diff --git a/CHANGELOG.md b/CHANGELOG.md
index 371efc085..c5855dad0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,7 +18,8 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
+- [#102](https://github.com/zendframework/zend-cache/pull/102)
+  filesystem: fixes a lot of possible race conditions
 
 ## 2.7.1 - 2016-05-12
 
diff --git a/src/Storage/Adapter/Filesystem.php b/src/Storage/Adapter/Filesystem.php
index 7a645e6c5..6b1896cb2 100644
--- a/src/Storage/Adapter/Filesystem.php
+++ b/src/Storage/Adapter/Filesystem.php
@@ -110,7 +110,14 @@ public function flush()
                     $clearFolder($pathname);
                     rmdir($pathname);
                 } else {
+                    // remove the file by ignoring errors if the file doesn't exist afterwards
+                    // to fix a possible race condition if onother process removed the faile already.
+                    ErrorHandler::start();
                     unlink($pathname);
+                    $err = ErrorHandler::stop();
+                    if ($err && file_exists($pathname)) {
+                        ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+                    }
                 }
             }
         };
@@ -140,7 +147,7 @@ public function clearExpired()
         $namespace = $options->getNamespace();
         $prefix    = ($namespace === '') ? '' : $namespace . $options->getNamespaceSeparator();
 
-        $flags = GlobIterator::SKIP_DOTS | GlobIterator::CURRENT_AS_FILEINFO;
+        $flags = GlobIterator::SKIP_DOTS | GlobIterator::CURRENT_AS_PATHNAME;
         $path  = $options->getCacheDir()
             . str_repeat(DIRECTORY_SEPARATOR . $prefix . '*', $options->getDirLevel())
             . DIRECTORY_SEPARATOR . $prefix . '*.dat';
@@ -149,15 +156,30 @@ public function clearExpired()
         $ttl  = $options->getTtl();
 
         ErrorHandler::start();
-        foreach ($glob as $entry) {
-            $mtime = $entry->getMTime();
-            if ($time >= $mtime + $ttl) {
-                $pathname = $entry->getPathname();
+        foreach ($glob as $pathname) {
+            // get last modification time of the file but ignore if the file is missing
+            // to fix a possible race condition if onother process removed the faile already.
+            ErrorHandler::start();
+            $mtime = filemtime($pathname);
+            $err = ErrorHandler::stop();
+            if ($err && file_exists($pathname)) {
+                ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+            } elseif ($time >= $mtime + $ttl) {
+                // remove the file by ignoring errors if the file doesn't exist afterwards
+                // to fix a possible race condition if onother process removed the faile already.
+                ErrorHandler::start();
                 unlink($pathname);
-
-                $tagPathname = substr($pathname, 0, -4) . '.tag';
-                if (file_exists($tagPathname)) {
+                $err = ErrorHandler::stop();
+                if ($err && file_exists($pathname)) {
+                    ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+                } else {
+                    $tagPathname = substr($pathname, 0, -4) . '.tag';
+                    ErrorHandler::start();
                     unlink($tagPathname);
+                    $err = ErrorHandler::stop();
+                    if ($err && file_exists($pathname)) {
+                        ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+                    }
                 }
             }
         }
@@ -202,11 +224,24 @@ public function clearByNamespace($namespace)
 
         ErrorHandler::start();
         foreach ($glob as $pathname) {
+            // remove the file by ignoring errors if the file doesn't exist afterwards
+            // to fix a possible race condition if onother process removed the faile already.
+            ErrorHandler::start();
             unlink($pathname);
+            $err = ErrorHandler::stop();
+            if ($err && file_exists($pathname)) {
+                ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+            }
         }
-        $error = ErrorHandler::stop();
-        if ($error) {
-            throw new Exception\RuntimeException("Failed to remove files of '{$path}'", 0, $error);
+        $err = ErrorHandler::stop();
+        if ($err) {
+            $result = false;
+            return $this->triggerException(
+                __FUNCTION__,
+                new ArrayObject(),
+                $result,
+                new Exception\RuntimeException("Failed to clear items of namespace '{$namespace}'", 0, $err)
+            );
         }
 
         return true;
@@ -240,11 +275,24 @@ public function clearByPrefix($prefix)
 
         ErrorHandler::start();
         foreach ($glob as $pathname) {
+            // remove the file by ignoring errors if the file doesn't exist afterwards
+            // to fix a possible race condition if onother process removed the faile already.
+            ErrorHandler::start();
             unlink($pathname);
+            $err = ErrorHandler::stop();
+            if ($err && file_exists($pathname)) {
+                ErrorHandler::addError($err->getSeverity(), $err->getMessage(), $err->getFile(), $err->getLine());
+            }
         }
-        $error = ErrorHandler::stop();
-        if ($error) {
-            throw new Exception\RuntimeException("Failed to remove files of '{$path}'", 0, $error);
+        $err = ErrorHandler::stop();
+        if ($err) {
+            $result = false;
+            return $this->triggerException(
+                __FUNCTION__,
+                new ArrayObject(),
+                $result,
+                new Exception\RuntimeException("Failed to remove files of '{$path}'", 0, $err)
+            );
         }
 
         return true;
diff --git a/test/Storage/Adapter/FilesystemTest.php b/test/Storage/Adapter/FilesystemTest.php
index ef0b42dfb..2cf8165bf 100644
--- a/test/Storage/Adapter/FilesystemTest.php
+++ b/test/Storage/Adapter/FilesystemTest.php
@@ -346,15 +346,18 @@ public function testClearByPrefixWithUnexpectedDirectory()
     /**
      * @runInSeparateProcess
      */
-    public function testClearByTagsWithoutLocking()
+    public function testRaceConditionInClearByTags()
     {
         if (!function_exists('pcntl_fork') || !function_exists('posix_kill')) {
             $this->markTestSkipped('Missing pcntl_fork and/or posix_kill');
         }
 
+        // delay unlink() by global variable $unlinkDelay
+        global $unlinkDelay;
+        require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+
         // create cache items
         $this->_storage->getOptions()->setDirLevel(0);
-        $this->_storage->getOptions()->setFileLocking(false);
         $this->_storage->setItems([
             'a_key' => 'a_value',
             'b_key' => 'b_value',
@@ -370,14 +373,15 @@ public function testClearByTagsWithoutLocking()
             // The parent process
             // Slow down unlink function and start removing items.
             // Finally test if the item not matching the tag was removed by the child process.
-            require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+            $unlinkDelay = 5000;
+
             $this->_storage->clearByTags(['a_tag'], true);
-            $this->assertFalse($this->_storage->hasItem('other'));
+            $this->assertFalse($this->_storage->hasItem('other'), 'Child process does not run as expected');
         } else {
             // The child process:
             // Wait to make sure the parent process has started determining files to unlink.
             // Than remove one of the items the parent process should remove and another item for testing.
-            usleep(10000);
+            usleep(1000);
             $this->_storage->removeItems(['b_key', 'other']);
             posix_kill(posix_getpid(), SIGTERM);
         }
@@ -386,22 +390,138 @@ public function testClearByTagsWithoutLocking()
     /**
      * @runInSeparateProcess
      */
-    public function testClearByTagsWithLocking()
+    public function testRaceConditionInClearByNamespace()
+    {
+        if (!function_exists('pcntl_fork') || !function_exists('posix_kill')) {
+            $this->markTestSkipped('Missing pcntl_fork and/or posix_kill');
+        }
+
+        // delay unlink() by global variable $unlinkDelay
+        global $unlinkDelay;
+        require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+
+        // create cache items
+        $this->_storage->getOptions()->setDirLevel(0);
+        $this->_storage->getOptions()->setNamespace('ns-other');
+        $this->_storage->setItems([
+            'other' => 'other',
+        ]);
+        $this->_storage->getOptions()->setNamespace('ns-4-clear');
+        $this->_storage->setItems([
+            'a_key' => 'a_value',
+            'b_key' => 'b_value',
+        ]);
+
+        $pidChild = pcntl_fork();
+        if ($pidChild == -1) {
+            $this->fail('pcntl_fork() failed');
+        } elseif ($pidChild) {
+            // The parent process
+            // Slow down unlink function and start removing items.
+            // Finally test if the item not matching the tag was removed by the child process.
+            $unlinkDelay = 5000;
+
+            $this->_storage->getOptions()->setNamespace('ns-4-clear');
+            $this->_storage->clearByNamespace('ns-4-clear');
+
+            $this->assertFalse($this->_storage->hasItem('a_key'));
+            $this->assertFalse($this->_storage->hasItem('b_key'));
+
+            $this->_storage->getOptions()->setNamespace('ns-other');
+            $this->assertFalse($this->_storage->hasItem('other'), 'Child process does not run as expected');
+        } else {
+            // The child process:
+            // Wait to make sure the parent process has started determining files to unlink.
+            // Than remove one of the items the parent process should remove and another item for testing.
+            usleep(1000);
+
+            $this->_storage->getOptions()->setNamespace('ns-4-clear');
+            $this->assertTrue($this->_storage->removeItem('b_key'));
+
+            $this->_storage->getOptions()->setNamespace('ns-other');
+            $this->assertTrue($this->_storage->removeItem('other'));
+
+            posix_kill(posix_getpid(), SIGTERM);
+        }
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testRaceConditionInClearByPrefix()
+    {
+        if (!function_exists('pcntl_fork') || !function_exists('posix_kill')) {
+            $this->markTestSkipped('Missing pcntl_fork and/or posix_kill');
+        }
+
+        // delay unlink() by global variable $unlinkDelay
+        global $unlinkDelay;
+        require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+
+        // create cache items
+        $this->_storage->getOptions()->setDirLevel(0);
+        $this->_storage->getOptions()->setNamespace('ns');
+        $this->_storage->setItems([
+            'prefix_a_key' => 'a_value',
+            'prefix_b_key' => 'b_value',
+            'other'        => 'other',
+        ]);
+
+        $pidChild = pcntl_fork();
+        if ($pidChild == -1) {
+            $this->fail('pcntl_fork() failed');
+        } elseif ($pidChild) {
+            // The parent process
+            // Slow down unlink function and start removing items.
+            // Finally test if the item not matching the tag was removed by the child process.
+            $unlinkDelay = 5000;
+
+            $this->_storage->clearByPrefix('prefix_');
+
+            $this->assertFalse($this->_storage->hasItem('prefix_a_key'));
+            $this->assertFalse($this->_storage->hasItem('prefix_b_key'));
+
+            $this->assertFalse($this->_storage->hasItem('other'), 'Child process does not run as expected');
+        } else {
+            // The child process:
+            // Wait to make sure the parent process has started determining files to unlink.
+            // Than remove one of the items the parent process should remove and another item for testing.
+            usleep(1000);
+
+            $this->assertTrue($this->_storage->removeItem('prefix_b_key'));
+            $this->assertTrue($this->_storage->removeItem('other'));
+
+            posix_kill(posix_getpid(), SIGTERM);
+        }
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testRaceConditionInClearExpired()
     {
         if (!function_exists('pcntl_fork') || !function_exists('posix_kill')) {
             $this->markTestSkipped('Missing pcntl_fork and/or posix_kill');
         }
 
+        // delay unlink() by global variable $unlinkDelay
+        global $unlinkDelay;
+        require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+
         // create cache items
         $this->_storage->getOptions()->setDirLevel(0);
-        $this->_storage->getOptions()->setFileLocking(true);
+        $this->_storage->getOptions()->setTtl(2);
         $this->_storage->setItems([
             'a_key' => 'a_value',
             'b_key' => 'b_value',
             'other' => 'other',
         ]);
-        $this->_storage->setTags('a_key', ['a_tag']);
-        $this->_storage->setTags('b_key', ['a_tag']);
+
+        // wait TTL seconds and touch item other so this item will not be deleted by clearExpired
+        // and can be used for testing the child process
+        $this->waitForFullSecond();
+        sleep(2);
+        $this->_storage->touchItem('other');
 
         $pidChild = pcntl_fork();
         if ($pidChild == -1) {
@@ -410,15 +530,67 @@ public function testClearByTagsWithLocking()
             // The parent process
             // Slow down unlink function and start removing items.
             // Finally test if the item not matching the tag was removed by the child process.
-            require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
-            $this->_storage->clearByTags(['a_tag'], true);
-            $this->assertFalse($this->_storage->hasItem('other'));
+            $unlinkDelay = 5000;
+
+            $this->_storage->clearExpired();
+
+            $this->assertFalse($this->_storage->hasItem('a_key'));
+            $this->assertFalse($this->_storage->hasItem('b_key'));
+
+            $this->assertFalse($this->_storage->hasItem('other'), 'Child process does not run as expected');
         } else {
             // The child process:
             // Wait to make sure the parent process has started determining files to unlink.
             // Than remove one of the items the parent process should remove and another item for testing.
-            usleep(10000);
-            $this->_storage->removeItems(['b_key', 'other']);
+            usleep(1000);
+
+            $this->assertTrue($this->_storage->removeItem('b_key'));
+            $this->assertTrue($this->_storage->removeItem('other'));
+
+            posix_kill(posix_getpid(), SIGTERM);
+        }
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testRaceConditionInFlush()
+    {
+        if (!function_exists('pcntl_fork') || !function_exists('posix_kill')) {
+            $this->markTestSkipped('Missing pcntl_fork and/or posix_kill');
+        }
+
+        // delay unlink() by global variable $unlinkDelay
+        global $unlinkDelay;
+        require __DIR__ . '/TestAsset/FilesystemDelayedUnlink.php';
+
+        // create cache items
+        $this->_storage->getOptions()->setDirLevel(0);
+        $this->_storage->setItems([
+            'a_key' => 'a_value',
+            'b_key' => 'b_value',
+        ]);
+
+        $pidChild = pcntl_fork();
+        if ($pidChild == -1) {
+            $this->fail('pcntl_fork() failed');
+        } elseif ($pidChild) {
+            // The parent process
+            // Slow down unlink function and start removing items.
+            $unlinkDelay = 5000;
+
+            $this->_storage->flush();
+
+            $this->assertFalse($this->_storage->hasItem('a_key'));
+            $this->assertFalse($this->_storage->hasItem('b_key'));
+        } else {
+            // The child process:
+            // Wait to make sure the parent process has started determining files to unlink.
+            // Than remove one of the items the parent process should remove.
+            usleep(1000);
+
+            $this->assertTrue($this->_storage->removeItem('b_key'));
+
             posix_kill(posix_getpid(), SIGTERM);
         }
     }
diff --git a/test/Storage/Adapter/TestAsset/FilesystemDelayedUnlink.php b/test/Storage/Adapter/TestAsset/FilesystemDelayedUnlink.php
index 75da536a4..64d5cd1e6 100644
--- a/test/Storage/Adapter/TestAsset/FilesystemDelayedUnlink.php
+++ b/test/Storage/Adapter/TestAsset/FilesystemDelayedUnlink.php
@@ -4,10 +4,10 @@
 
 function unlink($path, $context = null)
 {
-    usleep(50000);
-    if ($context) {
-        return \unlink($path, $context);
+    global $unlinkDelay;
+    if (isset($unlinkDelay) && $unlinkDelay > 0) {
+        usleep($unlinkDelay);
     }
 
-    return \unlink($path);
+    return $context ? \unlink($path, $context) : \unlink($path);
 }