fix a problem with XID re-use when a server returns NFSERR_JUKEBOX.

Submitted by:	cel@citi.umich.edu
Fixed by:	rick@snowhite.cis.uoguelph.ca
Approved by:	alfred
MFC after:	3 weeks

3 files changed, 13 insertions, 7 deletions

diff --git a/sys/nfsclient/nfs_socket.c b/sys/nfsclient/nfs_socket.c
index 9e7a386..511e229 100644
--- a/sys/nfsclient/nfs_socket.c
+++ b/sys/nfsclient/nfs_socket.c
@@ -77,6 +77,8 @@ __FBSDID("$FreeBSD$");
 #define	TRUE	1
 #define	FALSE	0
 
+extern u_int32_t nfs_xid;
+
 /*
  * Estimate rto for an nfs rpc sent via. an unreliable datagram.
  * Use the mean and mean deviation of rtt for the appropriate type of rpc
@@ -924,7 +926,7 @@ nfs_request(struct vnode *vp, struct mbuf *mrest, int procnum,
 	int s, error = 0, mrest_len, auth_len, auth_type;
 	int trylater_delay = NQ_TRYLATERDEL, trylater_cnt = 0;
 	struct timeval now;
-	u_int32_t xid;
+	u_int32_t *xidp;
 
 	/* Reject requests while attempting a forced unmount. */
 	if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) {
@@ -956,7 +958,7 @@ nfs_request(struct vnode *vp, struct mbuf *mrest, int procnum,
 		nmp->nm_numgrps : (cred->cr_ngroups - 1)) << 2) +
 		5 * NFSX_UNSIGNED;
 	m = nfsm_rpchead(cred, nmp->nm_flag, procnum, auth_type, auth_len,
-	     mrest, mrest_len, &mheadend, &xid);
+	     mrest, mrest_len, &mheadend, &xidp);
 
 	/*
 	 * For stream protocols, insert a Sun RPC Record Mark.
@@ -967,7 +969,7 @@ nfs_request(struct vnode *vp, struct mbuf *mrest, int procnum,
 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
 	}
 	rep->r_mreq = m;
-	rep->r_xid = xid;
+	rep->r_xid = *xidp;
 tryagain:
 	if (nmp->nm_flag & NFSMNT_SOFT)
 		rep->r_retry = nmp->nm_retry;
@@ -1128,6 +1130,9 @@ tryagain:
 				trylater_delay *= nfs_backoff[trylater_cnt];
 				if (trylater_cnt < NFS_NBACKOFF - 1)
 					trylater_cnt++;
+				if (++nfs_xid == 0)
+					nfs_xid++;
+				rep->r_xid = *xidp = txdr_unsigned(nfs_xid);
 				goto tryagain;
 			}
 
diff --git a/sys/nfsclient/nfs_subs.c b/sys/nfsclient/nfs_subs.c
index 444c47b..fb67091 100644
--- a/sys/nfsclient/nfs_subs.c
+++ b/sys/nfsclient/nfs_subs.c
@@ -85,7 +85,7 @@ u_int32_t	rpc_call, rpc_vers, rpc_reply, rpc_msgdenied, rpc_autherr,
 u_int32_t	nfs_true, nfs_false;
 
 /* And other global data */
-static u_int32_t nfs_xid = 0;
+u_int32_t nfs_xid = 0;
 static enum vtype nv2tov_type[8]= {
 	VNON, VREG, VDIR, VBLK, VCHR, VLNK, VNON,  VNON
 };
@@ -155,7 +155,7 @@ nfsm_reqhead(struct vnode *vp, u_long procid, int hsiz)
 struct mbuf *
 nfsm_rpchead(struct ucred *cr, int nmflag, int procid, int auth_type,
     int auth_len, struct mbuf *mrest, int mrest_len, struct mbuf **mbp,
-    u_int32_t *xidp)
+    u_int32_t **xidpp)
 {
 	struct mbuf *mb;
 	u_int32_t *tl;
@@ -191,7 +191,8 @@ nfsm_rpchead(struct ucred *cr, int nmflag, int procid, int auth_type,
 	if (++nfs_xid == 0)
 		nfs_xid++;
 
-	*tl++ = *xidp = txdr_unsigned(nfs_xid);
+	*xidpp = tl;
+	*tl++ = txdr_unsigned(nfs_xid);
 	*tl++ = rpc_call;
 	*tl++ = rpc_vers;
 	*tl++ = txdr_unsigned(NFS_PROG);
diff --git a/sys/nfsclient/nfsm_subs.h b/sys/nfsclient/nfsm_subs.h
index 8083a47..62666a5 100644
--- a/sys/nfsclient/nfsm_subs.h
+++ b/sys/nfsclient/nfsm_subs.h
@@ -56,7 +56,7 @@ struct mbuf *nfsm_reqhead(struct vnode *vp, u_long procid, int hsiz);
 struct mbuf *nfsm_rpchead(struct ucred *cr, int nmflag, int procid,
 			  int auth_type, int auth_len,
 			  struct mbuf *mrest, int mrest_len,
-			  struct mbuf **mbp, u_int32_t *xidp);
+			  struct mbuf **mbp, u_int32_t **xidpp);
 
 #define	M_HASCL(m)	((m)->m_flags & M_EXT)
 #define	NFSMINOFF(m) \