[dm-devel] [PATCH] dm-raid: add RAID discard support

[Martin K. Petersen]

>>>>> "Christoph" == Christoph Hellwig <hch at infradead.org> writes:

Christoph>  - start adding a whitelist for ATA

As far as I know the sanity bits have been discussed in T13 but haven't
been agreed upon yet.

The hard part about the whitelist is that bad things only happen in rare
circumstances. However, we may be able to take some hints from here:

http://www.lsi.com/downloads/Public/RAID%20Controllers/RAID%20Controllers%20Common%20Files/MegaRAID_SAS3_936x-938x_Compatibility_List.pdf

Christoph> Alternatively we could get rid of discard_zeroes_data and
Christoph> stop the pretence of any sane behavior from discard, and
Christoph> instead expose an unmap bit through the blkdev_issue_zeroout
Christoph> stack for those callers who want to do a discard, but rely on
Christoph> zeroes. The end effect will be the same, just a different
Christoph> presentation.

Yep.

-- 
Martin K. Petersen	Oracle Linux Engineering