EC
EBUSY
Linux / POSIXERRORNotableDevicesHIGH confidence

Device or Resource Busy

What this means

The device or resource is currently in use by another process or mount point and cannot be accessed as requested. This is commonly encountered when trying to unmount a filesystem that has open files, or reformatting a mounted partition.

Why it happens
  1. 1Trying to unmount a filesystem while processes have files open on it.
  2. 2Attempting to remove or change a swap partition while it is active.
  3. 3Creating a loop device that is already in use.
  4. 4Deleting a module that a loaded driver depends on.
How to reproduce

Unmounting a filesystem while a shell is working inside it.

trigger — this will error
trigger — this will error
$ umount /mnt/data
umount: /mnt/data: target is busy

expected output

umount: /mnt/data: target is busy

Fix

Find and stop processes using the mount point

WHEN When trying to unmount a filesystem

Find and stop processes using the mount point
# List processes using the mount point
sudo fuser -vm /mnt/data

# Or use lsof
lsof +D /mnt/data

# Kill all processes using it (use with care)
sudo fuser -km /mnt/data
sudo umount /mnt/data

Why this works

fuser identifies which processes have files open on the mount point. Stopping them releases the hold on the filesystem.

Sources
Official documentation ↗

Linux Programmer Manual errno(3)

fuser(1) ↗

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