fix: only logging when level permits it on Windows

[Piloalucard]

Summary of changes

This pull request includes following changes or fixes.

Description

On Windows platform, logs of LTFS were not properly set up, every message is logged causing a performance issue when using LTFS with logs enabled. To fix this, a conditional was added to log only messages permitted by the log level set.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have confirmed my fix is effective or that my feature works

[vandelvan]

LGTM! Thank you!

[XV02]

GTG!

[Piloalucard]

Test

1. Before fix (Debug messages printed even the log level is INFO, write performance affected)

PS C:\Program Files\IBM\LTFS> .\ltfs.exe -o changer_devname=0.0.20.1 L
LTFS61259I Sync type is "time", Sync time is 300 sec
LTFS61509I Set trace level in library (LTFS_INFO)
LTFS61206I LTFS starting. Drive:L, (Dec  9 2025 12:41:16) log level 2
LTFS17085I Plugin: Loading "scsilib" tape backend.
LTFS17085I Plugin: Loading "unified" iosched backend.
LTFS17085I Plugin: Loading "scsilib" changer backend.
LTFS17085I Plugin: Loading "memory" crepos backend.
LTFS11593I LTFS starts with a ILAN license version 2.4.8.2.
LTFS62611I Opening a device through scsilib driver (2ed5e5c0h).
LTFS62553D scsilib: scsiExecCDB(12h):.
LTFS62554D scsilib: scsiExecCDB(12h): rc=0 SysErr=0 SCSIStatus=00h sense=00h/0000h:32.
LTFS62553D scsilib: scsiExecCDB(12h):.
LTFS62554D scsilib: scsiExecCDB(12h): rc=0 SysErr=0 SCSIStatus=00h sense=00h/0000h:32.
LTFS62612D scsi0:0.20.1 is opened.
LTFS62613I Changer serial is 55L3A78014R3LL01.

2. After fix (No debug messages because of level, no write performance issues)

PS C:\Program Files\ibm\LTFS> .\ltfs.exe -o changer_devname=5.0.0.1 L
LTFS61259I Sync type is "time", Sync time is 300 sec
LTFS61509I Set trace level in library (LTFS_INFO)
LTFS61206I LTFS starting. Drive:L, (Feb  6 2026 14:53:36) log level 2
LTFS17085I Plugin: Loading "scsilib" tape backend.
LTFS17085I Plugin: Loading "unified" iosched backend.
LTFS17085I Plugin: Loading "scsilib" changer backend.
LTFS17085I Plugin: Loading "memory" crepos backend.
LTFS11593I LTFS starts with a ILAN license version 2.4.8.
LTFS62611I Opening a device through scsilib driver (67e37370h).
LTFS62613I Changer serial is 55L3A78014R3LL02.
LTFS62160I Drive serial is 117193D065.
LTFS17160I Maximum device block size is 524288.
LTFS61509I Set trace level in library (LTFS_INFO)
LTFS11545I Rebuilding the cartridge inventory.
LTFS11627I Getting Inventory - 55L3A78014R3LL02.
LTFS11629I Aqcuireing MoveLock - 55L3A78014R3LL02.
LTFS11630I Aqcuired Move Lock (3) - 55L3A78014R3LL02.
LTFS11628I Got Inventory - 55L3A78014R3LL02.
LTFS11637I Reset the cartridge link against the drive 117193D065.
LTFS11571I State of tape 'FC0541L8' in slot 0x1 is changed from 'INIT' to 'NOT_MOUNTED_YET'.
LTFS11635I Link the drive 117193D065 to the cartridge FC0541L8.
LTFS11571I State of tape 'CLN156L1' in slot 0x3ea is changed from 'INIT' to 'NON_SUPPORTED_TAPE'.
LTFS11720I Built the cartridge inventory (0).
LTFS11774I Starting volume cache cleaning.
LTFS11775I Volume cache cleaning is finished
LTFS10005E Null argument (priv) to dcache_get_workdir.
LTFS11776I Starting volume cache load.
LTFS11777I Loaded required volume caches.
LTFS14708I LTFS admin server version 2 is starting on port 7600.
LTFS61280I Symbolic link type is (posix)
LTFS61237I Read-only directory mode is Windows