feat: 增加mount的MS_RDONLY标志的支持

增加mount的MS_RDONLY标志的支持，并修改vfs主要接口相关支持。
1. fatfs lseek接口在分区以MS_RDONLY方式和文件以只读打开时不再能够扩大文件的大小。
2. 直接在镜像中创建storage目录，而不是在挂载根文件系统时创建storage目录。
3. 增加了MS_RDONLY的测试用例。

Close #I3Z1W6

Signed-off-by: Far <yesiyuan2@huawei.com>

fs/vfs/operation/fs_chattr.c

@@ -41,6 +41,8 @@
 #include "stdlib.h"
 #include "sys/stat.h"
 #include "vnode.h"
+#include "fs/mount.h"
+#include <fcntl.h>
 
 /****************************************************************************
  * Static Functions
@@ -69,6 +71,11 @@ int chattr(const char *pathname, struct IATTR *attr)
         goto errout_with_lock;
     }
 
+    if ((vnode->originMount) && (vnode->originMount->mountFlags & MS_RDONLY)) {
+        ret = -EROFS;
+        goto errout_with_lock;
+    }
+
     /* The way we handle the stat depends on the type of vnode that we
      * are dealing with.
      */

fs/vfs/operation/fs_utime.c

@@ -37,9 +37,11 @@
 #include "vfs_config.h"
 #include "sys/stat.h"
 #include "vnode.h"
+#include "fs/mount.h"
 #include "string.h"
 #include "stdlib.h"
 #include "utime.h"
+#include <fcntl.h>
 
 /****************************************************************************
  * Global Functions
@@ -79,6 +81,12 @@ int utime(const char *path, const struct utimbuf *ptimes)
         goto errout_with_path;
     }
 
+    if ((vnode->originMount) && (vnode->originMount->mountFlags & MS_RDONLY)) {
+        VnodeDrop();
+        ret = -EROFS;
+        goto errout_with_path;
+    }
+
     if (vnode->vop && vnode->vop->Chattr) {
         if (ptimes == NULL) {
             /* get current seconds */