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man pages section 8: System Administration Commands

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Updated: Thursday, June 13, 2019

vfs_zfsacl (8)


vfs_zfsacl - ZFS ACL samba module


vfs objects = zfsacl


System Administration tools                                      VFS_ZFSACL(8)

       vfs_zfsacl - ZFS ACL samba module

       vfs objects = zfsacl

       This VFS module is part of the samba(7) suite.

       The zfsacl VFS module is the home for all ACL extensions that Samba
       requires for proper integration with ZFS.

       Currently the zfsacl vfs module provides extensions in following areas

              o   NFSv4 ACL Interfaces with configurable options for ZFS

       NOTE:This module follows the posix-acl behaviour and hence allows
       permission stealing via chown. Samba might allow at a later point in
       time, to restrict the chown via this module as such restrictions are
       the responsibility of the underlying filesystem than of Samba.

       This module makes use of the smb.conf parameter acl map full control =
       acl map full control When set to yes (the default), this parameter will
       add in the FILE_DELETE_CHILD bit on a returned ACE entry for a file
       (not a directory) that already contains all file permissions except for
       FILE_DELETE and FILE_DELETE_CHILD. This can prevent Windows
       applications that request GENERIC_ALL access from getting ACCESS_DENIED
       errors when running against a filesystem with NFSv4 compatible ACLs.

       This module is stackable.

       Since Samba 4.0 all options are per share options.

       nfs4:mode = [ simple | special ]
           Controls substitution of special IDs (OWNER@ and GROUP@) on ZFS.
           The use of mode simple is recommended. In this mode only non
           inheriting ACL entries for the file owner and group are mapped to
           special IDs.

           The following MODEs are understood by the module:

                  o   simple(default) - use OWNER@ and GROUP@ special IDs for
                      non inheriting ACEs only.

                  o   special(deprecated) - use OWNER@ and GROUP@ special IDs
                      in ACEs for all file owner and group ACEs.

       nfs4:acedup = [dontcare|reject|ignore|merge]
           This parameter configures how Samba handles duplicate ACEs
           encountered in ZFS ACLs. ZFS allows/creates duplicate ACE for
           different bits for same ID.

           Following is the behaviour of Samba for different values :

                  o   dontcare (default) - copy the ACEs as they come

                  o   reject - stop operation and exit with error on ACL set

                  o   ignore - don't include the second matching ACE

                  o   merge - bitwise OR the 2 ace.flag fields and 2 ace.mask
                      fields of the 2 duplicate ACEs into 1 ACE

       nfs4:chown = [yes|no]
           This parameter allows enabling or disabling the chown supported by
           the underlying filesystem. This parameter should be enabled with
           care as it might leave your system insecure.

           Some filesystems allow chown as a) giving b) stealing. It is the
           latter that is considered a risk.

           Following is the behaviour of Samba for different values :

                  o   yes - Enable chown if as supported by the under

                  o   no (default) - Disable chown

       A ZFS mount can be exported via Samba as follows :

                vfs objects = zfsacl
                path = /test/zfs_mount
                nfs4: mode = special
                nfs4: acedup = merge

       This man page is part of version 4.9.3 of the Samba suite.

       The original Samba software and related utilities were created by
       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | service/network/samba |
       |Stability      | Volatile              |
       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at http://www.samba.org/.

Samba 4.9.3                       01/24/2019                     VFS_ZFSACL(8)