libglusterfsclient: Move DHT root-lookup workaround to init

The workaround for the DHT requirement for a lookup on /
needs to be done only once when the xlator graph is inited.
Doing it on every path's lookup results in a major performance
penalty when using distribute subvolumes upwards of 16, as reported
by Avati.

Ref: bug 152

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 152 (libglusterfsclient: DHT workaround is a major performance bottleneck)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=152

1 files changed, 12 insertions, 0 deletions

diff --git a/libglusterfsclient/src/libglusterfsclient.c b/libglusterfsclient/src/libglusterfsclient.c
index 0133126cd48..c456eed0719 100755
--- a/libglusterfsclient/src/libglusterfsclient.c
+++ b/libglusterfsclient/src/libglusterfsclient.c
@@ -961,6 +961,7 @@ glusterfs_init (glusterfs_init_params_t *init_ctx)
         int32_t ret = 0;
         struct rlimit lim;
 	uint32_t xl_count = 0;
+        loc_t       new_loc = {0, };
 
         if (!init_ctx || (!init_ctx->specfile && !init_ctx->specfp)) {
                 errno = EINVAL;
@@ -1261,6 +1262,17 @@ glusterfs_init (glusterfs_init_params_t *init_ctx)
         }
         pthread_mutex_unlock (&priv->lock);
 
+        /* workaround for xlators like dht which require lookup to be sent
+         * on / */
+        libgf_client_loc_fill (&new_loc, ctx, 1, 0, "/");
+        ret = libgf_client_lookup (ctx, &new_loc, NULL, NULL, NULL);
+        if (ret == -1) {
+                gf_log ("libglusterfsclient", GF_LOG_ERROR, "lookup of /"
+                        " failed");
+                return NULL;
+        }
+        libgf_client_loc_wipe (&new_loc);
+
 	first_init = 0;
  
         return ctx;