dm: add persistent data library
The persistent-data library offers a re-usable framework for the storage and management of on-disk metadata in device-mapper targets. It's used by the thin-provisioning target in the next patch and in an upcoming hierarchical storage target. For further information, please read Documentation/device-mapper/persistent-data.txt Signed-off-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Joe Thornber
committed by
Alasdair G Kergon
Alasdair G Kergon
parent
95d402f057
commit
3241b1d3e0
596
drivers/md/persistent-data/dm-space-map-metadata.c
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596
drivers/md/persistent-data/dm-space-map-metadata.c
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@@ -0,0 +1,596 @@
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/*
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* Copyright (C) 2011 Red Hat, Inc.
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*
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* This file is released under the GPL.
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*/
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#include "dm-space-map.h"
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#include "dm-space-map-common.h"
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#include "dm-space-map-metadata.h"
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "space map metadata"
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/*----------------------------------------------------------------*/
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/*
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* Space map interface.
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*
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* The low level disk format is written using the standard btree and
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* transaction manager. This means that performing disk operations may
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* cause us to recurse into the space map in order to allocate new blocks.
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* For this reason we have a pool of pre-allocated blocks large enough to
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* service any metadata_ll_disk operation.
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*/
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/*
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* FIXME: we should calculate this based on the size of the device.
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* Only the metadata space map needs this functionality.
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*/
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#define MAX_RECURSIVE_ALLOCATIONS 1024
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enum block_op_type {
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BOP_INC,
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BOP_DEC
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};
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struct block_op {
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enum block_op_type type;
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dm_block_t block;
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};
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struct sm_metadata {
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struct dm_space_map sm;
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struct ll_disk ll;
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struct ll_disk old_ll;
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dm_block_t begin;
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unsigned recursion_count;
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unsigned allocated_this_transaction;
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unsigned nr_uncommitted;
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struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS];
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};
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static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
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{
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struct block_op *op;
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if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) {
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DMERR("too many recursive allocations");
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return -ENOMEM;
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}
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op = smm->uncommitted + smm->nr_uncommitted++;
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op->type = type;
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op->block = b;
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return 0;
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}
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static int commit_bop(struct sm_metadata *smm, struct block_op *op)
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{
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int r = 0;
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enum allocation_event ev;
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switch (op->type) {
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case BOP_INC:
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r = sm_ll_inc(&smm->ll, op->block, &ev);
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break;
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case BOP_DEC:
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r = sm_ll_dec(&smm->ll, op->block, &ev);
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break;
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}
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return r;
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}
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static void in(struct sm_metadata *smm)
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{
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smm->recursion_count++;
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}
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static int out(struct sm_metadata *smm)
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{
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int r = 0;
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/*
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* If we're not recursing then very bad things are happening.
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*/
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if (!smm->recursion_count) {
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DMERR("lost track of recursion depth");
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return -ENOMEM;
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}
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if (smm->recursion_count == 1 && smm->nr_uncommitted) {
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while (smm->nr_uncommitted && !r) {
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smm->nr_uncommitted--;
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r = commit_bop(smm, smm->uncommitted +
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smm->nr_uncommitted);
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if (r)
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break;
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}
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}
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smm->recursion_count--;
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return r;
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}
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/*
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* When using the out() function above, we often want to combine an error
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* code for the operation run in the recursive context with that from
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* out().
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*/
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static int combine_errors(int r1, int r2)
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{
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return r1 ? r1 : r2;
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}
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static int recursing(struct sm_metadata *smm)
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{
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return smm->recursion_count;
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}
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static void sm_metadata_destroy(struct dm_space_map *sm)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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kfree(smm);
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}
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static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
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{
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DMERR("doesn't support extend");
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return -EINVAL;
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}
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static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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*count = smm->ll.nr_blocks;
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return 0;
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}
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static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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*count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
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smm->allocated_this_transaction;
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return 0;
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}
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static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
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uint32_t *result)
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{
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int r, i;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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unsigned adjustment = 0;
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/*
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* We may have some uncommitted adjustments to add. This list
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* should always be really short.
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*/
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for (i = 0; i < smm->nr_uncommitted; i++) {
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struct block_op *op = smm->uncommitted + i;
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if (op->block != b)
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continue;
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switch (op->type) {
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case BOP_INC:
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adjustment++;
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break;
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case BOP_DEC:
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adjustment--;
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break;
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}
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}
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r = sm_ll_lookup(&smm->ll, b, result);
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if (r)
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return r;
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*result += adjustment;
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return 0;
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}
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static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
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dm_block_t b, int *result)
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{
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int r, i, adjustment = 0;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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uint32_t rc;
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/*
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* We may have some uncommitted adjustments to add. This list
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* should always be really short.
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*/
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for (i = 0; i < smm->nr_uncommitted; i++) {
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struct block_op *op = smm->uncommitted + i;
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if (op->block != b)
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continue;
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switch (op->type) {
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case BOP_INC:
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adjustment++;
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break;
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case BOP_DEC:
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adjustment--;
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break;
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}
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}
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if (adjustment > 1) {
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*result = 1;
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return 0;
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}
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r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
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if (r)
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return r;
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if (rc == 3)
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/*
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* We err on the side of caution, and always return true.
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*/
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*result = 1;
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else
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*result = rc + adjustment > 1;
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return 0;
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}
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static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
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uint32_t count)
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{
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int r, r2;
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enum allocation_event ev;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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if (smm->recursion_count) {
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DMERR("cannot recurse set_count()");
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return -EINVAL;
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}
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in(smm);
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r = sm_ll_insert(&smm->ll, b, count, &ev);
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r2 = out(smm);
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return combine_errors(r, r2);
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}
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static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b)
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{
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int r, r2 = 0;
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enum allocation_event ev;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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if (recursing(smm))
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r = add_bop(smm, BOP_INC, b);
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else {
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in(smm);
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r = sm_ll_inc(&smm->ll, b, &ev);
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r2 = out(smm);
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}
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return combine_errors(r, r2);
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}
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static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b)
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{
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int r, r2 = 0;
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enum allocation_event ev;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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if (recursing(smm))
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r = add_bop(smm, BOP_DEC, b);
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else {
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in(smm);
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r = sm_ll_dec(&smm->ll, b, &ev);
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r2 = out(smm);
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}
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return combine_errors(r, r2);
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}
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static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
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{
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int r, r2 = 0;
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enum allocation_event ev;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b);
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if (r)
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return r;
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smm->begin = *b + 1;
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if (recursing(smm))
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r = add_bop(smm, BOP_INC, *b);
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else {
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in(smm);
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r = sm_ll_inc(&smm->ll, *b, &ev);
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r2 = out(smm);
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}
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if (!r)
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smm->allocated_this_transaction++;
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return combine_errors(r, r2);
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}
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static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
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{
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int r = sm_metadata_new_block_(sm, b);
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if (r)
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DMERR("out of metadata space");
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return r;
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}
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static int sm_metadata_commit(struct dm_space_map *sm)
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{
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int r;
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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r = sm_ll_commit(&smm->ll);
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if (r)
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return r;
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memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
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smm->begin = 0;
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smm->allocated_this_transaction = 0;
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return 0;
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}
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static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
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{
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*result = sizeof(struct disk_sm_root);
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return 0;
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}
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static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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struct disk_sm_root root_le;
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root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
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root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
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root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
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root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
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if (max < sizeof(root_le))
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return -ENOSPC;
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memcpy(where_le, &root_le, sizeof(root_le));
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return 0;
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}
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static struct dm_space_map ops = {
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.destroy = sm_metadata_destroy,
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.extend = sm_metadata_extend,
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.get_nr_blocks = sm_metadata_get_nr_blocks,
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.get_nr_free = sm_metadata_get_nr_free,
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.get_count = sm_metadata_get_count,
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.count_is_more_than_one = sm_metadata_count_is_more_than_one,
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.set_count = sm_metadata_set_count,
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.inc_block = sm_metadata_inc_block,
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.dec_block = sm_metadata_dec_block,
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.new_block = sm_metadata_new_block,
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.commit = sm_metadata_commit,
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.root_size = sm_metadata_root_size,
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.copy_root = sm_metadata_copy_root
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};
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/*----------------------------------------------------------------*/
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/*
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* When a new space map is created that manages its own space. We use
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* this tiny bootstrap allocator.
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*/
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static void sm_bootstrap_destroy(struct dm_space_map *sm)
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{
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}
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static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
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{
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DMERR("boostrap doesn't support extend");
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return -EINVAL;
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}
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static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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return smm->ll.nr_blocks;
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}
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static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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*count = smm->ll.nr_blocks - smm->begin;
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return 0;
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}
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static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
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uint32_t *result)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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return b < smm->begin ? 1 : 0;
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}
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static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
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dm_block_t b, int *result)
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{
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*result = 0;
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return 0;
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}
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static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
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uint32_t count)
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{
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DMERR("boostrap doesn't support set_count");
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return -EINVAL;
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}
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static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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/*
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* We know the entire device is unused.
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*/
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if (smm->begin == smm->ll.nr_blocks)
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return -ENOSPC;
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*b = smm->begin++;
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return 0;
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}
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static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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return add_bop(smm, BOP_INC, b);
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}
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static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b)
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{
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struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
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return add_bop(smm, BOP_DEC, b);
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}
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static int sm_bootstrap_commit(struct dm_space_map *sm)
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{
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return 0;
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}
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static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
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{
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DMERR("boostrap doesn't support root_size");
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return -EINVAL;
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}
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static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
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size_t max)
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{
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DMERR("boostrap doesn't support copy_root");
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return -EINVAL;
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}
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static struct dm_space_map bootstrap_ops = {
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.destroy = sm_bootstrap_destroy,
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.extend = sm_bootstrap_extend,
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.get_nr_blocks = sm_bootstrap_get_nr_blocks,
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.get_nr_free = sm_bootstrap_get_nr_free,
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.get_count = sm_bootstrap_get_count,
|
||||
.count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
|
||||
.set_count = sm_bootstrap_set_count,
|
||||
.inc_block = sm_bootstrap_inc_block,
|
||||
.dec_block = sm_bootstrap_dec_block,
|
||||
.new_block = sm_bootstrap_new_block,
|
||||
.commit = sm_bootstrap_commit,
|
||||
.root_size = sm_bootstrap_root_size,
|
||||
.copy_root = sm_bootstrap_copy_root
|
||||
};
|
||||
|
||||
/*----------------------------------------------------------------*/
|
||||
|
||||
struct dm_space_map *dm_sm_metadata_init(void)
|
||||
{
|
||||
struct sm_metadata *smm;
|
||||
|
||||
smm = kmalloc(sizeof(*smm), GFP_KERNEL);
|
||||
if (!smm)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
|
||||
memcpy(&smm->sm, &ops, sizeof(smm->sm));
|
||||
|
||||
return &smm->sm;
|
||||
}
|
||||
|
||||
int dm_sm_metadata_create(struct dm_space_map *sm,
|
||||
struct dm_transaction_manager *tm,
|
||||
dm_block_t nr_blocks,
|
||||
dm_block_t superblock)
|
||||
{
|
||||
int r;
|
||||
dm_block_t i;
|
||||
enum allocation_event ev;
|
||||
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
|
||||
|
||||
smm->begin = superblock + 1;
|
||||
smm->recursion_count = 0;
|
||||
smm->allocated_this_transaction = 0;
|
||||
smm->nr_uncommitted = 0;
|
||||
|
||||
memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
|
||||
|
||||
r = sm_ll_new_metadata(&smm->ll, tm);
|
||||
if (r)
|
||||
return r;
|
||||
|
||||
r = sm_ll_extend(&smm->ll, nr_blocks);
|
||||
if (r)
|
||||
return r;
|
||||
|
||||
memcpy(&smm->sm, &ops, sizeof(smm->sm));
|
||||
|
||||
/*
|
||||
* Now we need to update the newly created data structures with the
|
||||
* allocated blocks that they were built from.
|
||||
*/
|
||||
for (i = superblock; !r && i < smm->begin; i++)
|
||||
r = sm_ll_inc(&smm->ll, i, &ev);
|
||||
|
||||
if (r)
|
||||
return r;
|
||||
|
||||
return sm_metadata_commit(sm);
|
||||
}
|
||||
|
||||
int dm_sm_metadata_open(struct dm_space_map *sm,
|
||||
struct dm_transaction_manager *tm,
|
||||
void *root_le, size_t len)
|
||||
{
|
||||
int r;
|
||||
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
|
||||
|
||||
r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
|
||||
if (r)
|
||||
return r;
|
||||
|
||||
smm->begin = 0;
|
||||
smm->recursion_count = 0;
|
||||
smm->allocated_this_transaction = 0;
|
||||
smm->nr_uncommitted = 0;
|
||||
|
||||
memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
|
||||
return 0;
|
||||
}
|
||||
Reference in New Issue
Block a user