[sheepdog] [PATCH consolidate the MAX_EVENT_BUF_SIZE definitions

[Christoph Hellwig]

The accord, local and zookeeper drivers all need an upper bound of the
message size the sheepdog might send for their communication queues.

Centralize the definition into a single place, and make sure we never
send larger messages from the core sheepdog code.

Signed-off-by: Christoph Hellwig <hch at lst.de>

---
 sheep/cluster.h           |    3 +++
 sheep/cluster/accord.c    |    4 +---
 sheep/cluster/local.c     |    3 +--
 sheep/cluster/zookeeper.c |    3 +--
 sheep/group.c             |    2 ++
 5 files changed, 8 insertions(+), 7 deletions(-)

Index: sheepdog/sheep/cluster.h
===================================================================
--- sheepdog.orig/sheep/cluster.h	2012-05-20 16:18:51.094558848 +0200
+++ sheepdog/sheep/cluster.h	2012-05-20 19:37:26.656020841 +0200
@@ -22,6 +22,9 @@
 #include "sheep.h"
 #include "logger.h"
 
+/* maximum payload size sent in ->notify and ->unblock */
+#define SD_MAX_EVENT_BUF_SIZE (64 * 1024)
+
 enum cluster_join_result {
 	CJ_RES_SUCCESS, /* Success */
 	CJ_RES_FAIL, /* Fail to join.  The joining node has an invalidepoch. */
Index: sheepdog/sheep/cluster/accord.c
===================================================================
--- sheepdog.orig/sheep/cluster/accord.c	2012-05-20 16:18:51.094558848 +0200
+++ sheepdog/sheep/cluster/accord.c	2012-05-20 19:36:44.304019756 +0200
@@ -23,8 +23,6 @@
 #include "event.h"
 #include "work.h"
 
-#define MAX_EVENT_BUF_SIZE (64 * 1024)
-
 #define BASE_FILE "/sheepdog"
 #define LOCK_FILE BASE_FILE "/lock"
 #define QUEUE_FILE BASE_FILE "/queue"
@@ -40,7 +38,7 @@ struct acrd_event {
 	struct sd_node sender;
 
 	size_t buf_len;
-	uint8_t buf[MAX_EVENT_BUF_SIZE];
+	uint8_t buf[SD_MAX_EVENT_BUF_SIZE];
 
 	size_t nr_nodes; /* the number of sheep */
 	struct sd_node nodes[SD_MAX_NODES];
Index: sheepdog/sheep/cluster/local.c
===================================================================
--- sheepdog.orig/sheep/cluster/local.c	2012-05-20 19:35:32.388017915 +0200
+++ sheepdog/sheep/cluster/local.c	2012-05-20 19:37:33.636021021 +0200
@@ -25,7 +25,6 @@
 #include "work.h"
 
 #define MAX_EVENTS 500
-#define MAX_EVENT_BUF_SIZE (64 * 1024)
 
 const char *shmfile = "/tmp/sheepdog_shm";
 static int shmfd;
@@ -46,7 +45,7 @@ struct local_event {
 	struct sd_node sender;
 
 	size_t buf_len;
-	uint8_t buf[MAX_EVENT_BUF_SIZE];
+	uint8_t buf[SD_MAX_EVENT_BUF_SIZE];
 
 	size_t nr_nodes; /* the number of sheep processes */
 	struct sd_node nodes[SD_MAX_NODES];
Index: sheepdog/sheep/cluster/zookeeper.c
===================================================================
--- sheepdog.orig/sheep/cluster/zookeeper.c	2012-05-20 16:18:51.094558848 +0200
+++ sheepdog/sheep/cluster/zookeeper.c	2012-05-20 19:38:10.472021965 +0200
@@ -23,7 +23,6 @@
 #include "event.h"
 #include "work.h"
 
-#define MAX_EVENT_BUF_SIZE (64 * 1024)
 #define SESSION_TIMEOUT 30000		/* millisecond */
 #define MEMBER_CREATE_TIMEOUT SESSION_TIMEOUT
 #define MEMBER_CREATE_INTERVAL 10	/* millisecond */
@@ -82,7 +81,7 @@ struct zk_event {
 	int callbacked; /* set non-zero after sd_block_handler() was called */
 
 	size_t buf_len;
-	uint8_t buf[MAX_EVENT_BUF_SIZE];
+	uint8_t buf[SD_MAX_EVENT_BUF_SIZE];
 };
 
 static int zk_notify_blocked;
Index: sheepdog/sheep/group.c
===================================================================
--- sheepdog.orig/sheep/group.c	2012-05-20 16:18:51.098558849 +0200
+++ sheepdog/sheep/group.c	2012-05-20 19:38:56.260023135 +0200
@@ -247,6 +247,8 @@ static struct vdi_op_message *prepare_cl
 	else
 		size = sizeof(*msg);
 
+	assert(size <= SD_MAX_EVENT_BUF_SIZE);
+
 	msg = zalloc(size);
 	if (!msg) {
 		eprintf("failed to allocate memory\n");