cluster/afr: Make read child match check in afr optionalv3.5.4beta1

        Backport of: http://review.gluster.org/#/c/9917

Having this particular check which was introduced by
commit bb2df4e63fa8a5d65f18b4a5efc757e8d475fbff causes a drop in
performance in readdirp. So the behavior is made configurable with this
patch.

Change-Id: I9012a6bb955229a0cbb48f06e4e2edc0782dfead
BUG: 1202675
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-on: http://review.gluster.org/9924
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index c020cbccac5..0739d0de93b 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -193,6 +193,8 @@ reconfigure (xlator_t *this, dict_t *options)
                           bool, out);
         GF_OPTION_RECONF ("ensure-durability", priv->ensure_durability, options,
                           bool, out);
+        GF_OPTION_RECONF ("consistent-metadata", priv->consistent_metadata,
+                          options, bool, out);
         priv->did_discovery = _gf_false;
 
         ret = 0;
@@ -339,6 +341,8 @@ init (xlator_t *this)
         GF_OPTION_INIT ("readdir-failover", priv->readdir_failover, bool, out);
         GF_OPTION_INIT ("ensure-durability", priv->ensure_durability, bool,
                         out);
+        GF_OPTION_INIT ("consistent-metadata", priv->consistent_metadata, bool,
+                        out);
 
         priv->wait_count = 1;
 
@@ -789,5 +793,15 @@ struct volume_options options[] = {
                          "written to the disk",
           .default_value = "on",
         },
+        { .key = {"consistent-metadata"},
+          .type = GF_OPTION_TYPE_BOOL,
+          .default_value = "no",
+          .description = "If this option is enabled, readdirp will force "
+                         "lookups on those entries read whose read child is "
+                         "not the same as that of the parent. This will "
+                         "guarantee that all read operations on a file serve "
+                         "attributes from the same subvol as long as it holds "
+                         " a good copy of the file/dir.",
+        },
         { .key  = {NULL} },
 };