[Ocfs2-tools-devel] Re: [Ocfs2-devel] [patch 1/1] offline de-fragmentation tool

[wengang wang]

tao.ma wrote:
> Many typos. So please revise them.
>
revised some :)
> Some comments:
> a) In "implementation detail:"
>     5. does step 4 and step 5, until there is only on group in the 
> 'left' groups. Strange? do step 5 in step 5?
changed the statement in another way.
5.  runs from step 4, until there is only on group in the 'left' groups.

> b) As Sunil has said in the previous e-mail, writing order is a *MUST* 
> in ocfs2-tools. but it seems that your design doc doesn't resolve this 
> problem. So do please improve it until it is OK. You have already 
> mentioned in the doc: doesn't garantee safety when power down during 
> the procedure of defragmentation(needs to be improved). ;)
yea, writing order is MUST, but since won't continue working on this 
off-line tool any longer, I just added a comment:
--
as seen, updating inodes/extents and committing groups to disk are done 
very late. this aims getting better performance of this tool. But in 
case of error, this may be done partially or not done at all. -- to be 
improved.
--
to point out this problem.  and also, I don't know how to write order 
off-line as user app.
though as you said, we should update the extent and groups just after 
copying data clusters, I don't think it's enough.
disk writing can only guarantee writing a 512 bits(1 sector), so it also 
dangerous to have a group committed to disk partially.

> Thank again for your hard work in this issue.
:) glad to do that.

wengang.