RFR: 8232861: (fc) FileChannel.force fails on WebDAV file systems (macOS) [v2]

[Alan Bateman]

On Wed, 7 Apr 2021 16:51:26 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> src/java.base/unix/native/libnio/ch/FileDispatcherImpl.c line 184:
>> 
>>> 182:                 result = fsync(fd);
>>> 183:             }
>>> 184:         }
>> 
>> Do you need to save/restore errno so that the original error from fcntl(F_FULLSYNC) is used in the error handling?
>> 
>> Also what you would think about dropping the check for ENOTSUP.
>
> I thought about `errno` but didn't know whether it's common practice to cache it like that.
> 
> We had `ENOTSUP` I suppose in case the `F_FULLSYNC` is unsupported on a local file system. From the man page of `fcntl()` the doc of `F_FULLSYNC` states
> This is currently implemented on HFS, MS-DOS (FAT), Universal Disk Format (UDF) and APFS file systems
> although `ENOTSUP` itself is not actually documented here.

I think this looks good, I'm just wondering to myself if it is possible to get ENOTSUP from a local device.

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PR: https://git.openjdk.java.net/jdk/pull/3366