/*-
* Copyright (c) 1997, 1998
* Nan Yang Computer Services Limited. All rights reserved.
*
* This software is distributed under the so-called ``Berkeley
* License'':
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Nan Yang Computer
* Services Limited.
* 4. Neither the name of the Company nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* This software is provided ``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 company 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.
*
* $Id: request.h,v 1.10 1998/08/03 07:15:26 grog Exp grog $
*/
/* Information needed to set up a transfer */
/* struct buf is surprisingly big (about 300
* bytes), and it's part of the request, so this
* value is really important. Most requests
* don't need more than 2 subrequests per
* plex. The table is automatically extended if
* this value is too small. */
#define RQELTS 2 /* default of 2 requests per transfer */
enum xferinfo {
XFR_NORMAL_READ = 1,
XFR_NORMAL_WRITE = 2, /* write request in normal mode */
XFR_RECOVERY_READ = 4,
XFR_DEGRADED_WRITE = 8,
XFR_PARITYLESS_WRITE = 0x10,
XFR_NO_PARITY_STRIPE = 0x20, /* parity stripe is not available */
XFR_DATA_BLOCK = 0x40, /* data block in request */
XFR_PARITY_BLOCK = 0x80, /* parity block in request */
XFR_BAD_SUBDISK = 0x100, /* this subdisk is dead */
XFR_MALLOCED = 0x200, /* this buffer is malloced */
#if DEBUG
XFR_PHASE2 = 0x800, /* documentation only: 2nd phase write */
#endif
XFR_REVIVECONFLICT = 0x1000, /* possible conflict with a revive operation */
/* operations that need a parity block */
XFR_PARITYOP = (XFR_NORMAL_WRITE | XFR_RECOVERY_READ | XFR_DEGRADED_WRITE),
/* operations that use the group parameters */
XFR_GROUPOP = (XFR_DEGRADED_WRITE | XFR_RECOVERY_READ),
/* operations that that use the data parameters */
XFR_DATAOP = (XFR_NORMAL_READ | XFR_NORMAL_WRITE | XFR_PARITYLESS_WRITE),
/* operations requiring read before write */
XFR_RBW = (XFR_NORMAL_WRITE | XFR_DEGRADED_WRITE),
/* operations that need a malloced buffer */
XFR_NEEDS_MALLOC = (XFR_NORMAL_WRITE | XFR_RECOVERY_READ | XFR_DEGRADED_WRITE)
};
/* Describe one low-level request, part
* of a high-level request. This is an
* extended struct buf buffer, and the first
* element *must* be a struct buf. We pass this structure
* to the I/O routines instead of a struct buf in oder
* to be able to locate the high-level request when it
* completes.
*
* All offsets and lengths are in "blocks", i.e. sectors */
struct rqelement {
struct buf b; /* buf structure */
struct rqgroup *rqg; /* pointer to our group */
/* Information about the transfer */
daddr_t sdoffset; /* offset in subdisk */
int useroffset; /* offset in user buffer of normal data */
/* dataoffset and datalen refer to "individual"
* data transfers (normal read, parityless write)
* and also degraded write.
*
* groupoffset and grouplen refer to the other
* "group" operations (normal write, recovery read)
* Both the offsets are relative to the start of the
* local buffer */
int dataoffset; /* offset in buffer of the normal data */
int groupoffset; /* offset in buffer of group data */
short datalen; /* length of normal data (sectors) */
short grouplen; /* length of group data (sectors) */
short buflen; /* total buffer length to allocate */
short flags; /* really enum xferinfo (see above) */
/* Ways to find other components */
short sdno; /* subdisk number */
short driveno; /* drive number */
};
/* A group of requests built to satisfy a certain
* component of a user request */
struct rqgroup {
struct rqgroup *next; /* pointer to next group */
struct request *rq; /* pointer to the request */
short count; /* number of requests in this group */
short active; /* and number active */
short plexno; /* index of plex */
int badsdno; /* index of bad subdisk or -1 */
enum xferinfo flags; /* description of transfer */
struct rqelement rqe[0]; /* and the elements of this request */
};
/* Describe one high-level request and the
* work we have to do to satisfy it */
struct request {
struct buf *bp; /* pointer to the high-level request */
int flags;
union {
int volno; /* volume index */
int plexno; /* or plex index */
} volplex;
int error; /* current error indication */
short isplex; /* set if this is a plex request */
short active; /* number of subrequests still active */
struct rqgroup *rqg; /* pointer to the first group of requests */
struct rqgroup *lrqg; /* and to the first group of requests */
struct request *next; /* link of waiting requests */
};
/* Extended buffer header for subdisk I/O. Includes
* a pointer to the user I/O request. */
struct sdbuf {
struct buf b; /* our buffer */
struct buf *bp; /* and pointer to parent */
short driveno; /* drive index */
short sdno; /* and subdisk index */
};
/* Values returned by rqe and friends.
* Be careful with these: they are in order of increasing
* seriousness. Some routines check for > REQUEST_RECOVERED
* to indicate a completely failed request. */
enum requeststatus {
REQUEST_OK, /* request built OK */
REQUEST_RECOVERED, /* request OK, but involves RAID5 recovery */
REQUEST_EOF, /* request failed: outside plex */
REQUEST_DOWN, /* request failed: subdisk down */
REQUEST_ENOMEM /* ran out of memory */
};
