We have an XFS volume mounted on RHEL9.5 (5.14.0-503.22.1.el9_5.x86_64) with only 88K files on it:
$ find /mnt -type f | wc -l
87739
The file system reports ~200GB of free space. However, the total - real used gives ~4TB.
$ df /mnt
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 558602657792 558397210232 205447560 100% /mnt
$ du -s /mnt
554502450484 /mnt
The difference between filesystem total size and the sum of file sizes
558602657792 - 554502450484
4100207308
Where is the lost space, and how can we reclaim it? As suggested by other answers, we have tried xfs_fsr and xfs_repair, but nothing has changed.