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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.
395 lines
9.0 KiB
C
395 lines
9.0 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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#include "lib.h"
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#include "label.h"
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#include "crc.h"
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#include "xlate.h"
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#include "lvmcache.h"
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#include "lvmetad.h"
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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/* FIXME Allow for larger labels? Restricted to single sector currently */
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/*
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* Internal labeller struct.
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*/
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struct labeller_i {
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struct dm_list list;
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struct labeller *l;
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char name[0];
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};
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static struct dm_list _labellers;
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static struct labeller_i *_alloc_li(const char *name, struct labeller *l)
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{
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struct labeller_i *li;
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size_t len;
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len = sizeof(*li) + strlen(name) + 1;
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if (!(li = dm_malloc(len))) {
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log_error("Couldn't allocate memory for labeller list object.");
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return NULL;
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}
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li->l = l;
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strcpy(li->name, name);
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return li;
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}
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int label_init(void)
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{
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dm_list_init(&_labellers);
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return 1;
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}
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void label_exit(void)
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{
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struct labeller_i *li, *tli;
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dm_list_iterate_items_safe(li, tli, &_labellers) {
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dm_list_del(&li->list);
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li->l->ops->destroy(li->l);
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dm_free(li);
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}
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dm_list_init(&_labellers);
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}
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int label_register_handler(struct labeller *handler)
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{
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struct labeller_i *li;
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if (!(li = _alloc_li(handler->fmt->name, handler)))
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return_0;
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dm_list_add(&_labellers, &li->list);
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return 1;
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}
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struct labeller *label_get_handler(const char *name)
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{
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struct labeller_i *li;
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dm_list_iterate_items(li, &_labellers)
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if (!strcmp(li->name, name))
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return li->l;
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return NULL;
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}
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static void _update_lvmcache_orphan(struct lvmcache_info *info)
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{
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struct lvmcache_vgsummary vgsummary_orphan = {
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.vgname = lvmcache_fmt(info)->orphan_vg_name,
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};
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memcpy(&vgsummary_orphan.vgid, lvmcache_fmt(info)->orphan_vg_name, strlen(lvmcache_fmt(info)->orphan_vg_name));
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lvmcache_update_vgname_and_id(info, &vgsummary_orphan);
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}
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static struct labeller *_find_labeller(struct device *dev, char *buf,
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uint64_t *label_sector,
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uint64_t scan_sector)
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{
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struct labeller_i *li;
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struct labeller *r = NULL;
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struct label_header *lh;
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struct lvmcache_info *info;
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uint64_t sector;
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int found = 0;
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char readbuf[LABEL_SCAN_SIZE] __attribute__((aligned(8)));
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if (!dev_read(dev, scan_sector << SECTOR_SHIFT,
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LABEL_SCAN_SIZE, readbuf)) {
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log_debug_devs("%s: Failed to read label area", dev_name(dev));
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goto out;
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}
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/* Scan a few sectors for a valid label */
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for (sector = 0; sector < LABEL_SCAN_SECTORS;
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sector += LABEL_SIZE >> SECTOR_SHIFT) {
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lh = (struct label_header *) (readbuf +
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(sector << SECTOR_SHIFT));
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if (!strncmp((char *)lh->id, LABEL_ID, sizeof(lh->id))) {
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if (found) {
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log_error("Ignoring additional label on %s at "
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"sector %" PRIu64, dev_name(dev),
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sector + scan_sector);
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}
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if (xlate64(lh->sector_xl) != sector + scan_sector) {
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log_info("%s: Label for sector %" PRIu64
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" found at sector %" PRIu64
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" - ignoring", dev_name(dev),
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(uint64_t)xlate64(lh->sector_xl),
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sector + scan_sector);
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continue;
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}
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if (calc_crc(INITIAL_CRC, (uint8_t *)&lh->offset_xl, LABEL_SIZE -
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((uint8_t *) &lh->offset_xl - (uint8_t *) lh)) !=
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xlate32(lh->crc_xl)) {
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log_info("Label checksum incorrect on %s - "
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"ignoring", dev_name(dev));
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continue;
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}
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if (found)
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continue;
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}
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dm_list_iterate_items(li, &_labellers) {
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if (li->l->ops->can_handle(li->l, (char *) lh,
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sector + scan_sector)) {
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log_very_verbose("%s: %s label detected at "
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"sector %" PRIu64,
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dev_name(dev), li->name,
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sector + scan_sector);
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if (found) {
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log_error("Ignoring additional label "
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"on %s at sector %" PRIu64,
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dev_name(dev),
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sector + scan_sector);
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continue;
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}
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r = li->l;
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memcpy(buf, lh, LABEL_SIZE);
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if (label_sector)
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*label_sector = sector + scan_sector;
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found = 1;
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break;
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}
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}
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}
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out:
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if (!found) {
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if ((info = lvmcache_info_from_pvid(dev->pvid, 0)))
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_update_lvmcache_orphan(info);
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log_very_verbose("%s: No label detected", dev_name(dev));
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}
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return r;
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}
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/* FIXME Also wipe associated metadata area headers? */
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int label_remove(struct device *dev)
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{
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char buf[LABEL_SIZE] __attribute__((aligned(8)));
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char readbuf[LABEL_SCAN_SIZE] __attribute__((aligned(8)));
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int r = 1;
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uint64_t sector;
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int wipe;
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struct labeller_i *li;
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struct label_header *lh;
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memset(buf, 0, LABEL_SIZE);
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log_very_verbose("Scanning for labels to wipe from %s", dev_name(dev));
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if (!dev_open(dev))
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return_0;
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/*
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* We flush the device just in case someone is stupid
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* enough to be trying to import an open pv into lvm.
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*/
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dev_flush(dev);
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if (!dev_read(dev, UINT64_C(0), LABEL_SCAN_SIZE, readbuf)) {
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log_debug_devs("%s: Failed to read label area", dev_name(dev));
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goto out;
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}
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/* Scan first few sectors for anything looking like a label */
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for (sector = 0; sector < LABEL_SCAN_SECTORS;
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sector += LABEL_SIZE >> SECTOR_SHIFT) {
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lh = (struct label_header *) (readbuf +
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(sector << SECTOR_SHIFT));
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wipe = 0;
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if (!strncmp((char *)lh->id, LABEL_ID, sizeof(lh->id))) {
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if (xlate64(lh->sector_xl) == sector)
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wipe = 1;
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} else {
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dm_list_iterate_items(li, &_labellers) {
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if (li->l->ops->can_handle(li->l, (char *) lh,
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sector)) {
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wipe = 1;
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break;
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}
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}
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}
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if (wipe) {
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log_info("%s: Wiping label at sector %" PRIu64,
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dev_name(dev), sector);
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if (!dev_write(dev, sector << SECTOR_SHIFT, LABEL_SIZE,
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buf)) {
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log_error("Failed to remove label from %s at "
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"sector %" PRIu64, dev_name(dev),
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sector);
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r = 0;
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}
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}
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}
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out:
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if (!dev_close(dev))
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stack;
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return r;
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}
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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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{
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char buf[LABEL_SIZE] __attribute__((aligned(8)));
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struct labeller *l;
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uint64_t sector;
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struct lvmcache_info *info;
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int r = 0;
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if ((info = lvmcache_info_from_pvid(dev->pvid, 1))) {
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log_debug_devs("Using cached label for %s", dev_name(dev));
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*result = lvmcache_get_label(info);
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return 1;
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}
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if (!dev_open_readonly(dev)) {
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stack;
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if ((info = lvmcache_info_from_pvid(dev->pvid, 0)))
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_update_lvmcache_orphan(info);
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return r;
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}
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if ((l = _find_labeller(dev, buf, §or, scan_sector)))
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if ((r = (l->ops->read)(l, dev, buf, result)) && result && *result) {
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(*result)->dev = dev;
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(*result)->sector = sector;
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}
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if (!dev_close(dev))
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stack;
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return r;
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}
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/* Caller may need to use label_get_handler to create label struct! */
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int label_write(struct device *dev, struct label *label)
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{
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char buf[LABEL_SIZE] __attribute__((aligned(8)));
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struct label_header *lh = (struct label_header *) buf;
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int r = 1;
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if (!label->labeller->ops->write) {
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log_error("Label handler does not support label writes");
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return 0;
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}
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if ((LABEL_SIZE + (label->sector << SECTOR_SHIFT)) > LABEL_SCAN_SIZE) {
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log_error("Label sector %" PRIu64 " beyond range (%ld)",
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label->sector, LABEL_SCAN_SECTORS);
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return 0;
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}
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memset(buf, 0, LABEL_SIZE);
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strncpy((char *)lh->id, LABEL_ID, sizeof(lh->id));
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lh->sector_xl = xlate64(label->sector);
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lh->offset_xl = xlate32(sizeof(*lh));
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if (!(label->labeller->ops->write)(label, buf))
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return_0;
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lh->crc_xl = xlate32(calc_crc(INITIAL_CRC, (uint8_t *)&lh->offset_xl, LABEL_SIZE -
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((uint8_t *) &lh->offset_xl - (uint8_t *) lh)));
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if (!dev_open(dev))
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return_0;
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log_info("%s: Writing label to sector %" PRIu64 " with stored offset %"
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PRIu32 ".", dev_name(dev), label->sector,
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xlate32(lh->offset_xl));
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if (!dev_write(dev, label->sector << SECTOR_SHIFT, LABEL_SIZE, buf)) {
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log_debug_devs("Failed to write label to %s", dev_name(dev));
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r = 0;
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}
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if (!dev_close(dev))
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stack;
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return r;
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}
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/* Unused */
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int label_verify(struct device *dev)
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{
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struct labeller *l;
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char buf[LABEL_SIZE] __attribute__((aligned(8)));
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uint64_t sector;
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struct lvmcache_info *info;
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int r = 0;
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if (!dev_open_readonly(dev)) {
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if ((info = lvmcache_info_from_pvid(dev->pvid, 0)))
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_update_lvmcache_orphan(info);
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return_0;
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}
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if (!(l = _find_labeller(dev, buf, §or, UINT64_C(0))))
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goto out;
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r = l->ops->verify ? l->ops->verify(l, buf, sector) : 1;
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out:
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if (!dev_close(dev))
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stack;
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return r;
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}
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void label_destroy(struct label *label)
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{
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label->labeller->ops->destroy_label(label->labeller, label);
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dm_free(label);
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}
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struct label *label_create(struct labeller *labeller)
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{
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struct label *label;
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if (!(label = dm_zalloc(sizeof(*label)))) {
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log_error("label allocaction failed");
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return NULL;
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}
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label->labeller = labeller;
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labeller->ops->initialise_label(labeller, label);
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return label;
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}
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