cluster/dht: Prevent dht_access from going into a loop.

If access fails with ENOTCONN, do not wind to same subvol.
We wind to first-up-subvol if access fails with ENOTCONN.
In few cases, if dht has only 1 subvolume, and access fails with
ENOTCONN, we go into a infinite loop of winding to same subvol

The fix is to check if we previously wound to same subvol, and
fail if first-up-subvol is same.

Change-Id: Ib5d3ce7d33e8ea09147905a7df1ed280874fa549
BUG: 983431
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.org/5319
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/xlators/cluster/dht/src/dht-inode-read.c b/xlators/cluster/dht/src/dht-inode-read.c
index d9b311fe219..10f59ab26a1 100644
--- a/xlators/cluster/dht/src/dht-inode-read.c
+++ b/xlators/cluster/dht/src/dht-inode-read.c
@@ -501,18 +501,27 @@ dht_access_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
         int          ret = -1;
         dht_local_t *local = NULL;
         xlator_t    *subvol = NULL;
+        call_frame_t *prev = NULL;
 
         local = frame->local;
+        prev = cookie;
 
+        if (!prev || !prev->this)
+                goto out;
         if (local->call_cnt != 1)
                 goto out;
         if ((op_ret == -1) && (op_errno == ENOTCONN) &&
             IA_ISDIR(local->loc.inode->ia_type)) {
 
-                subvol = dht_first_up_subvol (this);
+                subvol = dht_subvol_next_available (this, prev->this);
                 if (!subvol)
                         goto out;
 
+                /* check if we are done with visiting every node */
+                if (subvol == local->cached_subvol) {
+                        goto out;
+                }
+
                 STACK_WIND (frame, dht_access_cbk, subvol, subvol->fops->access,
                             &local->loc, local->rebalance.flags, NULL);
                 return 0;