O Gparted deve ter feito um formato "preguiçoso" mais rápido do novo espaço ext4, e agora, ao montar, está finalizando o trabalho. Essas opções de mke2fs
devem explicar:
lazy_itable_init[= <0 to disable, 1 to enable>]
If enabled and the uninit_bg feature is enabled, the
inode table will not be fully initialized by mke2fs.
This speeds up filesystem initialization noticeably, but
it requires the kernel to finish initializing the
filesystem in the background when the filesystem is
first mounted. If the option value is omitted, it
defaults to 1 to enable lazy inode table zeroing.
lazy_journal_init[= <0 to disable, 1 to enable>]
If enabled, the journal inode will not be fully zeroed
out by mke2fs. This speeds up filesystem initialization
noticeably, but carries some small risk if the system
crashes before the journal has been overwritten entirely
one time. If the option value is omitted, it defaults
to 1 to enable lazy journal inode zeroing.