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Re: (ITS#4184) Lockup when moding one particular entry

Pierangelo Masarati wrote:
On Fri, 2005-12-16 at 17:36 +0000, ando@sys-net.it wrote:
I've just fixed it in a rather inelegant manner in HEAD. Please check
(the same test I just posted should do the trick).

I'm a bit uncomfortable with this fix (backend.c 1.358), because sooner or later the same issue could surf again. I think the o_private approach may be too error prone, as backends and mostly overlays proliferate. It __should__ be strengthened. One possibility is to revert to the use of the ldap_pvt_thread_pool_{g,s}etkey() approach; this may require some changes inside back-bdb for the case at hand, and it would only solve the issue of separating per-backend private data. It would not address the specific issue of this ITS, ITS#4184, because different instances of the same backend are accessing the same type of private data for the same thread, so we should also provide a mechanism to augment the key with the database instance; e.g. we should use a struct berval instead of a pointer as key, and do something like

void *ptr[2];
struct berval key;

key.bv_val = ptr;
key.bv_len = sizeof(ptr);

ptr[0] = unique_key; // identifies the type
ptr[1] = be->be_private; // identifies the instance

and ldap_pvt_thread_pool_{g,s}etkey() should do a
bvmatch() on this key.

Or, we could add a(n optional) 2 level ldap_pvt_thread_pool_{g,s}etkey()
with two keys; for the first one, that identifies the type, the current
container would be accessed, but each entry would actually be another
container that is accessed with the second key, which identifies the

I still prefer this solution: http://www.openldap.org/lists/openldap-devel/200510/msg00063.html

As for two-level thread_pool keys, the approach I used previously in back-bdb was to use the be_private pointer as a key, and to use (pointer+1), (pointer+2) etc. for other keys related to the same backend.

 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/