[CRIU] [PATCH] fdstore: Unlimit fdstore queue on start

[Cyrill Gorcunov]

We use fdstore intensively for example when handling
bindmounted sockets and ghost dgram sockets. The system
limit for per-socket queue may not be enough if someone
generate lots of ghost sockets (150 and more as been
detected on default fedora 27).

To make it operatable lets unlimit fdstore queue size
on startup.

Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
 criu/fdstore.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/criu/fdstore.c b/criu/fdstore.c
index 8d3a6c89b1dc..88a5a9a153cf 100644
--- a/criu/fdstore.c
+++ b/criu/fdstore.c
@@ -20,6 +20,8 @@ static struct fdstore_desc {
 
 int fdstore_init(void)
 {
+	/* In kernel a bufsize has type int and a value is doubled. */
+	uint32_t buf[2] = { INT_MAX / 2, INT_MAX / 2 };
 	struct sockaddr_un addr;
 	unsigned int addrlen;
 	struct stat st;
@@ -44,6 +46,13 @@ int fdstore_init(void)
 		return -1;
 	}
 
+	if (setsockopt(sk, SOL_SOCKET, SO_SNDBUFFORCE, &buf[0], sizeof(buf[0])) < 0 ||
+	    setsockopt(sk, SOL_SOCKET, SO_RCVBUFFORCE, &buf[1], sizeof(buf[1])) < 0) {
+		pr_perror("Unable to set SO_SNDBUFFORCE/SO_RCVBUFFORCE");
+		close(sk);
+		return -1;
+	}
+
 	addr.sun_family = AF_UNIX;
 	addrlen = snprintf(addr.sun_path, sizeof(addr.sun_path), "X/criu-fdstore-%"PRIx64, st.st_ino);
 	addrlen += sizeof(addr.sun_family);
@@ -79,11 +88,13 @@ int fdstore_init(void)
 int fdstore_add(int fd)
 {
 	int sk = get_service_fd(FDSTORE_SK_OFF);
-	int id;
+	int id, ret;
 
 	mutex_lock(&desc->lock);
 
-	if (send_fd(sk, NULL, 0, fd)) {
+	ret = send_fd(sk, NULL, 0, fd);
+	if (ret) {
+		pr_perror("Can't send fd %d into store\n", fd);
 		mutex_unlock(&desc->lock);
 		return -1;
 	}
-- 
2.14.4