mirror of
https://github.com/torvalds/linux.git
synced 2024-11-08 21:21:47 +00:00
a8e026c785
Rename raid6/raid6x86.h to raid6/x86.h and modify some comments. Signed-off-by: NeilBrown <neilb@suse.de>
133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* Copyright 2002 H. Peter Anvin - All Rights Reserved
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
|
|
* Boston MA 02111-1307, USA; either version 2 of the License, or
|
|
* (at your option) any later version; incorporated herein by reference.
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* raid6/recov.c
|
|
*
|
|
* RAID-6 data recovery in dual failure mode. In single failure mode,
|
|
* use the RAID-5 algorithm (or, in the case of Q failure, just reconstruct
|
|
* the syndrome.)
|
|
*/
|
|
|
|
#include <linux/raid/pq.h>
|
|
|
|
/* Recover two failed data blocks. */
|
|
void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
|
|
void **ptrs)
|
|
{
|
|
u8 *p, *q, *dp, *dq;
|
|
u8 px, qx, db;
|
|
const u8 *pbmul; /* P multiplier table for B data */
|
|
const u8 *qmul; /* Q multiplier table (for both) */
|
|
|
|
p = (u8 *)ptrs[disks-2];
|
|
q = (u8 *)ptrs[disks-1];
|
|
|
|
/* Compute syndrome with zero for the missing data pages
|
|
Use the dead data pages as temporary storage for
|
|
delta p and delta q */
|
|
dp = (u8 *)ptrs[faila];
|
|
ptrs[faila] = (void *)raid6_empty_zero_page;
|
|
ptrs[disks-2] = dp;
|
|
dq = (u8 *)ptrs[failb];
|
|
ptrs[failb] = (void *)raid6_empty_zero_page;
|
|
ptrs[disks-1] = dq;
|
|
|
|
raid6_call.gen_syndrome(disks, bytes, ptrs);
|
|
|
|
/* Restore pointer table */
|
|
ptrs[faila] = dp;
|
|
ptrs[failb] = dq;
|
|
ptrs[disks-2] = p;
|
|
ptrs[disks-1] = q;
|
|
|
|
/* Now, pick the proper data tables */
|
|
pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
|
|
qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];
|
|
|
|
/* Now do it... */
|
|
while ( bytes-- ) {
|
|
px = *p ^ *dp;
|
|
qx = qmul[*q ^ *dq];
|
|
*dq++ = db = pbmul[px] ^ qx; /* Reconstructed B */
|
|
*dp++ = db ^ px; /* Reconstructed A */
|
|
p++; q++;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(raid6_2data_recov);
|
|
|
|
/* Recover failure of one data block plus the P block */
|
|
void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs)
|
|
{
|
|
u8 *p, *q, *dq;
|
|
const u8 *qmul; /* Q multiplier table */
|
|
|
|
p = (u8 *)ptrs[disks-2];
|
|
q = (u8 *)ptrs[disks-1];
|
|
|
|
/* Compute syndrome with zero for the missing data page
|
|
Use the dead data page as temporary storage for delta q */
|
|
dq = (u8 *)ptrs[faila];
|
|
ptrs[faila] = (void *)raid6_empty_zero_page;
|
|
ptrs[disks-1] = dq;
|
|
|
|
raid6_call.gen_syndrome(disks, bytes, ptrs);
|
|
|
|
/* Restore pointer table */
|
|
ptrs[faila] = dq;
|
|
ptrs[disks-1] = q;
|
|
|
|
/* Now, pick the proper data tables */
|
|
qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];
|
|
|
|
/* Now do it... */
|
|
while ( bytes-- ) {
|
|
*p++ ^= *dq = qmul[*q ^ *dq];
|
|
q++; dq++;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(raid6_datap_recov);
|
|
|
|
#ifndef __KERNEL__
|
|
/* Testing only */
|
|
|
|
/* Recover two failed blocks. */
|
|
void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs)
|
|
{
|
|
if ( faila > failb ) {
|
|
int tmp = faila;
|
|
faila = failb;
|
|
failb = tmp;
|
|
}
|
|
|
|
if ( failb == disks-1 ) {
|
|
if ( faila == disks-2 ) {
|
|
/* P+Q failure. Just rebuild the syndrome. */
|
|
raid6_call.gen_syndrome(disks, bytes, ptrs);
|
|
} else {
|
|
/* data+Q failure. Reconstruct data from P,
|
|
then rebuild syndrome. */
|
|
/* NOT IMPLEMENTED - equivalent to RAID-5 */
|
|
}
|
|
} else {
|
|
if ( failb == disks-2 ) {
|
|
/* data+P failure. */
|
|
raid6_datap_recov(disks, bytes, faila, ptrs);
|
|
} else {
|
|
/* data+data failure. */
|
|
raid6_2data_recov(disks, bytes, faila, failb, ptrs);
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif
|