1 files changed, 26 insertions, 6 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index c35ffdc12bba..655f21f99160 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -255,7 +255,7 @@ static int mknod_ptmx(struct super_block *sb)
 	if (!uid_valid(root_uid) || !gid_valid(root_gid))
 		return -EINVAL;
 
-	mutex_lock(&d_inode(root)->i_mutex);
+	inode_lock(d_inode(root));
 
 	/* If we have already created ptmx node, return */
 	if (fsi->ptmx_dentry) {
@@ -292,7 +292,7 @@ static int mknod_ptmx(struct super_block *sb)
 	fsi->ptmx_dentry = dentry;
 	rc = 0;
 out:
-	mutex_unlock(&d_inode(root)->i_mutex);
+	inode_unlock(d_inode(root));
 	return rc;
 }
 
@@ -575,6 +575,26 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
 	mutex_unlock(&allocated_ptys_lock);
 }
 
+/*
+ * pty code needs to hold extra references in case of last /dev/tty close
+ */
+
+void devpts_add_ref(struct inode *ptmx_inode)
+{
+	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+
+	atomic_inc(&sb->s_active);
+	ihold(ptmx_inode);
+}
+
+void devpts_del_ref(struct inode *ptmx_inode)
+{
+	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+
+	iput(ptmx_inode);
+	deactivate_super(sb);
+}
+
 /**
  * devpts_pty_new -- create a new inode in /dev/pts/
  * @ptmx_inode: inode of the master
@@ -615,7 +635,7 @@ struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
 
 	sprintf(s, "%d", index);
 
-	mutex_lock(&d_inode(root)->i_mutex);
+	inode_lock(d_inode(root));
 
 	dentry = d_alloc_name(root, s);
 	if (dentry) {
@@ -626,7 +646,7 @@ struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
 		inode = ERR_PTR(-ENOMEM);
 	}
 
-	mutex_unlock(&d_inode(root)->i_mutex);
+	inode_unlock(d_inode(root));
 
 	return inode;
 }
@@ -671,7 +691,7 @@ void devpts_pty_kill(struct inode *inode)
 
 	BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
 
-	mutex_lock(&d_inode(root)->i_mutex);
+	inode_lock(d_inode(root));
 
 	dentry = d_find_alias(inode);
 
@@ -680,7 +700,7 @@ void devpts_pty_kill(struct inode *inode)
 	dput(dentry);	/* d_alloc_name() in devpts_pty_new() */
 	dput(dentry);		/* d_find_alias above */
 
-	mutex_unlock(&d_inode(root)->i_mutex);
+	inode_unlock(d_inode(root));
 }
 
 static int __init init_devpts_fs(void)