Hi, I'm trying to shrink a filesystem using resize_ffs(8), but I keep getting an error:
resize_ffs: read failed: Invalid argument Here's the setup: I start out with a 1GB disk with two 512MB partitions: $ sudo disklabel vnd0 [...] # size offset fstype [fsize bsize cpg/sgs] a: 1048576 0 4.2BSD 0 0 0 # (Cyl. 0 - 511) b: 1048576 1048576 4.2BSD 0 0 0 # (Cyl. 512 - 1023) d: 2097152 0 unused 0 0 # (Cyl. 0 - 1023) $ sudo newfs -C 2 /dev/rvnd0a [...] $ sudo newfs -C 2 /dev/rvnd0b [...] I can easily grow partitiona 'a' to the size of the full disk: $ sudo disklabel -e vnd0 [ becomes now: ] # size offset fstype [fsize bsize cpg/sgs] a: 2097152 0 4.2BSD 0 0 0 # (Cyl. 0 - 1023) d: 2097152 0 unused 0 0 # (Cyl. 0 - 1023) $ sudo fsck_ffs -f /dev/rvnd0a >/dev/null $ sudo resize_ffs /dev/rvnd0a [...] $ sudo mount /dev/vnd0a /mnt $ df -h /mnt Filesystem Size Used Avail %Cap Mounted on /dev/vnd0a 963M 1.0K 915M 0% /mnt Now trying to shrink it again: $ sudo umount /mnt $ sudo disklabel -e vnd0 [ back to two '1048576' sized partitions ] $ sudo fsck_ffs -y -f /dev/rvnd0b [ all ok ] $ sudo resize_ffs -v /dev/rvnd0b No change requested: already 524288 blocks $ sudo fsck_ffs -y -f /dev/rvnd0a ** /dev/rvnd0a CANNOT READ: BLK 2010160 CONTINUE? yes THE FOLLOWING DISK SECTORS COULD NOT BE READ: 2010160, 2010161, 2010162, 2010163, /dev/rvnd0a: CANNOT FIGURE OUT SECTORS PER CYLINDER $ sudo resize_ffs -v /dev/rvnd0a resize_ffs: read failed: Invalid argument $ So the second partition worked out just fine, but vnd0a could not be shrunk. (It's not surprising that fsck couldn't read the noted sectors prior to running resize_ffs, since those were now beyond its new size.) So... how do I shrink a filesystem? -Jan
