8227609: (fs) Files.newInputStream(...).skip(n) should allow skipping beyond file size

[Florian Weimer]

* Brian Burkhalter:

>  On Jul 26, 2019, at 7:53 AM, Brian Burkhalter <brian.burkhalter at oracle.com> wrote:
>
>  I saw a test failure in the CI system with this:
> ----------System.err:(18/1120)----------
> java.io.IOException: Invalid argument
> 	at java.base/sun.nio.ch.FileDispatcherImpl.seek0(Native Method)
> 	at java.base/sun.nio.ch.FileDispatcherImpl.seek(FileDispatcherImpl.java:78)
> 	at java.base/sun.nio.ch.FileChannelImpl.position(FileChannelImpl.java:361)
> 	at java.base/sun.nio.ch.FileChannelImpl.position(FileChannelImpl.java:52)
> 	at java.base/sun.nio.ch.ChannelInputStream.skip(ChannelInputStream.java:132)
> 	at InputStreamTest.testSkip(InputStreamTest.java:115)
>  InputStreamTest.java;
>  112                 assertTrue(in.skip(size/2) == size/2); // 0.5
>  113                 assertTrue(in.available() == size/2);
>  114 
>  115                 assertTrue(in.skip(Long.MAX_VALUE - size/4) ==
>  116                     Long.MAX_VALUE - size/2);
>  117                 assertTrue(in.available() == 0);
>  It looks as if for some case lseek64() doesn’t like an argument of Long.MAX_VALUE. I’ll need to run this down before checking
>  anything in.
>
> This was on Linux-x64.

On ext4?  The EINVAL depends on the file system.  XFS supports arbitrary
offsets, but ext4 does not, for example.

We discussed this recently on another thread:

From: Karan Mehta <k.mehta at salesforce.com>
Date: Tue, 4 Jun 2019 10:13:05 -0700
Subject: Invalid argument exception when trying to seek FilePosition to
 LONG.MAX_VALUE
To: nio-dev at openjdk.java.net
Message-ID: <CANpNY381LM5XRd2GCc93V1sDuc4JoDoctv83Ur75XfhoGPvF=w at mail.gmail.com>

Thanks,
Florian