Some of my users have had trouble with software (on Scientific Linux) that cannot list directory contents when accessing an XFS filesystem mounted with the "inode64" option. So I have copied the data to a freshly created XFS filesystem without this option.
Unfortunately during the process of switching round the filesystems I inadvertently mounted the new filesystem briefly with the inode64 option. I noticed the mistake quickly and unmounted it, and I have checked that there are no files with a modification time later than the error occurred.
But is there any way inodes above the 32-bit limit could have been created without this being apparent from file modification times, and is there any way to check this short of listing the entire (6 TB) filesystem recursively and finding the maximum inode value?