vacuum: add a comment explaining a race in the vacuum code.

(This used to be ctdb commit 07f1ba54b1617fadd6fe83826dd8e76f37cea071)

1 files changed, 11 insertions, 0 deletions

diff --git a/ctdb/server/ctdb_vacuum.c b/ctdb/server/ctdb_vacuum.c
index 21ab1dbe88a..6a37e675a16 100644
--- a/ctdb/server/ctdb_vacuum.c
+++ b/ctdb/server/ctdb_vacuum.c
@@ -741,6 +741,17 @@ static int ctdb_process_delete_list(struct ctdb_db_context *ctdb_db,
 			 * outdata contains the list of records coming back
 			 * from the node: These are the records that the
 			 * remote node could not delete.
+			 *
+			 * NOTE: There is a problem here:
+			 *
+			 * When a node failed to delete the record, but
+			 * others succeeded, we may have created gaps in the
+			 * history of the record. Hence when a node dies, an
+			 * closed file handle might be resurrected or an open
+			 * file handle might be lost, leading to blocked access
+			 * or data corruption.
+			 *
+			 * TODO: This needs to be fixed!
 			 */
 			records = (struct ctdb_marshall_buffer *)outdata.dptr;
 			rec = (struct ctdb_rec_data *)&records->data[0];