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Avoid writing the 8-byte journal-header magic until the journal-header is synced. In persistent journal-mode, this prevents any old content that follows an unsynced journal-header from being interpreted as part of the rollback journal. (CVS 6817)

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FossilOrigin-Name: a5ecffcf025da2fcb241e83c7bebc1095a3b51d6
This commit is contained in:
danielk1977
2009-06-26 07:12:06 +00:00
parent 46aa38f2c0
commit 6f4c73eedb
5 changed files with 48 additions and 23 deletions
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32
src/pager.c
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@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.601 2009/06/22 05:43:24 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.602 2009/06/26 07:12:07 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -757,7 +757,6 @@ static int writeJournalHdr(Pager *pPager){
}
pPager->journalHdr = pPager->journalOff = journalHdrOffset(pPager);
memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
/*
** Write the nRec Field - the number of page records that follow this
@@ -783,8 +782,10 @@ static int writeJournalHdr(Pager *pPager){
if( (pPager->noSync) || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
|| (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
){
memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
}else{
zHeader[0] = '\0';
put32bits(&zHeader[sizeof(aJournalMagic)], 0);
}
@@ -852,6 +853,7 @@ static int writeJournalHdr(Pager *pPager){
*/
static int readJournalHdr(
Pager *pPager, /* Pager object */
int isHot,
i64 journalSize, /* Size of the open journal file in bytes */
u32 *pNRec, /* OUT: Value read from the nRec field */
u32 *pDbSize /* OUT: Value of original database size field */
@@ -877,12 +879,14 @@ static int readJournalHdr(
** SQLITE_DONE. If an IO error occurs, return an error code. Otherwise,
** proceed.
*/
rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
if( rc ){
return rc;
}
if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
return SQLITE_DONE;
if( isHot || iHdrOff!=pPager->journalHdr ){
rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
if( rc ){
return rc;
}
if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
return SQLITE_DONE;
}
}
/* Read the first three 32-bit fields of the journal header: The nRec
@@ -1977,7 +1981,7 @@ static int pager_playback(Pager *pPager, int isHot){
** it is corrupted, then a process must of failed while writing it.
** This indicates nothing more needs to be rolled back.
*/
rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
if( rc!=SQLITE_OK ){
if( rc==SQLITE_DONE ){
rc = SQLITE_OK;
@@ -2197,7 +2201,7 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
u32 ii; /* Loop counter */
u32 nJRec = 0; /* Number of Journal Records */
u32 dummy;
rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
rc = readJournalHdr(pPager, 0, szJ, &nJRec, &dummy);
assert( rc!=SQLITE_DONE );
/*
@@ -2764,7 +2768,9 @@ static int syncJournal(Pager *pPager){
** of the nRec field of the most recently written journal header.
** This field will be updated following the xSync() operation
** on the journal file. */
i64 iNRecOffset = pPager->journalHdr + sizeof(aJournalMagic);
u8 zHeader[sizeof(aJournalMagic)+4];
memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
put32bits(&zHeader[sizeof(aJournalMagic)], pPager->nRec);
/* This block deals with an obscure problem. If the last connection
** that wrote to this database was operating in persistent-journal
@@ -2817,7 +2823,9 @@ static int syncJournal(Pager *pPager){
if( rc!=SQLITE_OK ) return rc;
}
IOTRACE(("JHDR %p %lld %d\n", pPager, iNRecOffset, 4));
rc = write32bits(pPager->jfd, iNRecOffset, pPager->nRec);
rc = sqlite3OsWrite(
pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
);
if( rc!=SQLITE_OK ) return rc;
}
if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){