From: drh <drh@noemail.net>
Date: Fri, 29 Jan 2010 21:23:35 +0000 (+0000)
Subject: Fix a missing mutex on page cache truncation during vacuum and auto-vacuum
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=10f1b20a69950e699a7f8ed756f298c65b69b66d;p=thirdparty%2Fsqlite.git

Fix a missing mutex on page cache truncation during vacuum and auto-vacuum
when SQLITE_ENABLE_MEMORY_MANAGEMENT is engaged.

FossilOrigin-Name: ea3b941a7182851117fab9851e98e175ebb356e2
---

diff --git a/manifest b/manifest
index 66ecdfc09e..a5dbb16448 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,8 @@
-C Version\s3.5.9\s(CVS\s5131)
-D 2008-05-14T16:18:11
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
+C Fix\sa\smissing\smutex\son\spage\scache\struncation\sduring\svacuum\sand\sauto-vacuum\s\nwhen\sSQLITE_ENABLE_MEMORY_MANAGEMENT\sis\sengaged.
+D 2010-01-29T21:23:35
 F Makefile.arm-wince-mingw32ce-gcc ac5f7b2cef0cd850d6f755ba6ee4ab961b1fadf7
 F Makefile.in 79aeba12300a54903f1b1257c1e7c190234045dd
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -121,7 +124,7 @@ F src/os_common.h e8b748b2f2ecc8a498e50bfe5d8721f189c19d2a
 F src/os_os2.c 0c3a5802bc4fdb7cb5f66771552b081c4e48a216
 F src/os_unix.c a810e2aefdaddacf479407f76f8f4ca381d231b2
 F src/os_win.c 3a60bddd07ea6f8adb2314dd5996ac97b988f403
-F src/pager.c 2607309c4848bfb8a5766d94d74157b54a44c6c0
+F src/pager.c 38743db63f91064ed68dba0b415cccf603be036a
 F src/pager.h 4f051fd856de6fd3c19aef5f82eace54122b9173
 F src/parse.y fc4bd35c6088901f7c8daead26c6fb11c87d22e7
 F src/pragma.c 2e4bb2e76e48a32750529fdc4bfe86ac5f54e01b
@@ -634,7 +637,18 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P e4aab150042bd22868ab02645151cb69a1c02ba0
-R c25ac8c50b83839e3cddbf23a801f9cb
+P b6129f4cc28f6ba55d19039545555b33857ffd72
+R 298ea4553820c86bc49de9db5217cdcf
+T *bgcolor * #8696fe
+T *branch * branch-3.5.9
+T *sym-branch-3.5.9 *
+T -sym-trunk *
 U drh
-Z 5d9759a5b998826f7607e53c2a3b8fed
+Z bc97c693bc947a5ae3e3ed014689d2e7
+-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1.4.6 (GNU/Linux)
+
+iD8DBQFLY1HaoxKgR168RlERAoniAJwOUHTFrCPOA7r6/18Q/Dp5vxUEAwCdGNnZ
+0OTkC0QU7xRU5btnXdQ92nY=
+=Y3Su
+-----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index b6a07d33f1..d56c3d99d5 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-b6129f4cc28f6ba55d19039545555b33857ffd72
\ No newline at end of file
+ea3b941a7182851117fab9851e98e175ebb356e2
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index a8d7b4200e..f89101e3a6 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -403,6 +403,7 @@ struct Pager {
   Pager *pPrev;               /* sqlite3_release_memory() will work */
   int iInUseMM;               /* Non-zero if unavailable to MM */
   int iInUseDB;               /* Non-zero if in sqlite3_release_memory() */
+  u8 onPagerList;             /* True if part of the sqlite3PagerList */
 #endif
   char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
   char dbFileVers[16];        /* Changes whenever database file changes */
@@ -511,6 +512,10 @@ static const unsigned char aJournalMagic[] = {
 ** function.  It does not prevent, for example, two Btrees from accessing
 ** the same pager at the same time.  Other general-purpose mutexes in
 ** the btree layer handle that chore.
+**
+** The pagerMutexHeld(X) macro is for sanity checking.  This macro verifies
+** that the database-connection mutex is held for pager X and asserts if it
+** is not.
 */
 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
   static void pagerEnter(Pager *p){
@@ -531,9 +536,11 @@ static const unsigned char aJournalMagic[] = {
     p->iInUseDB--;
     assert( p->iInUseDB>=0 );
   }
+# define pagerMutexHeld(X)  assert( (X)->iInUseDB>0 || !(X)->onPagerList )
 #else
 # define pagerEnter(X)
 # define pagerLeave(X)
+# define pagerMutexHeld(X)
 #endif
 
 /*
@@ -1273,6 +1280,7 @@ static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
 static void pager_reset(Pager *pPager){
   PgHdr *pPg, *pNext;
   if( pPager->errCode ) return;
+  pagerMutexHeld(pPager);
   for(pPg=pPager->pAll; pPg; pPg=pNext){
     IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
     PAGER_INCR(sqlite3_pager_pgfree_count);
@@ -2373,6 +2381,7 @@ int sqlite3PagerOpen(
     }
     pPager->pPrev = 0;
     sqlite3PagerList = pPager;
+    pPager->onPagerList = 1;
     sqlite3_mutex_leave(mutex);
   }
 #endif
@@ -2637,6 +2646,7 @@ static void pager_truncate_cache(Pager *pPager){
   PgHdr **ppPg;
   int dbSize = pPager->dbSize;
 
+  pagerMutexHeld(pPager);
   ppPg = &pPager->pAll;
   while( (pPg = *ppPg)!=0 ){
     if( pPg->pgno<=dbSize ){
@@ -2707,7 +2717,9 @@ int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
   }
   if( MEMDB ){
     pPager->dbSize = nPage;
+    pagerEnter(pPager);
     pager_truncate_cache(pPager);
+    pagerLeave(pPager);
     return SQLITE_OK;
   }
   pagerEnter(pPager);
@@ -2720,12 +2732,10 @@ int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
   /* Get an exclusive lock on the database before truncating. */
   pagerEnter(pPager);
   rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
-  pagerLeave(pPager);
-  if( rc!=SQLITE_OK ){
-    return rc;
+  if( rc==SQLITE_OK ){
+    rc = pager_truncate(pPager, nPage);
   }
-
-  rc = pager_truncate(pPager, nPage);
+  pagerLeave(pPager);
   return rc;
 }
 
@@ -2759,6 +2769,7 @@ int sqlite3PagerClose(Pager *pPager){
       pPager->pNext->pPrev = pPager->pPrev;
     }
     sqlite3_mutex_leave(mutex);
+    pPager->onPagerList = 0;
   }
 #endif