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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-22 17:35:59 +03:00
lvm2/lib/label/label.h
David Teigland e035e32350 scan: retry reading metadata on error
If label_scan encounters bad vg metadata, invalidate
bcache data for the device and reread the mda_header
and metadata text back to back.  With concurrent commands
modifying large metadata, it's possible that the entire
metadata area can be rewritten in the time between a
command reading the mda_header and reading the metadata
text that the header points to.  Since the label_scan
is just assembling an initial overview of devices, it
doesn't use locking to serialize with other commands
that may be modifying the vg metadata at the same time.
2021-07-06 10:10:23 -05:00

138 lines
4.3 KiB
C

/*
* Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 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
*/
#ifndef _LVM_LABEL_H
#define _LVM_LABEL_H
#include "lib/uuid/uuid.h"
#include "lib/device/device.h"
#include "lib/device/bcache.h"
#define LABEL_ID "LABELONE"
#define LABEL_SIZE SECTOR_SIZE /* Think very carefully before changing this */
#define LABEL_SCAN_SECTORS 4L
#define LABEL_SCAN_SIZE (LABEL_SCAN_SECTORS << SECTOR_SHIFT)
struct labeller;
struct dev_filter;
struct cmd_context;
struct logical_volume;
/* On disk - 32 bytes */
struct label_header {
int8_t id[8]; /* LABELONE */
uint64_t sector_xl; /* Sector number of this label */
uint32_t crc_xl; /* From next field to end of sector */
uint32_t offset_xl; /* Offset from start of struct to contents */
int8_t type[8]; /* LVM2 001 */
} __attribute__ ((packed));
/* In core */
struct label {
char type[8];
uint64_t sector;
struct labeller *labeller;
struct device *dev;
void *info;
};
struct labeller;
struct label_ops {
/*
* Is the device labelled with this format ?
*/
int (*can_handle) (struct labeller * l, void *buf, uint64_t sector);
/*
* Write a label to a volume.
*/
int (*write) (struct label * label, void *buf);
/*
* Read a label from a volume.
*/
int (*read) (struct cmd_context *cmd, struct labeller * l, struct device * dev,
void *label_buf, uint64_t label_sector, int *is_duplicate);
/*
* Populate label_type etc.
*/
int (*initialise_label) (struct labeller * l, struct label * label);
/*
* Destroy a previously read label.
*/
void (*destroy_label) (struct labeller * l, struct label * label);
/*
* Destructor.
*/
void (*destroy) (struct labeller * l);
};
struct labeller {
struct label_ops *ops;
const struct format_type *fmt;
};
int label_init(void);
void label_exit(void);
int label_register_handler(struct labeller *handler);
struct labeller *label_get_handler(const char *name);
int label_remove(struct device *dev);
int label_write(struct device *dev, struct label *label);
struct label *label_create(struct labeller *labeller);
void label_destroy(struct label *label);
extern struct bcache *scan_bcache;
int label_scan(struct cmd_context *cmd);
int label_scan_devs(struct cmd_context *cmd, struct dev_filter *f, struct dm_list *devs);
int label_scan_devs_cached(struct cmd_context *cmd, struct dev_filter *f, struct dm_list *devs);
int label_scan_devs_rw(struct cmd_context *cmd, struct dev_filter *f, struct dm_list *devs);
int label_scan_devs_excl(struct cmd_context *cmd, struct dev_filter *f, struct dm_list *devs);
int label_scan_dev(struct device *dev);
void label_scan_invalidate(struct device *dev);
void label_scan_invalidate_lv(struct cmd_context *cmd, struct logical_volume *lv);
void label_scan_drop(struct cmd_context *cmd);
void label_scan_destroy(struct cmd_context *cmd);
int label_scan_setup_bcache(void);
int label_scan_open(struct device *dev);
int label_scan_open_excl(struct device *dev);
int label_scan_open_rw(struct device *dev);
int label_scan_reopen_rw(struct device *dev);
int label_read_pvid(struct device *dev, int *has_pvid);
int label_scan_for_pvid(struct cmd_context *cmd, char *pvid, struct device **dev_out);
/*
* Wrappers around bcache equivalents.
* (these make it easier to disable bcache and revert to direct rw if needed)
*/
bool dev_read_bytes(struct device *dev, uint64_t start, size_t len, void *data);
bool dev_write_bytes(struct device *dev, uint64_t start, size_t len, void *data);
bool dev_write_zeros(struct device *dev, uint64_t start, size_t len);
bool dev_set_bytes(struct device *dev, uint64_t start, size_t len, uint8_t val);
bool dev_invalidate_bytes(struct device *dev, uint64_t start, size_t len);
void dev_invalidate(struct device *dev);
void dev_set_last_byte(struct device *dev, uint64_t offset);
void dev_unset_last_byte(struct device *dev);
#endif