[OpenAFS] dropbox semantics ("irl")

Adam Megacz megacz@cs.berkeley.edu
Wed, 30 May 2007 10:25:49 -0700

I'm a bit confused about how "dropbox semantics" (that is, "irl") work.

As I understand it, "irl" gives the expected dropbox behavior because
newly-created files are given an "owner" equal to the pts identity of
the user who created the file.  From that point on, the special
exception "owner may read+write a file with only 'i' acl" lets the
owner populate the file with data.

But, if this is the case, what prevents the owner of the file from
modifying it after closing the file? (I checked, they can't, but I
don't understand what part of the protocol enforces this)

I thought that -- at the protocol/fileserver level -- there was no
RXAFS_CloseFile call.  In other words, how does the server know when
the client has executed a close() call so it can prohibit any
RXAFS_StoreData's that come after it?  Doesn't a close() look the same
as an fsync() from the fileserver's perspective?

Thanks for any clues!  I'll augment the FAQ entry on dementia.org with
whatever I learn.

  - a

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