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Merge tag 'powerpc-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...
[mirror_ubuntu-hirsute-kernel.git] / fs / fuse / dev.c
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/poll.h>
14 #include <linux/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 /*
1321 * Require sane minimum read buffer - that has capacity for fixed part
1322 * of any request header + negotated max_write room for data. If the
1323 * requirement is not satisfied return EINVAL to the filesystem server
1324 * to indicate that it is not following FUSE server/client contract.
1325 * Don't dequeue / abort any request.
1326 */
1327 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 4096 + fc->max_write))
1328 return -EINVAL;
1329
1330 restart:
1331 spin_lock(&fiq->waitq.lock);
1332 err = -EAGAIN;
1333 if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1334 !request_pending(fiq))
1335 goto err_unlock;
1336
1337 err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1338 !fiq->connected || request_pending(fiq));
1339 if (err)
1340 goto err_unlock;
1341
1342 if (!fiq->connected) {
1343 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1344 goto err_unlock;
1345 }
1346
1347 if (!list_empty(&fiq->interrupts)) {
1348 req = list_entry(fiq->interrupts.next, struct fuse_req,
1349 intr_entry);
1350 return fuse_read_interrupt(fiq, cs, nbytes, req);
1351 }
1352
1353 if (forget_pending(fiq)) {
1354 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1355 return fuse_read_forget(fc, fiq, cs, nbytes);
1356
1357 if (fiq->forget_batch <= -8)
1358 fiq->forget_batch = 16;
1359 }
1360
1361 req = list_entry(fiq->pending.next, struct fuse_req, list);
1362 clear_bit(FR_PENDING, &req->flags);
1363 list_del_init(&req->list);
1364 spin_unlock(&fiq->waitq.lock);
1365
1366 in = &req->in;
1367 reqsize = in->h.len;
1368
1369 /* If request is too large, reply with an error and restart the read */
1370 if (nbytes < reqsize) {
1371 req->out.h.error = -EIO;
1372 /* SETXATTR is special, since it may contain too large data */
1373 if (in->h.opcode == FUSE_SETXATTR)
1374 req->out.h.error = -E2BIG;
1375 request_end(fc, req);
1376 goto restart;
1377 }
1378 spin_lock(&fpq->lock);
1379 list_add(&req->list, &fpq->io);
1380 spin_unlock(&fpq->lock);
1381 cs->req = req;
1382 err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1383 if (!err)
1384 err = fuse_copy_args(cs, in->numargs, in->argpages,
1385 (struct fuse_arg *) in->args, 0);
1386 fuse_copy_finish(cs);
1387 spin_lock(&fpq->lock);
1388 clear_bit(FR_LOCKED, &req->flags);
1389 if (!fpq->connected) {
1390 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1391 goto out_end;
1392 }
1393 if (err) {
1394 req->out.h.error = -EIO;
1395 goto out_end;
1396 }
1397 if (!test_bit(FR_ISREPLY, &req->flags)) {
1398 err = reqsize;
1399 goto out_end;
1400 }
1401 hash = fuse_req_hash(req->in.h.unique);
1402 list_move_tail(&req->list, &fpq->processing[hash]);
1403 __fuse_get_request(req);
1404 set_bit(FR_SENT, &req->flags);
1405 spin_unlock(&fpq->lock);
1406 /* matches barrier in request_wait_answer() */
1407 smp_mb__after_atomic();
1408 if (test_bit(FR_INTERRUPTED, &req->flags))
1409 queue_interrupt(fiq, req);
1410 fuse_put_request(fc, req);
1411
1412 return reqsize;
1413
1414 out_end:
1415 if (!test_bit(FR_PRIVATE, &req->flags))
1416 list_del_init(&req->list);
1417 spin_unlock(&fpq->lock);
1418 request_end(fc, req);
1419 return err;
1420
1421 err_unlock:
1422 spin_unlock(&fiq->waitq.lock);
1423 return err;
1424 }
1425
1426 static int fuse_dev_open(struct inode *inode, struct file *file)
1427 {
1428 /*
1429 * The fuse device's file's private_data is used to hold
1430 * the fuse_conn(ection) when it is mounted, and is used to
1431 * keep track of whether the file has been mounted already.
1432 */
1433 file->private_data = NULL;
1434 return 0;
1435 }
1436
1437 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1438 {
1439 struct fuse_copy_state cs;
1440 struct file *file = iocb->ki_filp;
1441 struct fuse_dev *fud = fuse_get_dev(file);
1442
1443 if (!fud)
1444 return -EPERM;
1445
1446 if (!iter_is_iovec(to))
1447 return -EINVAL;
1448
1449 fuse_copy_init(&cs, 1, to);
1450
1451 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1452 }
1453
1454 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1455 struct pipe_inode_info *pipe,
1456 size_t len, unsigned int flags)
1457 {
1458 int total, ret;
1459 int page_nr = 0;
1460 struct pipe_buffer *bufs;
1461 struct fuse_copy_state cs;
1462 struct fuse_dev *fud = fuse_get_dev(in);
1463
1464 if (!fud)
1465 return -EPERM;
1466
1467 bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1468 GFP_KERNEL);
1469 if (!bufs)
1470 return -ENOMEM;
1471
1472 fuse_copy_init(&cs, 1, NULL);
1473 cs.pipebufs = bufs;
1474 cs.pipe = pipe;
1475 ret = fuse_dev_do_read(fud, in, &cs, len);
1476 if (ret < 0)
1477 goto out;
1478
1479 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1480 ret = -EIO;
1481 goto out;
1482 }
1483
1484 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1485 /*
1486 * Need to be careful about this. Having buf->ops in module
1487 * code can Oops if the buffer persists after module unload.
1488 */
1489 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1490 bufs[page_nr].flags = 0;
1491 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1492 if (unlikely(ret < 0))
1493 break;
1494 }
1495 if (total)
1496 ret = total;
1497 out:
1498 for (; page_nr < cs.nr_segs; page_nr++)
1499 put_page(bufs[page_nr].page);
1500
1501 kvfree(bufs);
1502 return ret;
1503 }
1504
1505 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1506 struct fuse_copy_state *cs)
1507 {
1508 struct fuse_notify_poll_wakeup_out outarg;
1509 int err = -EINVAL;
1510
1511 if (size != sizeof(outarg))
1512 goto err;
1513
1514 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1515 if (err)
1516 goto err;
1517
1518 fuse_copy_finish(cs);
1519 return fuse_notify_poll_wakeup(fc, &outarg);
1520
1521 err:
1522 fuse_copy_finish(cs);
1523 return err;
1524 }
1525
1526 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1527 struct fuse_copy_state *cs)
1528 {
1529 struct fuse_notify_inval_inode_out outarg;
1530 int err = -EINVAL;
1531
1532 if (size != sizeof(outarg))
1533 goto err;
1534
1535 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1536 if (err)
1537 goto err;
1538 fuse_copy_finish(cs);
1539
1540 down_read(&fc->killsb);
1541 err = -ENOENT;
1542 if (fc->sb) {
1543 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1544 outarg.off, outarg.len);
1545 }
1546 up_read(&fc->killsb);
1547 return err;
1548
1549 err:
1550 fuse_copy_finish(cs);
1551 return err;
1552 }
1553
1554 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1555 struct fuse_copy_state *cs)
1556 {
1557 struct fuse_notify_inval_entry_out outarg;
1558 int err = -ENOMEM;
1559 char *buf;
1560 struct qstr name;
1561
1562 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1563 if (!buf)
1564 goto err;
1565
1566 err = -EINVAL;
1567 if (size < sizeof(outarg))
1568 goto err;
1569
1570 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1571 if (err)
1572 goto err;
1573
1574 err = -ENAMETOOLONG;
1575 if (outarg.namelen > FUSE_NAME_MAX)
1576 goto err;
1577
1578 err = -EINVAL;
1579 if (size != sizeof(outarg) + outarg.namelen + 1)
1580 goto err;
1581
1582 name.name = buf;
1583 name.len = outarg.namelen;
1584 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1585 if (err)
1586 goto err;
1587 fuse_copy_finish(cs);
1588 buf[outarg.namelen] = 0;
1589
1590 down_read(&fc->killsb);
1591 err = -ENOENT;
1592 if (fc->sb)
1593 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1594 up_read(&fc->killsb);
1595 kfree(buf);
1596 return err;
1597
1598 err:
1599 kfree(buf);
1600 fuse_copy_finish(cs);
1601 return err;
1602 }
1603
1604 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1605 struct fuse_copy_state *cs)
1606 {
1607 struct fuse_notify_delete_out outarg;
1608 int err = -ENOMEM;
1609 char *buf;
1610 struct qstr name;
1611
1612 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1613 if (!buf)
1614 goto err;
1615
1616 err = -EINVAL;
1617 if (size < sizeof(outarg))
1618 goto err;
1619
1620 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1621 if (err)
1622 goto err;
1623
1624 err = -ENAMETOOLONG;
1625 if (outarg.namelen > FUSE_NAME_MAX)
1626 goto err;
1627
1628 err = -EINVAL;
1629 if (size != sizeof(outarg) + outarg.namelen + 1)
1630 goto err;
1631
1632 name.name = buf;
1633 name.len = outarg.namelen;
1634 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1635 if (err)
1636 goto err;
1637 fuse_copy_finish(cs);
1638 buf[outarg.namelen] = 0;
1639
1640 down_read(&fc->killsb);
1641 err = -ENOENT;
1642 if (fc->sb)
1643 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1644 outarg.child, &name);
1645 up_read(&fc->killsb);
1646 kfree(buf);
1647 return err;
1648
1649 err:
1650 kfree(buf);
1651 fuse_copy_finish(cs);
1652 return err;
1653 }
1654
1655 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1656 struct fuse_copy_state *cs)
1657 {
1658 struct fuse_notify_store_out outarg;
1659 struct inode *inode;
1660 struct address_space *mapping;
1661 u64 nodeid;
1662 int err;
1663 pgoff_t index;
1664 unsigned int offset;
1665 unsigned int num;
1666 loff_t file_size;
1667 loff_t end;
1668
1669 err = -EINVAL;
1670 if (size < sizeof(outarg))
1671 goto out_finish;
1672
1673 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1674 if (err)
1675 goto out_finish;
1676
1677 err = -EINVAL;
1678 if (size - sizeof(outarg) != outarg.size)
1679 goto out_finish;
1680
1681 nodeid = outarg.nodeid;
1682
1683 down_read(&fc->killsb);
1684
1685 err = -ENOENT;
1686 if (!fc->sb)
1687 goto out_up_killsb;
1688
1689 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1690 if (!inode)
1691 goto out_up_killsb;
1692
1693 mapping = inode->i_mapping;
1694 index = outarg.offset >> PAGE_SHIFT;
1695 offset = outarg.offset & ~PAGE_MASK;
1696 file_size = i_size_read(inode);
1697 end = outarg.offset + outarg.size;
1698 if (end > file_size) {
1699 file_size = end;
1700 fuse_write_update_size(inode, file_size);
1701 }
1702
1703 num = outarg.size;
1704 while (num) {
1705 struct page *page;
1706 unsigned int this_num;
1707
1708 err = -ENOMEM;
1709 page = find_or_create_page(mapping, index,
1710 mapping_gfp_mask(mapping));
1711 if (!page)
1712 goto out_iput;
1713
1714 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1715 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1716 if (!err && offset == 0 &&
1717 (this_num == PAGE_SIZE || file_size == end))
1718 SetPageUptodate(page);
1719 unlock_page(page);
1720 put_page(page);
1721
1722 if (err)
1723 goto out_iput;
1724
1725 num -= this_num;
1726 offset = 0;
1727 index++;
1728 }
1729
1730 err = 0;
1731
1732 out_iput:
1733 iput(inode);
1734 out_up_killsb:
1735 up_read(&fc->killsb);
1736 out_finish:
1737 fuse_copy_finish(cs);
1738 return err;
1739 }
1740
1741 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1742 {
1743 release_pages(req->pages, req->num_pages);
1744 }
1745
1746 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1747 struct fuse_notify_retrieve_out *outarg)
1748 {
1749 int err;
1750 struct address_space *mapping = inode->i_mapping;
1751 struct fuse_req *req;
1752 pgoff_t index;
1753 loff_t file_size;
1754 unsigned int num;
1755 unsigned int offset;
1756 size_t total_len = 0;
1757 unsigned int num_pages;
1758
1759 offset = outarg->offset & ~PAGE_MASK;
1760 file_size = i_size_read(inode);
1761
1762 num = min(outarg->size, fc->max_write);
1763 if (outarg->offset > file_size)
1764 num = 0;
1765 else if (outarg->offset + num > file_size)
1766 num = file_size - outarg->offset;
1767
1768 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1769 num_pages = min(num_pages, fc->max_pages);
1770
1771 req = fuse_get_req(fc, num_pages);
1772 if (IS_ERR(req))
1773 return PTR_ERR(req);
1774
1775 req->in.h.opcode = FUSE_NOTIFY_REPLY;
1776 req->in.h.nodeid = outarg->nodeid;
1777 req->in.numargs = 2;
1778 req->in.argpages = 1;
1779 req->end = fuse_retrieve_end;
1780
1781 index = outarg->offset >> PAGE_SHIFT;
1782
1783 while (num && req->num_pages < num_pages) {
1784 struct page *page;
1785 unsigned int this_num;
1786
1787 page = find_get_page(mapping, index);
1788 if (!page)
1789 break;
1790
1791 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1792 req->pages[req->num_pages] = page;
1793 req->page_descs[req->num_pages].offset = offset;
1794 req->page_descs[req->num_pages].length = this_num;
1795 req->num_pages++;
1796
1797 offset = 0;
1798 num -= this_num;
1799 total_len += this_num;
1800 index++;
1801 }
1802 req->misc.retrieve_in.offset = outarg->offset;
1803 req->misc.retrieve_in.size = total_len;
1804 req->in.args[0].size = sizeof(req->misc.retrieve_in);
1805 req->in.args[0].value = &req->misc.retrieve_in;
1806 req->in.args[1].size = total_len;
1807
1808 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1809 if (err) {
1810 fuse_retrieve_end(fc, req);
1811 fuse_put_request(fc, req);
1812 }
1813
1814 return err;
1815 }
1816
1817 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1818 struct fuse_copy_state *cs)
1819 {
1820 struct fuse_notify_retrieve_out outarg;
1821 struct inode *inode;
1822 int err;
1823
1824 err = -EINVAL;
1825 if (size != sizeof(outarg))
1826 goto copy_finish;
1827
1828 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1829 if (err)
1830 goto copy_finish;
1831
1832 fuse_copy_finish(cs);
1833
1834 down_read(&fc->killsb);
1835 err = -ENOENT;
1836 if (fc->sb) {
1837 u64 nodeid = outarg.nodeid;
1838
1839 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1840 if (inode) {
1841 err = fuse_retrieve(fc, inode, &outarg);
1842 iput(inode);
1843 }
1844 }
1845 up_read(&fc->killsb);
1846
1847 return err;
1848
1849 copy_finish:
1850 fuse_copy_finish(cs);
1851 return err;
1852 }
1853
1854 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1855 unsigned int size, struct fuse_copy_state *cs)
1856 {
1857 /* Don't try to move pages (yet) */
1858 cs->move_pages = 0;
1859
1860 switch (code) {
1861 case FUSE_NOTIFY_POLL:
1862 return fuse_notify_poll(fc, size, cs);
1863
1864 case FUSE_NOTIFY_INVAL_INODE:
1865 return fuse_notify_inval_inode(fc, size, cs);
1866
1867 case FUSE_NOTIFY_INVAL_ENTRY:
1868 return fuse_notify_inval_entry(fc, size, cs);
1869
1870 case FUSE_NOTIFY_STORE:
1871 return fuse_notify_store(fc, size, cs);
1872
1873 case FUSE_NOTIFY_RETRIEVE:
1874 return fuse_notify_retrieve(fc, size, cs);
1875
1876 case FUSE_NOTIFY_DELETE:
1877 return fuse_notify_delete(fc, size, cs);
1878
1879 default:
1880 fuse_copy_finish(cs);
1881 return -EINVAL;
1882 }
1883 }
1884
1885 /* Look up request on processing list by unique ID */
1886 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1887 {
1888 unsigned int hash = fuse_req_hash(unique);
1889 struct fuse_req *req;
1890
1891 list_for_each_entry(req, &fpq->processing[hash], list) {
1892 if (req->in.h.unique == unique)
1893 return req;
1894 }
1895 return NULL;
1896 }
1897
1898 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1899 unsigned nbytes)
1900 {
1901 unsigned reqsize = sizeof(struct fuse_out_header);
1902
1903 if (out->h.error)
1904 return nbytes != reqsize ? -EINVAL : 0;
1905
1906 reqsize += len_args(out->numargs, out->args);
1907
1908 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1909 return -EINVAL;
1910 else if (reqsize > nbytes) {
1911 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1912 unsigned diffsize = reqsize - nbytes;
1913 if (diffsize > lastarg->size)
1914 return -EINVAL;
1915 lastarg->size -= diffsize;
1916 }
1917 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1918 out->page_zeroing);
1919 }
1920
1921 /*
1922 * Write a single reply to a request. First the header is copied from
1923 * the write buffer. The request is then searched on the processing
1924 * list by the unique ID found in the header. If found, then remove
1925 * it from the list and copy the rest of the buffer to the request.
1926 * The request is finished by calling request_end()
1927 */
1928 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1929 struct fuse_copy_state *cs, size_t nbytes)
1930 {
1931 int err;
1932 struct fuse_conn *fc = fud->fc;
1933 struct fuse_pqueue *fpq = &fud->pq;
1934 struct fuse_req *req;
1935 struct fuse_out_header oh;
1936
1937 err = -EINVAL;
1938 if (nbytes < sizeof(struct fuse_out_header))
1939 goto out;
1940
1941 err = fuse_copy_one(cs, &oh, sizeof(oh));
1942 if (err)
1943 goto copy_finish;
1944
1945 err = -EINVAL;
1946 if (oh.len != nbytes)
1947 goto copy_finish;
1948
1949 /*
1950 * Zero oh.unique indicates unsolicited notification message
1951 * and error contains notification code.
1952 */
1953 if (!oh.unique) {
1954 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1955 goto out;
1956 }
1957
1958 err = -EINVAL;
1959 if (oh.error <= -1000 || oh.error > 0)
1960 goto copy_finish;
1961
1962 spin_lock(&fpq->lock);
1963 req = NULL;
1964 if (fpq->connected)
1965 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1966
1967 err = -ENOENT;
1968 if (!req) {
1969 spin_unlock(&fpq->lock);
1970 goto copy_finish;
1971 }
1972
1973 /* Is it an interrupt reply ID? */
1974 if (oh.unique & FUSE_INT_REQ_BIT) {
1975 __fuse_get_request(req);
1976 spin_unlock(&fpq->lock);
1977
1978 err = 0;
1979 if (nbytes != sizeof(struct fuse_out_header))
1980 err = -EINVAL;
1981 else if (oh.error == -ENOSYS)
1982 fc->no_interrupt = 1;
1983 else if (oh.error == -EAGAIN)
1984 err = queue_interrupt(&fc->iq, req);
1985
1986 fuse_put_request(fc, req);
1987
1988 goto copy_finish;
1989 }
1990
1991 clear_bit(FR_SENT, &req->flags);
1992 list_move(&req->list, &fpq->io);
1993 req->out.h = oh;
1994 set_bit(FR_LOCKED, &req->flags);
1995 spin_unlock(&fpq->lock);
1996 cs->req = req;
1997 if (!req->out.page_replace)
1998 cs->move_pages = 0;
1999
2000 err = copy_out_args(cs, &req->out, nbytes);
2001 fuse_copy_finish(cs);
2002
2003 spin_lock(&fpq->lock);
2004 clear_bit(FR_LOCKED, &req->flags);
2005 if (!fpq->connected)
2006 err = -ENOENT;
2007 else if (err)
2008 req->out.h.error = -EIO;
2009 if (!test_bit(FR_PRIVATE, &req->flags))
2010 list_del_init(&req->list);
2011 spin_unlock(&fpq->lock);
2012
2013 request_end(fc, req);
2014 out:
2015 return err ? err : nbytes;
2016
2017 copy_finish:
2018 fuse_copy_finish(cs);
2019 goto out;
2020 }
2021
2022 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
2023 {
2024 struct fuse_copy_state cs;
2025 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
2026
2027 if (!fud)
2028 return -EPERM;
2029
2030 if (!iter_is_iovec(from))
2031 return -EINVAL;
2032
2033 fuse_copy_init(&cs, 0, from);
2034
2035 return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
2036 }
2037
2038 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
2039 struct file *out, loff_t *ppos,
2040 size_t len, unsigned int flags)
2041 {
2042 unsigned nbuf;
2043 unsigned idx;
2044 struct pipe_buffer *bufs;
2045 struct fuse_copy_state cs;
2046 struct fuse_dev *fud;
2047 size_t rem;
2048 ssize_t ret;
2049
2050 fud = fuse_get_dev(out);
2051 if (!fud)
2052 return -EPERM;
2053
2054 pipe_lock(pipe);
2055
2056 bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer),
2057 GFP_KERNEL);
2058 if (!bufs) {
2059 pipe_unlock(pipe);
2060 return -ENOMEM;
2061 }
2062
2063 nbuf = 0;
2064 rem = 0;
2065 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
2066 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
2067
2068 ret = -EINVAL;
2069 if (rem < len)
2070 goto out_free;
2071
2072 rem = len;
2073 while (rem) {
2074 struct pipe_buffer *ibuf;
2075 struct pipe_buffer *obuf;
2076
2077 BUG_ON(nbuf >= pipe->buffers);
2078 BUG_ON(!pipe->nrbufs);
2079 ibuf = &pipe->bufs[pipe->curbuf];
2080 obuf = &bufs[nbuf];
2081
2082 if (rem >= ibuf->len) {
2083 *obuf = *ibuf;
2084 ibuf->ops = NULL;
2085 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2086 pipe->nrbufs--;
2087 } else {
2088 if (!pipe_buf_get(pipe, ibuf))
2089 goto out_free;
2090
2091 *obuf = *ibuf;
2092 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2093 obuf->len = rem;
2094 ibuf->offset += obuf->len;
2095 ibuf->len -= obuf->len;
2096 }
2097 nbuf++;
2098 rem -= obuf->len;
2099 }
2100 pipe_unlock(pipe);
2101
2102 fuse_copy_init(&cs, 0, NULL);
2103 cs.pipebufs = bufs;
2104 cs.nr_segs = nbuf;
2105 cs.pipe = pipe;
2106
2107 if (flags & SPLICE_F_MOVE)
2108 cs.move_pages = 1;
2109
2110 ret = fuse_dev_do_write(fud, &cs, len);
2111
2112 pipe_lock(pipe);
2113 out_free:
2114 for (idx = 0; idx < nbuf; idx++)
2115 pipe_buf_release(pipe, &bufs[idx]);
2116 pipe_unlock(pipe);
2117
2118 kvfree(bufs);
2119 return ret;
2120 }
2121
2122 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2123 {
2124 __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2125 struct fuse_iqueue *fiq;
2126 struct fuse_dev *fud = fuse_get_dev(file);
2127
2128 if (!fud)
2129 return EPOLLERR;
2130
2131 fiq = &fud->fc->iq;
2132 poll_wait(file, &fiq->waitq, wait);
2133
2134 spin_lock(&fiq->waitq.lock);
2135 if (!fiq->connected)
2136 mask = EPOLLERR;
2137 else if (request_pending(fiq))
2138 mask |= EPOLLIN | EPOLLRDNORM;
2139 spin_unlock(&fiq->waitq.lock);
2140
2141 return mask;
2142 }
2143
2144 /* Abort all requests on the given list (pending or processing) */
2145 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2146 {
2147 while (!list_empty(head)) {
2148 struct fuse_req *req;
2149 req = list_entry(head->next, struct fuse_req, list);
2150 req->out.h.error = -ECONNABORTED;
2151 clear_bit(FR_SENT, &req->flags);
2152 list_del_init(&req->list);
2153 request_end(fc, req);
2154 }
2155 }
2156
2157 static void end_polls(struct fuse_conn *fc)
2158 {
2159 struct rb_node *p;
2160
2161 p = rb_first(&fc->polled_files);
2162
2163 while (p) {
2164 struct fuse_file *ff;
2165 ff = rb_entry(p, struct fuse_file, polled_node);
2166 wake_up_interruptible_all(&ff->poll_wait);
2167
2168 p = rb_next(p);
2169 }
2170 }
2171
2172 /*
2173 * Abort all requests.
2174 *
2175 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2176 * filesystem.
2177 *
2178 * The same effect is usually achievable through killing the filesystem daemon
2179 * and all users of the filesystem. The exception is the combination of an
2180 * asynchronous request and the tricky deadlock (see
2181 * Documentation/filesystems/fuse.txt).
2182 *
2183 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2184 * requests, they should be finished off immediately. Locked requests will be
2185 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2186 * requests. It is possible that some request will finish before we can. This
2187 * is OK, the request will in that case be removed from the list before we touch
2188 * it.
2189 */
2190 void fuse_abort_conn(struct fuse_conn *fc)
2191 {
2192 struct fuse_iqueue *fiq = &fc->iq;
2193
2194 spin_lock(&fc->lock);
2195 if (fc->connected) {
2196 struct fuse_dev *fud;
2197 struct fuse_req *req, *next;
2198 LIST_HEAD(to_end);
2199 unsigned int i;
2200
2201 /* Background queuing checks fc->connected under bg_lock */
2202 spin_lock(&fc->bg_lock);
2203 fc->connected = 0;
2204 spin_unlock(&fc->bg_lock);
2205
2206 fuse_set_initialized(fc);
2207 list_for_each_entry(fud, &fc->devices, entry) {
2208 struct fuse_pqueue *fpq = &fud->pq;
2209
2210 spin_lock(&fpq->lock);
2211 fpq->connected = 0;
2212 list_for_each_entry_safe(req, next, &fpq->io, list) {
2213 req->out.h.error = -ECONNABORTED;
2214 spin_lock(&req->waitq.lock);
2215 set_bit(FR_ABORTED, &req->flags);
2216 if (!test_bit(FR_LOCKED, &req->flags)) {
2217 set_bit(FR_PRIVATE, &req->flags);
2218 __fuse_get_request(req);
2219 list_move(&req->list, &to_end);
2220 }
2221 spin_unlock(&req->waitq.lock);
2222 }
2223 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2224 list_splice_tail_init(&fpq->processing[i],
2225 &to_end);
2226 spin_unlock(&fpq->lock);
2227 }
2228 spin_lock(&fc->bg_lock);
2229 fc->blocked = 0;
2230 fc->max_background = UINT_MAX;
2231 flush_bg_queue(fc);
2232 spin_unlock(&fc->bg_lock);
2233
2234 spin_lock(&fiq->waitq.lock);
2235 fiq->connected = 0;
2236 list_for_each_entry(req, &fiq->pending, list)
2237 clear_bit(FR_PENDING, &req->flags);
2238 list_splice_tail_init(&fiq->pending, &to_end);
2239 while (forget_pending(fiq))
2240 kfree(dequeue_forget(fiq, 1, NULL));
2241 wake_up_all_locked(&fiq->waitq);
2242 spin_unlock(&fiq->waitq.lock);
2243 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2244 end_polls(fc);
2245 wake_up_all(&fc->blocked_waitq);
2246 spin_unlock(&fc->lock);
2247
2248 end_requests(fc, &to_end);
2249 } else {
2250 spin_unlock(&fc->lock);
2251 }
2252 }
2253 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2254
2255 void fuse_wait_aborted(struct fuse_conn *fc)
2256 {
2257 /* matches implicit memory barrier in fuse_drop_waiting() */
2258 smp_mb();
2259 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2260 }
2261
2262 int fuse_dev_release(struct inode *inode, struct file *file)
2263 {
2264 struct fuse_dev *fud = fuse_get_dev(file);
2265
2266 if (fud) {
2267 struct fuse_conn *fc = fud->fc;
2268 struct fuse_pqueue *fpq = &fud->pq;
2269 LIST_HEAD(to_end);
2270 unsigned int i;
2271
2272 spin_lock(&fpq->lock);
2273 WARN_ON(!list_empty(&fpq->io));
2274 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2275 list_splice_init(&fpq->processing[i], &to_end);
2276 spin_unlock(&fpq->lock);
2277
2278 end_requests(fc, &to_end);
2279
2280 /* Are we the last open device? */
2281 if (atomic_dec_and_test(&fc->dev_count)) {
2282 WARN_ON(fc->iq.fasync != NULL);
2283 fuse_abort_conn(fc);
2284 }
2285 fuse_dev_free(fud);
2286 }
2287 return 0;
2288 }
2289 EXPORT_SYMBOL_GPL(fuse_dev_release);
2290
2291 static int fuse_dev_fasync(int fd, struct file *file, int on)
2292 {
2293 struct fuse_dev *fud = fuse_get_dev(file);
2294
2295 if (!fud)
2296 return -EPERM;
2297
2298 /* No locking - fasync_helper does its own locking */
2299 return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2300 }
2301
2302 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2303 {
2304 struct fuse_dev *fud;
2305
2306 if (new->private_data)
2307 return -EINVAL;
2308
2309 fud = fuse_dev_alloc(fc);
2310 if (!fud)
2311 return -ENOMEM;
2312
2313 new->private_data = fud;
2314 atomic_inc(&fc->dev_count);
2315
2316 return 0;
2317 }
2318
2319 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2320 unsigned long arg)
2321 {
2322 int err = -ENOTTY;
2323
2324 if (cmd == FUSE_DEV_IOC_CLONE) {
2325 int oldfd;
2326
2327 err = -EFAULT;
2328 if (!get_user(oldfd, (__u32 __user *) arg)) {
2329 struct file *old = fget(oldfd);
2330
2331 err = -EINVAL;
2332 if (old) {
2333 struct fuse_dev *fud = NULL;
2334
2335 /*
2336 * Check against file->f_op because CUSE
2337 * uses the same ioctl handler.
2338 */
2339 if (old->f_op == file->f_op &&
2340 old->f_cred->user_ns == file->f_cred->user_ns)
2341 fud = fuse_get_dev(old);
2342
2343 if (fud) {
2344 mutex_lock(&fuse_mutex);
2345 err = fuse_device_clone(fud->fc, file);
2346 mutex_unlock(&fuse_mutex);
2347 }
2348 fput(old);
2349 }
2350 }
2351 }
2352 return err;
2353 }
2354
2355 const struct file_operations fuse_dev_operations = {
2356 .owner = THIS_MODULE,
2357 .open = fuse_dev_open,
2358 .llseek = no_llseek,
2359 .read_iter = fuse_dev_read,
2360 .splice_read = fuse_dev_splice_read,
2361 .write_iter = fuse_dev_write,
2362 .splice_write = fuse_dev_splice_write,
2363 .poll = fuse_dev_poll,
2364 .release = fuse_dev_release,
2365 .fasync = fuse_dev_fasync,
2366 .unlocked_ioctl = fuse_dev_ioctl,
2367 .compat_ioctl = fuse_dev_ioctl,
2368 };
2369 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2370
2371 static struct miscdevice fuse_miscdevice = {
2372 .minor = FUSE_MINOR,
2373 .name = "fuse",
2374 .fops = &fuse_dev_operations,
2375 };
2376
2377 int __init fuse_dev_init(void)
2378 {
2379 int err = -ENOMEM;
2380 fuse_req_cachep = kmem_cache_create("fuse_request",
2381 sizeof(struct fuse_req),
2382 0, 0, NULL);
2383 if (!fuse_req_cachep)
2384 goto out;
2385
2386 err = misc_register(&fuse_miscdevice);
2387 if (err)
2388 goto out_cache_clean;
2389
2390 return 0;
2391
2392 out_cache_clean:
2393 kmem_cache_destroy(fuse_req_cachep);
2394 out:
2395 return err;
2396 }
2397
2398 void fuse_dev_cleanup(void)
2399 {
2400 misc_deregister(&fuse_miscdevice);
2401 kmem_cache_destroy(fuse_req_cachep);
2402 }
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