From: Wang Xiaoguang <wangxg.f...@cn.fujitsu.com>
Unlike in-memory or on-disk dedup method, only SHA256 hash method is
supported yet, so implement btrfs_dedup_calc_hash() interface using
SHA256.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
Signed-off-by: Wang Xiaoguang <wangxg.f...@cn.fujitsu.com>
---
fs/btrfs/dedup.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/fs/btrfs/dedup.c b/fs/btrfs/dedup.c
index 4863cf2..4f24a2c 100644
--- a/fs/btrfs/dedup.c
+++ b/fs/btrfs/dedup.c
@@ -499,3 +499,60 @@ int btrfs_dedup_search(struct inode *inode, u64 file_pos,
}
return ret;
}
+
+static int hash_data(struct btrfs_dedup_info *dedup_info, const char *data,
+ u64 length, struct btrfs_dedup_hash *hash)
+{
+ struct crypto_shash *tfm = dedup_info->dedup_driver;
+ struct {
+ struct shash_desc desc;
+ char ctx[crypto_shash_descsize(tfm)];
+ } sdesc;
+ int ret;
+
+ sdesc.desc.tfm = tfm;
+ sdesc.desc.flags = 0;
+
+ ret = crypto_shash_digest(&sdesc.desc, data, length,
+ (char *)(hash->hash));
+ return ret;
+}
+
+int btrfs_dedup_calc_hash(struct btrfs_root *root, struct inode *inode,
+ u64 start, struct btrfs_dedup_hash *hash)
+{
+ struct page *p;
+ struct btrfs_dedup_info *dedup_info = root->fs_info->dedup_info;
+ char *data;
+ int i;
+ int ret;
+ u64 dedup_bs;
+ u64 sectorsize = root->sectorsize;
+
+ if (!dedup_info || !hash)
+ return 0;
+
+ WARN_ON(!IS_ALIGNED(start, sectorsize));
+
+ dedup_bs = dedup_info->blocksize;
+ sectorsize = root->sectorsize;
+
+ data = kmalloc(dedup_bs, GFP_NOFS);
+ if (!data)
+ return -ENOMEM;
+ for (i = 0; sectorsize * i < dedup_bs; i++) {
+ char *d;
+
+ /* TODO: Add support for subpage size case */
+ p = find_get_page(inode->i_mapping,
+ (start >> PAGE_CACHE_SHIFT) + i);
+ WARN_ON(!p);
+ d = kmap_atomic(p);
+ memcpy((data + sectorsize * i), d, sectorsize);
+ kunmap_atomic(d);
+ page_cache_release(p);
+ }
+ ret = hash_data(dedup_info, data, dedup_bs, hash);
+ kfree(data);
+ return ret;
+}
--
2.6.4
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
