From: Andrew Tridgell <tridge@samba.org>
Date: Mon, 18 Dec 2006 02:24:02 +0000 (+1100)
Subject: added storage of extended ltdb header information
X-Git-Tag: tevent-0.9.20~348^2~3000
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3804b8b3e400af8ec94a1778df5f51e8337ef2ff;p=thirdparty%2Fsamba.git

added storage of extended ltdb header information
(This used to be ctdb commit a18c9411081a4e5997bf030fa924abfc33fb3310)
---

diff --git a/ctdb/common/ctdb_call.c b/ctdb/common/ctdb_call.c
index a2219403a25..441e22b613c 100644
--- a/ctdb/common/ctdb_call.c
+++ b/ctdb/common/ctdb_call.c
@@ -34,18 +34,20 @@ static int ctdb_call_local(struct ctdb_context *ctdb, TDB_DATA key, int call_id,
 	struct ctdb_call *c;
 	struct ctdb_registered_call *fn;
 	TDB_DATA data;
+	struct ctdb_ltdb_header header;
+	int ret;
 
 	c = talloc(ctdb, struct ctdb_call);
 	CTDB_NO_MEMORY(ctdb, c);
 
-	data = tdb_fetch(ctdb->ltdb, key);
+	ret = ctdb_ltdb_fetch(ctdb, c, key, &header, &data);
+	if (ret != 0) return -1;
 	
 	c->key = key;
 	c->call_data = call_data;
 	c->record_data.dptr = talloc_memdup(c, data.dptr, data.dsize);
 	c->record_data.dsize = data.dsize;
 	CTDB_NO_MEMORY(ctdb, c->record_data.dptr);
-	if (data.dptr) free(data.dptr);
 	c->new_data = NULL;
 	c->reply_data = NULL;
 
@@ -58,13 +60,12 @@ static int ctdb_call_local(struct ctdb_context *ctdb, TDB_DATA key, int call_id,
 	}
 
 	if (fn->fn(c) != 0) {
-		free(c->record_data.dptr);
 		ctdb_set_error(ctdb, "ctdb_call %u failed\n", call_id);
 		return -1;
 	}
 
 	if (c->new_data) {
-		if (tdb_store(ctdb->ltdb, key, *c->new_data, TDB_REPLACE) != 0) {
+		if (ctdb_ltdb_store(ctdb, key, &header, *c->new_data) != 0) {
 			ctdb_set_error(ctdb, "ctdb_call tdb_store failed\n");
 			return -1;
 		}
diff --git a/ctdb/common/ctdb_ltdb.c b/ctdb/common/ctdb_ltdb.c
index 4fe316f4db9..004ab254d5d 100644
--- a/ctdb/common/ctdb_ltdb.c
+++ b/ctdb/common/ctdb_ltdb.c
@@ -40,3 +40,72 @@ int ctdb_attach(struct ctdb_context *ctdb, const char *name, int tdb_flags,
 	}
 	return 0;
 }
+
+
+/*
+  construct an initial header for a record with no ltdb header yet
+*/
+static void ltdb_initial_header(struct ctdb_context *ctdb, 
+				TDB_DATA key,
+				struct ctdb_ltdb_header *header)
+{
+	header->rsn = 0;
+	header->dmaster = ctdb_hash(&key) % ctdb->num_nodes;
+	header->laccessor = header->dmaster;
+	header->lacount = 0;
+}
+
+
+/*
+  fetch a record from the ltdb, separating out the header information
+  and returning the body of the record. A valid (initial) header is
+  returned if the record is not present
+*/
+int ctdb_ltdb_fetch(struct ctdb_context *ctdb, TALLOC_CTX *mem_ctx,
+		    TDB_DATA key, struct ctdb_ltdb_header *header, TDB_DATA *data)
+{
+	TDB_DATA rec;
+
+	rec = tdb_fetch(ctdb->ltdb, key);
+	if (rec.dsize < sizeof(*header)) {
+		/* return an initial header */
+		ltdb_initial_header(ctdb, key, header);
+		data->dptr = NULL;
+		data->dsize = 0;
+		return 0;
+	}
+
+	*header = *(struct ctdb_ltdb_header *)rec.dptr;
+
+	data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header);
+	data->dptr = talloc_memdup(mem_ctx, sizeof(struct ctdb_ltdb_header)+rec.dptr,
+				   data->dsize);
+	CTDB_NO_MEMORY(ctdb, data->dptr);
+
+	return 0;
+}
+
+
+/*
+  fetch a record from the ltdb, separating out the header information
+  and returning the body of the record. A valid (initial) header is
+  returned if the record is not present
+*/
+int ctdb_ltdb_store(struct ctdb_context *ctdb, TDB_DATA key, 
+		    struct ctdb_ltdb_header *header, TDB_DATA data)
+{
+	TDB_DATA rec;
+	int ret;
+
+	rec.dsize = sizeof(struct ctdb_ltdb_header) + data.dsize;
+	rec.dptr = talloc_size(ctdb, rec.dsize);
+	CTDB_NO_MEMORY(ctdb, rec.dptr);
+
+	memcpy(rec.dptr, header, sizeof(*header));
+	memcpy(rec.dptr + sizeof(*header), data.dptr, data.dsize);
+	
+	ret = tdb_store(ctdb->ltdb, key, rec, TDB_REPLACE);
+	talloc_free(rec.dptr);
+
+	return ret;
+}
diff --git a/ctdb/include/ctdb_private.h b/ctdb/include/ctdb_private.h
index 32f258b2bf8..bbddd74b589 100644
--- a/ctdb/include/ctdb_private.h
+++ b/ctdb/include/ctdb_private.h
@@ -101,13 +101,26 @@ struct ctdb_context {
 /* arbitrary maximum timeout for ctdb operations */
 #define CTDB_REQ_TIMEOUT 10
 
+/*
+  the extended header for records in the ltdb
+*/
+struct ctdb_ltdb_header {
+	uint64_t rsn;
+	uint32_t dmaster;
+	uint32_t laccessor;
+	uint32_t lacount;
+};
+
 
 /*
   operation IDs
 */
 enum ctdb_operation {
 	CTDB_REQ_CALL   = 0,
-	CTDB_REPLY_CALL = 1
+	CTDB_REPLY_CALL = 1,
+	CTDB_REPLY_REDIRECT = 2,
+	CTDB_REQ_DMASTER = 3,
+	CTDB_REPLY_DMASTER = 4,
 };
 
 /*
@@ -145,3 +158,9 @@ uint32_t ctdb_hash(TDB_DATA *key);
 void ctdb_request_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr);
 void ctdb_reply_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr);
 
+int ctdb_ltdb_fetch(struct ctdb_context *ctdb, TALLOC_CTX *mem_ctx,
+		    TDB_DATA key, struct ctdb_ltdb_header *header, TDB_DATA *data);
+int ctdb_ltdb_store(struct ctdb_context *ctdb, TDB_DATA key, 
+		    struct ctdb_ltdb_header *header, TDB_DATA data);
+
+