Re: v3 experimental data=ordered and logging speedups for 2.6.1

[Oleg Drokin <green@linuxhacker.ru>]

Hello!

On Wed, Feb 11, 2004 at 09:00:34AM -0500, Chris Mason wrote:

> > Anyway there should be absolutely zero problems with bdb, I looked in their code
> > and they have sanity checks that do not allow write size to be bigger than
> > some values that they think are safe (16K I think).
> Well, it was easiest to trigger with older rpm versions, but you'll get
> hit by eventually.  Keep in mind the suse autobuild system runs rpm
> thousands (hundreds of thousands) of times per day.  It wasn't an easy
> bug to hit.

What are the symptoms?

> > > 06-reiserfs-jh-2
> > > Adds data=ordered support, along with a journal header attached to
> > > the buffer head.  This allows for more efficient data=ordered support
> > > than I had in 2.4.x.
> > I have some comments on this one, too.
> > Replicating __block_commit_write just to make sure you add buffer to ordered
> > list seems to be overkill. You can easily put buffers to some temp list at
> > buffer allocation time and then just add entire temp list to ordered
> > buffers list, I think. 
> If you use the generic __block_commit_write, you've got to update i_size
> first to make sure the generic code doesn't do it.  There are a few

No.
The auto i_size update happens only if you use generic_commit_write(),
but I used block_commit_write() which does not do this.

> other tricky parts when the data=journal code is added.  We've already
> made our own file_write call, it doesn't make sense to warp it just to
> avoid our own __block_commit_write ;-)

Well, code duplication is not very good thing.

> > Also this will make handling of mmap write in the middle
> > of write a little bit more correct, I think. BTW, I do not see where do you
> > specially handle mmap writes so that they are written in correct order wrt
> > inode updates.
> Those changes are still only in my local tree.  I wanted to get the
> basic functionality out there for testing.

Well, I need the quota part too, before I can put that on my university's file
server to get more testing ;)))

Bye,
    Oleg