/* FUSE: Filesystem in Userspace Copyright (C) 2001-2006 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> static const struct file_operations fuse_direct_io_file_operations; static int fuse_send_open(struct inode *inode, struct file *file, int isdir, struct fuse_open_out *outargp) { struct fuse_conn *fc = get_fuse_conn(inode); 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 = isdir ? FUSE_OPENDIR : FUSE_OPEN; 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(*outargp); req->out.args[0].value = outargp; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); return err; } struct fuse_file *fuse_file_alloc(void) { struct fuse_file *ff; ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); if (ff) { ff->reserved_req = fuse_request_alloc(); if (!ff->reserved_req) { kfree(ff); ff = NULL; } else { INIT_LIST_HEAD(&ff->write_entry); atomic_set(&ff->count, 0); } } return ff; } void fuse_file_free(struct fuse_file *ff) { fuse_request_free(ff->reserved_req); kfree(ff); } static struct fuse_file *fuse_file_get(struct fuse_file *ff) { atomic_inc(&ff->count); return ff; } static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req) { dput(req->misc.release.dentry); mntput(req->misc.release.vfsmount); fuse_put_request(fc, req); } static void fuse_file_put(struct fuse_file *ff) { if (atomic_dec_and_test(&ff->count)) { struct fuse_req *req = ff->reserved_req; struct inode *inode = req->misc.release.dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); req->end = fuse_release_end; request_send_background(fc, req); kfree(ff); } } void fuse_finish_open(struct inode *inode, struct file *file, struct fuse_file *ff, struct fuse_open_out *outarg) { if (outarg->open_flags & FOPEN_DIRECT_IO) file->f_op = &fuse_direct_io_file_operations; if (!(outarg->open_flags & FOPEN_KEEP_CACHE)) invalidate_inode_pages2(inode->i_mapping); ff->fh = outarg->fh; file->private_data = fuse_file_get(ff); } int fuse_open_common(struct inode *inode, struct file *file, int isdir) { struct fuse_open_out outarg; struct fuse_file *ff; int err; /* VFS checks this, but only _after_ ->open() */ if (file->f_flags & O_DIRECT) return -EINVAL; err = generic_file_open(inode, file); if (err) return err; ff = fuse_file_alloc(); if (!ff) return -ENOMEM; err = fuse_send_open(inode, file, isdir, &outarg); if (err) fuse_file_free(ff); else { if (isdir) outarg.open_flags &= ~FOPEN_DIRECT_IO; fuse_finish_open(inode, file, ff, &outarg); } return err; } void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode) { struct fuse_req *req = ff->reserved_req; struct fuse_release_in *inarg = &req->misc.release.in; inarg->fh = ff->fh; inarg->flags = flags; req->in.h.opcode = opcode; req->in.h.nodeid = nodeid; req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_release_in); req->in.args[0].value = inarg; } int fuse_release_common(struct inode *inode, struct file *file, int isdir) { struct fuse_file *ff = file->private_data; if (ff) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_req *req = ff->reserved_req; fuse_release_fill(ff, get_node_id(inode), file->f_flags, isdir ? FUSE_RELEASEDIR : FUSE_RELEASE); /* Hold vfsmount and dentry until release is finished */ req->misc.release.vfsmount = mntget(file->f_path.mnt); req->misc.release.dentry = dget(file->f_path.dentry); spin_lock(&fc->lock); list_del(&ff->write_entry); spin_unlock(&fc->lock); /* * Normally this will send the RELEASE request, * however if some asynchronous READ or WRITE requests * are outstanding, the sending will be delayed */ fuse_file_put(ff); } /* Return value is ignored by VFS */ return 0; } static int fuse_open(struct inode *inode, struct file *file) { return fuse_open_common(inode, file, 0); } static int fuse_release(struct inode *inode, struct file *file) { return fuse_release_common(inode, file, 0); } /* * 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; 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, struct dentry *de, int datasync, int isdir) { struct inode *inode = de->d_inode; 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; if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir)) return 0; /* * 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) return err; fuse_sync_writes(inode); req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); 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; 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; } return err; } static int fuse_fsync(struct file *file, struct dentry *de, int datasync) { return fuse_fsync_common(file, de, datasync, 0); } void fuse_read_fill(struct fuse_req *req, struct file *file, struct inode *inode, 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 = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(struct fuse_read_in); req->in.args[0].value = inarg; req->out.argpages = 1; 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, struct inode *inode, loff_t pos, size_t count, fl_owner_t owner) { struct fuse_conn *fc = get_fuse_conn(inode); fuse_read_fill(req, file, inode, 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); } 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 liftime 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->num_pages = 1; req->pages[0] = page; num_read = fuse_send_read(req, file, inode, 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 inode *inode = req->pages[0]->mapping->host; /* * Short read means EOF. If file size is larger, truncate it */ if (!req->out.h.error && num_read < count) { loff_t 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); } if (req->ff) fuse_file_put(req->ff); fuse_put_request(fc, req); } static void fuse_send_readpages(struct fuse_req *req, struct file *file, struct inode *inode) { struct fuse_conn *fc = get_fuse_conn(inode); loff_t pos = page_offset(req->pages[0]); size_t count = req->num_pages << PAGE_CACHE_SHIFT; req->out.page_zeroing = 1; fuse_read_fill(req, file, inode, pos, count, FUSE_READ); req->misc.read.attr_ver = fuse_get_attr_version(fc); if (fc->async_read) { struct fuse_file *ff = file->private_data; req->ff = fuse_file_get(ff); req->end = fuse_readpages_end; request_send_background(fc, req); } else { request_send(fc, req); fuse_readpages_end(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, inode); data->req = req = fuse_get_req(fc); if (IS_ERR(req)) { unlock_page(page); return PTR_ERR(req); } } 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, inode); 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 file *file, struct fuse_file *ff, struct inode *inode, loff_t pos, size_t count, int writepage) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_write_in *inarg = &req->misc.write.in; struct fuse_write_out *outarg = &req->misc.write.out; memset(inarg, 0, sizeof(struct fuse_write_in)); inarg->fh = ff->fh; inarg->offset = pos; inarg->size = count; inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0; inarg->flags = file ? file->f_flags : 0; req->in.h.opcode = FUSE_WRITE; req->in.h.nodeid = get_node_id(inode); req->in.argpages = 1; req->in.numargs = 2; if (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, struct inode *inode, loff_t pos, size_t count, fl_owner_t owner) { struct fuse_conn *fc = get_fuse_conn(inode); fuse_write_fill(req, file, file->private_data, inode, pos, count, 0); if (owner != NULL) { struct fuse_write_in *inarg = &req->misc.write.in; inarg->write_flags |= FUSE_WRITE_LOCKOWNER; inarg->lock_owner = fuse_lock_owner_id(fc, owner); } request_send(fc, req); return req->misc.write.out.size; } static int fuse_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { pgoff_t index = pos >> PAGE_CACHE_SHIFT; *pagep = __grab_cache_page(mapping, index); if (!*pagep) return -ENOMEM; return 0; } static 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 int fuse_buffered_write(struct file *file, struct inode *inode, loff_t pos, unsigned count, struct page *page) { int err; size_t nres; struct fuse_conn *fc = get_fuse_conn(inode); unsigned offset = pos & (PAGE_CACHE_SIZE - 1); struct fuse_req *req; if (is_bad_inode(inode)) return -EIO; /* * Make sure writepages on the same page are not mixed up with * plain writes. */ fuse_wait_on_page_writeback(inode, page->index); req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); req->num_pages = 1; req->pages[0] = page; req->page_offset = offset; nres = fuse_send_write(req, file, inode, pos, count, NULL); err = req->out.h.error; fuse_put_request(fc, req); if (!err && !nres) err = -EIO; if (!err) { pos += nres; fuse_write_update_size(inode, pos); if (count == PAGE_CACHE_SIZE) SetPageUptodate(page); } fuse_invalidate_attr(inode); return err ? err : nres; } static int fuse_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = mapping->host; int res = 0; if (copied) res = fuse_buffered_write(file, inode, pos, copied, page); unlock_page(page); page_cache_release(page); return res; } 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, inode, 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->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(mapping, index); if (!page) break; pagefault_disable(); tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); pagefault_enable(); flush_dcache_page(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; } 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; ssize_t written = 0; struct inode *inode = mapping->host; ssize_t err; struct iov_iter i; WARN_ON(iocb->ki_pos != pos); err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ); if (err) return err; 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 = remove_suid(file->f_path.dentry); if (err) goto out; file_update_time(file); 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, unsigned nbytes, int write) { unsigned long user_addr = (unsigned long) buf; unsigned offset = user_addr & ~PAGE_MASK; int npages; /* This doesn't work with nfsd */ if (!current->mm) return -EPERM; nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ); down_read(¤t->mm->mmap_sem); npages = get_user_pages(current, current->mm, user_addr, npages, write, 0, req->pages, NULL); up_read(¤t->mm->mmap_sem); if (npages < 0) return npages; req->num_pages = npages; req->page_offset = offset; return 0; } static ssize_t fuse_direct_io(struct file *file, const char __user *buf, size_t count, loff_t *ppos, int write) { struct inode *inode = file->f_path.dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); size_t nmax = write ? fc->max_write : fc->max_read; loff_t pos = *ppos; ssize_t res = 0; struct fuse_req *req; if (is_bad_inode(inode)) return -EIO; req = fuse_get_req(fc); if (IS_ERR(req)) return PTR_ERR(req); while (count) { size_t nres; size_t nbytes_limit = min(count, nmax); size_t nbytes; int err = fuse_get_user_pages(req, buf, nbytes_limit, !write); if (err) { res = err; break; } nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; nbytes = min(nbytes_limit, nbytes); if (write) nres = fuse_send_write(req, file, inode, pos, nbytes, current->files); else nres = fuse_send_read(req, file, inode, pos, nbytes, current->files); 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; } } fuse_put_request(fc, req); if (res > 0) { if (write) fuse_write_update_size(inode, pos); *ppos = pos; } fuse_invalidate_attr(inode); return res; } static ssize_t fuse_direct_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { return fuse_direct_io(file, buf, count, ppos, 0); } 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; /* Don't allow parallel writes to the same file */ mutex_lock(&inode->i_mutex); res = generic_write_checks(file, ppos, &count, 0); if (!res) res = fuse_direct_io(file, buf, count, ppos, 1); 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); fuse_put_request(fc, req); } 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) { 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++; request_send_background_locked(fc, req); return; out_free: fuse_writepage_finish(fc, req); spin_unlock(&fc->lock); fuse_writepage_free(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) { 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, NULL, ff, inode, page_offset(page), 0, 1); copy_highpage(tmp_page, page); 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 page *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 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 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; 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; /* 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); 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_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_wait(file, fl); 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_lock) { err = flock_lock_file_wait(file, fl); } else { /* emulate flock with POSIX locks */ fl->fl_owner = (fl_owner_t) file; 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; 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; mutex_lock(&inode->i_mutex); switch (origin) { case SEEK_END: offset += i_size_read(inode); break; case SEEK_CUR: offset += file->f_pos; } retval = -EINVAL; if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) { if (offset != file->f_pos) { file->f_pos = offset; file->f_version = 0; } retval = offset; } mutex_unlock(&inode->i_mutex); return retval; } 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, }; static const struct file_operations fuse_direct_io_file_operations = { .llseek = fuse_file_llseek, .read = fuse_direct_read, .write = fuse_direct_write, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, .flock = fuse_file_flock, /* no mmap and splice_read */ }; static const struct address_space_operations fuse_file_aops = { .readpage = fuse_readpage, .writepage = fuse_writepage, .launder_page = fuse_launder_page, .write_begin = fuse_write_begin, .write_end = fuse_write_end, .readpages = fuse_readpages, .set_page_dirty = __set_page_dirty_nobuffers, .bmap = fuse_bmap, }; void fuse_init_file_inode(struct inode *inode) { inode->i_fop = &fuse_file_operations; inode->i_data.a_ops = &fuse_file_aops; }