Re: [fuse-devel] delta filesystem prototype

[hooanon05@yahoo.co.jp]

Goswin von Brederlow:
> hooanon05@yahoo.co.jp writes:
	::
> > When a user writes something to the file after unlink+rmdir, where can
> > deltafs copyup? At least in the current implementation, there is no
> > place for it.
	:::
> In the delta branch create a meta/ and files/ directory. In the meta/
> directory you keep whiteout files and stat updates. In files/ you
> store only changes in the file data itself.
> 
> So "rm foo/bar/baz" will create meta/foo/bar/baz.whiteout. Then "echo
> blafase >>foo/bar/baz" first searches for a file to copy-up, sees the
> meta/foo/bar/baz.whiteout and knows the file was deleted. It then
> creates a new files/foo/bar/baz. It might have to copy-up foo and
> foo/bar for that though.

??
What I am pointing out is systemcall level operation instead of command
level.
In your example (or implementation approach), can deltafs successfully
operate "write(2) to and read(2) from foo/bar/baz" after "rm -r foo/bar"?

(from my previous mail)
----------------------------------------------------------------------
- open a file on deltafs
- unlink it
- rmdir its parent
- write or fchmod to it
- rewind+read or mmap+read from the opened file
- cat it be read correctly?
----------------------------------------------------------------------


J. R. Okajima