On Wed, Feb 26, 2014 at 12:29:22PM -0600, Eric Sandeen wrote: > On 2/25/14, 8:11 PM, Christoph Hellwig wrote: > > On Mon, Feb 24, 2014 at 11:27:35PM -0600, Eric Sandeen wrote: > >> xfs_set_maxicount() overflowed fairly easily for large filesystems > >> and large maxicount; we started out by multiplying dblocks by > >> the percentage, *then* dividing by 100, and never checked for > >> an overflow. The calculations were also, IMHO, a little hard > >> to follow. > > > > Would be useful to get this test case into xfstests.. > > Ok so I was going on Dave's assertion about that. ;) > > To overflow, we'd need dblocks * 100 to be > 2^64-1: > > so dblocks would need to be > (2^64-1)/100 > > for 4k blocks that's 655 exabytes. Maybe not so possible after all ;) Until the block count is corrupted by fsfuzzer? ;) > Dave, maybe just removing the open-code is enough here. Sure, but I still like the conversion to use mult_frac.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
