static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
			     void *dstbuf, filldir_t filldir, u64 attr_version)
{
	struct fuse_direntplus *direntplus;
	struct fuse_dirent *dirent;
	size_t reclen;
	int over = 0;
	int ret;

	while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
		direntplus = (struct fuse_direntplus *) buf;
		dirent = &direntplus->dirent;
		reclen = FUSE_DIRENTPLUS_SIZE(direntplus);

		if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
			return -EIO;
		if (reclen > nbytes)
			break;
		if (memchr(dirent->name, '/', dirent->namelen) != NULL)
			return -EIO;

		if (!over) {
			/* We fill entries into dstbuf only as much as
			   it can hold. But we still continue iterating
			   over remaining entries to link them. If not,
			   we need to send a FORGET for each of those
			   which we did not link.
			*/
			over = filldir(dstbuf, dirent->name, dirent->namelen,
				       file->f_pos, dirent->ino,
				       dirent->type);
			file->f_pos = dirent->off;
		}

		buf += reclen;
		nbytes -= reclen;

		ret = fuse_direntplus_link(file, direntplus, attr_version);
		if (ret)
			fuse_force_forget(file, direntplus->entry_out.nodeid);
	}

	return 0;
}
Exemplo n.º 2
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static int fuse_direntplus_link(struct file *file,
				struct fuse_direntplus *direntplus,
				u64 attr_version)
{
	int err;
	struct fuse_entry_out *o = &direntplus->entry_out;
	struct fuse_dirent *dirent = &direntplus->dirent;
	struct dentry *parent = file->f_path.dentry;
	struct qstr name = { .len = dirent->namelen, .name = dirent->name };
	struct dentry *dentry;
	struct dentry *alias;
	struct inode *dir = parent->d_inode;
	struct fuse_conn *fc;
	struct inode *inode;

	if (!o->nodeid) {
		/*
		 * Unlike in the case of fuse_lookup, zero nodeid does not mean
		 * ENOENT. Instead, it only means the userspace filesystem did
		 * not want to return attributes/handle for this entry.
		 *
		 * So do nothing.
		 */
		return 0;
	}

	if (name.name[0] == '.') {
		/*
		 * We could potentially refresh the attributes of the directory
		 * and its parent?
		 */
		if (name.len == 1)
			return 0;
		if (name.name[1] == '.' && name.len == 2)
			return 0;
	}

	if (invalid_nodeid(o->nodeid))
		return -EIO;
	if (!fuse_valid_type(o->attr.mode))
		return -EIO;

	fc = get_fuse_conn(dir);

	name.hash = full_name_hash(name.name, name.len);
	dentry = d_lookup(parent, &name);
	if (dentry) {
		inode = dentry->d_inode;
		if (!inode) {
			d_drop(dentry);
		} else if (get_node_id(inode) != o->nodeid ||
			   ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
			err = d_invalidate(dentry);
			if (err)
				goto out;
		} else if (is_bad_inode(inode)) {
			err = -EIO;
			goto out;
		} else {
			struct fuse_inode *fi;
			fi = get_fuse_inode(inode);
			spin_lock(&fc->lock);
			fi->nlookup++;
			spin_unlock(&fc->lock);

			fuse_change_attributes(inode, &o->attr,
					       entry_attr_timeout(o),
					       attr_version);

			/*
			 * The other branch to 'found' comes via fuse_iget()
			 * which bumps nlookup inside
			 */
			goto found;
		}
		dput(dentry);
	}

	dentry = d_alloc(parent, &name);
	err = -ENOMEM;
	if (!dentry)
		goto out;
	dentry->d_op = &fuse_dentry_operations;

	inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
			  &o->attr, entry_attr_timeout(o), attr_version);
	if (!inode)
		goto out;

	alias = fuse_materialise_dentry(dentry, inode);
	err = PTR_ERR(alias);
	if (IS_ERR(alias))
		goto out;

	if (alias) {
		dput(dentry);
		dentry = alias;
	}

found:
	fuse_change_entry_timeout(dentry, o);

	err = 0;
out:
	dput(dentry);
	return err;
}

static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
			     void *dstbuf, filldir_t filldir, u64 attr_version)
{
	struct fuse_direntplus *direntplus;
	struct fuse_dirent *dirent;
	size_t reclen;
	int over = 0;
	int ret;

	while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
		direntplus = (struct fuse_direntplus *) buf;
		dirent = &direntplus->dirent;
		reclen = FUSE_DIRENTPLUS_SIZE(direntplus);

		if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
			return -EIO;
		if (reclen > nbytes)
			break;
		if (memchr(dirent->name, '/', dirent->namelen) != NULL)
			return -EIO;

		if (!over) {
			/* We fill entries into dstbuf only as much as
			   it can hold. But we still continue iterating
			   over remaining entries to link them. If not,
			   we need to send a FORGET for each of those
			   which we did not link.
			*/
			over = filldir(dstbuf, dirent->name, dirent->namelen,
				       file->f_pos, dirent->ino,
				       dirent->type);
			file->f_pos = dirent->off;
		}

		buf += reclen;
		nbytes -= reclen;

		ret = fuse_direntplus_link(file, direntplus, attr_version);
		if (ret)
			fuse_force_forget(file, direntplus->entry_out.nodeid);
	}

	return 0;
}

static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
{
	int plus, err;
	size_t nbytes;
	struct page *page;
	struct inode *inode = file->f_path.dentry->d_inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	u64 attr_version = 0;

	if (is_bad_inode(inode))
		return -EIO;

	req = fuse_get_req(fc, 1);
	if (IS_ERR(req))
		return PTR_ERR(req);

	page = alloc_page(GFP_KERNEL);
	if (!page) {
		fuse_put_request(fc, req);
		return -ENOMEM;
	}

	plus = fuse_use_readdirplus(inode, file);
	req->out.argpages = 1;
	req->num_pages = 1;
	req->pages[0] = page;
	req->page_descs[0].length = PAGE_SIZE;
	if (plus) {
		attr_version = fuse_get_attr_version(fc);
		fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,
			       FUSE_READDIRPLUS);
	} else {
		fuse_read_fill(req, file, file->f_pos, PAGE_SIZE,
			       FUSE_READDIR);
	}
	fuse_request_send(fc, req);
	nbytes = req->out.args[0].size;
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (!err) {
		if (plus) {
			err = parse_dirplusfile(page_address(page), nbytes,
						file, dstbuf, filldir,
						attr_version);
		} else {
			err = parse_dirfile(page_address(page), nbytes, file,
					    dstbuf, filldir);
		}
	}

	__free_page(page);
	fuse_invalidate_attr(inode); /* atime changed */
	return err;
}