mirror of
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137 lines
3.1 KiB
C
137 lines
3.1 KiB
C
/*
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* Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004-2006 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 "metadata.h"
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#include "toolcontext.h"
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#include "lv_alloc.h"
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int lv_is_origin(const struct logical_volume *lv)
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{
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return lv->origin_count ? 1 : 0;
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}
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int lv_is_cow(const struct logical_volume *lv)
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{
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return lv->snapshot ? 1 : 0;
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}
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int lv_is_visible(const struct logical_volume *lv)
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{
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if (lv->status & SNAPSHOT)
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return 0;
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if (lv_is_cow(lv)) {
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if (lv_is_virtual_origin(origin_from_cow(lv)))
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return 1;
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return lv_is_visible(origin_from_cow(lv));
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}
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return lv->status & VISIBLE_LV ? 1 : 0;
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}
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int lv_is_virtual_origin(const struct logical_volume *lv)
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{
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return (lv->status & VIRTUAL_ORIGIN) ? 1 : 0;
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}
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/* Given a cow LV, return the snapshot lv_segment that uses it */
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struct lv_segment *find_cow(const struct logical_volume *lv)
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{
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return lv->snapshot;
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}
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/* Given a cow LV, return its origin */
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struct logical_volume *origin_from_cow(const struct logical_volume *lv)
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{
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return lv->snapshot->origin;
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}
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void init_snapshot_seg(struct lv_segment *seg, struct logical_volume *origin,
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struct logical_volume *cow, uint32_t chunk_size)
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{
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seg->chunk_size = chunk_size;
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seg->origin = origin;
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seg->cow = cow;
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lv_set_hidden(cow);
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cow->snapshot = seg;
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origin->origin_count++;
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/* FIXME Assumes an invisible origin belongs to a sparse device */
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if (!lv_is_visible(origin))
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origin->status |= VIRTUAL_ORIGIN;
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seg->lv->status |= (SNAPSHOT | VIRTUAL);
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dm_list_add(&origin->snapshot_segs, &seg->origin_list);
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}
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int vg_add_snapshot(struct logical_volume *origin,
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struct logical_volume *cow, union lvid *lvid,
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uint32_t extent_count, uint32_t chunk_size)
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{
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struct logical_volume *snap;
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struct lv_segment *seg;
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/*
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* Is the cow device already being used ?
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*/
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if (lv_is_cow(cow)) {
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log_err("'%s' is already in use as a snapshot.", cow->name);
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return 0;
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}
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if (cow == origin) {
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log_error("Snapshot and origin LVs must differ.");
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return 0;
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}
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if (!(snap = lv_create_empty("snapshot%d",
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lvid, LVM_READ | LVM_WRITE | VISIBLE_LV,
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ALLOC_INHERIT, origin->vg)))
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return_0;
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snap->le_count = extent_count;
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if (!(seg = alloc_snapshot_seg(snap, 0, 0)))
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return_0;
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init_snapshot_seg(seg, origin, cow, chunk_size);
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return 1;
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}
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int vg_remove_snapshot(struct logical_volume *cow)
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{
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dm_list_del(&cow->snapshot->origin_list);
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cow->snapshot->origin->origin_count--;
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if (!lv_remove(cow->snapshot->lv)) {
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log_error("Failed to remove internal snapshot LV %s",
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cow->snapshot->lv->name);
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return 0;
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}
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cow->snapshot = NULL;
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lv_set_visible(cow);
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return 1;
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}
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