Properly update the range of free-list writes when loose pages will be returned to the free-list

Author: kriszyp

dependencies/lmdb/libraries/liblmdb/mdb.c

@@ -4251,12 +4251,15 @@ mdb_freelist_save(MDB_txn *txn)
 				unsigned end = mop_len;
 				mop_len -= len;
 				unsigned start = mop_len > 0 ? mop_len - 1 : 0;
-				char do_write = env->me_freelist_written_start <= end && env->me_freelist_written_end >= start;
+				char do_write = freelist_written_start <= end && freelist_written_end >= start;
 				fl_writes[i++] = do_write;
 				// determine if it is in the range of actively written pages
 				if (freelist_written_start <= end && freelist_written_end >= start) {
 					// we will reserve one entry for size and potentially one extra entry in case we are splitting an entry
 					data.mv_size = (len + (head_id < pglast ? 2 : 1)) * sizeof(pgno_t);
+					if (txn->mt_loose_count > 0) {
+						fprintf(stderr, "Reserving freelist %u from %u-%u, size: %u, txn->mt_loose_count: %u, mop[0] %u\n", head_id, mop_len, end, data.mv_size, txn->mt_loose_count, mop[0]);
+					}
 					if (data.mv_size <= 0) {
 						sprintf(last_error, "attempt to reserve freelist had a data entry with zero-size, last len %i\n", len);
 						return MDB_BAD_TXN;
@@ -4303,9 +4306,14 @@ mdb_freelist_save(MDB_txn *txn)
 			mop[0] = 0;
 		}
 		mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
+		if (txn->mt_loose_count > 0) {
+			// loose pages are appended to the end, so we have to expand the range to the end
+			env->me_freelist_written_end = mop_len;
+			env->me_freelist_written_start = 1;
+		}
 		//fprintf(stderr, "mop_len %u = mop[0] %u + txn->mt_loose_count %u, reserved_sape,", mop_len, (mop ? mop[0] : 0), txn->mt_loose_count, reserved_space);
 		if (freelist_written_start != env->me_freelist_written_start)
-		freelist_written_end = env->me_freelist_written_end;
+			freelist_written_end = env->me_freelist_written_end;
 	} while(reserved_space != mop_len ||
 		 (start_written > env->me_freelist_start && env->me_freelist_start > 0) ||
 		 freecnt < txn->mt_free_pgs[0] ||
@@ -4317,8 +4325,10 @@ mdb_freelist_save(MDB_txn *txn)
 	 */
 	if (txn->mt_loose_pgs) {
 		MDB_page *mp = txn->mt_loose_pgs;
-		if (!env->me_pghead) env->me_pghead = mdb_midl_alloc(1);
+		if (!env->me_pghead)
+			env->me_pghead = mdb_midl_alloc(1);
 		unsigned count = txn->mt_loose_count;
+		fprintf(stderr, "Returning %u loose pages to me_pghead\n", count);
 		lost_loose += count;
 		for (; mp; mp = NEXT_LOOSE_PAGE(mp))
 			mdb_midl_append(&env->me_pghead, mp->mp_pgno);