SERVER-36005 Prevent unsafe IndexCatalogEntryImpl::_catalogIsReady call

(cherry picked from commit dfdffb7e4588d41c99e625ade8e9aa638b0c3fd4)

7 files changed, 30 insertions, 4 deletions

diff --git a/src/mongo/db/catalog/collection_catalog_entry.h b/src/mongo/db/catalog/collection_catalog_entry.h
index a55280a6724..f08085d7710 100644
--- a/src/mongo/db/catalog/collection_catalog_entry.h
+++ b/src/mongo/db/catalog/collection_catalog_entry.h
@@ -109,6 +109,8 @@ public:
 
     virtual bool isIndexReady(OperationContext* opCtx, StringData indexName) const = 0;
 
+    virtual bool isIndexPresent(OperationContext* opCtx, StringData indexName) const = 0;
+
     virtual KVPrefix getIndexPrefix(OperationContext* opCtx, StringData indexName) const = 0;
 
     virtual Status removeIndex(OperationContext* opCtx, StringData indexName) = 0;
diff --git a/src/mongo/db/catalog/index_catalog_entry_impl.cpp b/src/mongo/db/catalog/index_catalog_entry_impl.cpp
index f44e5a0f31e..09859e35b4c 100644
--- a/src/mongo/db/catalog/index_catalog_entry_impl.cpp
+++ b/src/mongo/db/catalog/index_catalog_entry_impl.cpp
@@ -167,10 +167,12 @@ bool IndexCatalogEntryImpl::isReady(OperationContext* opCtx) const {
     // minimumSnapshotVersion on a collection.  This means we are unprotected from reading
     // out-of-sync index catalog entries.  To fix this, we uassert if we detect that the
     // in-memory catalog is out-of-sync with the on-disk catalog.
-    if (session && session->inMultiDocumentTransaction() && _catalogIsReady(opCtx) != _isReady) {
-        uasserted(ErrorCodes::SnapshotUnavailable,
-                  str::stream() << "Unable to read from a snapshot due to pending collection"
-                                   " catalog changes; please retry the operation.");
+    if (session && session->inMultiDocumentTransaction()) {
+        if (!_catalogIsPresent(opCtx) || _catalogIsReady(opCtx) != _isReady) {
+            uasserted(ErrorCodes::SnapshotUnavailable,
+                      str::stream() << "Unable to read from a snapshot due to pending collection"
+                                       " catalog changes; please retry the operation.");
+        }
     }
 
     DEV invariant(_isReady == _catalogIsReady(opCtx));
@@ -360,6 +362,10 @@ RecordId IndexCatalogEntryImpl::_catalogHead(OperationContext* opCtx) const {
     return _collection->getIndexHead(opCtx, _descriptor->indexName());
 }
 
+bool IndexCatalogEntryImpl::_catalogIsPresent(OperationContext* opCtx) const {
+    return _collection->isIndexPresent(opCtx, _descriptor->indexName());
+}
+
 bool IndexCatalogEntryImpl::_catalogIsMultikey(OperationContext* opCtx,
                                                MultikeyPaths* multikeyPaths) const {
     return _collection->isIndexMultikey(opCtx, _descriptor->indexName(), multikeyPaths);
diff --git a/src/mongo/db/catalog/index_catalog_entry_impl.h b/src/mongo/db/catalog/index_catalog_entry_impl.h
index 0564c35d7c0..86fa76c6101 100644
--- a/src/mongo/db/catalog/index_catalog_entry_impl.h
+++ b/src/mongo/db/catalog/index_catalog_entry_impl.h
@@ -170,6 +170,7 @@ private:
     class SetHeadChange;
 
     bool _catalogIsReady(OperationContext* opCtx) const;
+    bool _catalogIsPresent(OperationContext* opCtx) const;
     RecordId _catalogHead(OperationContext* opCtx) const;
 
     /**
diff --git a/src/mongo/db/storage/bson_collection_catalog_entry.cpp b/src/mongo/db/storage/bson_collection_catalog_entry.cpp
index 21c1530e00d..a518884be93 100644
--- a/src/mongo/db/storage/bson_collection_catalog_entry.cpp
+++ b/src/mongo/db/storage/bson_collection_catalog_entry.cpp
@@ -190,6 +190,13 @@ RecordId BSONCollectionCatalogEntry::getIndexHead(OperationContext* opCtx,
     return md.indexes[offset].head;
 }
 
+bool BSONCollectionCatalogEntry::isIndexPresent(OperationContext* opCtx,
+                                                StringData indexName) const {
+    MetaData md = _getMetaData(opCtx);
+    int offset = md.findIndexOffset(indexName);
+    return offset >= 0;
+}
+
 bool BSONCollectionCatalogEntry::isIndexReady(OperationContext* opCtx, StringData indexName) const {
     MetaData md = _getMetaData(opCtx);
 
diff --git a/src/mongo/db/storage/bson_collection_catalog_entry.h b/src/mongo/db/storage/bson_collection_catalog_entry.h
index 4401c554775..ea3261350a2 100644
--- a/src/mongo/db/storage/bson_collection_catalog_entry.h
+++ b/src/mongo/db/storage/bson_collection_catalog_entry.h
@@ -72,6 +72,8 @@ public:
 
     virtual bool isIndexReady(OperationContext* opCtx, StringData indexName) const;
 
+    virtual bool isIndexPresent(OperationContext* opCtx, StringData indexName) const;
+
     virtual KVPrefix getIndexPrefix(OperationContext* opCtx, StringData indexName) const;
 
     // ------ for implementors
diff --git a/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.cpp b/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.cpp
index 865d5fff00f..a2a31433a92 100644
--- a/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.cpp
+++ b/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.cpp
@@ -200,6 +200,12 @@ bool NamespaceDetailsCollectionCatalogEntry::isIndexReady(OperationContext* opCt
     return idxNo < getCompletedIndexCount(opCtx);
 }
 
+bool NamespaceDetailsCollectionCatalogEntry::isIndexPresent(OperationContext* opCtx,
+                                                            StringData idxName) const {
+    int idxNo = _findIndexNumber(opCtx, idxName);
+    return idxNo >= 0;
+}
+
 KVPrefix NamespaceDetailsCollectionCatalogEntry::getIndexPrefix(OperationContext* opCtx,
                                                                 StringData indexName) const {
     return KVPrefix::kNotPrefixed;
diff --git a/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.h b/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.h
index 517128ae26d..60cba15378b 100644
--- a/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.h
+++ b/src/mongo/db/storage/mmap_v1/catalog/namespace_details_collection_entry.h
@@ -86,6 +86,8 @@ public:
 
     bool isIndexReady(OperationContext* opCtx, StringData indexName) const final;
 
+    bool isIndexPresent(OperationContext* opCtx, StringData indexName) const final;
+
     KVPrefix getIndexPrefix(OperationContext* opCtx, StringData indexName) const final;
 
     Status removeIndex(OperationContext* opCtx, StringData indexName) final;