[linux-lvm] Who can tell me what is the mean of Active in LVM?

[louis_fang]

linux-lvm at redhat.com，:
This is the active.c ,and i want to know what  functions it act?
                      #include "lib.h"
#include "metadata.h"
#include "activate.h"
#include "memlock.h"
#include "display.h"
#include "fs.h"
#include "lvm-string.h"
#include "pool.h"
#include "toolcontext.h"
#include "dev_manager.h"

#include <limits.h>
#include <fcntl.h>
#include <unistd.h>

#define _skip(fmt, args...) log_very_verbose("Skipping: " fmt , ## args)

#ifndef DEVMAPPER_SUPPORT
void set_activation(int act)
{
	if (act)
		log_error("Compiled without libdevmapper support. "
			  "Can't enable activation.");
}
int activation(void)
{
	return 0;
}
int library_version(char *version, size_t size)
{
	return 0;
}
int driver_version(char *version, size_t size)
{
	return 0;
}
int lv_info(const struct logical_volume *lv, struct lvinfo *info)
{
	return 0;
}
int lv_snapshot_percent(struct logical_volume *lv, float *percent)
{
	return 0;
}
int lv_mirror_percent(struct logical_volume *lv, int wait, float *percent,
		      uint32_t *event_nr)
{
	return 0;
}
int lvs_in_vg_activated(struct volume_group *vg)
{
	return 0;
}
int lvs_in_vg_opened(struct volume_group *vg)
{
	return 0;
}
int lv_suspend_if_active(struct cmd_context *cmd, const char *lvid_s)
{
	return 1;
}
int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s)
{
	return 1;
}
int lv_deactivate(struct cmd_context *cmd, const char *lvid_s)
{
	return 1;
}
int lv_activate(struct cmd_context *cmd, const char *lvid_s)
{
	return 1;
}

int lv_mknodes(struct cmd_context *cmd, const struct logical_volume *lv)
{
	return 1;
}

void activation_exit(void)
{
	return;
}

#else				/* DEVMAPPER_SUPPORT */

static int _activation = 1;

void set_activation(int act)
{
	if (act == _activation)
		return;

	_activation = act;
	if (_activation)
		log_verbose("Activation enabled. Device-mapper kernel "
			    "driver will be used.");
	else
		log_verbose("Activation disabled. No device-mapper "
			    "interaction will be attempted.");
}

int activation(void)
{
	return _activation;
}

int library_version(char *version, size_t size)
{
	if (!activation())
		return 0;

	if (!dm_get_library_version(version, size))
		return 0;
	return 1;
}

int driver_version(char *version, size_t size)
{
	int r = 0;
	struct dm_task *dmt;

	if (!activation())
		return 0;

	log_very_verbose("Getting driver version");
	if (!(dmt = dm_task_create(DM_DEVICE_VERSION))) {
		stack;
		return 0;
	}

	if (!dm_task_run(dmt))
		log_error("Failed to get driver version");

	if (!dm_task_get_driver_version(dmt, version, size))
		goto out;

	r = 1;

      out:
	dm_task_destroy(dmt);

	return r;
}

/*
 * Returns 1 if info structure populated, else 0 on failure.
 */
static int _lv_info(const struct logical_volume *lv, int mknodes,
		    struct lvinfo *info)
{
	int r;
	struct dev_manager *dm;
	struct dm_info dminfo;

	if (!activation())
		return 0;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_info(dm, lv, mknodes, &dminfo)))
		stack;

	info->exists = dminfo.exists;
	info->suspended = dminfo.suspended;
	info->open_count = dminfo.open_count;
	info->major = dminfo.major;
	info->minor = dminfo.minor;
	info->read_only = dminfo.read_only;

	dev_manager_destroy(dm);
	return r;
}

int lv_info(const struct logical_volume *lv, struct lvinfo *info)
{
	return _lv_info(lv, 0, info);
}

/*
 * Returns 1 if percent set, else 0 on failure.
 */
int lv_snapshot_percent(struct logical_volume *lv, float *percent)
{
	int r;
	struct dev_manager *dm;

	if (!activation())
		return 0;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_snapshot_percent(dm, lv, percent)))
		stack;

	dev_manager_destroy(dm);

	return r;
}

/* FIXME Merge with snapshot_percent */
int lv_mirror_percent(struct logical_volume *lv, int wait, float *percent,
		      uint32_t *event_nr)
{
	int r;
	struct dev_manager *dm;

	if (!activation())
		return 0;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_mirror_percent(dm, lv, wait, percent, event_nr)))
		stack;

	dev_manager_destroy(dm);

	return r;
}

static int _lv_active(struct logical_volume *lv)
{
	struct lvinfo info;

	if (!lv_info(lv, &info)) {
		stack;
		return -1;
	}

	return info.exists;
}

static int _lv_open_count(struct logical_volume *lv)
{
	struct lvinfo info;

	if (!lv_info(lv, &info)) {
		stack;
		return -1;
	}

	return info.open_count;
}

/* FIXME Need to detect and handle an lv rename */
static int _lv_activate(struct logical_volume *lv)
{
	int r;
	struct dev_manager *dm;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_activate(dm, lv)))
		stack;

	dev_manager_destroy(dm);
	return r;
}

static int _lv_deactivate(struct logical_volume *lv)
{
	int r;
	struct dev_manager *dm;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_deactivate(dm, lv)))
		stack;

	dev_manager_destroy(dm);
	return r;
}

static int _lv_suspend(struct logical_volume *lv)
{
	int r;
	struct dev_manager *dm;

	if (!(dm = dev_manager_create(lv->vg->name, lv->vg->cmd->cf))) {
		stack;
		return 0;
	}

	if (!(r = dev_manager_suspend(dm, lv)))
		stack;

	dev_manager_destroy(dm);
	return r;
}

/*
 * These two functions return the number of LVs in the state,
 * or -1 on error.
 */
int lvs_in_vg_activated(struct volume_group *vg)
{
	struct list *lvh;
	struct logical_volume *lv;
	int count = 0;

	if (!activation())
		return 0;

	list_iterate(lvh, &vg->lvs) {
		lv = list_item(lvh, struct lv_list)->lv;
		count += (_lv_active(lv) == 1);
	}

	return count;
}

int lvs_in_vg_opened(struct volume_group *vg)
{
	struct list *lvh;
	struct logical_volume *lv;
	int count = 0;

	if (!activation())
		return 0;

	list_iterate(lvh, &vg->lvs) {
		lv = list_item(lvh, struct lv_list)->lv;
		count += (_lv_open_count(lv) == 1);
	}

	return count;
}

/* These return success if the device is not active */
int lv_suspend_if_active(struct cmd_context *cmd, const char *lvid_s)
{
	struct logical_volume *lv;
	struct lvinfo info;

	if (!activation())
		return 1;

	if (!(lv = lv_from_lvid(cmd, lvid_s)))
		return 0;

	if (test_mode()) {
		_skip("Suspending '%s'.", lv->name);
		return 1;
	}

	if (!lv_info(lv, &info)) {
		stack;
		return 0;
	}

	if (!info.exists || info.suspended)
		return 1;

	memlock_inc();
	if (!_lv_suspend(lv)) {
		memlock_dec();
		fs_unlock();
		return 0;
	}

	return 1;
}

int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s)
{
	struct logical_volume *lv;
	struct lvinfo info;

	if (!activation())
		return 1;

	if (!(lv = lv_from_lvid(cmd, lvid_s)))
		return 0;

	if (test_mode()) {
		_skip("Resuming '%s'.", lv->name);
		return 1;
	}

	if (!lv_info(lv, &info)) {
		stack;
		return 0;
	}

	if (!info.exists || !info.suspended)
		return 1;

	if (!_lv_activate(lv))
		return 0;

	memlock_dec();
	fs_unlock();

	return 1;
}

int lv_deactivate(struct cmd_context *cmd, const char *lvid_s)
{
	struct logical_volume *lv;
	struct lvinfo info;
	int r;

	if (!activation())
		return 1;

	if (!(lv = lv_from_lvid(cmd, lvid_s)))
		return 0;

	if (test_mode()) {
		_skip("Deactivating '%s'.", lv->name);
		return 1;
	}

	if (!lv_info(lv, &info)) {
		stack;
		return 0;
	}

	if (!info.exists)
		return 1;

	if (info.open_count) {
		log_error("LV %s/%s in use: not removing", lv->vg->name,
			  lv->name);
		return 0;
	}

	memlock_inc();
	r = _lv_deactivate(lv);
	memlock_dec();
	fs_unlock();

	return r;
}

int lv_activate(struct cmd_context *cmd, const char *lvid_s)
{
	struct logical_volume *lv;
	struct lvinfo info;
	int r;

	if (!activation())
		return 1;

	if (!(lv = lv_from_lvid(cmd, lvid_s)))
		return 0;

	if (test_mode()) {
		_skip("Activating '%s'.", lv->name);
		return 1;
	}

	if (!lv_info(lv, &info)) {
		stack;
		return 0;
	}

	if (info.exists && !info.suspended)
		return 1;

	memlock_inc();
	r = _lv_activate(lv);
	memlock_dec();
	fs_unlock();

	return r;
}

int lv_mknodes(struct cmd_context *cmd, const struct logical_volume *lv)
{
	struct lvinfo info;
	int r = 1;

	if (!_lv_info(lv, 1, &info)) {
		stack;
		return 0;
	}

	if (info.exists)
		r = dev_manager_mknodes(lv);
	else
		r = dev_manager_rmnodes(lv);

	fs_unlock();

	return r;
}

void activation_exit(void)
{
	dev_manager_exit();
}
#endif

	

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礼！
 				

　　　　　　　　louis_fang
　　　　　　　　louis_fang at usish.com
　　　　　　　　　　2005-04-29