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autofs4: Add d_manage() dentry operation
[deliverable/linux.git] / fs / fuse / dev.c
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/uio.h>
15 #include <linux/miscdevice.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/slab.h>
19 #include <linux/pipe_fs_i.h>
20 #include <linux/swap.h>
21 #include <linux/splice.h>
22
23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
24 MODULE_ALIAS("devname:fuse");
25
26 static struct kmem_cache *fuse_req_cachep;
27
28 static struct fuse_conn *fuse_get_conn(struct file *file)
29 {
30 /*
31 * Lockless access is OK, because file->private data is set
32 * once during mount and is valid until the file is released.
33 */
34 return file->private_data;
35 }
36
37 static void fuse_request_init(struct fuse_req *req)
38 {
39 memset(req, 0, sizeof(*req));
40 INIT_LIST_HEAD(&req->list);
41 INIT_LIST_HEAD(&req->intr_entry);
42 init_waitqueue_head(&req->waitq);
43 atomic_set(&req->count, 1);
44 }
45
46 struct fuse_req *fuse_request_alloc(void)
47 {
48 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
49 if (req)
50 fuse_request_init(req);
51 return req;
52 }
53 EXPORT_SYMBOL_GPL(fuse_request_alloc);
54
55 struct fuse_req *fuse_request_alloc_nofs(void)
56 {
57 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
58 if (req)
59 fuse_request_init(req);
60 return req;
61 }
62
63 void fuse_request_free(struct fuse_req *req)
64 {
65 kmem_cache_free(fuse_req_cachep, req);
66 }
67
68 static void block_sigs(sigset_t *oldset)
69 {
70 sigset_t mask;
71
72 siginitsetinv(&mask, sigmask(SIGKILL));
73 sigprocmask(SIG_BLOCK, &mask, oldset);
74 }
75
76 static void restore_sigs(sigset_t *oldset)
77 {
78 sigprocmask(SIG_SETMASK, oldset, NULL);
79 }
80
81 static void __fuse_get_request(struct fuse_req *req)
82 {
83 atomic_inc(&req->count);
84 }
85
86 /* Must be called with > 1 refcount */
87 static void __fuse_put_request(struct fuse_req *req)
88 {
89 BUG_ON(atomic_read(&req->count) < 2);
90 atomic_dec(&req->count);
91 }
92
93 static void fuse_req_init_context(struct fuse_req *req)
94 {
95 req->in.h.uid = 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 remove_from_page_cache(oldpage);
741 page_cache_release(oldpage);
742
743 err = add_to_page_cache_locked(newpage, mapping, index, GFP_KERNEL);
744 if (err) {
745 printk(KERN_WARNING "fuse_try_move_page: failed to add page");
746 goto out_fallback_unlock;
747 }
748 page_cache_get(newpage);
749
750 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
751 lru_cache_add_file(newpage);
752
753 err = 0;
754 spin_lock(&cs->fc->lock);
755 if (cs->req->aborted)
756 err = -ENOENT;
757 else
758 *pagep = newpage;
759 spin_unlock(&cs->fc->lock);
760
761 if (err) {
762 unlock_page(newpage);
763 page_cache_release(newpage);
764 return err;
765 }
766
767 unlock_page(oldpage);
768 page_cache_release(oldpage);
769 cs->len = 0;
770
771 return 0;
772
773 out_fallback_unlock:
774 unlock_page(newpage);
775 out_fallback:
776 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
777 cs->buf = cs->mapaddr + buf->offset;
778
779 err = lock_request(cs->fc, cs->req);
780 if (err)
781 return err;
782
783 return 1;
784 }
785
786 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
787 unsigned offset, unsigned count)
788 {
789 struct pipe_buffer *buf;
790
791 if (cs->nr_segs == cs->pipe->buffers)
792 return -EIO;
793
794 unlock_request(cs->fc, cs->req);
795 fuse_copy_finish(cs);
796
797 buf = cs->pipebufs;
798 page_cache_get(page);
799 buf->page = page;
800 buf->offset = offset;
801 buf->len = count;
802
803 cs->pipebufs++;
804 cs->nr_segs++;
805 cs->len = 0;
806
807 return 0;
808 }
809
810 /*
811 * Copy a page in the request to/from the userspace buffer. Must be
812 * done atomically
813 */
814 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
815 unsigned offset, unsigned count, int zeroing)
816 {
817 int err;
818 struct page *page = *pagep;
819
820 if (page && zeroing && count < PAGE_SIZE)
821 clear_highpage(page);
822
823 while (count) {
824 if (cs->write && cs->pipebufs && page) {
825 return fuse_ref_page(cs, page, offset, count);
826 } else if (!cs->len) {
827 if (cs->move_pages && page &&
828 offset == 0 && count == PAGE_SIZE) {
829 err = fuse_try_move_page(cs, pagep);
830 if (err <= 0)
831 return err;
832 } else {
833 err = fuse_copy_fill(cs);
834 if (err)
835 return err;
836 }
837 }
838 if (page) {
839 void *mapaddr = kmap_atomic(page, KM_USER0);
840 void *buf = mapaddr + offset;
841 offset += fuse_copy_do(cs, &buf, &count);
842 kunmap_atomic(mapaddr, KM_USER0);
843 } else
844 offset += fuse_copy_do(cs, NULL, &count);
845 }
846 if (page && !cs->write)
847 flush_dcache_page(page);
848 return 0;
849 }
850
851 /* Copy pages in the request to/from userspace buffer */
852 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
853 int zeroing)
854 {
855 unsigned i;
856 struct fuse_req *req = cs->req;
857 unsigned offset = req->page_offset;
858 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
859
860 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
861 int err;
862
863 err = fuse_copy_page(cs, &req->pages[i], offset, count,
864 zeroing);
865 if (err)
866 return err;
867
868 nbytes -= count;
869 count = min(nbytes, (unsigned) PAGE_SIZE);
870 offset = 0;
871 }
872 return 0;
873 }
874
875 /* Copy a single argument in the request to/from userspace buffer */
876 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
877 {
878 while (size) {
879 if (!cs->len) {
880 int err = fuse_copy_fill(cs);
881 if (err)
882 return err;
883 }
884 fuse_copy_do(cs, &val, &size);
885 }
886 return 0;
887 }
888
889 /* Copy request arguments to/from userspace buffer */
890 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
891 unsigned argpages, struct fuse_arg *args,
892 int zeroing)
893 {
894 int err = 0;
895 unsigned i;
896
897 for (i = 0; !err && i < numargs; i++) {
898 struct fuse_arg *arg = &args[i];
899 if (i == numargs - 1 && argpages)
900 err = fuse_copy_pages(cs, arg->size, zeroing);
901 else
902 err = fuse_copy_one(cs, arg->value, arg->size);
903 }
904 return err;
905 }
906
907 static int forget_pending(struct fuse_conn *fc)
908 {
909 return fc->forget_list_head.next != NULL;
910 }
911
912 static int request_pending(struct fuse_conn *fc)
913 {
914 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
915 forget_pending(fc);
916 }
917
918 /* Wait until a request is available on the pending list */
919 static void request_wait(struct fuse_conn *fc)
920 __releases(fc->lock)
921 __acquires(fc->lock)
922 {
923 DECLARE_WAITQUEUE(wait, current);
924
925 add_wait_queue_exclusive(&fc->waitq, &wait);
926 while (fc->connected && !request_pending(fc)) {
927 set_current_state(TASK_INTERRUPTIBLE);
928 if (signal_pending(current))
929 break;
930
931 spin_unlock(&fc->lock);
932 schedule();
933 spin_lock(&fc->lock);
934 }
935 set_current_state(TASK_RUNNING);
936 remove_wait_queue(&fc->waitq, &wait);
937 }
938
939 /*
940 * Transfer an interrupt request to userspace
941 *
942 * Unlike other requests this is assembled on demand, without a need
943 * to allocate a separate fuse_req structure.
944 *
945 * Called with fc->lock held, releases it
946 */
947 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
948 size_t nbytes, struct fuse_req *req)
949 __releases(fc->lock)
950 {
951 struct fuse_in_header ih;
952 struct fuse_interrupt_in arg;
953 unsigned reqsize = sizeof(ih) + sizeof(arg);
954 int err;
955
956 list_del_init(&req->intr_entry);
957 req->intr_unique = fuse_get_unique(fc);
958 memset(&ih, 0, sizeof(ih));
959 memset(&arg, 0, sizeof(arg));
960 ih.len = reqsize;
961 ih.opcode = FUSE_INTERRUPT;
962 ih.unique = req->intr_unique;
963 arg.unique = req->in.h.unique;
964
965 spin_unlock(&fc->lock);
966 if (nbytes < reqsize)
967 return -EINVAL;
968
969 err = fuse_copy_one(cs, &ih, sizeof(ih));
970 if (!err)
971 err = fuse_copy_one(cs, &arg, sizeof(arg));
972 fuse_copy_finish(cs);
973
974 return err ? err : reqsize;
975 }
976
977 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
978 unsigned max,
979 unsigned *countp)
980 {
981 struct fuse_forget_link *head = fc->forget_list_head.next;
982 struct fuse_forget_link **newhead = &head;
983 unsigned count;
984
985 for (count = 0; *newhead != NULL && count < max; count++)
986 newhead = &(*newhead)->next;
987
988 fc->forget_list_head.next = *newhead;
989 *newhead = NULL;
990 if (fc->forget_list_head.next == NULL)
991 fc->forget_list_tail = &fc->forget_list_head;
992
993 if (countp != NULL)
994 *countp = count;
995
996 return head;
997 }
998
999 static int fuse_read_single_forget(struct fuse_conn *fc,
1000 struct fuse_copy_state *cs,
1001 size_t nbytes)
1002 __releases(fc->lock)
1003 {
1004 int err;
1005 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1006 struct fuse_forget_in arg = {
1007 .nlookup = forget->forget_one.nlookup,
1008 };
1009 struct fuse_in_header ih = {
1010 .opcode = FUSE_FORGET,
1011 .nodeid = forget->forget_one.nodeid,
1012 .unique = fuse_get_unique(fc),
1013 .len = sizeof(ih) + sizeof(arg),
1014 };
1015
1016 spin_unlock(&fc->lock);
1017 kfree(forget);
1018 if (nbytes < ih.len)
1019 return -EINVAL;
1020
1021 err = fuse_copy_one(cs, &ih, sizeof(ih));
1022 if (!err)
1023 err = fuse_copy_one(cs, &arg, sizeof(arg));
1024 fuse_copy_finish(cs);
1025
1026 if (err)
1027 return err;
1028
1029 return ih.len;
1030 }
1031
1032 static int fuse_read_batch_forget(struct fuse_conn *fc,
1033 struct fuse_copy_state *cs, size_t nbytes)
1034 __releases(fc->lock)
1035 {
1036 int err;
1037 unsigned max_forgets;
1038 unsigned count;
1039 struct fuse_forget_link *head;
1040 struct fuse_batch_forget_in arg = { .count = 0 };
1041 struct fuse_in_header ih = {
1042 .opcode = FUSE_BATCH_FORGET,
1043 .unique = fuse_get_unique(fc),
1044 .len = sizeof(ih) + sizeof(arg),
1045 };
1046
1047 if (nbytes < ih.len) {
1048 spin_unlock(&fc->lock);
1049 return -EINVAL;
1050 }
1051
1052 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1053 head = dequeue_forget(fc, max_forgets, &count);
1054 spin_unlock(&fc->lock);
1055
1056 arg.count = count;
1057 ih.len += count * sizeof(struct fuse_forget_one);
1058 err = fuse_copy_one(cs, &ih, sizeof(ih));
1059 if (!err)
1060 err = fuse_copy_one(cs, &arg, sizeof(arg));
1061
1062 while (head) {
1063 struct fuse_forget_link *forget = head;
1064
1065 if (!err) {
1066 err = fuse_copy_one(cs, &forget->forget_one,
1067 sizeof(forget->forget_one));
1068 }
1069 head = forget->next;
1070 kfree(forget);
1071 }
1072
1073 fuse_copy_finish(cs);
1074
1075 if (err)
1076 return err;
1077
1078 return ih.len;
1079 }
1080
1081 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1082 size_t nbytes)
1083 __releases(fc->lock)
1084 {
1085 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1086 return fuse_read_single_forget(fc, cs, nbytes);
1087 else
1088 return fuse_read_batch_forget(fc, cs, nbytes);
1089 }
1090
1091 /*
1092 * Read a single request into the userspace filesystem's buffer. This
1093 * function waits until a request is available, then removes it from
1094 * the pending list and copies request data to userspace buffer. If
1095 * no reply is needed (FORGET) or request has been aborted or there
1096 * was an error during the copying then it's finished by calling
1097 * request_end(). Otherwise add it to the processing list, and set
1098 * the 'sent' flag.
1099 */
1100 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1101 struct fuse_copy_state *cs, size_t nbytes)
1102 {
1103 int err;
1104 struct fuse_req *req;
1105 struct fuse_in *in;
1106 unsigned reqsize;
1107
1108 restart:
1109 spin_lock(&fc->lock);
1110 err = -EAGAIN;
1111 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1112 !request_pending(fc))
1113 goto err_unlock;
1114
1115 request_wait(fc);
1116 err = -ENODEV;
1117 if (!fc->connected)
1118 goto err_unlock;
1119 err = -ERESTARTSYS;
1120 if (!request_pending(fc))
1121 goto err_unlock;
1122
1123 if (!list_empty(&fc->interrupts)) {
1124 req = list_entry(fc->interrupts.next, struct fuse_req,
1125 intr_entry);
1126 return fuse_read_interrupt(fc, cs, nbytes, req);
1127 }
1128
1129 if (forget_pending(fc)) {
1130 if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1131 return fuse_read_forget(fc, cs, nbytes);
1132
1133 if (fc->forget_batch <= -8)
1134 fc->forget_batch = 16;
1135 }
1136
1137 req = list_entry(fc->pending.next, struct fuse_req, list);
1138 req->state = FUSE_REQ_READING;
1139 list_move(&req->list, &fc->io);
1140
1141 in = &req->in;
1142 reqsize = in->h.len;
1143 /* If request is too large, reply with an error and restart the read */
1144 if (nbytes < reqsize) {
1145 req->out.h.error = -EIO;
1146 /* SETXATTR is special, since it may contain too large data */
1147 if (in->h.opcode == FUSE_SETXATTR)
1148 req->out.h.error = -E2BIG;
1149 request_end(fc, req);
1150 goto restart;
1151 }
1152 spin_unlock(&fc->lock);
1153 cs->req = req;
1154 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1155 if (!err)
1156 err = fuse_copy_args(cs, in->numargs, in->argpages,
1157 (struct fuse_arg *) in->args, 0);
1158 fuse_copy_finish(cs);
1159 spin_lock(&fc->lock);
1160 req->locked = 0;
1161 if (req->aborted) {
1162 request_end(fc, req);
1163 return -ENODEV;
1164 }
1165 if (err) {
1166 req->out.h.error = -EIO;
1167 request_end(fc, req);
1168 return err;
1169 }
1170 if (!req->isreply)
1171 request_end(fc, req);
1172 else {
1173 req->state = FUSE_REQ_SENT;
1174 list_move_tail(&req->list, &fc->processing);
1175 if (req->interrupted)
1176 queue_interrupt(fc, req);
1177 spin_unlock(&fc->lock);
1178 }
1179 return reqsize;
1180
1181 err_unlock:
1182 spin_unlock(&fc->lock);
1183 return err;
1184 }
1185
1186 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1187 unsigned long nr_segs, loff_t pos)
1188 {
1189 struct fuse_copy_state cs;
1190 struct file *file = iocb->ki_filp;
1191 struct fuse_conn *fc = fuse_get_conn(file);
1192 if (!fc)
1193 return -EPERM;
1194
1195 fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1196
1197 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1198 }
1199
1200 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1201 struct pipe_buffer *buf)
1202 {
1203 return 1;
1204 }
1205
1206 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1207 .can_merge = 0,
1208 .map = generic_pipe_buf_map,
1209 .unmap = generic_pipe_buf_unmap,
1210 .confirm = generic_pipe_buf_confirm,
1211 .release = generic_pipe_buf_release,
1212 .steal = fuse_dev_pipe_buf_steal,
1213 .get = generic_pipe_buf_get,
1214 };
1215
1216 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1217 struct pipe_inode_info *pipe,
1218 size_t len, unsigned int flags)
1219 {
1220 int ret;
1221 int page_nr = 0;
1222 int do_wakeup = 0;
1223 struct pipe_buffer *bufs;
1224 struct fuse_copy_state cs;
1225 struct fuse_conn *fc = fuse_get_conn(in);
1226 if (!fc)
1227 return -EPERM;
1228
1229 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1230 if (!bufs)
1231 return -ENOMEM;
1232
1233 fuse_copy_init(&cs, fc, 1, NULL, 0);
1234 cs.pipebufs = bufs;
1235 cs.pipe = pipe;
1236 ret = fuse_dev_do_read(fc, in, &cs, len);
1237 if (ret < 0)
1238 goto out;
1239
1240 ret = 0;
1241 pipe_lock(pipe);
1242
1243 if (!pipe->readers) {
1244 send_sig(SIGPIPE, current, 0);
1245 if (!ret)
1246 ret = -EPIPE;
1247 goto out_unlock;
1248 }
1249
1250 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1251 ret = -EIO;
1252 goto out_unlock;
1253 }
1254
1255 while (page_nr < cs.nr_segs) {
1256 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1257 struct pipe_buffer *buf = pipe->bufs + newbuf;
1258
1259 buf->page = bufs[page_nr].page;
1260 buf->offset = bufs[page_nr].offset;
1261 buf->len = bufs[page_nr].len;
1262 buf->ops = &fuse_dev_pipe_buf_ops;
1263
1264 pipe->nrbufs++;
1265 page_nr++;
1266 ret += buf->len;
1267
1268 if (pipe->inode)
1269 do_wakeup = 1;
1270 }
1271
1272 out_unlock:
1273 pipe_unlock(pipe);
1274
1275 if (do_wakeup) {
1276 smp_mb();
1277 if (waitqueue_active(&pipe->wait))
1278 wake_up_interruptible(&pipe->wait);
1279 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1280 }
1281
1282 out:
1283 for (; page_nr < cs.nr_segs; page_nr++)
1284 page_cache_release(bufs[page_nr].page);
1285
1286 kfree(bufs);
1287 return ret;
1288 }
1289
1290 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1291 struct fuse_copy_state *cs)
1292 {
1293 struct fuse_notify_poll_wakeup_out outarg;
1294 int err = -EINVAL;
1295
1296 if (size != sizeof(outarg))
1297 goto err;
1298
1299 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1300 if (err)
1301 goto err;
1302
1303 fuse_copy_finish(cs);
1304 return fuse_notify_poll_wakeup(fc, &outarg);
1305
1306 err:
1307 fuse_copy_finish(cs);
1308 return err;
1309 }
1310
1311 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1312 struct fuse_copy_state *cs)
1313 {
1314 struct fuse_notify_inval_inode_out outarg;
1315 int err = -EINVAL;
1316
1317 if (size != sizeof(outarg))
1318 goto err;
1319
1320 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1321 if (err)
1322 goto err;
1323 fuse_copy_finish(cs);
1324
1325 down_read(&fc->killsb);
1326 err = -ENOENT;
1327 if (fc->sb) {
1328 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1329 outarg.off, outarg.len);
1330 }
1331 up_read(&fc->killsb);
1332 return err;
1333
1334 err:
1335 fuse_copy_finish(cs);
1336 return err;
1337 }
1338
1339 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1340 struct fuse_copy_state *cs)
1341 {
1342 struct fuse_notify_inval_entry_out outarg;
1343 int err = -ENOMEM;
1344 char *buf;
1345 struct qstr name;
1346
1347 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1348 if (!buf)
1349 goto err;
1350
1351 err = -EINVAL;
1352 if (size < sizeof(outarg))
1353 goto err;
1354
1355 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1356 if (err)
1357 goto err;
1358
1359 err = -ENAMETOOLONG;
1360 if (outarg.namelen > FUSE_NAME_MAX)
1361 goto err;
1362
1363 name.name = buf;
1364 name.len = outarg.namelen;
1365 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1366 if (err)
1367 goto err;
1368 fuse_copy_finish(cs);
1369 buf[outarg.namelen] = 0;
1370 name.hash = full_name_hash(name.name, name.len);
1371
1372 down_read(&fc->killsb);
1373 err = -ENOENT;
1374 if (fc->sb)
1375 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name);
1376 up_read(&fc->killsb);
1377 kfree(buf);
1378 return err;
1379
1380 err:
1381 kfree(buf);
1382 fuse_copy_finish(cs);
1383 return err;
1384 }
1385
1386 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1387 struct fuse_copy_state *cs)
1388 {
1389 struct fuse_notify_store_out outarg;
1390 struct inode *inode;
1391 struct address_space *mapping;
1392 u64 nodeid;
1393 int err;
1394 pgoff_t index;
1395 unsigned int offset;
1396 unsigned int num;
1397 loff_t file_size;
1398 loff_t end;
1399
1400 err = -EINVAL;
1401 if (size < sizeof(outarg))
1402 goto out_finish;
1403
1404 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1405 if (err)
1406 goto out_finish;
1407
1408 err = -EINVAL;
1409 if (size - sizeof(outarg) != outarg.size)
1410 goto out_finish;
1411
1412 nodeid = outarg.nodeid;
1413
1414 down_read(&fc->killsb);
1415
1416 err = -ENOENT;
1417 if (!fc->sb)
1418 goto out_up_killsb;
1419
1420 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1421 if (!inode)
1422 goto out_up_killsb;
1423
1424 mapping = inode->i_mapping;
1425 index = outarg.offset >> PAGE_CACHE_SHIFT;
1426 offset = outarg.offset & ~PAGE_CACHE_MASK;
1427 file_size = i_size_read(inode);
1428 end = outarg.offset + outarg.size;
1429 if (end > file_size) {
1430 file_size = end;
1431 fuse_write_update_size(inode, file_size);
1432 }
1433
1434 num = outarg.size;
1435 while (num) {
1436 struct page *page;
1437 unsigned int this_num;
1438
1439 err = -ENOMEM;
1440 page = find_or_create_page(mapping, index,
1441 mapping_gfp_mask(mapping));
1442 if (!page)
1443 goto out_iput;
1444
1445 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1446 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1447 if (!err && offset == 0 && (num != 0 || file_size == end))
1448 SetPageUptodate(page);
1449 unlock_page(page);
1450 page_cache_release(page);
1451
1452 if (err)
1453 goto out_iput;
1454
1455 num -= this_num;
1456 offset = 0;
1457 index++;
1458 }
1459
1460 err = 0;
1461
1462 out_iput:
1463 iput(inode);
1464 out_up_killsb:
1465 up_read(&fc->killsb);
1466 out_finish:
1467 fuse_copy_finish(cs);
1468 return err;
1469 }
1470
1471 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1472 {
1473 release_pages(req->pages, req->num_pages, 0);
1474 }
1475
1476 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1477 struct fuse_notify_retrieve_out *outarg)
1478 {
1479 int err;
1480 struct address_space *mapping = inode->i_mapping;
1481 struct fuse_req *req;
1482 pgoff_t index;
1483 loff_t file_size;
1484 unsigned int num;
1485 unsigned int offset;
1486 size_t total_len = 0;
1487
1488 req = fuse_get_req(fc);
1489 if (IS_ERR(req))
1490 return PTR_ERR(req);
1491
1492 offset = outarg->offset & ~PAGE_CACHE_MASK;
1493
1494 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1495 req->in.h.nodeid = outarg->nodeid;
1496 req->in.numargs = 2;
1497 req->in.argpages = 1;
1498 req->page_offset = offset;
1499 req->end = fuse_retrieve_end;
1500
1501 index = outarg->offset >> PAGE_CACHE_SHIFT;
1502 file_size = i_size_read(inode);
1503 num = outarg->size;
1504 if (outarg->offset > file_size)
1505 num = 0;
1506 else if (outarg->offset + num > file_size)
1507 num = file_size - outarg->offset;
1508
1509 while (num) {
1510 struct page *page;
1511 unsigned int this_num;
1512
1513 page = find_get_page(mapping, index);
1514 if (!page)
1515 break;
1516
1517 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1518 req->pages[req->num_pages] = page;
1519 req->num_pages++;
1520
1521 num -= this_num;
1522 total_len += this_num;
1523 }
1524 req->misc.retrieve_in.offset = outarg->offset;
1525 req->misc.retrieve_in.size = total_len;
1526 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1527 req->in.args[0].value = &req->misc.retrieve_in;
1528 req->in.args[1].size = total_len;
1529
1530 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1531 if (err)
1532 fuse_retrieve_end(fc, req);
1533
1534 return err;
1535 }
1536
1537 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1538 struct fuse_copy_state *cs)
1539 {
1540 struct fuse_notify_retrieve_out outarg;
1541 struct inode *inode;
1542 int err;
1543
1544 err = -EINVAL;
1545 if (size != sizeof(outarg))
1546 goto copy_finish;
1547
1548 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1549 if (err)
1550 goto copy_finish;
1551
1552 fuse_copy_finish(cs);
1553
1554 down_read(&fc->killsb);
1555 err = -ENOENT;
1556 if (fc->sb) {
1557 u64 nodeid = outarg.nodeid;
1558
1559 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1560 if (inode) {
1561 err = fuse_retrieve(fc, inode, &outarg);
1562 iput(inode);
1563 }
1564 }
1565 up_read(&fc->killsb);
1566
1567 return err;
1568
1569 copy_finish:
1570 fuse_copy_finish(cs);
1571 return err;
1572 }
1573
1574 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1575 unsigned int size, struct fuse_copy_state *cs)
1576 {
1577 switch (code) {
1578 case FUSE_NOTIFY_POLL:
1579 return fuse_notify_poll(fc, size, cs);
1580
1581 case FUSE_NOTIFY_INVAL_INODE:
1582 return fuse_notify_inval_inode(fc, size, cs);
1583
1584 case FUSE_NOTIFY_INVAL_ENTRY:
1585 return fuse_notify_inval_entry(fc, size, cs);
1586
1587 case FUSE_NOTIFY_STORE:
1588 return fuse_notify_store(fc, size, cs);
1589
1590 case FUSE_NOTIFY_RETRIEVE:
1591 return fuse_notify_retrieve(fc, size, cs);
1592
1593 default:
1594 fuse_copy_finish(cs);
1595 return -EINVAL;
1596 }
1597 }
1598
1599 /* Look up request on processing list by unique ID */
1600 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1601 {
1602 struct list_head *entry;
1603
1604 list_for_each(entry, &fc->processing) {
1605 struct fuse_req *req;
1606 req = list_entry(entry, struct fuse_req, list);
1607 if (req->in.h.unique == unique || req->intr_unique == unique)
1608 return req;
1609 }
1610 return NULL;
1611 }
1612
1613 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1614 unsigned nbytes)
1615 {
1616 unsigned reqsize = sizeof(struct fuse_out_header);
1617
1618 if (out->h.error)
1619 return nbytes != reqsize ? -EINVAL : 0;
1620
1621 reqsize += len_args(out->numargs, out->args);
1622
1623 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1624 return -EINVAL;
1625 else if (reqsize > nbytes) {
1626 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1627 unsigned diffsize = reqsize - nbytes;
1628 if (diffsize > lastarg->size)
1629 return -EINVAL;
1630 lastarg->size -= diffsize;
1631 }
1632 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1633 out->page_zeroing);
1634 }
1635
1636 /*
1637 * Write a single reply to a request. First the header is copied from
1638 * the write buffer. The request is then searched on the processing
1639 * list by the unique ID found in the header. If found, then remove
1640 * it from the list and copy the rest of the buffer to the request.
1641 * The request is finished by calling request_end()
1642 */
1643 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1644 struct fuse_copy_state *cs, size_t nbytes)
1645 {
1646 int err;
1647 struct fuse_req *req;
1648 struct fuse_out_header oh;
1649
1650 if (nbytes < sizeof(struct fuse_out_header))
1651 return -EINVAL;
1652
1653 err = fuse_copy_one(cs, &oh, sizeof(oh));
1654 if (err)
1655 goto err_finish;
1656
1657 err = -EINVAL;
1658 if (oh.len != nbytes)
1659 goto err_finish;
1660
1661 /*
1662 * Zero oh.unique indicates unsolicited notification message
1663 * and error contains notification code.
1664 */
1665 if (!oh.unique) {
1666 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1667 return err ? err : nbytes;
1668 }
1669
1670 err = -EINVAL;
1671 if (oh.error <= -1000 || oh.error > 0)
1672 goto err_finish;
1673
1674 spin_lock(&fc->lock);
1675 err = -ENOENT;
1676 if (!fc->connected)
1677 goto err_unlock;
1678
1679 req = request_find(fc, oh.unique);
1680 if (!req)
1681 goto err_unlock;
1682
1683 if (req->aborted) {
1684 spin_unlock(&fc->lock);
1685 fuse_copy_finish(cs);
1686 spin_lock(&fc->lock);
1687 request_end(fc, req);
1688 return -ENOENT;
1689 }
1690 /* Is it an interrupt reply? */
1691 if (req->intr_unique == oh.unique) {
1692 err = -EINVAL;
1693 if (nbytes != sizeof(struct fuse_out_header))
1694 goto err_unlock;
1695
1696 if (oh.error == -ENOSYS)
1697 fc->no_interrupt = 1;
1698 else if (oh.error == -EAGAIN)
1699 queue_interrupt(fc, req);
1700
1701 spin_unlock(&fc->lock);
1702 fuse_copy_finish(cs);
1703 return nbytes;
1704 }
1705
1706 req->state = FUSE_REQ_WRITING;
1707 list_move(&req->list, &fc->io);
1708 req->out.h = oh;
1709 req->locked = 1;
1710 cs->req = req;
1711 if (!req->out.page_replace)
1712 cs->move_pages = 0;
1713 spin_unlock(&fc->lock);
1714
1715 err = copy_out_args(cs, &req->out, nbytes);
1716 fuse_copy_finish(cs);
1717
1718 spin_lock(&fc->lock);
1719 req->locked = 0;
1720 if (!err) {
1721 if (req->aborted)
1722 err = -ENOENT;
1723 } else if (!req->aborted)
1724 req->out.h.error = -EIO;
1725 request_end(fc, req);
1726
1727 return err ? err : nbytes;
1728
1729 err_unlock:
1730 spin_unlock(&fc->lock);
1731 err_finish:
1732 fuse_copy_finish(cs);
1733 return err;
1734 }
1735
1736 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1737 unsigned long nr_segs, loff_t pos)
1738 {
1739 struct fuse_copy_state cs;
1740 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1741 if (!fc)
1742 return -EPERM;
1743
1744 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1745
1746 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1747 }
1748
1749 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1750 struct file *out, loff_t *ppos,
1751 size_t len, unsigned int flags)
1752 {
1753 unsigned nbuf;
1754 unsigned idx;
1755 struct pipe_buffer *bufs;
1756 struct fuse_copy_state cs;
1757 struct fuse_conn *fc;
1758 size_t rem;
1759 ssize_t ret;
1760
1761 fc = fuse_get_conn(out);
1762 if (!fc)
1763 return -EPERM;
1764
1765 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1766 if (!bufs)
1767 return -ENOMEM;
1768
1769 pipe_lock(pipe);
1770 nbuf = 0;
1771 rem = 0;
1772 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1773 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1774
1775 ret = -EINVAL;
1776 if (rem < len) {
1777 pipe_unlock(pipe);
1778 goto out;
1779 }
1780
1781 rem = len;
1782 while (rem) {
1783 struct pipe_buffer *ibuf;
1784 struct pipe_buffer *obuf;
1785
1786 BUG_ON(nbuf >= pipe->buffers);
1787 BUG_ON(!pipe->nrbufs);
1788 ibuf = &pipe->bufs[pipe->curbuf];
1789 obuf = &bufs[nbuf];
1790
1791 if (rem >= ibuf->len) {
1792 *obuf = *ibuf;
1793 ibuf->ops = NULL;
1794 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1795 pipe->nrbufs--;
1796 } else {
1797 ibuf->ops->get(pipe, ibuf);
1798 *obuf = *ibuf;
1799 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1800 obuf->len = rem;
1801 ibuf->offset += obuf->len;
1802 ibuf->len -= obuf->len;
1803 }
1804 nbuf++;
1805 rem -= obuf->len;
1806 }
1807 pipe_unlock(pipe);
1808
1809 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1810 cs.pipebufs = bufs;
1811 cs.pipe = pipe;
1812
1813 if (flags & SPLICE_F_MOVE)
1814 cs.move_pages = 1;
1815
1816 ret = fuse_dev_do_write(fc, &cs, len);
1817
1818 for (idx = 0; idx < nbuf; idx++) {
1819 struct pipe_buffer *buf = &bufs[idx];
1820 buf->ops->release(pipe, buf);
1821 }
1822 out:
1823 kfree(bufs);
1824 return ret;
1825 }
1826
1827 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1828 {
1829 unsigned mask = POLLOUT | POLLWRNORM;
1830 struct fuse_conn *fc = fuse_get_conn(file);
1831 if (!fc)
1832 return POLLERR;
1833
1834 poll_wait(file, &fc->waitq, wait);
1835
1836 spin_lock(&fc->lock);
1837 if (!fc->connected)
1838 mask = POLLERR;
1839 else if (request_pending(fc))
1840 mask |= POLLIN | POLLRDNORM;
1841 spin_unlock(&fc->lock);
1842
1843 return mask;
1844 }
1845
1846 /*
1847 * Abort all requests on the given list (pending or processing)
1848 *
1849 * This function releases and reacquires fc->lock
1850 */
1851 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1852 __releases(fc->lock)
1853 __acquires(fc->lock)
1854 {
1855 while (!list_empty(head)) {
1856 struct fuse_req *req;
1857 req = list_entry(head->next, struct fuse_req, list);
1858 req->out.h.error = -ECONNABORTED;
1859 request_end(fc, req);
1860 spin_lock(&fc->lock);
1861 }
1862 }
1863
1864 /*
1865 * Abort requests under I/O
1866 *
1867 * The requests are set to aborted and finished, and the request
1868 * waiter is woken up. This will make request_wait_answer() wait
1869 * until the request is unlocked and then return.
1870 *
1871 * If the request is asynchronous, then the end function needs to be
1872 * called after waiting for the request to be unlocked (if it was
1873 * locked).
1874 */
1875 static void end_io_requests(struct fuse_conn *fc)
1876 __releases(fc->lock)
1877 __acquires(fc->lock)
1878 {
1879 while (!list_empty(&fc->io)) {
1880 struct fuse_req *req =
1881 list_entry(fc->io.next, struct fuse_req, list);
1882 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1883
1884 req->aborted = 1;
1885 req->out.h.error = -ECONNABORTED;
1886 req->state = FUSE_REQ_FINISHED;
1887 list_del_init(&req->list);
1888 wake_up(&req->waitq);
1889 if (end) {
1890 req->end = NULL;
1891 __fuse_get_request(req);
1892 spin_unlock(&fc->lock);
1893 wait_event(req->waitq, !req->locked);
1894 end(fc, req);
1895 fuse_put_request(fc, req);
1896 spin_lock(&fc->lock);
1897 }
1898 }
1899 }
1900
1901 static void end_queued_requests(struct fuse_conn *fc)
1902 __releases(fc->lock)
1903 __acquires(fc->lock)
1904 {
1905 fc->max_background = UINT_MAX;
1906 flush_bg_queue(fc);
1907 end_requests(fc, &fc->pending);
1908 end_requests(fc, &fc->processing);
1909 while (forget_pending(fc))
1910 kfree(dequeue_forget(fc, 1, NULL));
1911 }
1912
1913 /*
1914 * Abort all requests.
1915 *
1916 * Emergency exit in case of a malicious or accidental deadlock, or
1917 * just a hung filesystem.
1918 *
1919 * The same effect is usually achievable through killing the
1920 * filesystem daemon and all users of the filesystem. The exception
1921 * is the combination of an asynchronous request and the tricky
1922 * deadlock (see Documentation/filesystems/fuse.txt).
1923 *
1924 * During the aborting, progression of requests from the pending and
1925 * processing lists onto the io list, and progression of new requests
1926 * onto the pending list is prevented by req->connected being false.
1927 *
1928 * Progression of requests under I/O to the processing list is
1929 * prevented by the req->aborted flag being true for these requests.
1930 * For this reason requests on the io list must be aborted first.
1931 */
1932 void fuse_abort_conn(struct fuse_conn *fc)
1933 {
1934 spin_lock(&fc->lock);
1935 if (fc->connected) {
1936 fc->connected = 0;
1937 fc->blocked = 0;
1938 end_io_requests(fc);
1939 end_queued_requests(fc);
1940 wake_up_all(&fc->waitq);
1941 wake_up_all(&fc->blocked_waitq);
1942 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1943 }
1944 spin_unlock(&fc->lock);
1945 }
1946 EXPORT_SYMBOL_GPL(fuse_abort_conn);
1947
1948 int fuse_dev_release(struct inode *inode, struct file *file)
1949 {
1950 struct fuse_conn *fc = fuse_get_conn(file);
1951 if (fc) {
1952 spin_lock(&fc->lock);
1953 fc->connected = 0;
1954 fc->blocked = 0;
1955 end_queued_requests(fc);
1956 wake_up_all(&fc->blocked_waitq);
1957 spin_unlock(&fc->lock);
1958 fuse_conn_put(fc);
1959 }
1960
1961 return 0;
1962 }
1963 EXPORT_SYMBOL_GPL(fuse_dev_release);
1964
1965 static int fuse_dev_fasync(int fd, struct file *file, int on)
1966 {
1967 struct fuse_conn *fc = fuse_get_conn(file);
1968 if (!fc)
1969 return -EPERM;
1970
1971 /* No locking - fasync_helper does its own locking */
1972 return fasync_helper(fd, file, on, &fc->fasync);
1973 }
1974
1975 const struct file_operations fuse_dev_operations = {
1976 .owner = THIS_MODULE,
1977 .llseek = no_llseek,
1978 .read = do_sync_read,
1979 .aio_read = fuse_dev_read,
1980 .splice_read = fuse_dev_splice_read,
1981 .write = do_sync_write,
1982 .aio_write = fuse_dev_write,
1983 .splice_write = fuse_dev_splice_write,
1984 .poll = fuse_dev_poll,
1985 .release = fuse_dev_release,
1986 .fasync = fuse_dev_fasync,
1987 };
1988 EXPORT_SYMBOL_GPL(fuse_dev_operations);
1989
1990 static struct miscdevice fuse_miscdevice = {
1991 .minor = FUSE_MINOR,
1992 .name = "fuse",
1993 .fops = &fuse_dev_operations,
1994 };
1995
1996 int __init fuse_dev_init(void)
1997 {
1998 int err = -ENOMEM;
1999 fuse_req_cachep = kmem_cache_create("fuse_request",
2000 sizeof(struct fuse_req),
2001 0, 0, NULL);
2002 if (!fuse_req_cachep)
2003 goto out;
2004
2005 err = misc_register(&fuse_miscdevice);
2006 if (err)
2007 goto out_cache_clean;
2008
2009 return 0;
2010
2011 out_cache_clean:
2012 kmem_cache_destroy(fuse_req_cachep);
2013 out:
2014 return err;
2015 }
2016
2017 void fuse_dev_cleanup(void)
2018 {
2019 misc_deregister(&fuse_miscdevice);
2020 kmem_cache_destroy(fuse_req_cachep);
2021 }
Linux kernel - Deliverables
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