Brings file locking changes from develop

1 files changed, 39 insertions, 12 deletions

diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index e4a3207..40d838c 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -36,6 +36,9 @@
 /* The driver identification number, initialized at runtime */
 static hid_t H5FD_CORE_g = 0;
 
+/* Whether to ignore file locks when disabled (env var value) */
+static htri_t ignore_disabled_file_locks_s = FAIL;
+
 /* The skip list node type.  Represents a region in the file. */
 typedef struct H5FD_core_region_t {
     haddr_t start;              /* Start address of the region          */
@@ -55,6 +58,7 @@ typedef struct H5FD_core_t {
     size_t  increment;          /* multiples for mem allocation         */
     hbool_t backing_store;      /* write to file name on flush          */
     size_t  bstore_page_size;   /* backing store page size              */
+    hbool_t ignore_disabled_file_locks;
     int     fd;                 /* backing store file descriptor        */
     /* Information for determining uniqueness of a file with a backing store */
 #ifndef H5_HAVE_WIN32_API
@@ -407,9 +411,19 @@ done:
 static herr_t
 H5FD__init_package(void)
 {
+    char    *lock_env_var   = NULL;     /* Environment variable pointer */
     herr_t ret_value = SUCCEED;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
+
+    /* Check the use disabled file locks environment variable */
+    lock_env_var = HDgetenv("HDF5_USE_FILE_LOCKING");
+    if(lock_env_var && !HDstrcmp(lock_env_var, "BEST_EFFORT"))
+        ignore_disabled_file_locks_s = TRUE;    /* Override: Ignore disabled locks */
+    else if(lock_env_var && (!HDstrcmp(lock_env_var, "TRUE") || !HDstrcmp(lock_env_var, "1")))
+        ignore_disabled_file_locks_s = FALSE;   /* Override: Don't ignore disabled locks */
+    else
+        ignore_disabled_file_locks_s = FAIL;    /* Environment variable not set, or not set correctly */
 
     if(H5FD_core_init() < 0)
         HGOTO_ERROR(H5E_VFL, H5E_CANTINIT, FAIL, "unable to initialize core VFD")
@@ -691,6 +705,16 @@ H5FD__core_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr
     /* Save file image callbacks */
     file->fi_callbacks = file_image_info.callbacks;
 
+    /* Check the file locking flags in the fapl */
+    if(ignore_disabled_file_locks_s != FAIL)
+        /* The environment variable was set, so use that preferentially */
+        file->ignore_disabled_file_locks = ignore_disabled_file_locks_s;
+    else {
+        /* Use the value in the property list */
+        if(H5P_get(plist, H5F_ACS_IGNORE_DISABLED_FILE_LOCKS_NAME, &file->ignore_disabled_file_locks) < 0)
+            HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get ignore disabled file locks property")
+    }
+
     if(fd >= 0) {
         /* Retrieve information for determining uniqueness of file */
 #ifdef H5_HAVE_WIN32_API
@@ -1509,18 +1533,20 @@ H5FD_core_lock(H5FD_t *_file, hbool_t rw)
      * descriptor, this is a no-op.
      */
     if(file->fd >= 0) {
-
         /* Set exclusive or shared lock based on rw status */
         lock_flags = rw ? LOCK_EX : LOCK_SH;
 
         /* Place a non-blocking lock on the file */
         if(HDflock(file->fd, lock_flags | LOCK_NB) < 0) {
-            if(ENOSYS == errno)
-                HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "file locking disabled on this file system (use HDF5_USE_FILE_LOCKING environment variable to override)")
+            if(file->ignore_disabled_file_locks && ENOSYS == errno) {
+                /* When errno is set to ENOSYS, the file system does not support
+                 * locking, so ignore it.
+                 */
+                errno = 0;
+            }
             else
                 HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to lock file")
         } /* end if */
-
     } /* end if */
 
 done:
@@ -1549,16 +1575,17 @@ H5FD_core_unlock(H5FD_t *_file)
 
     HDassert(file);
 
-    if(file->fd >= 0) {
-
+    if(file->fd >= 0)
         if(HDflock(file->fd, LOCK_UN) < 0) {
-            if(ENOSYS == errno)
-                HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "file locking disabled on this file system (use HDF5_USE_FILE_LOCKING environment variable to override)")
+            if(file->ignore_disabled_file_locks && ENOSYS == errno) {
+                /* When errno is set to ENOSYS, the file system does not support
+                 * locking, so ignore it.
+                 */
+                errno = 0;
+            }
             else
                 HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to unlock file")
-        } /* end if */
-
-    } /* end if */
+        }
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)