On 05/20/2015 03:51 PM, Daniel Phillips wrote: > On 05/20/2015 12:53 PM, Rik van Riel wrote: >> How does tux3 prevent a user of find_get_page() from reading from >> or writing into the pre-COW page, instead of the current page? > > Careful control of the dirty bits (we have two of them, one each > for front and back). That is what pagefork_for_blockdirty is about.
Ah, and of course it does not matter if a reader is on the pre-cow page. It would be reading the earlier copy, which might no longer be the current copy, but it raced with the write so nobody should be surprised. That is a race even without page fork. Regards, Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
