Advice? External USB harddrive accidentally unplugged (no activity at time). Re-plugged, but `mountpoint`/`findmnt`/`lsblk` disagree if mounted?

[(This really isn’t an unbuntu-specific question, but yeah…)]

So I just accidentally bumped and and unplugged the cable on an external USB harddrive.

  • There was no activity at the time.

  • It’s btrfs (one big partition the whole drive, about 2TB… (I think it’s spinning rust, not an SSD — I dunno, it’s just something I had in my box of random old things I inherited from I dunno where))

I just plugged it back in, and…

  • mountpoint [[path]] #=> "[[path]] is a mountpoint"

  • lsblk doesn’t show it as having a mountpoint

  • findmnt #=>

TARGET      SOURCE                              FSTYPE  OPTIONS                                                                                     
/           /dev/sda3[/@/.snapshots/1/snapshot] btrfs   rw,relatime,ssd,discard=async,space_cache=v2,subvolid=266,subvol=/@/.snapshots/1/snapshot   
└─[[path]]  /dev/sdb1                           btrfs   ro,nosuid,nodev,relatime,space_cache,subvolid=5,subvol=/                                    
  • but
    sudo ls [[path]]
    ls: reading directory '[[path]]': Input/output error

What should I do/check?

Like, I am aware of fsck,
but I don’t know anything specific about how/why to use it, or what related/alternative tools I should use…?

Basically, what are my unknown-unknowns here?
How are you generally supposed to deal with this kind of situation?

Asked By: dwawlyn


To answer my own question:
I should’ve made it more explicit that I was pretty sure that I could just do
umount [mountpoint]
or at the worst reboot,
but I figured I should first check in case someone went like:

no! don’t reboot yet!
first you should [do X]
because [arcane cache/journaling details that are probably beyond you]!

However, no one I asked seemed to know of any potential hidden landmines like that,
so I just did:

  • umount [mountpoint]
  • unplugged and replugged drive
  • remounted

and it seemed to work fine.

Answered By: dwawlyn