better error handling in ctdb_ltdb_lock_fetch_requeue()

(This used to be ctdb commit 1952be19f625dbe257050acebf468e7e6eb0da8c)

diff --git a/ctdb/common/ctdb_ltdb.c b/ctdb/common/ctdb_ltdb.c
index 132108e69b187172b86c99d8a8a3f2234875bba0..c523d5f9952fd1e9a61c857bba3c0b149536f96e 100644 (file)
--- a/ctdb/common/ctdb_ltdb.c
+++ b/ctdb/common/ctdb_ltdb.c
@@ -244,6 +244,12 @@ static void lock_fetch_callback(void *p)
    immediately satisfied until it can get the lock. This means that
    the main ctdb daemon will not block waiting for a chainlock held by
    a client
+
+   There are 3 possible return values:
+
+       0:    means that it got the lock immediately.
+      -1:    means that it failed to get the lock, and won't retry
+      -2:    means that it failed to get the lock immediately, but will retry
  */
 int ctdb_ltdb_lock_fetch_requeue(struct ctdb_db_context *ctdb_db, 
                                 TDB_DATA key, struct ctdb_ltdb_header *header, 
@@ -255,6 +261,12 @@ int ctdb_ltdb_lock_fetch_requeue(struct ctdb_db_context *ctdb_db,
        
        ret = tdb_chainlock_nonblock(tdb, key);
 
+       if (ret != 0 &&
+           !(errno == EACCES || errno == EAGAIN || errno == EDEADLK)) {
+               /* a hard failure - don't try again */
+               return -1;
+       }
+
        /* first the non-contended path */
        if (ret == 0) {
                ret = ctdb_ltdb_fetch(ctdb_db, key, header, hdr, data);
@@ -273,6 +285,11 @@ int ctdb_ltdb_lock_fetch_requeue(struct ctdb_db_context *ctdb_db,
 
        /* we get an extra reference to the packet here, to 
           stop it being freed in the top level packet handler */
-       (void)talloc_reference(ctdb_db, hdr);
-       return 0;
+       if (talloc_reference(ctdb_db, hdr) == NULL) {
+               talloc_free(h);
+               return -1;
+       }
+
+       /* now tell the caller than we will retry asynchronously */
+       return -2;
 }