Btrfs: Add back file data checksumming

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 10 insertions, 11 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 80f84b48a70f..ac69f6926afc 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -135,7 +135,7 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         struct btrfs_csum_item *item;
         struct btrfs_path *path = NULL;
-        u64 private;
+        u32 csum;
 
         mutex_lock(&root->fs_info->fs_mutex);
         path = btrfs_alloc_path();
@@ -145,11 +145,12 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
                 /* a csum that isn't present is a preallocated region. */
                 if (ret == -ENOENT || ret == -EFBIG)
                         ret = 0;
-                private = 0;
+                csum = 0;
                 goto out;
         }
-        memcpy((char *)&private, &item->csum, BTRFS_CRC32_SIZE);
-        set_state_private(em_tree, start, private);
+        read_extent_buffer(path->nodes[0], &csum, (unsigned long)item,
+                           BTRFS_CRC32_SIZE);
+        set_state_private(em_tree, start, csum);
 out:
         if (path)
                 btrfs_free_path(path);
@@ -165,21 +166,19 @@ int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end)
         char *kaddr;
         u64 private;
         int ret;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        u32 csum = ~(u32)0;
 
         ret = get_state_private(em_tree, start, &private);
         kaddr = kmap_atomic(page, KM_IRQ0);
         if (ret) {
                 goto zeroit;
         }
-        /*
-        struct btrfs_root *root = BTRFS_I(inode)->root;
-        char csum[BTRFS_CRC32_SIZE];
-        ret = btrfs_csum_data(root, kaddr + offset, end - start + 1, csum);
-        BUG_ON(ret);
-        if (memcmp(csum, &private, BTRFS_CRC32_SIZE)) {
+        csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
+        btrfs_csum_final(csum, (char *)&csum);
+        if (csum != private) {
                 goto zeroit;
         }
-        */
         kunmap_atomic(kaddr, KM_IRQ0);
         return 0;