SUNRPC set gss gc_expiry to full lifetime

Only use the default GSSD_MIN_TIMEOUT if the gss downcall timeout is zero.
Store the full lifetime in gc_expiry (not 3/4 of the lifetime) as subsequent
patches will use the gc_expiry to determine buffered WRITE behavior in the
face of expired or soon to be expired gss credentials.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/auth_gss/auth_gss.c

@@ -192,17 +192,23 @@ gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct
 	const void *q;
 	unsigned int seclen;
 	unsigned int timeout;
+	unsigned long now = jiffies;
 	u32 window_size;
 	int ret;
 
-	/* First unsigned int gives the lifetime (in seconds) of the cred */
+	/* First unsigned int gives the remaining lifetime in seconds of the
+	 * credential - e.g. the remaining TGT lifetime for Kerberos or
+	 * the -t value passed to GSSD.
+	 */
 	p = simple_get_bytes(p, end, &timeout, sizeof(timeout));
 	if (IS_ERR(p))
 		goto err;
 	if (timeout == 0)
 		timeout = GSSD_MIN_TIMEOUT;
-	ctx->gc_expiry = jiffies + (unsigned long)timeout * HZ * 3 / 4;
-	/* Sequence number window. Determines the maximum number of simultaneous requests */
+	ctx->gc_expiry = now + ((unsigned long)timeout * HZ);
+	/* Sequence number window. Determines the maximum number of
+	 * simultaneous requests
+	 */
 	p = simple_get_bytes(p, end, &window_size, sizeof(window_size));
 	if (IS_ERR(p))
 		goto err;
@@ -237,9 +243,12 @@ gss_fill_context(const void *p, const void *end, struct gss_cl_ctx *ctx, struct
 		p = ERR_PTR(ret);
 		goto err;
 	}
+	dprintk("RPC:       %s Success. gc_expiry %lu now %lu timeout %u\n",
+		__func__, ctx->gc_expiry, now, timeout);
 	return q;
 err:
-	dprintk("RPC:       %s returning %ld\n", __func__, -PTR_ERR(p));
+	dprintk("RPC:       %s returns %ld gc_expiry %lu now %lu timeout %u\n",
+		__func__, -PTR_ERR(p), ctx->gc_expiry, now, timeout);
 	return p;
 }