device-mapper: reload ioctl ... failed: No such file or directory

Hello,

I'm using cryptsetup 2.7.5 on Gentoo to try to open an old TrueCrypt volume that I haven't
looked at in at least a few years. Yes, I have the passphrase :=)  Below is a trace of what's
happening. Without --debug, all I see is the error message:

  device-mapper: reload ioctl on coreswp (254:0) failed: No such file or directory

Any help in figuring this out would be much appreciated.

Dave

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root# cryptsetup open --debug --type tcrypt /mnt/disk1/core.swp coreswp
# cryptsetup 2.7.5 processing "cryptsetup open --debug --type tcrypt /mnt/disk1/core.swp coreswp"
# Verifying parameters for command open.
# Running command open.
# Installing SIGINT/SIGTERM handler.
# Unblocking interruption on signal.
# Allocating context for crypt device /mnt/disk1/core.swp.
# Trying to open and read device /mnt/disk1/core.swp with direct-io.
# Direct-io is supported and works.
# Initialising device-mapper backend library.
# Interactive passphrase entry requested.
Enter passphrase for /mnt/disk1/core.swp: 
# Trying to load TCRYPT crypt type from device /mnt/disk1/core.swp.
# Crypto backend (OpenSSL 3.3.2 3 Sep 2024 [default][legacy][threads][argon2]) initialized in cryptsetup library version 2.7.5.
# Detected kernel Linux 5.15.167-gentoo x86_64.
# Reading TCRYPT header of size 512 bytes from device /mnt/disk1/core.swp.
# TCRYPT: trying KDF: pbkdf2-ripemd160-2000.
# TCRYPT:  trying cipher aes-xts-plain64
# TCRYPT: Signature magic detected.
# TCRYPT: Magic: TRUE, Header version: 5, req. 1792, sector 512, mk_offset 131072, hidden_size 0, volume size 107373920256
# TCRYPT: Header cipher aes-xts-plain64, key size 64
# Activating volume coreswp [keyslot -1] using key.
# dm version   [ opencount flush ]   [16384] (*1)
# dm versions   [ opencount flush ]   [16384] (*1)
# Detected dm-ioctl version 4.45.0.
# Detected dm-crypt version 1.23.0.
# Device-mapper backend running with UDEV support enabled.
# dm status coreswp  [ opencount noflush ]   [16384] (*1)
# Allocating a free loop device (block size: 512).
# Trying to open and read device /dev/loop0 with direct-io.
# Direct-io is supported and works.
# Attached loop device block size is 512 bytes.
# Calculated device size is 209714688 sectors (RW), offset 256.
# Trying to activate TCRYPT device coreswp using cipher aes-xts-plain64.
# DM-UUID is CRYPT-TCRYPT-coreswp
# Udev cookie 0xd4dfe53 (semid 65598) created
# Udev cookie 0xd4dfe53 (semid 65598) incremented to 1
# Udev cookie 0xd4dfe53 (semid 65598) incremented to 2
# Udev cookie 0xd4dfe53 (semid 65598) assigned to CREATE task(0) with flags DISABLE_LIBRARY_FALLBACK         (0x20)
# dm create coreswp CRYPT-TCRYPT-coreswp [ opencount flush ]   [16384] (*1)
# dm reload   (254:0) [ opencount flush securedata ]   [16384] (*1)
device-mapper: reload ioctl on coreswp (254:0) failed: No such file or directory
# Udev cookie 0xd4dfe53 (semid 65598) decremented to 1
# Udev cookie 0xd4dfe53 (semid 65598) incremented to 2
# Udev cookie 0xd4dfe53 (semid 65598) assigned to REMOVE task(2) with flags DISABLE_LIBRARY_FALLBACK       (0x20)
# dm remove coreswp  [ opencount flush securedata ]   [16384] (*1)
# Uevent not generated! Calling udev_complete internally to avoid process lock-up.
# Udev cookie 0xd4dfe53 (semid 65598) decremented to 1
# DM create task failed, dm_task errno: 0.
# dm versions   [ opencount flush ]   [16384] (*1)
# dm status coreswp  [ opencount noflush ]   [16384] (*1)
# Device status returned -19.
# Data device /mnt/disk1/core.swp is OK.
# No referenced device missing, some device in use.
# Udev cookie 0xd4dfe53 (semid 65598) decremented to 0
# Udev cookie 0xd4dfe53 (semid 65598) waiting for zero
# Udev cookie 0xd4dfe53 (semid 65598) destroyed
# Releasing crypt device /mnt/disk1/core.swp context.
# Releasing device-mapper backend.
# Closing read only fd for /mnt/disk1/core.swp.
# Closed loop /dev/loop0 (/mnt/disk1/core.swp).
Command failed with code -5 (device already exists or device is busy).

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