On Tue, 06 Aug 2013 20:14:35 +0200 Martin Wilck <mwilck@xxxxxxxx> wrote: > Hi Neil, > > these patches break the unit test 10ddf-geometry. I saw the regression > with both patches applied. The problem occurs when subarrays are > deleted. With these patches in place, sync_metadata() will not overwrite > deleted conf records on disk, but lseek() over them instead. When the > meta data is read back, this will cause errors. > > I would like to ask you to play safe here and revert these patches. It > might be possible to fix the --kill-subarray problem, but there are > other possible scenarios where the number of valid conf records on a > disk decreases - I don't think we have a reliable way to check whether > it is safe to skip over empty entries. We must also be prepared for > other DDF implementations to read our meta data, so we must refrain from > putting any writing anything that might be confusing. > > Regards > Martin Yes, you are right. That wasn't such a good idea, thanks. I've changed it to allocate a large buffer (which is done for 'read' - and we use the same buffer), fill that in and write. That is a lot faster than lots of individual writes, due to the fact that the fd is O_DIRECT. Thanks, NeilBrown
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