can't fsck due to "/dev/sdc1 is in use"

[kronos]

Previously never had this problem but just updated the system (via pacman) and dmesg tells me that it is time to fsck one of my attached usb hard drives (sdc1). I make sure the drive is not mounted and run fsck /dev/sdc1 and get the following:

fsck from util-linux 2.24.1
e2fsck 1.42.9 (28-Dec-2013)
/dev/sdc1 is in use.
e2fsck: Cannot continue, aborting.


I have tried restarting the system making sure the drive isn't auto mounted and always get that error. Can anyone provide any pointers. Thanks.

[Geoff]

I started having the same problem about a week ago. There's a kernel process accessing the partition, and this process doesn't go away as it used to after umount. Here's how you can find it:

$this->bbcode_second_pass_code('', 'lsof | grep ^jbd2/sd')

[kronos]

Yes, I have that process running. I have tried killing it without success. Not sure what it is for so it may be lucky that I can't kill it. Have you had any success in getting rid of it?

[kronos]

Just realised what I posted was stupid. For me the lsof output is:

lsof | grep ^jbd2/sd
jbd2/sdb1 116 root cwd DIR 8,1 4096 2 /
jbd2/sdb1 116 root rtd DIR 8,1 4096 2 /
jbd2/sdb1 116 root txt unknown /proc/116/exe


sdb1 is my mounted hard drive. sdc1 is the drive that when I unmount I still have the "in use" problem. lsof doesn't detect any processes using sdc1.