On 04/11/2012 03:32 PM, Paolo Bonzini wrote: > Il 11/04/2012 04:42, Liu Yuan ha scritto: >> 1) if we use bdrv_close(), we rely on the assumption that backend >> storage will do flushing while interpreting this operation. This >> assumption might not always hold, for e.g, current sheepdog doesn't do >> flushing for bdrv_close(). So bdrv_flush() will be the safest method to >> push the data back. >> 2) explicit flushing is more maintainable, we don't need to guess if it >> does flushing internally if we use other function that flush implicitly. > > I think it is reasonable semantics that closing gets all data to storage. >
Yes, but if the buggy block driver dose not assure us of this semantics, we'll risk to lose data. Thanks, Yuan
