[sheepdog] [PATCH v3 1/3] sheep: handle VID overflow correctly

Liu Yuan namei.unix at gmail.com
Fri Feb 27 09:18:51 CET 2015


On Fri, Feb 27, 2015 at 01:46:14PM +0900, Hitoshi Mitake wrote:
> Current sheep cannot handle a case like this:
> 1. iterate snapshot creation and let latest working VDI have VID 0xffffff
> 2. create one more snapshot
> 
> This problem comes from invalid usage of find_next_zero_bit() of sheep.
> Current sheep checks its VID bitmap with find_next_zero_bit(). But the
> function has a subtle point we must care about. If we check a bitmap
> and whose right most bit is 1, it returns a number of the bit though
> the bit is not 0. It means

Is it possible to fix find_next_zero_bit() to return what it should in this
subtle case?

Thanks
Yuan



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