[crac] RFR: Handle open file descriptors with configurable policies [v3]

[Anton Kozlov]

On Fri, 9 Jun 2023 10:16:02 GMT, Radim Vansa <duke at openjdk.org> wrote:

>> I've started with a single policy enum but it turned out the inlined cross product of behaviours was rather a long and repetitive.
>> In fact CLOSE + REOPEN is the combination that makes a perfect sense. You close the file on checkpoint (rather than error out and fail the checkpoint) and then you reopen the same file (rather than opening something else).
>
> And note that the restore configuration should be set on restore, because in case of opening other files you don't know where these are in the deployment (restore) environment during checkpoint. Had you specified the policy together you would be overriding the behaviour on checkpoint which was already executed, which is even more confusing.

> I've started with a single policy enum but it turned out the inlined cross product of behaviours was rather a long and repetitive.

Do you have artifacts of that? Because it may mean that cross-product may have a few invalid / unsafe behaviors. It would be interesting to look at the list.

> In fact CLOSE + REOPEN is the combination that makes a perfect sense. 

Indeed, bad example. What about ERROR+OPEN_OTHER. Or for the sockets, for the current implementation we should not allow OPEN_OTHER, as the implementation can only throw RestoreException in this case.

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PR Review Comment: https://git.openjdk.org/crac/pull/69#discussion_r1224457914