Journaling UFS with gjournal.

[R. B. Riddick]

--- Pawel Jakub Dawidek <pjd at FreeBSD.org> wrote:
> On Mon, Jun 19, 2006 at 06:37:06AM -0700, R. B. Riddick wrote:
> +> --- Pawel Jakub Dawidek <pjd at FreeBSD.org> wrote:
> +> > 2. If we have file system, synchronize it.
> +> > 3. Mark file system as clean.
> +> > 4. Block all write requests to the file system.
> +> >
> +> Shouldn't we do 4. before 2.?
> 
> 4 is done via vfs_write_suspend() function, which synchronize file
> system once again.
>
OK. Does vfs_write_suspend mark the file system as clean again, too?
I mean: What if bewteen step 3 and 4 someone makes the file system dirty?

> As I said gjournal is below file system layer. It receives I/O requests
> only and cannot say which one is related to growing file, which has
> metadata inside, etc.
> 
Yeah, below -- as u said in the email, I responded to...
I thought, the file system code supports gjournal somehow in that point, too...
And I was too lazy to look into the patch u provided...

Might it be possible to get some more optional assistance by the file system?
Maybe we could provide a /dev/ad0.gjournal and a /dev/ad0.fs-data, which would
break the GEOM concept a little bit...? *sigh*
Maybe the file system code could use negative block numbers or high block
numbers (somehow like a hint: U can write it right to the file system without
any worries)?
Of course those quick-write-through blocks should not be subject to a remove
operation in the currently active journal area (I mean just in case, the system
crashes while that journal is still active)...

*sigh* I hope, I do not disturb the list too much...

But I still like the BIO_FLUSH...

-Arne
---
Arne slow sometimes... :-)

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