[Samba] vfs_shadow_copy2 cannot read/find snapshots

[Sebastian Neustein]

The gluster side looks like this:

root at B741:~# gluster volume get glvol_samba features.show-snapshot-directory
features.show-snapshot-directory         on

root at B741:~# gluster volume get glvol_samba features.uss
features.uss                             enable


I found an error when the samba client is mounting the gluster volume in 
the gluster logs (/var/log/glusterfs/snaps/glvol_samba/snapd.log)
[2023-05-22 12:52:09.438169 +0000] E 
[server-handshake.c:156:server_first_lookup] 0-snapd-glvol_samba: lookup 
on root failed: argument is not valid
(the last bit of the error message is translated from German, might be a 
bit different though, original version is: Das Argument ist ungültig)


Am 22.05.2023 um 14:46 schrieb Sebastian Neustein:
> Hi
>
> I am trying to get shadow_copy2 to read gluster snapshots and provide 
> the users with previous versions of their files.
>
> Here is my smb.conf:
>
> [global]
>         security = ADS
>         workgroup = AD
>         realm = AD.XXX.XX
>         netbios name = A32X
>         log file = /var/log/samba/%m
>         log level = 1
>         idmap config * : backend = tdb
>         idmap config * : range = 10000-10100
>         idmap config AD:backend = rid
>         idmap config AD:range = 1000000-1999999
>         vfs objects = acl_xattr
>         map acl inherit = yes
>         inherit acls = yes
>         store dos attributes = yes
>         winbind use default domain = yes
>
> [admin]
>         path = /srv/glvol_samba/admin
>         guest ok = no
>         read only = no
>         browseable = no
>         administrative share = yes
>         vfs objects = acl_xattr glusterfs_fuse
>
> [projects]
>         path = /srv/glvol_samba/admin/projects
>         comment = ARC Projekte
>         guest ok = no
>         read only = no
>         shadow:snapdir = /srv/glvol_samba/admin/projects/.snaps
>         shadow:basedir = /srv/glvol_samba/admin/projects
>         shadow:sort = desc
>         shadow:snapprefix = ^snap$
>         shadow:format = _GMT-%Y.%m.%d-%H.%M.%S
>         vfs objects = acl_xattr shadow_copy2 glusterfs_fuse
>
>
> I can go to a shared directory on the samba server and enter the 
> .snaps subdirectory, in there I can see:
>
> root at XXX:~# cd /srv/glvol_samba/admin/projects/.snaps
>
> root at XXX:/srv/glvol_samba/admin/projects/.snaps# ls -ld
> drwxr-xr-x 2 root root 4096  1. Jan 1970  .
>
> root at XXX:/srv/glvol_samba/admin/projects/.snaps# ls -l
> insgesamt 28
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.16-19.14.01
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.17-19.14.01
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.18-19.14.01
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.19-19.14.01
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.20-19.14.01
> drwxrwx---+ 3 domadmin.sn domänen-benutzer 4096 16. Mai 16:31 
> snap_GMT-2023.05.21-19.14.01
>
> Until here, from my point of view, everything works as expected.
>
> But when I try to access a previous version of a file from a windows 
> client, samba logs:
> [2023/05/22 10:39:52.278407,  1] 
> ../../source3/modules/vfs_shadow_copy2.c:2222(shadow_copy2_get_shadow_copy_data)
>   shadow_copy2_get_shadow_copy_data: SMB_VFS_NEXT_OPEN failed for 
> '/srv/glvol_samba/admin/projects/.snaps' - Permission denied
> Even though the file has changed, the user cannot see a previous 
> version. The list is empty.
>
> I can mount a single snapshot on a linux client into /mnt and see all 
> files as expected:
> root at YYY:~# mount.glusterfs 
> B741:/snaps/snap_GMT-2023.05.21-19.14.01/glvol_samba /mnt/
>
> On the samba server the gluster share is mounted with:
> root at XXX:~# mount -t fuse.glusterfs
> B741:/glvol_samba on /srv/glvol_samba type fuse.glusterfs 
> (rw,relatime,user_id=0,group_id=0,allow_other,max_read=131072,_netdev)
>
> The systemd unit for this is:
> root at XXX:~# cat /etc/systemd/system/srv-glvol_samba.mount
> [Unit]
> Description=Data Dir
> After=network.target
> Requires=network-online.target
>
> [Mount]
> What=B741:/glvol_samba
> Where=/srv/glvol_samba
> Type=glusterfs
> Options=defaults,_netdev,negative-timeout=10,attribute-timeout=30,fopen-keep-cache,direct-io-mode=enable,acl
>
> [Install]
> WantedBy=multi-user.target
>
>
> The OS is debian 11.7 with sernet samba packages (4.17.8).
>
> Regards
> Sebastian
> -- 
> Sebastian Neustein
>
> Airport Research Center GmbH
> Bismarckstraße 61
> 52066 Aachen
> Germany
>
> Phone: +49 241 16843-23
> Fax: +49 241 16843-19
> e-mail:sebastian.neustein at arc-aachen.de
> Website:http://www.airport-consultants.com
>
> Register Court: Amtsgericht Aachen HRB 7313
> Ust-Id-No.: DE196450052
>
> Managing Director:
> Dipl.-Ing. Tom Alexander Heuer

-- 
Sebastian Neustein

Airport Research Center GmbH
Bismarckstraße 61
52066 Aachen
Germany

Phone: +49 241 16843-23
Fax: +49 241 16843-19
e-mail:sebastian.neustein at arc-aachen.de
Website:http://www.airport-consultants.com

Register Court: Amtsgericht Aachen HRB 7313
Ust-Id-No.: DE196450052

Managing Director:
Dipl.-Ing. Tom Alexander Heuer