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Re: (ITS#5487) syncprov_findbase must search the backend from the syncrepl search
Rein Tollevik wrote:
> On Wed, 30 Apr 2008, Howard Chu wrote:
>> rein@OpenLDAP.org wrote:
>>> syncprov_findbase() must search the backend saved with the syncrepl
>>> not the one from the operation passed as argument. The backend in the op
>>> argument can be a subordinate database, in which case the search for the
>>> base in
>>> the superior database will fail, and syncrepl consumers will be force to do
>>> a an
>>> unneccessary full refresh of the database.
>>> The patch at the end should fix
>>> this. Note that both fop.o_bd and fop.o_bd->bd_info can be changed by the
>>> overlay_op_walk() call, which is the reason for the long pointer traversal
>>> find the correct bd_info to save and restore.
>> But the overlay_op_walk call is only appropriate when the DB to be searched
>> is the current database, and the current DB is an overlay DB structure.
> Ah, the changing of the BackendDB->bd_info that takes place when
> overlays are called feels like an open pit I manage to fall into every
> time I get close to it... I wish it could be replaced in a future
Agreed, it would have been safer as an Op-specific field, but that would have
caused quite a lot of disruption to all existing backend code.
> A new patch that I hope should fix this is at the end. It always use
> be_search, after putting back the original bd_info if needed. I feel
> that using the generic be_search is better than interfering directly
> with the overlay code as overlay_op_walk does. I also tested for
> SLAP_ISOVERLAY rather than PS_IS_REFRESHING, as that appeared more
> generic to me. But again, I may be totally wrong here. Does this patch
> look better?
SLAP_IS_OVERLAY will never be true here. That flag is only set when the
BackendDB being tested is a local copy of a real BackendDB structure. The
structure referenced in s_op is always a real BackendDB.
In fact, if you're always going to use s_op and be_search, there's no further
work needed, because the regular overlay infrastructure will always make a new
local BackendDB copy itself. (And of course, some of that would be wasted
effort, which is why the original code uses overlay_op_walk. Since op->o_bd is
already an overlay DB, there's no need to make yet another copy for the
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/