On 09/13/10 10:35, Michal Svoboda wrote: > Paul Eggert wrote: >> There are applications where it's important that the metadata be >> consistent with the data: for example, it could be that the data >> contain time stamps, which should always predate the ctime, and >> if the tar image contains data with timestamps after the ctime, >> then the tar image is inconsistent. > > How can this happen without modifying the data?
My scenario was assuming that some other process modified the data. But that is a scenario of concern. User processes can set the mtime after modifying the data (this is normal, for applications such as cp -p) so tar cannot trust the mtime here. In contrast, ctime is more trustable: in most environments user processes can't set the ctime to arbitrary values. That is why tar should use ctime here.
