Interpreting fsck_hfs result

While trying to understand why my Mac stopped performing so well on Spotlight.. I tried a suggestion that had me check my HD's status on Disk Utility. I can't press the Unmount button even after using First-Aid, weird. So this led me to searching this link - an old one but informative - and tried the commands there. For the two other commands I got the expected result. Using sudo fsck_hfs -f /dev/disk0s2 or -fy, however.. (-y for Always attempt to repair any damage that is found ) while this is expected: I got the following result. Same when typed -f in place of -fy. This seemed troublesome. But shame I don't have a clue what is the issue nor how to deal with it. Could anyone share some insight please?