[Ocfs2-devel] [PATCH 1/3] fs: Document the reflink(2) system call.

[jim owens]

jim owens wrote:
> 
> 1) "snapfile" - Joel's reflink(2) design.
> 2) "cowfilecopy" - Ted's/Jamie's kernel cp.
> 
> could be 1 syscall with a "preserve" flag that requires CAP_FCHOWN.

No disagreement must mean the mail isn't getting through :)

So on to the last turd in the punch bowl,  quota and du rules:

Both snapfile and cowfilecopy:

- must not allow their use to cheat to exceed the user's quota

- would best serve if only the actual disk non-shared space was counted

But we know not all filesystems will be able to change their
on-disk data structures and efficiently count only non-shared.

So I suggest this is the rule:

Quota accounting and disk space used for the original file will
be as if there were 0 reflinks.  Quota accounting and disk space
reported for the new reflink file is filesystem specific and may
or may not include shared disk space.

jim