Re: [Bug-tar] Detection of sparse files is broken on btrfs

[Tim Kientzle]

Quoted from the earlier discussion:

> > One option is if st_blocks == 0 then tar should also check if st_mtime is
> > less than 60s in the past, and if yes then it should call fsync() on the
> > file to flush any unwritten data to disk , or assume the file is not sparse
> > and read the whole file, so that it doesn't incorrectly assume that the file
> > is sparse and skip archiving the file data.

I'm not entirely sure I understand the above.

It sounds like someone is claiming that:

* Archiving programs should know about the *timing* of filesystem 
implementations  (60s here for btrfs, something else for <new filesystem XYZ>?)

* And specifically request the OS to fsync() files before trusting the metadata

Huh?

Tim