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Diffstat (limited to 'fs/nfsd/nfssvc.c')
-rw-r--r--fs/nfsd/nfssvc.c148
1 files changed, 76 insertions, 72 deletions
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 941041f4b136..80292ff5e924 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -21,6 +21,7 @@
#include <linux/smp_lock.h>
#include <linux/freezer.h>
#include <linux/fs_struct.h>
+#include <linux/kthread.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/stats.h>
@@ -36,28 +37,38 @@
#define NFSDDBG_FACILITY NFSDDBG_SVC
-/* these signals will be delivered to an nfsd thread
- * when handling a request
- */
-#define ALLOWED_SIGS (sigmask(SIGKILL))
-/* these signals will be delivered to an nfsd thread
- * when not handling a request. i.e. when waiting
- */
-#define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
-/* if the last thread dies with SIGHUP, then the exports table is
- * left unchanged ( like 2.4-{0-9} ). Any other signal will clear
- * the exports table (like 2.2).
- */
-#define SIG_NOCLEAN SIGHUP
-
extern struct svc_program nfsd_program;
-static void nfsd(struct svc_rqst *rqstp);
+static int nfsd(void *vrqstp);
struct timeval nfssvc_boot;
- struct svc_serv *nfsd_serv;
static atomic_t nfsd_busy;
static unsigned long nfsd_last_call;
static DEFINE_SPINLOCK(nfsd_call_lock);
+/*
+ * 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;
+
#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[] = {
@@ -145,13 +156,14 @@ int nfsd_vers(int vers, enum vers_op change)
int nfsd_nrthreads(void)
{
- if (nfsd_serv == NULL)
- return 0;
- else
- return nfsd_serv->sv_nrthreads;
+ int rv = 0;
+ mutex_lock(&nfsd_mutex);
+ if (nfsd_serv)
+ rv = nfsd_serv->sv_nrthreads;
+ mutex_unlock(&nfsd_mutex);
+ return rv;
}
-static int killsig; /* signal that was used to kill last nfsd */
static void nfsd_last_thread(struct svc_serv *serv)
{
/* When last nfsd thread exits we need to do some clean-up */
@@ -162,11 +174,9 @@ static void nfsd_last_thread(struct svc_serv *serv)
nfsd_racache_shutdown();
nfs4_state_shutdown();
- printk(KERN_WARNING "nfsd: last server has exited\n");
- if (killsig != SIG_NOCLEAN) {
- printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
- nfsd_export_flush();
- }
+ printk(KERN_WARNING "nfsd: last server has exited, flushing export "
+ "cache\n");
+ nfsd_export_flush();
}
void nfsd_reset_versions(void)
@@ -190,13 +200,14 @@ void nfsd_reset_versions(void)
}
}
+
int nfsd_create_serv(void)
{
int err = 0;
- lock_kernel();
+
+ WARN_ON(!mutex_is_locked(&nfsd_mutex));
if (nfsd_serv) {
svc_get(nfsd_serv);
- unlock_kernel();
return 0;
}
if (nfsd_max_blksize == 0) {
@@ -217,13 +228,11 @@ int nfsd_create_serv(void)
}
atomic_set(&nfsd_busy, 0);
- nfsd_serv = svc_create_pooled(&nfsd_program,
- nfsd_max_blksize,
- nfsd_last_thread,
- nfsd, SIG_NOCLEAN, THIS_MODULE);
+ nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
+ nfsd_last_thread, nfsd, THIS_MODULE);
if (nfsd_serv == NULL)
err = -ENOMEM;
- unlock_kernel();
+
do_gettimeofday(&nfssvc_boot); /* record boot time */
return err;
}
@@ -282,6 +291,8 @@ int nfsd_set_nrthreads(int n, int *nthreads)
int tot = 0;
int err = 0;
+ WARN_ON(!mutex_is_locked(&nfsd_mutex));
+
if (nfsd_serv == NULL || n <= 0)
return 0;
@@ -316,7 +327,6 @@ int nfsd_set_nrthreads(int n, int *nthreads)
nthreads[0] = 1;
/* apply the new numbers */
- lock_kernel();
svc_get(nfsd_serv);
for (i = 0; i < n; i++) {
err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i],
@@ -325,7 +335,6 @@ int nfsd_set_nrthreads(int n, int *nthreads)
break;
}
svc_destroy(nfsd_serv);
- unlock_kernel();
return err;
}
@@ -334,8 +343,8 @@ int
nfsd_svc(unsigned short port, int nrservs)
{
int error;
-
- lock_kernel();
+
+ mutex_lock(&nfsd_mutex);
dprintk("nfsd: creating service\n");
error = -EINVAL;
if (nrservs <= 0)
@@ -363,7 +372,7 @@ nfsd_svc(unsigned short port, int nrservs)
failure:
svc_destroy(nfsd_serv); /* Release server */
out:
- unlock_kernel();
+ mutex_unlock(&nfsd_mutex);
return error;
}
@@ -391,18 +400,17 @@ update_thread_usage(int busy_threads)
/*
* This is the NFS server kernel thread
*/
-static void
-nfsd(struct svc_rqst *rqstp)
+static int
+nfsd(void *vrqstp)
{
+ struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
struct fs_struct *fsp;
- int err;
- sigset_t shutdown_mask, allowed_mask;
+ int err, preverr = 0;
/* Lock module and set up kernel thread */
- lock_kernel();
- daemonize("nfsd");
+ mutex_lock(&nfsd_mutex);
- /* After daemonize() this kernel thread shares current->fs
+ /* 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. */
fsp = copy_fs_struct(current->fs);
@@ -414,14 +422,17 @@ nfsd(struct svc_rqst *rqstp)
current->fs = fsp;
current->fs->umask = 0;
- siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
- siginitsetinv(&allowed_mask, ALLOWED_SIGS);
+ /*
+ * 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++;
-
- rqstp->rq_task = current;
-
- unlock_kernel();
+ mutex_unlock(&nfsd_mutex);
/*
* We want less throttling in balance_dirty_pages() so that nfs to
@@ -435,26 +446,30 @@ nfsd(struct svc_rqst *rqstp)
* The main request loop
*/
for (;;) {
- /* Block all but the shutdown signals */
- sigprocmask(SIG_SETMASK, &shutdown_mask, NULL);
-
/*
* Find a socket with data available and call its
* recvfrom routine.
*/
while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
;
- if (err < 0)
+ 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;
+ }
+
update_thread_usage(atomic_read(&nfsd_busy));
atomic_inc(&nfsd_busy);
/* Lock the export hash tables for reading. */
exp_readlock();
- /* Process request with signals blocked. */
- sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
-
svc_process(rqstp);
/* Unlock export hash tables */
@@ -463,22 +478,10 @@ nfsd(struct svc_rqst *rqstp)
atomic_dec(&nfsd_busy);
}
- if (err != -EINTR) {
- printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
- } else {
- unsigned int signo;
-
- for (signo = 1; signo <= _NSIG; signo++)
- if (sigismember(&current->pending.signal, signo) &&
- !sigismember(&current->blocked, signo))
- break;
- killsig = signo;
- }
/* Clear signals before calling svc_exit_thread() */
flush_signals(current);
- lock_kernel();
-
+ mutex_lock(&nfsd_mutex);
nfsdstats.th_cnt --;
out:
@@ -486,8 +489,9 @@ out:
svc_exit_thread(rqstp);
/* Release module */
- unlock_kernel();
+ mutex_unlock(&nfsd_mutex);
module_put_and_exit(0);
+ return 0;
}
static __be32 map_new_errors(u32 vers, __be32 nfserr)
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-05-01 02:30:48 +0000