mdb_cursorpages_mark: Mark current txn and no more.

Ignore parent txn cursors since it is the current txn's dirty_list
which will be flushed. But check the current txn also when clearing,
since cursors can have pages which are dirty in a parent.

Check !mc_xcursor instead of !MDB_DUPSORT.  Equivalent for valid
data, but a bit safer if the sub-DB flags are corrupt.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index d1e12554cc9148d4d5382f6d19a8546b35ba2139..386a1dcc8c87b825efe741a4f535d57b9d1645f9 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1352,9 +1352,7 @@ mdb_dlist_free(MDB_txn *txn)
        dl[0].mid = 0;
 }
 
-/* Set or clear P_KEEP in non-overflow, non-sub pages in known cursors.
- * When clearing, only consider backup cursors (from parent txns) since
- * other P_KEEP flags have already been cleared.
+/* Set or clear P_KEEP in non-overflow, non-sub pages in this txn's cursors.
  * @param[in] mc A cursor handle for the current operation.
  * @param[in] pflags Flags of the pages to update:
  * P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
@@ -1363,7 +1361,7 @@ static void
 mdb_cursorpages_mark(MDB_cursor *mc, unsigned pflags)
 {
        MDB_txn *txn = mc->mc_txn;
-       MDB_cursor *m2, *m3;
+       MDB_cursor *m3;
        MDB_xcursor *mx;
        unsigned i, j;
 
@@ -1371,18 +1369,14 @@ mdb_cursorpages_mark(MDB_cursor *mc, unsigned pflags)
                mc = NULL;                              /* will find mc in mt_cursors */
        for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
                for (; mc; mc=mc->mc_next) {
-                       m2 = pflags == P_DIRTY ? mc : mc->mc_backup;
-                       for (; m2; m2 = m2->mc_backup) {
-                               for (m3=m2; m3->mc_flags & C_INITIALIZED; m3=&mx->mx_cursor) {
+                       for (m3 = mc; m3->mc_flags & C_INITIALIZED; m3 = &mx->mx_cursor) {
                                        for (j=0; j<m3->mc_snum; j++)
                                                if ((m3->mc_pg[j]->mp_flags & (P_SUBP|P_DIRTY|P_KEEP))
                                                                == pflags)
                                                        m3->mc_pg[j]->mp_flags ^= P_KEEP;
-                                       if (!(m3->mc_db->md_flags & MDB_DUPSORT))
+                                       mx = m3->mc_xcursor;
+                                       if (mx == NULL)
                                                break;
-                                       /* Cursor backups have mx malloced at the end of m2 */
-                                       mx = (m3 == mc ? m3->mc_xcursor : (MDB_xcursor *)(m3+1));
-                               }
                        }
                }
                if (i == 0)