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-rw-r--r--Documentation/filesystems/nfs.txt98
-rw-r--r--Documentation/kernel-parameters.txt29
-rw-r--r--fs/lockd/host.c14
-rw-r--r--fs/lockd/mon.c44
-rw-r--r--fs/nfs/Makefile3
-rw-r--r--fs/nfs/cache_lib.c140
-rw-r--r--fs/nfs/cache_lib.h27
-rw-r--r--fs/nfs/callback.c26
-rw-r--r--fs/nfs/client.c15
-rw-r--r--fs/nfs/direct.c3
-rw-r--r--fs/nfs/dns_resolve.c335
-rw-r--r--fs/nfs/dns_resolve.h14
-rw-r--r--fs/nfs/file.c49
-rw-r--r--fs/nfs/idmap.c6
-rw-r--r--fs/nfs/inode.c100
-rw-r--r--fs/nfs/internal.h39
-rw-r--r--fs/nfs/mount_clnt.c83
-rw-r--r--fs/nfs/nfs3proc.c1
-rw-r--r--fs/nfs/nfs4namespace.c24
-rw-r--r--fs/nfs/nfs4proc.c40
-rw-r--r--fs/nfs/nfs4xdr.c1460
-rw-r--r--fs/nfs/super.c451
-rw-r--r--fs/nfs/write.c91
-rw-r--r--fs/nfsd/export.c14
-rw-r--r--fs/nfsd/nfs4idmap.c20
-rw-r--r--fs/nfsd/nfsctl.c21
-rw-r--r--include/linux/nfs4.h1
-rw-r--r--include/linux/nfs_fs_sb.h9
-rw-r--r--include/linux/sunrpc/cache.h40
-rw-r--r--include/linux/sunrpc/clnt.h43
-rw-r--r--include/linux/sunrpc/msg_prot.h17
-rw-r--r--include/linux/sunrpc/rpc_pipe_fs.h20
-rw-r--r--include/linux/sunrpc/xdr.h10
-rw-r--r--include/linux/sunrpc/xprt.h2
-rw-r--r--net/sunrpc/Makefile2
-rw-r--r--net/sunrpc/addr.c364
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c12
-rw-r--r--net/sunrpc/auth_gss/svcauth_gss.c7
-rw-r--r--net/sunrpc/cache.c622
-rw-r--r--net/sunrpc/clnt.c60
-rw-r--r--net/sunrpc/rpc_pipe.c685
-rw-r--r--net/sunrpc/rpcb_clnt.c420
-rw-r--r--net/sunrpc/sunrpc_syms.c2
-rw-r--r--net/sunrpc/svcauth_unix.c14
-rw-r--r--net/sunrpc/timer.c45
-rw-r--r--net/sunrpc/xdr.c12
-rw-r--r--net/sunrpc/xprtrdma/transport.c48
-rw-r--r--net/sunrpc/xprtsock.c287
48 files changed, 4064 insertions, 1805 deletions
diff --git a/Documentation/filesystems/nfs.txt b/Documentation/filesystems/nfs.txt
new file mode 100644
index 00000000000..f50f26ce6cd
--- /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:
+
+ "<ip address> <hostname> <ttl>\n"
+
+ Where <ip address> is in the usual IPv4 (123.456.78.90) or IPv6
+ (ffee:ddcc:bbaa:9988:7766:5544:3322:1100, ffee::1100, ...) format.
+ <hostname> is identical to the second argument of the helper
+ script, and <ttl> is the 'time to live' of this cache entry (in
+ units of seconds).
+
+ Note: If <ip address> 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 7936b801fe6..ce885375581 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.
@@ -2395,6 +2403,18 @@ and is between 256 and 4096 characters. It is defined in the file
stifb= [HW]
Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
+ 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
@@ -2411,6 +2431,15 @@ 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]
diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 99d737bd432..7cb076ac6b4 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -87,18 +87,6 @@ static unsigned int nlm_hash_address(const struct sockaddr *sap)
return hash & (NLM_HOST_NRHASH - 1);
}
-static void nlm_clear_port(struct sockaddr *sap)
-{
- switch (sap->sa_family) {
- case AF_INET:
- ((struct sockaddr_in *)sap)->sin_port = 0;
- break;
- case AF_INET6:
- ((struct sockaddr_in6 *)sap)->sin6_port = 0;
- break;
- }
-}
-
/*
* Common host lookup routine for server & client
*/
@@ -177,7 +165,7 @@ static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
host->h_addrbuf = nsm->sm_addrbuf;
memcpy(nlm_addr(host), ni->sap, ni->salen);
host->h_addrlen = ni->salen;
- nlm_clear_port(nlm_addr(host));
+ rpc_set_port(nlm_addr(host), 0);
memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
host->h_version = ni->version;
host->h_proto = ni->protocol;
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 7fce1b52584..30c933188dd 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -61,43 +61,6 @@ static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
return (struct sockaddr *)&nsm->sm_addr;
}
-static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf,
- const size_t len)
-{
- const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
- snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
-}
-
-static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf,
- const size_t len)
-{
- const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
-
- if (ipv6_addr_v4mapped(&sin6->sin6_addr))
- snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
- else if (sin6->sin6_scope_id != 0)
- snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
- sin6->sin6_scope_id);
- else
- snprintf(buf, len, "%pI6", &sin6->sin6_addr);
-}
-
-static void nsm_display_address(const struct sockaddr *sap,
- char *buf, const size_t len)
-{
- switch (sap->sa_family) {
- case AF_INET:
- nsm_display_ipv4_address(sap, buf, len);
- break;
- case AF_INET6:
- nsm_display_ipv6_address(sap, buf, len);
- break;
- default:
- snprintf(buf, len, "unsupported address family");
- break;
- }
-}
-
static struct rpc_clnt *nsm_create(void)
{
struct sockaddr_in sin = {
@@ -307,8 +270,11 @@ static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
memcpy(nsm_addr(new), sap, salen);
new->sm_addrlen = salen;
nsm_init_private(new);
- nsm_display_address((const struct sockaddr *)&new->sm_addr,
- new->sm_addrbuf, sizeof(new->sm_addrbuf));
+
+ if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
+ sizeof(new->sm_addrbuf)) == 0)
+ (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
+ "unsupported address family");
memcpy(new->sm_name, hostname, hostname_len);
new->sm_name[hostname_len] = '\0';
diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index 845159814de..da7fda639ea 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -6,7 +6,8 @@ obj-$(CONFIG_NFS_FS) += nfs.o
nfs-y := client.o dir.o file.o getroot.o inode.o super.o nfs2xdr.o \
direct.o pagelist.o proc.o read.o symlink.o unlink.o \
- write.o namespace.o mount_clnt.o
+ write.o namespace.o mount_clnt.o \
+ dns_resolve.o cache_lib.o
nfs-$(CONFIG_ROOT_NFS) += nfsroot.o
nfs-$(CONFIG_NFS_V3) += nfs3proc.o nfs3xdr.o
nfs-$(CONFIG_NFS_V3_ACL) += nfs3acl.o
diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
new file mode 100644
index 00000000000..b4ffd0146ea
--- /dev/null
+++ b/fs/nfs/cache_lib.c
@@ -0,0 +1,140 @@
+/*
+ * linux/fs/nfs/cache_lib.c
+ *
+ * Helper routines for the NFS client caches
+ *
+ * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
+ */
+#include <linux/kmod.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/sunrpc/cache.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+
+#include "cache_lib.h"
+
+#define NFS_CACHE_UPCALL_PATHLEN 256
+#define NFS_CACHE_UPCALL_TIMEOUT 15
+
+static char nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] =
+ "/sbin/nfs_cache_getent";
+static unsigned long nfs_cache_getent_timeout = NFS_CACHE_UPCALL_TIMEOUT;
+
+module_param_string(cache_getent, nfs_cache_getent_prog,
+ sizeof(nfs_cache_getent_prog), 0600);
+MODULE_PARM_DESC(cache_getent, "Path to the client cache upcall program");
+module_param_named(cache_getent_timeout, nfs_cache_getent_timeout, ulong, 0600);
+MODULE_PARM_DESC(cache_getent_timeout, "Timeout (in seconds) after which "
+ "the cache upcall is assumed to have failed");
+
+int nfs_cache_upcall(struct cache_detail *cd, char *entry_name)
+{
+ static char *envp[] = { "HOME=/",
+ "TERM=linux",
+ "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+ NULL
+ };
+ char *argv[] = {
+ nfs_cache_getent_prog,
+ cd->name,
+ entry_name,
+ NULL
+ };
+ int ret = -EACCES;
+
+ if (nfs_cache_getent_prog[0] == '\0')
+ goto out;
+ ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ /*
+ * Disable the upcall mechanism if we're getting an ENOENT or
+ * EACCES error. The admin can re-enable it on the fly by using
+ * sysfs to set the 'cache_getent' parameter once the problem
+ * has been fixed.
+ */
+ if (ret == -ENOENT || ret == -EACCES)
+ nfs_cache_getent_prog[0] = '\0';
+out:
+ return ret > 0 ? 0 : ret;
+}
+
+/*
+ * Deferred request handling
+ */
+void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq)
+{
+ if (atomic_dec_and_test(&dreq->count))
+ kfree(dreq);
+}
+
+static void nfs_dns_cache_revisit(struct cache_deferred_req *d, int toomany)
+{
+ struct nfs_cache_defer_req *dreq;
+
+ dreq = container_of(d, struct nfs_cache_defer_req, deferred_req);
+
+ complete_all(&dreq->completion);
+ nfs_cache_defer_req_put(dreq);
+}
+
+static struct cache_deferred_req *nfs_dns_cache_defer(struct cache_req *req)
+{
+ struct nfs_cache_defer_req *dreq;
+
+ dreq = container_of(req, struct nfs_cache_defer_req, req);
+ dreq->deferred_req.revisit = nfs_dns_cache_revisit;
+ atomic_inc(&dreq->count);
+
+ return &dreq->deferred_req;
+}
+
+struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void)
+{
+ struct nfs_cache_defer_req *dreq;
+
+ dreq = kzalloc(sizeof(*dreq), GFP_KERNEL);
+ if (dreq) {
+ init_completion(&dreq->completion);
+ atomic_set(&dreq->count, 1);
+ dreq->req.defer = nfs_dns_cache_defer;
+ }
+ return dreq;
+}
+
+int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
+{
+ if (wait_for_completion_timeout(&dreq->completion,
+ nfs_cache_getent_timeout * HZ) == 0)
+ return -ETIMEDOUT;
+ return 0;
+}
+
+int nfs_cache_register(struct cache_detail *cd)
+{
+ struct nameidata nd;
+ struct vfsmount *mnt;
+ int ret;
+
+ mnt = rpc_get_mount();
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+ ret = vfs_path_lookup(mnt->mnt_root, mnt, "/cache", 0, &nd);
+ if (ret)
+ goto err;
+ ret = sunrpc_cache_register_pipefs(nd.path.dentry,
+ cd->name, 0600, cd);
+ path_put(&nd.path);
+ if (!ret)
+ return ret;
+err:
+ rpc_put_mount();
+ return ret;
+}
+
+void nfs_cache_unregister(struct cache_detail *cd)
+{
+ sunrpc_cache_unregister_pipefs(cd);
+ rpc_put_mount();
+}
+
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
new file mode 100644
index 00000000000..76f856e284e
--- /dev/null
+++ b/fs/nfs/cache_lib.h
@@ -0,0 +1,27 @@
+/*
+ * Helper routines for the NFS client caches
+ *
+ * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/sunrpc/cache.h>
+#include <asm/atomic.h>
+
+/*
+ * Deferred request handling
+ */
+struct nfs_cache_defer_req {
+ struct cache_req req;
+ struct cache_deferred_req deferred_req;
+ struct completion completion;
+ atomic_t count;
+};
+
+extern int nfs_cache_upcall(struct cache_detail *cd, char *entry_name);
+extern struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void);
+extern void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq);
+extern int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq);
+
+extern int nfs_cache_register(struct cache_detail *cd);
+extern void nfs_cache_unregister(struct cache_detail *cd);
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 7f604c7941f..293fa0528a6 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -43,21 +43,29 @@ static struct svc_program nfs4_callback_program;
unsigned int nfs_callback_set_tcpport;
unsigned short nfs_callback_tcpport;
unsigned short nfs_callback_tcpport6;
-static const int nfs_set_port_min = 0;
-static const int nfs_set_port_max = 65535;
+#define NFS_CALLBACK_MAXPORTNR (65535U)
-static int param_set_port(const char *val, struct kernel_param *kp)
+static int param_set_portnr(const char *val, struct kernel_param *kp)
{
- char *endp;
- int num = simple_strtol(val, &endp, 0);
- if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
+ unsigned long num;
+ int ret;
+
+ if (!val)
+ return -EINVAL;
+ ret = strict_strtoul(val, 0, &num);
+ if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
return -EINVAL;
- *((int *)kp->arg) = num;
+ *((unsigned int *)kp->arg) = num;
return 0;
}
-module_param_call(callback_tcpport, param_set_port, param_get_int,
- &nfs_callback_set_tcpport, 0644);
+static int param_get_portnr(char *buffer, struct kernel_param *kp)
+{
+ return param_get_uint(buffer, kp);
+}
+#define param_check_portnr(name, p) __param_check(name, p, unsigned int);
+
+module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
/*
* This is the NFSv4 callback kernel thread.
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index c6be84a161f..e350bd6a233 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -809,6 +809,9 @@ static int nfs_init_server(struct nfs_server *server,
/* Initialise the client representation from the mount data */
server->flags = data->flags;
server->options = data->options;
+ server->caps |= NFS_CAP_HARDLINKS|NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
+ NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|NFS_CAP_OWNER_GROUP|
+ NFS_CAP_ATIME|NFS_CAP_CTIME|NFS_CAP_MTIME;
if (data->rsize)
server->rsize = nfs_block_size(data->rsize, NULL);
@@ -1075,10 +1078,6 @@ struct nfs_server *nfs_create_server(const struct nfs_parsed_mount_data *data,
(unsigned long long) server->fsid.major,
(unsigned long long) server->fsid.minor);
- BUG_ON(!server->nfs_client);
- BUG_ON(!server->nfs_client->rpc_ops);
- BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
-
spin_lock(&nfs_client_lock);
list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
@@ -1275,7 +1274,7 @@ static int nfs4_init_server(struct nfs_server *server,
/* Initialise the client representation from the mount data */
server->flags = data->flags;
- server->caps |= NFS_CAP_ATOMIC_OPEN;
+ server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR;
server->options = data->options;
/* Get a client record */
@@ -1360,10 +1359,6 @@ struct nfs_server *nfs4_create_server(const struct nfs_parsed_mount_data *data,
if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
server->namelen = NFS4_MAXNAMLEN;
- BUG_ON(!server->nfs_client);
- BUG_ON(!server->nfs_client->rpc_ops);
- BUG_ON(!server->nfs_client->rpc_ops->file_inode_ops);
-
spin_lock(&nfs_client_lock);
list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
@@ -1401,7 +1396,7 @@ struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
/* Initialise the client representation from the parent server */
nfs_server_copy_userdata(server, parent_server);
- server->caps |= NFS_CAP_ATOMIC_OPEN;
+ server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR;
/* Get a client representation.
* Note: NFSv4 always uses TCP, */
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index e4e089a8f29..6c3210099d5 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -934,9 +934,6 @@ out:
* back into its cache. We let the server do generic write
* parameter checking and report problems.
*
- * We also avoid an unnecessary invocation of generic_osync_inode(),
- * as it is fairly meaningless to sync the metadata of an NFS file.
- *
* We eliminate local atime updates, see direct read above.
*
* We avoid unnecessary page cache invalidations for normal cached
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
new file mode 100644
index 00000000000..f4d54ba97cc
--- /dev/null
+++ b/fs/nfs/dns_resolve.c
@@ -0,0 +1,335 @@
+/*
+ * linux/fs/nfs/dns_resolve.c
+ *
+ * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
+ *
+ * Resolves DNS hostnames into valid ip addresses
+ */
+
+#include <linux/hash.h>
+#include <linux/string.h>
+#include <linux/kmod.h>
+#include <linux/module.h>
+#include <linux/socket.h>
+#include <linux/seq_file.h>
+#include <linux/inet.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/cache.h>
+#include <linux/sunrpc/svcauth.h>
+
+#include "dns_resolve.h"
+#include "cache_lib.h"
+
+#define NFS_DNS_HASHBITS 4
+#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
+
+static struct cache_head *nfs_dns_table[NFS_DNS_HASHTBL_SIZE];
+
+struct nfs_dns_ent {
+ struct cache_head h;
+
+ char *hostname;
+ size_t namelen;
+
+ struct sockaddr_storage addr;
+ size_t addrlen;
+};
+
+
+static void nfs_dns_ent_init(struct cache_head *cnew,
+ struct cache_head *ckey)
+{
+ struct nfs_dns_ent *new;
+ struct nfs_dns_ent *key;
+
+ new = container_of(cnew, struct nfs_dns_ent, h);
+ key = container_of(ckey, struct nfs_dns_ent, h);
+
+ kfree(new->hostname);
+ new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
+ if (new->hostname) {
+ new->namelen = key->namelen;
+ memcpy(&new->addr, &key->addr, key->addrlen);
+ new->addrlen = key->addrlen;
+ } else {
+ new->namelen = 0;
+ new->addrlen = 0;
+ }
+}
+
+static void nfs_dns_ent_put(struct kref *ref)
+{
+ struct nfs_dns_ent *item;
+
+ item = container_of(ref, struct nfs_dns_ent, h.ref);
+ kfree(item->hostname);
+ kfree(item);
+}
+
+static struct cache_head *nfs_dns_ent_alloc(void)
+{
+ struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
+
+ if (item != NULL) {
+ item->hostname = NULL;
+ item->namelen = 0;
+ item->addrlen = 0;
+ return &item->h;
+ }
+ return NULL;
+};
+
+static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
+{
+ return hash_str(key->hostname, NFS_DNS_HASHBITS);
+}
+
+static void nfs_dns_request(struct cache_detail *cd,
+ struct cache_head *ch,
+ char **bpp, int *blen)
+{
+ struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
+
+ qword_add(bpp, blen, key->hostname);
+ (*bpp)[-1] = '\n';
+}
+
+static int nfs_dns_upcall(struct cache_detail *cd,
+ struct cache_head *ch)
+{
+ struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
+ int ret;
+
+ ret = nfs_cache_upcall(cd, key->hostname);
+ if (ret)
+ ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request);
+ return ret;
+}
+
+static int nfs_dns_match(struct cache_head *ca,
+ struct cache_head *cb)
+{
+ struct nfs_dns_ent *a;
+ struct nfs_dns_ent *b;
+
+ a = container_of(ca, struct nfs_dns_ent, h);
+ b = container_of(cb, struct nfs_dns_ent, h);
+
+ if (a->namelen == 0 || a->namelen != b->namelen)
+ return 0;
+ return memcmp(a->hostname, b->hostname, a->namelen) == 0;
+}
+
+static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
+ struct cache_head *h)
+{
+ struct nfs_dns_ent *item;
+ long ttl;
+
+ if (h == NULL) {
+ seq_puts(m, "# ip address hostname ttl\n");
+ return 0;
+ }
+ item = container_of(h, struct nfs_dns_ent, h);
+ ttl = (long)item->h.expiry_time - (long)get_seconds();
+ if (ttl < 0)
+ ttl = 0;
+
+ if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
+ char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
+
+ rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
+ seq_printf(m, "%15s ", buf);
+ } else
+ seq_puts(m, "<none> ");
+ seq_printf(m, "%15s %ld\n", item->hostname, ttl);
+ return 0;
+}
+
+struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
+ struct nfs_dns_ent *key)
+{
+ struct cache_head *ch;
+
+ ch = sunrpc_cache_lookup(cd,
+ &key->h,
+ nfs_dns_hash(key));
+ if (!ch)
+ return NULL;
+ return container_of(ch, struct nfs_dns_ent, h);
+}
+
+struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
+ struct nfs_dns_ent *new,
+ struct nfs_dns_ent *key)
+{
+ struct cache_head *ch;
+
+ ch = sunrpc_cache_update(cd,
+ &new->h, &key->h,
+ nfs_dns_hash(key));
+ if (!ch)
+ return NULL;
+ return container_of(ch, struct nfs_dns_ent, h);
+}
+
+static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
+{
+ char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
+ struct nfs_dns_ent key, *item;
+ unsigned long ttl;
+ ssize_t len;
+ int ret = -EINVAL;
+
+ if (buf[buflen-1] != '\n')
+ goto out;
+ buf[buflen-1] = '\0';
+
+ len = qword_get(&buf, buf1, sizeof(buf1));
+ if (len <= 0)
+ goto out;
+ key.addrlen = rpc_pton(buf1, len,
+ (struct sockaddr *)&key.addr,
+ sizeof(key.addr));
+
+ len = qword_get(&buf, buf1, sizeof(buf1));
+ if (len <= 0)
+ goto out;
+
+ key.hostname = buf1;
+ key.namelen = len;
+ memset(&key.h, 0, sizeof(key.h));
+
+ ttl = get_expiry(&buf);