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Message-ID: <20120524101449.11252.82184.stgit@localhost.localdomain>
Date: Thu, 24 May 2012 14:15:39 +0400
From: Stanislav Kinsbursky <skinsbursky@...allels.com>
To: bfields@...ldses.org
Cc: linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org,
devel@...nvz.org
Subject: [PATCH v2] NFSd: set nfsd_serv to NULL after service destruction
v2:
1) Set global nfsd_serv pointer to NULL only if no running threads left.
Otherwise we will get NULL pointer dereference.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@...allels.com>
---
fs/nfsd/nfsctl.c | 8 ++------
fs/nfsd/nfsd.h | 11 +++++++++++
fs/nfsd/nfssvc.c | 24 ++++++++----------------
3 files changed, 21 insertions(+), 22 deletions(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c55298e..fa49cff 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -673,9 +673,7 @@ static ssize_t __write_ports_addfd(char *buf)
err = svc_addsock(nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);
if (err < 0) {
- if (nfsd_serv->sv_nrthreads == 1)
- svc_shutdown_net(nfsd_serv, net);
- svc_destroy(nfsd_serv);
+ nfsd_destroy(net);
return err;
}
@@ -744,9 +742,7 @@ out_close:
svc_xprt_put(xprt);
}
out_err:
- if (nfsd_serv->sv_nrthreads == 1)
- svc_shutdown_net(nfsd_serv, net);
- svc_destroy(nfsd_serv);
+ nfsd_destroy(net);
return err;
}
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 1671429..1336a65 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -73,6 +73,17 @@ int nfsd_nrpools(void);
int nfsd_get_nrthreads(int n, int *);
int nfsd_set_nrthreads(int n, int *);
+static inline void nfsd_destroy(struct net *net)
+{
+ int destroy = (nfsd_serv->sv_nrthreads == 1);
+
+ if (destroy)
+ svc_shutdown_net(nfsd_serv, net);
+ svc_destroy(nfsd_serv);
+ if (destroy)
+ nfsd_serv = NULL;
+}
+
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
#ifdef CONFIG_NFSD_V2_ACL
extern struct svc_version nfsd_acl_version2;
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index ee709fc..240473c 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -254,8 +254,6 @@ static void nfsd_shutdown(void)
static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
{
- /* When last nfsd thread exits we need to do some clean-up */
- nfsd_serv = NULL;
nfsd_shutdown();
svc_rpcb_cleanup(serv, net);
@@ -332,6 +330,7 @@ static int nfsd_get_default_max_blksize(void)
int nfsd_create_serv(void)
{
int error;
+ struct net *net = current->nsproxy->net_ns;
WARN_ON(!mutex_is_locked(&nfsd_mutex));
if (nfsd_serv) {
@@ -346,7 +345,7 @@ int nfsd_create_serv(void)
if (nfsd_serv == NULL)
return -ENOMEM;
- error = svc_bind(nfsd_serv, current->nsproxy->net_ns);
+ error = svc_bind(nfsd_serv, net);
if (error < 0) {
svc_destroy(nfsd_serv);
return error;
@@ -427,11 +426,7 @@ int nfsd_set_nrthreads(int n, int *nthreads)
if (err)
break;
}
-
- if (nfsd_serv->sv_nrthreads == 1)
- svc_shutdown_net(nfsd_serv, net);
- svc_destroy(nfsd_serv);
-
+ nfsd_destroy(net);
return err;
}
@@ -478,9 +473,7 @@ out_shutdown:
if (error < 0 && !nfsd_up_before)
nfsd_shutdown();
out_destroy:
- if (nfsd_serv->sv_nrthreads == 1)
- svc_shutdown_net(nfsd_serv, net);
- svc_destroy(nfsd_serv); /* Release server */
+ nfsd_destroy(net); /* Release server */
out:
mutex_unlock(&nfsd_mutex);
return error;
@@ -563,12 +556,13 @@ nfsd(void *vrqstp)
nfsdstats.th_cnt --;
out:
- if (rqstp->rq_server->sv_nrthreads == 1)
- svc_shutdown_net(rqstp->rq_server, &init_net);
+ rqstp->rq_server = NULL;
/* Release the thread */
svc_exit_thread(rqstp);
+ nfsd_destroy(&init_net);
+
/* Release module */
mutex_unlock(&nfsd_mutex);
module_put_and_exit(0);
@@ -682,9 +676,7 @@ int nfsd_pool_stats_release(struct inode *inode, struct file *file)
mutex_lock(&nfsd_mutex);
/* this function really, really should have been called svc_put() */
- if (nfsd_serv->sv_nrthreads == 1)
- svc_shutdown_net(nfsd_serv, net);
- svc_destroy(nfsd_serv);
+ nfsd_destroy(net);
mutex_unlock(&nfsd_mutex);
return ret;
}
--
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