Re: The argument for fs assistance in handling archives

Hans Reiser
2004-09-03T06:01:29Z

David Masover wrote:

> Spam wrote:
> [...]
> |> I thought reiser4 had its journaling and atomic commits. Am I
> |> mistaken? I run reiser4 as primary fs on my test systems and it seem
> |> to work as expected.
>
> consider this:
>
> save_file () {
> write() /* what if the write flushes halfway through
> * then crashes?

reiser4 does protect from this. reiserfs v3 does not.

> */
>
> blah() /* what if "blah" crashes? */
> write()
> }
>
> Some apps need consistency across multiple files, but we don't even have
> it on a single file. You need a new interface to do that. As you can
> see, reiser4 has absolutely no way of knowing, anywhere in the above
> code, when you're done writing -- and when the file is consistent.
>
> AFAIK, all that has to be done now for this to work is for them to
> finish the userland interface to the journalling and atomic commits that
> already exist for kernel space. But so far, all that is truly atomic is
> metadata operations -- chmod, mv, mkdir, touch, and rm/rmdir are all
> atomic, so long as you only use them on a single file/dir. But this has
> been true in reiserfs3, xfs, ext3, and others.