Bug #31305 myisam tables crash when they are near capacity.

When we insert a record into MYISAM table which is almost 'full',
we first write record data in the free space inside a file, and then
check if we have enough space after the end of the file.
So if we don't have the space, table will left corrupted.
Similar error also happens when we updata MYISAM tables.

Fixed by modifying write_dynamic_record and update_dynamic_record functions
to check for free space before writing parts of a record


BitKeeper/etc/ignore:
  Added libmysql_r/client_settings.h libmysqld/ha_blackhole.cc to the ignore list
myisam/mi_dynrec.c:
  Bug #31305 myisam tables crash when they are near capacity.
  
  now we check space left in table in write_dynamic_record
  and update_dynamic_record functions.
  If we don't have enough room for the new (updated) record, return with the
  error.
mysql-test/r/almost_full.result:
  New BitKeeper file ``mysql-test/r/almost_full.result''
mysql-test/t/almost_full.test:
  New BitKeeper file ``mysql-test/t/almost_full.test''

1 files changed, 41 insertions, 0 deletions

diff --git a/mysql-test/t/almost_full.test b/mysql-test/t/almost_full.test
new file mode 100644
index 00000000000..5c67ab3c088
--- /dev/null
+++ b/mysql-test/t/almost_full.test
@@ -0,0 +1,41 @@
+#
+# Some special cases with empty tables
+#
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+set global myisam_data_pointer_size=2;
+CREATE TABLE t1 (a int auto_increment primary key not null, b longtext) ENGINE=MyISAM;
+
+--disable_query_log
+let $1= 303;
+while ($1)
+{
+  INSERT INTO t1 SET b=repeat('a',200);
+  dec $1;
+}
+--enable_query_log
+
+DELETE FROM t1 WHERE a=1 or a=5;
+
+--error 1114
+INSERT INTO t1 SET b=repeat('a',600);
+CHECK TABLE t1 EXTENDED;
+
+--error 1114
+UPDATE t1 SET b=repeat('a', 800) where a=10;
+CHECK TABLE t1 EXTENDED;
+
+INSERT INTO t1 SET b=repeat('a',400);
+CHECK TABLE t1 EXTENDED;
+
+DELETE FROM t1 WHERE a=2 or a=6;
+UPDATE t1 SET b=repeat('a', 600) where a=11;
+CHECK TABLE t1 EXTENDED;
+drop table t1;
+
+set global myisam_data_pointer_size=default;
+
+# End of 4.1 tests