Reading >4kB xattrs (from ZFS) = input/output error

[pb+samba at Arkthis.com]

Hi everyone :)

I've recently set a >40kB binary metadata as xattrs on ZFS, using 
`setfattr` locally.
Works fine, and I can read/write data like that without issues.

But when I try to access such "larger" xattrs over Samba using 
`getfattr`, I get the following error:

`getfattr: bigdata.test: Input/output error`

I've tried increasing the log-level on the server's smb.conf, but I 
couldn't make out relevant information telling me more about this.


The server's running Samba packed from Ubuntu (18.04): 
2:4.7.6+dfsg~ubuntu-0ubuntu2.29

I know that version's ancient, but it's a stable (in-house) production 
server.
What is the limit of Samba's support for xattrs, and is there anything I 
can do about this? (I've read all I could find on xattrs and smb.conf)


Thank you very much in advance for any insights :)
Peter