Christopher Haster 745d98cde0 Fixed lfs_file_truncate issue where internal state may not be flushed
This was caused by the new lfs_file_rawseek optimization that can skip
flushing when calculated file->pos is unchanged combined with an
implicit expectation in lfs_file_truncate that lfs_file_rawseek
unconditionally sets file->pos.

Because of this assumption, lfs_file_truncate could leave file->pos in
an outdated state while changing the internal file metadata. Humorously,
this was always gauranteed to trigger the skip in lfs_file_rawseek when
we try to restore the file->pos, leaving the file->cache used to do the
CTZ skip-list lookup in a potentially bad state.

The easiest fix is to just update file->pos correctly. Note we don't
want to explicitly flush since we can leverage the same noop
optimization if we truncate to the file position. Which I've added a
test for.
2021-01-11 00:14:34 -06:00
..