cluster/distribute: Ignore non-participating subvols for layout checks

Backporting fix http://review.gluster.org/#/c/4668/

When subvols-per-directory is < available subvols, then there are layouts
which are not populated. This leads to incorrect identification of holes or
overlaps. We need to ignore layouts, which have err == 0, and start == stop.
In the current scenario (start == stop == 0).

Additionally, in layout-merge, treat missing xattrs as err = 0. In case of
missing layouts, anomalies will reset them.

For any other valid subvoles, err != 0 in case of layouts being zeroed out.

Also reverted back dht_selfheal_dir_xattr, which does layout calculation only
on subvols which have errors.

BUG: 921408
Change-Id: I75a8edcb92af5b53b3253c9addd7a812e9242836
Signed-off-by: shishir gowda <sgowda@redhat.com>
Reviewed-on: http://review.gluster.org/4800
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 23 insertions, 17 deletions

diff --git a/xlators/cluster/dht/src/dht-layout.c b/xlators/cluster/dht/src/dht-layout.c
index 34a7475bdc3..3331db5c518 100644
--- a/xlators/cluster/dht/src/dht-layout.c
+++ b/xlators/cluster/dht/src/dht-layout.c
@@ -365,7 +365,7 @@ dht_layout_merge (xlator_t *this, dht_layout_t *layout, xlator_t *subvol,
         }
 
         if (ret != 0) {
-                layout->list[i].err = -1;
+                layout->list[i].err = 0;
                 gf_log (this->name, GF_LOG_TRACE,
                         "missing disk layout on %s. err = %d",
                         subvol->name, err);
@@ -529,23 +529,29 @@ dht_layout_anomalies (xlator_t *this, loc_t *loc, dht_layout_t *layout,
         prev_stop = last_stop;
 
         for (i = 0; i < layout->cnt; i++) {
-                if (layout->list[i].err) {
-                        switch (layout->list[i].err) {
-                        case -1:
-                        case ENOENT:
-                                missing++;
-                                break;
-                        case ENOTCONN:
-                                down++;
-                                break;
-                        case ENOSPC:
-                                no_space++;
-                                break;
-                        default:
-                                misc++;
+                switch (layout->list[i].err) {
+                case -1:
+                case ENOENT:
+                        missing++;
+                        break;
+                case ENOTCONN:
+                        down++;
+                        break;
+                case ENOSPC:
+                        no_space++;
+                        break;
+                case 0:
+                        /* if err == 0 and start == stop, then it is a non misc++;
+                         * participating subvolume(spread-cnt). Then, do not
+                         * check for anomalies. If start != stop, then treat it
+                         * as misc err */
+                        if (layout->list[i].start == layout->list[i].stop) {
+                                continue;
                         }
-                        continue;
-                }
+                        break;
+                default:
+                        misc++;
+                 }
 
                 is_virgin = 0;