I am using XFS on small HDD (/dev/sdb1, less than 1TB) and storing many small files (-32KB). df -h and -i show that it has available space.

# df -hv
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3             127G   19G  102G  16% /
tmpfs                  16G     0   16G   0% /lib/init/rw
udev                   16G  168K   16G   1% /dev
tmpfs                  16G     0   16G   0% /dev/shm
/dev/sda1              99M   20M   75M  21% /boot
/dev/sdb1             136G  123G   14G  91% /mnt/sdb1
# df -iv
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/sda3            8421376   36199 8385177    1% /
tmpfs                4126158       5 4126153    1% /lib/init/rw
udev                 4124934     671 4124263    1% /dev
tmpfs                4126158       1 4126157    1% /dev/shm
/dev/sda1              26112     222   25890    1% /boot
/dev/sdb1            24905120 11076608 13828512   45% /mnt/sdb1

However I got No space left on device error.

# touch /mnt/sdb1/test
touch: cannot touch `/mnt/sdb1/test': No space left on device

I think inode64 issue is not related to this case because drive is less than 1TB and df -i shows that there are free inodes. I unmounted and mounted with -o inode64 but got the same error.

xfs_repair does not report any problem. xfs_info shows drive information as follows.

# xfs_info /dev/sdb1
meta-data=/dev/sdb1              isize=1024   agcount=16, agsize=2227764 blks
         =                       sectsz=512   attr=2
data     =                       bsize=4096   blocks=35644210, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=17404, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

Any ideas? Thanks!