ceph: use single osd op reply msg

Use a single ceph_msg for the osd reply, even when we are getting multiple
replies.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/osd_client.c

@@ -13,7 +13,8 @@
 #include "decode.h"
 #include "auth.h"
 
-#define OSD_REPLY_RESERVE_FRONT_LEN	512
+#define OSD_OP_FRONT_LEN	4096
+#define OSD_OPREPLY_FRONT_LEN	512
 
 const static struct ceph_connection_operations osd_con_ops;
 
@@ -75,17 +76,6 @@ static void calc_layout(struct ceph_osd_client *osdc,
 	     req->r_oid, req->r_oid_len, objoff, objlen, req->r_num_pages);
 }
 
-static void remove_replies(struct ceph_osd_request *req)
-{
-	int i;
-	int max = ARRAY_SIZE(req->replies);
-
-	for (i=0; i<max; i++) {
-		if (req->replies[i])
-			ceph_msg_put(req->replies[i]);
-	}
-}
-
 /*
  * requests
  */
@@ -99,7 +89,6 @@ void ceph_osdc_release_request(struct kref *kref)
 		ceph_msg_put(req->r_request);
 	if (req->r_reply)
 		ceph_msg_put(req->r_reply);
-	remove_replies(req);
 	if (req->r_con_filling_msg) {
 		dout("release_request revoking pages %p from con %p\n",
 		     req->r_pages, req->r_con_filling_msg);
@@ -117,60 +106,6 @@ void ceph_osdc_release_request(struct kref *kref)
 		kfree(req);
 }
 
-static int alloc_replies(struct ceph_osd_request *req, int num_reply)
-{
-	int i;
-	int max = ARRAY_SIZE(req->replies);
-
-	BUG_ON(num_reply > max);
-
-	for (i=0; i<num_reply; i++) {
-		req->replies[i] = ceph_msg_new(0, OSD_REPLY_RESERVE_FRONT_LEN, 0, 0, NULL);
-		if (IS_ERR(req->replies[i])) {
-			int j;
-			int err = PTR_ERR(req->replies[i]);
-			for (j = 0; j<=i; j++) {
-				ceph_msg_put(req->replies[j]);
-			}
-			return err;
-		}
-	}
-
-	for (; i<max; i++) {
-		req->replies[i] = NULL;
-	}
-
-	req->cur_reply = 0;
-
-	return 0;
-}
-
-static struct ceph_msg *__get_next_reply(struct ceph_connection *con,
-				       struct ceph_osd_request *req,
-				       int front_len)
-{
-	struct ceph_msg *reply;
-	if (req->r_con_filling_msg) {
-		dout("revoking reply msg %p from old con %p\n", req->r_reply,
-		     req->r_con_filling_msg);
-		ceph_con_revoke_message(req->r_con_filling_msg, req->r_reply);
-		ceph_con_put(req->r_con_filling_msg);
-		req->cur_reply = 0;
-	}
-	reply = req->replies[req->cur_reply];
-	if (!reply || front_len > OSD_REPLY_RESERVE_FRONT_LEN) {
-		/* maybe we can allocate it now? */
-		reply = ceph_msg_new(0, front_len, 0, 0, NULL);
-		if (!reply || IS_ERR(reply)) {
-			pr_err(" reply alloc failed, front_len=%d\n", front_len);
-			return ERR_PTR(-ENOMEM);
-		}
-	}
-	req->r_con_filling_msg = ceph_con_get(con);
-	req->r_reply = ceph_msg_get(reply); /* for duration of read over socket */
-	return ceph_msg_get(reply);
-}
-
 /*
  * build new request AND message, calculate layout, and adjust file
  * extent as needed.
@@ -201,7 +136,7 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	void *p;
 	int num_op = 1 + do_sync;
 	size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
-	int err, i;
+	int i;
 
 	if (use_mempool) {
 		req = mempool_alloc(osdc->req_mempool, GFP_NOFS);
@@ -212,13 +147,6 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 	if (req == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	err = alloc_replies(req, num_reply);
-	if (err) {
-		ceph_osdc_put_request(req);
-		return ERR_PTR(-ENOMEM);
-	}
-	req->r_num_prealloc_reply = num_reply;
-
 	req->r_osdc = osdc;
 	req->r_mempool = use_mempool;
 	kref_init(&req->r_kref);
@@ -229,7 +157,19 @@ struct ceph_osd_request *ceph_osdc_new_request(struct ceph_osd_client *osdc,
 
 	WARN_ON((flags & (CEPH_OSD_FLAG_READ|CEPH_OSD_FLAG_WRITE)) == 0);
 
-	/* create message; allow space for oid */
+	/* create reply message */
+	if (use_mempool)
+		msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);
+	else
+		msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY,
+				   OSD_OPREPLY_FRONT_LEN, 0, 0, NULL);
+	if (IS_ERR(msg)) {
+		ceph_osdc_put_request(req);
+		return ERR_PTR(PTR_ERR(msg));
+	}
+	req->r_reply = msg;
+
+	/* create request message; allow space for oid */
 	msg_size += 40;
 	if (snapc)
 		msg_size += sizeof(u64) * snapc->num_snaps;
@@ -819,21 +759,11 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg,
 	 * avoid a (safe but slower) revoke later.
 	 */
 	if (req->r_con_filling_msg == con && req->r_reply == msg) {
-		dout(" got pages, dropping con_filling_msg ref %p\n", con);
+		dout(" dropping con_filling_msg ref %p\n", con);
 		req->r_con_filling_msg = NULL;
 		ceph_con_put(con);
 	}
 
-	if (req->r_reply) {
-		/*
-		 * once we see the message has been received, we don't
-		 * need a ref (which is only needed for revoking
-		 * pages)
-		 */
-		ceph_msg_put(req->r_reply);
-		req->r_reply = NULL;
-	}
-
 	if (!req->r_got_reply) {
 		unsigned bytes;
 
@@ -1249,11 +1179,17 @@ int ceph_osdc_init(struct ceph_osd_client *osdc, struct ceph_client *client)
 	if (!osdc->req_mempool)
 		goto out;
 
-	err = ceph_msgpool_init(&osdc->msgpool_op, 4096, 10, true);
+	err = ceph_msgpool_init(&osdc->msgpool_op, OSD_OP_FRONT_LEN, 10, true);
 	if (err < 0)
 		goto out_mempool;
+	err = ceph_msgpool_init(&osdc->msgpool_op_reply,
+				OSD_OPREPLY_FRONT_LEN, 10, true);
+	if (err < 0)
+		goto out_msgpool;
 	return 0;
 
+out_msgpool:
+	ceph_msgpool_destroy(&osdc->msgpool_op);
 out_mempool:
 	mempool_destroy(osdc->req_mempool);
 out:
@@ -1271,6 +1207,7 @@ void ceph_osdc_stop(struct ceph_osd_client *osdc)
 	remove_old_osds(osdc, 1);
 	mempool_destroy(osdc->req_mempool);
 	ceph_msgpool_destroy(&osdc->msgpool_op);
+	ceph_msgpool_destroy(&osdc->msgpool_op_reply);
 }
 
 /*
@@ -1405,16 +1342,29 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
 	if (!req) {
 		*skip = 1;
 		m = NULL;
-		pr_info("alloc_msg unknown tid %llu from osd%d\n", tid,
+		pr_info("get_reply unknown tid %llu from osd%d\n", tid,
 			osd->o_osd);
 		goto out;
 	}
-	m = __get_next_reply(con, req, front);
-	if (!m || IS_ERR(m)) {
-		*skip = 1;
-		goto out;
+
+	if (req->r_con_filling_msg) {
+		dout("get_reply revoking msg %p from old con %p\n",
+		     req->r_reply, req->r_con_filling_msg);
+		ceph_con_revoke_message(req->r_con_filling_msg, req->r_reply);
+		ceph_con_put(req->r_con_filling_msg);
 	}
 
+	if (front > req->r_reply->front.iov_len) {
+		pr_warning("get_reply front %d > preallocated %d\n",
+			   front, (int)req->r_reply->front.iov_len);
+		m = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, front, 0, 0, NULL);
+		if (IS_ERR(m))
+			goto out;
+		ceph_msg_put(req->r_reply);
+		req->r_reply = m;
+	}
+	m = ceph_msg_get(req->r_reply);
+
 	if (data_len > 0) {
 		err = __prepare_pages(con, hdr, req, tid, m);
 		if (err < 0) {
@@ -1424,6 +1374,8 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
 		}
 	}
 	*skip = 0;
+	req->r_con_filling_msg = ceph_con_get(con);
+	dout("get_reply tid %lld %p\n", tid, m);
 
 out:
 	mutex_unlock(&osdc->request_mutex);

fs/ceph/osd_client.h

@@ -53,7 +53,6 @@ struct ceph_osd_request {
 	int               r_flags;     /* any additional flags for the osd */
 	u32               r_sent;      /* >0 if r_request is sending/sent */
 	int               r_got_reply;
-	int		  r_num_prealloc_reply;
 
 	struct ceph_osd_client *r_osdc;
 	struct kref       r_kref;
@@ -77,9 +76,6 @@ struct ceph_osd_request {
 	struct page     **r_pages;            /* pages for data payload */
 	int               r_pages_from_pool;
 	int               r_own_pages;        /* if true, i own page list */
-
-	struct ceph_msg   *replies[2];
-	int		  cur_reply;
 };
 
 struct ceph_osd_client {
@@ -106,6 +102,7 @@ struct ceph_osd_client {
 	mempool_t              *req_mempool;
 
 	struct ceph_msgpool	msgpool_op;
+	struct ceph_msgpool	msgpool_op_reply;
 };
 
 extern int ceph_osdc_init(struct ceph_osd_client *osdc,