> > Certainly, but tar isn't going to remember all the inode numbers. > > Even if you solve the storage requirements (not impossible) it would > > have to do (4e9^2)/2=8e18 comparisons, which computers don't have > > enough CPU power just yet. > > It is remembering all inode numbers with nlink > 1 and many other tools > are remembering all directory inode numbers (see my other post on this > topic). Don't you mean they are remembering all the inode numbers of the directories _above_ the one they are currently working on? I'm quite sure they aren't remembering all the directories they have processed. > It of course doesn't compare each number with all others, it is > using hashing. Yes, I didn't think of that. > > It doesn't matter if there are collisions within the filesystem, as > > long as there are no collisions between the set of files an > > application is working on at the same time. > > --- that are all files in case of backup. No, it's usually working with a _single_ file at a time. It will remember inode numbers of files with nlink > 1, but it won't remember all the other inode numbers. You could have a filesystem with 4billion files, each one having two links. Not a likely scenario though. Miklos - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
