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