s3 vfs: Add a destructor to the fsp extension data API

I'm not certain if the dummy pointer is needed in struct vfs_fsp_data,
but I added it to be consistent with the comment below.

3 files changed, 8 insertions, 4 deletions

diff --git a/source3/include/proto.h b/source3/include/proto.h
index e5dbe60e11..1a1f8bef69 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -7317,7 +7317,9 @@ void sys_utmp_claim(const char *username, const char *hostname,
 
 NTSTATUS smb_register_vfs(int version, const char *name, const vfs_op_tuple *vfs_op_tuples);
 bool vfs_init_custom(connection_struct *conn, const char *vfs_object);
-void *vfs_add_fsp_extension_notype(vfs_handle_struct *handle, files_struct *fsp, size_t ext_size);
+void *vfs_add_fsp_extension_notype(vfs_handle_struct *handle,
+				   files_struct *fsp, size_t ext_size,
+				   void (*destroy_fn)(void *p_data));
 void vfs_remove_fsp_extension(vfs_handle_struct *handle, files_struct *fsp);
 void *vfs_memctx_fsp_extension(vfs_handle_struct *handle, files_struct *fsp);
 void *vfs_fetch_fsp_extension(vfs_handle_struct *handle, files_struct *fsp);
diff --git a/source3/include/smb.h b/source3/include/smb.h
index 3da63cfc2b..100ec21031 100644
--- a/source3/include/smb.h
+++ b/source3/include/smb.h
@@ -373,7 +373,9 @@ struct rpc_cli_smbd_conn;
 struct vfs_fsp_data {
     struct vfs_fsp_data *next;
     struct vfs_handle_struct *owner;
-    /* NOTE: This structure contains two pointers so that we can guarantee
+    void (*destroy)(void *p_data);
+    void *_dummy_;
+    /* NOTE: This structure contains four pointers so that we can guarantee
      * that the end of the structure is always both 4-byte and 8-byte aligned.
      */
 };
diff --git a/source3/include/vfs.h b/source3/include/vfs.h
index e9115ab807..228f090600 100644
--- a/source3/include/vfs.h
+++ b/source3/include/vfs.h
@@ -679,8 +679,8 @@ typedef struct vfs_statvfs_struct {
 /* Add a new FSP extension of the given type. Returns a pointer to the
  * extenstion data.
  */
-#define VFS_ADD_FSP_EXTENSION(handle, fsp, type) \
-    vfs_add_fsp_extension_notype(handle, (fsp), sizeof(type))
+#define VFS_ADD_FSP_EXTENSION(handle, fsp, type, destroy_fn)		\
+    vfs_add_fsp_extension_notype(handle, (fsp), sizeof(type), (destroy_fn))
 
 /* Return a pointer to the existing FSP extension data. */
 #define VFS_FETCH_FSP_EXTENSION(handle, fsp) \