[tahoe-dev] [tahoe-lafs] #956: embed security metadata in parent directory

[tahoe-lafs]

#956: embed security metadata in parent directory
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 Reporter:  zooko                                                   |           Owner:           
     Type:  defect                                                  |          Status:  new      
 Priority:  major                                                   |       Milestone:  undecided
Component:  code-dirnodes                                           |         Version:  1.6.0    
 Keywords:  mutable newcaps newurls metadata forward-compatibility  |   Launchpad_bug:           
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Changes (by davidsarah):

  * keywords:  mutable newcaps newurls metadata => mutable newcaps newurls
               metadata forward-compatibility


Comment:

 Replying to [ticket:956 zooko]:
 > A "highest known version number" for a mutable file or directory, which
 according to #955 could be stored in a client to prevent that client from
 perceiving a rollback could ''also'' be stored in a parent directory which
 links to that mutable file or directory, ...

 This can only be done when the client is writing to the directory anyway,
 since it might cause spurious !UncoordinatedWriteErrors to perform
 directory writes that haven't been explicitly requested. Whenever we do
 write a directory, however, we can write the last-known-version for each
 of its children.

 There is going to be a compatibility problem with doing this, since we
 don't (as far as I can see) have anywhere in the directory format to
 encode new fields that will be ignored by old clients. This will also be a
 problem with several other proposed features, including deep-verify caps
 as described in #308, and extensible directories suggested as part of
 #959.

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Ticket URL: <http://allmydata.org/trac/tahoe/ticket/956#comment:2>
tahoe-lafs <http://allmydata.org>
secure decentralized file storage grid