[dm-crypt] LUKS1 devmapper device mount issue

Michael Kjörling michael at kjorling.se
Sat Apr 9 14:36:40 CEST 2016

On 8 Apr 2016 13:46 -0700, from amitnr at gmail.com (Amith Kumar Ramachandra):
> But when I format the device as ext4 and mount it at /mnt, I don't see the
> device mounted. The mount command itself did not fail. It gives me success
> (verified both from the return status and kernel dmesg logs) but the LUKS1
> device is not getting mounted.
> However, when I create a crypt device using dmsetup, I am able to see and
> mount the volume1 device as expected.

You are answering just about every question I can think of _except_
the really important ones in your case; that is, the ones that pertain
to actually _mounting_ the file system:

 * Exactly how are you creating a file system on ("formatting") the
   device? Show us the command(s) and output, ideally in debug or
   verbose mode (for mke2fs, that's -v). Also, for completeness, show
   us how they relate to the luksCreate, luksOpen and dmsetup info.
   You may want to throw in a luksDump (on the raw device) too, for
   good measure.

 * How are you mounting the file system? Show us the command(s) and
   the output if any.

 * How do you conclude that the mount command succeeds but the file
   system isn't being mounted? Show us the command(s), the output if
   relevant, the relevant portion of the kernel logs and what you are
   doing to conclude that the file system _isn't_ being mounted.

If relevant, you may also want to show us the relevant portions of
your /etc/crypttab (or similar; the name might differ based on
distribution). It's possible that /proc/mounts (after you have tried
to mount the file system) could be of interest as well. Sharing those
should be safe because (at least on Debian, as far as crypttab goes)
they do not generally by themselves contain any sensitive information.

Michael Kjörling • https://michael.kjorling.semichael at kjorling.se
                 “People who think they know everything really annoy
                 those of us who know we don’t.” (Bjarne Stroustrup)

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