diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index e4963da4dd081..7f91d62c2225a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2463,30 +2463,16 @@ static int btrfs_unfreeze(struct super_block *sb) static int btrfs_show_devname(struct seq_file *m, struct dentry *root) { struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb); - struct btrfs_device *dev, *first_dev = NULL; /* - * Lightweight locking of the devices. We should not need - * device_list_mutex here as we only read the device data and the list - * is protected by RCU. Even if a device is deleted during the list - * traversals, we'll get valid data, the freeing callback will wait at - * least until the rcu_read_unlock. + * There should be always a valid pointer in latest_dev, it may be stale + * for a short moment in case it's being deleted but still valid until + * the end of RCU grace period. */ rcu_read_lock(); - list_for_each_entry_rcu(dev, &fs_info->fs_devices->devices, dev_list) { - if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) - continue; - if (!dev->name) - continue; - if (!first_dev || dev->devid < first_dev->devid) - first_dev = dev; - } - - if (first_dev) - seq_escape(m, rcu_str_deref(first_dev->name), " \t\n\\"); - else - WARN_ON(1); + seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), " \t\n\\"); rcu_read_unlock(); + return 0; }