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Yang
Asked: 2014-02-25 12:59:36 +0800 CST

How to unmount when umount hangs due to disconnected disk?

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I have an external disk connected via USB that was accidentally disconnected uncleanly. Now lsing the directory in which it was mounted gives Input/output error. umounting the directory simply hangs. dmesg just contains:

[3360010.363235] usb 2-1.1: USB disconnect, device number 3

How do I resolve this (short of rebooting), i.e. how do I clean up kernel state upon unclean disconnect of an external storage device?

usb

3 Answers

  1. Lazy unmount usually does the trick.

    sudo umount -l /path/where/its/mounted

    For more info try man umount.

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  2. You should also be able to do

    sudo umount -f /path/to/mount

    From man umount:

       -f     Force unmount (in case of an unreachable NFS system).  (Requires
          kernel 2.1.116 or later.)
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  3. Just posting this here in hopes that it might help someone reading this in the future. I had a share mapped to /tmp/delete-me and anytime I'd type out the share path, /tmp/delete-m_ it would stop before I could complete typing the full name. This is why the suggestions on force unmounting won't work.

    My workaround was to first set a variable using the read built-in command, and then unmount using the variable name.

    # If zsh
read "sharePath?Enter the path to the share to be removed: "

# If bash
read -p "Enter the path to the share to be removed: " sharePath

sudo umount $sharePath
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