Filipe Manana wrote on 2016/01/14 10:08 +0000:
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.
Right, and that's also true for all the caller of find_get_page() in btrfs. I'll also locate and fix them in another patch before btrfs dedup patchset. Thanks for the review and hint. Qu
+ 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
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