* Fix FUSE server buffer leaks in file gaps
This change zeros read buffers when encountering file gaps during
file/chunk reads in FUSE mounts.
It prevents leaking internal buffers of the FUSE server which could
otherwise reveal metadata, directory listings, file contents and
other data related to FUSE API calls.
The issue was that buffers are reused, but when a file gap was found
the buffer was not zeroed accordingly and the existing data of the
buffer was kept and returned.
* Move zero logic into its own method
3f758820c1