1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
2e571cbf1STrond Myklebust /*
3e571cbf1STrond Myklebust * linux/fs/nfs/cache_lib.c
4e571cbf1STrond Myklebust *
5e571cbf1STrond Myklebust * Helper routines for the NFS client caches
6e571cbf1STrond Myklebust *
7e571cbf1STrond Myklebust * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
8e571cbf1STrond Myklebust */
9e571cbf1STrond Myklebust #include <linux/kmod.h>
10e571cbf1STrond Myklebust #include <linux/module.h>
11e571cbf1STrond Myklebust #include <linux/moduleparam.h>
12e571cbf1STrond Myklebust #include <linux/mount.h>
13e571cbf1STrond Myklebust #include <linux/namei.h>
145a0e3ad6STejun Heo #include <linux/slab.h>
15e571cbf1STrond Myklebust #include <linux/sunrpc/cache.h>
16e571cbf1STrond Myklebust #include <linux/sunrpc/rpc_pipe_fs.h>
175c1cacb1SStanislav Kinsbursky #include <net/net_namespace.h>
18e571cbf1STrond Myklebust
19e571cbf1STrond Myklebust #include "cache_lib.h"
20e571cbf1STrond Myklebust
21e571cbf1STrond Myklebust #define NFS_CACHE_UPCALL_PATHLEN 256
22e571cbf1STrond Myklebust #define NFS_CACHE_UPCALL_TIMEOUT 15
23e571cbf1STrond Myklebust
24e571cbf1STrond Myklebust static char nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] =
25e571cbf1STrond Myklebust "/sbin/nfs_cache_getent";
26e571cbf1STrond Myklebust static unsigned long nfs_cache_getent_timeout = NFS_CACHE_UPCALL_TIMEOUT;
27e571cbf1STrond Myklebust
28e571cbf1STrond Myklebust module_param_string(cache_getent, nfs_cache_getent_prog,
29e571cbf1STrond Myklebust sizeof(nfs_cache_getent_prog), 0600);
30e571cbf1STrond Myklebust MODULE_PARM_DESC(cache_getent, "Path to the client cache upcall program");
31e571cbf1STrond Myklebust module_param_named(cache_getent_timeout, nfs_cache_getent_timeout, ulong, 0600);
32e571cbf1STrond Myklebust MODULE_PARM_DESC(cache_getent_timeout, "Timeout (in seconds) after which "
33e571cbf1STrond Myklebust "the cache upcall is assumed to have failed");
34e571cbf1STrond Myklebust
nfs_cache_upcall(struct cache_detail * cd,char * entry_name)35e571cbf1STrond Myklebust int nfs_cache_upcall(struct cache_detail *cd, char *entry_name)
36e571cbf1STrond Myklebust {
37e571cbf1STrond Myklebust static char *envp[] = { "HOME=/",
38e571cbf1STrond Myklebust "TERM=linux",
39e571cbf1STrond Myklebust "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
40e571cbf1STrond Myklebust NULL
41e571cbf1STrond Myklebust };
42e571cbf1STrond Myklebust char *argv[] = {
43e571cbf1STrond Myklebust nfs_cache_getent_prog,
44e571cbf1STrond Myklebust cd->name,
45e571cbf1STrond Myklebust entry_name,
46e571cbf1STrond Myklebust NULL
47e571cbf1STrond Myklebust };
48e571cbf1STrond Myklebust int ret = -EACCES;
49e571cbf1STrond Myklebust
50e571cbf1STrond Myklebust if (nfs_cache_getent_prog[0] == '\0')
51e571cbf1STrond Myklebust goto out;
52e571cbf1STrond Myklebust ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
53e571cbf1STrond Myklebust /*
54e571cbf1STrond Myklebust * Disable the upcall mechanism if we're getting an ENOENT or
55e571cbf1STrond Myklebust * EACCES error. The admin can re-enable it on the fly by using
56e571cbf1STrond Myklebust * sysfs to set the 'cache_getent' parameter once the problem
57e571cbf1STrond Myklebust * has been fixed.
58e571cbf1STrond Myklebust */
59e571cbf1STrond Myklebust if (ret == -ENOENT || ret == -EACCES)
60e571cbf1STrond Myklebust nfs_cache_getent_prog[0] = '\0';
61e571cbf1STrond Myklebust out:
62e571cbf1STrond Myklebust return ret > 0 ? 0 : ret;
63e571cbf1STrond Myklebust }
64e571cbf1STrond Myklebust
65e571cbf1STrond Myklebust /*
66e571cbf1STrond Myklebust * Deferred request handling
67e571cbf1STrond Myklebust */
nfs_cache_defer_req_put(struct nfs_cache_defer_req * dreq)68e571cbf1STrond Myklebust void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq)
69e571cbf1STrond Myklebust {
70*0896cadeSElena Reshetova if (refcount_dec_and_test(&dreq->count))
71e571cbf1STrond Myklebust kfree(dreq);
72e571cbf1STrond Myklebust }
73e571cbf1STrond Myklebust
nfs_dns_cache_revisit(struct cache_deferred_req * d,int toomany)74e571cbf1STrond Myklebust static void nfs_dns_cache_revisit(struct cache_deferred_req *d, int toomany)
75e571cbf1STrond Myklebust {
76e571cbf1STrond Myklebust struct nfs_cache_defer_req *dreq;
77e571cbf1STrond Myklebust
78e571cbf1STrond Myklebust dreq = container_of(d, struct nfs_cache_defer_req, deferred_req);
79e571cbf1STrond Myklebust
802a446a5dSDaniel Wagner complete(&dreq->completion);
81e571cbf1STrond Myklebust nfs_cache_defer_req_put(dreq);
82e571cbf1STrond Myklebust }
83e571cbf1STrond Myklebust
nfs_dns_cache_defer(struct cache_req * req)84e571cbf1STrond Myklebust static struct cache_deferred_req *nfs_dns_cache_defer(struct cache_req *req)
85e571cbf1STrond Myklebust {
86e571cbf1STrond Myklebust struct nfs_cache_defer_req *dreq;
87e571cbf1STrond Myklebust
88e571cbf1STrond Myklebust dreq = container_of(req, struct nfs_cache_defer_req, req);
89e571cbf1STrond Myklebust dreq->deferred_req.revisit = nfs_dns_cache_revisit;
90*0896cadeSElena Reshetova refcount_inc(&dreq->count);
91e571cbf1STrond Myklebust
92e571cbf1STrond Myklebust return &dreq->deferred_req;
93e571cbf1STrond Myklebust }
94e571cbf1STrond Myklebust
nfs_cache_defer_req_alloc(void)95e571cbf1STrond Myklebust struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void)
96e571cbf1STrond Myklebust {
97e571cbf1STrond Myklebust struct nfs_cache_defer_req *dreq;
98e571cbf1STrond Myklebust
99e571cbf1STrond Myklebust dreq = kzalloc(sizeof(*dreq), GFP_KERNEL);
100e571cbf1STrond Myklebust if (dreq) {
101e571cbf1STrond Myklebust init_completion(&dreq->completion);
102*0896cadeSElena Reshetova refcount_set(&dreq->count, 1);
103e571cbf1STrond Myklebust dreq->req.defer = nfs_dns_cache_defer;
104e571cbf1STrond Myklebust }
105e571cbf1STrond Myklebust return dreq;
106e571cbf1STrond Myklebust }
107e571cbf1STrond Myklebust
nfs_cache_wait_for_upcall(struct nfs_cache_defer_req * dreq)108e571cbf1STrond Myklebust int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
109e571cbf1STrond Myklebust {
110e571cbf1STrond Myklebust if (wait_for_completion_timeout(&dreq->completion,
111e571cbf1STrond Myklebust nfs_cache_getent_timeout * HZ) == 0)
112e571cbf1STrond Myklebust return -ETIMEDOUT;
113e571cbf1STrond Myklebust return 0;
114e571cbf1STrond Myklebust }
115e571cbf1STrond Myklebust
nfs_cache_register_sb(struct super_block * sb,struct cache_detail * cd)1169df69c81SStanislav Kinsbursky int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
1175c1cacb1SStanislav Kinsbursky {
1185c1cacb1SStanislav Kinsbursky int ret;
1195c1cacb1SStanislav Kinsbursky struct dentry *dir;
1205c1cacb1SStanislav Kinsbursky
1215c1cacb1SStanislav Kinsbursky dir = rpc_d_lookup_sb(sb, "cache");
1225c1cacb1SStanislav Kinsbursky ret = sunrpc_cache_register_pipefs(dir, cd->name, 0600, cd);
1235c1cacb1SStanislav Kinsbursky dput(dir);
1245c1cacb1SStanislav Kinsbursky return ret;
1255c1cacb1SStanislav Kinsbursky }
1265c1cacb1SStanislav Kinsbursky
nfs_cache_register_net(struct net * net,struct cache_detail * cd)1275c1cacb1SStanislav Kinsbursky int nfs_cache_register_net(struct net *net, struct cache_detail *cd)
128e571cbf1STrond Myklebust {
1295c1cacb1SStanislav Kinsbursky struct super_block *pipefs_sb;
13039cb67b9SStanislav Kinsbursky int ret = 0;
131e571cbf1STrond Myklebust
132462b8f6bSStanislav Kinsbursky sunrpc_init_cache_detail(cd);
1335c1cacb1SStanislav Kinsbursky pipefs_sb = rpc_get_sb_net(net);
13439cb67b9SStanislav Kinsbursky if (pipefs_sb) {
1355c1cacb1SStanislav Kinsbursky ret = nfs_cache_register_sb(pipefs_sb, cd);
1365c1cacb1SStanislav Kinsbursky rpc_put_sb_net(net);
137462b8f6bSStanislav Kinsbursky if (ret)
138462b8f6bSStanislav Kinsbursky sunrpc_destroy_cache_detail(cd);
13939cb67b9SStanislav Kinsbursky }
140e571cbf1STrond Myklebust return ret;
141e571cbf1STrond Myklebust }
142e571cbf1STrond Myklebust
nfs_cache_unregister_sb(struct super_block * sb,struct cache_detail * cd)1439df69c81SStanislav Kinsbursky void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
144e571cbf1STrond Myklebust {
145e571cbf1STrond Myklebust sunrpc_cache_unregister_pipefs(cd);
1465c1cacb1SStanislav Kinsbursky }
1475c1cacb1SStanislav Kinsbursky
nfs_cache_unregister_net(struct net * net,struct cache_detail * cd)1485c1cacb1SStanislav Kinsbursky void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd)
1495c1cacb1SStanislav Kinsbursky {
1505c1cacb1SStanislav Kinsbursky struct super_block *pipefs_sb;
1515c1cacb1SStanislav Kinsbursky
1525c1cacb1SStanislav Kinsbursky pipefs_sb = rpc_get_sb_net(net);
1535c1cacb1SStanislav Kinsbursky if (pipefs_sb) {
1545c1cacb1SStanislav Kinsbursky nfs_cache_unregister_sb(pipefs_sb, cd);
1555c1cacb1SStanislav Kinsbursky rpc_put_sb_net(net);
1565c1cacb1SStanislav Kinsbursky }
1579222b955SStanislav Kinsbursky sunrpc_destroy_cache_detail(cd);
1589222b955SStanislav Kinsbursky }
159