** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.623 2009/07/25 15:24:14 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
static int pager_error(Pager *pPager, int rc){
  int rc2 = rc & 0xff;
  assert(
       pPager->errCode==SQLITE_FULL ||
       pPager->errCode==SQLITE_OK ||
       (pPager->errCode & 0xff)==SQLITE_IOERR
  );
  if(
    rc2==SQLITE_FULL ||
    rc2==SQLITE_IOERR ||
    rc2==SQLITE_CORRUPT
  ){
    pPager->errCode = rc;
    if( pPager->state==PAGER_UNLOCK 
     && sqlite3PcacheRefCount(pPager->pPCache)==0 
    ){
      /* If the pager is already unlocked, call pager_unlock() now to
      ** clear the error state and ensure that the pager-cache is 
      ** completely empty.
      */
      pager_unlock(pPager);
    }
  }
  return rc;
}

/*
** Execute a rollback if a transaction is active and unlock the 
** database file. 
................................................................................
  ** flag is set, return without doing anything. The pcache layer will
  ** just have to go ahead and allocate a new page buffer instead of
  ** reusing pPg.
  **
  ** Similarly, if the pager has already entered the error state, do not
  ** try to write the contents of pPg to disk.
  */

  if( pPager->errCode || (pPager->doNotSync && pPg->flags&PGHDR_NEED_SYNC) ){

    return SQLITE_OK;
  }

  /* Sync the journal file if required. */
  if( pPg->flags&PGHDR_NEED_SYNC ){
    rc = syncJournal(pPager);
    if( rc==SQLITE_OK && pPager->fullSync && 

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.624 2009/07/25 17:08:36 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
static int pager_error(Pager *pPager, int rc){
  int rc2 = rc & 0xff;
  assert(
       pPager->errCode==SQLITE_FULL ||
       pPager->errCode==SQLITE_OK ||
       (pPager->errCode & 0xff)==SQLITE_IOERR
  );

  if( rc2==SQLITE_FULL || rc2==SQLITE_IOERR ){



    pPager->errCode = rc;









  }
  return rc;
}

/*
** Execute a rollback if a transaction is active and unlock the 
** database file. 
................................................................................
  ** flag is set, return without doing anything. The pcache layer will
  ** just have to go ahead and allocate a new page buffer instead of
  ** reusing pPg.
  **
  ** Similarly, if the pager has already entered the error state, do not
  ** try to write the contents of pPg to disk.
  */
  if( NEVER(pPager->errCode)
   || (pPager->doNotSync && pPg->flags&PGHDR_NEED_SYNC)
  ){
    return SQLITE_OK;
  }

  /* Sync the journal file if required. */
  if( pPg->flags&PGHDR_NEED_SYNC ){
    rc = syncJournal(pPager);
    if( rc==SQLITE_OK && pPager->fullSync &&