Btrfs: fix wrong return value of btrfs_lookup_csum()

If we don't find the expected csum item, but find a csum item which is
adjacent to the specified extent, we should return -EFBIG, or we should
return -ENOENT. But btrfs_lookup_csum() return -EFBIG even the csum item
is not adjacent to the specified extent. Fix it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index b7e529d2860f..c4628a201cb3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -118,9 +118,11 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
                 csums_in_item /= csum_size;
 
-                if (csum_offset >= csums_in_item) {
+                if (csum_offset == csums_in_item) {
                         ret = -EFBIG;
                         goto fail;
+                } else if (csum_offset > csums_in_item) {
+                        goto fail;
                 }
         }
         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);