On Thu, Nov 25, 2010 at 10:54:57PM +1100, Nick Piggin wrote: > On Thu, Nov 25, 2010 at 06:49:09PM +1100, Nick Piggin wrote: > > Second is confusing sync and async inode metadata writeout > > Core code clears I_DIRTY_SYNC and I_DIRTY_DATASYNC before calling > > ->write_inode *regardless* of whether it is a for-integrity call or > > not. This means background writeback can clear it, and subsequent > > sync_inode_metadata or sync(2) call will skip the next ->write_inode > > completely. > > Hmm, this also means that write_inode_now(sync=1) is buggy. It > needs to in fact call ->fsync -- which is a file operation > unfortunately, Christoph didn't you have some patches to move it > into an inode operation? No, it doesn't really make much sense either. But what I've slowly started doing is to phase out write_inode_now. For the cases where we really only want to write the inode we should use sync_inode_metadata. That only leaves two others callsers: - iput_final for a filesystem during unmount. This should be caught by the need to call ->sync_fs rule you mentioned above, but needs a closer audit. - nfsd. Any filesystem that cares should just use the commit_metadata export operations, which is a subsystem of ->fsync as it only need to guarantee that metadata is on disk, but not actually any file data - so no cache flush mess as in a real fsync implementation. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
