I used makefs to create a UFS filesystem. The filesystem is marked clean but fsck reports errors. # makefs -s 4g /var/tmp/root-image /usr/obj/stage15 Calculated size of `/var/tmp/root-image': 4294967296 bytes, 27793 inodes Extent size set to 32768 density reduced from 154535 to 8192 /var/tmp/root-image: 4096.0MB (8388608 sectors) block size 32768, fragment size 4096 using 7 cylinder groups of 626.00MB, 20032 blks, 80128 inodes. super-block backups (for fsck -b #) at: 64, 1282112, 2564160, 3846208, 5128256, 6410304, 7692352 Populating `/var/tmp/root-image' Image `/var/tmp/root-image' complete # mdconfig -f /var/tmp/root-image md2 # fsck -p /dev/md2 /dev/md2: FILE SYSTEM CLEAN; SKIPPING CHECKS /dev/md2: clean, 145201 free (25 frags, 18147 blocks, 0.0% fragmentation) # fsck /dev/md2 ** /dev/md2 ** Last Mounted on ** Phase 1 - Check Blocks and Sizes UFS1 cylinder group 0 failed: cgp->cg_old_niblk ("14592") != sblock.fs_ipg ("80128") UFS1 cylinder group 0 failed: cgp->cg_old_niblk ("14592") != sblock.fs_ipg ("80128") CYLINDER GROUP 0: INTEGRITY CHECK FAILED REBUILD CYLINDER GROUP? [yn] y INVALID INODE I=5632 OWNER=root MODE=120755 SIZE=19 MTIME=Mar 15 06:46 2024 CLEAR? [yn] Inode number 5632 is 5632 lrwxr-xr-x 1 root wheel 19 Mar 15 06:46 /mnt/usr/share/locale/pt_BR.UTF-8/LC_CTYPE -> ../C.UTF-8/LC_CTYPE
This is related to bug #273725, which was considered harmless. In my case fsck wants to clear an inode.
Using makefs -o version=2 creates a filesystem that fsck likes because the cg_old_niblk field does not exist in UFS2.