Add missing mutexes to unixShmClose().

FossilOrigin-Name: a4741cb54dd5e753d48fd05ac9dbe27ee4aa1ec0

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\scouple\sof\sassert()\sstatements\sin\sos_unix.c\sand\swal.c.\sCombine\ssqlite3WalIsDirty()\swith\ssqlite3WalUndo().
-D 2010-04-30T09:52:18
+C Add\smissing\smutexes\sto\sunixShmClose().
+D 2010-04-30T10:06:10
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in d83a0ffef3dcbfb08b410a6c6dd6c009ec9167fb
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -150,7 +150,7 @@ F src/os.c 8bc63cf91e9802e2b807198e54e50227fa889306
 F src/os.h 534b082c3cb349ad05fa6fa0b06087e022af282c
 F src/os_common.h 0d6ee583b6ee3185eb9d951f890c6dd03021a08d
 F src/os_os2.c 8ad77a418630d7dee91d1bb04f79c2096301d3a0
-F src/os_unix.c 685b0347383b5d12dee9961b3cc0337ff075617b
+F src/os_unix.c f5e41bd2f563f85c10a9c9e62bbac8e3b783efc3
 F src/os_win.c a8fc01d8483be472e495793c01064fd87e56a5c1
 F src/pager.c 434f9751fc2dfc11ade004282deda5f8560bcba2
 F src/pager.h 934b598583a9d936bb13c37d62a2fe68ac48781c
@@ -808,7 +808,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 72b95fde15dae56390dc8d4168fb2757447e289e
-R 8864259ed44807eea46d7c4986422a72
+P a8f958be804ee05c4137b3cd110db344713af5f2
+R 5f2e996a1ab6f83c7e08f128286e26ff
 U dan
-Z 967d048f88e642230f471eb242428feb
+Z 8a044884de878c7767a8936662f5ee57

manifest.uuid

@@ -1 +1 @@
-a8f958be804ee05c4137b3cd110db344713af5f2
+a4741cb54dd5e753d48fd05ac9dbe27ee4aa1ec0

src/os_unix.c

@@ -5046,7 +5046,6 @@ static int unixShmClose(sqlite3_shm *pSharedMem){
   unixShm *p;            /* The connection to be closed */
   unixShmFile *pFile;    /* The underlying shared-memory file */
   unixShm **pp;          /* For looping over sibling connections */
-  int nRef;              /* Number of connections to pFile */
 
   if( pSharedMem==0 ) return SQLITE_OK;
   p = (struct unixShm*)pSharedMem;
@@ -5056,13 +5055,10 @@ static int unixShmClose(sqlite3_shm *pSharedMem){
   assert( p->exclMask==0 );
   assert( p->sharedMask==0 );
 
-
   /* Remove connection p from the set of connections associated with pFile */
   sqlite3_mutex_enter(pFile->mutex);
   for(pp=&pFile->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
   *pp = p->pNext;
-  pFile->nRef--;
-  nRef = pFile->nRef;
 
   /* Free the connection p */
   sqlite3_free(p);
@@ -5070,9 +5066,14 @@ static int unixShmClose(sqlite3_shm *pSharedMem){
 
   /* If pFile->nRef has reached 0, then close the underlying
   ** shared-memory file, too */
-  if( nRef==0 ){
+  unixEnterMutex();
+  assert( pFile->nRef>0 );
+  pFile->nRef--;
+  if( pFile->nRef==0 ){
     unixShmPurge();
   }
+  unixLeaveMutex();
+
   return SQLITE_OK;
 }