btrfs: hold a ref for the root in btrfs_find_orphan_roots

We lookup roots for every orphan item we have, we need to hold a ref on
the root while we're doing this work.

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/root-tree.c b/fs/btrfs/root-tree.c
index 1ea4a35a0830fe46cd8c7b630bcb597ec44fefae..a32632f439870b51b92701bac4a5b7e83fb94e12 100644 (file)
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -257,6 +257,8 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
 
                root = btrfs_get_fs_root(fs_info, &root_key, false);
                err = PTR_ERR_OR_ZERO(root);
+               if (!err && !btrfs_grab_fs_root(root))
+                       err = -ENOENT;
                if (err && err != -ENOENT) {
                        break;
                } else if (err == -ENOENT) {
@@ -287,6 +289,7 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
                        set_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
                        btrfs_add_dead_root(root);
                }
+               btrfs_put_fs_root(root);
        }
 
        btrfs_free_path(path);