RFR: 8262844: FileStore.supportsFileAttributeView might return false negative in case of ext3

[Brian Burkhalter]

On Tue, 2 Mar 2021 23:36:03 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> @bplb Would you have cycles to look at this one? We've always tried to reduce the probing on the mount points but this one means we will probe ext3 systems. I can't quire tell if this is something specific to SuSE or whether other distributions enable it too.
>
> Apparently as of version 11-SP3, the default file system of SLES was changed to Ext3 [1]. In [2] it is stated that
> 
> "The default inode size of ext3 file systems has been increased from 128 bytes to 256 bytes on SLES11, because of extended attributes / ACLs."
> 
> From this it may be inferred that extended attributes are enabled by default from SLES 11. One may therefore suppose that the kernel was built with configuration item CONFIG_EXT3_FS_XATTR set to Y [3].
> 
> [1] https://www.suse.com/releasenotes/x86_64/SUSE-SLES/11-SP3/, section 6.8
> [2] https://www.suse.com/support/kb/doc/?id=000017683
> [3] https://cateee.net/lkddb/web-lkddb/EXT3_FS_XATTR.html

Based on testing it looks like xattr is enabled by default for ext3 file systems in Ubuntu 18.04 LTS (Linux kernel 4.15.0).

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PR: https://git.openjdk.java.net/jdk/pull/2778