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

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.

Rowland

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 01:39, Rowland Penny via samba wrote:
> 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?
>>
>> ...[elided]...
> ...[elided]... 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.
Thank you for the reply, Rowland. This matches a reply at SuperUser 
Stack Exchange, <https://superuser.com/a/1824854/114802>. It said, 
'[OP's] mount most likely uses SMBv3, which has "POSIX
extensions" as
the equivalent, but as far as I know, those are not yet 100% implemented 
in Linux and Samba.'

It would be helpful to be able to trace the statement of "Samba server 
4.x using protocol SMB 3.1.1 will not create symlinks on server file 
system, and will write Minshall+French symlinks only" to release notes 
or a roadmap or some other kind of documentation. I don't know Samba's 
documentation practices very well. Does that sort of thing get written 
down in an authoritative location?

Best regards,

 ??????? ?Jim DeLaHunt