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ipc/mqueue.c: refactor failure handling
[linux-2.6/libata-dev.git] / fs / fuse / dev.c
blob640fc229df10323b6c9fc94b0bda452157bf1ef0
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/uio.h>
15 #include <linux/miscdevice.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/slab.h>
19 #include <linux/pipe_fs_i.h>
20 #include <linux/swap.h>
21 #include <linux/splice.h>
22
23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
24 MODULE_ALIAS("devname:fuse");
25
26 static struct kmem_cache *fuse_req_cachep;
27
28 static struct fuse_conn *fuse_get_conn(struct file *file)
29 {
30 /*
31 * Lockless access is OK, because file->private data is set
32 * once during mount and is valid until the file is released.
33 */
34 return file->private_data;
35 }
36
37 static void fuse_request_init(struct fuse_req *req)
38 {
39 memset(req, 0, sizeof(*req));
40 INIT_LIST_HEAD(&req->list);
41 INIT_LIST_HEAD(&req->intr_entry);
42 init_waitqueue_head(&req->waitq);
43 atomic_set(&req->count, 1);
44 }
45
46 struct fuse_req *fuse_request_alloc(void)
47 {
48 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
49 if (req)
50 fuse_request_init(req);
51 return req;
52 }
53 EXPORT_SYMBOL_GPL(fuse_request_alloc);
54
55 struct fuse_req *fuse_request_alloc_nofs(void)
56 {
57 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
58 if (req)
59 fuse_request_init(req);
60 return req;
61 }
62
63 void fuse_request_free(struct fuse_req *req)
64 {
65 kmem_cache_free(fuse_req_cachep, req);
66 }
67
68 static void block_sigs(sigset_t *oldset)
69 {
70 sigset_t mask;
71
72 siginitsetinv(&mask, sigmask(SIGKILL));
73 sigprocmask(SIG_BLOCK, &mask, oldset);
74 }
75
76 static void restore_sigs(sigset_t *oldset)
77 {
78 sigprocmask(SIG_SETMASK, oldset, NULL);
79 }
80
81 static void __fuse_get_request(struct fuse_req *req)
82 {
83 atomic_inc(&req->count);
84 }
85
86 /* Must be called with > 1 refcount */
87 static void __fuse_put_request(struct fuse_req *req)
88 {
89 BUG_ON(atomic_read(&req->count) < 2);
90 atomic_dec(&req->count);
91 }
92
93 static void fuse_req_init_context(struct fuse_req *req)
94 {
95 req->in.h.uid = current_fsuid();
96 req->in.h.gid = current_fsgid();
97 req->in.h.pid = current->pid;
98 }
99
100 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
101 {
102 struct fuse_req *req;
103 sigset_t oldset;
104 int intr;
105 int err;
106
107 atomic_inc(&fc->num_waiting);
108 block_sigs(&oldset);
109 intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
110 restore_sigs(&oldset);
111 err = -EINTR;
112 if (intr)
113 goto out;
114
115 err = -ENOTCONN;
116 if (!fc->connected)
117 goto out;
118
119 req = fuse_request_alloc();
120 err = -ENOMEM;
121 if (!req)
122 goto out;
123
124 fuse_req_init_context(req);
125 req->waiting = 1;
126 return req;
127
128 out:
129 atomic_dec(&fc->num_waiting);
130 return ERR_PTR(err);
131 }
132 EXPORT_SYMBOL_GPL(fuse_get_req);
133
134 /*
135 * Return request in fuse_file->reserved_req. However that may
136 * currently be in use. If that is the case, wait for it to become
137 * available.
138 */
139 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
140 struct file *file)
141 {
142 struct fuse_req *req = NULL;
143 struct fuse_file *ff = file->private_data;
144
145 do {
146 wait_event(fc->reserved_req_waitq, ff->reserved_req);
147 spin_lock(&fc->lock);
148 if (ff->reserved_req) {
149 req = ff->reserved_req;
150 ff->reserved_req = NULL;
151 get_file(file);
152 req->stolen_file = file;
153 }
154 spin_unlock(&fc->lock);
155 } while (!req);
156
157 return req;
158 }
159
160 /*
161 * Put stolen request back into fuse_file->reserved_req
162 */
163 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
164 {
165 struct file *file = req->stolen_file;
166 struct fuse_file *ff = file->private_data;
167
168 spin_lock(&fc->lock);
169 fuse_request_init(req);
170 BUG_ON(ff->reserved_req);
171 ff->reserved_req = req;
172 wake_up_all(&fc->reserved_req_waitq);
173 spin_unlock(&fc->lock);
174 fput(file);
175 }
176
177 /*
178 * Gets a requests for a file operation, always succeeds
179 *
180 * This is used for sending the FLUSH request, which must get to
181 * userspace, due to POSIX locks which may need to be unlocked.
182 *
183 * If allocation fails due to OOM, use the reserved request in
184 * fuse_file.
185 *
186 * This is very unlikely to deadlock accidentally, since the
187 * filesystem should not have it's own file open. If deadlock is
188 * intentional, it can still be broken by "aborting" the filesystem.
189 */
190 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
191 {
192 struct fuse_req *req;
193
194 atomic_inc(&fc->num_waiting);
195 wait_event(fc->blocked_waitq, !fc->blocked);
196 req = fuse_request_alloc();
197 if (!req)
198 req = get_reserved_req(fc, file);
199
200 fuse_req_init_context(req);
201 req->waiting = 1;
202 return req;
203 }
204
205 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
206 {
207 if (atomic_dec_and_test(&req->count)) {
208 if (req->waiting)
209 atomic_dec(&fc->num_waiting);
210
211 if (req->stolen_file)
212 put_reserved_req(fc, req);
213 else
214 fuse_request_free(req);
215 }
216 }
217 EXPORT_SYMBOL_GPL(fuse_put_request);
218
219 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
220 {
221 unsigned nbytes = 0;
222 unsigned i;
223
224 for (i = 0; i < numargs; i++)
225 nbytes += args[i].size;
226
227 return nbytes;
228 }
229
230 static u64 fuse_get_unique(struct fuse_conn *fc)
231 {
232 fc->reqctr++;
233 /* zero is special */
234 if (fc->reqctr == 0)
235 fc->reqctr = 1;
236
237 return fc->reqctr;
238 }
239
240 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
241 {
242 req->in.h.len = sizeof(struct fuse_in_header) +
243 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
244 list_add_tail(&req->list, &fc->pending);
245 req->state = FUSE_REQ_PENDING;
246 if (!req->waiting) {
247 req->waiting = 1;
248 atomic_inc(&fc->num_waiting);
249 }
250 wake_up(&fc->waitq);
251 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
252 }
253
254 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
255 u64 nodeid, u64 nlookup)
256 {
257 forget->forget_one.nodeid = nodeid;
258 forget->forget_one.nlookup = nlookup;
259
260 spin_lock(&fc->lock);
261 fc->forget_list_tail->next = forget;
262 fc->forget_list_tail = forget;
263 wake_up(&fc->waitq);
264 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
265 spin_unlock(&fc->lock);
266 }
267
268 static void flush_bg_queue(struct fuse_conn *fc)
269 {
270 while (fc->active_background < fc->max_background &&
271 !list_empty(&fc->bg_queue)) {
272 struct fuse_req *req;
273
274 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
275 list_del(&req->list);
276 fc->active_background++;
277 req->in.h.unique = fuse_get_unique(fc);
278 queue_request(fc, req);
279 }
280 }
281
282 /*
283 * This function is called when a request is finished. Either a reply
284 * has arrived or it was aborted (and not yet sent) or some error
285 * occurred during communication with userspace, or the device file
286 * was closed. The requester thread is woken up (if still waiting),
287 * the 'end' callback is called if given, else the reference to the
288 * request is released
289 *
290 * Called with fc->lock, unlocks it
291 */
292 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
293 __releases(fc->lock)
294 {
295 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
296 req->end = NULL;
297 list_del(&req->list);
298 list_del(&req->intr_entry);
299 req->state = FUSE_REQ_FINISHED;
300 if (req->background) {
301 if (fc->num_background == fc->max_background) {
302 fc->blocked = 0;
303 wake_up_all(&fc->blocked_waitq);
304 }
305 if (fc->num_background == fc->congestion_threshold &&
306 fc->connected && fc->bdi_initialized) {
307 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
308 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
309 }
310 fc->num_background--;
311 fc->active_background--;
312 flush_bg_queue(fc);
313 }
314 spin_unlock(&fc->lock);
315 wake_up(&req->waitq);
316 if (end)
317 end(fc, req);
318 fuse_put_request(fc, req);
319 }
320
321 static void wait_answer_interruptible(struct fuse_conn *fc,
322 struct fuse_req *req)
323 __releases(fc->lock)
324 __acquires(fc->lock)
325 {
326 if (signal_pending(current))
327 return;
328
329 spin_unlock(&fc->lock);
330 wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
331 spin_lock(&fc->lock);
332 }
333
334 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
335 {
336 list_add_tail(&req->intr_entry, &fc->interrupts);
337 wake_up(&fc->waitq);
338 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
339 }
340
341 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
342 __releases(fc->lock)
343 __acquires(fc->lock)
344 {
345 if (!fc->no_interrupt) {
346 /* Any signal may interrupt this */
347 wait_answer_interruptible(fc, req);
348
349 if (req->aborted)
350 goto aborted;
351 if (req->state == FUSE_REQ_FINISHED)
352 return;
353
354 req->interrupted = 1;
355 if (req->state == FUSE_REQ_SENT)
356 queue_interrupt(fc, req);
357 }
358
359 if (!req->force) {
360 sigset_t oldset;
361
362 /* Only fatal signals may interrupt this */
363 block_sigs(&oldset);
364 wait_answer_interruptible(fc, req);
365 restore_sigs(&oldset);
366
367 if (req->aborted)
368 goto aborted;
369 if (req->state == FUSE_REQ_FINISHED)
370 return;
371
372 /* Request is not yet in userspace, bail out */
373 if (req->state == FUSE_REQ_PENDING) {
374 list_del(&req->list);
375 __fuse_put_request(req);
376 req->out.h.error = -EINTR;
377 return;
378 }
379 }
380
381 /*
382 * Either request is already in userspace, or it was forced.
383 * Wait it out.
384 */
385 spin_unlock(&fc->lock);
386 wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
387 spin_lock(&fc->lock);
388
389 if (!req->aborted)
390 return;
391
392 aborted:
393 BUG_ON(req->state != FUSE_REQ_FINISHED);
394 if (req->locked) {
395 /* This is uninterruptible sleep, because data is
396 being copied to/from the buffers of req. During
397 locked state, there mustn't be any filesystem
398 operation (e.g. page fault), since that could lead
399 to deadlock */
400 spin_unlock(&fc->lock);
401 wait_event(req->waitq, !req->locked);
402 spin_lock(&fc->lock);
403 }
404 }
405
406 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
407 {
408 req->isreply = 1;
409 spin_lock(&fc->lock);
410 if (!fc->connected)
411 req->out.h.error = -ENOTCONN;
412 else if (fc->conn_error)
413 req->out.h.error = -ECONNREFUSED;
414 else {
415 req->in.h.unique = fuse_get_unique(fc);
416 queue_request(fc, req);
417 /* acquire extra reference, since request is still needed
418 after request_end() */
419 __fuse_get_request(req);
420
421 request_wait_answer(fc, req);
422 }
423 spin_unlock(&fc->lock);
424 }
425 EXPORT_SYMBOL_GPL(fuse_request_send);
426
427 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
428 struct fuse_req *req)
429 {
430 req->background = 1;
431 fc->num_background++;
432 if (fc->num_background == fc->max_background)
433 fc->blocked = 1;
434 if (fc->num_background == fc->congestion_threshold &&
435 fc->bdi_initialized) {
436 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
437 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
438 }
439 list_add_tail(&req->list, &fc->bg_queue);
440 flush_bg_queue(fc);
441 }
442
443 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
444 {
445 spin_lock(&fc->lock);
446 if (fc->connected) {
447 fuse_request_send_nowait_locked(fc, req);
448 spin_unlock(&fc->lock);
449 } else {
450 req->out.h.error = -ENOTCONN;
451 request_end(fc, req);
452 }
453 }
454
455 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
456 {
457 req->isreply = 1;
458 fuse_request_send_nowait(fc, req);
459 }
460 EXPORT_SYMBOL_GPL(fuse_request_send_background);
461
462 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
463 struct fuse_req *req, u64 unique)
464 {
465 int err = -ENODEV;
466
467 req->isreply = 0;
468 req->in.h.unique = unique;
469 spin_lock(&fc->lock);
470 if (fc->connected) {
471 queue_request(fc, req);
472 err = 0;
473 }
474 spin_unlock(&fc->lock);
475
476 return err;
477 }
478
479 /*
480 * Called under fc->lock
481 *
482 * fc->connected must have been checked previously
483 */
484 void fuse_request_send_background_locked(struct fuse_conn *fc,
485 struct fuse_req *req)
486 {
487 req->isreply = 1;
488 fuse_request_send_nowait_locked(fc, req);
489 }
490
491 /*
492 * Lock the request. Up to the next unlock_request() there mustn't be
493 * anything that could cause a page-fault. If the request was already
494 * aborted bail out.
495 */
496 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
497 {
498 int err = 0;
499 if (req) {
500 spin_lock(&fc->lock);
501 if (req->aborted)
502 err = -ENOENT;
503 else
504 req->locked = 1;
505 spin_unlock(&fc->lock);
506 }
507 return err;
508 }
509
510 /*
511 * Unlock request. If it was aborted during being locked, the
512 * requester thread is currently waiting for it to be unlocked, so
513 * wake it up.
514 */
515 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
516 {
517 if (req) {
518 spin_lock(&fc->lock);
519 req->locked = 0;
520 if (req->aborted)
521 wake_up(&req->waitq);
522 spin_unlock(&fc->lock);
523 }
524 }
525
526 struct fuse_copy_state {
527 struct fuse_conn *fc;
528 int write;
529 struct fuse_req *req;
530 const struct iovec *iov;
531 struct pipe_buffer *pipebufs;
532 struct pipe_buffer *currbuf;
533 struct pipe_inode_info *pipe;
534 unsigned long nr_segs;
535 unsigned long seglen;
536 unsigned long addr;
537 struct page *pg;
538 void *mapaddr;
539 void *buf;
540 unsigned len;
541 unsigned move_pages:1;
542 };
543
544 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
545 int write,
546 const struct iovec *iov, unsigned long nr_segs)
547 {
548 memset(cs, 0, sizeof(*cs));
549 cs->fc = fc;
550 cs->write = write;
551 cs->iov = iov;
552 cs->nr_segs = nr_segs;
553 }
554
555 /* Unmap and put previous page of userspace buffer */
556 static void fuse_copy_finish(struct fuse_copy_state *cs)
557 {
558 if (cs->currbuf) {
559 struct pipe_buffer *buf = cs->currbuf;
560
561 if (!cs->write) {
562 buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
563 } else {
564 kunmap(buf->page);
565 buf->len = PAGE_SIZE - cs->len;
566 }
567 cs->currbuf = NULL;
568 cs->mapaddr = NULL;
569 } else if (cs->mapaddr) {
570 kunmap(cs->pg);
571 if (cs->write) {
572 flush_dcache_page(cs->pg);
573 set_page_dirty_lock(cs->pg);
574 }
575 put_page(cs->pg);
576 cs->mapaddr = NULL;
577 }
578 }
579
580 /*
581 * Get another pagefull of userspace buffer, and map it to kernel
582 * address space, and lock request
583 */
584 static int fuse_copy_fill(struct fuse_copy_state *cs)
585 {
586 unsigned long offset;
587 int err;
588
589 unlock_request(cs->fc, cs->req);
590 fuse_copy_finish(cs);
591 if (cs->pipebufs) {
592 struct pipe_buffer *buf = cs->pipebufs;
593
594 if (!cs->write) {
595 err = buf->ops->confirm(cs->pipe, buf);
596 if (err)
597 return err;
598
599 BUG_ON(!cs->nr_segs);
600 cs->currbuf = buf;
601 cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
602 cs->len = buf->len;
603 cs->buf = cs->mapaddr + buf->offset;
604 cs->pipebufs++;
605 cs->nr_segs--;
606 } else {
607 struct page *page;
608
609 if (cs->nr_segs == cs->pipe->buffers)
610 return -EIO;
611
612 page = alloc_page(GFP_HIGHUSER);
613 if (!page)
614 return -ENOMEM;
615
616 buf->page = page;
617 buf->offset = 0;
618 buf->len = 0;
619
620 cs->currbuf = buf;
621 cs->mapaddr = kmap(page);
622 cs->buf = cs->mapaddr;
623 cs->len = PAGE_SIZE;
624 cs->pipebufs++;
625 cs->nr_segs++;
626 }
627 } else {
628 if (!cs->seglen) {
629 BUG_ON(!cs->nr_segs);
630 cs->seglen = cs->iov[0].iov_len;
631 cs->addr = (unsigned long) cs->iov[0].iov_base;
632 cs->iov++;
633 cs->nr_segs--;
634 }
635 err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
636 if (err < 0)
637 return err;
638 BUG_ON(err != 1);
639 offset = cs->addr % PAGE_SIZE;
640 cs->mapaddr = kmap(cs->pg);
641 cs->buf = cs->mapaddr + offset;
642 cs->len = min(PAGE_SIZE - offset, cs->seglen);
643 cs->seglen -= cs->len;
644 cs->addr += cs->len;
645 }
646
647 return lock_request(cs->fc, cs->req);
648 }
649
650 /* Do as much copy to/from userspace buffer as we can */
651 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
652 {
653 unsigned ncpy = min(*size, cs->len);
654 if (val) {
655 if (cs->write)
656 memcpy(cs->buf, *val, ncpy);
657 else
658 memcpy(*val, cs->buf, ncpy);
659 *val += ncpy;
660 }
661 *size -= ncpy;
662 cs->len -= ncpy;
663 cs->buf += ncpy;
664 return ncpy;
665 }
666
667 static int fuse_check_page(struct page *page)
668 {
669 if (page_mapcount(page) ||
670 page->mapping != NULL ||
671 page_count(page) != 1 ||
672 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
673 ~(1 << PG_locked |
674 1 << PG_referenced |
675 1 << PG_uptodate |
676 1 << PG_lru |
677 1 << PG_active |
678 1 << PG_reclaim))) {
679 printk(KERN_WARNING "fuse: trying to steal weird page\n");
680 printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
681 return 1;
682 }
683 return 0;
684 }
685
686 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
687 {
688 int err;
689 struct page *oldpage = *pagep;
690 struct page *newpage;
691 struct pipe_buffer *buf = cs->pipebufs;
692 struct address_space *mapping;
693 pgoff_t index;
694
695 unlock_request(cs->fc, cs->req);
696 fuse_copy_finish(cs);
697
698 err = buf->ops->confirm(cs->pipe, buf);
699 if (err)
700 return err;
701
702 BUG_ON(!cs->nr_segs);
703 cs->currbuf = buf;
704 cs->len = buf->len;
705 cs->pipebufs++;
706 cs->nr_segs--;
707
708 if (cs->len != PAGE_SIZE)
709 goto out_fallback;
710
711 if (buf->ops->steal(cs->pipe, buf) != 0)
712 goto out_fallback;
713
714 newpage = buf->page;
715
716 if (WARN_ON(!PageUptodate(newpage)))
717 return -EIO;
718
719 ClearPageMappedToDisk(newpage);
720
721 if (fuse_check_page(newpage) != 0)
722 goto out_fallback_unlock;
723
724 mapping = oldpage->mapping;
725 index = oldpage->index;
726
727 /*
728 * This is a new and locked page, it shouldn't be mapped or
729 * have any special flags on it
730 */
731 if (WARN_ON(page_mapped(oldpage)))
732 goto out_fallback_unlock;
733 if (WARN_ON(page_has_private(oldpage)))
734 goto out_fallback_unlock;
735 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
736 goto out_fallback_unlock;
737 if (WARN_ON(PageMlocked(oldpage)))
738 goto out_fallback_unlock;
739
740 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
741 if (err) {
742 unlock_page(newpage);
743 return err;
744 }
745
746 page_cache_get(newpage);
747
748 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
749 lru_cache_add_file(newpage);
750
751 err = 0;
752 spin_lock(&cs->fc->lock);
753 if (cs->req->aborted)
754 err = -ENOENT;
755 else
756 *pagep = newpage;
757 spin_unlock(&cs->fc->lock);
758
759 if (err) {
760 unlock_page(newpage);
761 page_cache_release(newpage);
762 return err;
763 }
764
765 unlock_page(oldpage);
766 page_cache_release(oldpage);
767 cs->len = 0;
768
769 return 0;
770
771 out_fallback_unlock:
772 unlock_page(newpage);
773 out_fallback:
774 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
775 cs->buf = cs->mapaddr + buf->offset;
776
777 err = lock_request(cs->fc, cs->req);
778 if (err)
779 return err;
780
781 return 1;
782 }
783
784 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
785 unsigned offset, unsigned count)
786 {
787 struct pipe_buffer *buf;
788
789 if (cs->nr_segs == cs->pipe->buffers)
790 return -EIO;
791
792 unlock_request(cs->fc, cs->req);
793 fuse_copy_finish(cs);
794
795 buf = cs->pipebufs;
796 page_cache_get(page);
797 buf->page = page;
798 buf->offset = offset;
799 buf->len = count;
800
801 cs->pipebufs++;
802 cs->nr_segs++;
803 cs->len = 0;
804
805 return 0;
806 }
807
808 /*
809 * Copy a page in the request to/from the userspace buffer. Must be
810 * done atomically
811 */
812 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
813 unsigned offset, unsigned count, int zeroing)
814 {
815 int err;
816 struct page *page = *pagep;
817
818 if (page && zeroing && count < PAGE_SIZE)
819 clear_highpage(page);
820
821 while (count) {
822 if (cs->write && cs->pipebufs && page) {
823 return fuse_ref_page(cs, page, offset, count);
824 } else if (!cs->len) {
825 if (cs->move_pages && page &&
826 offset == 0 && count == PAGE_SIZE) {
827 err = fuse_try_move_page(cs, pagep);
828 if (err <= 0)
829 return err;
830 } else {
831 err = fuse_copy_fill(cs);
832 if (err)
833 return err;
834 }
835 }
836 if (page) {
837 void *mapaddr = kmap_atomic(page, KM_USER0);
838 void *buf = mapaddr + offset;
839 offset += fuse_copy_do(cs, &buf, &count);
840 kunmap_atomic(mapaddr, KM_USER0);
841 } else
842 offset += fuse_copy_do(cs, NULL, &count);
843 }
844 if (page && !cs->write)
845 flush_dcache_page(page);
846 return 0;
847 }
848
849 /* Copy pages in the request to/from userspace buffer */
850 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
851 int zeroing)
852 {
853 unsigned i;
854 struct fuse_req *req = cs->req;
855 unsigned offset = req->page_offset;
856 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
857
858 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
859 int err;
860
861 err = fuse_copy_page(cs, &req->pages[i], offset, count,
862 zeroing);
863 if (err)
864 return err;
865
866 nbytes -= count;
867 count = min(nbytes, (unsigned) PAGE_SIZE);
868 offset = 0;
869 }
870 return 0;
871 }
872
873 /* Copy a single argument in the request to/from userspace buffer */
874 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
875 {
876 while (size) {
877 if (!cs->len) {
878 int err = fuse_copy_fill(cs);
879 if (err)
880 return err;
881 }
882 fuse_copy_do(cs, &val, &size);
883 }
884 return 0;
885 }
886
887 /* Copy request arguments to/from userspace buffer */
888 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
889 unsigned argpages, struct fuse_arg *args,
890 int zeroing)
891 {
892 int err = 0;
893 unsigned i;
894
895 for (i = 0; !err && i < numargs; i++) {
896 struct fuse_arg *arg = &args[i];
897 if (i == numargs - 1 && argpages)
898 err = fuse_copy_pages(cs, arg->size, zeroing);
899 else
900 err = fuse_copy_one(cs, arg->value, arg->size);
901 }
902 return err;
903 }
904
905 static int forget_pending(struct fuse_conn *fc)
906 {
907 return fc->forget_list_head.next != NULL;
908 }
909
910 static int request_pending(struct fuse_conn *fc)
911 {
912 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
913 forget_pending(fc);
914 }
915
916 /* Wait until a request is available on the pending list */
917 static void request_wait(struct fuse_conn *fc)
918 __releases(fc->lock)
919 __acquires(fc->lock)
920 {
921 DECLARE_WAITQUEUE(wait, current);
922
923 add_wait_queue_exclusive(&fc->waitq, &wait);
924 while (fc->connected && !request_pending(fc)) {
925 set_current_state(TASK_INTERRUPTIBLE);
926 if (signal_pending(current))
927 break;
928
929 spin_unlock(&fc->lock);
930 schedule();
931 spin_lock(&fc->lock);
932 }
933 set_current_state(TASK_RUNNING);
934 remove_wait_queue(&fc->waitq, &wait);
935 }
936
937 /*
938 * Transfer an interrupt request to userspace
939 *
940 * Unlike other requests this is assembled on demand, without a need
941 * to allocate a separate fuse_req structure.
942 *
943 * Called with fc->lock held, releases it
944 */
945 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
946 size_t nbytes, struct fuse_req *req)
947 __releases(fc->lock)
948 {
949 struct fuse_in_header ih;
950 struct fuse_interrupt_in arg;
951 unsigned reqsize = sizeof(ih) + sizeof(arg);
952 int err;
953
954 list_del_init(&req->intr_entry);
955 req->intr_unique = fuse_get_unique(fc);
956 memset(&ih, 0, sizeof(ih));
957 memset(&arg, 0, sizeof(arg));
958 ih.len = reqsize;
959 ih.opcode = FUSE_INTERRUPT;
960 ih.unique = req->intr_unique;
961 arg.unique = req->in.h.unique;
962
963 spin_unlock(&fc->lock);
964 if (nbytes < reqsize)
965 return -EINVAL;
966
967 err = fuse_copy_one(cs, &ih, sizeof(ih));
968 if (!err)
969 err = fuse_copy_one(cs, &arg, sizeof(arg));
970 fuse_copy_finish(cs);
971
972 return err ? err : reqsize;
973 }
974
975 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
976 unsigned max,
977 unsigned *countp)
978 {
979 struct fuse_forget_link *head = fc->forget_list_head.next;
980 struct fuse_forget_link **newhead = &head;
981 unsigned count;
982
983 for (count = 0; *newhead != NULL && count < max; count++)
984 newhead = &(*newhead)->next;
985
986 fc->forget_list_head.next = *newhead;
987 *newhead = NULL;
988 if (fc->forget_list_head.next == NULL)
989 fc->forget_list_tail = &fc->forget_list_head;
990
991 if (countp != NULL)
992 *countp = count;
993
994 return head;
995 }
996
997 static int fuse_read_single_forget(struct fuse_conn *fc,
998 struct fuse_copy_state *cs,
999 size_t nbytes)
1000 __releases(fc->lock)
1001 {
1002 int err;
1003 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1004 struct fuse_forget_in arg = {
1005 .nlookup = forget->forget_one.nlookup,
1006 };
1007 struct fuse_in_header ih = {
1008 .opcode = FUSE_FORGET,
1009 .nodeid = forget->forget_one.nodeid,
1010 .unique = fuse_get_unique(fc),
1011 .len = sizeof(ih) + sizeof(arg),
1012 };
1013
1014 spin_unlock(&fc->lock);
1015 kfree(forget);
1016 if (nbytes < ih.len)
1017 return -EINVAL;
1018
1019 err = fuse_copy_one(cs, &ih, sizeof(ih));
1020 if (!err)
1021 err = fuse_copy_one(cs, &arg, sizeof(arg));
1022 fuse_copy_finish(cs);
1023
1024 if (err)
1025 return err;
1026
1027 return ih.len;
1028 }
1029
1030 static int fuse_read_batch_forget(struct fuse_conn *fc,
1031 struct fuse_copy_state *cs, size_t nbytes)
1032 __releases(fc->lock)
1033 {
1034 int err;
1035 unsigned max_forgets;
1036 unsigned count;
1037 struct fuse_forget_link *head;
1038 struct fuse_batch_forget_in arg = { .count = 0 };
1039 struct fuse_in_header ih = {
1040 .opcode = FUSE_BATCH_FORGET,
1041 .unique = fuse_get_unique(fc),
1042 .len = sizeof(ih) + sizeof(arg),
1043 };
1044
1045 if (nbytes < ih.len) {
1046 spin_unlock(&fc->lock);
1047 return -EINVAL;
1048 }
1049
1050 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1051 head = dequeue_forget(fc, max_forgets, &count);
1052 spin_unlock(&fc->lock);
1053
1054 arg.count = count;
1055 ih.len += count * sizeof(struct fuse_forget_one);
1056 err = fuse_copy_one(cs, &ih, sizeof(ih));
1057 if (!err)
1058 err = fuse_copy_one(cs, &arg, sizeof(arg));
1059
1060 while (head) {
1061 struct fuse_forget_link *forget = head;
1062
1063 if (!err) {
1064 err = fuse_copy_one(cs, &forget->forget_one,
1065 sizeof(forget->forget_one));
1066 }
1067 head = forget->next;
1068 kfree(forget);
1069 }
1070
1071 fuse_copy_finish(cs);
1072
1073 if (err)
1074 return err;
1075
1076 return ih.len;
1077 }
1078
1079 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1080 size_t nbytes)
1081 __releases(fc->lock)
1082 {
1083 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1084 return fuse_read_single_forget(fc, cs, nbytes);
1085 else
1086 return fuse_read_batch_forget(fc, cs, nbytes);
1087 }
1088
1089 /*
1090 * Read a single request into the userspace filesystem's buffer. This
1091 * function waits until a request is available, then removes it from
1092 * the pending list and copies request data to userspace buffer. If
1093 * no reply is needed (FORGET) or request has been aborted or there
1094 * was an error during the copying then it's finished by calling
1095 * request_end(). Otherwise add it to the processing list, and set
1096 * the 'sent' flag.
1097 */
1098 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1099 struct fuse_copy_state *cs, size_t nbytes)
1100 {
1101 int err;
1102 struct fuse_req *req;
1103 struct fuse_in *in;
1104 unsigned reqsize;
1105
1106 restart:
1107 spin_lock(&fc->lock);
1108 err = -EAGAIN;
1109 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1110 !request_pending(fc))
1111 goto err_unlock;
1112
1113 request_wait(fc);
1114 err = -ENODEV;
1115 if (!fc->connected)
1116 goto err_unlock;
1117 err = -ERESTARTSYS;
1118 if (!request_pending(fc))
1119 goto err_unlock;
1120
1121 if (!list_empty(&fc->interrupts)) {
1122 req = list_entry(fc->interrupts.next, struct fuse_req,
1123 intr_entry);
1124 return fuse_read_interrupt(fc, cs, nbytes, req);
1125 }
1126
1127 if (forget_pending(fc)) {
1128 if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1129 return fuse_read_forget(fc, cs, nbytes);
1130
1131 if (fc->forget_batch <= -8)
1132 fc->forget_batch = 16;
1133 }
1134
1135 req = list_entry(fc->pending.next, struct fuse_req, list);
1136 req->state = FUSE_REQ_READING;
1137 list_move(&req->list, &fc->io);
1138
1139 in = &req->in;
1140 reqsize = in->h.len;
1141 /* If request is too large, reply with an error and restart the read */
1142 if (nbytes < reqsize) {
1143 req->out.h.error = -EIO;
1144 /* SETXATTR is special, since it may contain too large data */
1145 if (in->h.opcode == FUSE_SETXATTR)
1146 req->out.h.error = -E2BIG;
1147 request_end(fc, req);
1148 goto restart;
1149 }
1150 spin_unlock(&fc->lock);
1151 cs->req = req;
1152 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1153 if (!err)
1154 err = fuse_copy_args(cs, in->numargs, in->argpages,
1155 (struct fuse_arg *) in->args, 0);
1156 fuse_copy_finish(cs);
1157 spin_lock(&fc->lock);
1158 req->locked = 0;
1159 if (req->aborted) {
1160 request_end(fc, req);
1161 return -ENODEV;
1162 }
1163 if (err) {
1164 req->out.h.error = -EIO;
1165 request_end(fc, req);
1166 return err;
1167 }
1168 if (!req->isreply)
1169 request_end(fc, req);
1170 else {
1171 req->state = FUSE_REQ_SENT;
1172 list_move_tail(&req->list, &fc->processing);
1173 if (req->interrupted)
1174 queue_interrupt(fc, req);
1175 spin_unlock(&fc->lock);
1176 }
1177 return reqsize;
1178
1179 err_unlock:
1180 spin_unlock(&fc->lock);
1181 return err;
1182 }
1183
1184 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1185 unsigned long nr_segs, loff_t pos)
1186 {
1187 struct fuse_copy_state cs;
1188 struct file *file = iocb->ki_filp;
1189 struct fuse_conn *fc = fuse_get_conn(file);
1190 if (!fc)
1191 return -EPERM;
1192
1193 fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1194
1195 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1196 }
1197
1198 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1199 struct pipe_buffer *buf)
1200 {
1201 return 1;
1202 }
1203
1204 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1205 .can_merge = 0,
1206 .map = generic_pipe_buf_map,
1207 .unmap = generic_pipe_buf_unmap,
1208 .confirm = generic_pipe_buf_confirm,
1209 .release = generic_pipe_buf_release,
1210 .steal = fuse_dev_pipe_buf_steal,
1211 .get = generic_pipe_buf_get,
1212 };
1213
1214 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1215 struct pipe_inode_info *pipe,
1216 size_t len, unsigned int flags)
1217 {
1218 int ret;
1219 int page_nr = 0;
1220 int do_wakeup = 0;
1221 struct pipe_buffer *bufs;
1222 struct fuse_copy_state cs;
1223 struct fuse_conn *fc = fuse_get_conn(in);
1224 if (!fc)
1225 return -EPERM;
1226
1227 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1228 if (!bufs)
1229 return -ENOMEM;
1230
1231 fuse_copy_init(&cs, fc, 1, NULL, 0);
1232 cs.pipebufs = bufs;
1233 cs.pipe = pipe;
1234 ret = fuse_dev_do_read(fc, in, &cs, len);
1235 if (ret < 0)
1236 goto out;
1237
1238 ret = 0;
1239 pipe_lock(pipe);
1240
1241 if (!pipe->readers) {
1242 send_sig(SIGPIPE, current, 0);
1243 if (!ret)
1244 ret = -EPIPE;
1245 goto out_unlock;
1246 }
1247
1248 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1249 ret = -EIO;
1250 goto out_unlock;
1251 }
1252
1253 while (page_nr < cs.nr_segs) {
1254 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1255 struct pipe_buffer *buf = pipe->bufs + newbuf;
1256
1257 buf->page = bufs[page_nr].page;
1258 buf->offset = bufs[page_nr].offset;
1259 buf->len = bufs[page_nr].len;
1260 buf->ops = &fuse_dev_pipe_buf_ops;
1261
1262 pipe->nrbufs++;
1263 page_nr++;
1264 ret += buf->len;
1265
1266 if (pipe->inode)
1267 do_wakeup = 1;
1268 }
1269
1270 out_unlock:
1271 pipe_unlock(pipe);
1272
1273 if (do_wakeup) {
1274 smp_mb();
1275 if (waitqueue_active(&pipe->wait))
1276 wake_up_interruptible(&pipe->wait);
1277 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1278 }
1279
1280 out:
1281 for (; page_nr < cs.nr_segs; page_nr++)
1282 page_cache_release(bufs[page_nr].page);
1283
1284 kfree(bufs);
1285 return ret;
1286 }
1287
1288 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1289 struct fuse_copy_state *cs)
1290 {
1291 struct fuse_notify_poll_wakeup_out outarg;
1292 int err = -EINVAL;
1293
1294 if (size != sizeof(outarg))
1295 goto err;
1296
1297 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1298 if (err)
1299 goto err;
1300
1301 fuse_copy_finish(cs);
1302 return fuse_notify_poll_wakeup(fc, &outarg);
1303
1304 err:
1305 fuse_copy_finish(cs);
1306 return err;
1307 }
1308
1309 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1310 struct fuse_copy_state *cs)
1311 {
1312 struct fuse_notify_inval_inode_out outarg;
1313 int err = -EINVAL;
1314
1315 if (size != sizeof(outarg))
1316 goto err;
1317
1318 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1319 if (err)
1320 goto err;
1321 fuse_copy_finish(cs);
1322
1323 down_read(&fc->killsb);
1324 err = -ENOENT;
1325 if (fc->sb) {
1326 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1327 outarg.off, outarg.len);
1328 }
1329 up_read(&fc->killsb);
1330 return err;
1331
1332 err:
1333 fuse_copy_finish(cs);
1334 return err;
1335 }
1336
1337 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1338 struct fuse_copy_state *cs)
1339 {
1340 struct fuse_notify_inval_entry_out outarg;
1341 int err = -ENOMEM;
1342 char *buf;
1343 struct qstr name;
1344
1345 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1346 if (!buf)
1347 goto err;
1348
1349 err = -EINVAL;
1350 if (size < sizeof(outarg))
1351 goto err;
1352
1353 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1354 if (err)
1355 goto err;
1356
1357 err = -ENAMETOOLONG;
1358 if (outarg.namelen > FUSE_NAME_MAX)
1359 goto err;
1360
1361 name.name = buf;
1362 name.len = outarg.namelen;
1363 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1364 if (err)
1365 goto err;
1366 fuse_copy_finish(cs);
1367 buf[outarg.namelen] = 0;
1368 name.hash = full_name_hash(name.name, name.len);
1369
1370 down_read(&fc->killsb);
1371 err = -ENOENT;
1372 if (fc->sb)
1373 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name);
1374 up_read(&fc->killsb);
1375 kfree(buf);
1376 return err;
1377
1378 err:
1379 kfree(buf);
1380 fuse_copy_finish(cs);
1381 return err;
1382 }
1383
1384 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1385 struct fuse_copy_state *cs)
1386 {
1387 struct fuse_notify_store_out outarg;
1388 struct inode *inode;
1389 struct address_space *mapping;
1390 u64 nodeid;
1391 int err;
1392 pgoff_t index;
1393 unsigned int offset;
1394 unsigned int num;
1395 loff_t file_size;
1396 loff_t end;
1397
1398 err = -EINVAL;
1399 if (size < sizeof(outarg))
1400 goto out_finish;
1401
1402 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1403 if (err)
1404 goto out_finish;
1405
1406 err = -EINVAL;
1407 if (size - sizeof(outarg) != outarg.size)
1408 goto out_finish;
1409
1410 nodeid = outarg.nodeid;
1411
1412 down_read(&fc->killsb);
1413
1414 err = -ENOENT;
1415 if (!fc->sb)
1416 goto out_up_killsb;
1417
1418 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1419 if (!inode)
1420 goto out_up_killsb;
1421
1422 mapping = inode->i_mapping;
1423 index = outarg.offset >> PAGE_CACHE_SHIFT;
1424 offset = outarg.offset & ~PAGE_CACHE_MASK;
1425 file_size = i_size_read(inode);
1426 end = outarg.offset + outarg.size;
1427 if (end > file_size) {
1428 file_size = end;
1429 fuse_write_update_size(inode, file_size);
1430 }
1431
1432 num = outarg.size;
1433 while (num) {
1434 struct page *page;
1435 unsigned int this_num;
1436
1437 err = -ENOMEM;
1438 page = find_or_create_page(mapping, index,
1439 mapping_gfp_mask(mapping));
1440 if (!page)
1441 goto out_iput;
1442
1443 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1444 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1445 if (!err && offset == 0 && (num != 0 || file_size == end))
1446 SetPageUptodate(page);
1447 unlock_page(page);
1448 page_cache_release(page);
1449
1450 if (err)
1451 goto out_iput;
1452
1453 num -= this_num;
1454 offset = 0;
1455 index++;
1456 }
1457
1458 err = 0;
1459
1460 out_iput:
1461 iput(inode);
1462 out_up_killsb:
1463 up_read(&fc->killsb);
1464 out_finish:
1465 fuse_copy_finish(cs);
1466 return err;
1467 }
1468
1469 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1470 {
1471 release_pages(req->pages, req->num_pages, 0);
1472 }
1473
1474 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1475 struct fuse_notify_retrieve_out *outarg)
1476 {
1477 int err;
1478 struct address_space *mapping = inode->i_mapping;
1479 struct fuse_req *req;
1480 pgoff_t index;
1481 loff_t file_size;
1482 unsigned int num;
1483 unsigned int offset;
1484 size_t total_len = 0;
1485
1486 req = fuse_get_req(fc);
1487 if (IS_ERR(req))
1488 return PTR_ERR(req);
1489
1490 offset = outarg->offset & ~PAGE_CACHE_MASK;
1491
1492 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1493 req->in.h.nodeid = outarg->nodeid;
1494 req->in.numargs = 2;
1495 req->in.argpages = 1;
1496 req->page_offset = offset;
1497 req->end = fuse_retrieve_end;
1498
1499 index = outarg->offset >> PAGE_CACHE_SHIFT;
1500 file_size = i_size_read(inode);
1501 num = outarg->size;
1502 if (outarg->offset > file_size)
1503 num = 0;
1504 else if (outarg->offset + num > file_size)
1505 num = file_size - outarg->offset;
1506
1507 while (num) {
1508 struct page *page;
1509 unsigned int this_num;
1510
1511 page = find_get_page(mapping, index);
1512 if (!page)
1513 break;
1514
1515 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1516 req->pages[req->num_pages] = page;
1517 req->num_pages++;
1518
1519 num -= this_num;
1520 total_len += this_num;
1521 }
1522 req->misc.retrieve_in.offset = outarg->offset;
1523 req->misc.retrieve_in.size = total_len;
1524 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1525 req->in.args[0].value = &req->misc.retrieve_in;
1526 req->in.args[1].size = total_len;
1527
1528 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1529 if (err)
1530 fuse_retrieve_end(fc, req);
1531
1532 return err;
1533 }
1534
1535 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1536 struct fuse_copy_state *cs)
1537 {
1538 struct fuse_notify_retrieve_out outarg;
1539 struct inode *inode;
1540 int err;
1541
1542 err = -EINVAL;
1543 if (size != sizeof(outarg))
1544 goto copy_finish;
1545
1546 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1547 if (err)
1548 goto copy_finish;
1549
1550 fuse_copy_finish(cs);
1551
1552 down_read(&fc->killsb);
1553 err = -ENOENT;
1554 if (fc->sb) {
1555 u64 nodeid = outarg.nodeid;
1556
1557 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1558 if (inode) {
1559 err = fuse_retrieve(fc, inode, &outarg);
1560 iput(inode);
1561 }
1562 }
1563 up_read(&fc->killsb);
1564
1565 return err;
1566
1567 copy_finish:
1568 fuse_copy_finish(cs);
1569 return err;
1570 }
1571
1572 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1573 unsigned int size, struct fuse_copy_state *cs)
1574 {
1575 switch (code) {
1576 case FUSE_NOTIFY_POLL:
1577 return fuse_notify_poll(fc, size, cs);
1578
1579 case FUSE_NOTIFY_INVAL_INODE:
1580 return fuse_notify_inval_inode(fc, size, cs);
1581
1582 case FUSE_NOTIFY_INVAL_ENTRY:
1583 return fuse_notify_inval_entry(fc, size, cs);
1584
1585 case FUSE_NOTIFY_STORE:
1586 return fuse_notify_store(fc, size, cs);
1587
1588 case FUSE_NOTIFY_RETRIEVE:
1589 return fuse_notify_retrieve(fc, size, cs);
1590
1591 default:
1592 fuse_copy_finish(cs);
1593 return -EINVAL;
1594 }
1595 }
1596
1597 /* Look up request on processing list by unique ID */
1598 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1599 {
1600 struct list_head *entry;
1601
1602 list_for_each(entry, &fc->processing) {
1603 struct fuse_req *req;
1604 req = list_entry(entry, struct fuse_req, list);
1605 if (req->in.h.unique == unique || req->intr_unique == unique)
1606 return req;
1607 }
1608 return NULL;
1609 }
1610
1611 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1612 unsigned nbytes)
1613 {
1614 unsigned reqsize = sizeof(struct fuse_out_header);
1615
1616 if (out->h.error)
1617 return nbytes != reqsize ? -EINVAL : 0;
1618
1619 reqsize += len_args(out->numargs, out->args);
1620
1621 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1622 return -EINVAL;
1623 else if (reqsize > nbytes) {
1624 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1625 unsigned diffsize = reqsize - nbytes;
1626 if (diffsize > lastarg->size)
1627 return -EINVAL;
1628 lastarg->size -= diffsize;
1629 }
1630 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1631 out->page_zeroing);
1632 }
1633
1634 /*
1635 * Write a single reply to a request. First the header is copied from
1636 * the write buffer. The request is then searched on the processing
1637 * list by the unique ID found in the header. If found, then remove
1638 * it from the list and copy the rest of the buffer to the request.
1639 * The request is finished by calling request_end()
1640 */
1641 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1642 struct fuse_copy_state *cs, size_t nbytes)
1643 {
1644 int err;
1645 struct fuse_req *req;
1646 struct fuse_out_header oh;
1647
1648 if (nbytes < sizeof(struct fuse_out_header))
1649 return -EINVAL;
1650
1651 err = fuse_copy_one(cs, &oh, sizeof(oh));
1652 if (err)
1653 goto err_finish;
1654
1655 err = -EINVAL;
1656 if (oh.len != nbytes)
1657 goto err_finish;
1658
1659 /*
1660 * Zero oh.unique indicates unsolicited notification message
1661 * and error contains notification code.
1662 */
1663 if (!oh.unique) {
1664 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1665 return err ? err : nbytes;
1666 }
1667
1668 err = -EINVAL;
1669 if (oh.error <= -1000 || oh.error > 0)
1670 goto err_finish;
1671
1672 spin_lock(&fc->lock);
1673 err = -ENOENT;
1674 if (!fc->connected)
1675 goto err_unlock;
1676
1677 req = request_find(fc, oh.unique);
1678 if (!req)
1679 goto err_unlock;
1680
1681 if (req->aborted) {
1682 spin_unlock(&fc->lock);
1683 fuse_copy_finish(cs);
1684 spin_lock(&fc->lock);
1685 request_end(fc, req);
1686 return -ENOENT;
1687 }
1688 /* Is it an interrupt reply? */
1689 if (req->intr_unique == oh.unique) {
1690 err = -EINVAL;
1691 if (nbytes != sizeof(struct fuse_out_header))
1692 goto err_unlock;
1693
1694 if (oh.error == -ENOSYS)
1695 fc->no_interrupt = 1;
1696 else if (oh.error == -EAGAIN)
1697 queue_interrupt(fc, req);
1698
1699 spin_unlock(&fc->lock);
1700 fuse_copy_finish(cs);
1701 return nbytes;
1702 }
1703
1704 req->state = FUSE_REQ_WRITING;
1705 list_move(&req->list, &fc->io);
1706 req->out.h = oh;
1707 req->locked = 1;
1708 cs->req = req;
1709 if (!req->out.page_replace)
1710 cs->move_pages = 0;
1711 spin_unlock(&fc->lock);
1712
1713 err = copy_out_args(cs, &req->out, nbytes);
1714 fuse_copy_finish(cs);
1715
1716 spin_lock(&fc->lock);
1717 req->locked = 0;
1718 if (!err) {
1719 if (req->aborted)
1720 err = -ENOENT;
1721 } else if (!req->aborted)
1722 req->out.h.error = -EIO;
1723 request_end(fc, req);
1724
1725 return err ? err : nbytes;
1726
1727 err_unlock:
1728 spin_unlock(&fc->lock);
1729 err_finish:
1730 fuse_copy_finish(cs);
1731 return err;
1732 }
1733
1734 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1735 unsigned long nr_segs, loff_t pos)
1736 {
1737 struct fuse_copy_state cs;
1738 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1739 if (!fc)
1740 return -EPERM;
1741
1742 fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1743
1744 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1745 }
1746
1747 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1748 struct file *out, loff_t *ppos,
1749 size_t len, unsigned int flags)
1750 {
1751 unsigned nbuf;
1752 unsigned idx;
1753 struct pipe_buffer *bufs;
1754 struct fuse_copy_state cs;
1755 struct fuse_conn *fc;
1756 size_t rem;
1757 ssize_t ret;
1758
1759 fc = fuse_get_conn(out);
1760 if (!fc)
1761 return -EPERM;
1762
1763 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1764 if (!bufs)
1765 return -ENOMEM;
1766
1767 pipe_lock(pipe);
1768 nbuf = 0;
1769 rem = 0;
1770 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1771 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1772
1773 ret = -EINVAL;
1774 if (rem < len) {
1775 pipe_unlock(pipe);
1776 goto out;
1777 }
1778
1779 rem = len;
1780 while (rem) {
1781 struct pipe_buffer *ibuf;
1782 struct pipe_buffer *obuf;
1783
1784 BUG_ON(nbuf >= pipe->buffers);
1785 BUG_ON(!pipe->nrbufs);
1786 ibuf = &pipe->bufs[pipe->curbuf];
1787 obuf = &bufs[nbuf];
1788
1789 if (rem >= ibuf->len) {
1790 *obuf = *ibuf;
1791 ibuf->ops = NULL;
1792 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1793 pipe->nrbufs--;
1794 } else {
1795 ibuf->ops->get(pipe, ibuf);
1796 *obuf = *ibuf;
1797 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1798 obuf->len = rem;
1799 ibuf->offset += obuf->len;
1800 ibuf->len -= obuf->len;
1801 }
1802 nbuf++;
1803 rem -= obuf->len;
1804 }
1805 pipe_unlock(pipe);
1806
1807 fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1808 cs.pipebufs = bufs;
1809 cs.pipe = pipe;
1810
1811 if (flags & SPLICE_F_MOVE)
1812 cs.move_pages = 1;
1813
1814 ret = fuse_dev_do_write(fc, &cs, len);
1815
1816 for (idx = 0; idx < nbuf; idx++) {
1817 struct pipe_buffer *buf = &bufs[idx];
1818 buf->ops->release(pipe, buf);
1819 }
1820 out:
1821 kfree(bufs);
1822 return ret;
1823 }
1824
1825 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1826 {
1827 unsigned mask = POLLOUT | POLLWRNORM;
1828 struct fuse_conn *fc = fuse_get_conn(file);
1829 if (!fc)
1830 return POLLERR;
1831
1832 poll_wait(file, &fc->waitq, wait);
1833
1834 spin_lock(&fc->lock);
1835 if (!fc->connected)
1836 mask = POLLERR;
1837 else if (request_pending(fc))
1838 mask |= POLLIN | POLLRDNORM;
1839 spin_unlock(&fc->lock);
1840
1841 return mask;
1842 }
1843
1844 /*
1845 * Abort all requests on the given list (pending or processing)
1846 *
1847 * This function releases and reacquires fc->lock
1848 */
1849 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1850 __releases(fc->lock)
1851 __acquires(fc->lock)
1852 {
1853 while (!list_empty(head)) {
1854 struct fuse_req *req;
1855 req = list_entry(head->next, struct fuse_req, list);
1856 req->out.h.error = -ECONNABORTED;
1857 request_end(fc, req);
1858 spin_lock(&fc->lock);
1859 }
1860 }
1861
1862 /*
1863 * Abort requests under I/O
1864 *
1865 * The requests are set to aborted and finished, and the request
1866 * waiter is woken up. This will make request_wait_answer() wait
1867 * until the request is unlocked and then return.
1868 *
1869 * If the request is asynchronous, then the end function needs to be
1870 * called after waiting for the request to be unlocked (if it was
1871 * locked).
1872 */
1873 static void end_io_requests(struct fuse_conn *fc)
1874 __releases(fc->lock)
1875 __acquires(fc->lock)
1876 {
1877 while (!list_empty(&fc->io)) {
1878 struct fuse_req *req =
1879 list_entry(fc->io.next, struct fuse_req, list);
1880 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1881
1882 req->aborted = 1;
1883 req->out.h.error = -ECONNABORTED;
1884 req->state = FUSE_REQ_FINISHED;
1885 list_del_init(&req->list);
1886 wake_up(&req->waitq);
1887 if (end) {
1888 req->end = NULL;
1889 __fuse_get_request(req);
1890 spin_unlock(&fc->lock);
1891 wait_event(req->waitq, !req->locked);
1892 end(fc, req);
1893 fuse_put_request(fc, req);
1894 spin_lock(&fc->lock);
1895 }
1896 }
1897 }
1898
1899 static void end_queued_requests(struct fuse_conn *fc)
1900 __releases(fc->lock)
1901 __acquires(fc->lock)
1902 {
1903 fc->max_background = UINT_MAX;
1904 flush_bg_queue(fc);
1905 end_requests(fc, &fc->pending);
1906 end_requests(fc, &fc->processing);
1907 while (forget_pending(fc))
1908 kfree(dequeue_forget(fc, 1, NULL));
1909 }
1910
1911 static void end_polls(struct fuse_conn *fc)
1912 {
1913 struct rb_node *p;
1914
1915 p = rb_first(&fc->polled_files);
1916
1917 while (p) {
1918 struct fuse_file *ff;
1919 ff = rb_entry(p, struct fuse_file, polled_node);
1920 wake_up_interruptible_all(&ff->poll_wait);
1921
1922 p = rb_next(p);
1923 }
1924 }
1925
1926 /*
1927 * Abort all requests.
1928 *
1929 * Emergency exit in case of a malicious or accidental deadlock, or
1930 * just a hung filesystem.
1931 *
1932 * The same effect is usually achievable through killing the
1933 * filesystem daemon and all users of the filesystem. The exception
1934 * is the combination of an asynchronous request and the tricky
1935 * deadlock (see Documentation/filesystems/fuse.txt).
1936 *
1937 * During the aborting, progression of requests from the pending and
1938 * processing lists onto the io list, and progression of new requests
1939 * onto the pending list is prevented by req->connected being false.
1940 *
1941 * Progression of requests under I/O to the processing list is
1942 * prevented by the req->aborted flag being true for these requests.
1943 * For this reason requests on the io list must be aborted first.
1944 */
1945 void fuse_abort_conn(struct fuse_conn *fc)
1946 {
1947 spin_lock(&fc->lock);
1948 if (fc->connected) {
1949 fc->connected = 0;
1950 fc->blocked = 0;
1951 end_io_requests(fc);
1952 end_queued_requests(fc);
1953 end_polls(fc);
1954 wake_up_all(&fc->waitq);
1955 wake_up_all(&fc->blocked_waitq);
1956 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1957 }
1958 spin_unlock(&fc->lock);
1959 }
1960 EXPORT_SYMBOL_GPL(fuse_abort_conn);
1961
1962 int fuse_dev_release(struct inode *inode, struct file *file)
1963 {
1964 struct fuse_conn *fc = fuse_get_conn(file);
1965 if (fc) {
1966 spin_lock(&fc->lock);
1967 fc->connected = 0;
1968 fc->blocked = 0;
1969 end_queued_requests(fc);
1970 end_polls(fc);
1971 wake_up_all(&fc->blocked_waitq);
1972 spin_unlock(&fc->lock);
1973 fuse_conn_put(fc);
1974 }
1975
1976 return 0;
1977 }
1978 EXPORT_SYMBOL_GPL(fuse_dev_release);
1979
1980 static int fuse_dev_fasync(int fd, struct file *file, int on)
1981 {
1982 struct fuse_conn *fc = fuse_get_conn(file);
1983 if (!fc)
1984 return -EPERM;
1985
1986 /* No locking - fasync_helper does its own locking */
1987 return fasync_helper(fd, file, on, &fc->fasync);
1988 }
1989
1990 const struct file_operations fuse_dev_operations = {
1991 .owner = THIS_MODULE,
1992 .llseek = no_llseek,
1993 .read = do_sync_read,
1994 .aio_read = fuse_dev_read,
1995 .splice_read = fuse_dev_splice_read,
1996 .write = do_sync_write,
1997 .aio_write = fuse_dev_write,
1998 .splice_write = fuse_dev_splice_write,
1999 .poll = fuse_dev_poll,
2000 .release = fuse_dev_release,
2001 .fasync = fuse_dev_fasync,
2002 };
2003 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2004
2005 static struct miscdevice fuse_miscdevice = {
2006 .minor = FUSE_MINOR,
2007 .name = "fuse",
2008 .fops = &fuse_dev_operations,
2009 };
2010
2011 int __init fuse_dev_init(void)
2012 {
2013 int err = -ENOMEM;
2014 fuse_req_cachep = kmem_cache_create("fuse_request",
2015 sizeof(struct fuse_req),
2016 0, 0, NULL);
2017 if (!fuse_req_cachep)
2018 goto out;
2019
2020 err = misc_register(&fuse_miscdevice);
2021 if (err)
2022 goto out_cache_clean;
2023
2024 return 0;
2025
2026 out_cache_clean:
2027 kmem_cache_destroy(fuse_req_cachep);
2028 out:
2029 return err;
2030 }
2031
2032 void fuse_dev_cleanup(void)
2033 {
2034 misc_deregister(&fuse_miscdevice);
2035 kmem_cache_destroy(fuse_req_cachep);
2036 }
Linux 2.6 libata-dev (mirror)