1 files changed, 446 insertions, 0 deletions

diff --git a/drivers/md/persistent-data/dm-space-map-checker.c b/drivers/md/persistent-data/dm-space-map-checker.c
new file mode 100644
index 00000000..fc90c116
--- /dev/null
+++ b/drivers/md/persistent-data/dm-space-map-checker.c
@@ -0,0 +1,446 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-space-map-checker.h"
+
+#include <linux/device-mapper.h>
+#include <linux/export.h>
+#include <linux/vmalloc.h>
+
+#ifdef CONFIG_DM_DEBUG_SPACE_MAPS
+
+#define DM_MSG_PREFIX "space map checker"
+
+/*----------------------------------------------------------------*/
+
+struct count_array {
+	dm_block_t nr;
+	dm_block_t nr_free;
+
+	uint32_t *counts;
+};
+
+static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count)
+{
+	if (b >= ca->nr)
+		return -EINVAL;
+
+	*count = ca->counts[b];
+	return 0;
+}
+
+static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r)
+{
+	if (b >= ca->nr)
+		return -EINVAL;
+
+	*r = ca->counts[b] > 1;
+	return 0;
+}
+
+static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count)
+{
+	uint32_t old_count;
+
+	if (b >= ca->nr)
+		return -EINVAL;
+
+	old_count = ca->counts[b];
+
+	if (!count && old_count)
+		ca->nr_free++;
+
+	else if (count && !old_count)
+		ca->nr_free--;
+
+	ca->counts[b] = count;
+	return 0;
+}
+
+static int ca_inc_block(struct count_array *ca, dm_block_t b)
+{
+	if (b >= ca->nr)
+		return -EINVAL;
+
+	ca_set_count(ca, b, ca->counts[b] + 1);
+	return 0;
+}
+
+static int ca_dec_block(struct count_array *ca, dm_block_t b)
+{
+	if (b >= ca->nr)
+		return -EINVAL;
+
+	BUG_ON(ca->counts[b] == 0);
+	ca_set_count(ca, b, ca->counts[b] - 1);
+	return 0;
+}
+
+static int ca_create(struct count_array *ca, struct dm_space_map *sm)
+{
+	int r;
+	dm_block_t nr_blocks;
+
+	r = dm_sm_get_nr_blocks(sm, &nr_blocks);
+	if (r)
+		return r;
+
+	ca->nr = nr_blocks;
+	ca->nr_free = nr_blocks;
+
+	if (!nr_blocks)
+		ca->counts = NULL;
+	else {
+		ca->counts = vzalloc(sizeof(*ca->counts) * nr_blocks);
+		if (!ca->counts)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void ca_destroy(struct count_array *ca)
+{
+	vfree(ca->counts);
+}
+
+static int ca_load(struct count_array *ca, struct dm_space_map *sm)
+{
+	int r;
+	uint32_t count;
+	dm_block_t nr_blocks, i;
+
+	r = dm_sm_get_nr_blocks(sm, &nr_blocks);
+	if (r)
+		return r;
+
+	BUG_ON(ca->nr != nr_blocks);
+
+	DMWARN("Loading debug space map from disk.  This may take some time");
+	for (i = 0; i < nr_blocks; i++) {
+		r = dm_sm_get_count(sm, i, &count);
+		if (r) {
+			DMERR("load failed");
+			return r;
+		}
+
+		ca_set_count(ca, i, count);
+	}
+	DMWARN("Load complete");
+
+	return 0;
+}
+
+static int ca_extend(struct count_array *ca, dm_block_t extra_blocks)
+{
+	dm_block_t nr_blocks = ca->nr + extra_blocks;
+	uint32_t *counts = vzalloc(sizeof(*counts) * nr_blocks);
+	if (!counts)
+		return -ENOMEM;
+
+	if (ca->counts) {
+		memcpy(counts, ca->counts, sizeof(*counts) * ca->nr);
+		ca_destroy(ca);
+	}
+	ca->nr = nr_blocks;
+	ca->nr_free += extra_blocks;
+	ca->counts = counts;
+	return 0;
+}
+
+static int ca_commit(struct count_array *old, struct count_array *new)
+{
+	if (old->nr != new->nr) {
+		BUG_ON(old->nr > new->nr);
+		ca_extend(old, new->nr - old->nr);
+	}
+
+	BUG_ON(old->nr != new->nr);
+	old->nr_free = new->nr_free;
+	memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr);
+	return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+struct sm_checker {
+	struct dm_space_map sm;
+
+	struct count_array old_counts;
+	struct count_array counts;
+
+	struct dm_space_map *real_sm;
+};
+
+static void sm_checker_destroy(struct dm_space_map *sm)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+
+	dm_sm_destroy(smc->real_sm);
+	ca_destroy(&smc->old_counts);
+	ca_destroy(&smc->counts);
+	kfree(smc);
+}
+
+static int sm_checker_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_get_nr_blocks(smc->real_sm, count);
+	if (!r)
+		BUG_ON(smc->old_counts.nr != *count);
+	return r;
+}
+
+static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_get_nr_free(smc->real_sm, count);
+	if (!r) {
+		/*
+		 * Slow, but we know it's correct.
+		 */
+		dm_block_t b, n = 0;
+		for (b = 0; b < smc->old_counts.nr; b++)
+			if (smc->old_counts.counts[b] == 0 &&
+			    smc->counts.counts[b] == 0)
+				n++;
+
+		if (n != *count)
+			DMERR("free block counts differ, checker %u, sm-disk:%u",
+			      (unsigned) n, (unsigned) *count);
+	}
+	return r;
+}
+
+static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_new_block(smc->real_sm, b);
+
+	if (!r) {
+		BUG_ON(*b >= smc->old_counts.nr);
+		BUG_ON(smc->old_counts.counts[*b] != 0);
+		BUG_ON(*b >= smc->counts.nr);
+		BUG_ON(smc->counts.counts[*b] != 0);
+		ca_set_count(&smc->counts, *b, 1);
+	}
+
+	return r;
+}
+
+static int sm_checker_inc_block(struct dm_space_map *sm, dm_block_t b)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_inc_block(smc->real_sm, b);
+	int r2 = ca_inc_block(&smc->counts, b);
+	BUG_ON(r != r2);
+	return r;
+}
+
+static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_dec_block(smc->real_sm, b);
+	int r2 = ca_dec_block(&smc->counts, b);
+	BUG_ON(r != r2);
+	return r;
+}
+
+static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	uint32_t result2 = 0;
+	int r = dm_sm_get_count(smc->real_sm, b, result);
+	int r2 = ca_get_count(&smc->counts, b, &result2);
+
+	BUG_ON(r != r2);
+	if (!r)
+		BUG_ON(*result != result2);
+	return r;
+}
+
+static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int result2 = 0;
+	int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result);
+	int r2 = ca_count_more_than_one(&smc->counts, b, &result2);
+
+	BUG_ON(r != r2);
+	if (!r)
+		BUG_ON(!(*result) && result2);
+	return r;
+}
+
+static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	uint32_t old_rc;
+	int r = dm_sm_set_count(smc->real_sm, b, count);
+	int r2;
+
+	BUG_ON(b >= smc->counts.nr);
+	old_rc = smc->counts.counts[b];
+	r2 = ca_set_count(&smc->counts, b, count);
+	BUG_ON(r != r2);
+
+	return r;
+}
+
+static int sm_checker_commit(struct dm_space_map *sm)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r;
+
+	r = dm_sm_commit(smc->real_sm);
+	if (r)
+		return r;
+
+	r = ca_commit(&smc->old_counts, &smc->counts);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	int r = dm_sm_extend(smc->real_sm, extra_blocks);
+	if (r)
+		return r;
+
+	return ca_extend(&smc->counts, extra_blocks);
+}
+
+static int sm_checker_root_size(struct dm_space_map *sm, size_t *result)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	return dm_sm_root_size(smc->real_sm, result);
+}
+
+static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len)
+{
+	struct sm_checker *smc = container_of(sm, struct sm_checker, sm);
+	return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len);
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_space_map ops_ = {
+	.destroy = sm_checker_destroy,
+	.get_nr_blocks = sm_checker_get_nr_blocks,
+	.get_nr_free = sm_checker_get_nr_free,
+	.inc_block = sm_checker_inc_block,
+	.dec_block = sm_checker_dec_block,
+	.new_block = sm_checker_new_block,
+	.get_count = sm_checker_get_count,
+	.count_is_more_than_one = sm_checker_count_more_than_one,
+	.set_count = sm_checker_set_count,
+	.commit = sm_checker_commit,
+	.extend = sm_checker_extend,
+	.root_size = sm_checker_root_size,
+	.copy_root = sm_checker_copy_root
+};
+
+struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
+{
+	int r;
+	struct sm_checker *smc;
+
+	if (IS_ERR_OR_NULL(sm))
+		return ERR_PTR(-EINVAL);
+
+	smc = kmalloc(sizeof(*smc), GFP_KERNEL);
+	if (!smc)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&smc->sm, &ops_, sizeof(smc->sm));
+	r = ca_create(&smc->old_counts, sm);
+	if (r) {
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	r = ca_create(&smc->counts, sm);
+	if (r) {
+		ca_destroy(&smc->old_counts);
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	smc->real_sm = sm;
+
+	r = ca_load(&smc->counts, sm);
+	if (r) {
+		ca_destroy(&smc->counts);
+		ca_destroy(&smc->old_counts);
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	r = ca_commit(&smc->old_counts, &smc->counts);
+	if (r) {
+		ca_destroy(&smc->counts);
+		ca_destroy(&smc->old_counts);
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	return &smc->sm;
+}
+EXPORT_SYMBOL_GPL(dm_sm_checker_create);
+
+struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
+{
+	int r;
+	struct sm_checker *smc;
+
+	if (IS_ERR_OR_NULL(sm))
+		return ERR_PTR(-EINVAL);
+
+	smc = kmalloc(sizeof(*smc), GFP_KERNEL);
+	if (!smc)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&smc->sm, &ops_, sizeof(smc->sm));
+	r = ca_create(&smc->old_counts, sm);
+	if (r) {
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	r = ca_create(&smc->counts, sm);
+	if (r) {
+		ca_destroy(&smc->old_counts);
+		kfree(smc);
+		return ERR_PTR(r);
+	}
+
+	smc->real_sm = sm;
+	return &smc->sm;
+}
+EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
+
+/*----------------------------------------------------------------*/
+
+#else
+
+struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm)
+{
+	return sm;
+}
+EXPORT_SYMBOL_GPL(dm_sm_checker_create);
+
+struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm)
+{
+	return sm;
+}
+EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh);
+
+/*----------------------------------------------------------------*/
+
+#endif