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100766f834
knfsd currently uses 2 signal masks when processing requests. A "loose" mask (SHUTDOWN_SIGS) that it uses when receiving network requests, and then a more "strict" mask (ALLOWED_SIGS, which is just SIGKILL) that it allows when doing the actual operation on the local storage. This is apparently unnecessarily complicated. The underlying filesystem should be able to sanely handle a signal in the middle of an operation. This patch removes the signal mask handling from knfsd altogether. When knfsd is started as a kthread, all signals are ignored. It then allows all of the signals in SHUTDOWN_SIGS. There's no need to set the mask as well. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
577 lines
13 KiB
C
577 lines
13 KiB
C
/*
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* linux/fs/nfsd/nfssvc.c
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*
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* Central processing for nfsd.
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*
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* Authors: Olaf Kirch (okir@monad.swb.de)
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*
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* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/time.h>
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#include <linux/errno.h>
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#include <linux/nfs.h>
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#include <linux/in.h>
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#include <linux/uio.h>
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#include <linux/unistd.h>
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#include <linux/slab.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/freezer.h>
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#include <linux/fs_struct.h>
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#include <linux/kthread.h>
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#include <linux/sunrpc/types.h>
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#include <linux/sunrpc/stats.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/sunrpc/svcsock.h>
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#include <linux/sunrpc/cache.h>
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#include <linux/nfsd/nfsd.h>
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#include <linux/nfsd/stats.h>
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#include <linux/nfsd/cache.h>
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#include <linux/nfsd/syscall.h>
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#include <linux/lockd/bind.h>
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#include <linux/nfsacl.h>
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#define NFSDDBG_FACILITY NFSDDBG_SVC
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extern struct svc_program nfsd_program;
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static int nfsd(void *vrqstp);
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struct timeval nfssvc_boot;
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static atomic_t nfsd_busy;
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static unsigned long nfsd_last_call;
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static DEFINE_SPINLOCK(nfsd_call_lock);
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/*
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* nfsd_mutex protects nfsd_serv -- both the pointer itself and the members
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* of the svc_serv struct. In particular, ->sv_nrthreads but also to some
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* extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt
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*
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* If (out side the lock) nfsd_serv is non-NULL, then it must point to a
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* properly initialised 'struct svc_serv' with ->sv_nrthreads > 0. That number
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* of nfsd threads must exist and each must listed in ->sp_all_threads in each
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* entry of ->sv_pools[].
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*
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* Transitions of the thread count between zero and non-zero are of particular
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* interest since the svc_serv needs to be created and initialized at that
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* point, or freed.
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*
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* Finally, the nfsd_mutex also protects some of the global variables that are
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* accessed when nfsd starts and that are settable via the write_* routines in
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* nfsctl.c. In particular:
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*
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* user_recovery_dirname
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* user_lease_time
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* nfsd_versions
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*/
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DEFINE_MUTEX(nfsd_mutex);
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struct svc_serv *nfsd_serv;
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#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
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static struct svc_stat nfsd_acl_svcstats;
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static struct svc_version * nfsd_acl_version[] = {
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[2] = &nfsd_acl_version2,
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[3] = &nfsd_acl_version3,
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};
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#define NFSD_ACL_MINVERS 2
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#define NFSD_ACL_NRVERS ARRAY_SIZE(nfsd_acl_version)
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static struct svc_version *nfsd_acl_versions[NFSD_ACL_NRVERS];
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static struct svc_program nfsd_acl_program = {
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.pg_prog = NFS_ACL_PROGRAM,
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.pg_nvers = NFSD_ACL_NRVERS,
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.pg_vers = nfsd_acl_versions,
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.pg_name = "nfsacl",
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.pg_class = "nfsd",
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.pg_stats = &nfsd_acl_svcstats,
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.pg_authenticate = &svc_set_client,
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};
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static struct svc_stat nfsd_acl_svcstats = {
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.program = &nfsd_acl_program,
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};
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#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */
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static struct svc_version * nfsd_version[] = {
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[2] = &nfsd_version2,
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#if defined(CONFIG_NFSD_V3)
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[3] = &nfsd_version3,
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#endif
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#if defined(CONFIG_NFSD_V4)
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[4] = &nfsd_version4,
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#endif
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};
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#define NFSD_MINVERS 2
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#define NFSD_NRVERS ARRAY_SIZE(nfsd_version)
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static struct svc_version *nfsd_versions[NFSD_NRVERS];
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struct svc_program nfsd_program = {
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#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
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.pg_next = &nfsd_acl_program,
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#endif
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.pg_prog = NFS_PROGRAM, /* program number */
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.pg_nvers = NFSD_NRVERS, /* nr of entries in nfsd_version */
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.pg_vers = nfsd_versions, /* version table */
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.pg_name = "nfsd", /* program name */
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.pg_class = "nfsd", /* authentication class */
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.pg_stats = &nfsd_svcstats, /* version table */
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.pg_authenticate = &svc_set_client, /* export authentication */
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};
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int nfsd_vers(int vers, enum vers_op change)
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{
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if (vers < NFSD_MINVERS || vers >= NFSD_NRVERS)
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return -1;
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switch(change) {
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case NFSD_SET:
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nfsd_versions[vers] = nfsd_version[vers];
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#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
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if (vers < NFSD_ACL_NRVERS)
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nfsd_acl_versions[vers] = nfsd_acl_version[vers];
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#endif
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break;
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case NFSD_CLEAR:
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nfsd_versions[vers] = NULL;
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#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
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if (vers < NFSD_ACL_NRVERS)
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nfsd_acl_versions[vers] = NULL;
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#endif
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break;
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case NFSD_TEST:
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return nfsd_versions[vers] != NULL;
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case NFSD_AVAIL:
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return nfsd_version[vers] != NULL;
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}
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return 0;
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}
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/*
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* Maximum number of nfsd processes
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*/
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#define NFSD_MAXSERVS 8192
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int nfsd_nrthreads(void)
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{
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int rv = 0;
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mutex_lock(&nfsd_mutex);
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if (nfsd_serv)
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rv = nfsd_serv->sv_nrthreads;
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mutex_unlock(&nfsd_mutex);
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return rv;
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}
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static void nfsd_last_thread(struct svc_serv *serv)
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{
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/* When last nfsd thread exits we need to do some clean-up */
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struct svc_xprt *xprt;
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list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list)
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lockd_down();
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nfsd_serv = NULL;
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nfsd_racache_shutdown();
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nfs4_state_shutdown();
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printk(KERN_WARNING "nfsd: last server has exited, flushing export "
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"cache\n");
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nfsd_export_flush();
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}
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void nfsd_reset_versions(void)
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{
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int found_one = 0;
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int i;
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for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
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if (nfsd_program.pg_vers[i])
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found_one = 1;
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}
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if (!found_one) {
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for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
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nfsd_program.pg_vers[i] = nfsd_version[i];
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#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
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for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
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nfsd_acl_program.pg_vers[i] =
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nfsd_acl_version[i];
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#endif
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}
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}
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int nfsd_create_serv(void)
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{
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int err = 0;
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WARN_ON(!mutex_is_locked(&nfsd_mutex));
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if (nfsd_serv) {
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svc_get(nfsd_serv);
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return 0;
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}
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if (nfsd_max_blksize == 0) {
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/* choose a suitable default */
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struct sysinfo i;
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si_meminfo(&i);
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/* Aim for 1/4096 of memory per thread
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* This gives 1MB on 4Gig machines
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* But only uses 32K on 128M machines.
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* Bottom out at 8K on 32M and smaller.
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* Of course, this is only a default.
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*/
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nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
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i.totalram <<= PAGE_SHIFT - 12;
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while (nfsd_max_blksize > i.totalram &&
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nfsd_max_blksize >= 8*1024*2)
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nfsd_max_blksize /= 2;
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}
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atomic_set(&nfsd_busy, 0);
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nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
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nfsd_last_thread, nfsd, THIS_MODULE);
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if (nfsd_serv == NULL)
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err = -ENOMEM;
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do_gettimeofday(&nfssvc_boot); /* record boot time */
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return err;
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}
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static int nfsd_init_socks(int port)
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{
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int error;
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if (!list_empty(&nfsd_serv->sv_permsocks))
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return 0;
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error = lockd_up(IPPROTO_UDP);
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if (error >= 0) {
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error = svc_create_xprt(nfsd_serv, "udp", port,
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SVC_SOCK_DEFAULTS);
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if (error < 0)
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lockd_down();
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}
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if (error < 0)
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return error;
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error = lockd_up(IPPROTO_TCP);
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if (error >= 0) {
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error = svc_create_xprt(nfsd_serv, "tcp", port,
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SVC_SOCK_DEFAULTS);
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if (error < 0)
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lockd_down();
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}
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if (error < 0)
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return error;
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return 0;
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}
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int nfsd_nrpools(void)
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{
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if (nfsd_serv == NULL)
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return 0;
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else
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return nfsd_serv->sv_nrpools;
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}
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int nfsd_get_nrthreads(int n, int *nthreads)
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{
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int i = 0;
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if (nfsd_serv != NULL) {
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for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++)
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nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads;
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}
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return 0;
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}
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int nfsd_set_nrthreads(int n, int *nthreads)
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{
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int i = 0;
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int tot = 0;
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int err = 0;
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WARN_ON(!mutex_is_locked(&nfsd_mutex));
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if (nfsd_serv == NULL || n <= 0)
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return 0;
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if (n > nfsd_serv->sv_nrpools)
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n = nfsd_serv->sv_nrpools;
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/* enforce a global maximum number of threads */
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tot = 0;
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for (i = 0; i < n; i++) {
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if (nthreads[i] > NFSD_MAXSERVS)
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nthreads[i] = NFSD_MAXSERVS;
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tot += nthreads[i];
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}
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if (tot > NFSD_MAXSERVS) {
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/* total too large: scale down requested numbers */
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for (i = 0; i < n && tot > 0; i++) {
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int new = nthreads[i] * NFSD_MAXSERVS / tot;
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tot -= (nthreads[i] - new);
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nthreads[i] = new;
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}
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for (i = 0; i < n && tot > 0; i++) {
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nthreads[i]--;
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tot--;
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}
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}
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/*
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* There must always be a thread in pool 0; the admin
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* can't shut down NFS completely using pool_threads.
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*/
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if (nthreads[0] == 0)
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nthreads[0] = 1;
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/* apply the new numbers */
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svc_get(nfsd_serv);
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for (i = 0; i < n; i++) {
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err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
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nthreads[i]);
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if (err)
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break;
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}
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svc_destroy(nfsd_serv);
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return err;
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}
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int
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nfsd_svc(unsigned short port, int nrservs)
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{
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int error;
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mutex_lock(&nfsd_mutex);
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dprintk("nfsd: creating service\n");
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error = -EINVAL;
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if (nrservs <= 0)
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nrservs = 0;
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if (nrservs > NFSD_MAXSERVS)
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nrservs = NFSD_MAXSERVS;
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/* Readahead param cache - will no-op if it already exists */
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error = nfsd_racache_init(2*nrservs);
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if (error<0)
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goto out;
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nfs4_state_start();
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nfsd_reset_versions();
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error = nfsd_create_serv();
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if (error)
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goto out;
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error = nfsd_init_socks(port);
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if (error)
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goto failure;
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error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
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failure:
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svc_destroy(nfsd_serv); /* Release server */
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out:
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mutex_unlock(&nfsd_mutex);
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return error;
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}
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static inline void
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update_thread_usage(int busy_threads)
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{
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unsigned long prev_call;
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unsigned long diff;
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int decile;
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spin_lock(&nfsd_call_lock);
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prev_call = nfsd_last_call;
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nfsd_last_call = jiffies;
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decile = busy_threads*10/nfsdstats.th_cnt;
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if (decile>0 && decile <= 10) {
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diff = nfsd_last_call - prev_call;
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if ( (nfsdstats.th_usage[decile-1] += diff) >= NFSD_USAGE_WRAP)
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nfsdstats.th_usage[decile-1] -= NFSD_USAGE_WRAP;
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if (decile == 10)
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nfsdstats.th_fullcnt++;
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}
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spin_unlock(&nfsd_call_lock);
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}
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/*
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* This is the NFS server kernel thread
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*/
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static int
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nfsd(void *vrqstp)
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{
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struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
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struct fs_struct *fsp;
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int err, preverr = 0;
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/* Lock module and set up kernel thread */
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mutex_lock(&nfsd_mutex);
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/* At this point, the thread shares current->fs
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* with the init process. We need to create files with a
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* umask of 0 instead of init's umask. */
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fsp = copy_fs_struct(current->fs);
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if (!fsp) {
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printk("Unable to start nfsd thread: out of memory\n");
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goto out;
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}
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exit_fs(current);
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current->fs = fsp;
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current->fs->umask = 0;
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/*
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* thread is spawned with all signals set to SIG_IGN, re-enable
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* the ones that will bring down the thread
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*/
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allow_signal(SIGKILL);
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allow_signal(SIGHUP);
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allow_signal(SIGINT);
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allow_signal(SIGQUIT);
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nfsdstats.th_cnt++;
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mutex_unlock(&nfsd_mutex);
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/*
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* We want less throttling in balance_dirty_pages() so that nfs to
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* localhost doesn't cause nfsd to lock up due to all the client's
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* dirty pages.
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*/
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current->flags |= PF_LESS_THROTTLE;
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set_freezable();
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/*
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* The main request loop
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*/
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for (;;) {
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/*
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* Find a socket with data available and call its
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* recvfrom routine.
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*/
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while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
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;
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if (err == -EINTR)
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break;
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else if (err < 0) {
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if (err != preverr) {
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printk(KERN_WARNING "%s: unexpected error "
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"from svc_recv (%d)\n", __func__, -err);
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preverr = err;
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}
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schedule_timeout_uninterruptible(HZ);
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continue;
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}
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update_thread_usage(atomic_read(&nfsd_busy));
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atomic_inc(&nfsd_busy);
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/* Lock the export hash tables for reading. */
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exp_readlock();
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svc_process(rqstp);
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/* Unlock export hash tables */
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exp_readunlock();
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update_thread_usage(atomic_read(&nfsd_busy));
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atomic_dec(&nfsd_busy);
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}
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/* Clear signals before calling svc_exit_thread() */
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flush_signals(current);
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mutex_lock(&nfsd_mutex);
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nfsdstats.th_cnt --;
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out:
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/* Release the thread */
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svc_exit_thread(rqstp);
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/* Release module */
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mutex_unlock(&nfsd_mutex);
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module_put_and_exit(0);
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return 0;
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|
}
|
|
|
|
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;
|
|
}
|