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lvm2/lib/cache/lvmcache.h
Zdenek Kabelac d992bbbaa3 Keep the cache content when the exported vg buffer is matching
Instead of regenerating config tree and parsing same data again,
check whether export_vg_to_buffer does not produce same string as
the one already cached - in this case keep it, otherwise throw cached
content away.

For the code simplicity calling _free_cached_vgmetadata() with
vgmetadata == NULL as the function handles this itself.

Note: sometimes export_vg_to_buffer() generates almost the same data
with just different time stamp, but for the patch simplicity,
data are reparsed in this case.

This patch currently helps for vgrefresh.
2011-03-30 13:14:34 +00:00

129 lines
4.7 KiB
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
*/
#ifndef _LVM_CACHE_H
#define _LVM_CACHE_H
#include "dev-cache.h"
#include "uuid.h"
#include "label.h"
#include "locking.h"
#define ORPHAN_PREFIX VG_ORPHANS
#define ORPHAN_VG_NAME(fmt) ORPHAN_PREFIX "_" fmt
#define CACHE_INVALID 0x00000001
#define CACHE_LOCKED 0x00000002
/* LVM specific per-volume info */
/* Eventual replacement for struct physical_volume perhaps? */
struct cmd_context;
struct format_type;
struct volume_group;
struct config_tree;
/* One per VG */
struct lvmcache_vginfo {
struct dm_list list; /* Join these vginfos together */
struct dm_list infos; /* List head for lvmcache_infos */
const struct format_type *fmt;
char *vgname; /* "" == orphan */
uint32_t status;
char vgid[ID_LEN + 1];
char _padding[7];
struct lvmcache_vginfo *next; /* Another VG with same name? */
char *creation_host;
size_t vgmetadata_size;
char *vgmetadata; /* Copy of VG metadata as format_text string */
struct config_tree *cft; /* Config tree created from vgmetadata */
/* Lifetime is directly tied to vgmetadata */
unsigned precommitted; /* Is vgmetadata live or precommitted? */
};
/* One per device */
struct lvmcache_info {
struct dm_list list; /* Join VG members together */
struct dm_list mdas; /* list head for metadata areas */
struct dm_list das; /* list head for data areas */
struct lvmcache_vginfo *vginfo; /* NULL == unknown */
struct label *label;
const struct format_type *fmt;
struct device *dev;
uint64_t device_size; /* Bytes */
uint32_t status;
};
int lvmcache_init(void);
void lvmcache_destroy(struct cmd_context *cmd, int retain_orphans);
/* Set full_scan to 1 to reread every filtered device label or
* 2 to rescan /dev for new devices */
int lvmcache_label_scan(struct cmd_context *cmd, int full_scan);
/* Add/delete a device */
struct lvmcache_info *lvmcache_add(struct labeller *labeller, const char *pvid,
struct device *dev,
const char *vgname, const char *vgid,
uint32_t vgstatus);
int lvmcache_add_orphan_vginfo(const char *vgname, struct format_type *fmt);
void lvmcache_del(struct lvmcache_info *info);
/* Update things */
int lvmcache_update_vgname_and_id(struct lvmcache_info *info,
const char *vgname, const char *vgid,
uint32_t vgstatus, const char *hostname);
int lvmcache_update_vg(struct volume_group *vg, unsigned precommitted);
void lvmcache_lock_vgname(const char *vgname, int read_only);
void lvmcache_unlock_vgname(const char *vgname);
int lvmcache_verify_lock_order(const char *vgname);
/* Queries */
const struct format_type *fmt_from_vgname(const char *vgname, const char *vgid, unsigned revalidate_labels);
struct lvmcache_vginfo *vginfo_from_vgname(const char *vgname,
const char *vgid);
struct lvmcache_vginfo *vginfo_from_vgid(const char *vgid);
struct lvmcache_info *info_from_pvid(const char *pvid, int valid_only);
const char *vgname_from_vgid(struct dm_pool *mem, const char *vgid);
struct device *device_from_pvid(struct cmd_context *cmd, const struct id *pvid,
unsigned *scan_done_once);
const char *pvid_from_devname(struct cmd_context *cmd,
const char *dev_name);
char *lvmcache_vgname_from_pvid(struct cmd_context *cmd, const char *pvid);
int vgs_locked(void);
int vgname_is_locked(const char *vgname);
/* Returns list of struct str_lists containing pool-allocated copy of vgnames */
/* If include_internal is not set, return only proper vg names. */
struct dm_list *lvmcache_get_vgnames(struct cmd_context *cmd,
int include_internal);
/* Returns list of struct str_lists containing pool-allocated copy of vgids */
/* If include_internal is not set, return only proper vg ids. */
struct dm_list *lvmcache_get_vgids(struct cmd_context *cmd,
int include_internal);
/* Returns list of struct str_lists containing pool-allocated copy of pvids */
struct dm_list *lvmcache_get_pvids(struct cmd_context *cmd, const char *vgname,
const char *vgid);
/* Returns cached volume group metadata. */
struct volume_group *lvmcache_get_vg(const char *vgid, unsigned precommitted);
void lvmcache_drop_metadata(const char *vgname, int drop_precommitted);
void lvmcache_commit_metadata(const char *vgname);
#endif