Am 22.08.2014 um 17:34 hat Richard W.M. Jones geschrieben: > On Fri, Aug 22, 2014 at 05:22:33PM +0200, Kevin Wolf wrote: > > It's still useful because it happens to reduce the overhead in most > > implementations and it's a relatively quick operation, but the best way > > I know of to actually _fully_ preallocate is still writing zeros. Which > > of the two the user wants, is a decision that qemu can't make for them. > > This is a difficult situation. Possibly the choice is between > > - efficiently make the file fully allocated, that works in the vast > majority of cases, but don't go crazy (ie. fallocate) > > - really really try as hard as possible to make sure that future > allocations will never fail (ie. write random non-zero data to the > file) > > Note that neither of these is the preallocation=... option as > specified in this patch.
Isn't the first one exactly preallocation=falloc and the second is preallocation=full, except that we're not writing non-zero blocks? (And probably shouldn't, because that would change the content.) Kevin
