Re: [Gluster-devel] Handling EOBs in CloudFS

[Jeff Darcy]

On Fri, 15 Jul 2011 13:13:22 -0400
Devon Miller <address@hidden> wrote:

> Re: Approach 1
> Is there a way for process B to use file locking (or some other
> mechanism) such that it could be guaranteed a consistent view of F?

It shouldn't need to.  With either approach, the encryption translator
(actually a partner translator on the server side) is responsible for
providing any serialization necessary to prevent clients from seeing
intermediate states in the middle of a write.  With approach 1, this
includes the state where the file has been extended but the pad bytes
have not yet been moved into an xattr.  With approach 2, this includes
the state where an extending write has been issued but its result is
not yet known - so that it would be invalid to issue the setxattr to
persist the true EOF.  Much of this is covered in

        http://cloudfs.org/dist/design.md

That's the document which had previously been posted on cloudfs-devel,
and to which Edward was responding.  I apologize for his attempt to
continue the discussion on another list without providing appropriate
context.