Root/
1 | /* |
2 | FUSE: Filesystem in Userspace |
3 | Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> |
4 | |
5 | This program can be distributed under the terms of the GNU GPL. |
6 | See the file COPYING. |
7 | */ |
8 | |
9 | #include "fuse_i.h" |
10 | |
11 | #include <linux/init.h> |
12 | #include <linux/module.h> |
13 | #include <linux/poll.h> |
14 | #include <linux/uio.h> |
15 | #include <linux/miscdevice.h> |
16 | #include <linux/pagemap.h> |
17 | #include <linux/file.h> |
18 | #include <linux/slab.h> |
19 | |
20 | MODULE_ALIAS_MISCDEV(FUSE_MINOR); |
21 | |
22 | static struct kmem_cache *fuse_req_cachep; |
23 | |
24 | static struct fuse_conn *fuse_get_conn(struct file *file) |
25 | { |
26 | /* |
27 | * Lockless access is OK, because file->private data is set |
28 | * once during mount and is valid until the file is released. |
29 | */ |
30 | return file->private_data; |
31 | } |
32 | |
33 | static void fuse_request_init(struct fuse_req *req) |
34 | { |
35 | memset(req, 0, sizeof(*req)); |
36 | INIT_LIST_HEAD(&req->list); |
37 | INIT_LIST_HEAD(&req->intr_entry); |
38 | init_waitqueue_head(&req->waitq); |
39 | atomic_set(&req->count, 1); |
40 | } |
41 | |
42 | struct fuse_req *fuse_request_alloc(void) |
43 | { |
44 | struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL); |
45 | if (req) |
46 | fuse_request_init(req); |
47 | return req; |
48 | } |
49 | EXPORT_SYMBOL_GPL(fuse_request_alloc); |
50 | |
51 | struct fuse_req *fuse_request_alloc_nofs(void) |
52 | { |
53 | struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS); |
54 | if (req) |
55 | fuse_request_init(req); |
56 | return req; |
57 | } |
58 | |
59 | void fuse_request_free(struct fuse_req *req) |
60 | { |
61 | kmem_cache_free(fuse_req_cachep, req); |
62 | } |
63 | |
64 | static void block_sigs(sigset_t *oldset) |
65 | { |
66 | sigset_t mask; |
67 | |
68 | siginitsetinv(&mask, sigmask(SIGKILL)); |
69 | sigprocmask(SIG_BLOCK, &mask, oldset); |
70 | } |
71 | |
72 | static void restore_sigs(sigset_t *oldset) |
73 | { |
74 | sigprocmask(SIG_SETMASK, oldset, NULL); |
75 | } |
76 | |
77 | static void __fuse_get_request(struct fuse_req *req) |
78 | { |
79 | atomic_inc(&req->count); |
80 | } |
81 | |
82 | /* Must be called with > 1 refcount */ |
83 | static void __fuse_put_request(struct fuse_req *req) |
84 | { |
85 | BUG_ON(atomic_read(&req->count) < 2); |
86 | atomic_dec(&req->count); |
87 | } |
88 | |
89 | static void fuse_req_init_context(struct fuse_req *req) |
90 | { |
91 | req->in.h.uid = current_fsuid(); |
92 | req->in.h.gid = current_fsgid(); |
93 | req->in.h.pid = current->pid; |
94 | } |
95 | |
96 | struct fuse_req *fuse_get_req(struct fuse_conn *fc) |
97 | { |
98 | struct fuse_req *req; |
99 | sigset_t oldset; |
100 | int intr; |
101 | int err; |
102 | |
103 | atomic_inc(&fc->num_waiting); |
104 | block_sigs(&oldset); |
105 | intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked); |
106 | restore_sigs(&oldset); |
107 | err = -EINTR; |
108 | if (intr) |
109 | goto out; |
110 | |
111 | err = -ENOTCONN; |
112 | if (!fc->connected) |
113 | goto out; |
114 | |
115 | req = fuse_request_alloc(); |
116 | err = -ENOMEM; |
117 | if (!req) |
118 | goto out; |
119 | |
120 | fuse_req_init_context(req); |
121 | req->waiting = 1; |
122 | return req; |
123 | |
124 | out: |
125 | atomic_dec(&fc->num_waiting); |
126 | return ERR_PTR(err); |
127 | } |
128 | EXPORT_SYMBOL_GPL(fuse_get_req); |
129 | |
130 | /* |
131 | * Return request in fuse_file->reserved_req. However that may |
132 | * currently be in use. If that is the case, wait for it to become |
133 | * available. |
134 | */ |
135 | static struct fuse_req *get_reserved_req(struct fuse_conn *fc, |
136 | struct file *file) |
137 | { |
138 | struct fuse_req *req = NULL; |
139 | struct fuse_file *ff = file->private_data; |
140 | |
141 | do { |
142 | wait_event(fc->reserved_req_waitq, ff->reserved_req); |
143 | spin_lock(&fc->lock); |
144 | if (ff->reserved_req) { |
145 | req = ff->reserved_req; |
146 | ff->reserved_req = NULL; |
147 | get_file(file); |
148 | req->stolen_file = file; |
149 | } |
150 | spin_unlock(&fc->lock); |
151 | } while (!req); |
152 | |
153 | return req; |
154 | } |
155 | |
156 | /* |
157 | * Put stolen request back into fuse_file->reserved_req |
158 | */ |
159 | static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) |
160 | { |
161 | struct file *file = req->stolen_file; |
162 | struct fuse_file *ff = file->private_data; |
163 | |
164 | spin_lock(&fc->lock); |
165 | fuse_request_init(req); |
166 | BUG_ON(ff->reserved_req); |
167 | ff->reserved_req = req; |
168 | wake_up_all(&fc->reserved_req_waitq); |
169 | spin_unlock(&fc->lock); |
170 | fput(file); |
171 | } |
172 | |
173 | /* |
174 | * Gets a requests for a file operation, always succeeds |
175 | * |
176 | * This is used for sending the FLUSH request, which must get to |
177 | * userspace, due to POSIX locks which may need to be unlocked. |
178 | * |
179 | * If allocation fails due to OOM, use the reserved request in |
180 | * fuse_file. |
181 | * |
182 | * This is very unlikely to deadlock accidentally, since the |
183 | * filesystem should not have it's own file open. If deadlock is |
184 | * intentional, it can still be broken by "aborting" the filesystem. |
185 | */ |
186 | struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file) |
187 | { |
188 | struct fuse_req *req; |
189 | |
190 | atomic_inc(&fc->num_waiting); |
191 | wait_event(fc->blocked_waitq, !fc->blocked); |
192 | req = fuse_request_alloc(); |
193 | if (!req) |
194 | req = get_reserved_req(fc, file); |
195 | |
196 | fuse_req_init_context(req); |
197 | req->waiting = 1; |
198 | return req; |
199 | } |
200 | |
201 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) |
202 | { |
203 | if (atomic_dec_and_test(&req->count)) { |
204 | if (req->waiting) |
205 | atomic_dec(&fc->num_waiting); |
206 | |
207 | if (req->stolen_file) |
208 | put_reserved_req(fc, req); |
209 | else |
210 | fuse_request_free(req); |
211 | } |
212 | } |
213 | EXPORT_SYMBOL_GPL(fuse_put_request); |
214 | |
215 | static unsigned len_args(unsigned numargs, struct fuse_arg *args) |
216 | { |
217 | unsigned nbytes = 0; |
218 | unsigned i; |
219 | |
220 | for (i = 0; i < numargs; i++) |
221 | nbytes += args[i].size; |
222 | |
223 | return nbytes; |
224 | } |
225 | |
226 | static u64 fuse_get_unique(struct fuse_conn *fc) |
227 | { |
228 | fc->reqctr++; |
229 | /* zero is special */ |
230 | if (fc->reqctr == 0) |
231 | fc->reqctr = 1; |
232 | |
233 | return fc->reqctr; |
234 | } |
235 | |
236 | static void queue_request(struct fuse_conn *fc, struct fuse_req *req) |
237 | { |
238 | req->in.h.unique = fuse_get_unique(fc); |
239 | req->in.h.len = sizeof(struct fuse_in_header) + |
240 | len_args(req->in.numargs, (struct fuse_arg *) req->in.args); |
241 | list_add_tail(&req->list, &fc->pending); |
242 | req->state = FUSE_REQ_PENDING; |
243 | if (!req->waiting) { |
244 | req->waiting = 1; |
245 | atomic_inc(&fc->num_waiting); |
246 | } |
247 | wake_up(&fc->waitq); |
248 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
249 | } |
250 | |
251 | static void flush_bg_queue(struct fuse_conn *fc) |
252 | { |
253 | while (fc->active_background < fc->max_background && |
254 | !list_empty(&fc->bg_queue)) { |
255 | struct fuse_req *req; |
256 | |
257 | req = list_entry(fc->bg_queue.next, struct fuse_req, list); |
258 | list_del(&req->list); |
259 | fc->active_background++; |
260 | queue_request(fc, req); |
261 | } |
262 | } |
263 | |
264 | /* |
265 | * This function is called when a request is finished. Either a reply |
266 | * has arrived or it was aborted (and not yet sent) or some error |
267 | * occurred during communication with userspace, or the device file |
268 | * was closed. The requester thread is woken up (if still waiting), |
269 | * the 'end' callback is called if given, else the reference to the |
270 | * request is released |
271 | * |
272 | * Called with fc->lock, unlocks it |
273 | */ |
274 | static void request_end(struct fuse_conn *fc, struct fuse_req *req) |
275 | __releases(&fc->lock) |
276 | { |
277 | void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; |
278 | req->end = NULL; |
279 | list_del(&req->list); |
280 | list_del(&req->intr_entry); |
281 | req->state = FUSE_REQ_FINISHED; |
282 | if (req->background) { |
283 | if (fc->num_background == fc->max_background) { |
284 | fc->blocked = 0; |
285 | wake_up_all(&fc->blocked_waitq); |
286 | } |
287 | if (fc->num_background == fc->congestion_threshold && |
288 | fc->connected && fc->bdi_initialized) { |
289 | clear_bdi_congested(&fc->bdi, BLK_RW_SYNC); |
290 | clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC); |
291 | } |
292 | fc->num_background--; |
293 | fc->active_background--; |
294 | flush_bg_queue(fc); |
295 | } |
296 | spin_unlock(&fc->lock); |
297 | wake_up(&req->waitq); |
298 | if (end) |
299 | end(fc, req); |
300 | fuse_put_request(fc, req); |
301 | } |
302 | |
303 | static void wait_answer_interruptible(struct fuse_conn *fc, |
304 | struct fuse_req *req) |
305 | __releases(&fc->lock) |
306 | __acquires(&fc->lock) |
307 | { |
308 | if (signal_pending(current)) |
309 | return; |
310 | |
311 | spin_unlock(&fc->lock); |
312 | wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED); |
313 | spin_lock(&fc->lock); |
314 | } |
315 | |
316 | static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req) |
317 | { |
318 | list_add_tail(&req->intr_entry, &fc->interrupts); |
319 | wake_up(&fc->waitq); |
320 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
321 | } |
322 | |
323 | static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) |
324 | __releases(&fc->lock) |
325 | __acquires(&fc->lock) |
326 | { |
327 | if (!fc->no_interrupt) { |
328 | /* Any signal may interrupt this */ |
329 | wait_answer_interruptible(fc, req); |
330 | |
331 | if (req->aborted) |
332 | goto aborted; |
333 | if (req->state == FUSE_REQ_FINISHED) |
334 | return; |
335 | |
336 | req->interrupted = 1; |
337 | if (req->state == FUSE_REQ_SENT) |
338 | queue_interrupt(fc, req); |
339 | } |
340 | |
341 | if (!req->force) { |
342 | sigset_t oldset; |
343 | |
344 | /* Only fatal signals may interrupt this */ |
345 | block_sigs(&oldset); |
346 | wait_answer_interruptible(fc, req); |
347 | restore_sigs(&oldset); |
348 | |
349 | if (req->aborted) |
350 | goto aborted; |
351 | if (req->state == FUSE_REQ_FINISHED) |
352 | return; |
353 | |
354 | /* Request is not yet in userspace, bail out */ |
355 | if (req->state == FUSE_REQ_PENDING) { |
356 | list_del(&req->list); |
357 | __fuse_put_request(req); |
358 | req->out.h.error = -EINTR; |
359 | return; |
360 | } |
361 | } |
362 | |
363 | /* |
364 | * Either request is already in userspace, or it was forced. |
365 | * Wait it out. |
366 | */ |
367 | spin_unlock(&fc->lock); |
368 | wait_event(req->waitq, req->state == FUSE_REQ_FINISHED); |
369 | spin_lock(&fc->lock); |
370 | |
371 | if (!req->aborted) |
372 | return; |
373 | |
374 | aborted: |
375 | BUG_ON(req->state != FUSE_REQ_FINISHED); |
376 | if (req->locked) { |
377 | /* This is uninterruptible sleep, because data is |
378 | being copied to/from the buffers of req. During |
379 | locked state, there mustn't be any filesystem |
380 | operation (e.g. page fault), since that could lead |
381 | to deadlock */ |
382 | spin_unlock(&fc->lock); |
383 | wait_event(req->waitq, !req->locked); |
384 | spin_lock(&fc->lock); |
385 | } |
386 | } |
387 | |
388 | void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) |
389 | { |
390 | req->isreply = 1; |
391 | spin_lock(&fc->lock); |
392 | if (!fc->connected) |
393 | req->out.h.error = -ENOTCONN; |
394 | else if (fc->conn_error) |
395 | req->out.h.error = -ECONNREFUSED; |
396 | else { |
397 | queue_request(fc, req); |
398 | /* acquire extra reference, since request is still needed |
399 | after request_end() */ |
400 | __fuse_get_request(req); |
401 | |
402 | request_wait_answer(fc, req); |
403 | } |
404 | spin_unlock(&fc->lock); |
405 | } |
406 | EXPORT_SYMBOL_GPL(fuse_request_send); |
407 | |
408 | static void fuse_request_send_nowait_locked(struct fuse_conn *fc, |
409 | struct fuse_req *req) |
410 | { |
411 | req->background = 1; |
412 | fc->num_background++; |
413 | if (fc->num_background == fc->max_background) |
414 | fc->blocked = 1; |
415 | if (fc->num_background == fc->congestion_threshold && |
416 | fc->bdi_initialized) { |
417 | set_bdi_congested(&fc->bdi, BLK_RW_SYNC); |
418 | set_bdi_congested(&fc->bdi, BLK_RW_ASYNC); |
419 | } |
420 | list_add_tail(&req->list, &fc->bg_queue); |
421 | flush_bg_queue(fc); |
422 | } |
423 | |
424 | static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req) |
425 | { |
426 | spin_lock(&fc->lock); |
427 | if (fc->connected) { |
428 | fuse_request_send_nowait_locked(fc, req); |
429 | spin_unlock(&fc->lock); |
430 | } else { |
431 | req->out.h.error = -ENOTCONN; |
432 | request_end(fc, req); |
433 | } |
434 | } |
435 | |
436 | void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req) |
437 | { |
438 | req->isreply = 0; |
439 | fuse_request_send_nowait(fc, req); |
440 | } |
441 | |
442 | void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) |
443 | { |
444 | req->isreply = 1; |
445 | fuse_request_send_nowait(fc, req); |
446 | } |
447 | EXPORT_SYMBOL_GPL(fuse_request_send_background); |
448 | |
449 | /* |
450 | * Called under fc->lock |
451 | * |
452 | * fc->connected must have been checked previously |
453 | */ |
454 | void fuse_request_send_background_locked(struct fuse_conn *fc, |
455 | struct fuse_req *req) |
456 | { |
457 | req->isreply = 1; |
458 | fuse_request_send_nowait_locked(fc, req); |
459 | } |
460 | |
461 | /* |
462 | * Lock the request. Up to the next unlock_request() there mustn't be |
463 | * anything that could cause a page-fault. If the request was already |
464 | * aborted bail out. |
465 | */ |
466 | static int lock_request(struct fuse_conn *fc, struct fuse_req *req) |
467 | { |
468 | int err = 0; |
469 | if (req) { |
470 | spin_lock(&fc->lock); |
471 | if (req->aborted) |
472 | err = -ENOENT; |
473 | else |
474 | req->locked = 1; |
475 | spin_unlock(&fc->lock); |
476 | } |
477 | return err; |
478 | } |
479 | |
480 | /* |
481 | * Unlock request. If it was aborted during being locked, the |
482 | * requester thread is currently waiting for it to be unlocked, so |
483 | * wake it up. |
484 | */ |
485 | static void unlock_request(struct fuse_conn *fc, struct fuse_req *req) |
486 | { |
487 | if (req) { |
488 | spin_lock(&fc->lock); |
489 | req->locked = 0; |
490 | if (req->aborted) |
491 | wake_up(&req->waitq); |
492 | spin_unlock(&fc->lock); |
493 | } |
494 | } |
495 | |
496 | struct fuse_copy_state { |
497 | struct fuse_conn *fc; |
498 | int write; |
499 | struct fuse_req *req; |
500 | const struct iovec *iov; |
501 | unsigned long nr_segs; |
502 | unsigned long seglen; |
503 | unsigned long addr; |
504 | struct page *pg; |
505 | void *mapaddr; |
506 | void *buf; |
507 | unsigned len; |
508 | }; |
509 | |
510 | static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc, |
511 | int write, struct fuse_req *req, |
512 | const struct iovec *iov, unsigned long nr_segs) |
513 | { |
514 | memset(cs, 0, sizeof(*cs)); |
515 | cs->fc = fc; |
516 | cs->write = write; |
517 | cs->req = req; |
518 | cs->iov = iov; |
519 | cs->nr_segs = nr_segs; |
520 | } |
521 | |
522 | /* Unmap and put previous page of userspace buffer */ |
523 | static void fuse_copy_finish(struct fuse_copy_state *cs) |
524 | { |
525 | if (cs->mapaddr) { |
526 | kunmap_atomic(cs->mapaddr, KM_USER0); |
527 | if (cs->write) { |
528 | flush_dcache_page(cs->pg); |
529 | set_page_dirty_lock(cs->pg); |
530 | } |
531 | put_page(cs->pg); |
532 | cs->mapaddr = NULL; |
533 | } |
534 | } |
535 | |
536 | /* |
537 | * Get another pagefull of userspace buffer, and map it to kernel |
538 | * address space, and lock request |
539 | */ |
540 | static int fuse_copy_fill(struct fuse_copy_state *cs) |
541 | { |
542 | unsigned long offset; |
543 | int err; |
544 | |
545 | unlock_request(cs->fc, cs->req); |
546 | fuse_copy_finish(cs); |
547 | if (!cs->seglen) { |
548 | BUG_ON(!cs->nr_segs); |
549 | cs->seglen = cs->iov[0].iov_len; |
550 | cs->addr = (unsigned long) cs->iov[0].iov_base; |
551 | cs->iov++; |
552 | cs->nr_segs--; |
553 | } |
554 | down_read(¤t->mm->mmap_sem); |
555 | err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0, |
556 | &cs->pg, NULL); |
557 | up_read(¤t->mm->mmap_sem); |
558 | if (err < 0) |
559 | return err; |
560 | BUG_ON(err != 1); |
561 | offset = cs->addr % PAGE_SIZE; |
562 | cs->mapaddr = kmap_atomic(cs->pg, KM_USER0); |
563 | cs->buf = cs->mapaddr + offset; |
564 | cs->len = min(PAGE_SIZE - offset, cs->seglen); |
565 | cs->seglen -= cs->len; |
566 | cs->addr += cs->len; |
567 | |
568 | return lock_request(cs->fc, cs->req); |
569 | } |
570 | |
571 | /* Do as much copy to/from userspace buffer as we can */ |
572 | static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) |
573 | { |
574 | unsigned ncpy = min(*size, cs->len); |
575 | if (val) { |
576 | if (cs->write) |
577 | memcpy(cs->buf, *val, ncpy); |
578 | else |
579 | memcpy(*val, cs->buf, ncpy); |
580 | *val += ncpy; |
581 | } |
582 | *size -= ncpy; |
583 | cs->len -= ncpy; |
584 | cs->buf += ncpy; |
585 | return ncpy; |
586 | } |
587 | |
588 | /* |
589 | * Copy a page in the request to/from the userspace buffer. Must be |
590 | * done atomically |
591 | */ |
592 | static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page, |
593 | unsigned offset, unsigned count, int zeroing) |
594 | { |
595 | if (page && zeroing && count < PAGE_SIZE) { |
596 | void *mapaddr = kmap_atomic(page, KM_USER1); |
597 | memset(mapaddr, 0, PAGE_SIZE); |
598 | kunmap_atomic(mapaddr, KM_USER1); |
599 | } |
600 | while (count) { |
601 | if (!cs->len) { |
602 | int err = fuse_copy_fill(cs); |
603 | if (err) |
604 | return err; |
605 | } |
606 | if (page) { |
607 | void *mapaddr = kmap_atomic(page, KM_USER1); |
608 | void *buf = mapaddr + offset; |
609 | offset += fuse_copy_do(cs, &buf, &count); |
610 | kunmap_atomic(mapaddr, KM_USER1); |
611 | } else |
612 | offset += fuse_copy_do(cs, NULL, &count); |
613 | } |
614 | if (page && !cs->write) |
615 | flush_dcache_page(page); |
616 | return 0; |
617 | } |
618 | |
619 | /* Copy pages in the request to/from userspace buffer */ |
620 | static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, |
621 | int zeroing) |
622 | { |
623 | unsigned i; |
624 | struct fuse_req *req = cs->req; |
625 | unsigned offset = req->page_offset; |
626 | unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset); |
627 | |
628 | for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { |
629 | struct page *page = req->pages[i]; |
630 | int err = fuse_copy_page(cs, page, offset, count, zeroing); |
631 | if (err) |
632 | return err; |
633 | |
634 | nbytes -= count; |
635 | count = min(nbytes, (unsigned) PAGE_SIZE); |
636 | offset = 0; |
637 | } |
638 | return 0; |
639 | } |
640 | |
641 | /* Copy a single argument in the request to/from userspace buffer */ |
642 | static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) |
643 | { |
644 | while (size) { |
645 | if (!cs->len) { |
646 | int err = fuse_copy_fill(cs); |
647 | if (err) |
648 | return err; |
649 | } |
650 | fuse_copy_do(cs, &val, &size); |
651 | } |
652 | return 0; |
653 | } |
654 | |
655 | /* Copy request arguments to/from userspace buffer */ |
656 | static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, |
657 | unsigned argpages, struct fuse_arg *args, |
658 | int zeroing) |
659 | { |
660 | int err = 0; |
661 | unsigned i; |
662 | |
663 | for (i = 0; !err && i < numargs; i++) { |
664 | struct fuse_arg *arg = &args[i]; |
665 | if (i == numargs - 1 && argpages) |
666 | err = fuse_copy_pages(cs, arg->size, zeroing); |
667 | else |
668 | err = fuse_copy_one(cs, arg->value, arg->size); |
669 | } |
670 | return err; |
671 | } |
672 | |
673 | static int request_pending(struct fuse_conn *fc) |
674 | { |
675 | return !list_empty(&fc->pending) || !list_empty(&fc->interrupts); |
676 | } |
677 | |
678 | /* Wait until a request is available on the pending list */ |
679 | static void request_wait(struct fuse_conn *fc) |
680 | __releases(&fc->lock) |
681 | __acquires(&fc->lock) |
682 | { |
683 | DECLARE_WAITQUEUE(wait, current); |
684 | |
685 | add_wait_queue_exclusive(&fc->waitq, &wait); |
686 | while (fc->connected && !request_pending(fc)) { |
687 | set_current_state(TASK_INTERRUPTIBLE); |
688 | if (signal_pending(current)) |
689 | break; |
690 | |
691 | spin_unlock(&fc->lock); |
692 | schedule(); |
693 | spin_lock(&fc->lock); |
694 | } |
695 | set_current_state(TASK_RUNNING); |
696 | remove_wait_queue(&fc->waitq, &wait); |
697 | } |
698 | |
699 | /* |
700 | * Transfer an interrupt request to userspace |
701 | * |
702 | * Unlike other requests this is assembled on demand, without a need |
703 | * to allocate a separate fuse_req structure. |
704 | * |
705 | * Called with fc->lock held, releases it |
706 | */ |
707 | static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req, |
708 | const struct iovec *iov, unsigned long nr_segs) |
709 | __releases(&fc->lock) |
710 | { |
711 | struct fuse_copy_state cs; |
712 | struct fuse_in_header ih; |
713 | struct fuse_interrupt_in arg; |
714 | unsigned reqsize = sizeof(ih) + sizeof(arg); |
715 | int err; |
716 | |
717 | list_del_init(&req->intr_entry); |
718 | req->intr_unique = fuse_get_unique(fc); |
719 | memset(&ih, 0, sizeof(ih)); |
720 | memset(&arg, 0, sizeof(arg)); |
721 | ih.len = reqsize; |
722 | ih.opcode = FUSE_INTERRUPT; |
723 | ih.unique = req->intr_unique; |
724 | arg.unique = req->in.h.unique; |
725 | |
726 | spin_unlock(&fc->lock); |
727 | if (iov_length(iov, nr_segs) < reqsize) |
728 | return -EINVAL; |
729 | |
730 | fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs); |
731 | err = fuse_copy_one(&cs, &ih, sizeof(ih)); |
732 | if (!err) |
733 | err = fuse_copy_one(&cs, &arg, sizeof(arg)); |
734 | fuse_copy_finish(&cs); |
735 | |
736 | return err ? err : reqsize; |
737 | } |
738 | |
739 | /* |
740 | * Read a single request into the userspace filesystem's buffer. This |
741 | * function waits until a request is available, then removes it from |
742 | * the pending list and copies request data to userspace buffer. If |
743 | * no reply is needed (FORGET) or request has been aborted or there |
744 | * was an error during the copying then it's finished by calling |
745 | * request_end(). Otherwise add it to the processing list, and set |
746 | * the 'sent' flag. |
747 | */ |
748 | static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov, |
749 | unsigned long nr_segs, loff_t pos) |
750 | { |
751 | int err; |
752 | struct fuse_req *req; |
753 | struct fuse_in *in; |
754 | struct fuse_copy_state cs; |
755 | unsigned reqsize; |
756 | struct file *file = iocb->ki_filp; |
757 | struct fuse_conn *fc = fuse_get_conn(file); |
758 | if (!fc) |
759 | return -EPERM; |
760 | |
761 | restart: |
762 | spin_lock(&fc->lock); |
763 | err = -EAGAIN; |
764 | if ((file->f_flags & O_NONBLOCK) && fc->connected && |
765 | !request_pending(fc)) |
766 | goto err_unlock; |
767 | |
768 | request_wait(fc); |
769 | err = -ENODEV; |
770 | if (!fc->connected) |
771 | goto err_unlock; |
772 | err = -ERESTARTSYS; |
773 | if (!request_pending(fc)) |
774 | goto err_unlock; |
775 | |
776 | if (!list_empty(&fc->interrupts)) { |
777 | req = list_entry(fc->interrupts.next, struct fuse_req, |
778 | intr_entry); |
779 | return fuse_read_interrupt(fc, req, iov, nr_segs); |
780 | } |
781 | |
782 | req = list_entry(fc->pending.next, struct fuse_req, list); |
783 | req->state = FUSE_REQ_READING; |
784 | list_move(&req->list, &fc->io); |
785 | |
786 | in = &req->in; |
787 | reqsize = in->h.len; |
788 | /* If request is too large, reply with an error and restart the read */ |
789 | if (iov_length(iov, nr_segs) < reqsize) { |
790 | req->out.h.error = -EIO; |
791 | /* SETXATTR is special, since it may contain too large data */ |
792 | if (in->h.opcode == FUSE_SETXATTR) |
793 | req->out.h.error = -E2BIG; |
794 | request_end(fc, req); |
795 | goto restart; |
796 | } |
797 | spin_unlock(&fc->lock); |
798 | fuse_copy_init(&cs, fc, 1, req, iov, nr_segs); |
799 | err = fuse_copy_one(&cs, &in->h, sizeof(in->h)); |
800 | if (!err) |
801 | err = fuse_copy_args(&cs, in->numargs, in->argpages, |
802 | (struct fuse_arg *) in->args, 0); |
803 | fuse_copy_finish(&cs); |
804 | spin_lock(&fc->lock); |
805 | req->locked = 0; |
806 | if (req->aborted) { |
807 | request_end(fc, req); |
808 | return -ENODEV; |
809 | } |
810 | if (err) { |
811 | req->out.h.error = -EIO; |
812 | request_end(fc, req); |
813 | return err; |
814 | } |
815 | if (!req->isreply) |
816 | request_end(fc, req); |
817 | else { |
818 | req->state = FUSE_REQ_SENT; |
819 | list_move_tail(&req->list, &fc->processing); |
820 | if (req->interrupted) |
821 | queue_interrupt(fc, req); |
822 | spin_unlock(&fc->lock); |
823 | } |
824 | return reqsize; |
825 | |
826 | err_unlock: |
827 | spin_unlock(&fc->lock); |
828 | return err; |
829 | } |
830 | |
831 | static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, |
832 | struct fuse_copy_state *cs) |
833 | { |
834 | struct fuse_notify_poll_wakeup_out outarg; |
835 | int err = -EINVAL; |
836 | |
837 | if (size != sizeof(outarg)) |
838 | goto err; |
839 | |
840 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
841 | if (err) |
842 | goto err; |
843 | |
844 | fuse_copy_finish(cs); |
845 | return fuse_notify_poll_wakeup(fc, &outarg); |
846 | |
847 | err: |
848 | fuse_copy_finish(cs); |
849 | return err; |
850 | } |
851 | |
852 | static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, |
853 | struct fuse_copy_state *cs) |
854 | { |
855 | struct fuse_notify_inval_inode_out outarg; |
856 | int err = -EINVAL; |
857 | |
858 | if (size != sizeof(outarg)) |
859 | goto err; |
860 | |
861 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
862 | if (err) |
863 | goto err; |
864 | fuse_copy_finish(cs); |
865 | |
866 | down_read(&fc->killsb); |
867 | err = -ENOENT; |
868 | if (fc->sb) { |
869 | err = fuse_reverse_inval_inode(fc->sb, outarg.ino, |
870 | outarg.off, outarg.len); |
871 | } |
872 | up_read(&fc->killsb); |
873 | return err; |
874 | |
875 | err: |
876 | fuse_copy_finish(cs); |
877 | return err; |
878 | } |
879 | |
880 | static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, |
881 | struct fuse_copy_state *cs) |
882 | { |
883 | struct fuse_notify_inval_entry_out outarg; |
884 | int err = -ENOMEM; |
885 | char *buf; |
886 | struct qstr name; |
887 | |
888 | buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); |
889 | if (!buf) |
890 | goto err; |
891 | |
892 | err = -EINVAL; |
893 | if (size < sizeof(outarg)) |
894 | goto err; |
895 | |
896 | err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
897 | if (err) |
898 | goto err; |
899 | |
900 | err = -ENAMETOOLONG; |
901 | if (outarg.namelen > FUSE_NAME_MAX) |
902 | goto err; |
903 | |
904 | name.name = buf; |
905 | name.len = outarg.namelen; |
906 | err = fuse_copy_one(cs, buf, outarg.namelen + 1); |
907 | if (err) |
908 | goto err; |
909 | fuse_copy_finish(cs); |
910 | buf[outarg.namelen] = 0; |
911 | name.hash = full_name_hash(name.name, name.len); |
912 | |
913 | down_read(&fc->killsb); |
914 | err = -ENOENT; |
915 | if (fc->sb) |
916 | err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name); |
917 | up_read(&fc->killsb); |
918 | kfree(buf); |
919 | return err; |
920 | |
921 | err: |
922 | kfree(buf); |
923 | fuse_copy_finish(cs); |
924 | return err; |
925 | } |
926 | |
927 | static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, |
928 | unsigned int size, struct fuse_copy_state *cs) |
929 | { |
930 | switch (code) { |
931 | case FUSE_NOTIFY_POLL: |
932 | return fuse_notify_poll(fc, size, cs); |
933 | |
934 | case FUSE_NOTIFY_INVAL_INODE: |
935 | return fuse_notify_inval_inode(fc, size, cs); |
936 | |
937 | case FUSE_NOTIFY_INVAL_ENTRY: |
938 | return fuse_notify_inval_entry(fc, size, cs); |
939 | |
940 | default: |
941 | fuse_copy_finish(cs); |
942 | return -EINVAL; |
943 | } |
944 | } |
945 | |
946 | /* Look up request on processing list by unique ID */ |
947 | static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) |
948 | { |
949 | struct list_head *entry; |
950 | |
951 | list_for_each(entry, &fc->processing) { |
952 | struct fuse_req *req; |
953 | req = list_entry(entry, struct fuse_req, list); |
954 | if (req->in.h.unique == unique || req->intr_unique == unique) |
955 | return req; |
956 | } |
957 | return NULL; |
958 | } |
959 | |
960 | static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, |
961 | unsigned nbytes) |
962 | { |
963 | unsigned reqsize = sizeof(struct fuse_out_header); |
964 | |
965 | if (out->h.error) |
966 | return nbytes != reqsize ? -EINVAL : 0; |
967 | |
968 | reqsize += len_args(out->numargs, out->args); |
969 | |
970 | if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) |
971 | return -EINVAL; |
972 | else if (reqsize > nbytes) { |
973 | struct fuse_arg *lastarg = &out->args[out->numargs-1]; |
974 | unsigned diffsize = reqsize - nbytes; |
975 | if (diffsize > lastarg->size) |
976 | return -EINVAL; |
977 | lastarg->size -= diffsize; |
978 | } |
979 | return fuse_copy_args(cs, out->numargs, out->argpages, out->args, |
980 | out->page_zeroing); |
981 | } |
982 | |
983 | /* |
984 | * Write a single reply to a request. First the header is copied from |
985 | * the write buffer. The request is then searched on the processing |
986 | * list by the unique ID found in the header. If found, then remove |
987 | * it from the list and copy the rest of the buffer to the request. |
988 | * The request is finished by calling request_end() |
989 | */ |
990 | static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov, |
991 | unsigned long nr_segs, loff_t pos) |
992 | { |
993 | int err; |
994 | size_t nbytes = iov_length(iov, nr_segs); |
995 | struct fuse_req *req; |
996 | struct fuse_out_header oh; |
997 | struct fuse_copy_state cs; |
998 | struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp); |
999 | if (!fc) |
1000 | return -EPERM; |
1001 | |
1002 | fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs); |
1003 | if (nbytes < sizeof(struct fuse_out_header)) |
1004 | return -EINVAL; |
1005 | |
1006 | err = fuse_copy_one(&cs, &oh, sizeof(oh)); |
1007 | if (err) |
1008 | goto err_finish; |
1009 | |
1010 | err = -EINVAL; |
1011 | if (oh.len != nbytes) |
1012 | goto err_finish; |
1013 | |
1014 | /* |
1015 | * Zero oh.unique indicates unsolicited notification message |
1016 | * and error contains notification code. |
1017 | */ |
1018 | if (!oh.unique) { |
1019 | err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), &cs); |
1020 | return err ? err : nbytes; |
1021 | } |
1022 | |
1023 | err = -EINVAL; |
1024 | if (oh.error <= -1000 || oh.error > 0) |
1025 | goto err_finish; |
1026 | |
1027 | spin_lock(&fc->lock); |
1028 | err = -ENOENT; |
1029 | if (!fc->connected) |
1030 | goto err_unlock; |
1031 | |
1032 | req = request_find(fc, oh.unique); |
1033 | if (!req) |
1034 | goto err_unlock; |
1035 | |
1036 | if (req->aborted) { |
1037 | spin_unlock(&fc->lock); |
1038 | fuse_copy_finish(&cs); |
1039 | spin_lock(&fc->lock); |
1040 | request_end(fc, req); |
1041 | return -ENOENT; |
1042 | } |
1043 | /* Is it an interrupt reply? */ |
1044 | if (req->intr_unique == oh.unique) { |
1045 | err = -EINVAL; |
1046 | if (nbytes != sizeof(struct fuse_out_header)) |
1047 | goto err_unlock; |
1048 | |
1049 | if (oh.error == -ENOSYS) |
1050 | fc->no_interrupt = 1; |
1051 | else if (oh.error == -EAGAIN) |
1052 | queue_interrupt(fc, req); |
1053 | |
1054 | spin_unlock(&fc->lock); |
1055 | fuse_copy_finish(&cs); |
1056 | return nbytes; |
1057 | } |
1058 | |
1059 | req->state = FUSE_REQ_WRITING; |
1060 | list_move(&req->list, &fc->io); |
1061 | req->out.h = oh; |
1062 | req->locked = 1; |
1063 | cs.req = req; |
1064 | spin_unlock(&fc->lock); |
1065 | |
1066 | err = copy_out_args(&cs, &req->out, nbytes); |
1067 | fuse_copy_finish(&cs); |
1068 | |
1069 | spin_lock(&fc->lock); |
1070 | req->locked = 0; |
1071 | if (!err) { |
1072 | if (req->aborted) |
1073 | err = -ENOENT; |
1074 | } else if (!req->aborted) |
1075 | req->out.h.error = -EIO; |
1076 | request_end(fc, req); |
1077 | |
1078 | return err ? err : nbytes; |
1079 | |
1080 | err_unlock: |
1081 | spin_unlock(&fc->lock); |
1082 | err_finish: |
1083 | fuse_copy_finish(&cs); |
1084 | return err; |
1085 | } |
1086 | |
1087 | static unsigned fuse_dev_poll(struct file *file, poll_table *wait) |
1088 | { |
1089 | unsigned mask = POLLOUT | POLLWRNORM; |
1090 | struct fuse_conn *fc = fuse_get_conn(file); |
1091 | if (!fc) |
1092 | return POLLERR; |
1093 | |
1094 | poll_wait(file, &fc->waitq, wait); |
1095 | |
1096 | spin_lock(&fc->lock); |
1097 | if (!fc->connected) |
1098 | mask = POLLERR; |
1099 | else if (request_pending(fc)) |
1100 | mask |= POLLIN | POLLRDNORM; |
1101 | spin_unlock(&fc->lock); |
1102 | |
1103 | return mask; |
1104 | } |
1105 | |
1106 | /* |
1107 | * Abort all requests on the given list (pending or processing) |
1108 | * |
1109 | * This function releases and reacquires fc->lock |
1110 | */ |
1111 | static void end_requests(struct fuse_conn *fc, struct list_head *head) |
1112 | __releases(&fc->lock) |
1113 | __acquires(&fc->lock) |
1114 | { |
1115 | while (!list_empty(head)) { |
1116 | struct fuse_req *req; |
1117 | req = list_entry(head->next, struct fuse_req, list); |
1118 | req->out.h.error = -ECONNABORTED; |
1119 | request_end(fc, req); |
1120 | spin_lock(&fc->lock); |
1121 | } |
1122 | } |
1123 | |
1124 | /* |
1125 | * Abort requests under I/O |
1126 | * |
1127 | * The requests are set to aborted and finished, and the request |
1128 | * waiter is woken up. This will make request_wait_answer() wait |
1129 | * until the request is unlocked and then return. |
1130 | * |
1131 | * If the request is asynchronous, then the end function needs to be |
1132 | * called after waiting for the request to be unlocked (if it was |
1133 | * locked). |
1134 | */ |
1135 | static void end_io_requests(struct fuse_conn *fc) |
1136 | __releases(&fc->lock) |
1137 | __acquires(&fc->lock) |
1138 | { |
1139 | while (!list_empty(&fc->io)) { |
1140 | struct fuse_req *req = |
1141 | list_entry(fc->io.next, struct fuse_req, list); |
1142 | void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; |
1143 | |
1144 | req->aborted = 1; |
1145 | req->out.h.error = -ECONNABORTED; |
1146 | req->state = FUSE_REQ_FINISHED; |
1147 | list_del_init(&req->list); |
1148 | wake_up(&req->waitq); |
1149 | if (end) { |
1150 | req->end = NULL; |
1151 | __fuse_get_request(req); |
1152 | spin_unlock(&fc->lock); |
1153 | wait_event(req->waitq, !req->locked); |
1154 | end(fc, req); |
1155 | fuse_put_request(fc, req); |
1156 | spin_lock(&fc->lock); |
1157 | } |
1158 | } |
1159 | } |
1160 | |
1161 | /* |
1162 | * Abort all requests. |
1163 | * |
1164 | * Emergency exit in case of a malicious or accidental deadlock, or |
1165 | * just a hung filesystem. |
1166 | * |
1167 | * The same effect is usually achievable through killing the |
1168 | * filesystem daemon and all users of the filesystem. The exception |
1169 | * is the combination of an asynchronous request and the tricky |
1170 | * deadlock (see Documentation/filesystems/fuse.txt). |
1171 | * |
1172 | * During the aborting, progression of requests from the pending and |
1173 | * processing lists onto the io list, and progression of new requests |
1174 | * onto the pending list is prevented by req->connected being false. |
1175 | * |
1176 | * Progression of requests under I/O to the processing list is |
1177 | * prevented by the req->aborted flag being true for these requests. |
1178 | * For this reason requests on the io list must be aborted first. |
1179 | */ |
1180 | void fuse_abort_conn(struct fuse_conn *fc) |
1181 | { |
1182 | spin_lock(&fc->lock); |
1183 | if (fc->connected) { |
1184 | fc->connected = 0; |
1185 | fc->blocked = 0; |
1186 | end_io_requests(fc); |
1187 | end_requests(fc, &fc->pending); |
1188 | end_requests(fc, &fc->processing); |
1189 | wake_up_all(&fc->waitq); |
1190 | wake_up_all(&fc->blocked_waitq); |
1191 | kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
1192 | } |
1193 | spin_unlock(&fc->lock); |
1194 | } |
1195 | EXPORT_SYMBOL_GPL(fuse_abort_conn); |
1196 | |
1197 | int fuse_dev_release(struct inode *inode, struct file *file) |
1198 | { |
1199 | struct fuse_conn *fc = fuse_get_conn(file); |
1200 | if (fc) { |
1201 | spin_lock(&fc->lock); |
1202 | fc->connected = 0; |
1203 | end_requests(fc, &fc->pending); |
1204 | end_requests(fc, &fc->processing); |
1205 | spin_unlock(&fc->lock); |
1206 | fuse_conn_put(fc); |
1207 | } |
1208 | |
1209 | return 0; |
1210 | } |
1211 | EXPORT_SYMBOL_GPL(fuse_dev_release); |
1212 | |
1213 | static int fuse_dev_fasync(int fd, struct file *file, int on) |
1214 | { |
1215 | struct fuse_conn *fc = fuse_get_conn(file); |
1216 | if (!fc) |
1217 | return -EPERM; |
1218 | |
1219 | /* No locking - fasync_helper does its own locking */ |
1220 | return fasync_helper(fd, file, on, &fc->fasync); |
1221 | } |
1222 | |
1223 | const struct file_operations fuse_dev_operations = { |
1224 | .owner = THIS_MODULE, |
1225 | .llseek = no_llseek, |
1226 | .read = do_sync_read, |
1227 | .aio_read = fuse_dev_read, |
1228 | .write = do_sync_write, |
1229 | .aio_write = fuse_dev_write, |
1230 | .poll = fuse_dev_poll, |
1231 | .release = fuse_dev_release, |
1232 | .fasync = fuse_dev_fasync, |
1233 | }; |
1234 | EXPORT_SYMBOL_GPL(fuse_dev_operations); |
1235 | |
1236 | static struct miscdevice fuse_miscdevice = { |
1237 | .minor = FUSE_MINOR, |
1238 | .name = "fuse", |
1239 | .fops = &fuse_dev_operations, |
1240 | }; |
1241 | |
1242 | int __init fuse_dev_init(void) |
1243 | { |
1244 | int err = -ENOMEM; |
1245 | fuse_req_cachep = kmem_cache_create("fuse_request", |
1246 | sizeof(struct fuse_req), |
1247 | 0, 0, NULL); |
1248 | if (!fuse_req_cachep) |
1249 | goto out; |
1250 | |
1251 | err = misc_register(&fuse_miscdevice); |
1252 | if (err) |
1253 | goto out_cache_clean; |
1254 | |
1255 | return 0; |
1256 | |
1257 | out_cache_clean: |
1258 | kmem_cache_destroy(fuse_req_cachep); |
1259 | out: |
1260 | return err; |
1261 | } |
1262 | |
1263 | void fuse_dev_cleanup(void) |
1264 | { |
1265 | misc_deregister(&fuse_miscdevice); |
1266 | kmem_cache_destroy(fuse_req_cachep); |
1267 | } |
1268 |
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jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9