smbd: Add "posix" flag to openat_pathref_dirfsp_nosymlink()

smbd: Add "posix" flag to openat_pathref_dirfsp_nosymlink()

Don't do the get_real_filename() retry if we're in posix context of if
the connection is case sensitive.

The whole concept of case sensivity blows my brain. In SMB1 without
posix extensions it's a per-request thing. In SMB2 without posix
extensions this should just depend on "case sensitive = yes/no", and
in future SMB2 posix extensions this will become a per-request thing
again, depending on the existence of the posix create context.

Then there are other semantics that are attached to posix-ness, which
have nothing to do with case sensivity. See for example merge request
2819 and bug 8776, or commit f0e1137425f. Also see
check_path_syntax_internal().

This patch uses the same flags as openat_pathref_fsp_case_insensitive()
does, but I am 100% certain this is wrong in a subtle way.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Thu Dec 15 11:30:04 UTC 2022 on sn-devel-184