cluster/ec: Provide an option to enable/disable eager lock

Problem: If a fop takes lock, and completes its operation,
it waits for 1 second before releasing the lock. However,
If ec find any lock contention within this time period,
it release the lock immediately before time expires. As we
take lock on first brick, for few operations, like read, it
might happen that discovery of lock contention might take
long time and can degrades the performance.

Solution: Provide an option to enable/disable eager lock.
If eager lock is disabled, lock will be released as soon
as fop completes.

gluster v set <VOLUME NAME> disperse.eager-lock on
gluster v set <VOLUME NAME> disperse.eager-lock off

master-
http://review.gluster.org/13605

Change-Id: I000985a787eba3c190fdcd5981dfbf04e64af166
BUG: 1318965
Signed-off-by: Ashish Pandey <aspandey@redhat.com>
Reviewed-on: http://review.gluster.org/13773
Smoke: Gluster Build System <jenkins@build.gluster.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

3 files changed, 16 insertions, 3 deletions

diff --git a/xlators/cluster/ec/src/ec-common.c b/xlators/cluster/ec/src/ec-common.c
index 8c6ff78c27e..de0e597d124 100644
--- a/xlators/cluster/ec/src/ec-common.c
+++ b/xlators/cluster/ec/src/ec-common.c
@@ -2034,11 +2034,13 @@ void ec_flush_size_version(ec_fop_data_t *fop)
 void ec_lock_reuse(ec_fop_data_t *fop)
 {
     ec_cbk_data_t *cbk;
+    ec_t *ec = NULL;
     int32_t i, count;
     gf_boolean_t release = _gf_false;
-
+    ec = fop->xl->private;
     cbk = fop->answer;
-    if (cbk != NULL) {
+
+    if (ec->eager_lock && cbk != NULL) {
         if (cbk->xdata != NULL) {
             if ((dict_get_int32(cbk->xdata, GLUSTERFS_INODELK_COUNT,
                                 &count) == 0) && (count > 1)) {
@@ -2050,7 +2052,8 @@ void ec_lock_reuse(ec_fop_data_t *fop)
             }
         }
     } else {
-        /* If we haven't get an answer with enough quorum, we always release
+        /* If eager lock is disabled or If we haven't get
+         * an answer with enough quorum, we always release
          * the lock. */
         release = _gf_true;
     }
diff --git a/xlators/cluster/ec/src/ec.c b/xlators/cluster/ec/src/ec.c
index e8acc2303b9..3133962cb4f 100644
--- a/xlators/cluster/ec/src/ec.c
+++ b/xlators/cluster/ec/src/ec.c
@@ -261,6 +261,8 @@ reconfigure (xlator_t *this, dict_t *options)
                           failed);
         GF_OPTION_RECONF ("iam-self-heal-daemon", ec->shd.iamshd, options,
                           bool, failed);
+        GF_OPTION_RECONF ("eager-lock", ec->eager_lock, options,
+                          bool, failed);
         GF_OPTION_RECONF ("background-heals", background_heals, options,
                           uint32, failed);
         GF_OPTION_RECONF ("heal-wait-qlength", heal_wait_qlen, options,
@@ -599,6 +601,7 @@ init (xlator_t *this)
     ec_method_initialize();
     GF_OPTION_INIT ("self-heal-daemon", ec->shd.enabled, bool, failed);
     GF_OPTION_INIT ("iam-self-heal-daemon", ec->shd.iamshd, bool, failed);
+    GF_OPTION_INIT ("eager-lock", ec->eager_lock, bool, failed);
     GF_OPTION_INIT ("background-heals", ec->background_heals, uint32, failed);
     GF_OPTION_INIT ("heal-wait-qlength", ec->heal_wait_qlen, uint32, failed);
     ec_configure_background_heal_opts (ec, ec->background_heals,
@@ -1309,6 +1312,12 @@ struct volume_options options[] =
                      "translator is running as part of self-heal-daemon "
                      "or not."
     },
+    { .key = {"eager-lock"},
+      .type = GF_OPTION_TYPE_BOOL,
+      .default_value = "on",
+      .description = "This option will enable/diable eager lock for"
+                     "disperse volume "
+    },
     { .key = {"background-heals"},
       .type = GF_OPTION_TYPE_INT,
       .min = 0,/*Disabling background heals*/
diff --git a/xlators/cluster/ec/src/ec.h b/xlators/cluster/ec/src/ec.h
index 480125e35d3..49af5c2daf2 100644
--- a/xlators/cluster/ec/src/ec.h
+++ b/xlators/cluster/ec/src/ec.h
@@ -54,6 +54,7 @@ struct _ec
     gf_lock_t         lock;
     gf_timer_t *      timer;
     gf_boolean_t      shutdown;
+    gf_boolean_t      eager_lock;
     uint32_t          background_heals;
     uint32_t          heal_wait_qlen;
     struct list_head  pending_fops;