[Samba] Random EINVAL when opening files with SMB3 POSIX extensions enabled

[Andrew Gunnerson]

Thanks for the replies!

On Thu, Nov 28, 2024, at 04:34, Rowland Penny via samba wrote:
> I do not use the SMB3 Unix extensions, but perhaps you may not be
> either, have you tried replacing 'server min protocol = SMB2' (which is
> the default anyway) with 'server min protocol = SMB3' ?

I took a packet capture and do see the the client making POSIX extension
requests, like SMB2_FILE_POSIX_INFO.

On Thu, Nov 28, 2024, at 04:53, Ralph Boehme wrote:
> can you grab a network trace when it happens?

Sure thing! I disabled SMB encryption first since it seemed to make the pcaps
useless.

1. pcap when running `cat <file>`, which fails with EINVAL:

    https://files.pub.chiller3.com/issues/samba/posix_extensions/2024-11-28/posix_enabled_broken.pcap

2. pcap when running `ls $(dirname <file>); cat <file>`, which seems to
   temporarily (but consistently) allow the file to be opened for a short time:

    https://files.pub.chiller3.com/issues/samba/posix_extensions/2024-11-28/posix_enabled_working.pcap

3. pcap when running `cat <file>` with the extensions disabled, which always
   works:

    https://files.pub.chiller3.com/issues/samba/posix_extensions/2024-11-28/posix_disabled_working.pcap

> Beware that SMB3 POSIX Extensions are still under active development and 
> I would recommend not using them in production right now because of bugs 
> in Samba and cifs.ko.

That's good to know. In my case, I'm mostly playing around with things on my
personal systems and don't care if anything breaks or data gets corrupted. Happy
to help test things!

-Andrew