RFR: 8293122: (fs) Use file cloning in macOS version of Files::copy method [v2]

[Alan Bateman]

On Wed, 7 Sep 2022 00:51:40 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8293122: Revert BsdFileStore; move volume capability check to BsdNativeDispatcher
>
> src/java.base/macosx/classes/sun/nio/fs/BsdFileSystem.java line 110:
> 
>> 108:             switch (x.errno()) {
>> 109:                 case ENOTSUP: // cloning not supported by filesystem
>> 110:                     return IOStatus.UNSUPPORTED;
> 
> It might be that `ENOTSUP` should instead result in `UNSUPPORTED_CASE` and that the static variable `cloneFileNotSupported` is unnecessary.

Yes, ENOTSUP depends on the parameters to I think it maps to UNSUPPORTED_CASE. Given that it has to handle ENOTSUP then it may be that the check for the VOL_CAP_INT_CLONE feature isn't needed. You may have to compare to the performance of getattrlist to see if it helps when the file systems don't support clone.

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PR: https://git.openjdk.org/jdk/pull/10188