Additional changes in the pager and os interface layers to fix problems that

might be contributing to recently observed database corruption. (CVS 3549)

FossilOrigin-Name: a593d5743eab12c0f93a7bc436f0d69dfab0c387

manifest

@@ -1,5 +1,5 @@
-C Make\ssure\sthat\sthe\sdatabase\ssize\scache\sin\sthe\spager\sis\sinvalidated\swhenever\nthe\sdatabase\sis\sunlocked.\s\sA\sstale\svalue\sin\sthe\sdatabase\ssize\scache\scan\nresult\sin\sdatabase\scorruption\son\sa\sheavily\sloaded\ssystem\srunning\nautovacuum.\s(CVS\s3548)
+C Additional\schanges\sin\sthe\spager\sand\sos\sinterface\slayers\sto\sfix\sproblems\sthat\nmight\sbe\scontributing\sto\srecently\sobserved\sdatabase\scorruption.\s(CVS\s3549)
-D 2007-01-03T15:34:30
+D 2007-01-03T23:36:22
 F Makefile.in 63a71177ed4355c829229affe11167bd28c85884
 F Makefile.linux-gcc 2d8574d1ba75f129aba2019f0b959db380a90935
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -81,11 +81,11 @@ F src/os_os2.c 1ece434c4817e2925318954336cfe1731713beb0
 F src/os_os2.h e5f17dd69333632bbc3112881ea407c37d245eb3
 F src/os_test.c 49833426101f99aee4bb5f6a44b7c4b2029fda1c
 F src/os_test.h 903c93554c23d88f34f667f1979e4a1cee792af3
-F src/os_unix.c d4bc8cbe1c0dc330bd55bf7821db5b7dbfbf183e
+F src/os_unix.c 9fbbd8ab0a6b3992370ba0f3aae11feff2a78c96
 F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
-F src/os_win.c ca46001d4ec446885f72d3b7fd6a657136156228
+F src/os_win.c 92df146ed964401969831a19bb490d76ce4de4c0
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c 4dbd6a12eb43f10a3c870a3006a54a7756768455
+F src/pager.c 28fdd84dc1f6eaa2ea0754bc88f7e0efd74b9eb9
 F src/pager.h 2e6d42f4ae004ae748a037b8468112b851c447a7
 F src/parse.y 2f571c5f6219428d7fb08737db3d113742b1cceb
 F src/pragma.c d0891d3504b6291b506a5ec2226bbf79ffcef003
@@ -423,7 +423,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
-P bf1afd016ad71dac90e58540122108f92e77ce3d
+P 6806b9ecb5e3b90e793c5862404e76485df33b25
-R ffed07664ab99ec35d86454afb31b5e4
+R 5eb75b3bfe211ed1d7c750440df7692b
 U drh
-Z 6c9f735d21716c225946d83bfcb229d4
+Z bcb83f017e9e848c1a261f1dbdf86d77

manifest.uuid

@@ -1 +1 @@
-6806b9ecb5e3b90e793c5862404e76485df33b25
+a593d5743eab12c0f93a7bc436f0d69dfab0c387

src/os_unix.c

@@ -1032,6 +1032,7 @@ static int unixRead(OsFile *id, void *pBuf, int amt){
   }else if( got<0 ){
     return SQLITE_IOERR_READ;
   }else{
+    memset(&((char*)pBuf)[got], 0, amt-got);
     return SQLITE_IOERR_SHORT_READ;
   }
 }

src/os_win.c

@@ -1010,6 +1010,7 @@ static int winRead(OsFile *id, void *pBuf, int amt){
   }else if( got<0 ){
     return SQLITE_IOERR_READ;
   }else{
+    memset(&((char*)pBuf)[got], 0, amt-got);
     return SQLITE_IOERR_SHORT_READ;
   }
 }

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.279 2007/01/03 15:34:30 drh Exp $
+** @(#) $Id: pager.c,v 1.280 2007/01/03 23:36:22 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -863,6 +863,7 @@ static void pager_unlock(Pager *pPager){
     pPager->dbSize = -1;
   }
   pPager->state = PAGER_UNLOCK;
+  assert( pPager->pAll==0 );
 }
 
 
@@ -892,7 +893,7 @@ static void pager_reset(Pager *pPager){
   }
   pager_unlock(pPager);
   pPager->nRef = 0;
-  assert( pPager->journalOpen==0 );
+  assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
 }
 
 /*
@@ -2063,7 +2064,6 @@ int sqlite3pager_truncate(Pager *pPager, Pgno nPage){
 ** to the caller.
 */
 int sqlite3pager_close(Pager *pPager){
-  PgHdr *pPg, *pNext;
 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
   /* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to 
   ** malloc() must have already been made by this thread before it gets
@@ -2075,42 +2075,9 @@ int sqlite3pager_close(Pager *pPager){
   assert( pTsd && pTsd->nAlloc );
 #endif
 
-  switch( pPager->state ){
+  disable_simulated_io_errors();
-    case PAGER_RESERVED:
+  pager_reset(pPager);
-    case PAGER_SYNCED: 
+  enable_simulated_io_errors();
-    case PAGER_EXCLUSIVE: {
-      /* We ignore any IO errors that occur during the rollback
-      ** operation. So disable IO error simulation so that testing
-      ** works more easily.
-      */
-      disable_simulated_io_errors();
-      sqlite3pager_rollback(pPager);
-      enable_simulated_io_errors();
-      pager_unlock(pPager);
-      assert( pPager->errCode || pPager->journalOpen==0 );
-      break;
-    }
-    case PAGER_SHARED: {
-      pager_unlock(pPager);
-      break;
-    }
-    default: {
-      /* Do nothing */
-      break;
-    }
-  }
-  for(pPg=pPager->pAll; pPg; pPg=pNext){
-#ifndef NDEBUG
-    if( MEMDB ){
-      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
-      assert( !pPg->alwaysRollback );
-      assert( !pHist->pOrig );
-      assert( !pHist->pStmt );
-    }
-#endif
-    pNext = pPg->pNextAll;
-    sqliteFree(pPg);
-  }
   TRACE2("CLOSE %d\n", PAGERID(pPager));
   assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
   if( pPager->journalOpen ){
@@ -2989,7 +2956,7 @@ failed_to_open_journal:
     */
     sqlite3OsDelete(pPager->zJournal);
   }else{
-    pager_unlock(pPager);
+    pager_reset(pPager);
   }
   return rc;
 }