diff options
Diffstat (limited to 'lkm/vinum/request.h')
| -rw-r--r-- | lkm/vinum/request.h | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/lkm/vinum/request.h b/lkm/vinum/request.h new file mode 100644 index 0000000..b4beccc --- /dev/null +++ b/lkm/vinum/request.h @@ -0,0 +1,159 @@ +/*- + * 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 */ +}; |
