https://blogs.oracle.com/linux/post/oracle-is-the-1-contribu...
XFS is really important for (their) database performance, so quite a lot comes out of Oracle for it. You might also know that btrfs began at Oracle.
https://www.google.com/search?q=oracle+blog+xfs
https://en.wikipedia.org/wiki/Btrfs
"Chris Mason, an engineer working on ReiserFS for SUSE at the time, joined Oracle later that year and began work on a new file system based on these B-trees."