erofs: relinquish volume with mutex held

Relinquish fscache volume with mutex held.  Otherwise if a new domain is
registered when the old domain with the same name gets removed from the
list but not relinquished yet, fscache may complain the collision.

Fixes: 8b7adf1d ("erofs: introduce fscache-based domain")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Link: https://lore.kernel.org/r/20230209063913.46341-4-jefflexu@linux.alibaba.comSigned-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

fs/erofs/fscache.c

@@ -326,8 +326,8 @@ static void erofs_fscache_domain_put(struct erofs_domain *domain)
 			kern_unmount(erofs_pseudo_mnt);
 			erofs_pseudo_mnt = NULL;
 		}
-		mutex_unlock(&erofs_domain_list_lock);
 		fscache_relinquish_volume(domain->volume, NULL, false);
+		mutex_unlock(&erofs_domain_list_lock);
 		kfree(domain->domain_id);
 		kfree(domain);
 		return;