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Pager changes attempting to verify that ticket #2565 cannot recur. (CVS 6126)

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FossilOrigin-Name: 15b9dac455b3f457bb177fc4985b45957647cbec
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drh
2009-01-07 02:03:35 +00:00
parent 5093f6e5ee
commit d6e5e09816
3 changed files with 139 additions and 40 deletions
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165
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 1.534 2009/01/06 15:58:57 drh Exp $
** @(#) $Id: pager.c,v 1.535 2009/01/07 02:03:35 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -734,8 +734,9 @@ static int writeJournalHdr(Pager *pPager){
/*
** The journal file must be open when this is called. A journal header file
** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
** file. See comments above function writeJournalHdr() for a description of
** the journal header format.
** file. The current location in the journal file is given by
** pPager->journalOff. See comments above function writeJournalHdr() for
** a description of the journal header format.
**
** If the header is read successfully, *nRec is set to the number of
** page records following this header and *dbSize is set to the size of the
@@ -744,7 +745,7 @@ static int writeJournalHdr(Pager *pPager){
** in this case.
**
** If the journal header file appears to be corrupted, SQLITE_DONE is
** returned and *nRec and *dbSize are not set. If JOURNAL_HDR_SZ bytes
** returned and *nRec and *dbSize are undefined. If JOURNAL_HDR_SZ bytes
** cannot be read from the journal file an error code is returned.
*/
static int readJournalHdr(
@@ -1124,17 +1125,25 @@ static u32 pager_cksum(Pager *pPager, const u8 *aData){
}
/*
** Read a single page from the journal file opened on file descriptor
** jfd. Playback this one page.
** Read a single page from either the journal file (if isMainJrnl==1) or
** from the sub-journal (if isMainJrnl==0) and playback that page.
** The page begins at offset *pOffset into the file. The *pOffset
** value is increased to the start of the next page in the journal.
**
** The isMainJrnl flag is true if this is the main rollback journal and
** false for the statement journal. The main rollback journal uses
** checksums - the statement journal does not.
**
** If pDone is not NULL, then it is a record of pages that have already
** been played back. If the page at *pOffset has already been played back
** (if the corresponding pDone bit is set) then skip the playback.
** Make sure the pDone bit corresponding to the *pOffset page is set
** prior to returning.
*/
static int pager_playback_one_page(
Pager *pPager, /* The pager being played back */
int isMainJrnl, /* 1 -> main journal. 0 -> sub-journal. */
i64 offset, /* Offset of record to playback */
i64 *pOffset, /* Offset of record to playback */
int isSavepnt, /* True for a savepoint rollback */
Bitvec *pDone /* Bitvec of pages already played back */
){
@@ -1142,19 +1151,24 @@ static int pager_playback_one_page(
PgHdr *pPg; /* An existing page in the cache */
Pgno pgno; /* The page number of a page in journal */
u32 cksum; /* Checksum used for sanity checking */
u8 *aData = (u8 *)pPager->pTmpSpace; /* Temp storage for a page */
sqlite3_file *jfd = (isMainJrnl ? pPager->jfd : pPager->sjfd);
u8 *aData; /* Temporary storage for the page */
sqlite3_file *jfd; /* The file descriptor for the journal file */
/* The temp storage must be allocated at this point */
assert( aData );
assert( isMainJrnl || pDone );
assert( isSavepnt || pDone==0 );
assert( (isMainJrnl&~1)==0 ); /* isMainJrnl is 0 or 1 */
assert( (isSavepnt&~1)==0 ); /* isSavepnt is 0 or 1 */
assert( isMainJrnl || pDone ); /* pDone always used on sub-journals */
assert( isSavepnt || pDone==0 ); /* pDone never used on non-savepoint */
rc = read32bits(jfd, offset, &pgno);
aData = (u8*)pPager->pTmpSpace;
assert( aData ); /* Temp storage must have already been allocated */
jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
rc = read32bits(jfd, *pOffset, &pgno);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3OsRead(jfd, aData, pPager->pageSize, offset+4);
rc = sqlite3OsRead(jfd, aData, pPager->pageSize, (*pOffset)+4);
if( rc!=SQLITE_OK ) return rc;
pPager->journalOff += pPager->pageSize + 4 + (isMainJrnl?4:0);
*pOffset += pPager->pageSize + 4 + isMainJrnl*4;
/* Sanity checking on the page. This is more important that I originally
** thought. If a power failure occurs while the journal is being written,
@@ -1168,7 +1182,7 @@ static int pager_playback_one_page(
return SQLITE_OK;
}
if( isMainJrnl ){
rc = read32bits(jfd, offset+pPager->pageSize+4, &cksum);
rc = read32bits(jfd, (*pOffset)-4, &cksum);
if( rc ) return rc;
if( !isSavepnt && pager_cksum(pPager, aData)!=cksum ){
return SQLITE_DONE;
@@ -1300,6 +1314,46 @@ static int pager_playback_one_page(
return rc;
}
#if /* !defined(NDEBUG) || */ defined(SQLITE_COVERAGE_TEST)
/*
** This routine looks ahead into the main journal file and determines
** whether or not the next record (the record that begins at file
** offset pPager->journalOff) is a well-formed page record consisting
** of a valid page number, pPage->pageSize bytes of content, followed
** by a valid checksum.
**
** The pager never needs to know this in order to do its job. This
** routine is only used from with assert() and testcase() macros.
*/
static int pagerNextJournalPageIsValid(Pager *pPager){
Pgno pgno; /* The page number of the page */
u32 cksum; /* The page checksum */
int rc; /* Return code from read operations */
sqlite3_file *fd; /* The file descriptor from which we are reading */
u8 *aData; /* Content of the page */
/* Read the page number header */
fd = pPager->jfd;
rc = read32bits(fd, pPager->journalOff, &pgno);
if( rc!=SQLITE_OK ){ return 0; } /*NO_TEST*/
if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){ return 0; } /*NO_TEST*/
if( pgno>(Pgno)pPager->dbSize ){ return 0; } /*NO_TEST*/
/* Read the checksum */
rc = read32bits(fd, pPager->journalOff+pPager->pageSize+4, &cksum);
if( rc!=SQLITE_OK ){ return 0; } /*NO_TEST*/
/* Read the data and verify the checksum */
aData = (u8*)pPager->pTmpSpace;
rc = sqlite3OsRead(fd, aData, pPager->pageSize, pPager->journalOff+4);
if( rc!=SQLITE_OK ){ return 0; } /*NO_TEST*/
if( pager_cksum(pPager, aData)!=cksum ){ return 0; } /*NO_TEST*/
/* Reach this point only if the page is valid */
return 1;
}
#endif /* !defined(NDEBUG) || defined(SQLITE_COVERAGE_TEST) */
/*
** Parameter zMaster is the name of a master journal file. A single journal
** file that referred to the master journal file has just been rolled back.
@@ -1589,7 +1643,18 @@ static int pager_playback(Pager *pPager, int isHot){
** size of the file.
**
** The third term of the test was added to fix ticket #2565.
** When rolling back a hot journal, nRec==0 always means that the next
** chunk of the journal contains zero pages to be rolled back. But
** when doing a ROLLBACK and the nRec==0 chunk is the last chunk in
** the journal, it means that the journal might contain additional
** pages that need to be rolled back and that the number of pages
** should be computed based on the journal file size.
*/
testcase( nRec==0 && !isHot
&& pPager->journalHdr+JOURNAL_HDR_SZ(pPager)!=pPager->journalOff
&& ((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager))>0
&& pagerNextJournalPageIsValid(pPager)
);
if( nRec==0 && !isHot &&
pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
nRec = (int)((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager));
@@ -1608,7 +1673,7 @@ static int pager_playback(Pager *pPager, int isHot){
/* Copy original pages out of the journal and back into the database file.
*/
for(u=0; u<nRec; u++){
rc = pager_playback_one_page(pPager, 1, pPager->journalOff, 0, 0);
rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 0, 0);
if( rc!=SQLITE_OK ){
if( rc==SQLITE_DONE ){
rc = SQLITE_OK;
@@ -1652,10 +1717,14 @@ end_playback:
}
/*
** Playback a savepoint.
** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
** the entire master journal file.
**
** The case pSavepoint==NULL occurs when a ROLLBACK TO command is invoked
** on a SAVEPOINT that is a transaction savepoint.
*/
static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
i64 szJ; /* Size of the full journal */
i64 szJ; /* Effective size of the main journal */
i64 iHdrOff; /* End of first segment of main-journal records */
Pgno ii; /* Loop counter */
int rc = SQLITE_OK; /* Return code */
@@ -1672,46 +1741,76 @@ static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
/* Truncate the database back to the size it was before the
** savepoint being reverted was opened.
*/
pPager->dbSize = pSavepoint?pSavepoint->nOrig:pPager->dbOrigSize;
pPager->dbSize = pSavepoint ? pSavepoint->nOrig : pPager->dbOrigSize;
assert( pPager->state>=PAGER_SHARED );
/* Now roll back all main journal file records that occur after byte
** byte offset PagerSavepoint.iOffset that have a page number less than
** or equal to PagerSavepoint.nOrig. As each record is played back,
** the corresponding bit in bitvec PagerSavepoint.pInSavepoint is
** cleared.
/* Use pPager->journalOff as the effective size of the main rollback
** journal. The actual file might be larger than this in
** PAGER_JOURNALMODE_TRUNCATE or PAGER_JOURNALMODE_PERSIST. But anything
** past pPager->journalOff is off-limits to us.
*/
szJ = pPager->journalOff;
/* Begin by rolling back records from the main journal starting at
** PagerSavepoint.iOffset and continuing to the next journal header.
** There might be records in the main journal that have a page number
** greater than the current database size (pPager->dbSize) but those
** will be skipped automatically. Pages are added to pDone as they
** are played back.
*/
if( pSavepoint ){
iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;
pPager->journalOff = pSavepoint->iOffset;
while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
rc = pager_playback_one_page(pPager, 1, pPager->journalOff, 1, pDone);
rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 1, pDone);
assert( rc!=SQLITE_DONE );
}
}else{
pPager->journalOff = 0;
}
/* Continue rolling back records out of the main journal starting at
** the first journal header seen and continuing until the effective end
** of the main journal file. Continue to skip out-of-range pages and
** continue adding pages rolled back to pDone.
*/
while( rc==SQLITE_OK && pPager->journalOff<szJ ){
u32 nJRec = 0; /* Number of Journal Records */
u32 dummy;
rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
assert( rc!=SQLITE_DONE );
if( nJRec==0 ){
nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
/*
** The "pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff"
** test is related to ticket #2565. See the discussion in the
** pager_playback() function for additional information.
*/
testcase( nJRec==0
&& pPager->journalHdr+JOURNAL_HDR_SZ(pPager)!=pPager->journalOff
&& ((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager))>0
&& pagerNextJournalPageIsValid(pPager)
);
if( nJRec==0
&& pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff
){
nJRec = (szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager);
}
for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
rc = pager_playback_one_page(pPager, 1, pPager->journalOff, 1, pDone);
rc = pager_playback_one_page(pPager, 1, &pPager->journalOff, 1, pDone);
assert( rc!=SQLITE_DONE );
}
}
assert( rc!=SQLITE_OK || pPager->journalOff==szJ );
/* Now roll back pages from the sub-journal. */
/* Finally, rollback pages from the sub-journal. Page that were
** previously rolled back out of the main journal (and are hence in pDone)
** will be skipped. Out-of-range pages are also skipped.
*/
if( pSavepoint ){
i64 offset = pSavepoint->iSubRec*(4+pPager->pageSize);
for(ii=pSavepoint->iSubRec; rc==SQLITE_OK&&ii<(u32)pPager->stmtNRec; ii++){
i64 offset = ii*(4+pPager->pageSize);
rc = pager_playback_one_page(pPager, 0, offset, 1, pDone);
assert( offset == ii*(4+pPager->pageSize) );
rc = pager_playback_one_page(pPager, 0, &offset, 1, pDone);
assert( rc!=SQLITE_DONE );
}
}