| /* |
| 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> |
| |
| MODULE_ALIAS_MISCDEV(FUSE_MINOR); |
| |
| 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; |
| } |
| |
| 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); |
| } |
| |
| /* |
| * 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); |
| } |
| } |
| |
| 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 < FUSE_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 == FUSE_MAX_BACKGROUND) { |
| fc->blocked = 0; |
| wake_up_all(&fc->blocked_waitq); |
| } |
| if (fc->num_background == FUSE_CONGESTION_THRESHOLD) { |
| clear_bdi_congested(&fc->bdi, READ); |
| clear_bdi_congested(&fc->bdi, WRITE); |
| } |
| 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); |
| } |
| |
| 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 == FUSE_MAX_BACKGROUND) |
| fc->blocked = 1; |
| if (fc->num_background == FUSE_CONGESTION_THRESHOLD) { |
| set_bdi_congested(&fc->bdi, READ); |
| set_bdi_congested(&fc->bdi, WRITE); |
| } |
| 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); |
| } |
| |
| /* |
| * 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; |
| unsigned long nr_segs; |
| unsigned long seglen; |
| unsigned long addr; |
| struct page *pg; |
| void *mapaddr; |
| void *buf; |
| unsigned len; |
| }; |
| |
| static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc, |
| int write, struct fuse_req *req, |
| const struct iovec *iov, unsigned long nr_segs) |
| { |
| memset(cs, 0, sizeof(*cs)); |
| cs->fc = fc; |
| cs->write = write; |
| cs->req = req; |
| 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->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->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--; |
| } |
| down_read(¤t->mm->mmap_sem); |
| err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0, |
| &cs->pg, NULL); |
| up_read(¤t->mm->mmap_sem); |
| 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; |
| } |
| |
| /* |
| * 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 *page, |
| unsigned offset, unsigned count, int zeroing) |
| { |
| 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->len) { |
| int 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++) { |
| struct page *page = req->pages[i]; |
| int err = fuse_copy_page(cs, page, 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_req *req, |
| const struct iovec *iov, unsigned long nr_segs) |
| __releases(&fc->lock) |
| { |
| struct fuse_copy_state cs; |
| 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 (iov_length(iov, nr_segs) < reqsize) |
| return -EINVAL; |
| |
| fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs); |
| 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_read(struct kiocb *iocb, const struct iovec *iov, |
| unsigned long nr_segs, loff_t pos) |
| { |
| int err; |
| struct fuse_req *req; |
| struct fuse_in *in; |
| struct fuse_copy_state cs; |
| unsigned reqsize; |
| struct file *file = iocb->ki_filp; |
| struct fuse_conn *fc = fuse_get_conn(file); |
| if (!fc) |
| return -EPERM; |
| |
| 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, req, iov, nr_segs); |
| } |
| |
| 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 (iov_length(iov, nr_segs) < 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); |
| fuse_copy_init(&cs, fc, 1, req, iov, nr_segs); |
| 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 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; |
| |
| if (size != sizeof(outarg)) |
| return -EINVAL; |
| |
| err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| if (err) |
| return err; |
| |
| return fuse_notify_poll_wakeup(fc, &outarg); |
| } |
| |
| 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); |
| |
| default: |
| 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_write(struct kiocb *iocb, const struct iovec *iov, |
| unsigned long nr_segs, loff_t pos) |
| { |
| int err; |
| unsigned nbytes = iov_length(iov, nr_segs); |
| struct fuse_req *req; |
| struct fuse_out_header oh; |
| 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, NULL, iov, nr_segs); |
| 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); |
| fuse_copy_finish(&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; |
| 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 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); |
| } |
| |
| static 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; |
| } |
| |
| 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, |
| .write = do_sync_write, |
| .aio_write = fuse_dev_write, |
| .poll = fuse_dev_poll, |
| .release = fuse_dev_release, |
| .fasync = fuse_dev_fasync, |
| }; |
| |
| 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); |
| } |