From: Wang Xiaoguang <wangxg.f...@cn.fujitsu.com>
Introduce the header for btrfs online(write time) de-duplication
framework and needed header.
The new de-duplication framework is going to support 2 different dedup
method and 1 dedup hash.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
Signed-off-by: Wang Xiaoguang <wangxg.f...@cn.fujitsu.com>
---
fs/btrfs/ctree.h | 3 ++
fs/btrfs/dedup.h | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 131 insertions(+)
create mode 100644 fs/btrfs/dedup.h
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4c23f34..62fed1d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1816,6 +1816,9 @@ struct btrfs_fs_info {
* and will be latter freed. Protected by fs_info->chunk_mutex.
*/
struct list_head pinned_chunks;
+
+ /* reference to inband de-duplication info */
+ struct btrfs_dedup_info *dedup_info;
};
struct btrfs_subvolume_writers {
diff --git a/fs/btrfs/dedup.h b/fs/btrfs/dedup.h
new file mode 100644
index 0000000..fd2e392
--- /dev/null
+++ b/fs/btrfs/dedup.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2015 Fujitsu. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __BTRFS_DEDUP__
+#define __BTRFS_DEDUP__
+
+#include <linux/btrfs.h>
+#include <crypto/hash.h>
+
+/*
+ * Dedup storage backend
+ * On disk is persist storage but overhead is large
+ * In memory is fast but will lose all its hash on umount
+ */
+#define BTRFS_DEDUP_BACKEND_INMEMORY 0
+#define BTRFS_DEDUP_BACKEND_ONDISK 1
+#define BTRFS_DEDUP_BACKEND_LAST 2
+
+/* Dedup block size limit and default value */
+#define BTRFS_DEDUP_BLOCKSIZE_MAX (128 * 1024)
+#define BTRFS_DEDUP_BLOCKSIZE_MIN (16 * 1024)
+#define BTRFS_DEDUP_BLOCKSIZE_DEFAULT (32 * 1024)
+
+/* Hash algorithm, only support SHA256 yet */
+#define BTRFS_DEDUP_HASH_SHA256 0
+
+static int btrfs_dedup_sizes[] = { 32 };
+
+struct btrfs_dedup_hash {
+ /*
+ * hash_node is for hash -> extent search(dedup search).
+ * bytenr_node is for extent(bytenr) -> hash search(free extent).
+ * lru_list is to maintain low memory usage. Currently they are
+ * only used in in-memory dedup mode.
+ */
+ struct rb_node hash_node;
+ struct rb_node bytenr_node;
+ struct list_head lru_list;
+
+ u64 bytenr;
+ u64 num_bytes;
+
+ /* last field is a variable length array of dedup hash */
+ u8 hash[];
+};
+
+struct btrfs_dedup_info {
+ /* dedup blocksize */
+ u64 blocksize;
+ u16 backend;
+ u16 hash_type;
+
+ /* Hash driver */
+ struct crypto_shash *dedup_driver;
+
+ /* following members are only used in in-memory dedup mode */
+ struct rb_root hash_root;
+ struct rb_root bytenr_root;
+ struct list_head lru_list;
+ spinlock_t lock;
+ u64 limit_nr;
+ u64 current_nr;
+};
+
+struct btrfs_trans_handle;
+
+int btrfs_dedup_hash_size(u16 type);
+struct btrfs_dedup_hash *btrfs_dedup_alloc_hash(u16 type);
+
+/*
+ * Initial inband dedup info
+ * Called at either dedup enable or mount time.
+ */
+int btrfs_dedup_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend,
+ u64 blocksize, u64 limit);
+
+/*
+ * Disable dedup and invalidate all its dedup data.
+ * Called at dedup disable time.
+ */
+int btrfs_dedup_disable(struct btrfs_fs_info *fs_info);
+
+/*
+ * Calculate hash for dedup.
+ * Caller must ensure [start, start + dedup_bs) has valid data.
+ */
+int btrfs_dedup_calc_hash(struct btrfs_root *root, struct inode *inode,
+ u64 start, struct btrfs_dedup_hash *hash);
+
+/*
+ * Search for duplicated extents by calculated hash
+ * Caller must call btrfs_dedup_calc_hash() first to get the hash.
+ *
+ * @inode: the inode for we are writing
+ * @file_pos: offset inside the inode
+ * As we will increase extent ref immediately after a hash match,
+ * we need @file_pos and @inode in this case.
+ *
+ * Return > 0 for a hash match, and the extent ref will be
+ * INCREASED.
+ * Return 0 for a hash miss. Nothing is done
+ */
+int btrfs_dedup_search(struct inode *inode, u64 file_pos,
+ struct btrfs_dedup_hash *hash);
+
+/* Add a dedup hash into dedup tree */
+int btrfs_dedup_add(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_dedup_hash *hash);
+
+/* Remove a dedup hash from dedup tree */
+int btrfs_dedup_del(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ u64 bytenr);
+#endif
--
2.6.4
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