Is removing a HDD after umount, without remove, considered safe?

Hi

I want to integrate a dm-crypted USB-HDD with autofs.

The first part of setting up dm-crypt can be put into udev, so that the dm-crypt-device is setup immediatly after plugging in the HDD, which in turn can then be used with autofs.

So my question is: Is it safe to unplug the HDD after the filesystem is umounted, but with the dm-crypt-device still in existance? (IOW: Are all dirty blocks immediately written to the HDD (at least at umount-time), or can there be something still buffered in the dm-crypt device?)

Bis denn

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