SERVER-40436 Ignore the 'flags' field from the 'create' command

29 files changed, 49 insertions, 231 deletions

diff --git a/jstests/auth/lib/commands_lib.js b/jstests/auth/lib/commands_lib.js
index 99b6d9a6924..c7508e61cfc 100644
--- a/jstests/auth/lib/commands_lib.js
+++ b/jstests/auth/lib/commands_lib.js
@@ -2087,7 +2087,7 @@ var authCommandsLib = {
         },
         {
           testname: "collMod",
-          command: {collMod: "foo", usePowerOf2Sizes: true},
+          command: {collMod: "foo"},
           setup: function(db) {
               db.foo.save({});
           },
diff --git a/jstests/auth/user_management_commands_edge_cases.js b/jstests/auth/user_management_commands_edge_cases.js
index 51bf9c950fd..f8447ddd7c8 100644
--- a/jstests/auth/user_management_commands_edge_cases.js
+++ b/jstests/auth/user_management_commands_edge_cases.js
@@ -277,7 +277,6 @@ function runTest(conn) {
 
 jsTest.log('Test standalone');
 var conn = MongoRunner.runMongod({auth: ''});
-conn.getDB('admin').runCommand({setParameter: 1, newCollectionsUsePowerOf2Sizes: false});
 runTest(conn);
 MongoRunner.stopMongod(conn);
 
diff --git a/jstests/auth/user_management_commands_lib.js b/jstests/auth/user_management_commands_lib.js
index 86bf9c13d9e..f05987c2b1d 100644
--- a/jstests/auth/user_management_commands_lib.js
+++ b/jstests/auth/user_management_commands_lib.js
@@ -114,8 +114,7 @@ function runAllUserManagementCommandsTests(conn, writeConcern) {
     (function testGrantRolesToUser() {
         jsTestLog("Testing grantRolesToUser");
 
-        assert.commandFailedWithCode(db.runCommand({collMod: 'foo', usePowerOf2Sizes: true}),
-                                     ErrorCodes.Unauthorized);
+        assert.commandFailedWithCode(db.runCommand({collMod: 'foo'}), ErrorCodes.Unauthorized);
 
         testUserAdmin.grantRolesToUser('spencer',
                                        [
@@ -127,7 +126,7 @@ function runAllUserManagementCommandsTests(conn, writeConcern) {
                                        ],
                                        writeConcern);
 
-        assert.commandWorked(db.runCommand({collMod: 'foo', usePowerOf2Sizes: true}));
+        assert.commandWorked(db.runCommand({collMod: 'foo'}));
         assert.writeOK(db.foo.update({}, {$inc: {a: 1}}));
         assert.eq(3, db.foo.findOne().a);
         assert.eq(1, db.foo.count());
@@ -149,7 +148,7 @@ function runAllUserManagementCommandsTests(conn, writeConcern) {
             ],
             writeConcern);
 
-        assert.commandWorked(db.runCommand({collMod: 'foo', usePowerOf2Sizes: true}));
+        assert.commandWorked(db.runCommand({collMod: 'foo'}));
         hasAuthzError(db.foo.update({}, {$inc: {a: 1}}));
         assert.throws(function() {
             db.foo.findOne();
diff --git a/jstests/core/collmod.js b/jstests/core/collmod.js
index 39db24f8739..6a0081edff6 100644
--- a/jstests/core/collmod.js
+++ b/jstests/core/collmod.js
@@ -1,6 +1,6 @@
 /**
  * Basic js tests for the collMod command.
- * Test setting the usePowerOf2Sizes flag, and modifying TTL indexes.
+ * Test modifying TTL indexes.
  *
  * @tags: [
  *  # Cannot implicitly shard accessed collections because of collection existing when none
@@ -104,36 +104,14 @@ var res =
 debug(res);
 assert.eq(0, res.ok, "shouldn't be able to modify faulty index spec");
 
-// try with new index, this time set both expireAfterSeconds and the usePowerOf2Sizes flag
+// try with new index, this time set expireAfterSeconds
 t.dropIndex({a: 1});
 t.ensureIndex({a: 1}, {"expireAfterSeconds": 50});
-var res = db.runCommand({
-    "collMod": coll,
-    "usePowerOf2Sizes": true,
-    "index": {"keyPattern": {a: 1}, "expireAfterSeconds": 100}
-});
+var res =
+    db.runCommand({"collMod": coll, "index": {"keyPattern": {a: 1}, "expireAfterSeconds": 100}});
 debug(res);
 assert(findTTL({a: 1}, 100), "TTL index should be 100 now");
 
-// Clear usePowerOf2Sizes and enable noPadding. Make sure collection options.flags is updated.
-var res = db.runCommand({"collMod": coll, "usePowerOf2Sizes": false, "noPadding": true});
-debug(res);
-assert.commandWorked(res);
-var info = findCollectionInfo();
-assert.eq(info.options.flags, 2, tojson(info));  // 2 is CollectionOptions::Flag_NoPadding
-
-// Clear noPadding and check results object and options.flags.
-var res = db.runCommand({"collMod": coll, "noPadding": false});
-debug(res);
-assert.commandWorked(res);
-if (!isMongos) {
-    // don't check this for sharding passthrough since mongos has a different output format.
-    assert.eq(res.noPadding_old, true, tojson(res));
-    assert.eq(res.noPadding_new, false, tojson(res));
-}
-var info = findCollectionInfo();
-assert.eq(info.options.flags, 0, tojson(info));
-
 // Tests for collmod over multiple indexes with the same key pattern.
 t.drop();
 assert.commandWorked(db.createCollection(coll));
diff --git a/jstests/core/max_time_ms.js b/jstests/core/max_time_ms.js
index 9633f480d62..8a539cc5493 100644
--- a/jstests/core/max_time_ms.js
+++ b/jstests/core/max_time_ms.js
@@ -417,7 +417,7 @@ assert(res.ok == 1,
        "expected aggregate with maxtime to succeed, ok=" + res.ok + ", code=" + res.code);
 
 // "collMod" command.
-res = t.runCommand("collMod", {usePowerOf2Sizes: true, maxTimeMS: 60 * 1000});
+res = t.runCommand("collMod", {maxTimeMS: 60 * 1000});
 assert(res.ok == 1,
        "expected collmod with maxtime to succeed, ok=" + res.ok + ", code=" + res.code);
 
diff --git a/jstests/libs/override_methods/causally_consistent_index_builds.js b/jstests/libs/override_methods/causally_consistent_index_builds.js
index 613886431c7..ec20a87f588 100644
--- a/jstests/libs/override_methods/causally_consistent_index_builds.js
+++ b/jstests/libs/override_methods/causally_consistent_index_builds.js
@@ -24,9 +24,7 @@
             return res;
         }
 
-        // The 'usePowerOf2Sizes' option is ignored by the server so no actual collection
-        // modification takes place.
-        let collModCmd = {collMod: commandObj[commandName], usePowerOf2Sizes: true};
+        let collModCmd = {collMod: commandObj[commandName]};
         let collModRes = func.apply(conn, makeFuncArgs(collModCmd));
 
         // If a follow-up collMod fails, another command was likely able to execute after the
diff --git a/jstests/noPassthrough/apply_ops_mode.js b/jstests/noPassthrough/apply_ops_mode.js
index a4a6e5a838f..3515f4d8040 100644
--- a/jstests/noPassthrough/apply_ops_mode.js
+++ b/jstests/noPassthrough/apply_ops_mode.js
@@ -85,7 +85,6 @@
         db.adminCommand({applyOps: [collModOp], oplogApplicationMode: "ApplyOps"}));
 
     // Test default succeeds.
-    collModOp.o.usePowerOf2Sizes = true;
     assert.commandWorked(db.adminCommand({
         applyOps: [collModOp],
     }));
diff --git a/jstests/noPassthroughWithMongod/ttl_repl.js b/jstests/noPassthroughWithMongod/ttl_repl.js
index 78ea6c5d6c6..97257da5ce6 100644
--- a/jstests/noPassthroughWithMongod/ttl_repl.js
+++ b/jstests/noPassthroughWithMongod/ttl_repl.js
@@ -25,9 +25,8 @@ var slave1db = slave1.getDB('d');
 var mastercol = masterdb['c'];
 var slave1col = slave1db['c'];
 
-// turn off usePowerOf2Sizes as this tests the flag is set automatically
 mastercol.drop();
-masterdb.createCollection(mastercol.getName(), {usePowerOf2Sizes: false});
+masterdb.createCollection(mastercol.getName());
 
 // create new collection. insert 24 docs, aged at one-hour intervalss
 now = (new Date()).getTime();
diff --git a/jstests/replsets/rollback_all_op_types.js b/jstests/replsets/rollback_all_op_types.js
index 690cff5c4db..7af1a3c654d 100644
--- a/jstests/replsets/rollback_all_op_types.js
+++ b/jstests/replsets/rollback_all_op_types.js
@@ -176,8 +176,6 @@
               op: (db, collName) => {
                   assert.commandWorked(db.runCommand({
                       collMod: collName,
-                      usePowerOf2Sizes: false,
-                      noPadding: true,
                       validator: {a: 1},
                       validationLevel: "moderate",
                       validationAction: "warn"
diff --git a/jstests/sharding/database_and_shard_versioning_all_commands.js b/jstests/sharding/database_and_shard_versioning_all_commands.js
index e3e48cd8ef9..0193cebdb8b 100644
--- a/jstests/sharding/database_and_shard_versioning_all_commands.js
+++ b/jstests/sharding/database_and_shard_versioning_all_commands.js
@@ -73,7 +73,7 @@
                 // Expects the collection to exist, and doesn't implicitly create it.
                 assert.commandWorked(mongosConn.getDB(dbName).runCommand({create: collName}));
             },
-            command: {collMod: collName, noPadding: false},
+            command: {collMod: collName},
             cleanUp: function(mongosConn) {
                 assert(mongosConn.getDB(dbName).getCollection(collName).drop());
             }
diff --git a/jstests/sharding/read_pref_cmd.js b/jstests/sharding/read_pref_cmd.js
index 4a2059276d0..a103338751f 100644
--- a/jstests/sharding/read_pref_cmd.js
+++ b/jstests/sharding/read_pref_cmd.js
@@ -168,7 +168,7 @@ var testReadPreference = function(conn, hostList, isMongos, mode, tagSets, secEx
     // Run a no-op command and wait for it to be applied on secondaries. Due to the asynchronous
     // completion nature of indexes on secondaries, we can guarantee an index build is complete
     // on all secondaries once all secondaries have applied this collMod command.
-    assert.commandWorked(testDB.runCommand({collMod: 'user', usePowerOf2Sizes: true}));
+    assert.commandWorked(testDB.runCommand({collMod: 'user'}));
     assert.commandWorked(testDB.runCommand({getLastError: 1, w: NODE_COUNT}));
 
     // Mongos doesn't implement geoSearch; test it only with ReplicaSetConnection.
diff --git a/jstests/tool/dumprestore_auth.js b/jstests/tool/dumprestore_auth.js
index a4a19650e77..6dbef63ffeb 100644
--- a/jstests/tool/dumprestore_auth.js
+++ b/jstests/tool/dumprestore_auth.js
@@ -60,7 +60,7 @@ assert.eq(0, c.count(), "setup1");
 c.save({a: 22});
 assert.eq(1, c.count(), "setup2");
 
-assert.commandWorked(c.runCommand("collMod", {usePowerOf2Sizes: false}));
+assert.commandWorked(c.runCommand("collMod"));
 
 var collections = c.getDB().getCollectionInfos();
 var fooColl = null;
@@ -70,7 +70,6 @@ collections.forEach(function(coll) {
     }
 });
 assert.neq(null, fooColl, "foo collection doesn't exist");
-assert(!fooColl.options.flags, "find namespaces 1");
 
 t.runTool("dump", "--out", t.ext, "--username", "backup", "--password", "password");
 
@@ -103,7 +102,6 @@ collections.forEach(function(coll) {
     }
 });
 assert.neq(null, fooColl, "foo collection doesn't exist");
-assert(!fooColl.options.flags, "find namespaces 2");
 
 assert.eq(sysUsers, adminDB.system.users.count());
 
@@ -163,7 +161,6 @@ collections.forEach(function(coll) {
     }
 });
 assert.neq(null, fooColl, "foo collection doesn't exist");
-assert(!fooColl.options.flags, "find namespaces 3");
 
 assert.eq(sysUsers, adminDB.system.users.count());
 
diff --git a/src/mongo/db/auth/role_graph_update.cpp b/src/mongo/db/auth/role_graph_update.cpp
index 33820f41233..b5956069f85 100644
--- a/src/mongo/db/auth/role_graph_update.cpp
+++ b/src/mongo/db/auth/role_graph_update.cpp
@@ -327,22 +327,9 @@ Status handleOplogCommand(RoleGraph* roleGraph, const BSONObj& cmdObj) {
         }
     }
 
-    if (cmdName == "collMod") {
+    if (cmdName == "collMod" && cmdObj.nFields() == 1) {
         // We don't care about empty modifications, even if they are on roles collection.
-        if (cmdObj.nFields() == 1) {
-            return Status::OK();
-        }
-
-        // Some arguments are known to be no-ops.
-        auto isNoOpArgument = [](const BSONElement& elem) {
-            return elem.fieldNameStringData() == "usePowerOf2Sizes";
-        };
-
-        // If all arguments are known to be no-ops, we don't care about the operation.
-        auto argument = std::find_if_not(++cmdObj.begin(), cmdObj.end(), isNoOpArgument);
-        if (argument == cmdObj.end()) {
-            return Status::OK();
-        }
+        return Status::OK();
     }
 
     //  No other commands expected.  Warn.
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 1c56a6ae270..bf0c62380c5 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -72,8 +72,6 @@ struct CollModRequest {
     BSONElement collValidator = {};
     std::string collValidationAction = {};
     std::string collValidationLevel = {};
-    BSONElement usePowerOf2Sizes = {};
-    BSONElement noPadding = {};
 };
 
 StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
@@ -230,17 +228,9 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
                 return Status(ErrorCodes::InvalidOptions,
                               str::stream() << "option not supported on a view: " << fieldName);
             }
-            // As of SERVER-17312 we only support these two options. When SERVER-17320 is
-            // resolved this will need to be enhanced to handle other options.
-            typedef CollectionOptions CO;
-
-            if (fieldName == "usePowerOf2Sizes")
-                cmr.usePowerOf2Sizes = e;
-            else if (fieldName == "noPadding")
-                cmr.noPadding = e;
-            else
-                return Status(ErrorCodes::InvalidOptions,
-                              str::stream() << "unknown option to collMod: " << fieldName);
+
+            return Status(ErrorCodes::InvalidOptions,
+                          str::stream() << "unknown option to collMod: " << fieldName);
         }
 
         oplogEntryBuilder->append(e);
@@ -250,47 +240,6 @@ StatusWith<CollModRequest> parseCollModRequest(OperationContext* opCtx,
 }
 
 /**
- * Set a collection option flag for 'UsePowerOf2Sizes' or 'NoPadding'. Appends both the new and
- * old flag setting to the given 'result' builder.
- */
-void setCollectionOptionFlag(OperationContext* opCtx,
-                             Collection* coll,
-                             BSONElement& collOptionElement,
-                             BSONObjBuilder* result) {
-    const StringData flagName = collOptionElement.fieldNameStringData();
-
-    int flag;
-
-    if (flagName == "usePowerOf2Sizes") {
-        flag = CollectionOptions::Flag_UsePowerOf2Sizes;
-    } else if (flagName == "noPadding") {
-        flag = CollectionOptions::Flag_NoPadding;
-    } else {
-        flag = 0;
-    }
-
-    CollectionCatalogEntry* cce = coll->getCatalogEntry();
-
-    const int oldFlags = cce->getCollectionOptions(opCtx).flags;
-    const bool oldSetting = oldFlags & flag;
-    const bool newSetting = collOptionElement.trueValue();
-
-    result->appendBool(flagName.toString() + "_old", oldSetting);
-    result->appendBool(flagName.toString() + "_new", newSetting);
-
-    const int newFlags = newSetting ? (oldFlags | flag)    // set flag
-                                    : (oldFlags & ~flag);  // clear flag
-
-    // NOTE we do this unconditionally to ensure that we note that the user has
-    // explicitly set flags, even if they are just setting the default.
-    cce->updateFlags(opCtx, newFlags);
-
-    const CollectionOptions newOptions = cce->getCollectionOptions(opCtx);
-    invariant(newOptions.flags == newFlags);
-    invariant(newOptions.flagsSet);
-}
-
-/**
  * If uuid is specified, add it to the collection specified by nss. This will error if the
  * collection already has a UUID.
  */
@@ -422,14 +371,6 @@ Status _collModInternal(OperationContext* opCtx,
     if (!cmr.collValidationLevel.empty())
         invariant(coll->setValidationLevel(opCtx, cmr.collValidationLevel));
 
-    // UsePowerof2Sizes
-    if (!cmr.usePowerOf2Sizes.eoo())
-        setCollectionOptionFlag(opCtx, coll, cmr.usePowerOf2Sizes, result);
-
-    // NoPadding
-    if (!cmr.noPadding.eoo())
-        setCollectionOptionFlag(opCtx, coll, cmr.noPadding, result);
-
     // Upgrade unique indexes
     if (upgradeUniqueIndexes) {
         // A cmdObj with an empty collMod, i.e. nFields = 1, implies that it is a Unique Index
diff --git a/src/mongo/db/catalog/collection_catalog_entry.h b/src/mongo/db/catalog/collection_catalog_entry.h
index ae2464f37ba..359e3714dee 100644
--- a/src/mongo/db/catalog/collection_catalog_entry.h
+++ b/src/mongo/db/catalog/collection_catalog_entry.h
@@ -206,12 +206,6 @@ public:
     virtual void updateIndexMetadata(OperationContext* opCtx, const IndexDescriptor* desc) {}
 
     /**
-     * Sets the flags field of CollectionOptions to newValue.
-     * Subsequent calls to getCollectionOptions should have flags==newValue and flagsSet==true.
-     */
-    virtual void updateFlags(OperationContext* opCtx, int newValue) = 0;
-
-    /**
      * Updates the validator for this collection.
      *
      * An empty validator removes all validation.
diff --git a/src/mongo/db/catalog/collection_options.cpp b/src/mongo/db/catalog/collection_options.cpp
index 941c3adf36e..a156754bf14 100644
--- a/src/mongo/db/catalog/collection_options.cpp
+++ b/src/mongo/db/catalog/collection_options.cpp
@@ -172,8 +172,8 @@ Status CollectionOptions::parse(const BSONObj& options, ParseKind kind) {
             else
                 autoIndexId = NO;
         } else if (fieldName == "flags") {
-            flags = e.numberInt();
-            flagsSet = true;
+            // Ignoring this field as it is deprecated.
+            continue;
         } else if (fieldName == "temp") {
             temp = e.trueValue();
         } else if (fieldName == "storageEngine") {
@@ -296,9 +296,6 @@ void CollectionOptions::appendBSON(BSONObjBuilder* builder) const {
     if (autoIndexId != DEFAULT)
         builder->appendBool("autoIndexId", autoIndexId == YES);
 
-    if (flagsSet)
-        builder->append("flags", flags);
-
     if (temp)
         builder->appendBool("temp", true);
 
@@ -371,14 +368,6 @@ bool CollectionOptions::matchesStorageOptions(const CollectionOptions& other,
         return false;
     }
 
-    if (flagsSet != other.flagsSet) {
-        return false;
-    }
-
-    if (flags != other.flags) {
-        return false;
-    }
-
     if (temp != other.temp) {
         return false;
     }
diff --git a/src/mongo/db/catalog/collection_options.h b/src/mongo/db/catalog/collection_options.h
index 753905d3b7d..2558df0f5ea 100644
--- a/src/mongo/db/catalog/collection_options.h
+++ b/src/mongo/db/catalog/collection_options.h
@@ -117,14 +117,6 @@ struct CollectionOptions {
         NO        // do not create _id index
     } autoIndexId = DEFAULT;
 
-    // user flags
-    enum UserFlags {
-        Flag_UsePowerOf2Sizes = 1 << 0,
-        Flag_NoPadding = 1 << 1,
-    };
-    int flags = Flag_UsePowerOf2Sizes;  // a bitvector of UserFlags
-    bool flagsSet = false;
-
     bool temp = false;
 
     // Storage engine collection options. Always owned or empty.
diff --git a/src/mongo/db/catalog/collection_options_test.cpp b/src/mongo/db/catalog/collection_options_test.cpp
index 0fe608c9e16..8065c38f207 100644
--- a/src/mongo/db/catalog/collection_options_test.cpp
+++ b/src/mongo/db/catalog/collection_options_test.cpp
@@ -54,7 +54,6 @@ TEST(CollectionOptions, SimpleRoundTrip) {
     checkRoundTrip(options);
 
     options.setNoIdIndex();
-    options.flags = 5;
     checkRoundTrip(options);
 }
 
diff --git a/src/mongo/db/commands/create.idl b/src/mongo/db/commands/create.idl
index 685b56f483a..576e4521919 100644
--- a/src/mongo/db/commands/create.idl
+++ b/src/mongo/db/commands/create.idl
@@ -113,5 +113,5 @@ commands:
                 optional: true
             flags:
                 description: "DEPRECATED"
-                type: int
+                type: safeInt32
                 optional: true
diff --git a/src/mongo/db/commands/dbcommands.cpp b/src/mongo/db/commands/dbcommands.cpp
index cc993d30dd9..ab42a783d7b 100644
--- a/src/mongo/db/commands/dbcommands.cpp
+++ b/src/mongo/db/commands/dbcommands.cpp
@@ -606,7 +606,7 @@ public:
     }
     std::string help() const override {
         return "Sets collection options.\n"
-               "Example: { collMod: 'foo', usePowerOf2Sizes:true }\n"
+               "Example: { collMod: 'foo', viewOn: 'bar'} "
                "Example: { collMod: 'foo', index: {keyPattern: {a: 1}, expireAfterSeconds: 600} "
                "Example: { collMod: 'foo', index: {name: 'bar', expireAfterSeconds: 600} }\n";
     }
diff --git a/src/mongo/db/op_observer_impl_test.cpp b/src/mongo/db/op_observer_impl_test.cpp
index 979e1f2169e..40adb8c515b 100644
--- a/src/mongo/db/op_observer_impl_test.cpp
+++ b/src/mongo/db/op_observer_impl_test.cpp
@@ -255,8 +255,6 @@ TEST_F(OpObserverTest, CollModWithCollectionOptionsAndTTLInfo) {
     CollectionOptions oldCollOpts;
     oldCollOpts.validationLevel = "strict";
     oldCollOpts.validationAction = "error";
-    oldCollOpts.flags = 2;
-    oldCollOpts.flagsSet = true;
 
     TTLCollModInfo ttlInfo;
     ttlInfo.expireAfterSeconds = Seconds(10);
@@ -288,12 +286,11 @@ TEST_F(OpObserverTest, CollModWithCollectionOptionsAndTTLInfo) {
     // Ensure that the old collection metadata was saved.
     auto o2 = oplogEntry.getObjectField("o2");
     auto o2Expected =
-        BSON("collectionOptions_old" << BSON("flags" << oldCollOpts.flags << "validationLevel"
-                                                     << oldCollOpts.validationLevel
-                                                     << "validationAction"
-                                                     << oldCollOpts.validationAction)
-                                     << "expireAfterSeconds_old"
-                                     << durationCount<Seconds>(ttlInfo.oldExpireAfterSeconds));
+        BSON("collectionOptions_old"
+             << BSON("validationLevel" << oldCollOpts.validationLevel << "validationAction"
+                                       << oldCollOpts.validationAction)
+             << "expireAfterSeconds_old"
+             << durationCount<Seconds>(ttlInfo.oldExpireAfterSeconds));
 
     ASSERT_BSONOBJ_EQ(o2Expected, o2);
 }
diff --git a/src/mongo/db/repl/rollback_test_fixture.cpp b/src/mongo/db/repl/rollback_test_fixture.cpp
index d16e02bf290..e5548d8ad33 100644
--- a/src/mongo/db/repl/rollback_test_fixture.cpp
+++ b/src/mongo/db/repl/rollback_test_fixture.cpp
@@ -276,8 +276,8 @@ void RollbackResyncsCollectionOptionsTest::resyncCollectionOptionsTest(
                                 remoteCollOptionsObj,
                                 BSON("collMod"
                                      << "coll"
-                                     << "noPadding"
-                                     << false),
+                                     << "validationLevel"
+                                     << "strict"),
                                 "coll");
 }
 void RollbackResyncsCollectionOptionsTest::resyncCollectionOptionsTest(
diff --git a/src/mongo/db/repl/rollback_test_fixture.h b/src/mongo/db/repl/rollback_test_fixture.h
index 4424ef7b1fe..8f03742bfd4 100644
--- a/src/mongo/db/repl/rollback_test_fixture.h
+++ b/src/mongo/db/repl/rollback_test_fixture.h
@@ -278,9 +278,9 @@ private:
  * 'remoteCollOptionsObj': the collection options object that the sync source will respond with to
  * the rollback node when it fetches collection metadata.
  *
- * If no command is provided, a collMod operation with a 'noPadding' argument is used to trigger a
- * collection metadata resync, since the rollback of collMod operations does not take into account
- * the actual command object. It simply re-syncs all the collection options.
+ * If no command is provided, a collMod operation with a 'validationLevel' argument is used to
+ * trigger a collection metadata resync, since the rollback of collMod operations does not take into
+ * account the actual command object. It simply re-syncs all the collection options.
  */
 class RollbackResyncsCollectionOptionsTest : public RollbackTest {
 
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index 386a688abbf..014052dcb3b 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -498,8 +498,7 @@ Status rollback_internal::updateFixUpInfoFromLocalOplogEntry(FixUpInfo& fixUpInf
                     }
 
                     if (modification == "validator" || modification == "validationAction" ||
-                        modification == "validationLevel" || modification == "usePowerOf2Sizes" ||
-                        modification == "noPadding") {
+                        modification == "validationLevel") {
                         fixUpInfo.collectionsToResyncMetadata.insert(*uuid);
                         continue;
                     }
@@ -1208,11 +1207,6 @@ void rollback_internal::syncFixUp(OperationContext* opCtx,
             // Set collection to whatever temp status is on the sync source.
             cce->setIsTemp(opCtx, options.temp);
 
-            // Resets collection user flags such as noPadding and usePowerOf2Sizes.
-            if (options.flagsSet || cce->getCollectionOptions(opCtx).flagsSet) {
-                cce->updateFlags(opCtx, options.flags);
-            }
-
             // Set any document validation options. We update the validator fields without
             // parsing/validation, since we fetched the options object directly from the sync
             // source, and we should set our validation options to match it exactly.
diff --git a/src/mongo/db/repl/rs_rollback_test.cpp b/src/mongo/db/repl/rs_rollback_test.cpp
index a9a73e9a54c..2b646b8f3a3 100644
--- a/src/mongo/db/repl/rs_rollback_test.cpp
+++ b/src/mongo/db/repl/rs_rollback_test.cpp
@@ -1779,8 +1779,8 @@ TEST_F(RSRollbackTest, RollbackCollectionModificationCommand) {
 
     BSONObj collModCmd = BSON("collMod"
                               << "t"
-                              << "noPadding"
-                              << false);
+                              << "validationLevel"
+                              << "strict");
     auto collectionModificationOperation =
         makeCommandOp(Timestamp(Seconds(2), 0), coll->uuid().get(), "test.t", collModCmd, 2);
 
@@ -1942,8 +1942,8 @@ TEST_F(RSRollbackTest, RollbackCollectionModificationCommandInvalidCollectionOpt
 
     BSONObj collModCmd = BSON("collMod"
                               << "t"
-                              << "noPadding"
-                              << false);
+                              << "validationLevel"
+                              << "strict");
     auto collectionModificationOperation =
         makeCommandOp(Timestamp(Seconds(2), 0), coll->uuid().get(), "test.t", collModCmd, 2);
 
diff --git a/src/mongo/db/storage/kv/kv_collection_catalog_entry.cpp b/src/mongo/db/storage/kv/kv_collection_catalog_entry.cpp
index 7907e6d068d..20bad4a699d 100644
--- a/src/mongo/db/storage/kv/kv_collection_catalog_entry.cpp
+++ b/src/mongo/db/storage/kv/kv_collection_catalog_entry.cpp
@@ -378,13 +378,6 @@ bool KVCollectionCatalogEntry::isEqualToMetadataUUID(OperationContext* opCtx,
     return md.options.uuid && md.options.uuid == uuid;
 }
 
-void KVCollectionCatalogEntry::updateFlags(OperationContext* opCtx, int newValue) {
-    MetaData md = _getMetaData(opCtx);
-    md.options.flags = newValue;
-    md.options.flagsSet = true;
-    _catalog->putMetaData(opCtx, ns().toString(), md);
-}
-
 void KVCollectionCatalogEntry::updateValidator(OperationContext* opCtx,
                                                const BSONObj& validator,
                                                StringData validationLevel,
diff --git a/src/mongo/db/storage/kv/kv_collection_catalog_entry.h b/src/mongo/db/storage/kv/kv_collection_catalog_entry.h
index 01b4dbe0ffe..bddbd19399a 100644
--- a/src/mongo/db/storage/kv/kv_collection_catalog_entry.h
+++ b/src/mongo/db/storage/kv/kv_collection_catalog_entry.h
@@ -98,8 +98,6 @@ public:
                           StringData idxName,
                           long long newExpireSeconds) final;
 
-    void updateFlags(OperationContext* opCtx, int newValue) final;
-
     void updateIndexMetadata(OperationContext* opCtx, const IndexDescriptor* desc) final;
 
     void updateValidator(OperationContext* opCtx,
diff --git a/src/mongo/shell/db.js b/src/mongo/shell/db.js
index 29c7c549e88..d12e872e417 100644
--- a/src/mongo/shell/db.js
+++ b/src/mongo/shell/db.js
@@ -297,7 +297,6 @@ var DB;
             capped: if true, this is a capped collection (where old data rolls out).
         </li>
         <li> max: maximum number of objects if capped (optional).</li>
-        <li> usePowerOf2Sizes: if true, set usePowerOf2Sizes allocation for the collection.</li>
         <li>
             storageEngine: BSON document containing storage engine specific options. Format:
                            {
@@ -319,42 +318,11 @@ var DB;
 
      * @param {String} name Name of new collection to create
      * @param {Object} options Object with options for call.  Options are listed above.
-     * @return SOMETHING_FIXME
+     * @return {Object} returned has member ok set to true if operation succeeds, false otherwise.
     */
     DB.prototype.createCollection = function(name, opt) {
         var options = opt || {};
 
-        // We have special handling for the 'flags' field, and provide sugar for specific flags. If
-        // the user specifies any flags we send the field in the command. Otherwise, we leave it
-        // blank and use the server's defaults.
-        var sendFlags = false;
-        var flags = 0;
-        if (options.usePowerOf2Sizes != undefined) {
-            print(
-                "WARNING: The 'usePowerOf2Sizes' flag is ignored in 3.0 and higher as all MMAPv1 " +
-                "collections use fixed allocation sizes unless the 'noPadding' flag is specified");
-
-            sendFlags = true;
-            if (options.usePowerOf2Sizes) {
-                flags |= 1;  // Flag_UsePowerOf2Sizes
-            }
-            delete options.usePowerOf2Sizes;
-        }
-        if (options.noPadding != undefined) {
-            sendFlags = true;
-            if (options.noPadding) {
-                flags |= 2;  // Flag_NoPadding
-            }
-            delete options.noPadding;
-        }
-
-        // New flags must be added above here.
-        if (sendFlags) {
-            if (options.flags != undefined)
-                throw Error("Can't set 'flags' with either 'usePowerOf2Sizes' or 'noPadding'");
-            options.flags = flags;
-        }
-
         var cmd = {create: name};
         Object.extend(cmd, options);
 
diff --git a/src/mongo/shell/replsettest.js b/src/mongo/shell/replsettest.js
index 76a6100de51..d45499ead90 100644
--- a/src/mongo/shell/replsettest.js
+++ b/src/mongo/shell/replsettest.js
@@ -1494,8 +1494,7 @@ var ReplSetTest = function(opts) {
         // Run a no-op command and wait for it to be applied on secondaries. Due to the asynchronous
         // completion nature of indexes on secondaries, we can guarantee an index build is complete
         // on all secondaries once all secondaries have applied this collMod command.
-        assert.commandWorked(this.getPrimary().getDB(dbName).runCommand(
-            {collMod: collName, usePowerOf2Sizes: true}));
+        assert.commandWorked(this.getPrimary().getDB(dbName).runCommand({collMod: collName}));
         this.awaitReplication();
     };
 
@@ -1699,16 +1698,11 @@ var ReplSetTest = function(opts) {
                     // filter to take advantage of the fact that a simple 'collection' filter will
                     // skip view evaluation, and therefore won't fail on an invalid view.
                     if (!collInfo.name.startsWith('system.')) {
-                        // 'usePowerOf2Sizes' is ignored by the server so no actual collection
-                        // modification takes place. We intentionally await replication without
-                        // doing any I/O to avoid any overhead from allocating or deleting data
-                        // files when using the MMAPv1 storage engine. We call awaitReplication()
-                        // later on to ensure the collMod is replicated to all nodes.
+                        // We intentionally await replication without doing any I/O to avoid any
+                        // overhead. We call awaitReplication() later on to ensure the collMod
+                        // is replicated to all nodes.
                         try {
-                            assert.commandWorked(dbHandle.runCommand({
-                                collMod: collInfo.name,
-                                usePowerOf2Sizes: true,
-                            }));
+                            assert.commandWorked(dbHandle.runCommand({collMod: collInfo.name}));
                         } catch (e) {
                             // Ignore NamespaceNotFound errors because a background thread could
                             // have dropped the collection after getCollectionInfos but before
@@ -1954,6 +1948,11 @@ var ReplSetTest = function(opts) {
                                     primaryInfo.info.uuid = null;
                                     secondaryInfo.info.uuid = null;
                                 }
+
+                                // Ignore the 'flags' collection option as it was removed in 4.2
+                                primaryInfo.options.flags = null;
+                                secondaryInfo.options.flags = null;
+
                                 if (!bsonBinaryEqual(secondaryInfo, primaryInfo)) {
                                     print(msgPrefix +
                                           ', the primary and secondary have different ' +