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535cb8f319
The server shouldn't actually delete the struct nlm_host until it hits the garbage collector. In order to make that work correctly with the refcount API, we can bump the refcount by one, and then use refcount_dec_if_one() in the garbage collector. Signed-off-by: Trond Myklebust <trondmy@gmail.com> Acked-by: J. Bruce Fields <bfields@fieldses.org>
685 lines
17 KiB
C
685 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/lockd/host.c
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*
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* Management for NLM peer hosts. The nlm_host struct is shared
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* between client and server implementation. The only reason to
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* do so is to reduce code bloat.
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/addr.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/lockd/lockd.h>
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#include <linux/mutex.h>
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#include <linux/sunrpc/svc_xprt.h>
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#include <net/ipv6.h>
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#include "netns.h"
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#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
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#define NLM_HOST_NRHASH 32
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#define NLM_HOST_REBIND (60 * HZ)
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#define NLM_HOST_EXPIRE (300 * HZ)
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#define NLM_HOST_COLLECT (120 * HZ)
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static struct hlist_head nlm_server_hosts[NLM_HOST_NRHASH];
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static struct hlist_head nlm_client_hosts[NLM_HOST_NRHASH];
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#define for_each_host(host, chain, table) \
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for ((chain) = (table); \
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(chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
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hlist_for_each_entry((host), (chain), h_hash)
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#define for_each_host_safe(host, next, chain, table) \
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for ((chain) = (table); \
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(chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
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hlist_for_each_entry_safe((host), (next), \
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(chain), h_hash)
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static unsigned long nrhosts;
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static DEFINE_MUTEX(nlm_host_mutex);
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static void nlm_gc_hosts(struct net *net);
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struct nlm_lookup_host_info {
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const int server; /* search for server|client */
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const struct sockaddr *sap; /* address to search for */
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const size_t salen; /* it's length */
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const unsigned short protocol; /* transport to search for*/
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const u32 version; /* NLM version to search for */
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const char *hostname; /* remote's hostname */
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const size_t hostname_len; /* it's length */
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const int noresvport; /* use non-priv port */
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struct net *net; /* network namespace to bind */
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};
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/*
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* Hash function must work well on big- and little-endian platforms
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*/
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static unsigned int __nlm_hash32(const __be32 n)
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{
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unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
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return hash ^ (hash >> 8);
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}
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static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
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{
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const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
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return __nlm_hash32(sin->sin_addr.s_addr);
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}
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static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
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{
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const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
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const struct in6_addr addr = sin6->sin6_addr;
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return __nlm_hash32(addr.s6_addr32[0]) ^
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__nlm_hash32(addr.s6_addr32[1]) ^
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__nlm_hash32(addr.s6_addr32[2]) ^
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__nlm_hash32(addr.s6_addr32[3]);
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}
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static unsigned int nlm_hash_address(const struct sockaddr *sap)
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{
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unsigned int hash;
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switch (sap->sa_family) {
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case AF_INET:
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hash = __nlm_hash_addr4(sap);
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break;
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case AF_INET6:
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hash = __nlm_hash_addr6(sap);
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break;
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default:
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hash = 0;
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}
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return hash & (NLM_HOST_NRHASH - 1);
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}
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/*
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* Allocate and initialize an nlm_host. Common to both client and server.
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*/
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static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
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struct nsm_handle *nsm)
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{
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struct nlm_host *host = NULL;
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unsigned long now = jiffies;
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if (nsm != NULL)
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refcount_inc(&nsm->sm_count);
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else {
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host = NULL;
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nsm = nsm_get_handle(ni->net, ni->sap, ni->salen,
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ni->hostname, ni->hostname_len);
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if (unlikely(nsm == NULL)) {
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dprintk("lockd: %s failed; no nsm handle\n",
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__func__);
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goto out;
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}
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}
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host = kmalloc(sizeof(*host), GFP_KERNEL);
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if (unlikely(host == NULL)) {
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dprintk("lockd: %s failed; no memory\n", __func__);
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nsm_release(nsm);
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goto out;
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}
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memcpy(nlm_addr(host), ni->sap, ni->salen);
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host->h_addrlen = ni->salen;
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rpc_set_port(nlm_addr(host), 0);
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host->h_srcaddrlen = 0;
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host->h_rpcclnt = NULL;
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host->h_name = nsm->sm_name;
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host->h_version = ni->version;
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host->h_proto = ni->protocol;
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host->h_reclaiming = 0;
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host->h_server = ni->server;
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host->h_noresvport = ni->noresvport;
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host->h_inuse = 0;
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init_waitqueue_head(&host->h_gracewait);
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init_rwsem(&host->h_rwsem);
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host->h_state = 0;
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host->h_nsmstate = 0;
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host->h_pidcount = 0;
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refcount_set(&host->h_count, 1);
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mutex_init(&host->h_mutex);
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host->h_nextrebind = now + NLM_HOST_REBIND;
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host->h_expires = now + NLM_HOST_EXPIRE;
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INIT_LIST_HEAD(&host->h_lockowners);
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spin_lock_init(&host->h_lock);
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INIT_LIST_HEAD(&host->h_granted);
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INIT_LIST_HEAD(&host->h_reclaim);
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host->h_nsmhandle = nsm;
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host->h_addrbuf = nsm->sm_addrbuf;
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host->net = ni->net;
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strlcpy(host->nodename, utsname()->nodename, sizeof(host->nodename));
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out:
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return host;
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}
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/*
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* Destroy an nlm_host and free associated resources
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*
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* Caller must hold nlm_host_mutex.
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*/
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static void nlm_destroy_host_locked(struct nlm_host *host)
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{
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struct rpc_clnt *clnt;
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struct lockd_net *ln = net_generic(host->net, lockd_net_id);
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dprintk("lockd: destroy host %s\n", host->h_name);
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hlist_del_init(&host->h_hash);
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nsm_unmonitor(host);
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nsm_release(host->h_nsmhandle);
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clnt = host->h_rpcclnt;
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if (clnt != NULL)
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rpc_shutdown_client(clnt);
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kfree(host);
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ln->nrhosts--;
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nrhosts--;
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}
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/**
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* nlmclnt_lookup_host - Find an NLM host handle matching a remote server
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* @sap: network address of server
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* @salen: length of server address
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* @protocol: transport protocol to use
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* @version: NLM protocol version
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* @hostname: '\0'-terminated hostname of server
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* @noresvport: 1 if non-privileged port should be used
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*
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* Returns an nlm_host structure that matches the passed-in
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* [server address, transport protocol, NLM version, server hostname].
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* If one doesn't already exist in the host cache, a new handle is
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* created and returned.
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*/
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struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
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const size_t salen,
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const unsigned short protocol,
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const u32 version,
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const char *hostname,
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int noresvport,
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struct net *net)
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{
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struct nlm_lookup_host_info ni = {
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.server = 0,
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.sap = sap,
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.salen = salen,
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.protocol = protocol,
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.version = version,
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.hostname = hostname,
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.hostname_len = strlen(hostname),
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.noresvport = noresvport,
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.net = net,
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};
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struct hlist_head *chain;
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struct nlm_host *host;
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struct nsm_handle *nsm = NULL;
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struct lockd_net *ln = net_generic(net, lockd_net_id);
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dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
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(hostname ? hostname : "<none>"), version,
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(protocol == IPPROTO_UDP ? "udp" : "tcp"));
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mutex_lock(&nlm_host_mutex);
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chain = &nlm_client_hosts[nlm_hash_address(sap)];
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hlist_for_each_entry(host, chain, h_hash) {
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if (host->net != net)
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continue;
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if (!rpc_cmp_addr(nlm_addr(host), sap))
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continue;
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/* Same address. Share an NSM handle if we already have one */
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if (nsm == NULL)
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nsm = host->h_nsmhandle;
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if (host->h_proto != protocol)
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continue;
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if (host->h_version != version)
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continue;
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nlm_get_host(host);
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dprintk("lockd: %s found host %s (%s)\n", __func__,
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host->h_name, host->h_addrbuf);
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goto out;
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}
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host = nlm_alloc_host(&ni, nsm);
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if (unlikely(host == NULL))
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goto out;
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hlist_add_head(&host->h_hash, chain);
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ln->nrhosts++;
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nrhosts++;
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dprintk("lockd: %s created host %s (%s)\n", __func__,
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host->h_name, host->h_addrbuf);
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out:
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mutex_unlock(&nlm_host_mutex);
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return host;
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}
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/**
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* nlmclnt_release_host - release client nlm_host
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* @host: nlm_host to release
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*
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*/
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void nlmclnt_release_host(struct nlm_host *host)
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{
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if (host == NULL)
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return;
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dprintk("lockd: release client host %s\n", host->h_name);
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WARN_ON_ONCE(host->h_server);
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if (refcount_dec_and_test(&host->h_count)) {
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WARN_ON_ONCE(!list_empty(&host->h_lockowners));
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WARN_ON_ONCE(!list_empty(&host->h_granted));
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WARN_ON_ONCE(!list_empty(&host->h_reclaim));
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mutex_lock(&nlm_host_mutex);
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nlm_destroy_host_locked(host);
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mutex_unlock(&nlm_host_mutex);
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}
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}
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/**
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* nlmsvc_lookup_host - Find an NLM host handle matching a remote client
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* @rqstp: incoming NLM request
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* @hostname: name of client host
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* @hostname_len: length of client hostname
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*
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* Returns an nlm_host structure that matches the [client address,
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* transport protocol, NLM version, client hostname] of the passed-in
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* NLM request. If one doesn't already exist in the host cache, a
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* new handle is created and returned.
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*
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* Before possibly creating a new nlm_host, construct a sockaddr
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* for a specific source address in case the local system has
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* multiple network addresses. The family of the address in
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* rq_daddr is guaranteed to be the same as the family of the
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* address in rq_addr, so it's safe to use the same family for
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* the source address.
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*/
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struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
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const char *hostname,
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const size_t hostname_len)
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{
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struct hlist_head *chain;
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struct nlm_host *host = NULL;
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struct nsm_handle *nsm = NULL;
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struct sockaddr *src_sap = svc_daddr(rqstp);
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size_t src_len = rqstp->rq_daddrlen;
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struct net *net = SVC_NET(rqstp);
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struct nlm_lookup_host_info ni = {
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.server = 1,
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.sap = svc_addr(rqstp),
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.salen = rqstp->rq_addrlen,
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.protocol = rqstp->rq_prot,
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.version = rqstp->rq_vers,
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.hostname = hostname,
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.hostname_len = hostname_len,
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.net = net,
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};
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struct lockd_net *ln = net_generic(net, lockd_net_id);
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dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
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(int)hostname_len, hostname, rqstp->rq_vers,
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(rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
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mutex_lock(&nlm_host_mutex);
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if (time_after_eq(jiffies, ln->next_gc))
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nlm_gc_hosts(net);
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chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
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hlist_for_each_entry(host, chain, h_hash) {
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if (host->net != net)
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continue;
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if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
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continue;
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/* Same address. Share an NSM handle if we already have one */
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if (nsm == NULL)
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nsm = host->h_nsmhandle;
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if (host->h_proto != ni.protocol)
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continue;
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if (host->h_version != ni.version)
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continue;
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if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
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continue;
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/* Move to head of hash chain. */
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hlist_del(&host->h_hash);
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hlist_add_head(&host->h_hash, chain);
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nlm_get_host(host);
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dprintk("lockd: %s found host %s (%s)\n",
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__func__, host->h_name, host->h_addrbuf);
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goto out;
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}
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host = nlm_alloc_host(&ni, nsm);
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if (unlikely(host == NULL))
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goto out;
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memcpy(nlm_srcaddr(host), src_sap, src_len);
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host->h_srcaddrlen = src_len;
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hlist_add_head(&host->h_hash, chain);
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ln->nrhosts++;
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nrhosts++;
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refcount_inc(&host->h_count);
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dprintk("lockd: %s created host %s (%s)\n",
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__func__, host->h_name, host->h_addrbuf);
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out:
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mutex_unlock(&nlm_host_mutex);
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return host;
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}
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/**
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* nlmsvc_release_host - release server nlm_host
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* @host: nlm_host to release
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*
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* Host is destroyed later in nlm_gc_host().
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*/
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void nlmsvc_release_host(struct nlm_host *host)
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{
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if (host == NULL)
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return;
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dprintk("lockd: release server host %s\n", host->h_name);
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WARN_ON_ONCE(!host->h_server);
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refcount_dec(&host->h_count);
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}
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/*
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* Create the NLM RPC client for an NLM peer
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*/
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struct rpc_clnt *
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nlm_bind_host(struct nlm_host *host)
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{
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struct rpc_clnt *clnt;
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dprintk("lockd: nlm_bind_host %s (%s)\n",
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host->h_name, host->h_addrbuf);
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/* Lock host handle */
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mutex_lock(&host->h_mutex);
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/* If we've already created an RPC client, check whether
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* RPC rebind is required
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*/
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if ((clnt = host->h_rpcclnt) != NULL) {
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if (time_after_eq(jiffies, host->h_nextrebind)) {
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rpc_force_rebind(clnt);
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host->h_nextrebind = jiffies + NLM_HOST_REBIND;
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dprintk("lockd: next rebind in %lu jiffies\n",
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host->h_nextrebind - jiffies);
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}
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} else {
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unsigned long increment = nlmsvc_timeout;
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struct rpc_timeout timeparms = {
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.to_initval = increment,
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.to_increment = increment,
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.to_maxval = increment * 6UL,
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.to_retries = 5U,
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};
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struct rpc_create_args args = {
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.net = host->net,
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.protocol = host->h_proto,
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.address = nlm_addr(host),
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.addrsize = host->h_addrlen,
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.timeout = &timeparms,
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.servername = host->h_name,
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.program = &nlm_program,
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.version = host->h_version,
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.authflavor = RPC_AUTH_UNIX,
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.flags = (RPC_CLNT_CREATE_NOPING |
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RPC_CLNT_CREATE_AUTOBIND),
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};
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/*
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* lockd retries server side blocks automatically so we want
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* those to be soft RPC calls. Client side calls need to be
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* hard RPC tasks.
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*/
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if (!host->h_server)
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args.flags |= RPC_CLNT_CREATE_HARDRTRY;
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if (host->h_noresvport)
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args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
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if (host->h_srcaddrlen)
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args.saddress = nlm_srcaddr(host);
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clnt = rpc_create(&args);
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if (!IS_ERR(clnt))
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host->h_rpcclnt = clnt;
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else {
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printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
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clnt = NULL;
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}
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}
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mutex_unlock(&host->h_mutex);
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return clnt;
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}
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/*
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* Force a portmap lookup of the remote lockd port
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*/
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void
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nlm_rebind_host(struct nlm_host *host)
|
|
{
|
|
dprintk("lockd: rebind host %s\n", host->h_name);
|
|
if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
|
|
rpc_force_rebind(host->h_rpcclnt);
|
|
host->h_nextrebind = jiffies + NLM_HOST_REBIND;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Increment NLM host count
|
|
*/
|
|
struct nlm_host * nlm_get_host(struct nlm_host *host)
|
|
{
|
|
if (host) {
|
|
dprintk("lockd: get host %s\n", host->h_name);
|
|
refcount_inc(&host->h_count);
|
|
host->h_expires = jiffies + NLM_HOST_EXPIRE;
|
|
}
|
|
return host;
|
|
}
|
|
|
|
static struct nlm_host *next_host_state(struct hlist_head *cache,
|
|
struct nsm_handle *nsm,
|
|
const struct nlm_reboot *info)
|
|
{
|
|
struct nlm_host *host;
|
|
struct hlist_head *chain;
|
|
|
|
mutex_lock(&nlm_host_mutex);
|
|
for_each_host(host, chain, cache) {
|
|
if (host->h_nsmhandle == nsm
|
|
&& host->h_nsmstate != info->state) {
|
|
host->h_nsmstate = info->state;
|
|
host->h_state++;
|
|
|
|
nlm_get_host(host);
|
|
mutex_unlock(&nlm_host_mutex);
|
|
return host;
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&nlm_host_mutex);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* nlm_host_rebooted - Release all resources held by rebooted host
|
|
* @net: network namespace
|
|
* @info: pointer to decoded results of NLM_SM_NOTIFY call
|
|
*
|
|
* We were notified that the specified host has rebooted. Release
|
|
* all resources held by that peer.
|
|
*/
|
|
void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info)
|
|
{
|
|
struct nsm_handle *nsm;
|
|
struct nlm_host *host;
|
|
|
|
nsm = nsm_reboot_lookup(net, info);
|
|
if (unlikely(nsm == NULL))
|
|
return;
|
|
|
|
/* Mark all hosts tied to this NSM state as having rebooted.
|
|
* We run the loop repeatedly, because we drop the host table
|
|
* lock for this.
|
|
* To avoid processing a host several times, we match the nsmstate.
|
|
*/
|
|
while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
|
|
nlmsvc_free_host_resources(host);
|
|
nlmsvc_release_host(host);
|
|
}
|
|
while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
|
|
nlmclnt_recovery(host);
|
|
nlmclnt_release_host(host);
|
|
}
|
|
|
|
nsm_release(nsm);
|
|
}
|
|
|
|
static void nlm_complain_hosts(struct net *net)
|
|
{
|
|
struct hlist_head *chain;
|
|
struct nlm_host *host;
|
|
|
|
if (net) {
|
|
struct lockd_net *ln = net_generic(net, lockd_net_id);
|
|
|
|
if (ln->nrhosts == 0)
|
|
return;
|
|
pr_warn("lockd: couldn't shutdown host module for net %x!\n",
|
|
net->ns.inum);
|
|
dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts,
|
|
net->ns.inum);
|
|
} else {
|
|
if (nrhosts == 0)
|
|
return;
|
|
printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
|
|
dprintk("lockd: %lu hosts left:\n", nrhosts);
|
|
}
|
|
|
|
for_each_host(host, chain, nlm_server_hosts) {
|
|
if (net && host->net != net)
|
|
continue;
|
|
dprintk(" %s (cnt %d use %d exp %ld net %x)\n",
|
|
host->h_name, refcount_read(&host->h_count),
|
|
host->h_inuse, host->h_expires, host->net->ns.inum);
|
|
}
|
|
}
|
|
|
|
void
|
|
nlm_shutdown_hosts_net(struct net *net)
|
|
{
|
|
struct hlist_head *chain;
|
|
struct nlm_host *host;
|
|
|
|
mutex_lock(&nlm_host_mutex);
|
|
|
|
/* First, make all hosts eligible for gc */
|
|
dprintk("lockd: nuking all hosts in net %x...\n",
|
|
net ? net->ns.inum : 0);
|
|
for_each_host(host, chain, nlm_server_hosts) {
|
|
if (net && host->net != net)
|
|
continue;
|
|
host->h_expires = jiffies - 1;
|
|
if (host->h_rpcclnt) {
|
|
rpc_shutdown_client(host->h_rpcclnt);
|
|
host->h_rpcclnt = NULL;
|
|
}
|
|
}
|
|
|
|
/* Then, perform a garbage collection pass */
|
|
nlm_gc_hosts(net);
|
|
nlm_complain_hosts(net);
|
|
mutex_unlock(&nlm_host_mutex);
|
|
}
|
|
|
|
/*
|
|
* Shut down the hosts module.
|
|
* Note that this routine is called only at server shutdown time.
|
|
*/
|
|
void
|
|
nlm_shutdown_hosts(void)
|
|
{
|
|
dprintk("lockd: shutting down host module\n");
|
|
nlm_shutdown_hosts_net(NULL);
|
|
}
|
|
|
|
/*
|
|
* Garbage collect any unused NLM hosts.
|
|
* This GC combines reference counting for async operations with
|
|
* mark & sweep for resources held by remote clients.
|
|
*/
|
|
static void
|
|
nlm_gc_hosts(struct net *net)
|
|
{
|
|
struct hlist_head *chain;
|
|
struct hlist_node *next;
|
|
struct nlm_host *host;
|
|
|
|
dprintk("lockd: host garbage collection for net %x\n",
|
|
net ? net->ns.inum : 0);
|
|
for_each_host(host, chain, nlm_server_hosts) {
|
|
if (net && host->net != net)
|
|
continue;
|
|
host->h_inuse = 0;
|
|
}
|
|
|
|
/* Mark all hosts that hold locks, blocks or shares */
|
|
nlmsvc_mark_resources(net);
|
|
|
|
for_each_host_safe(host, next, chain, nlm_server_hosts) {
|
|
if (net && host->net != net)
|
|
continue;
|
|
if (host->h_inuse || time_before(jiffies, host->h_expires)) {
|
|
dprintk("nlm_gc_hosts skipping %s "
|
|
"(cnt %d use %d exp %ld net %x)\n",
|
|
host->h_name, refcount_read(&host->h_count),
|
|
host->h_inuse, host->h_expires,
|
|
host->net->ns.inum);
|
|
continue;
|
|
}
|
|
if (refcount_dec_if_one(&host->h_count))
|
|
nlm_destroy_host_locked(host);
|
|
}
|
|
|
|
if (net) {
|
|
struct lockd_net *ln = net_generic(net, lockd_net_id);
|
|
|
|
ln->next_gc = jiffies + NLM_HOST_COLLECT;
|
|
}
|
|
}
|