2 files changed, 3 insertions, 1 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index a5ff19b34b21..70af24aa582b 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -150,7 +150,6 @@ int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 
         path = btrfs_alloc_path();
-        path->reada = 2;
 
         WARN_ON(bio->bi_vcnt <= 0);
 
@@ -177,6 +176,7 @@ int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
                                 printk("no csum found for inode %lu start "
                                        "%llu\n", inode->i_ino,
                                        (unsigned long long)offset);
+                                item = NULL;
                                 goto found;
                         }
                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 76365ad9bfbf..640648c66b22 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -376,7 +376,9 @@ int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
         if (!(rw & (1 << BIO_RW))) {
                 if (!btrfs_test_opt(root, NODATASUM) &&
                     !btrfs_test_flag(inode, NODATASUM)) {
+                        mutex_lock(&BTRFS_I(inode)->csum_mutex);
                         btrfs_lookup_bio_sums(root, inode, bio);
+                        mutex_unlock(&BTRFS_I(inode)->csum_mutex);
                 }
                 goto mapit;
         }