40c57f475f
Don't waste time spotting blocks that have been allocated and then freed in the same transaction. The extra lookup is expensive, and I don't think it really gives us much. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
303 lines
6.3 KiB
C
303 lines
6.3 KiB
C
/*
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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-common.h"
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#include "dm-space-map-disk.h"
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#include "dm-space-map.h"
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#include "dm-transaction-manager.h"
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/device-mapper.h>
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#define DM_MSG_PREFIX "space map disk"
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/*----------------------------------------------------------------*/
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/*
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* Space map interface.
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*/
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struct sm_disk {
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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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dm_block_t nr_allocated_this_transaction;
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};
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static void sm_disk_destroy(struct dm_space_map *sm)
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{
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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kfree(smd);
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}
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static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
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{
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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return sm_ll_extend(&smd->ll, extra_blocks);
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}
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static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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*count = smd->old_ll.nr_blocks;
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return 0;
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}
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static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
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{
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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*count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
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return 0;
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}
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static int sm_disk_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_disk *smd = container_of(sm, struct sm_disk, sm);
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return sm_ll_lookup(&smd->ll, b, result);
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}
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static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
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int *result)
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{
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int r;
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uint32_t count;
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r = sm_disk_get_count(sm, b, &count);
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if (r)
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return r;
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return count > 1;
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}
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static int sm_disk_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;
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uint32_t old_count;
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enum allocation_event ev;
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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r = sm_ll_insert(&smd->ll, b, count, &ev);
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if (!r) {
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switch (ev) {
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case SM_NONE:
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break;
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case SM_ALLOC:
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/*
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* This _must_ be free in the prior transaction
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* otherwise we've lost atomicity.
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*/
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smd->nr_allocated_this_transaction++;
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break;
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case SM_FREE:
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/*
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* It's only free if it's also free in the last
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* transaction.
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*/
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r = sm_ll_lookup(&smd->old_ll, b, &old_count);
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if (r)
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return r;
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if (!old_count)
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smd->nr_allocated_this_transaction--;
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break;
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}
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}
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return r;
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}
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static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
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{
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int r;
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enum allocation_event ev;
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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r = sm_ll_inc(&smd->ll, b, &ev);
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if (!r && (ev == SM_ALLOC))
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/*
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* This _must_ be free in the prior transaction
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* otherwise we've lost atomicity.
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*/
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smd->nr_allocated_this_transaction++;
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return r;
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}
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static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
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{
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enum allocation_event ev;
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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return sm_ll_dec(&smd->ll, b, &ev);
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}
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static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
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{
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int r;
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enum allocation_event ev;
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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/* FIXME: we should loop round a couple of times */
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r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
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if (r)
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return r;
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smd->begin = *b + 1;
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r = sm_ll_inc(&smd->ll, *b, &ev);
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if (!r) {
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BUG_ON(ev != SM_ALLOC);
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smd->nr_allocated_this_transaction++;
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}
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return r;
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}
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static int sm_disk_commit(struct dm_space_map *sm)
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{
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int r;
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dm_block_t nr_free;
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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r = sm_disk_get_nr_free(sm, &nr_free);
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if (r)
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return r;
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r = sm_ll_commit(&smd->ll);
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if (r)
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return r;
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memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
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smd->begin = 0;
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smd->nr_allocated_this_transaction = 0;
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r = sm_disk_get_nr_free(sm, &nr_free);
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if (r)
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return r;
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return 0;
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}
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static int sm_disk_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_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
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{
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struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
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struct disk_sm_root root_le;
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root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
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root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
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root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
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root_le.ref_count_root = cpu_to_le64(smd->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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/*----------------------------------------------------------------*/
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static struct dm_space_map ops = {
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.destroy = sm_disk_destroy,
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.extend = sm_disk_extend,
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.get_nr_blocks = sm_disk_get_nr_blocks,
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.get_nr_free = sm_disk_get_nr_free,
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.get_count = sm_disk_get_count,
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.count_is_more_than_one = sm_disk_count_is_more_than_one,
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.set_count = sm_disk_set_count,
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.inc_block = sm_disk_inc_block,
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.dec_block = sm_disk_dec_block,
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.new_block = sm_disk_new_block,
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.commit = sm_disk_commit,
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.root_size = sm_disk_root_size,
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.copy_root = sm_disk_copy_root,
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.register_threshold_callback = NULL
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};
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struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
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dm_block_t nr_blocks)
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{
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int r;
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struct sm_disk *smd;
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smd = kmalloc(sizeof(*smd), GFP_KERNEL);
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if (!smd)
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return ERR_PTR(-ENOMEM);
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smd->begin = 0;
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smd->nr_allocated_this_transaction = 0;
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memcpy(&smd->sm, &ops, sizeof(smd->sm));
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r = sm_ll_new_disk(&smd->ll, tm);
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if (r)
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goto bad;
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r = sm_ll_extend(&smd->ll, nr_blocks);
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if (r)
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goto bad;
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r = sm_disk_commit(&smd->sm);
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if (r)
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goto bad;
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return &smd->sm;
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bad:
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kfree(smd);
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return ERR_PTR(r);
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}
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EXPORT_SYMBOL_GPL(dm_sm_disk_create);
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struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
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void *root_le, size_t len)
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{
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int r;
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struct sm_disk *smd;
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smd = kmalloc(sizeof(*smd), GFP_KERNEL);
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if (!smd)
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return ERR_PTR(-ENOMEM);
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smd->begin = 0;
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smd->nr_allocated_this_transaction = 0;
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memcpy(&smd->sm, &ops, sizeof(smd->sm));
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r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
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if (r)
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goto bad;
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r = sm_disk_commit(&smd->sm);
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if (r)
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goto bad;
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return &smd->sm;
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bad:
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kfree(smd);
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return ERR_PTR(r);
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}
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EXPORT_SYMBOL_GPL(dm_sm_disk_open);
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/*----------------------------------------------------------------*/
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