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

[Joerg Schilling]

Pavel Raiskup <address@hidden> wrote:

> Well, I now recalled somehow relevant Red Hat bug, sorry I have not
> mentioned it before:
>   https://bugzilla.redhat.com/show_bug.cgi?id=757557
>
> CC'ing fs-devel:  The question is whether that ^^^^ is not a bug in
> filesystem ??? whether filesystem should not _always_ return to fstat()
> block count at least 1 if there are at least some data (even if these data
> are inlined in inode)?  Just for catching the context, this thread starts
> here: http://lists.gnu.org/archive/html/bug-tar/2013-10/msg00030.html
>
> If that is not a bug in fs, is there possible to detect that particular
> file is completely sparse?

In September 2004 I defined the SEEK_HOLE/SEEK_DATA interface together with 
Jeff Bonwick. I believe that we should require that all OS that include 
filesystems that return nblocks == 0 with data in file need to implement
SEEK_HOLE/SEEK_DATA.

Jörg

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