The Copy-on-Write B-tree backend uses device-mapper's presistend-data
library to store Dmdedup's metadata. Currently, a B-tree is used for
both linear and sparse mappings. As the key size is limited to 64 bits
in the persistent-data library, we use linear probing if a collision
occurs.
Signed-off-by: Vasily Tarasov <tarasov@xxxxxxxxxxx>
---
drivers/md/dm-dedup-cbt.c | 755 +++++++++++++++++++++++++++++++++++++++++++++
drivers/md/dm-dedup-cbt.h | 44 +++
2 files changed, 799 insertions(+), 0 deletions(-)
create mode 100644 drivers/md/dm-dedup-cbt.c
create mode 100644 drivers/md/dm-dedup-cbt.h
diff --git a/drivers/md/dm-dedup-cbt.c b/drivers/md/dm-dedup-cbt.c
new file mode 100644
index 0000000..f400e6e
--- /dev/null
+++ b/drivers/md/dm-dedup-cbt.c
@@ -0,0 +1,755 @@
+/*
+ * Copyright (C) 2012-2014 Vasily Tarasov
+ * Copyright (C) 2012-2014 Geoff Kuenning
+ * Copyright (C) 2012-2014 Sonam Mandal
+ * Copyright (C) 2012-2014 Karthikeyani Palanisami
+ * Copyright (C) 2012-2014 Philip Shilane
+ * Copyright (C) 2012-2014 Sagar Trehan
+ * Copyright (C) 2012-2014 Erez Zadok
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/errno.h>
+#include "persistent-data/dm-btree.h"
+#include "persistent-data/dm-space-map.h"
+#include "persistent-data/dm-space-map-disk.h"
+#include "persistent-data/dm-block-manager.h"
+#include "persistent-data/dm-transaction-manager.h"
+
+#include "dm-dedup-cbt.h"
+#include "dm-dedup-backend.h"
+#include "dm-dedup-kvstore.h"
+
+#define EMPTY_ENTRY -5
+#define DELETED_ENTRY -6
+
+#define UINT32_MAX (4294967295U)
+
+#define METADATA_BSIZE 4096
+#define METADATA_CACHESIZE 64 /* currently block manager ignores this value */
+#define METADATA_MAXLOCKS 5
+#define METADATA_SUPERBLOCK_LOCATION 0
+
+struct metadata {
+ struct dm_block_manager *meta_bm;
+ struct dm_transaction_manager *tm;
+ struct dm_space_map *data_sm;
+ struct dm_space_map *meta_sm;
+
+ /*
+ * XXX: Currently we support only one linear and one sparse KVS.
+ */
+ struct kvstore_cbt *kvs_linear;
+ struct kvstore_cbt *kvs_sparse;
+};
+
+struct kvstore_cbt {
+ struct kvstore ckvs;
+ uint32_t entry_size; /* for sparse only */
+
+ struct dm_btree_info info;
+ uint64_t root;
+};
+
+#define SPACE_MAP_ROOT_SIZE 128
+
+struct metadata_superblock {
+ __le32 csum; /* Checksum of superblock except for this field. */
+ __le32 flags; /* General purpose flags. Not used. */
+ __le64 blocknr; /* This block number, dm_block_t. */
+ __u8 uuid[16]; /* UUID of device (Not used) */
+ __le64 magic; /* Magic number to check against */
+ __le32 version; /* Metadata root version */
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];/* Metadata space
+ map */
+ __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE]; /* Data space map */
+ __le64 lbn_pbn_root; /* lbn pbn btree root. */
+ __le64 hash_pbn_root; /* hash pbn btree root. */
+ __le32 data_block_size; /* In bytes */
+ __le32 metadata_block_size; /* In bytes */
+ __le64 metadata_nr_blocks;/* Number of metadata blocks used. */
+} __packed;
+
+static int __begin_transaction(struct metadata *md)
+{
+ int r;
+ struct metadata_superblock *disk_super;
+ struct dm_block *sblock;
+
+ r = dm_bm_read_lock(md->meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ NULL, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+
+ if (md->kvs_linear)
+ md->kvs_linear->root = le64_to_cpu(disk_super->lbn_pbn_root);
+
+ if (md->kvs_sparse)
+ md->kvs_sparse->root = le64_to_cpu(disk_super->hash_pbn_root);
+
+ dm_bm_unlock(sblock);
+
+ return r;
+}
+
+static int __commit_transaction(struct metadata *md)
+{
+ int r = 0;
+ size_t metadata_len, data_len;
+ struct metadata_superblock *disk_super;
+ struct dm_block *sblock;
+
+ BUILD_BUG_ON(sizeof(struct metadata_superblock) > 512);
+
+ r = dm_sm_commit(md->data_sm);
+ if (r < 0)
+ goto out;
+
+ r = dm_tm_pre_commit(md->tm);
+ if (r < 0)
+ goto out;
+
+ r = dm_sm_root_size(md->meta_sm, &metadata_len);
+ if (r < 0)
+ goto out;
+
+ r = dm_sm_root_size(md->data_sm, &data_len);
+ if (r < 0)
+ goto out;
+
+ r = dm_bm_write_lock(md->meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ NULL, &sblock);
+ if (r)
+ goto out;
+
+ disk_super = dm_block_data(sblock);
+
+ if (md->kvs_linear)
+ disk_super->lbn_pbn_root = cpu_to_le64(md->kvs_linear->root);
+
+ if (md->kvs_sparse)
+ disk_super->hash_pbn_root = cpu_to_le64(md->kvs_sparse->root);
+
+ r = dm_sm_copy_root(md->meta_sm,
+ &disk_super->metadata_space_map_root, metadata_len);
+ if (r < 0)
+ goto out_locked;
+
+ r = dm_sm_copy_root(md->data_sm, &disk_super->data_space_map_root,
+ data_len);
+ if (r < 0)
+ goto out_locked;
+
+ r = dm_tm_commit(md->tm, sblock);
+
+out:
+ return r;
+
+out_locked:
+ dm_bm_unlock(sblock);
+ return r;
+}
+
+static int write_initial_superblock(struct metadata *md)
+{
+ int r;
+ size_t meta_len, data_len;
+ struct dm_block *sblock;
+ struct metadata_superblock *disk_super;
+
+ r = dm_sm_root_size(md->meta_sm, &meta_len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_root_size(md->data_sm, &data_len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_commit(md->data_sm);
+ if (r < 0)
+ return r;
+
+ r = dm_tm_pre_commit(md->tm);
+ if (r < 0)
+ return r;
+
+ r = dm_bm_write_lock_zero(md->meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ NULL, &sblock);
+ if (r < 0)
+ return r;
+
+ disk_super = dm_block_data(sblock);
+
+ r = dm_sm_copy_root(md->meta_sm, &disk_super->metadata_space_map_root,
+ meta_len);
+ if (r < 0)
+ goto bad_locked;
+
+ r = dm_sm_copy_root(md->data_sm, &disk_super->data_space_map_root,
+ data_len);
+ if (r < 0)
+ goto bad_locked;
+
+ return dm_tm_commit(md->tm, sblock);
+
+bad_locked:
+ dm_bm_unlock(sblock);
+ return r;
+}
+
+static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
+{
+ int r;
+ unsigned i;
+ struct dm_block *b;
+ __le64 *data_le, zero = cpu_to_le64(0);
+ unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
+
+ /*
+ * We can't use a validator here - it may be all zeroes.
+ */
+ r = dm_bm_read_lock(bm, METADATA_SUPERBLOCK_LOCATION, NULL, &b);
+ if (r)
+ return r;
+
+ data_le = dm_block_data(b);
+ *result = true;
+ for (i = 0; i < sb_block_size; i++) {
+ if (data_le[i] != zero) {
+ *result = false;
+ break;
+ }
+ }
+
+ return dm_bm_unlock(b);
+}
+
+static struct metadata *init_meta_cowbtree(void *input_param, bool *unformatted)
+{
+ int ret;
+ struct metadata *md;
+ struct dm_block_manager *meta_bm;
+ struct dm_space_map *meta_sm;
+ struct dm_space_map *data_sm = NULL;
+ struct dm_transaction_manager *tm;
+ struct init_param_cowbtree *p =
+ (struct init_param_cowbtree *)input_param;
+
+ DMINFO("Initializing COWBTREE backend");
+
+ md = kzalloc(sizeof(*md), GFP_NOIO);
+ if (!md)
+ return ERR_PTR(-ENOMEM);
+
+ meta_bm = dm_block_manager_create(p->metadata_bdev, METADATA_BSIZE,
+ METADATA_CACHESIZE, METADATA_MAXLOCKS);
+ if (IS_ERR(meta_bm)) {
+ md = (struct metadata *)meta_bm;
+ goto badbm;
+ }
+
+ ret = superblock_all_zeroes(meta_bm, unformatted);
+ if (ret) {
+ md = ERR_PTR(ret);
+ goto badtm;
+ }
+
+ if (!*unformatted) {
+ struct dm_block *sblock;
+ struct metadata_superblock *disk_super;
+
+ md->meta_bm = meta_bm;
+
+ ret = dm_bm_read_lock(meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ NULL, &sblock);
+ if (ret < 0) {
+ DMERR("could not read_lock superblock");
+ /* XXX: handle error */
+ }
+
+ disk_super = dm_block_data(sblock);
+
+ ret = dm_tm_open_with_sm(meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ disk_super->metadata_space_map_root,
+ sizeof(disk_super->metadata_space_map_root),
+ &md->tm, &md->meta_sm);
+ if (ret < 0) {
+ DMERR("could not open_with_sm superblock");
+ /* XXX: handle error */
+ }
+
+
+ md->data_sm = dm_sm_disk_open(md->tm,
+ disk_super->data_space_map_root,
+ sizeof(disk_super->data_space_map_root));
+ if (IS_ERR(md->data_sm)) {
+ DMERR("dm_disk_open failed");
+ /*XXX: handle error */
+ }
+
+ dm_bm_unlock(sblock);
+
+ goto begin_trans;
+ }
+
+ ret = dm_tm_create_with_sm(meta_bm, METADATA_SUPERBLOCK_LOCATION,
+ &tm, &meta_sm);
+ if (ret < 0) {
+ md = ERR_PTR(ret);
+ goto badtm;
+ }
+
+ data_sm = dm_sm_disk_create(tm, p->blocks);
+ if (IS_ERR(data_sm)) {
+ md = (struct metadata *)data_sm;
+ goto badsm;
+ }
+
+ md->meta_bm = meta_bm;
+ md->tm = tm;
+ md->meta_sm = meta_sm;
+ md->data_sm = data_sm;
+
+ ret = write_initial_superblock(md);
+ if (ret < 0) {
+ md = ERR_PTR(ret);
+ goto badwritesuper;
+ }
+
+begin_trans:
+ ret = __begin_transaction(md);
+ if (ret < 0) {
+ md = ERR_PTR(ret);
+ goto badwritesuper;
+ }
+
+ md->kvs_linear = NULL;
+ md->kvs_sparse = NULL;
+
+ return md;
+
+badwritesuper:
+ dm_sm_destroy(data_sm);
+badsm:
+ dm_tm_destroy(tm);
+ dm_sm_destroy(meta_sm);
+badtm:
+ dm_block_manager_destroy(meta_bm);
+badbm:
+ kfree(md);
+ return md;
+}
+
+static void exit_meta_cowbtree(struct metadata *md)
+{
+ int ret;
+
+ ret = __commit_transaction(md);
+ if (ret < 0)
+ DMWARN("%s: __commit_transaction() failed, error = %d.",
+ __func__, ret);
+
+ dm_sm_destroy(md->data_sm);
+ dm_tm_destroy(md->tm);
+ dm_sm_destroy(md->meta_sm);
+ dm_block_manager_destroy(md->meta_bm);
+
+ kfree(md->kvs_linear);
+ kfree(md->kvs_sparse);
+
+ kfree(md);
+}
+
+static int flush_meta_cowbtree(struct metadata *md)
+{
+ int r;
+
+ r = __commit_transaction(md);
+ if (r < 0)
+ return r;
+
+ r = __begin_transaction(md);
+
+ return r;
+}
+
+/********************************************************
+ * Space Management Functions *
+ ********************************************************/
+
+static int alloc_data_block_cowbtree(struct metadata *md, uint64_t *blockn)
+{
+
+ return dm_sm_new_block(md->data_sm, blockn);
+}
+
+static int inc_refcount_cowbtree(struct metadata *md, uint64_t blockn)
+{
+ return dm_sm_inc_block(md->data_sm, blockn);
+}
+
+static int dec_refcount_cowbtree(struct metadata *md, uint64_t blockn)
+{
+ return dm_sm_dec_block(md->data_sm, blockn);
+}
+
+static int get_refcount_cowbtree(struct metadata *md, uint64_t blockn)
+{
+ uint32_t refcount;
+ int r;
+
+ r = dm_sm_get_count(md->data_sm, blockn, &refcount);
+ if (r < 0)
+ return r;
+
+ return (int)refcount;
+}
+
+/*********************************************************
+ * Linear KVS Functions *
+ *********************************************************/
+
+static int kvs_delete_linear_cowbtree(struct kvstore *kvs,
+ void *key, int32_t ksize)
+{
+ int r;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ r = dm_btree_remove(&(kvcbt->info), kvcbt->root, key, &(kvcbt->root));
+
+ if (r == -ENODATA)
+ return -ENODEV;
+ else if (r >= 0)
+ return 0;
+
+ return r;
+}
+
+/*
+ * 0 - not found
+ * 1 - found
+ * < 0 - error on lookup
+ */
+static int kvs_lookup_linear_cowbtree(struct kvstore *kvs, void *key,
+ int32_t ksize, void *value, int32_t *vsize)
+{
+ int r;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ r = dm_btree_lookup(&(kvcbt->info), kvcbt->root, key, value);
+
+ if (r == -ENODATA)
+ return 0;
+ else if (r >= 0)
+ return 1;
+ else
+ return r;
+}
+
+static int kvs_insert_linear_cowbtree(struct kvstore *kvs, void *key,
+ int32_t ksize, void *value,
+ int32_t vsize)
+{
+ int inserted;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ if (vsize != kvs->vsize)
+ return -EINVAL;
+
+ return dm_btree_insert_notify(&(kvcbt->info), kvcbt->root, key,
+ value, &(kvcbt->root), &inserted);
+
+}
+
+static struct kvstore *kvs_create_linear_cowbtree(struct metadata *md,
+ uint32_t ksize, uint32_t vsize, uint32_t kmax,
+ bool unformatted)
+{
+ struct kvstore_cbt *kvs;
+ int r;
+
+ if (!vsize || !ksize)
+ return ERR_PTR(-ENOTSUPP);
+
+ /* Currently only 64bit keys are supported */
+ if (ksize != 8)
+ return ERR_PTR(-ENOTSUPP);
+
+ /* We do not support two or more KVSs at the moment */
+ if (md->kvs_linear)
+ return ERR_PTR(-EBUSY);
+
+ kvs = kmalloc(sizeof(*kvs), GFP_NOIO);
+ if (!kvs)
+ return ERR_PTR(-ENOMEM);
+
+ kvs->ckvs.ksize = ksize;
+ kvs->ckvs.vsize = vsize;
+
+ kvs->info.tm = md->tm;
+ kvs->info.levels = 1;
+ kvs->info.value_type.context = NULL;
+ kvs->info.value_type.size = vsize;
+ kvs->info.value_type.inc = NULL;
+ kvs->info.value_type.dec = NULL;
+ kvs->info.value_type.equal = NULL;
+
+ if (!unformatted) {
+ kvs->ckvs.kvs_insert = kvs_insert_linear_cowbtree;
+ kvs->ckvs.kvs_lookup = kvs_lookup_linear_cowbtree;
+ kvs->ckvs.kvs_delete = kvs_delete_linear_cowbtree;
+ kvs->ckvs.kvs_iterate = NULL;
+
+ md->kvs_linear = kvs;
+ __begin_transaction(md);
+ } else {
+ r = dm_btree_empty(&(kvs->info), &(kvs->root));
+ if (r < 0) {
+ kvs = ERR_PTR(r);
+ goto badtree;
+ }
+
+ /* I think this should be moved below the 4 lines below */
+ flush_meta_cowbtree(md);
+
+ kvs->ckvs.kvs_insert = kvs_insert_linear_cowbtree;
+ kvs->ckvs.kvs_lookup = kvs_lookup_linear_cowbtree;
+ kvs->ckvs.kvs_delete = kvs_delete_linear_cowbtree;
+ kvs->ckvs.kvs_iterate = NULL;
+
+ md->kvs_linear = kvs;
+ }
+
+ return &(kvs->ckvs);
+
+badtree:
+ kfree(kvs);
+ return (struct kvstore *) kvs;
+}
+
+/********************************************************
+ * Sparse KVS Functions *
+ ********************************************************/
+
+static int kvs_delete_sparse_cowbtree(struct kvstore *kvs,
+ void *key, int32_t ksize)
+{
+ char *entry;
+ uint64_t key_val;
+ int r;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ entry = kmalloc(kvcbt->entry_size, GFP_NOIO);
+ if (!entry)
+ return -ENOMEM;
+
+ key_val = (*(uint64_t *)key);
+
+repeat:
+
+ r = dm_btree_lookup(&(kvcbt->info), kvcbt->root, &key_val, entry);
+ if (r == -ENODATA)
+ return -ENODEV;
+ else if (r >= 0) {
+ if (!memcmp(entry, key, ksize)) {
+ r = dm_btree_remove(&(kvcbt->info),
+ kvcbt->root, &key_val, &(kvcbt->root));
+ kfree(entry);
+ return r;
+ }
+ key_val++;
+ goto repeat;
+ } else {
+ kfree(entry);
+ return r;
+ }
+}
+
+/*
+ * 0 - not found
+ * 1 - found
+ * < 0 - error on lookup
+ */
+static int kvs_lookup_sparse_cowbtree(struct kvstore *kvs, void *key,
+ int32_t ksize, void *value, int32_t *vsize)
+{
+ char *entry;
+ uint64_t key_val;
+ int r;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ entry = kmalloc(kvcbt->entry_size, GFP_NOIO);
+ if (!entry)
+ return -ENOMEM;
+
+ key_val = (*(uint64_t *)key);
+
+repeat:
+
+ r = dm_btree_lookup(&(kvcbt->info), kvcbt->root, &key_val, entry);
+ if (r == -ENODATA) {
+ kfree(entry);
+ return 0;
+ } else if (r >= 0) {
+ if (!memcmp(entry, key, ksize)) {
+ memcpy(value, entry + ksize, kvs->vsize);
+ kfree(entry);
+ return 1;
+ }
+ key_val++;
+ goto repeat;
+ } else {
+ kfree(entry);
+ return r;
+ }
+}
+
+static int kvs_insert_sparse_cowbtree(struct kvstore *kvs, void *key,
+ int32_t ksize, void *value,
+ int32_t vsize)
+{
+ char *entry;
+ uint64_t key_val;
+ int r;
+ struct kvstore_cbt *kvcbt = NULL;
+
+ kvcbt = container_of(kvs, struct kvstore_cbt, ckvs);
+
+ if (ksize != kvs->ksize)
+ return -EINVAL;
+
+ if (vsize != kvs->vsize)
+ return -EINVAL;
+
+ entry = kmalloc(kvcbt->entry_size, GFP_NOIO);
+ if (!entry)
+ return -ENOMEM;
+
+ key_val = (*(uint64_t *)key);
+
+
+repeat:
+
+ r = dm_btree_lookup(&(kvcbt->info), kvcbt->root, &key_val, entry);
+ if (r == -ENODATA) {
+ memcpy(entry, key, ksize);
+ memcpy(entry + ksize, value, vsize);
+ r = dm_btree_insert(&(kvcbt->info), kvcbt->root, &key_val,
+ entry, &(kvcbt->root));
+ kfree(entry);
+ return r;
+ } else if (r >= 0) {
+ key_val++;
+ goto repeat;
+ } else {
+ kfree(entry);
+ return r;
+ }
+}
+
+static struct kvstore *kvs_create_sparse_cowbtree(struct metadata *md,
+ uint32_t ksize, uint32_t vsize, uint32_t knummax,
+ bool unformatted)
+{
+ struct kvstore_cbt *kvs;
+ int r;
+
+ if (!vsize || !ksize)
+ return ERR_PTR(-ENOTSUPP);
+
+ /* We do not support two or more KVSs at the moment */
+ if (md->kvs_sparse)
+ return ERR_PTR(-EBUSY);
+
+ kvs = kmalloc(sizeof(*kvs), GFP_NOIO);
+ if (!kvs)
+ return ERR_PTR(-ENOMEM);
+
+ kvs->ckvs.vsize = vsize;
+ kvs->ckvs.ksize = ksize;
+ kvs->entry_size = vsize + ksize;
+
+ kvs->info.tm = md->tm;
+ kvs->info.levels = 1;
+ kvs->info.value_type.context = NULL;
+ kvs->info.value_type.size = kvs->entry_size;
+ kvs->info.value_type.inc = NULL;
+ kvs->info.value_type.dec = NULL;
+ kvs->info.value_type.equal = NULL;
+
+ if (!unformatted) {
+ kvs->ckvs.kvs_insert = kvs_insert_sparse_cowbtree;
+ kvs->ckvs.kvs_lookup = kvs_lookup_sparse_cowbtree;
+ kvs->ckvs.kvs_delete = kvs_delete_sparse_cowbtree;
+ kvs->ckvs.kvs_iterate = NULL;
+
+ md->kvs_sparse = kvs;
+ __begin_transaction(md);
+ } else {
+ r = dm_btree_empty(&(kvs->info), &(kvs->root));
+ if (r < 0) {
+ kvs = ERR_PTR(r);
+ goto badtree;
+ }
+
+ /* I think this should be moved below the 4 lines below */
+ flush_meta_cowbtree(md);
+
+ kvs->ckvs.kvs_insert = kvs_insert_sparse_cowbtree;
+ kvs->ckvs.kvs_lookup = kvs_lookup_sparse_cowbtree;
+ kvs->ckvs.kvs_delete = kvs_delete_sparse_cowbtree;
+ kvs->ckvs.kvs_iterate = NULL;
+
+ md->kvs_sparse = kvs;
+ }
+
+ return &(kvs->ckvs);
+
+badtree:
+ kfree(kvs);
+ return (struct kvstore *) kvs;
+}
+
+struct metadata_ops metadata_ops_cowbtree = {
+ .init_meta = init_meta_cowbtree,
+ .exit_meta = exit_meta_cowbtree,
+ .kvs_create_linear = kvs_create_linear_cowbtree,
+ .kvs_create_sparse = kvs_create_sparse_cowbtree,
+
+ .alloc_data_block = alloc_data_block_cowbtree,
+ .inc_refcount = inc_refcount_cowbtree,
+ .dec_refcount = dec_refcount_cowbtree,
+ .get_refcount = get_refcount_cowbtree,
+
+ .flush_meta = flush_meta_cowbtree,
+
+ .flush_bufio_cache = NULL,
+};
diff --git a/drivers/md/dm-dedup-cbt.h b/drivers/md/dm-dedup-cbt.h
new file mode 100644
index 0000000..8b0c629
--- /dev/null
+++ b/drivers/md/dm-dedup-cbt.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2012-2014 Vasily Tarasov
+ * Copyright (C) 2012-2014 Geoff Kuenning
+ * Copyright (C) 2012-2014 Sonam Mandal
+ * Copyright (C) 2012-2014 Karthikeyani Palanisami
+ * Copyright (C) 2012-2014 Philip Shilane
+ * Copyright (C) 2012-2014 Sagar Trehan
+ * Copyright (C) 2012-2014 Erez Zadok
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef COWBTREE_BACKEND_H
+#define COWBTREE_BACKEND_H
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-io.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/list.h>
+#include <linux/err.h>
+#include <asm/current.h>
+#include <linux/string.h>
+#include <linux/gfp.h>
+
+#include <linux/scatterlist.h>
+#include <asm/page.h>
+#include <asm/unaligned.h>
+#include <crypto/hash.h>
+#include <crypto/md5.h>
+#include <crypto/algapi.h>
+
+#include "dm-dedup-target.h"
+
+extern struct metadata_ops metadata_ops_cowbtree;
+
+struct init_param_cowbtree {
+ struct block_device *metadata_bdev;
+ uint64_t blocks;
+};
+
+#endif /* COWBTREE_BACKEND_H */
--
1.7.1
--
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