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158 lines
3.8 KiB
158 lines
3.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/nfs/cache_lib.c |
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* |
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* Helper routines for the NFS client caches |
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* |
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* Copyright (c) 2009 Trond Myklebust <[email protected]> |
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*/ |
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#include <linux/kmod.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/mount.h> |
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#include <linux/namei.h> |
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#include <linux/slab.h> |
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#include <linux/sunrpc/cache.h> |
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#include <linux/sunrpc/rpc_pipe_fs.h> |
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#include <net/net_namespace.h> |
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#include "cache_lib.h" |
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#define NFS_CACHE_UPCALL_PATHLEN 256 |
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#define NFS_CACHE_UPCALL_TIMEOUT 15 |
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static char nfs_cache_getent_prog[NFS_CACHE_UPCALL_PATHLEN] = |
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"/sbin/nfs_cache_getent"; |
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static unsigned long nfs_cache_getent_timeout = NFS_CACHE_UPCALL_TIMEOUT; |
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module_param_string(cache_getent, nfs_cache_getent_prog, |
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sizeof(nfs_cache_getent_prog), 0600); |
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MODULE_PARM_DESC(cache_getent, "Path to the client cache upcall program"); |
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module_param_named(cache_getent_timeout, nfs_cache_getent_timeout, ulong, 0600); |
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MODULE_PARM_DESC(cache_getent_timeout, "Timeout (in seconds) after which " |
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"the cache upcall is assumed to have failed"); |
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int nfs_cache_upcall(struct cache_detail *cd, char *entry_name) |
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{ |
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static char *envp[] = { "HOME=/", |
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"TERM=linux", |
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"PATH=/sbin:/usr/sbin:/bin:/usr/bin", |
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NULL |
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}; |
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char *argv[] = { |
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nfs_cache_getent_prog, |
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cd->name, |
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entry_name, |
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NULL |
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}; |
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int ret = -EACCES; |
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if (nfs_cache_getent_prog[0] == '\0') |
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goto out; |
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ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); |
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/* |
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* Disable the upcall mechanism if we're getting an ENOENT or |
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* EACCES error. The admin can re-enable it on the fly by using |
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* sysfs to set the 'cache_getent' parameter once the problem |
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* has been fixed. |
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*/ |
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if (ret == -ENOENT || ret == -EACCES) |
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nfs_cache_getent_prog[0] = '\0'; |
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out: |
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return ret > 0 ? 0 : ret; |
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} |
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/* |
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* Deferred request handling |
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*/ |
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void nfs_cache_defer_req_put(struct nfs_cache_defer_req *dreq) |
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{ |
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if (refcount_dec_and_test(&dreq->count)) |
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kfree(dreq); |
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} |
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static void nfs_dns_cache_revisit(struct cache_deferred_req *d, int toomany) |
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{ |
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struct nfs_cache_defer_req *dreq; |
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dreq = container_of(d, struct nfs_cache_defer_req, deferred_req); |
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complete(&dreq->completion); |
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nfs_cache_defer_req_put(dreq); |
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} |
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static struct cache_deferred_req *nfs_dns_cache_defer(struct cache_req *req) |
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{ |
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struct nfs_cache_defer_req *dreq; |
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dreq = container_of(req, struct nfs_cache_defer_req, req); |
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dreq->deferred_req.revisit = nfs_dns_cache_revisit; |
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refcount_inc(&dreq->count); |
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return &dreq->deferred_req; |
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} |
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struct nfs_cache_defer_req *nfs_cache_defer_req_alloc(void) |
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{ |
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struct nfs_cache_defer_req *dreq; |
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dreq = kzalloc(sizeof(*dreq), GFP_KERNEL); |
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if (dreq) { |
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init_completion(&dreq->completion); |
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refcount_set(&dreq->count, 1); |
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dreq->req.defer = nfs_dns_cache_defer; |
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} |
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return dreq; |
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} |
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int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq) |
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{ |
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if (wait_for_completion_timeout(&dreq->completion, |
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nfs_cache_getent_timeout * HZ) == 0) |
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return -ETIMEDOUT; |
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return 0; |
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} |
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int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd) |
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{ |
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int ret; |
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struct dentry *dir; |
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dir = rpc_d_lookup_sb(sb, "cache"); |
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ret = sunrpc_cache_register_pipefs(dir, cd->name, 0600, cd); |
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dput(dir); |
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return ret; |
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} |
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int nfs_cache_register_net(struct net *net, struct cache_detail *cd) |
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{ |
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struct super_block *pipefs_sb; |
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int ret = 0; |
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sunrpc_init_cache_detail(cd); |
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pipefs_sb = rpc_get_sb_net(net); |
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if (pipefs_sb) { |
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ret = nfs_cache_register_sb(pipefs_sb, cd); |
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rpc_put_sb_net(net); |
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if (ret) |
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sunrpc_destroy_cache_detail(cd); |
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} |
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return ret; |
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} |
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void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd) |
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{ |
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sunrpc_cache_unregister_pipefs(cd); |
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} |
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void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd) |
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{ |
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struct super_block *pipefs_sb; |
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pipefs_sb = rpc_get_sb_net(net); |
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if (pipefs_sb) { |
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nfs_cache_unregister_sb(pipefs_sb, cd); |
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rpc_put_sb_net(net); |
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} |
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sunrpc_destroy_cache_detail(cd); |
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}
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