afr: thin-arbiter read txn changes

If both data bricks are up, read subvol will be based on read_subvols.

If only one data brick is up:
- First qeury the data-brick that is up. If it blames the other brick,
allow the reads.

- If if doesn't, query the TA to obtain the source of truth.

TODO: See if in-memory state can be maintained for read txns (BZ 1624358).

updates: bz#1579788
Change-Id: I61eec35592af3a1aaf9f90846d9a358b2e4b2fcc
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 702973a6ef4..641485b1ed0 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -1310,6 +1310,14 @@ afr_inode_refresh_done (call_frame_t *frame, xlator_t *this, int error)
                 goto refresh_done;
         }
 
+        if (priv->thin_arbiter_count && local->is_read_txn &&
+            AFR_COUNT (success_replies, priv->child_count) !=
+                       priv->child_count) {
+                /* We need to query the good bricks and/or thin-arbiter.*/
+                error = EINVAL;
+                goto refresh_done;
+        }
+
 	ret = afr_replies_interpret (frame, this, local->refreshinode,
                                      &start_heal);
 
@@ -6977,3 +6985,17 @@ afr_ta_post_op_unlock (xlator_t *this, loc_t *loc)
 out:
         return ret;
 }
+
+call_frame_t *
+afr_ta_frame_create (xlator_t *this)
+{
+        call_frame_t *frame    = NULL;
+        void         *lk_owner = NULL;
+
+        frame = create_frame (this, this->ctx->pool);
+        if (!frame)
+                return NULL;
+        lk_owner = (void *)this;
+        afr_set_lk_owner (frame, this, lk_owner);
+        return frame;
+}