From 45b0aa27aa4e17f304ce164a028a86acc00e886a Mon Sep 17 00:00:00 2001
From: Nalin Dahyabhai <nalin@redhat.com>
Date: Wed, 20 Feb 2019 11:26:33 -0500
Subject: [PATCH] Locker.Locked(): clarify that we're checking for write locks

Clarify that Locker.Locked() checks if we have a write lock, since
that's what we care about whenever we check it.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
---
 images.go        | 2 +-
 layers.go        | 2 +-
 lockfile.go      | 2 +-
 lockfile_unix.go | 6 ++++--
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/images.go b/images.go
index 93505f5fb..6001c207b 100644
--- a/images.go
+++ b/images.go
@@ -291,7 +291,7 @@ func (r *imageStore) Save() error {
 		return errors.Wrapf(ErrStoreIsReadOnly, "not allowed to modify the image store at %q", r.imagespath())
 	}
 	if !r.Locked() {
-		return errors.New("image store is not locked")
+		return errors.New("image store is not locked for writing")
 	}
 	rpath := r.imagespath()
 	if err := os.MkdirAll(filepath.Dir(rpath), 0700); err != nil {
diff --git a/layers.go b/layers.go
index d612f0459..4fc20d036 100644
--- a/layers.go
+++ b/layers.go
@@ -378,7 +378,7 @@ func (r *layerStore) Save() error {
 		return errors.Wrapf(ErrStoreIsReadOnly, "not allowed to modify the layer store at %q", r.layerspath())
 	}
 	if !r.Locked() {
-		return errors.New("layer store is not locked")
+		return errors.New("layer store is not locked for writing")
 	}
 	rpath := r.layerspath()
 	if err := os.MkdirAll(filepath.Dir(rpath), 0700); err != nil {
diff --git a/lockfile.go b/lockfile.go
index e3b82fce4..3a1befcbe 100644
--- a/lockfile.go
+++ b/lockfile.go
@@ -35,7 +35,7 @@ type Locker interface {
 	// IsReadWrite() checks if the lock file is read-write
 	IsReadWrite() bool
 
-	// Locked() checks if lock is locked
+	// Locked() checks if lock is locked for writing by a thread in this process
 	Locked() bool
 }
 
diff --git a/lockfile_unix.go b/lockfile_unix.go
index 211227012..7dcde875a 100644
--- a/lockfile_unix.go
+++ b/lockfile_unix.go
@@ -139,9 +139,11 @@ func (l *lockfile) Unlock() {
 	l.stateMutex.Unlock()
 }
 
-// Locked checks if lockfile is locked.
+// Locked checks if lockfile is locked for writing by a thread in this process.
 func (l *lockfile) Locked() bool {
-	return l.locked
+	l.stateMutex.Lock()
+	defer l.stateMutex.Unlock()
+	return l.locked && (l.locktype == unix.F_WRLCK)
 }
 
 // Touch updates the lock file with the UID of the user.