freebsd-dev/usr.sbin/bhyve/block_if.h
John Baldwin 8794846a91 bhyve: Add support for handling disk resize events to block_if.
Allow clients of blockif to register a resize callback handler.  When
a callback is registered, register an EVFILT_VNODE kevent watching the
backing store for a change in the file's attributes.  If the size has
changed when the kevent fires, invoke the clients' callback.

Currently resize detection is limited to backing stores that support
EVFILT_VNODE kevents such as regular files.

Reviewed by:	grehan, markj
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D30504
2021-06-11 18:00:24 -07:00

97 lines
3.6 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* The block API to be used by bhyve block-device emulations. The routines
* are thread safe, with no assumptions about the context of the completion
* callback - it may occur in the caller's context, or asynchronously in
* another thread.
*/
#ifndef _BLOCK_IF_H_
#define _BLOCK_IF_H_
#include <sys/nv.h>
#include <sys/uio.h>
#include <sys/unistd.h>
struct vm_snapshot_meta;
/*
* BLOCKIF_IOV_MAX is the maximum number of scatter/gather entries in
* a single request. BLOCKIF_RING_MAX is the maxmimum number of
* pending requests that can be queued.
*/
#define BLOCKIF_IOV_MAX 128 /* not practical to be IOV_MAX */
#define BLOCKIF_RING_MAX 128
struct blockif_req {
int br_iovcnt;
off_t br_offset;
ssize_t br_resid;
void (*br_callback)(struct blockif_req *req, int err);
void *br_param;
struct iovec br_iov[BLOCKIF_IOV_MAX];
};
struct blockif_ctxt;
typedef void blockif_resize_cb(struct blockif_ctxt *, void *, size_t);
int blockif_legacy_config(nvlist_t *nvl, const char *opts);
struct blockif_ctxt *blockif_open(nvlist_t *nvl, const char *ident);
int blockif_register_resize_callback(struct blockif_ctxt *bc,
blockif_resize_cb *cb, void *cb_arg);
off_t blockif_size(struct blockif_ctxt *bc);
void blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h,
uint8_t *s);
int blockif_sectsz(struct blockif_ctxt *bc);
void blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off);
int blockif_queuesz(struct blockif_ctxt *bc);
int blockif_is_ro(struct blockif_ctxt *bc);
int blockif_candelete(struct blockif_ctxt *bc);
int blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq);
int blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq);
int blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq);
int blockif_delete(struct blockif_ctxt *bc, struct blockif_req *breq);
int blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq);
int blockif_close(struct blockif_ctxt *bc);
#ifdef BHYVE_SNAPSHOT
void blockif_pause(struct blockif_ctxt *bc);
void blockif_resume(struct blockif_ctxt *bc);
int blockif_snapshot_req(struct blockif_req *br,
struct vm_snapshot_meta *meta);
int blockif_snapshot(struct blockif_ctxt *bc,
struct vm_snapshot_meta *meta);
#endif
#endif /* _BLOCK_IF_H_ */