?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
ipv6: add support of equal cost multipath (ECMP)
[linux-2.6.git] / fs / fuse / dev.c
blob8c23fa7a91e65cb46ad3907432e4418c7f96ad2d
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 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 struct address_space *mapping;
696 pgoff_t index;
697
698 unlock_request(cs->fc, cs->req);
699 fuse_copy_finish(cs);
700
701 err = buf->ops->confirm(cs->pipe, buf);
702 if (err)
703 return err;
704
705 BUG_ON(!cs->nr_segs);
706 cs->currbuf = buf;
707 cs->len = buf->len;
708 cs->pipebufs++;
709 cs->nr_segs--;
710
711 if (cs->len != PAGE_SIZE)
712 goto out_fallback;
713
714 if (buf->ops->steal(cs->pipe, buf) != 0)
715 goto out_fallback;
716
717 newpage = buf->page;
718
719 if (WARN_ON(!PageUptodate(newpage)))
720 return -EIO;
721
722 ClearPageMappedToDisk(newpage);
723
724 if (fuse_check_page(newpage) != 0)
725 goto out_fallback_unlock;
726
727 mapping = oldpage->mapping;
728 index = oldpage->index;
729
730 /*
731 * This is a new and locked page, it shouldn't be mapped or
732 * have any special flags on it
733 */
734 if (WARN_ON(page_mapped(oldpage)))
735 goto out_fallback_unlock;
736 if (WARN_ON(page_has_private(oldpage)))
737 goto out_fallback_unlock;
738 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
739 goto out_fallback_unlock;
740 if (WARN_ON(PageMlocked(oldpage)))
741 goto out_fallback_unlock;
742
743 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
744 if (err) {
745 unlock_page(newpage);
746 return err;
747 }
748
749 page_cache_get(newpage);
750
751 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
752 lru_cache_add_file(newpage);
753
754 err = 0;
755 spin_lock(&cs->fc->lock);
756 if (cs->req->aborted)
757 err = -ENOENT;
758 else
759 *pagep = newpage;
760 spin_unlock(&cs->fc->lock);
761
762 if (err) {
763 unlock_page(newpage);
764 page_cache_release(newpage);
765 return err;
766 }
767
768 unlock_page(oldpage);
769 page_cache_release(oldpage);
770 cs->len = 0;
771
772 return 0;
773
774 out_fallback_unlock:
775 unlock_page(newpage);
776 out_fallback:
777 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
778 cs->buf = cs->mapaddr + buf->offset;
779
780 err = lock_request(cs->fc, cs->req);
781 if (err)
782 return err;
783
784 return 1;
785 }
786
787 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
788 unsigned offset, unsigned count)
789 {
790 struct pipe_buffer *buf;
791
792 if (cs->nr_segs == cs->pipe->buffers)
793 return -EIO;
794
795 unlock_request(cs->fc, cs->req);
796 fuse_copy_finish(cs);
797
798 buf = cs->pipebufs;
799 page_cache_get(page);
800 buf->page = page;
801 buf->offset = offset;
802 buf->len = count;
803
804 cs->pipebufs++;
805 cs->nr_segs++;
806 cs->len = 0;
807
808 return 0;
809 }
810
811 /*
812 * Copy a page in the request to/from the userspace buffer. Must be
813 * done atomically
814 */
815 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
816 unsigned offset, unsigned count, int zeroing)
817 {
818 int err;
819 struct page *page = *pagep;
820
821 if (page && zeroing && count < PAGE_SIZE)
822 clear_highpage(page);
823
824 while (count) {
825 if (cs->write && cs->pipebufs && page) {
826 return fuse_ref_page(cs, page, offset, count);
827 } else if (!cs->len) {
828 if (cs->move_pages && page &&
829 offset == 0 && count == PAGE_SIZE) {
830 err = fuse_try_move_page(cs, pagep);
831 if (err <= 0)
832 return err;
833 } else {
834 err = fuse_copy_fill(cs);
835 if (err)
836 return err;
837 }
838 }
839 if (page) {
840 void *mapaddr = kmap_atomic(page);
841 void *buf = mapaddr + offset;
842 offset += fuse_copy_do(cs, &buf, &count);
843 kunmap_atomic(mapaddr);
844 } else
845 offset += fuse_copy_do(cs, NULL, &count);
846 }
847 if (page && !cs->write)
848 flush_dcache_page(page);
849 return 0;
850 }
851
852 /* Copy pages in the request to/from userspace buffer */
853 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
854 int zeroing)
855 {
856 unsigned i;
857 struct fuse_req *req = cs->req;
858 unsigned offset = req->page_offset;
859 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
860
861 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
862 int err;
863
864 err = fuse_copy_page(cs, &req->pages[i], offset, count,
865 zeroing);
866 if (err)
867 return err;
868
869 nbytes -= count;
870 count = min(nbytes, (unsigned) PAGE_SIZE);
871 offset = 0;
872 }
873 return 0;
874 }
875
876 /* Copy a single argument in the request to/from userspace buffer */
877 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
878 {
879 while (size) {
880 if (!cs->len) {
881 int err = fuse_copy_fill(cs);
882 if (err)
883 return err;
884 }
885 fuse_copy_do(cs, &val, &size);
886 }
887 return 0;
888 }
889
890 /* Copy request arguments to/from userspace buffer */
891 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
892 unsigned argpages, struct fuse_arg *args,
893 int zeroing)
894 {
895 int err = 0;
896 unsigned i;
897
898 for (i = 0; !err && i < numargs; i++) {
899 struct fuse_arg *arg = &args[i];
900 if (i == numargs - 1 && argpages)
901 err = fuse_copy_pages(cs, arg->size, zeroing);
902 else
903 err = fuse_copy_one(cs, arg->value, arg->size);
904 }
905 return err;
906 }
907
908 static int forget_pending(struct fuse_conn *fc)
909 {
910 return fc->forget_list_head.next != NULL;
911 }
912
913 static int request_pending(struct fuse_conn *fc)
914 {
915 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
916 forget_pending(fc);
917 }
918
919 /* Wait until a request is available on the pending list */
920 static void request_wait(struct fuse_conn *fc)
921 __releases(fc->lock)
922 __acquires(fc->lock)
923 {
924 DECLARE_WAITQUEUE(wait, current);
925
926 add_wait_queue_exclusive(&fc->waitq, &wait);
927 while (fc->connected && !request_pending(fc)) {
928 set_current_state(TASK_INTERRUPTIBLE);
929 if (signal_pending(current))
930 break;
931
932 spin_unlock(&fc->lock);
933 schedule();
934 spin_lock(&fc->lock);
935 }
936 set_current_state(TASK_RUNNING);
937 remove_wait_queue(&fc->waitq, &wait);
938 }
939
940 /*
941 * Transfer an interrupt request to userspace
942 *
943 * Unlike other requests this is assembled on demand, without a need
944 * to allocate a separate fuse_req structure.
945 *
946 * Called with fc->lock held, releases it
947 */
948 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
949 size_t nbytes, struct fuse_req *req)
950 __releases(fc->lock)
951 {
952 struct fuse_in_header ih;
953 struct fuse_interrupt_in arg;
954 unsigned reqsize = sizeof(ih) + sizeof(arg);
955 int err;
956
957 list_del_init(&req->intr_entry);
958 req->intr_unique = fuse_get_unique(fc);
959 memset(&ih, 0, sizeof(ih));
960 memset(&arg, 0, sizeof(arg));
961 ih.len = reqsize;
962 ih.opcode = FUSE_INTERRUPT;
963 ih.unique = req->intr_unique;
964 arg.unique = req->in.h.unique;
965
966 spin_unlock(&fc->lock);
967 if (nbytes < reqsize)
968 return -EINVAL;
969
970 err = fuse_copy_one(cs, &ih, sizeof(ih));
971 if (!err)
972 err = fuse_copy_one(cs, &arg, sizeof(arg));
973 fuse_copy_finish(cs);
974
975 return err ? err : reqsize;
976 }
977
978 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
979 unsigned max,
980 unsigned *countp)
981 {
982 struct fuse_forget_link *head = fc->forget_list_head.next;
983 struct fuse_forget_link **newhead = &head;
984 unsigned count;
985
986 for (count = 0; *newhead != NULL && count < max; count++)
987 newhead = &(*newhead)->next;
988
989 fc->forget_list_head.next = *newhead;
990 *newhead = NULL;
991 if (fc->forget_list_head.next == NULL)
992 fc->forget_list_tail = &fc->forget_list_head;
993
994 if (countp != NULL)
995 *countp = count;
996
997 return head;
998 }
999
1000 static int fuse_read_single_forget(struct fuse_conn *fc,
1001 struct fuse_copy_state *cs,
1002 size_t nbytes)
1003 __releases(fc->lock)
1004 {
1005 int err;
1006 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1007 struct fuse_forget_in arg = {
1008 .nlookup = forget->forget_one.nlookup,
1009 };
1010 struct fuse_in_header ih = {
1011 .opcode = FUSE_FORGET,
1012 .nodeid = forget->forget_one.nodeid,
1013 .unique = fuse_get_unique(fc),
1014 .len = sizeof(ih) + sizeof(arg),
1015 };
1016
1017 spin_unlock(&fc->lock);
1018 kfree(forget);
1019 if (nbytes < ih.len)
1020 return -EINVAL;
1021
1022 err = fuse_copy_one(cs, &ih, sizeof(ih));
1023 if (!err)
1024 err = fuse_copy_one(cs, &arg, sizeof(arg));
1025 fuse_copy_finish(cs);
1026
1027 if (err)
1028 return err;
1029
1030 return ih.len;
1031 }
1032
1033 static int fuse_read_batch_forget(struct fuse_conn *fc,
1034 struct fuse_copy_state *cs, size_t nbytes)
1035 __releases(fc->lock)
1036 {
1037 int err;
1038 unsigned max_forgets;
1039 unsigned count;
1040 struct fuse_forget_link *head;
1041 struct fuse_batch_forget_in arg = { .count = 0 };
1042 struct fuse_in_header ih = {
1043 .opcode = FUSE_BATCH_FORGET,
1044 .unique = fuse_get_unique(fc),
1045 .len = sizeof(ih) + sizeof(arg),
1046 };
1047
1048 if (nbytes < ih.len) {
1049 spin_unlock(&fc->lock);
1050 return -EINVAL;
1051 }
1052
1053 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1054 head = dequeue_forget(fc, max_forgets, &count);
1055 spin_unlock(&fc->lock);
1056
1057 arg.count = count;
1058 ih.len += count * sizeof(struct fuse_forget_one);
1059 err = fuse_copy_one(cs, &ih, sizeof(ih));
1060 if (!err)
1061 err = fuse_copy_one(cs, &arg, sizeof(arg));
1062
1063 while (head) {
1064 struct fuse_forget_link *forget = head;
1065
1066 if (!err) {
1067 err = fuse_copy_one(cs, &forget->forget_one,
1068 sizeof(forget->forget_one));
1069 }
1070 head = forget->next;
1071 kfree(forget);
1072 }
1073
1074 fuse_copy_finish(cs);
1075
1076 if (err)
1077 return err;
1078
1079 return ih.len;
1080 }
1081
1082 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1083 size_t nbytes)
1084 __releases(fc->lock)
1085 {
1086 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1087 return fuse_read_single_forget(fc, cs, nbytes);
1088 else
1089 return fuse_read_batch_forget(fc, cs, nbytes);
1090 }
1091
1092 /*
1093 * Read a single request into the userspace filesystem's buffer. This
1094 * function waits until a request is available, then removes it from
1095 * the pending list and copies request data to userspace buffer. If
1096 * no reply is needed (FORGET) or request has been aborted or there
1097 * was an error during the copying then it's finished by calling
1098 * request_end(). Otherwise add it to the processing list, and set
1099 * the 'sent' flag.
1100 */
1101 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1102 struct fuse_copy_state *cs, size_t nbytes)
1103 {
1104 int err;
1105 struct fuse_req *req;
1106 struct fuse_in *in;
1107 unsigned reqsize;
1108
1109 restart:
1110 spin_lock(&fc->lock);
1111 err = -EAGAIN;
1112 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1113 !request_pending(fc))
1114 goto err_unlock;
1115
1116 request_wait(fc);
1117 err = -ENODEV;
1118 if (!fc->connected)
1119 goto err_unlock;
1120 err = -ERESTARTSYS;
1121 if (!request_pending(fc))
1122 goto err_unlock;
1123
1124 if (!list_empty(&fc->interrupts)) {
1125 req = list_entry(fc->interrupts.next, struct fuse_req,
1126 intr_entry);
1127 return fuse_read_interrupt(fc, cs, nbytes, req);
1128 }
1129
1130 if (forget_pending(fc)) {
1131 if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1132 return fuse_read_forget(fc, cs, nbytes);
1133
1134 if (fc->forget_batch <= -8)
1135 fc->forget_batch = 16;
1136 }
1137
1138 req = list_entry(fc->pending.next, struct fuse_req, list);
1139 req->state = FUSE_REQ_READING;
1140 list_move(&req->list, &fc->io);
1141
1142 in = &req->in;
1143 reqsize = in->h.len;
1144 /* If request is too large, reply with an error and restart the read */
1145 if (nbytes < reqsize) {
1146 req->out.h.error = -EIO;
1147 /* SETXATTR is special, since it may contain too large data */
1148 if (in->h.opcode == FUSE_SETXATTR)
1149 req->out.h.error = -E2BIG;
1150 request_end(fc, req);
1151 goto restart;
1152 }
1153 spin_unlock(&fc->lock);
1154 cs->req = req;
1155 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1156 if (!err)
1157 err = fuse_copy_args(cs, in->numargs, in->argpages,
1158 (struct fuse_arg *) in->args, 0);
1159 fuse_copy_finish(cs);
1160 spin_lock(&fc->lock);
1161 req->locked = 0;
1162 if (req->aborted) {
1163 request_end(fc, req);
1164 return -ENODEV;
1165 }
1166 if (err) {
1167 req->out.h.error = -EIO;
1168 request_end(fc, req);
1169 return err;
1170 }
1171 if (!req->isreply)
1172 request_end(fc, req);
1173 else {
1174 req->state = FUSE_REQ_SENT;
1175 list_move_tail(&req->list, &fc->processing);
1176 if (req->interrupted)
1177 queue_interrupt(fc, req);
1178 spin_unlock(&fc->lock);
1179 }
1180 return reqsize;
1181
1182 err_unlock:
1183 spin_unlock(&fc->lock);
1184 return err;
1185 }
1186
1187 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1188 unsigned long nr_segs, loff_t pos)
1189 {
1190 struct fuse_copy_state cs;
1191 struct file *file = iocb->ki_filp;
1192 struct fuse_conn *fc = fuse_get_conn(file);
1193 if (!fc)
1194 return -EPERM;
1195
1196 fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1197
1198 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1199 }
1200
1201 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1202 struct pipe_buffer *buf)
1203 {
1204 return 1;
1205 }
1206
1207 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1208 .can_merge = 0,
1209 .map = generic_pipe_buf_map,
1210 .unmap = generic_pipe_buf_unmap,
1211 .confirm = generic_pipe_buf_confirm,
1212 .release = generic_pipe_buf_release,
1213 .steal = fuse_dev_pipe_buf_steal,
1214 .get = generic_pipe_buf_get,
1215 };
1216
1217 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1218 struct pipe_inode_info *pipe,
1219 size_t len, unsigned int flags)
1220 {
1221 int ret;
1222 int page_nr = 0;
1223 int do_wakeup = 0;
1224 struct pipe_buffer *bufs;
1225 struct fuse_copy_state cs;
1226 struct fuse_conn *fc = fuse_get_conn(in);
1227 if (!fc)
1228 return -EPERM;
1229
1230 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1231 if (!bufs)
1232 return -ENOMEM;
1233
1234 fuse_copy_init(&cs, fc, 1, NULL, 0);
1235 cs.pipebufs = bufs;
1236 cs.pipe = pipe;
1237 ret = fuse_dev_do_read(fc, in, &cs, len);
1238 if (ret < 0)
1239 goto out;
1240
1241 ret = 0;
1242 pipe_lock(pipe);
1243
1244 if (!pipe->readers) {
1245 send_sig(SIGPIPE, current, 0);
1246 if (!ret)
1247 ret = -EPIPE;
1248 goto out_unlock;
1249 }
1250
1251 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1252 ret = -EIO;
1253 goto out_unlock;
1254 }
1255
1256 while (page_nr < cs.nr_segs) {
1257 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1258 struct pipe_buffer *buf = pipe->bufs + newbuf;
1259
1260 buf->page = bufs[page_nr].page;
1261 buf->offset = bufs[page_nr].offset;
1262 buf->len = bufs[page_nr].len;
1263 buf->ops = &fuse_dev_pipe_buf_ops;
1264
1265 pipe->nrbufs++;
1266 page_nr++;
1267 ret += buf->len;
1268
1269 if (pipe->inode)
1270 do_wakeup = 1;
1271 }
1272
1273 out_unlock:
1274 pipe_unlock(pipe);
1275
1276 if (do_wakeup) {
1277 smp_mb();
1278 if (waitqueue_active(&pipe->wait))
1279 wake_up_interruptible(&pipe->wait);
1280 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1281 }
1282
1283 out:
1284 for (; page_nr < cs.nr_segs; page_nr++)
1285 page_cache_release(bufs[page_nr].page);
1286
1287 kfree(bufs);
1288 return ret;
1289 }
1290
1291 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1292 struct fuse_copy_state *cs)
1293 {
1294 struct fuse_notify_poll_wakeup_out outarg;
1295 int err = -EINVAL;
1296
1297 if (size != sizeof(outarg))
1298 goto err;
1299
1300 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1301 if (err)
1302 goto err;
1303
1304 fuse_copy_finish(cs);
1305 return fuse_notify_poll_wakeup(fc, &outarg);
1306
1307 err:
1308 fuse_copy_finish(cs);
1309 return err;
1310 }
1311
1312 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1313 struct fuse_copy_state *cs)
1314 {
1315 struct fuse_notify_inval_inode_out outarg;
1316 int err = -EINVAL;
1317
1318 if (size != sizeof(outarg))
1319 goto err;
1320
1321 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1322 if (err)
1323 goto err;
1324 fuse_copy_finish(cs);
1325
1326 down_read(&fc->killsb);
1327 err = -ENOENT;
1328 if (fc->sb) {
1329 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1330 outarg.off, outarg.len);
1331 }
1332 up_read(&fc->killsb);
1333 return err;
1334
1335 err:
1336 fuse_copy_finish(cs);
1337 return err;
1338 }
1339
1340 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1341 struct fuse_copy_state *cs)
1342 {
1343 struct fuse_notify_inval_entry_out outarg;
1344 int err = -ENOMEM;
1345 char *buf;
1346 struct qstr name;
1347
1348 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1349 if (!buf)
1350 goto err;
1351
1352 err = -EINVAL;
1353 if (size < sizeof(outarg))
1354 goto err;
1355
1356 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1357 if (err)
1358 goto err;
1359
1360 err = -ENAMETOOLONG;
1361 if (outarg.namelen > FUSE_NAME_MAX)
1362 goto err;
1363
1364 err = -EINVAL;
1365 if (size != sizeof(outarg) + outarg.namelen + 1)
1366 goto err;
1367
1368 name.name = buf;
1369 name.len = outarg.namelen;
1370 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1371 if (err)
1372 goto err;
1373 fuse_copy_finish(cs);
1374 buf[outarg.namelen] = 0;
1375 name.hash = full_name_hash(name.name, name.len);
1376
1377 down_read(&fc->killsb);
1378 err = -ENOENT;
1379 if (fc->sb)
1380 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1381 up_read(&fc->killsb);
1382 kfree(buf);
1383 return err;
1384
1385 err:
1386 kfree(buf);
1387 fuse_copy_finish(cs);
1388 return err;
1389 }
1390
1391 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1392 struct fuse_copy_state *cs)
1393 {
1394 struct fuse_notify_delete_out outarg;
1395 int err = -ENOMEM;
1396 char *buf;
1397 struct qstr name;
1398
1399 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1400 if (!buf)
1401 goto err;
1402
1403 err = -EINVAL;
1404 if (size < sizeof(outarg))
1405 goto err;
1406
1407 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1408 if (err)
1409 goto err;
1410
1411 err = -ENAMETOOLONG;
1412 if (outarg.namelen > FUSE_NAME_MAX)
1413 goto err;
1414
1415 err = -EINVAL;
1416 if (size != sizeof(outarg) + outarg.namelen + 1)
1417 goto err;
1418
1419 name.name = buf;
1420 name.len = outarg.namelen;
1421 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1422 if (err)
1423 goto err;
1424 fuse_copy_finish(cs);
1425 buf[outarg.namelen] = 0;
1426 name.hash = full_name_hash(name.name, name.len);
1427
1428 down_read(&fc->killsb);
1429 err = -ENOENT;
1430 if (fc->sb)
1431 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1432 outarg.child, &name);
1433 up_read(&fc->killsb);
1434 kfree(buf);
1435 return err;
1436
1437 err:
1438 kfree(buf);
1439 fuse_copy_finish(cs);
1440 return err;
1441 }
1442
1443 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1444 struct fuse_copy_state *cs)
1445 {
1446 struct fuse_notify_store_out outarg;
1447 struct inode *inode;
1448 struct address_space *mapping;
1449 u64 nodeid;
1450 int err;
1451 pgoff_t index;
1452 unsigned int offset;
1453 unsigned int num;
1454 loff_t file_size;
1455 loff_t end;
1456
1457 err = -EINVAL;
1458 if (size < sizeof(outarg))
1459 goto out_finish;
1460
1461 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1462 if (err)
1463 goto out_finish;
1464
1465 err = -EINVAL;
1466 if (size - sizeof(outarg) != outarg.size)
1467 goto out_finish;
1468
1469 nodeid = outarg.nodeid;
1470
1471 down_read(&fc->killsb);
1472
1473 err = -ENOENT;
1474 if (!fc->sb)
1475 goto out_up_killsb;
1476
1477 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1478 if (!inode)
1479 goto out_up_killsb;
1480
1481 mapping = inode->i_mapping;
1482 index = outarg.offset >> PAGE_CACHE_SHIFT;
1483 offset = outarg.offset & ~PAGE_CACHE_MASK;
1484 file_size = i_size_read(inode);
1485 end = outarg.offset + outarg.size;
1486 if (end > file_size) {
1487 file_size = end;
1488 fuse_write_update_size(inode, file_size);
1489 }
1490
1491 num = outarg.size;
1492 while (num) {
1493 struct page *page;
1494 unsigned int this_num;
1495
1496 err = -ENOMEM;
1497 page = find_or_create_page(mapping, index,
1498 mapping_gfp_mask(mapping));
1499 if (!page)
1500 goto out_iput;
1501
1502 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1503 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1504 if (!err && offset == 0 && (num != 0 || file_size == end))
1505 SetPageUptodate(page);
1506 unlock_page(page);
1507 page_cache_release(page);
1508
1509 if (err)
1510 goto out_iput;
1511
1512 num -= this_num;
1513 offset = 0;
1514 index++;
1515 }
1516
1517 err = 0;
1518
1519 out_iput:
1520 iput(inode);
1521 out_up_killsb:
1522 up_read(&fc->killsb);
1523 out_finish:
1524 fuse_copy_finish(cs);
1525 return err;
1526 }
1527
1528 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1529 {
1530 release_pages(req->pages, req->num_pages, 0);
1531 }
1532
1533 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1534 struct fuse_notify_retrieve_out *outarg)
1535 {
1536 int err;
1537 struct address_space *mapping = inode->i_mapping;
1538 struct fuse_req *req;
1539 pgoff_t index;
1540 loff_t file_size;
1541 unsigned int num;
1542 unsigned int offset;
1543 size_t total_len = 0;
1544
1545 req = fuse_get_req(fc);
1546 if (IS_ERR(req))
1547 return PTR_ERR(req);
1548
1549 offset = outarg->offset & ~PAGE_CACHE_MASK;
1550
1551 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1552 req->in.h.nodeid = outarg->nodeid;
1553 req->in.numargs = 2;
1554 req->in.argpages = 1;
1555 req->page_offset = offset;
1556 req->end = fuse_retrieve_end;
1557
1558 index = outarg->offset >> PAGE_CACHE_SHIFT;
1559 file_size = i_size_read(inode);
1560 num = outarg->size;
1561 if (outarg->offset > file_size)
1562 num = 0;
1563 else if (outarg->offset + num > file_size)
1564 num = file_size - outarg->offset;
1565
1566 while (num && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
1567 struct page *page;
1568 unsigned int this_num;
1569
1570 page = find_get_page(mapping, index);
1571 if (!page)
1572 break;
1573
1574 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1575 req->pages[req->num_pages] = page;
1576 req->num_pages++;
1577
1578 offset = 0;
1579 num -= this_num;
1580 total_len += this_num;
1581 index++;
1582 }
1583 req->misc.retrieve_in.offset = outarg->offset;
1584 req->misc.retrieve_in.size = total_len;
1585 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1586 req->in.args[0].value = &req->misc.retrieve_in;
1587 req->in.args[1].size = total_len;
1588
1589 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1590 if (err)
1591 fuse_retrieve_end(fc, req);
1592
1593 return err;
1594 }
1595
1596 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1597 struct fuse_copy_state *cs)
1598 {
1599 struct fuse_notify_retrieve_out outarg;
1600 struct inode *inode;
1601 int err;
1602
1603 err = -EINVAL;
1604 if (size != sizeof(outarg))
1605 goto copy_finish;
1606
1607 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1608 if (err)
1609 goto copy_finish;
1610
1611 fuse_copy_finish(cs);
1612
1613 down_read(&fc->killsb);
1614 err = -ENOENT;
1615 if (fc->sb) {
1616 u64 nodeid = outarg.nodeid;
1617
1618 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1619 if (inode) {
1620 err = fuse_retrieve(fc, inode, &outarg);
1621 iput(inode);
1622 }
1623 }
1624 up_read(&fc->killsb);
1625
1626 return err;
1627
1628 copy_finish:
1629 fuse_copy_finish(cs);
1630 return err;
1631 }
1632
1633 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1634 unsigned int size, struct fuse_copy_state *cs)
1635 {
1636 switch (code) {
1637 case FUSE_NOTIFY_POLL:
1638 return fuse_notify_poll(fc, size, cs);
1639
1640 case FUSE_NOTIFY_INVAL_INODE:
1641 return fuse_notify_inval_inode(fc, size, cs);
1642
1643 case FUSE_NOTIFY_INVAL_ENTRY:
1644 return fuse_notify_inval_entry(fc, size, cs);
1645
1646 case FUSE_NOTIFY_STORE:
1647 return fuse_notify_store(fc, size, cs);
1648
1649 case FUSE_NOTIFY_RETRIEVE:
1650 return fuse_notify_retrieve(fc, size, cs);
1651
1652 case FUSE_NOTIFY_DELETE:
1653 return fuse_notify_delete(fc, size, cs);
1654
1655 default:
1656 fuse_copy_finish(cs);
1657 return -EINVAL;
1658 }
1659 }
1660
1661 /* Look up request on processing list by unique ID */
1662 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1663 {
1664 struct list_head *entry;
1665
1666 list_for_each(entry, &fc->processing) {
1667 struct fuse_req *req;
1668 req = list_entry(entry, struct fuse_req, list);
1669 if (req->in.h.unique == unique || req->intr_unique == unique)
1670 return req;
1671 }
1672 return NULL;
1673 }
1674
1675 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1676 unsigned nbytes)
1677 {
1678 unsigned reqsize = sizeof(struct fuse_out_header);
1679
1680 if (out->h.error)
1681 return nbytes != reqsize ? -EINVAL : 0;
1682
1683 reqsize += len_args(out->numargs, out->args);
1684
1685 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1686 return -EINVAL;
1687 else if (reqsize > nbytes) {
1688 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1689 unsigned diffsize = reqsize - nbytes;
1690 if (diffsize > lastarg->size)
1691 return -EINVAL;
1692 lastarg->size -= diffsize;
1693 }
1694 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1695 out->page_zeroing);
1696 }
1697
1698 /*
1699 * Write a single reply to a request. First the header is copied from
1700 * the write buffer. The request is then searched on the processing
1701 * list by the unique ID found in the header. If found, then remove
1702 * it from the list and copy the rest of the buffer to the request.
1703 * The request is finished by calling request_end()
1704 */
1705 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1706 struct fuse_copy_state *cs, size_t nbytes)
1707 {
1708 int err;
1709 struct fuse_req *req;
1710 struct fuse_out_header oh;
1711
1712 if (nbytes < sizeof(struct fuse_out_header))
1713 return -EINVAL;
1714
1715 err = fuse_copy_one(cs, &oh, sizeof(oh));
1716 if (err)
1717 goto err_finish;
1718
1719 err = -EINVAL;
1720 if (oh.len != nbytes)
1721 goto err_finish;
1722
1723 /*
1724 * Zero oh.unique indicates unsolicited notification message
1725 * and error contains notification code.
1726 */
1727 if (!oh.unique) {
1728 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1729 return err ? err : nbytes;
1730 }
1731
1732 err = -EINVAL;
1733 if (oh.error <= -1000 || oh.error > 0)
1734 goto err_finish;
1735
1736 spin_lock(&fc->lock);
1737 err = -ENOENT;
1738 if (!fc->connected)
1739 goto err_unlock;
1740
1741 req = request_find(fc, oh.unique);
1742 if (!req)
1743 goto err_unlock;
1744
1745 if (req->aborted) {
1746 spin_unlock(&fc->lock);
1747 fuse_copy_finish(cs);
1748 spin_lock(&fc->lock);
1749 request_end(fc, req);
1750 return -ENOENT;
1751 }
1752 /* Is it an interrupt reply? */
1753 if (req->intr_unique == oh.unique) {
1754 err = -EINVAL;
1755 if (nbytes != sizeof(struct fuse_out_header))
1756 goto err_unlock;
1757
1758 if (oh.error == -ENOSYS)
1759 fc->no_interrupt = 1;
1760 else if (oh.error == -EAGAIN)
1761 queue_interrupt(fc, req);
1762
1763 spin_unlock(&fc->lock);
1764 fuse_copy_finish(cs);
1765 return nbytes;
1766 }
1767
1768 req->state = FUSE_REQ_WRITING;
1769 list_move(&req->list, &fc->io);
1770 req->out.h = oh;
1771 req->locked = 1;
1772 cs->req = req;
1773 if (!req->out.page_replace)
1774 cs->move_pages = 0;
1775 spin_unlock(&fc->lock);
1776
1777 err = copy_out_args(cs, &req->out, nbytes);
1778 fuse_copy_finish(cs);
1779
1780 spin_lock(&fc->lock);
1781 req->locked = 0;
1782 if (!err) {
1783 if (req->aborted)
1784 err = -ENOENT;
1785 } else if (!req->aborted)
1786 req->out.h.error = -EIO;
1787 request_end(fc, req);
1788
1789 return err ? err : nbytes;
1790
1791 err_unlock:
1792 spin_unlock(&fc->lock);
1793 err_finish:
1794 fuse_copy_finish(cs);
1795 return err;
1796 }
1797
1798 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1799 unsigned long nr_segs, loff_t pos)
1800 {
1801 struct fuse_copy_state cs;
1802 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1803 if (!fc)
1804 return -EPERM;
1805
1806 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1807
1808 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1809 }
1810
1811 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1812 struct file *out, loff_t *ppos,
1813 size_t len, unsigned int flags)
1814 {
1815 unsigned nbuf;
1816 unsigned idx;
1817 struct pipe_buffer *bufs;
1818 struct fuse_copy_state cs;
1819 struct fuse_conn *fc;
1820 size_t rem;
1821 ssize_t ret;
1822
1823 fc = fuse_get_conn(out);
1824 if (!fc)
1825 return -EPERM;
1826
1827 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1828 if (!bufs)
1829 return -ENOMEM;
1830
1831 pipe_lock(pipe);
1832 nbuf = 0;
1833 rem = 0;
1834 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1835 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1836
1837 ret = -EINVAL;
1838 if (rem < len) {
1839 pipe_unlock(pipe);
1840 goto out;
1841 }
1842
1843 rem = len;
1844 while (rem) {
1845 struct pipe_buffer *ibuf;
1846 struct pipe_buffer *obuf;
1847
1848 BUG_ON(nbuf >= pipe->buffers);
1849 BUG_ON(!pipe->nrbufs);
1850 ibuf = &pipe->bufs[pipe->curbuf];
1851 obuf = &bufs[nbuf];
1852
1853 if (rem >= ibuf->len) {
1854 *obuf = *ibuf;
1855 ibuf->ops = NULL;
1856 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1857 pipe->nrbufs--;
1858 } else {
1859 ibuf->ops->get(pipe, ibuf);
1860 *obuf = *ibuf;
1861 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1862 obuf->len = rem;
1863 ibuf->offset += obuf->len;
1864 ibuf->len -= obuf->len;
1865 }
1866 nbuf++;
1867 rem -= obuf->len;
1868 }
1869 pipe_unlock(pipe);
1870
1871 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1872 cs.pipebufs = bufs;
1873 cs.pipe = pipe;
1874
1875 if (flags & SPLICE_F_MOVE)
1876 cs.move_pages = 1;
1877
1878 ret = fuse_dev_do_write(fc, &cs, len);
1879
1880 for (idx = 0; idx < nbuf; idx++) {
1881 struct pipe_buffer *buf = &bufs[idx];
1882 buf->ops->release(pipe, buf);
1883 }
1884 out:
1885 kfree(bufs);
1886 return ret;
1887 }
1888
1889 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1890 {
1891 unsigned mask = POLLOUT | POLLWRNORM;
1892 struct fuse_conn *fc = fuse_get_conn(file);
1893 if (!fc)
1894 return POLLERR;
1895
1896 poll_wait(file, &fc->waitq, wait);
1897
1898 spin_lock(&fc->lock);
1899 if (!fc->connected)
1900 mask = POLLERR;
1901 else if (request_pending(fc))
1902 mask |= POLLIN | POLLRDNORM;
1903 spin_unlock(&fc->lock);
1904
1905 return mask;
1906 }
1907
1908 /*
1909 * Abort all requests on the given list (pending or processing)
1910 *
1911 * This function releases and reacquires fc->lock
1912 */
1913 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1914 __releases(fc->lock)
1915 __acquires(fc->lock)
1916 {
1917 while (!list_empty(head)) {
1918 struct fuse_req *req;
1919 req = list_entry(head->next, struct fuse_req, list);
1920 req->out.h.error = -ECONNABORTED;
1921 request_end(fc, req);
1922 spin_lock(&fc->lock);
1923 }
1924 }
1925
1926 /*
1927 * Abort requests under I/O
1928 *
1929 * The requests are set to aborted and finished, and the request
1930 * waiter is woken up. This will make request_wait_answer() wait
1931 * until the request is unlocked and then return.
1932 *
1933 * If the request is asynchronous, then the end function needs to be
1934 * called after waiting for the request to be unlocked (if it was
1935 * locked).
1936 */
1937 static void end_io_requests(struct fuse_conn *fc)
1938 __releases(fc->lock)
1939 __acquires(fc->lock)
1940 {
1941 while (!list_empty(&fc->io)) {
1942 struct fuse_req *req =
1943 list_entry(fc->io.next, struct fuse_req, list);
1944 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1945
1946 req->aborted = 1;
1947 req->out.h.error = -ECONNABORTED;
1948 req->state = FUSE_REQ_FINISHED;
1949 list_del_init(&req->list);
1950 wake_up(&req->waitq);
1951 if (end) {
1952 req->end = NULL;
1953 __fuse_get_request(req);
1954 spin_unlock(&fc->lock);
1955 wait_event(req->waitq, !req->locked);
1956 end(fc, req);
1957 fuse_put_request(fc, req);
1958 spin_lock(&fc->lock);
1959 }
1960 }
1961 }
1962
1963 static void end_queued_requests(struct fuse_conn *fc)
1964 __releases(fc->lock)
1965 __acquires(fc->lock)
1966 {
1967 fc->max_background = UINT_MAX;
1968 flush_bg_queue(fc);
1969 end_requests(fc, &fc->pending);
1970 end_requests(fc, &fc->processing);
1971 while (forget_pending(fc))
1972 kfree(dequeue_forget(fc, 1, NULL));
1973 }
1974
1975 static void end_polls(struct fuse_conn *fc)
1976 {
1977 struct rb_node *p;
1978
1979 p = rb_first(&fc->polled_files);
1980
1981 while (p) {
1982 struct fuse_file *ff;
1983 ff = rb_entry(p, struct fuse_file, polled_node);
1984 wake_up_interruptible_all(&ff->poll_wait);
1985
1986 p = rb_next(p);
1987 }
1988 }
1989
1990 /*
1991 * Abort all requests.
1992 *
1993 * Emergency exit in case of a malicious or accidental deadlock, or
1994 * just a hung filesystem.
1995 *
1996 * The same effect is usually achievable through killing the
1997 * filesystem daemon and all users of the filesystem. The exception
1998 * is the combination of an asynchronous request and the tricky
1999 * deadlock (see Documentation/filesystems/fuse.txt).
2000 *
2001 * During the aborting, progression of requests from the pending and
2002 * processing lists onto the io list, and progression of new requests
2003 * onto the pending list is prevented by req->connected being false.
2004 *
2005 * Progression of requests under I/O to the processing list is
2006 * prevented by the req->aborted flag being true for these requests.
2007 * For this reason requests on the io list must be aborted first.
2008 */
2009 void fuse_abort_conn(struct fuse_conn *fc)
2010 {
2011 spin_lock(&fc->lock);
2012 if (fc->connected) {
2013 fc->connected = 0;
2014 fc->blocked = 0;
2015 end_io_requests(fc);
2016 end_queued_requests(fc);
2017 end_polls(fc);
2018 wake_up_all(&fc->waitq);
2019 wake_up_all(&fc->blocked_waitq);
2020 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
2021 }
2022 spin_unlock(&fc->lock);
2023 }
2024 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2025
2026 int fuse_dev_release(struct inode *inode, struct file *file)
2027 {
2028 struct fuse_conn *fc = fuse_get_conn(file);
2029 if (fc) {
2030 spin_lock(&fc->lock);
2031 fc->connected = 0;
2032 fc->blocked = 0;
2033 end_queued_requests(fc);
2034 end_polls(fc);
2035 wake_up_all(&fc->blocked_waitq);
2036 spin_unlock(&fc->lock);
2037 fuse_conn_put(fc);
2038 }
2039
2040 return 0;
2041 }
2042 EXPORT_SYMBOL_GPL(fuse_dev_release);
2043
2044 static int fuse_dev_fasync(int fd, struct file *file, int on)
2045 {
2046 struct fuse_conn *fc = fuse_get_conn(file);
2047 if (!fc)
2048 return -EPERM;
2049
2050 /* No locking - fasync_helper does its own locking */
2051 return fasync_helper(fd, file, on, &fc->fasync);
2052 }
2053
2054 const struct file_operations fuse_dev_operations = {
2055 .owner = THIS_MODULE,
2056 .llseek = no_llseek,
2057 .read = do_sync_read,
2058 .aio_read = fuse_dev_read,
2059 .splice_read = fuse_dev_splice_read,
2060 .write = do_sync_write,
2061 .aio_write = fuse_dev_write,
2062 .splice_write = fuse_dev_splice_write,
2063 .poll = fuse_dev_poll,
2064 .release = fuse_dev_release,
2065 .fasync = fuse_dev_fasync,
2066 };
2067 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2068
2069 static struct miscdevice fuse_miscdevice = {
2070 .minor = FUSE_MINOR,
2071 .name = "fuse",
2072 .fops = &fuse_dev_operations,
2073 };
2074
2075 int __init fuse_dev_init(void)
2076 {
2077 int err = -ENOMEM;
2078 fuse_req_cachep = kmem_cache_create("fuse_request",
2079 sizeof(struct fuse_req),
2080 0, 0, NULL);
2081 if (!fuse_req_cachep)
2082 goto out;
2083
2084 err = misc_register(&fuse_miscdevice);
2085 if (err)
2086 goto out_cache_clean;
2087
2088 return 0;
2089
2090 out_cache_clean:
2091 kmem_cache_destroy(fuse_req_cachep);
2092 out:
2093 return err;
2094 }
2095
2096 void fuse_dev_cleanup(void)
2097 {
2098 misc_deregister(&fuse_miscdevice);
2099 kmem_cache_destroy(fuse_req_cachep);
2100 }
Linus' kernel tree