diff options
Diffstat (limited to 'Documentation/filesystems/cifs/cifsroot.txt')
| -rw-r--r-- | Documentation/filesystems/cifs/cifsroot.txt | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/Documentation/filesystems/cifs/cifsroot.txt b/Documentation/filesystems/cifs/cifsroot.txt deleted file mode 100644 index 947b7ec6ce9e..000000000000 --- a/Documentation/filesystems/cifs/cifsroot.txt +++ /dev/null @@ -1,97 +0,0 @@ -Mounting root file system via SMB (cifs.ko) -=========================================== - -Written 2019 by Paulo Alcantara <palcantara@suse.de> -Written 2019 by Aurelien Aptel <aaptel@suse.com> - -The CONFIG_CIFS_ROOT option enables experimental root file system -support over the SMB protocol via cifs.ko. - -It introduces a new kernel command-line option called 'cifsroot=' -which will tell the kernel to mount the root file system over the -network by utilizing SMB or CIFS protocol. - -In order to mount, the network stack will also need to be set up by -using 'ip=' config option. For more details, see -Documentation/admin-guide/nfs/nfsroot.rst. - -A CIFS root mount currently requires the use of SMB1+UNIX Extensions -which is only supported by the Samba server. SMB1 is the older -deprecated version of the protocol but it has been extended to support -POSIX features (See [1]). The equivalent extensions for the newer -recommended version of the protocol (SMB3) have not been fully -implemented yet which means SMB3 doesn't support some required POSIX -file system objects (e.g. block devices, pipes, sockets). - -As a result, a CIFS root will default to SMB1 for now but the version -to use can nonetheless be changed via the 'vers=' mount option. This -default will change once the SMB3 POSIX extensions are fully -implemented. - -Server configuration -==================== - -To enable SMB1+UNIX extensions you will need to set these global -settings in Samba smb.conf: - - [global] - server min protocol = NT1 - unix extension = yes # default - -Kernel command line -=================== - -root=/dev/cifs - -This is just a virtual device that basically tells the kernel to mount -the root file system via SMB protocol. - -cifsroot=//<server-ip>/<share>[,options] - -Enables the kernel to mount the root file system via SMB that are -located in the <server-ip> and <share> specified in this option. - -The default mount options are set in fs/cifs/cifsroot.c. - -server-ip - IPv4 address of the server. - -share - Path to SMB share (rootfs). - -options - Optional mount options. For more information, see mount.cifs(8). - -Examples -======== - -Export root file system as a Samba share in smb.conf file. - -... -[linux] - path = /path/to/rootfs - read only = no - guest ok = yes - force user = root - force group = root - browseable = yes - writeable = yes - admin users = root - public = yes - create mask = 0777 - directory mask = 0777 -... - -Restart smb service. - -# systemctl restart smb - -Test it under QEMU on a kernel built with CONFIG_CIFS_ROOT and -CONFIG_IP_PNP options enabled. - -# qemu-system-x86_64 -enable-kvm -cpu host -m 1024 \ - -kernel /path/to/linux/arch/x86/boot/bzImage -nographic \ - -append "root=/dev/cifs rw ip=dhcp cifsroot=//10.0.2.2/linux,username=foo,password=bar console=ttyS0 3" - - -1: https://wiki.samba.org/index.php/UNIX_Extensions |