samba - Nov 2024 - Random EINVAL when opening files with SMB3 POSIX extensions enabled

On 11/26/24 11:03 PM, Andrew Gunnerson via samba wrote:
> I recently tried enabling SMB3 POSIX extensions as I'm only using Linux
clients
> and would like to make use of the standard unix permission bits. However,
I'm
> running into an issue where a simple `cat` fails with -EINVAL when opening
the
> file:
> 
>      openat(AT_FDCWD, "Shells.txt", O_RDONLY) = -1 EINVAL
(Invalid argument)
> 
> The weird thing is that it's intermittent. It'll fail with EINVAL
many times in
> a row and then suddenly work and then start failing again.
can you grab a network trace when it happens?

<https://wiki.samba.org/index.php/Capture_Packets#Tracing_SMB_traffic_of_a_specific_client>

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.

-slow

-- 
SerNet Samba Team Lead https://sernet.de/
Samba Team Member      https://samba.org/
SAMBA+ packages       https://samba.plus/
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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