cluster/dht: Optimize readdirp calls in DHT

Bring in option which is supported by posix xlator
to filter out directory's entries from being returned.
DHT would now request non-first subvols to filter out
directory entries.

dht xlator-option readdir-optimize will enable this
optimization

Change-Id: Ibf99f1bef501f285ff44a1cecfbebee9e16063b6
BUG: 838199
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.com/3806
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

3 files changed, 35 insertions, 1 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 5da0c10bba2..ade05f38d3c 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -2766,6 +2766,7 @@ dht_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int op_ret,
         dht_layout_t *layout = 0;
         dht_conf_t   *conf   = NULL;
         xlator_t     *subvol = 0;
+        int           ret = 0;
 
         INIT_LIST_HEAD (&entries.list);
         prev = cookie;
@@ -2843,6 +2844,16 @@ done:
                         goto unwind;
                 }
 
+		if (conf->readdir_optimize == _gf_true) {
+                        if (next_subvol != dht_first_up_subvol (this)) {
+                                ret = dict_set_int32 (local->xattr,
+                                                      GF_READDIR_SKIP_DIRS, 1);
+                                if (ret)
+                                        gf_log (this->name, GF_LOG_ERROR,
+					         "dict set failed");
+		        }
+                }
+
                 STACK_WIND (frame, dht_readdirp_cbk,
                             next_subvol, next_subvol->fops->readdirp,
                             local->fd, local->size, next_offset,
@@ -2968,11 +2979,14 @@ dht_do_readdir (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
         xlator_t     *xvol = NULL;
         off_t         xoff = 0;
         int           ret = 0;
+        dht_conf_t   *conf = NULL;
 
         VALIDATE_OR_GOTO (frame, err);
         VALIDATE_OR_GOTO (this, err);
         VALIDATE_OR_GOTO (fd, err);
 
+        conf = this->private;
+
         local = dht_local_init (frame, NULL, NULL, whichop);
         if (!local) {
                 op_errno = ENOMEM;
@@ -3000,6 +3014,16 @@ dht_do_readdir (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
                                 gf_log (this->name, GF_LOG_WARNING,
                                         "failed to set 'glusterfs.dht.linkto'"
                                         " key");
+			if (conf->readdir_optimize == _gf_true) {
+                                if (xvol != dht_first_up_subvol (this)) {
+				        ret = dict_set_int32 (local->xattr,
+			                               GF_READDIR_SKIP_DIRS, 1);
+				        if (ret)
+					        gf_log (this->name,
+                                                        GF_LOG_ERROR,
+						        "Dict set failed");
+                                }
+			}
                 }
 
                 STACK_WIND (frame, dht_readdirp_cbk, xvol, xvol->fops->readdirp,
diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index 9f7723fdbde..da83967e76d 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -246,6 +246,10 @@ struct dht_conf {
 
         /* defrag related */
         gf_defrag_info_t *defrag;
+
+        /* Request to filter directory entries in readdir request */
+
+        gf_boolean_t    readdir_optimize;
 };
 typedef struct dht_conf dht_conf_t;
 
diff --git a/xlators/cluster/dht/src/dht.c b/xlators/cluster/dht/src/dht.c
index e3930e2af3f..68a8efcde88 100644
--- a/xlators/cluster/dht/src/dht.c
+++ b/xlators/cluster/dht/src/dht.c
@@ -331,7 +331,8 @@ reconfigure (xlator_t *this, dict_t *options)
                           percent, out);
         GF_OPTION_RECONF ("directory-layout-spread", conf->dir_spread_cnt,
                           options, uint32, out);
-
+        GF_OPTION_RECONF ("readdir-optimize", conf->readdir_optimize, options,
+                          bool, out);
         if (dict_get_str (options, "decommissioned-bricks", &temp_str) == 0) {
                 ret = dht_parse_decommissioned_bricks (this, conf, temp_str);
                 if (ret == -1)
@@ -431,6 +432,7 @@ init (xlator_t *this)
 
         GF_OPTION_INIT ("assert-no-child-down", conf->assert_no_child_down,
                         bool, err);
+        GF_OPTION_INIT ("readdir-optimize", conf->readdir_optimize, bool, err);
 
         ret = dht_init_subvolumes (this, conf);
         if (ret == -1) {
@@ -593,6 +595,10 @@ struct volume_options options[] = {
         { .key = {"node-uuid"},
           .type = GF_OPTION_TYPE_STR,
         },
+        { .key = {"readdir-optimize"},
+          .type = GF_OPTION_TYPE_BOOL,
+          .default_value = "off",
+        },
 
         { .key  = {NULL} },
 };