Btrfs: verify csums on read
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f2c1dd4..f5db2b9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -127,31 +127,46 @@
return 0;
}
-static int csum_tree_block(struct btrfs_root * root, struct buffer_head *bh,
- int verify)
+int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
+ char *result)
{
- struct btrfs_node *node = btrfs_buffer_node(bh);
struct scatterlist sg;
struct crypto_hash *tfm = root->fs_info->hash_tfm;
struct hash_desc desc;
int ret;
- char result[32];
desc.tfm = tfm;
desc.flags = 0;
- sg_init_one(&sg, bh->b_data + 32, bh->b_size - 32);
+ sg_init_one(&sg, data, len);
spin_lock(&root->fs_info->hash_lock);
- ret = crypto_hash_digest(&desc, &sg, bh->b_size - 32, result);
+ ret = crypto_hash_digest(&desc, &sg, len, result);
spin_unlock(&root->fs_info->hash_lock);
if (ret) {
printk("sha256 digest failed\n");
}
+ return ret;
+}
+static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
+ int verify)
+{
+ char result[BTRFS_CSUM_SIZE];
+ int ret;
+ struct btrfs_node *node;
+
+ ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
+ bh->b_size - BTRFS_CSUM_SIZE, result);
+ if (ret)
+ return ret;
if (verify) {
- if (memcmp(node->header.csum, result, sizeof(result)))
- printk("csum verify failed on %Lu\n", bh->b_blocknr);
- return -EINVAL;
- } else
- memcpy(node->header.csum, result, sizeof(node->header.csum));
+ if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
+ printk("checksum verify failed on %lu\n",
+ bh->b_blocknr);
+ return 1;
+ }
+ } else {
+ node = btrfs_buffer_node(bh);
+ memcpy(&node->header.csum, result, BTRFS_CSUM_SIZE);
+ }
return 0;
}