Maybe it would be better to track upstream spiffs. I don't know
whether the
spiffs implementation in NuttX requires any changes from upstream but
if so
maybe they can be upstreamed as well.
Not compatible. The NuttX version was a major re-implementation with
major changes. The original worked on bare metal. Even just
following the NuttX coding standard makes code difficult to consider
updating or upstreaming.
At the time the code was leveraged into NuttX. The SPIFFS project had
been idle for many months and appeared to be an abandoned, dead
project. Some months after the NuttX port, the project came back to
life in order to add security features to the file system.
The policy in the past was that no active projects could come into the
NuttX source tree for just this reason. SPIFFS would not be there if it
did not appear to be inactive. The corollary to that policy is that
when code comes into the source tree, it is frozen and forked from the
original with no possibility of simple updates.