You may run into the issue where that SD cards (like SSDs) may actually use larger block-sizes than exposed at the interface. Hence interrupting a write may damage parts that were not requested to be written. SSDs have that mostly under control now, I think, probably by adding some more complex commit schemes. But SD cards have far less comuting power and may not do that. Regards, Arno On Wed, Jan 20, 2021 at 12:06:24 CET, Frederick Gotham wrote: > > I'm developing a product running embedded Linux. > > We have an SDcard with one partition on it, and this partition is an > encrypted LUKS volume. > > While the SDcard is mounted, the user can spontaneously eject the > SDcard. I have successfully altered the UDEV script to handle this > eventuality, as follows: > > umount /mnt/sdcard > cryptsetup luksClose cryptocard > > Then when the user re-inserts the SDcard after a spontaneous ejection, > I try to re-mount it again. So the entire process from start to finish > goes as follows: > > echo -n password | cryptsetup luksOpen /dev/sdb1 cryptocard - > mount /dev/mapper/cryptocard /mnt/sdcard > [ User spontaneously ejects SDcard ] > umount /mnt/sdcard > cryptsetup luksClose cryptocard > [ ... ... ... 1 minute goes by ... ... ... ] > [ User re-inserts SD card ] > echo -n password | cryptsetup luksOpen /dev/sdb1 cryptocard - > mount /dev/mapper/cryptocard /mnt/sdcard > > This appears to work just fine, however when I try to do more complex > write operations, it starts to freak out a little (files that were > previously visible are no longer visible). When I reboot the machine, > everything's working fine again. > > So it seems that the system is not adequately recovering from the > spontaneous ejection of the SDcard. Do I need to somehow "flush out" > the LUKS system in order to successfully re-mount the volume? Is it > possible to 'restart' the LUKS subsystem to get this to work properly > again? I only ever have one LUKS volume open at a time so I don't have > to worry about closing other volumes before 'flushing out'. > > Frederick > _______________________________________________ > dm-crypt mailing list > dm-crypt@xxxxxxxx > https://www.saout.de/mailman/listinfo/dm-crypt -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@xxxxxxxxxxx GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx https://www.saout.de/mailman/listinfo/dm-crypt
