nfsd: export upcalls must not return ESTALE when mountd is down

If the rpc.mountd daemon goes down, then that should not cause all
exports to start failing with ESTALE errors. Let's explicitly
distinguish between the cache upcall cases that need to time out,
and those that do not.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

3 files changed, 50 insertions, 27 deletions

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index e93f06ec180d..54ae5be62f6a 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -180,6 +180,11 @@ static struct cache_head *rsi_alloc(void)
 		return NULL;
 }
 
+static int rsi_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return sunrpc_cache_pipe_upcall_timeout(cd, h);
+}
+
 static void rsi_request(struct cache_detail *cd,
 		       struct cache_head *h,
 		       char **bpp, int *blen)
@@ -278,6 +283,7 @@ static const struct cache_detail rsi_cache_template = {
 	.hash_size	= RSI_HASHMAX,
 	.name           = "auth.rpcsec.init",
 	.cache_put      = rsi_put,
+	.cache_upcall	= rsi_upcall,
 	.cache_request  = rsi_request,
 	.cache_parse    = rsi_parse,
 	.match		= rsi_match,
@@ -424,6 +430,11 @@ rsc_alloc(void)
 		return NULL;
 }
 
+static int rsc_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return -EINVAL;
+}
+
 static int rsc_parse(struct cache_detail *cd,
 		     char *mesg, int mlen)
 {
@@ -550,6 +561,7 @@ static const struct cache_detail rsc_cache_template = {
 	.hash_size	= RSC_HASHMAX,
 	.name		= "auth.rpcsec.context",
 	.cache_put	= rsc_put,
+	.cache_upcall	= rsc_upcall,
 	.cache_parse	= rsc_parse,
 	.match		= rsc_match,
 	.init		= rsc_init,
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 8a8e3528293c..7f2e5d818e05 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -38,7 +38,6 @@
 
 static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
 static void cache_revisit_request(struct cache_head *item);
-static bool cache_listeners_exist(struct cache_detail *detail);
 
 static void cache_init(struct cache_head *h, struct cache_detail *detail)
 {
@@ -225,13 +224,6 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 }
 EXPORT_SYMBOL_GPL(sunrpc_cache_update);
 
-static int cache_make_upcall(struct cache_detail *cd, struct cache_head *h)
-{
-	if (cd->cache_upcall)
-		return cd->cache_upcall(cd, h);
-	return sunrpc_cache_pipe_upcall(cd, h);
-}
-
 static inline int cache_is_valid(struct cache_head *h)
 {
 	if (!test_bit(CACHE_VALID, &h->flags))
@@ -304,17 +296,14 @@ int cache_check(struct cache_detail *detail,
 		   (h->expiry_time != 0 && age > refresh_age/2)) {
 		dprintk("RPC:       Want update, refage=%lld, age=%lld\n",
 				refresh_age, age);
-		if (!test_and_set_bit(CACHE_PENDING, &h->flags)) {
-			switch (cache_make_upcall(detail, h)) {
-			case -EINVAL:
-				rv = try_to_negate_entry(detail, h);
-				break;
-			case -EAGAIN:
-				cache_fresh_unlocked(h, detail);
-				break;
-			}
-		} else if (!cache_listeners_exist(detail))
+		switch (detail->cache_upcall(detail, h)) {
+		case -EINVAL:
 			rv = try_to_negate_entry(detail, h);
+			break;
+		case -EAGAIN:
+			cache_fresh_unlocked(h, detail);
+			break;
+		}
 	}
 
 	if (rv == -EAGAIN) {
@@ -1196,20 +1185,12 @@ static bool cache_listeners_exist(struct cache_detail *detail)
  *
  * Each request is at most one page long.
  */
-int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
+static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 {
-
 	char *buf;
 	struct cache_request *crq;
 	int ret = 0;
 
-	if (!detail->cache_request)
-		return -EINVAL;
-
-	if (!cache_listeners_exist(detail)) {
-		warn_no_listener(detail);
-		return -EINVAL;
-	}
 	if (test_bit(CACHE_CLEANED, &h->flags))
 		/* Too late to make an upcall */
 		return -EAGAIN;
@@ -1243,8 +1224,26 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 	}
 	return ret;
 }
+
+int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
+{
+	if (test_and_set_bit(CACHE_PENDING, &h->flags))
+		return 0;
+	return cache_pipe_upcall(detail, h);
+}
 EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall);
 
+int sunrpc_cache_pipe_upcall_timeout(struct cache_detail *detail,
+				     struct cache_head *h)
+{
+	if (!cache_listeners_exist(detail)) {
+		warn_no_listener(detail);
+		return -EINVAL;
+	}
+	return sunrpc_cache_pipe_upcall(detail, h);
+}
+EXPORT_SYMBOL_GPL(sunrpc_cache_pipe_upcall_timeout);
+
 /*
  * parse a message from user-space and pass it
  * to an appropriate cache
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 04aa80a2d752..6c8f802c4261 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -148,6 +148,11 @@ static struct cache_head *ip_map_alloc(void)
 		return NULL;
 }
 
+static int ip_map_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return sunrpc_cache_pipe_upcall(cd, h);
+}
+
 static void ip_map_request(struct cache_detail *cd,
 				  struct cache_head *h,
 				  char **bpp, int *blen)
@@ -467,6 +472,11 @@ static struct cache_head *unix_gid_alloc(void)
 		return NULL;
 }
 
+static int unix_gid_upcall(struct cache_detail *cd, struct cache_head *h)
+{
+	return sunrpc_cache_pipe_upcall_timeout(cd, h);
+}
+
 static void unix_gid_request(struct cache_detail *cd,
 			     struct cache_head *h,
 			     char **bpp, int *blen)
@@ -584,6 +594,7 @@ static const struct cache_detail unix_gid_cache_template = {
 	.hash_size	= GID_HASHMAX,
 	.name		= "auth.unix.gid",
 	.cache_put	= unix_gid_put,
+	.cache_upcall	= unix_gid_upcall,
 	.cache_request	= unix_gid_request,
 	.cache_parse	= unix_gid_parse,
 	.cache_show	= unix_gid_show,
@@ -881,6 +892,7 @@ static const struct cache_detail ip_map_cache_template = {
 	.hash_size	= IP_HASHMAX,
 	.name		= "auth.unix.ip",
 	.cache_put	= ip_map_put,
+	.cache_upcall	= ip_map_upcall,
 	.cache_request	= ip_map_request,
 	.cache_parse	= ip_map_parse,
 	.cache_show	= ip_map_show,