ceph: name msgpools; useful error messages

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/msgpool.c b/fs/ceph/msgpool.c
index 10d3632..50fe5cc 100644
--- a/fs/ceph/msgpool.c
+++ b/fs/ceph/msgpool.c
@@ -10,8 +10,12 @@
 static void *alloc_fn(gfp_t gfp_mask, void *arg)
 {
 	struct ceph_msgpool *pool = arg;
+	void *p;
 
-	return ceph_msg_new(0, pool->front_len);
+	p = ceph_msg_new(0, pool->front_len);
+	if (!p)
+		pr_err("msgpool %s alloc failed\n", pool->name);
+	return p;
 }
 
 static void free_fn(void *element, void *arg)
@@ -20,12 +24,13 @@
 }
 
 int ceph_msgpool_init(struct ceph_msgpool *pool,
-		      int front_len, int size, bool blocking)
+		      int front_len, int size, bool blocking, const char *name)
 {
 	pool->front_len = front_len;
 	pool->pool = mempool_create(size, alloc_fn, free_fn, pool);
 	if (!pool->pool)
 		return -ENOMEM;
+	pool->name = name;
 	return 0;
 }
 
@@ -38,8 +43,8 @@
 				  int front_len)
 {
 	if (front_len > pool->front_len) {
-		pr_err("msgpool_get pool %p need front %d, pool size is %d\n",
-		       pool, front_len, pool->front_len);
+		pr_err("msgpool_get pool %s need front %d, pool size is %d\n",
+		       pool->name, front_len, pool->front_len);
 		WARN_ON(1);
 
 		/* try to alloc a fresh message */
diff --git a/fs/ceph/msgpool.h b/fs/ceph/msgpool.h
index 62a61c7..a362605f 100644
--- a/fs/ceph/msgpool.h
+++ b/fs/ceph/msgpool.h
@@ -9,12 +9,14 @@
  * avoid unexpected OOM conditions.
  */
 struct ceph_msgpool {
+	const char *name;
 	mempool_t *pool;
 	int front_len;          /* preallocated payload size */
 };
 
 extern int ceph_msgpool_init(struct ceph_msgpool *pool,
-			     int front_len, int size, bool blocking);
+			     int front_len, int size, bool blocking,
+			     const char *name);
 extern void ceph_msgpool_destroy(struct ceph_msgpool *pool);
 extern struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *,
 					 int front_len);
diff --git a/fs/ceph/osd_client.c b/fs/ceph/osd_client.c
index 97a3a57..c0aca73 100644
--- a/fs/ceph/osd_client.c
+++ b/fs/ceph/osd_client.c
@@ -1214,11 +1214,13 @@
 	if (!osdc->req_mempool)
 		goto out;
 
-	err = ceph_msgpool_init(&osdc->msgpool_op, OSD_OP_FRONT_LEN, 10, true);
+	err = ceph_msgpool_init(&osdc->msgpool_op, OSD_OP_FRONT_LEN, 10, true,
+				"osd_op");
 	if (err < 0)
 		goto out_mempool;
 	err = ceph_msgpool_init(&osdc->msgpool_op_reply,
-				OSD_OPREPLY_FRONT_LEN, 10, true);
+				OSD_OPREPLY_FRONT_LEN, 10, true,
+				"osd_op_reply");
 	if (err < 0)
 		goto out_msgpool;
 	return 0;