samba - Mar 2022 - ZFS and vfs_shadow_copy2

On 2/17/22 17:33, Adam Thorn via samba wrote:
> I've tcpdumped on the samba server at the point I right click the 
> "Restore previous versions.." option on my Win10 client, and then
viewed
> the pcap in wireshark. I see my client sending a 
> FSCTL_SRV_ENUMERATE_SNAPSHOTS request, and then in the server reply I 
> look at the "Ioctl Response" part of the smb payload. That
response
> includes "Out data" looking like...
> 
> Number of snapshots: 19
> Snapshot: @GMT-2022.02.17-12.54.03
> Snapshot: @GMT-2022.02.17-06.54.03
> (etc etc)
> 
> The list of snapshots in the pcap matches what I expect based on running 
> zfs list -r -t snapshot -oname, and all of the snapshots display as 
> expected in the Windows previous version client.
Hello.

I finally had the chance to do this test.
The packet trace shows all the ZFS snapshots I expected, but Windows (10 
or 11) will only list the most recent.

At least now I know it's a client side problem.

  bye & Thanks
	av.

On 3/23/22 13:52, Andrea Venturoli via samba wrote:
> At least now I know it's a client side problem.
After further investigation, maybe not.

I'm still looking into this, but it seems to be a problem with time 
conversion.



I have:
> root at fs:~ # date -u
> Wed Mar 23 14:46:22 UTC 2022
> root at fs:~ # date
> Wed Mar 23 15:46:23 CET 2022
(kernel clock set to UTC time).


> # zfs list -t snap
> zroot/ezjail/fs/shares at auto_zroot-20210920080000       95.9K      -  
117K  -
 > ...

080000 is my local time (not UTC).

So, as per VFS_SHADOW_COPY2(8), I put "shadow:localtime=yes" in
smb.conf.



For the above, the packet trace shows the following in the list:
Snapshot: @GMT-2021.09.20-06.00.00

Seems right, as locat time was converted to UTC.


However, after receiving such a list, the client tries to probe some of 
the snapshots, e.g.:
> Create Request File: @Sep 20, 2021 06:00:00.000000000
and the server obviously answers:
> NT Status: STATUS_UNSUCCESSFUL (0xc0000001)
Possibly this is the reason a wider range (long time ago, this year, 
last month, etc...) is excluded.



I have yet to test this in the wild, but putting "shadow:localtime=no"
allowed me to see the full list.
Of course all the snapshots are labeled as one hour later (the last 
being in the future).

Any hint?
Is this a bug or feature?

  bye & Thanks
	av.