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Introduce simple random fault injection. It is currently controlled 

by setting RUMP_BLKFAIL to control the frequency and optionally
RUMP_BLKFAIL_SEED, which seeds the "random" number generator.  Feel
free to extend the code if you want something "a little more" for
your purposes.
This commit is contained in:
pooka 2009-02-10 20:43:01 +00:00
parent a9ecd753f2
commit fa73a97f70
1 changed files with 78 additions and 7 deletions
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85
sys/rump/librump/rumpvfs/rumpblk.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: rumpblk.c,v 1.2 2009/01/27 09:14:01 pooka Exp $ */
/* $NetBSD: rumpblk.c,v 1.3 2009/02/10 20:43:01 pooka Exp $ */
/*
* Copyright (c) 2009 Antti Kantee. All Rights Reserved.
@ -34,7 +34,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rumpblk.c,v 1.2 2009/01/27 09:14:01 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: rumpblk.c,v 1.3 2009/02/10 20:43:01 pooka Exp $");
#include <sys/param.h>
#include <sys/buf.h>
@ -66,6 +66,7 @@ dev_type_read(rumpblk_read);
dev_type_write(rumpblk_write);
dev_type_ioctl(rumpblk_ioctl);
dev_type_strategy(rumpblk_strategy);
dev_type_strategy(rumpblk_strategy_fail);
dev_type_dump(rumpblk_dump);
dev_type_size(rumpblk_size);
@ -74,20 +75,53 @@ static const struct bdevsw rumpblk_bdevsw = {
nodump, nosize, D_DISK
};
static const struct bdevsw rumpblk_bdevsw_fail = {
rumpblk_open, rumpblk_close, rumpblk_strategy_fail, rumpblk_ioctl,
nodump, nosize, D_DISK
};
static const struct cdevsw rumpblk_cdevsw = {
rumpblk_open, rumpblk_close, rumpblk_read, rumpblk_write,
rumpblk_ioctl, nostop, notty, nopoll, nommap, nokqfilter, D_DISK
};
/* XXX: not mpsafe */
/* fail every n out of BLKFAIL_MAX */
#define BLKFAIL_MAX 10000
static int blkfail;
static unsigned randstate;
int
rumpblk_init()
{
char buf[64];
int rumpblk = RUMPBLK;
int error;
return devsw_attach("rumpblk", &rumpblk_bdevsw, &rumpblk,
&rumpblk_cdevsw, &rumpblk);
if (rumpuser_getenv("RUMP_BLKFAIL", buf, sizeof(buf), &error) == 0) {
blkfail = strtoul(buf, NULL, 10);
/* fail everything */
if (blkfail > BLKFAIL_MAX)
blkfail = BLKFAIL_MAX;
if (rumpuser_getenv("RUMP_BLKFAIL_SEED", buf, sizeof(buf),
&error) == 0) {
randstate = strtoul(buf, NULL, 10);
} else {
randstate = arc4random(); /* XXX: not enough entropy */
}
printf("rumpblk: FAULT INJECTION ACTIVE! every %d out of"
" %d I/O will fail. key %u\n", blkfail, BLKFAIL_MAX,
randstate);
} else {
blkfail = 0;
}
if (blkfail) {
return devsw_attach("rumpblk", &rumpblk_bdevsw_fail, &rumpblk,
&rumpblk_cdevsw, &rumpblk);
} else {
return devsw_attach("rumpblk", &rumpblk_bdevsw, &rumpblk,
&rumpblk_cdevsw, &rumpblk);
}
}
int
@ -203,8 +237,8 @@ rumpblk_write(dev_t dev, struct uio *uio, int flags)
panic("%s: unimplemented", __func__);
}
void
rumpblk_strategy(struct buf *bp)
static void
dostrategy(struct buf *bp)
{
struct rblkdev *rblk = &minors[minor(bp->b_dev)];
off_t off;
@ -278,3 +312,40 @@ rumpblk_strategy(struct buf *bp)
}
}
}
void
rumpblk_strategy(struct buf *bp)
{
dostrategy(bp);
}
/*
* <mlelstv> pooka, rand()
* <mlelstv> [paste]
*/
static unsigned
gimmerand(void)
{
return (randstate = randstate * 1103515245 + 12345) % (0x80000000L);
}
/*
* Block device with very simple fault injection. Fails every
* n out of BLKFAIL_MAX I/O with EIO. n is determined by the env
* variable RUMP_BLKFAIL.
*/
void
rumpblk_strategy_fail(struct buf *bp)
{
if (gimmerand() % BLKFAIL_MAX >= blkfail) {
dostrategy(bp);
} else {
printf("block fault injection: failing I/O on block %lld\n",
(long long)bp->b_blkno);
bp->b_error = EIO;
biodone(bp);
}
}