/* * Central processing for nfsd. * * Authors: Olaf Kirch (okir@monad.swb.de) * * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de> */ #include <linux/sched.h> #include <linux/freezer.h> #include <linux/fs_struct.h> #include <linux/swap.h> #include <linux/sunrpc/stats.h> #include <linux/sunrpc/svcsock.h> #include <linux/lockd/bind.h> #include <linux/nfsacl.h> #include <linux/seq_file.h> #include <net/net_namespace.h> #include "nfsd.h" #include "cache.h" #include "vfs.h" #define NFSDDBG_FACILITY NFSDDBG_SVC extern struct svc_program nfsd_program; static int nfsd(void *vrqstp); struct timeval nfssvc_boot; /* * nfsd_mutex protects nfsd_serv -- both the pointer itself and the members * of the svc_serv struct. In particular, ->sv_nrthreads but also to some * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt * * If (out side the lock) nfsd_serv is non-NULL, then it must point to a * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number * of nfsd threads must exist and each must listed in ->sp_all_threads in each * entry of ->sv_pools[]. * * Transitions of the thread count between zero and non-zero are of particular * interest since the svc_serv needs to be created and initialized at that * point, or freed. * * Finally, the nfsd_mutex also protects some of the global variables that are * accessed when nfsd starts and that are settable via the write_* routines in * nfsctl.c. In particular: * * user_recovery_dirname * user_lease_time * nfsd_versions */ DEFINE_MUTEX(nfsd_mutex); struct svc_serv *nfsd_serv; /* * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used. * nfsd_drc_max_pages limits the total amount of memory available for * version 4.1 DRC caches. * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage. */ spinlock_t nfsd_drc_lock; unsigned int nfsd_drc_max_mem; unsigned int nfsd_drc_mem_used; #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) static struct svc_stat nfsd_acl_svcstats; static struct svc_version * nfsd_acl_version[] = { [2] = &nfsd_acl_version2, [3] = &nfsd_acl_version3, }; #define NFSD_ACL_MINVERS 2 #define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version) static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS]; static struct svc_program nfsd_acl_program = { .pg_prog = NFS_ACL_PROGRAM, .pg_nvers = NFSD_ACL_NRVERS, .pg_vers = nfsd_acl_versions, .pg_name = "nfsacl", .pg_class = "nfsd", .pg_stats = &nfsd_acl_svcstats, .pg_authenticate = &svc_set_client, }; static struct svc_stat nfsd_acl_svcstats = { .program = &nfsd_acl_program, }; #endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */ static struct svc_version * nfsd_version[] = { [2] = &nfsd_version2, #if defined(CONFIG_NFSD_V3) [3] = &nfsd_version3, #endif #if defined(CONFIG_NFSD_V4) [4] = &nfsd_version4, #endif }; #define NFSD_MINVERS 2 #define NFSD_NRVERS ARRAY_SIZE(nfsd_version) static struct svc_version *nfsd_versions[NFSD_NRVERS]; struct svc_program nfsd_program = { #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) .pg_next = &nfsd_acl_program, #endif .pg_prog = NFS_PROGRAM, /* program number */ .pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */ .pg_vers = nfsd_versions, /* version table */ .pg_name = "nfsd", /* program name */ .pg_class = "nfsd", /* authentication class */ .pg_stats = &nfsd_svcstats, /* version table */ .pg_authenticate = &svc_set_client, /* export authentication */ }; u32 nfsd_supported_minorversion; int nfsd_vers(int vers, enum vers_op change) { if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS) return 0; switch(change) { case NFSD_SET: nfsd_versions[vers] = nfsd_version[vers]; #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) if (vers < NFSD_ACL_NRVERS) nfsd_acl_versions[vers] = nfsd_acl_version[vers]; #endif break; case NFSD_CLEAR: nfsd_versions[vers] = NULL; #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) if (vers < NFSD_ACL_NRVERS) nfsd_acl_versions[vers] = NULL; #endif break; case NFSD_TEST: return nfsd_versions[vers] != NULL; case NFSD_AVAIL: return nfsd_version[vers] != NULL; } return 0; } int nfsd_minorversion(u32 minorversion, enum vers_op change) { if (minorversion > NFSD_SUPPORTED_MINOR_VERSION) return -1; switch(change) { case NFSD_SET: nfsd_supported_minorversion = minorversion; break; case NFSD_CLEAR: if (minorversion == 0) return -1; nfsd_supported_minorversion = minorversion - 1; break; case NFSD_TEST: return minorversion <= nfsd_supported_minorversion; case NFSD_AVAIL: return minorversion <= NFSD_SUPPORTED_MINOR_VERSION; } return 0; } /* * Maximum number of nfsd processes */ #define NFSD_MAXSERVS 8192 int nfsd_nrthreads(void) { int rv = 0; mutex_lock(&nfsd_mutex); if (nfsd_serv) rv = nfsd_serv->sv_nrthreads; mutex_unlock(&nfsd_mutex); return rv; } static int nfsd_init_socks(int port) { int error; if (!list_empty(&nfsd_serv->sv_permsocks)) return 0; error = svc_create_xprt(nfsd_serv, "udp", &init_net, PF_INET, port, SVC_SOCK_DEFAULTS); if (error < 0) return error; error = svc_create_xprt(nfsd_serv, "tcp", &init_net, PF_INET, port, SVC_SOCK_DEFAULTS); if (error < 0) return error; return 0; } static bool nfsd_up = false; static int nfsd_startup(unsigned short port, int nrservs) { int ret; if (nfsd_up) return 0; /* * Readahead param cache - will no-op if it already exists. * (Note therefore results will be suboptimal if number of * threads is modified after nfsd start.) */ ret = nfsd_racache_init(2*nrservs); if (ret) return ret; ret = nfsd_init_socks(port); if (ret) goto out_racache; ret = lockd_up(); if (ret) goto out_racache; ret = nfs4_state_start(); if (ret) goto out_lockd; nfsd_up = true; return 0; out_lockd: lockd_down(); out_racache: nfsd_racache_shutdown(); return ret; } static void nfsd_shutdown(void) { /* * write_ports can create the server without actually starting * any threads--if we get shut down before any threads are * started, then nfsd_last_thread will be run before any of this * other initialization has been done. */ if (!nfsd_up) return; nfs4_state_shutdown(); lockd_down(); nfsd_racache_shutdown(); nfsd_up = false; } static void nfsd_last_thread(struct svc_serv *serv) { /* When last nfsd thread exits we need to do some clean-up */ nfsd_serv = NULL; nfsd_shutdown(); printk(KERN_WARNING "nfsd: last server has exited, flushing export " "cache\n"); nfsd_export_flush(); } void nfsd_reset_versions(void) { int found_one = 0; int i; for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) { if (nfsd_program.pg_vers[i]) found_one = 1; } if (!found_one) { for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) nfsd_program.pg_vers[i] = nfsd_version[i]; #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++) nfsd_acl_program.pg_vers[i] = nfsd_acl_version[i]; #endif } } /* * Each session guarantees a negotiated per slot memory cache for replies * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated * NFSv4.1 server might want to use more memory for a DRC than a machine * with mutiple services. * * Impose a hard limit on the number of pages for the DRC which varies * according to the machines free pages. This is of course only a default. * * For now this is a #defined shift which could be under admin control * in the future. */ static void set_max_drc(void) { #define NFSD_DRC_SIZE_SHIFT 10 nfsd_drc_max_mem = (nr_free_buffer_pages() >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE; nfsd_drc_mem_used = 0; spin_lock_init(&nfsd_drc_lock); dprintk("%s nfsd_drc_max_mem %u \n", __func__, nfsd_drc_max_mem); } int nfsd_create_serv(void) { int err = 0; WARN_ON(!mutex_is_locked(&nfsd_mutex)); if (nfsd_serv) { svc_get(nfsd_serv); return 0; } if (nfsd_max_blksize == 0) { /* choose a suitable default */ struct sysinfo i; si_meminfo(&i); /* Aim for 1/4096 of memory per thread * This gives 1MB on 4Gig machines * But only uses 32K on 128M machines. * Bottom out at 8K on 32M and smaller. * Of course, this is only a default. */ nfsd_max_blksize = NFSSVC_MAXBLKSIZE; i.totalram <<= PAGE_SHIFT - 12; while (nfsd_max_blksize > i.totalram && nfsd_max_blksize >= 8*1024*2) nfsd_max_blksize /= 2; } nfsd_reset_versions(); nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, nfsd_last_thread, nfsd, THIS_MODULE); if (nfsd_serv == NULL) return -ENOMEM; set_max_drc(); do_gettimeofday(&nfssvc_boot); /* record boot time */ return err; } int nfsd_nrpools(void) { if (nfsd_serv == NULL) return 0; else return nfsd_serv->sv_nrpools; } int nfsd_get_nrthreads(int n, int *nthreads) { int i = 0; if (nfsd_serv != NULL) { for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; } return 0; } int nfsd_set_nrthreads(int n, int *nthreads) { int i = 0; int tot = 0; int err = 0; WARN_ON(!mutex_is_locked(&nfsd_mutex)); if (nfsd_serv == NULL || n <= 0) return 0; if (n > nfsd_serv->sv_nrpools) n = nfsd_serv->sv_nrpools; /* enforce a global maximum number of threads */ tot = 0; for (i = 0; i < n; i++) { if (nthreads[i] > NFSD_MAXSERVS) nthreads[i] = NFSD_MAXSERVS; tot += nthreads[i]; } if (tot > NFSD_MAXSERVS) { /* total too large: scale down requested numbers */ for (i = 0; i < n && tot > 0; i++) { int new = nthreads[i] * NFSD_MAXSERVS / tot; tot -= (nthreads[i] - new); nthreads[i] = new; } for (i = 0; i < n && tot > 0; i++) { nthreads[i]--; tot--; } } /* * There must always be a thread in pool 0; the admin * can't shut down NFS completely using pool_threads. */ if (nthreads[0] == 0) nthreads[0] = 1; /* apply the new numbers */ svc_get(nfsd_serv); for (i = 0; i < n; i++) { err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], nthreads[i]); if (err) break; } svc_destroy(nfsd_serv); return err; } /* * Adjust the number of threads and return the new number of threads. * This is also the function that starts the server if necessary, if * this is the first time nrservs is nonzero. */ int nfsd_svc(unsigned short port, int nrservs) { int error; bool nfsd_up_before; mutex_lock(&nfsd_mutex); dprintk("nfsd: creating service\n"); if (nrservs <= 0) nrservs = 0; if (nrservs > NFSD_MAXSERVS) nrservs = NFSD_MAXSERVS; error = 0; if (nrservs == 0 && nfsd_serv == NULL) goto out; error = nfsd_create_serv(); if (error) goto out; nfsd_up_before = nfsd_up; error = nfsd_startup(port, nrservs); if (error) goto out_destroy; error = svc_set_num_threads(nfsd_serv, NULL, nrservs); if (error) goto out_shutdown; /* We are holding a reference to nfsd_serv which * we don't want to count in the return value, * so subtract 1 */ error = nfsd_serv->sv_nrthreads - 1; out_shutdown: if (error < 0 && !nfsd_up_before) nfsd_shutdown(); out_destroy: svc_destroy(nfsd_serv); /* Release server */ out: mutex_unlock(&nfsd_mutex); return error; } /* * This is the NFS server kernel thread */ static int nfsd(void *vrqstp) { struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp; int err, preverr = 0; /* Lock module and set up kernel thread */ mutex_lock(&nfsd_mutex); /* At this point, the thread shares current->fs * with the init process. We need to create files with a * umask of 0 instead of init's umask. */ if (unshare_fs_struct() < 0) { printk("Unable to start nfsd thread: out of memory\n"); goto out; } current->fs->umask = 0; /* * thread is spawned with all signals set to SIG_IGN, re-enable * the ones that will bring down the thread */ allow_signal(SIGKILL); allow_signal(SIGHUP); allow_signal(SIGINT); allow_signal(SIGQUIT); nfsdstats.th_cnt++; mutex_unlock(&nfsd_mutex); /* * We want less throttling in balance_dirty_pages() so that nfs to * localhost doesn't cause nfsd to lock up due to all the client's * dirty pages. */ current->flags |= PF_LESS_THROTTLE; set_freezable(); /* * The main request loop */ for (;;) { /* * Find a socket with data available and call its * recvfrom routine. */ while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN) ; if (err == -EINTR) break; else if (err < 0) { if (err != preverr) { printk(KERN_WARNING "%s: unexpected error " "from svc_recv (%d)\n", __func__, -err); preverr = err; } schedule_timeout_uninterruptible(HZ); continue; } /* Lock the export hash tables for reading. */ exp_readlock(); validate_process_creds(); svc_process(rqstp); validate_process_creds(); /* Unlock export hash tables */ exp_readunlock(); } /* Clear signals before calling svc_exit_thread() */ flush_signals(current); mutex_lock(&nfsd_mutex); nfsdstats.th_cnt --; out: /* Release the thread */ svc_exit_thread(rqstp); /* Release module */ mutex_unlock(&nfsd_mutex); module_put_and_exit(0); return 0; } static __be32 map_new_errors(u32 vers, __be32 nfserr) { if (nfserr == nfserr_jukebox && vers == 2) return nfserr_dropit; if (nfserr == nfserr_wrongsec && vers < 4) return nfserr_acces; return nfserr; } int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp) { struct svc_procedure *proc; kxdrproc_t xdr; __be32 nfserr; __be32 *nfserrp; dprintk("nfsd_dispatch: vers %d proc %d\n", rqstp->rq_vers, rqstp->rq_proc); proc = rqstp->rq_procinfo; /* Check whether we have this call in the cache. */ switch (nfsd_cache_lookup(rqstp, proc->pc_cachetype)) { case RC_INTR: case RC_DROPIT: return 0; case RC_REPLY: return 1; case RC_DOIT:; /* do it */ } /* Decode arguments */ xdr = proc->pc_decode; if (xdr && !xdr(rqstp, (__be32*)rqstp->rq_arg.head[0].iov_base, rqstp->rq_argp)) { dprintk("nfsd: failed to decode arguments!\n"); nfsd_cache_update(rqstp, RC_NOCACHE, NULL); *statp = rpc_garbage_args; return 1; } /* need to grab the location to store the status, as * nfsv4 does some encoding while processing */ nfserrp = rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len; rqstp->rq_res.head[0].iov_len += sizeof(__be32); /* Now call the procedure handler, and encode NFS status. */ nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp); nfserr = map_new_errors(rqstp->rq_vers, nfserr); if (nfserr == nfserr_dropit) { dprintk("nfsd: Dropping request; may be revisited later\n"); nfsd_cache_update(rqstp, RC_NOCACHE, NULL); return 0; } if (rqstp->rq_proc != 0) *nfserrp++ = nfserr; /* Encode result. * For NFSv2, additional info is never returned in case of an error. */ if (!(nfserr && rqstp->rq_vers == 2)) { xdr = proc->pc_encode; if (xdr && !xdr(rqstp, nfserrp, rqstp->rq_resp)) { /* Failed to encode result. Release cache entry */ dprintk("nfsd: failed to encode result!\n"); nfsd_cache_update(rqstp, RC_NOCACHE, NULL); *statp = rpc_system_err; return 1; } } /* Store reply in cache. */ nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1); return 1; } int nfsd_pool_stats_open(struct inode *inode, struct file *file) { int ret; mutex_lock(&nfsd_mutex); if (nfsd_serv == NULL) { mutex_unlock(&nfsd_mutex); return -ENODEV; } /* bump up the psudo refcount while traversing */ svc_get(nfsd_serv); ret = svc_pool_stats_open(nfsd_serv, file); mutex_unlock(&nfsd_mutex); return ret; } int nfsd_pool_stats_release(struct inode *inode, struct file *file) { int ret = seq_release(inode, file); mutex_lock(&nfsd_mutex); /* this function really, really should have been called svc_put() */ svc_destroy(nfsd_serv); mutex_unlock(&nfsd_mutex); return ret; }