DiskLoc MmapV1ExtentManager::_createExtent( OperationContext* txn,
int size,
bool enforceQuota ) {
size = quantizeExtentSize( size );
if ( size > maxSize() )
size = maxSize();
verify( size < DataFile::maxSize() );
for ( int i = numFiles() - 1; i >= 0; i-- ) {
DataFile* f = _getOpenFile(i);
invariant(f);
if ( f->getHeader()->unusedLength >= size ) {
return _createExtentInFile( txn, i, f, size, enforceQuota );
}
}
_checkQuota( enforceQuota, numFiles() );
// no space in an existing file
// allocate files until we either get one big enough or hit maxSize
for ( int i = 0; i < 8; i++ ) {
DataFile* f = _addAFile( txn, size, false );
if ( f->getHeader()->unusedLength >= size ) {
return _createExtentInFile( txn, numFiles() - 1, f, size, enforceQuota );
}
}
// callers don't check for null return code, so assert
msgasserted(14810, "couldn't allocate space for a new extent" );
}
DiskLoc MmapV1ExtentManager::_createExtentInFile(
OperationContext* txn, int fileNo, DataFile* f, int size, bool enforceQuota) {
_checkQuota(enforceQuota, fileNo - 1);
massert(10358, "bad new extent size", size >= minSize() && size <= maxSize());
DiskLoc loc = f->allocExtentArea(txn, size);
loc.assertOk();
Extent* e = getExtent(loc, false);
verify(e);
*txn->recoveryUnit()->writing(&e->magic) = Extent::extentSignature;
*txn->recoveryUnit()->writing(&e->myLoc) = loc;
*txn->recoveryUnit()->writing(&e->length) = size;
return loc;
}