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lvm2/lib/cache/lvmetad.c
David Teigland 32e22a0037 lvmlockd: rescan lockd VG in two new cases
Previously, a command would only rescan a lockd VG
when lvmetad returned the "vg_invalid" flag indicating
that the cached copy was invalid (which is done by
lvmlockd.)  This is still the only usual reason for
rescanning a lockd VG, but two new special cases are
added where we also do the rescan:

. When the --shared option is used to display lockd VGs
  from hosts not using lvmlockd.  This is the same case
  as using --foreign to display foreign VGs, but --shared
  was missing the corresponding bits to rescan the VGs.

. When a lockd VG is allowed to be read for displaying
  after failing to acquire the lock from lvmlockd.  In
  this case, the usual mechanism for validating the
  cache is missed, so assume the cache would have been
  invalidated.  (This had been a previous todo item
  that was lost during other cleanup.)

These were long-standing todos that were lost track of.
2015-08-27 10:27:24 -05:00

1687 lines
46 KiB
C

/*
* Copyright (C) 2012 Red Hat, Inc.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "toolcontext.h"
#include "metadata.h"
#include "device.h"
#include "lvmetad.h"
#include "lvmcache.h"
#include "lvmetad-client.h"
#include "format-text.h" // TODO for disk_locn, used as a DA representation
#include "crc.h"
#include "lvm-signal.h"
#include "lvmlockd.h"
#define SCAN_TIMEOUT_SECONDS 80
#define MAX_RESCANS 10 /* Maximum number of times to scan all PVs and retry if the daemon returns a token mismatch error */
static daemon_handle _lvmetad = { .error = 0 };
static int _lvmetad_use = 0;
static int _lvmetad_connected = 0;
static char *_lvmetad_token = NULL;
static const char *_lvmetad_socket = NULL;
static struct cmd_context *_lvmetad_cmd = NULL;
static struct volume_group *lvmetad_pvscan_vg(struct cmd_context *cmd, struct volume_group *vg);
void lvmetad_disconnect(void)
{
if (_lvmetad_connected)
daemon_close(_lvmetad);
_lvmetad_connected = 0;
}
void lvmetad_init(struct cmd_context *cmd)
{
if (!_lvmetad_use && !access(getenv("LVM_LVMETAD_PIDFILE") ? : LVMETAD_PIDFILE, F_OK))
log_warn("WARNING: lvmetad is running but disabled."
" Restart lvmetad before enabling it!");
if (_lvmetad_connected)
log_debug(INTERNAL_ERROR "Refreshing lvmetad global handle while connection with the daemon is active");
_lvmetad_cmd = cmd;
}
static void _lvmetad_connect(void)
{
if (!_lvmetad_use || !_lvmetad_socket || _lvmetad_connected)
return;
_lvmetad = lvmetad_open(_lvmetad_socket);
if (_lvmetad.socket_fd >= 0 && !_lvmetad.error) {
log_debug_lvmetad("Successfully connected to lvmetad on fd %d.",
_lvmetad.socket_fd);
_lvmetad_connected = 1;
}
}
void lvmetad_connect_or_warn(void)
{
if (!_lvmetad_use)
return;
if (!_lvmetad_connected && !_lvmetad.error) {
_lvmetad_connect();
if ((_lvmetad.socket_fd < 0 || _lvmetad.error))
log_warn("WARNING: Failed to connect to lvmetad. Falling back to internal scanning.");
}
}
int lvmetad_used(void)
{
return _lvmetad_use;
}
int lvmetad_socket_present(void)
{
const char *socket = _lvmetad_socket ?: LVMETAD_SOCKET;
int r;
if ((r = access(socket, F_OK)) && errno != ENOENT)
log_sys_error("lvmetad_socket_present", "");
return !r;
}
int lvmetad_active(void)
{
lvmetad_connect_or_warn();
return _lvmetad_connected;
}
void lvmetad_set_active(struct cmd_context *cmd, int active)
{
_lvmetad_use = active;
if (!active && lvmetad_active())
lvmetad_disconnect();
if (cmd && !refresh_filters(cmd))
stack;
}
/*
* Use a crc of the strings in the filter as the lvmetad token.
*/
void lvmetad_set_token(const struct dm_config_value *filter)
{
int ft = 0;
dm_free(_lvmetad_token);
while (filter && filter->type == DM_CFG_STRING) {
ft = calc_crc(ft, (const uint8_t *) filter->v.str, strlen(filter->v.str));
filter = filter->next;
}
if (dm_asprintf(&_lvmetad_token, "filter:%u", ft) < 0)
log_warn("WARNING: Failed to set lvmetad token. Out of memory?");
}
void lvmetad_release_token(void)
{
dm_free(_lvmetad_token);
_lvmetad_token = NULL;
}
void lvmetad_set_socket(const char *sock)
{
_lvmetad_socket = sock;
}
static int _lvmetad_pvscan_all_devs(struct cmd_context *cmd, activation_handler handler,
int ignore_obsolete);
static daemon_reply _lvmetad_send(const char *id, ...)
{
va_list ap;
daemon_reply repl = { 0 };
daemon_request req;
unsigned num_rescans = 0;
unsigned total_usecs_waited = 0;
unsigned max_remaining_sleep_times = 1;
unsigned wait_usecs;
retry:
req = daemon_request_make(id);
if (_lvmetad_token && !daemon_request_extend(req, "token = %s", _lvmetad_token, NULL)) {
repl.error = ENOMEM;
return repl;
}
va_start(ap, id);
daemon_request_extend_v(req, ap);
va_end(ap);
repl = daemon_send(_lvmetad, req);
daemon_request_destroy(req);
/*
* If another process is trying to scan, it might have the
* same future token id and it's better to wait and avoid doing
* the work multiple times. For the case where the future token is
* different, the wait is randomized so that multiple waiting
* processes do not start scanning all at once.
*
* If the token is mismatched because of global_filter changes,
* we re-scan immediately, but if we lose the potential race for
* the update, we back off for a short while (0.05-0.5 seconds) and
* try again.
*/
if (!repl.error && !strcmp(daemon_reply_str(repl, "response", ""), "token_mismatch") &&
num_rescans < MAX_RESCANS && total_usecs_waited < (SCAN_TIMEOUT_SECONDS * 1000000) && !test_mode()) {
if (!strcmp(daemon_reply_str(repl, "expected", ""), "update in progress") ||
max_remaining_sleep_times) {
wait_usecs = 50000 + lvm_even_rand(&_lvmetad_cmd->rand_seed, 450000); /* between 0.05s and 0.5s */
(void) usleep(wait_usecs);
total_usecs_waited += wait_usecs;
if (max_remaining_sleep_times)
max_remaining_sleep_times--; /* Sleep once before rescanning the first time, then 5 times each time after that. */
} else {
/* If the re-scan fails here, we try again later. */
(void) _lvmetad_pvscan_all_devs(_lvmetad_cmd, NULL, 0);
num_rescans++;
max_remaining_sleep_times = 5;
}
daemon_reply_destroy(repl);
goto retry;
}
return repl;
}
static int _token_update(void)
{
daemon_reply repl;
log_debug_lvmetad("Sending updated token to lvmetad: %s", _lvmetad_token ? : "<NONE>");
repl = _lvmetad_send("token_update", NULL);
if (repl.error || strcmp(daemon_reply_str(repl, "response", ""), "OK")) {
daemon_reply_destroy(repl);
return 0;
}
daemon_reply_destroy(repl);
return 1;
}
/*
* Helper; evaluate the reply from lvmetad, check for errors, print diagnostics
* and return a summary success/failure exit code.
*
* If found is set, *found indicates whether or not device exists,
* and missing device is not treated as an error.
*/
static int _lvmetad_handle_reply(daemon_reply reply, const char *action, const char *object,
int *found)
{
if (reply.error) {
log_error("Request to %s %s%sin lvmetad gave response %s.",
action, object, *object ? " " : "", strerror(reply.error));
return 0;
}
/* All OK? */
if (!strcmp(daemon_reply_str(reply, "response", ""), "OK")) {
if (found)
*found = 1;
return 1;
}
/* Unknown device permitted? */
if (found && !strcmp(daemon_reply_str(reply, "response", ""), "unknown")) {
log_very_verbose("Request to %s %s%sin lvmetad did not find any matching object.",
action, object, *object ? " " : "");
*found = 0;
return 1;
}
log_error("Request to %s %s%sin lvmetad gave response %s. Reason: %s",
action, object, *object ? " " : "",
daemon_reply_str(reply, "response", "<missing>"),
daemon_reply_str(reply, "reason", "<missing>"));
return 0;
}
static int _read_mda(struct lvmcache_info *info,
struct format_type *fmt,
const struct dm_config_node *cn)
{
struct metadata_area_ops *ops;
dm_list_iterate_items(ops, &fmt->mda_ops)
if (ops->mda_import_text && ops->mda_import_text(info, cn))
return 1;
return 0;
}
static int _pv_populate_lvmcache(struct cmd_context *cmd,
struct dm_config_node *cn,
struct format_type *fmt, dev_t fallback)
{
struct device *dev, *dev_alternate, *dev_alternate_cache = NULL;
struct label *label;
struct id pvid, vgid;
char mda_id[32];
char da_id[32];
int i = 0;
struct dm_config_node *mda, *da;
struct dm_config_node *alt_devices = dm_config_find_node(cn->child, "devices_alternate");
struct dm_config_value *alt_device = NULL;
uint64_t offset, size;
struct lvmcache_info *info, *info_alternate;
const char *pvid_txt = dm_config_find_str(cn->child, "id", NULL),
*vgid_txt = dm_config_find_str(cn->child, "vgid", NULL),
*vgname = dm_config_find_str(cn->child, "vgname", NULL),
*fmt_name = dm_config_find_str(cn->child, "format", NULL);
dev_t devt = dm_config_find_int(cn->child, "device", 0);
uint64_t devsize = dm_config_find_int64(cn->child, "dev_size", 0),
label_sector = dm_config_find_int64(cn->child, "label_sector", 0);
if (!fmt && fmt_name)
fmt = get_format_by_name(cmd, fmt_name);
if (!fmt) {
log_error("PV %s not recognised. Is the device missing?", pvid_txt);
return 0;
}
dev = dev_cache_get_by_devt(devt, cmd->filter);
if (!dev && fallback)
dev = dev_cache_get_by_devt(fallback, cmd->filter);
if (!dev) {
log_warn("WARNING: Device for PV %s not found or rejected by a filter.", pvid_txt);
return 0;
}
if (!pvid_txt || !id_read_format(&pvid, pvid_txt)) {
log_error("Missing or ill-formatted PVID for PV: %s.", pvid_txt);
return 0;
}
if (vgid_txt) {
if (!id_read_format(&vgid, vgid_txt))
return_0;
} else
strcpy((char*)&vgid, fmt->orphan_vg_name);
if (!vgname)
vgname = fmt->orphan_vg_name;
if (!(info = lvmcache_add(fmt->labeller, (const char *)&pvid, dev,
vgname, (const char *)&vgid, 0)))
return_0;
lvmcache_get_label(info)->sector = label_sector;
lvmcache_get_label(info)->dev = dev;
lvmcache_set_device_size(info, devsize);
lvmcache_del_das(info);
lvmcache_del_mdas(info);
lvmcache_del_bas(info);
do {
sprintf(mda_id, "mda%d", i);
mda = dm_config_find_node(cn->child, mda_id);
if (mda)
_read_mda(info, fmt, mda);
++i;
} while (mda);
i = 0;
do {
sprintf(da_id, "da%d", i);
da = dm_config_find_node(cn->child, da_id);
if (da) {
if (!dm_config_get_uint64(da->child, "offset", &offset)) return_0;
if (!dm_config_get_uint64(da->child, "size", &size)) return_0;
lvmcache_add_da(info, offset, size);
}
++i;
} while (da);
i = 0;
do {
sprintf(da_id, "ba%d", i);
da = dm_config_find_node(cn->child, da_id);
if (da) {
if (!dm_config_get_uint64(da->child, "offset", &offset)) return_0;
if (!dm_config_get_uint64(da->child, "size", &size)) return_0;
lvmcache_add_ba(info, offset, size);
}
++i;
} while (da);
if (alt_devices)
alt_device = alt_devices->v;
while (alt_device) {
dev_alternate = dev_cache_get_by_devt(alt_device->v.i, cmd->filter);
if (dev_alternate) {
if ((info_alternate = lvmcache_add(fmt->labeller, (const char *)&pvid, dev_alternate,
vgname, (const char *)&vgid, 0))) {
dev_alternate_cache = dev_alternate;
info = info_alternate;
lvmcache_get_label(info)->dev = dev_alternate;
}
} else {
log_warn("Duplicate of PV %s dev %s exists on unknown device %"PRId64 ":%" PRId64,
pvid_txt, dev_name(dev), MAJOR(alt_device->v.i), MINOR(alt_device->v.i));
}
alt_device = alt_device->next;
}
/*
* Update lvmcache with the info about the alternate device by
* reading its label, which should update lvmcache.
*/
if (dev_alternate_cache) {
if (!label_read(dev_alternate_cache, &label, 0)) {
log_warn("No PV label found on duplicate device %s.", dev_name(dev_alternate_cache));
}
}
lvmcache_set_preferred_duplicates((const char *)&vgid);
return 1;
}
static int _pv_update_struct_pv(struct physical_volume *pv, struct format_instance *fid)
{
struct lvmcache_info *info;
if ((info = lvmcache_info_from_pvid((const char *)&pv->id, 0))) {
pv->label_sector = lvmcache_get_label(info)->sector;
pv->dev = lvmcache_device(info);
if (!pv->dev)
pv->status |= MISSING_PV;
if (!lvmcache_fid_add_mdas_pv(info, fid))
return_0;
pv->fid = fid;
} else
pv->status |= MISSING_PV; /* probably missing */
return 1;
}
struct volume_group *lvmetad_vg_lookup(struct cmd_context *cmd, const char *vgname, const char *vgid)
{
struct volume_group *vg = NULL;
struct volume_group *vg2 = NULL;
daemon_reply reply;
int found;
char uuid[64];
struct format_instance *fid = NULL;
struct format_instance_ctx fic;
struct dm_config_node *top;
const char *name, *diag_name;
const char *fmt_name;
struct format_type *fmt;
struct dm_config_node *pvcn;
struct pv_list *pvl;
int rescan = 0;
if (!lvmetad_active())
return NULL;
if (vgid) {
if (!id_write_format((const struct id*)vgid, uuid, sizeof(uuid)))
return_NULL;
log_debug_lvmetad("Asking lvmetad for VG %s (%s)", uuid, vgname ? : "name unknown");
reply = _lvmetad_send("vg_lookup", "uuid = %s", uuid, NULL);
diag_name = uuid;
} else {
if (!vgname) {
log_error(INTERNAL_ERROR "VG name required (VGID not available)");
reply = _lvmetad_send("vg_lookup", "name = %s", "MISSING", NULL);
goto out;
}
log_debug_lvmetad("Asking lvmetad for VG %s", vgname);
reply = _lvmetad_send("vg_lookup", "name = %s", vgname, NULL);
diag_name = vgname;
}
if (_lvmetad_handle_reply(reply, "lookup VG", diag_name, &found) && found) {
if (!(top = dm_config_find_node(reply.cft->root, "metadata"))) {
log_error(INTERNAL_ERROR "metadata config node not found.");
goto out;
}
name = daemon_reply_str(reply, "name", NULL);
/* fall back to lvm2 if we don't know better */
fmt_name = dm_config_find_str(top, "metadata/format", "lvm2");
if (!(fmt = get_format_by_name(cmd, fmt_name))) {
log_error(INTERNAL_ERROR
"We do not know the format (%s) reported by lvmetad.",
fmt_name);
goto out;
}
fic.type = FMT_INSTANCE_MDAS | FMT_INSTANCE_AUX_MDAS;
fic.context.vg_ref.vg_name = name;
fic.context.vg_ref.vg_id = vgid;
if (!(fid = fmt->ops->create_instance(fmt, &fic)))
goto_out;
if ((pvcn = dm_config_find_node(top, "metadata/physical_volumes")))
for (pvcn = pvcn->child; pvcn; pvcn = pvcn->sib)
_pv_populate_lvmcache(cmd, pvcn, fmt, 0);
if ((pvcn = dm_config_find_node(top, "metadata/outdated_pvs")))
for (pvcn = pvcn->child; pvcn; pvcn = pvcn->sib)
_pv_populate_lvmcache(cmd, pvcn, fmt, 0);
top->key = name;
if (!(vg = import_vg_from_lvmetad_config_tree(reply.cft, fid)))
goto_out;
/*
* Read the VG from disk, ignoring the lvmetad copy in these
* cases:
*
* 1. The host is not using lvmlockd, but is reading lockd VGs
* using the --shared option. The shared option is meant to
* let hosts not running lvmlockd look at lockd VGs, like the
* foreign option allows hosts to look at foreign VGs. When
* --foreign is used, the code forces a rescan since the local
* lvmetad cache of foreign VGs is likely stale. Similarly,
* for --shared, have the code reading the shared VGs below
* not use the cached copy from lvmetad but to rescan the VG.
*
* 2. The host failed to acquire the VG lock from lvmlockd for
* the lockd VG. In this case, the usual mechanisms for
* updating the lvmetad copy of the VG have been missed. Since
* we don't know if the cached copy is valid, assume it's not.
*
* 3. lvmetad has returned the "vg_invalid" flag, which is the
* usual mechanism used by lvmlockd/lvmetad to cause a host to
* reread a VG from disk that has been modified from another
* host.
*/
if (is_lockd_type(vg->lock_type) && cmd->include_shared_vgs) {
log_debug_lvmetad("Rescan VG %s because including shared", vgname);
rescan = 1;
} else if (is_lockd_type(vg->lock_type) && cmd->lockd_vg_rescan) {
log_debug_lvmetad("Rescan VG %s because no lvmlockd lock is held", vgname);
rescan = 1;
} else if (dm_config_find_node(reply.cft->root, "vg_invalid")) {
log_debug_lvmetad("Rescan VG %s because lvmetad returned invalid", vgname);
rescan = 1;
}
/*
* locking may have detected a newer vg version and
* invalidated the cached vg.
*/
if (rescan) {
log_debug_lvmetad("Update invalid lvmetad cache for VG %s", vgname);
vg2 = lvmetad_pvscan_vg(cmd, vg);
release_vg(vg);
vg = vg2;
if (!vg) {
log_debug_lvmetad("VG %s from lvmetad not found during rescan.", vgname);
fid = NULL;
goto out;
} else
fid = vg->fid;
}
dm_list_iterate_items(pvl, &vg->pvs) {
if (!_pv_update_struct_pv(pvl->pv, fid)) {
vg = NULL;
goto_out; /* FIXME error path */
}
}
dm_list_iterate_items(pvl, &vg->pvs_outdated) {
if (!_pv_update_struct_pv(pvl->pv, fid)) {
vg = NULL;
goto_out; /* FIXME error path */
}
}
lvmcache_update_vg(vg, 0);
vg_mark_partial_lvs(vg, 1);
}
out:
if (!vg && fid)
fid->fmt->ops->destroy_instance(fid);
daemon_reply_destroy(reply);
return vg;
}
struct _fixup_baton {
int i;
int find;
int ignore;
};
static int _fixup_ignored(struct metadata_area *mda, void *baton) {
struct _fixup_baton *b = baton;
if (b->i == b->find)
mda_set_ignored(mda, b->ignore);
b->i ++;
return 1;
}
int lvmetad_vg_update(struct volume_group *vg)
{
daemon_reply reply;
struct dm_hash_node *n;
struct metadata_area *mda;
char mda_id[128], *num;
struct pv_list *pvl;
struct lvmcache_info *info;
struct _fixup_baton baton;
if (!vg)
return 0;
if (!lvmetad_active() || test_mode())
return 1; /* fake it */
if (!vg->cft_precommitted) {
log_error(INTERNAL_ERROR "VG update without precommited");
return 0;
}
log_debug_lvmetad("Sending lvmetad updated metadata for VG %s (seqno %" PRIu32 ")", vg->name, vg->seqno);
reply = _lvmetad_send("vg_update", "vgname = %s", vg->name,
"metadata = %t", vg->cft_precommitted, NULL);
if (!_lvmetad_handle_reply(reply, "update VG", vg->name, NULL)) {
daemon_reply_destroy(reply);
return 0;
}
daemon_reply_destroy(reply);
n = (vg->fid && vg->fid->metadata_areas_index) ?
dm_hash_get_first(vg->fid->metadata_areas_index) : NULL;
while (n) {
mda = dm_hash_get_data(vg->fid->metadata_areas_index, n);
strcpy(mda_id, dm_hash_get_key(vg->fid->metadata_areas_index, n));
if ((num = strchr(mda_id, '_'))) {
*num = 0;
++num;
if ((info = lvmcache_info_from_pvid(mda_id, 0))) {
memset(&baton, 0, sizeof(baton));
baton.find = atoi(num);
baton.ignore = mda_is_ignored(mda);
lvmcache_foreach_mda(info, _fixup_ignored, &baton);
}
}
n = dm_hash_get_next(vg->fid->metadata_areas_index, n);
}
dm_list_iterate_items(pvl, &vg->pvs) {
/* NB. the PV fmt pointer is sometimes wrong during vgconvert */
if (pvl->pv->dev && !lvmetad_pv_found(&pvl->pv->id, pvl->pv->dev,
vg->fid ? vg->fid->fmt : pvl->pv->fmt,
pvl->pv->label_sector, NULL, NULL))
return 0;
}
return 1;
}
int lvmetad_vg_remove(struct volume_group *vg)
{
char uuid[64];
daemon_reply reply;
int result;
if (!lvmetad_active() || test_mode())
return 1; /* just fake it */
if (!id_write_format(&vg->id, uuid, sizeof(uuid)))
return_0;
log_debug_lvmetad("Telling lvmetad to remove VGID %s (%s)", uuid, vg->name);
reply = _lvmetad_send("vg_remove", "uuid = %s", uuid, NULL);
result = _lvmetad_handle_reply(reply, "remove VG", vg->name, NULL);
daemon_reply_destroy(reply);
return result;
}
int lvmetad_pv_lookup(struct cmd_context *cmd, struct id pvid, int *found)
{
char uuid[64];
daemon_reply reply;
int result = 0;
struct dm_config_node *cn;
if (!lvmetad_active())
return_0;
if (!id_write_format(&pvid, uuid, sizeof(uuid)))
return_0;
log_debug_lvmetad("Asking lvmetad for PV %s", uuid);
reply = _lvmetad_send("pv_lookup", "uuid = %s", uuid, NULL);
if (!_lvmetad_handle_reply(reply, "lookup PV", "", found))
goto_out;
if (found && !*found)
goto out_success;
if (!(cn = dm_config_find_node(reply.cft->root, "physical_volume")))
goto_out;
else if (!_pv_populate_lvmcache(cmd, cn, NULL, 0))
goto_out;
out_success:
result = 1;
out:
daemon_reply_destroy(reply);
return result;
}
int lvmetad_pv_lookup_by_dev(struct cmd_context *cmd, struct device *dev, int *found)
{
int result = 0;
daemon_reply reply;
struct dm_config_node *cn;
if (!lvmetad_active())
return_0;
log_debug_lvmetad("Asking lvmetad for PV on %s", dev_name(dev));
reply = _lvmetad_send("pv_lookup", "device = %" PRId64, (int64_t) dev->dev, NULL);
if (!_lvmetad_handle_reply(reply, "lookup PV", dev_name(dev), found))
goto_out;
if (found && !*found)
goto out_success;
cn = dm_config_find_node(reply.cft->root, "physical_volume");
if (!cn || !_pv_populate_lvmcache(cmd, cn, NULL, dev->dev))
goto_out;
out_success:
result = 1;
out:
daemon_reply_destroy(reply);
return result;
}
int lvmetad_pv_list_to_lvmcache(struct cmd_context *cmd)
{
daemon_reply reply;
struct dm_config_node *cn;
if (!lvmetad_active())
return 1;
log_debug_lvmetad("Asking lvmetad for complete list of known PVs");
reply = _lvmetad_send("pv_list", NULL);
if (!_lvmetad_handle_reply(reply, "list PVs", "", NULL)) {
daemon_reply_destroy(reply);
return_0;
}
if ((cn = dm_config_find_node(reply.cft->root, "physical_volumes")))
for (cn = cn->child; cn; cn = cn->sib)
_pv_populate_lvmcache(cmd, cn, NULL, 0);
daemon_reply_destroy(reply);
return 1;
}
int lvmetad_get_vgnameids(struct cmd_context *cmd, struct dm_list *vgnameids)
{
struct vgnameid_list *vgnl;
struct id vgid;
const char *vgid_txt;
const char *vg_name;
daemon_reply reply;
struct dm_config_node *cn;
log_debug_lvmetad("Asking lvmetad for complete list of known VG ids/names");
reply = _lvmetad_send("vg_list", NULL);
if (!_lvmetad_handle_reply(reply, "list VGs", "", NULL)) {
daemon_reply_destroy(reply);
return_0;
}
if ((cn = dm_config_find_node(reply.cft->root, "volume_groups"))) {
for (cn = cn->child; cn; cn = cn->sib) {
vgid_txt = cn->key;
if (!id_read_format(&vgid, vgid_txt)) {
stack;
continue;
}
if (!(vgnl = dm_pool_alloc(cmd->mem, sizeof(*vgnl)))) {
log_error("vgnameid_list allocation failed.");
return 0;
}
if (!(vg_name = dm_config_find_str(cn->child, "name", NULL))) {
log_error("vg_list no name found.");
return 0;
}
vgnl->vgid = dm_pool_strdup(cmd->mem, (char *)&vgid);
vgnl->vg_name = dm_pool_strdup(cmd->mem, vg_name);
if (!vgnl->vgid || !vgnl->vg_name) {
log_error("vgnameid_list member allocation failed.");
return 0;
}
dm_list_add(vgnameids, &vgnl->list);
}
}
daemon_reply_destroy(reply);
return 1;
}
int lvmetad_vg_list_to_lvmcache(struct cmd_context *cmd)
{
struct volume_group *tmp;
struct id vgid;
const char *vgid_txt;
daemon_reply reply;
struct dm_config_node *cn;
if (!lvmetad_active())
return 1;
log_debug_lvmetad("Asking lvmetad for complete list of known VGs");
reply = _lvmetad_send("vg_list", NULL);
if (!_lvmetad_handle_reply(reply, "list VGs", "", NULL)) {
daemon_reply_destroy(reply);
return_0;
}
if ((cn = dm_config_find_node(reply.cft->root, "volume_groups")))
for (cn = cn->child; cn; cn = cn->sib) {
vgid_txt = cn->key;
if (!id_read_format(&vgid, vgid_txt)) {
stack;
continue;
}
/* the call to lvmetad_vg_lookup will poke the VG into lvmcache */
tmp = lvmetad_vg_lookup(cmd, NULL, (const char*)&vgid);
release_vg(tmp);
}
daemon_reply_destroy(reply);
return 1;
}
struct _extract_dl_baton {
int i;
struct dm_config_tree *cft;
struct dm_config_node *pre_sib;
};
static int _extract_mda(struct metadata_area *mda, void *baton)
{
struct _extract_dl_baton *b = baton;
struct dm_config_node *cn;
char id[32];
if (!mda->ops->mda_export_text) /* do nothing */
return 1;
(void) dm_snprintf(id, 32, "mda%d", b->i);
if (!(cn = make_config_node(b->cft, id, b->cft->root, b->pre_sib)))
return 0;
if (!mda->ops->mda_export_text(mda, b->cft, cn))
return 0;
b->i ++;
b->pre_sib = cn; /* for efficiency */
return 1;
}
static int _extract_disk_location(const char *name, struct disk_locn *dl, void *baton)
{
struct _extract_dl_baton *b = baton;
struct dm_config_node *cn;
char id[32];
if (!dl)
return 1;
(void) dm_snprintf(id, 32, "%s%d", name, b->i);
if (!(cn = make_config_node(b->cft, id, b->cft->root, b->pre_sib)))
return 0;
if (!config_make_nodes(b->cft, cn, NULL,
"offset = %"PRId64, (int64_t) dl->offset,
"size = %"PRId64, (int64_t) dl->size,
NULL))
return 0;
b->i ++;
b->pre_sib = cn; /* for efficiency */
return 1;
}
static int _extract_da(struct disk_locn *da, void *baton)
{
return _extract_disk_location("da", da, baton);
}
static int _extract_ba(struct disk_locn *ba, void *baton)
{
return _extract_disk_location("ba", ba, baton);
}
static int _extract_mdas(struct lvmcache_info *info, struct dm_config_tree *cft,
struct dm_config_node *pre_sib)
{
struct _extract_dl_baton baton = { .i = 0, .cft = cft, .pre_sib = NULL };
if (!lvmcache_foreach_mda(info, &_extract_mda, &baton))
return 0;
baton.i = 0;
if (!lvmcache_foreach_da(info, &_extract_da, &baton))
return 0;
baton.i = 0;
if (!lvmcache_foreach_ba(info, &_extract_ba, &baton))
return 0;
return 1;
}
int lvmetad_pv_found(const struct id *pvid, struct device *dev, const struct format_type *fmt,
uint64_t label_sector, struct volume_group *vg, activation_handler handler)
{
char uuid[64];
daemon_reply reply;
struct lvmcache_info *info;
struct dm_config_tree *pvmeta, *vgmeta;
const char *status, *vgname, *vgid;
int64_t changed;
int result;
if (!lvmetad_active() || test_mode())
return 1;
if (!id_write_format(pvid, uuid, sizeof(uuid)))
return_0;
pvmeta = dm_config_create();
if (!pvmeta)
return_0;
info = lvmcache_info_from_pvid((const char *)pvid, 0);
if (!(pvmeta->root = make_config_node(pvmeta, "pv", NULL, NULL))) {
dm_config_destroy(pvmeta);
return_0;
}
if (!config_make_nodes(pvmeta, pvmeta->root, NULL,
"device = %"PRId64, (int64_t) dev->dev,
"dev_size = %"PRId64, (int64_t) (info ? lvmcache_device_size(info) : 0),
"format = %s", fmt->name,
"label_sector = %"PRId64, (int64_t) label_sector,
"id = %s", uuid,
NULL))
{
dm_config_destroy(pvmeta);
return_0;
}
if (info)
/* FIXME A more direct route would be much preferable. */
_extract_mdas(info, pvmeta, pvmeta->root);
if (vg) {
if (!(vgmeta = export_vg_to_config_tree(vg))) {
dm_config_destroy(pvmeta);
return_0;
}
log_debug_lvmetad("Telling lvmetad to store PV %s (%s) in VG %s", dev_name(dev), uuid, vg->name);
reply = _lvmetad_send("pv_found",
"pvmeta = %t", pvmeta,
"vgname = %s", vg->name,
"metadata = %t", vgmeta,
NULL);
dm_config_destroy(vgmeta);
} else {
/*
* There is no VG metadata stored on this PV.
* It might or might not be an orphan.
*/
log_debug_lvmetad("Telling lvmetad to store PV %s (%s)", dev_name(dev), uuid);
reply = _lvmetad_send("pv_found", "pvmeta = %t", pvmeta, NULL);
}
dm_config_destroy(pvmeta);
result = _lvmetad_handle_reply(reply, "update PV", uuid, NULL);
if (vg && result &&
(daemon_reply_int(reply, "seqno_after", -1) != vg->seqno ||
daemon_reply_int(reply, "seqno_after", -1) != daemon_reply_int(reply, "seqno_before", -1)))
log_warn("WARNING: Inconsistent metadata found for VG %s", vg->name);
/*
* pvscan --cache does not perform any lvmlockd locking, and
* pvscan --cache -aay skips autoactivation in lockd VGs.
*
* pvscan --cache populates lvmetad with VG metadata from disk.
* No lvmlockd locking is needed. It is expected that lockd VG
* metadata that is read by pvscan and populated in lvmetad may
* be immediately stale due to changes to the VG from other hosts
* during or after this pvscan. This is normal and not a problem.
* When a subsequent lvm command uses the VG, it will lock the VG
* with lvmlockd, read the VG from lvmetad, and update the cached
* copy from disk if necessary.
*
* pvscan --cache -aay does not activate LVs in lockd VGs because
* activation requires locking, and a lock-start operation is needed
* on a lockd VG before any locking can be performed in it.
*
* An equivalent of pvscan --cache -aay for lockd VGs is:
* 1. pvscan --cache
* 2. vgchange --lock-start
* 3. vgchange -aay -S 'locktype=sanlock || locktype=dlm'
*
* [We could eventually add support for autoactivating lockd VGs
* using pvscan by incorporating the lock start step (which can
* take a long time), but there may be a better option than
* continuing to overload pvscan.]
*
* Stages of starting a lockd VG:
*
* . pvscan --cache populates lockd VGs in lvmetad without locks,
* and this initial cached copy may quickly become stale.
*
* . vgchange --lock-start VG reads the VG without the VG lock
* because no locks are available until the locking is started.
* It only uses the VG name and lock_type from the VG metadata,
* and then only uses it to start the VG lockspace in lvmlockd.
*
* . Further lvm commands, e.g. activation, can then lock the VG
* with lvmlockd and use current VG metdata.
*/
if (handler && vg && is_lockd_type(vg->lock_type)) {
log_debug_lvmetad("Skip pvscan activation for lockd type VG %s", vg->name);
handler = NULL;
}
if (result && handler) {
status = daemon_reply_str(reply, "status", "<missing>");
vgname = daemon_reply_str(reply, "vgname", "<missing>");
vgid = daemon_reply_str(reply, "vgid", "<missing>");
changed = daemon_reply_int(reply, "changed", 0);
if (!strcmp(status, "partial"))
handler(_lvmetad_cmd, vgname, vgid, 1, changed, CHANGE_AAY);
else if (!strcmp(status, "complete"))
handler(_lvmetad_cmd, vgname, vgid, 0, changed, CHANGE_AAY);
else if (!strcmp(status, "orphan"))
;
else
log_error("Request to %s %s in lvmetad gave status %s.",
"update PV", uuid, status);
}
daemon_reply_destroy(reply);
return result;
}
int lvmetad_pv_gone(dev_t devno, const char *pv_name, activation_handler handler)
{
daemon_reply reply;
int result;
int found;
if (!lvmetad_active() || test_mode())
return 1;
/*
* TODO: automatic volume deactivation takes place here *before*
* all cached info is gone - call handler. Also, consider
* integrating existing deactivation script that deactivates
* the whole stack from top to bottom (not yet upstream).
*/
log_debug_lvmetad("Telling lvmetad to forget any PV on %s", pv_name);
reply = _lvmetad_send("pv_gone", "device = %" PRId64, (int64_t) devno, NULL);
result = _lvmetad_handle_reply(reply, "drop PV", pv_name, &found);
/* We don't care whether or not the daemon had the PV cached. */
daemon_reply_destroy(reply);
return result;
}
int lvmetad_pv_gone_by_dev(struct device *dev, activation_handler handler)
{
return lvmetad_pv_gone(dev->dev, dev_name(dev), handler);
}
/*
* The following code implements pvscan --cache.
*/
struct _lvmetad_pvscan_baton {
struct volume_group *vg;
struct format_instance *fid;
};
static int _lvmetad_pvscan_single(struct metadata_area *mda, void *baton)
{
struct _lvmetad_pvscan_baton *b = baton;
struct volume_group *this;
if (!(this = mda_is_ignored(mda) ? NULL : mda->ops->vg_read(b->fid, "", mda, NULL, NULL, 1)))
return 1;
/* FIXME Also ensure contents match etc. */
if (!b->vg || this->seqno > b->vg->seqno)
b->vg = this;
else if (b->vg)
release_vg(this);
return 1;
}
/*
* The lock manager may detect that the vg cached in lvmetad is out of date,
* due to something like an lvcreate from another host.
* This is limited to changes that only affect the vg (not global state like
* orphan PVs), so we only need to reread mdas on the vg's existing pvs.
*/
static struct volume_group *lvmetad_pvscan_vg(struct cmd_context *cmd, struct volume_group *vg)
{
struct volume_group *vg_ret = NULL;
struct dm_config_tree *vgmeta_ret = NULL;
struct dm_config_tree *vgmeta;
struct pv_list *pvl;
struct lvmcache_info *info;
struct format_instance *fid;
struct format_instance_ctx fic = { .type = 0 };
struct _lvmetad_pvscan_baton baton;
dm_list_iterate_items(pvl, &vg->pvs) {
/* missing pv */
if (!pvl->pv->dev)
continue;
if (!(info = lvmcache_info_from_pvid((const char *)&pvl->pv->id, 0))) {
log_error("Failed to find cached info for PV %s.", pv_dev_name(pvl->pv));
return NULL;
}
baton.vg = NULL;
baton.fid = lvmcache_fmt(info)->ops->create_instance(lvmcache_fmt(info), &fic);
if (!baton.fid)
return NULL;
if (baton.fid->fmt->features & FMT_OBSOLETE) {
log_error("WARNING: Ignoring obsolete format of metadata (%s) on device %s when using lvmetad",
baton.fid->fmt->name, dev_name(pvl->pv->dev));
lvmcache_fmt(info)->ops->destroy_instance(baton.fid);
return NULL;
}
lvmcache_foreach_mda(info, _lvmetad_pvscan_single, &baton);
if (!baton.vg) {
lvmcache_fmt(info)->ops->destroy_instance(baton.fid);
return NULL;
}
if (!(vgmeta = export_vg_to_config_tree(baton.vg))) {
log_error("VG export to config tree failed");
release_vg(baton.vg);
return NULL;
}
if (!vgmeta_ret) {
vgmeta_ret = vgmeta;
} else {
if (!compare_config(vgmeta_ret->root, vgmeta->root)) {
log_error("VG metadata comparison failed");
dm_config_destroy(vgmeta);
dm_config_destroy(vgmeta_ret);
release_vg(baton.vg);
return NULL;
}
dm_config_destroy(vgmeta);
}
release_vg(baton.vg);
}
if (vgmeta_ret) {
fid = lvmcache_fmt(info)->ops->create_instance(lvmcache_fmt(info), &fic);
if (!(vg_ret = import_vg_from_config_tree(vgmeta_ret, fid))) {
log_error("VG import from config tree failed");
lvmcache_fmt(info)->ops->destroy_instance(fid);
goto out;
}
/*
* Update lvmetad with the newly read version of the VG.
* The "precommitted" name is a misnomer in this case,
* but that is the field which lvmetad_vg_update() uses
* to send the metadata cft to lvmetad.
*/
vg_ret->cft_precommitted = vgmeta_ret;
if (!lvmetad_vg_update(vg_ret))
log_error("Failed to update lvmetad with new VG meta");
vg_ret->cft_precommitted = NULL;
dm_config_destroy(vgmeta_ret);
}
out:
return vg_ret;
}
int lvmetad_pvscan_single(struct cmd_context *cmd, struct device *dev,
activation_handler handler, int ignore_obsolete)
{
struct label *label;
struct lvmcache_info *info;
struct _lvmetad_pvscan_baton baton;
/* Create a dummy instance. */
struct format_instance_ctx fic = { .type = 0 };
if (!lvmetad_active()) {
log_error("Cannot proceed since lvmetad is not active.");
return 0;
}
if (!label_read(dev, &label, 0)) {
log_print_unless_silent("No PV label found on %s.", dev_name(dev));
if (!lvmetad_pv_gone_by_dev(dev, handler))
goto_bad;
return 1;
}
info = (struct lvmcache_info *) label->info;
baton.vg = NULL;
baton.fid = lvmcache_fmt(info)->ops->create_instance(lvmcache_fmt(info), &fic);
if (!baton.fid)
goto_bad;
if (baton.fid->fmt->features & FMT_OBSOLETE) {
if (ignore_obsolete)
log_warn("WARNING: Ignoring obsolete format of metadata (%s) on device %s when using lvmetad",
baton.fid->fmt->name, dev_name(dev));
else
log_error("WARNING: Ignoring obsolete format of metadata (%s) on device %s when using lvmetad",
baton.fid->fmt->name, dev_name(dev));
lvmcache_fmt(info)->ops->destroy_instance(baton.fid);
if (ignore_obsolete)
return 1;
return 0;
}
lvmcache_foreach_mda(info, _lvmetad_pvscan_single, &baton);
/*
* LVM1 VGs have no MDAs and lvmcache_foreach_mda isn't worth fixing
* to use pseudo-mdas for PVs.
* Note that the single_device parameter also gets ignored and this code
* can scan further devices.
*/
if (!baton.vg && !(baton.fid->fmt->features & FMT_MDAS))
baton.vg = ((struct metadata_area *) dm_list_first(&baton.fid->metadata_areas_in_use))->ops->vg_read(baton.fid, lvmcache_vgname_from_info(info), NULL, NULL, NULL, 1);
if (!baton.vg)
lvmcache_fmt(info)->ops->destroy_instance(baton.fid);
/*
* NB. If this command failed and we are relying on lvmetad to have an
* *exact* image of the system, the lvmetad instance that went out of
* sync needs to be killed.
*/
if (!lvmetad_pv_found((const struct id *) &dev->pvid, dev, lvmcache_fmt(info),
label->sector, baton.vg, handler)) {
release_vg(baton.vg);
goto_bad;
}
release_vg(baton.vg);
return 1;
bad:
/* FIXME kill lvmetad automatically if we can */
log_error("Update of lvmetad failed. This is a serious problem.\n "
"It is strongly recommended that you restart lvmetad immediately.");
return 0;
}
static int _lvmetad_pvscan_all_devs(struct cmd_context *cmd, activation_handler handler,
int ignore_obsolete)
{
struct dev_iter *iter;
struct device *dev;
daemon_reply reply;
int r = 1;
char *future_token;
int was_silent;
if (!lvmetad_active()) {
log_error("Cannot proceed since lvmetad is not active.");
return 0;
}
if (!(iter = dev_iter_create(cmd->lvmetad_filter, 1))) {
log_error("dev_iter creation failed");
return 0;
}
future_token = _lvmetad_token;
_lvmetad_token = (char *) "update in progress";
if (!_token_update()) {
dev_iter_destroy(iter);
_lvmetad_token = future_token;
return 0;
}
log_debug_lvmetad("Telling lvmetad to clear its cache");
reply = _lvmetad_send("pv_clear_all", NULL);
if (!_lvmetad_handle_reply(reply, "clear info about all PVs", "", NULL))
r = 0;
daemon_reply_destroy(reply);
was_silent = silent_mode();
init_silent(1);
while ((dev = dev_iter_get(iter))) {
if (sigint_caught()) {
r = 0;
stack;
break;
}
if (!lvmetad_pvscan_single(cmd, dev, handler, ignore_obsolete))
r = 0;
}
init_silent(was_silent);
dev_iter_destroy(iter);
_lvmetad_token = future_token;
if (!_token_update())
return 0;
return r;
}
int lvmetad_pvscan_all_devs(struct cmd_context *cmd, activation_handler handler)
{
return _lvmetad_pvscan_all_devs(cmd, handler, 0);
}
/*
* FIXME Implement this function, skipping PVs known to belong to local or clustered,
* non-exported VGs.
*/
int lvmetad_pvscan_foreign_vgs(struct cmd_context *cmd, activation_handler handler)
{
return _lvmetad_pvscan_all_devs(cmd, handler, 1);
}
int lvmetad_vg_clear_outdated_pvs(struct volume_group *vg)
{
char uuid[64];
daemon_reply reply;
int result;
if (!id_write_format(&vg->id, uuid, sizeof(uuid)))
return_0;
reply = _lvmetad_send("vg_clear_outdated_pvs", "vgid = %s", uuid, NULL);
result = _lvmetad_handle_reply(reply, "clear the list of outdated PVs", vg->name, NULL);
daemon_reply_destroy(reply);
return result;
}
/*
* Records the state of cached PVs in lvmetad so we can look for changes
* after rescanning.
*/
struct pv_cache_list {
struct dm_list list;
dev_t devt;
struct id pvid;
const char *vgid;
unsigned found : 1;
unsigned update_udev : 1;
};
/*
* Get the list of PVs known to lvmetad.
*/
static int _lvmetad_get_pv_cache_list(struct cmd_context *cmd, struct dm_list *pvc_list)
{
daemon_reply reply;
struct dm_config_node *cn;
struct pv_cache_list *pvcl;
const char *pvid_txt;
const char *vgid;
if (!lvmetad_active())
return 1;
log_debug_lvmetad("Asking lvmetad for complete list of known PVs");
reply = _lvmetad_send("pv_list", NULL);
if (!_lvmetad_handle_reply(reply, "list PVs", "", NULL)) {
log_error("lvmetad message failed.");
daemon_reply_destroy(reply);
return_0;
}
if ((cn = dm_config_find_node(reply.cft->root, "physical_volumes"))) {
for (cn = cn->child; cn; cn = cn->sib) {
if (!(pvcl = dm_pool_zalloc(cmd->mem, sizeof(*pvcl)))) {
log_error("pv_cache_list allocation failed.");
return 0;
}
pvid_txt = cn->key;
if (!id_read_format(&pvcl->pvid, pvid_txt)) {
stack;
continue;
}
pvcl->devt = dm_config_find_int(cn->child, "device", 0);
if ((vgid = dm_config_find_str(cn->child, "vgid", NULL)))
pvcl->vgid = dm_pool_strdup(cmd->mem, vgid);
dm_list_add(pvc_list, &pvcl->list);
}
}
daemon_reply_destroy(reply);
return 1;
}
/*
* Opening the device RDWR should trigger a udev db update.
* FIXME: is there a better way to update the udev db than
* doing an open/close of the device? - For example writing
* "change" to /sys/block/<device>/uevent?
*/
static void _update_pv_in_udev(struct cmd_context *cmd, dev_t devt)
{
struct device *dev;
log_debug_devs("device %d:%d open to update udev",
(int)MAJOR(devt), (int)MINOR(devt));
if (!(dev = dev_cache_get_by_devt(devt, cmd->lvmetad_filter))) {
log_error("_update_pv_in_udev no dev found");
return;
}
if (!dev_open(dev)) {
stack;
return;
}
if (!dev_close(dev))
stack;
}
/*
* Compare before and after PV lists from before/after rescanning,
* and update udev db for changes.
*
* For PVs that have changed pvid or vgid in lvmetad from rescanning,
* there may be information in the udev database to update, so open
* these devices to trigger a udev update.
*
* "before" refers to the list of pvs from lvmetad before rescanning
* "after" refers to the list of pvs from lvmetad after rescanning
*
* Comparing both lists, we can see which PVs changed (pvid or vgid),
* and trigger a udev db update for those.
*/
static void _update_changed_pvs_in_udev(struct cmd_context *cmd,
struct dm_list *pvc_before,
struct dm_list *pvc_after)
{
struct pv_cache_list *before;
struct pv_cache_list *after;
char id_before[ID_LEN + 1] __attribute__((aligned(8)));
char id_after[ID_LEN + 1] __attribute__((aligned(8)));
int found;
dm_list_iterate_items(before, pvc_before) {
found = 0;
dm_list_iterate_items(after, pvc_after) {
if (after->found)
continue;
if (before->devt != after->devt)
continue;
if (!id_equal(&before->pvid, &after->pvid)) {
memset(id_before, 0, sizeof(id_before));
memset(id_after, 0, sizeof(id_after));
strncpy(&id_before[0], (char *) &before->pvid, sizeof(id_before) - 1);
strncpy(&id_after[0], (char *) &after->pvid, sizeof(id_after) - 1);
log_debug_devs("device %d:%d changed pvid from %s to %s",
(int)MAJOR(before->devt), (int)MINOR(before->devt),
id_before, id_after);
before->update_udev = 1;
} else if ((before->vgid && !after->vgid) ||
(after->vgid && !before->vgid) ||
(before->vgid && after->vgid && strcmp(before->vgid, after->vgid))) {
log_debug_devs("device %d:%d changed vg from %s to %s",
(int)MAJOR(before->devt), (int)MINOR(before->devt),
before->vgid ?: "none", after->vgid ?: "none");
before->update_udev = 1;
}
after->found = 1;
before->found = 1;
found = 1;
break;
}
if (!found) {
memset(id_before, 0, sizeof(id_before));
strncpy(&id_before[0], (char *) &before->pvid, sizeof(id_before) - 1);
log_debug_devs("device %d:%d pvid %s vg %s is gone",
(int)MAJOR(before->devt), (int)MINOR(before->devt),
id_before, before->vgid ? before->vgid : "none");
before->update_udev = 1;
}
}
dm_list_iterate_items(before, pvc_before) {
if (before->update_udev)
_update_pv_in_udev(cmd, before->devt);
}
dm_list_iterate_items(after, pvc_after) {
if (after->update_udev)
_update_pv_in_udev(cmd, after->devt);
}
}
/*
* Before this command was run, some external entity may have
* invalidated lvmetad's cache of global information, e.g. lvmlockd.
*
* The global information includes things like a new VG, a
* VG that was removed, the assignment of a PV to a VG;
* any change that is not isolated within a single VG.
*
* The external entity, like a lock manager, would invalidate
* the lvmetad global cache if it detected that the global
* information had been changed on disk by something other
* than a local lvm command, e.g. an lvm command on another
* host with access to the same devices. (How it detects
* the change is specific to lock manager or other entity.)
*
* The effect is that metadata on disk is newer than the metadata
* in the local lvmetad daemon, and the local lvmetad's cache
* should be updated from disk before this command uses it.
*
* So, using this function, a command checks if lvmetad's global
* cache is valid. If so, it does nothing. If not, it rescans
* devices to update the lvmetad cache, then it notifies lvmetad
* that it's cache is valid again (consistent with what's on disk.)
* This command can then go ahead and use the newly refreshed metadata.
*
* 1. Check if the lvmetad global cache is invalid.
* 2. If so, reread metadata from all devices and update the lvmetad cache.
* 3. Tell lvmetad that the global cache is now valid.
*/
void lvmetad_validate_global_cache(struct cmd_context *cmd, int force)
{
struct dm_list pvc_before; /* pv_cache_list */
struct dm_list pvc_after; /* pv_cache_list */
daemon_reply reply;
int global_invalid;
dm_list_init(&pvc_before);
dm_list_init(&pvc_after);
if (!lvmlockd_use()) {
log_error(INTERNAL_ERROR "validate global cache without lvmlockd");
return;
}
if (!lvmetad_used())
return;
log_debug_lvmetad("Validating global lvmetad cache");
if (force)
goto do_scan;
reply = daemon_send_simple(_lvmetad, "get_global_info",
"token = %s", "skip",
NULL);
if (reply.error) {
log_error("lvmetad_validate_global_cache get_global_info error %d", reply.error);
goto do_scan;
}
if (strcmp(daemon_reply_str(reply, "response", ""), "OK")) {
log_error("lvmetad_validate_global_cache get_global_info not ok");
goto do_scan;
}
global_invalid = daemon_reply_int(reply, "global_invalid", -1);
daemon_reply_destroy(reply);
if (!global_invalid) {
/* cache is valid */
return;
}
do_scan:
/*
* Save the current state of pvs from lvmetad so after devices are
* scanned, we can compare to the new state to see if pvs changed.
*/
_lvmetad_get_pv_cache_list(cmd, &pvc_before);
/*
* Update the local lvmetad cache so it correctly reflects any
* changes made on remote hosts.
*/
lvmetad_pvscan_all_devs(cmd, NULL);
/*
* Clear the global_invalid flag in lvmetad.
* Subsequent local commands that read global state
* from lvmetad will not see global_invalid until
* another host makes another global change.
*/
reply = daemon_send_simple(_lvmetad, "set_global_info",
"token = %s", "skip",
"global_invalid = %d", 0,
NULL);
if (reply.error)
log_error("lvmetad_validate_global_cache set_global_info error %d", reply.error);
if (strcmp(daemon_reply_str(reply, "response", ""), "OK"))
log_error("lvmetad_validate_global_cache set_global_info not ok");
daemon_reply_destroy(reply);
/*
* Populate this command's lvmcache structures from lvmetad.
*/
lvmcache_seed_infos_from_lvmetad(cmd);
/*
* Update the local udev database to reflect PV changes from
* other hosts.
*
* Compare the before and after PV lists, and if a PV's
* pvid or vgid has changed, then open that device to trigger
* a uevent to update the udev db.
*
* This has no direct benefit to lvm, but is just a best effort
* attempt to keep the udev db updated and reflecting current
* lvm information.
*
* FIXME: lvmcache_seed_infos_from_lvmetad() and _lvmetad_get_pv_cache_list()
* each get pv_list from lvmetad, and they could share a single pv_list reply.
*/
if (!dm_list_empty(&pvc_before)) {
_lvmetad_get_pv_cache_list(cmd, &pvc_after);
_update_changed_pvs_in_udev(cmd, &pvc_before, &pvc_after);
}
}