btrfs: hold a ref on the root in find_data_references

We're looking up the data references for the bytenr in a root, we need
to hold a ref on that root while we're doing that.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 0336a48d7d96a1dc10e11d3d4ab33d0fe2807cf8..976917ca412a9570e925a4c7c7df2f0b415dfaaf 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3751,7 +3751,11 @@ static int find_data_references(struct reloc_control *rc,
        root = read_fs_root(fs_info, ref_root);
        if (IS_ERR(root)) {
                err = PTR_ERR(root);
-               goto out;
+               goto out_free;
+       }
+       if (!btrfs_grab_fs_root(root)) {
+               err = -ENOENT;
+               goto out_free;
        }
 
        key.objectid = ref_objectid;
@@ -3864,6 +3868,8 @@ next:
 
        }
 out:
+       btrfs_put_fs_root(root);
+out_free:
        btrfs_free_path(path);
        return err;
 }