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idr can timeout and wrap/be reused quite quickly.

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If a noremote node hangs for an extended period, it is possible
that we might have a DMASTER request in flight for record A to that node.
Eventually we will reuse the idr, and may reuse it for a DMASTER request to a different node for a different record B.

If while the request for B is in flight,  the first tnode un-hangs and responds back
we would receive a dmaster reply for the wrong record.

This would cause a record to become perpetually locked, since inside the daemon we would tdb_chainlock(dmaster_reply->pdu->key)   but once the migration would complete we would chainunlock   idr->state->call->key

Adding code to verify that when we receive a dmaster reply packet that it does in fact match the exact same key that the state variable we have for the idr in flight.

(This used to be ctdb commit 2f6a870d7ff02ceb61fde242f752dccbfcb4cb37)
This commit is contained in:
Ronnie Sahlberg 2010-06-09 16:12:36 +10:00
parent 641da4c691
commit d9a3e1d0c0
1 changed files with 11 additions and 1 deletions
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12
ctdb/server/ctdb_call.c
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@ -276,6 +276,16 @@ static void ctdb_become_dmaster(struct ctdb_db_context *ctdb_db,
return;
}
if (key.dsize != state->call->key.dsize || memcmp(key.dptr, state->call->key.dptr, key.dsize)) {
DEBUG(DEBUG_ERR, ("Got bogus DMASTER packet reqid:%u\n from node %u. Key does not match key held in matching idr.", hdr->reqid, hdr->srcnode));
ret = ctdb_ltdb_unlock(ctdb_db, key);
if (ret != 0) {
DEBUG(DEBUG_ERR,(__location__ " ctdb_ltdb_unlock() failed with error %d\n", ret));
}
return;
}
if (hdr->reqid != state->reqid) {
/* we found a record but it was the wrong one */
DEBUG(DEBUG_ERR, ("Dropped orphan in ctdb_become_dmaster with reqid:%u\n from node %u", hdr->reqid, hdr->srcnode));
@ -289,7 +299,7 @@ static void ctdb_become_dmaster(struct ctdb_db_context *ctdb_db,
ctdb_call_local(ctdb_db, state->call, &header, state, &data, ctdb->pnn);
ret = ctdb_ltdb_unlock(ctdb_db, key);
ret = ctdb_ltdb_unlock(ctdb_db, state->call->key);
if (ret != 0) {
DEBUG(DEBUG_ERR,(__location__ " ctdb_ltdb_unlock() failed with error %d\n", ret));
}