# SPDX-License-Identifier: GPL-2.0-only config NFS_FS tristate "NFS client support" depends on INET && FILE_LOCKING && MULTIUSER select LOCKD select SUNRPC select NFS_ACL_SUPPORT if NFS_V3_ACL help Choose Y here if you want to access files residing on other computers using Sun's Network File System protocol. To compile this file system support as a module, choose M here: the module will be called nfs. To mount file systems exported by NFS servers, you also need to install the user space mount.nfs command which can be found in the Linux nfs-utils package, available from http://linux-nfs.org/. Information about using the mount command is available in the mount(8) man page. More detail about the Linux NFS client implementation is available via the nfs(5) man page. Below you can choose which versions of the NFS protocol are available in the kernel to mount NFS servers. Support for NFS version 2 (RFC 1094) is always available when NFS_FS is selected. To configure a system which mounts its root file system via NFS at boot time, say Y here, select "Kernel level IP autoconfiguration" in the NETWORK menu, and select "Root file system on NFS" below. You cannot compile this file system as a module in this case. If unsure, say N. config NFS_V2 tristate "NFS client support for NFS version 2" depends on NFS_FS default y help This option enables support for version 2 of the NFS protocol (RFC 1094) in the kernel's NFS client. If unsure, say Y. config NFS_V3 tristate "NFS client support for NFS version 3" depends on NFS_FS default y help This option enables support for version 3 of the NFS protocol (RFC 1813) in the kernel's NFS client. If unsure, say Y. config NFS_V3_ACL bool "NFS client support for the NFSv3 ACL protocol extension" depends on NFS_V3 help Some NFS servers support an auxiliary NFSv3 ACL protocol that Sun added to Solaris but never became an official part of the NFS version 3 protocol. This protocol extension allows applications on NFS clients to manipulate POSIX Access Control Lists on files residing on NFS servers. NFS servers enforce ACLs on local files whether this protocol is available or not. Choose Y here if your NFS server supports the Solaris NFSv3 ACL protocol extension and you want your NFS client to allow applications to access and modify ACLs on files on the server. Most NFS servers don't support the Solaris NFSv3 ACL protocol extension. You can choose N here or specify the "noacl" mount option to prevent your NFS client from trying to use the NFSv3 ACL protocol. If unsure, say N. config NFS_V4 tristate "NFS client support for NFS version 4" depends on NFS_FS select SUNRPC_GSS select KEYS help This option enables support for version 4 of the NFS protocol (RFC 3530) in the kernel's NFS client. To mount NFS servers using NFSv4, you also need to install user space programs which can be found in the Linux nfs-utils package, available from http://linux-nfs.org/. If unsure, say Y. config NFS_SWAP bool "Provide swap over NFS support" default n depends on NFS_FS && SWAP select SUNRPC_SWAP help This option enables swapon to work on files located on NFS mounts. config NFS_V4_1 bool "NFS client support for NFSv4.1" depends on NFS_V4 select SUNRPC_BACKCHANNEL help This option enables support for minor version 1 of the NFSv4 protocol (RFC 5661) in the kernel's NFS client. If unsure, say N. config NFS_V4_2 bool "NFS client support for NFSv4.2" depends on NFS_V4_1 help This option enables support for minor version 2 of the NFSv4 protocol in the kernel's NFS client. If unsure, say N. config PNFS_FILE_LAYOUT tristate depends on NFS_V4_1 default NFS_V4 config PNFS_BLOCK tristate depends on NFS_V4_1 && BLK_DEV_DM default NFS_V4 config PNFS_FLEXFILE_LAYOUT tristate depends on NFS_V4_1 && NFS_V3 default NFS_V4 config NFS_V4_1_IMPLEMENTATION_ID_DOMAIN string "NFSv4.1 Implementation ID Domain" depends on NFS_V4_1 default "kernel.org" help This option defines the domain portion of the implementation ID that may be sent in the NFS exchange_id operation. The value must be in the format of a DNS domain name and should be set to the DNS domain name of the distribution. If the NFS client is unchanged from the upstream kernel, this option should be set to the default "kernel.org". config NFS_V4_1_MIGRATION bool "NFSv4.1 client support for migration" depends on NFS_V4_1 default n help This option makes the NFS client advertise to NFSv4.1 servers that it can support NFSv4 migration. The NFSv4.1 pieces of the Linux NFSv4 migration implementation are still experimental. If you are not an NFSv4 developer, say N here. config NFS_V4_SECURITY_LABEL bool depends on NFS_V4_2 && SECURITY default y config ROOT_NFS bool "Root file system on NFS" depends on NFS_FS=y && IP_PNP help If you want your system to mount its root file system via NFS, choose Y here. This is common practice for managing systems without local permanent storage. For details, read . Most people say N here. config NFS_FSCACHE bool "Provide NFS client caching support" depends on NFS_FS=m && FSCACHE || NFS_FS=y && FSCACHE=y help Say Y here if you want NFS data to be cached locally on disc through the general filesystem cache manager config NFS_USE_LEGACY_DNS bool "Use the legacy NFS DNS resolver" depends on NFS_V4 help The kernel now provides a method for translating a host name into an IP address. Select Y here if you would rather use your own DNS resolver script. If unsure, say N config NFS_USE_KERNEL_DNS bool depends on NFS_V4 && !NFS_USE_LEGACY_DNS select DNS_RESOLVER default y config NFS_DEBUG bool depends on NFS_FS && SUNRPC_DEBUG select CRC32 default y config NFS_DISABLE_UDP_SUPPORT bool "NFS: Disable NFS UDP protocol support" depends on NFS_FS default n help Choose Y here to disable the use of NFS over UDP. NFS over UDP on modern networks (1Gb+) can lead to data corruption caused by fragmentation during high loads. config NFS_V4_2_READ_PLUS bool "NFS: Enable support for the NFSv4.2 READ_PLUS operation" depends on NFS_V4_2 default n help This is intended for developers only. The READ_PLUS operation has been shown to have issues under specific conditions and should not be used in production.