btrfs: hold a ref on the root in record_reloc_root_in_trans

We are recording this root in the transaction, so we need to hold a ref
on it until we do 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 679dd3958ff257f3086d71fae14f219320c0f14c..0336a48d7d96a1dc10e11d3d4ab33d0fe2807cf8 100644 (file)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2648,15 +2648,19 @@ static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
 {
        struct btrfs_fs_info *fs_info = reloc_root->fs_info;
        struct btrfs_root *root;
+       int ret;
 
        if (reloc_root->last_trans == trans->transid)
                return 0;
 
        root = read_fs_root(fs_info, reloc_root->root_key.offset);
        BUG_ON(IS_ERR(root));
+       BUG_ON(!btrfs_grab_fs_root(root));
        BUG_ON(root->reloc_root != reloc_root);
+       ret = btrfs_record_root_in_trans(trans, root);
+       btrfs_put_fs_root(root);
 
-       return btrfs_record_root_in_trans(trans, root);
+       return ret;
 }
 
 static noinline_for_stack