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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 #include <linux/freezer.h>
23 
24 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
25 MODULE_ALIAS("devname:fuse");
26 
27 static struct kmem_cache *fuse_req_cachep;
28 
fuse_get_conn(struct file * file)29 static struct fuse_conn *fuse_get_conn(struct file *file)
30 {
31 	/*
32 	 * Lockless access is OK, because file->private data is set
33 	 * once during mount and is valid until the file is released.
34 	 */
35 	return file->private_data;
36 }
37 
fuse_request_init(struct fuse_req * req)38 static void fuse_request_init(struct fuse_req *req)
39 {
40 	memset(req, 0, sizeof(*req));
41 	INIT_LIST_HEAD(&req->list);
42 	INIT_LIST_HEAD(&req->intr_entry);
43 	init_waitqueue_head(&req->waitq);
44 	atomic_set(&req->count, 1);
45 }
46 
fuse_request_alloc(void)47 struct fuse_req *fuse_request_alloc(void)
48 {
49 	struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
50 	if (req)
51 		fuse_request_init(req);
52 	return req;
53 }
54 EXPORT_SYMBOL_GPL(fuse_request_alloc);
55 
fuse_request_alloc_nofs(void)56 struct fuse_req *fuse_request_alloc_nofs(void)
57 {
58 	struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
59 	if (req)
60 		fuse_request_init(req);
61 	return req;
62 }
63 
fuse_request_free(struct fuse_req * req)64 void fuse_request_free(struct fuse_req *req)
65 {
66 	kmem_cache_free(fuse_req_cachep, req);
67 }
68 
block_sigs(sigset_t * oldset)69 static void block_sigs(sigset_t *oldset)
70 {
71 	sigset_t mask;
72 
73 	siginitsetinv(&mask, sigmask(SIGKILL));
74 	sigprocmask(SIG_BLOCK, &mask, oldset);
75 }
76 
restore_sigs(sigset_t * oldset)77 static void restore_sigs(sigset_t *oldset)
78 {
79 	sigprocmask(SIG_SETMASK, oldset, NULL);
80 }
81 
__fuse_get_request(struct fuse_req * req)82 static void __fuse_get_request(struct fuse_req *req)
83 {
84 	atomic_inc(&req->count);
85 }
86 
87 /* Must be called with > 1 refcount */
__fuse_put_request(struct fuse_req * req)88 static void __fuse_put_request(struct fuse_req *req)
89 {
90 	BUG_ON(atomic_read(&req->count) < 2);
91 	atomic_dec(&req->count);
92 }
93 
fuse_req_init_context(struct fuse_req * req)94 static void fuse_req_init_context(struct fuse_req *req)
95 {
96 	req->in.h.uid = current_fsuid();
97 	req->in.h.gid = current_fsgid();
98 	req->in.h.pid = current->pid;
99 }
100 
fuse_get_req(struct fuse_conn * fc)101 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
102 {
103 	struct fuse_req *req;
104 	sigset_t oldset;
105 	int intr;
106 	int err;
107 
108 	atomic_inc(&fc->num_waiting);
109 	block_sigs(&oldset);
110 	intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
111 	restore_sigs(&oldset);
112 	err = -EINTR;
113 	if (intr)
114 		goto out;
115 
116 	err = -ENOTCONN;
117 	if (!fc->connected)
118 		goto out;
119 
120 	req = fuse_request_alloc();
121 	err = -ENOMEM;
122 	if (!req)
123 		goto out;
124 
125 	fuse_req_init_context(req);
126 	req->waiting = 1;
127 	return req;
128 
129  out:
130 	atomic_dec(&fc->num_waiting);
131 	return ERR_PTR(err);
132 }
133 EXPORT_SYMBOL_GPL(fuse_get_req);
134 
135 /*
136  * Return request in fuse_file->reserved_req.  However that may
137  * currently be in use.  If that is the case, wait for it to become
138  * available.
139  */
get_reserved_req(struct fuse_conn * fc,struct file * file)140 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
141 					 struct file *file)
142 {
143 	struct fuse_req *req = NULL;
144 	struct fuse_file *ff = file->private_data;
145 
146 	do {
147 		wait_event(fc->reserved_req_waitq, ff->reserved_req);
148 		spin_lock(&fc->lock);
149 		if (ff->reserved_req) {
150 			req = ff->reserved_req;
151 			ff->reserved_req = NULL;
152 			get_file(file);
153 			req->stolen_file = file;
154 		}
155 		spin_unlock(&fc->lock);
156 	} while (!req);
157 
158 	return req;
159 }
160 
161 /*
162  * Put stolen request back into fuse_file->reserved_req
163  */
put_reserved_req(struct fuse_conn * fc,struct fuse_req * req)164 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
165 {
166 	struct file *file = req->stolen_file;
167 	struct fuse_file *ff = file->private_data;
168 
169 	spin_lock(&fc->lock);
170 	fuse_request_init(req);
171 	BUG_ON(ff->reserved_req);
172 	ff->reserved_req = req;
173 	wake_up_all(&fc->reserved_req_waitq);
174 	spin_unlock(&fc->lock);
175 	fput(file);
176 }
177 
178 /*
179  * Gets a requests for a file operation, always succeeds
180  *
181  * This is used for sending the FLUSH request, which must get to
182  * userspace, due to POSIX locks which may need to be unlocked.
183  *
184  * If allocation fails due to OOM, use the reserved request in
185  * fuse_file.
186  *
187  * This is very unlikely to deadlock accidentally, since the
188  * filesystem should not have it's own file open.  If deadlock is
189  * intentional, it can still be broken by "aborting" the filesystem.
190  */
fuse_get_req_nofail(struct fuse_conn * fc,struct file * file)191 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
192 {
193 	struct fuse_req *req;
194 
195 	atomic_inc(&fc->num_waiting);
196 	wait_event(fc->blocked_waitq, !fc->blocked);
197 	req = fuse_request_alloc();
198 	if (!req)
199 		req = get_reserved_req(fc, file);
200 
201 	fuse_req_init_context(req);
202 	req->waiting = 1;
203 	return req;
204 }
205 
fuse_put_request(struct fuse_conn * fc,struct fuse_req * req)206 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
207 {
208 	if (atomic_dec_and_test(&req->count)) {
209 		if (req->waiting)
210 			atomic_dec(&fc->num_waiting);
211 
212 		if (req->stolen_file)
213 			put_reserved_req(fc, req);
214 		else
215 			fuse_request_free(req);
216 	}
217 }
218 EXPORT_SYMBOL_GPL(fuse_put_request);
219 
len_args(unsigned numargs,struct fuse_arg * args)220 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
221 {
222 	unsigned nbytes = 0;
223 	unsigned i;
224 
225 	for (i = 0; i < numargs; i++)
226 		nbytes += args[i].size;
227 
228 	return nbytes;
229 }
230 
fuse_get_unique(struct fuse_conn * fc)231 static u64 fuse_get_unique(struct fuse_conn *fc)
232 {
233 	fc->reqctr++;
234 	/* zero is special */
235 	if (fc->reqctr == 0)
236 		fc->reqctr = 1;
237 
238 	return fc->reqctr;
239 }
240 
queue_request(struct fuse_conn * fc,struct fuse_req * req)241 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
242 {
243 	req->in.h.len = sizeof(struct fuse_in_header) +
244 		len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
245 	list_add_tail(&req->list, &fc->pending);
246 	req->state = FUSE_REQ_PENDING;
247 	if (!req->waiting) {
248 		req->waiting = 1;
249 		atomic_inc(&fc->num_waiting);
250 	}
251 	wake_up(&fc->waitq);
252 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
253 }
254 
fuse_queue_forget(struct fuse_conn * fc,struct fuse_forget_link * forget,u64 nodeid,u64 nlookup)255 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
256 		       u64 nodeid, u64 nlookup)
257 {
258 	forget->forget_one.nodeid = nodeid;
259 	forget->forget_one.nlookup = nlookup;
260 
261 	spin_lock(&fc->lock);
262 	if (fc->connected) {
263 		fc->forget_list_tail->next = forget;
264 		fc->forget_list_tail = forget;
265 		wake_up(&fc->waitq);
266 		kill_fasync(&fc->fasync, SIGIO, POLL_IN);
267 	} else {
268 		kfree(forget);
269 	}
270 	spin_unlock(&fc->lock);
271 }
272 
flush_bg_queue(struct fuse_conn * fc)273 static void flush_bg_queue(struct fuse_conn *fc)
274 {
275 	while (fc->active_background < fc->max_background &&
276 	       !list_empty(&fc->bg_queue)) {
277 		struct fuse_req *req;
278 
279 		req = list_entry(fc->bg_queue.next, struct fuse_req, list);
280 		list_del(&req->list);
281 		fc->active_background++;
282 		req->in.h.unique = fuse_get_unique(fc);
283 		queue_request(fc, req);
284 	}
285 }
286 
287 /*
288  * This function is called when a request is finished.  Either a reply
289  * has arrived or it was aborted (and not yet sent) or some error
290  * occurred during communication with userspace, or the device file
291  * was closed.  The requester thread is woken up (if still waiting),
292  * the 'end' callback is called if given, else the reference to the
293  * request is released
294  *
295  * Called with fc->lock, unlocks it
296  */
request_end(struct fuse_conn * fc,struct fuse_req * req)297 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
298 __releases(fc->lock)
299 {
300 	void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
301 	req->end = NULL;
302 	list_del(&req->list);
303 	list_del(&req->intr_entry);
304 	req->state = FUSE_REQ_FINISHED;
305 	if (req->background) {
306 		if (fc->num_background == fc->max_background) {
307 			fc->blocked = 0;
308 			wake_up_all(&fc->blocked_waitq);
309 		}
310 		if (fc->num_background == fc->congestion_threshold &&
311 		    fc->connected && fc->bdi_initialized) {
312 			clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
313 			clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
314 		}
315 		fc->num_background--;
316 		fc->active_background--;
317 		flush_bg_queue(fc);
318 	}
319 	spin_unlock(&fc->lock);
320 	wake_up(&req->waitq);
321 	if (end)
322 		end(fc, req);
323 	fuse_put_request(fc, req);
324 }
325 
wait_answer_interruptible(struct fuse_conn * fc,struct fuse_req * req)326 static void wait_answer_interruptible(struct fuse_conn *fc,
327 				      struct fuse_req *req)
328 __releases(fc->lock)
329 __acquires(fc->lock)
330 {
331 	if (signal_pending(current))
332 		return;
333 
334 	spin_unlock(&fc->lock);
335 	wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
336 	spin_lock(&fc->lock);
337 }
338 
queue_interrupt(struct fuse_conn * fc,struct fuse_req * req)339 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
340 {
341 	list_add_tail(&req->intr_entry, &fc->interrupts);
342 	wake_up(&fc->waitq);
343 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
344 }
345 
request_wait_answer(struct fuse_conn * fc,struct fuse_req * req)346 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
347 __releases(fc->lock)
348 __acquires(fc->lock)
349 {
350 	if (!fc->no_interrupt) {
351 		/* Any signal may interrupt this */
352 		wait_answer_interruptible(fc, req);
353 
354 		if (req->aborted)
355 			goto aborted;
356 		if (req->state == FUSE_REQ_FINISHED)
357 			return;
358 
359 		req->interrupted = 1;
360 		if (req->state == FUSE_REQ_SENT)
361 			queue_interrupt(fc, req);
362 	}
363 
364 	if (!req->force) {
365 		sigset_t oldset;
366 
367 		/* Only fatal signals may interrupt this */
368 		block_sigs(&oldset);
369 		wait_answer_interruptible(fc, req);
370 		restore_sigs(&oldset);
371 
372 		if (req->aborted)
373 			goto aborted;
374 		if (req->state == FUSE_REQ_FINISHED)
375 			return;
376 
377 		/* Request is not yet in userspace, bail out */
378 		if (req->state == FUSE_REQ_PENDING) {
379 			list_del(&req->list);
380 			__fuse_put_request(req);
381 			req->out.h.error = -EINTR;
382 			return;
383 		}
384 	}
385 
386 	/*
387 	 * Either request is already in userspace, or it was forced.
388 	 * Wait it out.
389 	 */
390 	spin_unlock(&fc->lock);
391 
392 	while (req->state != FUSE_REQ_FINISHED)
393 		wait_event_freezable(req->waitq,
394 				     req->state == FUSE_REQ_FINISHED);
395 	spin_lock(&fc->lock);
396 
397 	if (!req->aborted)
398 		return;
399 
400  aborted:
401 	BUG_ON(req->state != FUSE_REQ_FINISHED);
402 	if (req->locked) {
403 		/* This is uninterruptible sleep, because data is
404 		   being copied to/from the buffers of req.  During
405 		   locked state, there mustn't be any filesystem
406 		   operation (e.g. page fault), since that could lead
407 		   to deadlock */
408 		spin_unlock(&fc->lock);
409 		wait_event(req->waitq, !req->locked);
410 		spin_lock(&fc->lock);
411 	}
412 }
413 
fuse_request_send(struct fuse_conn * fc,struct fuse_req * req)414 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
415 {
416 	req->isreply = 1;
417 	spin_lock(&fc->lock);
418 	if (!fc->connected)
419 		req->out.h.error = -ENOTCONN;
420 	else if (fc->conn_error)
421 		req->out.h.error = -ECONNREFUSED;
422 	else {
423 		req->in.h.unique = fuse_get_unique(fc);
424 		queue_request(fc, req);
425 		/* acquire extra reference, since request is still needed
426 		   after request_end() */
427 		__fuse_get_request(req);
428 
429 		request_wait_answer(fc, req);
430 	}
431 	spin_unlock(&fc->lock);
432 }
433 EXPORT_SYMBOL_GPL(fuse_request_send);
434 
fuse_request_send_nowait_locked(struct fuse_conn * fc,struct fuse_req * req)435 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
436 					    struct fuse_req *req)
437 {
438 	req->background = 1;
439 	fc->num_background++;
440 	if (fc->num_background == fc->max_background)
441 		fc->blocked = 1;
442 	if (fc->num_background == fc->congestion_threshold &&
443 	    fc->bdi_initialized) {
444 		set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
445 		set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
446 	}
447 	list_add_tail(&req->list, &fc->bg_queue);
448 	flush_bg_queue(fc);
449 }
450 
fuse_request_send_nowait(struct fuse_conn * fc,struct fuse_req * req)451 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
452 {
453 	spin_lock(&fc->lock);
454 	if (fc->connected) {
455 		fuse_request_send_nowait_locked(fc, req);
456 		spin_unlock(&fc->lock);
457 	} else {
458 		req->out.h.error = -ENOTCONN;
459 		request_end(fc, req);
460 	}
461 }
462 
fuse_request_send_background(struct fuse_conn * fc,struct fuse_req * req)463 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
464 {
465 	req->isreply = 1;
466 	fuse_request_send_nowait(fc, req);
467 }
468 EXPORT_SYMBOL_GPL(fuse_request_send_background);
469 
fuse_request_send_notify_reply(struct fuse_conn * fc,struct fuse_req * req,u64 unique)470 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
471 					  struct fuse_req *req, u64 unique)
472 {
473 	int err = -ENODEV;
474 
475 	req->isreply = 0;
476 	req->in.h.unique = unique;
477 	spin_lock(&fc->lock);
478 	if (fc->connected) {
479 		queue_request(fc, req);
480 		err = 0;
481 	}
482 	spin_unlock(&fc->lock);
483 
484 	return err;
485 }
486 
487 /*
488  * Called under fc->lock
489  *
490  * fc->connected must have been checked previously
491  */
fuse_request_send_background_locked(struct fuse_conn * fc,struct fuse_req * req)492 void fuse_request_send_background_locked(struct fuse_conn *fc,
493 					 struct fuse_req *req)
494 {
495 	req->isreply = 1;
496 	fuse_request_send_nowait_locked(fc, req);
497 }
498 
499 /*
500  * Lock the request.  Up to the next unlock_request() there mustn't be
501  * anything that could cause a page-fault.  If the request was already
502  * aborted bail out.
503  */
lock_request(struct fuse_conn * fc,struct fuse_req * req)504 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
505 {
506 	int err = 0;
507 	if (req) {
508 		spin_lock(&fc->lock);
509 		if (req->aborted)
510 			err = -ENOENT;
511 		else
512 			req->locked = 1;
513 		spin_unlock(&fc->lock);
514 	}
515 	return err;
516 }
517 
518 /*
519  * Unlock request.  If it was aborted during being locked, the
520  * requester thread is currently waiting for it to be unlocked, so
521  * wake it up.
522  */
unlock_request(struct fuse_conn * fc,struct fuse_req * req)523 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
524 {
525 	if (req) {
526 		spin_lock(&fc->lock);
527 		req->locked = 0;
528 		if (req->aborted)
529 			wake_up(&req->waitq);
530 		spin_unlock(&fc->lock);
531 	}
532 }
533 
534 struct fuse_copy_state {
535 	struct fuse_conn *fc;
536 	int write;
537 	struct fuse_req *req;
538 	const struct iovec *iov;
539 	struct pipe_buffer *pipebufs;
540 	struct pipe_buffer *currbuf;
541 	struct pipe_inode_info *pipe;
542 	unsigned long nr_segs;
543 	unsigned long seglen;
544 	unsigned long addr;
545 	struct page *pg;
546 	void *mapaddr;
547 	void *buf;
548 	unsigned len;
549 	unsigned move_pages:1;
550 };
551 
fuse_copy_init(struct fuse_copy_state * cs,struct fuse_conn * fc,int write,const struct iovec * iov,unsigned long nr_segs)552 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
553 			   int write,
554 			   const struct iovec *iov, unsigned long nr_segs)
555 {
556 	memset(cs, 0, sizeof(*cs));
557 	cs->fc = fc;
558 	cs->write = write;
559 	cs->iov = iov;
560 	cs->nr_segs = nr_segs;
561 }
562 
563 /* Unmap and put previous page of userspace buffer */
fuse_copy_finish(struct fuse_copy_state * cs)564 static void fuse_copy_finish(struct fuse_copy_state *cs)
565 {
566 	if (cs->currbuf) {
567 		struct pipe_buffer *buf = cs->currbuf;
568 
569 		if (!cs->write) {
570 			buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
571 		} else {
572 			kunmap(buf->page);
573 			buf->len = PAGE_SIZE - cs->len;
574 		}
575 		cs->currbuf = NULL;
576 		cs->mapaddr = NULL;
577 	} else if (cs->mapaddr) {
578 		kunmap(cs->pg);
579 		if (cs->write) {
580 			flush_dcache_page(cs->pg);
581 			set_page_dirty_lock(cs->pg);
582 		}
583 		put_page(cs->pg);
584 		cs->mapaddr = NULL;
585 	}
586 }
587 
588 /*
589  * Get another pagefull of userspace buffer, and map it to kernel
590  * address space, and lock request
591  */
fuse_copy_fill(struct fuse_copy_state * cs)592 static int fuse_copy_fill(struct fuse_copy_state *cs)
593 {
594 	unsigned long offset;
595 	int err;
596 
597 	unlock_request(cs->fc, cs->req);
598 	fuse_copy_finish(cs);
599 	if (cs->pipebufs) {
600 		struct pipe_buffer *buf = cs->pipebufs;
601 
602 		if (!cs->write) {
603 			err = buf->ops->confirm(cs->pipe, buf);
604 			if (err)
605 				return err;
606 
607 			BUG_ON(!cs->nr_segs);
608 			cs->currbuf = buf;
609 			cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
610 			cs->len = buf->len;
611 			cs->buf = cs->mapaddr + buf->offset;
612 			cs->pipebufs++;
613 			cs->nr_segs--;
614 		} else {
615 			struct page *page;
616 
617 			if (cs->nr_segs == cs->pipe->buffers)
618 				return -EIO;
619 
620 			page = alloc_page(GFP_HIGHUSER);
621 			if (!page)
622 				return -ENOMEM;
623 
624 			buf->page = page;
625 			buf->offset = 0;
626 			buf->len = 0;
627 
628 			cs->currbuf = buf;
629 			cs->mapaddr = kmap(page);
630 			cs->buf = cs->mapaddr;
631 			cs->len = PAGE_SIZE;
632 			cs->pipebufs++;
633 			cs->nr_segs++;
634 		}
635 	} else {
636 		if (!cs->seglen) {
637 			BUG_ON(!cs->nr_segs);
638 			cs->seglen = cs->iov[0].iov_len;
639 			cs->addr = (unsigned long) cs->iov[0].iov_base;
640 			cs->iov++;
641 			cs->nr_segs--;
642 		}
643 		err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
644 		if (err < 0)
645 			return err;
646 		BUG_ON(err != 1);
647 		offset = cs->addr % PAGE_SIZE;
648 		cs->mapaddr = kmap(cs->pg);
649 		cs->buf = cs->mapaddr + offset;
650 		cs->len = min(PAGE_SIZE - offset, cs->seglen);
651 		cs->seglen -= cs->len;
652 		cs->addr += cs->len;
653 	}
654 
655 	return lock_request(cs->fc, cs->req);
656 }
657 
658 /* Do as much copy to/from userspace buffer as we can */
fuse_copy_do(struct fuse_copy_state * cs,void ** val,unsigned * size)659 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
660 {
661 	unsigned ncpy = min(*size, cs->len);
662 	if (val) {
663 		if (cs->write)
664 			memcpy(cs->buf, *val, ncpy);
665 		else
666 			memcpy(*val, cs->buf, ncpy);
667 		*val += ncpy;
668 	}
669 	*size -= ncpy;
670 	cs->len -= ncpy;
671 	cs->buf += ncpy;
672 	return ncpy;
673 }
674 
fuse_check_page(struct page * page)675 static int fuse_check_page(struct page *page)
676 {
677 	if (page_mapcount(page) ||
678 	    page->mapping != NULL ||
679 	    page_count(page) != 1 ||
680 	    (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
681 	     ~(1 << PG_locked |
682 	       1 << PG_referenced |
683 	       1 << PG_uptodate |
684 	       1 << PG_lru |
685 	       1 << PG_active |
686 	       1 << PG_reclaim))) {
687 		printk(KERN_WARNING "fuse: trying to steal weird page\n");
688 		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);
689 		return 1;
690 	}
691 	return 0;
692 }
693 
fuse_try_move_page(struct fuse_copy_state * cs,struct page ** pagep)694 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
695 {
696 	int err;
697 	struct page *oldpage = *pagep;
698 	struct page *newpage;
699 	struct pipe_buffer *buf = cs->pipebufs;
700 	struct address_space *mapping;
701 	pgoff_t index;
702 
703 	unlock_request(cs->fc, cs->req);
704 	fuse_copy_finish(cs);
705 
706 	err = buf->ops->confirm(cs->pipe, buf);
707 	if (err)
708 		return err;
709 
710 	BUG_ON(!cs->nr_segs);
711 	cs->currbuf = buf;
712 	cs->len = buf->len;
713 	cs->pipebufs++;
714 	cs->nr_segs--;
715 
716 	if (cs->len != PAGE_SIZE)
717 		goto out_fallback;
718 
719 	if (buf->ops->steal(cs->pipe, buf) != 0)
720 		goto out_fallback;
721 
722 	newpage = buf->page;
723 
724 	if (WARN_ON(!PageUptodate(newpage)))
725 		return -EIO;
726 
727 	ClearPageMappedToDisk(newpage);
728 
729 	if (fuse_check_page(newpage) != 0)
730 		goto out_fallback_unlock;
731 
732 	mapping = oldpage->mapping;
733 	index = oldpage->index;
734 
735 	/*
736 	 * This is a new and locked page, it shouldn't be mapped or
737 	 * have any special flags on it
738 	 */
739 	if (WARN_ON(page_mapped(oldpage)))
740 		goto out_fallback_unlock;
741 	if (WARN_ON(page_has_private(oldpage)))
742 		goto out_fallback_unlock;
743 	if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
744 		goto out_fallback_unlock;
745 	if (WARN_ON(PageMlocked(oldpage)))
746 		goto out_fallback_unlock;
747 
748 	err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
749 	if (err) {
750 		unlock_page(newpage);
751 		return err;
752 	}
753 
754 	page_cache_get(newpage);
755 
756 	if (!(buf->flags & PIPE_BUF_FLAG_LRU))
757 		lru_cache_add_file(newpage);
758 
759 	err = 0;
760 	spin_lock(&cs->fc->lock);
761 	if (cs->req->aborted)
762 		err = -ENOENT;
763 	else
764 		*pagep = newpage;
765 	spin_unlock(&cs->fc->lock);
766 
767 	if (err) {
768 		unlock_page(newpage);
769 		page_cache_release(newpage);
770 		return err;
771 	}
772 
773 	unlock_page(oldpage);
774 	page_cache_release(oldpage);
775 	cs->len = 0;
776 
777 	return 0;
778 
779 out_fallback_unlock:
780 	unlock_page(newpage);
781 out_fallback:
782 	cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
783 	cs->buf = cs->mapaddr + buf->offset;
784 
785 	err = lock_request(cs->fc, cs->req);
786 	if (err)
787 		return err;
788 
789 	return 1;
790 }
791 
fuse_ref_page(struct fuse_copy_state * cs,struct page * page,unsigned offset,unsigned count)792 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
793 			 unsigned offset, unsigned count)
794 {
795 	struct pipe_buffer *buf;
796 
797 	if (cs->nr_segs == cs->pipe->buffers)
798 		return -EIO;
799 
800 	unlock_request(cs->fc, cs->req);
801 	fuse_copy_finish(cs);
802 
803 	buf = cs->pipebufs;
804 	page_cache_get(page);
805 	buf->page = page;
806 	buf->offset = offset;
807 	buf->len = count;
808 
809 	cs->pipebufs++;
810 	cs->nr_segs++;
811 	cs->len = 0;
812 
813 	return 0;
814 }
815 
816 /*
817  * Copy a page in the request to/from the userspace buffer.  Must be
818  * done atomically
819  */
fuse_copy_page(struct fuse_copy_state * cs,struct page ** pagep,unsigned offset,unsigned count,int zeroing)820 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
821 			  unsigned offset, unsigned count, int zeroing)
822 {
823 	int err;
824 	struct page *page = *pagep;
825 
826 	if (page && zeroing && count < PAGE_SIZE)
827 		clear_highpage(page);
828 
829 	while (count) {
830 		if (cs->write && cs->pipebufs && page) {
831 			return fuse_ref_page(cs, page, offset, count);
832 		} else if (!cs->len) {
833 			if (cs->move_pages && page &&
834 			    offset == 0 && count == PAGE_SIZE) {
835 				err = fuse_try_move_page(cs, pagep);
836 				if (err <= 0)
837 					return err;
838 			} else {
839 				err = fuse_copy_fill(cs);
840 				if (err)
841 					return err;
842 			}
843 		}
844 		if (page) {
845 			void *mapaddr = kmap_atomic(page);
846 			void *buf = mapaddr + offset;
847 			offset += fuse_copy_do(cs, &buf, &count);
848 			kunmap_atomic(mapaddr);
849 		} else
850 			offset += fuse_copy_do(cs, NULL, &count);
851 	}
852 	if (page && !cs->write)
853 		flush_dcache_page(page);
854 	return 0;
855 }
856 
857 /* Copy pages in the request to/from userspace buffer */
fuse_copy_pages(struct fuse_copy_state * cs,unsigned nbytes,int zeroing)858 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
859 			   int zeroing)
860 {
861 	unsigned i;
862 	struct fuse_req *req = cs->req;
863 	unsigned offset = req->page_offset;
864 	unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
865 
866 	for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
867 		int err;
868 
869 		err = fuse_copy_page(cs, &req->pages[i], offset, count,
870 				     zeroing);
871 		if (err)
872 			return err;
873 
874 		nbytes -= count;
875 		count = min(nbytes, (unsigned) PAGE_SIZE);
876 		offset = 0;
877 	}
878 	return 0;
879 }
880 
881 /* Copy a single argument in the request to/from userspace buffer */
fuse_copy_one(struct fuse_copy_state * cs,void * val,unsigned size)882 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
883 {
884 	while (size) {
885 		if (!cs->len) {
886 			int err = fuse_copy_fill(cs);
887 			if (err)
888 				return err;
889 		}
890 		fuse_copy_do(cs, &val, &size);
891 	}
892 	return 0;
893 }
894 
895 /* Copy request arguments to/from userspace buffer */
fuse_copy_args(struct fuse_copy_state * cs,unsigned numargs,unsigned argpages,struct fuse_arg * args,int zeroing)896 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
897 			  unsigned argpages, struct fuse_arg *args,
898 			  int zeroing)
899 {
900 	int err = 0;
901 	unsigned i;
902 
903 	for (i = 0; !err && i < numargs; i++)  {
904 		struct fuse_arg *arg = &args[i];
905 		if (i == numargs - 1 && argpages)
906 			err = fuse_copy_pages(cs, arg->size, zeroing);
907 		else
908 			err = fuse_copy_one(cs, arg->value, arg->size);
909 	}
910 	return err;
911 }
912 
forget_pending(struct fuse_conn * fc)913 static int forget_pending(struct fuse_conn *fc)
914 {
915 	return fc->forget_list_head.next != NULL;
916 }
917 
request_pending(struct fuse_conn * fc)918 static int request_pending(struct fuse_conn *fc)
919 {
920 	return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
921 		forget_pending(fc);
922 }
923 
924 /* Wait until a request is available on the pending list */
request_wait(struct fuse_conn * fc)925 static void request_wait(struct fuse_conn *fc)
926 __releases(fc->lock)
927 __acquires(fc->lock)
928 {
929 	DECLARE_WAITQUEUE(wait, current);
930 
931 	add_wait_queue_exclusive(&fc->waitq, &wait);
932 	while (fc->connected && !request_pending(fc)) {
933 		set_current_state(TASK_INTERRUPTIBLE);
934 		if (signal_pending(current))
935 			break;
936 
937 		spin_unlock(&fc->lock);
938 		schedule();
939 		spin_lock(&fc->lock);
940 	}
941 	set_current_state(TASK_RUNNING);
942 	remove_wait_queue(&fc->waitq, &wait);
943 }
944 
945 /*
946  * Transfer an interrupt request to userspace
947  *
948  * Unlike other requests this is assembled on demand, without a need
949  * to allocate a separate fuse_req structure.
950  *
951  * Called with fc->lock held, releases it
952  */
fuse_read_interrupt(struct fuse_conn * fc,struct fuse_copy_state * cs,size_t nbytes,struct fuse_req * req)953 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
954 			       size_t nbytes, struct fuse_req *req)
955 __releases(fc->lock)
956 {
957 	struct fuse_in_header ih;
958 	struct fuse_interrupt_in arg;
959 	unsigned reqsize = sizeof(ih) + sizeof(arg);
960 	int err;
961 
962 	list_del_init(&req->intr_entry);
963 	req->intr_unique = fuse_get_unique(fc);
964 	memset(&ih, 0, sizeof(ih));
965 	memset(&arg, 0, sizeof(arg));
966 	ih.len = reqsize;
967 	ih.opcode = FUSE_INTERRUPT;
968 	ih.unique = req->intr_unique;
969 	arg.unique = req->in.h.unique;
970 
971 	spin_unlock(&fc->lock);
972 	if (nbytes < reqsize)
973 		return -EINVAL;
974 
975 	err = fuse_copy_one(cs, &ih, sizeof(ih));
976 	if (!err)
977 		err = fuse_copy_one(cs, &arg, sizeof(arg));
978 	fuse_copy_finish(cs);
979 
980 	return err ? err : reqsize;
981 }
982 
dequeue_forget(struct fuse_conn * fc,unsigned max,unsigned * countp)983 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
984 					       unsigned max,
985 					       unsigned *countp)
986 {
987 	struct fuse_forget_link *head = fc->forget_list_head.next;
988 	struct fuse_forget_link **newhead = &head;
989 	unsigned count;
990 
991 	for (count = 0; *newhead != NULL && count < max; count++)
992 		newhead = &(*newhead)->next;
993 
994 	fc->forget_list_head.next = *newhead;
995 	*newhead = NULL;
996 	if (fc->forget_list_head.next == NULL)
997 		fc->forget_list_tail = &fc->forget_list_head;
998 
999 	if (countp != NULL)
1000 		*countp = count;
1001 
1002 	return head;
1003 }
1004 
fuse_read_single_forget(struct fuse_conn * fc,struct fuse_copy_state * cs,size_t nbytes)1005 static int fuse_read_single_forget(struct fuse_conn *fc,
1006 				   struct fuse_copy_state *cs,
1007 				   size_t nbytes)
1008 __releases(fc->lock)
1009 {
1010 	int err;
1011 	struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1012 	struct fuse_forget_in arg = {
1013 		.nlookup = forget->forget_one.nlookup,
1014 	};
1015 	struct fuse_in_header ih = {
1016 		.opcode = FUSE_FORGET,
1017 		.nodeid = forget->forget_one.nodeid,
1018 		.unique = fuse_get_unique(fc),
1019 		.len = sizeof(ih) + sizeof(arg),
1020 	};
1021 
1022 	spin_unlock(&fc->lock);
1023 	kfree(forget);
1024 	if (nbytes < ih.len)
1025 		return -EINVAL;
1026 
1027 	err = fuse_copy_one(cs, &ih, sizeof(ih));
1028 	if (!err)
1029 		err = fuse_copy_one(cs, &arg, sizeof(arg));
1030 	fuse_copy_finish(cs);
1031 
1032 	if (err)
1033 		return err;
1034 
1035 	return ih.len;
1036 }
1037 
fuse_read_batch_forget(struct fuse_conn * fc,struct fuse_copy_state * cs,size_t nbytes)1038 static int fuse_read_batch_forget(struct fuse_conn *fc,
1039 				   struct fuse_copy_state *cs, size_t nbytes)
1040 __releases(fc->lock)
1041 {
1042 	int err;
1043 	unsigned max_forgets;
1044 	unsigned count;
1045 	struct fuse_forget_link *head;
1046 	struct fuse_batch_forget_in arg = { .count = 0 };
1047 	struct fuse_in_header ih = {
1048 		.opcode = FUSE_BATCH_FORGET,
1049 		.unique = fuse_get_unique(fc),
1050 		.len = sizeof(ih) + sizeof(arg),
1051 	};
1052 
1053 	if (nbytes < ih.len) {
1054 		spin_unlock(&fc->lock);
1055 		return -EINVAL;
1056 	}
1057 
1058 	max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1059 	head = dequeue_forget(fc, max_forgets, &count);
1060 	spin_unlock(&fc->lock);
1061 
1062 	arg.count = count;
1063 	ih.len += count * sizeof(struct fuse_forget_one);
1064 	err = fuse_copy_one(cs, &ih, sizeof(ih));
1065 	if (!err)
1066 		err = fuse_copy_one(cs, &arg, sizeof(arg));
1067 
1068 	while (head) {
1069 		struct fuse_forget_link *forget = head;
1070 
1071 		if (!err) {
1072 			err = fuse_copy_one(cs, &forget->forget_one,
1073 					    sizeof(forget->forget_one));
1074 		}
1075 		head = forget->next;
1076 		kfree(forget);
1077 	}
1078 
1079 	fuse_copy_finish(cs);
1080 
1081 	if (err)
1082 		return err;
1083 
1084 	return ih.len;
1085 }
1086 
fuse_read_forget(struct fuse_conn * fc,struct fuse_copy_state * cs,size_t nbytes)1087 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1088 			    size_t nbytes)
1089 __releases(fc->lock)
1090 {
1091 	if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1092 		return fuse_read_single_forget(fc, cs, nbytes);
1093 	else
1094 		return fuse_read_batch_forget(fc, cs, nbytes);
1095 }
1096 
1097 /*
1098  * Read a single request into the userspace filesystem's buffer.  This
1099  * function waits until a request is available, then removes it from
1100  * the pending list and copies request data to userspace buffer.  If
1101  * no reply is needed (FORGET) or request has been aborted or there
1102  * was an error during the copying then it's finished by calling
1103  * request_end().  Otherwise add it to the processing list, and set
1104  * the 'sent' flag.
1105  */
fuse_dev_do_read(struct fuse_conn * fc,struct file * file,struct fuse_copy_state * cs,size_t nbytes)1106 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1107 				struct fuse_copy_state *cs, size_t nbytes)
1108 {
1109 	int err;
1110 	struct fuse_req *req;
1111 	struct fuse_in *in;
1112 	unsigned reqsize;
1113 
1114  restart:
1115 	spin_lock(&fc->lock);
1116 	err = -EAGAIN;
1117 	if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1118 	    !request_pending(fc))
1119 		goto err_unlock;
1120 
1121 	request_wait(fc);
1122 	err = -ENODEV;
1123 	if (!fc->connected)
1124 		goto err_unlock;
1125 	err = -ERESTARTSYS;
1126 	if (!request_pending(fc))
1127 		goto err_unlock;
1128 
1129 	if (!list_empty(&fc->interrupts)) {
1130 		req = list_entry(fc->interrupts.next, struct fuse_req,
1131 				 intr_entry);
1132 		return fuse_read_interrupt(fc, cs, nbytes, req);
1133 	}
1134 
1135 	if (forget_pending(fc)) {
1136 		if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1137 			return fuse_read_forget(fc, cs, nbytes);
1138 
1139 		if (fc->forget_batch <= -8)
1140 			fc->forget_batch = 16;
1141 	}
1142 
1143 	req = list_entry(fc->pending.next, struct fuse_req, list);
1144 	req->state = FUSE_REQ_READING;
1145 	list_move(&req->list, &fc->io);
1146 
1147 	in = &req->in;
1148 	reqsize = in->h.len;
1149 	/* If request is too large, reply with an error and restart the read */
1150 	if (nbytes < reqsize) {
1151 		req->out.h.error = -EIO;
1152 		/* SETXATTR is special, since it may contain too large data */
1153 		if (in->h.opcode == FUSE_SETXATTR)
1154 			req->out.h.error = -E2BIG;
1155 		request_end(fc, req);
1156 		goto restart;
1157 	}
1158 	spin_unlock(&fc->lock);
1159 	cs->req = req;
1160 	err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1161 	if (!err)
1162 		err = fuse_copy_args(cs, in->numargs, in->argpages,
1163 				     (struct fuse_arg *) in->args, 0);
1164 	fuse_copy_finish(cs);
1165 	spin_lock(&fc->lock);
1166 	req->locked = 0;
1167 	if (req->aborted) {
1168 		request_end(fc, req);
1169 		return -ENODEV;
1170 	}
1171 	if (err) {
1172 		req->out.h.error = -EIO;
1173 		request_end(fc, req);
1174 		return err;
1175 	}
1176 	if (!req->isreply)
1177 		request_end(fc, req);
1178 	else {
1179 		req->state = FUSE_REQ_SENT;
1180 		list_move_tail(&req->list, &fc->processing);
1181 		if (req->interrupted)
1182 			queue_interrupt(fc, req);
1183 		spin_unlock(&fc->lock);
1184 	}
1185 	return reqsize;
1186 
1187  err_unlock:
1188 	spin_unlock(&fc->lock);
1189 	return err;
1190 }
1191 
fuse_dev_read(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos)1192 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1193 			      unsigned long nr_segs, loff_t pos)
1194 {
1195 	struct fuse_copy_state cs;
1196 	struct file *file = iocb->ki_filp;
1197 	struct fuse_conn *fc = fuse_get_conn(file);
1198 	if (!fc)
1199 		return -EPERM;
1200 
1201 	fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1202 
1203 	return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1204 }
1205 
fuse_dev_pipe_buf_steal(struct pipe_inode_info * pipe,struct pipe_buffer * buf)1206 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1207 				   struct pipe_buffer *buf)
1208 {
1209 	return 1;
1210 }
1211 
1212 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1213 	.can_merge = 0,
1214 	.map = generic_pipe_buf_map,
1215 	.unmap = generic_pipe_buf_unmap,
1216 	.confirm = generic_pipe_buf_confirm,
1217 	.release = generic_pipe_buf_release,
1218 	.steal = fuse_dev_pipe_buf_steal,
1219 	.get = generic_pipe_buf_get,
1220 };
1221 
fuse_dev_splice_read(struct file * in,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)1222 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1223 				    struct pipe_inode_info *pipe,
1224 				    size_t len, unsigned int flags)
1225 {
1226 	int ret;
1227 	int page_nr = 0;
1228 	int do_wakeup = 0;
1229 	struct pipe_buffer *bufs;
1230 	struct fuse_copy_state cs;
1231 	struct fuse_conn *fc = fuse_get_conn(in);
1232 	if (!fc)
1233 		return -EPERM;
1234 
1235 	bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1236 	if (!bufs)
1237 		return -ENOMEM;
1238 
1239 	fuse_copy_init(&cs, fc, 1, NULL, 0);
1240 	cs.pipebufs = bufs;
1241 	cs.pipe = pipe;
1242 	ret = fuse_dev_do_read(fc, in, &cs, len);
1243 	if (ret < 0)
1244 		goto out;
1245 
1246 	ret = 0;
1247 	pipe_lock(pipe);
1248 
1249 	if (!pipe->readers) {
1250 		send_sig(SIGPIPE, current, 0);
1251 		if (!ret)
1252 			ret = -EPIPE;
1253 		goto out_unlock;
1254 	}
1255 
1256 	if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1257 		ret = -EIO;
1258 		goto out_unlock;
1259 	}
1260 
1261 	while (page_nr < cs.nr_segs) {
1262 		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1263 		struct pipe_buffer *buf = pipe->bufs + newbuf;
1264 
1265 		buf->page = bufs[page_nr].page;
1266 		buf->offset = bufs[page_nr].offset;
1267 		buf->len = bufs[page_nr].len;
1268 		buf->ops = &fuse_dev_pipe_buf_ops;
1269 
1270 		pipe->nrbufs++;
1271 		page_nr++;
1272 		ret += buf->len;
1273 
1274 		if (pipe->inode)
1275 			do_wakeup = 1;
1276 	}
1277 
1278 out_unlock:
1279 	pipe_unlock(pipe);
1280 
1281 	if (do_wakeup) {
1282 		smp_mb();
1283 		if (waitqueue_active(&pipe->wait))
1284 			wake_up_interruptible(&pipe->wait);
1285 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1286 	}
1287 
1288 out:
1289 	for (; page_nr < cs.nr_segs; page_nr++)
1290 		page_cache_release(bufs[page_nr].page);
1291 
1292 	kfree(bufs);
1293 	return ret;
1294 }
1295 
fuse_notify_poll(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1296 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1297 			    struct fuse_copy_state *cs)
1298 {
1299 	struct fuse_notify_poll_wakeup_out outarg;
1300 	int err = -EINVAL;
1301 
1302 	if (size != sizeof(outarg))
1303 		goto err;
1304 
1305 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1306 	if (err)
1307 		goto err;
1308 
1309 	fuse_copy_finish(cs);
1310 	return fuse_notify_poll_wakeup(fc, &outarg);
1311 
1312 err:
1313 	fuse_copy_finish(cs);
1314 	return err;
1315 }
1316 
fuse_notify_inval_inode(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1317 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1318 				   struct fuse_copy_state *cs)
1319 {
1320 	struct fuse_notify_inval_inode_out outarg;
1321 	int err = -EINVAL;
1322 
1323 	if (size != sizeof(outarg))
1324 		goto err;
1325 
1326 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1327 	if (err)
1328 		goto err;
1329 	fuse_copy_finish(cs);
1330 
1331 	down_read(&fc->killsb);
1332 	err = -ENOENT;
1333 	if (fc->sb) {
1334 		err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1335 					       outarg.off, outarg.len);
1336 	}
1337 	up_read(&fc->killsb);
1338 	return err;
1339 
1340 err:
1341 	fuse_copy_finish(cs);
1342 	return err;
1343 }
1344 
fuse_notify_inval_entry(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1345 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1346 				   struct fuse_copy_state *cs)
1347 {
1348 	struct fuse_notify_inval_entry_out outarg;
1349 	int err = -ENOMEM;
1350 	char *buf;
1351 	struct qstr name;
1352 
1353 	buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1354 	if (!buf)
1355 		goto err;
1356 
1357 	err = -EINVAL;
1358 	if (size < sizeof(outarg))
1359 		goto err;
1360 
1361 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1362 	if (err)
1363 		goto err;
1364 
1365 	err = -ENAMETOOLONG;
1366 	if (outarg.namelen > FUSE_NAME_MAX)
1367 		goto err;
1368 
1369 	err = -EINVAL;
1370 	if (size != sizeof(outarg) + outarg.namelen + 1)
1371 		goto err;
1372 
1373 	name.name = buf;
1374 	name.len = outarg.namelen;
1375 	err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1376 	if (err)
1377 		goto err;
1378 	fuse_copy_finish(cs);
1379 	buf[outarg.namelen] = 0;
1380 	name.hash = full_name_hash(name.name, name.len);
1381 
1382 	down_read(&fc->killsb);
1383 	err = -ENOENT;
1384 	if (fc->sb)
1385 		err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1386 	up_read(&fc->killsb);
1387 	kfree(buf);
1388 	return err;
1389 
1390 err:
1391 	kfree(buf);
1392 	fuse_copy_finish(cs);
1393 	return err;
1394 }
1395 
fuse_notify_delete(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1396 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1397 			      struct fuse_copy_state *cs)
1398 {
1399 	struct fuse_notify_delete_out outarg;
1400 	int err = -ENOMEM;
1401 	char *buf;
1402 	struct qstr name;
1403 
1404 	buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1405 	if (!buf)
1406 		goto err;
1407 
1408 	err = -EINVAL;
1409 	if (size < sizeof(outarg))
1410 		goto err;
1411 
1412 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1413 	if (err)
1414 		goto err;
1415 
1416 	err = -ENAMETOOLONG;
1417 	if (outarg.namelen > FUSE_NAME_MAX)
1418 		goto err;
1419 
1420 	err = -EINVAL;
1421 	if (size != sizeof(outarg) + outarg.namelen + 1)
1422 		goto err;
1423 
1424 	name.name = buf;
1425 	name.len = outarg.namelen;
1426 	err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1427 	if (err)
1428 		goto err;
1429 	fuse_copy_finish(cs);
1430 	buf[outarg.namelen] = 0;
1431 	name.hash = full_name_hash(name.name, name.len);
1432 
1433 	down_read(&fc->killsb);
1434 	err = -ENOENT;
1435 	if (fc->sb)
1436 		err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1437 					       outarg.child, &name);
1438 	up_read(&fc->killsb);
1439 	kfree(buf);
1440 	return err;
1441 
1442 err:
1443 	kfree(buf);
1444 	fuse_copy_finish(cs);
1445 	return err;
1446 }
1447 
fuse_notify_store(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1448 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1449 			     struct fuse_copy_state *cs)
1450 {
1451 	struct fuse_notify_store_out outarg;
1452 	struct inode *inode;
1453 	struct address_space *mapping;
1454 	u64 nodeid;
1455 	int err;
1456 	pgoff_t index;
1457 	unsigned int offset;
1458 	unsigned int num;
1459 	loff_t file_size;
1460 	loff_t end;
1461 
1462 	err = -EINVAL;
1463 	if (size < sizeof(outarg))
1464 		goto out_finish;
1465 
1466 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1467 	if (err)
1468 		goto out_finish;
1469 
1470 	err = -EINVAL;
1471 	if (size - sizeof(outarg) != outarg.size)
1472 		goto out_finish;
1473 
1474 	nodeid = outarg.nodeid;
1475 
1476 	down_read(&fc->killsb);
1477 
1478 	err = -ENOENT;
1479 	if (!fc->sb)
1480 		goto out_up_killsb;
1481 
1482 	inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1483 	if (!inode)
1484 		goto out_up_killsb;
1485 
1486 	mapping = inode->i_mapping;
1487 	index = outarg.offset >> PAGE_CACHE_SHIFT;
1488 	offset = outarg.offset & ~PAGE_CACHE_MASK;
1489 	file_size = i_size_read(inode);
1490 	end = outarg.offset + outarg.size;
1491 	if (end > file_size) {
1492 		file_size = end;
1493 		fuse_write_update_size(inode, file_size);
1494 	}
1495 
1496 	num = outarg.size;
1497 	while (num) {
1498 		struct page *page;
1499 		unsigned int this_num;
1500 
1501 		err = -ENOMEM;
1502 		page = find_or_create_page(mapping, index,
1503 					   mapping_gfp_mask(mapping));
1504 		if (!page)
1505 			goto out_iput;
1506 
1507 		this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1508 		err = fuse_copy_page(cs, &page, offset, this_num, 0);
1509 		if (!err && offset == 0 && (num != 0 || file_size == end))
1510 			SetPageUptodate(page);
1511 		unlock_page(page);
1512 		page_cache_release(page);
1513 
1514 		if (err)
1515 			goto out_iput;
1516 
1517 		num -= this_num;
1518 		offset = 0;
1519 		index++;
1520 	}
1521 
1522 	err = 0;
1523 
1524 out_iput:
1525 	iput(inode);
1526 out_up_killsb:
1527 	up_read(&fc->killsb);
1528 out_finish:
1529 	fuse_copy_finish(cs);
1530 	return err;
1531 }
1532 
fuse_retrieve_end(struct fuse_conn * fc,struct fuse_req * req)1533 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1534 {
1535 	release_pages(req->pages, req->num_pages, 0);
1536 }
1537 
fuse_retrieve(struct fuse_conn * fc,struct inode * inode,struct fuse_notify_retrieve_out * outarg)1538 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1539 			 struct fuse_notify_retrieve_out *outarg)
1540 {
1541 	int err;
1542 	struct address_space *mapping = inode->i_mapping;
1543 	struct fuse_req *req;
1544 	pgoff_t index;
1545 	loff_t file_size;
1546 	unsigned int num;
1547 	unsigned int offset;
1548 	size_t total_len = 0;
1549 
1550 	req = fuse_get_req(fc);
1551 	if (IS_ERR(req))
1552 		return PTR_ERR(req);
1553 
1554 	offset = outarg->offset & ~PAGE_CACHE_MASK;
1555 
1556 	req->in.h.opcode = FUSE_NOTIFY_REPLY;
1557 	req->in.h.nodeid = outarg->nodeid;
1558 	req->in.numargs = 2;
1559 	req->in.argpages = 1;
1560 	req->page_offset = offset;
1561 	req->end = fuse_retrieve_end;
1562 
1563 	index = outarg->offset >> PAGE_CACHE_SHIFT;
1564 	file_size = i_size_read(inode);
1565 	num = outarg->size;
1566 	if (outarg->offset > file_size)
1567 		num = 0;
1568 	else if (outarg->offset + num > file_size)
1569 		num = file_size - outarg->offset;
1570 
1571 	while (num && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
1572 		struct page *page;
1573 		unsigned int this_num;
1574 
1575 		page = find_get_page(mapping, index);
1576 		if (!page)
1577 			break;
1578 
1579 		this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1580 		req->pages[req->num_pages] = page;
1581 		req->num_pages++;
1582 
1583 		offset = 0;
1584 		num -= this_num;
1585 		total_len += this_num;
1586 		index++;
1587 	}
1588 	req->misc.retrieve_in.offset = outarg->offset;
1589 	req->misc.retrieve_in.size = total_len;
1590 	req->in.args[0].size = sizeof(req->misc.retrieve_in);
1591 	req->in.args[0].value = &req->misc.retrieve_in;
1592 	req->in.args[1].size = total_len;
1593 
1594 	err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1595 	if (err)
1596 		fuse_retrieve_end(fc, req);
1597 
1598 	return err;
1599 }
1600 
fuse_notify_retrieve(struct fuse_conn * fc,unsigned int size,struct fuse_copy_state * cs)1601 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1602 				struct fuse_copy_state *cs)
1603 {
1604 	struct fuse_notify_retrieve_out outarg;
1605 	struct inode *inode;
1606 	int err;
1607 
1608 	err = -EINVAL;
1609 	if (size != sizeof(outarg))
1610 		goto copy_finish;
1611 
1612 	err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1613 	if (err)
1614 		goto copy_finish;
1615 
1616 	fuse_copy_finish(cs);
1617 
1618 	down_read(&fc->killsb);
1619 	err = -ENOENT;
1620 	if (fc->sb) {
1621 		u64 nodeid = outarg.nodeid;
1622 
1623 		inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1624 		if (inode) {
1625 			err = fuse_retrieve(fc, inode, &outarg);
1626 			iput(inode);
1627 		}
1628 	}
1629 	up_read(&fc->killsb);
1630 
1631 	return err;
1632 
1633 copy_finish:
1634 	fuse_copy_finish(cs);
1635 	return err;
1636 }
1637 
fuse_notify(struct fuse_conn * fc,enum fuse_notify_code code,unsigned int size,struct fuse_copy_state * cs)1638 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1639 		       unsigned int size, struct fuse_copy_state *cs)
1640 {
1641 	switch (code) {
1642 	case FUSE_NOTIFY_POLL:
1643 		return fuse_notify_poll(fc, size, cs);
1644 
1645 	case FUSE_NOTIFY_INVAL_INODE:
1646 		return fuse_notify_inval_inode(fc, size, cs);
1647 
1648 	case FUSE_NOTIFY_INVAL_ENTRY:
1649 		return fuse_notify_inval_entry(fc, size, cs);
1650 
1651 	case FUSE_NOTIFY_STORE:
1652 		return fuse_notify_store(fc, size, cs);
1653 
1654 	case FUSE_NOTIFY_RETRIEVE:
1655 		return fuse_notify_retrieve(fc, size, cs);
1656 
1657 	case FUSE_NOTIFY_DELETE:
1658 		return fuse_notify_delete(fc, size, cs);
1659 
1660 	default:
1661 		fuse_copy_finish(cs);
1662 		return -EINVAL;
1663 	}
1664 }
1665 
1666 /* Look up request on processing list by unique ID */
request_find(struct fuse_conn * fc,u64 unique)1667 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1668 {
1669 	struct list_head *entry;
1670 
1671 	list_for_each(entry, &fc->processing) {
1672 		struct fuse_req *req;
1673 		req = list_entry(entry, struct fuse_req, list);
1674 		if (req->in.h.unique == unique || req->intr_unique == unique)
1675 			return req;
1676 	}
1677 	return NULL;
1678 }
1679 
copy_out_args(struct fuse_copy_state * cs,struct fuse_out * out,unsigned nbytes)1680 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1681 			 unsigned nbytes)
1682 {
1683 	unsigned reqsize = sizeof(struct fuse_out_header);
1684 
1685 	if (out->h.error)
1686 		return nbytes != reqsize ? -EINVAL : 0;
1687 
1688 	reqsize += len_args(out->numargs, out->args);
1689 
1690 	if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1691 		return -EINVAL;
1692 	else if (reqsize > nbytes) {
1693 		struct fuse_arg *lastarg = &out->args[out->numargs-1];
1694 		unsigned diffsize = reqsize - nbytes;
1695 		if (diffsize > lastarg->size)
1696 			return -EINVAL;
1697 		lastarg->size -= diffsize;
1698 	}
1699 	return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1700 			      out->page_zeroing);
1701 }
1702 
1703 /*
1704  * Write a single reply to a request.  First the header is copied from
1705  * the write buffer.  The request is then searched on the processing
1706  * list by the unique ID found in the header.  If found, then remove
1707  * it from the list and copy the rest of the buffer to the request.
1708  * The request is finished by calling request_end()
1709  */
fuse_dev_do_write(struct fuse_conn * fc,struct fuse_copy_state * cs,size_t nbytes)1710 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1711 				 struct fuse_copy_state *cs, size_t nbytes)
1712 {
1713 	int err;
1714 	struct fuse_req *req;
1715 	struct fuse_out_header oh;
1716 
1717 	if (nbytes < sizeof(struct fuse_out_header))
1718 		return -EINVAL;
1719 
1720 	err = fuse_copy_one(cs, &oh, sizeof(oh));
1721 	if (err)
1722 		goto err_finish;
1723 
1724 	err = -EINVAL;
1725 	if (oh.len != nbytes)
1726 		goto err_finish;
1727 
1728 	/*
1729 	 * Zero oh.unique indicates unsolicited notification message
1730 	 * and error contains notification code.
1731 	 */
1732 	if (!oh.unique) {
1733 		err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1734 		return err ? err : nbytes;
1735 	}
1736 
1737 	err = -EINVAL;
1738 	if (oh.error <= -1000 || oh.error > 0)
1739 		goto err_finish;
1740 
1741 	spin_lock(&fc->lock);
1742 	err = -ENOENT;
1743 	if (!fc->connected)
1744 		goto err_unlock;
1745 
1746 	req = request_find(fc, oh.unique);
1747 	if (!req)
1748 		goto err_unlock;
1749 
1750 	if (req->aborted) {
1751 		spin_unlock(&fc->lock);
1752 		fuse_copy_finish(cs);
1753 		spin_lock(&fc->lock);
1754 		request_end(fc, req);
1755 		return -ENOENT;
1756 	}
1757 	/* Is it an interrupt reply? */
1758 	if (req->intr_unique == oh.unique) {
1759 		err = -EINVAL;
1760 		if (nbytes != sizeof(struct fuse_out_header))
1761 			goto err_unlock;
1762 
1763 		if (oh.error == -ENOSYS)
1764 			fc->no_interrupt = 1;
1765 		else if (oh.error == -EAGAIN)
1766 			queue_interrupt(fc, req);
1767 
1768 		spin_unlock(&fc->lock);
1769 		fuse_copy_finish(cs);
1770 		return nbytes;
1771 	}
1772 
1773 	req->state = FUSE_REQ_WRITING;
1774 	list_move(&req->list, &fc->io);
1775 	req->out.h = oh;
1776 	req->locked = 1;
1777 	cs->req = req;
1778 	if (!req->out.page_replace)
1779 		cs->move_pages = 0;
1780 	spin_unlock(&fc->lock);
1781 
1782 	err = copy_out_args(cs, &req->out, nbytes);
1783 	fuse_copy_finish(cs);
1784 
1785 	spin_lock(&fc->lock);
1786 	req->locked = 0;
1787 	if (!err) {
1788 		if (req->aborted)
1789 			err = -ENOENT;
1790 	} else if (!req->aborted)
1791 		req->out.h.error = -EIO;
1792 	request_end(fc, req);
1793 
1794 	return err ? err : nbytes;
1795 
1796  err_unlock:
1797 	spin_unlock(&fc->lock);
1798  err_finish:
1799 	fuse_copy_finish(cs);
1800 	return err;
1801 }
1802 
fuse_dev_write(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos)1803 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1804 			      unsigned long nr_segs, loff_t pos)
1805 {
1806 	struct fuse_copy_state cs;
1807 	struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1808 	if (!fc)
1809 		return -EPERM;
1810 
1811 	fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1812 
1813 	return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1814 }
1815 
fuse_dev_splice_write(struct pipe_inode_info * pipe,struct file * out,loff_t * ppos,size_t len,unsigned int flags)1816 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1817 				     struct file *out, loff_t *ppos,
1818 				     size_t len, unsigned int flags)
1819 {
1820 	unsigned nbuf;
1821 	unsigned idx;
1822 	struct pipe_buffer *bufs;
1823 	struct fuse_copy_state cs;
1824 	struct fuse_conn *fc;
1825 	size_t rem;
1826 	ssize_t ret;
1827 
1828 	fc = fuse_get_conn(out);
1829 	if (!fc)
1830 		return -EPERM;
1831 
1832 	bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1833 	if (!bufs)
1834 		return -ENOMEM;
1835 
1836 	pipe_lock(pipe);
1837 	nbuf = 0;
1838 	rem = 0;
1839 	for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1840 		rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1841 
1842 	ret = -EINVAL;
1843 	if (rem < len) {
1844 		pipe_unlock(pipe);
1845 		goto out;
1846 	}
1847 
1848 	rem = len;
1849 	while (rem) {
1850 		struct pipe_buffer *ibuf;
1851 		struct pipe_buffer *obuf;
1852 
1853 		BUG_ON(nbuf >= pipe->buffers);
1854 		BUG_ON(!pipe->nrbufs);
1855 		ibuf = &pipe->bufs[pipe->curbuf];
1856 		obuf = &bufs[nbuf];
1857 
1858 		if (rem >= ibuf->len) {
1859 			*obuf = *ibuf;
1860 			ibuf->ops = NULL;
1861 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1862 			pipe->nrbufs--;
1863 		} else {
1864 			ibuf->ops->get(pipe, ibuf);
1865 			*obuf = *ibuf;
1866 			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1867 			obuf->len = rem;
1868 			ibuf->offset += obuf->len;
1869 			ibuf->len -= obuf->len;
1870 		}
1871 		nbuf++;
1872 		rem -= obuf->len;
1873 	}
1874 	pipe_unlock(pipe);
1875 
1876 	fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1877 	cs.pipebufs = bufs;
1878 	cs.pipe = pipe;
1879 
1880 	if (flags & SPLICE_F_MOVE)
1881 		cs.move_pages = 1;
1882 
1883 	ret = fuse_dev_do_write(fc, &cs, len);
1884 
1885 	for (idx = 0; idx < nbuf; idx++) {
1886 		struct pipe_buffer *buf = &bufs[idx];
1887 		buf->ops->release(pipe, buf);
1888 	}
1889 out:
1890 	kfree(bufs);
1891 	return ret;
1892 }
1893 
fuse_dev_poll(struct file * file,poll_table * wait)1894 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1895 {
1896 	unsigned mask = POLLOUT | POLLWRNORM;
1897 	struct fuse_conn *fc = fuse_get_conn(file);
1898 	if (!fc)
1899 		return POLLERR;
1900 
1901 	poll_wait(file, &fc->waitq, wait);
1902 
1903 	spin_lock(&fc->lock);
1904 	if (!fc->connected)
1905 		mask = POLLERR;
1906 	else if (request_pending(fc))
1907 		mask |= POLLIN | POLLRDNORM;
1908 	spin_unlock(&fc->lock);
1909 
1910 	return mask;
1911 }
1912 
1913 /*
1914  * Abort all requests on the given list (pending or processing)
1915  *
1916  * This function releases and reacquires fc->lock
1917  */
end_requests(struct fuse_conn * fc,struct list_head * head)1918 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1919 __releases(fc->lock)
1920 __acquires(fc->lock)
1921 {
1922 	while (!list_empty(head)) {
1923 		struct fuse_req *req;
1924 		req = list_entry(head->next, struct fuse_req, list);
1925 		req->out.h.error = -ECONNABORTED;
1926 		request_end(fc, req);
1927 		spin_lock(&fc->lock);
1928 	}
1929 }
1930 
1931 /*
1932  * Abort requests under I/O
1933  *
1934  * The requests are set to aborted and finished, and the request
1935  * waiter is woken up.  This will make request_wait_answer() wait
1936  * until the request is unlocked and then return.
1937  *
1938  * If the request is asynchronous, then the end function needs to be
1939  * called after waiting for the request to be unlocked (if it was
1940  * locked).
1941  */
end_io_requests(struct fuse_conn * fc)1942 static void end_io_requests(struct fuse_conn *fc)
1943 __releases(fc->lock)
1944 __acquires(fc->lock)
1945 {
1946 	while (!list_empty(&fc->io)) {
1947 		struct fuse_req *req =
1948 			list_entry(fc->io.next, struct fuse_req, list);
1949 		void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1950 
1951 		req->aborted = 1;
1952 		req->out.h.error = -ECONNABORTED;
1953 		req->state = FUSE_REQ_FINISHED;
1954 		list_del_init(&req->list);
1955 		wake_up(&req->waitq);
1956 		if (end) {
1957 			req->end = NULL;
1958 			__fuse_get_request(req);
1959 			spin_unlock(&fc->lock);
1960 			wait_event(req->waitq, !req->locked);
1961 			end(fc, req);
1962 			fuse_put_request(fc, req);
1963 			spin_lock(&fc->lock);
1964 		}
1965 	}
1966 }
1967 
end_queued_requests(struct fuse_conn * fc)1968 static void end_queued_requests(struct fuse_conn *fc)
1969 __releases(fc->lock)
1970 __acquires(fc->lock)
1971 {
1972 	fc->max_background = UINT_MAX;
1973 	flush_bg_queue(fc);
1974 	end_requests(fc, &fc->pending);
1975 	end_requests(fc, &fc->processing);
1976 	while (forget_pending(fc))
1977 		kfree(dequeue_forget(fc, 1, NULL));
1978 }
1979 
end_polls(struct fuse_conn * fc)1980 static void end_polls(struct fuse_conn *fc)
1981 {
1982 	struct rb_node *p;
1983 
1984 	p = rb_first(&fc->polled_files);
1985 
1986 	while (p) {
1987 		struct fuse_file *ff;
1988 		ff = rb_entry(p, struct fuse_file, polled_node);
1989 		wake_up_interruptible_all(&ff->poll_wait);
1990 
1991 		p = rb_next(p);
1992 	}
1993 }
1994 
1995 /*
1996  * Abort all requests.
1997  *
1998  * Emergency exit in case of a malicious or accidental deadlock, or
1999  * just a hung filesystem.
2000  *
2001  * The same effect is usually achievable through killing the
2002  * filesystem daemon and all users of the filesystem.  The exception
2003  * is the combination of an asynchronous request and the tricky
2004  * deadlock (see Documentation/filesystems/fuse.txt).
2005  *
2006  * During the aborting, progression of requests from the pending and
2007  * processing lists onto the io list, and progression of new requests
2008  * onto the pending list is prevented by req->connected being false.
2009  *
2010  * Progression of requests under I/O to the processing list is
2011  * prevented by the req->aborted flag being true for these requests.
2012  * For this reason requests on the io list must be aborted first.
2013  */
fuse_abort_conn(struct fuse_conn * fc)2014 void fuse_abort_conn(struct fuse_conn *fc)
2015 {
2016 	spin_lock(&fc->lock);
2017 	if (fc->connected) {
2018 		fc->connected = 0;
2019 		fc->blocked = 0;
2020 		end_io_requests(fc);
2021 		end_queued_requests(fc);
2022 		end_polls(fc);
2023 		wake_up_all(&fc->waitq);
2024 		wake_up_all(&fc->blocked_waitq);
2025 		kill_fasync(&fc->fasync, SIGIO, POLL_IN);
2026 	}
2027 	spin_unlock(&fc->lock);
2028 }
2029 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2030 
fuse_dev_release(struct inode * inode,struct file * file)2031 int fuse_dev_release(struct inode *inode, struct file *file)
2032 {
2033 	struct fuse_conn *fc = fuse_get_conn(file);
2034 	if (fc) {
2035 		spin_lock(&fc->lock);
2036 		fc->connected = 0;
2037 		fc->blocked = 0;
2038 		end_queued_requests(fc);
2039 		end_polls(fc);
2040 		wake_up_all(&fc->blocked_waitq);
2041 		spin_unlock(&fc->lock);
2042 		fuse_conn_put(fc);
2043 	}
2044 
2045 	return 0;
2046 }
2047 EXPORT_SYMBOL_GPL(fuse_dev_release);
2048 
fuse_dev_fasync(int fd,struct file * file,int on)2049 static int fuse_dev_fasync(int fd, struct file *file, int on)
2050 {
2051 	struct fuse_conn *fc = fuse_get_conn(file);
2052 	if (!fc)
2053 		return -EPERM;
2054 
2055 	/* No locking - fasync_helper does its own locking */
2056 	return fasync_helper(fd, file, on, &fc->fasync);
2057 }
2058 
2059 const struct file_operations fuse_dev_operations = {
2060 	.owner		= THIS_MODULE,
2061 	.llseek		= no_llseek,
2062 	.read		= do_sync_read,
2063 	.aio_read	= fuse_dev_read,
2064 	.splice_read	= fuse_dev_splice_read,
2065 	.write		= do_sync_write,
2066 	.aio_write	= fuse_dev_write,
2067 	.splice_write	= fuse_dev_splice_write,
2068 	.poll		= fuse_dev_poll,
2069 	.release	= fuse_dev_release,
2070 	.fasync		= fuse_dev_fasync,
2071 };
2072 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2073 
2074 static struct miscdevice fuse_miscdevice = {
2075 	.minor = FUSE_MINOR,
2076 	.name  = "fuse",
2077 	.fops = &fuse_dev_operations,
2078 };
2079 
fuse_dev_init(void)2080 int __init fuse_dev_init(void)
2081 {
2082 	int err = -ENOMEM;
2083 	fuse_req_cachep = kmem_cache_create("fuse_request",
2084 					    sizeof(struct fuse_req),
2085 					    0, 0, NULL);
2086 	if (!fuse_req_cachep)
2087 		goto out;
2088 
2089 	err = misc_register(&fuse_miscdevice);
2090 	if (err)
2091 		goto out_cache_clean;
2092 
2093 	return 0;
2094 
2095  out_cache_clean:
2096 	kmem_cache_destroy(fuse_req_cachep);
2097  out:
2098 	return err;
2099 }
2100 
fuse_dev_cleanup(void)2101 void fuse_dev_cleanup(void)
2102 {
2103 	misc_deregister(&fuse_miscdevice);
2104 	kmem_cache_destroy(fuse_req_cachep);
2105 }
2106