[PATCH 2/2] fs/namei.c: only check mountpoint on non-negative dentry

[yan <clouds.yan@gmail.com>]

Signed-off-by: yan <clouds.yan@gmail.com>
---
 fs/namei.c |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index dd1ed1b..028f5c8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3628,11 +3628,15 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
 		return error;
 
 	dget(new_dentry);
-	if (target)
-		mutex_lock(&target->i_mutex);
 
 	error = -EBUSY;
-	if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry))
+	if (target){
+		mutex_lock(&target->i_mutex);
+		if (d_mountpoint(new_dentry))
+			goto out;
+	}
+
+	if (d_mountpoint(old_dentry))
 		goto out;
 
 	error = -EMLINK;
@@ -3671,11 +3675,15 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
 		return error;
 
 	dget(new_dentry);
-	if (target)
-		mutex_lock(&target->i_mutex);
 
 	error = -EBUSY;
-	if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
+	if (target){
+		mutex_lock(&target->i_mutex);
+		if (d_mountpoint(new_dentry))
+			goto out;
+	}
+
+	if (d_mountpoint(old_dentry))
 		goto out;
 
 	error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
-- 
1.7.9.5