Re: [Bug-tar] --sparse is broken on filesystems where small files may have zero blocks

[Pavel Raiskup]

> To be clear, I can see that the fix to ST_IS_SPARSE should cause
> dump_regular_file to be called instead of sparse_dump_file, but I still
> wonder if it is wise to leave this logic in place.  At the very last,
> I think a comment would be helpful to explain that this test is valid
> only because ST_IS_SPARSE has already succeeded.

At least for the check for zero blocks in sparse file:  It is intentional
because it makes the processing of completely sparse files to be done in
constant time (try to archive 'file' from `truncate -s 10G file`).  This
could be documented possibly.  Otherwise, I would not say that there is
unclear that sparse_dump_file is supposed to be called only against real
sparse files.