Merge #11687: External wallet files

be8ab7d08 Create new wallet databases as directories rather than files (Russell Yanofsky)
26c06f24e Allow wallet files not in -walletdir directory (Russell Yanofsky)
d8a99f65e Allow wallet files in multiple directories (Russell Yanofsky)

Pull request description:

  This change consists of three commits:

  * The first commit is a pure refactoring that removes the restriction that two wallets can only be opened at the same time if they are contained in the same directory.
  * The second commit removes the restriction that `-wallet` filenames can only refer to files in the `-walletdir` directory.
  * The third commit makes second commit a little safer by changing bitcoin to create wallet databases as directories rather than files, so they can be safely backed up.

  All three commits should be straightforward:

  *  The first commit adds around 20 lines of new code and then updates a bunch of function signatures (generally updating them to take plain fs::path parameters, instead of combinations of strings, fs::paths, and objects like CDBEnv and CWalletDBWrapper).
  * The second commit removes two `-wallet` filename checks and adds some test cases to the multiwallet unit test.
  * The third commit just changes the mapping from specified wallet paths to bdb environment & data paths.

    ---

  **Note:** For anybody looking at this PR for the first time, I think you can skip the comments before _20 Nov_ and start reading at https://github.com/bitcoin/bitcoin/pull/11687#issuecomment-345625565. Comments before  _20 Nov_ were about an earlier version of the PR that didn't include the third commit, and then confusion from not seeing the first commit.

Tree-SHA512: 00bbb120fe0df847cf57014f75f1f7f1f58b0b62fa0b3adab4560163ebdfe06ccdfff33b4231693f03c5dc23601cb41954a07bcea9a4919c8d42f7d62bcf6024

17 files changed, 313 insertions, 207 deletions

diff --git a/doc/release-notes.md b/doc/release-notes.md
index ac49dc7909..8fcd2a9163 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -63,6 +63,36 @@ RPC changes
 
 - The `fundrawtransaction` rpc will reject the previously deprecated `reserveChangeKey` option.
 
+External wallet files
+---------------------
+
+The `-wallet=<path>` option now accepts full paths instead of requiring wallets
+to be located in the -walletdir directory.
+
+Newly created wallet format
+---------------------------
+
+If `-wallet=<path>` is specified with a path that does not exist, it will now
+create a wallet directory at the specified location (containing a wallet.dat
+data file, a db.log file, and database/log.?????????? files) instead of just
+creating a data file at the path and storing log files in the parent
+directory. This should make backing up wallets more straightforward than
+before because the specified wallet path can just be directly archived without
+having to look in the parent directory for transaction log files.
+
+For backwards compatibility, wallet paths that are names of existing data files
+in the `-walletdir` directory will continue to be accepted and interpreted the
+same as before.
+
+Low-level RPC changes
+---------------------
+
+- When bitcoin is not started with any `-wallet=<path>` options, the name of
+  the default wallet returned by `getwalletinfo` and `listwallets` RPCs is
+  now the empty string `""` instead of `"wallet.dat"`. If bitcoin is started
+  with any `-wallet=<path>` options, there is no change in behavior, and the
+  name of any wallet is just its `<path>` string.
+
 Credits
 =======
 
diff --git a/src/bench/coin_selection.cpp b/src/bench/coin_selection.cpp
index 6f438b60e9..98965840c7 100644
--- a/src/bench/coin_selection.cpp
+++ b/src/bench/coin_selection.cpp
@@ -32,7 +32,7 @@ static void addCoin(const CAmount& nValue, const CWallet& wallet, std::vector<CO
 // (https://github.com/bitcoin/bitcoin/issues/7883#issuecomment-224807484)
 static void CoinSelection(benchmark::State& state)
 {
-    const CWallet wallet;
+    const CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
     std::vector<COutput> vCoins;
     LOCK(wallet.cs_wallet);
 
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index a60d3b3b6d..41f1e5786c 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -46,7 +46,7 @@ std::string HelpMessageCli()
     strUsage += HelpMessageOpt("-rpcport=<port>", strprintf(_("Connect to JSON-RPC on <port> (default: %u or testnet: %u)"), defaultBaseParams->RPCPort(), testnetBaseParams->RPCPort()));
     strUsage += HelpMessageOpt("-rpcuser=<user>", _("Username for JSON-RPC connections"));
     strUsage += HelpMessageOpt("-rpcwait", _("Wait for RPC server to start"));
-    strUsage += HelpMessageOpt("-rpcwallet=<walletname>", _("Send RPC for non-default wallet on RPC server (argument is wallet filename in bitcoind directory, required if bitcoind/-Qt runs with multiple wallets)"));
+    strUsage += HelpMessageOpt("-rpcwallet=<walletname>", _("Send RPC for non-default wallet on RPC server (needs to exactly match corresponding -wallet option passed to bitcoind)"));
     strUsage += HelpMessageOpt("-stdin", _("Read extra arguments from standard input, one per line until EOF/Ctrl-D (recommended for sensitive information such as passphrases).  When combined with -stdinrpcpass, the first line from standard input is used for the RPC password."));
     strUsage += HelpMessageOpt("-stdinrpcpass", strprintf(_("Read RPC password from standard input as a single line.  When combined with -stdin, the first line from standard input is used for the RPC password.")));
 
@@ -339,8 +339,8 @@ static UniValue CallRPC(BaseRequestHandler *rh, const std::string& strMethod, co
 
     // check if we should use a special wallet endpoint
     std::string endpoint = "/";
-    std::string walletName = gArgs.GetArg("-rpcwallet", "");
-    if (!walletName.empty()) {
+    if (!gArgs.GetArgs("-rpcwallet").empty()) {
+        std::string walletName = gArgs.GetArg("-rpcwallet", "");
         char *encodedURI = evhttp_uriencode(walletName.c_str(), walletName.size(), false);
         if (encodedURI) {
             endpoint = "/wallet/"+ std::string(encodedURI);
diff --git a/src/qt/test/wallettests.cpp b/src/qt/test/wallettests.cpp
index 5ba75cc91d..976aadc0af 100644
--- a/src/qt/test/wallettests.cpp
+++ b/src/qt/test/wallettests.cpp
@@ -158,9 +158,7 @@ void TestGUI()
     for (int i = 0; i < 5; ++i) {
         test.CreateAndProcessBlock({}, GetScriptForRawPubKey(test.coinbaseKey.GetPubKey()));
     }
-    bitdb.MakeMock();
-    std::unique_ptr<CWalletDBWrapper> dbw(new CWalletDBWrapper(&bitdb, "wallet_test.dat"));
-    CWallet wallet(std::move(dbw));
+    CWallet wallet("mock", CWalletDBWrapper::CreateMock());
     bool firstRun;
     wallet.LoadWallet(firstRun);
     {
@@ -261,9 +259,6 @@ void TestGUI()
     QPushButton* removeRequestButton = receiveCoinsDialog.findChild<QPushButton*>("removeRequestButton");
     removeRequestButton->click();
     QCOMPARE(requestTableModel->rowCount({}), currentRowCount-1);
-
-    bitdb.Flush(true);
-    bitdb.Reset();
 }
 
 }
diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 23c6279128..ebe7b48da0 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -52,20 +52,55 @@ void CheckUniqueFileid(const CDBEnv& env, const std::string& filename, Db& db)
         }
     }
 }
+
+CCriticalSection cs_db;
+std::map<std::string, CDBEnv> g_dbenvs; //!< Map from directory name to open db environment.
 } // namespace
 
+CDBEnv* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename)
+{
+    fs::path env_directory;
+    if (fs::is_regular_file(wallet_path)) {
+        // Special case for backwards compatibility: if wallet path points to an
+        // existing file, treat it as the path to a BDB data file in a parent
+        // directory that also contains BDB log files.
+        env_directory = wallet_path.parent_path();
+        database_filename = wallet_path.filename().string();
+    } else {
+        // Normal case: Interpret wallet path as a directory path containing
+        // data and log files.
+        env_directory = wallet_path;
+        database_filename = "wallet.dat";
+    }
+    LOCK(cs_db);
+    // Note: An ununsed temporary CDBEnv object may be created inside the
+    // emplace function if the key already exists. This is a little inefficient,
+    // but not a big concern since the map will be changed in the future to hold
+    // pointers instead of objects, anyway.
+    return &g_dbenvs.emplace(std::piecewise_construct, std::forward_as_tuple(env_directory.string()), std::forward_as_tuple(env_directory)).first->second;
+}
+
 //
 // CDB
 //
 
-CDBEnv bitdb;
-
-void CDBEnv::EnvShutdown()
+void CDBEnv::Close()
 {
     if (!fDbEnvInit)
         return;
 
     fDbEnvInit = false;
+
+    for (auto& db : mapDb) {
+        auto count = mapFileUseCount.find(db.first);
+        assert(count == mapFileUseCount.end() || count->second == 0);
+        if (db.second) {
+            db.second->close(0);
+            delete db.second;
+            db.second = nullptr;
+        }
+    }
+
     int ret = dbenv->close(0);
     if (ret != 0)
         LogPrintf("CDBEnv::EnvShutdown: Error %d shutting down database environment: %s\n", ret, DbEnv::strerror(ret));
@@ -80,29 +115,25 @@ void CDBEnv::Reset()
     fMockDb = false;
 }
 
-CDBEnv::CDBEnv()
+CDBEnv::CDBEnv(const fs::path& dir_path) : strPath(dir_path.string())
 {
     Reset();
 }
 
 CDBEnv::~CDBEnv()
 {
-    EnvShutdown();
+    Close();
 }
 
-void CDBEnv::Close()
-{
-    EnvShutdown();
-}
-
-bool CDBEnv::Open(const fs::path& pathIn, bool retry)
+bool CDBEnv::Open(bool retry)
 {
     if (fDbEnvInit)
         return true;
 
     boost::this_thread::interruption_point();
 
-    strPath = pathIn.string();
+    fs::path pathIn = strPath;
+    TryCreateDirectories(pathIn);
     if (!LockDirectory(pathIn, ".walletlock")) {
         LogPrintf("Cannot obtain a lock on wallet directory %s. Another instance of bitcoin may be using it.\n", strPath);
         return false;
@@ -150,7 +181,7 @@ bool CDBEnv::Open(const fs::path& pathIn, bool retry)
                 // failure is ok (well, not really, but it's not worse than what we started with)
             }
             // try opening it again one more time
-            if (!Open(pathIn, false)) {
+            if (!Open(false /* retry */)) {
                 // if it still fails, it probably means we can't even create the database env
                 return false;
             }
@@ -209,12 +240,15 @@ CDBEnv::VerifyResult CDBEnv::Verify(const std::string& strFile, recoverFunc_type
         return RECOVER_FAIL;
 
     // Try to recover:
-    bool fRecovered = (*recoverFunc)(strFile, out_backup_filename);
+    bool fRecovered = (*recoverFunc)(fs::path(strPath) / strFile, out_backup_filename);
     return (fRecovered ? RECOVER_OK : RECOVER_FAIL);
 }
 
-bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& newFilename)
+bool CDB::Recover(const fs::path& file_path, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& newFilename)
 {
+    std::string filename;
+    CDBEnv* env = GetWalletEnv(file_path, filename);
+
     // Recovery procedure:
     // move wallet file to walletfilename.timestamp.bak
     // Call Salvage with fAggressive=true to
@@ -225,7 +259,7 @@ bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*reco
     int64_t now = GetTime();
     newFilename = strprintf("%s.%d.bak", filename, now);
 
-    int result = bitdb.dbenv->dbrename(nullptr, filename.c_str(), nullptr,
+    int result = env->dbenv->dbrename(nullptr, filename.c_str(), nullptr,
                                        newFilename.c_str(), DB_AUTO_COMMIT);
     if (result == 0)
         LogPrintf("Renamed %s to %s\n", filename, newFilename);
@@ -236,7 +270,7 @@ bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*reco
     }
 
     std::vector<CDBEnv::KeyValPair> salvagedData;
-    bool fSuccess = bitdb.Salvage(newFilename, true, salvagedData);
+    bool fSuccess = env->Salvage(newFilename, true, salvagedData);
     if (salvagedData.empty())
     {
         LogPrintf("Salvage(aggressive) found no records in %s.\n", newFilename);
@@ -244,7 +278,7 @@ bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*reco
     }
     LogPrintf("Salvage(aggressive) found %u records\n", salvagedData.size());
 
-    std::unique_ptr<Db> pdbCopy = MakeUnique<Db>(bitdb.dbenv.get(), 0);
+    std::unique_ptr<Db> pdbCopy = MakeUnique<Db>(env->dbenv.get(), 0);
     int ret = pdbCopy->open(nullptr,               // Txn pointer
                             filename.c_str(),   // Filename
                             "main",             // Logical db name
@@ -257,7 +291,7 @@ bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*reco
         return false;
     }
 
-    DbTxn* ptxn = bitdb.TxnBegin();
+    DbTxn* ptxn = env->TxnBegin();
     for (CDBEnv::KeyValPair& row : salvagedData)
     {
         if (recoverKVcallback)
@@ -279,8 +313,12 @@ bool CDB::Recover(const std::string& filename, void *callbackDataIn, bool (*reco
     return fSuccess;
 }
 
-bool CDB::VerifyEnvironment(const std::string& walletFile, const fs::path& walletDir, std::string& errorStr)
+bool CDB::VerifyEnvironment(const fs::path& file_path, std::string& errorStr)
 {
+    std::string walletFile;
+    CDBEnv* env = GetWalletEnv(file_path, walletFile);
+    fs::path walletDir = env->Directory();
+
     LogPrintf("Using BerkeleyDB version %s\n", DbEnv::version(0, 0, 0));
     LogPrintf("Using wallet %s\n", walletFile);
 
@@ -291,7 +329,7 @@ bool CDB::VerifyEnvironment(const std::string& walletFile, const fs::path& walle
         return false;
     }
 
-    if (!bitdb.Open(walletDir, true)) {
+    if (!env->Open(true /* retry */)) {
         errorStr = strprintf(_("Error initializing wallet database environment %s!"), walletDir);
         return false;
     }
@@ -299,12 +337,16 @@ bool CDB::VerifyEnvironment(const std::string& walletFile, const fs::path& walle
     return true;
 }
 
-bool CDB::VerifyDatabaseFile(const std::string& walletFile, const fs::path& walletDir, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc)
+bool CDB::VerifyDatabaseFile(const fs::path& file_path, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc)
 {
+    std::string walletFile;
+    CDBEnv* env = GetWalletEnv(file_path, walletFile);
+    fs::path walletDir = env->Directory();
+
     if (fs::exists(walletDir / walletFile))
     {
         std::string backup_filename;
-        CDBEnv::VerifyResult r = bitdb.Verify(walletFile, recoverFunc, backup_filename);
+        CDBEnv::VerifyResult r = env->Verify(walletFile, recoverFunc, backup_filename);
         if (r == CDBEnv::RECOVER_OK)
         {
             warningStr = strprintf(_("Warning: Wallet file corrupt, data salvaged!"
@@ -414,8 +456,8 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
         nFlags |= DB_CREATE;
 
     {
-        LOCK(env->cs_db);
-        if (!env->Open(GetWalletDir()))
+        LOCK(cs_db);
+        if (!env->Open(false /* retry */))
             throw std::runtime_error("CDB: Failed to open database environment.");
 
         pdb = env->mapDb[strFilename];
@@ -442,7 +484,25 @@ CDB::CDB(CWalletDBWrapper& dbw, const char* pszMode, bool fFlushOnCloseIn) : pdb
             if (ret != 0) {
                 throw std::runtime_error(strprintf("CDB: Error %d, can't open database %s", ret, strFilename));
             }
-            CheckUniqueFileid(*env, strFilename, *pdb_temp);
+
+            // Call CheckUniqueFileid on the containing BDB environment to
+            // avoid BDB data consistency bugs that happen when different data
+            // files in the same environment have the same fileid.
+            //
+            // Also call CheckUniqueFileid on all the other g_dbenvs to prevent
+            // bitcoin from opening the same data file through another
+            // environment when the file is referenced through equivalent but
+            // not obviously identical symlinked or hard linked or bind mounted
+            // paths. In the future a more relaxed check for equal inode and
+            // device ids could be done instead, which would allow opening
+            // different backup copies of a wallet at the same time. Maybe even
+            // more ideally, an exclusive lock for accessing the database could
+            // be implemented, so no equality checks are needed at all. (Newer
+            // versions of BDB have an set_lk_exclusive method for this
+            // purpose, but the older version we use does not.)
+            for (auto& env : g_dbenvs) {
+                CheckUniqueFileid(env.second, strFilename, *pdb_temp);
+            }
 
             pdb = pdb_temp.release();
             env->mapDb[strFilename] = pdb;
@@ -490,7 +550,7 @@ void CDB::Close()
         Flush();
 
     {
-        LOCK(env->cs_db);
+        LOCK(cs_db);
         --env->mapFileUseCount[strFile];
     }
 }
@@ -518,7 +578,7 @@ bool CDB::Rewrite(CWalletDBWrapper& dbw, const char* pszSkip)
     const std::string& strFile = dbw.strFile;
     while (true) {
         {
-            LOCK(env->cs_db);
+            LOCK(cs_db);
             if (!env->mapFileUseCount.count(strFile) || env->mapFileUseCount[strFile] == 0) {
                 // Flush log data to the dat file
                 env->CloseDb(strFile);
@@ -646,7 +706,7 @@ bool CDB::PeriodicFlush(CWalletDBWrapper& dbw)
     bool ret = false;
     CDBEnv *env = dbw.env;
     const std::string& strFile = dbw.strFile;
-    TRY_LOCK(bitdb.cs_db,lockDb);
+    TRY_LOCK(cs_db, lockDb);
     if (lockDb)
     {
         // Don't do this if any databases are in use
@@ -694,7 +754,7 @@ bool CWalletDBWrapper::Backup(const std::string& strDest)
     while (true)
     {
         {
-            LOCK(env->cs_db);
+            LOCK(cs_db);
             if (!env->mapFileUseCount.count(strFile) || env->mapFileUseCount[strFile] == 0)
             {
                 // Flush log data to the dat file
diff --git a/src/wallet/db.h b/src/wallet/db.h
index 787135e400..b1ce451534 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -11,6 +11,7 @@
 #include <serialize.h>
 #include <streams.h>
 #include <sync.h>
+#include <util.h>
 #include <version.h>
 
 #include <atomic>
@@ -32,20 +33,19 @@ private:
     // shutdown problems/crashes caused by a static initialized internal pointer.
     std::string strPath;
 
-    void EnvShutdown();
-
 public:
-    mutable CCriticalSection cs_db;
     std::unique_ptr<DbEnv> dbenv;
     std::map<std::string, int> mapFileUseCount;
     std::map<std::string, Db*> mapDb;
 
-    CDBEnv();
+    CDBEnv(const fs::path& env_directory);
     ~CDBEnv();
     void Reset();
 
     void MakeMock();
     bool IsMock() const { return fMockDb; }
+    bool IsInitialized() const { return fDbEnvInit; }
+    fs::path Directory() const { return strPath; }
 
     /**
      * Verify that database file strFile is OK. If it is not,
@@ -56,7 +56,7 @@ public:
     enum VerifyResult { VERIFY_OK,
                         RECOVER_OK,
                         RECOVER_FAIL };
-    typedef bool (*recoverFunc_type)(const std::string& strFile, std::string& out_backup_filename);
+    typedef bool (*recoverFunc_type)(const fs::path& file_path, std::string& out_backup_filename);
     VerifyResult Verify(const std::string& strFile, recoverFunc_type recoverFunc, std::string& out_backup_filename);
     /**
      * Salvage data from a file that Verify says is bad.
@@ -68,7 +68,7 @@ public:
     typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyValPair;
     bool Salvage(const std::string& strFile, bool fAggressive, std::vector<KeyValPair>& vResult);
 
-    bool Open(const fs::path& path, bool retry = 0);
+    bool Open(bool retry);
     void Close();
     void Flush(bool fShutdown);
     void CheckpointLSN(const std::string& strFile);
@@ -85,7 +85,8 @@ public:
     }
 };
 
-extern CDBEnv bitdb;
+/** Get CDBEnv and database filename given a wallet path. */
+CDBEnv* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename);
 
 /** An instance of this class represents one database.
  * For BerkeleyDB this is just a (env, strFile) tuple.
@@ -100,9 +101,33 @@ public:
     }
 
     /** Create DB handle to real database */
-    CWalletDBWrapper(CDBEnv *env_in, const std::string &strFile_in) :
-        nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0), env(env_in), strFile(strFile_in)
+    CWalletDBWrapper(const fs::path& wallet_path, bool mock = false) :
+        nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0)
     {
+        env = GetWalletEnv(wallet_path, strFile);
+        if (mock) {
+            env->Close();
+            env->Reset();
+            env->MakeMock();
+        }
+    }
+
+    /** Return object for accessing database at specified path. */
+    static std::unique_ptr<CWalletDBWrapper> Create(const fs::path& path)
+    {
+        return MakeUnique<CWalletDBWrapper>(path);
+    }
+
+    /** Return object for accessing dummy database with no read/write capabilities. */
+    static std::unique_ptr<CWalletDBWrapper> CreateDummy()
+    {
+        return MakeUnique<CWalletDBWrapper>();
+    }
+
+    /** Return object for accessing temporary in-memory database. */
+    static std::unique_ptr<CWalletDBWrapper> CreateMock()
+    {
+        return MakeUnique<CWalletDBWrapper>("", true /* mock */);
     }
 
     /** Rewrite the entire database on disk, with the exception of key pszSkip if non-zero
@@ -113,10 +138,6 @@ public:
      */
     bool Backup(const std::string& strDest);
 
-    /** Get a name for this database, for debugging etc.
-     */
-    std::string GetName() const { return strFile; }
-
     /** Make sure all changes are flushed to disk.
      */
     void Flush(bool shutdown);
@@ -161,15 +182,15 @@ public:
 
     void Flush();
     void Close();
-    static bool Recover(const std::string& filename, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename);
+    static bool Recover(const fs::path& file_path, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename);
 
     /* flush the wallet passively (TRY_LOCK)
        ideal to be called periodically */
     static bool PeriodicFlush(CWalletDBWrapper& dbw);
     /* verifies the database environment */
-    static bool VerifyEnvironment(const std::string& walletFile, const fs::path& walletDir, std::string& errorStr);
+    static bool VerifyEnvironment(const fs::path& file_path, std::string& errorStr);
     /* verifies the database file */
-    static bool VerifyDatabaseFile(const std::string& walletFile, const fs::path& walletDir, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc);
+    static bool VerifyDatabaseFile(const fs::path& file_path, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc);
 
 public:
     template <typename K, typename T>
@@ -329,7 +350,7 @@ public:
     {
         if (!pdb || activeTxn)
             return false;
-        DbTxn* ptxn = bitdb.TxnBegin();
+        DbTxn* ptxn = env->TxnBegin();
         if (!ptxn)
             return false;
         activeTxn = ptxn;
diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 9ac48bff77..e028cf4210 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -35,7 +35,7 @@ std::string GetWalletHelpString(bool showDebug)
     strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
     strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
     strUsage += HelpMessageOpt("-upgradewallet", _("Upgrade wallet to latest format on startup"));
-    strUsage += HelpMessageOpt("-wallet=<file>", _("Specify wallet file (within data directory)") + " " + strprintf(_("(default: %s)"), DEFAULT_WALLET_DAT));
+    strUsage += HelpMessageOpt("-wallet=<path>", _("Specify wallet database path. Can be specified multiple times to load multiple wallets. Path is interpreted relative to <walletdir> if it is not absolute, and will be created if it does not exist (as a directory containing a wallet.dat file and log files). For backwards compatibility this will also accept names of existing data files in <walletdir>.)"));
     strUsage += HelpMessageOpt("-walletbroadcast", _("Make the wallet broadcast transactions") + " " + strprintf(_("(default: %u)"), DEFAULT_WALLETBROADCAST));
     strUsage += HelpMessageOpt("-walletdir=<dir>", _("Specify directory to hold wallets (default: <datadir>/wallets if it exists, otherwise <datadir>)"));
     strUsage += HelpMessageOpt("-walletnotify=<cmd>", _("Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)"));
@@ -66,7 +66,7 @@ bool WalletParameterInteraction()
         return true;
     }
 
-    gArgs.SoftSetArg("-wallet", DEFAULT_WALLET_DAT);
+    gArgs.SoftSetArg("-wallet", "");
     const bool is_multiwallet = gArgs.GetArgs("-wallet").size() > 1;
 
     if (gArgs.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY) && gArgs.SoftSetBoolArg("-walletbroadcast", false)) {
@@ -230,18 +230,22 @@ bool VerifyWallets()
     std::set<fs::path> wallet_paths;
 
     for (const std::string& walletFile : gArgs.GetArgs("-wallet")) {
-        if (boost::filesystem::path(walletFile).filename() != walletFile) {
-            return InitError(strprintf(_("Error loading wallet %s. -wallet parameter must only specify a filename (not a path)."), walletFile));
-        }
-
-        if (SanitizeString(walletFile, SAFE_CHARS_FILENAME) != walletFile) {
-            return InitError(strprintf(_("Error loading wallet %s. Invalid characters in -wallet filename."), walletFile));
-        }
-
+        // Do some checking on wallet path. It should be either a:
+        //
+        // 1. Path where a directory can be created.
+        // 2. Path to an existing directory.
+        // 3. Path to a symlink to a directory.
+        // 4. For backwards compatibility, the name of a data file in -walletdir.
         fs::path wallet_path = fs::absolute(walletFile, GetWalletDir());
-
-        if (fs::exists(wallet_path) && (!fs::is_regular_file(wallet_path) || fs::is_symlink(wallet_path))) {
-            return InitError(strprintf(_("Error loading wallet %s. -wallet filename must be a regular file."), walletFile));
+        fs::file_type path_type = fs::symlink_status(wallet_path).type();
+        if (!(path_type == fs::file_not_found || path_type == fs::directory_file ||
+              (path_type == fs::symlink_file && fs::is_directory(wallet_path)) ||
+              (path_type == fs::regular_file && fs::path(walletFile).filename() == walletFile))) {
+            return InitError(strprintf(
+                _("Invalid -wallet path '%s'. -wallet path should point to a directory where wallet.dat and "
+                  "database/log.?????????? files can be stored, a location where such a directory could be created, "
+                  "or (for backwards compatibility) the name of an existing data file in -walletdir (%s)"),
+                walletFile, GetWalletDir()));
         }
 
         if (!wallet_paths.insert(wallet_path).second) {
@@ -249,21 +253,21 @@ bool VerifyWallets()
         }
 
         std::string strError;
-        if (!CWalletDB::VerifyEnvironment(walletFile, GetWalletDir().string(), strError)) {
+        if (!CWalletDB::VerifyEnvironment(wallet_path, strError)) {
             return InitError(strError);
         }
 
         if (gArgs.GetBoolArg("-salvagewallet", false)) {
             // Recover readable keypairs:
-            CWallet dummyWallet;
+            CWallet dummyWallet("dummy", CWalletDBWrapper::CreateDummy());
             std::string backup_filename;
-            if (!CWalletDB::Recover(walletFile, (void *)&dummyWallet, CWalletDB::RecoverKeysOnlyFilter, backup_filename)) {
+            if (!CWalletDB::Recover(wallet_path, (void *)&dummyWallet, CWalletDB::RecoverKeysOnlyFilter, backup_filename)) {
                 return false;
             }
         }
 
         std::string strWarning;
-        bool dbV = CWalletDB::VerifyDatabaseFile(walletFile, GetWalletDir().string(), strWarning, strError);
+        bool dbV = CWalletDB::VerifyDatabaseFile(wallet_path, strWarning, strError);
         if (!strWarning.empty()) {
             InitWarning(strWarning);
         }
@@ -284,7 +288,7 @@ bool OpenWallets()
     }
 
     for (const std::string& walletFile : gArgs.GetArgs("-wallet")) {
-        CWallet * const pwallet = CWallet::CreateWalletFromFile(walletFile);
+        CWallet * const pwallet = CWallet::CreateWalletFromFile(walletFile, fs::absolute(walletFile, GetWalletDir()));
         if (!pwallet) {
             return false;
         }
diff --git a/src/wallet/test/accounting_tests.cpp b/src/wallet/test/accounting_tests.cpp
index e6510cc214..7b20bd7b02 100644
--- a/src/wallet/test/accounting_tests.cpp
+++ b/src/wallet/test/accounting_tests.cpp
@@ -13,13 +13,13 @@
 BOOST_FIXTURE_TEST_SUITE(accounting_tests, WalletTestingSetup)
 
 static void
-GetResults(CWallet *wallet, std::map<CAmount, CAccountingEntry>& results)
+GetResults(CWallet& wallet, std::map<CAmount, CAccountingEntry>& results)
 {
     std::list<CAccountingEntry> aes;
 
     results.clear();
-    BOOST_CHECK(wallet->ReorderTransactions() == DB_LOAD_OK);
-    wallet->ListAccountCreditDebit("", aes);
+    BOOST_CHECK(wallet.ReorderTransactions() == DB_LOAD_OK);
+    wallet.ListAccountCreditDebit("", aes);
     for (CAccountingEntry& ae : aes)
     {
         results[ae.nOrderPos] = ae;
@@ -33,28 +33,28 @@ BOOST_AUTO_TEST_CASE(acc_orderupgrade)
     CAccountingEntry ae;
     std::map<CAmount, CAccountingEntry> results;
 
-    LOCK(pwalletMain->cs_wallet);
+    LOCK(m_wallet.cs_wallet);
 
     ae.strAccount = "";
     ae.nCreditDebit = 1;
     ae.nTime = 1333333333;
     ae.strOtherAccount = "b";
     ae.strComment = "";
-    pwalletMain->AddAccountingEntry(ae);
+    m_wallet.AddAccountingEntry(ae);
 
     wtx.mapValue["comment"] = "z";
-    pwalletMain->AddToWallet(wtx);
-    vpwtx.push_back(&pwalletMain->mapWallet[wtx.GetHash()]);
+    m_wallet.AddToWallet(wtx);
+    vpwtx.push_back(&m_wallet.mapWallet[wtx.GetHash()]);
     vpwtx[0]->nTimeReceived = (unsigned int)1333333335;
     vpwtx[0]->nOrderPos = -1;
 
     ae.nTime = 1333333336;
     ae.strOtherAccount = "c";
-    pwalletMain->AddAccountingEntry(ae);
+    m_wallet.AddAccountingEntry(ae);
 
-    GetResults(pwalletMain.get(), results);
+    GetResults(m_wallet, results);
 
-    BOOST_CHECK(pwalletMain->nOrderPosNext == 3);
+    BOOST_CHECK(m_wallet.nOrderPosNext == 3);
     BOOST_CHECK(2 == results.size());
     BOOST_CHECK(results[0].nTime == 1333333333);
     BOOST_CHECK(results[0].strComment.empty());
@@ -65,13 +65,13 @@ BOOST_AUTO_TEST_CASE(acc_orderupgrade)
 
     ae.nTime = 1333333330;
     ae.strOtherAccount = "d";
-    ae.nOrderPos = pwalletMain->IncOrderPosNext();
-    pwalletMain->AddAccountingEntry(ae);
+    ae.nOrderPos = m_wallet.IncOrderPosNext();
+    m_wallet.AddAccountingEntry(ae);
 
-    GetResults(pwalletMain.get(), results);
+    GetResults(m_wallet, results);
 
     BOOST_CHECK(results.size() == 3);
-    BOOST_CHECK(pwalletMain->nOrderPosNext == 4);
+    BOOST_CHECK(m_wallet.nOrderPosNext == 4);
     BOOST_CHECK(results[0].nTime == 1333333333);
     BOOST_CHECK(1 == vpwtx[0]->nOrderPos);
     BOOST_CHECK(results[2].nTime == 1333333336);
@@ -85,8 +85,8 @@ BOOST_AUTO_TEST_CASE(acc_orderupgrade)
         ++tx.nLockTime;  // Just to change the hash :)
         wtx.SetTx(MakeTransactionRef(std::move(tx)));
     }
-    pwalletMain->AddToWallet(wtx);
-    vpwtx.push_back(&pwalletMain->mapWallet[wtx.GetHash()]);
+    m_wallet.AddToWallet(wtx);
+    vpwtx.push_back(&m_wallet.mapWallet[wtx.GetHash()]);
     vpwtx[1]->nTimeReceived = (unsigned int)1333333336;
 
     wtx.mapValue["comment"] = "x";
@@ -95,15 +95,15 @@ BOOST_AUTO_TEST_CASE(acc_orderupgrade)
         ++tx.nLockTime;  // Just to change the hash :)
         wtx.SetTx(MakeTransactionRef(std::move(tx)));
     }
-    pwalletMain->AddToWallet(wtx);
-    vpwtx.push_back(&pwalletMain->mapWallet[wtx.GetHash()]);
+    m_wallet.AddToWallet(wtx);
+    vpwtx.push_back(&m_wallet.mapWallet[wtx.GetHash()]);
     vpwtx[2]->nTimeReceived = (unsigned int)1333333329;
     vpwtx[2]->nOrderPos = -1;
 
-    GetResults(pwalletMain.get(), results);
+    GetResults(m_wallet, results);
 
     BOOST_CHECK(results.size() == 3);
-    BOOST_CHECK(pwalletMain->nOrderPosNext == 6);
+    BOOST_CHECK(m_wallet.nOrderPosNext == 6);
     BOOST_CHECK(0 == vpwtx[2]->nOrderPos);
     BOOST_CHECK(results[1].nTime == 1333333333);
     BOOST_CHECK(2 == vpwtx[0]->nOrderPos);
@@ -116,12 +116,12 @@ BOOST_AUTO_TEST_CASE(acc_orderupgrade)
     ae.nTime = 1333333334;
     ae.strOtherAccount = "e";
     ae.nOrderPos = -1;
-    pwalletMain->AddAccountingEntry(ae);
+    m_wallet.AddAccountingEntry(ae);
 
-    GetResults(pwalletMain.get(), results);
+    GetResults(m_wallet, results);
 
     BOOST_CHECK(results.size() == 4);
-    BOOST_CHECK(pwalletMain->nOrderPosNext == 7);
+    BOOST_CHECK(m_wallet.nOrderPosNext == 7);
     BOOST_CHECK(0 == vpwtx[2]->nOrderPos);
     BOOST_CHECK(results[1].nTime == 1333333333);
     BOOST_CHECK(2 == vpwtx[0]->nOrderPos);
diff --git a/src/wallet/test/wallet_test_fixture.cpp b/src/wallet/test/wallet_test_fixture.cpp
index 18abf9a9db..77ccd0b8d8 100644
--- a/src/wallet/test/wallet_test_fixture.cpp
+++ b/src/wallet/test/wallet_test_fixture.cpp
@@ -6,26 +6,21 @@
 
 #include <rpc/server.h>
 #include <wallet/db.h>
+#include <wallet/wallet.h>
 
 WalletTestingSetup::WalletTestingSetup(const std::string& chainName):
-    TestingSetup(chainName)
+    TestingSetup(chainName), m_wallet("mock", CWalletDBWrapper::CreateMock())
 {
-    bitdb.MakeMock();
     bool fFirstRun;
     g_address_type = OUTPUT_TYPE_DEFAULT;
     g_change_type = OUTPUT_TYPE_DEFAULT;
-    std::unique_ptr<CWalletDBWrapper> dbw(new CWalletDBWrapper(&bitdb, "wallet_test.dat"));
-    pwalletMain = MakeUnique<CWallet>(std::move(dbw));
-    pwalletMain->LoadWallet(fFirstRun);
-    RegisterValidationInterface(pwalletMain.get());
+    m_wallet.LoadWallet(fFirstRun);
+    RegisterValidationInterface(&m_wallet);
 
     RegisterWalletRPCCommands(tableRPC);
 }
 
 WalletTestingSetup::~WalletTestingSetup()
 {
-    UnregisterValidationInterface(pwalletMain.get());
-
-    bitdb.Flush(true);
-    bitdb.Reset();
+    UnregisterValidationInterface(&m_wallet);
 }
diff --git a/src/wallet/test/wallet_test_fixture.h b/src/wallet/test/wallet_test_fixture.h
index c03aec7f87..663836a955 100644
--- a/src/wallet/test/wallet_test_fixture.h
+++ b/src/wallet/test/wallet_test_fixture.h
@@ -15,7 +15,7 @@ struct WalletTestingSetup: public TestingSetup {
     explicit WalletTestingSetup(const std::string& chainName = CBaseChainParams::MAIN);
     ~WalletTestingSetup();
 
-    std::unique_ptr<CWallet> pwalletMain;
+    CWallet m_wallet;
 };
 
 #endif
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index 9db5d63922..41348b50a4 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -36,7 +36,7 @@ typedef std::set<CInputCoin> CoinSet;
 
 BOOST_FIXTURE_TEST_SUITE(wallet_tests, WalletTestingSetup)
 
-static const CWallet testWallet;
+static const CWallet testWallet("dummy", CWalletDBWrapper::CreateDummy());
 static std::vector<COutput> vCoins;
 
 static void add_coin(const CAmount& nValue, int nAge = 6*24, bool fIsFromMe = false, int nInput=0)
@@ -382,7 +382,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // Verify ScanForWalletTransactions picks up transactions in both the old
     // and new block files.
     {
-        CWallet wallet;
+        CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
@@ -397,7 +397,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // Verify ScanForWalletTransactions only picks transactions in the new block
     // file.
     {
-        CWallet wallet;
+        CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
@@ -409,7 +409,7 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     // before the missing block, and success for a key whose creation time is
     // after.
     {
-        CWallet wallet;
+        CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
         vpwallets.insert(vpwallets.begin(), &wallet);
         UniValue keys;
         keys.setArray();
@@ -471,7 +471,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 
     // Import key into wallet and call dumpwallet to create backup file.
     {
-        CWallet wallet;
+        CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
         LOCK(wallet.cs_wallet);
         wallet.mapKeyMetadata[coinbaseKey.GetPubKey().GetID()].nCreateTime = KEY_TIME;
         wallet.AddKeyPubKey(coinbaseKey, coinbaseKey.GetPubKey());
@@ -486,7 +486,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
     // Call importwallet RPC and verify all blocks with timestamps >= BLOCK_TIME
     // were scanned, and no prior blocks were scanned.
     {
-        CWallet wallet;
+        CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
 
         JSONRPCRequest request;
         request.params.setArray();
@@ -516,7 +516,7 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 // debit functions.
 BOOST_FIXTURE_TEST_CASE(coin_mark_dirty_immature_credit, TestChain100Setup)
 {
-    CWallet wallet;
+    CWallet wallet("dummy", CWalletDBWrapper::CreateDummy());
     CWalletTx wtx(&wallet, MakeTransactionRef(coinbaseTxns.back()));
     LOCK2(cs_main, wallet.cs_wallet);
     wtx.hashBlock = chainActive.Tip()->GetBlockHash();
@@ -562,27 +562,25 @@ static int64_t AddTx(CWallet& wallet, uint32_t lockTime, int64_t mockTime, int64
 // expanded to cover more corner cases of smart time logic.
 BOOST_AUTO_TEST_CASE(ComputeTimeSmart)
 {
-    CWallet wallet;
-
     // New transaction should use clock time if lower than block time.
-    BOOST_CHECK_EQUAL(AddTx(wallet, 1, 100, 120), 100);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 1, 100, 120), 100);
 
     // Test that updating existing transaction does not change smart time.
-    BOOST_CHECK_EQUAL(AddTx(wallet, 1, 200, 220), 100);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 1, 200, 220), 100);
 
     // New transaction should use clock time if there's no block time.
-    BOOST_CHECK_EQUAL(AddTx(wallet, 2, 300, 0), 300);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 2, 300, 0), 300);
 
     // New transaction should use block time if lower than clock time.
-    BOOST_CHECK_EQUAL(AddTx(wallet, 3, 420, 400), 400);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 3, 420, 400), 400);
 
     // New transaction should use latest entry time if higher than
     // min(block time, clock time).
-    BOOST_CHECK_EQUAL(AddTx(wallet, 4, 500, 390), 400);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 4, 500, 390), 400);
 
     // If there are future entries, new transaction should use time of the
     // newest entry that is no more than 300 seconds ahead of the clock time.
-    BOOST_CHECK_EQUAL(AddTx(wallet, 5, 50, 600), 300);
+    BOOST_CHECK_EQUAL(AddTx(m_wallet, 5, 50, 600), 300);
 
     // Reset mock time for other tests.
     SetMockTime(0);
@@ -591,12 +589,12 @@ BOOST_AUTO_TEST_CASE(ComputeTimeSmart)
 BOOST_AUTO_TEST_CASE(LoadReceiveRequests)
 {
     CTxDestination dest = CKeyID();
-    LOCK(pwalletMain->cs_wallet);
-    pwalletMain->AddDestData(dest, "misc", "val_misc");
-    pwalletMain->AddDestData(dest, "rr0", "val_rr0");
-    pwalletMain->AddDestData(dest, "rr1", "val_rr1");
+    LOCK(m_wallet.cs_wallet);
+    m_wallet.AddDestData(dest, "misc", "val_misc");
+    m_wallet.AddDestData(dest, "rr0", "val_rr0");
+    m_wallet.AddDestData(dest, "rr1", "val_rr1");
 
-    auto values = pwalletMain->GetDestValues("rr");
+    auto values = m_wallet.GetDestValues("rr");
     BOOST_CHECK_EQUAL(values.size(), 2);
     BOOST_CHECK_EQUAL(values[0], "val_rr0");
     BOOST_CHECK_EQUAL(values[1], "val_rr1");
@@ -608,10 +606,9 @@ public:
     ListCoinsTestingSetup()
     {
         CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
-        ::bitdb.MakeMock();
         g_address_type = OUTPUT_TYPE_DEFAULT;
         g_change_type = OUTPUT_TYPE_DEFAULT;
-        wallet.reset(new CWallet(std::unique_ptr<CWalletDBWrapper>(new CWalletDBWrapper(&bitdb, "wallet_test.dat"))));
+        wallet = MakeUnique<CWallet>("mock", CWalletDBWrapper::CreateMock());
         bool firstRun;
         wallet->LoadWallet(firstRun);
         AddKey(*wallet, coinbaseKey);
@@ -623,8 +620,6 @@ public:
     ~ListCoinsTestingSetup()
     {
         wallet.reset();
-        ::bitdb.Flush(true);
-        ::bitdb.Reset();
     }
 
     CWalletTx& AddTx(CRecipient recipient)
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index a014f5b2a0..0c468878e1 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -45,7 +45,6 @@ OutputType g_address_type = OUTPUT_TYPE_NONE;
 OutputType g_change_type = OUTPUT_TYPE_NONE;
 bool g_wallet_allow_fallback_fee = true; //<! will be defined via chainparams
 
-const char * DEFAULT_WALLET_DAT = "wallet.dat";
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
 /**
@@ -3908,16 +3907,17 @@ std::vector<std::string> CWallet::GetDestValues(const std::string& prefix) const
     return values;
 }
 
-CWallet* CWallet::CreateWalletFromFile(const std::string walletFile)
+CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path& path)
 {
+    const std::string& walletFile = name;
+
     // needed to restore wallet transaction meta data after -zapwallettxes
     std::vector<CWalletTx> vWtx;
 
     if (gArgs.GetBoolArg("-zapwallettxes", false)) {
         uiInterface.InitMessage(_("Zapping all transactions from wallet..."));
 
-        std::unique_ptr<CWalletDBWrapper> dbw(new CWalletDBWrapper(&bitdb, walletFile));
-        std::unique_ptr<CWallet> tempWallet = MakeUnique<CWallet>(std::move(dbw));
+        std::unique_ptr<CWallet> tempWallet = MakeUnique<CWallet>(name, CWalletDBWrapper::Create(path));
         DBErrors nZapWalletRet = tempWallet->ZapWalletTx(vWtx);
         if (nZapWalletRet != DB_LOAD_OK) {
             InitError(strprintf(_("Error loading %s: Wallet corrupted"), walletFile));
@@ -3929,8 +3929,7 @@ CWallet* CWallet::CreateWalletFromFile(const std::string walletFile)
 
     int64_t nStart = GetTimeMillis();
     bool fFirstRun = true;
-    std::unique_ptr<CWalletDBWrapper> dbw(new CWalletDBWrapper(&bitdb, walletFile));
-    CWallet *walletInstance = new CWallet(std::move(dbw));
+    CWallet *walletInstance = new CWallet(name, CWalletDBWrapper::Create(path));
     DBErrors nLoadWalletRet = walletInstance->LoadWallet(fFirstRun);
     if (nLoadWalletRet != DB_LOAD_OK)
     {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 4db45f16ef..3e2d1794d8 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -15,6 +15,7 @@
 #include <validationinterface.h>
 #include <script/ismine.h>
 #include <script/sign.h>
+#include <util.h>
 #include <wallet/crypter.h>
 #include <wallet/walletdb.h>
 #include <wallet/rpcwallet.h>
@@ -67,8 +68,6 @@ static const bool DEFAULT_WALLET_RBF = false;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
 
-extern const char * DEFAULT_WALLET_DAT;
-
 static const int64_t TIMESTAMP_MIN = 0;
 
 class CBlockIndex;
@@ -737,6 +736,14 @@ private:
      */
     bool AddWatchOnly(const CScript& dest) override;
 
+    /**
+     * Wallet filename from wallet=<path> command line or config option.
+     * Used in debug logs and to send RPCs to the right wallet instance when
+     * more than one wallet is loaded.
+     */
+    std::string m_name;
+
+    /** Internal database handle. */
     std::unique_ptr<CWalletDBWrapper> dbw;
 
     /**
@@ -768,14 +775,7 @@ public:
 
     /** Get a name for this wallet for logging/debugging purposes.
      */
-    std::string GetName() const
-    {
-        if (dbw) {
-            return dbw->GetName();
-        } else {
-            return "dummy";
-        }
-    }
+    const std::string& GetName() const { return m_name; }
 
     void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool);
 
@@ -789,14 +789,8 @@ public:
     MasterKeyMap mapMasterKeys;
     unsigned int nMasterKeyMaxID;
 
-    // Create wallet with dummy database handle
-    CWallet(): dbw(new CWalletDBWrapper())
-    {
-        SetNull();
-    }
-
-    // Create wallet with passed-in database handle
-    explicit CWallet(std::unique_ptr<CWalletDBWrapper> dbw_in) : dbw(std::move(dbw_in))
+    /** Construct wallet with specified name and database implementation. */
+    CWallet(std::string name, std::unique_ptr<CWalletDBWrapper> dbw) : m_name(std::move(name)), dbw(std::move(dbw))
     {
         SetNull();
     }
@@ -1116,7 +1110,7 @@ public:
     bool MarkReplaced(const uint256& originalHash, const uint256& newHash);
 
     /* Initializes the wallet, returns a new CWallet instance or a null pointer in case of an error */
-    static CWallet* CreateWalletFromFile(const std::string walletFile);
+    static CWallet* CreateWalletFromFile(const std::string& name, const fs::path& path);
 
     /**
      * Wallet post-init setup
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index c14fbd1e8c..0b0880a2ba 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -771,16 +771,16 @@ void MaybeCompactWalletDB()
 //
 // Try to (very carefully!) recover wallet file if there is a problem.
 //
-bool CWalletDB::Recover(const std::string& filename, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename)
+bool CWalletDB::Recover(const fs::path& wallet_path, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename)
 {
-    return CDB::Recover(filename, callbackDataIn, recoverKVcallback, out_backup_filename);
+    return CDB::Recover(wallet_path, callbackDataIn, recoverKVcallback, out_backup_filename);
 }
 
-bool CWalletDB::Recover(const std::string& filename, std::string& out_backup_filename)
+bool CWalletDB::Recover(const fs::path& wallet_path, std::string& out_backup_filename)
 {
     // recover without a key filter callback
     // results in recovering all record types
-    return CWalletDB::Recover(filename, nullptr, nullptr, out_backup_filename);
+    return CWalletDB::Recover(wallet_path, nullptr, nullptr, out_backup_filename);
 }
 
 bool CWalletDB::RecoverKeysOnlyFilter(void *callbackData, CDataStream ssKey, CDataStream ssValue)
@@ -806,14 +806,14 @@ bool CWalletDB::RecoverKeysOnlyFilter(void *callbackData, CDataStream ssKey, CDa
     return true;
 }
 
-bool CWalletDB::VerifyEnvironment(const std::string& walletFile, const fs::path& walletDir, std::string& errorStr)
+bool CWalletDB::VerifyEnvironment(const fs::path& wallet_path, std::string& errorStr)
 {
-    return CDB::VerifyEnvironment(walletFile, walletDir, errorStr);
+    return CDB::VerifyEnvironment(wallet_path, errorStr);
 }
 
-bool CWalletDB::VerifyDatabaseFile(const std::string& walletFile, const fs::path& walletDir, std::string& warningStr, std::string& errorStr)
+bool CWalletDB::VerifyDatabaseFile(const fs::path& wallet_path, std::string& warningStr, std::string& errorStr)
 {
-    return CDB::VerifyDatabaseFile(walletFile, walletDir, warningStr, errorStr, CWalletDB::Recover);
+    return CDB::VerifyDatabaseFile(wallet_path, warningStr, errorStr, CWalletDB::Recover);
 }
 
 bool CWalletDB::WriteDestData(const std::string &address, const std::string &key, const std::string &value)
diff --git a/src/wallet/walletdb.h b/src/wallet/walletdb.h
index 3691cfcb57..7d754c7284 100644
--- a/src/wallet/walletdb.h
+++ b/src/wallet/walletdb.h
@@ -218,17 +218,17 @@ public:
     DBErrors ZapWalletTx(std::vector<CWalletTx>& vWtx);
     DBErrors ZapSelectTx(std::vector<uint256>& vHashIn, std::vector<uint256>& vHashOut);
     /* Try to (very carefully!) recover wallet database (with a possible key type filter) */
-    static bool Recover(const std::string& filename, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename);
+    static bool Recover(const fs::path& wallet_path, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename);
     /* Recover convenience-function to bypass the key filter callback, called when verify fails, recovers everything */
-    static bool Recover(const std::string& filename, std::string& out_backup_filename);
+    static bool Recover(const fs::path& wallet_path, std::string& out_backup_filename);
     /* Recover filter (used as callback), will only let keys (cryptographical keys) as KV/key-type pass through */
     static bool RecoverKeysOnlyFilter(void *callbackData, CDataStream ssKey, CDataStream ssValue);
     /* Function to determine if a certain KV/key-type is a key (cryptographical key) type */
     static bool IsKeyType(const std::string& strType);
     /* verifies the database environment */
-    static bool VerifyEnvironment(const std::string& walletFile, const fs::path& walletDir, std::string& errorStr);
+    static bool VerifyEnvironment(const fs::path& wallet_path, std::string& errorStr);
     /* verifies the database file */
-    static bool VerifyDatabaseFile(const std::string& walletFile, const fs::path& walletDir, std::string& warningStr, std::string& errorStr);
+    static bool VerifyDatabaseFile(const fs::path& wallet_path, std::string& warningStr, std::string& errorStr);
 
     //! write the hdchain model (external chain child index counter)
     bool WriteHDChain(const CHDChain& chain);
diff --git a/test/functional/feature_config_args.py b/test/functional/feature_config_args.py
index 61abba8082..c6cec0596b 100755
--- a/test/functional/feature_config_args.py
+++ b/test/functional/feature_config_args.py
@@ -37,13 +37,13 @@ class ConfArgsTest(BitcoinTestFramework):
         os.mkdir(new_data_dir)
         self.start_node(0, ['-conf='+conf_file, '-wallet=w1'])
         self.stop_node(0)
-        assert os.path.isfile(os.path.join(new_data_dir, 'regtest', 'wallets', 'w1'))
+        assert os.path.exists(os.path.join(new_data_dir, 'regtest', 'wallets', 'w1'))
 
         # Ensure command line argument overrides datadir in conf
         os.mkdir(new_data_dir_2)
         self.nodes[0].datadir = new_data_dir_2
         self.start_node(0, ['-datadir='+new_data_dir_2, '-conf='+conf_file, '-wallet=w2'])
-        assert os.path.isfile(os.path.join(new_data_dir_2, 'regtest', 'wallets', 'w2'))
+        assert os.path.exists(os.path.join(new_data_dir_2, 'regtest', 'wallets', 'w2'))
 
 if __name__ == '__main__':
     ConfArgsTest().main()
diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index b07e451667..378c06ee59 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -16,7 +16,6 @@ class MultiWalletTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
-        self.extra_args = [['-wallet=w1', '-wallet=w2', '-wallet=w3', '-wallet=w'], []]
         self.supports_cli = True
 
     def run_test(self):
@@ -26,9 +25,42 @@ class MultiWalletTest(BitcoinTestFramework):
         wallet_dir = lambda *p: data_dir('wallets', *p)
         wallet = lambda name: node.get_wallet_rpc(name)
 
-        assert_equal(set(node.listwallets()), {"w1", "w2", "w3", "w"})
-
+        # check wallet.dat is created
         self.stop_nodes()
+        assert_equal(os.path.isfile(wallet_dir('wallet.dat')), True)
+
+        # create symlink to verify wallet directory path can be referenced
+        # through symlink
+        os.mkdir(wallet_dir('w7'))
+        os.symlink('w7', wallet_dir('w7_symlink'))
+
+        # rename wallet.dat to make sure plain wallet file paths (as opposed to
+        # directory paths) can be loaded
+        os.rename(wallet_dir("wallet.dat"), wallet_dir("w8"))
+
+        # restart node with a mix of wallet names:
+        #   w1, w2, w3 - to verify new wallets created when non-existing paths specified
+        #   w          - to verify wallet name matching works when one wallet path is prefix of another
+        #   sub/w5     - to verify relative wallet path is created correctly
+        #   extern/w6  - to verify absolute wallet path is created correctly
+        #   w7_symlink - to verify symlinked wallet path is initialized correctly
+        #   w8         - to verify existing wallet file is loaded correctly
+        #   ''         - to verify default wallet file is created correctly
+        wallet_names = ['w1', 'w2', 'w3', 'w', 'sub/w5', os.path.join(self.options.tmpdir, 'extern/w6'), 'w7_symlink', 'w8', '']
+        extra_args = ['-wallet={}'.format(n) for n in wallet_names]
+        self.start_node(0, extra_args)
+        assert_equal(set(node.listwallets()), set(wallet_names))
+
+        # check that all requested wallets were created
+        self.stop_node(0)
+        for wallet_name in wallet_names:
+            if os.path.isdir(wallet_dir(wallet_name)):
+                assert_equal(os.path.isfile(wallet_dir(wallet_name, "wallet.dat")), True)
+            else:
+                assert_equal(os.path.isfile(wallet_dir(wallet_name)), True)
+
+        # should not initialize if wallet path can't be created
+        self.assert_start_raises_init_error(0, ['-wallet=wallet.dat/bad'], 'Not a directory')
 
         self.assert_start_raises_init_error(0, ['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" does not exist')
         self.assert_start_raises_init_error(0, ['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" is a relative path', cwd=data_dir())
@@ -37,17 +69,13 @@ class MultiWalletTest(BitcoinTestFramework):
         # should not initialize if there are duplicate wallets
         self.assert_start_raises_init_error(0, ['-wallet=w1', '-wallet=w1'], 'Error loading wallet w1. Duplicate -wallet filename specified.')
 
-        # should not initialize if wallet file is a directory
-        os.mkdir(wallet_dir('w11'))
-        self.assert_start_raises_init_error(0, ['-wallet=w11'], 'Error loading wallet w11. -wallet filename must be a regular file.')
-
         # should not initialize if one wallet is a copy of another
-        shutil.copyfile(wallet_dir('w2'), wallet_dir('w22'))
-        self.assert_start_raises_init_error(0, ['-wallet=w2', '-wallet=w22'], 'duplicates fileid')
+        shutil.copyfile(wallet_dir('w8'), wallet_dir('w8_copy'))
+        self.assert_start_raises_init_error(0, ['-wallet=w8', '-wallet=w8_copy'], 'duplicates fileid')
 
         # should not initialize if wallet file is a symlink
-        os.symlink(wallet_dir('w1'), wallet_dir('w12'))
-        self.assert_start_raises_init_error(0, ['-wallet=w12'], 'Error loading wallet w12. -wallet filename must be a regular file.')
+        os.symlink('w8', wallet_dir('w8_symlink'))
+        self.assert_start_raises_init_error(0, ['-wallet=w8_symlink'], 'Invalid -wallet path')
 
         # should not initialize if the specified walletdir does not exist
         self.assert_start_raises_init_error(0, ['-walletdir=bad'], 'Error: Specified -walletdir "bad" does not exist')
@@ -77,15 +105,17 @@ class MultiWalletTest(BitcoinTestFramework):
         self.restart_node(0, ['-walletdir='+competing_wallet_dir])
         self.assert_start_raises_init_error(1, ['-walletdir='+competing_wallet_dir], 'Error initializing wallet database environment')
 
-        self.restart_node(0, self.extra_args[0])
+        self.restart_node(0, extra_args)
 
-        w1 = wallet("w1")
-        w2 = wallet("w2")
-        w3 = wallet("w3")
-        w4 = wallet("w")
+        wallets = [wallet(w) for w in wallet_names]
         wallet_bad = wallet("bad")
 
-        w1.generate(1)
+        # check wallet names and balances
+        wallets[0].generate(1)
+        for wallet_name, wallet in zip(wallet_names, wallets):
+            info = wallet.getwalletinfo()
+            assert_equal(info['immature_balance'], 50 if wallet is wallets[0] else 0)
+            assert_equal(info['walletname'], wallet_name)
 
         # accessing invalid wallet fails
         assert_raises_rpc_error(-18, "Requested wallet does not exist or is not loaded", wallet_bad.getwalletinfo)
@@ -93,24 +123,7 @@ class MultiWalletTest(BitcoinTestFramework):
         # accessing wallet RPC without using wallet endpoint fails
         assert_raises_rpc_error(-19, "Wallet file not specified", node.getwalletinfo)
 
-        # check w1 wallet balance
-        w1_info = w1.getwalletinfo()
-        assert_equal(w1_info['immature_balance'], 50)
-        w1_name = w1_info['walletname']
-        assert_equal(w1_name, "w1")
-
-        # check w2 wallet balance
-        w2_info = w2.getwalletinfo()
-        assert_equal(w2_info['immature_balance'], 0)
-        w2_name = w2_info['walletname']
-        assert_equal(w2_name, "w2")
-
-        w3_name = w3.getwalletinfo()['walletname']
-        assert_equal(w3_name, "w3")
-
-        w4_name = w4.getwalletinfo()['walletname']
-        assert_equal(w4_name, "w")
-
+        w1, w2, w3, w4, *_ = wallets
         w1.generate(101)
         assert_equal(w1.getbalance(), 100)
         assert_equal(w2.getbalance(), 0)