On 11/11/19 8:55 AM, Kevin Willford wrote: >> >> The istate->cache[] is a dynamic array whose size is managed via the usual >> ALLOC_GROW() using istate->cache_nr and istate->cache_alloc, whether the >> split-index feature is in use. When your patch makes a difference, then, >> doesn't the access to istate->cache[] pick up a random garbage and then flip >> the bit? >> >> Puzzled... In any case, "check is worse than over-eager, it simply is wrong" I >> wrote in the message I am responding to is totally incorrect, it seems. It >> smells like lifting the check would just hide the underlying problem under the >> rug? > > I agree. The only 2 places that excluding the split-index make sense are in > read_fsmonitor_extension and write_fsmonitor_extension because the > index_state that is being passing into those methods could be the delta index > in which case the number of entries for the fsmonitor bitmap would almost > always be more and cause the BUG to be hit which it should not be. > > The reason it is not needed and should not be in the other 2 places is they > are ran from tweak_fsmonitor which is ran at post_read_index_from which > is after the base and delta indexes have been loaded into the indes_state and > the index_state will have all the entries and if the fsmonitor bitmap is bigger > than the number of entries then the BUG should be hit. > I agree. While working on the 3444ec2e patch I missed that read_fsmonitor_extension and write_fsmonitor_extension could be called with the delta index rather than the full index. I think it makes sense to leave the check in the other two places. Thanks, William
