Turn on debug logging

Enable the full cetrafs trace at runtime with dynamic debug, narrow it to a file or function, and turn it off again. No rebuild or remount needed.

By default, cetrafs logs only errors, warnings and lifecycle events (mount, unmount, Zone Group claims, lease revocations, journal replays, controls changes). A full mount and unmount produces about seven lines. Everything per-operation is compiled in at pr_debug level and switched off.

Turn the trace on

This uses the kernel’s dynamic debug facility (CONFIG_DYNAMIC_DEBUG, enabled on Debian and Proxmox kernels):

# everything the module can say
echo 'module cetrafs +p' | sudo tee /sys/kernel/debug/dynamic_debug/control

Narrow it down:

echo 'file dir.c +p'          | sudo tee /sys/kernel/debug/dynamic_debug/control
echo 'func cetrafs_lookup +p' | sudo tee /sys/kernel/debug/dynamic_debug/control

Add the function name and line number to each message:

echo 'module cetrafs +pfl' | sudo tee /sys/kernel/debug/dynamic_debug/control

Turn it off

echo 'module cetrafs -p' | sudo tee /sys/kernel/debug/dynamic_debug/control

See what’s available

sudo grep cetrafs /sys/kernel/debug/dynamic_debug/control

Settings are cleared when the module unloads and aren’t kept across a reboot. To enable the trace from module load, pass dyndbg:

sudo modprobe cetrafs dyndbg='+p'

On a kernel built without CONFIG_DYNAMIC_DEBUG, the debug lines are compiled out, and getting them back means rebuilding the module with -DDEBUG.

Last updated 21 October 2026