lvm2/lib/metadata/metadata.h

/*
 * Copyright (C) 2001 Sistina Software (UK) Limited.
 *
 * This file is released under the LGPL.
 *
 * This is the in core representation of a volume group and its
 * associated physical and logical volumes.
 */

#ifndef _LVM_METADATA_H
#define _LVM_METADATA_H

#include "ctype.h"
#include "dev-cache.h"
#include "list.h"
#include "uuid.h"

#include <sys/types.h>
#include <asm/page.h>

#define NAME_LEN 128
#define MAX_STRIPES 128
#define SECTOR_SHIFT 9L
#define SECTOR_SIZE ( 1L << SECTOR_SHIFT )
#define STRIPE_SIZE_MIN ( PAGE_SIZE >> SECTOR_SHIFT)	/* PAGESIZE in sectors */
#define STRIPE_SIZE_MAX ( 512L * 1024L >> SECTOR_SHIFT)	/* 512 KB in sectors */
#define PV_MIN_SIZE ( 512L * 1024L >> SECTOR_SHIFT)	/* 512 KB in sectors */
#define PE_ALIGN (65536UL >> SECTOR_SHIFT)	/* PE alignment */

/* Various flags */
/* Note that the bits no longer necessarily correspond to LVM1 disk format */

#define PARTIAL_VG		0x00000001	/* VG */
#define EXPORTED_VG          	0x00000002	/* VG PV */
#define RESIZEABLE_VG        	0x00000004	/* VG */

/* May any free extents on this PV be used or must they be left free? */
#define ALLOCATABLE_PV         	0x00000008	/* PV */

#define SPINDOWN_LV          	0x00000010	/* LV */
#define BADBLOCK_ON       	0x00000020	/* LV */
#define VISIBLE_LV		0x00000040	/* LV */
#define FIXED_MINOR		0x00000080	/* LV */
/* FIXME Remove when metadata restructuring is completed */
#define SNAPSHOT		0x00001000	/* LV - temp internal use only */

#define LVM_READ              	0x00000100	/* LV VG */
#define LVM_WRITE             	0x00000200	/* LV VG */
#define CLUSTERED         	0x00000400	/* VG */
#define SHARED            	0x00000800	/* VG */

/* Format features flags */
#define FMT_SEGMENTS		0x00000001	/* Arbitrary segment params? */
#define FMT_MDAS		0x00000002	/* Proper metadata areas? */

typedef enum {
	ALLOC_DEFAULT,
	ALLOC_NEXT_FREE,
	ALLOC_CONTIGUOUS
} alloc_policy_t;

typedef enum {
	SEG_STRIPED,
	SEG_SNAPSHOT,
	SEG_MIRROR
} segment_type_t;

struct cmd_context;
struct format_handler;
struct labeller;

struct format_type {
	struct list list;
	struct cmd_context *cmd;
	struct format_handler *ops;
	struct labeller *labeller;
	const char *name;
	const char *alias;
	uint32_t features;
	void *library;
	void *private;
};

struct physical_volume {
	struct id id;
	struct device *dev;
	const struct format_type *fmt;
	const char *vg_name;

	uint32_t status;
	uint64_t size;

	/* physical extents */
	uint32_t pe_size;
	uint64_t pe_start;
	uint32_t pe_count;
	uint32_t pe_alloc_count;
};

struct metadata_area;
struct format_instance;

/* Per-format per-metadata area operations */
struct metadata_area_ops {
	struct volume_group *(*vg_read) (struct format_instance * fi,
					 const char *vg_name,
					 struct metadata_area * mda);
	/*
	 * Write out complete VG metadata.  You must ensure internal
	 * consistency before calling. eg. PEs can't refer to PVs not
	 * part of the VG.
	 *
	 * It is also the responsibility of the caller to ensure external
	 * consistency, eg by calling pv_write() if removing PVs from
	 * a VG or calling vg_write() a second time if splitting a VG
	 * into two.
	 *
	 * vg_write() should not read or write from any PVs not included
	 * in the volume_group structure it is handed.
	 * (format1 currently breaks this rule.)
	 */
	int (*vg_write) (struct format_instance * fid, struct volume_group * vg,
			 struct metadata_area * mda);
	int (*vg_commit) (struct format_instance * fid,
			  struct volume_group * vg, struct metadata_area * mda);
	int (*vg_remove) (struct format_instance * fi, struct volume_group * vg,
			  struct metadata_area * mda);
};

struct metadata_area {
	struct list list;
	struct metadata_area_ops *ops;
	void *metadata_locn;
};

struct format_instance {
	const struct format_type *fmt;
	struct list metadata_areas;	/* e.g. metadata locations */
};

struct volume_group {
	struct cmd_context *cmd;
	struct format_instance *fid;
	uint32_t seqno;		/* Metadata sequence number */

	struct id id;
	char *name;
	char *system_id;

	uint32_t status;

	uint32_t extent_size;
	uint32_t extent_count;
	uint32_t free_count;

	uint32_t max_lv;
	uint32_t max_pv;

	/* physical volumes */
	uint32_t pv_count;
	struct list pvs;

	/* logical volumes */
	uint32_t lv_count;
	struct list lvs;

	/* snapshots */
	uint32_t snapshot_count;
	struct list snapshots;
};

struct lv_segment {
	struct list list;
	struct logical_volume *lv;

	segment_type_t type;
	uint32_t le;
	uint32_t len;

	/* FIXME Fields depend on segment type */
	uint32_t stripe_size;
	uint32_t stripes;
	struct logical_volume *origin;
	struct logical_volume *cow;
	uint32_t chunk_size;

	/* There will be one area for each stripe */
	struct {
		struct physical_volume *pv;
		uint32_t pe;
	} area[0];
};

struct logical_volume {
	union lvid lvid;
	char *name;

	struct volume_group *vg;

	uint32_t status;
	alloc_policy_t alloc;
	uint32_t read_ahead;
	int32_t minor;

	uint64_t size;
	uint32_t le_count;

	struct list segments;
};

struct snapshot {
	struct id id;

	int persistent;		/* boolean */
	uint32_t chunk_size;	/* in 512 byte sectors */

	struct logical_volume *origin;
	struct logical_volume *cow;
};

struct name_list {
	struct list list;
	char *name;
};

struct pv_list {
	struct list list;
	struct physical_volume *pv;
	struct list *mdas;
};

struct lv_list {
	struct list list;
	struct logical_volume *lv;
};

struct snapshot_list {
	struct list list;

	struct snapshot *snapshot;
};

struct mda_list {
	struct list list;
	struct device_area mda;
};

/*
 * Ownership of objects passes to caller.
 */
struct format_handler {
	/*
	 * Scan any metadata areas that aren't referenced in PV labels
	 */
	int (*scan) (const struct format_type * fmt);

	/*
	 * Return PV with given path.
	 */
	int (*pv_read) (const struct format_type * fmt, const char *pv_name,
			struct physical_volume * pv, struct list * mdas);

	/*
	 * Tweak an already filled out a pv ready for importing into a
	 * vg.  eg. pe_count is format specific.
	 */
	int (*pv_setup) (const struct format_type * fmt,
			 uint64_t pe_start, uint32_t extent_count,
			 uint32_t extent_size,
			 int pvmetadatacopies,
			 uint64_t pvmetadatasize, struct list * mdas,
			 struct physical_volume * pv, struct volume_group * vg);

	/*
	 * Write a PV structure to disk. Fails if the PV is in a VG ie
	 * pv->vg_name must be null.
	 */
	int (*pv_write) (const struct format_type * fmt,
			 struct physical_volume * pv, struct list * mdas,
			 int64_t label_sector);

	/*
	 * Tweak an already filled out a lv eg, check there
	 * aren't too many extents.
	 */
	int (*lv_setup) (struct format_instance * fi,
			 struct logical_volume * lv);

	/*
	 * Tweak an already filled out vg.  eg, max_pv is format
	 * specific.
	 */
	int (*vg_setup) (struct format_instance * fi, struct volume_group * vg);

	/*
	 * Create format instance with a particular metadata area
	 */
	struct format_instance *(*create_instance) (const struct format_type *
						    fmt, const char *vgname,
						    void *context);

	/*
	 * Destructor for format instance
	 */
	void (*destroy_instance) (struct format_instance * fid);

	/*
	 * Destructor for format type
	 */
	void (*destroy) (const struct format_type * fmt);
};

/*
 * Utility functions
 */
int vg_write(struct volume_group *vg);
struct volume_group *vg_read(struct cmd_context *cmd, const char *vg_name,
			     int *consistent);
struct volume_group *vg_read_by_vgid(struct cmd_context *cmd, const char *vgid);
struct physical_volume *pv_read(struct cmd_context *cmd, const char *pv_name,
				struct list *mdas, uint64_t *label_sector);
struct list *get_pvs(struct cmd_context *cmd);

/* Set full_scan to 1 to re-read every (filtered) device label */
struct list *get_vgs(struct cmd_context *cmd, int full_scan);

int pv_write(struct cmd_context *cmd, struct physical_volume *pv,
	     struct list *mdas, int64_t label_sector);

/* pe_start and pe_end relate to any existing data so that new metadata
 * areas can avoid overlap */
struct physical_volume *pv_create(const struct format_type *fmt,
				  struct device *dev,
				  struct id *id,
				  uint64_t size,
				  uint64_t pe_start,
				  uint32_t existing_extent_count,
				  uint32_t existing_extent_size,
				  int pvmetadatacopies,
				  uint64_t pvmetadatasize, struct list *mdas);

struct volume_group *vg_create(struct cmd_context *cmd, const char *name,
			       uint32_t extent_size, uint32_t max_pv,
			       uint32_t max_lv, int pv_count, char **pv_names);
int vg_remove(struct volume_group *vg);
int vg_rename(struct cmd_context *cmd, struct volume_group *vg,
	      const char *new_name);
int vg_extend(struct format_instance *fi, struct volume_group *vg,
	      int pv_count, char **pv_names);

/*
 * Create a new LV within a given volume group.
 *
 */
struct logical_volume *lv_create(struct format_instance *fi,
				 const char *name,
				 uint32_t status,
				 alloc_policy_t alloc,
				 uint32_t stripes,
				 uint32_t stripe_size,
				 uint32_t extents,
				 struct volume_group *vg,
				 struct list *acceptable_pvs);

int lv_reduce(struct format_instance *fi,
	      struct logical_volume *lv, uint32_t extents);

int lv_extend(struct format_instance *fi,
	      struct logical_volume *lv,
	      uint32_t stripes,
	      uint32_t stripe_size,
	      uint32_t extents, struct list *allocatable_pvs);

/* lv must be part of vg->lvs */
int lv_remove(struct volume_group *vg, struct logical_volume *lv);

/* Manipulate PV structures */
int pv_add(struct volume_group *vg, struct physical_volume *pv);
int pv_remove(struct volume_group *vg, struct physical_volume *pv);
struct physical_volume *pv_find(struct volume_group *vg, const char *pv_name);

/* Find a PV within a given VG */
struct pv_list *find_pv_in_vg(struct volume_group *vg, const char *pv_name);
struct physical_volume *find_pv_in_vg_by_uuid(struct volume_group *vg,
					      struct id *id);

/* Find an LV within a given VG */
struct lv_list *find_lv_in_vg(struct volume_group *vg, const char *lv_name);
struct lv_list *find_lv_in_vg_by_lvid(struct volume_group *vg,
				      const union lvid *lvid);

/* Return the VG that contains a given LV (based on path given in lv_name) */
/* or environment var */
struct volume_group *find_vg_with_lv(const char *lv_name);

/* Find LV with given lvid (used during activation) */
struct logical_volume *lv_from_lvid(struct cmd_context *cmd,
				    const char *lvid_s);

/* FIXME Merge these functions with ones above */
struct physical_volume *find_pv(struct volume_group *vg, struct device *dev);
struct logical_volume *find_lv(struct volume_group *vg, const char *lv_name);

/*
 * Remove a dev_dir if present.
 */
const char *strip_dir(const char *vg_name, const char *dir);

/*
 * Checks that an lv has no gaps or overlapping segments.
 */
int lv_check_segments(struct logical_volume *lv);

/*
 * Sometimes (eg, after an lvextend), it is possible to merge two
 * adjacent segments into a single segment.  This function trys
 * to merge as many segments as possible.
 */
int lv_merge_segments(struct logical_volume *lv);

/*
 * Useful functions for managing snapshots.
 */
int lv_is_origin(const struct logical_volume *lv);
int lv_is_cow(const struct logical_volume *lv);

struct snapshot *find_cow(const struct logical_volume *lv);
struct snapshot *find_origin(const struct logical_volume *lv);
struct list *find_snapshots(const struct logical_volume *lv);

int vg_add_snapshot(struct logical_volume *origin,
		    struct logical_volume *cow,
		    int persistent, struct id *id, uint32_t chunk_size);

int vg_remove_snapshot(struct volume_group *vg, struct logical_volume *cow);

static inline int validate_vgname(const char *n)
{
	register char c;
	register int len = 0;

	if (!n || !*n)
		return 0;

	/* Hyphen used as VG-LV separator - ambiguity if LV starts with it */
	if (*n == '-')
		return 0;

	while ((len++, c = *n++))
		if (!isalnum(c) && c != '.' && c != '_' && c != '-' && c != '+')
			return 0;

	if (len > NAME_LEN)
		return 0;

	return 1;
}

#endif