Change severity of log entries in sftp-subsys.log

[Bjarke42]

The following log entries from sftp.subsys.log:

2023-09-12 09:00:53,526 ERROR get_fs_path failed: Invalid path characters

another

2023-09-12 09:00:53,526 WARNING lstat filepath/filename: Invalid path characters

Please set those to only being shown if debug is enabled, they serve no purpose to see on a system. They are from a user who does not use the system correctly, that should not reflect as an error on the server, nor a warning with a full printout of the fil.

Just for some perspective, this is the amount i have for this month in the log file:

# grep "ERROR get_fs_path failed:" sftp-subsys.log |wc -l
15317317
# grep ": Invalid path characters" sftp-subsys.log |wc -l
30809002
# wc -l sftp-subsys.log
45424166 sftp-subsys.log

68% of the logfile is these two entries alone, from a user who does not check his replication errors.

[jonasbardino]

While the log volume sounds (too) high I disagree that incorrect use errors are ever irrelevant. When time permits we can look into reducing the verbosity and maybe reduce error to warning, but I don't think changing such logs to debug is the right solution.
Educating users or filtering logs are valid alternatives. Perhaps investigating which invalid path characters it revolves around would be another idea. We are conservative about not allowing characters that may be harmful or cause cross-platform inconsistencies, but are still open to adjusting to allow safe valid use cases.