afr: let eager-locking do its own overlap checks

Today there is a non-obvious dependence of eager-locking on
write-behind. The reason is that eager-locking works as long
as the inheriting transaction has no overlaps with any of the
transactions already in progress. While write-behind provides
non-overlapping writes as a side-effect most of times (and only
guarantees it when strict-write-ordering option is enabled,
which is not on by default) eager-lock needs the behavior
as a guarantee. This is leading to complex and unwanted checks
for the presence of write-behind in the graph, for the simple
task of checking for overlaps.

This patch removes the interdependence between eager-locking
and write-behind by making eager-locking do its own overlap checks
with in-progress writes.

Change-Id: Iccba1185aeb5f1e7f060089c895a62840787133f
BUG: 912581
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/4782
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 89d964056a0..a9acb409490 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -2520,6 +2520,8 @@ __afr_fd_ctx_set (xlator_t *this, fd_t *fd)
         INIT_LIST_HEAD (&fd_ctx->entries);
         fd_ctx->call_child = -1;
 
+        INIT_LIST_HEAD (&fd_ctx->eager_locked);
+
         ret = __fd_ctx_set (fd, this, (uint64_t)(long) fd_ctx);
         if (ret)
                 gf_log (this->name, GF_LOG_DEBUG,
@@ -4086,8 +4088,9 @@ afr_transaction_local_init (afr_local_t *local, xlator_t *this)
                                                            AFR_NUM_CHANGE_LOGS);
         if (!local->transaction.txn_changelog)
                 goto out;
-        if (local->fd && (local->transaction.type == AFR_DATA_TRANSACTION))
-                local->transaction.eager_lock_on = priv->eager_lock;
+
+	INIT_LIST_HEAD (&local->transaction.eager_locked);
+
         ret = 0;
 out:
         return ret;