5 files changed, 60 insertions, 36 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 6ba5394834be..df090bf2eec0 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -158,6 +158,8 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
         } else {
                 root_gen = 0;
         }
+        if (!(buf->flags & EXTENT_CSUM))
+                WARN_ON(1);
 
         WARN_ON(root->ref_cows && trans->transid !=
                 root->fs_info->running_transaction->transid);
@@ -245,6 +247,8 @@ int btrfs_cow_block(struct btrfs_trans_handle *trans,
                        root->fs_info->generation);
                 WARN_ON(1);
         }
+        if (!(buf->flags & EXTENT_CSUM))
+                WARN_ON(1);
 
         header_trans = btrfs_header_generation(buf);
         spin_lock(&root->fs_info->hash_lock);
@@ -396,6 +400,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                 if (search_start == 0)
                         search_start = last_block;
 
+                btrfs_verify_block_csum(root, cur);
                 err = __btrfs_cow_block(trans, root, cur, parent, i,
                                         &tmp, search_start,
                                         min(16 * blocksize,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5547607681f4..e40fb318ad99 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -46,27 +46,6 @@ static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
 
 static struct extent_io_ops btree_extent_io_ops;
 
-struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
-                                            u64 bytenr, u32 blocksize)
-{
-        struct inode *btree_inode = root->fs_info->btree_inode;
-        struct extent_buffer *eb;
-        eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
-                                bytenr, blocksize, GFP_NOFS);
-        return eb;
-}
-
-struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
-                                                 u64 bytenr, u32 blocksize)
-{
-        struct inode *btree_inode = root->fs_info->btree_inode;
-        struct extent_buffer *eb;
-
-        eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
-                                 bytenr, blocksize, NULL, GFP_NOFS);
-        return eb;
-}
-
 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
                                     size_t page_offset, u64 start, u64 len,
                                     int create)
@@ -380,36 +359,29 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
         return 0;
 }
 
-struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
-                                      u32 blocksize)
+int btrfs_verify_block_csum(struct btrfs_root *root,
+                            struct extent_buffer *buf)
 {
-        struct extent_buffer *buf = NULL;
-        struct inode *btree_inode = root->fs_info->btree_inode;
         struct extent_io_tree *io_tree;
         u64 end;
         int ret;
 
-        io_tree = &BTRFS_I(btree_inode)->io_tree;
-
-        buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
-        if (!buf)
-                return NULL;
-        read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1,
-                                 btree_get_extent);
-
+        io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
         if (buf->flags & EXTENT_CSUM)
-                return buf;
+                return 0;
 
-        end = buf->start + PAGE_CACHE_SIZE - 1;
+        end = min_t(u64, buf->len, PAGE_CACHE_SIZE);
+        end = buf->start + end - 1;
         if (test_range_bit(io_tree, buf->start, end, EXTENT_CSUM, 1)) {
                 buf->flags |= EXTENT_CSUM;
-                return buf;
+                return 0;
         }
 
         lock_extent(io_tree, buf->start, end, GFP_NOFS);
 
         if (test_range_bit(io_tree, buf->start, end, EXTENT_CSUM, 1)) {
                 buf->flags |= EXTENT_CSUM;
+                ret = 0;
                 goto out_unlock;
         }
 
@@ -419,6 +391,48 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 
 out_unlock:
         unlock_extent(io_tree, buf->start, end, GFP_NOFS);
+        return ret;
+}
+
+struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
+                                            u64 bytenr, u32 blocksize)
+{
+        struct inode *btree_inode = root->fs_info->btree_inode;
+        struct extent_buffer *eb;
+        eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
+                                bytenr, blocksize, GFP_NOFS);
+        return eb;
+}
+
+struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
+                                                 u64 bytenr, u32 blocksize)
+{
+        struct inode *btree_inode = root->fs_info->btree_inode;
+        struct extent_buffer *eb;
+
+        eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
+                                 bytenr, blocksize, NULL, GFP_NOFS);
+        return eb;
+}
+
+
+struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
+                                      u32 blocksize)
+{
+        struct extent_buffer *buf = NULL;
+        struct inode *btree_inode = root->fs_info->btree_inode;
+        struct extent_io_tree *io_tree;
+        int ret;
+
+        io_tree = &BTRFS_I(btree_inode)->io_tree;
+
+        buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
+        if (!buf)
+                return NULL;
+        read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1,
+                                 btree_get_extent);
+
+        ret = btrfs_verify_block_csum(root, buf);
         return buf;
 }
 
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index b7cbc58a5553..05b88d0e75eb 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -69,4 +69,6 @@ u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len);
 void btrfs_csum_final(u32 crc, char *result);
 void btrfs_throttle(struct btrfs_root *root);
 int btrfs_open_device(struct btrfs_device *dev);
+int btrfs_verify_block_csum(struct btrfs_root *root,
+                            struct extent_buffer *buf);
 #endif
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index cf283b0271ac..a34c289aec21 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2069,6 +2069,8 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
                                 BUG_ON(ret);
                                 continue;
                         }
+                } else if (next) {
+                        btrfs_verify_block_csum(root, next);
                 }
                 WARN_ON(*level <= 0);
                 if (path->nodes[*level-1])
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index 5935cbd8f2b8..256af1870eef 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -101,6 +101,7 @@ static int defrag_walk_down(struct btrfs_trans_handle *trans,
                                 path->slots[*level]++;
                                 continue;
                         }
+                        btrfs_verify_block_csum(root, next);
                 } else {
                         next = read_tree_block(root, bytenr,
                                        btrfs_level_size(root, *level - 1));