diff --git a/.gitignore b/.gitignore
index 3b96d13..be3d730 100644
--- a/.gitignore
+++ b/.gitignore
@@ -51,6 +51,7 @@ src/tests/test_server_id_func
 src/tests/test_pipe
 src/tests/test_atomic
 src/tests/test_file_write_hole
+src/tests/test_file_lock
 
 # other
 *.swp
diff --git a/src/tests/Makefile b/src/tests/Makefile
index 5603b50..2cca679 100644
--- a/src/tests/Makefile
+++ b/src/tests/Makefile
@@ -8,7 +8,7 @@ ALL_PRGS = test_allocator test_skiplist test_multi_skiplist test_mblock test_blo
            test_id_generator test_ini_parser test_char_convert test_char_convert_loader \
            test_logger test_skiplist_set test_crc32 test_thourands_seperator test_sched_thread \
            test_json_parser test_pthread_lock test_uniq_skiplist test_split_string \
-           test_server_id_func test_pipe test_atomic test_file_write_hole
+           test_server_id_func test_pipe test_atomic test_file_write_hole test_file_lock
 
 all: $(ALL_PRGS)
 .c:
diff --git a/src/tests/test_file_lock.c b/src/tests/test_file_lock.c
new file mode 100644
index 0000000..adcf5b9
--- /dev/null
+++ b/src/tests/test_file_lock.c
@@ -0,0 +1,188 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <time.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/time.h>
+#include <sys/file.h>
+#include "fastcommon/logger.h"
+#include "fastcommon/shared_func.h"
+
+static inline int get_lock_info(int fd, struct flock *lock)
+{
+    int result;
+
+    memset(lock, 0, sizeof(struct flock));
+    lock->l_whence = SEEK_SET;
+    lock->l_type = F_WRLCK;
+    lock->l_pid = getpid();
+    do {
+        if ((result=fcntl(fd, F_GETLK, lock)) != 0)
+        {
+            result = errno != 0 ? errno : ENOMEM;
+            fprintf(stderr, "call fcntl fail, "
+                   "errno: %d, error info: %s\n",
+                   result, STRERROR(result));
+        }
+    } while (result == EINTR);
+
+    return result;
+}
+
+int main(int argc, char *argv[])
+{
+#define SEEK_POS   (2 * 1024)
+    char *filename;
+    int fd;
+    int result;
+    int sleep_seconds;
+    int n;
+    char buf[1024];
+    struct flock lock;
+
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
+        return 1;
+    }
+
+    log_init();
+    filename = argv[1];
+    if (argc >= 3) {
+        sleep_seconds = atoi(argv[2]);
+    } else {
+        sleep_seconds = 1;
+    }
+
+    fd = open(filename, O_RDWR | O_CREAT, 0644);
+    if (fd < 0) {
+        result = errno != 0 ? errno : EIO;
+        logError("file: "__FILE__", line: %d, "
+            "open file %s fail, "
+            "errno: %d, error info: %s",
+            __LINE__, filename,
+            result, STRERROR(result));
+        return result;
+    }
+
+    if (flock(fd, LOCK_EX) < 0) {
+        logError("file: "__FILE__", line: %d, "
+                "flock file %s fail, "
+                "errno: %d, error info: %s", __LINE__,
+                filename, errno, STRERROR(errno));
+        return errno != 0 ? errno : EIO;
+    }
+
+    do {
+        if (ftruncate(fd, 102400) < 0) {
+            logError("file: "__FILE__", line: %d, "
+                    "ftruncate file %s fail, "
+                    "errno: %d, error info: %s", __LINE__,
+                    filename, errno, STRERROR(errno));
+            result = errno != 0 ? errno : EIO;
+            break;
+        }
+
+        if (lseek(fd, SEEK_POS, SEEK_SET) < 0) {
+            logError("file: "__FILE__", line: %d, "
+                    "lseek file %s fail, "
+                    "errno: %d, error info: %s", __LINE__,
+                    filename, errno, STRERROR(errno));
+            result = errno != 0 ? errno : EIO;
+            break;
+        }
+
+        memset(buf, '\n', sizeof(buf));
+        if ((n=write(fd, buf, sizeof(buf))) <= 0) {
+            logError("file: "__FILE__", line: %d, "
+                    "write to file %s fail, "
+                    "errno: %d, error info: %s", __LINE__,
+                    filename, errno, STRERROR(errno));
+            result = errno != 0 ? errno : EIO;
+            break;
+        }
+        result = 0;
+        logInfo("pid: %d, write bytes: %d", getpid(), n);
+    } while (0);
+
+    sleep(sleep_seconds);
+
+    if ((result=get_lock_info(fd, &lock)) == 0) {
+        logInfo("lock info: { type: %d, whence: %d, start: %"PRId64", "
+                "len: %"PRId64", pid: %d }",
+                lock.l_type, lock.l_whence, (int64_t)lock.l_start,
+                (int64_t)lock.l_len, lock.l_pid);
+    }
+
+    if (flock(fd, LOCK_UN) < 0) {
+        logError("file: "__FILE__", line: %d, "
+                "unlock file %s fail, "
+                "errno: %d, error info: %s", __LINE__,
+                filename, errno, STRERROR(errno));
+        return errno != 0 ? errno : EIO;
+    }
+
+    if (result != 0) {
+        return result;
+    }
+
+    if ((result=get_lock_info(fd, &lock)) == 0) {
+        logInfo("lock info: { type: %d, whence: %d, start: %"PRId64", "
+                "len: %"PRId64", pid: %d }",
+                lock.l_type, lock.l_whence, (int64_t)lock.l_start,
+                (int64_t)lock.l_len, lock.l_pid);
+    }
+
+
+    logInfo("pid: %d, before lock ...", getpid());
+    if ((result=file_read_lock(fd)) != 0) {
+        logError("file: "__FILE__", line: %d, "
+                "lock file %s fail, "
+                "errno: %d, error info: %s", __LINE__,
+                filename, result, STRERROR(result));
+        return result;
+    }
+
+    if ((result=get_lock_info(fd, &lock)) == 0) {
+        logInfo("lock info: { type: %d, whence: %d, start: %"PRId64", "
+                "len: %"PRId64", pid: %d }",
+                lock.l_type, lock.l_whence, (int64_t)lock.l_start,
+                (int64_t)lock.l_len, lock.l_pid);
+    }
+
+
+    logInfo("pid: %d, after lock.", getpid());
+    do {
+        if (lseek(fd, 0, SEEK_SET) < 0) {
+            result = errno != 0 ? errno : EIO;
+            logError("file: "__FILE__", line: %d, "
+                    "lseek file %s fail, "
+                    "errno: %d, error info: %s", __LINE__,
+                    filename, result, STRERROR(result));
+            break;
+        }
+
+        if ((n=read(fd, buf, sizeof(buf))) <= 0) {
+            result = errno != 0 ? errno : EIO;
+            logError("file: "__FILE__", line: %d, "
+                    "read from file %s fail, "
+                    "errno: %d, error info: %s", __LINE__,
+                    filename, result, STRERROR(result));
+            break;
+        }
+    } while (0);
+
+    sleep(sleep_seconds);
+    if ((result=file_unlock(fd)) != 0) {
+        logError("file: "__FILE__", line: %d, "
+                "unlock  file %s fail, "
+                "errno: %d, error info: %s", __LINE__,
+                filename, result, STRERROR(result));
+    }
+
+    logInfo("pid: %d, read bytes: %d, 0 => 0x%02x, %d => 0x%02x\n",
+            getpid(), n, (unsigned char)buf[0], n - 1, (unsigned char)buf[n - 1]);
+    return result;
+}
diff --git a/src/tests/test_file_write_hole.c b/src/tests/test_file_write_hole.c
index 0c508a3..cd96153 100644
--- a/src/tests/test_file_write_hole.c
+++ b/src/tests/test_file_write_hole.c
@@ -26,13 +26,16 @@ int main(int argc, char *argv[])
 
     log_init();
     filename = argv[1];
+    /*
     if (access(filename, F_OK) == 0) {
         logError("file: "__FILE__", line: %d, "
             "file %s already exists", __LINE__, filename);
         return EEXIST;
     }
+    */
 
-    fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
+    //fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
+    fd = open(filename, O_RDWR | O_CREAT, 0644);
     if (fd < 0) {
         result = errno != 0 ? errno : EIO;
         logError("file: "__FILE__", line: %d, " \
@@ -43,6 +46,14 @@ int main(int argc, char *argv[])
         return result;
     }
 
+    if (ftruncate(fd, 102400) < 0) {
+        logError("file: "__FILE__", line: %d, " \
+            "ftruncate file %s fail, " \
+            "errno: %d, error info: %s", __LINE__, \
+            filename, errno, STRERROR(errno));
+        return errno != 0 ? errno : EIO;
+    }
+
     if (lseek(fd, SEEK_POS, SEEK_SET) < 0) {
         logError("file: "__FILE__", line: %d, " \
             "lseek file %s fail, " \