MDEV-24695 Encryption modifies a freed page

During recovery, InnoDB fails if it tries to apply a FREE_PAGE
and WRITE record to the page. InnoDB encryption thread accesses
the freed page and writes redo log for it.

This is similar to commit deadec4e68 (MDEV-24569)
InnoDB is missing buf_page_free() while freeing the segment.
To avoid accessing of freed page in buffer pool, InnoDB should
mark the pages as FREED while freeing the segment. Also to
avoid reading of freed page, InnoDB should check the
allocation bitmap page.

fseg_free_step(): Mark the page in buffer pool as FREED

fseg_free_step_not_header(): Mark the page in buffer pool as FREED

buf_dump(): Ignore the freed pages while dumping the buffer pool content

fil_crypt_get_page_throttle_func(): Skip the rotation for FREED page
to avoid the assert failure during recovery

fil_crypt_rotate_page(): Skip the rotation for the freed page

Reviewed-by: Marko Mäkelä

mysql-test/suite/encryption/t/innodb_encryption.test

@@ -14,7 +14,7 @@ SHOW VARIABLES LIKE 'innodb_encrypt%';
 
 SET GLOBAL innodb_encrypt_tables = ON;
 
---let $tables_count= `select count(*) + 1 from information_schema.tables where engine = 'InnoDB'`
+--let $tables_count= `select count(*) + @@global.innodb_undo_tablespaces + 1 from information_schema.tables where engine = 'InnoDB'`
 
 --echo # Wait max 10 min for key encryption threads to encrypt all spaces
 --let $wait_timeout= 600