pkg/disk: add XFS agcount option in disk.yaml

[jbtrystram]

The mkfs.xfs stage already support setting the XFS agcount so this is wiring it up to a disk.yaml option.

I went with a similar approach as #1825

Assisted-by: Opencode.ai <Opus-4.6>

[achilleas-k]

Thanks for the PR. Small change request for the configuration structure for consistency.

[achilleas-k]

I don't like the inconsistency here of having an fstype-specific option block only for this option. The geometry and verity options are for fat and ext4 respectively and don't define a sub-struct for the filesystems. Let's put the AGCount under MkfsOptions directly for consistency.
We can rethink the structure and whether we want to make sub-structs for each filesystem another time.

[jbtrystram]

Done ! thanks for the review

[jbtrystram]

Tested this with a fresh build of FCOS to confirm everything works :

core@cosa-devsh:~$ cat /usr/lib/image-builder/bootc/disk.yaml 
# We don't want osbuild to inject mount units for the
# disks as we will change the disks uuids anyway
mount_configuration: none
partition_table:
  type: "gpt"
  uuid: "00000000-0000-4000-a000-000000000001"
  # Reserve the last 2048 512-byte blocks for CoreOS which moves the
  # secondary GPT header to the end of the disk on first boot.
  # See https://github.com/coreos/fedora-coreos-config/blob/7fbf510367d495529d2a915707b547d4c663f609/overlay.d/05core/usr/lib/dracut/modules.d/35coreos-ignition/coreos-gpt-setup.sh#L30
  extra_padding: 1031168
  partitions:
    # BIOS Boot partition — required for legacy BIOS boot on x86_64
    - label: "BIOS-BOOT"
      size: "1 MiB"
      bootable: true
      type: 21686148-6449-6E6F-744E-656564454649

    # EFI System Partition
    - label: "EFI-SYSTEM"
      size: "127 MiB"
      type: C12A7328-F81F-11D2-BA4B-00A0C93EC93B
      payload_type: "filesystem"
      payload:
        type: "vfat"
        mountpoint: "/boot/efi"
        label: "EFI-SYSTEM"
        fstab_options: "umask=0077,shortname=winnt"
        fstab_freq: 0
        fstab_passno: 2

    # Extended Boot Loader partition
    - label: "boot"
      size: "384 MiB"
      type: BC13C2FF-59E6-4262-A352-B275FD6F7172
      payload_type: "filesystem"
      payload:
        type: "ext4"
        uuid: "96d15588-3596-4b3c-adca-a2ff7279ea63"
        mountpoint: "/boot"
        label: "boot"
        fstab_options: "defaults"
        fstab_freq: 0
        fstab_passno: 0

    # Root partition — DPS type for x86_64
    - label: "root"
      type: 4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709
      payload_type: "filesystem"
      payload:
        type: "xfs"
        uuid: "910678ff-f77e-4a7d-8d53-86f2ac47a823"
        mountpoint: "/"
        label: "root"
        fstab_options: "defaults"
        fstab_freq: 0
        fstab_passno: 0
        mkfs_options:
          xfs:
            agcount: 2
core@cosa-devsh:~$ sudo xfs_info /sysroot
meta-data=/dev/vda4              isize=512    agcount=2, agsize=1244928 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=1
         =                       reflink=1    bigtime=1 inobtcount=1 nrext64=1
         =                       exchange=1   metadir=0
data     =                       bsize=4096   blocks=2489856, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1, parent=1
log      =internal log           bsize=4096   blocks=16384, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
         =                       rgcount=0    rgsize=0 extents
         =                       zoned=0      start=0 reserved=0

[achilleas-k]

Nice work. Thank you!

[achilleas-k]

Adding to the merge queue again. The failure should be fixed by #2467 (which is already on the queue right now).