server: Stat collector solidfire capacity fix (#4918)

Fixes regression introduced in 71c5dbc
which would cause capacity bytes of certain pools to be update which
shouldn't get updated by StatsCollector such as solidfire.

Fixes #4911

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

Author: yadvr

server/src/main/java/com/cloud/server/StatsCollector.java

@@ -1020,14 +1020,22 @@ protected void runInContext() {
                         if (answer != null && answer.getResult()) {
                             storagePoolStats.put(pool.getId(), (StorageStats)answer);
 
+                            boolean poolNeedsUpdating = false;
                             // Seems like we have dynamically updated the pool size since the prev. size and the current do not match
-                            if (pool.getCapacityBytes() != ((StorageStats)answer).getCapacityBytes() ||
-                                    pool.getUsedBytes() != ((StorageStats)answer).getByteUsed()) {
-                                pool.setCapacityBytes(((StorageStats)answer).getCapacityBytes());
-                                if (pool.getStorageProviderName().equalsIgnoreCase(DataStoreProvider.DEFAULT_PRIMARY)) {
-                                    pool.setUsedBytes(((StorageStats) answer).getByteUsed());
-                                    pool.setUpdateTime(new Date());
+                            if (_storagePoolStats.get(poolId) != null && _storagePoolStats.get(poolId).getCapacityBytes() != ((StorageStats)answer).getCapacityBytes()) {
+                                if (((StorageStats)answer).getCapacityBytes() > 0) {
+                                    pool.setCapacityBytes(((StorageStats)answer).getCapacityBytes());
+                                    poolNeedsUpdating = true;
+                                } else {
+                                    s_logger.warn("Not setting capacity bytes, received " + ((StorageStats)answer).getCapacityBytes()  + " capacity for pool ID " + poolId);
                                 }
+                            }
+                            if (pool.getUsedBytes() != ((StorageStats)answer).getByteUsed() && pool.getStorageProviderName().equalsIgnoreCase(DataStoreProvider.DEFAULT_PRIMARY)) {
+                                pool.setUsedBytes(((StorageStats) answer).getByteUsed());
+                                poolNeedsUpdating = true;
+                            }
+                            if (poolNeedsUpdating) {
+                                pool.setUpdateTime(new Date());
                                 _storagePoolDao.update(pool.getId(), pool);
                             }
                         }