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First cut at GEOM based multipath. This is an active/passive{/passive...}

Browse Source 
arrangement that has no intrinsic internal knowledge of whether devices
it is given are truly multipath devices. As such, this is a simplistic
approach, but still a useful one.

The basic approach is to (at present- this will change soon) use camcontrol
to find likely identical devices and and label the trailing sector of the
first one. This label contains both a full UUID and a name. The name is
what is presented in /dev/multipath, but the UUID is used as a true
distinguishor at g_taste time, thus making sure we don't have chaos
on a shared SAN where everyone names their data multipath as "Fred".

The first of N identical devices (and N *may* be 1!) becomes the active
path until a BIO request is failed with EIO or ENXIO. When this occurs,
the active disk is ripped away and the next in a list is picked to
(retry and) continue with.

During g_taste events new disks that meet the match criteria for existing
multipath geoms get added to the tail end of the list.

Thus, this active/passive setup actually does work for devices which
go away and come back, as do (now) mpt(4) and isp(4) SAN based disks.

There is still a lot to do to improve this- like about 5 of the 12
recommendations I've received about it,  but it's been functional enough
for a while that it deserves a broader test base.

Reviewed by: pjd
Sponsored by: IronPort Systems
MFC: 2 months
This commit is contained in:
Matt Jacob 2007-02-27 04:01:58 +00:00
parent 5af924bf6c
commit e770bc6bf5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=167050
10 changed files with 1121 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
etc/mtree/BSD.include.dist
View File

@ -114,6 +114,8 @@
..
mirror
..
multipath
..
nop
..
raid3

1
sbin/geom/class/Makefile
View File

@ -10,6 +10,7 @@ SUBDIR+=eli
SUBDIR+=journal
SUBDIR+=label
SUBDIR+=mirror
SUBDIR+=multipath
SUBDIR+=nop
SUBDIR+=raid3
SUBDIR+=shsec

10
sbin/geom/class/multipath/Makefile Normal file
View File

@ -0,0 +1,10 @@
# $FreeBSD$
.PATH: ${.CURDIR}/../../misc
CLASS= multipath
NO_MAN=true
.include <bsd.lib.mk>
CFLAGS+= -I${.CURDIR}/../../../../sys

230
sbin/geom/class/multipath/geom_multipath.c Normal file
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@ -0,0 +1,230 @@
/*-
* Copyright (c) 2006 Mathew Jacob <mjacob@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <errno.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <assert.h>
#include <libgeom.h>
#include <uuid.h>
#include <geom/multipath/g_multipath.h>
#include "core/geom.h"
#include "misc/subr.h"
uint32_t lib_version = G_LIB_VERSION;
uint32_t version = G_MULTIPATH_VERSION;
static void mp_main(struct gctl_req *, unsigned int);
static void mp_label(struct gctl_req *);
static void mp_clear(struct gctl_req *);
struct g_command class_commands[] = {
{
"label", G_FLAG_VERBOSE | G_FLAG_LOADKLD, mp_main, G_NULL_OPTS,
"[-v] name prov ..."
},
{
"clear", G_FLAG_VERBOSE, mp_main, G_NULL_OPTS,
"[-v] prov ..."
},
G_CMD_SENTINEL
};
static void
mp_main(struct gctl_req *req, unsigned int flags __unused)
{
const char *name;
name = gctl_get_ascii(req, "verb");
if (name == NULL) {
gctl_error(req, "No '%s' argument.", "verb");
return;
}
if (strcmp(name, "label") == 0) {
mp_label(req);
} else if (strcmp(name, "clear") == 0) {
mp_clear(req);
} else {
gctl_error(req, "Unknown command: %s.", name);
}
}
static void
mp_label(struct gctl_req *req)
{
struct g_multipath_metadata md;
off_t disksiz = 0, msize;
uint8_t *sector;
char *ptr;
uuid_t uuid;
uint32_t secsize = 0, ssize, status;
const char *name;
int error, i, nargs;
nargs = gctl_get_int(req, "nargs");
if (nargs < 2) {
gctl_error(req, "wrong number of arguments.");
return;
}
/*
* First, check each provider to make sure it's the same size.
* This also gets us our size and sectorsize for the metadata.
*/
for (i = 1; i < nargs; i++) {
name = gctl_get_ascii(req, "arg%d", i);
msize = g_get_mediasize(name);
ssize = g_get_sectorsize(name);
if (msize == 0 || ssize == 0) {
gctl_error(req, "cannot get information about %s: %s.",
name, strerror(errno));
return;
}
if (i == 1) {
secsize = ssize;
disksiz = msize;
} else {
if (secsize != ssize) {
gctl_error(req, "%s sector size %u different.",
name, ssize);
return;
}
if (disksiz != msize) {
gctl_error(req, "%s media size %ju different.",
name, (intmax_t)msize);
return;
}
}
}
/*
* Allocate a sector to write as metadata.
*/
sector = malloc(secsize);
if (sector == NULL) {
gctl_error(req, "unable to allocate metadata buffer");
return;
}
memset(sector, 0, secsize);
/*
* Generate metadata.
*/
strlcpy(md.md_magic, G_MULTIPATH_MAGIC, sizeof(md.md_magic));
md.md_version = G_MULTIPATH_VERSION;
name = gctl_get_ascii(req, "arg0");
strlcpy(md.md_name, name, sizeof(md.md_name));
md.md_size = disksiz;
md.md_sectorsize = secsize;
uuid_create(&uuid, &status);
if (status != uuid_s_ok) {
gctl_error(req, "cannot create a UUID.");
return;
}
uuid_to_string(&uuid, &ptr, &status);
if (status != uuid_s_ok) {
gctl_error(req, "cannot stringify a UUID.");
return;
}
strlcpy(md.md_uuid, ptr, sizeof (md.md_uuid));
free(ptr);
/*
* Clear last sector first for each provider to spoil anything extant
*/
for (i = 1; i < nargs; i++) {
name = gctl_get_ascii(req, "arg%d", i);
error = g_metadata_clear(name, NULL);
if (error != 0) {
gctl_error(req, "cannot clear metadata on %s: %s.",
name, strerror(error));
return;
}
}
multipath_metadata_encode(&md, sector);
/*
* Ok, store metadata.
*/
for (i = 1; i < nargs; i++) {
name = gctl_get_ascii(req, "arg%d", i);
error = g_metadata_store(name, sector, secsize);
if (error != 0) {
fprintf(stderr, "Can't store metadata on %s: %s.\n",
name, strerror(error));
goto fail;
}
}
return;
fail:
/*
* Clear last sector first for each provider to spoil anything extant
*/
for (i = 1; i < nargs; i++) {
name = gctl_get_ascii(req, "arg%d", i);
error = g_metadata_clear(name, NULL);
if (error != 0) {
gctl_error(req, "cannot clear metadata on %s: %s.",
name, strerror(error));
continue;
}
}
}
static void
mp_clear(struct gctl_req *req)
{
const char *name;
int error, i, nargs;
nargs = gctl_get_int(req, "nargs");
if (nargs < 1) {
gctl_error(req, "Too few arguments.");
return;
}
for (i = 0; i < nargs; i++) {
name = gctl_get_ascii(req, "arg%d", i);
error = g_metadata_clear(name, G_MULTIPATH_MAGIC);
if (error != 0) {
fprintf(stderr, "Can't clear metadata on %s: %s.\n",
name, strerror(error));
gctl_error(req, "Not fully done.");
continue;
}
}
}

1
sys/conf/NOTES
View File

@ -147,6 +147,7 @@ options GEOM_JOURNAL # Journaling.
options GEOM_LABEL # Providers labelization.
options GEOM_MBR # DOS/MBR partitioning
options GEOM_MIRROR # Disk mirroring.
options GEOM_MULTIPATH # Disk multipath
options GEOM_NOP # Test class.
options GEOM_PART_APM # Apple partitioning
options GEOM_PART_GPT # GPT partitioning

1
sys/conf/files
View File

@ -1210,6 +1210,7 @@ geom/label/g_label_reiserfs.c optional geom_label
geom/label/g_label_ufs.c optional geom_label
geom/mirror/g_mirror.c optional geom_mirror
geom/mirror/g_mirror_ctl.c optional geom_mirror
geom/multipath/g_multipath.c optional geom_multipath
geom/nop/g_nop.c optional geom_nop
geom/part/g_part.c standard
geom/part/g_part_if.m standard

768
sys/geom/multipath/g_multipath.c Normal file
View File

@ -0,0 +1,768 @@
/*-
* Copyright (c) 2006-2007 Matthew Jacob <mjacob@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
*/
/*
* Based upon work by Pawel Jakub Dawidek <pjd@FreeBSD.org> for all of the
* fine geom examples, and by Poul Henning Kamp <phk@FreeBSD.org> for GEOM
* itself, all of which is most gratefully acknowledged.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/bio.h>
#include <sys/sysctl.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <geom/geom.h>
#include <geom/multipath/g_multipath.h>
SYSCTL_DECL(_kern_geom);
SYSCTL_NODE(_kern_geom, OID_AUTO, multipath, CTLFLAG_RW, 0,
"GEOM_MULTIPATH tunables");
static u_int g_multipath_debug = 0;
SYSCTL_UINT(_kern_geom_multipath, OID_AUTO, debug, CTLFLAG_RW,
&g_multipath_debug, 0, "Debug level");
static enum {
GKT_NIL,
GKT_RUN,
GKT_DIE
} g_multipath_kt_state;
static struct bio_queue_head gmtbq;
static struct mtx gmtbq_mtx;
static void g_multipath_orphan(struct g_consumer *);
static void g_multipath_start(struct bio *);
static void g_multipath_done(struct bio *);
static void g_multipath_done_error(struct bio *);
static void g_multipath_kt(void *);
static int g_multipath_destroy(struct g_geom *);
static int
g_multipath_destroy_geom(struct gctl_req *, struct g_class *, struct g_geom *);
static g_taste_t g_multipath_taste;
static g_ctl_req_t g_multipath_config;
static g_init_t g_multipath_init;
static g_fini_t g_multipath_fini;
struct g_class g_multipath_class = {
.name = G_MULTIPATH_CLASS_NAME,
.version = G_VERSION,
.ctlreq = g_multipath_config,
.taste = g_multipath_taste,
.destroy_geom = g_multipath_destroy_geom,
.init = g_multipath_init,
.fini = g_multipath_fini
};
#define MP_BAD 0x1
#define MP_POSTED 0x2
static void
g_mpd(void *arg, int flags __unused)
{
struct g_consumer *cp;
g_topology_assert();
cp = arg;
if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0) {
g_access(cp, -cp->acr, -cp->acw, -cp->ace);
}
if (cp->provider) {
printf("GEOM_MULTIPATH: %s removed from %s\n",
cp->provider->name, cp->geom->name);
g_detach(cp);
}
g_destroy_consumer(cp);
}
static void
g_multipath_orphan(struct g_consumer *cp)
{
if ((cp->index & MP_POSTED) == 0) {
cp->index |= MP_POSTED;
printf("GEOM_MULTIPATH: %s orphaned in %s\n",
cp->provider->name, cp->geom->name);
g_mpd(cp, 0);
}
}
static void
g_multipath_start(struct bio *bp)
{
struct g_multipath_softc *sc;
struct g_geom *gp;
struct g_consumer *cp;
struct bio *cbp;
gp = bp->bio_to->geom;
sc = gp->softc;
KASSERT(sc != NULL, ("NULL sc"));
cp = sc->cp_active;
if (cp == NULL) {
g_io_deliver(bp, ENXIO);
return;
}
cbp = g_clone_bio(bp);
if (cbp == NULL) {
g_io_deliver(bp, ENOMEM);
return;
}
cbp->bio_done = g_multipath_done;
g_io_request(cbp, cp);
}
static void
g_multipath_done(struct bio *bp)
{
if (bp->bio_error == ENXIO || bp->bio_error == EIO) {
mtx_lock(&gmtbq_mtx);
bioq_insert_tail(&gmtbq, bp);
wakeup(&g_multipath_kt_state);
mtx_unlock(&gmtbq_mtx);
} else {
g_std_done(bp);
}
}
static void
g_multipath_done_error(struct bio *bp)
{
struct bio *pbp;
struct g_geom *gp;
struct g_multipath_softc *sc;
struct g_consumer *cp;
struct g_provider *pp;
/*
* If we had a failure, we have to check first to see
* whether the consumer it failed on was the currently
* active consumer (i.e., this is the first in perhaps
* a number of failures). If so, we then switch consumers
* to the next available consumer.
*/
g_topology_lock();
pbp = bp->bio_parent;
gp = pbp->bio_to->geom;
sc = gp->softc;
cp = bp->bio_from;
pp = cp->provider;
cp->index |= MP_BAD;
if (cp->nend == cp->nstart && pp->nend == pp->nstart) {
cp->index |= MP_POSTED;
g_post_event(g_mpd, cp, M_NOWAIT, NULL);
}
if (cp == sc->cp_active) {
struct g_consumer *lcp;
printf("GEOM_MULTIPATH: %s failed in %s\n",
pp->name, sc->sc_name);
sc->cp_active = NULL;
LIST_FOREACH(lcp, &gp->consumer, consumer) {
if ((lcp->index & MP_BAD) == 0) {
sc->cp_active = lcp;
break;
}
}
if (sc->cp_active == NULL) {
printf("GEOM_MULTIPATH: out of providers for %s\n",
sc->sc_name);
return;
} else {
printf("GEOM_MULTIPATH: %s now active path in %s\n",
sc->cp_active->provider->name, sc->sc_name);
}
}
g_topology_unlock();
/*
* If we can fruitfully restart the I/O, do so.
*/
if (sc->cp_active) {
g_destroy_bio(bp);
pbp->bio_children--;
g_multipath_start(pbp);
} else {
g_std_done(bp);
}
}
static void
g_multipath_kt(void *arg)
{
g_multipath_kt_state = GKT_RUN;
mtx_lock(&gmtbq_mtx);
while (g_multipath_kt_state == GKT_RUN) {
for (;;) {
struct bio *bp;
bp = bioq_takefirst(&gmtbq);
if (bp == NULL) {
break;
}
mtx_unlock(&gmtbq_mtx);
g_multipath_done_error(bp);
mtx_lock(&gmtbq_mtx);
}
msleep(&g_multipath_kt_state, &gmtbq_mtx, PRIBIO,
"gkt:wait", hz / 10);
}
mtx_unlock(&gmtbq_mtx);
wakeup(&g_multipath_kt_state);
kthread_exit(0);
}
static int
g_multipath_access(struct g_provider *pp, int dr, int dw, int de)
{
struct g_geom *gp;
struct g_consumer *cp, *badcp = NULL;
int error;
gp = pp->geom;
LIST_FOREACH(cp, &gp->consumer, consumer) {
error = g_access(cp, dr, dw, de);
if (error) {
badcp = cp;
goto fail;
}
}
return (0);
fail:
LIST_FOREACH(cp, &gp->consumer, consumer) {
if (cp == badcp) {
break;
}
(void) g_access(cp, -dr, -dw, -de);
}
return (error);
}
static struct g_geom *
g_multipath_create(struct g_class *mp, struct g_multipath_metadata *md)
{
struct g_multipath_softc *sc;
struct g_geom *gp;
struct g_provider *pp;
g_topology_assert();
LIST_FOREACH(gp, &mp->geom, geom) {
if (strcmp(gp->name, md->md_name) == 0) {
printf("GEOM_MULTIPATH: name %s already exists\n",
md->md_name);
return (NULL);
}
}
gp = g_new_geomf(mp, md->md_name);
if (gp == NULL) {
goto fail;
}
sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
if (sc == NULL) {
goto fail;
}
gp->softc = sc;
gp->start = g_multipath_start;
gp->orphan = g_multipath_orphan;
gp->access = g_multipath_access;
memcpy(sc->sc_uuid, md->md_uuid, sizeof (sc->sc_uuid));
memcpy(sc->sc_name, md->md_name, sizeof (sc->sc_name));
pp = g_new_providerf(gp, "multipath/%s", md->md_name);
if (pp == NULL) {
goto fail;
}
/* limit the provider to not have it stomp on metadata */
pp->mediasize = md->md_size - md->md_sectorsize;
pp->sectorsize = md->md_sectorsize;
sc->pp = pp;
g_error_provider(pp, 0);
return (gp);
fail:
if (gp != NULL) {
if (gp->softc != NULL) {
g_free(gp->softc);
}
g_destroy_geom(gp);
}
return (NULL);
}
static int
g_multipath_add_disk(struct g_geom *gp, struct g_provider *pp)
{
struct g_multipath_softc *sc;
struct g_consumer *cp, *nxtcp;
int error;
g_topology_assert();
sc = gp->softc;
KASSERT(sc, ("no softc"));
/*
* Make sure that the passed provider isn't already attached
*/
LIST_FOREACH(cp, &gp->consumer, consumer) {
if (cp->provider == pp) {
break;
}
}
if (cp) {
printf("GEOM_MULTIPATH: provider %s already attached to %s\n",
pp->name, gp->name);
return (EEXIST);
}
nxtcp = LIST_FIRST(&gp->consumer);
cp = g_new_consumer(gp);
if (cp == NULL) {
return (ENOMEM);
}
error = g_attach(cp, pp);
if (error != 0) {
printf("GEOM_MULTIPATH: cannot attach %s to %s",
pp->name, sc->sc_name);
g_destroy_consumer(cp);
return (error);
}
cp->private = sc;
cp->index = 0;
/*
* Set access permissions on new consumer to match other consumers
*/
if (nxtcp && (nxtcp->acr + nxtcp->acw + nxtcp->ace)) {
error = g_access(cp, nxtcp->acr, nxtcp->acw, nxtcp->ace);
if (error) {
printf("GEOM_MULTIPATH: cannot set access in "
"attaching %s to %s/%s (%d)\n",
pp->name, sc->sc_name, sc->sc_uuid, error);
g_detach(cp);
g_destroy_consumer(cp);
return (error);
}
}
printf("GEOM_MULTIPATH: adding %s to %s/%s\n",
pp->name, sc->sc_name, sc->sc_uuid);
if (sc->cp_active == NULL) {
sc->cp_active = cp;
printf("GEOM_MULTIPATH: %s now active path in %s\n",
pp->name, sc->sc_name);
}
return (0);
}
static int
g_multipath_destroy(struct g_geom *gp)
{
struct g_provider *pp;
g_topology_assert();
if (gp->softc == NULL) {
return (ENXIO);
}
pp = LIST_FIRST(&gp->provider);
if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
return (EBUSY);
}
printf("GEOM_MULTIPATH: destroying %s\n", gp->name);
g_free(gp->softc);
gp->softc = NULL;
g_wither_geom(gp, ENXIO);
return (0);
}
static int
g_multipath_destroy_geom(struct gctl_req *req, struct g_class *mp,
struct g_geom *gp)
{
return (g_multipath_destroy(gp));
}
static void
g_multipath_init(struct g_class *mp)
{
bioq_init(&gmtbq);
mtx_init(&gmtbq_mtx, "gmtbq", NULL, MTX_DEF);
if (kthread_create(g_multipath_kt, mp, NULL, 0, 0, "g_mp_kt") == 0) {
g_multipath_kt_state = GKT_RUN;
}
}
static void
g_multipath_fini(struct g_class *mp)
{
if (g_multipath_kt_state == GKT_RUN) {
mtx_lock(&gmtbq_mtx);
g_multipath_kt_state = GKT_DIE;
wakeup(&g_multipath_kt_state);
msleep(&g_multipath_kt_state, &gmtbq_mtx, PRIBIO,
"gmp:fini", 0);
mtx_unlock(&gmtbq_mtx);
}
}
static int
g_multipath_read_metadata(struct g_consumer *cp,
struct g_multipath_metadata *md)
{
struct g_provider *pp;
u_char *buf;
int error;
g_topology_assert();
error = g_access(cp, 1, 0, 0);
if (error != 0) {
return (error);
}
pp = cp->provider;
g_topology_unlock();
buf = g_read_data(cp, pp->mediasize - pp->sectorsize,
pp->sectorsize, &error);
g_topology_lock();
g_access(cp, -1, 0, 0);
if (buf == NULL) {
return (error);
}
multipath_metadata_decode(buf, md);
g_free(buf);
return (0);
}
static struct g_geom *
g_multipath_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
{
struct g_multipath_metadata md;
struct g_multipath_softc *sc;
struct g_consumer *cp;
struct g_geom *gp, *gp1;
int error, isnew;
g_topology_assert();
gp = g_new_geomf(mp, "multipath:taste");
gp->start = g_multipath_start;
gp->access = g_multipath_access;
gp->orphan = g_multipath_orphan;
cp = g_new_consumer(gp);
g_attach(cp, pp);
error = g_multipath_read_metadata(cp, &md);
g_detach(cp);
g_destroy_consumer(cp);
g_destroy_geom(gp);
if (error != 0) {
return (NULL);
}
gp = NULL;
if (strcmp(md.md_magic, G_MULTIPATH_MAGIC) != 0) {
if (g_multipath_debug) {
printf("%s is not MULTIPATH\n", pp->name);
}
return (NULL);
}
if (md.md_version != G_MULTIPATH_VERSION) {
printf("%s has version %d multipath id- this module is version "
" %d: rejecting\n", pp->name, md.md_version,
G_MULTIPATH_VERSION);
return (NULL);
}
if (g_multipath_debug) {
printf("MULTIPATH: %s/%s\n", md.md_name, md.md_uuid);
}
/*
* Let's check if such a device already is present. We check against
* uuid alone first because that's the true distinguishor. If that
* passes, then we check for name conflicts. If there are conflicts,
* modify the name.
*
* The whole purpose of this is to solve the problem that people don't
* pick good unique names, but good unique names (like uuids) are a
* pain to use. So, we allow people to build GEOMs with friendly names
* and uuids, and modify the names in case there's a collision.
*/
sc = NULL;
LIST_FOREACH(gp, &mp->geom, geom) {
sc = gp->softc;
if (sc == NULL) {
continue;
}
if (strncmp(md.md_uuid, sc->sc_uuid, sizeof(md.md_uuid)) == 0) {
break;
}
}
LIST_FOREACH(gp1, &mp->geom, geom) {
if (gp1 == gp) {
continue;
}
sc = gp1->softc;
if (sc == NULL) {
continue;
}
if (strncmp(md.md_name, sc->sc_name, sizeof(md.md_name)) == 0) {
break;
}
}
/*
* If gp is NULL, we had no extant MULTIPATH geom with this uuid.
*
* If gp1 is *not* NULL, that means we have a MULTIPATH geom extant
* with the same name (but a different UUID).
*
* If gp is NULL, then modify the name with a random number and
* complain, but allow the creation of the geom to continue.
*
* If gp is *not* NULL, just use the geom's name as we're attaching
* this disk to the (previously generated) name.
*/
if (gp1) {
sc = gp1->softc;
if (gp == NULL) {
char buf[16];
u_long rand = random();
snprintf(buf, sizeof (buf), "%s-%lu", md.md_name, rand);
printf("GEOM_MULTIPATH: geom %s/%s exists already\n",
sc->sc_name, sc->sc_uuid);
printf("GEOM_MULTIPATH: %s will be (temporarily) %s\n",
md.md_uuid, buf);
strlcpy(md.md_name, buf, sizeof (md.md_name));
} else {
strlcpy(md.md_name, sc->sc_name, sizeof (md.md_name));
}
}
if (gp == NULL) {
gp = g_multipath_create(mp, &md);
if (gp == NULL) {
printf("GEOM_MULTIPATH: cannot create geom %s/%s\n",
md.md_name, md.md_uuid);
return (NULL);
}
isnew = 1;
} else {
isnew = 0;
}
sc = gp->softc;
KASSERT(sc != NULL, ("sc is NULL"));
error = g_multipath_add_disk(gp, pp);
if (error != 0) {
if (isnew) {
g_multipath_destroy(gp);
}
return (NULL);
}
return (gp);
}
static void
g_multipath_ctl_create(struct gctl_req *req, struct g_class *mp)
{
struct g_geom *gp;
struct g_provider *pp0, *pp1;
struct g_multipath_metadata md;
const char *name, *mpname, *uuid;
static const char devpf[6] = "/dev/";
int *nargs, error;
g_topology_assert();
mpname = gctl_get_asciiparam(req, "arg0");
if (mpname == NULL) {
gctl_error(req, "No 'arg0' argument");
return;
}
nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
if (nargs == NULL) {
gctl_error(req, "No 'nargs' argument");
return;
}
if (*nargs != 4) {
gctl_error(req, "missing device or uuid arguments");
return;
}
name = gctl_get_asciiparam(req, "arg1");
if (name == NULL) {
gctl_error(req, "No 'arg1' argument");
return;
}
if (strncmp(name, devpf, 5) == 0) {
name += 5;
}
pp0 = g_provider_by_name(name);
if (pp0 == NULL) {
gctl_error(req, "Provider %s is invalid", name);
return;
}
name = gctl_get_asciiparam(req, "arg2");
if (name == NULL) {
gctl_error(req, "No 'arg2' argument");
return;
}
if (strncmp(name, devpf, 5) == 0) {
name += 5;
}
pp1 = g_provider_by_name(name);
if (pp1 == NULL) {
gctl_error(req, "Provider %s is invalid", name);
return;
}
uuid = gctl_get_asciiparam(req, "arg3");
if (uuid == NULL) {
gctl_error(req, "No uuid argument");
return;
}
if (strlen(uuid) != 36) {
gctl_error(req, "Malformed uuid argument");
return;
}
/*
* Check to make sure parameters from the two providers are the same
*/
if (pp0 == pp1) {
gctl_error(req, "providers %s and %s are the same",
pp0->name, pp1->name);
return;
}
if (pp0->mediasize != pp1->mediasize) {
gctl_error(req, "Provider %s is %jd; Provider %s is %jd",
pp0->name, (intmax_t) pp0->mediasize,
pp1->name, (intmax_t) pp1->mediasize);
return;
}
if (pp0->sectorsize != pp1->sectorsize) {
gctl_error(req, "Provider %s has sectorsize %u; Provider %s "
"has sectorsize %u", pp0->name, pp0->sectorsize,
pp1->name, pp1->sectorsize);
return;
}
/*
* cons up enough of a metadata structure to use.
*/
memset(&md, 0, sizeof(md));
md.md_size = pp0->mediasize;
md.md_sectorsize = pp0->sectorsize;
strncpy(md.md_name, mpname, sizeof (md.md_name));
strncpy(md.md_uuid, uuid, sizeof (md.md_uuid));
gp = g_multipath_create(mp, &md);
if (gp == NULL) {
return;
}
error = g_multipath_add_disk(gp, pp0);
if (error) {
g_multipath_destroy(gp);
return;
}
error = g_multipath_add_disk(gp, pp1);
if (error) {
g_multipath_destroy(gp);
return;
}
}
static struct g_geom *
g_multipath_find_geom(struct g_class *mp, const char *name)
{
struct g_geom *gp;
LIST_FOREACH(gp, &mp->geom, geom) {
if (strcmp(gp->name, name) == 0) {
return (gp);
}
}
return (NULL);
}
static void
g_multipath_ctl_destroy(struct gctl_req *req, struct g_class *mp)
{
struct g_geom *gp;
const char *name;
int error;
g_topology_assert();
name = gctl_get_asciiparam(req, "arg0");
if (name == NULL) {
gctl_error(req, "No 'arg0' argument");
return;
}
gp = g_multipath_find_geom(mp, name);
if (gp == NULL) {
gctl_error(req, "Device %s is invalid", name);
return;
}
error = g_multipath_destroy(gp);
if (error != 0) {
gctl_error(req, "failed to destroy %s (err=%d)", name, error);
}
}
static void
g_multipath_config(struct gctl_req *req, struct g_class *mp, const char *verb)
{
uint32_t *version;
g_topology_assert();
version = gctl_get_paraml(req, "version", sizeof(*version));
if (version == NULL) {
gctl_error(req, "No 'version' argument");
} else if (*version != G_MULTIPATH_VERSION) {
gctl_error(req, "Userland and kernel parts are out of sync");
} else if (strcmp(verb, "create") == 0) {
g_multipath_ctl_create(req, mp);
} else if (strcmp(verb, "destroy") == 0) {
g_multipath_ctl_destroy(req, mp);
} else {
gctl_error(req, "Unknown verb %s", verb);
}
}
DECLARE_GEOM_CLASS(g_multipath_class, g_multipath);

99
sys/geom/multipath/g_multipath.h Normal file
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@ -0,0 +1,99 @@
/*-
* Copyright (c) 2006-2007 Matthew Jacob <mjacob@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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.
*
* $FreeBSD$
*/
/*
* Based upon work by Pawel Jakub Dawidek <pjd@FreeBSD.org> for all of the
* fine geom examples, and by Poul Henning Kamp <phk@FreeBSD.org> for GEOM
* itself, all of which is most gratefully acknowledged.
*/
#ifndef _G_MULTIPATH_H_
#define _G_MULTIPATH_H_
#define G_MULTIPATH_CLASS_NAME "MULTIPATH"
#define G_MULTIPATH_VERSION 1
#define G_MULTIPATH_MAGIC "GEOM::MULTIPATH"
#include <sys/endian.h>
#ifdef _KERNEL
struct g_multipath_softc {
struct g_provider * pp;
struct g_consumer * cp_active;
char sc_name[16];
char sc_uuid[40];
};
#endif /* _KERNEL */
struct g_multipath_metadata {
char md_magic[16]; /* Magic Value */
char md_uuid[40]; /* more magic */
char md_name[16]; /* a friendly name */
uint32_t md_version; /* version */
uint32_t md_sectorsize; /* sectorsize of provider */
uint64_t md_size; /* absolute size of provider */
};
static __inline void
multipath_metadata_encode(const struct g_multipath_metadata *, u_char *);
static __inline void
multipath_metadata_decode(u_char *, struct g_multipath_metadata *);
static __inline void
multipath_metadata_encode(const struct g_multipath_metadata *md, u_char *data)
{
bcopy(md->md_magic, data, sizeof(md->md_magic));
data += sizeof(md->md_magic);
bcopy(md->md_uuid, data, sizeof(md->md_uuid));
data += sizeof(md->md_uuid);
bcopy(md->md_name, data, sizeof(md->md_name));
data += sizeof(md->md_name);
le32enc(data, md->md_version);
data += sizeof(md->md_version);
le32enc(data, md->md_sectorsize);
data += sizeof(md->md_sectorsize);
le64enc(data, md->md_size);
}
static __inline void
multipath_metadata_decode(u_char *data, struct g_multipath_metadata *md)
{
bcopy(data, md->md_magic, sizeof(md->md_magic));
data += sizeof(md->md_magic);
bcopy(data, md->md_uuid, sizeof(md->md_uuid));
data += sizeof(md->md_uuid);
bcopy(data, md->md_name, sizeof(md->md_name));
data += sizeof(md->md_name);
md->md_version = le32dec(data);
data += sizeof(md->md_version);
md->md_sectorsize = le32dec(data);
data += sizeof(md->md_sectorsize);
md->md_size = le64dec(data);
}
#endif /* _G_MULTIPATH_H_ */

1
sys/modules/geom/Makefile
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@ -12,6 +12,7 @@ SUBDIR= geom_bde \
geom_label \
geom_mbr \
geom_mirror \
geom_multipath \
geom_nop \
geom_pc98 \
geom_raid3 \

8
sys/modules/geom/geom_multipath/Makefile Normal file
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@ -0,0 +1,8 @@
# $FreeBSD$
.PATH: ${.CURDIR}/../../../geom/multipath
KMOD= geom_multipath
SRCS= g_multipath.c
.include <bsd.kmod.mk>