cluster/distribute: handle dht_layout_normalize errors differently in

dht_lookup_dir_cbk and dht_discover_complete.

return value from dht_layout_normalize is interpreted as follows:

ret > 0 - number of subvolumes returned ENOENT errors.
ret = 0 - no anomalies found.
ret < 0 - there are holes/overlaps.

We need to handle errors differently in dht_discover_cbk because,
if a subvolume is newly added, the directory will not be present on it
and we cannot create a directory there since a nameless lookup has
resulted execution in this code-path. Hence if directory is guaranteed
to be present in atleast one subvolume and there are no holes/overlaps
in the layout, lookup can be treated as successful.

there is no change in behaviour dht_lookup_dir_cbk caused by this
patch.

Change-Id: I9b0b510f1c7de187be95a47da6c9ec57b5e38d1d
BUG: 802233
Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Reviewed-on: http://review.gluster.com/3069
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

2 files changed, 22 insertions, 15 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index 4010004f610..500c9735fc1 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -190,11 +190,15 @@ dht_discover_complete (xlator_t *this, call_frame_t *discover_frame)
                 }
         } else {
                 ret = dht_layout_normalize (this, &local->loc, layout);
-
-                if (ret != 0) {
+                if ((ret < 0) || ((ret > 0) && (local->op_ret != 0))) {
+                        /* either the layout is incorrect or the directory is
+                         * not found even in one subvolume.
+                         */
                         gf_log (this->name, GF_LOG_DEBUG,
-                                "normalizing failed on %s",
-                                local->loc.path);
+                                "normalizing failed on %s "
+                                "(overlaps/holes present: %s, "
+                                "ENOENT errors: %d)", local->loc.path,
+                                (ret < 0) ? "yes" : "no", (ret > 0) ? ret : 0);
                         op_errno = EINVAL;
                         goto out;
                 }
diff --git a/xlators/cluster/dht/src/dht-layout.c b/xlators/cluster/dht/src/dht-layout.c
index d89e154214e..d1f8c9fbb0d 100644
--- a/xlators/cluster/dht/src/dht-layout.c
+++ b/xlators/cluster/dht/src/dht-layout.c
@@ -571,7 +571,6 @@ dht_layout_normalize (xlator_t *this, loc_t *loc, dht_layout_t *layout)
         uint32_t     down = 0;
         uint32_t     misc = 0;
 
-
         ret = dht_layout_sort (layout);
         if (ret == -1) {
                 gf_log (this->name, GF_LOG_WARNING,
@@ -599,24 +598,28 @@ dht_layout_normalize (xlator_t *this, loc_t *loc, dht_layout_t *layout)
                                 "found anomalies in %s. holes=%d overlaps=%d",
                                 loc->path, holes, overlaps);
                 }
-                ret = 1;
+                ret = -1;
         }
 
         for (i = 0; i < layout->cnt; i++) {
-                /* TODO During DHT selfheal rewrite (almost) find a better place to
-                 * detect this - probably in dht_layout_anomalies()
+                /* TODO During DHT selfheal rewrite (almost) find a better place
+                 * to detect this - probably in dht_layout_anomalies()
                  */
                 if (layout->list[i].err > 0) {
-                        gf_log (this->name, GF_LOG_DEBUG,
-                                "path=%s err=%s on subvol=%s",
-                                loc->path, strerror (layout->list[i].err),
-                                (layout->list[i].xlator ?
-                                 layout->list[i].xlator->name : "<>"));
-                        if (layout->list[i].err == ENOENT)
-                                ret = 1;
+                        gf_log_callingfn (this->name, GF_LOG_DEBUG,
+                                          "path=%s err=%s on subvol=%s",
+                                          loc->path,
+                                          strerror (layout->list[i].err),
+                                          (layout->list[i].xlator ?
+                                           layout->list[i].xlator->name
+                                           : "<>"));
+                        if ((layout->list[i].err == ENOENT) && (ret >= 0)) {
+                                ret++;
+                        }
                 }
         }
 
+
 out:
         return ret;
 }