Add DEXITCODE plumbing to NFS.

Isilon has the concept of an in-memory exit-code ring that saves the last exit
code of a function and allows for stack tracing. This is very helpful when
debugging tough issues.

This patch is essentially a no-op for BSD at this point, until we upstream
the dexitcode logic itself. The patch adds DEXITCODE calls to every NFS
function that returns an errno error code. A number of code paths were also
reorganized to have single exit paths, to reduce code duplication.

Submitted by:   David Kwan <dkwan@isilon.com>
Reviewed by:    rmacklem
Approved by:    zml (mentor)
MFC after:      2 weeks

1 files changed, 7 insertions, 4 deletions

diff --git a/sys/fs/nfs/nfs_commonkrpc.c b/sys/fs/nfs/nfs_commonkrpc.c
index f658ac8..ca629d2 100644
--- a/sys/fs/nfs/nfs_commonkrpc.c
+++ b/sys/fs/nfs/nfs_commonkrpc.c
@@ -166,7 +166,7 @@ newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
 	CLIENT *client;
 	struct netconfig *nconf;
 	struct socket *so;
-	int one = 1, retries, error;
+	int one = 1, retries, error = 0;
 	struct thread *td = curthread;
 
 	/*
@@ -222,7 +222,7 @@ newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
 	    nrp->nr_soproto, td->td_ucred, td);
 	if (error) {
 		td->td_ucred = origcred;
-		return (error);
+		goto out;
 	}
 	do {
 	    if (error != 0 && pktscale > 2)
@@ -253,7 +253,7 @@ newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
 	soclose(so);
 	if (error) {
 		td->td_ucred = origcred;
-		return (error);
+		goto out;
 	}
 
 	client = clnt_reconnect_create(nconf, saddr, nrp->nr_prog,
@@ -307,7 +307,10 @@ newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
 
 	/* Restore current thread's credentials. */
 	td->td_ucred = origcred;
-	return (0);
+
+out:
+	NFSEXITCODE(error);
+	return (error);
 }
 
 /*