[PATCH v5 07/19] btrfs: dedup: Implement btrfs_dedup_calc_hash interface
From: Qu Wenruo <hidden>
Date: 2016-02-02 03:08:02
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
From: Wang Xiaoguang <redacted> 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 <redacted> Signed-off-by: Wang Xiaoguang <redacted> --- fs/btrfs/dedup.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+)
diff --git a/fs/btrfs/dedup.c b/fs/btrfs/dedup.c
index 20749ce..f6b518a 100644
--- a/fs/btrfs/dedup.c
+++ b/fs/btrfs/dedup.c@@ -516,3 +516,46 @@ int btrfs_dedup_search(struct btrfs_dedup_info *dedup_info, } return ret; } + +int btrfs_dedup_calc_hash(struct btrfs_dedup_info *dedup_info, + struct inode *inode, u64 start, + struct btrfs_dedup_hash *hash) +{ + int i; + int ret; + struct page *p; + struct crypto_shash *tfm = dedup_info->dedup_driver; + struct { + struct shash_desc desc; + char ctx[crypto_shash_descsize(tfm)]; + } sdesc; + u64 dedup_bs = dedup_info->blocksize; + u64 sectorsize = BTRFS_I(inode)->root->sectorsize; + + if (!dedup_info || !hash) + return 0; + + WARN_ON(!IS_ALIGNED(start, sectorsize)); + + sdesc.desc.tfm = tfm; + sdesc.desc.flags = 0; + ret = crypto_shash_init(&sdesc.desc); + if (ret) + return ret; + for (i = 0; sectorsize * i < dedup_bs; i++) { + char *d; + + p = find_get_page(inode->i_mapping, + (start >> PAGE_CACHE_SHIFT) + i); + if (WARN_ON(!p)) + return -ENOENT; + d = kmap(p); + ret = crypto_shash_update(&sdesc.desc, d, sectorsize); + kunmap(p); + page_cache_release(p); + if (ret) + return ret; + } + ret = crypto_shash_final(&sdesc.desc, hash->hash); + return ret; +}
--
2.7.0