Also set/clear P_KEEP in parent txn's cursors

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index cd99d67added76476fa83b611aa6d5354beb26bd..df88adcd27edad2cb19a50900929bb40fa3a532b 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1326,6 +1326,44 @@ 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.
+ * @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.
+ */
+static void
+mdb_cursorpages_mark(MDB_cursor *mc, unsigned pflags)
+{
+       MDB_txn *txn = mc->mc_txn;
+       MDB_cursor *m2, *m3;
+       MDB_xcursor *mx;
+       unsigned i, j;
+
+       if (mc->mc_flags & C_UNTRACK)
+               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 (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))
+                                               break;
+                                       /* Cursor backups have mx malloced at the end of m2 */
+                                       mx = (m3 == mc ? m3->mc_xcursor : (MDB_xcursor *)(m3+1));
+                               }
+                       }
+               }
+               if (i == 0)
+                       break;
+       }
+}
+
 static int mdb_page_flush(MDB_txn *txn);
 
 /**    Spill pages from the dirty list back to disk.
@@ -1404,34 +1442,9 @@ mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
                        }
                }
        }
-       /* Mark all the pages of active cursors we want to preserve */
-       for (i=0; i<txn->mt_numdbs; i++) {
-               MDB_cursor *mc = txn->mt_cursors[i];
-               /* See if m0 is tracked or not */
-               if (i == m0->mc_dbi && !(m0->mc_flags & C_UNTRACK)) {
-                               /* nope. tack it on in front */
-                               m0->mc_next = mc;
-                               mc = m0;
-               }
-               for (; mc; mc=mc->mc_next) {
-                       if (mc->mc_flags & C_INITIALIZED) {
-                               for (j=0; j<mc->mc_snum; j++) {
-                                       if (mc->mc_pg[j]->mp_flags & P_DIRTY)
-                                               mc->mc_pg[j]->mp_flags |= P_KEEP;
-                               }
-                               if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
-                                       MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;
-                                       if (mx->mc_flags & C_INITIALIZED) {
-                                               for (j=0; j<mx->mc_snum; j++) {
-                                                       if ((mx->mc_pg[j]->mp_flags & (P_SUBP|P_DIRTY))
-                                                                       == P_DIRTY)
-                                                               mx->mc_pg[j]->mp_flags |= P_KEEP;
-                                               }
-                                       }
-                               }
-                       }
-               }
-       }
+
+       /* Preserve pages used by cursors */
+       mdb_cursorpages_mark(m0, P_DIRTY);
 
        /* Save the page IDs of all the pages we're flushing */
        for (i=1; i<=dl[0].mid; i++) {
@@ -1461,6 +1474,9 @@ mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
        mdb_midl_sort(txn->mt_spill_pgs);
 
        rc = mdb_page_flush(txn);
+
+       mdb_cursorpages_mark(m0, P_DIRTY|P_KEEP);
+
        if (rc == 0) {
                txn->mt_dirty_room = MDB_IDL_UM_MAX - dl[0].mid;
                txn->mt_flags |= MDB_TXN_SPILLS;
@@ -6216,6 +6232,7 @@ mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
 static void
 mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
 {
+       mc->mc_next = NULL;
        mc->mc_backup = NULL;
        mc->mc_dbi = dbi;
        mc->mc_txn = txn;