Merge pull request #2798 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:h5f_start_swmr_write_locks to hdf5_1_10

* commit 'dfd5e0bf3e5e360786143bf0486d52120342ef14':
  Brings H5Fstart_swmr_write changes from develop
  Adds fix for H5Fstart_swmr_write lock issue

4 files changed, 45 insertions, 4 deletions

diff --git a/src/H5Fint.c b/src/H5Fint.c
index 9dad1d7..8b9d923 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -1743,6 +1743,15 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id)
     shared = file->shared;
     lf = shared->lf;
 
+    /* Set the file locking flag. If the file is already open, the file
+     * requested file locking flag must match that of the open file.
+     */
+    if(shared->nrefs == 1)
+        file->shared->use_file_locking = use_file_locking;
+    else if(shared->nrefs > 1)
+        if(file->shared->use_file_locking != use_file_locking)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "file locking flag values don't match")
+
     /* Check if page buffering is enabled */
     if(H5P_get(a_plist, H5F_ACS_PAGE_BUFFER_SIZE_NAME, &page_buf_size) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't get page buffer size")
@@ -3541,6 +3550,12 @@ H5F__start_swmr_write(H5F_t *f)
 
     setup = TRUE;
 
+    /* Place an advisory lock on the file */
+    if(H5F_USE_FILE_LOCKING(f))
+        if(H5FD_lock(f->shared->lf, TRUE) < 0) {
+            HGOTO_ERROR(H5E_FILE, H5E_CANTLOCKFILE, FAIL, "unable to lock the file")
+        }
+
     /* Mark superblock as dirty */
     if(H5F_super_dirty(f) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")
@@ -3558,10 +3573,6 @@ H5F__start_swmr_write(H5F_t *f)
         if(H5O_refresh_metadata_reopen(obj_ids[u], &obj_glocs[u], TRUE) < 0)
             HGOTO_ERROR(H5E_ATOM, H5E_CLOSEERROR, FAIL, "can't refresh-close object")
 
-    /* Unlock the file */
-    if(H5FD_unlock(f->shared->lf) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to unlock the file")
-
 done:
     if(ret_value < 0 && setup) {
 
@@ -3590,6 +3601,11 @@ done:
             HDONE_ERROR(H5E_FILE, H5E_CANTFLUSH, FAIL, "unable to flush superblock")
     } /* end if */
 
+    /* Unlock the file */
+    if(H5F_USE_FILE_LOCKING(f))
+        if(H5FD_unlock(f->shared->lf) < 0)
+            HDONE_ERROR(H5E_FILE, H5E_CANTUNLOCKFILE, FAIL, "unable to unlock the file")
+
     /* Free memory */
     if(obj_ids)
         H5MM_xfree(obj_ids);
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 14c00e1..cc37d19 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -306,6 +306,7 @@ struct H5F_shared_t {
     struct H5G_t *root_grp;	/* Open root group			*/
     H5FO_t *open_objs;          /* Open objects in file                 */
     H5UC_t *grp_btree_shared;   /* Ref-counted group B-tree node info   */
+    hbool_t     use_file_locking; /* Whether or not to use file locking */
 
     /* File space allocation information */
     H5F_fspace_strategy_t fs_strategy; /* File space handling strategy	*/
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index fd161e2..469a37c 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -336,6 +336,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_EOA_PRE_FSM_FSALLOC(F) ((F)->shared->eoa_pre_fsm_fsalloc)
 #define H5F_GET_MIN_DSET_OHDR(F) ((F)->shared->crt_dset_min_ohdr_flag)
 #define H5F_SET_MIN_DSET_OHDR(F, V) ((F)->shared->crt_dset_min_ohdr_flag = (V))
+#define H5F_USE_FILE_LOCKING(F) ((F)->shared->use_file_locking)
 #else /* H5F_MODULE */
 #define H5F_LOW_BOUND(F)        (H5F_get_low_bound(F))
 #define H5F_HIGH_BOUND(F)       (H5F_get_high_bound(F))
@@ -397,6 +398,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_EOA_PRE_FSM_FSALLOC(F) (H5F_get_eoa_pre_fsm_fsalloc(F))
 #define H5F_GET_MIN_DSET_OHDR(F) (H5F_get_min_dset_ohdr(F))
 #define H5F_SET_MIN_DSET_OHDR(F, V) (H5F_set_min_dset_ohdr((F), (V)))
+#define H5F_USE_FILE_LOCKING(F) (H5F_get_use_file_locking(F))
 #endif /* H5F_MODULE */
 
 
@@ -756,6 +758,7 @@ H5_DLL hbool_t H5F_get_first_alloc_dealloc(const H5F_t *f);
 H5_DLL haddr_t H5F_get_eoa_pre_fsm_fsalloc(const H5F_t *f);
 H5_DLL hbool_t H5F_get_min_dset_ohdr(const H5F_t *f);
 H5_DLL herr_t H5F_set_min_dset_ohdr(H5F_t *f, hbool_t minimize);
+H5_DLL hbool_t H5F_get_file_locking(const H5F_t *f);
 
 /* Functions than retrieve values set/cached from the superblock/FCPL */
 H5_DLL haddr_t H5F_get_base_addr(const H5F_t *f);
diff --git a/src/H5Fquery.c b/src/H5Fquery.c
index 4125a23..32587bf 100644
--- a/src/H5Fquery.c
+++ b/src/H5Fquery.c
@@ -1302,3 +1302,24 @@ H5F_get_eoa_pre_fsm_fsalloc(const H5F_t *f)
     FUNC_LEAVE_NOAPI(f->shared->eoa_pre_fsm_fsalloc)
 } /* end H5F_get_eoa_pre_fsm_fsalloc() */
 
+
+/*-------------------------------------------------------------------------
+ * Function: H5F_get_file_locking
+ *
+ * Purpose:  Get the file locking flag for the file
+ *
+ * Return:   TRUE/FALSE
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5F_get_file_locking(const H5F_t *f)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->use_file_locking)
+} /* end H5F_get_file_locking */
+