Removing all the logs which is used under --debug_fs flag

[raj-prince]

Description

Removing the logs which was used under --debug_fs flag. Keeping the flag for the future, in case we want to log in gcsfuse code.

Why?

• Logging via --debug_fs was subset of logging via --debug_fuse. So, we can use --debug_fuse flag while logging.
• At FS level gcsfuse only converts from syscall (fuse) to GCS api call.

Link to the issue in case of a bug fix.

Testing details

1. Manual -

• debug_fs flag is not working any more.
• Mouted with other remaining flags, logging is working fine.

3. Unit tests - automation.
4. Integration tests - automation.

[vadlakondaswetha]

In future, if we need anything to log in file-system. We can use the same flag --debug_fuse.

if we want to log anything in gcsfuse, how to log it?

[Prince] As per my understanding, gcsfuse is working right now as a thin connector b/w fuse and gcs. So, most of the logs will be part of these two flags. In some parts of GCSFuse, E.g. ContentCache, logs are written with the default logger, not guarded by any special debug flag. And most of the logs (E.g. auth, stackdriver) in gcsfuse are one time setup log, which are also written with the default logger.
So, I don't think we need another flag to guard gcsfuse related logs unless until we are introduce a complex feature related to caching or some optimisations.