geom_vinum_raid5.h revision 130389 
1/*
2 * Copyright (c) 2004 Lukas Ertl
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/geom/vinum/geom_vinum_raid5.h 130389 2004-06-12 21:16:10Z le $
27 */
28
29#ifndef _GEOM_VINUM_RAID5_H_
30#define	_GEOM_VINUM_RAID5_H_
31
32/*
33 * A single RAID5 request usually needs more than one I/O transaction,
34 * depending on the state of the associated subdisks and the direction of the
35 * transaction (read or write).  Every subrequest of a RAID5 request,
36 * represented by a gv_raid_packet, is defined by a gv_raid5_bit.
37 */
38
39/* A subrequest of a RAID5 read/write operation. */
40struct gv_raid5_bit {
41	struct bio	*bio;		/* BIO of this subrequest. */
42	caddr_t		buf;		/* Data buffer of this subrequest. */
43	int		malloc;		/* Flag if data buffer was malloced. */
44	struct g_consumer *consumer;	/* Consumer to send the BIO to. */
45	TAILQ_ENTRY(gv_raid5_bit) list;	/* Entry in the list of this request. */
46};
47
48/* Container for one or more gv_raid5_bits; represents a RAID5 I/O request. */
49struct gv_raid5_packet {
50	caddr_t	buf;		/* Data buffer of this RAID5 request. */
51	off_t	length;		/* Size of data buffer. */
52	off_t	lockbase;	/* Deny access to our plex offset. */
53	off_t	offset;		/* The drive offset of the subdisk. */
54	int	bufmalloc;	/* Flag if data buffer was malloced. */
55	int	active;		/* Count of active subrequests. */
56	int	rqcount;	/* Count of subrequests. */
57
58	struct bio	*bio;	/* Pointer to the original bio. */
59	caddr_t		 data;	/* Pointer to the original data. */
60
61	struct g_consumer *original;	/* Consumer to the data stripe. */
62	struct g_consumer *parity;	/* Consumer to the parity stripe. */
63
64	/* State of this RAID5 packet. */
65	enum {
66	    SETUP,		/* Newly created. */
67	    VALID,		/* Ready for processing. */
68	    IO,			/* Currently doing I/O. */
69	    FINISH		/* Packet has finished. */
70	} state;
71
72	/* Type of this RAID5 transaction. */
73	enum {
74	    JUNK,		/* Newly created, not valid. */
75	    NORMAL,		/* Normal read or write. */
76	    ISPARITY,		/* Containing only parity data. */
77	    NOPARITY,		/* Parity stripe not available. */
78	    DEGRADED,		/* Data stripe not available. */
79	    COMBINED		/* Data and parity stripes ok, others not. */
80	} type;
81
82	TAILQ_HEAD(,gv_raid5_bit)    bits; /* List of subrequests. */
83	TAILQ_ENTRY(gv_raid5_packet) list; /* Entry in plex's packet list. */
84};
85
86int	gv_build_raid5_req(struct gv_raid5_packet *, struct bio *, caddr_t,
87	    long, off_t);
88void	gv_raid5_done(struct bio *);
89void	gv_raid5_worker(void *);
90struct gv_raid5_packet  *gv_new_raid5_packet(void);
91struct gv_raid5_bit	*gv_new_raid5_bit(void);
92
93#endif /* !_GEOM_VINUM_RAID5_H_ */
94