From: drh <drh@noemail.net>
Date: Fri, 20 Mar 2009 13:15:30 +0000 (+0000)
Subject: Rename the unused MEM2 static mutex to OPEN and reuse it to serialize access
X-Git-Tag: version-3.6.15~387
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7555d8ec40616c89d4ae27527b8b90698cf6ec8b;p=thirdparty%2Fsqlite.git

Rename the unused MEM2 static mutex to OPEN and reuse it to serialize access
to the sqlite3BtreeOpen() routine to prevent a race condition on detection
of sharable caches.  Ticket #3735. (CVS 6363)

FossilOrigin-Name: 19fa5a29b97f017a9e176e48c848100299ba6920
---

diff --git a/manifest b/manifest
index 36b6563a1b..ecfcd0c706 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\sin\sthread005.test\scause\serrors\son\sosx.\s(CVS\s6362)
-D 2009-03-20T10:24:04
+C Rename\sthe\sunused\sMEM2\sstatic\smutex\sto\sOPEN\sand\sreuse\sit\sto\sserialize\saccess\nto\sthe\ssqlite3BtreeOpen()\sroutine\sto\sprevent\sa\srace\scondition\son\sdetection\nof\ssharable\scaches.\s\sTicket\s#3735.\s(CVS\s6363)
+D 2009-03-20T13:15:30
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -103,7 +103,7 @@ F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/backup.c 0082d0e5a63f04e88faee0dff0a7d63d3e92a78d
 F src/bitvec.c 44f7059ac1f874d364b34af31b9617e52223ba75
 F src/btmutex.c 341502bc496dc0840dcb00cde65680fb0e85c3ab
-F src/btree.c 081e1aac3ce4c79c5ed628a1fec533857d175eea
+F src/btree.c 4fbb5f26f450bee7356ec63cb664c8d733e28d89
 F src/btree.h e302c5747494067cd4f5763000fbe7bca767d816
 F src/btreeInt.h 17697718bb5281b12da5c65ecb0bffc45f2c0125
 F src/build.c c816377c118047418fda81edb8866b9c7a4e4031
@@ -157,7 +157,7 @@ F src/resolve.c 094e44450371fb27869eb8bf679aacbe51fdc56d
 F src/rowset.c ba9375f37053d422dd76965a9c370a13b6e1aac4
 F src/select.c 4d0b77fd76ff80f09a798ee98953e344c9de8fbb
 F src/shell.c 0a11f831603f17fea20ca97133c0f64e716af4a7
-F src/sqlite.h.in 0f756e9e8db9d491d0f17ea9c07952974975e43d
+F src/sqlite.h.in 0db1e59d89aeacb8fe64a19fd14c13a796060ccb
 F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
 F src/sqliteInt.h 250be86c98646e0d48436d6455b6fe916742bffa
 F src/sqliteLimit.h ffe93f5a0c4e7bd13e70cd7bf84cfb5c3465f45d
@@ -185,7 +185,7 @@ F src/test_journal.c 632011e420a581614343e78bc2fe77bd409a1706
 F src/test_loadext.c 97dc8800e46a46ed002c2968572656f37e9c0dd9
 F src/test_malloc.c d23050c7631ec9ee0369c7ca905e6c9233968e11
 F src/test_md5.c 032ae2bb6f81da350d2404e81fa8d560c8268026
-F src/test_mutex.c 87d99bdad7fb5d9aa4b5c7cf42423cfbf56eba2c
+F src/test_mutex.c 482d9d987c1c678199691efc23c8cd3464e01ff5
 F src/test_onefile.c 1efd91e63ce3d92e8331bfed83854e2b4dcd2e72
 F src/test_osinst.c 9a70a61e127f9e72bcfca000b20368b1c5367873
 F src/test_pcache.c 29464896d9c67832e4eef916c0682b98d7283d00
@@ -475,7 +475,7 @@ F test/misc5.test 6a5c1e3217a95b0db05ff9a0f1ecb5ce9043ffef
 F test/misc6.test 953cc693924d88e6117aeba16f46f0bf5abede91
 F test/misc7.test debcd7dbfd847ae97b16ceb7fec6f567902874a6
 F test/misuse.test 30b3a458e5a70c31e74c291937b6c82204c59f33
-F test/mutex1.test 1e5c196d5170bbe3a7d8370b1b905e8c86a9e07c
+F test/mutex1.test ace3ba551ef0cd864df2b820b5dbe18d28b4db6c
 F test/mutex2.test bfeaeac2e73095b2ac32285d2756e3a65e681660
 F test/nan.test c627d79b3d36ea892563fd67584b3e8a18f0618a
 F test/notify1.test 9a985a94f34de1b24daf25fd86b6d5033ba532d0
@@ -709,7 +709,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 18680989b5365b0e35fadca5919dfced22433ff4
-R 84c3a02fa54e49a7eceb26ef6ca40a97
-U danielk1977
-Z 7df2e0e297e433d337cbcfc3fa681e86
+P 56e6fca1a9da69c3a0fe43b00db9a6d9d93f03ba
+R e2b2822c930e07999a7faadbecce8455
+U drh
+Z 94771809e81ff193bb7785b130c75e1e
diff --git a/manifest.uuid b/manifest.uuid
index c25516de85..5d0835618f 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-56e6fca1a9da69c3a0fe43b00db9a6d9d93f03ba
\ No newline at end of file
+19fa5a29b97f017a9e176e48c848100299ba6920
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index 06e7536870..68d87aa1ea 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.575 2009/03/18 10:33:01 danielk1977 Exp $
+** $Id: btree.c,v 1.576 2009/03/20 13:15:30 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -42,6 +42,8 @@ int sqlite3BtreeTrace=0;  /* True to enable tracing */
 ** in shared cache.  This variable has file scope during normal builds,
 ** but the test harness needs to access it so we make it global for 
 ** test builds.
+**
+** Access to this variable is protected by SQLITE_MUTEX_STATIC_MASTER.
 */
 #ifdef SQLITE_TEST
 BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
@@ -1334,12 +1336,13 @@ int sqlite3BtreeOpen(
   int flags,              /* Options */
   int vfsFlags            /* Flags passed through to sqlite3_vfs.xOpen() */
 ){
-  sqlite3_vfs *pVfs;      /* The VFS to use for this btree */
-  BtShared *pBt = 0;      /* Shared part of btree structure */
-  Btree *p;               /* Handle to return */
-  int rc = SQLITE_OK;
-  u8 nReserve;
-  unsigned char zDbHeader[100];
+  sqlite3_vfs *pVfs;             /* The VFS to use for this btree */
+  BtShared *pBt = 0;             /* Shared part of btree structure */
+  Btree *p;                      /* Handle to return */
+  sqlite3_mutex *mutexOpen = 0;  /* Prevents a race condition. Ticket #3537 */
+  int rc = SQLITE_OK;            /* Result code from this function */
+  u8 nReserve;                   /* Byte of unused space on each page */
+  unsigned char zDbHeader[100];  /* Database header content */
 
   /* Set the variable isMemdb to true for an in-memory database, or 
   ** false for a file-based database. This symbol is only required if
@@ -1385,6 +1388,8 @@ int sqlite3BtreeOpen(
         return SQLITE_NOMEM;
       }
       sqlite3OsFullPathname(pVfs, zFilename, nFullPathname, zFullPathname);
+      mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
+      sqlite3_mutex_enter(mutexOpen);
       mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
       sqlite3_mutex_enter(mutexShared);
       for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){
@@ -1538,6 +1543,10 @@ btree_open_out:
     sqlite3_free(p);
     *ppBtree = 0;
   }
+  if( mutexOpen ){
+    assert( sqlite3_mutex_held(mutexOpen) );
+    sqlite3_mutex_leave(mutexOpen);
+  }
   return rc;
 }
 
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 96f577de4f..d8f51e79cd 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -30,7 +30,7 @@
 ** the version number) and changes its name to "sqlite3.h" as
 ** part of the build process.
 **
-** @(#) $Id: sqlite.h.in,v 1.435 2009/03/16 13:37:02 drh Exp $
+** @(#) $Id: sqlite.h.in,v 1.436 2009/03/20 13:15:30 drh Exp $
 */
 #ifndef _SQLITE3_H_
 #define _SQLITE3_H_
@@ -4726,7 +4726,8 @@ int sqlite3_mutex_notheld(sqlite3_mutex*);
 #define SQLITE_MUTEX_RECURSIVE        1
 #define SQLITE_MUTEX_STATIC_MASTER    2
 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
-#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
 #define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
diff --git a/src/test_mutex.c b/src/test_mutex.c
index 2d0f719a63..69030aedcc 100644
--- a/src/test_mutex.c
+++ b/src/test_mutex.c
@@ -10,7 +10,7 @@
 **
 *************************************************************************
 ** 
-** $Id: test_mutex.c,v 1.14 2009/02/11 05:18:07 danielk1977 Exp $
+** $Id: test_mutex.c,v 1.15 2009/03/20 13:15:30 drh Exp $
 */
 
 #include "tcl.h"
@@ -248,7 +248,7 @@ static int test_read_mutex_counters(
   int ii;
   char *aName[8] = {
     "fast",        "recursive",   "static_master", "static_mem", 
-    "static_mem2", "static_prng", "static_lru",    "static_lru2"
+    "static_open", "static_prng", "static_lru",    "static_lru2"
   };
 
   if( objc!=1 ){
diff --git a/test/mutex1.test b/test/mutex1.test
index 9e9da355b6..68bc69eb4c 100644
--- a/test/mutex1.test
+++ b/test/mutex1.test
@@ -9,7 +9,7 @@
 #
 #***********************************************************************
 #
-# $Id: mutex1.test,v 1.17 2009/01/09 14:29:35 drh Exp $
+# $Id: mutex1.test,v 1.18 2009/03/20 13:15:31 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -101,8 +101,8 @@ set enable_shared_cache [sqlite3_enable_shared_cache 1]
 ifcapable threadsafe {
   foreach {mode mutexes} {
     singlethread {}
-    multithread  {fast static_lru static_master static_mem static_prng }
-    serialized  {fast recursive static_lru static_master static_mem static_prng}
+    multithread  {fast static_lru static_master static_mem static_open static_prng }
+    serialized  {fast recursive static_lru static_master static_mem static_open static_prng}
   } {
 
     do_test mutex1.2.$mode.1 {