qemu/include/block/export.h
Kevin Wolf 1600ef01ab block/export: Add option to allow export of inactive nodes
Add an option in BlockExportOptions to allow creating an export on an
inactive node without activating the node. This mode needs to be
explicitly supported by the export type (so that it doesn't perform any
operations that are forbidden for inactive nodes), so this patch alone
doesn't allow this option to be successfully used yet.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20250204211407.381505-13-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2025-02-06 14:46:40 +01:00

94 lines
2.6 KiB
C

/*
* Declarations for block exports
*
* Copyright (c) 2012, 2020 Red Hat, Inc.
*
* Authors:
* Paolo Bonzini <pbonzini@redhat.com>
* Kevin Wolf <kwolf@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#ifndef BLOCK_EXPORT_H
#define BLOCK_EXPORT_H
#include "qapi/qapi-types-block-export.h"
#include "qemu/queue.h"
typedef struct BlockExport BlockExport;
typedef struct BlockExportDriver {
/* The export type that this driver services */
BlockExportType type;
/*
* The size of the driver-specific state that contains BlockExport as its
* first field.
*/
size_t instance_size;
/* True if the export type supports running on an inactive node */
bool supports_inactive;
/* Creates and starts a new block export */
int (*create)(BlockExport *, BlockExportOptions *, Error **);
/*
* Frees a removed block export. This function is only called after all
* references have been dropped.
*/
void (*delete)(BlockExport *);
/*
* Start to disconnect all clients and drop other references held
* internally by the export driver. When the function returns, there may
* still be active references while the export is in the process of
* shutting down.
*/
void (*request_shutdown)(BlockExport *);
} BlockExportDriver;
struct BlockExport {
const BlockExportDriver *drv;
/* Unique identifier for the export */
char *id;
/*
* Reference count for this block export. This includes strong references
* both from the owner (qemu-nbd or the monitor) and clients connected to
* the export.
*
* Use atomics to access this field.
*/
int refcount;
/*
* True if one of the references in refcount belongs to the user. After the
* user has dropped their reference, they may not e.g. remove the same
* export a second time (which would decrease the refcount without having
* it incremented first).
*/
bool user_owned;
/* The AioContext whose lock protects this BlockExport object. */
AioContext *ctx;
/* The block device to export */
BlockBackend *blk;
/* List entry for block_exports */
QLIST_ENTRY(BlockExport) next;
};
BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp);
BlockExport *blk_exp_find(const char *id);
void blk_exp_ref(BlockExport *exp);
void blk_exp_unref(BlockExport *exp);
void blk_exp_request_shutdown(BlockExport *exp);
void blk_exp_close_all(void);
void blk_exp_close_all_type(BlockExportType type);
#endif