Am 22.08.2014 um 14:25 hat Richard W.M. Jones geschrieben: > > On Mon, Jul 28, 2014 at 04:48:46PM +0800, Hu Tao wrote: > > ping... > > > > All the 6 patches have reviewed-by now. > > > > On Fri, Jul 11, 2014 at 02:09:57PM +0800, Hu Tao wrote: > > > This series adds two preallocation mode to qcow2 and raw: > > > > > > Option preallocation=full preallocates disk space for image by writing > > > zeros to disk, this ensures disk space in any cases. > > > > > > Option preallocation=falloc preallocates disk space by calling > > > posix_fallocate(). This is faster than preallocation=full. > > Sorry if this was discussed before, but why would anyone use > preallocation=full if preallocation=falloc was possible? > > Shouldn't preallocation=full simply use posix_fallocate if it's > available, and fall back to writing zeroes if not?
posix_fallocate() is basically metadata preallocation on the file system level. If any lower levels involve allocations as well, does posix_fallocate() allocate them there? Kevin
