Changeset 3471 for trunk/src

Timestamp:

Sep 16, 2020, 2:06:12 AM (5 years ago)

Author:

bird

Message:

kash: Added comment about async close and stat. Some more logging in that area.

File:

• trunk/src/kash/shfile.c (modified) (7 diffs)

trunk/src/kash/shfile.c

@@ -295 +295 @@
     unsigned idx_next;
     unsigned idx_read;
+    unsigned num_pending = 0;
+    unsigned num_threads = 0;
     shmtxtmp tmp;
     shmtx_enter(&g_shfile_async_close.mtx, &tmp);
@@ -304 +306 @@
     if (idx_next != idx_read)
     {
-        unsigned num_pending, num_threads;
-
         /* Write the handle to the ring buffer: */
         assert(g_shfile_async_close.handles[idx] == NULL);
@@ -322 +322 @@
             if (num_pending > num_threads && num_threads < K_ELEMENTS(g_shfile_async_close.threads))
             {
+                int const savederrno = errno;
                 unsigned tid = 0;
                 intptr_t hThread = _beginthreadex(NULL /*security*/, 0 /*stack_size*/, shfile_async_close_handle_thread,
@@ -329 +330 @@
                 {
                     g_shfile_async_close.threads[num_threads] = (HANDLE)hThread;
-                    g_shfile_async_close.num_threads = num_threads + 1;
+                    g_shfile_async_close.num_threads = ++num_threads;
                 }
-                else if (num_threads == 0)
-                    ret = K_FALSE;
+                else
+                {
+                    TRACE2((NULL, "shfile_async_close_submit: _beginthreadex failed: %d\n", errno));
+                    if (num_threads == 0)
+                        ret = K_FALSE;
+                }
+                errno = savederrno;
             }
         }
+        else
+            TRACE2((NULL, "shfile_async_close_submit: SetEvent(%p) failed: %u\n", g_shfile_async_close.evt_workers, GetLastError()));
 
         /* cleanup on failure. */
@@ -350 +358 @@
 
     shmtx_leave(&g_shfile_async_close.mtx, &tmp);
+    TRACE2((NULL, "shfile_async_close_submit: toclose=%p idx=%d #pending=%u #thread=%u -> %d\n",
+            toclose, idx, num_pending, num_threads, ret));
     return ret;
 }
@@ -376 +386 @@
         shmtx_leave(&g_shfile_async_close.mtx, &tmp);
 
+        TRACE2((NULL, "shfile_async_close_sync: Calling WaitForSingleObject...\n"));
         dwRet = WaitForSingleObject(g_shfile_async_close.evt_sync, 10000 /*ms*/);
         assert(dwRet == WAIT_OBJECT_0);
         assert(g_shfile_async_close.num_pending == 0);
+        TRACE2((NULL, "shfile_async_close_sync: WaitForSingleObject returned %u...\n", dwRet));
     }
     else
@@ -405 +417 @@
      * So, detect problematic handles and do CloseHandle asynchronously.   When
      * executing a child process, we probably will have to make sure the CloseHandle
-     * operation has completed before we let do ResumeThread on the child to make
-     * 100% sure we can't have any sharing conflicts.  Sharing conflicts are not a
-     * problem for builtin commands.
+     * operation has completed before we do ResumeThread on the child to make 100%
+     * sure we can't have any sharing conflicts or end up with incorrect CRT stat()
+     * results.  Sharing conflicts are not a problem for builtin commands, and for
+     * stat we do not use the CRT code but ntstat.c/h and it seems to work fine
+     * (might be a tiny bit slower, so (TODO) might be worth reducing what we ask for).
      *
      * If child processes are spawned using handle inheritance and the handle in