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

[Joerg Schilling]

Pavel Raiskup <address@hidden> wrote:

> On Tuesday, January 9, 2018 8:59:06 AM CET Paul Eggert wrote:
> > Pavel Raiskup wrote:
> > > So what about special casing that filesystem, where we can lseek() for
> > > holes anyway?
> > 
> > If we can lseek for holes, then why not just do that?
>
> Checking whether lseek() actually works costs some additional syscalls _per
> sparse_ file;  checking for ST_NBLOCKS() is without this penalty.

Well, star does this since a long time and the penalty is a few microseconds.

"~A