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freebsd-dev/sys/geom/geom_mbr.c
Attilio Rao 5d7380f8e3 Avoid to check the same cache line/variable from all the locking 
primitives by breaking stop_scheduler into a per-thread variable.
Also, store the new td_stopsched very close to td_*locks members as
they will be accessed mostly in the same codepaths as td_stopsched and
this results in avoiding a further cache-line pollution, possibly.

STOP_SCHEDULER() was pondered to use a new 'thread' argument, in order to
take advantage of already cached curthread, but in the end there should
not really be a performance benefit, while introducing a KPI breakage.

In collabouration with:	flo
Reviewed by:	avg
MFC after:	3 months (or never)
X-MFC:		r228424
2012-01-28 14:00:21 +00:00

523 lines
13 KiB
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/*-
* Copyright (c) 2002 Poul-Henning Kamp
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Poul-Henning Kamp
* and NAI Labs, the Security Research Division of Network Associates, Inc.
* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
* DARPA CHATS research program.
*
* 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 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/endian.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/bio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/md5.h>
#include <sys/proc.h>
#include <sys/diskmbr.h>
#include <sys/sbuf.h>
#include <geom/geom.h>
#include <geom/geom_slice.h>
FEATURE(geom_mbr, "GEOM DOS/MBR partitioning support");
#define MBR_CLASS_NAME "MBR"
#define MBREXT_CLASS_NAME "MBREXT"
static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
};
static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
};
static void
g_mbr_print(int i, struct dos_partition *dp)
{
printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
dp->dp_shd, DPSECT(dp->dp_ssect));
printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
dp->dp_ehd, DPSECT(dp->dp_esect));
printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
}
struct g_mbr_softc {
int type [NDOSPART];
u_int sectorsize;
u_char sec0[512];
u_char slicesum[16];
};
/*
* XXX: Add gctl_req arg and give good error msgs.
* XXX: Check that length argument does not bring boot code inside any slice.
*/
static int
g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused)
{
int i, error;
off_t l[NDOSPART];
struct dos_partition ndp[NDOSPART], *dp;
MD5_CTX md5sum;
g_topology_assert();
if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
return (EBUSY);
dp = ndp;
for (i = 0; i < NDOSPART; i++) {
dos_partition_dec(
sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
dp + i);
}
if ((!bcmp(dp, historical_bogus_partition_table,
sizeof historical_bogus_partition_table)) ||
(!bcmp(dp, historical_bogus_partition_table_fixed,
sizeof historical_bogus_partition_table_fixed))) {
/*
* We will not allow people to write these from "the inside",
* Since properly selfdestructing takes too much code. If
* people really want to do this, they cannot have any
* providers of this geom open, and in that case they can just
* as easily overwrite the MBR in the parent device.
*/
return(EBUSY);
}
for (i = 0; i < NDOSPART; i++) {
/*
* A Protective MBR (PMBR) has a single partition of
* type 0xEE spanning the whole disk. Such a MBR
* protects a GPT on the disk from MBR tools that
* don't know anything about GPT. We're interpreting
* it a bit more loosely: any partition of type 0xEE
* is to be skipped as it doesn't contain any data
* that we should care about. We still allow other
* partitions to be present in the MBR. A PMBR will
* be handled correctly anyway.
*/
if (dp[i].dp_typ == DOSPTYP_PMBR)
l[i] = 0;
else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
l[i] = 0;
else if (dp[i].dp_typ == 0)
l[i] = 0;
else
l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
(off_t)dp[i].dp_start * ms->sectorsize, l[i],
ms->sectorsize, "%ss%d", gp->name, 1 + i);
if (error)
return (error);
}
for (i = 0; i < NDOSPART; i++) {
ms->type[i] = dp[i].dp_typ;
g_slice_config(gp, i, G_SLICE_CONFIG_SET,
(off_t)dp[i].dp_start * ms->sectorsize, l[i],
ms->sectorsize, "%ss%d", gp->name, 1 + i);
}
bcopy(sec0, ms->sec0, 512);
/*
* Calculate MD5 from the first sector and use it for avoiding
* recursive slices creation.
*/
MD5Init(&md5sum);
MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
MD5Final(ms->slicesum, &md5sum);
return (0);
}
static int
g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
{
struct g_geom *gp;
struct g_mbr_softc *ms;
struct g_slicer *gsp;
struct g_consumer *cp;
int error, opened;
gp = pp->geom;
gsp = gp->softc;
ms = gsp->softc;
opened = 0;
error = 0;
switch(cmd) {
case DIOCSMBR: {
if (!(fflag & FWRITE))
return (EPERM);
DROP_GIANT();
g_topology_lock();
cp = LIST_FIRST(&gp->consumer);
if (cp->acw == 0) {
error = g_access(cp, 0, 1, 0);
if (error == 0)
opened = 1;
}
if (!error)
error = g_mbr_modify(gp, ms, data, 512);
if (!error)
error = g_write_data(cp, 0, data, 512);
if (opened)
g_access(cp, 0, -1 , 0);
g_topology_unlock();
PICKUP_GIANT();
return(error);
}
default:
return (ENOIOCTL);
}
}
static int
g_mbr_start(struct bio *bp)
{
struct g_provider *pp;
struct g_geom *gp;
struct g_mbr_softc *mp;
struct g_slicer *gsp;
int idx;
pp = bp->bio_to;
idx = pp->index;
gp = pp->geom;
gsp = gp->softc;
mp = gsp->softc;
if (bp->bio_cmd == BIO_GETATTR) {
if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
return (1);
if (g_handleattr_off_t(bp, "MBR::offset",
gsp->slices[idx].offset))
return (1);
if (g_handleattr(bp, "MBR::slicesum", mp->slicesum,
sizeof(mp->slicesum)))
return (1);
}
return (0);
}
static void
g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
{
struct g_mbr_softc *mp;
struct g_slicer *gsp;
gsp = gp->softc;
mp = gsp->softc;
g_slice_dumpconf(sb, indent, gp, cp, pp);
if (pp != NULL) {
if (indent == NULL)
sbuf_printf(sb, " ty %d", mp->type[pp->index]);
else
sbuf_printf(sb, "%s<type>%d</type>\n", indent,
mp->type[pp->index]);
}
}
static struct g_geom *
g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
{
struct g_geom *gp;
struct g_consumer *cp;
int error;
struct g_mbr_softc *ms;
u_int fwsectors, sectorsize;
u_char *buf;
u_char hash[16];
MD5_CTX md5sum;
g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME))
return (NULL);
gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
if (gp == NULL)
return (NULL);
g_topology_unlock();
do {
error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
if (error)
fwsectors = 17;
sectorsize = cp->provider->sectorsize;
if (sectorsize < 512)
break;
ms->sectorsize = sectorsize;
buf = g_read_data(cp, 0, sectorsize, NULL);
if (buf == NULL)
break;
/*
* Calculate MD5 from the first sector and use it for avoiding
* recursive slices creation.
*/
bcopy(buf, ms->sec0, 512);
MD5Init(&md5sum);
MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
MD5Final(ms->slicesum, &md5sum);
error = g_getattr("MBR::slicesum", cp, &hash);
if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) {
g_free(buf);
break;
}
g_topology_lock();
g_mbr_modify(gp, ms, buf, 512);
g_topology_unlock();
g_free(buf);
break;
} while (0);
g_topology_lock();
g_access(cp, -1, 0, 0);
if (LIST_EMPTY(&gp->provider)) {
g_slice_spoiled(cp);
return (NULL);
}
return (gp);
}
static void
g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb)
{
struct g_geom *gp;
struct g_consumer *cp;
struct g_mbr_softc *ms;
struct g_slicer *gsp;
int opened = 0, error = 0;
void *data;
int len;
g_topology_assert();
gp = gctl_get_geom(req, mp, "geom");
if (gp == NULL)
return;
if (strcmp(verb, "write MBR")) {
gctl_error(req, "Unknown verb");
return;
}
gsp = gp->softc;
ms = gsp->softc;
data = gctl_get_param(req, "data", &len);
if (data == NULL)
return;
if (len < 512 || (len % 512)) {
gctl_error(req, "Wrong request length");
return;
}
cp = LIST_FIRST(&gp->consumer);
if (cp->acw == 0) {
error = g_access(cp, 0, 1, 0);
if (error == 0)
opened = 1;
}
if (!error)
error = g_mbr_modify(gp, ms, data, len);
if (error)
gctl_error(req, "conflict with open slices");
if (!error)
error = g_write_data(cp, 0, data, len);
if (error)
gctl_error(req, "sector zero write failed");
if (opened)
g_access(cp, 0, -1 , 0);
return;
}
static struct g_class g_mbr_class = {
.name = MBR_CLASS_NAME,
.version = G_VERSION,
.taste = g_mbr_taste,
.dumpconf = g_mbr_dumpconf,
.ctlreq = g_mbr_config,
.ioctl = g_mbr_ioctl,
};
DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
#define NDOSEXTPART 32
struct g_mbrext_softc {
int type [NDOSEXTPART];
};
static int
g_mbrext_start(struct bio *bp)
{
struct g_provider *pp;
struct g_geom *gp;
struct g_mbrext_softc *mp;
struct g_slicer *gsp;
int idx;
pp = bp->bio_to;
idx = pp->index;
gp = pp->geom;
gsp = gp->softc;
mp = gsp->softc;
if (bp->bio_cmd == BIO_GETATTR) {
if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
return (1);
}
return (0);
}
static void
g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
{
struct g_mbrext_softc *mp;
struct g_slicer *gsp;
g_slice_dumpconf(sb, indent, gp, cp, pp);
gsp = gp->softc;
mp = gsp->softc;
if (pp != NULL) {
if (indent == NULL)
sbuf_printf(sb, " ty %d", mp->type[pp->index]);
else
sbuf_printf(sb, "%s<type>%d</type>\n", indent,
mp->type[pp->index]);
}
}
static struct g_geom *
g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
{
struct g_geom *gp;
struct g_consumer *cp;
int error, i, slice;
struct g_mbrext_softc *ms;
off_t off;
u_char *buf;
struct dos_partition dp[4];
u_int fwsectors, sectorsize;
g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
return (NULL);
gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
g_mbrext_start);
if (gp == NULL)
return (NULL);
g_topology_unlock();
off = 0;
slice = 0;
do {
error = g_getattr("MBR::type", cp, &i);
if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
break;
error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
if (error)
fwsectors = 17;
sectorsize = cp->provider->sectorsize;
if (sectorsize != 512)
break;
for (;;) {
buf = g_read_data(cp, off, sectorsize, NULL);
if (buf == NULL)
break;
if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
g_free(buf);
break;
}
for (i = 0; i < NDOSPART; i++)
dos_partition_dec(
buf + DOSPARTOFF +
i * sizeof(struct dos_partition), dp + i);
g_free(buf);
if (0 && bootverbose) {
printf("MBREXT Slice %d on %s:\n",
slice + 5, gp->name);
g_mbr_print(0, dp);
g_mbr_print(1, dp + 1);
}
if ((dp[0].dp_flag & 0x7f) == 0 &&
dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
g_topology_lock();
g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
(((off_t)dp[0].dp_start) << 9ULL) + off,
((off_t)dp[0].dp_size) << 9ULL,
sectorsize,
"%*.*s%d",
strlen(gp->name) - 1,
strlen(gp->name) - 1,
gp->name,
slice + 5);
g_topology_unlock();
ms->type[slice] = dp[0].dp_typ;
slice++;
}
if (dp[1].dp_flag != 0)
break;
if (dp[1].dp_typ != DOSPTYP_EXT &&
dp[1].dp_typ != DOSPTYP_EXTLBA)
break;
if (dp[1].dp_size == 0)
break;
off = ((off_t)dp[1].dp_start) << 9ULL;
}
break;
} while (0);
g_topology_lock();
g_access(cp, -1, 0, 0);
if (LIST_EMPTY(&gp->provider)) {
g_slice_spoiled(cp);
return (NULL);
}
return (gp);
}
static struct g_class g_mbrext_class = {
.name = MBREXT_CLASS_NAME,
.version = G_VERSION,
.taste = g_mbrext_taste,
.dumpconf = g_mbrext_dumpconf,
};
DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
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