| /* |
| 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, struct page **pages, |
| struct fuse_page_desc *page_descs, |
| unsigned npages) |
| { |
| memset(req, 0, sizeof(*req)); |
| memset(pages, 0, sizeof(*pages) * npages); |
| memset(page_descs, 0, sizeof(*page_descs) * npages); |
| INIT_LIST_HEAD(&req->list); |
| INIT_LIST_HEAD(&req->intr_entry); |
| init_waitqueue_head(&req->waitq); |
| atomic_set(&req->count, 1); |
| req->pages = pages; |
| req->page_descs = page_descs; |
| req->max_pages = npages; |
| } |
| |
| static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) |
| { |
| struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags); |
| if (req) { |
| struct page **pages; |
| struct fuse_page_desc *page_descs; |
| |
| if (npages <= FUSE_REQ_INLINE_PAGES) { |
| pages = req->inline_pages; |
| page_descs = req->inline_page_descs; |
| } else { |
| pages = kmalloc(sizeof(struct page *) * npages, flags); |
| page_descs = kmalloc(sizeof(struct fuse_page_desc) * |
| npages, flags); |
| } |
| |
| if (!pages || !page_descs) { |
| kfree(pages); |
| kfree(page_descs); |
| kmem_cache_free(fuse_req_cachep, req); |
| return NULL; |
| } |
| |
| fuse_request_init(req, pages, page_descs, npages); |
| } |
| return req; |
| } |
| |
| struct fuse_req *fuse_request_alloc(unsigned npages) |
| { |
| return __fuse_request_alloc(npages, GFP_KERNEL); |
| } |
| EXPORT_SYMBOL_GPL(fuse_request_alloc); |
| |
| struct fuse_req *fuse_request_alloc_nofs(unsigned npages) |
| { |
| return __fuse_request_alloc(npages, GFP_NOFS); |
| } |
| |
| void fuse_request_free(struct fuse_req *req) |
| { |
| if (req->pages != req->inline_pages) { |
| kfree(req->pages); |
| kfree(req->page_descs); |
| } |
| 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); |
| } |
| |
| 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 = from_kuid_munged(&init_user_ns, current_fsuid()); |
| req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid()); |
| req->in.h.pid = current->pid; |
| } |
| |
| void fuse_set_initialized(struct fuse_conn *fc) |
| { |
| /* Make sure stores before this are seen on another CPU */ |
| smp_wmb(); |
| fc->initialized = 1; |
| } |
| |
| static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) |
| { |
| return !fc->initialized || (for_background && fc->blocked); |
| } |
| |
| static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, |
| bool for_background) |
| { |
| struct fuse_req *req; |
| int err; |
| atomic_inc(&fc->num_waiting); |
| |
| if (fuse_block_alloc(fc, for_background)) { |
| sigset_t oldset; |
| int intr; |
| |
| block_sigs(&oldset); |
| intr = wait_event_interruptible_exclusive(fc->blocked_waitq, |
| !fuse_block_alloc(fc, for_background)); |
| restore_sigs(&oldset); |
| err = -EINTR; |
| if (intr) |
| goto out; |
| } |
| /* Matches smp_wmb() in fuse_set_initialized() */ |
| smp_rmb(); |
| |
| err = -ENOTCONN; |
| if (!fc->connected) |
| goto out; |
| |
| req = fuse_request_alloc(npages); |
| err = -ENOMEM; |
| if (!req) { |
| if (for_background) |
| wake_up(&fc->blocked_waitq); |
| goto out; |
| } |
| |
| fuse_req_init_context(req); |
| req->waiting = 1; |
| req->background = for_background; |
| return req; |
| |
| out: |
| atomic_dec(&fc->num_waiting); |
| return ERR_PTR(err); |
| } |
| |
| struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages) |
| { |
| return __fuse_get_req(fc, npages, false); |
| } |
| EXPORT_SYMBOL_GPL(fuse_get_req); |
| |
| struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc, |
| unsigned npages) |
| { |
| return __fuse_get_req(fc, npages, true); |
| } |
| EXPORT_SYMBOL_GPL(fuse_get_req_for_background); |
| |
| /* |
| * 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; |
| req->stolen_file = get_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, req->pages, req->page_descs, req->max_pages); |
| 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_nopages(struct fuse_conn *fc, |
| struct file *file) |
| { |
| struct fuse_req *req; |
| |
| atomic_inc(&fc->num_waiting); |
| wait_event(fc->blocked_waitq, fc->initialized); |
| /* Matches smp_wmb() in fuse_set_initialized() */ |
| smp_rmb(); |
| req = fuse_request_alloc(0); |
| if (!req) |
| req = get_reserved_req(fc, file); |
| |
| fuse_req_init_context(req); |
| req->waiting = 1; |
| req->background = 0; |
| return req; |
| } |
| |
| void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) |
| { |
| if (atomic_dec_and_test(&req->count)) { |
| if (unlikely(req->background)) { |
| /* |
| * We get here in the unlikely case that a background |
| * request was allocated but not sent |
| */ |
| spin_lock(&fc->lock); |
| if (!fc->blocked) |
| wake_up(&fc->blocked_waitq); |
| spin_unlock(&fc->lock); |
| } |
| |
| 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.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); |
| } |
| |
| void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, |
| u64 nodeid, u64 nlookup) |
| { |
| forget->forget_one.nodeid = nodeid; |
| forget->forget_one.nlookup = nlookup; |
| |
| spin_lock(&fc->lock); |
| if (fc->connected) { |
| fc->forget_list_tail->next = forget; |
| fc->forget_list_tail = forget; |
| wake_up(&fc->waitq); |
| kill_fasync(&fc->fasync, SIGIO, POLL_IN); |
| } else { |
| kfree(forget); |
| } |
| spin_unlock(&fc->lock); |
| } |
| |
| 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++; |
| req->in.h.unique = fuse_get_unique(fc); |
| 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) { |
| req->background = 0; |
| |
| if (fc->num_background == fc->max_background) |
| fc->blocked = 0; |
| |
| /* Wake up next waiter, if any */ |
| if (!fc->blocked && waitqueue_active(&fc->blocked_waitq)) |
| wake_up(&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); |
| } |
| } |
| |
| static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) |
| { |
| BUG_ON(req->background); |
| spin_lock(&fc->lock); |
| if (!fc->connected) |
| req->out.h.error = -ENOTCONN; |
| else if (fc->conn_error) |
| req->out.h.error = -ECONNREFUSED; |
| else { |
| req->in.h.unique = fuse_get_unique(fc); |
| 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); |
| } |
| |
| void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) |
| { |
| req->isreply = 1; |
| __fuse_request_send(fc, req); |
| } |
| EXPORT_SYMBOL_GPL(fuse_request_send); |
| |
| static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) |
| { |
| if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS) |
| args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE; |
| |
| if (fc->minor < 9) { |
| switch (args->in.h.opcode) { |
| case FUSE_LOOKUP: |
| case FUSE_CREATE: |
| case FUSE_MKNOD: |
| case FUSE_MKDIR: |
| case FUSE_SYMLINK: |
| case FUSE_LINK: |
| args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; |
| break; |
| case FUSE_GETATTR: |
| case FUSE_SETATTR: |
| args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; |
| break; |
| } |
| } |
| if (fc->minor < 12) { |
| switch (args->in.h.opcode) { |
| case FUSE_CREATE: |
| args->in.args[0].size = sizeof(struct fuse_open_in); |
| break; |
| case FUSE_MKNOD: |
| args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; |
| break; |
| } |
| } |
| } |
| |
| ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) |
| { |
| struct fuse_req *req; |
| ssize_t ret; |
| |
| req = fuse_get_req(fc, 0); |
| if (IS_ERR(req)) |
| return PTR_ERR(req); |
| |
| /* Needs to be done after fuse_get_req() so that fc->minor is valid */ |
| fuse_adjust_compat(fc, args); |
| |
| req->in.h.opcode = args->in.h.opcode; |
| req->in.h.nodeid = args->in.h.nodeid; |
| req->in.numargs = args->in.numargs; |
| memcpy(req->in.args, args->in.args, |
| args->in.numargs * sizeof(struct fuse_in_arg)); |
| req->out.argvar = args->out.argvar; |
| req->out.numargs = args->out.numargs; |
| memcpy(req->out.args, args->out.args, |
| args->out.numargs * sizeof(struct fuse_arg)); |
| fuse_request_send(fc, req); |
| ret = req->out.h.error; |
| if (!ret && args->out.argvar) { |
| BUG_ON(args->out.numargs != 1); |
| ret = req->out.args[0].size; |
| } |
| fuse_put_request(fc, req); |
| |
| return ret; |
| } |
| |
| static void fuse_request_send_nowait_locked(struct fuse_conn *fc, |
| struct fuse_req *req) |
| { |
| BUG_ON(!req->background); |
| 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_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); |
| |
| static int fuse_request_send_notify_reply(struct fuse_conn *fc, |
| struct fuse_req *req, u64 unique) |
| { |
| int err = -ENODEV; |
| |
| req->isreply = 0; |
| req->in.h.unique = unique; |
| spin_lock(&fc->lock); |
| if (fc->connected) { |
| queue_request(fc, req); |
| err = 0; |
| } |
| spin_unlock(&fc->lock); |
| |
| return err; |
| } |
| |
| /* |
| * 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); |
| } |
| |
| void fuse_force_forget(struct file *file, u64 nodeid) |
| { |
| struct inode *inode = file_inode(file); |
| struct fuse_conn *fc = get_fuse_conn(inode); |
| struct fuse_req *req; |
| struct fuse_forget_in inarg; |
| |
| memset(&inarg, 0, sizeof(inarg)); |
| inarg.nlookup = 1; |
| req = fuse_get_req_nofail_nopages(fc, file); |
| req->in.h.opcode = FUSE_FORGET; |
| req->in.h.nodeid = nodeid; |
| req->in.numargs = 1; |
| req->in.args[0].size = sizeof(inarg); |
| req->in.args[0].value = &inarg; |
| req->isreply = 0; |
| __fuse_request_send(fc, req); |
| /* ignore errors */ |
| fuse_put_request(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; |
| unsigned len; |
| unsigned offset; |
| 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->len = PAGE_SIZE - cs->len; |
| cs->currbuf = NULL; |
| } else if (cs->pg) { |
| if (cs->write) { |
| flush_dcache_page(cs->pg); |
| set_page_dirty_lock(cs->pg); |
| } |
| put_page(cs->pg); |
| } |
| cs->pg = 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) |
| { |
| struct page *page; |
| 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->pg = buf->page; |
| cs->offset = buf->offset; |
| cs->len = buf->len; |
| cs->pipebufs++; |
| cs->nr_segs--; |
| } else { |
| 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->pg = page; |
| cs->offset = 0; |
| 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, &page); |
| if (err < 0) |
| return err; |
| BUG_ON(err != 1); |
| cs->pg = page; |
| cs->offset = cs->addr % PAGE_SIZE; |
| cs->len = min(PAGE_SIZE - cs->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) { |
| void *pgaddr = kmap_atomic(cs->pg); |
| void *buf = pgaddr + cs->offset; |
| |
| if (cs->write) |
| memcpy(buf, *val, ncpy); |
| else |
| memcpy(*val, buf, ncpy); |
| |
| kunmap_atomic(pgaddr); |
| *val += ncpy; |
| } |
| *size -= ncpy; |
| cs->len -= ncpy; |
| cs->offset += 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; |
| |
| 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; |
| |
| /* |
| * 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; |
| |
| err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); |
| if (err) { |
| unlock_page(newpage); |
| return err; |
| } |
| |
| 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->pg = buf->page; |
| cs->offset = 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) |
| clear_highpage(page); |
| |
| 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); |
| void *buf = mapaddr + offset; |
| offset += fuse_copy_do(cs, &buf, &count); |
| kunmap_atomic(mapaddr); |
| } 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; |
| |
| for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { |
| int err; |
| unsigned offset = req->page_descs[i].offset; |
| unsigned count = min(nbytes, req->page_descs[i].length); |
| |
| err = fuse_copy_page(cs, &req->pages[i], offset, count, |
| zeroing); |
| if (err) |
| return err; |
| |
| nbytes -= count; |
| } |
| 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 forget_pending(struct fuse_conn *fc) |
| { |
| return fc->forget_list_head.next != NULL; |
| } |
| |
| static int request_pending(struct fuse_conn *fc) |
| { |
| return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) || |
| forget_pending(fc); |
| } |
| |
| /* 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; |
| } |
| |
| static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc, |
| unsigned max, |
| unsigned *countp) |
| { |
| struct fuse_forget_link *head = fc->forget_list_head.next; |
| struct fuse_forget_link **newhead = &head; |
| unsigned count; |
| |
| for (count = 0; *newhead != NULL && count < max; count++) |
| newhead = &(*newhead)->next; |
| |
| fc->forget_list_head.next = *newhead; |
| *newhead = NULL; |
| if (fc->forget_list_head.next == NULL) |
| fc->forget_list_tail = &fc->forget_list_head; |
| |
| if (countp != NULL) |
| *countp = count; |
| |
| return head; |
| } |
| |
| static int fuse_read_single_forget(struct fuse_conn *fc, |
| struct fuse_copy_state *cs, |
| size_t nbytes) |
| __releases(fc->lock) |
| { |
| int err; |
| struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL); |
| struct fuse_forget_in arg = { |
| .nlookup = forget->forget_one.nlookup, |
| }; |
| struct fuse_in_header ih = { |
| .opcode = FUSE_FORGET, |
| .nodeid = forget->forget_one.nodeid, |
| .unique = fuse_get_unique(fc), |
| .len = sizeof(ih) + sizeof(arg), |
| }; |
| |
| spin_unlock(&fc->lock); |
| kfree(forget); |
| if (nbytes < ih.len) |
| return -EINVAL; |
| |
| err = fuse_copy_one(cs, &ih, sizeof(ih)); |
| if (!err) |
| err = fuse_copy_one(cs, &arg, sizeof(arg)); |
| fuse_copy_finish(cs); |
| |
| if (err) |
| return err; |
| |
| return ih.len; |
| } |
| |
| static int fuse_read_batch_forget(struct fuse_conn *fc, |
| struct fuse_copy_state *cs, size_t nbytes) |
| __releases(fc->lock) |
| { |
| int err; |
| unsigned max_forgets; |
| unsigned count; |
| struct fuse_forget_link *head; |
| struct fuse_batch_forget_in arg = { .count = 0 }; |
| struct fuse_in_header ih = { |
| .opcode = FUSE_BATCH_FORGET, |
| .unique = fuse_get_unique(fc), |
| .len = sizeof(ih) + sizeof(arg), |
| }; |
| |
| if (nbytes < ih.len) { |
| spin_unlock(&fc->lock); |
| return -EINVAL; |
| } |
| |
| max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); |
| head = dequeue_forget(fc, max_forgets, &count); |
| spin_unlock(&fc->lock); |
| |
| arg.count = count; |
| ih.len += count * sizeof(struct fuse_forget_one); |
| err = fuse_copy_one(cs, &ih, sizeof(ih)); |
| if (!err) |
| err = fuse_copy_one(cs, &arg, sizeof(arg)); |
| |
| while (head) { |
| struct fuse_forget_link *forget = head; |
| |
| if (!err) { |
| err = fuse_copy_one(cs, &forget->forget_one, |
| sizeof(forget->forget_one)); |
| } |
| head = forget->next; |
| kfree(forget); |
| } |
| |
| fuse_copy_finish(cs); |
| |
| if (err) |
| return err; |
| |
| return ih.len; |
| } |
| |
| static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs, |
| size_t nbytes) |
| __releases(fc->lock) |
| { |
| if (fc->minor < 16 || fc->forget_list_head.next->next == NULL) |
| return fuse_read_single_forget(fc, cs, nbytes); |
| else |
| return fuse_read_batch_forget(fc, cs, nbytes); |
| } |
| |
| /* |
| * 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); |
| } |
| |
| if (forget_pending(fc)) { |
| if (list_empty(&fc->pending) || fc->forget_batch-- > 0) |
| return fuse_read_forget(fc, cs, nbytes); |
| |
| if (fc->forget_batch <= -8) |
| fc->forget_batch = 16; |
| } |
| |
| 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 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; |
| /* |
| * Need to be careful about this. Having buf->ops in module |
| * code can Oops if the buffer persists after module unload. |
| */ |
| buf->ops = &nosteal_pipe_buf_ops; |
| |
| pipe->nrbufs++; |
| page_nr++; |
| ret += buf->len; |
| |
| if (pipe->files) |
| 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; |
| |
| err = -EINVAL; |
| if (size != sizeof(outarg) + outarg.namelen + 1) |
| 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, 0, &name); |
| up_read(&fc->killsb); |
| kfree(buf); |
| return err; |
| |
| err: |
| kfree(buf); |
| fuse_copy_finish(cs); |
| return err; |
| } |
| |
| static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, |
| struct fuse_copy_state *cs) |
| { |
| struct fuse_notify_delete_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; |
| |
| err = -EINVAL; |
| if (size != sizeof(outarg) + outarg.namelen + 1) |
| 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, |
| outarg.child, &name); |
| up_read(&fc->killsb); |
| kfree(buf); |
| return err; |
| |
| err: |
| kfree(buf); |
| fuse_copy_finish(cs); |
| return err; |
| } |
| |
| static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, |
| struct fuse_copy_state *cs) |
| { |
| struct fuse_notify_store_out outarg; |
| struct inode *inode; |
| struct address_space *mapping; |
| u64 nodeid; |
| int err; |
| pgoff_t index; |
| unsigned int offset; |
| unsigned int num; |
| loff_t file_size; |
| loff_t end; |
| |
| err = -EINVAL; |
| if (size < sizeof(outarg)) |
| goto out_finish; |
| |
| err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| if (err) |
| goto out_finish; |
| |
| err = -EINVAL; |
| if (size - sizeof(outarg) != outarg.size) |
| goto out_finish; |
| |
| nodeid = outarg.nodeid; |
| |
| down_read(&fc->killsb); |
| |
| err = -ENOENT; |
| if (!fc->sb) |
| goto out_up_killsb; |
| |
| inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); |
| if (!inode) |
| goto out_up_killsb; |
| |
| mapping = inode->i_mapping; |
| index = outarg.offset >> PAGE_CACHE_SHIFT; |
| offset = outarg.offset & ~PAGE_CACHE_MASK; |
| file_size = i_size_read(inode); |
| end = outarg.offset + outarg.size; |
| if (end > file_size) { |
| file_size = end; |
| fuse_write_update_size(inode, file_size); |
| } |
| |
| num = outarg.size; |
| while (num) { |
| struct page *page; |
| unsigned int this_num; |
| |
| err = -ENOMEM; |
| page = find_or_create_page(mapping, index, |
| mapping_gfp_mask(mapping)); |
| if (!page) |
| goto out_iput; |
| |
| this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset); |
| err = fuse_copy_page(cs, &page, offset, this_num, 0); |
| if (!err && offset == 0 && |
| (this_num == PAGE_CACHE_SIZE || file_size == end)) |
| SetPageUptodate(page); |
| unlock_page(page); |
| page_cache_release(page); |
| |
| if (err) |
| goto out_iput; |
| |
| num -= this_num; |
| offset = 0; |
| index++; |
| } |
| |
| err = 0; |
| |
| out_iput: |
| iput(inode); |
| out_up_killsb: |
| up_read(&fc->killsb); |
| out_finish: |
| fuse_copy_finish(cs); |
| return err; |
| } |
| |
| static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) |
| { |
| release_pages(req->pages, req->num_pages, false); |
| } |
| |
| static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, |
| struct fuse_notify_retrieve_out *outarg) |
| { |
| int err; |
| struct address_space *mapping = inode->i_mapping; |
| struct fuse_req *req; |
| pgoff_t index; |
| loff_t file_size; |
| unsigned int num; |
| unsigned int offset; |
| size_t total_len = 0; |
| int num_pages; |
| |
| offset = outarg->offset & ~PAGE_CACHE_MASK; |
| file_size = i_size_read(inode); |
| |
| num = outarg->size; |
| if (outarg->offset > file_size) |
| num = 0; |
| else if (outarg->offset + num > file_size) |
| num = file_size - outarg->offset; |
| |
| num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ); |
| |
| req = fuse_get_req(fc, num_pages); |
| if (IS_ERR(req)) |
| return PTR_ERR(req); |
| |
| req->in.h.opcode = FUSE_NOTIFY_REPLY; |
| req->in.h.nodeid = outarg->nodeid; |
| req->in.numargs = 2; |
| req->in.argpages = 1; |
| req->page_descs[0].offset = offset; |
| req->end = fuse_retrieve_end; |
| |
| index = outarg->offset >> PAGE_CACHE_SHIFT; |
| |
| while (num && req->num_pages < num_pages) { |
| struct page *page; |
| unsigned int this_num; |
| |
| page = find_get_page(mapping, index); |
| if (!page) |
| break; |
| |
| this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset); |
| req->pages[req->num_pages] = page; |
| req->page_descs[req->num_pages].length = this_num; |
| req->num_pages++; |
| |
| offset = 0; |
| num -= this_num; |
| total_len += this_num; |
| index++; |
| } |
| req->misc.retrieve_in.offset = outarg->offset; |
| req->misc.retrieve_in.size = total_len; |
| req->in.args[0].size = sizeof(req->misc.retrieve_in); |
| req->in.args[0].value = &req->misc.retrieve_in; |
| req->in.args[1].size = total_len; |
| |
| err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); |
| if (err) |
| fuse_retrieve_end(fc, req); |
| |
| return err; |
| } |
| |
| static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, |
| struct fuse_copy_state *cs) |
| { |
| struct fuse_notify_retrieve_out outarg; |
| struct inode *inode; |
| int err; |
| |
| err = -EINVAL; |
| if (size != sizeof(outarg)) |
| goto copy_finish; |
| |
| err = fuse_copy_one(cs, &outarg, sizeof(outarg)); |
| if (err) |
| goto copy_finish; |
| |
| fuse_copy_finish(cs); |
| |
| down_read(&fc->killsb); |
| err = -ENOENT; |
| if (fc->sb) { |
| u64 nodeid = outarg.nodeid; |
| |
| inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); |
| if (inode) { |
| err = fuse_retrieve(fc, inode, &outarg); |
| iput(inode); |
| } |
| } |
| up_read(&fc->killsb); |
| |
| return err; |
| |
| copy_finish: |
| 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); |
| |
| case FUSE_NOTIFY_STORE: |
| return fuse_notify_store(fc, size, cs); |
| |
| case FUSE_NOTIFY_RETRIEVE: |
| return fuse_notify_retrieve(fc, size, cs); |
| |
| case FUSE_NOTIFY_DELETE: |
| return fuse_notify_delete(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 fuse_req *req; |
| |
| list_for_each_entry(req, &fc->processing, 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); |
| } |
| } |
| } |
| |
| static void end_queued_requests(struct fuse_conn *fc) |
| __releases(fc->lock) |
| __acquires(fc->lock) |
| { |
| fc->max_background = UINT_MAX; |
| flush_bg_queue(fc); |
| end_requests(fc, &fc->pending); |
| end_requests(fc, &fc->processing); |
| while (forget_pending(fc)) |
| kfree(dequeue_forget(fc, 1, NULL)); |
| } |
| |
| static void end_polls(struct fuse_conn *fc) |
| { |
| struct rb_node *p; |
| |
| p = rb_first(&fc->polled_files); |
| |
| while (p) { |
| struct fuse_file *ff; |
| ff = rb_entry(p, struct fuse_file, polled_node); |
| wake_up_interruptible_all(&ff->poll_wait); |
| |
| p = rb_next(p); |
| } |
| } |
| |
| /* |
| * 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; |
| fuse_set_initialized(fc); |
| end_io_requests(fc); |
| end_queued_requests(fc); |
| end_polls(fc); |
| 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; |
| fc->blocked = 0; |
| fuse_set_initialized(fc); |
| end_queued_requests(fc); |
| end_polls(fc); |
| wake_up_all(&fc->blocked_waitq); |
| 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); |
| } |