NFS: Add nfs4_unique_id boot parameter (6f2ea7f2) · Commits · 戴 / test

Documentation/filesystems/nfs/nfs.txt

+41 −3

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		@@ -12,9 +12,47 @@ and work is in progress on adding support for minor version 1 of the NFSv4
		protocol.

		The purpose of this document is to provide information on some of the
		upcall interfaces that are used in order to provide the NFS client with
		some of the information that it requires in order to fully comply with
		the NFS spec.
		special features of the NFS client that can be configured by system
		administrators.


		The nfs4_unique_id parameter
		============================

		NFSv4 requires clients to identify themselves to servers with a unique
		string. File open and lock state shared between one client and one server
		is associated with this identity. To support robust NFSv4 state recovery
		and transparent state migration, this identity string must not change
		across client reboots.

		Without any other intervention, the Linux client uses a string that contains
		the local system's node name. System administrators, however, often do not
		take care to ensure that node names are fully qualified and do not change
		over the lifetime of a client system. Node names can have other
		administrative requirements that require particular behavior that does not
		work well as part of an nfs_client_id4 string.

		The nfs.nfs4_unique_id boot parameter specifies a unique string that can be
		used instead of a system's node name when an NFS client identifies itself to
		a server. Thus, if the system's node name is not unique, or it changes, its
		nfs.nfs4_unique_id stays the same, preventing collision with other clients
		or loss of state during NFS reboot recovery or transparent state migration.

		The nfs.nfs4_unique_id string is typically a UUID, though it can contain
		anything that is believed to be unique across all NFS clients. An
		nfs4_unique_id string should be chosen when a client system is installed,
		just as a system's root file system gets a fresh UUID in its label at
		install time.

		The string should remain fixed for the lifetime of the client. It can be
		changed safely if care is taken that the client shuts down cleanly and all
		outstanding NFSv4 state has expired, to prevent loss of NFSv4 state.

		This string can be stored in an NFS client's grub.conf, or it can be provided
		via a net boot facility such as PXE. It may also be specified as an nfs.ko
		module parameter. Specifying a uniquifier string is not support for NFS
		clients running in containers.


		The DNS resolver
		================

Documentation/kernel-parameters.txt

+5 −0

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		@@ -1719,6 +1719,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
		will be autodetected by the client, and it will fall
		back to using the idmapper.
		To turn off this behaviour, set the value to '0'.
		nfs.nfs4_unique_id=
		[NFS4] Specify an additional fixed unique ident-
		ification string that NFSv4 clients can insert into
		their nfs_client_id4 string. This is typically a
		UUID that is generated at system install time.

		nfs.send_implementation_id =
		[NFSv4.1] Send client implementation identification

fs/nfs/nfs4_fs.h

+3 −0

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		@@ -380,6 +380,9 @@ extern bool nfs4_disable_idmapping;
		extern unsigned short max_session_slots;
		extern unsigned short send_implementation_id;

		#define NFS4_CLIENT_ID_UNIQ_LEN (64)
		extern char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN];

		/* nfs4sysctl.c */
		#ifdef CONFIG_SYSCTL
		int nfs4_register_sysctl(void);

fs/nfs/nfs4proc.c

+5 −1

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		@@ -4068,9 +4068,13 @@ static unsigned int
		nfs4_init_uniform_client_string(const struct nfs_client *clp,
		char *buf, size_t len)
		{
		char *nodename = clp->cl_rpcclient->cl_nodename;

		if (nfs4_client_id_uniquifier[0] != '\0')
		nodename = nfs4_client_id_uniquifier;
		return scnprintf(buf, len, "Linux NFSv%u.%u %s",
		clp->rpc_ops->version, clp->cl_minorversion,
		clp->cl_rpcclient->cl_nodename);
		nodename);
		}

		/**

fs/nfs/super.c

+5 −0

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		@@ -2662,6 +2662,7 @@ unsigned int nfs_idmap_cache_timeout = 600;
		bool nfs4_disable_idmapping = true;
		unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
		unsigned short send_implementation_id = 1;
		char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";

		EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
		EXPORT_SYMBOL_GPL(nfs_callback_tcpport);
		@@ -2669,6 +2670,7 @@ EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
		EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
		EXPORT_SYMBOL_GPL(max_session_slots);
		EXPORT_SYMBOL_GPL(send_implementation_id);
		EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);

		#define NFS_CALLBACK_MAXPORTNR (65535U)

		@@ -2694,6 +2696,8 @@ static struct kernel_param_ops param_ops_portnr = {
		module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
		module_param(nfs_idmap_cache_timeout, int, 0644);
		module_param(nfs4_disable_idmapping, bool, 0644);
		module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
		NFS4_CLIENT_ID_UNIQ_LEN, 0600);
		MODULE_PARM_DESC(nfs4_disable_idmapping,
		"Turn off NFSv4 idmapping when using 'sec=sys'");
		module_param(max_session_slots, ushort, 0644);
		@@ -2702,6 +2706,7 @@ MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
		module_param(send_implementation_id, ushort, 0644);
		MODULE_PARM_DESC(send_implementation_id,
		"Send implementation ID with NFSv4.1 exchange_id");
		MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
		MODULE_ALIAS("nfs4");

		#endif /* CONFIG_NFS_V4 */

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