RFR: 8293004: (fs) copy_file_range needs fallback handling for ENOSYS

[Thomas Stüfe]

Hi Florian,

do I understand this correctly: by backporting the user-space emulation for
copy_file_range, glibc 2.27 broke compatibility with kernels < 4.5?

If yes, why did glibc not retain the emulation for the ENOSYS case?

Cheers, Thomas

On Sat, Aug 27, 2022 at 12:20 PM Florian Weimer <fweimer at openjdk.org> wrote:

> Now that the userspace emulation is not leveraged anymore, it would be
> possible to issue the system call directly for all glibc versions, but it's
> probably best not to start using `copy_file_range` where it hasn't been
> used before (the el7 kernel has a strange backport, if I recall correctly).
>
> -------------
>
> Commit messages:
>  - 8293004: (fs) copy_file_range needs fallback handling for ENOSYS
>
> Changes: https://git.openjdk.org/jdk/pull/10055/files
>  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10055&range=00
>   Issue: https://bugs.openjdk.org/browse/JDK-8293004
>   Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
>   Patch: https://git.openjdk.org/jdk/pull/10055.diff
>   Fetch: git fetch https://git.openjdk.org/jdk pull/10055/head:pull/10055
>
> PR: https://git.openjdk.org/jdk/pull/10055
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/nio-dev/attachments/20220827/9a16fc4e/attachment.htm>