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git://sourceware.org/git/lvm2.git
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6407d184d1
Refactor the recent metadata-reading optimisation patches. Remove the recently-added cache fields from struct labeller and struct format_instance. Instead, introduce struct lvmcache_vgsummary to wrap the VG information that lvmcache holds and add the metadata size and checksum to it. Allow this VG summary information to be looked up by metadata size + checksum. Adjust the debug log messages to make it clear when this shortcut has been successful. (This changes the optimisation slightly, and might be extendable further.) Add struct cached_vg_fmtdata to format-specific vg_read calls to preserve state alongside the VG across separate calls and indicate if the details supplied match, avoiding the need to read and process the VG metadata again.
110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/*
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* Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LVM_LABEL_H
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#define _LVM_LABEL_H
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#include "uuid.h"
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#include "device.h"
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#define LABEL_ID "LABELONE"
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#define LABEL_SIZE SECTOR_SIZE /* Think very carefully before changing this */
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#define LABEL_SCAN_SECTORS 4L
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#define LABEL_SCAN_SIZE (LABEL_SCAN_SECTORS << SECTOR_SHIFT)
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struct labeller;
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void allow_reads_with_lvmetad(void);
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/* On disk - 32 bytes */
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struct label_header {
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int8_t id[8]; /* LABELONE */
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uint64_t sector_xl; /* Sector number of this label */
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uint32_t crc_xl; /* From next field to end of sector */
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uint32_t offset_xl; /* Offset from start of struct to contents */
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int8_t type[8]; /* LVM2 001 */
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} __attribute__ ((packed));
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/* In core */
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struct label {
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char type[8];
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uint64_t sector;
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struct labeller *labeller;
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struct device *dev;
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void *info;
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};
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struct labeller;
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struct label_ops {
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/*
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* Is the device labelled with this format ?
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*/
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int (*can_handle) (struct labeller * l, void *buf, uint64_t sector);
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/*
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* Write a label to a volume.
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*/
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int (*write) (struct label * label, void *buf);
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/*
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* Read a label from a volume.
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*/
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int (*read) (struct labeller * l, struct device * dev,
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void *buf, struct label ** label);
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/*
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* Additional consistency checks for the paranoid.
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*/
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int (*verify) (struct labeller * l, void *buf, uint64_t sector);
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/*
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* Populate label_type etc.
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*/
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int (*initialise_label) (struct labeller * l, struct label * label);
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/*
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* Destroy a previously read label.
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*/
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void (*destroy_label) (struct labeller * l, struct label * label);
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/*
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* Destructor.
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*/
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void (*destroy) (struct labeller * l);
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};
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struct labeller {
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struct label_ops *ops;
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const struct format_type *fmt;
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};
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int label_init(void);
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void label_exit(void);
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int label_register_handler(struct labeller *handler);
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struct labeller *label_get_handler(const char *name);
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int label_remove(struct device *dev);
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int label_read(struct device *dev, struct label **result,
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uint64_t scan_sector);
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int label_write(struct device *dev, struct label *label);
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int label_verify(struct device *dev);
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struct label *label_create(struct labeller *labeller);
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void label_destroy(struct label *label);
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#endif
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