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.
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);
21 MODULE_ALIAS("devname:fuse");
23 static struct kmem_cache *fuse_req_cachep;
25 static struct fuse_conn *fuse_get_conn(struct file *file)
28 * Lockless access is OK, because file->private data is set
29 * once during mount and is valid until the file is released.
31 return file->private_data;
34 static void fuse_request_init(struct fuse_req *req)
36 memset(req, 0, sizeof(*req));
37 INIT_LIST_HEAD(&req->list);
38 INIT_LIST_HEAD(&req->intr_entry);
39 init_waitqueue_head(&req->waitq);
40 atomic_set(&req->count, 1);
43 struct fuse_req *fuse_request_alloc(void)
45 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
47 fuse_request_init(req);
50 EXPORT_SYMBOL_GPL(fuse_request_alloc);
52 struct fuse_req *fuse_request_alloc_nofs(void)
54 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
56 fuse_request_init(req);
60 void fuse_request_free(struct fuse_req *req)
62 kmem_cache_free(fuse_req_cachep, req);
65 static void block_sigs(sigset_t *oldset)
69 siginitsetinv(&mask, sigmask(SIGKILL));
70 sigprocmask(SIG_BLOCK, &mask, oldset);
73 static void restore_sigs(sigset_t *oldset)
75 sigprocmask(SIG_SETMASK, oldset, NULL);
78 static void __fuse_get_request(struct fuse_req *req)
80 atomic_inc(&req->count);
83 /* Must be called with > 1 refcount */
84 static void __fuse_put_request(struct fuse_req *req)
86 BUG_ON(atomic_read(&req->count) < 2);
87 atomic_dec(&req->count);
90 static void fuse_req_init_context(struct fuse_req *req)
92 req->in.h.uid = current_fsuid();
93 req->in.h.gid = current_fsgid();
94 req->in.h.pid = current->pid;
97 struct fuse_req *fuse_get_req(struct fuse_conn *fc)
104 atomic_inc(&fc->num_waiting);
106 intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
107 restore_sigs(&oldset);
116 req = fuse_request_alloc();
121 fuse_req_init_context(req);
126 atomic_dec(&fc->num_waiting);
129 EXPORT_SYMBOL_GPL(fuse_get_req);
132 * Return request in fuse_file->reserved_req. However that may
133 * currently be in use. If that is the case, wait for it to become
136 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
139 struct fuse_req *req = NULL;
140 struct fuse_file *ff = file->private_data;
143 wait_event(fc->reserved_req_waitq, ff->reserved_req);
144 spin_lock(&fc->lock);
145 if (ff->reserved_req) {
146 req = ff->reserved_req;
147 ff->reserved_req = NULL;
149 req->stolen_file = file;
151 spin_unlock(&fc->lock);
158 * Put stolen request back into fuse_file->reserved_req
160 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
162 struct file *file = req->stolen_file;
163 struct fuse_file *ff = file->private_data;
165 spin_lock(&fc->lock);
166 fuse_request_init(req);
167 BUG_ON(ff->reserved_req);
168 ff->reserved_req = req;
169 wake_up_all(&fc->reserved_req_waitq);
170 spin_unlock(&fc->lock);
175 * Gets a requests for a file operation, always succeeds
177 * This is used for sending the FLUSH request, which must get to
178 * userspace, due to POSIX locks which may need to be unlocked.
180 * If allocation fails due to OOM, use the reserved request in
183 * This is very unlikely to deadlock accidentally, since the
184 * filesystem should not have it's own file open. If deadlock is
185 * intentional, it can still be broken by "aborting" the filesystem.
187 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
189 struct fuse_req *req;
191 atomic_inc(&fc->num_waiting);
192 wait_event(fc->blocked_waitq, !fc->blocked);
193 req = fuse_request_alloc();
195 req = get_reserved_req(fc, file);
197 fuse_req_init_context(req);
202 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
204 if (atomic_dec_and_test(&req->count)) {
206 atomic_dec(&fc->num_waiting);
208 if (req->stolen_file)
209 put_reserved_req(fc, req);
211 fuse_request_free(req);
214 EXPORT_SYMBOL_GPL(fuse_put_request);
216 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
221 for (i = 0; i < numargs; i++)
222 nbytes += args[i].size;
227 static u64 fuse_get_unique(struct fuse_conn *fc)
230 /* zero is special */
237 static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
239 req->in.h.unique = fuse_get_unique(fc);
240 req->in.h.len = sizeof(struct fuse_in_header) +
241 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
242 list_add_tail(&req->list, &fc->pending);
243 req->state = FUSE_REQ_PENDING;
246 atomic_inc(&fc->num_waiting);
249 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
252 static void flush_bg_queue(struct fuse_conn *fc)
254 while (fc->active_background < fc->max_background &&
255 !list_empty(&fc->bg_queue)) {
256 struct fuse_req *req;
258 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
259 list_del(&req->list);
260 fc->active_background++;
261 queue_request(fc, req);
266 * This function is called when a request is finished. Either a reply
267 * has arrived or it was aborted (and not yet sent) or some error
268 * occurred during communication with userspace, or the device file
269 * was closed. The requester thread is woken up (if still waiting),
270 * the 'end' callback is called if given, else the reference to the
271 * request is released
273 * Called with fc->lock, unlocks it
275 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
276 __releases(&fc->lock)
278 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
280 list_del(&req->list);
281 list_del(&req->intr_entry);
282 req->state = FUSE_REQ_FINISHED;
283 if (req->background) {
284 if (fc->num_background == fc->max_background) {
286 wake_up_all(&fc->blocked_waitq);
288 if (fc->num_background == fc->congestion_threshold &&
289 fc->connected && fc->bdi_initialized) {
290 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
291 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
293 fc->num_background--;
294 fc->active_background--;
297 spin_unlock(&fc->lock);
298 wake_up(&req->waitq);
301 fuse_put_request(fc, req);
304 static void wait_answer_interruptible(struct fuse_conn *fc,
305 struct fuse_req *req)
306 __releases(&fc->lock)
307 __acquires(&fc->lock)
309 if (signal_pending(current))
312 spin_unlock(&fc->lock);
313 wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
314 spin_lock(&fc->lock);
317 static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
319 list_add_tail(&req->intr_entry, &fc->interrupts);
321 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
324 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
325 __releases(&fc->lock)
326 __acquires(&fc->lock)
328 if (!fc->no_interrupt) {
329 /* Any signal may interrupt this */
330 wait_answer_interruptible(fc, req);
334 if (req->state == FUSE_REQ_FINISHED)
337 req->interrupted = 1;
338 if (req->state == FUSE_REQ_SENT)
339 queue_interrupt(fc, req);
345 /* Only fatal signals may interrupt this */
347 wait_answer_interruptible(fc, req);
348 restore_sigs(&oldset);
352 if (req->state == FUSE_REQ_FINISHED)
355 /* Request is not yet in userspace, bail out */
356 if (req->state == FUSE_REQ_PENDING) {
357 list_del(&req->list);
358 __fuse_put_request(req);
359 req->out.h.error = -EINTR;
365 * Either request is already in userspace, or it was forced.
368 spin_unlock(&fc->lock);
369 wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
370 spin_lock(&fc->lock);
376 BUG_ON(req->state != FUSE_REQ_FINISHED);
378 /* This is uninterruptible sleep, because data is
379 being copied to/from the buffers of req. During
380 locked state, there mustn't be any filesystem
381 operation (e.g. page fault), since that could lead
383 spin_unlock(&fc->lock);
384 wait_event(req->waitq, !req->locked);
385 spin_lock(&fc->lock);
389 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
392 spin_lock(&fc->lock);
394 req->out.h.error = -ENOTCONN;
395 else if (fc->conn_error)
396 req->out.h.error = -ECONNREFUSED;
398 queue_request(fc, req);
399 /* acquire extra reference, since request is still needed
400 after request_end() */
401 __fuse_get_request(req);
403 request_wait_answer(fc, req);
405 spin_unlock(&fc->lock);
407 EXPORT_SYMBOL_GPL(fuse_request_send);
409 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
410 struct fuse_req *req)
413 fc->num_background++;
414 if (fc->num_background == fc->max_background)
416 if (fc->num_background == fc->congestion_threshold &&
417 fc->bdi_initialized) {
418 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
419 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
421 list_add_tail(&req->list, &fc->bg_queue);
425 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
427 spin_lock(&fc->lock);
429 fuse_request_send_nowait_locked(fc, req);
430 spin_unlock(&fc->lock);
432 req->out.h.error = -ENOTCONN;
433 request_end(fc, req);
437 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
440 fuse_request_send_nowait(fc, req);
443 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
446 fuse_request_send_nowait(fc, req);
448 EXPORT_SYMBOL_GPL(fuse_request_send_background);
451 * Called under fc->lock
453 * fc->connected must have been checked previously
455 void fuse_request_send_background_locked(struct fuse_conn *fc,
456 struct fuse_req *req)
459 fuse_request_send_nowait_locked(fc, req);
463 * Lock the request. Up to the next unlock_request() there mustn't be
464 * anything that could cause a page-fault. If the request was already
467 static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
471 spin_lock(&fc->lock);
476 spin_unlock(&fc->lock);
482 * Unlock request. If it was aborted during being locked, the
483 * requester thread is currently waiting for it to be unlocked, so
486 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
489 spin_lock(&fc->lock);
492 wake_up(&req->waitq);
493 spin_unlock(&fc->lock);
497 struct fuse_copy_state {
498 struct fuse_conn *fc;
500 struct fuse_req *req;
501 const struct iovec *iov;
502 unsigned long nr_segs;
503 unsigned long seglen;
511 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
512 int write, struct fuse_req *req,
513 const struct iovec *iov, unsigned long nr_segs)
515 memset(cs, 0, sizeof(*cs));
520 cs->nr_segs = nr_segs;
523 /* Unmap and put previous page of userspace buffer */
524 static void fuse_copy_finish(struct fuse_copy_state *cs)
527 kunmap_atomic(cs->mapaddr, KM_USER0);
529 flush_dcache_page(cs->pg);
530 set_page_dirty_lock(cs->pg);
538 * Get another pagefull of userspace buffer, and map it to kernel
539 * address space, and lock request
541 static int fuse_copy_fill(struct fuse_copy_state *cs)
543 unsigned long offset;
546 unlock_request(cs->fc, cs->req);
547 fuse_copy_finish(cs);
549 BUG_ON(!cs->nr_segs);
550 cs->seglen = cs->iov[0].iov_len;
551 cs->addr = (unsigned long) cs->iov[0].iov_base;
555 down_read(¤t->mm->mmap_sem);
556 err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0,
558 up_read(¤t->mm->mmap_sem);
562 offset = cs->addr % PAGE_SIZE;
563 cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
564 cs->buf = cs->mapaddr + offset;
565 cs->len = min(PAGE_SIZE - offset, cs->seglen);
566 cs->seglen -= cs->len;
569 return lock_request(cs->fc, cs->req);
572 /* Do as much copy to/from userspace buffer as we can */
573 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
575 unsigned ncpy = min(*size, cs->len);
578 memcpy(cs->buf, *val, ncpy);
580 memcpy(*val, cs->buf, ncpy);
590 * Copy a page in the request to/from the userspace buffer. Must be
593 static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page,
594 unsigned offset, unsigned count, int zeroing)
596 if (page && zeroing && count < PAGE_SIZE) {
597 void *mapaddr = kmap_atomic(page, KM_USER1);
598 memset(mapaddr, 0, PAGE_SIZE);
599 kunmap_atomic(mapaddr, KM_USER1);
603 int err = fuse_copy_fill(cs);
608 void *mapaddr = kmap_atomic(page, KM_USER1);
609 void *buf = mapaddr + offset;
610 offset += fuse_copy_do(cs, &buf, &count);
611 kunmap_atomic(mapaddr, KM_USER1);
613 offset += fuse_copy_do(cs, NULL, &count);
615 if (page && !cs->write)
616 flush_dcache_page(page);
620 /* Copy pages in the request to/from userspace buffer */
621 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
625 struct fuse_req *req = cs->req;
626 unsigned offset = req->page_offset;
627 unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
629 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
630 struct page *page = req->pages[i];
631 int err = fuse_copy_page(cs, page, offset, count, zeroing);
636 count = min(nbytes, (unsigned) PAGE_SIZE);
642 /* Copy a single argument in the request to/from userspace buffer */
643 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
647 int err = fuse_copy_fill(cs);
651 fuse_copy_do(cs, &val, &size);
656 /* Copy request arguments to/from userspace buffer */
657 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
658 unsigned argpages, struct fuse_arg *args,
664 for (i = 0; !err && i < numargs; i++) {
665 struct fuse_arg *arg = &args[i];
666 if (i == numargs - 1 && argpages)
667 err = fuse_copy_pages(cs, arg->size, zeroing);
669 err = fuse_copy_one(cs, arg->value, arg->size);
674 static int request_pending(struct fuse_conn *fc)
676 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
679 /* Wait until a request is available on the pending list */
680 static void request_wait(struct fuse_conn *fc)
681 __releases(&fc->lock)
682 __acquires(&fc->lock)
684 DECLARE_WAITQUEUE(wait, current);
686 add_wait_queue_exclusive(&fc->waitq, &wait);
687 while (fc->connected && !request_pending(fc)) {
688 set_current_state(TASK_INTERRUPTIBLE);
689 if (signal_pending(current))
692 spin_unlock(&fc->lock);
694 spin_lock(&fc->lock);
696 set_current_state(TASK_RUNNING);
697 remove_wait_queue(&fc->waitq, &wait);
701 * Transfer an interrupt request to userspace
703 * Unlike other requests this is assembled on demand, without a need
704 * to allocate a separate fuse_req structure.
706 * Called with fc->lock held, releases it
708 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
709 const struct iovec *iov, unsigned long nr_segs)
710 __releases(&fc->lock)
712 struct fuse_copy_state cs;
713 struct fuse_in_header ih;
714 struct fuse_interrupt_in arg;
715 unsigned reqsize = sizeof(ih) + sizeof(arg);
718 list_del_init(&req->intr_entry);
719 req->intr_unique = fuse_get_unique(fc);
720 memset(&ih, 0, sizeof(ih));
721 memset(&arg, 0, sizeof(arg));
723 ih.opcode = FUSE_INTERRUPT;
724 ih.unique = req->intr_unique;
725 arg.unique = req->in.h.unique;
727 spin_unlock(&fc->lock);
728 if (iov_length(iov, nr_segs) < reqsize)
731 fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
732 err = fuse_copy_one(&cs, &ih, sizeof(ih));
734 err = fuse_copy_one(&cs, &arg, sizeof(arg));
735 fuse_copy_finish(&cs);
737 return err ? err : reqsize;
741 * Read a single request into the userspace filesystem's buffer. This
742 * function waits until a request is available, then removes it from
743 * the pending list and copies request data to userspace buffer. If
744 * no reply is needed (FORGET) or request has been aborted or there
745 * was an error during the copying then it's finished by calling
746 * request_end(). Otherwise add it to the processing list, and set
749 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
750 unsigned long nr_segs, loff_t pos)
753 struct fuse_req *req;
755 struct fuse_copy_state cs;
757 struct file *file = iocb->ki_filp;
758 struct fuse_conn *fc = fuse_get_conn(file);
763 spin_lock(&fc->lock);
765 if ((file->f_flags & O_NONBLOCK) && fc->connected &&
766 !request_pending(fc))
774 if (!request_pending(fc))
777 if (!list_empty(&fc->interrupts)) {
778 req = list_entry(fc->interrupts.next, struct fuse_req,
780 return fuse_read_interrupt(fc, req, iov, nr_segs);
783 req = list_entry(fc->pending.next, struct fuse_req, list);
784 req->state = FUSE_REQ_READING;
785 list_move(&req->list, &fc->io);
789 /* If request is too large, reply with an error and restart the read */
790 if (iov_length(iov, nr_segs) < reqsize) {
791 req->out.h.error = -EIO;
792 /* SETXATTR is special, since it may contain too large data */
793 if (in->h.opcode == FUSE_SETXATTR)
794 req->out.h.error = -E2BIG;
795 request_end(fc, req);
798 spin_unlock(&fc->lock);
799 fuse_copy_init(&cs, fc, 1, req, iov, nr_segs);
800 err = fuse_copy_one(&cs, &in->h, sizeof(in->h));
802 err = fuse_copy_args(&cs, in->numargs, in->argpages,
803 (struct fuse_arg *) in->args, 0);
804 fuse_copy_finish(&cs);
805 spin_lock(&fc->lock);
808 request_end(fc, req);
812 req->out.h.error = -EIO;
813 request_end(fc, req);
817 request_end(fc, req);
819 req->state = FUSE_REQ_SENT;
820 list_move_tail(&req->list, &fc->processing);
821 if (req->interrupted)
822 queue_interrupt(fc, req);
823 spin_unlock(&fc->lock);
828 spin_unlock(&fc->lock);
832 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
833 struct fuse_copy_state *cs)
835 struct fuse_notify_poll_wakeup_out outarg;
838 if (size != sizeof(outarg))
841 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
845 fuse_copy_finish(cs);
846 return fuse_notify_poll_wakeup(fc, &outarg);
849 fuse_copy_finish(cs);
853 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
854 struct fuse_copy_state *cs)
856 struct fuse_notify_inval_inode_out outarg;
859 if (size != sizeof(outarg))
862 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
865 fuse_copy_finish(cs);
867 down_read(&fc->killsb);
870 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
871 outarg.off, outarg.len);
873 up_read(&fc->killsb);
877 fuse_copy_finish(cs);
881 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
882 struct fuse_copy_state *cs)
884 struct fuse_notify_inval_entry_out outarg;
889 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
894 if (size < sizeof(outarg))
897 err = fuse_copy_one(cs, &outarg, sizeof(outarg));
902 if (outarg.namelen > FUSE_NAME_MAX)
906 name.len = outarg.namelen;
907 err = fuse_copy_one(cs, buf, outarg.namelen + 1);
910 fuse_copy_finish(cs);
911 buf[outarg.namelen] = 0;
912 name.hash = full_name_hash(name.name, name.len);
914 down_read(&fc->killsb);
917 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name);
918 up_read(&fc->killsb);
924 fuse_copy_finish(cs);
928 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
929 unsigned int size, struct fuse_copy_state *cs)
932 case FUSE_NOTIFY_POLL:
933 return fuse_notify_poll(fc, size, cs);
935 case FUSE_NOTIFY_INVAL_INODE:
936 return fuse_notify_inval_inode(fc, size, cs);
938 case FUSE_NOTIFY_INVAL_ENTRY:
939 return fuse_notify_inval_entry(fc, size, cs);
942 fuse_copy_finish(cs);
947 /* Look up request on processing list by unique ID */
948 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
950 struct list_head *entry;
952 list_for_each(entry, &fc->processing) {
953 struct fuse_req *req;
954 req = list_entry(entry, struct fuse_req, list);
955 if (req->in.h.unique == unique || req->intr_unique == unique)
961 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
964 unsigned reqsize = sizeof(struct fuse_out_header);
967 return nbytes != reqsize ? -EINVAL : 0;
969 reqsize += len_args(out->numargs, out->args);
971 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
973 else if (reqsize > nbytes) {
974 struct fuse_arg *lastarg = &out->args[out->numargs-1];
975 unsigned diffsize = reqsize - nbytes;
976 if (diffsize > lastarg->size)
978 lastarg->size -= diffsize;
980 return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
985 * Write a single reply to a request. First the header is copied from
986 * the write buffer. The request is then searched on the processing
987 * list by the unique ID found in the header. If found, then remove
988 * it from the list and copy the rest of the buffer to the request.
989 * The request is finished by calling request_end()
991 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
992 unsigned long nr_segs, loff_t pos)
995 size_t nbytes = iov_length(iov, nr_segs);
996 struct fuse_req *req;
997 struct fuse_out_header oh;
998 struct fuse_copy_state cs;
999 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1003 fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs);
1004 if (nbytes < sizeof(struct fuse_out_header))
1007 err = fuse_copy_one(&cs, &oh, sizeof(oh));
1012 if (oh.len != nbytes)
1016 * Zero oh.unique indicates unsolicited notification message
1017 * and error contains notification code.
1020 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), &cs);
1021 return err ? err : nbytes;
1025 if (oh.error <= -1000 || oh.error > 0)
1028 spin_lock(&fc->lock);
1033 req = request_find(fc, oh.unique);
1038 spin_unlock(&fc->lock);
1039 fuse_copy_finish(&cs);
1040 spin_lock(&fc->lock);
1041 request_end(fc, req);
1044 /* Is it an interrupt reply? */
1045 if (req->intr_unique == oh.unique) {
1047 if (nbytes != sizeof(struct fuse_out_header))
1050 if (oh.error == -ENOSYS)
1051 fc->no_interrupt = 1;
1052 else if (oh.error == -EAGAIN)
1053 queue_interrupt(fc, req);
1055 spin_unlock(&fc->lock);
1056 fuse_copy_finish(&cs);
1060 req->state = FUSE_REQ_WRITING;
1061 list_move(&req->list, &fc->io);
1065 spin_unlock(&fc->lock);
1067 err = copy_out_args(&cs, &req->out, nbytes);
1068 fuse_copy_finish(&cs);
1070 spin_lock(&fc->lock);
1075 } else if (!req->aborted)
1076 req->out.h.error = -EIO;
1077 request_end(fc, req);
1079 return err ? err : nbytes;
1082 spin_unlock(&fc->lock);
1084 fuse_copy_finish(&cs);
1088 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1090 unsigned mask = POLLOUT | POLLWRNORM;
1091 struct fuse_conn *fc = fuse_get_conn(file);
1095 poll_wait(file, &fc->waitq, wait);
1097 spin_lock(&fc->lock);
1100 else if (request_pending(fc))
1101 mask |= POLLIN | POLLRDNORM;
1102 spin_unlock(&fc->lock);
1108 * Abort all requests on the given list (pending or processing)
1110 * This function releases and reacquires fc->lock
1112 static void end_requests(struct fuse_conn *fc, struct list_head *head)
1113 __releases(&fc->lock)
1114 __acquires(&fc->lock)
1116 while (!list_empty(head)) {
1117 struct fuse_req *req;
1118 req = list_entry(head->next, struct fuse_req, list);
1119 req->out.h.error = -ECONNABORTED;
1120 request_end(fc, req);
1121 spin_lock(&fc->lock);
1126 * Abort requests under I/O
1128 * The requests are set to aborted and finished, and the request
1129 * waiter is woken up. This will make request_wait_answer() wait
1130 * until the request is unlocked and then return.
1132 * If the request is asynchronous, then the end function needs to be
1133 * called after waiting for the request to be unlocked (if it was
1136 static void end_io_requests(struct fuse_conn *fc)
1137 __releases(&fc->lock)
1138 __acquires(&fc->lock)
1140 while (!list_empty(&fc->io)) {
1141 struct fuse_req *req =
1142 list_entry(fc->io.next, struct fuse_req, list);
1143 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
1146 req->out.h.error = -ECONNABORTED;
1147 req->state = FUSE_REQ_FINISHED;
1148 list_del_init(&req->list);
1149 wake_up(&req->waitq);
1152 __fuse_get_request(req);
1153 spin_unlock(&fc->lock);
1154 wait_event(req->waitq, !req->locked);
1156 fuse_put_request(fc, req);
1157 spin_lock(&fc->lock);
1163 * Abort all requests.
1165 * Emergency exit in case of a malicious or accidental deadlock, or
1166 * just a hung filesystem.
1168 * The same effect is usually achievable through killing the
1169 * filesystem daemon and all users of the filesystem. The exception
1170 * is the combination of an asynchronous request and the tricky
1171 * deadlock (see Documentation/filesystems/fuse.txt).
1173 * During the aborting, progression of requests from the pending and
1174 * processing lists onto the io list, and progression of new requests
1175 * onto the pending list is prevented by req->connected being false.
1177 * Progression of requests under I/O to the processing list is
1178 * prevented by the req->aborted flag being true for these requests.
1179 * For this reason requests on the io list must be aborted first.
1181 void fuse_abort_conn(struct fuse_conn *fc)
1183 spin_lock(&fc->lock);
1184 if (fc->connected) {
1187 end_io_requests(fc);
1188 end_requests(fc, &fc->pending);
1189 end_requests(fc, &fc->processing);
1190 wake_up_all(&fc->waitq);
1191 wake_up_all(&fc->blocked_waitq);
1192 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
1194 spin_unlock(&fc->lock);
1196 EXPORT_SYMBOL_GPL(fuse_abort_conn);
1198 int fuse_dev_release(struct inode *inode, struct file *file)
1200 struct fuse_conn *fc = fuse_get_conn(file);
1202 spin_lock(&fc->lock);
1204 end_requests(fc, &fc->pending);
1205 end_requests(fc, &fc->processing);
1206 spin_unlock(&fc->lock);
1212 EXPORT_SYMBOL_GPL(fuse_dev_release);
1214 static int fuse_dev_fasync(int fd, struct file *file, int on)
1216 struct fuse_conn *fc = fuse_get_conn(file);
1220 /* No locking - fasync_helper does its own locking */
1221 return fasync_helper(fd, file, on, &fc->fasync);
1224 const struct file_operations fuse_dev_operations = {
1225 .owner = THIS_MODULE,
1226 .llseek = no_llseek,
1227 .read = do_sync_read,
1228 .aio_read = fuse_dev_read,
1229 .write = do_sync_write,
1230 .aio_write = fuse_dev_write,
1231 .poll = fuse_dev_poll,
1232 .release = fuse_dev_release,
1233 .fasync = fuse_dev_fasync,
1235 EXPORT_SYMBOL_GPL(fuse_dev_operations);
1237 static struct miscdevice fuse_miscdevice = {
1238 .minor = FUSE_MINOR,
1240 .fops = &fuse_dev_operations,
1243 int __init fuse_dev_init(void)
1246 fuse_req_cachep = kmem_cache_create("fuse_request",
1247 sizeof(struct fuse_req),
1249 if (!fuse_req_cachep)
1252 err = misc_register(&fuse_miscdevice);
1254 goto out_cache_clean;
1259 kmem_cache_destroy(fuse_req_cachep);
1264 void fuse_dev_cleanup(void)
1266 misc_deregister(&fuse_miscdevice);
1267 kmem_cache_destroy(fuse_req_cachep);