cluster/ec: Handle lookup failures while op in progress

Change-Id: Ia1834ec23d5de615526d4d4e4d2e32aff155b7f7
BUG: 1211962
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/10806
Tested-by: NetBSD Build System
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>

2 files changed, 23 insertions, 12 deletions

diff --git a/xlators/cluster/ec/src/ec-common.c b/xlators/cluster/ec/src/ec-common.c
index 393d9142797..afd46c095f3 100644
--- a/xlators/cluster/ec/src/ec-common.c
+++ b/xlators/cluster/ec/src/ec-common.c
@@ -1206,14 +1206,16 @@ void ec_get_size_version(ec_fop_data_t * fop)
 	    loc.path = NULL;
 	    loc.name = NULL;
         }
-	/* For normal fops, ec_lookup() must succeed on at least EC_MINIMUM_MIN
-	 * bricks, however when this is called as part of a self-heal operation
-	 * the mask of target bricks (fop->mask) could contain less than
-	 * EC_MINIMUM_MIN bricks, causing the lookup to always fail. Thus we
-	 * always use the same minimum used for the main fop.
+        /* For normal fops, ec_[f]xattrop() must succeed on at least
+         * EC_MINIMUM_MIN bricks, however when this is called as part of
+         * a self-heal operation the mask of target bricks (fop->mask) could
+         * contain less than EC_MINIMUM_MIN bricks, causing the lookup to
+         * always fail. Thus we always use the same minimum used for the main
+         * fop.
 	 */
-	 ec_lookup(fop->frame, fop->xl, fop->mask, fop->minimum,
-                      ec_get_size_version_set, NULL, &loc, xdata);
+        ec_xattrop (fop->frame, fop->xl, fop->mask, fop->minimum,
+                    ec_prepare_update_cbk, NULL, &loc,
+                    GF_XATTROP_ADD_ARRAY64, xdata, NULL);
     } else {
         if (ec_loc_from_fd(fop->xl, &loc, fop->fd) != 0) {
 	    goto out;
diff --git a/xlators/cluster/ec/src/ec-generic.c b/xlators/cluster/ec/src/ec-generic.c
index d957bf6533d..9d64735df55 100644
--- a/xlators/cluster/ec/src/ec-generic.c
+++ b/xlators/cluster/ec/src/ec-generic.c
@@ -964,9 +964,20 @@ int32_t ec_manager_lookup(ec_fop_data_t * fop, int32_t state)
             return EC_STATE_PREPARE_ANSWER;
 
         case EC_STATE_PREPARE_ANSWER:
+            /*
+             * Lookup happens without any lock, so there is a chance that it
+             * will have answers before modification happened and after
+             * modification happened in the same response. So choose the next
+             * best answer when the answers don't match for EC_MINIMUM_MIN
+             */
+
+            if (!fop->answer && !list_empty(&fop->cbk_list)) {
+                fop->answer = list_entry (fop->cbk_list.next, ec_cbk_data_t,
+                                          list);
+            }
+
             cbk = fop->answer;
-            if (cbk != NULL)
-            {
+            if (cbk != NULL) {
                 if (!ec_dict_combine(cbk, EC_COMBINE_XDATA))
                 {
                     if (cbk->op_ret >= 0)
@@ -986,9 +997,7 @@ int32_t ec_manager_lookup(ec_fop_data_t * fop, int32_t state)
 
                     ec_lookup_rebuild(fop->xl->private, fop, cbk);
                 }
-            }
-            else
-            {
+            } else {
                 ec_fop_set_error(fop, EIO);
             }