A long-standing bug in Pass 1 of fsck_ffs in which it is reading in blocks of inodes to check their block pointers. It failed to round up the size of the read to a disk block size. When disks would accept 512-byte aligned reads, the bug rarely manifested itself. But many recent disks will no longer accept 512-byte aligned reads but require 4096-byte aligned reads, so the failure to properly round-up read sizes to multiples of 4096 bytes makes the error much more likely to occur. Reported by: Peter Holm and others Tested by: Peter Holm and Rozhuk Ivan MFC after: 3 days Sponsored by: Netflix