diff options
Diffstat (limited to 'kernel/fs/fuse/dev.c')
| -rw-r--r-- | kernel/fs/fuse/dev.c | 2273 |
1 files changed, 2273 insertions, 0 deletions
diff --git a/kernel/fs/fuse/dev.c b/kernel/fs/fuse/dev.c new file mode 100644 index 000000000..c8b68ab2e --- /dev/null +++ b/kernel/fs/fuse/dev.c @@ -0,0 +1,2273 @@ +/* + 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; + struct iov_iter *iter; + struct pipe_buffer *pipebufs; + struct pipe_buffer *currbuf; + struct pipe_inode_info *pipe; + unsigned long nr_segs; + 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, + struct iov_iter *iter) +{ + memset(cs, 0, sizeof(*cs)); + cs->fc = fc; + cs->write = write; + cs->iter = iter; +} + +/* 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 { + size_t off; + err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); + if (err < 0) + return err; + BUG_ON(!err); + cs->len = err; + cs->offset = off; + cs->pg = page; + cs->offset = off; + iov_iter_advance(cs->iter, err); + } + + 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 (!PageUptodate(newpage)) + SetPageUptodate(newpage); + + 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 int fuse_dev_open(struct inode *inode, struct file *file) +{ + /* + * The fuse device's file's private_data is used to hold + * the fuse_conn(ection) when it is mounted, and is used to + * keep track of whether the file has been mounted already. + */ + file->private_data = NULL; + return 0; +} + +static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) +{ + struct fuse_copy_state cs; + struct file *file = iocb->ki_filp; + struct fuse_conn *fc = fuse_get_conn(file); + if (!fc) + return -EPERM; + + if (!iter_is_iovec(to)) + return -EINVAL; + + fuse_copy_init(&cs, fc, 1, to); + + return fuse_dev_do_read(fc, file, &cs, iov_iter_count(to)); +} + +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); + 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) +{ + /* Don't try to move pages (yet) */ + cs->move_pages = 0; + + 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, struct iov_iter *from) +{ + struct fuse_copy_state cs; + struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp); + if (!fc) + return -EPERM; + + if (!iter_is_iovec(from)) + return -EINVAL; + + fuse_copy_init(&cs, fc, 0, from); + + return fuse_dev_do_write(fc, &cs, iov_iter_count(from)); +} + +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); + cs.pipebufs = bufs; + cs.nr_segs = nbuf; + 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, + .open = fuse_dev_open, + .llseek = no_llseek, + .read_iter = fuse_dev_read, + .splice_read = fuse_dev_splice_read, + .write_iter = 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); +} |