Re: ide errors in 7-rc1-mm1 and later

Andrew Morton
2004-06-10T00:36:28Z

Chris Mason <mason@suse.com> wrote:
>
> On Wed, 2004-06-09 at 19:50, Andrew Morton wrote:
> > Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl> wrote:
> > >
> > > Does journal has checksum or some other protection against failure during
> > > writing journal to a disk? If not than it still can be screwed even with
> > > ordered writes if we are unfortunate enough. ;-)
> >
> > A transaction is written to disk as two synchronous operations: write all
> > the data, wait on it, write the single commit block, wait on that.
> >
> > If the commit block were to hit disk before the data then we have a window
> > in which poweroff+recovery would replay garbage into the filesystem.
> >
> > So I think we have a bug in the current ext3 barrier implementation - we
> > need a blk_issue_flush() before submitting the buffer_ordered commit block.
>
> The IDE barriers are both a pre and post flush. If the commit block is
> ordered, before the commit block hits the disk we know all the blocks
> previously submitted are also on disk.
>

Oh, OK. Will the same apply to (for example) scsi?