What you describe is not unusual. Over long periods of time a filesystem may well develop inconsistencies that fsck will pick up and correct. However, even if these inconsistencies are not...
One thing that comes to my mind is: Did you use sync before umounting or before using fsck ( and after...)? If not, how can you be sure you are not seeing side effects of some cache somewhere?
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The mountpoint itself, before its mounted, what permissions should it have? Probably root, and read-only to everything else. You don't want the mountpoint to be...
sudo when prefixing a pipeline only applies to the first command. cpio need root or at least the RBAC privileges required to set owners, stick-bits and similar sensitive actions.
You can use...