s3:idmap_autorid: use less transactions

reduce the amount of transactions that are mostly unnecessary because no
updates were done, only reads

Autobuild-User: Christian Ambach <ambi@samba.org>
Autobuild-Date: Fri Dec 16 20:18:37 CET 2011 on sn-devel-104

diff --git a/source3/winbindd/idmap_autorid.c b/source3/winbindd/idmap_autorid.c
index 1a88fd4cb84685d50c19d6f9636e04def969a67c..6a39816268d82f73b6228b827d987f114334ade1 100644 (file)
--- a/source3/winbindd/idmap_autorid.c
+++ b/source3/winbindd/idmap_autorid.c
@@ -55,7 +55,7 @@ struct autorid_domain_config {
 /* handle to the tdb storing domain <-> range assignments */
 static struct db_context *autorid_db;
 
-static NTSTATUS idmap_autorid_get_domainrange(struct db_context *db,
+static NTSTATUS idmap_autorid_get_domainrange_action(struct db_context *db,
                                              void *private_data)
 {
        NTSTATUS ret;
@@ -65,71 +65,95 @@ static NTSTATUS idmap_autorid_get_domainrange(struct db_context *db,
 
        cfg = (struct autorid_domain_config *)private_data;
 
-       ret = dbwrap_fetch_uint32(db, cfg->sid, &domainnum);
-       if (!NT_STATUS_IS_OK(ret)) {
-               DEBUG(10, ("Acquiring new range for domain %s\n", cfg->sid));
+       ret = dbwrap_fetch_uint32(db, cfg->sid, &(cfg->domainnum));
 
-               /* fetch the current HWM */
-               ret = dbwrap_fetch_uint32(db, HWM, &hwm);
-               if (!NT_STATUS_IS_OK(ret)) {
-                       DEBUG(1, ("Fatal error while fetching current "
-                                 "HWM value: %s\n", nt_errstr(ret)));
-                       ret = NT_STATUS_INTERNAL_ERROR;
-                       goto error;
-               }
+       if (NT_STATUS_IS_OK(ret)) {
+               /* entry is already present*/
+               return ret;
+       }
 
-               /* do we have a range left? */
-               if (hwm >= cfg->globalcfg->maxranges) {
-                       DEBUG(1, ("No more domain ranges available!\n"));
-                       ret = NT_STATUS_NO_MEMORY;
-                       goto error;
-               }
+       DEBUG(10, ("Acquiring new range for domain %s\n", cfg->sid));
 
-               /* increase the HWM */
-               ret = dbwrap_change_uint32_atomic(db, HWM, &domainnum, 1);
-               if (!NT_STATUS_IS_OK(ret)) {
-                       DEBUG(1, ("Fatal error while fetching a new "
-                                 "domain range value!\n"));
-                       goto error;
-               }
+       /* fetch the current HWM */
+       ret = dbwrap_fetch_uint32(db, HWM, &hwm);
+       if (!NT_STATUS_IS_OK(ret)) {
+               DEBUG(1, ("Fatal error while fetching current "
+                         "HWM value: %s\n", nt_errstr(ret)));
+               ret = NT_STATUS_INTERNAL_ERROR;
+               goto error;
+       }
 
-               /* store away the new mapping in both directions */
-               ret = dbwrap_trans_store_uint32(db, cfg->sid, domainnum);
-               if (!NT_STATUS_IS_OK(ret)) {
-                       DEBUG(1, ("Fatal error while storing new "
-                                 "domain->range assignment!\n"));
-                       goto error;
-               }
+       /* do we have a range left? */
+       if (hwm >= cfg->globalcfg->maxranges) {
+               DEBUG(1, ("No more domain ranges available!\n"));
+               ret = NT_STATUS_NO_MEMORY;
+               goto error;
+       }
 
-               numstr = talloc_asprintf(db, "%u", domainnum);
-               if (!numstr) {
-                       ret = NT_STATUS_NO_MEMORY;
-                       goto error;
-               }
+       /* increase the HWM */
+       ret = dbwrap_change_uint32_atomic(db, HWM, &domainnum, 1);
+       if (!NT_STATUS_IS_OK(ret)) {
+               DEBUG(1, ("Fatal error while fetching a new "
+                         "domain range value!\n"));
+               goto error;
+       }
+
+       /* store away the new mapping in both directions */
+       ret = dbwrap_store_uint32(db, cfg->sid, domainnum);
+       if (!NT_STATUS_IS_OK(ret)) {
+               DEBUG(1, ("Fatal error while storing new "
+                         "domain->range assignment!\n"));
+               goto error;
+       }
+
+       numstr = talloc_asprintf(db, "%u", domainnum);
+       if (!numstr) {
+               ret = NT_STATUS_NO_MEMORY;
+               goto error;
+       }
 
-               ret = dbwrap_trans_store_bystring(db, numstr,
-                               string_term_tdb_data(cfg->sid), TDB_INSERT);
+       ret = dbwrap_store_bystring(db, numstr,
+                       string_term_tdb_data(cfg->sid), TDB_INSERT);
 
-               talloc_free(numstr);
-               if (!NT_STATUS_IS_OK(ret)) {
-                       DEBUG(1, ("Fatal error while storing "
-                                 "new domain->range assignment!\n"));
-                       goto error;
-               }
-               DEBUG(5, ("Acquired new range #%d for domain %s\n",
-                         domainnum, cfg->sid));
+       talloc_free(numstr);
+       if (!NT_STATUS_IS_OK(ret)) {
+               DEBUG(1, ("Fatal error while storing "
+                         "new domain->range assignment!\n"));
+               goto error;
        }
+       DEBUG(5, ("Acquired new range #%d for domain %s\n",
+                 domainnum, cfg->sid));
 
-       DEBUG(10, ("Using range #%d for domain %s\n", domainnum, cfg->sid));
        cfg->domainnum = domainnum;
 
        return NT_STATUS_OK;
 
-      error:
+error:
        return ret;
 
 }
 
+static NTSTATUS idmap_autorid_get_domainrange(struct autorid_domain_config *dom)
+{
+       NTSTATUS ret;
+
+       /*
+        * try to find mapping without locking the database,
+        * if it is not found create a mapping in a transaction
+        */
+       ret = dbwrap_fetch_uint32(autorid_db, dom->sid, &(dom->domainnum));
+
+       if (!NT_STATUS_IS_OK(ret)) {;
+               ret = dbwrap_trans_do(autorid_db,
+                             idmap_autorid_get_domainrange_action, dom);
+       }
+
+       DEBUG(10, ("Using range #%d for domain %s\n", dom->domainnum,
+                  dom->sid));
+
+       return ret;
+}
+
 static NTSTATUS idmap_autorid_id_to_sid(struct autorid_global_config *cfg,
                                        struct id_map *map)
 {
@@ -318,9 +342,7 @@ static NTSTATUS idmap_autorid_sids_to_unixids(struct idmap_domain *dom,
                domaincfg.globalcfg = global;
                sid_to_fstring(domaincfg.sid, &domainsid);
 
-               ret = dbwrap_trans_do(autorid_db,
-                                     idmap_autorid_get_domainrange,
-                                     &domaincfg);
+               ret = idmap_autorid_get_domainrange(&domaincfg);
 
                if (!NT_STATUS_IS_OK(ret)) {
                        DEBUG(3, ("Could not determine range for domain, "
@@ -617,9 +639,8 @@ static NTSTATUS idmap_autorid_allocate_id(struct idmap_domain *dom,
        domaincfg.globalcfg = globalcfg;
        fstrcpy(domaincfg.sid, ALLOC_RANGE);
 
-       ret = dbwrap_trans_do(autorid_db,
-                             idmap_autorid_get_domainrange,
-                             &domaincfg);
+       ret = idmap_autorid_get_domainrange(&domaincfg);
+
        if (!NT_STATUS_IS_OK(ret)) {
                DEBUG(3, ("Could not determine range for allocation pool, "
                          "check previous messages for reason\n"));