6.3.3 Configuring OCFS2 Tracing

The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

6.3.3 Configuring OCFS2 Tracing

The following table shows some of the commands that are useful for tracing problems in OCFS2.

Command	Description
debugfs.ocfs2 -l	List all trace bits and their statuses.
debugfs.ocfs2 -l SUPER allow	Enable tracing for the superblock.
debugfs.ocfs2 -l SUPER off	Disable tracing for the superblock.
debugfs.ocfs2 -l SUPER deny	Disallow tracing for the superblock, even if implicitly enabled by another tracing mode setting.
debugfs.ocfs2 -l HEARTBEAT \ ENTRY EXIT allow	Enable heartbeat tracing.
debugfs.ocfs2 -l HEARTBEAT off \ ENTRY EXIT deny	Disable heartbeat tracing. `ENTRY` and `EXIT` are set to deny as they exist in all trace paths.
debugfs.ocfs2 -l ENTRY EXIT \ NAMEI INODE allow	Enable tracing for the file system.
debugfs.ocfs2 -l ENTRY EXIT \ deny NAMEI INODE allow	Disable tracing for the file system.
debugfs.ocfs2 -l ENTRY EXIT \ DLM DLM_THREAD allow	Enable tracing for the DLM.
debugfs.ocfs2 -l ENTRY EXIT \ deny DLM DLM_THREAD allow	Disable tracing for the DLM.

One method for obtaining a trace its to enable the trace, sleep for a short while, and then disable the trace. As shown in the following example, to avoid seeing unnecessary output, you should reset the trace bits to their default settings after you have finished.

# debugfs.ocfs2 -l ENTRY EXIT NAMEI INODE allow && sleep 10 && \
  debugfs.ocfs2 -l ENTRY EXIT deny NAMEI INODE off

To limit the amount of information displayed, enable only the trace bits that you believe are relevant to understanding the problem.

If you believe a specific file system command, such as mv, is causing an error, the following example shows the commands that you can use to help you trace the error.

# debugfs.ocfs2 -l ENTRY EXIT NAMEI INODE allow
# mv source destination & CMD_PID=$(jobs -p %-)
# echo $CMD_PID
# debugfs.ocfs2 -l ENTRY EXIT deny NAMEI INODE off

As the trace is enabled for all mounted OCFS2 volumes, knowing the correct process ID can help you to interpret the trace.

For more information, see the debugfs.ocfs2(8) manual page.