lvm2/lib/format_text/import.c

/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2008 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "lib.h"
#include "metadata.h"
#include "import-export.h"

/* FIXME Use tidier inclusion method */
static struct text_vg_version_ops *(_text_vsn_list[2]);

static int _text_import_initialised = 0;

static void _init_text_import(void)
{
	if (_text_import_initialised)
		return;

	_text_vsn_list[0] = text_vg_vsn1_init();
	_text_vsn_list[1] = NULL;
	_text_import_initialised = 1;
}

/*
 * Find out vgname on a given device.
 * If the checksum and metadata size is matching the vgname discovered in last read
 * (multi PVs VG) could be passed back and it may skip parsing of such metadata.
 */
const char *text_vgname_import(const struct format_type *fmt,
			       struct device *dev,
			       off_t offset, uint32_t size,
			       off_t offset2, uint32_t size2,
			       checksum_fn_t checksum_fn, uint32_t checksum,
			       const char *vgname,
			       struct id *vgid, uint64_t *vgstatus,
			       char **creation_host)
{
	struct dm_config_tree *cft;
	struct text_vg_version_ops **vsn;

	_init_text_import();

	if (!(cft = config_open(CONFIG_FILE_SPECIAL, NULL, 0)))
		return_NULL;

	if ((!dev && !config_file_read(cft)) ||
	    (dev && !config_file_read_fd(cft, dev, offset, size,
					 offset2, size2, checksum_fn, checksum,
					 (vgname != NULL)))) {
		log_error("Couldn't read volume group metadata.");
		goto out;
	}

	if (vgname)
		goto out; /* Everything is matching from the last call */

	/*
	 * Find a set of version functions that can read this file
	 */
	for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
		if (!(*vsn)->check_version(cft))
			continue;

		if (!(vgname = (*vsn)->read_vgname(fmt, cft, vgid, vgstatus,
						   creation_host)))
			goto_out;

		break;
	}

      out:
	config_destroy(cft);
	return vgname;
}

struct volume_group *text_vg_import_fd(struct format_instance *fid,
				       const char *file,
				       int single_device,
				       struct device *dev,
				       off_t offset, uint32_t size,
				       off_t offset2, uint32_t size2,
				       checksum_fn_t checksum_fn,
				       uint32_t checksum,
				       time_t *when, char **desc)
{
	struct volume_group *vg = NULL;
	struct dm_config_tree *cft;
	struct text_vg_version_ops **vsn;
	int skip_parse;

	_init_text_import();

	*desc = NULL;
	*when = 0;

	if (!(cft = config_open(CONFIG_FILE_SPECIAL, file, 0)))
		return_NULL;

	skip_parse = fid->vg && (fid->mda_checksum == checksum) &&
		(fid->mda_size == (size + size2));

	if ((!dev && !config_file_read(cft)) ||
	    (dev && !config_file_read_fd(cft, dev, offset, size,
					 offset2, size2, checksum_fn, checksum,
					 skip_parse)))
		goto_out;

	if (skip_parse) {
		vg = fid->vg;
		goto out;
	}

	/*
	 * Find a set of version functions that can read this file
	 */
	for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
		if (!(*vsn)->check_version(cft))
			continue;

		if (!(vg = (*vsn)->read_vg(fid, cft, single_device)))
			goto_out;

		(*vsn)->read_desc(vg->vgmem, cft, when, desc);
		break;
	}

	if (vg && (!fid->vg || (vg->seqno > fid->vg->seqno))) {
		/*
		 * Remember vg pointer to newest VG for reuse.
		 * NOTE: _vg_read() will not release same VG
		 */
		fid->vg = vg;
		fid->mda_size = (size + size2);
		fid->mda_checksum = checksum;
	}

      out:
	config_destroy(cft);
	return vg;
}

struct volume_group *text_vg_import_file(struct format_instance *fid,
					 const char *file,
					 time_t *when, char **desc)
{
	return text_vg_import_fd(fid, file, 0, NULL, (off_t)0, 0, (off_t)0, 0, NULL, 0,
				 when, desc);
}

struct volume_group *import_vg_from_config_tree(const struct dm_config_tree *cft,
						struct format_instance *fid)
{
	struct volume_group *vg = NULL;
	struct text_vg_version_ops **vsn;
	int vg_missing;

	_init_text_import();

	for (vsn = &_text_vsn_list[0]; *vsn; vsn++) {
		if (!(*vsn)->check_version(cft))
			continue;
		/*
		 * The only path to this point uses cached vgmetadata,
		 * so it can use cached PV state too.
		 */
		if (!(vg = (*vsn)->read_vg(fid, cft, 1)))
			stack;
		else if ((vg_missing = vg_missing_pv_count(vg))) {
			log_verbose("There are %d physical volumes missing.",
				    vg_missing);
			vg_mark_partial_lvs(vg, 1);
			/* FIXME: move this code inside read_vg() */
		}
		break;
	}

	return vg;
}