x86, PAT: Remove page granularity tracking for vm_insert_pfn maps
[linux-2.6/mini2440.git] / fs / fuse / dev.c
blobba76b68c52ffe2d127178d71ca5b5ab2ecc6a353
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
9 #include "fuse_i.h"
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>
20 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
22 static struct kmem_cache *fuse_req_cachep;
24 static struct fuse_conn *fuse_get_conn(struct file *file)
27 * Lockless access is OK, because file->private data is set
28 * once during mount and is valid until the file is released.
30 return file->private_data;
33 static void fuse_request_init(struct fuse_req *req)
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);
42 struct fuse_req *fuse_request_alloc(void)
44 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
45 if (req)
46 fuse_request_init(req);
47 return req;
50 struct fuse_req *fuse_request_alloc_nofs(void)
52 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
53 if (req)
54 fuse_request_init(req);
55 return req;
58 void fuse_request_free(struct fuse_req *req)
60 kmem_cache_free(fuse_req_cachep, req);
63 static void block_sigs(sigset_t *oldset)
65 sigset_t mask;
67 siginitsetinv(&mask, sigmask(SIGKILL));
68 sigprocmask(SIG_BLOCK, &mask, oldset);
71 static void restore_sigs(sigset_t *oldset)
73 sigprocmask(SIG_SETMASK, oldset, NULL);
76 static void __fuse_get_request(struct fuse_req *req)
78 atomic_inc(&req->count);
81 /* Must be called with > 1 refcount */
82 static void __fuse_put_request(struct fuse_req *req)
84 BUG_ON(atomic_read(&req->count) < 2);
85 atomic_dec(&req->count);
88 static void fuse_req_init_context(struct fuse_req *req)
90 req->in.h.uid = current_fsuid();
91 req->in.h.gid = current_fsgid();
92 req->in.h.pid = current->pid;
95 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
97 struct fuse_req *req;
98 sigset_t oldset;
99 int intr;
100 int err;
102 atomic_inc(&fc->num_waiting);
103 block_sigs(&oldset);
104 intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
105 restore_sigs(&oldset);
106 err = -EINTR;
107 if (intr)
108 goto out;
110 err = -ENOTCONN;
111 if (!fc->connected)
112 goto out;
114 req = fuse_request_alloc();
115 err = -ENOMEM;
116 if (!req)
117 goto out;
119 fuse_req_init_context(req);
120 req->waiting = 1;
121 return req;
123 out:
124 atomic_dec(&fc->num_waiting);
125 return ERR_PTR(err);
129 * Return request in fuse_file->reserved_req. However that may
130 * currently be in use. If that is the case, wait for it to become
131 * available.
133 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
134 struct file *file)
136 struct fuse_req *req = NULL;
137 struct fuse_file *ff = file->private_data;
139 do {
140 wait_event(fc->reserved_req_waitq, ff->reserved_req);
141 spin_lock(&fc->lock);
142 if (ff->reserved_req) {
143 req = ff->reserved_req;
144 ff->reserved_req = NULL;
145 get_file(file);
146 req->stolen_file = file;
148 spin_unlock(&fc->lock);
149 } while (!req);
151 return req;
155 * Put stolen request back into fuse_file->reserved_req
157 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
159 struct file *file = req->stolen_file;
160 struct fuse_file *ff = file->private_data;
162 spin_lock(&fc->lock);
163 fuse_request_init(req);
164 BUG_ON(ff->reserved_req);
165 ff->reserved_req = req;
166 wake_up_all(&fc->reserved_req_waitq);
167 spin_unlock(&fc->lock);
168 fput(file);
172 * Gets a requests for a file operation, always succeeds
174 * This is used for sending the FLUSH request, which must get to
175 * userspace, due to POSIX locks which may need to be unlocked.
177 * If allocation fails due to OOM, use the reserved request in
178 * fuse_file.
180 * This is very unlikely to deadlock accidentally, since the
181 * filesystem should not have it's own file open. If deadlock is
182 * intentional, it can still be broken by "aborting" the filesystem.
184 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
186 struct fuse_req *req;
188 atomic_inc(&fc->num_waiting);
189 wait_event(fc->blocked_waitq, !fc->blocked);
190 req = fuse_request_alloc();
191 if (!req)
192 req = get_reserved_req(fc, file);
194 fuse_req_init_context(req);
195 req->waiting = 1;
196 return req;
199 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
201 if (atomic_dec_and_test(&req->count)) {
202 if (req->waiting)
203 atomic_dec(&fc->num_waiting);
205 if (req->stolen_file)
206 put_reserved_req(fc, req);
207 else
208 fuse_request_free(req);
212 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
214 unsigned nbytes = 0;
215 unsigned i;
217 for (i = 0; i < numargs; i++)
218 nbytes += args[i].size;
220 return nbytes;
223 static u64 fuse_get_unique(struct fuse_conn *fc)
225 fc->reqctr++;
226 /* zero is special */
227 if (fc->reqctr == 0)
228 fc->reqctr = 1;
230 return fc->reqctr;
233 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
235 req->in.h.unique = fuse_get_unique(fc);
236 req->in.h.len = sizeof(struct fuse_in_header) +
237 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
238 list_add_tail(&req->list, &fc->pending);
239 req->state = FUSE_REQ_PENDING;
240 if (!req->waiting) {
241 req->waiting = 1;
242 atomic_inc(&fc->num_waiting);
244 wake_up(&fc->waitq);
245 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
248 static void flush_bg_queue(struct fuse_conn *fc)
250 while (fc->active_background < FUSE_MAX_BACKGROUND &&
251 !list_empty(&fc->bg_queue)) {
252 struct fuse_req *req;
254 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
255 list_del(&req->list);
256 fc->active_background++;
257 queue_request(fc, req);
262 * This function is called when a request is finished. Either a reply
263 * has arrived or it was aborted (and not yet sent) or some error
264 * occurred during communication with userspace, or the device file
265 * was closed. The requester thread is woken up (if still waiting),
266 * the 'end' callback is called if given, else the reference to the
267 * request is released
269 * Called with fc->lock, unlocks it
271 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
272 __releases(&fc->lock)
274 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
275 req->end = NULL;
276 list_del(&req->list);
277 list_del(&req->intr_entry);
278 req->state = FUSE_REQ_FINISHED;
279 if (req->background) {
280 if (fc->num_background == FUSE_MAX_BACKGROUND) {
281 fc->blocked = 0;
282 wake_up_all(&fc->blocked_waitq);
284 if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
285 fc->connected) {
286 clear_bdi_congested(&fc->bdi, READ);
287 clear_bdi_congested(&fc->bdi, WRITE);
289 fc->num_background--;
290 fc->active_background--;
291 flush_bg_queue(fc);
293 spin_unlock(&fc->lock);
294 wake_up(&req->waitq);
295 if (end)
296 end(fc, req);
297 fuse_put_request(fc, req);
300 static void wait_answer_interruptible(struct fuse_conn *fc,
301 struct fuse_req *req)
302 __releases(&fc->lock)
303 __acquires(&fc->lock)
305 if (signal_pending(current))
306 return;
308 spin_unlock(&fc->lock);
309 wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
310 spin_lock(&fc->lock);
313 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
315 list_add_tail(&req->intr_entry, &fc->interrupts);
316 wake_up(&fc->waitq);
317 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
320 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
321 __releases(&fc->lock)
322 __acquires(&fc->lock)
324 if (!fc->no_interrupt) {
325 /* Any signal may interrupt this */
326 wait_answer_interruptible(fc, req);
328 if (req->aborted)
329 goto aborted;
330 if (req->state == FUSE_REQ_FINISHED)
331 return;
333 req->interrupted = 1;
334 if (req->state == FUSE_REQ_SENT)
335 queue_interrupt(fc, req);
338 if (!req->force) {
339 sigset_t oldset;
341 /* Only fatal signals may interrupt this */
342 block_sigs(&oldset);
343 wait_answer_interruptible(fc, req);
344 restore_sigs(&oldset);
346 if (req->aborted)
347 goto aborted;
348 if (req->state == FUSE_REQ_FINISHED)
349 return;
351 /* Request is not yet in userspace, bail out */
352 if (req->state == FUSE_REQ_PENDING) {
353 list_del(&req->list);
354 __fuse_put_request(req);
355 req->out.h.error = -EINTR;
356 return;
361 * Either request is already in userspace, or it was forced.
362 * Wait it out.
364 spin_unlock(&fc->lock);
365 wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
366 spin_lock(&fc->lock);
368 if (!req->aborted)
369 return;
371 aborted:
372 BUG_ON(req->state != FUSE_REQ_FINISHED);
373 if (req->locked) {
374 /* This is uninterruptible sleep, because data is
375 being copied to/from the buffers of req. During
376 locked state, there mustn't be any filesystem
377 operation (e.g. page fault), since that could lead
378 to deadlock */
379 spin_unlock(&fc->lock);
380 wait_event(req->waitq, !req->locked);
381 spin_lock(&fc->lock);
385 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
387 req->isreply = 1;
388 spin_lock(&fc->lock);
389 if (!fc->connected)
390 req->out.h.error = -ENOTCONN;
391 else if (fc->conn_error)
392 req->out.h.error = -ECONNREFUSED;
393 else {
394 queue_request(fc, req);
395 /* acquire extra reference, since request is still needed
396 after request_end() */
397 __fuse_get_request(req);
399 request_wait_answer(fc, req);
401 spin_unlock(&fc->lock);
404 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
405 struct fuse_req *req)
407 req->background = 1;
408 fc->num_background++;
409 if (fc->num_background == FUSE_MAX_BACKGROUND)
410 fc->blocked = 1;
411 if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
412 set_bdi_congested(&fc->bdi, READ);
413 set_bdi_congested(&fc->bdi, WRITE);
415 list_add_tail(&req->list, &fc->bg_queue);
416 flush_bg_queue(fc);
419 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
421 spin_lock(&fc->lock);
422 if (fc->connected) {
423 fuse_request_send_nowait_locked(fc, req);
424 spin_unlock(&fc->lock);
425 } else {
426 req->out.h.error = -ENOTCONN;
427 request_end(fc, req);
431 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
433 req->isreply = 0;
434 fuse_request_send_nowait(fc, req);
437 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
439 req->isreply = 1;
440 fuse_request_send_nowait(fc, req);
444 * Called under fc->lock
446 * fc->connected must have been checked previously
448 void fuse_request_send_background_locked(struct fuse_conn *fc,
449 struct fuse_req *req)
451 req->isreply = 1;
452 fuse_request_send_nowait_locked(fc, req);
456 * Lock the request. Up to the next unlock_request() there mustn't be
457 * anything that could cause a page-fault. If the request was already
458 * aborted bail out.
460 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
462 int err = 0;
463 if (req) {
464 spin_lock(&fc->lock);
465 if (req->aborted)
466 err = -ENOENT;
467 else
468 req->locked = 1;
469 spin_unlock(&fc->lock);
471 return err;
475 * Unlock request. If it was aborted during being locked, the
476 * requester thread is currently waiting for it to be unlocked, so
477 * wake it up.
479 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
481 if (req) {
482 spin_lock(&fc->lock);
483 req->locked = 0;
484 if (req->aborted)
485 wake_up(&req->waitq);
486 spin_unlock(&fc->lock);
490 struct fuse_copy_state {
491 struct fuse_conn *fc;
492 int write;
493 struct fuse_req *req;
494 const struct iovec *iov;
495 unsigned long nr_segs;
496 unsigned long seglen;
497 unsigned long addr;
498 struct page *pg;
499 void *mapaddr;
500 void *buf;
501 unsigned len;
504 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
505 int write, struct fuse_req *req,
506 const struct iovec *iov, unsigned long nr_segs)
508 memset(cs, 0, sizeof(*cs));
509 cs->fc = fc;
510 cs->write = write;
511 cs->req = req;
512 cs->iov = iov;
513 cs->nr_segs = nr_segs;
516 /* Unmap and put previous page of userspace buffer */
517 static void fuse_copy_finish(struct fuse_copy_state *cs)
519 if (cs->mapaddr) {
520 kunmap_atomic(cs->mapaddr, KM_USER0);
521 if (cs->write) {
522 flush_dcache_page(cs->pg);
523 set_page_dirty_lock(cs->pg);
525 put_page(cs->pg);
526 cs->mapaddr = NULL;
531 * Get another pagefull of userspace buffer, and map it to kernel
532 * address space, and lock request
534 static int fuse_copy_fill(struct fuse_copy_state *cs)
536 unsigned long offset;
537 int err;
539 unlock_request(cs->fc, cs->req);
540 fuse_copy_finish(cs);
541 if (!cs->seglen) {
542 BUG_ON(!cs->nr_segs);
543 cs->seglen = cs->iov[0].iov_len;
544 cs->addr = (unsigned long) cs->iov[0].iov_base;
545 cs->iov++;
546 cs->nr_segs--;
548 down_read(&current->mm->mmap_sem);
549 err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0,
550 &cs->pg, NULL);
551 up_read(&current->mm->mmap_sem);
552 if (err < 0)
553 return err;
554 BUG_ON(err != 1);
555 offset = cs->addr % PAGE_SIZE;
556 cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
557 cs->buf = cs->mapaddr + offset;
558 cs->len = min(PAGE_SIZE - offset, cs->seglen);
559 cs->seglen -= cs->len;
560 cs->addr += cs->len;
562 return lock_request(cs->fc, cs->req);
565 /* Do as much copy to/from userspace buffer as we can */
566 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
568 unsigned ncpy = min(*size, cs->len);
569 if (val) {
570 if (cs->write)
571 memcpy(cs->buf, *val, ncpy);
572 else
573 memcpy(*val, cs->buf, ncpy);
574 *val += ncpy;
576 *size -= ncpy;
577 cs->len -= ncpy;
578 cs->buf += ncpy;
579 return ncpy;
583 * Copy a page in the request to/from the userspace buffer. Must be
584 * done atomically
586 static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page,
587 unsigned offset, unsigned count, int zeroing)
589 if (page && zeroing && count < PAGE_SIZE) {
590 void *mapaddr = kmap_atomic(page, KM_USER1);
591 memset(mapaddr, 0, PAGE_SIZE);
592 kunmap_atomic(mapaddr, KM_USER1);
594 while (count) {
595 if (!cs->len) {
596 int err = fuse_copy_fill(cs);
597 if (err)
598 return err;
600 if (page) {
601 void *mapaddr = kmap_atomic(page, KM_USER1);
602 void *buf = mapaddr + offset;
603 offset += fuse_copy_do(cs, &buf, &count);
604 kunmap_atomic(mapaddr, KM_USER1);
605 } else
606 offset += fuse_copy_do(cs, NULL, &count);
608 if (page && !cs->write)
609 flush_dcache_page(page);
610 return 0;
613 /* Copy pages in the request to/from userspace buffer */
614 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
615 int zeroing)
617 unsigned i;
618 struct fuse_req *req = cs->req;
619 unsigned offset = req->page_offset;
620 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
622 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
623 struct page *page = req->pages[i];
624 int err = fuse_copy_page(cs, page, offset, count, zeroing);
625 if (err)
626 return err;
628 nbytes -= count;
629 count = min(nbytes, (unsigned) PAGE_SIZE);
630 offset = 0;
632 return 0;
635 /* Copy a single argument in the request to/from userspace buffer */
636 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
638 while (size) {
639 if (!cs->len) {
640 int err = fuse_copy_fill(cs);
641 if (err)
642 return err;
644 fuse_copy_do(cs, &val, &size);
646 return 0;
649 /* Copy request arguments to/from userspace buffer */
650 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
651 unsigned argpages, struct fuse_arg *args,
652 int zeroing)
654 int err = 0;
655 unsigned i;
657 for (i = 0; !err && i < numargs; i++) {
658 struct fuse_arg *arg = &args[i];
659 if (i == numargs - 1 && argpages)
660 err = fuse_copy_pages(cs, arg->size, zeroing);
661 else
662 err = fuse_copy_one(cs, arg->value, arg->size);
664 return err;
667 static int request_pending(struct fuse_conn *fc)
669 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
672 /* Wait until a request is available on the pending list */
673 static void request_wait(struct fuse_conn *fc)
674 __releases(&fc->lock)
675 __acquires(&fc->lock)
677 DECLARE_WAITQUEUE(wait, current);
679 add_wait_queue_exclusive(&fc->waitq, &wait);
680 while (fc->connected && !request_pending(fc)) {
681 set_current_state(TASK_INTERRUPTIBLE);
682 if (signal_pending(current))
683 break;
685 spin_unlock(&fc->lock);
686 schedule();
687 spin_lock(&fc->lock);
689 set_current_state(TASK_RUNNING);
690 remove_wait_queue(&fc->waitq, &wait);
694 * Transfer an interrupt request to userspace
696 * Unlike other requests this is assembled on demand, without a need
697 * to allocate a separate fuse_req structure.
699 * Called with fc->lock held, releases it
701 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
702 const struct iovec *iov, unsigned long nr_segs)
703 __releases(&fc->lock)
705 struct fuse_copy_state cs;
706 struct fuse_in_header ih;
707 struct fuse_interrupt_in arg;
708 unsigned reqsize = sizeof(ih) + sizeof(arg);
709 int err;
711 list_del_init(&req->intr_entry);
712 req->intr_unique = fuse_get_unique(fc);
713 memset(&ih, 0, sizeof(ih));
714 memset(&arg, 0, sizeof(arg));
715 ih.len = reqsize;
716 ih.opcode = FUSE_INTERRUPT;
717 ih.unique = req->intr_unique;
718 arg.unique = req->in.h.unique;
720 spin_unlock(&fc->lock);
721 if (iov_length(iov, nr_segs) < reqsize)
722 return -EINVAL;
724 fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
725 err = fuse_copy_one(&cs, &ih, sizeof(ih));
726 if (!err)
727 err = fuse_copy_one(&cs, &arg, sizeof(arg));
728 fuse_copy_finish(&cs);
730 return err ? err : reqsize;
734 * Read a single request into the userspace filesystem's buffer. This
735 * function waits until a request is available, then removes it from
736 * the pending list and copies request data to userspace buffer. If
737 * no reply is needed (FORGET) or request has been aborted or there
738 * was an error during the copying then it's finished by calling
739 * request_end(). Otherwise add it to the processing list, and set
740 * the 'sent' flag.
742 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
743 unsigned long nr_segs, loff_t pos)
745 int err;
746 struct fuse_req *req;
747 struct fuse_in *in;
748 struct fuse_copy_state cs;
749 unsigned reqsize;
750 struct file *file = iocb->ki_filp;
751 struct fuse_conn *fc = fuse_get_conn(file);
752 if (!fc)
753 return -EPERM;
755 restart:
756 spin_lock(&fc->lock);
757 err = -EAGAIN;
758 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
759 !request_pending(fc))
760 goto err_unlock;
762 request_wait(fc);
763 err = -ENODEV;
764 if (!fc->connected)
765 goto err_unlock;
766 err = -ERESTARTSYS;
767 if (!request_pending(fc))
768 goto err_unlock;
770 if (!list_empty(&fc->interrupts)) {
771 req = list_entry(fc->interrupts.next, struct fuse_req,
772 intr_entry);
773 return fuse_read_interrupt(fc, req, iov, nr_segs);
776 req = list_entry(fc->pending.next, struct fuse_req, list);
777 req->state = FUSE_REQ_READING;
778 list_move(&req->list, &fc->io);
780 in = &req->in;
781 reqsize = in->h.len;
782 /* If request is too large, reply with an error and restart the read */
783 if (iov_length(iov, nr_segs) < reqsize) {
784 req->out.h.error = -EIO;
785 /* SETXATTR is special, since it may contain too large data */
786 if (in->h.opcode == FUSE_SETXATTR)
787 req->out.h.error = -E2BIG;
788 request_end(fc, req);
789 goto restart;
791 spin_unlock(&fc->lock);
792 fuse_copy_init(&cs, fc, 1, req, iov, nr_segs);
793 err = fuse_copy_one(&cs, &in->h, sizeof(in->h));
794 if (!err)
795 err = fuse_copy_args(&cs, in->numargs, in->argpages,
796 (struct fuse_arg *) in->args, 0);
797 fuse_copy_finish(&cs);
798 spin_lock(&fc->lock);
799 req->locked = 0;
800 if (req->aborted) {
801 request_end(fc, req);
802 return -ENODEV;
804 if (err) {
805 req->out.h.error = -EIO;
806 request_end(fc, req);
807 return err;
809 if (!req->isreply)
810 request_end(fc, req);
811 else {
812 req->state = FUSE_REQ_SENT;
813 list_move_tail(&req->list, &fc->processing);
814 if (req->interrupted)
815 queue_interrupt(fc, req);
816 spin_unlock(&fc->lock);
818 return reqsize;
820 err_unlock:
821 spin_unlock(&fc->lock);
822 return err;
825 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
826 struct fuse_copy_state *cs)
828 struct fuse_notify_poll_wakeup_out outarg;
829 int err = -EINVAL;
831 if (size != sizeof(outarg))
832 goto err;
834 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
835 if (err)
836 goto err;
838 fuse_copy_finish(cs);
839 return fuse_notify_poll_wakeup(fc, &outarg);
841 err:
842 fuse_copy_finish(cs);
843 return err;
846 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
847 unsigned int size, struct fuse_copy_state *cs)
849 switch (code) {
850 case FUSE_NOTIFY_POLL:
851 return fuse_notify_poll(fc, size, cs);
853 default:
854 fuse_copy_finish(cs);
855 return -EINVAL;
859 /* Look up request on processing list by unique ID */
860 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
862 struct list_head *entry;
864 list_for_each(entry, &fc->processing) {
865 struct fuse_req *req;
866 req = list_entry(entry, struct fuse_req, list);
867 if (req->in.h.unique == unique || req->intr_unique == unique)
868 return req;
870 return NULL;
873 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
874 unsigned nbytes)
876 unsigned reqsize = sizeof(struct fuse_out_header);
878 if (out->h.error)
879 return nbytes != reqsize ? -EINVAL : 0;
881 reqsize += len_args(out->numargs, out->args);
883 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
884 return -EINVAL;
885 else if (reqsize > nbytes) {
886 struct fuse_arg *lastarg = &out->args[out->numargs-1];
887 unsigned diffsize = reqsize - nbytes;
888 if (diffsize > lastarg->size)
889 return -EINVAL;
890 lastarg->size -= diffsize;
892 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
893 out->page_zeroing);
897 * Write a single reply to a request. First the header is copied from
898 * the write buffer. The request is then searched on the processing
899 * list by the unique ID found in the header. If found, then remove
900 * it from the list and copy the rest of the buffer to the request.
901 * The request is finished by calling request_end()
903 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
904 unsigned long nr_segs, loff_t pos)
906 int err;
907 unsigned nbytes = iov_length(iov, nr_segs);
908 struct fuse_req *req;
909 struct fuse_out_header oh;
910 struct fuse_copy_state cs;
911 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
912 if (!fc)
913 return -EPERM;
915 fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs);
916 if (nbytes < sizeof(struct fuse_out_header))
917 return -EINVAL;
919 err = fuse_copy_one(&cs, &oh, sizeof(oh));
920 if (err)
921 goto err_finish;
923 err = -EINVAL;
924 if (oh.len != nbytes)
925 goto err_finish;
928 * Zero oh.unique indicates unsolicited notification message
929 * and error contains notification code.
931 if (!oh.unique) {
932 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), &cs);
933 return err ? err : nbytes;
936 err = -EINVAL;
937 if (oh.error <= -1000 || oh.error > 0)
938 goto err_finish;
940 spin_lock(&fc->lock);
941 err = -ENOENT;
942 if (!fc->connected)
943 goto err_unlock;
945 req = request_find(fc, oh.unique);
946 if (!req)
947 goto err_unlock;
949 if (req->aborted) {
950 spin_unlock(&fc->lock);
951 fuse_copy_finish(&cs);
952 spin_lock(&fc->lock);
953 request_end(fc, req);
954 return -ENOENT;
956 /* Is it an interrupt reply? */
957 if (req->intr_unique == oh.unique) {
958 err = -EINVAL;
959 if (nbytes != sizeof(struct fuse_out_header))
960 goto err_unlock;
962 if (oh.error == -ENOSYS)
963 fc->no_interrupt = 1;
964 else if (oh.error == -EAGAIN)
965 queue_interrupt(fc, req);
967 spin_unlock(&fc->lock);
968 fuse_copy_finish(&cs);
969 return nbytes;
972 req->state = FUSE_REQ_WRITING;
973 list_move(&req->list, &fc->io);
974 req->out.h = oh;
975 req->locked = 1;
976 cs.req = req;
977 spin_unlock(&fc->lock);
979 err = copy_out_args(&cs, &req->out, nbytes);
980 fuse_copy_finish(&cs);
982 spin_lock(&fc->lock);
983 req->locked = 0;
984 if (!err) {
985 if (req->aborted)
986 err = -ENOENT;
987 } else if (!req->aborted)
988 req->out.h.error = -EIO;
989 request_end(fc, req);
991 return err ? err : nbytes;
993 err_unlock:
994 spin_unlock(&fc->lock);
995 err_finish:
996 fuse_copy_finish(&cs);
997 return err;
1000 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1002 unsigned mask = POLLOUT | POLLWRNORM;
1003 struct fuse_conn *fc = fuse_get_conn(file);
1004 if (!fc)
1005 return POLLERR;
1007 poll_wait(file, &fc->waitq, wait);
1009 spin_lock(&fc->lock);
1010 if (!fc->connected)
1011 mask = POLLERR;
1012 else if (request_pending(fc))
1013 mask |= POLLIN | POLLRDNORM;
1014 spin_unlock(&fc->lock);
1016 return mask;
1020 * Abort all requests on the given list (pending or processing)
1022 * This function releases and reacquires fc->lock
1024 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1025 __releases(&fc->lock)
1026 __acquires(&fc->lock)
1028 while (!list_empty(head)) {
1029 struct fuse_req *req;
1030 req = list_entry(head->next, struct fuse_req, list);
1031 req->out.h.error = -ECONNABORTED;
1032 request_end(fc, req);
1033 spin_lock(&fc->lock);
1038 * Abort requests under I/O
1040 * The requests are set to aborted and finished, and the request
1041 * waiter is woken up. This will make request_wait_answer() wait
1042 * until the request is unlocked and then return.
1044 * If the request is asynchronous, then the end function needs to be
1045 * called after waiting for the request to be unlocked (if it was
1046 * locked).
1048 static void end_io_requests(struct fuse_conn *fc)
1049 __releases(&fc->lock)
1050 __acquires(&fc->lock)
1052 while (!list_empty(&fc->io)) {
1053 struct fuse_req *req =
1054 list_entry(fc->io.next, struct fuse_req, list);
1055 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1057 req->aborted = 1;
1058 req->out.h.error = -ECONNABORTED;
1059 req->state = FUSE_REQ_FINISHED;
1060 list_del_init(&req->list);
1061 wake_up(&req->waitq);
1062 if (end) {
1063 req->end = NULL;
1064 __fuse_get_request(req);
1065 spin_unlock(&fc->lock);
1066 wait_event(req->waitq, !req->locked);
1067 end(fc, req);
1068 fuse_put_request(fc, req);
1069 spin_lock(&fc->lock);
1075 * Abort all requests.
1077 * Emergency exit in case of a malicious or accidental deadlock, or
1078 * just a hung filesystem.
1080 * The same effect is usually achievable through killing the
1081 * filesystem daemon and all users of the filesystem. The exception
1082 * is the combination of an asynchronous request and the tricky
1083 * deadlock (see Documentation/filesystems/fuse.txt).
1085 * During the aborting, progression of requests from the pending and
1086 * processing lists onto the io list, and progression of new requests
1087 * onto the pending list is prevented by req->connected being false.
1089 * Progression of requests under I/O to the processing list is
1090 * prevented by the req->aborted flag being true for these requests.
1091 * For this reason requests on the io list must be aborted first.
1093 void fuse_abort_conn(struct fuse_conn *fc)
1095 spin_lock(&fc->lock);
1096 if (fc->connected) {
1097 fc->connected = 0;
1098 fc->blocked = 0;
1099 end_io_requests(fc);
1100 end_requests(fc, &fc->pending);
1101 end_requests(fc, &fc->processing);
1102 wake_up_all(&fc->waitq);
1103 wake_up_all(&fc->blocked_waitq);
1104 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1106 spin_unlock(&fc->lock);
1109 static int fuse_dev_release(struct inode *inode, struct file *file)
1111 struct fuse_conn *fc = fuse_get_conn(file);
1112 if (fc) {
1113 spin_lock(&fc->lock);
1114 fc->connected = 0;
1115 end_requests(fc, &fc->pending);
1116 end_requests(fc, &fc->processing);
1117 spin_unlock(&fc->lock);
1118 fuse_conn_put(fc);
1121 return 0;
1124 static int fuse_dev_fasync(int fd, struct file *file, int on)
1126 struct fuse_conn *fc = fuse_get_conn(file);
1127 if (!fc)
1128 return -EPERM;
1130 /* No locking - fasync_helper does its own locking */
1131 return fasync_helper(fd, file, on, &fc->fasync);
1134 const struct file_operations fuse_dev_operations = {
1135 .owner = THIS_MODULE,
1136 .llseek = no_llseek,
1137 .read = do_sync_read,
1138 .aio_read = fuse_dev_read,
1139 .write = do_sync_write,
1140 .aio_write = fuse_dev_write,
1141 .poll = fuse_dev_poll,
1142 .release = fuse_dev_release,
1143 .fasync = fuse_dev_fasync,
1146 static struct miscdevice fuse_miscdevice = {
1147 .minor = FUSE_MINOR,
1148 .name = "fuse",
1149 .fops = &fuse_dev_operations,
1152 int __init fuse_dev_init(void)
1154 int err = -ENOMEM;
1155 fuse_req_cachep = kmem_cache_create("fuse_request",
1156 sizeof(struct fuse_req),
1157 0, 0, NULL);
1158 if (!fuse_req_cachep)
1159 goto out;
1161 err = misc_register(&fuse_miscdevice);
1162 if (err)
1163 goto out_cache_clean;
1165 return 0;
1167 out_cache_clean:
1168 kmem_cache_destroy(fuse_req_cachep);
1169 out:
1170 return err;
1173 void fuse_dev_cleanup(void)
1175 misc_deregister(&fuse_miscdevice);
1176 kmem_cache_destroy(fuse_req_cachep);