Your confusion is due to the difference between mkfs and mkfs.xfs. The latter wants you to pass it the -f, but to the former, this is an invalid option. The -f must follow the -t xfs so that mkfs does not interpret it and only passes it to mkfs.xfs.
** Changed in: util-linux (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to util-linux in Ubuntu. https://bugs.launchpad.net/bugs/1535137 Title: Explanation bug in mkfs xfs Filesystem mkfs from util-linux 2.26.2 Status in util-linux package in Ubuntu: Invalid Bug description: mkfs from util-linux 2.26.2 during an exercise with creating xfs partitions on a Ubuntu 15.10 64 Bit virtual machine, I guess I found a bug. Explanation: When creating an xfs filesystem on a partition with a existing gpt table, the mkfs command return an error message with the advice to force the command to run by using the -f option (lowercase f) However, it wont work and as you can see at my bash text, the command tells me that -f (lowercase f) is an invalid option. I read the manpages of mkfs to determine what should be the correct option. Even here, the -f (lowercase f) is mentioned. -f Force overwrite when an existing filesystem is detected on the device. By default, mkfs.xfs will not write to the device if it suspects that there is a filesystem or partition table on the device already. So I tried the uppercase F (-F) to FORCE the command to overwrite everything which worked ! So there are 2 possibilities: #1 I am to dump to use a -f properly #2 The texts (man pages and stderr)are wrong written and should be replaced with a uppercase F. root@ubuntu:/mnt# mkfs -t xfs /dev/sdb2 mkfs.xfs: /dev/sdb2 appears to contain a partition table (gpt). mkfs.xfs: Use the -f option to force overwrite. root@ubuntu:/mnt# mkfs -tf xfs /dev/sdb2 mkfs: failed to execute mkfs.f: No such file or directory root@ubuntu:/mnt# mkfs -t -f xfs /dev/sdb2 mkfs: failed to execute mkfs.-f: No such file or directory root@ubuntu:/mnt# mkfs -f -t xfs /dev/sdb2 mkfs.ext2: invalid option -- 'f' root@ubuntu:/mnt# mkfs -F -t xfs /dev/sdb2 mke2fs 1.42.12 (29-Aug-2014) Found a gpt partition table in /dev/sdb2 Your mke2fs.conf file does not define the xfs filesystem type. Creating filesystem with 512000 1k blocks and 128016 inodes Filesystem UUID: 216b73d3-d57e-49b4-a288-b1a0ac9a5ce6 Superblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409 Allocating group tables: done Writing inode tables: done Writing superblocks and filesystem accounting information: done Please give a feedback if my observation is correct or wrong. With best regards Stephan H. Wenderlich To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/1535137/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp