Re: [PATCH v10 20/21] btrfs: dedupe: Add support for adding hash for on-disk backend

[Josef Bacik]

On 04/01/2016 02:35 AM, Qu Wenruo wrote:

Now on-disk backend can add hash now.

Since all needed on-disk backend functions are added, also allow on-disk
backend to be used, by changing DEDUPE_BACKEND_COUNT from 1(inmemory
only) to 2 (inmemory + ondisk).

Signed-off-by: Wang Xiaoguang 
Signed-off-by: Qu Wenruo 
---
 fs/btrfs/dedupe.c | 83 +++
 fs/btrfs/dedupe.h |  3 +-
 2 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
index 7c5d58a..1f0178e 100644
--- a/fs/btrfs/dedupe.c
+++ b/fs/btrfs/dedupe.c
@@ -437,6 +437,87 @@ out:
return 0;
 }

+static int ondisk_search_bytenr(struct btrfs_trans_handle *trans,
+   struct btrfs_dedupe_info *dedupe_info,
+   struct btrfs_path *path, u64 bytenr,
+   int prepare_del);
+static int ondisk_search_hash(struct btrfs_dedupe_info *dedupe_info, u8 *hash,
+ u64 *bytenr_ret, u32 *num_bytes_ret);
+static int ondisk_add(struct btrfs_trans_handle *trans,
+ struct btrfs_dedupe_info *dedupe_info,
+ struct btrfs_dedupe_hash *hash)
+{
+   struct btrfs_path *path;
+   struct btrfs_root *dedupe_root = dedupe_info->dedupe_root;
+   struct btrfs_key key;
+   u64 hash_offset;
+   u64 bytenr;
+   u32 num_bytes;
+   int hash_len = btrfs_dedupe_sizes[dedupe_info->hash_type];
+   int ret;
+
+   if (WARN_ON(hash_len <= 8 ||
+   !IS_ALIGNED(hash->bytenr, dedupe_root->sectorsize)))
+   return -EINVAL;
+
+   path = btrfs_alloc_path();
+   if (!path)
+   return -ENOMEM;
+
+   mutex_lock(_info->lock);
+
+   ret = ondisk_search_bytenr(NULL, dedupe_info, path, hash->bytenr, 0);
+   if (ret < 0)
+   goto out;
+   if (ret > 0) {
+   ret = 0;
+   goto out;
+   }
+   btrfs_release_path(path);
+
+   ret = ondisk_search_hash(dedupe_info, hash->hash, , _bytes);
+   if (ret < 0)
+   goto out;
+   /* Same hash found, don't re-add to save dedupe tree space */
+   if (ret > 0) {
+   ret = 0;
+   goto out;
+   }
+
+   /* Insert hash->bytenr item */
+   memcpy(, hash->hash + hash_len - 8, 8);


No magic numbers please.  Thanks,

Josef
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[PATCH v10 20/21] btrfs: dedupe: Add support for adding hash for on-disk backend

[Qu Wenruo]

Now on-disk backend can add hash now.

Since all needed on-disk backend functions are added, also allow on-disk
backend to be used, by changing DEDUPE_BACKEND_COUNT from 1(inmemory
only) to 2 (inmemory + ondisk).

Signed-off-by: Wang Xiaoguang 
Signed-off-by: Qu Wenruo 
---
 fs/btrfs/dedupe.c | 83 +++
 fs/btrfs/dedupe.h |  3 +-
 2 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
index 7c5d58a..1f0178e 100644
--- a/fs/btrfs/dedupe.c
+++ b/fs/btrfs/dedupe.c
@@ -437,6 +437,87 @@ out:
return 0;
 }
 
+static int ondisk_search_bytenr(struct btrfs_trans_handle *trans,
+   struct btrfs_dedupe_info *dedupe_info,
+   struct btrfs_path *path, u64 bytenr,
+   int prepare_del);
+static int ondisk_search_hash(struct btrfs_dedupe_info *dedupe_info, u8 *hash,
+ u64 *bytenr_ret, u32 *num_bytes_ret);
+static int ondisk_add(struct btrfs_trans_handle *trans,
+ struct btrfs_dedupe_info *dedupe_info,
+ struct btrfs_dedupe_hash *hash)
+{
+   struct btrfs_path *path;
+   struct btrfs_root *dedupe_root = dedupe_info->dedupe_root;
+   struct btrfs_key key;
+   u64 hash_offset;
+   u64 bytenr;
+   u32 num_bytes;
+   int hash_len = btrfs_dedupe_sizes[dedupe_info->hash_type];
+   int ret;
+
+   if (WARN_ON(hash_len <= 8 ||
+   !IS_ALIGNED(hash->bytenr, dedupe_root->sectorsize)))
+   return -EINVAL;
+
+   path = btrfs_alloc_path();
+   if (!path)
+   return -ENOMEM;
+
+   mutex_lock(_info->lock);
+
+   ret = ondisk_search_bytenr(NULL, dedupe_info, path, hash->bytenr, 0);
+   if (ret < 0)
+   goto out;
+   if (ret > 0) {
+   ret = 0;
+   goto out;
+   }
+   btrfs_release_path(path);
+
+   ret = ondisk_search_hash(dedupe_info, hash->hash, , _bytes);
+   if (ret < 0)
+   goto out;
+   /* Same hash found, don't re-add to save dedupe tree space */
+   if (ret > 0) {
+   ret = 0;
+   goto out;
+   }
+
+   /* Insert hash->bytenr item */
+   memcpy(, hash->hash + hash_len - 8, 8);
+   key.type = BTRFS_DEDUPE_HASH_ITEM_KEY;
+   key.offset = hash->bytenr;
+
+   /* The last 8 bit will not be included into hash */
+   ret = btrfs_insert_empty_item(trans, dedupe_root, path, ,
+ hash_len - 8);
+   WARN_ON(ret == -EEXIST);
+   if (ret < 0)
+   goto out;
+   hash_offset = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
+   write_extent_buffer(path->nodes[0], hash->hash,
+   hash_offset, hash_len - 8);
+   btrfs_mark_buffer_dirty(path->nodes[0]);
+   btrfs_release_path(path);
+
+   /* Then bytenr->hash item */
+   key.objectid = hash->bytenr;
+   key.type = BTRFS_DEDUPE_BYTENR_ITEM_KEY;
+   memcpy(, hash->hash + hash_len - 8, 8);
+
+   ret = btrfs_insert_empty_item(trans, dedupe_root, path, , 0);
+   WARN_ON(ret == -EEXIST);
+   if (ret < 0)
+   goto out;
+   btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+   mutex_unlock(_info->lock);
+   btrfs_free_path(path);
+   return ret;
+}
+
 int btrfs_dedupe_add(struct btrfs_trans_handle *trans,
 struct btrfs_fs_info *fs_info,
 struct btrfs_dedupe_hash *hash)
@@ -458,6 +539,8 @@ int btrfs_dedupe_add(struct btrfs_trans_handle *trans,
 
if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
return inmem_add(dedupe_info, hash);
+   if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_ONDISK)
+   return ondisk_add(trans, dedupe_info, hash);
return -EINVAL;
 }
 
diff --git a/fs/btrfs/dedupe.h b/fs/btrfs/dedupe.h
index bfcacd7..1573456 100644
--- a/fs/btrfs/dedupe.h
+++ b/fs/btrfs/dedupe.h
@@ -31,8 +31,7 @@
 #define BTRFS_DEDUPE_BACKEND_INMEMORY  0
 #define BTRFS_DEDUPE_BACKEND_ONDISK1
 
-/* Only support inmemory yet, so count is still only 1 */
-#define BTRFS_DEDUPE_BACKEND_COUNT 1
+#define BTRFS_DEDUPE_BACKEND_COUNT 2
 
 /* Dedup block size limit and default value */
 #define BTRFS_DEDUPE_BLOCKSIZE_MAX (8 * 1024 * 1024)
-- 
2.7.4



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