block/copy-before-write.h

   1 /*
   2  * copy-before-write filter driver
   3  *
   4  * The driver performs Copy-Before-Write (CBW) operation: it is injected above
   5  * some node, and before each write it copies _old_ data to the target node.
   6  *
   7  * Copyright (c) 2018-2021 Virtuozzo International GmbH.
   8  *
   9  * Author:
  10  *  Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 #ifndef COPY_BEFORE_WRITE_H
  27 #define COPY_BEFORE_WRITE_H
  28
  29 #include "block/block_int.h"
  30 #include "block/block-copy.h"
  31
  32 /*
  33  * Global state (GS) API. These functions run under the BQL.
  34  *
  35  * See include/block/block-global-state.h for more information about
  36  * the GS API.
  37  */
  38
  39 BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
  40                                   BlockDriverState *target,
  41                                   const char *filter_node_name,
  42                                   BlockCopyState **bcs,
  43                                   Error **errp);
  44 void bdrv_cbw_drop(BlockDriverState *bs);
  45
  46 #endif /* COPY_BEFORE_WRITE_H */