Il 18/06/2012 19:35, Stefan Hajnoczi ha scritto: >> > + /* Use O_DSYNC for write-through caching, no flags for write-back >> > caching, >> > + * and O_DIRECT for no caching. */ >> > + if ((bdrv_flags & BDRV_O_NOCACHE)) >> > + s->open_flags |= O_DIRECT; >> > + if (!(bdrv_flags & BDRV_O_CACHE_WB)) >> > + s->open_flags |= O_DSYNC; > Paolo has changed this recently, you might need to use > bs->enable_write_cache instead.
At the protocol (i.e. low-level backend) level you don't need to do anything really, if you implement bdrv_flush_to_disk correctly. Looking at BDRV_O_CACHE_WB will do no harm, it's just dead code. Paolo
