Backup namenode initiates the checkpointing process.
As a part of checkpointing based on the timestamp it tries to download the FSImage or use the existing one.
Then it tries to save the FSImage.
During this time it tries to close the editLog streams.
Parallely when a client tries to close a file just after the checkpointing process closes the editLog Stream then we get an exception saying
java.io.IOException: java.lang.IllegalStateException: !!! WARNING !!! File system changes are not persistent. No journal streams.
Here the saveNameSpace api closes all the editlog streams resulting in this issue.