[svn-r28626] Brought VFD-level file locking code over from revise_chunks.

Tested on:
    Ubuntu 15.10 (Linux 4.2.0 x86_64) gcc 5.2.1
    serial only
    (these changes have been in revise_chunks for a long time)

1 files changed, 71 insertions, 2 deletions

diff --git a/src/H5FDsec2.c b/src/H5FDsec2.c
index 34527df..bb8f004 100644
--- a/src/H5FDsec2.c
+++ b/src/H5FDsec2.c
@@ -97,6 +97,7 @@ typedef struct H5FD_sec2_t {
      * a single file.
      */
     hbool_t         fam_to_sec2;
+
 } H5FD_sec2_t;
 
 /*
@@ -137,6 +138,8 @@ static herr_t H5FD_sec2_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, hadd
 static herr_t H5FD_sec2_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
             size_t size, const void *buf);
 static herr_t H5FD_sec2_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
+static herr_t H5FD_sec2_lock(H5FD_t *_file, hbool_t rw);
+static herr_t H5FD_sec2_unlock(H5FD_t *_file);
 
 static const H5FD_class_t H5FD_sec2_g = {
     "sec2",                     /* name                 */
@@ -168,8 +171,8 @@ static const H5FD_class_t H5FD_sec2_g = {
     H5FD_sec2_write,            /* write                */
     NULL,                       /* flush                */
     H5FD_sec2_truncate,         /* truncate             */
-    NULL,                       /* lock                 */
-    NULL,                       /* unlock               */
+    H5FD_sec2_lock,             /* lock                 */
+    H5FD_sec2_unlock,           /* unlock               */
     H5FD_FLMAP_DICHOTOMY        /* fl_map               */
 };
 
@@ -901,3 +904,69 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5FD_sec2_truncate() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_sec2_lock
+ *
+ * Purpose:     To place an advisory lock on a file.
+ *		The lock type to apply depends on the parameter "rw":
+ *			TRUE--opens for write: an exclusive lock
+ *			FALSE--opens for read: a shared lock
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Vailin Choi; May 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_sec2_lock(H5FD_t *_file, hbool_t rw)
+{
+    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;	/* VFD file struct */
+    int lock;					/* The type of lock */
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(file);
+
+    /* Determine the type of lock */
+    lock = rw ? LOCK_EX : LOCK_SH;
+    
+    /* Place the lock with non-blocking */
+    if(HDflock(file->fd, lock | LOCK_NB) < 0)
+        HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to flock file")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5FD_sec2_lock() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FD_sec2_unlock
+ *
+ * Purpose:     To remove the existing lock on the file
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Vailin Choi; May 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FD_sec2_unlock(H5FD_t *_file)
+{
+    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;	/* VFD file struct */
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(file);
+
+    if(HDflock(file->fd, LOCK_UN) < 0)
+        HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to flock (unlock) file")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5FD_sec2_unlock() */
+