diff --git a/third_party/github.com/cznic/kv/all_test.go b/third_party/github.com/cznic/kv/all_test.go
index de489ba98..4c8e1c853 100644
--- a/third_party/github.com/cznic/kv/all_test.go
+++ b/third_party/github.com/cznic/kv/all_test.go
@@ -123,6 +123,7 @@ func TestClose(t *testing.T) {
 		os.Remove(o._WAL)
 	}(db.Name())
 
+	go db.Close()
 	if err := db.Close(); err != nil {
 		t.Error(err)
 		return
diff --git a/third_party/github.com/cznic/kv/doc.go b/third_party/github.com/cznic/kv/doc.go
index 791553327..ba7cb9b96 100644
--- a/third_party/github.com/cznic/kv/doc.go
+++ b/third_party/github.com/cznic/kv/doc.go
@@ -9,12 +9,17 @@ Package kv implements a simple and easy to use persistent key/value (KV) store.
 The stored KV pairs are sorted in the key collation order defined by an user
 supplied 'compare' function (passed as a field in Options).
 
-Keys and Values
+Keys and Values Limits
 
 Keys, as well as the values associated with them, are opaque []bytes. Maximum
 size of a "native" key or value is 65787 bytes. Larger keys or values have to
 be composed of the "native" ones in client code.
 
+Database limits
+
+The maximum DB size kv can handle is 2^60 bytes (1 exabyte). See also [4]:
+"Block handles".
+
 ACID and transactional properties
 
 Transactions are resource limited. All changes made by a transaction are held
@@ -71,6 +76,7 @@ Referenced from above:
   [1]: http://en.wikipedia.org/wiki/ACID
   [2]: http://en.wikipedia.org/wiki/2PC
   [3]: http://en.wikipedia.org/wiki/Write_ahead_logging
+  [4]: http://godoc.org/github.com/cznic/exp/lldb#Allocator
 
 */
 package kv
diff --git a/third_party/github.com/cznic/kv/kv.go b/third_party/github.com/cznic/kv/kv.go
index e7e636829..ec54105c9 100644
--- a/third_party/github.com/cznic/kv/kv.go
+++ b/third_party/github.com/cznic/kv/kv.go
@@ -241,13 +241,14 @@ func Open(name string, opts *Options) (db *DB, err error) {
 // any. Failing to call Close before exiting a program can lose the last open
 // or being committed transaction.
 //
-// Close is idempotent.
+// Successful Close is idempotent.
 func (db *DB) Close() (err error) {
 	db.closeMu.Lock()
 	defer db.closeMu.Unlock()
 	if db.closed {
-		return nil
+		return
 	}
+
 	db.closed = true
 
 	if err = db.enter(); err != nil {
@@ -301,6 +302,15 @@ func (db *DB) Close() (err error) {
 }
 
 func (db *DB) close() (err error) {
+	// We are safe to close due to locked db.closeMu, but not safe aginst
+	// any other goroutine concurrently calling other exported db methods,
+	// causing a race[0] in the db.enter() mechanism. So we must lock
+	// db.bkl.
+	//
+	//  [0]: https://github.com/cznic/kv/issues/17#issuecomment-31960658
+	db.bkl.Lock()
+	defer db.bkl.Unlock()
+
 	if db.f == nil { // lldb.MemFiler
 		return
 	}
@@ -424,6 +434,8 @@ func (db *DB) timeout() {
 	db.bkl.Lock()
 	defer db.bkl.Unlock()
 
+	db.closeMu.Lock()
+	defer db.closeMu.Unlock()
 	if db.closed {
 		return
 	}
@@ -581,17 +593,17 @@ func (db *DB) Delete(key []byte) (err error) {
 // Extract is a combination of Get and Delete. If the key exists in the DB, it
 // is returned (like Get) and also deleted from the DB in a more efficient way
 // which doesn't search for the key twice. The returned slice may be a
-// sub-slice of dst if dst was large enough to hold the entire content.
+// sub-slice of buf if buf was large enough to hold the entire content.
 // Otherwise, a newly allocated slice will be returned. It is valid to pass a
-// nil dst.
+// nil buf.
 //
 // Extract is atomic and it is safe for concurrent use by multiple goroutines.
-func (db *DB) Extract(dst, key []byte) (value []byte, err error) {
+func (db *DB) Extract(buf, key []byte) (value []byte, err error) {
 	if err = db.enter(); err != nil {
 		return
 	}
 
-	value, err = db.root.Extract(dst, key)
+	value, err = db.root.Extract(buf, key)
 	db.leave(&err)
 	return
 }
@@ -611,17 +623,17 @@ func (db *DB) First() (key, value []byte, err error) {
 }
 
 // Get returns the value associated with key, or nil if no such value exists.
-// The returned slice may be a sub-slice of dst if dst was large enough to hold
+// The returned slice may be a sub-slice of buf if buf was large enough to hold
 // the entire content. Otherwise, a newly allocated slice will be returned. It
-// is valid to pass a nil dst.
+// is valid to pass a nil buf.
 //
 // Get is atomic and it is safe for concurrent use by multiple goroutines.
-func (db *DB) Get(dst, key []byte) (value []byte, err error) {
+func (db *DB) Get(buf, key []byte) (value []byte, err error) {
 	if err = db.enter(); err != nil {
 		return
 	}
 
-	value, err = db.root.Get(dst, key)
+	value, err = db.root.Get(buf, key)
 	db.leave(&err)
 	return
 }
@@ -655,17 +667,17 @@ func (db *DB) Last() (key, value []byte, err error) {
 //
 // modulo the differing return values.
 //
-// The returned slice may be a sub-slice of dst if dst was large enough to hold
+// The returned slice may be a sub-slice of buf if buf was large enough to hold
 // the entire content. Otherwise, a newly allocated slice will be returned. It
-// is valid to pass a nil dst.
+// is valid to pass a nil buf.
 //
 // Put is atomic and it is safe for concurrent use by multiple goroutines.
-func (db *DB) Put(dst, key []byte, upd func(key, old []byte) (new []byte, write bool, err error)) (old []byte, written bool, err error) {
+func (db *DB) Put(buf, key []byte, upd func(key, old []byte) (new []byte, write bool, err error)) (old []byte, written bool, err error) {
 	if err = db.enter(); err != nil {
 		return
 	}
 
-	old, written, err = db.root.Put(dst, key, upd)
+	old, written, err = db.root.Put(buf, key, upd)
 	db.leave(&err)
 	return
 }
diff --git a/third_party/github.com/cznic/kv/v0.go b/third_party/github.com/cznic/kv/v0.go
index 7d6202c78..39d1c22bb 100644
--- a/third_party/github.com/cznic/kv/v0.go
+++ b/third_party/github.com/cznic/kv/v0.go
@@ -13,7 +13,7 @@ import (
 func open00(name string, in *DB) (db *DB, err error) {
 	db = in
 	if db.alloc, err = lldb.NewAllocator(lldb.NewInnerFiler(db.filer, 16), &lldb.Options{}); err != nil {
-		return nil, &os.PathError{Op: "dbm.Open", Path: name, Err: err}
+		return nil, &os.PathError{Op: "kv.open00", Path: name, Err: err}
 	}
 
 	db.alloc.Compress = true