1/*
  2 * Copyright (C) 2012 Red Hat, Inc.
  3 *
  4 * This file is released under the GPL.
  5 */
  6
  7#include "dm-bitset.h"
  8#include "dm-transaction-manager.h"
  9
 10#include <linux/export.h>
 11#include <linux/device-mapper.h>
 12
 13#define DM_MSG_PREFIX "bitset"
 14#define BITS_PER_ARRAY_ENTRY 64
 15
 16/*----------------------------------------------------------------*/
 17
 18static struct dm_btree_value_type bitset_bvt = {
 19	.context = NULL,
 20	.size = sizeof(__le64),
 21	.inc = NULL,
 22	.dec = NULL,
 23	.equal = NULL,
 24};
 25
 26/*----------------------------------------------------------------*/
 27
 28void dm_disk_bitset_init(struct dm_transaction_manager *tm,
 29			 struct dm_disk_bitset *info)
 30{
 31	dm_array_info_init(&info->array_info, tm, &bitset_bvt);
 32	info->current_index_set = false;
 33}
 34EXPORT_SYMBOL_GPL(dm_disk_bitset_init);
 35
 36int dm_bitset_empty(struct dm_disk_bitset *info, dm_block_t *root)
 37{
 38	return dm_array_empty(&info->array_info, root);
 39}
 40EXPORT_SYMBOL_GPL(dm_bitset_empty);
 41
 42int dm_bitset_resize(struct dm_disk_bitset *info, dm_block_t root,
 43		     uint32_t old_nr_entries, uint32_t new_nr_entries,
 44		     bool default_value, dm_block_t *new_root)
 45{
 46	uint32_t old_blocks = dm_div_up(old_nr_entries, BITS_PER_ARRAY_ENTRY);
 47	uint32_t new_blocks = dm_div_up(new_nr_entries, BITS_PER_ARRAY_ENTRY);
 48	__le64 value = default_value ? cpu_to_le64(~0) : cpu_to_le64(0);
 49
 50	__dm_bless_for_disk(&value);
 51	return dm_array_resize(&info->array_info, root, old_blocks, new_blocks,
 52			       &value, new_root);
 53}
 54EXPORT_SYMBOL_GPL(dm_bitset_resize);
 55
 56int dm_bitset_del(struct dm_disk_bitset *info, dm_block_t root)
 57{
 58	return dm_array_del(&info->array_info, root);
 59}
 60EXPORT_SYMBOL_GPL(dm_bitset_del);
 61
 62int dm_bitset_flush(struct dm_disk_bitset *info, dm_block_t root,
 63		    dm_block_t *new_root)
 64{
 65	int r;
 66	__le64 value;
 67
 68	if (!info->current_index_set || !info->dirty)
 69		return 0;
 70
 71	value = cpu_to_le64(info->current_bits);
 72
 73	__dm_bless_for_disk(&value);
 74	r = dm_array_set_value(&info->array_info, root, info->current_index,
 75			       &value, new_root);
 76	if (r)
 77		return r;
 78
 79	info->current_index_set = false;
 80	info->dirty = false;
 81
 82	return 0;
 83}
 84EXPORT_SYMBOL_GPL(dm_bitset_flush);
 85
 86static int read_bits(struct dm_disk_bitset *info, dm_block_t root,
 87		     uint32_t array_index)
 88{
 89	int r;
 90	__le64 value;
 91
 92	r = dm_array_get_value(&info->array_info, root, array_index, &value);
 93	if (r)
 94		return r;
 95
 96	info->current_bits = le64_to_cpu(value);
 97	info->current_index_set = true;
 98	info->current_index = array_index;
 99	info->dirty = false;
100
101	return 0;
102}
103
104static int get_array_entry(struct dm_disk_bitset *info, dm_block_t root,
105			   uint32_t index, dm_block_t *new_root)
106{
107	int r;
108	unsigned array_index = index / BITS_PER_ARRAY_ENTRY;
109
110	if (info->current_index_set) {
111		if (info->current_index == array_index)
112			return 0;
113
114		r = dm_bitset_flush(info, root, new_root);
115		if (r)
116			return r;
117	}
118
119	return read_bits(info, root, array_index);
120}
121
122int dm_bitset_set_bit(struct dm_disk_bitset *info, dm_block_t root,
123		      uint32_t index, dm_block_t *new_root)
124{
125	int r;
126	unsigned b = index % BITS_PER_ARRAY_ENTRY;
127
128	r = get_array_entry(info, root, index, new_root);
129	if (r)
130		return r;
131
132	set_bit(b, (unsigned long *) &info->current_bits);
133	info->dirty = true;
134
135	return 0;
136}
137EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
138
139int dm_bitset_clear_bit(struct dm_disk_bitset *info, dm_block_t root,
140			uint32_t index, dm_block_t *new_root)
141{
142	int r;
143	unsigned b = index % BITS_PER_ARRAY_ENTRY;
144
145	r = get_array_entry(info, root, index, new_root);
146	if (r)
147		return r;
148
149	clear_bit(b, (unsigned long *) &info->current_bits);
150	info->dirty = true;
151
152	return 0;
153}
154EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
155
156int dm_bitset_test_bit(struct dm_disk_bitset *info, dm_block_t root,
157		       uint32_t index, dm_block_t *new_root, bool *result)
158{
159	int r;
160	unsigned b = index % BITS_PER_ARRAY_ENTRY;
161
162	r = get_array_entry(info, root, index, new_root);
163	if (r)
164		return r;
165
166	*result = test_bit(b, (unsigned long *) &info->current_bits);
167	return 0;
168}
169EXPORT_SYMBOL_GPL(dm_bitset_test_bit);
170
171/*----------------------------------------------------------------*/