From 16780cabb877dbd0c8c5e9ff9bdebd6c5bdd1a7b Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Mon, 20 Feb 2012 22:14:55 -0500
Subject: Btrfs: add extra sanity checks on the path names in btrfs_mksubvol

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
 fs/btrfs/ioctl.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e9bdb8b783e5..05446f77f99b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1333,6 +1333,12 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
 		goto out;
 	}
 
+	if (name[0] == '.' &&
+	   (namelen == 1 || (name[1] == '.' && namelen == 2))) {
+		ret = -EEXIST;
+		goto out;
+	}
+
 	if (subvol) {
 		ret = btrfs_mksubvol(&file->f_path, name, namelen,
 				     NULL, transid, readonly);
-- 
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