Re: [PATCH] copy: adjust fiemap handling of sparse files

[Pádraig Brady]

On 10/02/11 10:53, Jim Meyering wrote:
> While using --sparse=always is a lot less common,
> it looks like there's room for improvement there, too.
> I.e., we should be able to eliminate all of these
> lseek calls on the output descriptor there, too:
> 
>     $ strace -e lseek cp --sparse=always /tmp/t.f /tmp/t2 2>&1|wc -l
>     16384

True. So merge the "lseeks" in the sparse detection in sparse_copy.
I'll have a look at adding that this evening.
Note we'd only get 1 lseek for the fallocated file above
if the mentioned FIEMAP_EXTENT_UNWRITTEN idea works.

cheers,
Pádraig.