p) {
1922 struct fuse_file *ff;
1923 ff = rb_entry(p, struct fuse_file, polled_node);
1924 wake_up_interruptible_all(&ff->poll_wait);
1925
1926 p = rb_next(p);
1927 }
1928 }
1929
1930 /*
1931 * Abort all requests.
1932 *
1933 * Emergency exit in case of a malicious or accidental deadlock, or
1934 * just a hung filesystem.
1935 *
1936 * The same effect is usually achievable through killing the
1937 * filesystem daemon and all users of the filesystem. The exception
1938 * is the combination of an asynchronous request and the tricky
1939 * deadlock (see Documentation/filesystems/fuse.txt).
1940 *
1941 * During the aborting, progression of requests from the pending and
1942 * processing lists onto the io list, and progression of new requests
1943 * onto the pending list is prevented by req->connected being false.
1944 *
1945 * Progression of requests under I/O to the processing list is
1946 * prevented by the req->aborted flag being true for these requests.
1947 * For this reason requests on the io list must be aborted first.
1948 */
1949 void fuse_abort_conn(struct fuse_conn *fc)
1950 {
1951 spin_lock(&fc->lock);
1952 if (fc->connected) {
1953 fc->connected = 0;
1954 fc->blocked = 0;
1955 end_io_requests(fc);
1956 end_queued_requests(fc);
1957 end_polls(fc);
1958 wake_up_all(&fc->waitq);
1959 wake_up_all(&fc->blocked_waitq);
1960 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1961 }
1962 spin_unlock(&fc->lock);
1963 }
1964 EXPORT_SYMBOL_GPL(fuse_abort_conn);
1965
1966 int fuse_dev_release(struct inode *inode, struct file *file)
1967 {
1968 struct fuse_conn *fc = fuse_get_conn(file);
1969 if (fc) {
1970 spin_lock(&fc->lock);
1971 fc->connected = 0;
1972 fc->blocked = 0;
1973 end_queued_requests(fc);
1974 end_polls(fc);
1975 wake_up_all(&fc->blocked_waitq);
1976 spin_unlock(&fc->lock);
1977 fuse_conn_put(fc);
1978 }
1979
1980 return 0;
1981 }
1982 EXPORT_SYMBOL_GPL(fuse_dev_release);
1983
1984 static int fuse_dev_fasync(int fd, struct file *file, int on)
1985 {
1986 struct fuse_conn *fc = fuse_get_conn(file);
1987 if (!fc)
1988 return -EPERM;
1989
1990 /* No locking - fasync_helper does its own locking */
1991 return fasync_helper(fd, file, on, &fc->fasync);
1992 }
1993
1994 const struct file_operations fuse_dev_operations = {
1995 .owner = THIS_MODULE,
1996 .llseek = no_llseek,
1997 .read = do_sync_read,
1998 .aio_read = fuse_dev_read,
1999 .splice_read = fuse_dev_splice_read,
2000 .write = do_sync_write,
2001 .aio_write = fuse_dev_write,
2002 .splice_write = fuse_dev_splice_write,
2003 .poll = fuse_dev_poll,
2004 .release = fuse_dev_release,
2005 .fasync = fuse_dev_fasync,
2006 };
2007 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2008
2009 static struct miscdevice fuse_miscdevice = {
2010 .minor = FUSE_MINOR,
2011 .name = "fuse",
2012 .fops = &fuse_dev_operations,
2013 };
2014
2015 int __init fuse_dev_init(void)
2016 {
2017 int err = -ENOMEM;
2018 fuse_req_cachep = kmem_cache_create("fuse_request",
2019 sizeof(struct fuse_req),
2020 0, 0, NULL);
2021 if (!fuse_req_cachep)
2022 goto out;
2023
2024 err = misc_register(&fuse_miscdevice);
2025 if (err)
2026 goto out_cache_clean;
2027
2028 return 0;
2029
2030 out_cache_clean:
2031 kmem_cache_destroy(fuse_req_cachep);
2032 out:
2033 return err;
2034 }
2035
2036 void fuse_dev_cleanup(void)
2037 {
2038 misc_deregister(&fuse_miscdevice);
2039 kmem_cache_destroy(fuse_req_cachep);
2040 }
linux-next