1 files changed, 8 insertions, 0 deletions

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 7d3ed6bfcfa..cbd4e18adb2 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -483,6 +483,7 @@ out:
 }
 
 struct kmem_cache *ecryptfs_sb_info_cache;
+static struct file_system_type ecryptfs_fs_type;
 
 /**
  * ecryptfs_read_super
@@ -503,6 +504,13 @@ static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
                 goto out;
         }
+        if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
+                rc = -EINVAL;
+                printk(KERN_ERR "Mount on filesystem of type "
+                        "eCryptfs explicitly disallowed due to "
+                        "known incompatibilities\n");
+                goto out_free;
+        }
         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
         sb->s_blocksize = path.dentry->d_sb->s_blocksize;