On Thu, Jun 17, 2010 at 10:32:09PM +0200, Alex Riesen wrote:
Whiteouts and fallthrus go away when a directory is deleted. So, "rm
-rf /trash/" will actually free up disk space. You can also move the
files you want to keep to a temp directory, rmdir the old one, and
move that dir back.
Unfortunately, union mounts runs into a lot of bizarre ENOSPC
problems. But in the degenerate case in which you delete every single
file from the lower layer file system, that information will take up
only one whiteout per top-level subdir. You don't keep whiteouts for
anything below a deleted directory.
Any union mount utilities would be distributed as part of the normal
file system utilities package.
Yeah, unlinkat() looks promising.