samba - Jan 2025 - Can a macOS (Posix) client see symlinks on FreeBSD server as symlinks on client?

Op 06-01-2025 om 10:39 schreef Rowland Penny via samba:
> On Sun, 5 Jan 2025 22:43:23 -0800
> Jim DeLaHunt via samba <samba at lists.samba.org> wrote:
>
>> Hello, Samba folks:
>>
>> Is there a setting I could invoke, either on my server's Samba
>> configuration or on my macOS smbfs configuration, which would make
>> the hundreds of legacy symbolic links on the server's Posix file
>> system appear as symbolic links on the macOS client?
>>
>> Does Samba claim that it will present symlinks on the server file
>> system as symlinks to a client?
>>
>>
>> Some background:
>>
>> I have a macOS client which uses files from a small FreeBSD-based
>> file server. I just switched from afp to smb as the way of connecting
>> to my shares. With afp, my macOS client could create a Posix-style
>> symbolic link on the server, and it would be stored as a Posix-style
>> symbolic link on the server's file system. My macOS client saw
>> symbolic links on the server's file system as symbolic links on the
>> shared volume. These links are all internal to the directory trees of
>> the share: think `../sibling/child/foo.txt` relative links.
>>
>> Now, using smb, I don't have that behaviour. It appears that most
of
>> the symlinks on the server file system, which I created via an afp
>> connection, now appear in my macOS clients as directories rather than
>> symlinks.
>>
>> Below is a local symlink, created on my client a year ago, then
>> copied to the server via rsync over afp, and which is a symlink on
>> the server's file system:
>>
>> % ls -ld ~/Documents/Projects/2024/@@\ 2023
>> /Volumes/MyShare/Projects/2024/@@\ 2023
>> lrwxr-xr-x 1 jdlh staff???? 7 Dec 30? 2023
>> '/Users/myuser/Projects/2024/@@ 2023' -> ../2023
>> drwx------ 1 jdlh staff 16384 Dec 30? 2023
>> '/Volumes/MyShare/Projects/2024/@@ 2023'
>>
>> The macOS client view via smb of the FreeBSD symlink is some kind of
>> simulated directory (see the "d" in the first column), while
it sees
>> the symlink on the local filesystem as a symlink (see the "l"
in the
>> first column, and the arrow pointing to the link path).
>>
>> Symbolic links which is create via the smb connection to this server
>> do appear as symbolic links. On the server file system, they appear
>> to be Minshall+French symlinks. They are 1067-byte text files with
>> that format.
>>
>> I have tried reading through the documentation to understand this,
>> but I'm having a hard time finding documentation of these details
for
>> Samba, and the server configuration, and the client configuration.
>>
>> The server is a TrueNAS version 13 NAS appliance, with FreeBSD OS and
>> a ZFS filesystem. It appears to be running smbd Version 4.15.13. The
>> global part of the smb4.conf file includes, "unix extensions =?
yes".
>> I don't see entries for the individual shares, but they must be
>> somewhere.? I have checked a box in the admin UI which I think
>> invokes "vfs_fruit", but I don't know how to be sure.
"sudo
>> smbstatus" doesn't seem to say.
>>
>> The client runs a macOS Sonoma 14.7.2 OS, and Apples "smbfs"
variant
>> of Samba. `smbutil statshares -m /Volumes/MyShare` prints various
>> attributes including, "SMB_VERSION SMB_3.1.1". My
understanding is
>> that this is plenty modern enough to support Posix well.
>>
>> As I read the Samba website, especially the wiki, I don't find a
page
>> that says, "This is the behaviour which Samba provides with
regards
>> to symlinks."?? There are pages like
>> <https://wiki.samba.org/index.php/SMB3-Linux>, which reads to me
like
>> an implementation design.? There are pages like
>> <https://wiki.samba.org/index.php/UNIX_Extensions> which appear
to be
>> historical, but still show up in search results. Is there somewhere
>> some documentation which tells me what the software actually does,
>> rather than what it plans to do or used to do?
>>
>> So: is there a way for me to get Samba server to present Posix
>> symlinks to Posix clients as symlinks?
>>
>> Thank you in advance for your help!
>>   ???? ?Jim DeLaHunt
>>
> The problem with symlinks on Samba is that they require 'unix
> extensions = yes', which requires SMBv1 (This parameter has been
renamed
> 'smb1 unix extensions' in the latest versions of Samba) and by
default
> it is set to 'no'.
>
> There is ongoing work for the SMBv3 version of 'unix extensions',
but
> at present (as far as I am aware) there is no support for symlinks and,
> from the comments made by one of the Samba devs, it is unlikely to ever
> support symlinks, though reparse points are likely.
Correct, one addition: on the client side (for linux clients) a reparse 
point is presented as a symlink.
As far as I know that is already available in the linux kernel client, 
however on the server-side Samba is not ready yet.

In the case presented above, there is another unknown, namely how is the 
implementation in the macOS client regarding symlinks and reparse points?

- Kees.
>
> Rowland
>

On 2025-01-06 01:49, Kees van Vloten via samba wrote:
>
> Op 06-01-2025 om 10:39 schreef Rowland Penny via samba:
>> On Sun, 5 Jan 2025 22:43:23 -0800
>> Jim DeLaHunt via samba <samba at lists.samba.org> wrote:
>>
>>> Hello, Samba folks:
>>>
>>> Is there a setting I could invoke, either on my server's Samba
>>> configuration or on my macOS smbfs configuration, which would make
>>> the hundreds of legacy symbolic links on the server's Posix
file
>>> system appear as symbolic links on the macOS client?
>>> ...[elided]...
>>>
>> ...[elided]...
>
> ...[elided]...
> In the case presented above, there is another unknown, namely how is 
> the implementation in the macOS client regarding symlinks and reparse 
> points?
Kees, thank you for the reply.

How does the macOS client behave?? That is a great question. I have not 
found good documentation on the subject. Apple has posted some Samba 
code publicly at
<https://github.com/apple-oss-distributions/smb/blob/main/kernel/smbfs/smbfs_smb.c>
and the rest of that repository.? I have not tried to read through it to 
figure out exactly how it behaves. And, I don't know for sure that the 
source code there was what was compiled to make the executables on my 
macOS machine.

Best regards,
 ??? ?Jim DeLaHunt