cluster/ec: Add/Modify description for eager-lock option

This patch provides description for disperse.eager-lock
option for disperse volume.

It also modifies the description for cluster.eager-lock
option to indicate that this option is only for replica
volume.

Change-Id: Ie73298947fcaaa6aaf825978bc2d27ceaff386d2
BUG: 1327171
Signed-off-by: Ashish Pandey <aspandey@redhat.com>
Reviewed-on: http://review.gluster.org/13999
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

2 files changed, 17 insertions, 6 deletions

diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index 348012ff2ad..15e4ec41891 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -782,16 +782,17 @@ struct volume_options options[] = {
         { .key = {"eager-lock"},
           .type = GF_OPTION_TYPE_BOOL,
           .default_value = "on",
-          .description = "Lock phase of a transaction has two sub-phases. "
+          .description = "Enable/Disable eager lock for replica volume. "
+                         "Lock phase of a transaction has two sub-phases. "
                          "First is an attempt to acquire locks in parallel by "
                          "broadcasting non-blocking lock requests. If lock "
                          "acquisition fails on any server, then the held locks "
-                         "are unlocked and revert to a blocking locked mode "
+                         "are unlocked and we revert to a blocking locks mode "
                          "sequentially on one server after another.  If this "
                          "option is enabled the initial broadcasting lock "
-                         "request attempt to acquire lock on the entire file. "
+                         "request attempts to acquire a full lock on the entire file. "
                          "If this fails, we revert back to the sequential "
-                         "\"regional\" blocking lock as before. In the case "
+                         "\"regional\" blocking locks as before. In the case "
                          "where such an \"eager\" lock is granted in the "
                          "non-blocking phase, it gives rise to an opportunity "
                          "for optimization. i.e, if the next write transaction "
diff --git a/xlators/cluster/ec/src/ec.c b/xlators/cluster/ec/src/ec.c
index 1d53981303a..ab26e882a2e 100644
--- a/xlators/cluster/ec/src/ec.c
+++ b/xlators/cluster/ec/src/ec.c
@@ -1327,8 +1327,18 @@ struct volume_options options[] =
     { .key = {"eager-lock"},
       .type = GF_OPTION_TYPE_BOOL,
       .default_value = "on",
-      .description = "This option will enable/diable eager lock for"
-                     "disperse volume "
+      .description = "Enable/Disable eager lock for disperse volume. "
+                     "If a fop takes a lock and completes its operation, "
+                     "it waits for next 1 second before releasing the lock, "
+                     "to see if the lock can be reused for next fop from "
+                     "the same client. If ec finds any lock contention within "
+                     "1 second it releases the lock immediately before time "
+                     "expires. This improves the performance of file operations."
+                     "However, as it takes lock on first brick, for few operations "
+                     "like read, discovery of lock contention might take long time "
+                     "and can actually degrade the performance. "
+                     "If eager lock is disabled, lock will be released as soon as fop "
+                     "completes. "
     },
     { .key = {"background-heals"},
       .type = GF_OPTION_TYPE_INT,