fs/inode: add reference to protect filelist of group

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

fs/inode/fs_files.c

@@ -173,8 +173,7 @@ static void task_fssync(FAR struct tcb_s *tcb, FAR void *arg)
   int i;
   int j;
 
-  list = &tcb->group->tg_filelist;
-
+  list = files_getlist(tcb);
   for (i = 0; i < list->fl_rows; i++)
     {
       for (j = 0; j < CONFIG_NFILE_DESCRIPTORS_PER_BLOCK; j++)
@@ -188,6 +187,8 @@ static void task_fssync(FAR struct tcb_s *tcb, FAR void *arg)
             }
         }
     }
+
+  files_putlist(list);
 }
 
 /****************************************************************************
@@ -308,6 +309,7 @@ void files_initlist(FAR struct filelist *list)
    */
 
   list->fl_rows = 1;
+  list->fl_crefs = 1;
   list->fl_files = &list->fl_prefile;
   list->fl_prefile = list->fl_prefiles;
 }
@@ -374,19 +376,47 @@ void files_dumplist(FAR struct filelist *list)
 }
 
 /****************************************************************************
- * Name: files_releaselist
+ * Name: files_getlist
  *
  * Description:
- *   Release a reference to the file list
+ *   Get the list of files by tcb.
+ *
+ * Assumptions:
+ *   Called during task deletion in a safe context.
  *
  ****************************************************************************/
 
-void files_releaselist(FAR struct filelist *list)
+FAR struct filelist *files_getlist(FAR struct tcb_s *tcb)
+{
+  FAR struct filelist *list = &tcb->group->tg_filelist;
+
+  DEBUGASSERT(list->fl_crefs >= 1);
+  list->fl_crefs++;
+
+  return list;
+}
+
+/****************************************************************************
+ * Name: files_putlist
+ *
+ * Description:
+ *   Release the list of files.
+ *
+ * Assumptions:
+ *   Called during task deletion in a safe context.
+ *
+ ****************************************************************************/
+
+void files_putlist(FAR struct filelist *list)
 {
   int i;
   int j;
 
-  DEBUGASSERT(list);
+  DEBUGASSERT(list->fl_crefs >= 1);
+  if (--list->fl_crefs > 0)
+    {
+      return;
+    }
 
   /* Close each file descriptor .. Normally, you would need take the list
    * mutex, but it is safe to ignore the mutex in this context

include/nuttx/fs/fs.h

@@ -495,6 +495,7 @@ struct file
 struct filelist
 {
   uint8_t           fl_rows;    /* The number of rows of fl_files array */
+  uint8_t           fl_crefs;   /* The references to filelist */
   FAR struct file **fl_files;   /* The pointer of two layer file descriptors array */
 
   /* Pre-allocated files to avoid allocator access during thread creation
@@ -875,14 +876,24 @@ void files_initlist(FAR struct filelist *list);
 void files_dumplist(FAR struct filelist *list);
 
 /****************************************************************************
- * Name: files_releaselist
+ * Name: files_getlist
  *
  * Description:
- *   Release a reference to the file list
+ *   Get the list of files by tcb.
  *
  ****************************************************************************/
 
-void files_releaselist(FAR struct filelist *list);
+FAR struct filelist *files_getlist(FAR struct tcb_s *tcb);
+
+/****************************************************************************
+ * Name: files_putlist
+ *
+ * Description:
+ *   Release the list of files.
+ *
+ ****************************************************************************/
+
+void files_putlist(FAR struct filelist * list);
 
 /****************************************************************************
  * Name: files_countlist

sched/group/group_leave.c

@@ -96,7 +96,7 @@ group_release(FAR struct task_group_s *group, uint8_t ttype)
 
   /* Free resources held by the file descriptor list */
 
-  files_releaselist(&group->tg_filelist);
+  files_putlist(&group->tg_filelist);
 
 #ifndef CONFIG_DISABLE_ENVIRON
   /* Release all shared environment variables */