XFS on Software RAID

XFSをIDE Software RAID1上に構築しようとしたら、

# mkfs.xfs -f /dev/md/root
meta-data=/dev/md/root           isize=256    agcount=16, agsize=187633 blks
         =                       sectsz=512
data     =                       bsize=4096   blocks=3002128, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal log           bsize=4096   blocks=2560, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0
mkfs.xfs: size check failed
mkfs.xfs: filesystem failed to initialize

と失敗してしまいます。更にこのパーティションをマウントしようとすると、

# mount /dev/md/root /mnt
mount: Unknown error 990

となり、/var/log/mesagesにも

kernel: XFS: file system busy
kernel: fffffc004fcb7b78 000000000000012d fffffc00006a5eff fffffc00004d3eac
kernel:        fffffc00004d3774 0000000000000000 fffffc0042e9b700 0000000000000200
kernel:        fffffc00004d3eac fffffc0044e6f040 fffffc0042e9b700 0000000000000200
kernel:        fffffc00004dcf7c fffffc0044e6f000 0000000000000000 fffffc0044e6f800
kernel:        fffffc001276cbc0 fffffc005ffd2340 fffffc00004f414c fffffc005beaf400
kernel:        0000000000000000 fffffc001276cbc0 fffffc0044e6f800 fffffc005ffd2370
kernel: Trace:
kernel: [<fffffc00004d3eac>] xfs_readsb+0x13c/0x290
kernel: [<fffffc00004d3774>] xfs_mount_validate_sb+0x274/0x3e0
kernel: [<fffffc00004d3eac>] xfs_readsb+0x13c/0x290
kernel: [<fffffc00004dcf7c>] xfs_mount+0x1fc/0x500
kernel: [<fffffc00004f414c>] vfs_mount+0x3c/0x60
kernel: [<fffffc00004f3af0>] linvfs_fill_super+0x0/0x330
kernel: [<fffffc00004f3bdc>] linvfs_fill_super+0xec/0x330
kernel: [<fffffc000037a2e4>] get_sb_bdev+0x1d4/0x280
kernel: [<fffffc0000378d08>] alloc_super+0x28/0x190
kernel: [<fffffc00003794cc>] sget+0x16c/0x1b0
kernel: [<fffffc000037aa30>] sb_set_blocksize+0x30/0x80
kernel: [<fffffc000037a2c4>] get_sb_bdev+0x1b4/0x280
kernel: [<fffffc00004f3e3c>] linvfs_get_sb+0x1c/30
kernel: [<fffffc000037a6d8>] do_kern_mount+0x88/0x1a0
kernel: [<fffffc0000394f88>] do_new_mount+0xd8/0x120
kernel: [<fffffc00003958a8>] do_mount+0x1a8/0x1e0
kernel: [<fffffc0000395da0>] sys_mount+0xb0/0x140
kernel: [<fffffc0000395674>] copy_mount_options+0x84/0x110
kernel: [<fffffc0000395d80>] sys_mount+0x90/0x140
kernel: [<fffffc0000310a54>] entSys+0xa4/0xc0
kernel:
kernel: XFS: SB validate failed

などど、すごそうなメッセージが出力されています。さてどうしたものか…