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Changes to avoid deadlock in SQLITE_ENABLE_SETLK_TIMEOUT builds.

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FossilOrigin-Name: 553423c23142cf0ec219192315d57ce8a0e10c3d8678d28bc110a1a9a7c17cee
This commit is contained in:
dan
2020-05-04 19:42:35 +00:00
parent 995e1af9fa
commit 8714de97c0
10 changed files with 162 additions and 175 deletions
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48
src/main.c
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@@ -1551,8 +1551,7 @@ const char *sqlite3ErrStr(int rc){
*/
static int sqliteDefaultBusyCallback(
void *ptr, /* Database connection */
int count, /* Number of times table has been busy */
sqlite3_file *pFile /* The file on which the lock occurred */
int count /* Number of times table has been busy */
){
#if SQLITE_OS_WIN || HAVE_USLEEP
/* This case is for systems that have support for sleeping for fractions of
@@ -1566,31 +1565,6 @@ static int sqliteDefaultBusyCallback(
int tmout = db->busyTimeout;
int delay, prior;
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
if( count ){
/* If this is the second or later invocation of the busy-handler,
** but tmout==0, then code in wal.c must have disabled the blocking
** lock before the SQLITE_BUSY error was hit. In this case, no delay
** occurred while waiting for the lock, so fall through to the xSleep()
** code below to delay a while before retrying the lock.
**
** Alternatively, if tmout!=0, then SQLite has already waited
** sqlite3.busyTimeout ms for a lock. In this case, return 0 to
** indicate that the lock should not be retried and the SQLITE_BUSY
** error returned to the application. */
if( tmout ){
tmout = 0;
sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
return 0;
}
}else{
return 1;
}
}
#else
UNUSED_PARAMETER(pFile);
#endif
assert( count>=0 );
if( count < NDELAY ){
delay = delays[count];
@@ -1610,7 +1584,6 @@ static int sqliteDefaultBusyCallback(
** must be done in increments of whole seconds */
sqlite3 *db = (sqlite3 *)ptr;
int tmout = ((sqlite3 *)ptr)->busyTimeout;
UNUSED_PARAMETER(pFile);
if( (count+1)*1000 > tmout ){
return 0;
}
@@ -1631,16 +1604,7 @@ static int sqliteDefaultBusyCallback(
int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
int rc;
if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
if( p->bExtraFileArg ){
/* Add an extra parameter with the pFile pointer to the end of the
** callback argument list */
int (*xTra)(void*,int,sqlite3_file*);
xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
rc = xTra(p->pBusyArg, p->nBusy, pFile);
}else{
/* Legacy style busy handler callback */
rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
}
rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
if( rc==0 ){
p->nBusy = -1;
}else{
@@ -1665,7 +1629,6 @@ int sqlite3_busy_handler(
db->busyHandler.xBusyHandler = xBusy;
db->busyHandler.pBusyArg = pArg;
db->busyHandler.nBusy = 0;
db->busyHandler.bExtraFileArg = 0;
db->busyTimeout = 0;
sqlite3_mutex_leave(db->mutex);
return SQLITE_OK;
@@ -1716,7 +1679,6 @@ int sqlite3_busy_timeout(sqlite3 *db, int ms){
sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
(void*)db);
db->busyTimeout = ms;
db->busyHandler.bExtraFileArg = 1;
}else{
sqlite3_busy_handler(db, 0, 0);
}
@@ -3359,7 +3321,7 @@ static int openDatabase(
#endif
#ifdef SQLITE_ENABLE_BYTECODE_VTAB
if( !db->mallocFailed && rc==SQLITE_OK){
if( !db->mallocFailed && rc==SQLITE_OK ){
rc = sqlite3VdbeBytecodeVtabInit(db);
}
#endif
@@ -4520,11 +4482,11 @@ int sqlite3_snapshot_open(
rc = SQLITE_OK;
}
if( rc==SQLITE_OK ){
rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
rc = sqlite3PagerSnapshotOpen(pPager, db, pSnapshot);
}
if( rc==SQLITE_OK ){
rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
sqlite3PagerSnapshotOpen(pPager, 0);
sqlite3PagerSnapshotOpen(pPager, 0, 0);
}
if( bUnlock ){
sqlite3PagerSnapshotUnlock(pPager);