ループバックデバイスを使って普通のファイルをXFSファイルシステムとしてマウントしてみる ref: http://qiita.com/kentarosasaki/items/b3808694a4aec1a83388

file0.swift

$ sudo apt-get install -y xfsprogs

file1.txt

$ sudo mkdir -p /srv/node/images
$ sudo touch /srv/node/images/file.img

file2.txt

$ sudo truncate -s 50G /srv/node/images/file.img

file3.txt

$ sudo /sbin/mkfs.xfs -f -i size=1024 /srv/node/images/file.img
meta-data=/srv/node/images/file.img isize=1024   agcount=4, agsize=3276800 blks
         =                       sectsz=512   attr=2, projid32bit=0
data     =                       bsize=4096   blocks=13107200, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal log           bsize=4096   blocks=6400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

file4.txt

$ file /srv/node/images/file.img
/srv/node/images/file.img: SGI XFS filesystem data (blksz 4096, inosz 1024, v2 dirs)

file5.txt

$ sudo mkdir -p /mnt/loop0

file6.txt

$ sudo mount -t xfs -o loop,noatime,nodiratime,nobarrier,logbufs=8 /srv/node/images/file.img /mnt/loop0

file7.txt

$ df -h | grep loop0
/dev/loop0       50G   33M   50G   1% /mnt/loop0