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Merge tag 'mtd/fixes-for-5.2-final' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6/linux-2.6-arm.git] / fs / fuse / dev.c
blobea8237513dfaf3342079ded75a4f562a4de339b6
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/sched/signal.h>
15 #include <linux/uio.h>
16 #include <linux/miscdevice.h>
17 #include <linux/pagemap.h>
18 #include <linux/file.h>
19 #include <linux/slab.h>
20 #include <linux/pipe_fs_i.h>
21 #include <linux/swap.h>
22 #include <linux/splice.h>
23 #include <linux/sched.h>
24
25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
26 MODULE_ALIAS("devname:fuse");
27
28 /* Ordinary requests have even IDs, while interrupts IDs are odd */
29 #define FUSE_INT_REQ_BIT (1ULL << 0)
30 #define FUSE_REQ_ID_STEP (1ULL << 1)
31
32 static struct kmem_cache *fuse_req_cachep;
33
34 static struct fuse_dev *fuse_get_dev(struct file *file)
35 {
36 /*
37 * Lockless access is OK, because file->private data is set
38 * once during mount and is valid until the file is released.
39 */
40 return READ_ONCE(file->private_data);
41 }
42
43 static void fuse_request_init(struct fuse_req *req, struct page **pages,
44 struct fuse_page_desc *page_descs,
45 unsigned npages)
46 {
47 INIT_LIST_HEAD(&req->list);
48 INIT_LIST_HEAD(&req->intr_entry);
49 init_waitqueue_head(&req->waitq);
50 refcount_set(&req->count, 1);
51 req->pages = pages;
52 req->page_descs = page_descs;
53 req->max_pages = npages;
54 __set_bit(FR_PENDING, &req->flags);
55 }
56
57 static struct page **fuse_req_pages_alloc(unsigned int npages, gfp_t flags,
58 struct fuse_page_desc **desc)
59 {
60 struct page **pages;
61
62 pages = kzalloc(npages * (sizeof(struct page *) +
63 sizeof(struct fuse_page_desc)), flags);
64 *desc = (void *) pages + npages * sizeof(struct page *);
65
66 return pages;
67 }
68
69 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
70 {
71 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
72 if (req) {
73 struct page **pages = NULL;
74 struct fuse_page_desc *page_descs = NULL;
75
76 WARN_ON(npages > FUSE_MAX_MAX_PAGES);
77 if (npages > FUSE_REQ_INLINE_PAGES) {
78 pages = fuse_req_pages_alloc(npages, flags,
79 &page_descs);
80 if (!pages) {
81 kmem_cache_free(fuse_req_cachep, req);
82 return NULL;
83 }
84 } else if (npages) {
85 pages = req->inline_pages;
86 page_descs = req->inline_page_descs;
87 }
88
89 fuse_request_init(req, pages, page_descs, npages);
90 }
91 return req;
92 }
93
94 struct fuse_req *fuse_request_alloc(unsigned npages)
95 {
96 return __fuse_request_alloc(npages, GFP_KERNEL);
97 }
98 EXPORT_SYMBOL_GPL(fuse_request_alloc);
99
100 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
101 {
102 return __fuse_request_alloc(npages, GFP_NOFS);
103 }
104
105 static void fuse_req_pages_free(struct fuse_req *req)
106 {
107 if (req->pages != req->inline_pages)
108 kfree(req->pages);
109 }
110
111 bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req,
112 gfp_t flags)
113 {
114 struct page **pages;
115 struct fuse_page_desc *page_descs;
116 unsigned int npages = min_t(unsigned int,
117 max_t(unsigned int, req->max_pages * 2,
118 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
119 fc->max_pages);
120 WARN_ON(npages <= req->max_pages);
121
122 pages = fuse_req_pages_alloc(npages, flags, &page_descs);
123 if (!pages)
124 return false;
125
126 memcpy(pages, req->pages, sizeof(struct page *) * req->max_pages);
127 memcpy(page_descs, req->page_descs,
128 sizeof(struct fuse_page_desc) * req->max_pages);
129 fuse_req_pages_free(req);
130 req->pages = pages;
131 req->page_descs = page_descs;
132 req->max_pages = npages;
133
134 return true;
135 }
136
137 void fuse_request_free(struct fuse_req *req)
138 {
139 fuse_req_pages_free(req);
140 kmem_cache_free(fuse_req_cachep, req);
141 }
142
143 void __fuse_get_request(struct fuse_req *req)
144 {
145 refcount_inc(&req->count);
146 }
147
148 /* Must be called with > 1 refcount */
149 static void __fuse_put_request(struct fuse_req *req)
150 {
151 refcount_dec(&req->count);
152 }
153
154 void fuse_set_initialized(struct fuse_conn *fc)
155 {
156 /* Make sure stores before this are seen on another CPU */
157 smp_wmb();
158 fc->initialized = 1;
159 }
160
161 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
162 {
163 return !fc->initialized || (for_background && fc->blocked);
164 }
165
166 static void fuse_drop_waiting(struct fuse_conn *fc)
167 {
168 /*
169 * lockess check of fc->connected is okay, because atomic_dec_and_test()
170 * provides a memory barrier mached with the one in fuse_wait_aborted()
171 * to ensure no wake-up is missed.
172 */
173 if (atomic_dec_and_test(&fc->num_waiting) &&
174 !READ_ONCE(fc->connected)) {
175 /* wake up aborters */
176 wake_up_all(&fc->blocked_waitq);
177 }
178 }
179
180 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
181 bool for_background)
182 {
183 struct fuse_req *req;
184 int err;
185 atomic_inc(&fc->num_waiting);
186
187 if (fuse_block_alloc(fc, for_background)) {
188 err = -EINTR;
189 if (wait_event_killable_exclusive(fc->blocked_waitq,
190 !fuse_block_alloc(fc, for_background)))
191 goto out;
192 }
193 /* Matches smp_wmb() in fuse_set_initialized() */
194 smp_rmb();
195
196 err = -ENOTCONN;
197 if (!fc->connected)
198 goto out;
199
200 err = -ECONNREFUSED;
201 if (fc->conn_error)
202 goto out;
203
204 req = fuse_request_alloc(npages);
205 err = -ENOMEM;
206 if (!req) {
207 if (for_background)
208 wake_up(&fc->blocked_waitq);
209 goto out;
210 }
211
212 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
213 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
214 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
215
216 __set_bit(FR_WAITING, &req->flags);
217 if (for_background)
218 __set_bit(FR_BACKGROUND, &req->flags);
219
220 if (unlikely(req->in.h.uid == ((uid_t)-1) ||
221 req->in.h.gid == ((gid_t)-1))) {
222 fuse_put_request(fc, req);
223 return ERR_PTR(-EOVERFLOW);
224 }
225 return req;
226
227 out:
228 fuse_drop_waiting(fc);
229 return ERR_PTR(err);
230 }
231
232 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
233 {
234 return __fuse_get_req(fc, npages, false);
235 }
236 EXPORT_SYMBOL_GPL(fuse_get_req);
237
238 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
239 unsigned npages)
240 {
241 return __fuse_get_req(fc, npages, true);
242 }
243 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
244
245 /*
246 * Return request in fuse_file->reserved_req. However that may
247 * currently be in use. If that is the case, wait for it to become
248 * available.
249 */
250 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
251 struct file *file)
252 {
253 struct fuse_req *req = NULL;
254 struct fuse_inode *fi = get_fuse_inode(file_inode(file));
255 struct fuse_file *ff = file->private_data;
256
257 do {
258 wait_event(fc->reserved_req_waitq, ff->reserved_req);
259 spin_lock(&fi->lock);
260 if (ff->reserved_req) {
261 req = ff->reserved_req;
262 ff->reserved_req = NULL;
263 req->stolen_file = get_file(file);
264 }
265 spin_unlock(&fi->lock);
266 } while (!req);
267
268 return req;
269 }
270
271 /*
272 * Put stolen request back into fuse_file->reserved_req
273 */
274 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
275 {
276 struct file *file = req->stolen_file;
277 struct fuse_inode *fi = get_fuse_inode(file_inode(file));
278 struct fuse_file *ff = file->private_data;
279
280 WARN_ON(req->max_pages);
281 spin_lock(&fi->lock);
282 memset(req, 0, sizeof(*req));
283 fuse_request_init(req, NULL, NULL, 0);
284 BUG_ON(ff->reserved_req);
285 ff->reserved_req = req;
286 wake_up_all(&fc->reserved_req_waitq);
287 spin_unlock(&fi->lock);
288 fput(file);
289 }
290
291 /*
292 * Gets a requests for a file operation, always succeeds
293 *
294 * This is used for sending the FLUSH request, which must get to
295 * userspace, due to POSIX locks which may need to be unlocked.
296 *
297 * If allocation fails due to OOM, use the reserved request in
298 * fuse_file.
299 *
300 * This is very unlikely to deadlock accidentally, since the
301 * filesystem should not have it's own file open. If deadlock is
302 * intentional, it can still be broken by "aborting" the filesystem.
303 */
304 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
305 struct file *file)
306 {
307 struct fuse_req *req;
308
309 atomic_inc(&fc->num_waiting);
310 wait_event(fc->blocked_waitq, fc->initialized);
311 /* Matches smp_wmb() in fuse_set_initialized() */
312 smp_rmb();
313 req = fuse_request_alloc(0);
314 if (!req)
315 req = get_reserved_req(fc, file);
316
317 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
318 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
319 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
320
321 __set_bit(FR_WAITING, &req->flags);
322 __clear_bit(FR_BACKGROUND, &req->flags);
323 return req;
324 }
325
326 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
327 {
328 if (refcount_dec_and_test(&req->count)) {
329 if (test_bit(FR_BACKGROUND, &req->flags)) {
330 /*
331 * We get here in the unlikely case that a background
332 * request was allocated but not sent
333 */
334 spin_lock(&fc->bg_lock);
335 if (!fc->blocked)
336 wake_up(&fc->blocked_waitq);
337 spin_unlock(&fc->bg_lock);
338 }
339
340 if (test_bit(FR_WAITING, &req->flags)) {
341 __clear_bit(FR_WAITING, &req->flags);
342 fuse_drop_waiting(fc);
343 }
344
345 if (req->stolen_file)
346 put_reserved_req(fc, req);
347 else
348 fuse_request_free(req);
349 }
350 }
351 EXPORT_SYMBOL_GPL(fuse_put_request);
352
353 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
354 {
355 unsigned nbytes = 0;
356 unsigned i;
357
358 for (i = 0; i < numargs; i++)
359 nbytes += args[i].size;
360
361 return nbytes;
362 }
363
364 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
365 {
366 fiq->reqctr += FUSE_REQ_ID_STEP;
367 return fiq->reqctr;
368 }
369
370 static unsigned int fuse_req_hash(u64 unique)
371 {
372 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
373 }
374
375 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
376 {
377 req->in.h.len = sizeof(struct fuse_in_header) +
378 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
379 list_add_tail(&req->list, &fiq->pending);
380 wake_up_locked(&fiq->waitq);
381 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
382 }
383
384 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
385 u64 nodeid, u64 nlookup)
386 {
387 struct fuse_iqueue *fiq = &fc->iq;
388
389 forget->forget_one.nodeid = nodeid;
390 forget->forget_one.nlookup = nlookup;
391
392 spin_lock(&fiq->waitq.lock);
393 if (fiq->connected) {
394 fiq->forget_list_tail->next = forget;
395 fiq->forget_list_tail = forget;
396 wake_up_locked(&fiq->waitq);
397 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
398 } else {
399 kfree(forget);
400 }
401 spin_unlock(&fiq->waitq.lock);
402 }
403
404 static void flush_bg_queue(struct fuse_conn *fc)
405 {
406 struct fuse_iqueue *fiq = &fc->iq;
407
408 while (fc->active_background < fc->max_background &&
409 !list_empty(&fc->bg_queue)) {
410 struct fuse_req *req;
411
412 req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
413 list_del(&req->list);
414 fc->active_background++;
415 spin_lock(&fiq->waitq.lock);
416 req->in.h.unique = fuse_get_unique(fiq);
417 queue_request(fiq, req);
418 spin_unlock(&fiq->waitq.lock);
419 }
420 }
421
422 /*
423 * This function is called when a request is finished. Either a reply
424 * has arrived or it was aborted (and not yet sent) or some error
425 * occurred during communication with userspace, or the device file
426 * was closed. The requester thread is woken up (if still waiting),
427 * the 'end' callback is called if given, else the reference to the
428 * request is released
429 */
430 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
431 {
432 struct fuse_iqueue *fiq = &fc->iq;
433
434 if (test_and_set_bit(FR_FINISHED, &req->flags))
435 goto put_request;
436 /*
437 * test_and_set_bit() implies smp_mb() between bit
438 * changing and below intr_entry check. Pairs with
439 * smp_mb() from queue_interrupt().
440 */
441 if (!list_empty(&req->intr_entry)) {
442 spin_lock(&fiq->waitq.lock);
443 list_del_init(&req->intr_entry);
444 spin_unlock(&fiq->waitq.lock);
445 }
446 WARN_ON(test_bit(FR_PENDING, &req->flags));
447 WARN_ON(test_bit(FR_SENT, &req->flags));
448 if (test_bit(FR_BACKGROUND, &req->flags)) {
449 spin_lock(&fc->bg_lock);
450 clear_bit(FR_BACKGROUND, &req->flags);
451 if (fc->num_background == fc->max_background) {
452 fc->blocked = 0;
453 wake_up(&fc->blocked_waitq);
454 } else if (!fc->blocked) {
455 /*
456 * Wake up next waiter, if any. It's okay to use
457 * waitqueue_active(), as we've already synced up
458 * fc->blocked with waiters with the wake_up() call
459 * above.
460 */
461 if (waitqueue_active(&fc->blocked_waitq))
462 wake_up(&fc->blocked_waitq);
463 }
464
465 if (fc->num_background == fc->congestion_threshold && fc->sb) {
466 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
467 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
468 }
469 fc->num_background--;
470 fc->active_background--;
471 flush_bg_queue(fc);
472 spin_unlock(&fc->bg_lock);
473 } else {
474 /* Wake up waiter sleeping in request_wait_answer() */
475 wake_up(&req->waitq);
476 }
477
478 if (req->end)
479 req->end(fc, req);
480 put_request:
481 fuse_put_request(fc, req);
482 }
483
484 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
485 {
486 spin_lock(&fiq->waitq.lock);
487 /* Check for we've sent request to interrupt this req */
488 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
489 spin_unlock(&fiq->waitq.lock);
490 return -EINVAL;
491 }
492
493 if (list_empty(&req->intr_entry)) {
494 list_add_tail(&req->intr_entry, &fiq->interrupts);
495 /*
496 * Pairs with smp_mb() implied by test_and_set_bit()
497 * from request_end().
498 */
499 smp_mb();
500 if (test_bit(FR_FINISHED, &req->flags)) {
501 list_del_init(&req->intr_entry);
502 spin_unlock(&fiq->waitq.lock);
503 return 0;
504 }
505 wake_up_locked(&fiq->waitq);
506 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
507 }
508 spin_unlock(&fiq->waitq.lock);
509 return 0;
510 }
511
512 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
513 {
514 struct fuse_iqueue *fiq = &fc->iq;
515 int err;
516
517 if (!fc->no_interrupt) {
518 /* Any signal may interrupt this */
519 err = wait_event_interruptible(req->waitq,
520 test_bit(FR_FINISHED, &req->flags));
521 if (!err)
522 return;
523
524 set_bit(FR_INTERRUPTED, &req->flags);
525 /* matches barrier in fuse_dev_do_read() */
526 smp_mb__after_atomic();
527 if (test_bit(FR_SENT, &req->flags))
528 queue_interrupt(fiq, req);
529 }
530
531 if (!test_bit(FR_FORCE, &req->flags)) {
532 /* Only fatal signals may interrupt this */
533 err = wait_event_killable(req->waitq,
534 test_bit(FR_FINISHED, &req->flags));
535 if (!err)
536 return;
537
538 spin_lock(&fiq->waitq.lock);
539 /* Request is not yet in userspace, bail out */
540 if (test_bit(FR_PENDING, &req->flags)) {
541 list_del(&req->list);
542 spin_unlock(&fiq->waitq.lock);
543 __fuse_put_request(req);
544 req->out.h.error = -EINTR;
545 return;
546 }
547 spin_unlock(&fiq->waitq.lock);
548 }
549
550 /*
551 * Either request is already in userspace, or it was forced.
552 * Wait it out.
553 */
554 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
555 }
556
557 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
558 {
559 struct fuse_iqueue *fiq = &fc->iq;
560
561 BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
562 spin_lock(&fiq->waitq.lock);
563 if (!fiq->connected) {
564 spin_unlock(&fiq->waitq.lock);
565 req->out.h.error = -ENOTCONN;
566 } else {
567 req->in.h.unique = fuse_get_unique(fiq);
568 queue_request(fiq, req);
569 /* acquire extra reference, since request is still needed
570 after request_end() */
571 __fuse_get_request(req);
572 spin_unlock(&fiq->waitq.lock);
573
574 request_wait_answer(fc, req);
575 /* Pairs with smp_wmb() in request_end() */
576 smp_rmb();
577 }
578 }
579
580 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
581 {
582 __set_bit(FR_ISREPLY, &req->flags);
583 if (!test_bit(FR_WAITING, &req->flags)) {
584 __set_bit(FR_WAITING, &req->flags);
585 atomic_inc(&fc->num_waiting);
586 }
587 __fuse_request_send(fc, req);
588 }
589 EXPORT_SYMBOL_GPL(fuse_request_send);
590
591 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
592 {
593 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
594 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
595
596 if (fc->minor < 9) {
597 switch (args->in.h.opcode) {
598 case FUSE_LOOKUP:
599 case FUSE_CREATE:
600 case FUSE_MKNOD:
601 case FUSE_MKDIR:
602 case FUSE_SYMLINK:
603 case FUSE_LINK:
604 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
605 break;
606 case FUSE_GETATTR:
607 case FUSE_SETATTR:
608 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
609 break;
610 }
611 }
612 if (fc->minor < 12) {
613 switch (args->in.h.opcode) {
614 case FUSE_CREATE:
615 args->in.args[0].size = sizeof(struct fuse_open_in);
616 break;
617 case FUSE_MKNOD:
618 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
619 break;
620 }
621 }
622 }
623
624 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
625 {
626 struct fuse_req *req;
627 ssize_t ret;
628
629 req = fuse_get_req(fc, 0);
630 if (IS_ERR(req))
631 return PTR_ERR(req);
632
633 /* Needs to be done after fuse_get_req() so that fc->minor is valid */
634 fuse_adjust_compat(fc, args);
635
636 req->in.h.opcode = args->in.h.opcode;
637 req->in.h.nodeid = args->in.h.nodeid;
638 req->in.numargs = args->in.numargs;
639 memcpy(req->in.args, args->in.args,
640 args->in.numargs * sizeof(struct fuse_in_arg));
641 req->out.argvar = args->out.argvar;
642 req->out.numargs = args->out.numargs;
643 memcpy(req->out.args, args->out.args,
644 args->out.numargs * sizeof(struct fuse_arg));
645 fuse_request_send(fc, req);
646 ret = req->out.h.error;
647 if (!ret && args->out.argvar) {
648 BUG_ON(args->out.numargs != 1);
649 ret = req->out.args[0].size;
650 }
651 fuse_put_request(fc, req);
652
653 return ret;
654 }
655
656 bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req)
657 {
658 bool queued = false;
659
660 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
661 if (!test_bit(FR_WAITING, &req->flags)) {
662 __set_bit(FR_WAITING, &req->flags);
663 atomic_inc(&fc->num_waiting);
664 }
665 __set_bit(FR_ISREPLY, &req->flags);
666 spin_lock(&fc->bg_lock);
667 if (likely(fc->connected)) {
668 fc->num_background++;
669 if (fc->num_background == fc->max_background)
670 fc->blocked = 1;
671 if (fc->num_background == fc->congestion_threshold && fc->sb) {
672 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
673 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
674 }
675 list_add_tail(&req->list, &fc->bg_queue);
676 flush_bg_queue(fc);
677 queued = true;
678 }
679 spin_unlock(&fc->bg_lock);
680
681 return queued;
682 }
683
684 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
685 {
686 WARN_ON(!req->end);
687 if (!fuse_request_queue_background(fc, req)) {
688 req->out.h.error = -ENOTCONN;
689 req->end(fc, req);
690 fuse_put_request(fc, req);
691 }
692 }
693 EXPORT_SYMBOL_GPL(fuse_request_send_background);
694
695 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
696 struct fuse_req *req, u64 unique)
697 {
698 int err = -ENODEV;
699 struct fuse_iqueue *fiq = &fc->iq;
700
701 __clear_bit(FR_ISREPLY, &req->flags);
702 req->in.h.unique = unique;
703 spin_lock(&fiq->waitq.lock);
704 if (fiq->connected) {
705 queue_request(fiq, req);
706 err = 0;
707 }
708 spin_unlock(&fiq->waitq.lock);
709
710 return err;
711 }
712
713 void fuse_force_forget(struct file *file, u64 nodeid)
714 {
715 struct inode *inode = file_inode(file);
716 struct fuse_conn *fc = get_fuse_conn(inode);
717 struct fuse_req *req;
718 struct fuse_forget_in inarg;
719
720 memset(&inarg, 0, sizeof(inarg));
721 inarg.nlookup = 1;
722 req = fuse_get_req_nofail_nopages(fc, file);
723 req->in.h.opcode = FUSE_FORGET;
724 req->in.h.nodeid = nodeid;
725 req->in.numargs = 1;
726 req->in.args[0].size = sizeof(inarg);
727 req->in.args[0].value = &inarg;
728 __clear_bit(FR_ISREPLY, &req->flags);
729 __fuse_request_send(fc, req);
730 /* ignore errors */
731 fuse_put_request(fc, req);
732 }
733
734 /*
735 * Lock the request. Up to the next unlock_request() there mustn't be
736 * anything that could cause a page-fault. If the request was already
737 * aborted bail out.
738 */
739 static int lock_request(struct fuse_req *req)
740 {
741 int err = 0;
742 if (req) {
743 spin_lock(&req->waitq.lock);
744 if (test_bit(FR_ABORTED, &req->flags))
745 err = -ENOENT;
746 else
747 set_bit(FR_LOCKED, &req->flags);
748 spin_unlock(&req->waitq.lock);
749 }
750 return err;
751 }
752
753 /*
754 * Unlock request. If it was aborted while locked, caller is responsible
755 * for unlocking and ending the request.
756 */
757 static int unlock_request(struct fuse_req *req)
758 {
759 int err = 0;
760 if (req) {
761 spin_lock(&req->waitq.lock);
762 if (test_bit(FR_ABORTED, &req->flags))
763 err = -ENOENT;
764 else
765 clear_bit(FR_LOCKED, &req->flags);
766 spin_unlock(&req->waitq.lock);
767 }
768 return err;
769 }
770
771 struct fuse_copy_state {
772 int write;
773 struct fuse_req *req;
774 struct iov_iter *iter;
775 struct pipe_buffer *pipebufs;
776 struct pipe_buffer *currbuf;
777 struct pipe_inode_info *pipe;
778 unsigned long nr_segs;
779 struct page *pg;
780 unsigned len;
781 unsigned offset;
782 unsigned move_pages:1;
783 };
784
785 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
786 struct iov_iter *iter)
787 {
788 memset(cs, 0, sizeof(*cs));
789 cs->write = write;
790 cs->iter = iter;
791 }
792
793 /* Unmap and put previous page of userspace buffer */
794 static void fuse_copy_finish(struct fuse_copy_state *cs)
795 {
796 if (cs->currbuf) {
797 struct pipe_buffer *buf = cs->currbuf;
798
799 if (cs->write)
800 buf->len = PAGE_SIZE - cs->len;
801 cs->currbuf = NULL;
802 } else if (cs->pg) {
803 if (cs->write) {
804 flush_dcache_page(cs->pg);
805 set_page_dirty_lock(cs->pg);
806 }
807 put_page(cs->pg);
808 }
809 cs->pg = NULL;
810 }
811
812 /*
813 * Get another pagefull of userspace buffer, and map it to kernel
814 * address space, and lock request
815 */
816 static int fuse_copy_fill(struct fuse_copy_state *cs)
817 {
818 struct page *page;
819 int err;
820
821 err = unlock_request(cs->req);
822 if (err)
823 return err;
824
825 fuse_copy_finish(cs);
826 if (cs->pipebufs) {
827 struct pipe_buffer *buf = cs->pipebufs;
828
829 if (!cs->write) {
830 err = pipe_buf_confirm(cs->pipe, buf);
831 if (err)
832 return err;
833
834 BUG_ON(!cs->nr_segs);
835 cs->currbuf = buf;
836 cs->pg = buf->page;
837 cs->offset = buf->offset;
838 cs->len = buf->len;
839 cs->pipebufs++;
840 cs->nr_segs--;
841 } else {
842 if (cs->nr_segs == cs->pipe->buffers)
843 return -EIO;
844
845 page = alloc_page(GFP_HIGHUSER);
846 if (!page)
847 return -ENOMEM;
848
849 buf->page = page;
850 buf->offset = 0;
851 buf->len = 0;
852
853 cs->currbuf = buf;
854 cs->pg = page;
855 cs->offset = 0;
856 cs->len = PAGE_SIZE;
857 cs->pipebufs++;
858 cs->nr_segs++;
859 }
860 } else {
861 size_t off;
862 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
863 if (err < 0)
864 return err;
865 BUG_ON(!err);
866 cs->len = err;
867 cs->offset = off;
868 cs->pg = page;
869 iov_iter_advance(cs->iter, err);
870 }
871
872 return lock_request(cs->req);
873 }
874
875 /* Do as much copy to/from userspace buffer as we can */
876 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
877 {
878 unsigned ncpy = min(*size, cs->len);
879 if (val) {
880 void *pgaddr = kmap_atomic(cs->pg);
881 void *buf = pgaddr + cs->offset;
882
883 if (cs->write)
884 memcpy(buf, *val, ncpy);
885 else
886 memcpy(*val, buf, ncpy);
887
888 kunmap_atomic(pgaddr);
889 *val += ncpy;
890 }
891 *size -= ncpy;
892 cs->len -= ncpy;
893 cs->offset += ncpy;
894 return ncpy;
895 }
896
897 static int fuse_check_page(struct page *page)
898 {
899 if (page_mapcount(page) ||
900 page->mapping != NULL ||
901 page_count(page) != 1 ||
902 (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
903 ~(1 << PG_locked |
904 1 << PG_referenced |
905 1 << PG_uptodate |
906 1 << PG_lru |
907 1 << PG_active |
908 1 << PG_reclaim))) {
909 pr_warn("trying to steal weird page\n");
910 pr_warn(" 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);
911 return 1;
912 }
913 return 0;
914 }
915
916 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
917 {
918 int err;
919 struct page *oldpage = *pagep;
920 struct page *newpage;
921 struct pipe_buffer *buf = cs->pipebufs;
922
923 err = unlock_request(cs->req);
924 if (err)
925 return err;
926
927 fuse_copy_finish(cs);
928
929 err = pipe_buf_confirm(cs->pipe, buf);
930 if (err)
931 return err;
932
933 BUG_ON(!cs->nr_segs);
934 cs->currbuf = buf;
935 cs->len = buf->len;
936 cs->pipebufs++;
937 cs->nr_segs--;
938
939 if (cs->len != PAGE_SIZE)
940 goto out_fallback;
941
942 if (pipe_buf_steal(cs->pipe, buf) != 0)
943 goto out_fallback;
944
945 newpage = buf->page;
946
947 if (!PageUptodate(newpage))
948 SetPageUptodate(newpage);
949
950 ClearPageMappedToDisk(newpage);
951
952 if (fuse_check_page(newpage) != 0)
953 goto out_fallback_unlock;
954
955 /*
956 * This is a new and locked page, it shouldn't be mapped or
957 * have any special flags on it
958 */
959 if (WARN_ON(page_mapped(oldpage)))
960 goto out_fallback_unlock;
961 if (WARN_ON(page_has_private(oldpage)))
962 goto out_fallback_unlock;
963 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
964 goto out_fallback_unlock;
965 if (WARN_ON(PageMlocked(oldpage)))
966 goto out_fallback_unlock;
967
968 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
969 if (err) {
970 unlock_page(newpage);
971 return err;
972 }
973
974 get_page(newpage);
975
976 if (!(buf->flags & PIPE_BUF_FLAG_LRU))
977 lru_cache_add_file(newpage);
978
979 err = 0;
980 spin_lock(&cs->req->waitq.lock);
981 if (test_bit(FR_ABORTED, &cs->req->flags))
982 err = -ENOENT;
983 else
984 *pagep = newpage;
985 spin_unlock(&cs->req->waitq.lock);
986
987 if (err) {
988 unlock_page(newpage);
989 put_page(newpage);
990 return err;
991 }
992
993 unlock_page(oldpage);
994 put_page(oldpage);
995 cs->len = 0;
996
997 return 0;
998
999 out_fallback_unlock:
1000 unlock_page(newpage);
1001 out_fallback:
1002 cs->pg = buf->page;
1003 cs->offset = buf->offset;
1004
1005 err = lock_request(cs->req);
1006 if (err)
1007 return err;
1008
1009 return 1;
1010 }
1011
1012 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
1013 unsigned offset, unsigned count)
1014 {
1015 struct pipe_buffer *buf;
1016 int err;
1017
1018 if (cs->nr_segs == cs->pipe->buffers)
1019 return -EIO;
1020
1021 err = unlock_request(cs->req);
1022 if (err)
1023 return err;
1024
1025 fuse_copy_finish(cs);
1026
1027 buf = cs->pipebufs;
1028 get_page(page);
1029 buf->page = page;
1030 buf->offset = offset;
1031 buf->len = count;
1032
1033 cs->pipebufs++;
1034 cs->nr_segs++;
1035 cs->len = 0;
1036
1037 return 0;
1038 }
1039
1040 /*
1041 * Copy a page in the request to/from the userspace buffer. Must be
1042 * done atomically
1043 */
1044 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
1045 unsigned offset, unsigned count, int zeroing)
1046 {
1047 int err;
1048 struct page *page = *pagep;
1049
1050 if (page && zeroing && count < PAGE_SIZE)
1051 clear_highpage(page);
1052
1053 while (count) {
1054 if (cs->write && cs->pipebufs && page) {
1055 return fuse_ref_page(cs, page, offset, count);
1056 } else if (!cs->len) {
1057 if (cs->move_pages && page &&
1058 offset == 0 && count == PAGE_SIZE) {
1059 err = fuse_try_move_page(cs, pagep);
1060 if (err <= 0)
1061 return err;
1062 } else {
1063 err = fuse_copy_fill(cs);
1064 if (err)
1065 return err;
1066 }
1067 }
1068 if (page) {
1069 void *mapaddr = kmap_atomic(page);
1070 void *buf = mapaddr + offset;
1071 offset += fuse_copy_do(cs, &buf, &count);
1072 kunmap_atomic(mapaddr);
1073 } else
1074 offset += fuse_copy_do(cs, NULL, &count);
1075 }
1076 if (page && !cs->write)
1077 flush_dcache_page(page);
1078 return 0;
1079 }
1080
1081 /* Copy pages in the request to/from userspace buffer */
1082 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1083 int zeroing)
1084 {
1085 unsigned i;
1086 struct fuse_req *req = cs->req;
1087
1088 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1089 int err;
1090 unsigned offset = req->page_descs[i].offset;
1091 unsigned count = min(nbytes, req->page_descs[i].length);
1092
1093 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1094 zeroing);
1095 if (err)
1096 return err;
1097
1098 nbytes -= count;
1099 }
1100 return 0;
1101 }
1102
1103 /* Copy a single argument in the request to/from userspace buffer */
1104 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1105 {
1106 while (size) {
1107 if (!cs->len) {
1108 int err = fuse_copy_fill(cs);
1109 if (err)
1110 return err;
1111 }
1112 fuse_copy_do(cs, &val, &size);
1113 }
1114 return 0;
1115 }
1116
1117 /* Copy request arguments to/from userspace buffer */
1118 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1119 unsigned argpages, struct fuse_arg *args,
1120 int zeroing)
1121 {
1122 int err = 0;
1123 unsigned i;
1124
1125 for (i = 0; !err && i < numargs; i++) {
1126 struct fuse_arg *arg = &args[i];
1127 if (i == numargs - 1 && argpages)
1128 err = fuse_copy_pages(cs, arg->size, zeroing);
1129 else
1130 err = fuse_copy_one(cs, arg->value, arg->size);
1131 }
1132 return err;
1133 }
1134
1135 static int forget_pending(struct fuse_iqueue *fiq)
1136 {
1137 return fiq->forget_list_head.next != NULL;
1138 }
1139
1140 static int request_pending(struct fuse_iqueue *fiq)
1141 {
1142 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1143 forget_pending(fiq);
1144 }
1145
1146 /*
1147 * Transfer an interrupt request to userspace
1148 *
1149 * Unlike other requests this is assembled on demand, without a need
1150 * to allocate a separate fuse_req structure.
1151 *
1152 * Called with fiq->waitq.lock held, releases it
1153 */
1154 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1155 struct fuse_copy_state *cs,
1156 size_t nbytes, struct fuse_req *req)
1157 __releases(fiq->waitq.lock)
1158 {
1159 struct fuse_in_header ih;
1160 struct fuse_interrupt_in arg;
1161 unsigned reqsize = sizeof(ih) + sizeof(arg);
1162 int err;
1163
1164 list_del_init(&req->intr_entry);
1165 memset(&ih, 0, sizeof(ih));
1166 memset(&arg, 0, sizeof(arg));
1167 ih.len = reqsize;
1168 ih.opcode = FUSE_INTERRUPT;
1169 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1170 arg.unique = req->in.h.unique;
1171
1172 spin_unlock(&fiq->waitq.lock);
1173 if (nbytes < reqsize)
1174 return -EINVAL;
1175
1176 err = fuse_copy_one(cs, &ih, sizeof(ih));
1177 if (!err)
1178 err = fuse_copy_one(cs, &arg, sizeof(arg));
1179 fuse_copy_finish(cs);
1180
1181 return err ? err : reqsize;
1182 }
1183
1184 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1185 unsigned max,
1186 unsigned *countp)
1187 {
1188 struct fuse_forget_link *head = fiq->forget_list_head.next;
1189 struct fuse_forget_link **newhead = &head;
1190 unsigned count;
1191
1192 for (count = 0; *newhead != NULL && count < max; count++)
1193 newhead = &(*newhead)->next;
1194
1195 fiq->forget_list_head.next = *newhead;
1196 *newhead = NULL;
1197 if (fiq->forget_list_head.next == NULL)
1198 fiq->forget_list_tail = &fiq->forget_list_head;
1199
1200 if (countp != NULL)
1201 *countp = count;
1202
1203 return head;
1204 }
1205
1206 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1207 struct fuse_copy_state *cs,
1208 size_t nbytes)
1209 __releases(fiq->waitq.lock)
1210 {
1211 int err;
1212 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1213 struct fuse_forget_in arg = {
1214 .nlookup = forget->forget_one.nlookup,
1215 };
1216 struct fuse_in_header ih = {
1217 .opcode = FUSE_FORGET,
1218 .nodeid = forget->forget_one.nodeid,
1219 .unique = fuse_get_unique(fiq),
1220 .len = sizeof(ih) + sizeof(arg),
1221 };
1222
1223 spin_unlock(&fiq->waitq.lock);
1224 kfree(forget);
1225 if (nbytes < ih.len)
1226 return -EINVAL;
1227
1228 err = fuse_copy_one(cs, &ih, sizeof(ih));
1229 if (!err)
1230 err = fuse_copy_one(cs, &arg, sizeof(arg));
1231 fuse_copy_finish(cs);
1232
1233 if (err)
1234 return err;
1235
1236 return ih.len;
1237 }
1238
1239 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1240 struct fuse_copy_state *cs, size_t nbytes)
1241 __releases(fiq->waitq.lock)
1242 {
1243 int err;
1244 unsigned max_forgets;
1245 unsigned count;
1246 struct fuse_forget_link *head;
1247 struct fuse_batch_forget_in arg = { .count = 0 };
1248 struct fuse_in_header ih = {
1249 .opcode = FUSE_BATCH_FORGET,
1250 .unique = fuse_get_unique(fiq),
1251 .len = sizeof(ih) + sizeof(arg),
1252 };
1253
1254 if (nbytes < ih.len) {
1255 spin_unlock(&fiq->waitq.lock);
1256 return -EINVAL;
1257 }
1258
1259 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1260 head = dequeue_forget(fiq, max_forgets, &count);
1261 spin_unlock(&fiq->waitq.lock);
1262
1263 arg.count = count;
1264 ih.len += count * sizeof(struct fuse_forget_one);
1265 err = fuse_copy_one(cs, &ih, sizeof(ih));
1266 if (!err)
1267 err = fuse_copy_one(cs, &arg, sizeof(arg));
1268
1269 while (head) {
1270 struct fuse_forget_link *forget = head;
1271
1272 if (!err) {
1273 err = fuse_copy_one(cs, &forget->forget_one,
1274 sizeof(forget->forget_one));
1275 }
1276 head = forget->next;
1277 kfree(forget);
1278 }
1279
1280 fuse_copy_finish(cs);
1281
1282 if (err)
1283 return err;
1284
1285 return ih.len;
1286 }
1287
1288 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1289 struct fuse_copy_state *cs,
1290 size_t nbytes)
1291 __releases(fiq->waitq.lock)
1292 {
1293 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1294 return fuse_read_single_forget(fiq, cs, nbytes);
1295 else
1296 return fuse_read_batch_forget(fiq, cs, nbytes);
1297 }
1298
1299 /*
1300 * Read a single request into the userspace filesystem's buffer. This
1301 * function waits until a request is available, then removes it from
1302 * the pending list and copies request data to userspace buffer. If
1303 * no reply is needed (FORGET) or request has been aborted or there
1304 * was an error during the copying then it's finished by calling
1305 * request_end(). Otherwise add it to the processing list, and set
1306 * the 'sent' flag.
1307 */
1308 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1309 struct fuse_copy_state *cs, size_t nbytes)
1310 {
1311 ssize_t err;
1312 struct fuse_conn *fc = fud->fc;
1313 struct fuse_iqueue *fiq = &fc->iq;
1314 struct fuse_pqueue *fpq = &fud->pq;
1315 struct fuse_req *req;
1316 struct fuse_in *in;
1317 unsigned reqsize;
1318 unsigned int hash;
1319
1320 restart:
1321 spin_lock(&fiq->waitq.lock);
1322 err = -EAGAIN;
1323 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1324 !request_pending(fiq))
1325 goto err_unlock;
1326
1327 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1328 !fiq->connected || request_pending(fiq));
1329 if (err)
1330 goto err_unlock;
1331
1332 if (!fiq->connected) {
1333 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1334 goto err_unlock;
1335 }
1336
1337 if (!list_empty(&fiq->interrupts)) {
1338 req = list_entry(fiq->interrupts.next, struct fuse_req,
1339 intr_entry);
1340 return fuse_read_interrupt(fiq, cs, nbytes, req);
1341 }
1342
1343 if (forget_pending(fiq)) {
1344 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1345 return fuse_read_forget(fc, fiq, cs, nbytes);
1346
1347 if (fiq->forget_batch <= -8)
1348 fiq->forget_batch = 16;
1349 }
1350
1351 req = list_entry(fiq->pending.next, struct fuse_req, list);
1352 clear_bit(FR_PENDING, &req->flags);
1353 list_del_init(&req->list);
1354 spin_unlock(&fiq->waitq.lock);
1355
1356 in = &req->in;
1357 reqsize = in->h.len;
1358
1359 /* If request is too large, reply with an error and restart the read */
1360 if (nbytes < reqsize) {
1361 req->out.h.error = -EIO;
1362 /* SETXATTR is special, since it may contain too large data */
1363 if (in->h.opcode == FUSE_SETXATTR)
1364 req->out.h.error = -E2BIG;
1365 request_end(fc, req);
1366 goto restart;
1367 }
1368 spin_lock(&fpq->lock);
1369 list_add(&req->list, &fpq->io);
1370 spin_unlock(&fpq->lock);
1371 cs->req = req;
1372 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1373 if (!err)
1374 err = fuse_copy_args(cs, in->numargs, in->argpages,
1375 (struct fuse_arg *) in->args, 0);
1376 fuse_copy_finish(cs);
1377 spin_lock(&fpq->lock);
1378 clear_bit(FR_LOCKED, &req->flags);
1379 if (!fpq->connected) {
1380 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1381 goto out_end;
1382 }
1383 if (err) {
1384 req->out.h.error = -EIO;
1385 goto out_end;
1386 }
1387 if (!test_bit(FR_ISREPLY, &req->flags)) {
1388 err = reqsize;
1389 goto out_end;
1390 }
1391 hash = fuse_req_hash(req->in.h.unique);
1392 list_move_tail(&req->list, &fpq->processing[hash]);
1393 __fuse_get_request(req);
1394 set_bit(FR_SENT, &req->flags);
1395 spin_unlock(&fpq->lock);
1396 /* matches barrier in request_wait_answer() */
1397 smp_mb__after_atomic();
1398 if (test_bit(FR_INTERRUPTED, &req->flags))
1399 queue_interrupt(fiq, req);
1400 fuse_put_request(fc, req);
1401
1402 return reqsize;
1403
1404 out_end:
1405 if (!test_bit(FR_PRIVATE, &req->flags))
1406 list_del_init(&req->list);
1407 spin_unlock(&fpq->lock);
1408 request_end(fc, req);
1409 return err;
1410
1411 err_unlock:
1412 spin_unlock(&fiq->waitq.lock);
1413 return err;
1414 }
1415
1416 static int fuse_dev_open(struct inode *inode, struct file *file)
1417 {
1418 /*
1419 * The fuse device's file's private_data is used to hold
1420 * the fuse_conn(ection) when it is mounted, and is used to
1421 * keep track of whether the file has been mounted already.
1422 */
1423 file->private_data = NULL;
1424 return 0;
1425 }
1426
1427 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1428 {
1429 struct fuse_copy_state cs;
1430 struct file *file = iocb->ki_filp;
1431 struct fuse_dev *fud = fuse_get_dev(file);
1432
1433 if (!fud)
1434 return -EPERM;
1435
1436 if (!iter_is_iovec(to))
1437 return -EINVAL;
1438
1439 fuse_copy_init(&cs, 1, to);
1440
1441 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1442 }
1443
1444 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1445 struct pipe_inode_info *pipe,
1446 size_t len, unsigned int flags)
1447 {
1448 int total, ret;
1449 int page_nr = 0;
1450 struct pipe_buffer *bufs;
1451 struct fuse_copy_state cs;
1452 struct fuse_dev *fud = fuse_get_dev(in);
1453
1454 if (!fud)
1455 return -EPERM;
1456
1457 bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1458 GFP_KERNEL);
1459 if (!bufs)
1460 return -ENOMEM;
1461
1462 fuse_copy_init(&cs, 1, NULL);
1463 cs.pipebufs = bufs;
1464 cs.pipe = pipe;
1465 ret = fuse_dev_do_read(fud, in, &cs, len);
1466 if (ret < 0)
1467 goto out;
1468
1469 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1470 ret = -EIO;
1471 goto out;
1472 }
1473
1474 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1475 /*
1476 * Need to be careful about this. Having buf->ops in module
1477 * code can Oops if the buffer persists after module unload.
1478 */
1479 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1480 bufs[page_nr].flags = 0;
1481 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1482 if (unlikely(ret < 0))
1483 break;
1484 }
1485 if (total)
1486 ret = total;
1487 out:
1488 for (; page_nr < cs.nr_segs; page_nr++)
1489 put_page(bufs[page_nr].page);
1490
1491 kvfree(bufs);
1492 return ret;
1493 }
1494
1495 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1496 struct fuse_copy_state *cs)
1497 {
1498 struct fuse_notify_poll_wakeup_out outarg;
1499 int err = -EINVAL;
1500
1501 if (size != sizeof(outarg))
1502 goto err;
1503
1504 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1505 if (err)
1506 goto err;
1507
1508 fuse_copy_finish(cs);
1509 return fuse_notify_poll_wakeup(fc, &outarg);
1510
1511 err:
1512 fuse_copy_finish(cs);
1513 return err;
1514 }
1515
1516 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1517 struct fuse_copy_state *cs)
1518 {
1519 struct fuse_notify_inval_inode_out outarg;
1520 int err = -EINVAL;
1521
1522 if (size != sizeof(outarg))
1523 goto err;
1524
1525 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1526 if (err)
1527 goto err;
1528 fuse_copy_finish(cs);
1529
1530 down_read(&fc->killsb);
1531 err = -ENOENT;
1532 if (fc->sb) {
1533 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1534 outarg.off, outarg.len);
1535 }
1536 up_read(&fc->killsb);
1537 return err;
1538
1539 err:
1540 fuse_copy_finish(cs);
1541 return err;
1542 }
1543
1544 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1545 struct fuse_copy_state *cs)
1546 {
1547 struct fuse_notify_inval_entry_out outarg;
1548 int err = -ENOMEM;
1549 char *buf;
1550 struct qstr name;
1551
1552 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1553 if (!buf)
1554 goto err;
1555
1556 err = -EINVAL;
1557 if (size < sizeof(outarg))
1558 goto err;
1559
1560 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1561 if (err)
1562 goto err;
1563
1564 err = -ENAMETOOLONG;
1565 if (outarg.namelen > FUSE_NAME_MAX)
1566 goto err;
1567
1568 err = -EINVAL;
1569 if (size != sizeof(outarg) + outarg.namelen + 1)
1570 goto err;
1571
1572 name.name = buf;
1573 name.len = outarg.namelen;
1574 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1575 if (err)
1576 goto err;
1577 fuse_copy_finish(cs);
1578 buf[outarg.namelen] = 0;
1579
1580 down_read(&fc->killsb);
1581 err = -ENOENT;
1582 if (fc->sb)
1583 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1584 up_read(&fc->killsb);
1585 kfree(buf);
1586 return err;
1587
1588 err:
1589 kfree(buf);
1590 fuse_copy_finish(cs);
1591 return err;
1592 }
1593
1594 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1595 struct fuse_copy_state *cs)
1596 {
1597 struct fuse_notify_delete_out outarg;
1598 int err = -ENOMEM;
1599 char *buf;
1600 struct qstr name;
1601
1602 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1603 if (!buf)
1604 goto err;
1605
1606 err = -EINVAL;
1607 if (size < sizeof(outarg))
1608 goto err;
1609
1610 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1611 if (err)
1612 goto err;
1613
1614 err = -ENAMETOOLONG;
1615 if (outarg.namelen > FUSE_NAME_MAX)
1616 goto err;
1617
1618 err = -EINVAL;
1619 if (size != sizeof(outarg) + outarg.namelen + 1)
1620 goto err;
1621
1622 name.name = buf;
1623 name.len = outarg.namelen;
1624 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1625 if (err)
1626 goto err;
1627 fuse_copy_finish(cs);
1628 buf[outarg.namelen] = 0;
1629
1630 down_read(&fc->killsb);
1631 err = -ENOENT;
1632 if (fc->sb)
1633 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1634 outarg.child, &name);
1635 up_read(&fc->killsb);
1636 kfree(buf);
1637 return err;
1638
1639 err:
1640 kfree(buf);
1641 fuse_copy_finish(cs);
1642 return err;
1643 }
1644
1645 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1646 struct fuse_copy_state *cs)
1647 {
1648 struct fuse_notify_store_out outarg;
1649 struct inode *inode;
1650 struct address_space *mapping;
1651 u64 nodeid;
1652 int err;
1653 pgoff_t index;
1654 unsigned int offset;
1655 unsigned int num;
1656 loff_t file_size;
1657 loff_t end;
1658
1659 err = -EINVAL;
1660 if (size < sizeof(outarg))
1661 goto out_finish;
1662
1663 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1664 if (err)
1665 goto out_finish;
1666
1667 err = -EINVAL;
1668 if (size - sizeof(outarg) != outarg.size)
1669 goto out_finish;
1670
1671 nodeid = outarg.nodeid;
1672
1673 down_read(&fc->killsb);
1674
1675 err = -ENOENT;
1676 if (!fc->sb)
1677 goto out_up_killsb;
1678
1679 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1680 if (!inode)
1681 goto out_up_killsb;
1682
1683 mapping = inode->i_mapping;
1684 index = outarg.offset >> PAGE_SHIFT;
1685 offset = outarg.offset & ~PAGE_MASK;
1686 file_size = i_size_read(inode);
1687 end = outarg.offset + outarg.size;
1688 if (end > file_size) {
1689 file_size = end;
1690 fuse_write_update_size(inode, file_size);
1691 }
1692
1693 num = outarg.size;
1694 while (num) {
1695 struct page *page;
1696 unsigned int this_num;
1697
1698 err = -ENOMEM;
1699 page = find_or_create_page(mapping, index,
1700 mapping_gfp_mask(mapping));
1701 if (!page)
1702 goto out_iput;
1703
1704 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1705 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1706 if (!err && offset == 0 &&
1707 (this_num == PAGE_SIZE || file_size == end))
1708 SetPageUptodate(page);
1709 unlock_page(page);
1710 put_page(page);
1711
1712 if (err)
1713 goto out_iput;
1714
1715 num -= this_num;
1716 offset = 0;
1717 index++;
1718 }
1719
1720 err = 0;
1721
1722 out_iput:
1723 iput(inode);
1724 out_up_killsb:
1725 up_read(&fc->killsb);
1726 out_finish:
1727 fuse_copy_finish(cs);
1728 return err;
1729 }
1730
1731 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1732 {
1733 release_pages(req->pages, req->num_pages);
1734 }
1735
1736 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1737 struct fuse_notify_retrieve_out *outarg)
1738 {
1739 int err;
1740 struct address_space *mapping = inode->i_mapping;
1741 struct fuse_req *req;
1742 pgoff_t index;
1743 loff_t file_size;
1744 unsigned int num;
1745 unsigned int offset;
1746 size_t total_len = 0;
1747 unsigned int num_pages;
1748
1749 offset = outarg->offset & ~PAGE_MASK;
1750 file_size = i_size_read(inode);
1751
1752 num = min(outarg->size, fc->max_write);
1753 if (outarg->offset > file_size)
1754 num = 0;
1755 else if (outarg->offset + num > file_size)
1756 num = file_size - outarg->offset;
1757
1758 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1759 num_pages = min(num_pages, fc->max_pages);
1760
1761 req = fuse_get_req(fc, num_pages);
1762 if (IS_ERR(req))
1763 return PTR_ERR(req);
1764
1765 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1766 req->in.h.nodeid = outarg->nodeid;
1767 req->in.numargs = 2;
1768 req->in.argpages = 1;
1769 req->end = fuse_retrieve_end;
1770
1771 index = outarg->offset >> PAGE_SHIFT;
1772
1773 while (num && req->num_pages < num_pages) {
1774 struct page *page;
1775 unsigned int this_num;
1776
1777 page = find_get_page(mapping, index);
1778 if (!page)
1779 break;
1780
1781 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1782 req->pages[req->num_pages] = page;
1783 req->page_descs[req->num_pages].offset = offset;
1784 req->page_descs[req->num_pages].length = this_num;
1785 req->num_pages++;
1786
1787 offset = 0;
1788 num -= this_num;
1789 total_len += this_num;
1790 index++;
1791 }
1792 req->misc.retrieve_in.offset = outarg->offset;
1793 req->misc.retrieve_in.size = total_len;
1794 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1795 req->in.args[0].value = &req->misc.retrieve_in;
1796 req->in.args[1].size = total_len;
1797
1798 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1799 if (err) {
1800 fuse_retrieve_end(fc, req);
1801 fuse_put_request(fc, req);
1802 }
1803
1804 return err;
1805 }
1806
1807 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1808 struct fuse_copy_state *cs)
1809 {
1810 struct fuse_notify_retrieve_out outarg;
1811 struct inode *inode;
1812 int err;
1813
1814 err = -EINVAL;
1815 if (size != sizeof(outarg))
1816 goto copy_finish;
1817
1818 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1819 if (err)
1820 goto copy_finish;
1821
1822 fuse_copy_finish(cs);
1823
1824 down_read(&fc->killsb);
1825 err = -ENOENT;
1826 if (fc->sb) {
1827 u64 nodeid = outarg.nodeid;
1828
1829 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1830 if (inode) {
1831 err = fuse_retrieve(fc, inode, &outarg);
1832 iput(inode);
1833 }
1834 }
1835 up_read(&fc->killsb);
1836
1837 return err;
1838
1839 copy_finish:
1840 fuse_copy_finish(cs);
1841 return err;
1842 }
1843
1844 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1845 unsigned int size, struct fuse_copy_state *cs)
1846 {
1847 /* Don't try to move pages (yet) */
1848 cs->move_pages = 0;
1849
1850 switch (code) {
1851 case FUSE_NOTIFY_POLL:
1852 return fuse_notify_poll(fc, size, cs);
1853
1854 case FUSE_NOTIFY_INVAL_INODE:
1855 return fuse_notify_inval_inode(fc, size, cs);
1856
1857 case FUSE_NOTIFY_INVAL_ENTRY:
1858 return fuse_notify_inval_entry(fc, size, cs);
1859
1860 case FUSE_NOTIFY_STORE:
1861 return fuse_notify_store(fc, size, cs);
1862
1863 case FUSE_NOTIFY_RETRIEVE:
1864 return fuse_notify_retrieve(fc, size, cs);
1865
1866 case FUSE_NOTIFY_DELETE:
1867 return fuse_notify_delete(fc, size, cs);
1868
1869 default:
1870 fuse_copy_finish(cs);
1871 return -EINVAL;
1872 }
1873 }
1874
1875 /* Look up request on processing list by unique ID */
1876 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1877 {
1878 unsigned int hash = fuse_req_hash(unique);
1879 struct fuse_req *req;
1880
1881 list_for_each_entry(req, &fpq->processing[hash], list) {
1882 if (req->in.h.unique == unique)
1883 return req;
1884 }
1885 return NULL;
1886 }
1887
1888 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1889 unsigned nbytes)
1890 {
1891 unsigned reqsize = sizeof(struct fuse_out_header);
1892
1893 if (out->h.error)
1894 return nbytes != reqsize ? -EINVAL : 0;
1895
1896 reqsize += len_args(out->numargs, out->args);
1897
1898 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1899 return -EINVAL;
1900 else if (reqsize > nbytes) {
1901 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1902 unsigned diffsize = reqsize - nbytes;
1903 if (diffsize > lastarg->size)
1904 return -EINVAL;
1905 lastarg->size -= diffsize;
1906 }
1907 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1908 out->page_zeroing);
1909 }
1910
1911 /*
1912 * Write a single reply to a request. First the header is copied from
1913 * the write buffer. The request is then searched on the processing
1914 * list by the unique ID found in the header. If found, then remove
1915 * it from the list and copy the rest of the buffer to the request.
1916 * The request is finished by calling request_end()
1917 */
1918 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1919 struct fuse_copy_state *cs, size_t nbytes)
1920 {
1921 int err;
1922 struct fuse_conn *fc = fud->fc;
1923 struct fuse_pqueue *fpq = &fud->pq;
1924 struct fuse_req *req;
1925 struct fuse_out_header oh;
1926
1927 err = -EINVAL;
1928 if (nbytes < sizeof(struct fuse_out_header))
1929 goto out;
1930
1931 err = fuse_copy_one(cs, &oh, sizeof(oh));
1932 if (err)
1933 goto copy_finish;
1934
1935 err = -EINVAL;
1936 if (oh.len != nbytes)
1937 goto copy_finish;
1938
1939 /*
1940 * Zero oh.unique indicates unsolicited notification message
1941 * and error contains notification code.
1942 */
1943 if (!oh.unique) {
1944 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1945 goto out;
1946 }
1947
1948 err = -EINVAL;
1949 if (oh.error <= -1000 || oh.error > 0)
1950 goto copy_finish;
1951
1952 spin_lock(&fpq->lock);
1953 req = NULL;
1954 if (fpq->connected)
1955 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1956
1957 err = -ENOENT;
1958 if (!req) {
1959 spin_unlock(&fpq->lock);
1960 goto copy_finish;
1961 }
1962
1963 /* Is it an interrupt reply ID? */
1964 if (oh.unique & FUSE_INT_REQ_BIT) {
1965 __fuse_get_request(req);
1966 spin_unlock(&fpq->lock);
1967
1968 err = 0;
1969 if (nbytes != sizeof(struct fuse_out_header))
1970 err = -EINVAL;
1971 else if (oh.error == -ENOSYS)
1972 fc->no_interrupt = 1;
1973 else if (oh.error == -EAGAIN)
1974 err = queue_interrupt(&fc->iq, req);
1975
1976 fuse_put_request(fc, req);
1977
1978 goto copy_finish;
1979 }
1980
1981 clear_bit(FR_SENT, &req->flags);
1982 list_move(&req->list, &fpq->io);
1983 req->out.h = oh;
1984 set_bit(FR_LOCKED, &req->flags);
1985 spin_unlock(&fpq->lock);
1986 cs->req = req;
1987 if (!req->out.page_replace)
1988 cs->move_pages = 0;
1989
1990 err = copy_out_args(cs, &req->out, nbytes);
1991 fuse_copy_finish(cs);
1992
1993 spin_lock(&fpq->lock);
1994 clear_bit(FR_LOCKED, &req->flags);
1995 if (!fpq->connected)
1996 err = -ENOENT;
1997 else if (err)
1998 req->out.h.error = -EIO;
1999 if (!test_bit(FR_PRIVATE, &req->flags))
2000 list_del_init(&req->list);
2001 spin_unlock(&fpq->lock);
2002
2003 request_end(fc, req);
2004 out:
2005 return err ? err : nbytes;
2006
2007 copy_finish:
2008 fuse_copy_finish(cs);
2009 goto out;
2010 }
2011
2012 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
2013 {
2014 struct fuse_copy_state cs;
2015 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
2016
2017 if (!fud)
2018 return -EPERM;
2019
2020 if (!iter_is_iovec(from))
2021 return -EINVAL;
2022
2023 fuse_copy_init(&cs, 0, from);
2024
2025 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
2026 }
2027
2028 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
2029 struct file *out, loff_t *ppos,
2030 size_t len, unsigned int flags)
2031 {
2032 unsigned nbuf;
2033 unsigned idx;
2034 struct pipe_buffer *bufs;
2035 struct fuse_copy_state cs;
2036 struct fuse_dev *fud;
2037 size_t rem;
2038 ssize_t ret;
2039
2040 fud = fuse_get_dev(out);
2041 if (!fud)
2042 return -EPERM;
2043
2044 pipe_lock(pipe);
2045
2046 bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer),
2047 GFP_KERNEL);
2048 if (!bufs) {
2049 pipe_unlock(pipe);
2050 return -ENOMEM;
2051 }
2052
2053 nbuf = 0;
2054 rem = 0;
2055 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
2056 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
2057
2058 ret = -EINVAL;
2059 if (rem < len)
2060 goto out_free;
2061
2062 rem = len;
2063 while (rem) {
2064 struct pipe_buffer *ibuf;
2065 struct pipe_buffer *obuf;
2066
2067 BUG_ON(nbuf >= pipe->buffers);
2068 BUG_ON(!pipe->nrbufs);
2069 ibuf = &pipe->bufs[pipe->curbuf];
2070 obuf = &bufs[nbuf];
2071
2072 if (rem >= ibuf->len) {
2073 *obuf = *ibuf;
2074 ibuf->ops = NULL;
2075 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2076 pipe->nrbufs--;
2077 } else {
2078 if (!pipe_buf_get(pipe, ibuf))
2079 goto out_free;
2080
2081 *obuf = *ibuf;
2082 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2083 obuf->len = rem;
2084 ibuf->offset += obuf->len;
2085 ibuf->len -= obuf->len;
2086 }
2087 nbuf++;
2088 rem -= obuf->len;
2089 }
2090 pipe_unlock(pipe);
2091
2092 fuse_copy_init(&cs, 0, NULL);
2093 cs.pipebufs = bufs;
2094 cs.nr_segs = nbuf;
2095 cs.pipe = pipe;
2096
2097 if (flags & SPLICE_F_MOVE)
2098 cs.move_pages = 1;
2099
2100 ret = fuse_dev_do_write(fud, &cs, len);
2101
2102 pipe_lock(pipe);
2103 out_free:
2104 for (idx = 0; idx < nbuf; idx++)
2105 pipe_buf_release(pipe, &bufs[idx]);
2106 pipe_unlock(pipe);
2107
2108 kvfree(bufs);
2109 return ret;
2110 }
2111
2112 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2113 {
2114 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2115 struct fuse_iqueue *fiq;
2116 struct fuse_dev *fud = fuse_get_dev(file);
2117
2118 if (!fud)
2119 return EPOLLERR;
2120
2121 fiq = &fud->fc->iq;
2122 poll_wait(file, &fiq->waitq, wait);
2123
2124 spin_lock(&fiq->waitq.lock);
2125 if (!fiq->connected)
2126 mask = EPOLLERR;
2127 else if (request_pending(fiq))
2128 mask |= EPOLLIN | EPOLLRDNORM;
2129 spin_unlock(&fiq->waitq.lock);
2130
2131 return mask;
2132 }
2133
2134 /* Abort all requests on the given list (pending or processing) */
2135 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2136 {
2137 while (!list_empty(head)) {
2138 struct fuse_req *req;
2139 req = list_entry(head->next, struct fuse_req, list);
2140 req->out.h.error = -ECONNABORTED;
2141 clear_bit(FR_SENT, &req->flags);
2142 list_del_init(&req->list);
2143 request_end(fc, req);
2144 }
2145 }
2146
2147 static void end_polls(struct fuse_conn *fc)
2148 {
2149 struct rb_node *p;
2150
2151 p = rb_first(&fc->polled_files);
2152
2153 while (p) {
2154 struct fuse_file *ff;
2155 ff = rb_entry(p, struct fuse_file, polled_node);
2156 wake_up_interruptible_all(&ff->poll_wait);
2157
2158 p = rb_next(p);
2159 }
2160 }
2161
2162 /*
2163 * Abort all requests.
2164 *
2165 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2166 * filesystem.
2167 *
2168 * The same effect is usually achievable through killing the filesystem daemon
2169 * and all users of the filesystem. The exception is the combination of an
2170 * asynchronous request and the tricky deadlock (see
2171 * Documentation/filesystems/fuse.txt).
2172 *
2173 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2174 * requests, they should be finished off immediately. Locked requests will be
2175 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2176 * requests. It is possible that some request will finish before we can. This
2177 * is OK, the request will in that case be removed from the list before we touch
2178 * it.
2179 */
2180 void fuse_abort_conn(struct fuse_conn *fc)
2181 {
2182 struct fuse_iqueue *fiq = &fc->iq;
2183
2184 spin_lock(&fc->lock);
2185 if (fc->connected) {
2186 struct fuse_dev *fud;
2187 struct fuse_req *req, *next;
2188 LIST_HEAD(to_end);
2189 unsigned int i;
2190
2191 /* Background queuing checks fc->connected under bg_lock */
2192 spin_lock(&fc->bg_lock);
2193 fc->connected = 0;
2194 spin_unlock(&fc->bg_lock);
2195
2196 fuse_set_initialized(fc);
2197 list_for_each_entry(fud, &fc->devices, entry) {
2198 struct fuse_pqueue *fpq = &fud->pq;
2199
2200 spin_lock(&fpq->lock);
2201 fpq->connected = 0;
2202 list_for_each_entry_safe(req, next, &fpq->io, list) {
2203 req->out.h.error = -ECONNABORTED;
2204 spin_lock(&req->waitq.lock);
2205 set_bit(FR_ABORTED, &req->flags);
2206 if (!test_bit(FR_LOCKED, &req->flags)) {
2207 set_bit(FR_PRIVATE, &req->flags);
2208 __fuse_get_request(req);
2209 list_move(&req->list, &to_end);
2210 }
2211 spin_unlock(&req->waitq.lock);
2212 }
2213 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2214 list_splice_tail_init(&fpq->processing[i],
2215 &to_end);
2216 spin_unlock(&fpq->lock);
2217 }
2218 spin_lock(&fc->bg_lock);
2219 fc->blocked = 0;
2220 fc->max_background = UINT_MAX;
2221 flush_bg_queue(fc);
2222 spin_unlock(&fc->bg_lock);
2223
2224 spin_lock(&fiq->waitq.lock);
2225 fiq->connected = 0;
2226 list_for_each_entry(req, &fiq->pending, list)
2227 clear_bit(FR_PENDING, &req->flags);
2228 list_splice_tail_init(&fiq->pending, &to_end);
2229 while (forget_pending(fiq))
2230 kfree(dequeue_forget(fiq, 1, NULL));
2231 wake_up_all_locked(&fiq->waitq);
2232 spin_unlock(&fiq->waitq.lock);
2233 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2234 end_polls(fc);
2235 wake_up_all(&fc->blocked_waitq);
2236 spin_unlock(&fc->lock);
2237
2238 end_requests(fc, &to_end);
2239 } else {
2240 spin_unlock(&fc->lock);
2241 }
2242 }
2243 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2244
2245 void fuse_wait_aborted(struct fuse_conn *fc)
2246 {
2247 /* matches implicit memory barrier in fuse_drop_waiting() */
2248 smp_mb();
2249 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2250 }
2251
2252 int fuse_dev_release(struct inode *inode, struct file *file)
2253 {
2254 struct fuse_dev *fud = fuse_get_dev(file);
2255
2256 if (fud) {
2257 struct fuse_conn *fc = fud->fc;
2258 struct fuse_pqueue *fpq = &fud->pq;
2259 LIST_HEAD(to_end);
2260 unsigned int i;
2261
2262 spin_lock(&fpq->lock);
2263 WARN_ON(!list_empty(&fpq->io));
2264 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2265 list_splice_init(&fpq->processing[i], &to_end);
2266 spin_unlock(&fpq->lock);
2267
2268 end_requests(fc, &to_end);
2269
2270 /* Are we the last open device? */
2271 if (atomic_dec_and_test(&fc->dev_count)) {
2272 WARN_ON(fc->iq.fasync != NULL);
2273 fuse_abort_conn(fc);
2274 }
2275 fuse_dev_free(fud);
2276 }
2277 return 0;
2278 }
2279 EXPORT_SYMBOL_GPL(fuse_dev_release);
2280
2281 static int fuse_dev_fasync(int fd, struct file *file, int on)
2282 {
2283 struct fuse_dev *fud = fuse_get_dev(file);
2284
2285 if (!fud)
2286 return -EPERM;
2287
2288 /* No locking - fasync_helper does its own locking */
2289 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2290 }
2291
2292 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2293 {
2294 struct fuse_dev *fud;
2295
2296 if (new->private_data)
2297 return -EINVAL;
2298
2299 fud = fuse_dev_alloc(fc);
2300 if (!fud)
2301 return -ENOMEM;
2302
2303 new->private_data = fud;
2304 atomic_inc(&fc->dev_count);
2305
2306 return 0;
2307 }
2308
2309 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2310 unsigned long arg)
2311 {
2312 int err = -ENOTTY;
2313
2314 if (cmd == FUSE_DEV_IOC_CLONE) {
2315 int oldfd;
2316
2317 err = -EFAULT;
2318 if (!get_user(oldfd, (__u32 __user *) arg)) {
2319 struct file *old = fget(oldfd);
2320
2321 err = -EINVAL;
2322 if (old) {
2323 struct fuse_dev *fud = NULL;
2324
2325 /*
2326 * Check against file->f_op because CUSE
2327 * uses the same ioctl handler.
2328 */
2329 if (old->f_op == file->f_op &&
2330 old->f_cred->user_ns == file->f_cred->user_ns)
2331 fud = fuse_get_dev(old);
2332
2333 if (fud) {
2334 mutex_lock(&fuse_mutex);
2335 err = fuse_device_clone(fud->fc, file);
2336 mutex_unlock(&fuse_mutex);
2337 }
2338 fput(old);
2339 }
2340 }
2341 }
2342 return err;
2343 }
2344
2345 const struct file_operations fuse_dev_operations = {
2346 .owner = THIS_MODULE,
2347 .open = fuse_dev_open,
2348 .llseek = no_llseek,
2349 .read_iter = fuse_dev_read,
2350 .splice_read = fuse_dev_splice_read,
2351 .write_iter = fuse_dev_write,
2352 .splice_write = fuse_dev_splice_write,
2353 .poll = fuse_dev_poll,
2354 .release = fuse_dev_release,
2355 .fasync = fuse_dev_fasync,
2356 .unlocked_ioctl = fuse_dev_ioctl,
2357 .compat_ioctl = fuse_dev_ioctl,
2358 };
2359 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2360
2361 static struct miscdevice fuse_miscdevice = {
2362 .minor = FUSE_MINOR,
2363 .name = "fuse",
2364 .fops = &fuse_dev_operations,
2365 };
2366
2367 int __init fuse_dev_init(void)
2368 {
2369 int err = -ENOMEM;
2370 fuse_req_cachep = kmem_cache_create("fuse_request",
2371 sizeof(struct fuse_req),
2372 0, 0, NULL);
2373 if (!fuse_req_cachep)
2374 goto out;
2375
2376 err = misc_register(&fuse_miscdevice);
2377 if (err)
2378 goto out_cache_clean;
2379
2380 return 0;
2381
2382 out_cache_clean:
2383 kmem_cache_destroy(fuse_req_cachep);
2384 out:
2385 return err;
2386 }
2387
2388 void fuse_dev_cleanup(void)
2389 {
2390 misc_deregister(&fuse_miscdevice);
2391 kmem_cache_destroy(fuse_req_cachep);
2392 }
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