^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) .. SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) ===========================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) Mounting root file system via SMB (cifs.ko)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) ===========================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) Written 2019 by Paulo Alcantara <palcantara@suse.de>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) Written 2019 by Aurelien Aptel <aaptel@suse.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) The CONFIG_CIFS_ROOT option enables experimental root file system
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) support over the SMB protocol via cifs.ko.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) It introduces a new kernel command-line option called 'cifsroot='
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) which will tell the kernel to mount the root file system over the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) network by utilizing SMB or CIFS protocol.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) In order to mount, the network stack will also need to be set up by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) using 'ip=' config option. For more details, see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) Documentation/admin-guide/nfs/nfsroot.rst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) A CIFS root mount currently requires the use of SMB1+UNIX Extensions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) which is only supported by the Samba server. SMB1 is the older
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) deprecated version of the protocol but it has been extended to support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) POSIX features (See [1]). The equivalent extensions for the newer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) recommended version of the protocol (SMB3) have not been fully
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) implemented yet which means SMB3 doesn't support some required POSIX
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) file system objects (e.g. block devices, pipes, sockets).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) As a result, a CIFS root will default to SMB1 for now but the version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) to use can nonetheless be changed via the 'vers=' mount option. This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) default will change once the SMB3 POSIX extensions are fully
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) implemented.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) Server configuration
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) ====================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) To enable SMB1+UNIX extensions you will need to set these global
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) settings in Samba smb.conf::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) [global]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) server min protocol = NT1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) unix extension = yes # default
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) Kernel command line
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) ===================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) ::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) root=/dev/cifs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) This is just a virtual device that basically tells the kernel to mount
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) the root file system via SMB protocol.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) ::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) cifsroot=//<server-ip>/<share>[,options]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) Enables the kernel to mount the root file system via SMB that are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) located in the <server-ip> and <share> specified in this option.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) The default mount options are set in fs/cifs/cifsroot.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) server-ip
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) IPv4 address of the server.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) share
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) Path to SMB share (rootfs).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) options
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) Optional mount options. For more information, see mount.cifs(8).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) Examples
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) ========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) Export root file system as a Samba share in smb.conf file::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) ...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) [linux]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) path = /path/to/rootfs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) read only = no
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) guest ok = yes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) force user = root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) force group = root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) browseable = yes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) writeable = yes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) admin users = root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) public = yes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) create mask = 0777
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) directory mask = 0777
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) ...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) Restart smb service::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) # systemctl restart smb
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) Test it under QEMU on a kernel built with CONFIG_CIFS_ROOT and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) CONFIG_IP_PNP options enabled::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) # qemu-system-x86_64 -enable-kvm -cpu host -m 1024 \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) -kernel /path/to/linux/arch/x86/boot/bzImage -nographic \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) -append "root=/dev/cifs rw ip=dhcp cifsroot=//10.0.2.2/linux,username=foo,password=bar console=ttyS0 3"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 1: https://wiki.samba.org/index.php/UNIX_Extensions
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags