afs: Translate VNOSERVICE to ETIMEDOUT

Some fileservers will kill calls that are taking too long with the
VNOSERVICE abort code. Our logic for retrying calls is already aware
of this usage, but if we cannot retry the call, we still just return
VNOSERVICE as an error code to our caller.

Don't return this raw, since has the same value as ENOBUFS, which can
cause a confusing error message from logs or applications ("No buffer
space available"). Return ETIMEDOUT instead.

Change-Id: Ic16422585a10cda7f21646a27c92f690b131ce9b
Reviewed-on: http://gerrit.openafs.org/10766
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Andrew Deason <adeason@sinenomine.net>

src/afs/afs_error.c

@@ -287,6 +287,9 @@ afs_CheckCode(afs_int32 acode, struct vrequest *areq, int where)
 	    ENOSPC
 #endif
 	    ;
+    /* Some fileservers kill overly-idle calls with VNOSERVICE. */
+    if (acode == VNOSERVICE)
+	return ETIMEDOUT;
 
     return acode;