diff options
Diffstat (limited to 'fs/fuse/file.c')
| -rw-r--r-- | fs/fuse/file.c | 2224 |
1 files changed, 2224 insertions, 0 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c new file mode 100644 index 00000000..504e61b7 --- /dev/null +++ b/fs/fuse/file.c @@ -0,0 +1,2224 @@ +/* + 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/pagemap.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/module.h> +#include <linux/compat.h> +#include <linux/swap.h> + +static const struct file_operations fuse_direct_io_file_operations; + +static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file, + int opcode, struct fuse_open_out *outargp) +{ + struct fuse_open_in inarg; + struct fuse_req *req; + int err; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + memset(&inarg, 0, sizeof(inarg)); + inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY); + if (!fc->atomic_o_trunc) + inarg.flags &= ~O_TRUNC; + req->in.h.opcode = opcode; + req->in.h.nodeid = nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + req->out.numargs = 1; + req->out.args[0].size = sizeof(*outargp); + req->out.args[0].value = outargp; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + + return err; +} + +struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) +{ + struct fuse_file *ff; + + ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); + if (unlikely(!ff)) + return NULL; + + ff->fc = fc; + ff->reserved_req = fuse_request_alloc(); + if (unlikely(!ff->reserved_req)) { + kfree(ff); + return NULL; + } + + INIT_LIST_HEAD(&ff->write_entry); + atomic_set(&ff->count, 0); + RB_CLEAR_NODE(&ff->polled_node); + init_waitqueue_head(&ff->poll_wait); + + spin_lock(&fc->lock); + ff->kh = ++fc->khctr; + spin_unlock(&fc->lock); + + return ff; +} + +void fuse_file_free(struct fuse_file *ff) +{ + fuse_request_free(ff->reserved_req); + kfree(ff); +} + +struct fuse_file *fuse_file_get(struct fuse_file *ff) +{ + atomic_inc(&ff->count); + return ff; +} + +static void fuse_release_async(struct work_struct *work) +{ + struct fuse_req *req; + struct fuse_conn *fc; + struct path path; + + req = container_of(work, struct fuse_req, misc.release.work); + path = req->misc.release.path; + fc = get_fuse_conn(path.dentry->d_inode); + + fuse_put_request(fc, req); + path_put(&path); +} + +static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req) +{ + if (fc->destroy_req) { + /* + * If this is a fuseblk mount, then it's possible that + * releasing the path will result in releasing the + * super block and sending the DESTROY request. If + * the server is single threaded, this would hang. + * For this reason do the path_put() in a separate + * thread. + */ + atomic_inc(&req->count); + INIT_WORK(&req->misc.release.work, fuse_release_async); + schedule_work(&req->misc.release.work); + } else { + path_put(&req->misc.release.path); + } +} + +static void fuse_file_put(struct fuse_file *ff, bool sync) +{ + if (atomic_dec_and_test(&ff->count)) { + struct fuse_req *req = ff->reserved_req; + + if (sync) { + fuse_request_send(ff->fc, req); + path_put(&req->misc.release.path); + fuse_put_request(ff->fc, req); + } else { + req->end = fuse_release_end; + fuse_request_send_background(ff->fc, req); + } + kfree(ff); + } +} + +int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, + bool isdir) +{ + struct fuse_open_out outarg; + struct fuse_file *ff; + int err; + int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN; + + ff = fuse_file_alloc(fc); + if (!ff) + return -ENOMEM; + + err = fuse_send_open(fc, nodeid, file, opcode, &outarg); + if (err) { + fuse_file_free(ff); + return err; + } + + if (isdir) + outarg.open_flags &= ~FOPEN_DIRECT_IO; + + ff->fh = outarg.fh; + ff->nodeid = nodeid; + ff->open_flags = outarg.open_flags; + file->private_data = fuse_file_get(ff); + + return 0; +} +EXPORT_SYMBOL_GPL(fuse_do_open); + +void fuse_finish_open(struct inode *inode, struct file *file) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = get_fuse_conn(inode); + + if (ff->open_flags & FOPEN_DIRECT_IO) + file->f_op = &fuse_direct_io_file_operations; + if (!(ff->open_flags & FOPEN_KEEP_CACHE)) + invalidate_inode_pages2(inode->i_mapping); + if (ff->open_flags & FOPEN_NONSEEKABLE) + nonseekable_open(inode, file); + if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) { + struct fuse_inode *fi = get_fuse_inode(inode); + + spin_lock(&fc->lock); + fi->attr_version = ++fc->attr_version; + i_size_write(inode, 0); + spin_unlock(&fc->lock); + fuse_invalidate_attr(inode); + } +} + +int fuse_open_common(struct inode *inode, struct file *file, bool isdir) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + err = generic_file_open(inode, file); + if (err) + return err; + + err = fuse_do_open(fc, get_node_id(inode), file, isdir); + if (err) + return err; + + fuse_finish_open(inode, file); + + return 0; +} + +static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode) +{ + struct fuse_conn *fc = ff->fc; + struct fuse_req *req = ff->reserved_req; + struct fuse_release_in *inarg = &req->misc.release.in; + + spin_lock(&fc->lock); + list_del(&ff->write_entry); + if (!RB_EMPTY_NODE(&ff->polled_node)) + rb_erase(&ff->polled_node, &fc->polled_files); + spin_unlock(&fc->lock); + + wake_up_interruptible_all(&ff->poll_wait); + + inarg->fh = ff->fh; + inarg->flags = flags; + req->in.h.opcode = opcode; + req->in.h.nodeid = ff->nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(struct fuse_release_in); + req->in.args[0].value = inarg; +} + +void fuse_release_common(struct file *file, int opcode) +{ + struct fuse_file *ff; + struct fuse_req *req; + + ff = file->private_data; + if (unlikely(!ff)) + return; + + req = ff->reserved_req; + fuse_prepare_release(ff, file->f_flags, opcode); + + if (ff->flock) { + struct fuse_release_in *inarg = &req->misc.release.in; + inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK; + inarg->lock_owner = fuse_lock_owner_id(ff->fc, + (fl_owner_t) file); + } + /* Hold vfsmount and dentry until release is finished */ + path_get(&file->f_path); + req->misc.release.path = file->f_path; + + /* + * Normally this will send the RELEASE request, however if + * some asynchronous READ or WRITE requests are outstanding, + * the sending will be delayed. + * + * Make the release synchronous if this is a fuseblk mount, + * synchronous RELEASE is allowed (and desirable) in this case + * because the server can be trusted not to screw up. + */ + fuse_file_put(ff, ff->fc->destroy_req != NULL); +} + +static int fuse_open(struct inode *inode, struct file *file) +{ + return fuse_open_common(inode, file, false); +} + +static int fuse_release(struct inode *inode, struct file *file) +{ + fuse_release_common(file, FUSE_RELEASE); + + /* return value is ignored by VFS */ + return 0; +} + +void fuse_sync_release(struct fuse_file *ff, int flags) +{ + WARN_ON(atomic_read(&ff->count) > 1); + fuse_prepare_release(ff, flags, FUSE_RELEASE); + ff->reserved_req->force = 1; + fuse_request_send(ff->fc, ff->reserved_req); + fuse_put_request(ff->fc, ff->reserved_req); + kfree(ff); +} +EXPORT_SYMBOL_GPL(fuse_sync_release); + +/* + * Scramble the ID space with XTEA, so that the value of the files_struct + * pointer is not exposed to userspace. + */ +u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id) +{ + u32 *k = fc->scramble_key; + u64 v = (unsigned long) id; + u32 v0 = v; + u32 v1 = v >> 32; + u32 sum = 0; + int i; + + for (i = 0; i < 32; i++) { + v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]); + sum += 0x9E3779B9; + v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]); + } + + return (u64) v0 + ((u64) v1 << 32); +} + +/* + * Check if page is under writeback + * + * This is currently done by walking the list of writepage requests + * for the inode, which can be pretty inefficient. + */ +static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_req *req; + bool found = false; + + spin_lock(&fc->lock); + list_for_each_entry(req, &fi->writepages, writepages_entry) { + pgoff_t curr_index; + + BUG_ON(req->inode != inode); + curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT; + if (curr_index == index) { + found = true; + break; + } + } + spin_unlock(&fc->lock); + + return found; +} + +/* + * Wait for page writeback to be completed. + * + * Since fuse doesn't rely on the VM writeback tracking, this has to + * use some other means. + */ +static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index) +{ + struct fuse_inode *fi = get_fuse_inode(inode); + + wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index)); + return 0; +} + +static int fuse_flush(struct file *file, fl_owner_t id) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_file *ff = file->private_data; + struct fuse_req *req; + struct fuse_flush_in inarg; + int err; + + if (is_bad_inode(inode)) + return -EIO; + + if (fc->no_flush) + return 0; + + req = fuse_get_req_nofail(fc, file); + memset(&inarg, 0, sizeof(inarg)); + inarg.fh = ff->fh; + inarg.lock_owner = fuse_lock_owner_id(fc, id); + req->in.h.opcode = FUSE_FLUSH; + req->in.h.nodeid = get_node_id(inode); + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + req->force = 1; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (err == -ENOSYS) { + fc->no_flush = 1; + err = 0; + } + return err; +} + +/* + * Wait for all pending writepages on the inode to finish. + * + * This is currently done by blocking further writes with FUSE_NOWRITE + * and waiting for all sent writes to complete. + * + * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage + * could conflict with truncation. + */ +static void fuse_sync_writes(struct inode *inode) +{ + fuse_set_nowrite(inode); + fuse_release_nowrite(inode); +} + +int fuse_fsync_common(struct file *file, loff_t start, loff_t end, + int datasync, int isdir) +{ + struct inode *inode = file->f_mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_file *ff = file->private_data; + struct fuse_req *req; + struct fuse_fsync_in inarg; + int err; + + if (is_bad_inode(inode)) + return -EIO; + + err = filemap_write_and_wait_range(inode->i_mapping, start, end); + if (err) + return err; + + if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir)) + return 0; + + mutex_lock(&inode->i_mutex); + + /* + * Start writeback against all dirty pages of the inode, then + * wait for all outstanding writes, before sending the FSYNC + * request. + */ + err = write_inode_now(inode, 0); + if (err) + goto out; + + fuse_sync_writes(inode); + + req = fuse_get_req(fc); + if (IS_ERR(req)) { + err = PTR_ERR(req); + goto out; + } + + memset(&inarg, 0, sizeof(inarg)); + inarg.fh = ff->fh; + inarg.fsync_flags = datasync ? 1 : 0; + req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC; + req->in.h.nodeid = get_node_id(inode); + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (err == -ENOSYS) { + if (isdir) + fc->no_fsyncdir = 1; + else + fc->no_fsync = 1; + err = 0; + } +out: + mutex_unlock(&inode->i_mutex); + return err; +} + +static int fuse_fsync(struct file *file, loff_t start, loff_t end, + int datasync) +{ + return fuse_fsync_common(file, start, end, datasync, 0); +} + +void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos, + size_t count, int opcode) +{ + struct fuse_read_in *inarg = &req->misc.read.in; + struct fuse_file *ff = file->private_data; + + inarg->fh = ff->fh; + inarg->offset = pos; + inarg->size = count; + inarg->flags = file->f_flags; + req->in.h.opcode = opcode; + req->in.h.nodeid = ff->nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(struct fuse_read_in); + req->in.args[0].value = inarg; + req->out.argvar = 1; + req->out.numargs = 1; + req->out.args[0].size = count; +} + +static size_t fuse_send_read(struct fuse_req *req, struct file *file, + loff_t pos, size_t count, fl_owner_t owner) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + + fuse_read_fill(req, file, pos, count, FUSE_READ); + if (owner != NULL) { + struct fuse_read_in *inarg = &req->misc.read.in; + + inarg->read_flags |= FUSE_READ_LOCKOWNER; + inarg->lock_owner = fuse_lock_owner_id(fc, owner); + } + fuse_request_send(fc, req); + return req->out.args[0].size; +} + +static void fuse_read_update_size(struct inode *inode, loff_t size, + u64 attr_ver) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + + spin_lock(&fc->lock); + if (attr_ver == fi->attr_version && size < inode->i_size) { + fi->attr_version = ++fc->attr_version; + i_size_write(inode, size); + } + spin_unlock(&fc->lock); +} + +static int fuse_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + size_t num_read; + loff_t pos = page_offset(page); + size_t count = PAGE_CACHE_SIZE; + u64 attr_ver; + int err; + + err = -EIO; + if (is_bad_inode(inode)) + goto out; + + /* + * Page writeback can extend beyond the lifetime of the + * page-cache page, so make sure we read a properly synced + * page. + */ + fuse_wait_on_page_writeback(inode, page->index); + + req = fuse_get_req(fc); + err = PTR_ERR(req); + if (IS_ERR(req)) + goto out; + + attr_ver = fuse_get_attr_version(fc); + + req->out.page_zeroing = 1; + req->out.argpages = 1; + req->num_pages = 1; + req->pages[0] = page; + num_read = fuse_send_read(req, file, pos, count, NULL); + err = req->out.h.error; + fuse_put_request(fc, req); + + if (!err) { + /* + * Short read means EOF. If file size is larger, truncate it + */ + if (num_read < count) + fuse_read_update_size(inode, pos + num_read, attr_ver); + + SetPageUptodate(page); + } + + fuse_invalidate_attr(inode); /* atime changed */ + out: + unlock_page(page); + return err; +} + +static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req) +{ + int i; + size_t count = req->misc.read.in.size; + size_t num_read = req->out.args[0].size; + struct address_space *mapping = NULL; + + for (i = 0; mapping == NULL && i < req->num_pages; i++) + mapping = req->pages[i]->mapping; + + if (mapping) { + struct inode *inode = mapping->host; + + /* + * Short read means EOF. If file size is larger, truncate it + */ + if (!req->out.h.error && num_read < count) { + loff_t pos; + + pos = page_offset(req->pages[0]) + num_read; + fuse_read_update_size(inode, pos, + req->misc.read.attr_ver); + } + fuse_invalidate_attr(inode); /* atime changed */ + } + + for (i = 0; i < req->num_pages; i++) { + struct page *page = req->pages[i]; + if (!req->out.h.error) + SetPageUptodate(page); + else + SetPageError(page); + unlock_page(page); + page_cache_release(page); + } + if (req->ff) + fuse_file_put(req->ff, false); +} + +static void fuse_send_readpages(struct fuse_req *req, struct file *file) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + loff_t pos = page_offset(req->pages[0]); + size_t count = req->num_pages << PAGE_CACHE_SHIFT; + + req->out.argpages = 1; + req->out.page_zeroing = 1; + req->out.page_replace = 1; + fuse_read_fill(req, file, pos, count, FUSE_READ); + req->misc.read.attr_ver = fuse_get_attr_version(fc); + if (fc->async_read) { + req->ff = fuse_file_get(ff); + req->end = fuse_readpages_end; + fuse_request_send_background(fc, req); + } else { + fuse_request_send(fc, req); + fuse_readpages_end(fc, req); + fuse_put_request(fc, req); + } +} + +struct fuse_fill_data { + struct fuse_req *req; + struct file *file; + struct inode *inode; +}; + +static int fuse_readpages_fill(void *_data, struct page *page) +{ + struct fuse_fill_data *data = _data; + struct fuse_req *req = data->req; + struct inode *inode = data->inode; + struct fuse_conn *fc = get_fuse_conn(inode); + + fuse_wait_on_page_writeback(inode, page->index); + + if (req->num_pages && + (req->num_pages == FUSE_MAX_PAGES_PER_REQ || + (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read || + req->pages[req->num_pages - 1]->index + 1 != page->index)) { + fuse_send_readpages(req, data->file); + data->req = req = fuse_get_req(fc); + if (IS_ERR(req)) { + unlock_page(page); + return PTR_ERR(req); + } + } + page_cache_get(page); + req->pages[req->num_pages] = page; + req->num_pages++; + return 0; +} + +static int fuse_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) +{ + struct inode *inode = mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_fill_data data; + int err; + + err = -EIO; + if (is_bad_inode(inode)) + goto out; + + data.file = file; + data.inode = inode; + data.req = fuse_get_req(fc); + err = PTR_ERR(data.req); + if (IS_ERR(data.req)) + goto out; + + err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); + if (!err) { + if (data.req->num_pages) + fuse_send_readpages(data.req, file); + else + fuse_put_request(fc, data.req); + } +out: + return err; +} + +static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct inode *inode = iocb->ki_filp->f_mapping->host; + + if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) { + int err; + /* + * If trying to read past EOF, make sure the i_size + * attribute is up-to-date. + */ + err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL); + if (err) + return err; + } + + return generic_file_aio_read(iocb, iov, nr_segs, pos); +} + +static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff, + loff_t pos, size_t count) +{ + struct fuse_write_in *inarg = &req->misc.write.in; + struct fuse_write_out *outarg = &req->misc.write.out; + + inarg->fh = ff->fh; + inarg->offset = pos; + inarg->size = count; + req->in.h.opcode = FUSE_WRITE; + req->in.h.nodeid = ff->nodeid; + req->in.numargs = 2; + if (ff->fc->minor < 9) + req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE; + else + req->in.args[0].size = sizeof(struct fuse_write_in); + req->in.args[0].value = inarg; + req->in.args[1].size = count; + req->out.numargs = 1; + req->out.args[0].size = sizeof(struct fuse_write_out); + req->out.args[0].value = outarg; +} + +static size_t fuse_send_write(struct fuse_req *req, struct file *file, + loff_t pos, size_t count, fl_owner_t owner) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + struct fuse_write_in *inarg = &req->misc.write.in; + + fuse_write_fill(req, ff, pos, count); + inarg->flags = file->f_flags; + if (owner != NULL) { + inarg->write_flags |= FUSE_WRITE_LOCKOWNER; + inarg->lock_owner = fuse_lock_owner_id(fc, owner); + } + fuse_request_send(fc, req); + return req->misc.write.out.size; +} + +void fuse_write_update_size(struct inode *inode, loff_t pos) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + + spin_lock(&fc->lock); + fi->attr_version = ++fc->attr_version; + if (pos > inode->i_size) + i_size_write(inode, pos); + spin_unlock(&fc->lock); +} + +static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file, + struct inode *inode, loff_t pos, + size_t count) +{ + size_t res; + unsigned offset; + unsigned i; + + for (i = 0; i < req->num_pages; i++) + fuse_wait_on_page_writeback(inode, req->pages[i]->index); + + res = fuse_send_write(req, file, pos, count, NULL); + + offset = req->page_offset; + count = res; + for (i = 0; i < req->num_pages; i++) { + struct page *page = req->pages[i]; + + if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE) + SetPageUptodate(page); + + if (count > PAGE_CACHE_SIZE - offset) + count -= PAGE_CACHE_SIZE - offset; + else + count = 0; + offset = 0; + + unlock_page(page); + page_cache_release(page); + } + + return res; +} + +static ssize_t fuse_fill_write_pages(struct fuse_req *req, + struct address_space *mapping, + struct iov_iter *ii, loff_t pos) +{ + struct fuse_conn *fc = get_fuse_conn(mapping->host); + unsigned offset = pos & (PAGE_CACHE_SIZE - 1); + size_t count = 0; + int err; + + req->in.argpages = 1; + req->page_offset = offset; + + do { + size_t tmp; + struct page *page; + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset, + iov_iter_count(ii)); + + bytes = min_t(size_t, bytes, fc->max_write - count); + + again: + err = -EFAULT; + if (iov_iter_fault_in_readable(ii, bytes)) + break; + + err = -ENOMEM; + page = grab_cache_page_write_begin(mapping, index, 0); + if (!page) + break; + + if (mapping_writably_mapped(mapping)) + flush_dcache_page(page); + + pagefault_disable(); + tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); + pagefault_enable(); + flush_dcache_page(page); + + mark_page_accessed(page); + + if (!tmp) { + unlock_page(page); + page_cache_release(page); + bytes = min(bytes, iov_iter_single_seg_count(ii)); + goto again; + } + + err = 0; + req->pages[req->num_pages] = page; + req->num_pages++; + + iov_iter_advance(ii, tmp); + count += tmp; + pos += tmp; + offset += tmp; + if (offset == PAGE_CACHE_SIZE) + offset = 0; + + if (!fc->big_writes) + break; + } while (iov_iter_count(ii) && count < fc->max_write && + req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0); + + return count > 0 ? count : err; +} + +static ssize_t fuse_perform_write(struct file *file, + struct address_space *mapping, + struct iov_iter *ii, loff_t pos) +{ + struct inode *inode = mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + int err = 0; + ssize_t res = 0; + + if (is_bad_inode(inode)) + return -EIO; + + do { + struct fuse_req *req; + ssize_t count; + + req = fuse_get_req(fc); + if (IS_ERR(req)) { + err = PTR_ERR(req); + break; + } + + count = fuse_fill_write_pages(req, mapping, ii, pos); + if (count <= 0) { + err = count; + } else { + size_t num_written; + + num_written = fuse_send_write_pages(req, file, inode, + pos, count); + err = req->out.h.error; + if (!err) { + res += num_written; + pos += num_written; + + /* break out of the loop on short write */ + if (num_written != count) + err = -EIO; + } + } + fuse_put_request(fc, req); + } while (!err && iov_iter_count(ii)); + + if (res > 0) + fuse_write_update_size(inode, pos); + + fuse_invalidate_attr(inode); + + return res > 0 ? res : err; +} + +static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct file *file = iocb->ki_filp; + struct address_space *mapping = file->f_mapping; + size_t count = 0; + size_t ocount = 0; + ssize_t written = 0; + ssize_t written_buffered = 0; + struct inode *inode = mapping->host; + ssize_t err; + struct iov_iter i; + loff_t endbyte = 0; + + WARN_ON(iocb->ki_pos != pos); + + ocount = 0; + err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); + if (err) + return err; + + count = ocount; + + mutex_lock(&inode->i_mutex); + vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + + /* We can write back this queue in page reclaim */ + current->backing_dev_info = mapping->backing_dev_info; + + err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); + if (err) + goto out; + + if (count == 0) + goto out; + + err = file_remove_suid(file); + if (err) + goto out; + + file_update_time(file); + + if (file->f_flags & O_DIRECT) { + written = generic_file_direct_write(iocb, iov, &nr_segs, + pos, &iocb->ki_pos, + count, ocount); + if (written < 0 || written == count) + goto out; + + pos += written; + count -= written; + + iov_iter_init(&i, iov, nr_segs, count, written); + written_buffered = fuse_perform_write(file, mapping, &i, pos); + if (written_buffered < 0) { + err = written_buffered; + goto out; + } + endbyte = pos + written_buffered - 1; + + err = filemap_write_and_wait_range(file->f_mapping, pos, + endbyte); + if (err) + goto out; + + invalidate_mapping_pages(file->f_mapping, + pos >> PAGE_CACHE_SHIFT, + endbyte >> PAGE_CACHE_SHIFT); + + written += written_buffered; + iocb->ki_pos = pos + written_buffered; + } else { + iov_iter_init(&i, iov, nr_segs, count, 0); + written = fuse_perform_write(file, mapping, &i, pos); + if (written >= 0) + iocb->ki_pos = pos + written; + } +out: + current->backing_dev_info = NULL; + mutex_unlock(&inode->i_mutex); + + return written ? written : err; +} + +static void fuse_release_user_pages(struct fuse_req *req, int write) +{ + unsigned i; + + for (i = 0; i < req->num_pages; i++) { + struct page *page = req->pages[i]; + if (write) + set_page_dirty_lock(page); + put_page(page); + } +} + +static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf, + size_t *nbytesp, int write) +{ + size_t nbytes = *nbytesp; + unsigned long user_addr = (unsigned long) buf; + unsigned offset = user_addr & ~PAGE_MASK; + int npages; + + /* Special case for kernel I/O: can copy directly into the buffer */ + if (segment_eq(get_fs(), KERNEL_DS)) { + if (write) + req->in.args[1].value = (void *) user_addr; + else + req->out.args[0].value = (void *) user_addr; + + return 0; + } + + nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); + npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; + npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ); + npages = get_user_pages_fast(user_addr, npages, !write, req->pages); + if (npages < 0) + return npages; + + req->num_pages = npages; + req->page_offset = offset; + + if (write) + req->in.argpages = 1; + else + req->out.argpages = 1; + + nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; + *nbytesp = min(*nbytesp, nbytes); + + return 0; +} + +ssize_t fuse_direct_io(struct file *file, const char __user *buf, + size_t count, loff_t *ppos, int write) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + size_t nmax = write ? fc->max_write : fc->max_read; + loff_t pos = *ppos; + ssize_t res = 0; + struct fuse_req *req; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + while (count) { + size_t nres; + fl_owner_t owner = current->files; + size_t nbytes = min(count, nmax); + int err = fuse_get_user_pages(req, buf, &nbytes, write); + if (err) { + res = err; + break; + } + + if (write) + nres = fuse_send_write(req, file, pos, nbytes, owner); + else + nres = fuse_send_read(req, file, pos, nbytes, owner); + + fuse_release_user_pages(req, !write); + if (req->out.h.error) { + if (!res) + res = req->out.h.error; + break; + } else if (nres > nbytes) { + res = -EIO; + break; + } + count -= nres; + res += nres; + pos += nres; + buf += nres; + if (nres != nbytes) + break; + if (count) { + fuse_put_request(fc, req); + req = fuse_get_req(fc); + if (IS_ERR(req)) + break; + } + } + if (!IS_ERR(req)) + fuse_put_request(fc, req); + if (res > 0) + *ppos = pos; + + return res; +} +EXPORT_SYMBOL_GPL(fuse_direct_io); + +static ssize_t fuse_direct_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + ssize_t res; + struct inode *inode = file->f_path.dentry->d_inode; + + if (is_bad_inode(inode)) + return -EIO; + + res = fuse_direct_io(file, buf, count, ppos, 0); + + fuse_invalidate_attr(inode); + + return res; +} + +static ssize_t __fuse_direct_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file->f_path.dentry->d_inode; + ssize_t res; + + res = generic_write_checks(file, ppos, &count, 0); + if (!res) { + res = fuse_direct_io(file, buf, count, ppos, 1); + if (res > 0) + fuse_write_update_size(inode, *ppos); + } + + fuse_invalidate_attr(inode); + + return res; +} + +static ssize_t fuse_direct_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file->f_path.dentry->d_inode; + ssize_t res; + + if (is_bad_inode(inode)) + return -EIO; + + /* Don't allow parallel writes to the same file */ + mutex_lock(&inode->i_mutex); + res = __fuse_direct_write(file, buf, count, ppos); + mutex_unlock(&inode->i_mutex); + + return res; +} + +static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req) +{ + __free_page(req->pages[0]); + fuse_file_put(req->ff, false); +} + +static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req) +{ + struct inode *inode = req->inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info; + + list_del(&req->writepages_entry); + dec_bdi_stat(bdi, BDI_WRITEBACK); + dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP); + bdi_writeout_inc(bdi); + wake_up(&fi->page_waitq); +} + +/* Called under fc->lock, may release and reacquire it */ +static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req) +__releases(fc->lock) +__acquires(fc->lock) +{ + struct fuse_inode *fi = get_fuse_inode(req->inode); + loff_t size = i_size_read(req->inode); + struct fuse_write_in *inarg = &req->misc.write.in; + + if (!fc->connected) + goto out_free; + + if (inarg->offset + PAGE_CACHE_SIZE <= size) { + inarg->size = PAGE_CACHE_SIZE; + } else if (inarg->offset < size) { + inarg->size = size & (PAGE_CACHE_SIZE - 1); + } else { + /* Got truncated off completely */ + goto out_free; + } + + req->in.args[1].size = inarg->size; + fi->writectr++; + fuse_request_send_background_locked(fc, req); + return; + + out_free: + fuse_writepage_finish(fc, req); + spin_unlock(&fc->lock); + fuse_writepage_free(fc, req); + fuse_put_request(fc, req); + spin_lock(&fc->lock); +} + +/* + * If fi->writectr is positive (no truncate or fsync going on) send + * all queued writepage requests. + * + * Called with fc->lock + */ +void fuse_flush_writepages(struct inode *inode) +__releases(fc->lock) +__acquires(fc->lock) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_req *req; + + while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) { + req = list_entry(fi->queued_writes.next, struct fuse_req, list); + list_del_init(&req->list); + fuse_send_writepage(fc, req); + } +} + +static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req) +{ + struct inode *inode = req->inode; + struct fuse_inode *fi = get_fuse_inode(inode); + + mapping_set_error(inode->i_mapping, req->out.h.error); + spin_lock(&fc->lock); + fi->writectr--; + fuse_writepage_finish(fc, req); + spin_unlock(&fc->lock); + fuse_writepage_free(fc, req); +} + +static int fuse_writepage_locked(struct page *page) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_req *req; + struct fuse_file *ff; + struct page *tmp_page; + + set_page_writeback(page); + + req = fuse_request_alloc_nofs(); + if (!req) + goto err; + + tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (!tmp_page) + goto err_free; + + spin_lock(&fc->lock); + BUG_ON(list_empty(&fi->write_files)); + ff = list_entry(fi->write_files.next, struct fuse_file, write_entry); + req->ff = fuse_file_get(ff); + spin_unlock(&fc->lock); + + fuse_write_fill(req, ff, page_offset(page), 0); + + copy_highpage(tmp_page, page); + req->misc.write.in.write_flags |= FUSE_WRITE_CACHE; + req->in.argpages = 1; + req->num_pages = 1; + req->pages[0] = tmp_page; + req->page_offset = 0; + req->end = fuse_writepage_end; + req->inode = inode; + + inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK); + inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP); + end_page_writeback(page); + + spin_lock(&fc->lock); + list_add(&req->writepages_entry, &fi->writepages); + list_add_tail(&req->list, &fi->queued_writes); + fuse_flush_writepages(inode); + spin_unlock(&fc->lock); + + return 0; + +err_free: + fuse_request_free(req); +err: + end_page_writeback(page); + return -ENOMEM; +} + +static int fuse_writepage(struct page *page, struct writeback_control *wbc) +{ + int err; + + err = fuse_writepage_locked(page); + unlock_page(page); + + return err; +} + +static int fuse_launder_page(struct page *page) +{ + int err = 0; + if (clear_page_dirty_for_io(page)) { + struct inode *inode = page->mapping->host; + err = fuse_writepage_locked(page); + if (!err) + fuse_wait_on_page_writeback(inode, page->index); + } + return err; +} + +/* + * Write back dirty pages now, because there may not be any suitable + * open files later + */ +static void fuse_vma_close(struct vm_area_struct *vma) +{ + filemap_write_and_wait(vma->vm_file->f_mapping); +} + +/* + * Wait for writeback against this page to complete before allowing it + * to be marked dirty again, and hence written back again, possibly + * before the previous writepage completed. + * + * Block here, instead of in ->writepage(), so that the userspace fs + * can only block processes actually operating on the filesystem. + * + * Otherwise unprivileged userspace fs would be able to block + * unrelated: + * + * - page migration + * - sync(2) + * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER + */ +static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + /* + * Don't use page->mapping as it may become NULL from a + * concurrent truncate. + */ + struct inode *inode = vma->vm_file->f_mapping->host; + + fuse_wait_on_page_writeback(inode, page->index); + return 0; +} + +static const struct vm_operations_struct fuse_file_vm_ops = { + .close = fuse_vma_close, + .fault = filemap_fault, + .page_mkwrite = fuse_page_mkwrite, +}; + +static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) +{ + if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) { + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_file *ff = file->private_data; + /* + * file may be written through mmap, so chain it onto the + * inodes's write_file list + */ + spin_lock(&fc->lock); + if (list_empty(&ff->write_entry)) + list_add(&ff->write_entry, &fi->write_files); + spin_unlock(&fc->lock); + } + file_accessed(file); + vma->vm_ops = &fuse_file_vm_ops; + return 0; +} + +static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma) +{ + /* Can't provide the coherency needed for MAP_SHARED */ + if (vma->vm_flags & VM_MAYSHARE) + return -ENODEV; + + invalidate_inode_pages2(file->f_mapping); + + return generic_file_mmap(file, vma); +} + +static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, + struct file_lock *fl) +{ + switch (ffl->type) { + case F_UNLCK: + break; + + case F_RDLCK: + case F_WRLCK: + if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX || + ffl->end < ffl->start) + return -EIO; + + fl->fl_start = ffl->start; + fl->fl_end = ffl->end; + fl->fl_pid = ffl->pid; + break; + + default: + return -EIO; + } + fl->fl_type = ffl->type; + return 0; +} + +static void fuse_lk_fill(struct fuse_req *req, struct file *file, + const struct file_lock *fl, int opcode, pid_t pid, + int flock) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_file *ff = file->private_data; + struct fuse_lk_in *arg = &req->misc.lk_in; + + arg->fh = ff->fh; + arg->owner = fuse_lock_owner_id(fc, fl->fl_owner); + arg->lk.start = fl->fl_start; + arg->lk.end = fl->fl_end; + arg->lk.type = fl->fl_type; + arg->lk.pid = pid; + if (flock) + arg->lk_flags |= FUSE_LK_FLOCK; + req->in.h.opcode = opcode; + req->in.h.nodeid = get_node_id(inode); + req->in.numargs = 1; + req->in.args[0].size = sizeof(*arg); + req->in.args[0].value = arg; +} + +static int fuse_getlk(struct file *file, struct file_lock *fl) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + struct fuse_lk_out outarg; + int err; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0); + req->out.numargs = 1; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) + err = convert_fuse_file_lock(&outarg.lk, fl); + + return err; +} + +static int fuse_setlk(struct file *file, struct file_lock *fl, int flock) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; + pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0; + int err; + + if (fl->fl_lmops && fl->fl_lmops->lm_grant) { + /* NLM needs asynchronous locks, which we don't support yet */ + return -ENOLCK; + } + + /* Unlock on close is handled by the flush method */ + if (fl->fl_flags & FL_CLOSE) + return 0; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + fuse_lk_fill(req, file, fl, opcode, pid, flock); + fuse_request_send(fc, req); + err = req->out.h.error; + /* locking is restartable */ + if (err == -EINTR) + err = -ERESTARTSYS; + fuse_put_request(fc, req); + return err; +} + +static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + if (cmd == F_CANCELLK) { + err = 0; + } else if (cmd == F_GETLK) { + if (fc->no_lock) { + posix_test_lock(file, fl); + err = 0; + } else + err = fuse_getlk(file, fl); + } else { + if (fc->no_lock) + err = posix_lock_file(file, fl, NULL); + else + err = fuse_setlk(file, fl, 0); + } + return err; +} + +static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + if (fc->no_flock) { + err = flock_lock_file_wait(file, fl); + } else { + struct fuse_file *ff = file->private_data; + + /* emulate flock with POSIX locks */ + fl->fl_owner = (fl_owner_t) file; + ff->flock = true; + err = fuse_setlk(file, fl, 1); + } + + return err; +} + +static sector_t fuse_bmap(struct address_space *mapping, sector_t block) +{ + struct inode *inode = mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + struct fuse_bmap_in inarg; + struct fuse_bmap_out outarg; + int err; + + if (!inode->i_sb->s_bdev || fc->no_bmap) + return 0; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return 0; + + memset(&inarg, 0, sizeof(inarg)); + inarg.block = block; + inarg.blocksize = inode->i_sb->s_blocksize; + req->in.h.opcode = FUSE_BMAP; + req->in.h.nodeid = get_node_id(inode); + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + req->out.numargs = 1; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (err == -ENOSYS) + fc->no_bmap = 1; + + return err ? 0 : outarg.block; +} + +static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin) +{ + loff_t retval; + struct inode *inode = file->f_path.dentry->d_inode; + + /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */ + if (origin == SEEK_CUR || origin == SEEK_SET) + return generic_file_llseek(file, offset, origin); + + mutex_lock(&inode->i_mutex); + retval = fuse_update_attributes(inode, NULL, file, NULL); + if (!retval) + retval = generic_file_llseek(file, offset, origin); + mutex_unlock(&inode->i_mutex); + + return retval; +} + +static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov, + unsigned int nr_segs, size_t bytes, bool to_user) +{ + struct iov_iter ii; + int page_idx = 0; + + if (!bytes) + return 0; + + iov_iter_init(&ii, iov, nr_segs, bytes, 0); + + while (iov_iter_count(&ii)) { + struct page *page = pages[page_idx++]; + size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii)); + void *kaddr; + + kaddr = kmap(page); + + while (todo) { + char __user *uaddr = ii.iov->iov_base + ii.iov_offset; + size_t iov_len = ii.iov->iov_len - ii.iov_offset; + size_t copy = min(todo, iov_len); + size_t left; + + if (!to_user) + left = copy_from_user(kaddr, uaddr, copy); + else + left = copy_to_user(uaddr, kaddr, copy); + + if (unlikely(left)) + return -EFAULT; + + iov_iter_advance(&ii, copy); + todo -= copy; + kaddr += copy; + } + + kunmap(page); + } + + return 0; +} + +/* + * CUSE servers compiled on 32bit broke on 64bit kernels because the + * ABI was defined to be 'struct iovec' which is different on 32bit + * and 64bit. Fortunately we can determine which structure the server + * used from the size of the reply. + */ +static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src, + size_t transferred, unsigned count, + bool is_compat) +{ +#ifdef CONFIG_COMPAT + if (count * sizeof(struct compat_iovec) == transferred) { + struct compat_iovec *ciov = src; + unsigned i; + + /* + * With this interface a 32bit server cannot support + * non-compat (i.e. ones coming from 64bit apps) ioctl + * requests + */ + if (!is_compat) + return -EINVAL; + + for (i = 0; i < count; i++) { + dst[i].iov_base = compat_ptr(ciov[i].iov_base); + dst[i].iov_len = ciov[i].iov_len; + } + return 0; + } +#endif + + if (count * sizeof(struct iovec) != transferred) + return -EIO; + + memcpy(dst, src, transferred); + return 0; +} + +/* Make sure iov_length() won't overflow */ +static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count) +{ + size_t n; + u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT; + + for (n = 0; n < count; n++) { + if (iov->iov_len > (size_t) max) + return -ENOMEM; + max -= iov->iov_len; + } + return 0; +} + +static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst, + void *src, size_t transferred, unsigned count, + bool is_compat) +{ + unsigned i; + struct fuse_ioctl_iovec *fiov = src; + + if (fc->minor < 16) { + return fuse_copy_ioctl_iovec_old(dst, src, transferred, + count, is_compat); + } + + if (count * sizeof(struct fuse_ioctl_iovec) != transferred) + return -EIO; + + for (i = 0; i < count; i++) { + /* Did the server supply an inappropriate value? */ + if (fiov[i].base != (unsigned long) fiov[i].base || + fiov[i].len != (unsigned long) fiov[i].len) + return -EIO; + + dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base; + dst[i].iov_len = (size_t) fiov[i].len; + +#ifdef CONFIG_COMPAT + if (is_compat && + (ptr_to_compat(dst[i].iov_base) != fiov[i].base || + (compat_size_t) dst[i].iov_len != fiov[i].len)) + return -EIO; +#endif + } + + return 0; +} + + +/* + * For ioctls, there is no generic way to determine how much memory + * needs to be read and/or written. Furthermore, ioctls are allowed + * to dereference the passed pointer, so the parameter requires deep + * copying but FUSE has no idea whatsoever about what to copy in or + * out. + * + * This is solved by allowing FUSE server to retry ioctl with + * necessary in/out iovecs. Let's assume the ioctl implementation + * needs to read in the following structure. + * + * struct a { + * char *buf; + * size_t buflen; + * } + * + * On the first callout to FUSE server, inarg->in_size and + * inarg->out_size will be NULL; then, the server completes the ioctl + * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and + * the actual iov array to + * + * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } + * + * which tells FUSE to copy in the requested area and retry the ioctl. + * On the second round, the server has access to the structure and + * from that it can tell what to look for next, so on the invocation, + * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to + * + * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, + * { .iov_base = a.buf, .iov_len = a.buflen } } + * + * FUSE will copy both struct a and the pointed buffer from the + * process doing the ioctl and retry ioctl with both struct a and the + * buffer. + * + * This time, FUSE server has everything it needs and completes ioctl + * without FUSE_IOCTL_RETRY which finishes the ioctl call. + * + * Copying data out works the same way. + * + * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel + * automatically initializes in and out iovs by decoding @cmd with + * _IOC_* macros and the server is not allowed to request RETRY. This + * limits ioctl data transfers to well-formed ioctls and is the forced + * behavior for all FUSE servers. + */ +long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, + unsigned int flags) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + struct fuse_ioctl_in inarg = { + .fh = ff->fh, + .cmd = cmd, + .arg = arg, + .flags = flags + }; + struct fuse_ioctl_out outarg; + struct fuse_req *req = NULL; + struct page **pages = NULL; + struct iovec *iov_page = NULL; + struct iovec *in_iov = NULL, *out_iov = NULL; + unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages; + size_t in_size, out_size, transferred; + int err; + +#if BITS_PER_LONG == 32 + inarg.flags |= FUSE_IOCTL_32BIT; +#else + if (flags & FUSE_IOCTL_COMPAT) + inarg.flags |= FUSE_IOCTL_32BIT; +#endif + + /* assume all the iovs returned by client always fits in a page */ + BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); + + err = -ENOMEM; + pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL); + iov_page = (struct iovec *) __get_free_page(GFP_KERNEL); + if (!pages || !iov_page) + goto out; + + /* + * If restricted, initialize IO parameters as encoded in @cmd. + * RETRY from server is not allowed. + */ + if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { + struct iovec *iov = iov_page; + + iov->iov_base = (void __user *)arg; + iov->iov_len = _IOC_SIZE(cmd); + + if (_IOC_DIR(cmd) & _IOC_WRITE) { + in_iov = iov; + in_iovs = 1; + } + + if (_IOC_DIR(cmd) & _IOC_READ) { + out_iov = iov; + out_iovs = 1; + } + } + + retry: + inarg.in_size = in_size = iov_length(in_iov, in_iovs); + inarg.out_size = out_size = iov_length(out_iov, out_iovs); + + /* + * Out data can be used either for actual out data or iovs, + * make sure there always is at least one page. + */ + out_size = max_t(size_t, out_size, PAGE_SIZE); + max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); + + /* make sure there are enough buffer pages and init request with them */ + err = -ENOMEM; + if (max_pages > FUSE_MAX_PAGES_PER_REQ) + goto out; + while (num_pages < max_pages) { + pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); + if (!pages[num_pages]) + goto out; + num_pages++; + } + + req = fuse_get_req(fc); + if (IS_ERR(req)) { + err = PTR_ERR(req); + req = NULL; + goto out; + } + memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages); + req->num_pages = num_pages; + + /* okay, let's send it to the client */ + req->in.h.opcode = FUSE_IOCTL; + req->in.h.nodeid = ff->nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + if (in_size) { + req->in.numargs++; + req->in.args[1].size = in_size; + req->in.argpages = 1; + + err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size, + false); + if (err) + goto out; + } + + req->out.numargs = 2; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + req->out.args[1].size = out_size; + req->out.argpages = 1; + req->out.argvar = 1; + + fuse_request_send(fc, req); + err = req->out.h.error; + transferred = req->out.args[1].size; + fuse_put_request(fc, req); + req = NULL; + if (err) + goto out; + + /* did it ask for retry? */ + if (outarg.flags & FUSE_IOCTL_RETRY) { + void *vaddr; + + /* no retry if in restricted mode */ + err = -EIO; + if (!(flags & FUSE_IOCTL_UNRESTRICTED)) + goto out; + + in_iovs = outarg.in_iovs; + out_iovs = outarg.out_iovs; + + /* + * Make sure things are in boundary, separate checks + * are to protect against overflow. + */ + err = -ENOMEM; + if (in_iovs > FUSE_IOCTL_MAX_IOV || + out_iovs > FUSE_IOCTL_MAX_IOV || + in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) + goto out; + + vaddr = kmap_atomic(pages[0]); + err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr, + transferred, in_iovs + out_iovs, + (flags & FUSE_IOCTL_COMPAT) != 0); + kunmap_atomic(vaddr); + if (err) + goto out; + + in_iov = iov_page; + out_iov = in_iov + in_iovs; + + err = fuse_verify_ioctl_iov(in_iov, in_iovs); + if (err) + goto out; + + err = fuse_verify_ioctl_iov(out_iov, out_iovs); + if (err) + goto out; + + goto retry; + } + + err = -EIO; + if (transferred > inarg.out_size) + goto out; + + err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true); + out: + if (req) + fuse_put_request(fc, req); + free_page((unsigned long) iov_page); + while (num_pages) + __free_page(pages[--num_pages]); + kfree(pages); + + return err ? err : outarg.result; +} +EXPORT_SYMBOL_GPL(fuse_do_ioctl); + +long fuse_ioctl_common(struct file *file, unsigned int cmd, + unsigned long arg, unsigned int flags) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + + if (!fuse_allow_task(fc, current)) + return -EACCES; + + if (is_bad_inode(inode)) + return -EIO; + + return fuse_do_ioctl(file, cmd, arg, flags); +} + +static long fuse_file_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return fuse_ioctl_common(file, cmd, arg, 0); +} + +static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); +} + +/* + * All files which have been polled are linked to RB tree + * fuse_conn->polled_files which is indexed by kh. Walk the tree and + * find the matching one. + */ +static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh, + struct rb_node **parent_out) +{ + struct rb_node **link = &fc->polled_files.rb_node; + struct rb_node *last = NULL; + + while (*link) { + struct fuse_file *ff; + + last = *link; + ff = rb_entry(last, struct fuse_file, polled_node); + + if (kh < ff->kh) + link = &last->rb_left; + else if (kh > ff->kh) + link = &last->rb_right; + else + return link; + } + + if (parent_out) + *parent_out = last; + return link; +} + +/* + * The file is about to be polled. Make sure it's on the polled_files + * RB tree. Note that files once added to the polled_files tree are + * not removed before the file is released. This is because a file + * polled once is likely to be polled again. + */ +static void fuse_register_polled_file(struct fuse_conn *fc, + struct fuse_file *ff) +{ + spin_lock(&fc->lock); + if (RB_EMPTY_NODE(&ff->polled_node)) { + struct rb_node **link, *parent; + + link = fuse_find_polled_node(fc, ff->kh, &parent); + BUG_ON(*link); + rb_link_node(&ff->polled_node, parent, link); + rb_insert_color(&ff->polled_node, &fc->polled_files); + } + spin_unlock(&fc->lock); +} + +unsigned fuse_file_poll(struct file *file, poll_table *wait) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = ff->fc; + struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh }; + struct fuse_poll_out outarg; + struct fuse_req *req; + int err; + + if (fc->no_poll) + return DEFAULT_POLLMASK; + + poll_wait(file, &ff->poll_wait, wait); + + /* + * Ask for notification iff there's someone waiting for it. + * The client may ignore the flag and always notify. + */ + if (waitqueue_active(&ff->poll_wait)) { + inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY; + fuse_register_polled_file(fc, ff); + } + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return POLLERR; + + req->in.h.opcode = FUSE_POLL; + req->in.h.nodeid = ff->nodeid; + req->in.numargs = 1; + req->in.args[0].size = sizeof(inarg); + req->in.args[0].value = &inarg; + req->out.numargs = 1; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + fuse_request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + + if (!err) + return outarg.revents; + if (err == -ENOSYS) { + fc->no_poll = 1; + return DEFAULT_POLLMASK; + } + return POLLERR; +} +EXPORT_SYMBOL_GPL(fuse_file_poll); + +/* + * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and + * wakes up the poll waiters. + */ +int fuse_notify_poll_wakeup(struct fuse_conn *fc, + struct fuse_notify_poll_wakeup_out *outarg) +{ + u64 kh = outarg->kh; + struct rb_node **link; + + spin_lock(&fc->lock); + + link = fuse_find_polled_node(fc, kh, NULL); + if (*link) { + struct fuse_file *ff; + + ff = rb_entry(*link, struct fuse_file, polled_node); + wake_up_interruptible_sync(&ff->poll_wait); + } + + spin_unlock(&fc->lock); + return 0; +} + +static ssize_t fuse_loop_dio(struct file *filp, const struct iovec *iov, + unsigned long nr_segs, loff_t *ppos, int rw) +{ + const struct iovec *vector = iov; + ssize_t ret = 0; + + while (nr_segs > 0) { + void __user *base; + size_t len; + ssize_t nr; + + base = vector->iov_base; + len = vector->iov_len; + vector++; + nr_segs--; + + if (rw == WRITE) + nr = __fuse_direct_write(filp, base, len, ppos); + else + nr = fuse_direct_read(filp, base, len, ppos); + + if (nr < 0) { + if (!ret) + ret = nr; + break; + } + ret += nr; + if (nr != len) + break; + } + + return ret; +} + + +static ssize_t +fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + ssize_t ret = 0; + struct file *file = NULL; + loff_t pos = 0; + + file = iocb->ki_filp; + pos = offset; + + ret = fuse_loop_dio(file, iov, nr_segs, &pos, rw); + + return ret; +} + +static const struct file_operations fuse_file_operations = { + .llseek = fuse_file_llseek, + .read = do_sync_read, + .aio_read = fuse_file_aio_read, + .write = do_sync_write, + .aio_write = fuse_file_aio_write, + .mmap = fuse_file_mmap, + .open = fuse_open, + .flush = fuse_flush, + .release = fuse_release, + .fsync = fuse_fsync, + .lock = fuse_file_lock, + .flock = fuse_file_flock, + .splice_read = generic_file_splice_read, + .unlocked_ioctl = fuse_file_ioctl, + .compat_ioctl = fuse_file_compat_ioctl, + .poll = fuse_file_poll, +}; + +static const struct file_operations fuse_direct_io_file_operations = { + .llseek = fuse_file_llseek, + .read = fuse_direct_read, + .write = fuse_direct_write, + .mmap = fuse_direct_mmap, + .open = fuse_open, + .flush = fuse_flush, + .release = fuse_release, + .fsync = fuse_fsync, + .lock = fuse_file_lock, + .flock = fuse_file_flock, + .unlocked_ioctl = fuse_file_ioctl, + .compat_ioctl = fuse_file_compat_ioctl, + .poll = fuse_file_poll, + /* no splice_read */ +}; + +static const struct address_space_operations fuse_file_aops = { + .readpage = fuse_readpage, + .writepage = fuse_writepage, + .launder_page = fuse_launder_page, + .readpages = fuse_readpages, + .set_page_dirty = __set_page_dirty_nobuffers, + .bmap = fuse_bmap, + .direct_IO = fuse_direct_IO, +}; + +void fuse_init_file_inode(struct inode *inode) +{ + inode->i_fop = &fuse_file_operations; + inode->i_data.a_ops = &fuse_file_aops; +} |