* When repairing multiple chunks at once and any of its repair
failed, the whole read request and repair work will fail
* Rename read_repair3 and read_repair4 to do_repair_chunks and
do_repair chunk in machi_file_proxy
* This pull request changes return semantics of read_chunk(), that
returns any chunk included in requested range
* First and last chunk may be cut to fit the requested range
* In machi_file_proxy, unwritten_bytes are removed and replaced by
machi_csum_table
This is simply a change of read_chunk() protocol, where a response of
read_chunk() becomes list of written bytes along with checksum. All
related code including repair is changed as such. This is to pass all
tests and not actually supporting partial chunks.
For debuging from shell, some functions in machi_cinfo are exported:
- public_projection/1
- private_projection/1
- fitness/1
- chain_manager/1
- flu1/1
The FLU psup starts the chain manager in active mode by default
(as it should for normal run-time operation.) By adding the
{active_mode, false} tuple to the options list, we can
tell the chain manager that it should be explicitly manipulated
during tests.
I am treating the original write-once branch as a prototype
which I am now throwing away. I had too much work interleved
in there, so I felt like the best thing to do would be to cut
a new clean branch and pull the files over and start over
against a recent-ish master.
We will have to refactor the other things in FLU in a more
piecemeal fashion.
Last night we hit a rare case of failed convergence.
f was out of sync with the rest of the world.
f: upi=[b,g,f] repairing=[a,c]
The "rest of the world" used a larger chain at:
*: upi=[c,b,g,a], repairing=[f]
And f refused to join the larger chain because of the way that
IsRelevantToMe_p was being calculated before this commit.
Hrrrm, though, I'm not convinced that this particular problem
is fixed 100% by this patch. What if the chain lengths were
the same but also UPI incompatible? e.g. if I remove 'a' from
the "real world (in the partition simulator)" example above:
f: upi=[b,g,f] repairing=[c]
*: upi=[c,b,g], repairing=[f]
Hrmmmmm, I may need to reintroduce the my-recent-adopted-projection-
flapping-like-counter thingie to try to break this kind of
incompatible deadlock.
