Messages in this thread | | | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: ide errors in 7-rc1-mm1 and later | Date | Thu, 10 Jun 2004 02:45:33 +0200 |
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On Thursday 10 of June 2004 02:38, Andrew Morton wrote: > 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?
Not OK. Chris, pre and post flushes are for the same device. Journal may be on different device than filesystem!
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