Messages in this thread | | | Date | Fri, 14 Mar 2014 06:23:23 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH 1/1] block: rework flush sequencing for blk-mq |
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On Fri, Mar 14, 2014 at 09:00:21AM -0400, Mike Snitzer wrote: > > Getting a little upset, eh? I didn't say it's broken, I said it gets > > very little testing. The regression from me was found like so many > > before only after it was backported o some enterprise kernel. > > Even _really_ basic dm-multipath testing would've uncovered this bug.
But major testing using dm, md and various low-level drivers didn't. Do you really expect everyone to remember to specificly test dm-multipath for a core block change? Without a nicely documented way to do it?
That being said I should have remembered that it's special, but even I didn't and I'm sorry about that.
> > I think the problem here is two-fold: > > a) the hardware you use with dm-multipath isn't widely available. > > b) it uses a very special code path in the block layer no one else uses > > > > a) might be fixable by having some RDAC or similar emulation in qemu if > > someone wants to spend the effort. > > The regression from the commit in question was easily reproduced/tested > using scsi_debug. Just start the multipathd service and any scsi_debug > device in the system will get multipath'd.
Really? That sounds a like a bug in the INQUIRY information returned by scsi_debug. Either way please write up these things in Documentation so you can point people at it easily.
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