From cbf1107126af2950623fafdaa5c9df43ab00f046 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 9 Aug 2009 15:06:19 -0400 Subject: SUNRPC: convert some sysctls into module parameters Parameters like the minimum reserved port, and the number of slot entries should really be module parameters rather than sysctls. Signed-off-by: Trond Myklebust --- Documentation/kernel-parameters.txt | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index dd1a6d4bb747..2f1820683b69 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2391,6 +2391,18 @@ and is between 256 and 4096 characters. It is defined in the file stifb= [HW] Format: bpp:[:[:...]] + sunrpc.min_resvport= + sunrpc.max_resvport= + [NFS,SUNRPC] + SunRPC servers often require that client requests + originate from a privileged port (i.e. a port in the + range 0 < portnr < 1024). + An administrator who wishes to reserve some of these + ports for other uses may adjust the range that the + kernel's sunrpc client considers to be privileged + using these two parameters to set the minimum and + maximum port values. + sunrpc.pool_mode= [NFS] Control how the NFS server code allocates CPUs to @@ -2407,6 +2419,15 @@ and is between 256 and 4096 characters. It is defined in the file pernode one pool for each NUMA node (equivalent to global on non-NUMA machines) + sunrpc.tcp_slot_table_entries= + sunrpc.udp_slot_table_entries= + [NFS,SUNRPC] + Sets the upper limit on the number of simultaneous + RPC calls that can be sent from the client to a + server. Increasing these values may allow you to + improve throughput, but will also increase the + amount of memory reserved for use by the client. + swiotlb= [IA-64] Number of I/O TLB slabs switches= [HW,M68k] -- cgit v1.2.2 From e571cbf1a4f8d8b6cfd4898df718dae84c75a8e1 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 19 Aug 2009 18:12:27 -0400 Subject: NFS: Add a dns resolver for use with NFSv4 referrals and migration The NFSv4 and NFSv4.1 protocols both allow for the redirection of a client from one server to another in order to support filesystem migration and replication. For full protocol support, we need to add the ability to convert a DNS host name into an IP address that we can feed to the RPC client. We'll reuse the sunrpc cache, now that it has been converted to work with rpc_pipefs. Signed-off-by: Trond Myklebust --- Documentation/filesystems/nfs.txt | 98 +++++++++++++++++++++++++++++++++++++ Documentation/kernel-parameters.txt | 8 +++ 2 files changed, 106 insertions(+) create mode 100644 Documentation/filesystems/nfs.txt (limited to 'Documentation') diff --git a/Documentation/filesystems/nfs.txt b/Documentation/filesystems/nfs.txt new file mode 100644 index 000000000000..f50f26ce6cd0 --- /dev/null +++ b/Documentation/filesystems/nfs.txt @@ -0,0 +1,98 @@ + +The NFS client +============== + +The NFS version 2 protocol was first documented in RFC1094 (March 1989). +Since then two more major releases of NFS have been published, with NFSv3 +being documented in RFC1813 (June 1995), and NFSv4 in RFC3530 (April +2003). + +The Linux NFS client currently supports all the above published versions, +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. + +The DNS resolver +================ + +NFSv4 allows for one server to refer the NFS client to data that has been +migrated onto another server by means of the special "fs_locations" +attribute. See + http://tools.ietf.org/html/rfc3530#section-6 +and + http://tools.ietf.org/html/draft-ietf-nfsv4-referrals-00 + +The fs_locations information can take the form of either an ip address and +a path, or a DNS hostname and a path. The latter requires the NFS client to +do a DNS lookup in order to mount the new volume, and hence the need for an +upcall to allow userland to provide this service. + +Assuming that the user has the 'rpc_pipefs' filesystem mounted in the usual +/var/lib/nfs/rpc_pipefs, the upcall consists of the following steps: + + (1) The process checks the dns_resolve cache to see if it contains a + valid entry. If so, it returns that entry and exits. + + (2) If no valid entry exists, the helper script '/sbin/nfs_cache_getent' + (may be changed using the 'nfs.cache_getent' kernel boot parameter) + is run, with two arguments: + - the cache name, "dns_resolve" + - the hostname to resolve + + (3) After looking up the corresponding ip address, the helper script + writes the result into the rpc_pipefs pseudo-file + '/var/lib/nfs/rpc_pipefs/cache/dns_resolve/channel' + in the following (text) format: + + " \n" + + Where is in the usual IPv4 (123.456.78.90) or IPv6 + (ffee:ddcc:bbaa:9988:7766:5544:3322:1100, ffee::1100, ...) format. + is identical to the second argument of the helper + script, and is the 'time to live' of this cache entry (in + units of seconds). + + Note: If is invalid, say the string "0", then a negative + entry is created, which will cause the kernel to treat the hostname + as having no valid DNS translation. + + + + +A basic sample /sbin/nfs_cache_getent +===================================== + +#!/bin/bash +# +ttl=600 +# +cut=/usr/bin/cut +getent=/usr/bin/getent +rpc_pipefs=/var/lib/nfs/rpc_pipefs +# +die() +{ + echo "Usage: $0 cache_name entry_name" + exit 1 +} + +[ $# -lt 2 ] && die +cachename="$1" +cache_path=${rpc_pipefs}/cache/${cachename}/channel + +case "${cachename}" in + dns_resolve) + name="$2" + result="$(${getent} hosts ${name} | ${cut} -f1 -d\ )" + [ -z "${result}" ] && result="0" + ;; + *) + die + ;; +esac +echo "${result} ${name} ${ttl}" >${cache_path} + diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c08813dbfce2..ce8853755814 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1503,6 +1503,14 @@ and is between 256 and 4096 characters. It is defined in the file [NFS] set the TCP port on which the NFSv4 callback channel should listen. + nfs.cache_getent= + [NFS] sets the pathname to the program which is used + to update the NFS client cache entries. + + nfs.cache_getent_timeout= + [NFS] sets the timeout after which an attempt to + update a cache entry is deemed to have failed. + nfs.idmap_cache_timeout= [NFS] set the maximum lifetime for idmapper cache entries. -- cgit v1.2.2