From 509659cde578d891445afd67d87121dd13e71596 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 10 May 2007 12:36:17 -0400 Subject: [PATCH] Btrfs: switch to crc32c instead of sha256 Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 4 +++- fs/btrfs/disk-io.c | 12 ++++++------ fs/btrfs/file-item.c | 35 +++++++++++++++++++---------------- 3 files changed, 28 insertions(+), 23 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 92a6078de827..d8caeba5d758 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -30,6 +30,8 @@ extern struct kmem_cache *btrfs_path_cachep; /* 32 bytes in various csum fields */ #define BTRFS_CSUM_SIZE 32 +/* four bytes for CRC32 */ +#define BTRFS_CRC32_SIZE 4 /* * the key defines the order in the tree, and so it also defines (optimal) @@ -235,7 +237,7 @@ struct btrfs_file_extent_item { } __attribute__ ((__packed__)); struct btrfs_csum_item { - u8 csum[BTRFS_CSUM_SIZE]; + u8 csum; } __attribute__ ((__packed__)); struct btrfs_device_item { diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 2dbf422a2b9a..678456d1e2f9 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -196,14 +196,14 @@ int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len, ret = crypto_hash_digest(&desc, &sg, 1, result); spin_unlock(&root->fs_info->hash_lock); if (ret) { - printk("sha256 digest failed\n"); + printk("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]; + char result[BTRFS_CRC32_SIZE]; int ret; struct btrfs_node *node; @@ -212,14 +212,14 @@ static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh, if (ret) return ret; if (verify) { - if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) { + if (memcmp(bh->b_data, result, BTRFS_CRC32_SIZE)) { printk("checksum verify failed on %Lu\n", bh_blocknr(bh)); return 1; } } else { node = btrfs_buffer_node(bh); - memcpy(node->header.csum, result, BTRFS_CSUM_SIZE); + memcpy(node->header.csum, result, BTRFS_CRC32_SIZE); } return 0; } @@ -576,10 +576,10 @@ struct btrfs_root *open_ctree(struct super_block *sb) sizeof(struct btrfs_key)); insert_inode_hash(fs_info->btree_inode); mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS); - fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC); + fs_info->hash_tfm = crypto_alloc_hash("crc32c", 0, CRYPTO_ALG_ASYNC); spin_lock_init(&fs_info->hash_lock); if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) { - printk("failed to allocate sha256 hash\n"); + printk("failed to allocate digest hash\n"); return NULL; } mutex_init(&fs_info->trans_mutex); diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 10e4cf08e9ed..a66709e6d036 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -4,8 +4,8 @@ #include "transaction.h" #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \ - sizeof(struct btrfs_item) * 2) / \ - sizeof(struct btrfs_csum_item)) - 1)) + sizeof(struct btrfs_item) * 2) / \ + BTRFS_CRC32_SIZE) - 1)) int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid, u64 pos, @@ -78,7 +78,7 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, csum_offset = (offset - found_key.offset) >> root->fs_info->sb->s_blocksize_bits; csums_in_item = btrfs_item_size(leaf->items + path->slots[0]); - csums_in_item /= sizeof(struct btrfs_csum_item); + csums_in_item /= BTRFS_CRC32_SIZE; if (csum_offset >= csums_in_item) { ret = -EFBIG; @@ -86,7 +86,8 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, } } item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); - item += csum_offset; + item = (struct btrfs_csum_item *)((unsigned char *)item + + csum_offset * BTRFS_CRC32_SIZE); return item; fail: if (ret > 0) @@ -143,8 +144,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans, /* we found one, but it isn't big enough yet */ leaf = btrfs_buffer_leaf(path->nodes[0]); item_size = btrfs_item_size(leaf->items + path->slots[0]); - if ((item_size / sizeof(struct btrfs_csum_item)) >= - MAX_CSUM_ITEMS(root)) { + if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) { /* already at max size, make a new one */ goto insert; } @@ -159,7 +159,7 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans, */ btrfs_release_path(root, path); ret = btrfs_search_slot(trans, root, &file_key, path, - sizeof(struct btrfs_csum_item), 1); + BTRFS_CRC32_SIZE, 1); if (ret < 0) goto fail; if (ret == 0) { @@ -180,10 +180,10 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans, goto insert; } if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) / - sizeof(struct btrfs_csum_item)) { - u32 diff = (csum_offset + 1) * sizeof(struct btrfs_csum_item); + BTRFS_CRC32_SIZE) { + u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE; diff = diff - btrfs_item_size(leaf->items + path->slots[0]); - WARN_ON(diff != sizeof(struct btrfs_csum_item)); + WARN_ON(diff != BTRFS_CRC32_SIZE); ret = btrfs_extend_item(trans, root, path, diff); BUG_ON(ret); goto csum; @@ -193,7 +193,7 @@ insert: btrfs_release_path(root, path); csum_offset = 0; ret = btrfs_insert_empty_item(trans, root, path, &file_key, - sizeof(struct btrfs_csum_item)); + BTRFS_CRC32_SIZE); if (ret != 0) { printk("at insert for %Lu %u %Lu ret is %d\n", file_key.objectid, file_key.flags, file_key.offset, ret); WARN_ON(1); @@ -203,10 +203,13 @@ csum: item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0], struct btrfs_csum_item); ret = 0; - item += csum_offset; + item = (struct btrfs_csum_item *)((unsigned char *)item + + csum_offset * BTRFS_CRC32_SIZE); found: - btrfs_check_bounds(item->csum, BTRFS_CSUM_SIZE, path->nodes[0]->b_data, root->fs_info->sb->s_blocksize); - ret = btrfs_csum_data(root, data, len, item->csum); + btrfs_check_bounds(&item->csum, BTRFS_CRC32_SIZE, + path->nodes[0]->b_data, + root->fs_info->sb->s_blocksize); + ret = btrfs_csum_data(root, data, len, &item->csum); btrfs_mark_buffer_dirty(path->nodes[0]); fail: btrfs_release_path(root, path); @@ -222,7 +225,7 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root, struct btrfs_key file_key; struct btrfs_path *path; struct btrfs_csum_item *item; - char result[BTRFS_CSUM_SIZE]; + char result[BTRFS_CRC32_SIZE]; path = btrfs_alloc_path(); BUG_ON(!path); @@ -244,7 +247,7 @@ int btrfs_csum_verify_file_block(struct btrfs_root *root, ret = btrfs_csum_data(root, data, len, result); WARN_ON(ret); - if (memcmp(result, item->csum, BTRFS_CSUM_SIZE)) + if (memcmp(result, &item->csum, BTRFS_CRC32_SIZE)) ret = 1; fail: btrfs_release_path(root, path);