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diff --git a/storage/innobase/include/buf0dblwr.h b/storage/innobase/include/buf0dblwr.h
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+++ b/storage/innobase/include/buf0dblwr.h
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+/*****************************************************************************
+
+Copyright (c) 1995, 2011, Oracle and/or its affiliates. All Rights Reserved.
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+/**************************************************//**
+@file include/buf0dblwr.h
+Doublewrite buffer module
+
+Created 2011/12/19 Inaam Rana
+*******************************************************/
+
+#ifndef buf0dblwr_h
+#define buf0dblwr_h
+
+#include "univ.i"
+#include "ut0byte.h"
+#include "log0log.h"
+#include "buf0types.h"
+
+#ifndef UNIV_HOTBACKUP
+
+/** Doublewrite system */
+extern buf_dblwr_t*	buf_dblwr;
+/** Set to TRUE when the doublewrite buffer is being created */
+extern ibool		buf_dblwr_being_created;
+
+/****************************************************************//**
+Creates the doublewrite buffer to a new InnoDB installation. The header of the
+doublewrite buffer is placed on the trx system header page. */
+UNIV_INTERN
+void
+buf_dblwr_create(void);
+/*==================*/
+/****************************************************************//**
+At a database startup initializes the doublewrite buffer memory structure if
+we already have a doublewrite buffer created in the data files. If we are
+upgrading to an InnoDB version which supports multiple tablespaces, then this
+function performs the necessary update operations. If we are in a crash
+recovery, this function uses a possible doublewrite buffer to restore
+half-written pages in the data files. */
+UNIV_INTERN
+void
+buf_dblwr_init_or_restore_pages(
+/*============================*/
+	ibool	restore_corrupt_pages);	/*!< in: TRUE=restore pages */
+/****************************************************************//**
+frees doublewrite buffer. */
+UNIV_INTERN
+void
+buf_dblwr_free(void);
+/*================*/
+/********************************************************************//**
+Updates the doublewrite buffer when an IO request that is part of an
+LRU or flush batch is completed. */
+UNIV_INTERN
+void
+buf_dblwr_update(void);
+/*==================*/
+/****************************************************************//**
+Determines if a page number is located inside the doublewrite buffer.
+@return TRUE if the location is inside the two blocks of the
+doublewrite buffer */
+UNIV_INTERN
+ibool
+buf_dblwr_page_inside(
+/*==================*/
+	ulint	page_no);	/*!< in: page number */
+/********************************************************************//**
+Posts a buffer page for writing. If the doublewrite memory buffer is
+full, calls buf_dblwr_flush_buffered_writes and waits for for free
+space to appear. */
+UNIV_INTERN
+void
+buf_dblwr_add_to_batch(
+/*====================*/
+	buf_page_t*	bpage);	/*!< in: buffer block to write */
+/********************************************************************//**
+Flushes possible buffered writes from the doublewrite memory buffer to disk,
+and also wakes up the aio thread if simulated aio is used. It is very
+important to call this function after a batch of writes has been posted,
+and also when we may have to wait for a page latch! Otherwise a deadlock
+of threads can occur. */
+UNIV_INTERN
+void
+buf_dblwr_flush_buffered_writes(void);
+/*=================================*/
+/********************************************************************//**
+Writes a page to the doublewrite buffer on disk, sync it, then write
+the page to the datafile and sync the datafile. This function is used
+for single page flushes. If all the buffers allocated for single page
+flushes in the doublewrite buffer are in use we wait here for one to
+become free. We are guaranteed that a slot will become free because any
+thread that is using a slot must also release the slot before leaving
+this function. */
+UNIV_INTERN
+void
+buf_dblwr_write_single_page(
+/*========================*/
+	buf_page_t*	bpage);	/*!< in: buffer block to write */
+
+/** Doublewrite control struct */
+struct buf_dblwr_struct{
+	mutex_t	mutex;		/*!< mutex protecting the first_free field and
+				write_buf */
+	ulint	block1;		/*!< the page number of the first
+				doublewrite block (64 pages) */
+	ulint	block2;		/*!< page number of the second block */
+	ulint	first_free;	/*!< first free position in write_buf measured
+				in units of UNIV_PAGE_SIZE */
+	ulint	s_reserved;	/*!< number of slots currently reserved
+				for single page flushes. */
+	ulint	b_reserved;	/*!< number of slots currently reserved
+				for batch flush. */
+	ibool*	in_use;		/*!< flag used to indicate if a slot is
+				in use. Only used for single page
+				flushes. */
+	ibool	batch_running;	/*!< set to TRUE if currently a batch
+				is being written from the doublewrite
+				buffer. */
+	byte*	write_buf;	/*!< write buffer used in writing to the
+				doublewrite buffer, aligned to an
+				address divisible by UNIV_PAGE_SIZE
+				(which is required by Windows aio) */
+	byte*	write_buf_unaligned;
+				/*!< pointer to write_buf, but unaligned */
+	buf_page_t**
+		buf_block_arr;	/*!< array to store pointers to the buffer
+				blocks which have been cached to write_buf */
+};
+
+
+#endif /* UNIV_HOTBACKUP */
+
+#endif