Invalid journal entries? That's the thing... there is no journal in ext2, it is not a journaling filesystem so it is error prone. ext3 = ext2 + journal
Convert to ext3 then, and change U-Boot parameter "usb_rootfstype" to ext3 before you convert.
$this->bbcode_second_pass_code('', 'pacman -Sy uboot-env
fw_setenv usb_rootfstype 'ext3'')
then shutdown your plug "gracefully"
Plugin your stick/hdd to another linux machine and issue
$this->bbcode_second_pass_code('', 'tune2fs -j /dev/sdX1')
replace X with the appropriate drive letter