diff --git a/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c b/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
index afb2a0d46d97..6c8de2b01877 100644
--- a/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
+++ b/components/dfs/dfs_v1/filesystems/elmfat/dfs_elm.c
@@ -584,6 +584,11 @@ int dfs_elm_flush(struct dfs_file *file)
     FIL *fd;
     FRESULT result;
 
+    if (file->vnode->type == FT_DIRECTORY)
+    {
+        return -EISDIR;
+    }
+
     fd = (FIL *)(file->data);
     RT_ASSERT(fd != RT_NULL);
 
diff --git a/components/dfs/dfs_v1/src/dfs_posix.c b/components/dfs/dfs_v1/src/dfs_posix.c
index f3d7b70c318e..9e113077098e 100644
--- a/components/dfs/dfs_v1/src/dfs_posix.c
+++ b/components/dfs/dfs_v1/src/dfs_posix.c
@@ -460,6 +460,11 @@ int fsync(int fildes)
     }
 
     ret = dfs_file_flush(d);
+    if (ret < 0)
+    {
+        rt_set_errno(ret);
+        return -1;
+    }
 
     return ret;
 }
diff --git a/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c b/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
index cb1479f6ca9e..51014b09522f 100644
--- a/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
+++ b/components/dfs/dfs_v2/filesystems/elmfat/dfs_elm.c
@@ -619,6 +619,11 @@ int dfs_elm_flush(struct dfs_file *file)
     FIL *fd;
     FRESULT result;
 
+    if (file->vnode->type == FT_DIRECTORY)
+    {
+        return -EISDIR;
+    }
+
     fd = (FIL *)(file->vnode->data);
     RT_ASSERT(fd != RT_NULL);
 
diff --git a/components/dfs/dfs_v2/src/dfs_file.c b/components/dfs/dfs_v2/src/dfs_file.c
index 9c6e383e1b41..32a18dab3d8d 100644
--- a/components/dfs/dfs_v2/src/dfs_file.c
+++ b/components/dfs/dfs_v2/src/dfs_file.c
@@ -2202,6 +2202,7 @@ int dfs_file_rename(const char *old_file, const char *new_file)
  * @return int Operation result:
  *         - 0 on success
  *         -EBADF if invalid file descriptor
+ *         -EISDIR if the file is a directory (directories cannot be truncated)
  *         -ENOSYS if truncate operation not supported
  *         -EINVAL if invalid parameters or not mounted
  *
@@ -2214,6 +2215,11 @@ int dfs_file_ftruncate(struct dfs_file *file, off_t length)
 
     if (file)
     {
+        if (file->vnode->type == FT_DIRECTORY)
+        {
+            return -EISDIR;
+        }
+
         if (file->fops->truncate)
         {
             if (dfs_is_mounted(file->vnode->mnt) == 0)
diff --git a/components/dfs/dfs_v2/src/dfs_posix.c b/components/dfs/dfs_v2/src/dfs_posix.c
index d0eff53a4673..f774aee341d9 100644
--- a/components/dfs/dfs_v2/src/dfs_posix.c
+++ b/components/dfs/dfs_v2/src/dfs_posix.c
@@ -605,6 +605,11 @@ int fsync(int fildes)
     }
 
     ret = dfs_file_fsync(file);
+    if (ret < 0)
+    {
+        rt_set_errno(ret);
+        return -1;
+    }
 
     return ret;
 }