new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ubifs/file.c

@@ -1444,7 +1444,7 @@ static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma,
 				 struct vm_fault *vmf)
 {
 	struct page *page = vmf->page;
-	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+	struct inode *inode = file_inode(vma->vm_file);
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 	struct timespec now = ubifs_current_time(inode);
 	struct ubifs_budget_req req = { .new_page = 1 };