Mounting exFat on Linux

Question

I was given a USB hard drive formatted in exFAT to mount on a system running Red Hat Enterprise Linux 6. I've installed the exfat-utils and fuse-exfat RPM's, but when I try to mount the exFAT partition, I get an error message about the device or resource being busy:

$ sudo mount.exfat /dev/sdd2 /media/usbdisk
FUSE exfat 1.0.1
fuse: mount failed: Device or resource busy

When I run fdisk -l, this is what I get:

$ sudo fdisk -l /dev/sdd

WARNING: GPT (GUID Partition Table) detected on '/dev/sdd'! The util fdisk doesn't support GPT. Use GNU Parted.

Note: sector size is 4096 (not 512)

Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes
255 heads, 63 sectors/track, 60800 cylinders
Units = cylinders of 16065 * 4096 = 65802240 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

    Device Boot      Start         End      Blocks   Id  System
    /dev/sdd1               1           5      307220   ee  GPT
    /dev/sdd2               5       60801  3906709504    7  HPFS/NTFS

How do I mount the /dev/sdd2 partition? I need to be able to write files to it.

Thanks!

Update: I tried running mkfs.exfat /dev/sdd2 and fsck.exfat /dev/sdd2, since the filesystem is empty. Both commands say that everything is fine, but mounting still doesn't work. Previously, I had plugged this drive into a Windows PC and was able to mount the partition.

Solution

OK, I've found a solution. When I ran lsof /dev/sdd I found that multipath was accessing /dev/sdd.

$ sudo lsof /dev/sdd
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME
multipath 3520 root   10r   BLK   8,48      0t0 17681614 /dev/sdd

This server is also connected to other storage devices that are being handled by multipath.

I ran multipath -ll and multipath -f to clear /dev/sdd from multipath, and then I was able to mount /dev/sdd2.

$ sudo multipath -ll
mpathd (35000000000000001) dm-8 LaCie,P9233
size=3.6T features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
  `- 15:0:0:0 sdd 8:48 active ready running

$ sudo multipath -f mpathd
$ sudo mount.exfat /dev/sdd2 /media/usbdisk
FUSE exfat 1.0.1
$ ls /media/usbdisk

Update 12/8/2014: So, I now have to mount a second USB drive on the same machine, also with an exFAT partition. This time, fdisk showed the partitions, but the partitions were not appearing in /dev and could not be opened when I tried to run mount.exfat. The solution was to run partprobe, which made the partitions appear in /dev, and then run mount.exfat.