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scsi: add multipath support to qemu-pr-helper 

Proper support of persistent reservation for multipath devices requires
communication with the multipath daemon, so that the reservation is
registered and applied when a path comes up.  The device mapper
utilities provide a library to do so; this patch makes qemu-pr-helper.c
detect multipath devices and, when one is found, delegate the operation
to libmpathpersist.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-08-22 06:50:55 +02:00
parent b855f8d175
commit fe8fc5ae5c
6 changed files with 433 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Makefile
View File

@ -373,6 +373,9 @@ fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o fsdev/9p-marshal
fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap
scsi/qemu-pr-helper$(EXESUF): scsi/qemu-pr-helper.o scsi/utils.o $(crypto-obj-y) $(io-obj-y) $(qom-obj-y) $(COMMON_LDADDS)
ifdef CONFIG_MPATH
scsi/qemu-pr-helper$(EXESUF): LIBS += -ludev -lmultipath -lmpathpersist
endif
qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx $(SRC_PATH)/scripts/hxtool
$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@,"GEN","$@")

46
configure vendored
View File

@ -290,6 +290,7 @@ netmap="no"
sdl=""
sdlabi=""
virtfs=""
mpath=""
vnc="yes"
sparse="no"
vde=""
@ -936,6 +937,10 @@ for opt do
;;
--enable-virtfs) virtfs="yes"
;;
--disable-mpath) mpath="no"
;;
--enable-mpath) mpath="yes"
;;
--disable-vnc) vnc="no"
;;
--enable-vnc) vnc="yes"
@ -1479,6 +1484,7 @@ disabled with --disable-FEATURE, default is enabled if available:
vnc-png PNG compression for VNC server
cocoa Cocoa UI (Mac OS X only)
virtfs VirtFS
mpath Multipath persistent reservation passthrough
xen xen backend driver support
xen-pci-passthrough
brlapi BrlAPI (Braile)
@ -3299,6 +3305,30 @@ else
"Please install the pixman devel package."
fi
##########################################
# libmpathpersist probe
if test "$mpath" != "no" ; then
cat > $TMPC <<EOF
#include <libudev.h>
#include <mpath_persist.h>
unsigned mpath_mx_alloc_len = 1024;
int logsink;
int main(void) {
struct udev *udev = udev_new();
mpath_lib_init(udev);
return 0;
}
EOF
if compile_prog "" "-ludev -lmultipath -lmpathpersist" ; then
mpathpersist=yes
else
mpathpersist=no
fi
else
mpathpersist=no
fi
##########################################
# libcap probe
@ -5044,12 +5074,24 @@ if test "$softmmu" = yes ; then
fi
virtfs=no
fi
if test "$mpath" != no && test "$mpathpersist" = yes ; then
mpath=yes
else
if test "$mpath" = yes; then
error_exit "Multipath requires libmpathpersist devel"
fi
mpath=no
fi
tools="$tools scsi/qemu-pr-helper\$(EXESUF)"
else
if test "$virtfs" = yes; then
error_exit "VirtFS is supported only on Linux"
fi
virtfs=no
if test "$mpath" = yes; then
error_exit "Multipath is supported only on Linux"
fi
mpath=no
fi
fi
@ -5295,6 +5337,7 @@ echo "Audio drivers $audio_drv_list"
echo "Block whitelist (rw) $block_drv_rw_whitelist"
echo "Block whitelist (ro) $block_drv_ro_whitelist"
echo "VirtFS support $virtfs"
echo "Multipath support $mpath"
echo "VNC support $vnc"
if test "$vnc" = "yes" ; then
echo "VNC SASL support $vnc_sasl"
@ -5738,6 +5781,9 @@ fi
if test "$virtfs" = "yes" ; then
echo "CONFIG_VIRTFS=y" >> $config_host_mak
fi
if test "$mpath" = "yes" ; then
echo "CONFIG_MPATH=y" >> $config_host_mak
fi
if test "$vhost_scsi" = "yes" ; then
echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
fi

27
docs/pr-manager.rst
View File

@ -60,6 +60,7 @@ system service and supports the following option:
-d, --daemon run in the background
-q, --quiet decrease verbosity
-v, --verbose increase verbosity
-f, --pidfile=path PID file when running as a daemon
-k, --socket=path path to the socket
-T, --trace=trace-opts tracing options
@ -82,3 +83,29 @@ its operation. To do this, add the following options:
-u, --user=user user to drop privileges to
-g, --group=group group to drop privileges to
---------------------------------------------
Multipath devices and persistent reservations
---------------------------------------------
Proper support of persistent reservation for multipath devices requires
communication with the multipath daemon, so that the reservation is
registered and applied when a path is newly discovered or becomes online
again. :command:`qemu-pr-helper` can do this if the ``libmpathpersist``
library was available on the system at build time.
As of August 2017, a reservation key must be specified in ``multipath.conf``
for ``multipathd`` to check for persistent reservation for newly
discovered paths or reinstated paths. The attribute can be added
to the ``defaults`` section or the ``multipaths`` section; for example::
multipaths {
multipath {
wwid XXXXXXXXXXXXXXXX
alias yellow
reservation_key 0x123abc
}
}
Linking :program:`qemu-pr-helper` to ``libmpathpersist`` does not impede
its usage on regular SCSI devices.

4
include/scsi/utils.h
View File

@ -72,10 +72,14 @@ extern const struct SCSISense sense_code_IO_ERROR;
extern const struct SCSISense sense_code_I_T_NEXUS_LOSS;
/* Command aborted, Logical Unit failure */
extern const struct SCSISense sense_code_LUN_FAILURE;
/* Command aborted, LUN Communication failure */
extern const struct SCSISense sense_code_LUN_COMM_FAILURE;
/* Command aborted, Overlapped Commands Attempted */
extern const struct SCSISense sense_code_OVERLAPPED_COMMANDS;
/* LUN not ready, Capacity data has changed */
extern const struct SCSISense sense_code_CAPACITY_CHANGED;
/* Unit attention, SCSI bus reset */
extern const struct SCSISense sense_code_SCSI_BUS_RESET;
/* LUN not ready, Medium not present */
extern const struct SCSISense sense_code_UNIT_ATTENTION_NO_MEDIUM;
/* Unit attention, Power on, reset or bus device reset occurred */

346
scsi/qemu-pr-helper.c
View File

@ -30,6 +30,12 @@
#include <pwd.h>
#include <grp.h>
#ifdef CONFIG_MPATH
#include <libudev.h>
#include <mpath_cmd.h>
#include <mpath_persist.h>
#endif
#include "qapi/error.h"
#include "qemu-common.h"
#include "qemu/cutils.h"
@ -60,6 +66,7 @@ static enum { RUNNING, TERMINATE, TERMINATING } state;
static QIOChannelSocket *server_ioc;
static int server_watch;
static int num_active_sockets = 1;
static int noisy;
static int verbose;
#ifdef CONFIG_LIBCAP
@ -204,9 +211,316 @@ static int do_sgio(int fd, const uint8_t *cdb, uint8_t *sense,
return r;
}
/* Device mapper interface */
#ifdef CONFIG_MPATH
#define CONTROL_PATH "/dev/mapper/control"
typedef struct DMData {
struct dm_ioctl dm;
uint8_t data[1024];
} DMData;
static int control_fd;
static void *dm_ioctl(int ioc, struct dm_ioctl *dm)
{
static DMData d;
memcpy(&d.dm, dm, sizeof(d.dm));
QEMU_BUILD_BUG_ON(sizeof(d.data) < sizeof(struct dm_target_spec));
d.dm.version[0] = DM_VERSION_MAJOR;
d.dm.version[1] = 0;
d.dm.version[2] = 0;
d.dm.data_size = 1024;
d.dm.data_start = offsetof(DMData, data);
if (ioctl(control_fd, ioc, &d) < 0) {
return NULL;
}
memcpy(dm, &d.dm, sizeof(d.dm));
return &d.data;
}
static void *dm_dev_ioctl(int fd, int ioc, struct dm_ioctl *dm)
{
struct stat st;
int r;
r = fstat(fd, &st);
if (r < 0) {
perror("fstat");
exit(1);
}
dm->dev = st.st_rdev;
return dm_ioctl(ioc, dm);
}
static void dm_init(void)
{
control_fd = open(CONTROL_PATH, O_RDWR);
if (control_fd < 0) {
perror("Cannot open " CONTROL_PATH);
exit(1);
}
struct dm_ioctl dm = { 0 };
if (!dm_ioctl(DM_VERSION, &dm)) {
perror("ioctl");
exit(1);
}
if (dm.version[0] != DM_VERSION_MAJOR) {
fprintf(stderr, "Unsupported device mapper interface");
exit(1);
}
}
/* Variables required by libmultipath and libmpathpersist. */
QEMU_BUILD_BUG_ON(PR_HELPER_DATA_SIZE > MPATH_MAX_PARAM_LEN);
unsigned mpath_mx_alloc_len = PR_HELPER_DATA_SIZE;
int logsink;
static void multipath_pr_init(void)
{
static struct udev *udev;
udev = udev_new();
mpath_lib_init(udev);
}
static int is_mpath(int fd)
{
struct dm_ioctl dm = { .flags = DM_NOFLUSH_FLAG };
struct dm_target_spec *tgt;
tgt = dm_dev_ioctl(fd, DM_TABLE_STATUS, &dm);
if (!tgt) {
if (errno == ENXIO) {
return 0;
}
perror("ioctl");
exit(EXIT_FAILURE);
}
return !strncmp(tgt->target_type, "multipath", DM_MAX_TYPE_NAME);
}
static int mpath_reconstruct_sense(int fd, int r, uint8_t *sense)
{
switch (r) {
case MPATH_PR_SUCCESS:
return GOOD;
case MPATH_PR_SENSE_NOT_READY:
case MPATH_PR_SENSE_MEDIUM_ERROR:
case MPATH_PR_SENSE_HARDWARE_ERROR:
case MPATH_PR_SENSE_ABORTED_COMMAND:
{
/* libmpathpersist ate the exact sense. Try to find it by
* issuing TEST UNIT READY.
*/
uint8_t cdb[6] = { TEST_UNIT_READY };
int sz = 0;
return do_sgio(fd, cdb, sense, NULL, &sz, SG_DXFER_NONE);
}
case MPATH_PR_SENSE_UNIT_ATTENTION:
/* Congratulations libmpathpersist, you ruined the Unit Attention...
* Return a heavyweight one.
*/
scsi_build_sense(sense, SENSE_CODE(SCSI_BUS_RESET));
return CHECK_CONDITION;
case MPATH_PR_SENSE_INVALID_OP:
/* Only one valid sense. */
scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
return CHECK_CONDITION;
case MPATH_PR_ILLEGAL_REQ:
/* Guess. */
scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
return CHECK_CONDITION;
case MPATH_PR_NO_SENSE:
scsi_build_sense(sense, SENSE_CODE(NO_SENSE));
return CHECK_CONDITION;
case MPATH_PR_RESERV_CONFLICT:
return RESERVATION_CONFLICT;
case MPATH_PR_OTHER:
default:
scsi_build_sense(sense, SENSE_CODE(LUN_COMM_FAILURE));
return CHECK_CONDITION;
}
}
static int multipath_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
uint8_t *data, int sz)
{
int rq_servact = cdb[1];
struct prin_resp resp;
size_t written;
int r;
switch (rq_servact) {
case MPATH_PRIN_RKEY_SA:
case MPATH_PRIN_RRES_SA:
case MPATH_PRIN_RCAP_SA:
break;
case MPATH_PRIN_RFSTAT_SA:
/* Nobody implements it anyway, so bail out. */
default:
/* Cannot parse any other output. */
scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
return CHECK_CONDITION;
}
r = mpath_persistent_reserve_in(fd, rq_servact, &resp, noisy, verbose);
if (r == MPATH_PR_SUCCESS) {
switch (rq_servact) {
case MPATH_PRIN_RKEY_SA:
case MPATH_PRIN_RRES_SA: {
struct prin_readdescr *out = &resp.prin_descriptor.prin_readkeys;
assert(sz >= 8);
written = MIN(out->additional_length + 8, sz);
stl_be_p(&data[0], out->prgeneration);
stl_be_p(&data[4], out->additional_length);
memcpy(&data[8], out->key_list, written - 8);
break;
}
case MPATH_PRIN_RCAP_SA: {
struct prin_capdescr *out = &resp.prin_descriptor.prin_readcap;
assert(sz >= 6);
written = 6;
stw_be_p(&data[0], out->length);
data[2] = out->flags[0];
data[3] = out->flags[1];
stw_be_p(&data[4], out->pr_type_mask);
break;
}
default:
scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
return CHECK_CONDITION;
}
assert(written <= sz);
memset(data + written, 0, sz - written);
}
return mpath_reconstruct_sense(fd, r, sense);
}
static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
const uint8_t *param, int sz)
{
int rq_servact = cdb[1];
int rq_scope = cdb[2] >> 4;
int rq_type = cdb[2] & 0xf;
struct prout_param_descriptor paramp;
char transportids[PR_HELPER_DATA_SIZE];
int r;
switch (rq_servact) {
case MPATH_PROUT_REG_SA:
case MPATH_PROUT_RES_SA:
case MPATH_PROUT_REL_SA:
case MPATH_PROUT_CLEAR_SA:
case MPATH_PROUT_PREE_SA:
case MPATH_PROUT_PREE_AB_SA:
case MPATH_PROUT_REG_IGN_SA:
break;
case MPATH_PROUT_REG_MOV_SA:
/* Not supported by struct prout_param_descriptor. */
default:
/* Cannot parse any other input. */
scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
return CHECK_CONDITION;
}
/* Convert input data, especially transport IDs, to the structs
* used by libmpathpersist (which, of course, will immediately
* do the opposite).
*/
memset(&paramp, 0, sizeof(paramp));
memcpy(&paramp.key, &param[0], 8);
memcpy(&paramp.sa_key, &param[8], 8);
paramp.sa_flags = param[10];
if (sz > PR_OUT_FIXED_PARAM_SIZE) {
size_t transportid_len;
int i, j;
if (sz < PR_OUT_FIXED_PARAM_SIZE + 4) {
scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
return CHECK_CONDITION;
}
transportid_len = ldl_be_p(&param[24]) + PR_OUT_FIXED_PARAM_SIZE + 4;
if (transportid_len > sz) {
scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
return CHECK_CONDITION;
}
for (i = PR_OUT_FIXED_PARAM_SIZE + 4, j = 0; i < transportid_len; ) {
struct transportid *id = (struct transportid *) &transportids[j];
int len;
id->format_code = param[i] & 0xc0;
id->protocol_id = param[i] & 0x0f;
switch (param[i] & 0xcf) {
case 0:
/* FC transport. */
if (i + 24 > transportid_len) {
goto illegal_req;
}
memcpy(id->n_port_name, &param[i + 8], 8);
j += offsetof(struct transportid, n_port_name[8]);
i += 24;
break;
case 3:
case 0x43:
/* iSCSI transport. */
len = lduw_be_p(&param[i + 2]);
if (len > 252 || (len & 3) || i + len + 4 > transportid_len) {
/* For format code 00, the standard says the maximum is 223
* plus the NUL terminator. For format code 01 there is no
* maximum length, but libmpathpersist ignores the first
* byte of id->iscsi_name so our maximum is 252.
*/
goto illegal_req;
}
if (memchr(&param[i + 4], 0, len) == NULL) {
goto illegal_req;
}
memcpy(id->iscsi_name, &param[i + 2], len + 2);
j += offsetof(struct transportid, iscsi_name[len + 2]);
i += len + 4;
break;
case 6:
/* SAS transport. */
if (i + 24 > transportid_len) {
goto illegal_req;
}
memcpy(id->sas_address, &param[i + 4], 8);
j += offsetof(struct transportid, sas_address[8]);
i += 24;
break;
default:
illegal_req:
scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
return CHECK_CONDITION;
}
paramp.trnptid_list[paramp.num_transportid++] = id;
}
}
r = mpath_persistent_reserve_out(fd, rq_servact, rq_scope, rq_type,
&paramp, noisy, verbose);
return mpath_reconstruct_sense(fd, r, sense);
}
#endif
static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
uint8_t *data, int *resp_sz)
{
#ifdef CONFIG_MPATH
if (is_mpath(fd)) {
/* multipath_pr_in fills the whole input buffer. */
return multipath_pr_in(fd, cdb, sense, data, *resp_sz);
}
#endif
return do_sgio(fd, cdb, sense, data, resp_sz,
SG_DXFER_FROM_DEV);
}
@ -214,7 +528,14 @@ static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
static int do_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
const uint8_t *param, int sz)
{
int resp_sz = sz;
int resp_sz;
#ifdef CONFIG_MPATH
if (is_mpath(fd)) {
return multipath_pr_out(fd, cdb, sense, param, sz);
}
#endif
resp_sz = sz;
return do_sgio(fd, cdb, sense, (uint8_t *)param, &resp_sz,
SG_DXFER_TO_DEV);
}
@ -525,6 +846,14 @@ static int drop_privileges(void)
return -1;
}
#ifdef CONFIG_MPATH
/* For /dev/mapper/control ioctls */
if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
CAP_SYS_ADMIN) < 0) {
return -1;
}
#endif
/* Change user/group id, retaining the capabilities. Because file descriptors
* are passed via SCM_RIGHTS, we don't need supplementary groups (and in
* fact the helper can run as "nobody").
@ -541,7 +870,7 @@ static int drop_privileges(void)
int main(int argc, char **argv)
{
const char *sopt = "hVk:fdT:u:g:q";
const char *sopt = "hVk:fdT:u:g:vq";
struct option lopt[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
@ -551,10 +880,12 @@ int main(int argc, char **argv)
{ "trace", required_argument, NULL, 'T' },
{ "user", required_argument, NULL, 'u' },
{ "group", required_argument, NULL, 'g' },
{ "verbose", no_argument, NULL, 'v' },
{ "quiet", no_argument, NULL, 'q' },
{ NULL, 0, NULL, 0 }
};
int opt_ind = 0;
int loglevel = 1;
int quiet = 0;
int ch;
Error *local_err = NULL;
@ -631,6 +962,9 @@ int main(int argc, char **argv)
case 'q':
quiet = 1;
break;
case 'v':
++loglevel;
break;
case 'T':
g_free(trace_file);
trace_file = trace_opt_parse(optarg);
@ -650,7 +984,8 @@ int main(int argc, char **argv)
}
/* set verbosity */
verbose = !quiet;
noisy = !quiet && (loglevel >= 3);
verbose = quiet ? 0 : MIN(loglevel, 3);
if (!trace_init_backends()) {
exit(EXIT_FAILURE);
@ -658,6 +993,11 @@ int main(int argc, char **argv)
trace_init_file(trace_file);
qemu_set_log(LOG_TRACE);
#ifdef CONFIG_MPATH
dm_init();
multipath_pr_init();
#endif
socket_activation = check_socket_activation();
if (socket_activation == 0) {
SocketAddress saddr;

10
scsi/utils.c
View File

@ -206,6 +206,11 @@ const struct SCSISense sense_code_OVERLAPPED_COMMANDS = {
.key = ABORTED_COMMAND, .asc = 0x4e, .ascq = 0x00
};
/* Command aborted, LUN Communication Failure */
const struct SCSISense sense_code_LUN_COMM_FAILURE = {
.key = ABORTED_COMMAND, .asc = 0x08, .ascq = 0x00
};
/* Unit attention, Capacity data has changed */
const struct SCSISense sense_code_CAPACITY_CHANGED = {
.key = UNIT_ATTENTION, .asc = 0x2a, .ascq = 0x09
@ -216,6 +221,11 @@ const struct SCSISense sense_code_RESET = {
.key = UNIT_ATTENTION, .asc = 0x29, .ascq = 0x00
};
/* Unit attention, SCSI bus reset */
const struct SCSISense sense_code_SCSI_BUS_RESET = {
.key = UNIT_ATTENTION, .asc = 0x29, .ascq = 0x02
};
/* Unit attention, No medium */
const struct SCSISense sense_code_UNIT_ATTENTION_NO_MEDIUM = {
.key = UNIT_ATTENTION, .asc = 0x3a, .ascq = 0x00