Re: [Qemu-devel] copy on write-but-no-change

2007-09-10 Thread Rob Landley
On Friday 07 September 2007 10:40:15 am Luke -Jr wrote: > I don't believe it's possible to make holes in sparse files explicitly. > The libc/OS only support it transparently when you jump to the end of a > file and begin writing there. Actually, I believe it should finally show up in the 2.6.23 ke

Re: [Qemu-devel] copy on write-but-no-change

2007-09-07 Thread Luke -Jr
On Thursday 06 September 2007, Lapo Luchini wrote: > I noticed that cow adds space also if the written data is the same as > the one it was there already. > Is there a reason why checking it would be bad/difficult/slow/other? > Simply no one had the will to code the check? Simply that your operati

[Qemu-devel] copy on write-but-no-change

2007-09-07 Thread Lapo Luchini
I noticed that cow adds space also if the written data is the same as the one it was there already. Is there a reason why checking it would be bad/difficult/slow/other? Simply no one had the will to code the check? I ask because for shrinking drives I usually create big zero-filled files... and th