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/* $NetBSD: wapbl_replay.h,v 1.1 2008/11/24 16:05:21 joerg Exp $ */
/*-
* Copyright (c) 2003,2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Wasabi Systems, Inc.
*
* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION 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.
*/
#ifndef _SYS_WAPBL_REPLAY_H
#define _SYS_WAPBL_REPLAY_H
#include <sys/types.h>
/* The WAPBL journal layout.
*
* The journal consists of a header followed by a circular buffer
* region. The circular data area is described by the header
* wc_circ_off, wc_circ_size, wc_head and wc_tail fields as bytes
* from the start of the journal header. New records are inserted
* at wc_head and the oldest valid record can be found at wc_tail.
* When ((wc_head == wc_tail) && (wc_head == 0)), the journal is empty.
* The condition of ((wc_head == wc_tail) && (wc_head != 0))
* indicates a full journal, although this condition is rare.
*
* The journal header as well as its records are marked by a 32bit
* type tag and length for ease of parsing. Journal records are
* padded so as to fall on journal device block boundaries.
*/
/*
* The following are the 4 record types used by the journal:
* Each tag indicates journal data organized by one of the
* structures used below.
*/
enum {
WAPBL_WC_HEADER = 0x5741424c, /* "WABL", struct wapbl_wc_header */
WAPBL_WC_INODES, /* struct wapbl_wc_inodelist */
WAPBL_WC_REVOCATIONS, /* struct wapbl_wc_blocklist */
WAPBL_WC_BLOCKS, /* struct wapbl_wc_blocklist */
};
/* null entry (on disk) */
/* This structure isn't used directly, but shares its header
* layout with all the other log structures for the purpose
* of reading a log structure and determining its type
*/
struct wapbl_wc_null {
uint32_t wc_type; /* WAPBL_WC_* */
int32_t wc_len;
uint8_t wc_spare[0]; /* actually longer */
};
/* journal header (on-disk)
* This record is found at the start of the
* journal, but not within the circular buffer region. As well as
* describing the journal parameters and matching filesystem, it
* additionally serves as the atomic update record for journal
* updates.
*/
struct wapbl_wc_header {
uint32_t wc_type; /* WAPBL_WC_HEADER log magic number */
int32_t wc_len; /* length of this journal entry */
uint32_t wc_checksum;
uint32_t wc_generation;
int32_t wc_fsid[2];
uint64_t wc_time;
uint32_t wc_timensec;
uint32_t wc_version;
uint32_t wc_log_dev_bshift;
uint32_t wc_fs_dev_bshift;
int64_t wc_head;
int64_t wc_tail;
int64_t wc_circ_off; /* offset of of circ buffer region */
int64_t wc_circ_size; /* size of circular buffer region */
uint8_t wc_spare[0]; /* actually longer */
};
/* list of blocks (on disk)
* This record is used to describe a set of filesystem blocks,
* and is used with two type tags, WAPBL_WC_BLOCKS and
* WAPBL_WC_REVOCATIONS.
*
* For WAPBL_WC_BLOCKS, a copy of each listed block can be found
* starting at the next log device blocksize boundary. starting at
* one log device block since the start of the record. This contains
* the bulk of the filesystem journal data which is written using
* these records before being written into the filesystem.
*
* The WAPBL_WC_REVOCATIONS record is used to indicate that any
* previously listed blocks should not be written into the filesystem.
* This is important so that deallocated and reallocated data blocks
* do not get overwritten with stale data from the journal. The
* revocation records do not contain a copy of any actual block data.
*/
struct wapbl_wc_blocklist {
uint32_t wc_type; /* WAPBL_WC_{REVOCATIONS,BLOCKS} */
int32_t wc_len;
int32_t wc_blkcount;
int32_t wc_unused;
struct {
int64_t wc_daddr;
int32_t wc_unused;
int32_t wc_dlen;
} wc_blocks[0]; /* actually longer */
};
/* list of inodes (on disk)
* This record is used to describe the set of inodes which
* may be allocated but are unlinked. Inodes end up listed here
* while they are in the process of being initialized and
* deinitialized. Inodes unlinked while in use by a process
* will be listed here and the actual deletion must be completed
* on journal replay.
*/
struct wapbl_wc_inodelist {
uint32_t wc_type; /* WAPBL_WC_INODES */
int32_t wc_len;
int32_t wc_inocnt;
int32_t wc_clear; /* set if previously listed inodes
hould be ignored */
struct {
uint32_t wc_inumber;
uint32_t wc_imode;
} wc_inodes[0]; /* actually longer */
};
#endif /* _SYS_WAPBL_REPLAY_H */
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