Extent* MmapV1ExtentManager::getExtent( const DiskLoc& loc, bool doSanityCheck ) const {
loc.assertOk();
Extent* e = reinterpret_cast<Extent*>( _getOpenFile( loc.a() )->p() + loc.getOfs() );
if ( doSanityCheck )
e->assertOk();
return e;
}
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" );
}
Record* ExtentManager::recordFor( const DiskLoc& loc ) const {
loc.assertOk();
const DataFile* df = _getOpenFile( loc.a() );
int ofs = loc.getOfs();
if ( ofs < DataFileHeader::HeaderSize ) {
df->badOfs(ofs); // will uassert - external call to keep out of the normal code path
}
return reinterpret_cast<Record*>( df->p() + ofs );
}