Merge pull request ceph#15657 from xiexingguo/wip-reshard-allocation

os/bluestore: fix potential access violation

Reviewed-by: Igor Fedotov <[email protected]>

src/os/bluestore/BlueStore.cc

@@ -2181,16 +2181,21 @@ void BlueStore::ExtentMap::reshard(
       new_shard_info.begin(),
       new_shard_info.end());
     shards.insert(shards.begin() + si_begin, new_shard_info.size(), Shard());
-    unsigned n = sv.size();
     si_end = si_begin + new_shard_info.size();
-    for (unsigned i = si_begin; i < si_end; ++i) {
+
+    assert(sv.size() == shards.size());
+
+    // note that we need to update every shard_info of shards here,
+    // as sv might have been totally re-allocated above
+    for (unsigned i = 0; i < shards.size(); i++) {
       shards[i].shard_info = &sv[i];
+    }
+
+    // mark newly added shards as dirty
+    for (unsigned i = si_begin; i < si_end; ++i) {
       shards[i].loaded = true;
       shards[i].dirty = true;
     }
-    for (unsigned i = si_end; i < n; ++i) {
-      shards[i].shard_info = &sv[i];
-    }
   }
   dout(20) << __func__ << "  fin " << sv << dendl;
   inline_bl.clear();