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, 16 insertions, 0 deletions

diff --git a/sys/fs/nfs/nfsdport.h b/sys/fs/nfs/nfsdport.h
index a3f05db..529ada2 100644
--- a/sys/fs/nfs/nfsdport.h
+++ b/sys/fs/nfs/nfsdport.h
@@ -57,6 +57,22 @@ struct nfsexstuff {
 	int	nes_secflavors[MAXSECFLAVORS];	/* and the flavors */
 };
 
+/*
+ * These are NO-OPS for BSD until Isilon upstreams EXITCODE support.
+ * EXITCODE is an in-memory ring buffer that holds the routines failing status.
+ * This is a valuable tool to use when debugging and analyzing issues.
+ * In addition to recording a routine's failing status, it offers
+ * logging of routines for call stack tracing.
+ * EXITCODE should be used only in routines that return a true errno value, as
+ * that value will be formatted to a displayable errno string.  Routines that 
+ * return regular int status that are not true errno should not set EXITCODE.
+ * If you want to log routine tracing, you can add EXITCODE(0) to any routine.
+ * NFS extended the EXITCODE with EXITCODE2 to record either the routine's
+ * exit errno status or the nd_repstat.
+ */
+#define	NFSEXITCODE(error)
+#define	NFSEXITCODE2(error, nd)
+
 #define	NFSVNO_EXINIT(e)		((e)->nes_exflag = 0)
 #define	NFSVNO_EXPORTED(e)		((e)->nes_exflag & MNT_EXPORTED)
 #define	NFSVNO_EXRDONLY(e)		((e)->nes_exflag & MNT_EXRDONLY)