drivers/md/persistent-data/dm-transaction-manager.c - linux - Git at Google

 /*
  * 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/export.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;
 }
 EXPORT_SYMBOL_GPL(dm_tm_shadow_block);

 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);
 }
 EXPORT_SYMBOL_GPL(dm_tm_read_lock);

 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);

 /*----------------------------------------------------------------*/
	/*
	* 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/export.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;
	}
	EXPORT_SYMBOL_GPL(dm_tm_shadow_block);

	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);
	}
	EXPORT_SYMBOL_GPL(dm_tm_read_lock);

	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);

	/----------------------------------------------------------------/