1 files changed, 400 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
new file mode 100644
index 00000000000..728e89a3f97
--- /dev/null
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -0,0 +1,400 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+#include "dm-transaction-manager.h"
+#include "dm-space-map.h"
+#include "dm-space-map-checker.h"
+#include "dm-space-map-disk.h"
+#include "dm-space-map-metadata.h"
+#include "dm-persistent-data-internal.h"
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "transaction manager"
+
+/*----------------------------------------------------------------*/
+
+struct shadow_info {
+	struct hlist_node hlist;
+	dm_block_t where;
+};
+
+/*
+ * It would be nice if we scaled with the size of transaction.
+ */
+#define HASH_SIZE 256
+#define HASH_MASK (HASH_SIZE - 1)
+
+struct dm_transaction_manager {
+	int is_clone;
+	struct dm_transaction_manager *real;
+
+	struct dm_block_manager *bm;
+	struct dm_space_map *sm;
+
+	spinlock_t lock;
+	struct hlist_head buckets[HASH_SIZE];
+};
+
+/*----------------------------------------------------------------*/
+
+static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
+{
+	int r = 0;
+	unsigned bucket = dm_hash_block(b, HASH_MASK);
+	struct shadow_info *si;
+	struct hlist_node *n;
+
+	spin_lock(&tm->lock);
+	hlist_for_each_entry(si, n, tm->buckets + bucket, hlist)
+		if (si->where == b) {
+			r = 1;
+			break;
+		}
+	spin_unlock(&tm->lock);
+
+	return r;
+}
+
+/*
+ * This can silently fail if there's no memory.  We're ok with this since
+ * creating redundant shadows causes no harm.
+ */
+static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
+{
+	unsigned bucket;
+	struct shadow_info *si;
+
+	si = kmalloc(sizeof(*si), GFP_NOIO);
+	if (si) {
+		si->where = b;
+		bucket = dm_hash_block(b, HASH_MASK);
+		spin_lock(&tm->lock);
+		hlist_add_head(&si->hlist, tm->buckets + bucket);
+		spin_unlock(&tm->lock);
+	}
+}
+
+static void wipe_shadow_table(struct dm_transaction_manager *tm)
+{
+	struct shadow_info *si;
+	struct hlist_node *n, *tmp;
+	struct hlist_head *bucket;
+	int i;
+
+	spin_lock(&tm->lock);
+	for (i = 0; i < HASH_SIZE; i++) {
+		bucket = tm->buckets + i;
+		hlist_for_each_entry_safe(si, n, tmp, bucket, hlist)
+			kfree(si);
+
+		INIT_HLIST_HEAD(bucket);
+	}
+
+	spin_unlock(&tm->lock);
+}
+
+/*----------------------------------------------------------------*/
+
+static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
+						   struct dm_space_map *sm)
+{
+	int i;
+	struct dm_transaction_manager *tm;
+
+	tm = kmalloc(sizeof(*tm), GFP_KERNEL);
+	if (!tm)
+		return ERR_PTR(-ENOMEM);
+
+	tm->is_clone = 0;
+	tm->real = NULL;
+	tm->bm = bm;
+	tm->sm = sm;
+
+	spin_lock_init(&tm->lock);
+	for (i = 0; i < HASH_SIZE; i++)
+		INIT_HLIST_HEAD(tm->buckets + i);
+
+	return tm;
+}
+
+struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real)
+{
+	struct dm_transaction_manager *tm;
+
+	tm = kmalloc(sizeof(*tm), GFP_KERNEL);
+	if (tm) {
+		tm->is_clone = 1;
+		tm->real = real;
+	}
+
+	return tm;
+}
+EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone);
+
+void dm_tm_destroy(struct dm_transaction_manager *tm)
+{
+	kfree(tm);
+}
+EXPORT_SYMBOL_GPL(dm_tm_destroy);
+
+int dm_tm_pre_commit(struct dm_transaction_manager *tm)
+{
+	int r;
+
+	if (tm->is_clone)
+		return -EWOULDBLOCK;
+
+	r = dm_sm_commit(tm->sm);
+	if (r < 0)
+		return r;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
+
+int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
+{
+	if (tm->is_clone)
+		return -EWOULDBLOCK;
+
+	wipe_shadow_table(tm);
+
+	return dm_bm_flush_and_unlock(tm->bm, root);
+}
+EXPORT_SYMBOL_GPL(dm_tm_commit);
+
+int dm_tm_new_block(struct dm_transaction_manager *tm,
+		    struct dm_block_validator *v,
+		    struct dm_block **result)
+{
+	int r;
+	dm_block_t new_block;
+
+	if (tm->is_clone)
+		return -EWOULDBLOCK;
+
+	r = dm_sm_new_block(tm->sm, &new_block);
+	if (r < 0)
+		return r;
+
+	r = dm_bm_write_lock_zero(tm->bm, new_block, v, result);
+	if (r < 0) {
+		dm_sm_dec_block(tm->sm, new_block);
+		return r;
+	}
+
+	/*
+	 * New blocks count as shadows in that they don't need to be
+	 * shadowed again.
+	 */
+	insert_shadow(tm, new_block);
+
+	return 0;
+}
+
+static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
+			  struct dm_block_validator *v,
+			  struct dm_block **result)
+{
+	int r;
+	dm_block_t new;
+	struct dm_block *orig_block;
+
+	r = dm_sm_new_block(tm->sm, &new);
+	if (r < 0)
+		return r;
+
+	r = dm_sm_dec_block(tm->sm, orig);
+	if (r < 0)
+		return r;
+
+	r = dm_bm_read_lock(tm->bm, orig, v, &orig_block);
+	if (r < 0)
+		return r;
+
+	r = dm_bm_unlock_move(orig_block, new);
+	if (r < 0) {
+		dm_bm_unlock(orig_block);
+		return r;
+	}
+
+	return dm_bm_write_lock(tm->bm, new, v, result);
+}
+
+int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
+		       struct dm_block_validator *v, struct dm_block **result,
+		       int *inc_children)
+{
+	int r;
+
+	if (tm->is_clone)
+		return -EWOULDBLOCK;
+
+	r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children);
+	if (r < 0)
+		return r;
+
+	if (is_shadow(tm, orig) && !*inc_children)
+		return dm_bm_write_lock(tm->bm, orig, v, result);
+
+	r = __shadow_block(tm, orig, v, result);
+	if (r < 0)
+		return r;
+	insert_shadow(tm, dm_block_location(*result));
+
+	return r;
+}
+
+int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
+		    struct dm_block_validator *v,
+		    struct dm_block **blk)
+{
+	if (tm->is_clone)
+		return dm_bm_read_try_lock(tm->real->bm, b, v, blk);
+
+	return dm_bm_read_lock(tm->bm, b, v, blk);
+}
+
+int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
+{
+	return dm_bm_unlock(b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_unlock);
+
+void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
+{
+	/*
+	 * The non-blocking clone doesn't support this.
+	 */
+	BUG_ON(tm->is_clone);
+
+	dm_sm_inc_block(tm->sm, b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_inc);
+
+void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b)
+{
+	/*
+	 * The non-blocking clone doesn't support this.
+	 */
+	BUG_ON(tm->is_clone);
+
+	dm_sm_dec_block(tm->sm, b);
+}
+EXPORT_SYMBOL_GPL(dm_tm_dec);
+
+int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
+	      uint32_t *result)
+{
+	if (tm->is_clone)
+		return -EWOULDBLOCK;
+
+	return dm_sm_get_count(tm->sm, b, result);
+}
+
+struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
+{
+	return tm->bm;
+}
+
+/*----------------------------------------------------------------*/
+
+static int dm_tm_create_internal(struct dm_block_manager *bm,
+				 dm_block_t sb_location,
+				 struct dm_block_validator *sb_validator,
+				 size_t root_offset, size_t root_max_len,
+				 struct dm_transaction_manager **tm,
+				 struct dm_space_map **sm,
+				 struct dm_block **sblock,
+				 int create)
+{
+	int r;
+	struct dm_space_map *inner;
+
+	inner = dm_sm_metadata_init();
+	if (IS_ERR(inner))
+		return PTR_ERR(inner);
+
+	*tm = dm_tm_create(bm, inner);
+	if (IS_ERR(*tm)) {
+		dm_sm_destroy(inner);
+		return PTR_ERR(*tm);
+	}
+
+	if (create) {
+		r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location,
+					  sb_validator, sblock);
+		if (r < 0) {
+			DMERR("couldn't lock superblock");
+			goto bad1;
+		}
+
+		r = dm_sm_metadata_create(inner, *tm, dm_bm_nr_blocks(bm),
+					  sb_location);
+		if (r) {
+			DMERR("couldn't create metadata space map");
+			goto bad2;
+		}
+
+		*sm = dm_sm_checker_create(inner);
+		if (!*sm)
+			goto bad2;
+
+	} else {
+		r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location,
+				     sb_validator, sblock);
+		if (r < 0) {
+			DMERR("couldn't lock superblock");
+			goto bad1;
+		}
+
+		r = dm_sm_metadata_open(inner, *tm,
+					dm_block_data(*sblock) + root_offset,
+					root_max_len);
+		if (r) {
+			DMERR("couldn't open metadata space map");
+			goto bad2;
+		}
+
+		*sm = dm_sm_checker_create(inner);
+		if (!*sm)
+			goto bad2;
+	}
+
+	return 0;
+
+bad2:
+	dm_tm_unlock(*tm, *sblock);
+bad1:
+	dm_tm_destroy(*tm);
+	dm_sm_destroy(inner);
+	return r;
+}
+
+int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+			 struct dm_block_validator *sb_validator,
+			 struct dm_transaction_manager **tm,
+			 struct dm_space_map **sm, struct dm_block **sblock)
+{
+	return dm_tm_create_internal(bm, sb_location, sb_validator,
+				     0, 0, tm, sm, sblock, 1);
+}
+EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
+
+int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
+		       struct dm_block_validator *sb_validator,
+		       size_t root_offset, size_t root_max_len,
+		       struct dm_transaction_manager **tm,
+		       struct dm_space_map **sm, struct dm_block **sblock)
+{
+	return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset,
+				     root_max_len, tm, sm, sblock, 0);
+}
+EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
+
+/*----------------------------------------------------------------*/