On Thu, Jan 14, 2016 at 5:57 AM, Qu Wenruo <quwenruo@xxxxxxxxxxxxxx> wrote:
> From: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
>
> 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 <quwenruo@xxxxxxxxxxxxxx>
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/dedup.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
>
> diff --git a/fs/btrfs/dedup.c b/fs/btrfs/dedup.c
> index d6ee576..8860916 100644
> --- a/fs/btrfs/dedup.c
> +++ b/fs/btrfs/dedup.c
> @@ -465,3 +465,60 @@ 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);
If !p, we should return with an error too, otherwise we'll get a null
pointer dereference below.
> + 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;
> +}
> --
> 2.7.0
>
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
