Re: [Bug-tar] tar keeps reporting "file changed as we read it" on random files

[Paul Eggert]

On 12/02/2015 01:52 PM, Mark O'Keefe wrote:
> Is the mtime versus ctime security concern still relevant for a directory?

Yes, because applications can set directory mtime values to whatever 
they want, using system calls like utimensat. If an application 
backdates a directory, tar could incorrectly think its contents 
unchanged, and could therefore dump files incorrectly. This can matter 
if tar is being used for incremental backups.

Quite possibly you're right and tar could use yet another option to work 
around this sort of file system misbehavior. But really, the file system 
should get fixed, as tar's not the only program that assumes ctime is 
reliable.