16 Dec
2017
16 Dec
'17
11:11 p.m.
Hi Randy,
One way the kernel could tell old from new inodes is
by reserving the
high bit of one of the current 32-bit fields
When Doug mentioned the high bit being an escape I assumed something
like, using eight bits for ease,
00-7f existing positive meaning
80-df new meaning as if unsigned
e0-ff existing negative meaning
existing 80 81...df e0...fe ff 00 01...7f
new e0...fe ff 00 01...7f 80 81..df
This would extend the positive range beyond 2038, but keep a small range
of negatives for their existing pre-1970 meaning. This is storage
representation. Calculations can be done in a wider int, with
intermediate values simply being signed, as before.
--
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy