rein@OpenLDAP.org wrote:

Full_Name: Rein Tollevik Version: CVS head OS: URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (81.93.160.250) Submitted by: rein

syncprov_findbase() must search the backend saved with the syncrepl operation, 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.

OK.

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 to 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.

Your patch causes fc->fss->s_op->o_bd's bd_info pointer to change, which is not allowed. That's in the original backendDB, which must be treated as read-only since multiple threads may be accessing it. The correct approach here is to use a new local backendDB variable, copy the s_op->o_bd into it, and then just do a regular be_search invocation instead of using overlay_op_walk.

But, this patch must not take effect on the first call to syncprov_findbase (which occurred in syncprov_op_search) - in that case, the current code is correct. So, you need to tweak things based on whether (s_flags & PS_IS_REFRESHING) is true or not - if true, this is the first search, and it should use the original code. Else, it must use be_search.

Rein Tollevik Basefarm AS

diff -u OpenLDAP/servers/slapd/overlays/syncprov.c:1.1.1.18 OpenLDAP/servers/slapd/overlays/syncprov.c:1.19 --- OpenLDAP/servers/slapd/overlays/syncprov.c:1.1.1.18 Wed Apr 30 13:17:58 2008 +++ OpenLDAP/servers/slapd/overlays/syncprov.c Wed Apr 30 19:34:00 2008 @@ -404,7 +404,7 @@ slap_callback cb = {0}; Operation fop; SlapReply frs = { REP_RESULT };

• BackendInfo *bi;
  

• BackendInfo *bi = fc->fss->s_op->o_bd->bd_info;
  

  int rc;

  fc->fss->s_flags ^= PS_FIND_BASE;

@@ -413,10 +413,8 @@ fop = *fc->fss->s_op;

fop.o_hdr = op->o_hdr;

• fop.o_bd = op->o_bd;
  

  fop.o_time = op->o_time; fop.o_tincr = op->o_tincr;

• bi = op->o_bd->bd_info;
  
  

  cb.sc_response = findbase_cb; cb.sc_private = fc;

@@ -435,7 +433,7 @@ fop.ors_filterstr = generic_filterstr;

rc = overlay_op_walk(&fop,&frs, op_search, on->on_info, on );

• op->o_bd->bd_info = bi;
  

• fc->fss->s_op->o_bd->bd_info = bi;
  

  } else { ldap_pvt_thread_mutex_unlock(&fc->fss->s_mutex ); fc->fbase = 1;