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/** @file include/buf0flu.ic
 The database buffer pool flush algorithm

 Created 11/5/1995 Heikki Tuuri
 *******************************************************/

#include "buf0buf.h"
#include "fsp0types.h"
#include "mtr0mtr.h"
#include "srv0srv.h"

#ifndef UNIV_HOTBACKUP
/** Inserts a modified block into the flush list. */
void buf_flush_insert_into_flush_list(
    buf_pool_t *buf_pool, /*!< buffer pool instance */
    buf_block_t *block,   /*!< in/out: block which is modified */
    lsn_t lsn);           /*!< in: oldest modification */

/** Inserts a modified block into the flush list in the right sorted position.
 This function is used by recovery, because there the modifications do not
 necessarily come in the order of lsn's. */
void buf_flush_insert_sorted_into_flush_list(
    buf_pool_t *buf_pool, /*!< buffer pool instance */
    buf_block_t *block,   /*!< in/out: block which is modified */
    lsn_t lsn);           /*!< in: oldest modification */

/** This function should be called at a mini-transaction commit, if a page was
 modified in it. Puts the block to the list of modified blocks, if it is not
 already in it. */
UNIV_INLINE
void buf_flush_note_modification(
    buf_block_t *block,      /*!< in: block which is modified */
    lsn_t start_lsn,         /*!< in: start lsn of the mtr that
                             modified this block */
    lsn_t end_lsn,           /*!< in: end lsn of the mtr that
                             modified this block */
    FlushObserver *observer) /*!< in: flush observer */
{
#ifdef UNIV_DEBUG
  {
    /* Allow write to proceed to shared temporary tablespace
    in read-only mode. */
    ut_ad(!srv_read_only_mode ||
          fsp_is_system_temporary(block->page.id.space()));
    ut_ad(buf_block_get_state(block) == BUF_BLOCK_FILE_PAGE);
    ut_ad(block->page.buf_fix_count > 0);

    buf_pool_t *buf_pool = buf_pool_from_block(block);

    ut_ad(!buf_flush_list_mutex_own(buf_pool));
  }
#endif /* UNIV_DEBUG */

  lizard::page_write_req_stat(block);

  mutex_enter(&block->mutex);

  if (end_lsn != 0) {
    ut_ad(block->page.newest_modification <= end_lsn);
    block->page.newest_modification = end_lsn;
  } else {
    /* Do nothing. This is the case with no-redo mtr and it
    possibly could re-modify some earlier dirtied page, in
    which case we don't want to change oldest/newest lsns.
    If that's not the case, we will set newest_modification
    within buf_flush_insert_into_flush_list call. That's
    because we can't read the value now, because we don't
    hold the flush list mutex yet. */
  }

  /* Don't allow to set flush observer from non-null to null,
  or from one observer to another. */
  ut_ad(block->page.flush_observer == NULL ||
        block->page.flush_observer == observer);
  block->page.flush_observer = observer;

  if (block->page.oldest_modification == 0) {
    buf_pool_t *buf_pool = buf_pool_from_block(block);

    buf_flush_insert_into_flush_list(buf_pool, block, start_lsn);
  } else if (start_lsn != 0) {
    ut_ad(block->page.oldest_modification <= start_lsn);
  }

  buf_page_mutex_exit(block);

  srv_stats.buf_pool_write_requests.inc();
}

/** This function should be called when recovery has modified a buffer page. */
UNIV_INLINE
void buf_flush_recv_note_modification(
    buf_block_t *block, /*!< in: block which is modified */
    lsn_t start_lsn,    /*!< in: start lsn of the first mtr in a
                        set of mtr's */
    lsn_t end_lsn)      /*!< in: end lsn of the last mtr in the
                        set of mtr's */
{
#ifdef UNIV_DEBUG
  {
    ut_ad(!srv_read_only_mode);
    ut_ad(buf_block_get_state(block) == BUF_BLOCK_FILE_PAGE);
    ut_ad(block->page.buf_fix_count > 0);

    buf_pool_t *buf_pool = buf_pool_from_block(block);

    ut_ad(!buf_flush_list_mutex_own(buf_pool));

    ut_ad(start_lsn != 0);
    ut_ad(block->page.newest_modification <= end_lsn);
  }
#endif /* UNIV_DEBUG */

  buf_page_mutex_enter(block);

  block->page.newest_modification = end_lsn;

  if (!block->page.oldest_modification) {
    buf_pool_t *buf_pool = buf_pool_from_block(block);

    buf_flush_insert_sorted_into_flush_list(buf_pool, block, start_lsn);
  } else {
    ut_ad(block->page.oldest_modification <= start_lsn);
  }

  buf_page_mutex_exit(block);
}
#endif /* !UNIV_HOTBACKUP */