Veritas™ File System 5.0.1 Programmer's Reference Guide

The restored FCL file can be passed as an argument to vxfs_fcl_open for further
use with the FCL API.
Warning: The reverse name lookup API does not work on the off-host system. The
off-host processing mechanism should only be used when the application can
work with the inode number and generation count, or when it has an independent
method to determine the filenames from the inode number.
Veritas File System and File Change Log upgrade and downgrade
VxFS 4.1 supported only FCL Version 3. VxFS 5.0 supports both FCL Version 3
and 4, with Version 4 as the default. When a system is upgraded from VxFS 4.1
to VxFS 5.0, and the file system has FCL switched on, the existing Version 3 FCL
files remains as is. VxFS 5.0 continues tracking file system changes in the Version
3 FCL exactly as it was done by VxFS 4.1.
A VxFS 4.1 application that directly accesses the FCL file using the read(2) system
call can still continue to work in 5.0 provided that the FCL file is Version 3.
However, you must develop any new applications using the API. The API has
support for both FCL Versions 3 and 4.
If a new application uses the newly added record types in VxFS 5.0 such as file
opens or access information, etc., the FCL needs to be at Version 4.
If you are running applications that still read FCL Version 3 directly, you cannot
upgrade to FCL Version 4 until those applications are rewritten to use the new
API. The API can interpret both Version 3 and Version 4, so applications can be
upgraded to use the API while Version 3 is still in effect.
Converting File Change Log version 3 files to version 4
To convert VCL Version 3 files to Version 4
1
Switch off the FCL.
$ fcladm off mntpt
2
Remove the existing FCL file.
$ fcladm rm mntpt
3
Re-activate with the required version.
$ fcladm [-oversion=4] on mntpt
47File Change Log
Application programming interface for File Change Log