On Thu, Oct 09, 2008 at 10:12:55AM -0400, Chris Mason wrote: > On Thu, 2008-10-09 at 15:55 +0200, Nick Piggin wrote: > > On Thu, Oct 09, 2008 at 09:35:58AM -0400, Chris Mason wrote: > > > On Thu, 2008-10-09 at 15:27 +0200, Nick Piggin wrote: > > > > > > I don't think do_sync_mapping_range is broken as is. It simply splits > > > the operations into different parts. The caller can request that we > > > wait for pending IO first. > > > > It is. Not because of it's whacky API, but because it uses WB_SYNC_NONE. > > > > > > > WB_SYNC_NONE none just means don't wait for IO in flight, and there are > > > valid uses for it that will slow down if you switch them all to > > > WB_SYNC_ALL. > > > > To write_cache_pages it means that, but further down the chain (eg. > > block_write_full_page) it also means not to wait on other stuff. > > > > It has broadly meant "don't worry about data integirty" for a long time > > AFAIKS. > > Sadly it has broadly meant different things to different people ;) > You're right, block_write_full_page is broken. Well, I really just think it is do_sync_mapping_range that is broken. Because __sync_single_inode treats WB_SYNC_NONE as a general "nowait", so does __writeback_single_inode. Weakest semantics define the API :) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
