On Fri, Aug 02, 2019 at 11:19:39AM +0200, Carlos Maiolino wrote: > Hi Darrick. > > > > + return error; > > > + > > > + block = ur_block; > > > + error = bmap(inode, &block); > > > + > > > + if (error) > > > + ur_block = 0; > > > + else > > > + ur_block = block; > > > > What happens if ur_block > INT_MAX? Shouldn't we return zero (i.e. > > error) instead of truncating the value? Maybe the code does this > > somewhere else? Here seemed like the obvious place for an overflow > > check as we go from sector_t to int. > > > > The behavior should still be the same. It will get truncated, unfortunately. I > don't think we can actually change this behavior and return zero instead of > truncating it. But that's even worse, because the programs that rely on FIBMAP will now receive *incorrect* results that may point at a different file and definitely do not point at the correct file block. Note also that the iomap (and therefore xfs) implementation WARNs on integer overflow and returns 0 (error) to prevent an incorrect access. --D > > --D > > > > > + > > > + error = put_user(ur_block, p); > > > + > > > + return error; > > > } > > > > > > /** > > > -- > > > 2.20.1 > > > > > -- > Carlos
