fs/file_table.c:377:22: error: implicit declaration of function 'real_mount'; did you mean 'kern_mount'? [-Werror=implicit-function-declaration] fs/file_table.c:378:16: error: implicit declaration of function 'mnt_get_count'; did you mean 'init_page_count'? [-Werror=implicit-function-declaration] fs/file_table.c:380:13: error: invalid use of undefined type 'struct mount'