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lvm2/tools/vgscan.c
David Teigland 9b640c3684 pvscan: use process_each_vg for autoactivate
This refactors the code for autoactivation.  Previously,
as each PV was found, it would be sent to lvmetad, and
the VG would be autoactivated using a non-standard VG
processing function (the "activation_handler") called via
a function pointer from within the lvmetad notification path.

Now, any scanning that the command needs to do (scanning
only the named device args, or scanning all devices when
there are no args), is done first, before any activation
is attempted.  During the scans, the VG names are saved.
After scanning is complete, process_each_vg is used to do
autoactivation of the saved VG names.  This makes pvscan
activation much more similar to activation done with
vgchange or lvchange.

The separate autoactivate phase also means that if lvmetad
is disabled (either before or during the scan), the command
can continue with the activation step by simply not using
lvmetad and reverting to disk scanning to do the
activation.
2016-05-23 11:57:32 -05:00

132 lines
4.4 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "tools.h"
static int vgscan_single(struct cmd_context *cmd, const char *vg_name,
struct volume_group *vg,
struct processing_handle *handle __attribute__((unused)))
{
log_print_unless_silent("Found %svolume group \"%s\" using metadata type %s",
vg_is_exported(vg) ? "exported " : "", vg_name,
vg->fid->fmt->name);
check_current_backup(vg);
return ECMD_PROCESSED;
}
/*
* Two main vgscan cases related to lvmetad usage:
* 1. vgscan
* 2. vgscan --cache
*
* 1. The 'vgscan' command (without --cache) may or may not attempt to
* repopulate the lvmetad cache, and may or may not use the lvmetad
* cache to display VG info:
*
* i. If lvmetad is being used and is in a normal state, then 'vgscan'
* will simply read and display VG info from the lvmetad cache.
*
* ii. If lvmetad is not being used, 'vgscan' will read all devices to
* display the VG info.
*
* iii. If lvmetad is being used, but has been disabled (because of
* duplicate devs or lvm1 metadata), or has a non-matching token
* (because the device filter is different from the device filter last
* used to populate lvmetad), then 'vgscan' will begin by rescanning
* devices to repopulate lvmetad. If lvmetad is enabled after the
* rescan, then 'vgscan' will simply read and display VG info from the
* lvmetad cache (like case i). If lvmetad is disabled after the
* rescan, then 'vgscan' will read all devices to display VG info
* (like case ii).
*
* 2. The 'vgscan --cache' command will always attempt to repopulate
* the lvmetad cache by rescanning all devs (regardless of whether
* lvmetad was previously disabled or had an unmatching token.)
* lvmetad may be enabled or disabled after the rescan (depending
* on whether duplicate devs or lvm1 metadata was found).
* If enabled, then it will simply read and display VG info from the
* lvmetad cache (like case 1.i.). If disabled, then it will
* read all devices to display VG info (like case 1.ii.)
*/
int vgscan(struct cmd_context *cmd, int argc, char **argv)
{
const char *reason = NULL;
int maxret, ret;
if (argc) {
log_error("Too many parameters on command line");
return EINVALID_CMD_LINE;
}
if (arg_is_set(cmd, notifydbus_ARG)) {
if (!lvmnotify_is_supported()) {
log_error("Cannot notify dbus: lvm is not built with dbus support.");
return ECMD_FAILED;
}
if (!find_config_tree_bool(cmd, global_notify_dbus_CFG, NULL)) {
log_error("Cannot notify dbus: notify_dbus is disabled in lvm config.");
return ECMD_FAILED;
}
set_pv_notify(cmd);
set_vg_notify(cmd);
set_lv_notify(cmd);
return ECMD_PROCESSED;
}
if (!lock_vol(cmd, VG_GLOBAL, LCK_VG_WRITE, NULL)) {
log_error("Unable to obtain global lock.");
return ECMD_FAILED;
}
if (cmd->filter->wipe)
cmd->filter->wipe(cmd->filter);
lvmcache_destroy(cmd, 1, 0);
if (!lvmetad_used() && arg_is_set(cmd, cache_long_ARG))
log_verbose("Ignoring vgscan --cache command because lvmetad is not in use.");
if (lvmetad_used() && (arg_is_set(cmd, cache_long_ARG) || !lvmetad_token_matches(cmd) || lvmetad_is_disabled(cmd, &reason))) {
if (lvmetad_used() && !lvmetad_pvscan_all_devs(cmd, arg_is_set(cmd, cache_long_ARG))) {
log_warn("WARNING: Not using lvmetad because cache update failed.");
lvmetad_make_unused(cmd);
}
if (lvmetad_used() && lvmetad_is_disabled(cmd, &reason)) {
log_warn("WARNING: Not using lvmetad because %s.", reason);
lvmetad_make_unused(cmd);
}
}
if (!lvmetad_used())
log_print_unless_silent("Reading all physical volumes. This may take a while...");
else
log_print_unless_silent("Reading volume groups from cache.");
maxret = process_each_vg(cmd, argc, argv, NULL, NULL, 0, NULL,
&vgscan_single);
if (arg_count(cmd, mknodes_ARG)) {
ret = vgmknodes(cmd, argc, argv);
if (ret > maxret)
maxret = ret;
}
unlock_vg(cmd, VG_GLOBAL);
return maxret;
}