illumos gate

The parent directory ".." of the top-level of an SMB share served by Illumos kernel appears as a plain file to clients.
This prevents Windows clients from copying the user profile at login, if the profile directory is the top-level of an SMB share served by an Illumos kernel.
This issue can be observed by:

# zfs create rpool/smbtest
# zfs set sharesmb=on rpool/smbtest
# share -F smb
c$@smb          /var/smb/cvol   ""   "" 
rpool_smbtest@  /rpool/smbtest   ""   "" 
# smbadm list | head -1
[*] [MATH602]
# smbclient  -U MATH602\\nakano '\\localhost\rpool_smbtest'
Password for [MATH602\nakano]:
Try "help" to get a list of possible commands.
smb: \> ls
  .                                  DA        0  Fri Sep  8 15:06:30 2023
  ..                                           0  Thu Jan  1 09:00:00 1970

                2605433 blocks of size 131072. 2605432 blocks available
smb: \> exit

The test environment is as follows:

# uname -rvimp
5.11 illumos-96d99ca952 i86pc i386 i86pc
# pkg verify service/file-system/smb
# pkg info service/file-system/smb
             Name: service/file-system/smb
          Summary: SMB Server
      Description: SMB Server libraries and commands
         Category: System/File System
            State: Installed
        Publisher: openindiana.org
          Version: 0.5.11
           Branch: 2023.0.0.21799
   Packaging Date: Wed Sep  6 01:10:13 2023
Last Install Time: Sun Oct 31 19:39:21 2021
 Last Update Time: Wed Sep  6 06:12:37 2023
             Size: 3.36 MB
             FMRI: pkg://openindiana.org/service/file-system/smb@0.5.11-2023.0.0.21799:20230906T011013Z
# zfs get version rpool
NAME   PROPERTY  VALUE    SOURCE
rpool  version   5
# zpool get version rpool
NAME   PROPERTY  VALUE    SOURCE
rpool  version   28       local
# sharectl get smb
system_comment=
max_workers=1024
netbios_enable=false
netbios_scope=
lmauth_level=4
keep_alive=0
wins_server_1=
wins_server_2=
wins_exclude=
signing_enabled=true
signing_required=true
restrict_anonymous=false
pdc=
ads_site=
ddns_enable=false
autohome_map=/etc
ipv6_enable=false
print_enable=false
traverse_mounts=true
map=
unmap=
disposition=
min_protocol=
max_protocol=
encrypt=disabled
encrypt_ciphers=
bypass_traverse_checking=true
oplock_enable=true
short_names=true

Perhaps, a patch like the following would be needed to usr/src/uts/common/fs/smbsrv/smb_vops.c.

diff -c usr/src/uts/common/fs/smbsrv/smb_vops.c.ORG usr/src/uts/common/fs/smbsrv/smb_vops.c
*** usr/src/uts/common/fs/smbsrv/smb_vops.c.ORG Mon Sep  4 16:55:54 2023
--- usr/src/uts/common/fs/smbsrv/smb_vops.c     Fri Sep  8 15:51:15 2023
***************
*** 686,691 ****
--- 686,696 ----
                if (rootvp && (dvp == rootvp)) {
                        VN_HOLD(dvp);
                        *vpp = dvp;
+                       if (attr != NULL) {
+                               attr->sa_mask = SMB_AT_ALL;
+                               (void) smb_vop_getattr(*vpp, NULL, attr, 0,
+                                   zone_kcred());
+                       }
                        return (0);
                }