Author: rmacklem
Date: Sat Dec 1 01:07:51 2012
New Revision: 243738
URL: http://svnweb.freebsd.org/changeset/base/243738
Log:
MFC: r241561
Add two new options to the nfssvc(2) syscall that allow
processes running as root to suspend/resume execution
of the kernel nfsd threads. An earlier version of this
patch was tested by Vincent Hoffman (vince at unsane.co.uk)
and John Hickey (jh at deterlab.net).
Modified:
stable/9/sys/fs/nfsserver/nfs_nfsdkrpc.c
stable/9/sys/fs/nfsserver/nfs_nfsdport.c
stable/9/sys/nfs/nfs_nfssvc.c
stable/9/sys/nfs/nfssvc.h
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/fs/ (props changed)
Modified: stable/9/sys/fs/nfsserver/nfs_nfsdkrpc.c
==============================================================================
--- stable/9/sys/fs/nfsserver/nfs_nfsdkrpc.c Sat Dec 1 00:56:19 2012
(r243737)
+++ stable/9/sys/fs/nfsserver/nfs_nfsdkrpc.c Sat Dec 1 01:07:51 2012
(r243738)
@@ -45,6 +45,8 @@ __FBSDID("$FreeBSD$");
#include <security/mac/mac_framework.h>
NFSDLOCKMUTEX;
+NFSV4ROOTLOCKMUTEX;
+struct nfsv4lock nfsd_suspend_lock;
/*
* Mapping of old NFS Version 2 RPC numbers to generic numbers.
@@ -221,9 +223,24 @@ nfssvc_program(struct svc_req *rqst, SVC
#ifdef MAC
mac_cred_associate_nfsd(nd.nd_cred);
#endif
+ /*
+ * Get a refcnt (shared lock) on nfsd_suspend_lock.
+ * NFSSVC_SUSPENDNFSD will take an exclusive lock on
+ * nfsd_suspend_lock to suspend these threads.
+ * This must be done here, before the check of
+ * nfsv4root exports by nfsvno_v4rootexport().
+ */
+ NFSLOCKV4ROOTMUTEX();
+ nfsv4_getref(&nfsd_suspend_lock, NULL, NFSV4ROOTLOCKMUTEXPTR,
+ NULL);
+ NFSUNLOCKV4ROOTMUTEX();
+
if ((nd.nd_flag & ND_NFSV4) != 0) {
nd.nd_repstat = nfsvno_v4rootexport(&nd);
if (nd.nd_repstat != 0) {
+ NFSLOCKV4ROOTMUTEX();
+ nfsv4_relref(&nfsd_suspend_lock);
+ NFSUNLOCKV4ROOTMUTEX();
svcerr_weakauth(rqst);
svc_freereq(rqst);
m_freem(nd.nd_mrep);
@@ -233,6 +250,9 @@ nfssvc_program(struct svc_req *rqst, SVC
cacherep = nfs_proc(&nd, rqst->rq_xid, xprt->xp_socket,
xprt->xp_sockref, &rp);
+ NFSLOCKV4ROOTMUTEX();
+ nfsv4_relref(&nfsd_suspend_lock);
+ NFSUNLOCKV4ROOTMUTEX();
} else {
NFSMGET(nd.nd_mreq);
nd.nd_mreq->m_len = 0;
Modified: stable/9/sys/fs/nfsserver/nfs_nfsdport.c
==============================================================================
--- stable/9/sys/fs/nfsserver/nfs_nfsdport.c Sat Dec 1 00:56:19 2012
(r243737)
+++ stable/9/sys/fs/nfsserver/nfs_nfsdport.c Sat Dec 1 01:07:51 2012
(r243738)
@@ -57,6 +57,7 @@ extern struct mount nfsv4root_mnt;
extern struct nfsrv_stablefirst nfsrv_stablefirst;
extern void (*nfsd_call_servertimer)(void);
extern SVCPOOL *nfsrvd_pool;
+extern struct nfsv4lock nfsd_suspend_lock;
struct vfsoptlist nfsv4root_opt, nfsv4root_newopt;
NFSDLOCKMUTEX;
struct mtx nfs_cache_mutex;
@@ -3104,8 +3105,9 @@ nfssvc_srvcall(struct thread *p, struct
struct nfsd_dumplocks *dumplocks;
struct nameidata nd;
vnode_t vp;
- int error = EINVAL;
+ int error = EINVAL, igotlock;
struct proc *procp;
+ static int suspend_nfsd = 0;
if (uap->flag & NFSSVC_PUBLICFH) {
NFSBZERO((caddr_t)&nfs_pubfh.nfsrvfh_data,
@@ -3184,6 +3186,26 @@ nfssvc_srvcall(struct thread *p, struct
nfsd_master_start = procp->p_stats->p_start;
nfsd_master_proc = procp;
PROC_UNLOCK(procp);
+ } else if ((uap->flag & NFSSVC_SUSPENDNFSD) != 0) {
+ NFSLOCKV4ROOTMUTEX();
+ if (suspend_nfsd == 0) {
+ /* Lock out all nfsd threads */
+ do {
+ igotlock = nfsv4_lock(&nfsd_suspend_lock, 1,
+ NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
+ } while (igotlock == 0 && suspend_nfsd == 0);
+ suspend_nfsd = 1;
+ }
+ NFSUNLOCKV4ROOTMUTEX();
+ error = 0;
+ } else if ((uap->flag & NFSSVC_RESUMENFSD) != 0) {
+ NFSLOCKV4ROOTMUTEX();
+ if (suspend_nfsd != 0) {
+ nfsv4_unlock(&nfsd_suspend_lock, 0);
+ suspend_nfsd = 0;
+ }
+ NFSUNLOCKV4ROOTMUTEX();
+ error = 0;
}
NFSEXITCODE(error);
Modified: stable/9/sys/nfs/nfs_nfssvc.c
==============================================================================
--- stable/9/sys/nfs/nfs_nfssvc.c Sat Dec 1 00:56:19 2012
(r243737)
+++ stable/9/sys/nfs/nfs_nfssvc.c Sat Dec 1 01:07:51 2012
(r243738)
@@ -102,7 +102,8 @@ sys_nfssvc(struct thread *td, struct nfs
else if ((uap->flag & (NFSSVC_NFSDNFSD | NFSSVC_NFSDADDSOCK |
NFSSVC_PUBLICFH | NFSSVC_V4ROOTEXPORT | NFSSVC_NOPUBLICFH |
NFSSVC_STABLERESTART | NFSSVC_ADMINREVOKE |
- NFSSVC_DUMPCLIENTS | NFSSVC_DUMPLOCKS | NFSSVC_BACKUPSTABLE)) &&
+ NFSSVC_DUMPCLIENTS | NFSSVC_DUMPLOCKS | NFSSVC_BACKUPSTABLE |
+ NFSSVC_SUSPENDNFSD | NFSSVC_RESUMENFSD)) &&
nfsd_call_nfsd != NULL)
error = (*nfsd_call_nfsd)(td, uap);
if (error == EINTR || error == ERESTART)
Modified: stable/9/sys/nfs/nfssvc.h
==============================================================================
--- stable/9/sys/nfs/nfssvc.h Sat Dec 1 00:56:19 2012 (r243737)
+++ stable/9/sys/nfs/nfssvc.h Sat Dec 1 01:07:51 2012 (r243738)
@@ -66,5 +66,7 @@
#define NFSSVC_BACKUPSTABLE 0x00800000
#define NFSSVC_ZEROCLTSTATS 0x01000000 /* modifier for
GETSTATS */
#define NFSSVC_ZEROSRVSTATS 0x02000000 /* modifier for
GETSTATS */
+#define NFSSVC_SUSPENDNFSD 0x04000000
+#define NFSSVC_RESUMENFSD 0x08000000
#endif /* _NFS_NFSSVC_H */
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