/* FUSE: Filesystem in Userspace Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include "fuse_i.h" #include <linux/init.h> #include <linux/module.h> #include <linux/poll.h> #include <linux/uio.h> #include <linux/miscdevice.h> #include <linux/pagemap.h> #include <linux/file.h> #include <linux/slab.h> #include <linux/pipe_fs_i.h> #include <linux/swap.h> #include <linux/splice.h> MODULE_ALIAS_MISCDEV(FUSE_MINOR); MODULE_ALIAS("devname:fuse"); static struct kmem_cache *fuse_req_cachep; static struct fuse_conn *fuse_get_conn(struct file *file) { /* * Lockless access is OK, because file->private data is set * once during mount and is valid until the file is released. */ return file->private_data; } static void fuse_request_init(struct fuse_req *req) { memset(req, 0, sizeof(*req)); INIT_LIST_HEAD(&req->list); INIT_LIST_HEAD(&req->intr_entry); init_waitqueue_head(&req->waitq); atomic_set(&req->count, 1); } struct fuse_req *fuse_request_alloc(void) { struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL); if (req) fuse_request_init(req); return req; } EXPORT_SYMBOL_GPL(fuse_request_alloc); struct fuse_req *fuse_request_alloc_nofs(void) { struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS); if (req) fuse_request_init(req); return req; } void fuse_request_free(struct fuse_req *req) { kmem_cache_free(fuse_req_cachep, req); } static void block_sigs(sigset_t *oldset) { sigset_t mask; siginitsetinv(&mask, sigmask(SIGKILL)); sigprocmask(SIG_BLOCK, &mask, oldset); } static void restore_sigs(sigset_t *oldset) { sigprocmask(SIG_SETMASK, oldset, NULL); } static void __fuse_get_request(struct fuse_req *req) { atomic_inc(&req->count); } /* Must be called with > 1 refcount */ static void __fuse_put_request(struct fuse_req *req) { BUG_ON(atomic_read(&req->count) < 2); atomic_dec(&req->count); } static void fuse_req_init_context(struct fuse_req *req) { req->in.h.uid = current_fsuid(); req->in.h.gid = current_fsgid(); req->in.h.pid = current->pid; } struct fuse_req *fuse_get_req(struct fuse_conn *fc) { struct fuse_req *req; sigset_t oldset; int intr; int err; atomic_inc(&fc->num_waiting); block_sigs(&oldset); intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked); restore_sigs(&oldset); err = -EINTR; if (intr) goto out; err = -ENOTCONN; if (!fc->connected) goto out; req = fuse_request_alloc(); err = -ENOMEM; if (!req) goto out; fuse_req_init_context(req); req->waiting = 1; return req; out: atomic_dec(&fc->num_waiting); return ERR_PTR(err); } EXPORT_SYMBOL_GPL(fuse_get_req); /* * Return request in fuse_file->reserved_req. However that may * currently be in use. If that is the case, wait for it to become * available. */ static struct fuse_req *get_reserved_req(struct fuse_conn *fc, struct file *file) { struct fuse_req *req = NULL; struct fuse_file *ff = file->private_data; do { wait_event(fc->reserved_req_waitq, ff->reserved_req); spin_lock(&fc->lock); if (ff->reserved_req) { req = ff->reserved_req; ff->reserved_req = NULL; get_file(file); req->stolen_file = file; } spin_unlock(&fc->lock); } while (!req); return req; } /* * Put stolen request back into fuse_file->reserved_req */ static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) { struct file *file = req->stolen_file; struct fuse_file *ff = file->private_data; spin_lock(&fc->lock); fuse_request_init(req); BUG_ON(ff->reserved_req); ff->reserved_req = req; wake_up_all(&fc->reserved_req_waitq); spin_unlock(&fc->lock); fput(file); } /* * Gets a requests for a file operation, always succeeds * * This is used for sending the FLUSH request, which must get to * userspace, due to POSIX locks which may need to be unlocked. * * If allocation fails due to OOM, use the reserved request in * fuse_file. * * This is very unlikely to deadlock accidentally, since the * filesystem should not have it's own file open. If deadlock is * intentional, it can still be broken by "aborting" the filesystem. */ struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file) { struct fuse_req *req; atomic_inc(&fc->num_waiting); wait_event(fc->blocked_waitq, !fc->blocked); req = fuse_request_alloc(); if (!req) req = get_reserved_req(fc, file); fuse_req_init_context(req); req->waiting = 1; return req; } void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) { if (atomic_dec_and_test(&req->count)) { if (req->waiting) atomic_dec(&fc->num_waiting); if (req->stolen_file) put_reserved_req(fc, req); else fuse_request_free(req); } } EXPORT_SYMBOL_GPL(fuse_put_request); static unsigned len_args(unsigned numargs, struct fuse_arg *args) { unsigned nbytes = 0; unsigned i; for (i = 0; i < numargs; i++) nbytes += args[i].size; return nbytes; } static u64 fuse_get_unique(struct fuse_conn *fc) { fc->reqctr++; /* zero is special */ if (fc->reqctr == 0) fc->reqctr = 1; return fc->reqctr; } static void queue_request(struct fuse_conn *fc, struct fuse_req *req) { req->in.h.unique = fuse_get_unique(fc); req->in.h.len = sizeof(struct fuse_in_header) + len_args(req->in.numargs, (struct fuse_arg *) req->in.args); list_add_tail(&req->list, &fc->pending); req->state = FUSE_REQ_PENDING; if (!req->waiting) { req->waiting = 1; atomic_inc(&fc->num_waiting); } wake_up(&fc->waitq); kill_fasync(&fc->fasync, SIGIO, POLL_IN); } static void flush_bg_queue(struct fuse_conn *fc) { while (fc->active_background < fc->max_background && !list_empty(&fc->bg_queue)) { struct fuse_req *req; req = list_entry(fc->bg_queue.next, struct fuse_req, list); list_del(&req->list); fc->active_background++; queue_request(fc, req); } } /* * This function is called when a request is finished. Either a reply * has arrived or it was aborted (and not yet sent) or some error * occurred during communication with userspace, or the device file * was closed. The requester thread is woken up (if still waiting), * the 'end' callback is called if given, else the reference to the * request is released * * Called with fc->lock, unlocks it */ static void request_end(struct fuse_conn *fc, struct fuse_req *req) __releases(&fc->lock) { void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; req->end = NULL; list_del(&req->list); list_del(&req->intr_entry); req->state = FUSE_REQ_FINISHED; if (req->background) { if (fc->num_background == fc->max_background) { fc->blocked = 0; wake_up_all(&fc->blocked_waitq); } if (fc->num_background == fc->congestion_threshold && fc->connected && fc->bdi_initialized) { clear_bdi_congested(&fc->bdi, BLK_RW_SYNC); clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC); } fc->num_background--; fc->active_background--; flush_bg_queue(fc); } spin_unlock(&fc->lock); wake_up(&req->waitq); if (end) end(fc, req); fuse_put_request(fc, req); } static void wait_answer_interruptible(struct fuse_conn *fc, struct fuse_req *req) __releases(&fc->lock) __acquires(&fc->lock) { if (signal_pending(current)) return; spin_unlock(&fc->lock); wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED); spin_lock(&fc->lock); } static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req) { list_add_tail(&req->intr_entry, &fc->interrupts); wake_up(&fc->waitq); kill_fasync(&fc->fasync, SIGIO, POLL_IN); } static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) __releases(&fc->lock) __acquires(&fc->lock) { if (!fc->no_interrupt) { /* Any signal may interrupt this */ wait_answer_interruptible(fc, req); if (req->aborted) goto aborted; if (req->state == FUSE_REQ_FINISHED) return; req->interrupted = 1; if (req->state == FUSE_REQ_SENT) queue_interrupt(fc, req); } if (!req->force) { sigset_t oldset; /* Only fatal signals may interrupt this */ block_sigs(&oldset); wait_answer_interruptible(fc, req); restore_sigs(&oldset); if (req->aborted) goto aborted; if (req->state == FUSE_REQ_FINISHED) return; /* Request is not yet in userspace, bail out */ if (req->state == FUSE_REQ_PENDING) { list_del(&req->list); __fuse_put_request(req); req->out.h.error = -EINTR; return; } } /* * Either request is already in userspace, or it was forced. * Wait it out. */ spin_unlock(&fc->lock); wait_event(req->waitq, req->state == FUSE_REQ_FINISHED); spin_lock(&fc->lock); if (!req->aborted) return; aborted: BUG_ON(req->state != FUSE_REQ_FINISHED); if (req->locked) { /* This is uninterruptible sleep, because data is being copied to/from the buffers of req. During locked state, there mustn't be any filesystem operation (e.g. page fault), since that could lead to deadlock */ spin_unlock(&fc->lock); wait_event(req->waitq, !req->locked); spin_lock(&fc->lock); } } void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 1; spin_lock(&fc->lock); if (!fc->connected) req->out.h.error = -ENOTCONN; else if (fc->conn_error) req->out.h.error = -ECONNREFUSED; else { queue_request(fc, req); /* acquire extra reference, since request is still needed after request_end() */ __fuse_get_request(req); request_wait_answer(fc, req); } spin_unlock(&fc->lock); } EXPORT_SYMBOL_GPL(fuse_request_send); static void fuse_request_send_nowait_locked(struct fuse_conn *fc, struct fuse_req *req) { req->background = 1; fc->num_background++; if (fc->num_background == fc->max_background) fc->blocked = 1; if (fc->num_background == fc->congestion_threshold && fc->bdi_initialized) { set_bdi_congested(&fc->bdi, BLK_RW_SYNC); set_bdi_congested(&fc->bdi, BLK_RW_ASYNC); } list_add_tail(&req->list, &fc->bg_queue); flush_bg_queue(fc); } static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req) { spin_lock(&fc->lock); if (fc->connected) { fuse_request_send_nowait_locked(fc, req); spin_unlock(&fc->lock); } else { req->out.h.error = -ENOTCONN; request_end(fc, req); } } void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 0; fuse_request_send_nowait(fc, req); } void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 1; fuse_request_send_nowait(fc, req); } EXPORT_SYMBOL_GPL(fuse_request_send_background); /* * Called under fc->lock * * fc->connected must have been checked previously */ void fuse_request_send_background_locked(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 1; fuse_request_send_nowait_locked(fc, req); } /* * Lock the request. Up to the next unlock_request() there mustn't be * anything that could cause a page-fault. If the request was already * aborted bail out. */ static int lock_request(struct fuse_conn *fc, struct fuse_req *req) { int err = 0; if (req) { spin_lock(&fc->lock); if (req->aborted) err = -ENOENT; else req->locked = 1; spin_unlock(&fc->lock); } return err; } /* * Unlock request. If it was aborted during being locked, the * requester thread is currently waiting for it to be unlocked, so * wake it up. */ static void unlock_request(struct fuse_conn *fc, struct fuse_req *req) { if (req) { spin_lock(&fc->lock); req->locked = 0; if (req->aborted) wake_up(&req->waitq); spin_unlock(&fc->lock); } } struct fuse_copy_state { struct fuse_conn *fc; int write; struct fuse_req *req; const struct iovec *iov; struct pipe_buffer *pipebufs; struct pipe_buffer *currbuf; struct pipe_inode_info *pipe; unsigned long nr_segs; unsigned long seglen; unsigned long addr; struct page *pg; void *mapaddr; void *buf; unsigned len; unsigned move_pages:1; }; static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc, int write, const struct iovec *iov, unsigned long nr_segs) { memset(cs, 0, sizeof(*cs)); cs->fc = fc; cs->write = write; cs->iov = iov; cs->nr_segs = nr_segs; } /* Unmap and put previous page of userspace buffer */ static void fuse_copy_finish(struct fuse_copy_state *cs) { if (cs->currbuf) { struct pipe_buffer *buf = cs->currbuf; if (!cs->write) { buf->ops->unmap(cs->pipe, buf, cs->mapaddr); } else { kunmap_atomic(cs->mapaddr, KM_USER0); buf->len = PAGE_SIZE - cs->len; } cs->currbuf = NULL; cs->mapaddr = NULL; } else if (cs->mapaddr) { kunmap_atomic(cs->mapaddr, KM_USER0); if (cs->write) { flush_dcache_page(cs->pg); set_page_dirty_lock(cs->pg); } put_page(cs->pg); cs->mapaddr = NULL; } } /* * Get another pagefull of userspace buffer, and map it to kernel * address space, and lock request */ static int fuse_copy_fill(struct fuse_copy_state *cs) { unsigned long offset; int err; unlock_request(cs->fc, cs->req); fuse_copy_finish(cs); if (cs->pipebufs) { struct pipe_buffer *buf = cs->pipebufs; if (!cs->write) { err = buf->ops->confirm(cs->pipe, buf); if (err) return err; BUG_ON(!cs->nr_segs); cs->currbuf = buf; cs->mapaddr = buf->ops->map(cs->pipe, buf, 1); cs->len = buf->len; cs->buf = cs->mapaddr + buf->offset; cs->pipebufs++; cs->nr_segs--; } else { struct page *page; if (cs->nr_segs == cs->pipe->buffers) return -EIO; page = alloc_page(GFP_HIGHUSER); if (!page) return -ENOMEM; buf->page = page; buf->offset = 0; buf->len = 0; cs->currbuf = buf; cs->mapaddr = kmap_atomic(page, KM_USER0); cs->buf = cs->mapaddr; cs->len = PAGE_SIZE; cs->pipebufs++; cs->nr_segs++; } } else { if (!cs->seglen) { BUG_ON(!cs->nr_segs); cs->seglen = cs->iov[0].iov_len; cs->addr = (unsigned long) cs->iov[0].iov_base; cs->iov++; cs->nr_segs--; } err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg); if (err < 0) return err; BUG_ON(err != 1); offset = cs->addr % PAGE_SIZE; cs->mapaddr = kmap_atomic(cs->pg, KM_USER0); cs->buf = cs->mapaddr + offset; cs->len = min(PAGE_SIZE - offset, cs->seglen); cs->seglen -= cs->len; cs->addr += cs->len; } return lock_request(cs->fc, cs->req); } /* Do as much copy to/from userspace buffer as we can */ static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) { unsigned ncpy = min(*size, cs->len); if (val) { if (cs->write) memcpy(cs->buf, *val, ncpy); else memcpy(*val, cs->buf, ncpy); *val += ncpy; } *size -= ncpy; cs->len -= ncpy; cs->buf += ncpy; return ncpy; } static int fuse_check_page(struct page *page) { if (page_mapcount(page) || page->mapping != NULL || page_count(page) != 1 || (page->flags & PAGE_FLAGS_CHECK_AT_PREP & ~(1 << PG_locked | 1 << PG_referenced | 1 << PG_uptodate | 1 << PG_lru | 1 << PG_active | 1 << PG_reclaim))) { printk(KERN_WARNING "fuse: trying to steal weird page\n"); printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping); return 1; } return 0; } static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) { int err; struct page *oldpage = *pagep; struct page *newpage; struct pipe_buffer *buf = cs->pipebufs; struct address_space *mapping; pgoff_t index; unlock_request(cs->fc, cs->req); fuse_copy_finish(cs); err = buf->ops->confirm(cs->pipe, buf); if (err) return err; BUG_ON(!cs->nr_segs); cs->currbuf = buf; cs->len = buf->len; cs->pipebufs++; cs->nr_segs--; if (cs->len != PAGE_SIZE) goto out_fallback; if (buf->ops->steal(cs->pipe, buf) != 0) goto out_fallback; newpage = buf->page; if (WARN_ON(!PageUptodate(newpage))) return -EIO; ClearPageMappedToDisk(newpage); if (fuse_check_page(newpage) != 0) goto out_fallback_unlock; mapping = oldpage->mapping; index = oldpage->index; /* * This is a new and locked page, it shouldn't be mapped or * have any special flags on it */ if (WARN_ON(page_mapped(oldpage))) goto out_fallback_unlock; if (WARN_ON(page_has_private(oldpage))) goto out_fallback_unlock; if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) goto out_fallback_unlock; if (WARN_ON(PageMlocked(oldpage))) goto out_fallback_unlock; remove_from_page_cache(oldpage); page_cache_release(oldpage); err = add_to_page_cache_locked(newpage, mapping, index, GFP_KERNEL); if (err) { printk(KERN_WARNING "fuse_try_move_page: failed to add page"); goto out_fallback_unlock; } page_cache_get(newpage); if (!(buf->flags & PIPE_BUF_FLAG_LRU)) lru_cache_add_file(newpage); err = 0; spin_lock(&cs->fc->lock); if (cs->req->aborted) err = -ENOENT; else *pagep = newpage; spin_unlock(&cs->fc->lock); if (err) { unlock_page(newpage); page_cache_release(newpage); return err; } unlock_page(oldpage); page_cache_release(oldpage); cs->len = 0; return 0; out_fallback_unlock: unlock_page(newpage); out_fallback: cs->mapaddr = buf->ops->map(cs->pipe, buf, 1); cs->buf = cs->mapaddr + buf->offset; err = lock_request(cs->fc, cs->req); if (err) return err; return 1; } static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, unsigned offset, unsigned count) { struct pipe_buffer *buf; if (cs->nr_segs == cs->pipe->buffers) return -EIO; unlock_request(cs->fc, cs->req); fuse_copy_finish(cs); buf = cs->pipebufs; page_cache_get(page); buf->page = page; buf->offset = offset; buf->len = count; cs->pipebufs++; cs->nr_segs++; cs->len = 0; return 0; } /* * Copy a page in the request to/from the userspace buffer. Must be * done atomically */ static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, unsigned offset, unsigned count, int zeroing) { int err; struct page *page = *pagep; if (page && zeroing && count < PAGE_SIZE) { void *mapaddr = kmap_atomic(page, KM_USER1); memset(mapaddr, 0, PAGE_SIZE); kunmap_atomic(mapaddr, KM_USER1); } while (count) { if (cs->write && cs->pipebufs && page) { return fuse_ref_page(cs, page, offset, count); } else if (!cs->len) { if (cs->move_pages && page && offset == 0 && count == PAGE_SIZE) { err = fuse_try_move_page(cs, pagep); if (err <= 0) return err; } else { err = fuse_copy_fill(cs); if (err) return err; } } if (page) { void *mapaddr = kmap_atomic(page, KM_USER1); void *buf = mapaddr + offset; offset += fuse_copy_do(cs, &buf, &count); kunmap_atomic(mapaddr, KM_USER1); } else offset += fuse_copy_do(cs, NULL, &count); } if (page && !cs->write) flush_dcache_page(page); return 0; } /* Copy pages in the request to/from userspace buffer */ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, int zeroing) { unsigned i; struct fuse_req *req = cs->req; unsigned offset = req->page_offset; unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset); for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { int err; err = fuse_copy_page(cs, &req->pages[i], offset, count, zeroing); if (err) return err; nbytes -= count; count = min(nbytes, (unsigned) PAGE_SIZE); offset = 0; } return 0; } /* Copy a single argument in the request to/from userspace buffer */ static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) { while (size) { if (!cs->len) { int err = fuse_copy_fill(cs); if (err) return err; } fuse_copy_do(cs, &val, &size); } return 0; } /* Copy request arguments to/from userspace buffer */ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, unsigned argpages, struct fuse_arg *args, int zeroing) { int err = 0; unsigned i; for (i = 0; !err && i < numargs; i++) { struct fuse_arg *arg = &args[i]; if (i == numargs - 1 && argpages) err = fuse_copy_pages(cs, arg->size, zeroing); else err = fuse_copy_one(cs, arg->value, arg->size); } return err; } static int request_pending(struct fuse_conn *fc) { return !list_empty(&fc->pending) || !list_empty(&fc->interrupts); } /* Wait until a request is available on the pending list */ static void request_wait(struct fuse_conn *fc) __releases(&fc->lock) __acquires(&fc->lock) { DECLARE_WAITQUEUE(wait, current); add_wait_queue_exclusive(&fc->waitq, &wait); while (fc->connected && !request_pending(fc)) { set_current_state(TASK_INTERRUPTIBLE); if (signal_pending(current)) break; spin_unlock(&fc->lock); schedule(); spin_lock(&fc->lock); } set_current_state(TASK_RUNNING); remove_wait_queue(&fc->waitq, &wait); } /* * Transfer an interrupt request to userspace * * Unlike other requests this is assembled on demand, without a need * to allocate a separate fuse_req structure. * * Called with fc->lock held, releases it */ static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs, size_t nbytes, struct fuse_req *req) __releases(&fc->lock) { struct fuse_in_header ih; struct fuse_interrupt_in arg; unsigned reqsize = sizeof(ih) + sizeof(arg); int err; list_del_init(&req->intr_entry); req->intr_unique = fuse_get_unique(fc); memset(&ih, 0, sizeof(ih)); memset(&arg, 0, sizeof(arg)); ih.len = reqsize; ih.opcode = FUSE_INTERRUPT; ih.unique = req->intr_unique; arg.unique = req->in.h.unique; spin_unlock(&fc->lock); if (nbytes < reqsize) return -EINVAL; err = fuse_copy_one(cs, &ih, sizeof(ih)); if (!err) err = fuse_copy_one(cs, &arg, sizeof(arg)); fuse_copy_finish(cs); return err ? err : reqsize; } /* * Read a single request into the userspace filesystem's buffer. This * function waits until a request is available, then removes it from * the pending list and copies request data to userspace buffer. If * no reply is needed (FORGET) or request has been aborted or there * was an error during the copying then it's finished by calling * request_end(). Otherwise add it to the processing list, and set * the 'sent' flag. */ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file, struct fuse_copy_state *cs, size_t nbytes) { int err; struct fuse_req *req; struct fuse_in *in; unsigned reqsize; restart: spin_lock(&fc->lock); err = -EAGAIN; if ((file->f_flags & O_NONBLOCK) && fc->connected && !request_pending(fc)) goto err_unlock; request_wait(fc); err = -ENODEV; if (!fc->connected) goto err_unlock; err = -ERESTARTSYS; if (!request_pending(fc)) goto err_unlock; if (!list_empty(&fc->interrupts)) { req = list_entry(fc->interrupts.next, struct fuse_req, intr_entry); return fuse_read_interrupt(fc, cs, nbytes, req); } req = list_entry(fc->pending.next, struct fuse_req, list); req->state = FUSE_REQ_READING; list_move(&req->list, &fc->io); in = &req->in; reqsize = in->h.len; /* If request is too large, reply with an error and restart the read */ if (nbytes < reqsize) { req->out.h.error = -EIO; /* SETXATTR is special, since it may contain too large data */ if (in->h.opcode == FUSE_SETXATTR) req->out.h.error = -E2BIG; request_end(fc, req); goto restart; } spin_unlock(&fc->lock); cs->req = req; err = fuse_copy_one(cs, &in->h, sizeof(in->h)); if (!err) err = fuse_copy_args(cs, in->numargs, in->argpages, (struct fuse_arg *) in->args, 0); fuse_copy_finish(cs); spin_lock(&fc->lock); req->locked = 0; if (req->aborted) { request_end(fc, req); return -ENODEV; } if (err) { req->out.h.error = -EIO; request_end(fc, req); return err; } if (!req->isreply) request_end(fc, req); else { req->state = FUSE_REQ_SENT; list_move_tail(&req->list, &fc->processing); if (req->interrupted) queue_interrupt(fc, req); spin_unlock(&fc->lock); } return reqsize; err_unlock: spin_unlock(&fc->lock); return err; } static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct fuse_copy_state cs; struct file *file = iocb->ki_filp; struct fuse_conn *fc = fuse_get_conn(file); if (!fc) return -EPERM; fuse_copy_init(&cs, fc, 1, iov, nr_segs); return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs)); } static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { return 1; } static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = fuse_dev_pipe_buf_steal, .get = generic_pipe_buf_get, }; static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { int ret; int page_nr = 0; int do_wakeup = 0; struct pipe_buffer *bufs; struct fuse_copy_state cs; struct fuse_conn *fc = fuse_get_conn(in); if (!fc) return -EPERM; bufs = kmalloc(pipe->buffers * sizeof (struct pipe_buffer), GFP_KERNEL); if (!bufs) return -ENOMEM; fuse_copy_init(&cs, fc, 1, NULL, 0); cs.pipebufs = bufs; cs.pipe = pipe; ret = fuse_dev_do_read(fc, in, &cs, len); if (ret < 0) goto out; ret = 0; pipe_lock(pipe); if (!pipe->readers) { send_sig(SIGPIPE, current, 0); if (!ret) ret = -EPIPE; goto out_unlock; } if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { ret = -EIO; goto out_unlock; } while (page_nr < cs.nr_segs) { int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); struct pipe_buffer *buf = pipe->bufs + newbuf; buf->page = bufs[page_nr].page; buf->offset = bufs[page_nr].offset; buf->len = bufs[page_nr].len; buf->ops = &fuse_dev_pipe_buf_ops; pipe->nrbufs++; page_nr++; ret += buf->len; if (pipe->inode) do_wakeup = 1; } out_unlock: pipe_unlock(pipe); if (do_wakeup) { smp_mb(); if (waitqueue_active(&pipe->wait)) wake_up_interruptible(&pipe->wait); kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); } out: for (; page_nr < cs.nr_segs; page_nr++) page_cache_release(bufs[page_nr].page); kfree(bufs); return ret; } static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, struct fuse_copy_state *cs) { struct fuse_notify_poll_wakeup_out outarg; int err = -EINVAL; if (size != sizeof(outarg)) goto err; err = fuse_copy_one(cs, &outarg, sizeof(outarg)); if (err) goto err; fuse_copy_finish(cs); return fuse_notify_poll_wakeup(fc, &outarg); err: fuse_copy_finish(cs); return err; } static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, struct fuse_copy_state *cs) { struct fuse_notify_inval_inode_out outarg; int err = -EINVAL; if (size != sizeof(outarg)) goto err; err = fuse_copy_one(cs, &outarg, sizeof(outarg)); if (err) goto err; fuse_copy_finish(cs); down_read(&fc->killsb); err = -ENOENT; if (fc->sb) { err = fuse_reverse_inval_inode(fc->sb, outarg.ino, outarg.off, outarg.len); } up_read(&fc->killsb); return err; err: fuse_copy_finish(cs); return err; } static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, struct fuse_copy_state *cs) { struct fuse_notify_inval_entry_out outarg; int err = -ENOMEM; char *buf; struct qstr name; buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); if (!buf) goto err; err = -EINVAL; if (size < sizeof(outarg)) goto err; err = fuse_copy_one(cs, &outarg, sizeof(outarg)); if (err) goto err; err = -ENAMETOOLONG; if (outarg.namelen > FUSE_NAME_MAX) goto err; name.name = buf; name.len = outarg.namelen; err = fuse_copy_one(cs, buf, outarg.namelen + 1); if (err) goto err; fuse_copy_finish(cs); buf[outarg.namelen] = 0; name.hash = full_name_hash(name.name, name.len); down_read(&fc->killsb); err = -ENOENT; if (fc->sb) err = fuse_reverse_inval_entry(fc->sb, outarg.parent, &name); up_read(&fc->killsb); kfree(buf); return err; err: kfree(buf); fuse_copy_finish(cs); return err; } static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, unsigned int size, struct fuse_copy_state *cs) { switch (code) { case FUSE_NOTIFY_POLL: return fuse_notify_poll(fc, size, cs); case FUSE_NOTIFY_INVAL_INODE: return fuse_notify_inval_inode(fc, size, cs); case FUSE_NOTIFY_INVAL_ENTRY: return fuse_notify_inval_entry(fc, size, cs); default: fuse_copy_finish(cs); return -EINVAL; } } /* Look up request on processing list by unique ID */ static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) { struct list_head *entry; list_for_each(entry, &fc->processing) { struct fuse_req *req; req = list_entry(entry, struct fuse_req, list); if (req->in.h.unique == unique || req->intr_unique == unique) return req; } return NULL; } static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, unsigned nbytes) { unsigned reqsize = sizeof(struct fuse_out_header); if (out->h.error) return nbytes != reqsize ? -EINVAL : 0; reqsize += len_args(out->numargs, out->args); if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) return -EINVAL; else if (reqsize > nbytes) { struct fuse_arg *lastarg = &out->args[out->numargs-1]; unsigned diffsize = reqsize - nbytes; if (diffsize > lastarg->size) return -EINVAL; lastarg->size -= diffsize; } return fuse_copy_args(cs, out->numargs, out->argpages, out->args, out->page_zeroing); } /* * Write a single reply to a request. First the header is copied from * the write buffer. The request is then searched on the processing * list by the unique ID found in the header. If found, then remove * it from the list and copy the rest of the buffer to the request. * The request is finished by calling request_end() */ static ssize_t fuse_dev_do_write(struct fuse_conn *fc, struct fuse_copy_state *cs, size_t nbytes) { int err; struct fuse_req *req; struct fuse_out_header oh; if (nbytes < sizeof(struct fuse_out_header)) return -EINVAL; err = fuse_copy_one(cs, &oh, sizeof(oh)); if (err) goto err_finish; err = -EINVAL; if (oh.len != nbytes) goto err_finish; /* * Zero oh.unique indicates unsolicited notification message * and error contains notification code. */ if (!oh.unique) { err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); return err ? err : nbytes; } err = -EINVAL; if (oh.error <= -1000 || oh.error > 0) goto err_finish; spin_lock(&fc->lock); err = -ENOENT; if (!fc->connected) goto err_unlock; req = request_find(fc, oh.unique); if (!req) goto err_unlock; if (req->aborted) { spin_unlock(&fc->lock); fuse_copy_finish(cs); spin_lock(&fc->lock); request_end(fc, req); return -ENOENT; } /* Is it an interrupt reply? */ if (req->intr_unique == oh.unique) { err = -EINVAL; if (nbytes != sizeof(struct fuse_out_header)) goto err_unlock; if (oh.error == -ENOSYS) fc->no_interrupt = 1; else if (oh.error == -EAGAIN) queue_interrupt(fc, req); spin_unlock(&fc->lock); fuse_copy_finish(cs); return nbytes; } req->state = FUSE_REQ_WRITING; list_move(&req->list, &fc->io); req->out.h = oh; req->locked = 1; cs->req = req; if (!req->out.page_replace) cs->move_pages = 0; spin_unlock(&fc->lock); err = copy_out_args(cs, &req->out, nbytes); fuse_copy_finish(cs); spin_lock(&fc->lock); req->locked = 0; if (!err) { if (req->aborted) err = -ENOENT; } else if (!req->aborted) req->out.h.error = -EIO; request_end(fc, req); return err ? err : nbytes; err_unlock: spin_unlock(&fc->lock); err_finish: fuse_copy_finish(cs); return err; } static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct fuse_copy_state cs; struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp); if (!fc) return -EPERM; fuse_copy_init(&cs, fc, 0, iov, nr_segs); return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs)); } static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags) { unsigned nbuf; unsigned idx; struct pipe_buffer *bufs; struct fuse_copy_state cs; struct fuse_conn *fc; size_t rem; ssize_t ret; fc = fuse_get_conn(out); if (!fc) return -EPERM; bufs = kmalloc(pipe->buffers * sizeof (struct pipe_buffer), GFP_KERNEL); if (!bufs) return -ENOMEM; pipe_lock(pipe); nbuf = 0; rem = 0; for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; ret = -EINVAL; if (rem < len) { pipe_unlock(pipe); goto out; } rem = len; while (rem) { struct pipe_buffer *ibuf; struct pipe_buffer *obuf; BUG_ON(nbuf >= pipe->buffers); BUG_ON(!pipe->nrbufs); ibuf = &pipe->bufs[pipe->curbuf]; obuf = &bufs[nbuf]; if (rem >= ibuf->len) { *obuf = *ibuf; ibuf->ops = NULL; pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); pipe->nrbufs--; } else { ibuf->ops->get(pipe, ibuf); *obuf = *ibuf; obuf->flags &= ~PIPE_BUF_FLAG_GIFT; obuf->len = rem; ibuf->offset += obuf->len; ibuf->len -= obuf->len; } nbuf++; rem -= obuf->len; } pipe_unlock(pipe); fuse_copy_init(&cs, fc, 0, NULL, nbuf); cs.pipebufs = bufs; cs.pipe = pipe; if (flags & SPLICE_F_MOVE) cs.move_pages = 1; ret = fuse_dev_do_write(fc, &cs, len); for (idx = 0; idx < nbuf; idx++) { struct pipe_buffer *buf = &bufs[idx]; buf->ops->release(pipe, buf); } out: kfree(bufs); return ret; } static unsigned fuse_dev_poll(struct file *file, poll_table *wait) { unsigned mask = POLLOUT | POLLWRNORM; struct fuse_conn *fc = fuse_get_conn(file); if (!fc) return POLLERR; poll_wait(file, &fc->waitq, wait); spin_lock(&fc->lock); if (!fc->connected) mask = POLLERR; else if (request_pending(fc)) mask |= POLLIN | POLLRDNORM; spin_unlock(&fc->lock); return mask; } /* * Abort all requests on the given list (pending or processing) * * This function releases and reacquires fc->lock */ static void end_requests(struct fuse_conn *fc, struct list_head *head) __releases(&fc->lock) __acquires(&fc->lock) { while (!list_empty(head)) { struct fuse_req *req; req = list_entry(head->next, struct fuse_req, list); req->out.h.error = -ECONNABORTED; request_end(fc, req); spin_lock(&fc->lock); } } /* * Abort requests under I/O * * The requests are set to aborted and finished, and the request * waiter is woken up. This will make request_wait_answer() wait * until the request is unlocked and then return. * * If the request is asynchronous, then the end function needs to be * called after waiting for the request to be unlocked (if it was * locked). */ static void end_io_requests(struct fuse_conn *fc) __releases(&fc->lock) __acquires(&fc->lock) { while (!list_empty(&fc->io)) { struct fuse_req *req = list_entry(fc->io.next, struct fuse_req, list); void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; req->aborted = 1; req->out.h.error = -ECONNABORTED; req->state = FUSE_REQ_FINISHED; list_del_init(&req->list); wake_up(&req->waitq); if (end) { req->end = NULL; __fuse_get_request(req); spin_unlock(&fc->lock); wait_event(req->waitq, !req->locked); end(fc, req); fuse_put_request(fc, req); spin_lock(&fc->lock); } } } /* * Abort all requests. * * Emergency exit in case of a malicious or accidental deadlock, or * just a hung filesystem. * * The same effect is usually achievable through killing the * filesystem daemon and all users of the filesystem. The exception * is the combination of an asynchronous request and the tricky * deadlock (see Documentation/filesystems/fuse.txt). * * During the aborting, progression of requests from the pending and * processing lists onto the io list, and progression of new requests * onto the pending list is prevented by req->connected being false. * * Progression of requests under I/O to the processing list is * prevented by the req->aborted flag being true for these requests. * For this reason requests on the io list must be aborted first. */ void fuse_abort_conn(struct fuse_conn *fc) { spin_lock(&fc->lock); if (fc->connected) { fc->connected = 0; fc->blocked = 0; end_io_requests(fc); end_requests(fc, &fc->pending); end_requests(fc, &fc->processing); wake_up_all(&fc->waitq); wake_up_all(&fc->blocked_waitq); kill_fasync(&fc->fasync, SIGIO, POLL_IN); } spin_unlock(&fc->lock); } EXPORT_SYMBOL_GPL(fuse_abort_conn); int fuse_dev_release(struct inode *inode, struct file *file) { struct fuse_conn *fc = fuse_get_conn(file); if (fc) { spin_lock(&fc->lock); fc->connected = 0; end_requests(fc, &fc->pending); end_requests(fc, &fc->processing); spin_unlock(&fc->lock); fuse_conn_put(fc); } return 0; } EXPORT_SYMBOL_GPL(fuse_dev_release); static int fuse_dev_fasync(int fd, struct file *file, int on) { struct fuse_conn *fc = fuse_get_conn(file); if (!fc) return -EPERM; /* No locking - fasync_helper does its own locking */ return fasync_helper(fd, file, on, &fc->fasync); } const struct file_operations fuse_dev_operations = { .owner = THIS_MODULE, .llseek = no_llseek, .read = do_sync_read, .aio_read = fuse_dev_read, .splice_read = fuse_dev_splice_read, .write = do_sync_write, .aio_write = fuse_dev_write, .splice_write = fuse_dev_splice_write, .poll = fuse_dev_poll, .release = fuse_dev_release, .fasync = fuse_dev_fasync, }; EXPORT_SYMBOL_GPL(fuse_dev_operations); static struct miscdevice fuse_miscdevice = { .minor = FUSE_MINOR, .name = "fuse", .fops = &fuse_dev_operations, }; int __init fuse_dev_init(void) { int err = -ENOMEM; fuse_req_cachep = kmem_cache_create("fuse_request", sizeof(struct fuse_req), 0, 0, NULL); if (!fuse_req_cachep) goto out; err = misc_register(&fuse_miscdevice); if (err) goto out_cache_clean; return 0; out_cache_clean: kmem_cache_destroy(fuse_req_cachep); out: return err; } void fuse_dev_cleanup(void) { misc_deregister(&fuse_miscdevice); kmem_cache_destroy(fuse_req_cachep); }