[sheepdog] [PATCH RFC 5/5] sheep: retry when connect() or accept() fails with EMFILE

[Hitoshi Mitake]

This patch adds calling of shrink_sockfd() after connect() and
accept() when they return EMFILE.

These retries can be invoked twice at a maximum. This policy must be
improved in the future.

Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
---
 sheep/request.c      |    7 +++++++
 sheep/sockfd_cache.c |    6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/sheep/request.c b/sheep/request.c
index 3b43c76..8f3f840 100644
--- a/sheep/request.c
+++ b/sheep/request.c
@@ -828,8 +828,15 @@ static void listen_handler(int listen_fd, int events, void *data)
 	}
 
 	namesize = sizeof(from);
+
+	int retry = 2;
+retry_accept:
 	fd = accept(listen_fd, (struct sockaddr *)&from, &namesize);
 	if (fd < 0) {
+		if (errno == EMFILE && retry--) {
+			if (shrink_sockfd())
+				goto retry_accept;
+		}
 		sd_eprintf("failed to accept a new connection: %m");
 		return;
 	}
diff --git a/sheep/sockfd_cache.c b/sheep/sockfd_cache.c
index 37a6a5e..ffab647 100644
--- a/sheep/sockfd_cache.c
+++ b/sheep/sockfd_cache.c
@@ -390,9 +390,15 @@ grab:
 	}
 
 	/* Create a new cached connection for this node */
+	int retry = 2;
+retry_connect:
 	sd_dprintf("create cache connection %s:%d idx %d", name, port, idx);
 	fd = connect_to(name, port);
 	if (fd < 0) {
+		if (errno == EMFILE && retry--) {
+			if (shrink_sockfd())
+				goto retry_connect;
+		}
 		if (use_io) {
 			sd_eprintf("fallback to non-io connection");
 			fd = connect_to_addr(nid->addr, nid->port);
-- 
1.7.10.4