22db1e9ff5
redundant paths to the same device.
This class reacts to a label in the first sector of the device,
which is created the following way:
# "0123456789abcdef012345..."
# "<----magic-----><-id-...>
echo "GEOM::FOX someid" | dd of=/dev/da0 conv=sync
NB: Since the fact that multiple disk devices are in fact the same
device is not known to GEOM, the geom taste/spoil process cannot
fully catch all corner cases and this module can therefore be
confused if you do the right wrong things.
NB: The disk level drivers need to do the right thing for this to
be useful, and that is not by definition currently the case.
469 lines
11 KiB
C
469 lines
11 KiB
C
/*-
|
|
* Copyright (c) 2003 Poul-Henning Kamp
|
|
* All rights reserved.
|
|
*
|
|
* 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. The names of the authors may not be used to endorse or promote
|
|
* products derived from this software without specific prior written
|
|
* permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR 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.
|
|
*
|
|
* $FreeBSD$
|
|
*
|
|
* This is a GEOM module for handling path selection for multi-path
|
|
* storage devices. It is named "fox" because it, like they, prefer
|
|
* to have multiple exits to choose from.
|
|
*
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/conf.h>
|
|
#include <sys/bio.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/libkern.h>
|
|
#include <sys/endian.h>
|
|
#include <sys/md5.h>
|
|
#include <sys/errno.h>
|
|
#include <geom/geom.h>
|
|
|
|
#define FOX_CLASS_NAME "FOX"
|
|
#define FOX_MAGIC "GEOM::FOX"
|
|
|
|
struct g_fox_softc {
|
|
off_t mediasize;
|
|
u_int sectorsize;
|
|
TAILQ_HEAD(, bio) queue;
|
|
struct mtx lock;
|
|
u_char magic[16];
|
|
struct g_consumer *path;
|
|
struct g_consumer *opath;
|
|
int waiting;
|
|
int cr, cw, ce;
|
|
};
|
|
|
|
/*
|
|
* This function is called whenever we need to select a new path.
|
|
*/
|
|
static void
|
|
g_fox_select_path(void *arg, int flag)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_fox_softc *sc;
|
|
struct g_consumer *cp1;
|
|
struct bio *bp;
|
|
int error;
|
|
|
|
g_topology_assert();
|
|
if (flag == EV_CANCEL)
|
|
return;
|
|
gp = arg;
|
|
sc = gp->softc;
|
|
|
|
if (sc->opath != NULL) {
|
|
/*
|
|
* First, close the old path entirely.
|
|
*/
|
|
printf("Closing old path (%s) on fox (%s)\n",
|
|
sc->opath->provider->name, gp->name);
|
|
|
|
cp1 = LIST_NEXT(sc->opath, consumer);
|
|
|
|
error = g_access_rel(sc->opath, -sc->cr, -sc->cw, -(sc->ce + 1));
|
|
KASSERT(error == 0, ("Failed close of old path %d", error));
|
|
|
|
/*
|
|
* The attempt to reopen it with a exclusive count
|
|
*/
|
|
error = g_access_rel(sc->opath, 0, 0, 1);
|
|
if (error) {
|
|
/*
|
|
* Ok, ditch this consumer, we can't use it.
|
|
*/
|
|
printf("Drop old path (%s) on fox (%s)\n",
|
|
sc->opath->provider->name, gp->name);
|
|
g_detach(sc->opath);
|
|
g_destroy_consumer(sc->opath);
|
|
if (LIST_EMPTY(&gp->consumer)) {
|
|
/* No consumers left */
|
|
g_wither_geom(gp, ENXIO);
|
|
for (;;) {
|
|
bp = TAILQ_FIRST(&sc->queue);
|
|
if (bp == NULL)
|
|
break;
|
|
TAILQ_REMOVE(&sc->queue, bp, bio_queue);
|
|
bp->bio_error = ENXIO;
|
|
g_std_done(bp);
|
|
}
|
|
return;
|
|
}
|
|
} else {
|
|
printf("Got e-bit on old path (%s) on fox (%s)\n",
|
|
sc->opath->provider->name, gp->name);
|
|
}
|
|
sc->opath = NULL;
|
|
} else {
|
|
cp1 = LIST_FIRST(&gp->consumer);
|
|
}
|
|
if (cp1 == NULL)
|
|
cp1 = LIST_FIRST(&gp->consumer);
|
|
printf("Open new path (%s) on fox (%s)\n",
|
|
cp1->provider->name, gp->name);
|
|
error = g_access_rel(cp1, sc->cr, sc->cw, sc->ce);
|
|
if (error) {
|
|
/*
|
|
* If we failed, we take another trip through here
|
|
*/
|
|
printf("Open new path (%s) on fox (%s) failed, reselect.\n",
|
|
cp1->provider->name, gp->name);
|
|
sc->opath = cp1;
|
|
g_post_event(g_fox_select_path, gp, M_WAITOK, gp, NULL);
|
|
} else {
|
|
printf("Open new path (%s) on fox (%s) succeeded\n",
|
|
cp1->provider->name, gp->name);
|
|
mtx_lock(&sc->lock);
|
|
sc->path = cp1;
|
|
sc->waiting = 0;
|
|
for (;;) {
|
|
bp = TAILQ_FIRST(&sc->queue);
|
|
if (bp == NULL)
|
|
break;
|
|
TAILQ_REMOVE(&sc->queue, bp, bio_queue);
|
|
g_io_request(bp, sc->path);
|
|
}
|
|
mtx_unlock(&sc->lock);
|
|
}
|
|
}
|
|
|
|
static void
|
|
g_fox_orphan(struct g_consumer *cp)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_fox_softc *sc;
|
|
int error, mark;
|
|
|
|
g_topology_assert();
|
|
gp = cp->geom;
|
|
sc = gp->softc;
|
|
printf("Removing path (%s) from fox (%s)\n",
|
|
cp->provider->name, gp->name);
|
|
mtx_lock(&sc->lock);
|
|
if (cp == sc->path) {
|
|
sc->opath = NULL;
|
|
sc->path = NULL;
|
|
sc->waiting = 1;
|
|
mark = 1;
|
|
} else {
|
|
mark = 0;
|
|
}
|
|
mtx_unlock(&sc->lock);
|
|
|
|
g_access_rel(cp, -cp->acr, -cp->acw, -cp->ace);
|
|
error = cp->provider->error;
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
if (!LIST_EMPTY(&gp->consumer)) {
|
|
if (mark)
|
|
g_post_event(g_fox_select_path, gp, M_WAITOK, gp, NULL);
|
|
return;
|
|
}
|
|
|
|
mtx_destroy(&sc->lock);
|
|
gp->softc = NULL;
|
|
g_free(gp->softc);
|
|
g_wither_geom(gp, ENXIO);
|
|
}
|
|
|
|
static void
|
|
g_fox_done(struct bio *bp)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_fox_softc *sc;
|
|
int error;
|
|
|
|
if (bp->bio_error == 0) {
|
|
g_std_done(bp);
|
|
return;
|
|
}
|
|
gp = bp->bio_from->geom;
|
|
sc = gp->softc;
|
|
if (bp->bio_from != sc->path) {
|
|
g_io_request(bp, sc->path);
|
|
return;
|
|
}
|
|
mtx_lock(&sc->lock);
|
|
sc->opath = sc->path;
|
|
sc->path = NULL;
|
|
error = g_post_event(g_fox_select_path, gp, M_NOWAIT, gp, NULL);
|
|
if (error) {
|
|
bp->bio_error = ENOMEM;
|
|
g_std_done(bp);
|
|
} else {
|
|
sc->waiting = 1;
|
|
TAILQ_INSERT_TAIL(&sc->queue, bp, bio_queue);
|
|
}
|
|
mtx_unlock(&sc->lock);
|
|
}
|
|
|
|
static void
|
|
g_fox_start(struct bio *bp)
|
|
{
|
|
struct g_geom *gp;
|
|
struct bio *bp2;
|
|
struct g_fox_softc *sc;
|
|
int error;
|
|
|
|
gp = bp->bio_to->geom;
|
|
sc = gp->softc;
|
|
if (sc == NULL) {
|
|
g_io_deliver(bp, ENXIO);
|
|
return;
|
|
}
|
|
switch(bp->bio_cmd) {
|
|
case BIO_READ:
|
|
case BIO_WRITE:
|
|
case BIO_DELETE:
|
|
bp2 = g_clone_bio(bp);
|
|
if (bp2 == NULL) {
|
|
g_io_deliver(bp, ENOMEM);
|
|
break;
|
|
}
|
|
bp2->bio_offset += sc->sectorsize;
|
|
bp2->bio_done = g_fox_done;
|
|
mtx_lock(&sc->lock);
|
|
if (sc->path == NULL || !TAILQ_EMPTY(&sc->queue)) {
|
|
if (sc->waiting == 0) {
|
|
error = g_post_event(g_fox_select_path, gp,
|
|
M_NOWAIT, gp, NULL);
|
|
if (error) {
|
|
g_destroy_bio(bp2);
|
|
bp2 = NULL;
|
|
g_io_deliver(bp, error);
|
|
} else {
|
|
sc->waiting = 1;
|
|
}
|
|
}
|
|
if (bp2 != NULL)
|
|
TAILQ_INSERT_TAIL(&sc->queue, bp2,
|
|
bio_queue);
|
|
} else {
|
|
g_io_request(bp2, sc->path);
|
|
}
|
|
mtx_unlock(&sc->lock);
|
|
break;
|
|
default:
|
|
g_io_deliver(bp, EOPNOTSUPP);
|
|
break;
|
|
}
|
|
return;
|
|
}
|
|
|
|
static int
|
|
g_fox_access(struct g_provider *pp, int dr, int dw, int de)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_fox_softc *sc;
|
|
struct g_consumer *cp1;
|
|
int error;
|
|
|
|
g_topology_assert();
|
|
gp = pp->geom;
|
|
sc = gp->softc;
|
|
if (sc == NULL)
|
|
return (ENXIO);
|
|
|
|
if (sc->cr == 0 && sc->cw == 0 && sc->ce == 0) {
|
|
/*
|
|
* First open, open all consumers with an exclusive bit
|
|
*/
|
|
error = 0;
|
|
LIST_FOREACH(cp1, &gp->consumer, consumer) {
|
|
error = g_access_rel(cp1, 0, 0, 1);
|
|
if (error) {
|
|
printf("FOX: access(%s,0,0,1) = %d\n",
|
|
cp1->provider->name, error);
|
|
break;
|
|
}
|
|
}
|
|
if (error) {
|
|
LIST_FOREACH(cp1, &gp->consumer, consumer) {
|
|
if (cp1->ace)
|
|
g_access_rel(cp1, 0, 0, -1);
|
|
}
|
|
return (error);
|
|
}
|
|
}
|
|
if (sc->path == NULL)
|
|
g_fox_select_path(gp, 0);
|
|
if (sc->path == NULL)
|
|
error = ENXIO;
|
|
else
|
|
error = g_access_rel(sc->path, dr, dw, de);
|
|
if (error == 0) {
|
|
sc->cr += dr;
|
|
sc->cw += dw;
|
|
sc->ce += de;
|
|
if (sc->cr == 0 && sc->cw == 0 && sc->ce == 0) {
|
|
/*
|
|
* Last close, remove e-bit on all consumers
|
|
*/
|
|
LIST_FOREACH(cp1, &gp->consumer, consumer)
|
|
g_access_rel(cp1, 0, 0, -1);
|
|
}
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
static struct g_geom *
|
|
g_fox_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
|
|
{
|
|
struct g_geom *gp, *gp2;
|
|
struct g_provider *pp2;
|
|
struct g_consumer *cp, *cp2;
|
|
struct g_fox_softc *sc, *sc2;
|
|
int error;
|
|
u_int sectorsize;
|
|
u_char *buf;
|
|
|
|
g_trace(G_T_TOPOLOGY, "fox_taste(%s, %s)", mp->name, pp->name);
|
|
g_topology_assert();
|
|
if (!strcmp(pp->geom->class->name, mp->name))
|
|
return (NULL);
|
|
gp = g_new_geomf(mp, "%s.fox", pp->name);
|
|
gp->softc = g_malloc(sizeof(struct g_fox_softc), M_WAITOK | M_ZERO);
|
|
sc = gp->softc;
|
|
|
|
gp->start = g_fox_start;
|
|
gp->spoiled = g_fox_orphan;
|
|
gp->orphan = g_fox_orphan;
|
|
gp->access= g_fox_access;
|
|
cp = g_new_consumer(gp);
|
|
g_attach(cp, pp);
|
|
error = g_access_rel(cp, 1, 0, 0);
|
|
if (error) {
|
|
g_free(sc);
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
g_destroy_geom(gp);
|
|
return(NULL);
|
|
}
|
|
do {
|
|
sectorsize = cp->provider->sectorsize;
|
|
g_topology_unlock();
|
|
buf = g_read_data(cp, 0, sectorsize, &error);
|
|
g_topology_lock();
|
|
if (buf == NULL || error != 0)
|
|
break;
|
|
if (memcmp(buf, FOX_MAGIC, strlen(FOX_MAGIC)))
|
|
break;
|
|
|
|
/*
|
|
* First we need to see if this a new path for an existing fox.
|
|
*/
|
|
LIST_FOREACH(gp2, &mp->geom, geom) {
|
|
sc2 = gp2->softc;
|
|
if (sc == NULL)
|
|
continue;
|
|
if (memcmp(buf + 16, sc2->magic, sizeof sc2->magic))
|
|
continue;
|
|
break;
|
|
}
|
|
if (gp2 != NULL) {
|
|
/*
|
|
* It was. Create a new consumer for that fox,
|
|
* attach it, and if the fox is open, open this
|
|
* path with an exclusive count of one.
|
|
*/
|
|
printf("Adding path (%s) to fox (%s)\n",
|
|
pp->name, gp2->name);
|
|
cp2 = g_new_consumer(gp2);
|
|
g_attach(cp2, pp);
|
|
pp2 = LIST_FIRST(&gp2->provider);
|
|
if (pp2->acr > 0 || pp2->acw > 0 || pp2->ace > 0) {
|
|
error = g_access_rel(cp2, 0, 0, 1);
|
|
if (error) {
|
|
/*
|
|
* This is bad, or more likely,
|
|
* the user is doing something stupid
|
|
*/
|
|
printf(
|
|
"WARNING: New path (%s) to fox(%s) not added: %s\n%s",
|
|
cp->provider->name, gp2->name,
|
|
"Could not get exclusive bit.",
|
|
"WARNING: This indicates a risk of data inconsistency."
|
|
);
|
|
g_detach(cp2);
|
|
g_destroy_consumer(cp2);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
printf("Creating new fox (%s)\n", pp->name);
|
|
sc->path = cp;
|
|
memcpy(sc->magic, buf + 16, sizeof sc->magic);
|
|
pp2 = g_new_providerf(gp, "%s", gp->name);
|
|
pp2->mediasize = sc->mediasize = pp->mediasize - pp->sectorsize;
|
|
pp2->sectorsize = sc->sectorsize = pp->sectorsize;
|
|
printf("fox %s lock %p\n", gp->name, &sc->lock);
|
|
|
|
mtx_init(&sc->lock, "fox queue", NULL, MTX_DEF);
|
|
TAILQ_INIT(&sc->queue);
|
|
g_error_provider(pp2, 0);
|
|
} while (0);
|
|
if (buf != NULL)
|
|
g_free(buf);
|
|
g_access_rel(cp, -1, 0, 0);
|
|
|
|
if (!LIST_EMPTY(&gp->provider))
|
|
return (gp);
|
|
|
|
g_free(gp->softc);
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
g_destroy_geom(gp);
|
|
return (NULL);
|
|
}
|
|
|
|
static int
|
|
g_fox_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
|
|
{
|
|
struct g_fox_softc *sc;
|
|
|
|
g_topology_assert();
|
|
sc = gp->softc;
|
|
gp->softc = NULL;
|
|
mtx_destroy(&sc->lock);
|
|
g_free(gp->softc);
|
|
g_wither_geom(gp, ENXIO);
|
|
return (0);
|
|
}
|
|
|
|
static struct g_class g_fox_class = {
|
|
.name = FOX_CLASS_NAME,
|
|
.taste = g_fox_taste,
|
|
.destroy_geom = g_fox_destroy_geom,
|
|
};
|
|
|
|
DECLARE_GEOM_CLASS(g_fox_class, g_fox);
|