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[Brian Rosmaita <rosmaita.fossdev@xxxxxxxxx>]

This was addressed by Change-Id:
I593ad2d3c7402c4fb87a475c8d44060baed5ff69


** Changed in: glance
   Importance: Undecided => Low

** Changed in: glance
       Status: New => Fix Released

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https://bugs.launchpad.net/bugs/1648111

Title:
      Restrict location updates to active, queued images

Status in Glance:
  Fix Released

Bug description:
  https://review.openstack.org/366995
  Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.
  Your project "openstack/glance" is set up so that we directly report the documentation bugs against it. If this needs changing, the docimpact-group option needs to be added for the project. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

  commit 4ac8adbccc2b7bbef3d53f9141079c48f9c768f4
  Author: Nikhil Komawar <nik.komawar@xxxxxxxxx>
  Date:   Wed Sep 7 17:29:41 2016 -0400

      Restrict location updates to active, queued images
      
      Currently image location updates (removing, replacing) are permitted for
      images even if their state is not ``active``.
      
      This need is to:
       * Prevent the replacement of image locations of images that are not
         ``active`` or ``queued`` by returning a Conflict Error
          (409 response code).
       * Prevent removal of image locations of images that are not ``active``
         by returning a Conflict Error (409 response code).
      
      Changing of image locations when the image state is not ``active`` can
      result in bad experiences for the users.
       *  If one tries to change or remove the location for an image while it
          is in ``saving`` state, Glance would be trying to write data to a
          previously saved location while the user updates the custom
          location. This results in a race condition.
       *  For images that are in ``queued`` state and no image data has been
          uploaded yet, there is no need for an image location to be
          removed and permitting users to remove the image
          location can result in a bad experience. However users can be
          allowed to replace the image location to maintain backward
          compatibility and also because replacing could mean replacing an
          empty location by a non-empty image location.
      *   For images in ``deactivated`` state, it is essential that image
          locations are not updated as it does not abide with the purpose of
          the image state being set to ``deactivated`` and may cause security
          concerns.
      
      This commit introduces the following change in behavior:
        * If an image is in ``active`` state, removing/replacing the custom
          locations on that image will be allowed so there is no change in
          behavior for this case.
        * If an image is in ``saving`` or ``deactivated``, the status of
          that image will be checked while trying to replace/remove the custom
          location and a HTTP 409 Conflict status will be returned in response
          to the user.
        * If an image is in ``queued`` state, removing the custom
          image location will not be permitted as an image in queued status
          should not have any location associated with it. Replacing of location
          may be permitted here though.
        * If an image is in ``deleted`` or ``pending_delete`` state, a HTTP
          409 Conflict status will be returned, if that image is visible to
          the user (in case of admins). Otherwise, the location cannot be
          removed/replaced anyway.  Please note ``pending_delete`` is another
          form of the ``deleted`` status and behavior in either case should be
          expected to be same.
        * If an image is in ``killed`` status, a HTTP 409 Conflict status will
          be returned.
      
      TODO:
      Atomicity is required such that glance permits removal/replacement of
      image locations on certain permissible image transition states handling
      the race conditions like:
        * In case where the status of the image is ``saving`` and it
          has just moved to ```active`` status, ideally removing/replacing
          custom location should be allowed. However, due to lack of
          atomicity in setting image status glance will ignore setting the
          location and a 409 will be returned.
        * In case where the status of the image is ``deactivated`` and it
          has just been moved to ``active`` status, ideally
          removing/replacing custom location should be allowed. Again, due
          to lack of atomicity in setting image status glance will ignore
          the request and a 409 will be returned.
        * In case where the status of the image is ``active`` and it has
          just been moved to ``deactivated`` status, due to lack of
          atomicity in setting image status, glance may remove/replace
          the location on that image.
        * In case where the status of the image is ``queued`` and it has
          just been moved to ``saving`` status, due to lack of atomicity
          in setting image status, glance may replace the location for
          that image.
        * In case where the status of the image is ``active`` and location
          is attempted to be set on it, and at that point if the image goes
          into ``deleted``, ``pending_delete`` or ``killed`` status, then the
          user must get a HTTP 409 Conflict status. However due to lack of
          atomicity in setting the image status, the location may get updated.
      
      NOTE:
      This commit ensures that removal of image locations
      is not allowed for an image in any state except ``active`` and
      replacement of an image location is not allowed except for ``active``
      and ``queued`` images.
      Further work is required on the atomicity of glance to accommodate
      location updates in cases where the images would be undergoing state
      changes.
      
      Impacts:
      APIImpact
      DocImpact
      
      Credits:
      This commit message contains text and information from the commit
      message for: https://review.openstack.org/#/c/324012/
      co authored by Nikhil Komawar <nik.komawar@xxxxxxxxx>.
      
      Co-Authored-By: Nikhil Komawar <nik.komawar@xxxxxxxxx>
      Co-Authored-By: Dharini Chandrasekar <dharini.chandrasekar@xxxxxxxxx>
      
      Lite-Spec: https://review.openstack.org/#/c/368192/
      Closes-Bug: 1622016
      
      Change-Id: Ic24cf8234599a32add1cb9f294f902e497d885e0

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